bims-ecemfi 2024-06-23 papers

bims-ecemfi

Biomed News

on ECM and fibroblasts

Issue of 2024‒06‒23
twenty-two papers selected by
Badri Narayanan Narasimhan, University of California, San Diego

Intracellular pH dynamics respond to microenvironment stiffening and mediate vasculogenic mimicry through β-catenin.
Patient-specific colorectal-cancer-associated fibroblasts modulate tumor microenvironment mechanics.
Development of an Optical System for Strain Drop Measurement of Osteosarcoma Cells on Substrates with Different Stiffness.
T cells use focal adhesions to pull themselves through confined environments.
Phenotypic switching mechanisms determine the structure of cell migration into extracellular matrix under the 'go-or-grow' hypothesis.
Nanofiber-microwell cell culture system for spatially patterned differentiation of pluripotent stem cells in 3D.
Engineering Tumor Stroma Morphogenesis Using Dynamic Cell-Matrix Spheroid Assembly.
Disodium Cromoglycate Templates Anisotropic Short-Chain PEG Hydrogels.
Human-derived Tumor-On-Chip model to study the heterogeneity of breast cancer tissue.
Effect of particle stiffness and surface properties on the non-linear viscoelasticity of dense microgel suspensions.
Dissecting TGF-β-induced glioblastoma invasion with engineered hyaluronic acid hydrogels.
The importance of 3D fibre architecture in cancer and implications for biomaterial model design.
Thickness-Resolved Electrochemiluminescence Microscopy of Extracellular Matrix at Tumor Tissues for Rapid Cancer Diagnosis.
Dynamics of multicellular swirling on micropatterned substrates.
Mechanical characterization of soft biomaterials: which time and spatial scale to choose?
c-Src induced vascular malformations require localised matrix degradation at focal adhesions.
Nanotube topography rejuvenates the senescence of mesenchymal stem cells by activating YAP signalling.
Measuring the Shape, Stiffness, and Interface Tension of Droplets with the Scanning Ion Conductance Microscope.
YAP dysregulation triggers hypertrophy by CCN2 secretion and TGFβ uptake in human pluripotent stem cell-derived cardiomyocytes.
Dynamic Regulation of Cell Mechanotransduction through Sequentially Controlled Mobile Surfaces.
Lactate supports cell-autonomous ECM production to sustain metastatic behavior in prostate cancer.
Low densities of immune cells indicate unfavourable overall survival in patients suffering from squamous cell carcinoma of the lung.

bioRxiv. 2024 Jun 04. pii: 2024.06.04.597454. [Epub ahead of print]

Intracellular pH dynamics respond to microenvironment stiffening and mediate vasculogenic mimicry through β-catenin.

Leah M Lund, Angelina N Marchi, Laura Alderfer, Eva Hall, Jacob Hammer, Keelan J Trull, Donny Hanjaya-Putra, Katharine A White.

Dysregulated intracellular pH (pHi) dynamics and an altered tumor microenvironment have emerged as drivers of cancer cell phenotypes. However, the molecular integration between the physical properties of the microenvironment and dynamic intracellular signaling responses remains unclear. Here, we use two metastatic cell models, one breast and one lung, to assess pHi response to varying extracellular matrix (ECM) stiffness. To experimentally model ECM stiffening, we use two tunable-stiffness hydrogel systems: Matrigel and hyaluronic acid (HA) gels, which mimic the increased protein secretion and crosslinking associated with ECM stiffening. We find that single-cell pHi decreases with increased ECM stiffness in both hydrogel systems and both metastatic cell types. We also observed that stiff ECM promotes vasculogenic mimicry (VM), a phenotype associated with metastasis and resistance. Importantly, we show that decreased pHi is both a necessary and sufficient mediator of VM, as raising pHi on stiff ECM reduces VM phenotypes and lowering pHi on soft ECM drives VM. We characterize β-catenin as a pH-dependent molecular mediator of pH-dependent VM, where stiffness-driven changes in β-catenin abundance can be overridden by increased pHi. We uncover a dynamic relationship between matrix stiffness and pHi, thus suggesting pHi dynamics can override mechanosensitive cell responses to the extracellular microenvironment.

DOI: https://doi.org/10.1101/2024.06.04.597454
iScience. 2024 Jun 21. 27(6): 110060

Patient-specific colorectal-cancer-associated fibroblasts modulate tumor microenvironment mechanics.

Auxtine Micalet, Anuja Upadhyay, Yousef Javanmardi, Camila Gabriela de Brito, Emad Moeendarbary, Umber Cheema.

  Cancer-associated fibroblasts (CAFs) play a major role in reorganizing the physical tumor micro-environment and changing tissue stiffness. Herein, using an engineered three-dimensional (3D) model that mimics the tumor's native biomechanical environment, we characterized the changes in matrix stiffness caused by six patient-specific colorectal CAF populations. After 21 days of culture, atomic force microscopy (AFM) was performed to precisely measure the local changes in tissue stiffness. Each CAF population exhibited heterogeneity in remodeling capabilities, with some patient-derived cells stiffening the matrix and others softening it. Tissue stiffening was mainly attributed to active contraction of the matrix by the cells, whereas the softening was due to enzymatic activity of matrix-cleaving proteins. This measured heterogeneity was lost when the CAFs were cocultured with colorectal cancer cells, as all samples significantly soften the tissue. The interplay between cancer cells and CAFs was critical as it altered any heterogeneity exhibited by CAFs alone.

Keywords:  biomechanics; cancer; cell biology; stem cells research

DOI:  https://doi.org/10.1016/j.isci.2024.110060
Sensors (Basel). 2024 May 24. pii: 3383. [Epub ahead of print]24(11):

Development of an Optical System for Strain Drop Measurement of Osteosarcoma Cells on Substrates with Different Stiffness.

Ludovica Apa, Maria Vittoria Martire, Serena Carraro, Marianna Cosentino, Zaccaria Del Prete, Barbara Peruzzi, Emanuele Rizzuto.

  Adherent cells perceive mechanical feedback from the underlying matrix and convert it into biochemical signals through a process known as mechanotransduction. The response to changes in the microenvironment relies on the cell's mechanical properties, including elasticity, which was recently identified as a biomarker for various diseases. Here, we propose the design, development, and characterization of a new system for the measurement of adherent cells' strain drop, a parameter correlated with cells' elasticity. To consider the interplay between adherent cells and the host extracellular matrix, cell stretching was combined with adhesion on substrates with different stiffnesses. The technique is based on the linear stretching of silicone chambers, high-speed image acquisition, and feedback for image centering. The system was characterized in terms of the strain homogeneity, impact of collagen coating, centering capability, and sensitivity. Subsequently, it was employed to measure the strain drop of two osteosarcoma cell lines, low-aggressive osteoblast-like SaOS-2 and high-aggressive 143B, cultured on two different substrates to recall the stiffness of the bone and lung extracellular matrices. Results demonstrated good substrate homogeneity, a negligible effect of the collagen coating, and an accurate image centering. Finally, the experimental results showed an average strain drop that was lower in the 143B cells in comparison with the SaOS-2 cells in all the tested conditions.

Keywords:  biomechanics; cell elasticity; novel measurement system; osteosarcoma; silicone stretchable chambers; stiffness; strain drop; strain measurements

DOI:  https://doi.org/10.3390/s24113383
J Cell Biol. 2024 Oct 07. pii: e202310067. [Epub ahead of print]223(10):

T cells use focal adhesions to pull themselves through confined environments.

Alexia Caillier, David Oleksyn, Deborah J Fowell, Jim Miller, Patrick W Oakes.

Immune cells are highly dynamic and able to migrate through environments with diverse biochemical and mechanical compositions. Their migration has classically been defined as amoeboid under the assumption that it is integrin independent. Here, we show that activated primary Th1 T cells require both confinement and extracellular matrix proteins to migrate efficiently. This migration is mediated through small and dynamic focal adhesions that are composed of the same proteins associated with canonical mesenchymal cell focal adhesions, such as integrins, talin, and vinculin. These focal adhesions, furthermore, localize to sites of contractile traction stresses, enabling T cells to pull themselves through confined spaces. Finally, we show that Th1 T cells preferentially follow tracks of other T cells, suggesting that these adhesions modify the extracellular matrix to provide additional environmental guidance cues. These results demonstrate not only that the boundaries between amoeboid and mesenchymal migration modes are ambiguous, but that integrin-mediated focal adhesions play a key role in T cell motility.

DOI: https://doi.org/10.1083/jcb.202310067
Math Biosci. 2024 Jun 19. pii: S0025-5564(24)00100-7. [Epub ahead of print] 109240

Phenotypic switching mechanisms determine the structure of cell migration into extracellular matrix under the 'go-or-grow' hypothesis.

Rebecca M Crossley, Kevin J Painter, Tommaso Lorenzi, Philip K Maini, Ruth E Baker.

  A fundamental feature of collective cell migration is phenotypic heterogeneity which, for example influences tumour progression and relapse. While current mathematical models often consider discrete phenotypic structuring of the cell population, in-line with the 'go-or-grow' hypothesis (Hatzikirou et al., 2012; Stepien et al., 2018), they regularly overlook the role that the environment may play in determining the cells' phenotype during migration. Comparing a previously studied volume-filling model for a homogeneous population of generalist cells that can proliferate, move and degrade extracellular matrix (ECM) (Crossley et al., 2023) to a novel model for a heterogeneous population comprising two distinct sub-populations of specialist cells that can either move and degrade ECM or proliferate, this study explores how different hypothetical phenotypic switching mechanisms affect the speed and structure of the invading cell populations. Through a continuum model derived from its individual-based counterpart, insights into the influence of the ECM and the impact of phenotypic switching on migrating cell populations emerge. Notably, specialist cell populations that cannot switch phenotype show reduced invasiveness compared to generalist cell populations, while implementing different forms of switching significantly alters the structure of migrating cell fronts. This key result suggests that the structure of an invading cell population could be used to infer the underlying mechanisms governing phenotypic switching.

Keywords:  Collective cell migration; Extracellular matrix; Go-or-grow; Mathematical modelling; Phenotypic switching; Travelling wave

DOI:  https://doi.org/10.1016/j.mbs.2024.109240
Mater Today Bio. 2024 Jun;26 101109

Nanofiber-microwell cell culture system for spatially patterned differentiation of pluripotent stem cells in 3D.

Youyi Tai, Robyn Goodrich, Maricela Maldonado, Jessica Ortiz, Jeniree Martinez, Gerardo Ico, Angel Ko, Hung Ping Shih, Jin Nam.

  The intricate interplay between biochemical and physical cues dictates pluripotent stem cell (PSC) differentiation to form various tissues. While biochemical modulation has been extensively studied, the role of biophysical microenvironments in early lineage commitment remains elusive. Here, we introduce a novel 3D cell culture system combining electrospun nanofibers with microfabricated polydimethylsiloxane (PDMS) patterns. This system enables the controlled formation of semispherical human induced pluripotent stem cell (hiPSC) colonies, facilitating the investigation of local mechanical stem cell niches on mechano-responsive signaling and lineage specification. Our system unveiled spatially organized RhoA activity coupled with actin-myosin cable formation, suggesting mechano-dependent hiPSC behaviors. Nodal network analysis of RNA-seq data revealed RhoA downstream regulation of YAP signaling, DNA histone modifications, and patterned germ layer specification. Notably, altering colony morphology through controlled PDMS microwell shaping effectively modulated the spatial distribution of mechano-sensitive mediators and subsequent differentiation. This study provides a cell culture platform to decipher the role of biophysical cues in early embryogenesis, offering valuable insights for material design in tissue engineering and regenerative medicine applications.

Keywords:  Electrospun nanofibers; Mechanobiology; Microfabrication; Pluripotent stem cell differentiation

DOI:  https://doi.org/10.1016/j.mtbio.2024.101109
bioRxiv. 2024 Mar 22. pii: 2024.03.19.585805. [Epub ahead of print]

Engineering Tumor Stroma Morphogenesis Using Dynamic Cell-Matrix Spheroid Assembly.

Michael J Buckenmeyer, Elizabeth A Brooks, Madison S Taylor, Liping Yang, Ronald J Holewinski, Thomas J Meyer, Mélissa Galloux, Marcial Garmendia-Cedillos, Thomas J Pohida, Thorkell Andresson, Brad St Croix, Matthew T Wolf.

The tumor microenvironment consists of resident tumor cells organized within a compositionally diverse, three-dimensional (3D) extracellular matrix (ECM) network that cannot be replicated in vitro using bottom-up synthesis. We report a new self-assembly system to engineer ECM-rich 3D MatriSpheres wherein tumor cells actively organize and concentrate microgram quantities of decellularized ECM dispersions which modulate cell phenotype. 3D colorectal cancer (CRC) MatriSpheres were created using decellularized small intestine submucosa (SIS) as an orthotopic ECM source that had greater proteomic homology to CRC tumor ECM than traditional ECM formulations such as Matrigel. SIS ECM was rapidly concentrated from its environment and assembled into ECM-rich 3D stroma-like regions by mouse and human CRC cell lines within 4-5 days via a mechanism that was rheologically distinct from bulk hydrogel formation. Both ECM organization and transcriptional regulation by 3D ECM cues affected programs of malignancy, lipid metabolism, and immunoregulation that corresponded with an in vivo MC38 tumor cell subpopulation identified via single cell RNA sequencing. This 3D modeling approach stimulates tumor specific tissue morphogenesis that incorporates the complexities of both cancer cell and ECM compartments in a scalable, spontaneous assembly process that may further facilitate precision medicine.

DOI: https://doi.org/10.1101/2024.03.19.585805
ACS Appl Mater Interfaces. 2024 Jun 17.

Disodium Cromoglycate Templates Anisotropic Short-Chain PEG Hydrogels.

Juan Chen, Yimin Luo.

  Anisotropic hydrogels have found widespread applications in biomedical engineering, particularly as scaffolds for tissue engineering. However, it remains a challenge to produce them using conventional fabrication methods, without specialized synthesis or equipment, such as 3D printing and unidirectional stretching. In this study, we explore the self-assembly behaviors of polyethylene glycol diacrylate (PEGDA), using disodium cromoglycate (DSCG), a lyotropic chromonic liquid crystal, as a removable template. The affinity between short-chain PEGDA (Mn = 250) and DSCG allows polymerization to take place at the DSCG surface, thereby forming anisotropic hydrogel networks with fibrin-like morphologies. This process requires considerable finesse as the phase behaviors of DSCG depend on a multitude of factors, including the weight percentage of PEGDA and DSCG, the chain length of PEGDA, and the concentration of ionic species. The key to modulating the microstructures of the all-PEG hydrogel networks is through precise control of the DSCG concentration, resulting in anisotropic mechanical properties. Using these anisotropic hydrogel networks, we demonstrate that human dermal fibroblasts are particularly sensitive to the alignment order. We find that cells exhibit a density-dependent activation pattern of a Yes-associated protein, a mechanotransducer, corroborating its role in enabling cells to translate external mechanical and morphological patterns to specific behaviors. The flexibility of modulating microstructure, along with PEG hydrogels' biocompatibility and biodegradability, underscores their potential use for tissue engineering to create functional structures with physiological morphologies.

Keywords:  PEG hydrogels; anisotropic hydrogels; cell alignment; lyotropic chromonic liquid crystal; phase diagram

DOI:  https://doi.org/10.1021/acsami.4c07181
Biomater Adv. 2024 Jun 06. pii: S2772-9508(24)00158-4. [Epub ahead of print]162 213915

Human-derived Tumor-On-Chip model to study the heterogeneity of breast cancer tissue.

Shabnam Jeibouei, Arefeh Khazraie Monfared, Ali Hojat, Amir Reza Aref, Forough Shams, Mandana Dolati, Afshin Moradi, Masoumeh Hosseini, Seyed Mohammadreza Javadi, Mohammad Ajoudanian, Zahra Molavi, Maryam Moghaddam, Farzaneh Mohammadi, Ghader Nuoroozi, Sahar Khakpour Naeimi, Minoo Shahani, Hakimeh Zali, Mohammad Esmaeil Akbari, Ebrahim Mostafavi.

  One of the leading causes that complicate the treatment of some malignancies, including breast cancer, is tumor heterogeneity. In addition to inter-heterogeneity and intra-heterogeneity of tumors that reflect the differences between cancer cell characteristics, heterogeneity in the tumor microenvironment plays a critical role in tumor progression and could be considered an overlooked and a proper target for the effective selection of therapeutic approaches. Due to the difficulty of completely capturing tumor heterogeneity in conventional detection methods, Tumor-on-Chip (TOC) devices with culturing patient-derived spheroids could be an appropriate alternative. In this research, human-derived spheroids from breast cancer individuals were cultured for 6 days in microfluidic devices. To compare TOC data with conventional detection methods, immunohistochemistry (IHC) and ITRAQ data were employed, and various protein expressions were validated using the transcriptomic databases. The behavior of the spheroids in the collagen matrix and the cell viability were monitored over 6 days of culture. IHC and immunocytochemistry (ICC) results revealed that inter and intra-heterogeneity of tumor spheroids are associated with HER2/ER expression. HER2 expression levels revealed a more important biomarker associated with invasion in the 3D culturing of spheroids. The expression levels of CD163 (as a marker for Ma2 macrophages) and CD44 (a marker for cancer stem cells (CSCs)) were also evaluated. Interestingly, the levels of M2a macrophages and CSCs were higher in triple-negative specimens and samples that showed higher migration and invasion. Cell density and extracellular matrix (ECM) stiffness were also important factors affecting the migration and invasion of the spheroids through the matrix. Among these, rigid ECM revealed a more crucial role than cell density. To sum up, these research findings demonstrated that human-derived spheroids from breast cancer specimens in microfluidic devices provide a dynamic condition for predicting tumor heterogeneity in patients, which can help move the field forward for better and more accurate therapeutic strategies.

Keywords:  Breast cancer; Human-derived tumor spheroid; Microfluidics; Tumor heterogeneity; Tumor-On-Chip; Tumor-associated macrophage; cancer stem cell

DOI:  https://doi.org/10.1016/j.bioadv.2024.213915
J Colloid Interface Sci. 2024 Jun 03. pii: S0021-9797(24)01208-6. [Epub ahead of print]672 814-823

Effect of particle stiffness and surface properties on the non-linear viscoelasticity of dense microgel suspensions.

Jacopo Vialetto, Shivaprakash N Ramakrishna, Lucio Isa, Marco Laurati.

  HYPOTHESIS: Particle surface chemistry and internal softness are two fundamental parameters in governing the mechanical properties of dense colloidal suspensions, dictating structure and flow, therefore of interest from materials fabrication to processing.EXPERIMENTS: Here, we modulate softness by tuning the crosslinker content of poly(N-isopropylacrylamide) microgels, and we adjust their surface properties by co-polymerization with polyethylene glycol chains, controlling adhesion, friction and fuzziness. We investigate the distinct effects of these parameters on the entire mechanical response from restructuring to complete fluidization of jammed samples at varying packing fractions under large-amplitude oscillatory shear experiments, and we complement rheological data with colloidal-probe atomic force microscopy to unravel variations in the particles' surface properties.
FINDINGS: Our results indicate that surface properties play a fundamental role at smaller packings; decreasing adhesion and friction at contact causes the samples to yield and fluidify in a lower deformation range. Instead, increasing softness or fuzziness has a similar effect at ultra-high densities, making suspensions able to better adapt to the applied shear and reach complete fluidization over a larger deformation range. These findings shed new light on the single-particle parameters governing the mechanical response of dense suspensions subjected to deformation, offering synthetic approaches to design materials with tailored mechanical properties.

Keywords:  Atomic force microscopy; Colloidal particles; Large-amplitude oscillatory shear (LAOS); Microgels; Rheology; Yielding

DOI:  https://doi.org/10.1016/j.jcis.2024.05.214
APL Bioeng. 2024 Jun;8(2): 026125

Dissecting TGF-β-induced glioblastoma invasion with engineered hyaluronic acid hydrogels.

Kwasi Yeboa Amofa, Katherine Michelle Patterson, Jessica Ortiz, Sanjay Kumar.

Glioma stem cells (GSCs) contribute to rapid cellular invasion in glioblastoma (GBM). Transforming growth factor-β (TGF-β) has been strongly implicated in supporting key GSC functions, including stemness, immunosuppression, and resistance. Although TGF-β is well-known as a driver of cancer invasion, how TGF-β supports the invasion of GSCs is not well understood. Progress in understanding mechanisms of TGF-β-driven invasion in GSC-derived tumors has been limited by an absence of three-dimensional (3D) culture systems that support TGF-β-stimulated invasion. Here, we show that 3D hyaluronic acid (HA) matrices can address this need. We perform bioinformatic analysis of human glioma datasets, which reveals progressive enrichment of TGF-β-related gene expression with increasingly aggressive glioma grade and GBM subtype. We then experimentally screen the invasion of a panel of human GSC spheroids through a set of 3D matrix systems, including collagen I, Matrigel, and HA, and find that only HA recapitulates TGF-β-induced invasion. We then show that GSCs differ in their ability to invade HA in a way that can be predicted from TGF-β receptor 2 expression and SMAD2 phosphorylation. GSC spheroid invasion depends strongly on the presence of RGD peptides on the HA backbone but is surprisingly independent of matrix metalloprotease degradability. Finally, we demonstrate that TGF-β stimulates invasion through SMAD-dependent signaling, consistent with recent observations that TGF-β/SMAD signals drive tumor microtube formation and invasion. Our work supports further development of HA as a matrix platform for dissecting contributions of TGF-β and other cytokines to GBM invasion and screening of cytokine-dependent invasion in human tumors.

DOI: https://doi.org/10.1063/5.0203213
Nat Rev Cancer. 2024 Jun 17.

The importance of 3D fibre architecture in cancer and implications for biomaterial model design.

J C Ashworth, T R Cox.

The need for improved prediction of clinical response is driving the development of cancer models with enhanced physiological relevance. A new concept of 'precision biomaterials' is emerging, encompassing patient-mimetic biomaterial models that seek to accurately detect, treat and model cancer by faithfully recapitulating key microenvironmental characteristics. Despite recent advances allowing tissue-mimetic stiffness and molecular composition to be replicated in vitro, approaches for reproducing the 3D fibre architectures found in tumour extracellular matrix (ECM) remain relatively unexplored. Although the precise influences of patient-specific fibre architecture are unclear, we summarize the known roles of tumour fibre architecture, underlining their implications in cell-matrix interactions and ultimately clinical outcome. We then explore the challenges in reproducing tissue-specific 3D fibre architecture(s) in vitro, highlighting relevant biomaterial fabrication techniques and their benefits and limitations. Finally, we discuss imaging and image analysis techniques (focussing on collagen I-optimized approaches) that could hold the key to mapping tumour-specific ECM into high-fidelity biomaterial models. We anticipate that an interdisciplinary approach, combining materials science, cancer research and image analysis, will elucidate the role of 3D fibre architecture in tumour development, leading to the next generation of patient-mimetic models for mechanistic studies and drug discovery.

DOI: https://doi.org/10.1038/s41568-024-00704-8
ACS Appl Mater Interfaces. 2024 Jun 12.

Thickness-Resolved Electrochemiluminescence Microscopy of Extracellular Matrix at Tumor Tissues for Rapid Cancer Diagnosis.

Dongni Han, Mi Yang, Zengyu Feng, Yulian Wu, Neso Sojic, Dechen Jiang.

  The traditional recognition of extracellular matrix (ECM) at tissue sections relies on the time-consuming immunofluorescence that could not meet the demand of rapid diagnosis. Herein, we introduce a thickness-resolved electrochemiluminescence (ECL) microscopy to image thin-layer ECM at tissue sections for fast histopathological analysis. The unique surface-confined ECL mechanism enables to unveil the diversity and complexity of multiple tissue structures with varying thicknesses. Notably, the short lifetimes and the limited diffusion of electrogenerated coreactant radicals combined with their chemical reactivity result in a 2-fold increase in ECL intensity on ECM structures compared to the remaining tissue, enabling ECM visualization without specific labeling. The further quantitation of the ECM localization within tissue sections furnishes crucial insights into tumor progression and, more importantly, differentiates carcinoma and paracancerous tissues from patients in less than 30 min. Moreover, the reported electrochemistry-based microscopy is a dynamic approach allowing to investigate the transport, tortuosity, and trafficking properties through the tissues. This thickness-resolved recognition strategy not only opens new avenues for imaging complex samples but also holds promise for expediting tissue pathologic diagnosis, offering a more automated protocol with enhanced quantitative data compared to current intraoperative pathology methods.

Keywords:  electrochemiluminescence microscopy; extracellular matrix; histopathological analysis; thickness resolved; tissue section

DOI:  https://doi.org/10.1021/acsami.4c05735
Proc Natl Acad Sci U S A. 2024 Jun 25. 121(26): e2400804121

Dynamics of multicellular swirling on micropatterned substrates.

Xi Li, Bin Chen.

  Chirality plays a crucial role in biology, as it is highly conserved and fundamentally important in the developmental process. To better understand the relationship between the chirality of individual cells and that of tissues and organisms, we develop a generalized mechanics model of chiral polarized particles to investigate the swirling dynamics of cell populations on substrates. Our analysis reveals that cells with the same chirality can form distinct chiral patterns on ring-shaped or rectangular substrates. Interestingly, our studies indicate that an excessively strong or weak individual cellular chirality hinders the formation of such chiral patterns. Our studies also indicate that there exists the influence distance of substrate boundaries in chiral patterns. Smaller influence distances are observed when cell-cell interactions are weaker. Conversely, when cell-cell interactions are too strong, multiple cells tend to be stacked together, preventing the formation of chiral patterns on substrates in our analysis. Additionally, we demonstrate that the interaction between cells and substrate boundaries effectively controls the chiral distribution of cellular orientations on ring-shaped substrates. This research highlights the significance of coordinating boundary features, individual cellular chirality, and cell-cell interactions in governing the chiral movement of cell populations and provides valuable mechanics insights into comprehending the intricate connection between the chirality of single cells and that of tissues and organisms.

Keywords:  cell populations; chirality; mechanics model; micropatterned substrate

DOI:  https://doi.org/10.1073/pnas.2400804121
Soft Matter. 2024 Jun 18.

Mechanical characterization of soft biomaterials: which time and spatial scale to choose?

Ekaterina S Krivega, Svetlana L Kotova, Peter S Timashev, Yuri M Efremov.

The mechanical properties of soft gels hold significant relevance in biomedicine and biomaterial design, including the development of tissue engineering constructs and bioequivalents. It is important to adequately characterize the gel's mechanical properties since they play a role both in the overall structural properties of the construct and the physiological responses of cells. The question remains which approach for the mechanical characterization is most suitable for specific biomaterials. Our investigation is centered on the comparison of three types of gels and four distinct mechanical testing techniques: shear rheology, compression, microindentation, and nanoindentation by atomic force microscopy. While analyzing an elastic homogeneous synthetic hydrogel (a polyacrylamide gel), we observed close mechanical results across the different testing techniques. However, our findings revealed more distinct outcomes when assessing a highly viscoelastic gel (Ecoflex) and a heterogeneous biopolymer hydrogel (enzymatically crosslinked gelatin). To ensure precise data interpretation, we introduced correction factors to account for the boundary conditions inherent in many of the testing methods. The results of this study underscore the critical significance of considering both the temporal and spatial scales in mechanical measurements of biomaterials. Furthermore, they encourage the employment of a combination of diverse testing techniques, particularly in the characterization of heterogeneous viscoelastic materials such as biological samples. The obtained results will contribute to the refinement of mechanical testing protocols and advance the development of soft gels for tissue engineering.

DOI: https://doi.org/10.1039/d4sm00530a
J Cell Sci. 2024 Jun 17. pii: jcs.262101. [Epub ahead of print]

c-Src induced vascular malformations require localised matrix degradation at focal adhesions.

Patricia Essebier, Mikaela Keyser, Teodor Yordanov, Brittany Hill, Alexander Yu, Ivar Noordstra, Alpha S Yap, Samantha J Stehbens, Anne K Lagendijk, Lilian Schimmel, Emma J Gordon.

  Endothelial cells lining the blood vessel wall communicate intricately with the surrounding extracellular matrix, translating mechanical cues into biochemical signals. Moreover, vessels require the capability to enzymatically degrade the matrix surrounding them, to facilitate vascular expansion. c-Src plays a key role in blood vessel growth, with its loss in the endothelium reducing vessel sprouting and focal adhesion signalling. Here, we show that constitutive activation of c-Src in endothelial cells results in rapid vascular expansion, operating independently of growth factor stimulation or fluid shear stress forces. This is driven by an increase in focal adhesion signalling and size, with enhancement of localised secretion of matrix metalloproteinases responsible for extracellular matrix remodelling. Inhibition of matrix metalloproteinase activity results in a robust rescue of the vascular expansion elicited by heightened c-Src activity. This supports the premise that moderating focal adhesion-related events and matrix degradation can counteract abnormal vascular expansion, with implications for pathologies driven by unusual vascular morphologies.

Keywords:  Angiogenesis; Extracellular matrix; Focal adhesions; c-Src

DOI:  https://doi.org/10.1242/jcs.262101
J Mater Chem B. 2024 Jun 21.

Nanotube topography rejuvenates the senescence of mesenchymal stem cells by activating YAP signalling.

Yanping Sun, Yejia Yu, Shixing Ma, Chengcheng Liao, Jian Yang, Yun Lyu, Xuanhao Zhang, Jingyi Zhang, Weidong Tian, Li Liao.

Improving the regenerative ability of senescent stem cells is a critical issue in combating aging. The destiny and function of senescent stem cells are controlled by the niche, including the physical architecture of the surface of the extracellular matrix (ECM). In this study, we explored the functions of TiO2 nanotube topography on mesenchymal stem cells (MSCs) under senescence, as well as its mechanical effects on senescence. First, we created different nanotube topographies on the titanium samples. Next, we cultured senescent mesenchymal stem cells (S-MSCs) on samples with various nanotube topographies to determine suitable parameters. We found nanotube with a diameter of 10 nm significantly alleviated the cellular senescence of S-MSCs and improved the osteogenic differentiation of S-MSCs in vitro. Using an ectopic periodontium regeneration model, we confirmed that specific nanotube topography could promote tissue regeneration of S-MSCs in vivo. Moreover, we demonstrated that nanotube topography activated YAP in S-MSCs and reformed nuclear-cytoskeletal morphology to inhibit senescence. Taken together, our study establishes a bridge linking between nano-topography, mechanics, and senescence, suggesting a potential strategy to improve tissue regeneration in aged individuals by providing optimized surface topography on biomaterials.

DOI: https://doi.org/10.1039/d3tb02828c
ACS Nano. 2024 Jun 13.

Measuring the Shape, Stiffness, and Interface Tension of Droplets with the Scanning Ion Conductance Microscope.

Johannes Rheinlaender, Tilman E Schäffer.

  Imaging and probing liquid-liquid interfaces at the micro- and nanoscale are of high relevance, for example, in materials science, surface chemistry, and microfluidics. However, existing imaging techniques are limited in resolution, average over large sample areas, or interact with the sample. Here, we present a method to quantify the shape, stiffness, and interface tension of liquid droplets with the scanning ion conductance microscope (SICM), providing submicrometer resolution and the ability to perform noncontact mechanical measurements. We show that we can accurately image the three-dimensional shape of micrometer-sized liquid droplets made of, for example, decane, hexane, or different oils. We then introduce numerical models to quantitatively obtain their stiffness and interface tension from SICM data. We verified our method by measuring the interface tension of decane droplets changing under the influence of surfactants at different concentrations. Finally, we use SICM to resolve the dissolution dynamics of decane droplets, showing that droplet shape exhibits different dissolution modes and stiffness continuously increases while the interface tension remains constant. We thereby demonstrate that SICM is a useful method to investigate liquid-liquid interfaces on the microscale with applications in materials or life sciences.

Keywords:  finite element modeling; liquid–liquid interfaces; scanning ion conductance microscopy; scanning probe microscopy; surface tension

DOI:  https://doi.org/10.1021/acsnano.4c02743
bioRxiv. 2024 Jun 05. pii: 2024.06.03.597045. [Epub ahead of print]

YAP dysregulation triggers hypertrophy by CCN2 secretion and TGFβ uptake in human pluripotent stem cell-derived cardiomyocytes.

Orlando Chirikian, Mohamed A Faynus, Markus Merk, Zachary Singh, Christopher Muray, Jeffrey Pham, Alex Chialastri, Alison Vander Roest, Alex Goldstein, Trevor Pyle, Kerry V Lane, Brock Roberts, Jacqueline E Smith, Ruwanthi N Gunawardane, Nathan J Sniadecki, David L Mack, Jennifer Davis, Daniel Bernstein, Sebastian J Streichan, Dennis O Clegg, Siddharth S Dey, Maxwell Z Wilson, Beth L Pruitt.

Hypertrophy Cardiomyopathy (HCM) is the most prevalent hereditary cardiovascular disease - affecting >1:500 individuals. Advanced forms of HCM clinically present with hypercontractility, hypertrophy and fibrosis. Several single-point mutations in b-myosin heavy chain (MYH7) have been associated with HCM and increased contractility at the organ level. Different MYH7 mutations have resulted in increased, decreased, or unchanged force production at the molecular level. Yet, how these molecular kinetics link to cell and tissue pathogenesis remains unclear. The Hippo Pathway, specifically its effector molecule YAP, has been demonstrated to be reactivated in pathological hypertrophic growth. We hypothesized that changes in force production (intrinsically or extrinsically) directly alter the homeostatic mechano-signaling of the Hippo pathway through changes in stresses on the nucleus. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), we asked whether homeostatic mechanical signaling through the canonical growth regulator, YAP, is altered 1) by changes in the biomechanics of HCM mutant cardiomyocytes and 2) by alterations in the mechanical environment. We use genetically edited hiPSC-CM with point mutations in MYH7 associated with HCM, and their matched controls, combined with micropatterned traction force microscopy substrates to confirm the hypercontractile phenotype in MYH7 mutants. We next modulate contractility in healthy and disease hiPSC-CMs by treatment with positive and negative inotropic drugs and demonstrate a correlative relationship between contractility and YAP activity. We further demonstrate the activation of YAP in both HCM mutants and healthy hiPSC-CMs treated with contractility modulators is through enhanced nuclear deformation. We conclude that the overactivation of YAP, possibly initiated and driven by hypercontractility, correlates with excessive CCN2 secretion (connective tissue growth factor), enhancing cardiac fibroblast/myofibroblast transition and production of known hypertrophic signaling molecule TGFβ. Our study suggests YAP being an indirect player in the initiation of hypertrophic growth and fibrosis in HCM. Our results provide new insights into HCM progression and bring forth a testbed for therapeutic options in treating HCM.

DOI: https://doi.org/10.1101/2024.06.03.597045
Nano Lett. 2024 Jun 18.

Dynamic Regulation of Cell Mechanotransduction through Sequentially Controlled Mobile Surfaces.

Wenyan Xie, Linjie Ma, Peng Wang, Xiaojing Liu, Di Wu, Yuan Lin, Zhiqin Chu, Yong Hou, Qiang Wei.

  The physical properties of nanoscale cell-extracellular matrix (ECM) ligands profoundly impact biological processes, such as adhesion, motility, and differentiation. While the mechanoresponse of cells to static ligands is well-studied, the effect of dynamic ligand presentation with "adaptive" properties on cell mechanotransduction remains less understood. Utilizing a controllable diffusible ligand interface, we demonstrated that cells on surfaces with rapid ligand mobility could recruit ligands through activating integrin α5β1, leading to faster focal adhesion growth and spreading at the early adhesion stage. By leveraging UV-light-sensitive anchor molecules to trigger a "dynamic to static" transformation of ligands, we sequentially activated α5β1 and αvβ3 integrins, significantly promoting osteogenic differentiation of mesenchymal stem cells. This study illustrates how manipulating molecular dynamics can directly influence stem cell fate, suggesting the potential of "sequentially" controlled mobile surfaces as adaptable platforms for engineering smart biomaterial coatings.

Keywords:  biointerfaces; cell adhesion; diffusible ligands; ligand recruitment; mechanotransduction

DOI:  https://doi.org/10.1021/acs.nanolett.4c01371
EMBO Rep. 2024 Jun 21.

Lactate supports cell-autonomous ECM production to sustain metastatic behavior in prostate cancer.

Luigi Ippolito, Assia Duatti, Marta Iozzo, Giuseppina Comito, Elisa Pardella, Nicla Lorito, Marina Bacci, Erica Pranzini, Alice Santi, Giada Sandrini, Carlo V Catapano, Sergio Serni, Pietro Spatafora, Andrea Morandi, Elisa Giannoni, Paola Chiarugi.

  Extracellular matrix (ECM) is a major component of the tumor environment, promoting the establishment of a pro-invasive behavior. Such environment is supported by both tumor- and stromal-derived metabolites, particularly lactate. In prostate cancer (PCa), cancer-associated fibroblasts (CAFs) are major contributors of secreted lactate, able to impact on metabolic and transcriptional regulation in cancer cells. Here, we describe a mechanism by which CAF-secreted lactate promotes in PCa cells the expression of genes coding for the collagen family. Lactate-exploiting PCa cells rely on increased α-ketoglutarate (α-KG) which activates the α-KG-dependent collagen prolyl-4-hydroxylase (P4HA1) to support collagen hydroxylation. De novo synthetized collagen plays a signaling role by activating discoidin domain receptor 1 (DDR1), supporting stem-like and invasive features of PCa cells. Inhibition of lactate-induced collagen hydroxylation and DDR1 activation reduces the metastatic colonization of PCa cells. Overall, these results provide a new understanding of the link between collagen remodeling/signaling and the nutrient environment exploited by PCa.

Keywords:  CAFs; Collagen Hydroxylation; Collagen Signaling; Lactate Metabolism

DOI:  https://doi.org/10.1038/s44319-024-00180-z
Sci Rep. 2024 06 20. 14(1): 14250

Low densities of immune cells indicate unfavourable overall survival in patients suffering from squamous cell carcinoma of the lung.

Simone Steffens, Claudia Kayser, Anuschka Roesner, Justyna Rawluk, Severin Schmid, Eleni Gkika, Gian Kayser.

Carcinogenesis and tumor proliferation are characterized by a complex interaction of cancer cells with the tumor microenvironment. In particular, a tumor-promoting effect can be assumed for the stroma and its fibroblasts. An influence of the immune system on non small cell lung cancer (NSCLC) is now also suspected. In our study, we examined 309 sections of squamous cell carcinoma (SCC), a subtype of NSCLC. We determined the cell densities and areas of the different tissues in SCC using the software QuPath. Spearman rank correlation showed a significant positive correlation between the different tumor cell densities and stromal cell densities, and between tumor cell densities and immune cell densities. Overall survival curves by the Kaplan-Meier method revealed a prominent negative curve in cases of low immune cell density. Based on our results, we can assume a positive influence of the tumor microenvironment, especially the stromal cells, on tumor proliferation in SCC. We have also revealed that low density of immune cells is prognostically unfavorable.

DOI: https://doi.org/10.1038/s41598-024-64956-y