bims-ecemfi Biomed News
on ECM and fibroblasts
Issue of 2024–05–26
48 papers selected by
Badri Narayanan Narasimhan, University of California, San Diego
  1. Modeling Physical Forces Experienced by Cancer and Stromal Cells Within Different Organ-Specific Tumor Tissue.
  2. Confinement induces internal flows in adherent cell aggregates.
  3. Mechanical heterogeneity in a soft biomaterial niche controls BMP2 signaling.
  4. Heat-inducible CAR-T overcomes adverse mechanical tumor microenvironment in a 3D bioprinted glioblastoma model.
  5. Fabrication and Characterization of Colorectal Cancer Organoids from SW1222 Cell Line in Ultrashort Self-Assembling Peptide Matrix.
  6. Softening the tumor matrix through cholesterol depletion breaks the physical barrier for enhanced antitumor therapy.
  7. Schiff base crosslinked hyaluronic acid hydrogels with tunable and cell instructive time-dependent mechanical properties.
  8. Extracellular Matrix Stiffness-Induced Mechanotransduction of Capillarized Liver Sinusoidal Endothelial Cells.
  9. Cadherin Expression is Regulated by Mechanical Phenotypes of Fibroblasts in the Perivascular Matrix.
  10. Laminin I mediates resistance to lapatinib in HER2-positive brain metastatic breast cancer cells in vitro.
  11. Heterogeneity of brain extracellular matrix and astrocyte activation.
  12. Biomechanical activation of keloid fibroblasts promotes lysosomal remodelling and exocytosis.
  13. E-cadherin tunes tissue mechanical behavior before and during morphogenetic tissue flows.
  14. The Influence of Crosslinker Architecture on Dynamic Covalent Hydrogel Viscoelasticity.
  15. Mechanical Constraints in Tumor Guide Emergent Spatial Patterns of Glioblastoma Cancer Stem Cells.
  16. In Vitro Investigation of Vocal Fold Cellular Response to Variations in Hydrogel Porosity and Elasticity.
  17. Interplay of condensate material properties and chromatin heterogeneity governs nuclear condensate ripening.
  18. PhoCoil: An Injectable and Photodegradable Single-component Recombinant Protein Hydrogel for Localized Therapeutic Cell Delivery.
  19. Effect of Peptide-Polymer Host-Guest Electrostatic Interactions on Self-Assembling Peptide Hydrogels Structural and Mechanical Properties and Polymer Diffusivity.
  20. Effects of the Biomimetic Microstructure in Electrospun Fiber Sutures and Mechanical Tension on Tissue Repair.
  21. Cancer associated fibroblast secreted miR-432-5p targets CHAC1 to inhibit ferroptosis and promote acquired chemoresistance in prostate cancer.
  22. A negative feedback loop underlies the Warburg effect.
  23. Endogenous OptoRhoGEFs reveal biophysical principles of epithelial tissue furrowing.
  24. Development of Improved Confined Compression Testing Setups for Use in Stress Relaxation Testing of Viscoelastic Biomaterials.
  25. TAZ is involved in breast cancer cell migration via regulating actin dynamics.
  26. Design approaches for 3D cell culture and 3D bioprinting platforms.
  27. Deposited footprints let cells switch between confined, oscillatory, and exploratory migration.
  28. Imaging the extracellular matrix in live tissues and organisms with a glycan-binding fluorophore.
  29. Multiscale computational model of aortic remodeling following postnatal disruption of TGFβ signaling.
  30. Focal adhesions are controlled by microtubules through local contractility regulation.
  31. Physical immune escape: Weakened mechanical communication leads to escape of metastatic colorectal carcinoma cells from macrophages.
  32. Measuring the viscoelastic relaxation function of cells with a time-dependent interpretation of the Hertz-Sneddon indentation model.
  33. Natural Hydrogels Support Kidney Organoid Generation and Promote in vitro Angiogenesis.
  34. Shp2 contributes to the regulation of nuclear shape and cellular viscoelasticity in response to substrate spatial cues.
  35. Mechanical design principles in frustrated thin elastic sheets.
  36. FRET Sensor-Modified Synthetic Hydrogels for Real-Time Monitoring of Cell-Derived Matrix Metalloproteinase Activity using Fluorescence Lifetime Imaging.
  37. Quantification of age-related changes in the structure and mechanical function of skin with multiscale imaging.
  38. Enhancing in vivo cell and tissue targeting by modulation of polymer nanoparticles and macrophage decoys.
  39. Noncontact elasticity measurement of hydrogels in a culture dish using reverberant optical coherence elastography.
  40. Growth-induced collective bending and kinetic trapping of cytoskeletal filaments.
  41. Matrix stiffening promotes chondrocyte senescence and the osteoarthritis development through downregulating HDAC3.
  42. Soft extracellular matrix drives endoplasmic reticulum stress-dependent S quiescence underlying molecular traits of pulmonary basal cells.
  43. Cationic Polysaccharides Bind to the Endothelial Cell Surface Extracellular Matrix Involving Heparan Sulfate.
  44. Cancer-associated fibroblast-derived periostin promotes papillary thyroid tumor growth through integrin-FAK-STAT3 signaling.
  45. Glycosaminoglycan-mediated lipoprotein uptake protects cancer cells from ferroptosis.
  46. Reducing Inert Materials for Optimal Cell-Cell and Cell-Matrix Interactions within Microphysiological Systems.
  47. Co-culture of STRO1 + human gingival mesenchymal stem cells and human umbilical vein endothelial cells in 3D spheroids: enhanced in vitro osteogenic and angiogenic capacities.
  48. Biomimetic Mechanically Robust Chiroptical Hydrogel Enabled by Hierarchical Bouligand Structure Engineering.
  1. IEEE J Transl Eng Health Med. 2024 ;12 413-434
    Modeling Physical Forces Experienced by Cancer and Stromal Cells Within Different Organ-Specific Tumor Tissue.
    Morgan Connaughton, Mahsa Dabagh.
      Mechanical force exerted on cancer cells by their microenvironment have been reported to drive cells toward invasive phenotypes by altering cells' motility, proliferation, and apoptosis. These mechanical forces include compressive, tensile, hydrostatic, and shear forces. The importance of forces is then hypothesized to be an alteration of cancer cells' and their microenvironment's biophysical properties as the indicator of a tumor's malignancy state. Our objective is to investigate and quantify the correlation between a tumor's malignancy state and forces experienced by the cancer cells and components of the microenvironment. In this study, we have developed a multicomponent, three-dimensional model of tumor tissue consisting of a cancer cell surrounded by fibroblasts and extracellular matrix (ECM). Our results on three different organs including breast, kidney, and pancreas show that: A) the stresses within tumor tissue are impacted by the organ specific ECM's biophysical properties, B) more invasive cancer cells experience higher stresses, C) in pancreas which has a softer ECM (Young modulus of 1.0 kPa) and stiffer cancer cells (Young modulus of 2.4 kPa and 1.7 kPa) than breast and kidney, cancer cells experienced significantly higher stresses, D) cancer cells in contact with ECM experienced higher stresses compared to cells surrounded by fibroblasts but the area of tumor stroma experiencing high stresses has a maximum length of 40 μm when the cancer cell is surrounded by fibroblasts and 12 μm for when the cancer cell is in vicinity of ECM. This study serves as an important first step in understanding of how the stresses experienced by cancer cells, fibroblasts, and ECM are associated with malignancy states of cancer cells in different organs. The quantification of forces exerted on cancer cells by different organ-specific ECM and at different stages of malignancy will help, first to develop theranostic strategies, second to predict accurately which tumors will become highly malignant, and third to establish accurate criteria controlling the progression of cancer cells malignancy. Furthermore, our in silico model of tumor tissue can yield critical, useful information for guiding ex vivo or in vitro experiments, narrowing down variables to be investigated, understanding what factors could be impacting cancer treatments or even biomarkers to be looking for.
    Keywords:  Cancer cells; ECM; cell mechanics; fibroblasts; forces on cells; malignancy; tumor microenvironment
    DOI:  https://doi.org/10.1109/JTEHM.2024.3388561
  2. J R Soc Interface. 2024 May;21(214): 20240105
    Confinement induces internal flows in adherent cell aggregates.
    M S Yousafzai, S Amiri, Z G Sun, A A Pahlavan, M Murrell.
      During mesenchymal migration, F-actin protrusion at the leading edge and actomyosin contraction determine the retrograde flow of F-actin within the lamella. The coupling of this flow to integrin-based adhesions determines the force transmitted to the extracellular matrix and the net motion of the cell. In tissues, motion may also arise from convection, driven by gradients in tissue-scale surface tensions and pressures. However, how migration coordinates with convection to determine the net motion of cellular ensembles is unclear. To explore this, we study the spreading of cell aggregates on adhesive micropatterns on compliant substrates. During spreading, a cell monolayer expands from the aggregate towards the adhesive boundary. However, cells are unable to stabilize the protrusion beyond the adhesive boundary, resulting in retraction of the protrusion and detachment of cells from the matrix. Subsequently, the cells move upwards and rearwards, yielding a bulk convective flow towards the centre of the aggregate. The process is cyclic, yielding a steady-state balance between outward (protrusive) migration along the surface, and 'retrograde' (contractile) flows above the surface. Modelling the cell aggregates as confined active droplets, we demonstrate that the interplay between surface tension-driven flows within the aggregate, radially outward monolayer flow and conservation of mass leads to an internal circulation.
    Keywords:  cell aggregates; confinement; convection; migration; surface tension; traction force
    DOI:  https://doi.org/10.1098/rsif.2024.0105
  3. Biomaterials. 2024 May 16. pii: S0142-9612(24)00148-0. [Epub ahead of print]309 122614
    Mechanical heterogeneity in a soft biomaterial niche controls BMP2 signaling.
    Erik Brauer, Aaron Herrera, Raphaela Fritsche-Guenther, Sophie Görlitz, Hans Leemhuis, Petra Knaus, Jennifer A Kirwan, Georg N Duda, Ansgar Petersen.
      The extracellular matrix is known to impact cell function during regeneration by modulating growth factor signaling. However, how the mechanical properties and structure of biomaterials can be used to optimize the cellular response to growth factors is widely neglected. Here, we engineered a macroporous biomaterial to study cellular signaling in environments that mimic the mechanical stiffness but also the mechanical heterogeneity of native extracellular matrix. We found that the mechanical interaction of cells with the heterogeneous and non-linear deformation properties of soft matrices (E < 5 kPa) enhances BMP-2 growth factor signaling with high relevance for tissue regeneration. In contrast, this effect is absent in homogeneous hydrogels that are often used to study cell responses to mechanical cues. Live cell imaging and in silico finite element modeling further revealed that a subpopulation of highly active, fast migrating cells is responsible for most of the material deformation, while a second, less active population experiences this deformation as an extrinsic mechanical stimulation. At an overall low cell density, the active cell population dominates the process, suggesting that it plays a particularly important role in early tissue healing scenarios where cells invade tissue defects or implanted biomaterials. Taken together, our findings demonstrate that the mechanical heterogeneity of the natural extracellular matrix environment plays an important role in triggering regeneration by endogenously acting growth factors. This suggests the inclusion of such mechanical complexity as a design parameter in future biomaterials, in addition to established parameters such as mechanical stiffness and stress relaxation.
    Keywords:  BMP; Biomaterials; Mechanotransduction; Stiffness; Tissue engineering
    DOI:  https://doi.org/10.1016/j.biomaterials.2024.122614
  4. Mater Today Bio. 2024 Jun;26 101077
    Heat-inducible CAR-T overcomes adverse mechanical tumor microenvironment in a 3D bioprinted glioblastoma model.
    Min Tang, Yunjia Qu, Peixiang He, Emmie Yao, Tianze Guo, Di Yu, Nancy Zhang, Wisarut Kiratitanaporn, Yazhi Sun, Longwei Liu, Yingxiao Wang, Shaochen Chen.
      Glioblastoma (GBM) presents a significant therapeutic challenge due to the limited efficacy of existing treatments. Chimeric antigen receptor (CAR) T-cell therapy offers promise, but its potential in solid tumors like GBM is undermined by the physical barrier posed by the extracellular matrix (ECM). To address the inadequacies of traditional 2D cell culture, animal models, and Matrigel-based 3D culture in mimicking the mechanical characteristics of tumor tissues, we employed biomaterials and digital light processing-based 3D bioprinting to fabricate biomimetic tumor models with finely tunable ECM stiffness independent of ECM composition. Our results demonstrated that increased material stiffness markedly impeded CAR-T cell penetration and tumor cell cytotoxicity in GBM models. The 3D bioprinted models enabled us to examine the influence of ECM stiffness on CAR-T cell therapy effectiveness, providing a clinically pertinent evaluation tool for CAR-T cell development in stiff solid tumors. Furthermore, we developed an innovative heat-inducible CAR-T cell therapy, effectively overcoming the challenges posed by the stiff tumor microenvironment.
    Keywords:  Bioprinting; CAR-T; Extracellular matrix; Solid tumor; Stiffness
    DOI:  https://doi.org/10.1016/j.mtbio.2024.101077
  5. J Vis Exp. 2024 May 03.
    Fabrication and Characterization of Colorectal Cancer Organoids from SW1222 Cell Line in Ultrashort Self-Assembling Peptide Matrix.
    Rosario Perez-Pedroza, Manola Moretti, Charlotte A E Hauser.
      Ultrashort self-assembling peptides (SAPs) can spontaneously form nanofibers that resemble the extracellular matrix. These fibers allow the formation of hydrogels that are biocompatible, biodegradable, and non-immunogenic. We have previously proven that SAPs, when biofunctionalized with protein-derived motifs, can mimic the extracellular matrix characteristics that support colorectal organoid formation. These biofunctional peptide hydrogels retain the original parent peptide's mechanical properties, tunability, and printability while incorporating cues that allow cell-matrix interactions to increase cell adhesion. This paper presents the protocols needed to evaluate and characterize the effects of various biofunctional peptide hydrogels on cell adhesion and lumen formation using an adenocarcinoma cancer cell line able to form colorectal cancer organoids cost-effectively. These protocols will help evaluate biofunctional peptide hydrogel effects on cell adhesion and luminal formation using immunostaining and fluorescence image analysis. The cell line used in this study has been previously utilized for generating organoids in animal-derived matrices.
    DOI:  https://doi.org/10.3791/66060
  6. J Control Release. 2024 May 21. pii: S0168-3659(24)00311-0. [Epub ahead of print]371 29-42
    Softening the tumor matrix through cholesterol depletion breaks the physical barrier for enhanced antitumor therapy.
    Zhangwen Peng, Yunfei Yi, Yichu Nie, Tianqi Wang, Jia Tang, Sheng Hong, Yuanqi Liu, Wenxin Huang, Shengjie Sun, Hui Tan, Meiying Wu.
      The tumor develops defense tactics, including conversing the mechanical characteristics of tumor cells and their surrounding environment. A recent study reported that cholesterol depletion stiffens tumor cells, which could enhance adaptive T-cell immunotherapy. However, it remains unclear whether reducing the cholesterol in tumor cells contributes to re-educating the stiff tumor matrix, which serves as a physical barrier against drug penetration. Herein, we found that depleting cholesterol from tumor cells can demolish the intratumor physical barrier by disrupting the mechanical signal transduction between tumor cells and the extracellular matrix through the destruction of lipid rafts. This disruption allows nanoparticles (H/S@hNP) to penetrate deeply, resulting in improved photodynamic treatment. Our research also indicates that cholesterol depletion can inhibit the epithelial-mesenchymal transition and repolarize tumor-associated macrophages from M2 to M1, demonstrating the essential role of cholesterol in tumor progression. Overall, this study reveals that a cholesterol-depleted, softened tumor matrix reduces the difficulty of drug penetration, leading to enhanced antitumor therapeutics.
    Keywords:  Cholesterol depletion; Drug penetration; Lipid raft; Tumor mechanics; Tumor stiffness
    DOI:  https://doi.org/10.1016/j.jconrel.2024.05.027
  7. Carbohydr Polym. 2024 Aug 15. pii: S0144-8617(24)00399-0. [Epub ahead of print]338 122173
    Schiff base crosslinked hyaluronic acid hydrogels with tunable and cell instructive time-dependent mechanical properties.
    Taha Behroozi Kohlan, Yanru Wen, Carina Mini, Anna Finne-Wistrand.
      The dynamic interplay between cells and their native extracellular matrix (ECM) influences cellular behavior, imposing a challenge in biomaterial design. Dynamic covalent hydrogels are viscoelastic and show self-healing ability, making them a potential scaffold for recapitulating native ECM properties. We aimed to implement kinetically and thermodynamically distinct crosslinkers to prepare self-healing dynamic hydrogels to explore the arising properties and their effects on cellular behavior. To do so, aldehyde-substituted hyaluronic acid (HA) was synthesized to generate imine, hydrazone, and oxime crosslinked dynamic covalent hydrogels. Differences in equilibrium constants of these bonds yielded distinct properties including stiffness, stress relaxation, and self-healing ability. The effects of degree of substitution (DS), polymer concentration, crosslinker to aldehyde ratio, and crosslinker functionality on hydrogel properties were evaluated. The self-healing ability of hydrogels was investigated on samples of the same and different crosslinkers and DS to obtain hydrogels with gradient properties. Subsequently, human dermal fibroblasts were cultured in 2D and 3D to assess the cellular response considering the dynamic properties of the hydrogels. Moreover, assessing cell spreading and morphology on hydrogels having similar modulus but different stress relaxation rates showed the effects of matrix viscoelasticity with higher cell spreading in slower relaxing hydrogels.
    Keywords:  Dynamic covalent hydrogel; Human dermal fibroblasts; Hyaluronic acid; Schiff base; Self-healing hydrogel; Viscoelasticity
    DOI:  https://doi.org/10.1016/j.carbpol.2024.122173
  8. Pharmaceuticals (Basel). 2024 May 16. pii: 644. [Epub ahead of print]17(5):
    Extracellular Matrix Stiffness-Induced Mechanotransduction of Capillarized Liver Sinusoidal Endothelial Cells.
    Qingjuan Wu, Quanmei Sun, Qiang Zhang, Ning Wang, Wenliang Lv, Dong Han.
      The mechanobiological response mechanism of the fenestrae of liver sinusoidal endothelial cells (LSECs) to the physical stiffness of the extracellular matrix (ECM) remains unclear. We investigated how the mechanical properties of their substrates affect the LSECs' fenestrae by the nitric oxide (NO)-dependent pathway and how they relate to the progression of hepatic sinus capillarization during liver fibrosis. We detected different stiffnesses of ECM in the progress of liver fibrosis (LF) and developed polyacrylamide hydrogel (PAM) substrates to simulate them. Softer stiffness substrates contributed to LSECs maintaining fenestrae phenotype in vitro. The stiffness of liver fibrosis tissue could be reversed in vivo via treatment with anti-ECM deposition drugs. Similarly, the capillarization of LSECs could be reversed by decreasing the ECM stiffness. Our results also indicate that the NO-dependent pathway plays a key regulatory role in the capillarization of ECM-LSECs. Our study reveals ECM-induced mechanotransduction of capillarized LSECs through a NO-dependent pathway via a previously unrevealed mechanotransduction mechanism. The elucidation of this mechanism may offer precise biomechanics-specific intervention strategies targeting liver fibrosis progression.
    Keywords:  NO-dependent pathway; biomechanics; liver fibrosis; liver sinusoidal endothelial cells
    DOI:  https://doi.org/10.3390/ph17050644
  9. Cells Tissues Organs. 2024 May 20.
    Cadherin Expression is Regulated by Mechanical Phenotypes of Fibroblasts in the Perivascular Matrix.
    Vaishali Bala, Vidhi Patel, Mary Kathryn Sewell-Loftin.
      The influence of mechanical forces generated by stromal cells in the perivascular matrix is thought to be a key regulator in controlling blood vessel growth. Cadherins are mechanosensors that facilitate and maintain cell-cell interactions and blood vessel integrity, but little is known about how stromal cells regulate cadherin signaling in the vasculature. Our objective was to investigate the relationship between mechanical phenotypes of stromal cells with cadherin expression in 3D tissue engineering models of vascular growth. Stromal cell lines were subjected to a bead displacement assay to track matrix distortions and characterize mechanical phenotypes in 3D microtissue models. These cells included human ventricular cardiac (NHCF), dermal (NHDF), lung (NHLF), breast cancer-associated (CAF), and normal breast fibroblasts (NBF). Cells were embedded in a fibrin matrix (10mg/mL) with fluorescent tracker beads; images were collected every 30min. We also studied endothelial cells (ECs) in co-culture with mechanically-active or -inactive stromal cells and quantified N-Cad, OB-Cad, and VE-Cad expression using immunofluorescence. Bead displacement studies identified mechanically-active stromal cells (CAFs, NHCFs, NHDFs) that generate matrix distortions and mechanically-inactive cells (NHLFs, NBFs). Compared to ECs only, CAFs + ECs as well as NBFs + ECs in 3D co-culture significantly decreased expression of VE-Cad; in addition, the Pearson's Correlation Coefficient for N-Cad and VE-Cad showed a strong correlation (&gt;0.7), suggesting cadherin colocalization. Using a microtissue model, we demonstrated that mechanical phenotypes associated with increased matrix deformations correspond to enhanced angiogenic growth. The results could suggest a mechanism to control tight junction regulation in developing vascular beds for tissue engineering scaffolds or understanding vascular growth during developmental processes. Our studies provide novel data for how mechanical phenotype of stromal cells in combination with secreted factor profiles is related to cadherin regulation, localization, and vascularization potential in 3D microtissue models.
    DOI:  https://doi.org/10.1159/000539319
  10. Biochem Biophys Res Commun. 2024 May 18. pii: S0006-291X(24)00678-8. [Epub ahead of print]720 150142
    Laminin I mediates resistance to lapatinib in HER2-positive brain metastatic breast cancer cells in vitro.
    Sumiran Kumar Gurung, Lalita A Shevde, Shreyas S Rao.
      The role of extracellular matrix (ECM) prevalent in the brain metastatic breast cancer (BMBC) niche in mediating cancer cell growth, survival, and response to therapeutic agents is not well understood. Emerging evidence suggests a vital role of ECM of the primary breast tumor microenvironment (TME) in tumor progression and survival. Possibly, the BMBC cells are also similarly influenced by the ECM of the metastatic niche; therefore, understanding the effect of the metastatic ECM on BMBC cells is imperative. Herein, we assessed the impact of various ECM components (i.e., Tenascin C, Laminin I, Collagen I, Collagen IV, and Fibronectin) on brain metastatic human epidermal growth factor receptor 2 (HER2)-positive and triple negative breast cancer (TNBC) cell lines in vitro. The highly aggressive TNBC cell line was minimally affected by ECM components exhibiting no remarkable changes in viability and morphology. On the contrary, amongst various ECM components tested, the HER2-positive cell line was significantly affected by Laminin I with higher viability and demonstrated a distinct spread morphology. In addition, HER2-positive BMBC cells exhibited resistance to Lapatinib in presence of Laminin I. Mechanistically, Laminin I-induced resistance to Lapatinib was mediated in part by phosphorylation of Erk 1/2 and elevated levels of Vimentin. Laminin I also significantly enhanced the migratory potential and replicative viability of HER2-positive BMBC cells. In sum, our findings show that presence of Laminin I in the TME of BMBC cells imparts resistance to targeted therapeutic agent Lapatinib, while increasing the possibility of its dispersal and clonogenic survival.
    Keywords:  Brain metastatic breast cancer; Extracellular matrix; HER2; Laminin I
    DOI:  https://doi.org/10.1016/j.bbrc.2024.150142
  11. J Neurosci Res. 2024 May;102(5): e25356
    Heterogeneity of brain extracellular matrix and astrocyte activation.
    Rebecca E Huber, Courtney Babbitt, Shelly R Peyton.
      From the blood brain barrier to the synaptic space, astrocytes provide structural, metabolic, ionic, and extracellular matrix (ECM) support across the brain. Astrocytes include a vast array of subtypes, their phenotypes and functions varying both regionally and temporally. Astrocytes' metabolic and regulatory functions poise them to be quick and sensitive responders to injury and disease in the brain as revealed by single cell sequencing. Far less is known about the influence of the local healthy and aging microenvironments on these astrocyte activation states. In this forward-looking review, we describe the known relationship between astrocytes and their local microenvironment, the remodeling of the microenvironment during disease and injury, and postulate how they may drive astrocyte activation. We suggest technology development to better understand the dynamic diversity of astrocyte activation states, and how basal and activation states depend on the ECM microenvironment. A deeper understanding of astrocyte response to stimuli in ECM-specific contexts (brain region, age, and sex of individual), paves the way to revolutionize how the field considers astrocyte-ECM interactions in brain injury and disease and opens routes to return astrocytes to a healthy quiescent state.
    Keywords:  central nervous system; glia; hyaluronan; integrin; lectican; matrix metalloproteinase; multiple sclerosis; tenascin
    DOI:  https://doi.org/10.1002/jnr.25356
  12. J Invest Dermatol. 2024 May 17. pii: S0022-202X(24)00374-9. [Epub ahead of print]
    Biomechanical activation of keloid fibroblasts promotes lysosomal remodelling and exocytosis.
    Rosie Ross, Yiyang Guo, Rebecca N Walker, Daniele Bergamaschi, Tanya J Shaw, John T Connelly.
      Keloids are a severe form of scarring for which the underlying mechanisms are poorly understood, and treatment options are limited or inconsistent. While biomechanical forces are potential drivers of keloid scarring, the direct cellular responses to mechanical cues have yet to be defined. The aim of this study was to examine the distinct responses of normal dermal fibroblasts (NDFs) and keloid-derived fibroblasts (KDFs) to changes in extracellular matrix (ECM) stiffness. When cultured on hydrogels mimicking the elasticity of normal or scarred skin, KDFs displayed greater stiffness-dependent increases in cell spreading, F-actin stress fibre formation, and focal adhesion assembly. Elevated acto-myosin contractility in KDFs disrupted the normal mechanical regulation of ECM deposition and conferred resistance myosin inhibitors. Transcriptional profiling identified mechanically-regulated pathways in NDFs and KDFs, including the actin cytoskeleton, Hippo signalling, and autophagy. Further analysis of the autophagy pathway revealed that autophagic flux was intact in both fibroblast populations and depended on acto-myosin contractility. However, KDFs displayed marked changes in lysosome organisation and an increase in lysosomal exocytosis, which was mediated by acto-myosin contractility. Together, these findings demonstrate that KDFs possess an intrinsic increase in cytoskeletal tension, which heightens the response to ECM mechanics and promotes lysosomal exocytosis.
    Keywords:  autophagy; biomechanics; cytoskeleton; lysosome; scar
    DOI:  https://doi.org/10.1016/j.jid.2024.04.015
  13. bioRxiv. 2024 May 08. pii: 2024.05.07.592778. [Epub ahead of print]
    E-cadherin tunes tissue mechanical behavior before and during morphogenetic tissue flows.
    Xun Wang, Christian M Cupo, Sassan Ostvar, Andrew D Countryman, Karen E Kasza.
      Adhesion between epithelial cells enables the remarkable mechanical behavior of epithelial tissues during morphogenesis. However, it remains unclear how cell-cell adhesion influences mechanics in static as well as in dynamically flowing epithelial tissues. Here, we systematically modulate E-cadherin-mediated adhesion in the Drosophila embryo and study the effects on the mechanical behavior of the germband epithelium before and during dramatic tissue remodeling and flow associated with body axis elongation. Before axis elongation, we find that increasing E-cadherin levels produces tissue comprising more elongated cells and predicted to be more fluid-like, providing reduced resistance to tissue flow. During axis elongation, we find that the dominant effect of E-cadherin is tuning the speed at which cells proceed through rearrangement events, revealing potential roles for E-cadherin in generating friction between cells. Before and during axis elongation, E-cadherin levels influence patterns of actomyosin-dependent forces, supporting the notion that E-cadherin tunes tissue mechanics in part through effects on actomyosin. Taken together, these findings reveal dual-and sometimes opposing-roles for E-cadherin-mediated adhesion in controlling tissue structure and dynamics in vivo that result in unexpected relationships between adhesion and flow.
    DOI:  https://doi.org/10.1101/2024.05.07.592778
  14. bioRxiv. 2024 May 10. pii: 2024.05.07.593040. [Epub ahead of print]
    The Influence of Crosslinker Architecture on Dynamic Covalent Hydrogel Viscoelasticity.
    Yung-Hao Lin, Junzhe Lou, Yan Xia, Ovijit Chaudhuri.
      Dynamic covalent crosslinked (DCC) hydrogels represent a significant advance in biomaterials for regenerative medicine and mechanobiology. These gels typically offer viscoelasticity and self-healing properties that more closely mimic in vivo tissue mechanics than traditional, predominantly elastic, covalent crosslinked hydrogels. Despite their promise, the effects of varying crosslinker architecture - side chain versus telechelic crosslinks - on the viscoelastic properties of DCC hydrogels have not been thoroughly investigated. This study introduces hydrazone-based alginate hydrogels and examines how side-chain and telechelic crosslinker architectures impact hydrogel viscoelasticity and stiffness. In side-chain crosslinked gels, higher polymer concentrations, enhances stiffness and decelerates stress relaxation, while an off-stoichiometric hydrazine-to-aldehyde ratio leads to reduced stiffness and shorter relaxation time. In telechelic crosslinked gels, maximal stiffness and stress relaxation occurs at intermediate crosslinker concentrations for both linear and star crosslinkers, with higher crosslinker valency further increasing stiffness and decreasing relaxation rates. Our result suggested different ranges of stiffness and stress relaxation are accessible with the different crosslinker architectures, with side-chain crosslinking leading to gels with slower stress relaxation times relative to the other architectures, and star crosslinked gels providing increased stiffness and slower stress relaxation relative to linear crosslinked gels. The mechanical properties of hydrogels with star crosslinking are more robust to changes induced by competing chemical reactions compared to linear crosslinking. Our research underscores the pivotal role of crosslinker architecture in defining hydrogel stiffness and viscoelasticity, providing crucial insights for the design of DCC hydrogels with tailored mechanical properties for specific biomedical applications.
    DOI:  https://doi.org/10.1101/2024.05.07.593040
  15. Mechanobiol Med. 2024 Mar;pii: 100027. [Epub ahead of print]2(1):
    Mechanical Constraints in Tumor Guide Emergent Spatial Patterns of Glioblastoma Cancer Stem Cells.
    Ngoc Luu, Shuhao Zhang, Raymond H W Lam, Weiqiang Chen.
      The mechanical constraints in the overcrowding glioblastoma (GBM) microenvironment have been implicated in the regulation of tumor heterogeneity and disease progression. Especially, such mechanical cues can alter cellular DNA transcription and give rise to a subpopulation of tumor cells called cancer stem cells (CSCs). These CSCs with stem-like properties are critical drivers of tumorigenesis, metastasis, and treatment resistance. Yet, the biophysical and molecular machinery underlying the emergence of CSCs in tumor remained unexplored. This work employed a two-dimensional micropatterned multicellular model to examine the impact of mechanical constraints arisen from geometric confinement on the emergence and spatial patterning of CSCs in GBM tumor. Our study identified distinct spatial distributions of GBM CSCs in different geometric patterns, where CSCs mostly emerged in the peripheral regions. The spatial pattern of CSCs was found to correspond to the gradients of mechanical stresses resulted from the interplay between the cell-ECM and cell-cell interactions within the confined environment. Further mechanistic study highlighted a Piezo1-RhoA-focal adhesion signaling axis in regulating GBM cell mechanosensing and the subsequent CSC phenotypic transformation. These findings provide new insights into the biophysical origin of the unique spatial pattern of CSCs in GBM tumor and offer potential avenues for targeted therapeutic interventions.
    Keywords:  Piezo1; cancer stem cell; glioblastoma; mechanotransduction; traction force
    DOI:  https://doi.org/10.1016/j.mbm.2023.100027
  16. ACS Biomater Sci Eng. 2024 May 24.
    In Vitro Investigation of Vocal Fold Cellular Response to Variations in Hydrogel Porosity and Elasticity.
    Sara Nejati, Luc Mongeau.
      Tissue regeneration is intricately influenced by the dynamic interplay between the physical attributes of tissue engineering scaffolds and the resulting biological responses. A tunable microporous hydrogel system was engineered using gelatin methacryloyl (GelMA) and polyethylene glycol diacrylate (PEGDA), with polyethylene glycol (PEG) serving as a porogen. Through systematic variation of PEGDA molecular weights, hydrogels with varying mechanical and architectural properties were obtained. The objective of the present study was to elucidate the impact of substrate mechanics and architecture on the immunological and reparative activities of vocal fold tissues. Mechanical characterization of the hydrogels was performed using tensile strength measurements and rheometry. Their morphological properties were investigated using scanning electron microscopy (SEM) and confocal microscopy. A series of biological assays were conducted. Cellular morphology, differentiation, and collagen synthesis of human vocal fold fibroblasts (hVFFs) were evaluated using immunostaining. Fibroblast proliferation was studied using the WST-1 assay, and cell migration was investigated via the Boyden chamber assay. Macrophage polarization and secretions were also examined using immunostaining and ELISA. The results revealed that increasing the molecular weight of PEGDA from 700 Da to 10,000 Da resulted in decreased hydrogel stiffness, from 62.6 to 8.8 kPa, and increased pore dimensions from approximately 64.9 to 137.4 μm. Biological evaluations revealed that hydrogels with a higher stiffness promoted fibroblast proliferation and spreading, albeit with an increased propensity for fibrosis, as indicated by a surge in myofibroblast differentiation and collagen synthesis. In contrast, hydrogels with greater molecular weights had a softer matrix with expanded pores, enhancing cellular migration and promoting an M2 macrophage phenotype conducive to tissue healing. The findings show that the hydrogels formulated with a PEGDA molecular weight of 6000 Da are best among the hydrogels considered for vocal fold repair. The microporous hydrogels could be tuned to serve in other tissue engineering applications.
    Keywords:  hydrogels; porous; tissue engineering; tunable; vocal folds
    DOI:  https://doi.org/10.1021/acsbiomaterials.4c00197
  17. bioRxiv. 2024 May 10. pii: 2024.05.07.593010. [Epub ahead of print]
    Interplay of condensate material properties and chromatin heterogeneity governs nuclear condensate ripening.
    Deb Sankar Banerjee, Tafadzwa Chigumira, Rachel M Lackner, Josiah C Kratz, David M Chenoweth, Shiladitya Banerjee, Huaiying Zhang.
      Biomolecular condensates play pivotal roles in many cellular processes, yet predicting condensate growth dynamics within the complex intracellular environment is challenging. While chromatin mechanics are known to influence condensate coarsening in the nucleus, the effect of condensate properties remains unclear. Our study demonstrates that the interplay between condensate properties and chromatin mechanics dictates condensate growth dynamics. Through chemical dimerization, we induced condensates of various properties in the cell nuclei, revealing distinct growth mechanisms: diffusion-driven or ripening-dominated. To explain experimental observations, we developed a quantitative theory that uncovers the role of chromatin in modulating condensate growth via size-dependent pressure. We find that surface tension is a critical factor in determining whether condensates undergo elastic or Ostwald ripening. Our model predicts that different condensates are affected differently by chromatin heterogeneity, validated by experimentally perturbing chromatin organization. Taken together, our work elucidates how condensate surface tension and chromatin heterogeneity govern nuclear condensate ripening.
    DOI:  https://doi.org/10.1101/2024.05.07.593010
  18. bioRxiv. 2024 May 10. pii: 2024.05.07.592971. [Epub ahead of print]
    PhoCoil: An Injectable and Photodegradable Single-component Recombinant Protein Hydrogel for Localized Therapeutic Cell Delivery.
    Nicole E Gregorio, Cole A DeForest.
      Hydrogel biomaterials offer great promise for 3D cell culture and therapeutic delivery. Despite many successes, challenges persist in that gels formed from natural proteins are only marginally tunable while those derived from synthetic polymers lack intrinsic bioinstructivity. Towards the creation of biomaterials with both excellent biocompatibility and customizability, recombinant protein-based hydrogels have emerged as molecularly defined and user-programmable platforms that mimic the proteinaceous nature of the extracellular matrix. Here, we introduce PhoCoil, a dynamically tunable recombinant hydrogel formed from a single protein component with unique multi-stimuli responsiveness. Physical crosslinking through coiled-coil interactions promotes rapid shear-thinning and self-healing behavior, rendering the gel injectable, while an included photodegradable motif affords on-demand network dissolution via visible light. PhoCoil gel photodegradation can be spatiotemporally and lithographically controlled in a dose-dependent manner, through complex tissue, and without harm to encapsulated cells. We anticipate that PhoCoil will enable new applications in tissue engineering and regenerative medicine.
    DOI:  https://doi.org/10.1101/2024.05.07.592971
  19. Biomacromolecules. 2024 May 21.
    Effect of Peptide-Polymer Host-Guest Electrostatic Interactions on Self-Assembling Peptide Hydrogels Structural and Mechanical Properties and Polymer Diffusivity.
    Siyuan Dong, Sam L Chapman, Alain Pluen, Stephen M Richardson, Aline F Miller, Alberto Saiani.
      Peptide-based supramolecular hydrogels are an attractive class of soft materials for biomedical applications when biocompatibility is a key requirement as they exploit the physical self-assembly of short self-assembling peptides avoiding the need for chemical cross-linking. Based on the knowledge developed through our previous work, we designed two novel peptides, E(FKFE)2 and K(FEFK)2, that form transparent hydrogels at pH 7. We characterized the phase behavior of these peptides and showed the clear link that exists between the charge carried by the peptides and the physical state of the samples. We subsequently demonstrate the cytocompatibility of the hydrogel and its suitability for 3D cell culture using 3T3 fibroblasts and human mesenchymal stem cells. We then loaded the hydrogels with two polymers, poly-l-lysine and dextran. When polymer and peptide fibers carry opposite charges, the size of the elemental fibril formed decreases, while the overall level of fiber aggregation and fiber bundle formation increases. This overall network topology change, and increase in cross-link stability and density, leads to an overall increase in the hydrogel mechanical properties and stability, i.e., resistance to swelling when placed in excess media. Finally, we investigate the diffusion of the polymers out of the hydrogels and show how electrostatic interactions can be used to control the release of large molecules. The work clearly shows how polymers can be used to tailor the properties of peptide hydrogels through guided intermolecular interactions and demonstrates the potential of these new soft hydrogels for use in the biomedical field in particular for delivery or large molecular payloads and cells as well as scaffolds for 3D cell culture.
    DOI:  https://doi.org/10.1021/acs.biomac.4c00232
  20. ACS Appl Mater Interfaces. 2024 May 24.
    Effects of the Biomimetic Microstructure in Electrospun Fiber Sutures and Mechanical Tension on Tissue Repair.
    Jie Dang, Shifen Huang, Shengmei Li, Jingyao Liu, Zibo Chen, Liu Wang, Jie Wang, Hao Chen, Shanshan Xu.
      Electrospun microfibers, designed to emulate the extracellular matrix (ECM), play a crucial role in regulating the cellular microenvironment for tissue repair. Understanding their mechanical influence and inherent biological interactions at the ECM interface, however, remains a complex challenge. This study delves into the role of mechanical cues in tissue repair by fabricating Col/PLCL microfibers with varying chemical compositions and alignments that mimic the structure of the ECM. Furthermore, we optimized these microfibers to create the Col/PLCL@PDO aligned suture, with a specific emphasis on mechanical tension in tissue repair. The result reveals that within fibers of identical chemical composition, fibroblast proliferation is more pronounced in aligned fibers than in unaligned ones. Moreover, cells on aligned fibers exhibit an increased aspect ratio. In vivo experiments demonstrated that as the tension increased to a certain level, cell proliferation augmented, cells assumed more elongated morphologies with distinct protrusions, and there was an elevated secretion of collagen III and tension suture, facilitating soft tissue repair. This research illuminates the structural and mechanical dynamics of electrospun fiber scaffolds; it will provide crucial insights for the advancement of precise and controllable tissue engineering materials.
    Keywords:  Col/PLCL@PDO scaffolds; aligned microfibers; mechanical microenvironment; tension suture; tissue repair
    DOI:  https://doi.org/10.1021/acsami.4c01478
  21. Oncogene. 2024 May 20.
    Cancer associated fibroblast secreted miR-432-5p targets CHAC1 to inhibit ferroptosis and promote acquired chemoresistance in prostate cancer.
    Jun Zhao, Jijie Shen, Liang Mao, Tianli Yang, Jingyu Liu, Sun Hongbin.
      Prostate cancer (PCa) ranks as the sixth most serious male malignant disease globally. While docetaxel (DTX) chemotherapy is the standard treatment for advanced PCa patients with distant metastasis, some individuals exhibit insensitivity or resistance to DTX. Cancer-associated fibroblasts (CAFs) play a pivotal role as stromal cells within the tumor microenvironment, influencing tumor development, progression, and drug resistance through exosomes. Ferroptosis, a novel form of programmed cell death, is characterized by intracellular iron accumulation that triggers lipid peroxidation, ultimately leading to cell demise. To delve into the potential mechanisms of chemotherapy resistance in prostate cancer, our research delved into the impact of CAF-derived exosomes on ferroptosis. Our findings revealed that CAF exosomes hindered the buildup of lipid reactive oxygen species (ROS) in prostate cancer cells induced by erastin, as well as mitigated erastin-induced mitochondrial damage, thereby impeding iron-induced cell death in prostate cancer cells. Furthermore, miR-432-5p was identified to diminish glutathione (GSH) consumption by targeting CHAC1, consequently inhibiting ferroptosis in prostate cancer cells. Our study found that miR-432-5p, originating from cancer-associated fibroblast (CAF) exosomes, suppresses ferroptosis by targeting CHAC1, thereby increasing resistance to docetaxel (DTX) in PCa. This research introduces a novel approach to address resistance to DTX.
    DOI:  https://doi.org/10.1038/s41388-024-03057-6
  22. NPJ Syst Biol Appl. 2024 May 24. 10(1): 55
    A negative feedback loop underlies the Warburg effect.
    Alok Jaiswal, Raghvendra Singh.
      Aerobic glycolysis, or the Warburg effect, is used by cancer cells for proliferation while producing lactate. Although lactate production has wide implications for cancer progression, it is not known how this effect increases cell proliferation and relates to oxidative phosphorylation. Here, we elucidate that a negative feedback loop (NFL) is responsible for the Warburg effect. Further, we show that aerobic glycolysis works as an amplifier of oxidative phosphorylation. On the other hand, quiescence is an important property of cancer stem cells. Based on the NFL, we show that both aerobic glycolysis and oxidative phosphorylation, playing a synergistic role, are required to achieve cell quiescence. Further, our results suggest that the cells in their hypoxic niche are highly proliferative yet close to attaining quiescence by increasing their NADH/NAD+ ratio through the severity of hypoxia. The findings of this study can help in a better understanding of the link among metabolism, cell cycle, carcinogenesis, and stemness.
    DOI:  https://doi.org/10.1038/s41540-024-00377-x
  23. bioRxiv. 2024 May 12. pii: 2024.05.12.593711. [Epub ahead of print]
    Endogenous OptoRhoGEFs reveal biophysical principles of epithelial tissue furrowing.
    Andrew D Countryman, Caroline A Doherty, R Marisol Herrera-Perez, Karen E Kasza.
      During development, epithelia function as malleable substrates that undergo extensive remodeling to shape developing embryos. Optogenetic control of Rho signaling provides an avenue to investigate the mechanisms of epithelial morphogenesis, but transgenic optogenetic tools can be limited by variability in tool expression levels and deleterious effects of transgenic overexpression on development. Here, we use CRISPR/Cas9 to tag Drosophila RhoGEF2 and Cysts/Dp114RhoGEF with components of the iLID/SspB optogenetic heterodimer, permitting light-dependent control over endogenous protein activities. Using quantitative optogenetic perturbations, we uncover a dose-dependence of tissue furrow depth and bending behavior on RhoGEF recruitment, revealing mechanisms by which developing embryos can shape tissues into particular morphologies. We show that at the onset of gastrulation, furrows formed by cell lateral contraction are oriented and size-constrained by a stiff basal actomyosin layer. Our findings demonstrate the use of quantitative, 3D-patterned perturbations of cell contractility to precisely shape tissue structures and interrogate developmental mechanics.
    DOI:  https://doi.org/10.1101/2024.05.12.593711
  24. Gels. 2024 May 13. pii: 329. [Epub ahead of print]10(5):
    Development of Improved Confined Compression Testing Setups for Use in Stress Relaxation Testing of Viscoelastic Biomaterials.
    Anthony El Kommos, Alicia R Jackson, Fotios Andreopoulos, Francesco Travascio.
      The development of cell-based biomaterial alternatives holds significant promise in tissue engineering applications, but it requires accurate mechanical assessment. Herein, we present the development of a novel 3D-printed confined compression apparatus, fabricated using clear resin, designed to cater to the unique demands of biomaterial developers. Our objective was to enhance the precision of force measurements and improve sample visibility during compression testing. We compared the performance of our innovative 3D-printed confined compression setup to a conventional setup by performing stress relaxation testing on hydrogels with variable degrees of crosslinking. We assessed equilibrium force, aggregate modulus, and peak force. This study demonstrates that our revised setup can capture a larger range of force values while simultaneously improving accuracy. We were able to detect significant differences in force and aggregate modulus measurements of hydrogels with variable degrees of crosslinking using our revised setup, whereas these were indistinguishable with the convectional apparatus. Further, by incorporating a clear resin in the fabrication of the compression chamber, we improved sample visibility, thus enabling real-time monitoring and informed assessment of biomaterial behavior under compressive testing.
    Keywords:  aggregate modulus; confined compression; equilibrium force; hydrogel; peak force
    DOI:  https://doi.org/10.3390/gels10050329
  25. Front Oncol. 2024 ;14 1376831
    TAZ is involved in breast cancer cell migration via regulating actin dynamics.
    Hong Seok Choi, Hyo-Ju Jang, Mathilde K Kristensen, Tae-Hwan Kwon.
       Background: Cancer metastasis is dependent on cell migration. Several mechanisms, including epithelial-to-mesenchymal transition (EMT) and actin fiber formation, could be involved in cancer cell migration. As a downstream effector of the Hippo signaling pathway, transcriptional coactivator with PDZ-binding motif (TAZ) is recognized as a key mediator of the metastatic ability of breast cancer cells. We aimed to examine whether TAZ affects the migration of breast cancer cells through the regulation of EMT or actin cytoskeleton.
    Methods: MCF-7 and MDA-MB-231 cells were treated with siRNA to attenuate TAZ abundance. Transwell migration assay and scratch wound healing assay were performed to study the effects of TAZ knockdown on cancer cell migration. Fluorescence microscopy was conducted to examine the vinculin and phalloidin. Semiquantitative immunoblotting and quantitative real-time PCR were performed to study the expression of small GTPases and kinases. Changes in the expression of genes associated with cell migration were examined through next-generation sequencing.
    Results: TAZ-siRNA treatment reduced TAZ abundance in MCF-7 and MDA-MB-231 breast cancer cells, which was associated with a significant decrease in cell migration. TAZ knockdown increased the expression of fibronectin, but it did not exhibit the typical pattern of EMT progression. TGF-β treatment in MDA-MB-231 cells resulted in a reduction in TAZ and an increase in fibronectin levels. However, it paradoxically promoted cell migration, suggesting that EMT is unlikely to be involved in the decreased migration of breast cancer cells in response to TAZ suppression. RhoA, a small Rho GTPase protein, was significantly reduced in response to TAZ knockdown. This caused a decrease in the expression of the Rho-dependent downstream pathway, i.e., LIM kinase 1 (LIMK1), phosphorylated LIMK1/2, and phosphorylated cofilin, leading to actin depolymerization. Furthermore, myosin light chain kinase (MLCK) and phosphorylated MLC2 were significantly decreased in MDA-MB-231 cells with TAZ knockdown, inhibiting the assembly of stress fibers and focal adhesions.
    Conclusion: TAZ knockdown inhibits the migration of breast cancer cells by regulating the intracellular actin cytoskeletal organization. This is achieved, in part, by reducing the abundance of RhoA and Rho-dependent downstream kinase proteins, which results in actin depolymerization and the disassembly of stress fibers and focal adhesions.
    Keywords:  TAZ; actin; breast cancer; cell migration; small GTPase
    DOI:  https://doi.org/10.3389/fonc.2024.1376831
  26. Biophys Rev (Melville). 2024 Jun;5(2): 021304
    Design approaches for 3D cell culture and 3D bioprinting platforms.
    M Sreepadmanabh, Ashitha B Arun, Tapomoy Bhattacharjee.
      The natural habitat of most cells consists of complex and disordered 3D microenvironments with spatiotemporally dynamic material properties. However, prevalent methods of in vitro culture study cells under poorly biomimetic 2D confinement or homogeneous conditions that often neglect critical topographical cues and mechanical stimuli. It has also become increasingly apparent that cells in a 3D conformation exhibit dramatically altered morphological and phenotypical states. In response, efforts toward designing biomaterial platforms for 3D cell culture have taken centerstage over the past few decades. Herein, we present a broad overview of biomaterials for 3D cell culture and 3D bioprinting, spanning both monolithic and granular systems. We first critically evaluate conventional monolithic hydrogel networks, with an emphasis on specific experimental requirements. Building on this, we document the recent emergence of microgel-based 3D growth media as a promising biomaterial platform enabling interrogation of cells within porous and granular scaffolds. We also explore how jammed microgel systems have been leveraged to spatially design and manipulate cellular structures using 3D bioprinting. The advent of these techniques heralds an unprecedented ability to experimentally model complex physiological niches, with important implications for tissue bioengineering and biomedical applications.
    DOI:  https://doi.org/10.1063/5.0188268
  27. Proc Natl Acad Sci U S A. 2024 May 28. 121(22): e2318248121
    Deposited footprints let cells switch between confined, oscillatory, and exploratory migration.
    Emiliano Perez Ipiña, Joseph d'Alessandro, Benoît Ladoux, Brian A Camley.
      For eukaryotic cells to heal wounds, respond to immune signals, or metastasize, they must migrate, often by adhering to extracellular matrix (ECM). Cells may also deposit ECM components, leaving behind a footprint that influences their crawling. Recent experiments showed that some epithelial cell lines on micropatterned adhesive stripes move persistently in regions they have previously crawled over, where footprints have been formed, but barely advance into unexplored regions, creating an oscillatory migration of increasing amplitude. Here, we explore through mathematical modeling how footprint deposition and cell responses to footprint combine to allow cells to develop oscillation and other complex migratory motions. We simulate cell crawling with a phase field model coupled to a biochemical model of cell polarity, assuming local contact with the deposited footprint activates Rac1, a protein that establishes the cell's front. Depending on footprint deposition rate and response to the footprint, cells on micropatterned lines can display many types of motility, including confined, oscillatory, and persistent motion. On two-dimensional (2D) substrates, we predict a transition between cells undergoing circular motion and cells developing an exploratory phenotype. Small quantitative changes in a cell's interaction with its footprint can completely alter exploration, allowing cells to tightly regulate their motion, leading to different motility phenotypes (confined vs. exploratory) in different cells when deposition or sensing is variable from cell to cell. Consistent with our computational predictions, we find in earlier experimental data evidence of cells undergoing both circular and exploratory motion.
    Keywords:  Rho GTPases; cell motility; footprint; random walks
    DOI:  https://doi.org/10.1073/pnas.2318248121
  28. bioRxiv. 2024 May 10. pii: 2024.05.09.593460. [Epub ahead of print]
    Imaging the extracellular matrix in live tissues and organisms with a glycan-binding fluorophore.
    Antonio Fiore, Guoqiang Yu, Jason J Northey, Ronak Patel, Thomas A Ravenscroft, Richard Ikegami, Wiert Kolkman, Pratik Kumar, Jonathan B Grimm, Tanya L Dilan, Virginia M S Ruetten, Misha B Ahrens, Hari Shroff, Luke D Lavis, Shaohe Wang, Valerie M Weaver, Kayvon Pedram.
      All multicellular systems produce and dynamically regulate extracellular matrices (ECM) that play important roles in both biochemical and mechanical signaling. Though the spatial arrangement of these extracellular assemblies is critical to their biological functions, visualization of ECM structure is challenging, in part because the biomolecules that compose the ECM are difficult to fluorescently label individually and collectively. Here, we present a cell-impermeable small molecule fluorophore, termed Rhobo6, that turns on and red shifts upon reversible binding to glycans. Given that most ECM components are densely glycosylated, the dye enables wash-free visualization of ECM, in systems ranging from in vitro substrates to in vivo mouse mammary tumors. Relative to existing techniques, Rhobo6 provides a broad substrate profile, superior tissue penetration, nonperturbative labeling, and negligible photobleaching. This work establishes a straightforward method for imaging the distribution of ECM in live tissues and organisms, lowering barriers for investigation of extracellular biology.
    DOI:  https://doi.org/10.1101/2024.05.09.593460
  29. J Biomech. 2024 May 15. pii: S0021-9290(24)00230-6. [Epub ahead of print] 112152
    Multiscale computational model of aortic remodeling following postnatal disruption of TGFβ signaling.
    Ana C Estrada, Linda Irons, George Tellides, Jay D Humphrey.
      The healthy adult aorta is a remarkably resilient structure, able to resist relentless cardiac-induced and hemodynamic loads under normal conditions. Fundamental to such mechanical homeostasis is the mechano-sensitive cell signaling that controls gene products and thus the structural integrity of the wall. Mouse models have shown that smooth muscle cell-specific disruption of transforming growth factor-beta (TGFβ) signaling during postnatal development compromises this resiliency, rendering the aortic wall susceptible to aneurysm and dissection under normal mechanical loading. By contrast, disruption of such signaling in the adult aorta appears to introduce a vulnerability that remains hidden under normal loading, but manifests under increased loading as experienced during hypertension. We present a multiscale (transcript to tissue) computational model to examine possible reasons for compromised mechanical homeostasis in the adult aorta following reduced TGFβ signaling in smooth muscle cells.
    Keywords:  Aorta; Biomechanics; Cell signaling; Hypertension; Logic-based; Transforming growth factor
    DOI:  https://doi.org/10.1016/j.jbiomech.2024.112152
  30. EMBO J. 2024 May 20.
    Focal adhesions are controlled by microtubules through local contractility regulation.
    Julien Aureille, Srinivas S Prabhu, Sam F Barnett, Aaron J Farrugia, Isabelle Arnal, Laurence Lafanechère, Boon Chuan Low, Pakorn Kanchanawong, Alex Mogilner, Alexander D Bershadsky.
      Microtubules regulate cell polarity and migration via local activation of focal adhesion turnover, but the mechanism of this process is insufficiently understood. Molecular complexes containing KANK family proteins connect microtubules with talin, the major component of focal adhesions. Here, local optogenetic activation of KANK1-mediated microtubule/talin linkage promoted microtubule targeting to an individual focal adhesion and subsequent withdrawal, resulting in focal adhesion centripetal sliding and rapid disassembly. This sliding is preceded by a local increase of traction force due to accumulation of myosin-II and actin in the proximity of the focal adhesion. Knockdown of the Rho activator GEF-H1 prevented development of traction force and abolished sliding and disassembly of focal adhesions upon KANK1 activation. Other players participating in microtubule-driven, KANK-dependent focal adhesion disassembly include kinases ROCK, PAK, and FAK, as well as microtubules/focal adhesion-associated proteins kinesin-1, APC, and αTAT. Based on these data, we develop a mathematical model for a microtubule-driven focal adhesion disruption involving local GEF-H1/RhoA/ROCK-dependent activation of contractility, which is consistent with experimental data.
    Keywords:  Focal Adhesion Mechanosensitivity; GEF-H1; KANK1; Myosin-II; iLID Optogenetics
    DOI:  https://doi.org/10.1038/s44318-024-00114-4
  31. Proc Natl Acad Sci U S A. 2024 May 28. 121(22): e2322479121
    Physical immune escape: Weakened mechanical communication leads to escape of metastatic colorectal carcinoma cells from macrophages.
    Chen Yang, Xinrui Dong, Bingrui Sun, Ting Cao, Ruipei Xie, Yiyu Zhang, Ziyue Yang, Jing Huang, Ying Lu, Ming Li, Xiaochen Wang, Ye Xu, Fangfu Ye, Qihui Fan.
      The significance of biochemical cues in the tumor immune microenvironment in affecting cancer metastasis is well established, but the role of physical factors in the microenvironment remains largely unexplored. In this article, we investigated how the mechanical interaction between cancer cells and immune cells, mediated by extracellular matrix (ECM), influences immune escape of cancer cells. We focus on the mechanical regulation of macrophages' targeting ability on two distinct types of colorectal carcinoma (CRC) cells with different metastatic potentials. Our results show that macrophages can effectively target CRC cells with low metastatic potential, due to the strong contraction exhibited by the cancer cells on the ECM, and that cancer cells with high metastatic potential demonstrated weakened contractions on the ECM and can thus evade macrophage attack to achieve immune escape. Our findings regarding the intricate mechanical interactions between immune cells and cancer cells can serve as a crucial reference for further exploration of cancer immunotherapy strategies.
    Keywords:  extracellular matrix; immune escape; mechanical signals
    DOI:  https://doi.org/10.1073/pnas.2322479121
  32. Heliyon. 2024 May 30. 10(10): e30623
    Measuring the viscoelastic relaxation function of cells with a time-dependent interpretation of the Hertz-Sneddon indentation model.
    I V M Lima, A V S Silva, F D Sousa, W P Ferreira, R S Freire, C L N de Oliveira, J S de Sousa.
      The Hertz-Sneddon elastic indentation model is widely adopted in the biomechanical investigation of living cells and other soft materials using atomic force microscopy despite the explicit viscoelastic nature of these materials. In this work, we demonstrate that an exact analytical viscoelastic force model for power-law materials, can be interpreted as a time-dependent Hertz-Sneddon-like model. Characterizing fibroblasts (L929) and osteoblasts (OFCOLII) demonstrates the model's accuracy. Our results show that the difference between Young's modulus EY obtained by fitting force curves with the Hertz-Sneddon model and the effective Young's modulus derived from the viscoelastic force model is less than 3%, even when cells are probed at large forces where nonlinear deformation effects become significant. We also propose a measurement protocol that involves probing samples at different indentation speeds and forces, enabling the construction of the average viscoelastic relaxation function of samples by conveniently fitting the force curves with the Hertz-Sneddon model.
    Keywords:  Atomic force microscopy; Cell viscoelasticity; Hertz-Sneddon contact model; Viscoelastic force model
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e30623
  33. Adv Mater. 2024 May 19. e2400306
    Natural Hydrogels Support Kidney Organoid Generation and Promote in vitro Angiogenesis.
    Elena Garreta, Daniel Moya-Rull, Andrés Marco, Gaia Amato, Asier Ullate-Agote, Carolina Tarantino, Maria Gallo, David Esporrín-Ubieto, Alberto Centeno, Amaia Vilas-Zornoza, Rafael Mestre, María Kalil, Izar Gorroñogoitia, Ane Miren Zaldua, Samuel Sanchez, Laura Izquierdo Reyes, M Eugenia Fernández-Santos, Felipe Prosper, Nuria Montserrat.
      To date strategies aiming to modulate cell to extracellular matrix (ECM) interactions during organoid derivation remain largely unexplored. Here renal decellularized extracellular matrix (dECM) hydrogels are fabricated from porcine and human renal cortex as biomaterials to enrich cell-to-ECM crosstalk during the onset of kidney organoid differentiation from human pluripotent stem cells (hPSCs). Renal dECM-derived hydrogels are used in combination with hPSC-derived renal progenitor cells to define new approaches for 2D and 3D kidney organoid differentiation, demonstrating that in the presence of these biomaterials the resulting kidney organoids exhibit renal differentiation features, and the formation of an endogenous vascular component. Based on these observations, a new method to produce kidney organoids with vascular-like structures is achieved through the assembly of hPSC-derived endothelial-like organoids with kidney organoids in 3D. Major readouts of kidney differentiation and renal cell morphology are assessed exploiting these culture platforms as new models of nephrogenesis. Overall, this work shows that exploiting cell-to-ECM interactions during the onset of kidney differentiation from hPSCs facilitates and optimizes current approaches for kidney organoid derivation thereby increasing the utility of these unique culture cell platforms for personalized medicine. This article is protected by copyright. All rights reserved.
    Keywords:  assembloids; extracellular matrix derived hydrogels; human pluripotent stem cells; kidney organoids; vascularization
    DOI:  https://doi.org/10.1002/adma.202400306
  34. Biochem Biophys Res Commun. 2024 May 18. pii: S0006-291X(24)00680-6. [Epub ahead of print]721 150144
    Shp2 contributes to the regulation of nuclear shape and cellular viscoelasticity in response to substrate spatial cues.
    Yin-Quan Chen, Hsin-Chang Lee, Hsiao-Hui Lee.
      Cell polarization can be guided by substrate topology through space constraints and adhesion induction, which are part of cellular mechanosensing pathways. Here, we demonstrated that protein tyrosine phosphatase Shp2 plays a crucial role in mediating the response of cells to substrate spatial cues. When compared to cells spreading on surfaces coated uniformly with fibronectin (FN), cells attached to 10 μm-width FN-strip micropattern (MP), which provides spatial cues for uniaxial spreading, exhibited elongated focal adhesions (FAs) and aligned stress fibers in the direction of the MP. As a result of uniaxial cell spreading, nuclei became elongated, dependent on ROCK-mediated actomyosin contractility. Additionally, intracellular viscoelasticity also increased. Shp2-deficient cells did not display elongated FAs mediated by MP, well-aligned stress fibers, or changes in nuclear shape and intracellular viscoelasticity. Overall, our data suggest that Shp2 is involved in regulating FAs and the actin cytoskeleton to modulate nuclear shape and intracellular physical properties in response to substrate spatial cues.
    Keywords:  Focal adhesion; Micropattern; Nuclear shape; Viscoelasticity
    DOI:  https://doi.org/10.1016/j.bbrc.2024.150144
  35. Soft Matter. 2024 May 20.
    Mechanical design principles in frustrated thin elastic sheets.
    Michal Arieli, Michael Moshe, Eran Sharon.
      Using a geometric formalism of elasticity theory we develop a systematic theoretical framework for shaping and manipulating the energy landscape of slender solids, and consequently their mechanical response to external perturbations. We formally express global mechanical properties associated with non-Euclidean thin sheets in terms of their local rest lengths and rest curvatures, and we interpret the expressions as both forward and inverse problems for designing the desired mechanical properties. We show that by wisely designing geometric frustration, anomalous mechanical properties can be encoded into a material using accessible experimental techniques. To test the methodology we derive a family of ribbon-springs with extreme mechanical behavior such as tunable, anharmonic, and even vanishing rigidities. The presented formalism can be discretized, offering a new methodology for designing mechanical properties and thus opens a new pathway for the design of both continuum and discrete solids and structures.
    DOI:  https://doi.org/10.1039/d4sm00166d
  36. Adv Funct Mater. 2024 May;pii: adfm.202309711. [Epub ahead of print]34(21):
    FRET Sensor-Modified Synthetic Hydrogels for Real-Time Monitoring of Cell-Derived Matrix Metalloproteinase Activity using Fluorescence Lifetime Imaging.
    Ziqian Yan, Thomas Kavanagh, Ricardo da Silva Harrabi, Suzette T Lust, Chunling Tang, Rebecca Beavil, Manuel M Müller, Andrew Beavil, Simon Ameer-Beg, Ricardo M P da Silva, Eileen Gentleman.
      Matrix remodeling plays central roles in a range of physiological and pathological processes and is driven predominantly by the activity of matrix metalloproteinases (MMPs), which degrade extracellular matrix (ECM) proteins. Our understanding of how MMPs regulate cell and tissue dynamics is often incomplete as in vivo approaches are lacking and many in vitro strategies cannot provide high-resolution, quantitative measures of enzyme activity in situ within tissue-like 3D microenvironments. Here, we incorporate a Förster resonance energy transfer (FRET) sensor of MMP activity into fully synthetic hydrogels that mimic many properties of the native ECM. We then use fluorescence lifetime imaging to provide a real-time, fluorophore concentration-independent quantification of MMP activity, establishing a highly accurate, readily adaptable platform for studying MMP dynamics in situ. MCF7 human breast cancer cells encapsulated within hydrogels highlight the detection of MMP activity both locally, at the sub-micron level, and within the bulk hydrogel. Our versatile platform may find use in a range of biological studies to explore questions in the dynamics of cancer metastasis, development, and tissue repair by providing high-resolution, quantitative and in situ readouts of local MMP activity within native tissue-like environments.
    Keywords:  FRET sensor; Matrix metalloproteinase; hydrogel; matrix remodeling
    DOI:  https://doi.org/10.1002/adfm.202309711
  37. Geroscience. 2024 May 18.
    Quantification of age-related changes in the structure and mechanical function of skin with multiscale imaging.
    Alan E Woessner, Nathan J Witt, Jake D Jones, Edward A Sander, Kyle P Quinn.
      The mechanical properties of skin change during aging but the relationships between structure and mechanical function remain poorly understood. Previous work has shown that young skin exhibits a substantial decrease in tissue volume, a large macro-scale Poisson's ratio, and an increase in micro-scale collagen fiber alignment during mechanical stretch. In this study, label-free multiphoton microscopy was used to quantify how the microstructure and fiber kinematics of aged mouse skin affect its mechanical function. In an unloaded state, aged skin was found to have less collagen alignment and more non-enzymatic collagen fiber crosslinks. Skin samples were then loaded in uniaxial tension and aged skin exhibited a lower mechanical stiffness compared to young skin. Aged tissue also demonstrated less volume reduction and a lower macro-scale Poisson's ratio at 10% uniaxial strain, but not at 20% strain. The magnitude of 3D fiber realignment in the direction of loading was not different between age groups, and the amount of realignment in young and aged skin was less than expected based on theoretical fiber kinematics affine to the local deformation. These findings provide key insights on how the collagen fiber microstructure changes with age, and how those changes affect the mechanical function of skin, findings which may help guide wound healing or anti-aging treatments.
    Keywords:  Biomechanics; Intrinsic Aging; Multi-scale; Multiphoton Microscopy; Second Harmonic Generation; Skin
    DOI:  https://doi.org/10.1007/s11357-024-01199-9
  38. Nat Commun. 2024 May 18. 15(1): 4247
    Enhancing in vivo cell and tissue targeting by modulation of polymer nanoparticles and macrophage decoys.
    Alexandra S Piotrowski-Daspit, Laura G Bracaglia, David A Eaton, Owen Richfield, Thomas C Binns, Claire Albert, Jared Gould, Ryland D Mortlock, Marie E Egan, Jordan S Pober, W Mark Saltzman.
      The in vivo efficacy of polymeric nanoparticles (NPs) is dependent on their pharmacokinetics, including time in circulation and tissue tropism. Here we explore the structure-function relationships guiding physiological fate of a library of poly(amine-co-ester) (PACE) NPs with different compositions and surface properties. We find that circulation half-life as well as tissue and cell-type tropism is dependent on polymer chemistry, vehicle characteristics, dosing, and strategic co-administration of distribution modifiers, suggesting that physiological fate can be optimized by adjusting these parameters. Our high-throughput quantitative microscopy-based platform to measure the concentration of nanomedicines in the blood combined with detailed biodistribution assessments and pharmacokinetic modeling provides valuable insight into the dynamic in vivo behavior of these polymer NPs. Our results suggest that PACE NPs-and perhaps other NPs-can be designed with tunable properties to achieve desired tissue tropism for the in vivo delivery of nucleic acid therapeutics. These findings can guide the rational design of more effective nucleic acid delivery vehicles for in vivo applications.
    DOI:  https://doi.org/10.1038/s41467-024-48442-7
  39. J Biomech. 2024 May 16. pii: S0021-9290(24)00232-X. [Epub ahead of print]169 112154
    Noncontact elasticity measurement of hydrogels in a culture dish using reverberant optical coherence elastography.
    Hao Xu, Fanlei Yang, Ting Liang, Zong-Ping Luo.
      Estimating the elasticity of hydrogel phantoms in a cell culture plane is important for understanding the cell behavior in response to various types of mechanical stimuli. Hence, a noncontact tool for measuring the elastic properties of hydrogel phantoms in such three-dimensional cell cultures is required. A well-known method to determine the mechanical properties of hydrogels is the transient wave method. However, due to the multiple reflections of waves from the boundaries, a bigger cell culture plane or multiple directional filters may be required. In this study, we utilized reverberant shear wave elastography, which is based on the autocorrelation principle, to evaluate the shear wave speed in hydrogel samples within a culture dish. Numerical simulations were performed first to confirm the validity of the reverberant elastography method. Subsequently, we used this method to measure the wave speeds in hydrogel phantoms with different concentrations. Shear rheology tests were also performed, and their results were found to be in good agreement with the measured shear wave speeds. The proposed method could be useful for measuring the elasticity of tissues in tissue engineering applications in an inexpensive and noncontact manner.
    Keywords:  Cell culture dish; Hydrogel; Noncontact elasticity measurement; Optical coherence elastography; Reverberant shear wave elastography; Tissue engineering
    DOI:  https://doi.org/10.1016/j.jbiomech.2024.112154
  40. Cytoskeleton (Hoboken). 2024 May 22.
    Growth-induced collective bending and kinetic trapping of cytoskeletal filaments.
    Deb Sankar Banerjee, Simon L Freedman, Michael P Murrell, Shiladitya Banerjee.
      Growth and turnover of actin filaments play a crucial role in the construction and maintenance of actin networks within cells. Actin filament growth occurs within limited space and finite subunit resources in the actin cortex. To understand how filament growth shapes the emergent architecture of actin networks, we developed a minimal agent-based model coupling filament mechanics and growth in a limiting subunit pool. We find that rapid filament growth induces kinetic trapping of highly bent actin filaments. Such collective bending patterns are long-lived, organized around nematic defects, and arise from competition between filament polymerization and bending elasticity. The stability of nematic defects and the extent of kinetic trapping are amplified by an increase in the abundance of the actin pool and by crosslinking the network. These findings suggest that kinetic trapping is a robust consequence of growth in crowded environments, providing a route to program shape memory in actin networks.
    Keywords:  actin network assembly; agent‐based modeling; filament growth; kinetic trapping; topological defects
    DOI:  https://doi.org/10.1002/cm.21877
  41. Bone Res. 2024 May 24. 12(1): 32
    Matrix stiffening promotes chondrocyte senescence and the osteoarthritis development through downregulating HDAC3.
    Bowen Fu, Jianlin Shen, Xuenong Zou, Nian Sun, Ze Zhang, Zengping Liu, Canjun Zeng, Huan Liu, Wenhua Huang.
      Extracellular matrix (ECM) stiffening is a typical characteristic of cartilage aging, which is a quintessential feature of knee osteoarthritis (KOA). However, little is known about how ECM stiffening affects chondrocytes and other molecules downstream. This study mimicked the physiological and pathological stiffness of human cartilage using polydimethylsiloxane (PDMS) substrates. It demonstrated that epigenetic Parkin regulation by histone deacetylase 3 (HDAC3) represents a new mechanosensitive mechanism by which the stiffness matrix affected chondrocyte physiology. We found that ECM stiffening accelerated cultured chondrocyte senescence in vitro, while the stiffness ECM downregulated HDAC3, prompting Parkin acetylation to activate excessive mitophagy and accelerating chondrocyte senescence and osteoarthritis (OA) in mice. Contrarily, intra-articular injection with an HDAC3-expressing adeno-associated virus restored the young phenotype of the aged chondrocytes stimulated by ECM stiffening and alleviated OA in mice. The findings indicated that changes in the mechanical ECM properties initiated pathogenic mechanotransduction signals, promoted the Parkin acetylation and hyperactivated mitophagy, and damaged chondrocyte health. These results may provide new insights into chondrocyte regulation by the mechanical properties of ECM, suggesting that the modification of the physical ECM properties may be a potential OA treatment strategy.
    DOI:  https://doi.org/10.1038/s41413-024-00333-9
  42. Acta Biomater. 2024 May 22. pii: S1742-7061(24)00272-1. [Epub ahead of print]
    Soft extracellular matrix drives endoplasmic reticulum stress-dependent S quiescence underlying molecular traits of pulmonary basal cells.
    Pierre-Alexandre Laval, Marie Piecyk, Paul Le Guen, Mirela-Diana Ilie, Aubepart Marion, Joelle Fauvre, Isabelle Coste, Toufic Renno, Nicolas Aznar, Celine Hadji, Camille Migdal, Cedric Duret, Philippe Bertolino, Carole Ferraro-Peyret, Alice Nicolas, Cedric Chaveroux.
      Cell culture on soft matrix, either in 2D and 3D, preserves the characteristics of progenitors. However, the mechanism by which the mechanical microenvironment determines progenitor phenotype, and its relevance to human biology, remains poorly described. Here we designed multi-well hydrogel plates with a high degree of physico-chemical uniformity to reliably address the molecular mechanism underlying cell state modification driven by physiological stiffness. Cell cycle, differentiation and metabolic activity could be studied in parallel assays, showing that the soft environment promotes an atypical S-phase quiescence and prevents cell drift, while preserving the differentiation capacities of human bronchoepithelial cells. These softness-sensitive responses are associated with calcium leakage from the endoplasmic reticulum (ER) and defects in proteostasis and enhanced basal ER stress. The analysis of available single cell data of the human lung also showed that this non-conventional state coming from the soft extracellular environment is indeed consistent with molecular feature of pulmonary basal cells. Overall, this study demonstrates that mechanical mimicry in 2D culture supports allows to maintain progenitor cells in a state of high physiological relevance for characterizing the molecular events that govern progenitor biology in human tissues. STATEMENT OF SIGNIFICANCE: This study focuses on the molecular mechanism behind the progenitor state induced by a soft environment. Using innovative hydrogel supports mimicking normal human lung stiffness, the data presented demonstrate that lung mechanics prevent drift while preserving the differentiation capabilities of lung epithelial cells. Furthermore, we show that the cells are positioned in a quiescent state in the atypical S phase. Mechanistically, we demonstrate that this quiescence: i) is driven by calcium leakage from the endoplasmic reticulum (ER) and basal activation of the PERK branch of ER stress signalling, and ii) protects cells from lethal ER stress caused by metabolic stress. Finally, we validate using human single-cell data that these molecular features identified on the soft matrix are found in basal lung cells. Our results reveal original and relevant molecular mechanisms orchestrating cell fate in a soft environment and resistance to exogenous stresses, thus providing new fundamental and clinical insights into basal cell biology.
    Keywords:  S-phase quiescence; Stiffness; cell drift and differentiation capability; physiological ER stress; resistance to metabolic stress
    DOI:  https://doi.org/10.1016/j.actbio.2024.05.033
  43. Biomacromolecules. 2024 May 22.
    Cationic Polysaccharides Bind to the Endothelial Cell Surface Extracellular Matrix Involving Heparan Sulfate.
    Lu Fu, Claire A Bridges, Ha Na Kim, Catherine Ding, Nicole Chiwei Bao Hou, Jonathan Yeow, Sandra Fok, Alexander Macmillan, James D Sterling, Shenda M Baker, Megan S Lord.
      Cationic polysaccharides have been extensively studied for drug delivery via the bloodstream, yet few have progressed to clinical use. Endothelial cells lining the blood vessel wall are coated in an anionic extracellular matrix called the glycocalyx. However, we do not fully comprehend the charged polysaccharide interactions with the glycocalyx. We reveal that the cationic polysaccharide poly(acetyl, arginyl) glucosamine (PAAG) exhibits the highest association with the endothelial glycocalyx, followed by dextran (neutral) and hyaluronan (anionic). Furthermore, we demonstrate that PAAG binds heparan sulfate (HS) within the glycocalyx, leading to intracellular accumulation. Using an in vitro glycocalyx model, we demonstrate a charge-based extent of association of polysaccharides with HS. Mechanistically, we observe that PAAG binding to HS occurs via a condensation reaction and functionally protects HS from degradation. Together, this study reveals the interplay between polysaccharide charge properties and interactions with the endothelial cell glycocalyx toward improved delivery system design and application.
    DOI:  https://doi.org/10.1021/acs.biomac.4c00477
  44. Theranostics. 2024 ;14(7): 3014-3028
    Cancer-associated fibroblast-derived periostin promotes papillary thyroid tumor growth through integrin-FAK-STAT3 signaling.
    Xiaorui Jin, Qianmei Deng, Shuting Ye, Shuting Liu, Yilong Fu, Yingfu Liu, Guoyang Wu, Gaoliang Ouyang, Tiantian Wu.
      Background: Periostin (POSTN) is a critical extracellular matrix protein in various tumor microenvironments. However, the function of POSTN in thyroid cancer progression remains largely unknown. Methods: Postn and Rag1 knock-out mice and orthotopic mouse models were used to determine the role of POSTN on papillary thyroid tumor progression. Immunofluorescence, cell co-culture, fluorescence in situ hybridization, chromatin immunoprecipitation assay, recombinant protein and inhibitor treatment were performed to explore the underlying mechanisms of POSTN-promoted papillary thyroid tumor growth. Results: POSTN is up-regulated in papillary thyroid tumors and negatively correlates with the overall survival of patients with thyroid cancer. Cancer-associated fibroblast (CAF)-derived POSTN promotes papillary thyroid tumor growth in vivo and in vitro. POSTN deficiency in CAFs significantly impairs CAF-promoted papillary thyroid tumor growth. POSTN promotes papillary thyroid tumor cell proliferation and IL-4 expression through integrin-FAK-STAT3 signaling. In turn, tumor cell-derived IL-4 induces the activation of CAFs and stimulates POSTN expression by activating STAT6. We reveal the crucial role of CAF-derived POSTN and tumor cell-derived IL-4 in driving the development of papillary thyroid tumors through the POSTN-integrin-FAK-STAT3-IL-4 pathway in tumor cells and IL-4-STAT6-POSTN signaling in CAFs. Conclusion: Our findings underscore the significance of POSTN and IL-4 as critical molecular mediators in the dynamic interplay between CAFs and tumor cells, ultimately supporting the growth of papillary thyroid tumors.
    Keywords:  IL-4; cancer-associated fibroblast; extracellular matrix; papillary thyroid tumor; periostin
    DOI:  https://doi.org/10.7150/thno.94207
  45. bioRxiv. 2024 May 13. pii: 2024.05.13.593939. [Epub ahead of print]
    Glycosaminoglycan-mediated lipoprotein uptake protects cancer cells from ferroptosis.
    Dylan Calhoon, Lingjie Sang, Divya Bezwada, Nathaniel Kim, Amrita Basu, Sheng-Chieh Hsu, Anastasia Pimentel, Bailey Brooks, Konnor La, Ana Paulina Serrano, Daniel L Cassidy, Ling Cai, Vanina Toffessi-Tcheuyap, Vitaly Margulis, Feng Cai, James Brugarolas, Ryan J Weiss, Ralph J DeBerardinis, Kıvanç Birsoy, Javier Garcia-Bermudez.
      Lipids are essential for tumours because of their structural, energetic, and signaling roles. While many cancer cells upregulate lipid synthesis, growing evidence suggests that tumours simultaneously intensify the uptake of circulating lipids carried by lipoproteins. Which mechanisms promote the uptake of extracellular lipids, and how this pool of lipids contributes to cancer progression, are poorly understood. Here, using functional genetic screens, we find that lipoprotein uptake confers resistance to lipid peroxidation and ferroptotic cell death. Lipoprotein supplementation robustly inhibits ferroptosis across numerous cancer types. Mechanistically, cancer cells take up lipoproteins through a pathway dependent on sulfated glycosaminoglycans (GAGs) linked to cell-surface proteoglycans. Tumour GAGs are a major determinant of the uptake of both low and high density lipoproteins. Impairment of glycosaminoglycan synthesis or acute degradation of surface GAGs decreases the uptake of lipoproteins, sensitizes cells to ferroptosis and reduces tumour growth in mice. We also find that human clear cell renal cell carcinomas, a distinctively lipid-rich tumour type, display elevated levels of lipoprotein-derived antioxidants and the GAG chondroitin sulfate than non-malignant human kidney. Altogether, our work identifies lipoprotein uptake as an essential anti-ferroptotic mechanism for cancer cells to overcome lipid oxidative stress in vivo, and reveals GAG biosynthesis as an unexpected mediator of this process.
    DOI:  https://doi.org/10.1101/2024.05.13.593939
  46. Biomimetics (Basel). 2024 Apr 25. pii: 262. [Epub ahead of print]9(5):
    Reducing Inert Materials for Optimal Cell-Cell and Cell-Matrix Interactions within Microphysiological Systems.
    Claudia Olaizola-Rodrigo, Héctor Castro-Abril, Ismael Perisé-Badía, Lara Pancorbo, Ignacio Ochoa, Rosa Monge, Sara Oliván.
      In the pursuit of achieving a more realistic in vitro simulation of human biological tissues, microfluidics has emerged as a promising technology. Organ-on-a-chip (OoC) devices, a product of this technology, contain miniature tissues within microfluidic chips, aiming to closely mimic the in vivo environment. However, a notable drawback is the presence of inert material between compartments, hindering complete contact between biological tissues. Current membranes, often made of PDMS or plastic materials, prevent full interaction between cell types and nutrients. Furthermore, their non-physiological mechanical properties and composition may induce unexpected cell responses. Therefore, it is essential to minimize the contact area between cells and the inert materials while simultaneously maximizing the direct contact between cells and matrices in different compartments. The main objective of this work is to minimize inert materials within the microfluidic chip while preserving proper cellular distribution. Two microfluidic devices were designed, each with a specific focus on maximizing direct cell-matrix or cell-cell interactions. The first chip, designed to increase direct cell-cell interactions, incorporates a nylon mesh with regular pores of 150 microns. The second chip minimizes interference from inert materials, thereby aiming to increase direct cell-matrix contact. It features an inert membrane with optimized macropores of 1 mm of diameter for collagen hydrogel deposition. Biological validation of both devices has been conducted through the implementation of cell migration and cell-to-cell interaction assays, as well as the development of epithelia, from isolated cells or spheroids. This endeavor contributes to the advancement of microfluidic technology, aimed at enhancing the precision and biological relevance of in vitro simulations in pursuit of more biomimetic models.
    Keywords:  inert material; macro/micropores; membranes; mesh; microfluidic devices; microphysiological systems (MPS); migration; organ-on-a-chip (OoC); spheroids
    DOI:  https://doi.org/10.3390/biomimetics9050262
  47. Front Cell Dev Biol. 2024 ;12 1378035
    Co-culture of STRO1 + human gingival mesenchymal stem cells and human umbilical vein endothelial cells in 3D spheroids: enhanced in vitro osteogenic and angiogenic capacities.
    Yushan Liu, Pei Chen, Tengfei Zhou, Jincheng Zeng, Ziyi Liu, Ruijie Wang, Yiwei Xu, Wuwei Yin, Mingdeng Rong.
      Stem cell spheroid is a promising graft substitute for bone tissue engineering. Spheroids obtained by 3D culture of STRO1+ Gingival Mesenchymal Stem Cells (sGMSCs) (sGMSC spheroids, GS) seldom express angiogenic factors, limiting their angiogenic differentiation in vivo. This study introduced a novel stem cell spheroid with osteogenic and angiogenic potential through 3D co-culture of sGMSCs and Human Umbilical Vein Endothelial Cells (HUVECs) (sGMSC/HUVEC spheroids, GHS). GHS with varying seeding ratios of sGMSCs to HUVECs (GHR) were developed. Cell fusion within the GHS system was observed via immunofluorescence. Calcein-AM/PI staining and chemiluminescence assay indicated cellular viability within the GHS. Furthermore, osteogenic and angiogenic markers, including ALP, OCN, RUNX2, CD31, and VEGFA, were quantified and compared with the control group comprising solely of sGMSCs (GS). Incorporating HUVECs into GHS extended cell viability and stability, initiated the expression of angiogenic factors CD31 and VEGFA, and upregulated the expression of osteogenic factors ALP, OCN, and RUNX2, especially when GHS with a GHR of 1:1. Taken together, GHS, derived from the 3D co-culture of sGMSCs and HUVECs, enhanced osteogenic and angiogenic capacities in vitro, extending the application of cell therapy in bone tissue engineering.
    Keywords:  Gingival mesenchymal stem cells; STRO1; angiogenic differentiation; human umbilical Vein endothelial cells; osteogenic differentiation; stem cell spheroids; three-dimensional culture
    DOI:  https://doi.org/10.3389/fcell.2024.1378035
  48. ACS Nano. 2024 May 22.
    Biomimetic Mechanically Robust Chiroptical Hydrogel Enabled by Hierarchical Bouligand Structure Engineering.
    Yulu Tang, Canhui Lu, Rui Xiong.
      Natural bouligand structures enable crustacean exoskeletons and fruits to strike a combination of exceptional mechanical robustness and brilliant chiroptical properties owing to multiscale structural hierarchy. However, integrating such a high strength-stiffness-toughness combination and photonic functionalities into synthetic hydrogels still remains a grand challenge. In this work, we report a simple yet general biomimetic strategy to construct an ultrarobust chiroptical hydrogel by closely mimicking the natural bouligand structure at multilength scale. The hierarchical structural engineering of long-range ordered cellulose nanocrystals' bouligand structure, well-defined poly(vinyl alcohol) nanocrystalline domains, and dynamic interfacial interaction synergistically contributes to the integration of high strength (23.3 MPa), superior modulus (264 MPa), and high toughness (54.7 MJ m-3), as well as extraordinary impact resistance, which far exceed their natural counterparts and synthetic photonic hydrogels. More importantly, seamless chiroptical and solvent-responsive patterns with high resolution can also be scalably integrated into the hydrogel by localized manipulation of the photonic band, while maintaining good ionic conductivity. Such exceptional mechanical-photonic combination holds tremendous potential for applications in wearable sensors, encryption, displays, and soft robotics.
    Keywords:  biomimetic hydrogel; bouligand structures; mechanical properties; photonic properties; self-assembly
    DOI:  https://doi.org/10.1021/acsnano.4c02677
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