bims-ecemfi 2024-07-07 papers

bims-ecemfi

Biomed News

on ECM and fibroblasts

Issue of 2024‒07‒07
twelve papers selected by
Badri Narayanan Narasimhan, University of California, San Diego

Proteolysis and Contractility Regulate Tissue Opening and Wound Healing by Lung Fibroblasts in 3D Microenvironments.
Tension directs cancer cell migration over fiber alignment through energy minimization.
Vimentin promotes collective cell migration through collagen networks via increased matrix remodeling and spheroid fluidity.
GelMA hydrogel dual photo-crosslinking to dynamically modulate ECM stiffness.
Substrate stress relaxation regulates neural stem cell fate commitment.
Structurally and mechanically tuned macroporous hydrogels for scalable mesenchymal stem cell-extracellular matrix spheroid production.
Matrix stiffening facilitates stemness of liver cancer stem cells by YAP activation and BMF inhibition.
A Rheological Study on the Effect of Tethering Pro- and Anti-Inflammatory Cytokines into Hydrogels on Human Mesenchymal Stem Cell Migration, Degradation, and Morphology.
Tunneling Nanotubes Mediate KRas Transport: Inducing Tumor Heterogeneity and Altering Cellular Membrane Mechanical Properties.
Discovering 3D Hidden Elasticity in Isotropic and Transversely Isotropic Materials with Physics-informed UNets.
Endothelial cell Notch signaling programs cancer-associated fibroblasts to promote tumor immune evasion.
Design of PEG-based hydrogels as soft ionic conductors.

Adv Healthc Mater. 2024 Jul 05. e2400941

Proteolysis and Contractility Regulate Tissue Opening and Wound Healing by Lung Fibroblasts in 3D Microenvironments.

Hugh Xiao, Kadidia Sylla, Xiangyu Gong, Brendan Wilkowski, Alejandro Rossello-Martinez, Seyma Nayir Jordan, Emmanuel Y Mintah, Allen Zheng, Huanxing Sun, Erica L Herzog, Michael Mak.

  Damage and repair are recurring processes in tissues, with fibroblasts playing key roles by remodeling extracellular matrices (ECM) through protein synthesis, proteolysis, and cell contractility. Dysregulation of fibroblasts can lead to fibrosis and tissue damage, as seen in idiopathic pulmonary fibrosis (IPF). In advanced IPF, tissue damage manifests as honeycombing, or voids in the lungs. This study explores how transforming growth factor-beta (TGF-β), a crucial factor in IPF, induces lung fibroblast spheroids to create voids in reconstituted collagen through proteolysis and cell contractility, a process is termed as hole formation. These voids reduce when proteases are blocked. Spheroids mimic fibroblast foci observed in IPF. Results indicate that cell contractility mediates tissue opening by stretching fractures in the collagen meshwork. Matrix metalloproteinases (MMPs), including MMP1 and MT1-MMP, are essential for hole formation, with invadopodia playing a significant role. Blocking MMPs reduces hole size and promotes wound healing. This study shows how TGF-β induces excessive tissue destruction and how blocking proteolysis can reverse damage, offering insights into IPF pathology and potential therapeutic interventions.

Keywords:  cell mechanics; cell‐matrix interactions; extracellular matrix; fibrosis; matrix metalloproteinases; mechanobiology; tissue remodeling

DOI:  https://doi.org/10.1002/adhm.202400941
Biomaterials. 2024 Jun 24. pii: S0142-9612(24)00216-3. [Epub ahead of print]311 122682

Tension directs cancer cell migration over fiber alignment through energy minimization.

Matthew R Zanotelli, Joseph P Miller, Wenjun Wang, Ismael Ortiz, Elise Tahon, Francois Bordeleau, Cynthia A Reinhart-King.

Cell migration during many fundamental biological processes including metastasis requires cells to traverse tissue with heterogeneous mechanical cues that direct migration as well as determine force and energy requirements for motility. However, the influence of discrete structural and mechanical cues on migration remains challenging to determine as they are often coupled. Here, we decouple the pro-invasive cues of collagen fiber alignment and tension to study their individual impact on migration. When presented with both cues, cells preferentially travel in the axis of tension against fiber alignment. Computational and experimental data show applying tension perpendicular to alignment increases potential energy stored within collagen fibers, lowering requirements for cell-induced matrix deformation and energy usage during migration compared to motility in the direction of fiber alignment. Energy minimization directs migration trajectory, and tension can facilitate migration against fiber alignment. These findings provide a conceptual understanding of bioenergetics during migration through a fibrous matrix.

DOI: https://doi.org/10.1016/j.biomaterials.2024.122682
bioRxiv. 2024 Jun 18. pii: 2024.06.17.599259. [Epub ahead of print]

Vimentin promotes collective cell migration through collagen networks via increased matrix remodeling and spheroid fluidity.

Minh Tri Ho Thanh, Arun Poudel, Shabeeb Ameen, Bobby Carroll, M Wu, Pranav Soman, Tao Zhang, J M Schwarz, Alison E Patteson.

The intermediate filament (IF) protein vimentin is associated with many diseases with phenotypes of enhanced cellular migration and aggressive invasion through the extracellular matrix (ECM) of tissues, but vimentin's role in in-vivo cell migration is still largely unclear. Vimentin is important for proper cellular adhesion and force generation, which are critical to cell migration; yet the vimentin cytoskeleton also hinders the ability of cells to squeeze through small pores in ECM, resisting migration. To identify the role of vimentin in collective cell migration, we generate spheroids of wide-type and vimentin-null mouse embryonic fibroblasts (mEFs) and embed them in a 3D collagen matrix. We find that loss of vimentin significantly impairs the ability of the spheroid to collectively expand through collagen networks and remodel the collagen network. Traction force analysis reveals that vimentin null spheroids exert less contractile force than their wild-type counterparts. In addition, spheroids made of mEFs with only vimentin unit length filaments (ULFs) exhibit similar behavior as vimentin-null spheroids, suggesting filamentous vimentin is required to promote 3D collective cell migration. We find the vimentin-mediated collective cell expansion is dependent on matrix metalloproteinase (MMP) degradation of the collagen matrix. Further, 3D vertex model simulation of spheroid and embedded ECM indicates that wild-type spheroids behave more fluid-like, enabling more active pulling and reconstructing the surrounding collagen network. Altogether, these results signify that VIF plays a critical role in enhancing migratory persistence in 3D matrix environments through MMP transportation and tissue fluidity.

DOI: https://doi.org/10.1101/2024.06.17.599259
Front Bioeng Biotechnol. 2024 ;12 1363525

GelMA hydrogel dual photo-crosslinking to dynamically modulate ECM stiffness.

Josephina J H M Smits, Atze van der Pol, Marie José Goumans, Carlijn V C Bouten, Ignasi Jorba.

  The dynamic nature of the extracellular matrix (ECM), particularly its stiffness, plays a pivotal role in cellular behavior, especially after myocardial infarction (MI), where cardiac fibroblasts (cFbs) are key in ECM remodeling. This study explores the effects of dynamic stiffness changes on cFb activation and ECM production, addressing a gap in understanding the dynamics of ECM stiffness and their impact on cellular behavior. Utilizing gelatin methacrylate (GelMA) hydrogels, we developed a model to dynamically alter the stiffness of cFb environment through a two-step photocrosslinking process. By inducing a quiescent state in cFbs with a TGF-β inhibitor, we ensured the direct observation of cFbs-responses to the engineered mechanical environment. Our findings demonstrate that the mechanical history of substrates significantly influences cFb activation and ECM-related gene expression. Cells that were initially cultured for 24 h on the soft substrate remained more quiescent when the hydrogel was stiffened compared to cells cultured directly to a stiff static substrate. This underscores the importance of past mechanical history in cellular behavior. The present study offers new insights into the role of ECM stiffness changes in regulating cellular behavior, with significant implications for understanding tissue remodeling processes, such as in post-MI scenarios.

Keywords:  ECM; GelMA; cardiac fibroblast (cFb); mechanical memory; photo-crosslinking; stiffness; tissue engineeering

DOI:  https://doi.org/10.3389/fbioe.2024.1363525
Proc Natl Acad Sci U S A. 2024 Jul 09. 121(28): e2317711121

Substrate stress relaxation regulates neural stem cell fate commitment.

Eric Qiao, Camille A Fulmore, David V Schaffer, Sanjay Kumar.

  Adult neural stem cells (NSCs) reside in the dentate gyrus of the hippocampus, and their capacity to generate neurons and glia plays a role in learning and memory. In addition, neurodegenerative diseases are known to be caused by a loss of neurons and glial cells, resulting in a need to better understand stem cell fate commitment processes. We previously showed that NSC fate commitment toward a neuronal or glial lineage is strongly influenced by extracellular matrix stiffness, a property of elastic materials. However, tissues in vivo are not purely elastic and have varying degrees of viscous character. Relatively little is known about how the viscoelastic properties of the substrate impact NSC fate commitment. Here, we introduce a polyacrylamide-based cell culture platform that incorporates mismatched DNA oligonucleotide-based cross-links as well as covalent cross-links. This platform allows for tunable viscous stress relaxation properties via variation in the number of mismatched base pairs. We find that NSCs exhibit increased astrocytic differentiation as the degree of stress relaxation is increased. Furthermore, culturing NSCs on increasingly stress-relaxing substrates impacts cytoskeletal dynamics by decreasing intracellular actin flow rates and stimulating cyclic activation of the mechanosensitive protein RhoA. Additionally, inhibition of motor-clutch model components such as myosin II and focal adhesion kinase partially or completely reverts cells to lineage distributions observed on elastic substrates. Collectively, our results introduce a unique system for controlling matrix stress relaxation properties and offer insight into how NSCs integrate viscoelastic cues to direct fate commitment.

Keywords:  mechanotransduction; neural stem cells; neurogenesis; stress relaxation; viscoelasticity

DOI:  https://doi.org/10.1073/pnas.2317711121
Proc Natl Acad Sci U S A. 2024 Jul 09. 121(28): e2404210121

Structurally and mechanically tuned macroporous hydrogels for scalable mesenchymal stem cell-extracellular matrix spheroid production.

Sheng Yin, Haipeng Wu, Yaying Huang, Chenjing Lu, Jian Cui, Ying Li, Bin Xue, Junhua Wu, Chunping Jiang, Xiaosong Gu, Wei Wang, Yi Cao.

  Mesenchymal stem cells (MSCs) are essential in regenerative medicine. However, conventional expansion and harvesting methods often fail to maintain the essential extracellular matrix (ECM) components, which are crucial for their functionality and efficacy in therapeutic applications. Here, we introduce a bone marrow-inspired macroporous hydrogel designed for the large-scale production of MSC-ECM spheroids. Through a soft-templating approach leveraging liquid-liquid phase separation, we engineer macroporous hydrogels with customizable features, including pore size, stiffness, bioactive ligand distribution, and enzyme-responsive degradability. These tailored environments are conducive to optimal MSC proliferation and ease of harvesting. We find that soft hydrogels enhance mechanotransduction in MSCs, establishing a standard for hydrogel-based 3D cell culture. Within these hydrogels, MSCs exist as both cohesive spheroids, preserving their innate vitality, and as migrating entities that actively secrete functional ECM proteins. Additionally, we also introduce a gentle, enzymatic harvesting method that breaks down the hydrogels, allowing MSCs and secreted ECM to naturally form MSC-ECM spheroids. These spheroids display heightened stemness and differentiation capacity, mirroring the benefits of a native ECM milieu. Our research underscores the significance of sophisticated materials design in nurturing distinct MSC subpopulations, facilitating the generation of MSC-ECM spheroids with enhanced therapeutic potential.

Keywords:  extracellular matrix; macroporous hydrogel; mechanobiology; mesenchymal stem cell; stem cell expansion

DOI:  https://doi.org/10.1073/pnas.2404210121
Biomater Adv. 2024 Jul 01. pii: S2772-9508(24)00179-1. [Epub ahead of print]163 213936

Matrix stiffening facilitates stemness of liver cancer stem cells by YAP activation and BMF inhibition.

Di Ma, Qing Luo, Guanbin Song.

  Matrix stiffening is one of the major risk factors for hepatocellular carcinoma (HCC) and drives tumor progression. The extracellular matrix (ECM) stiffness of HCC displays mechanical heterogeneity, with stiffness increasing from the core to the invasive frontier. The distribution of liver cancer stem cells (CSCs) is related to this mechanical property. However, it is not sufficiently understood how heterogeneous matrix stiffness regulates the stemness of CSCs. In this study, we developed an adjustable gelatin/alginate hydrogel to investigate the effect of various matrix stiffnesses on CSC stemness under three-dimensional culture conditions. Gelatin/alginate hydrogel with the stiffness of soft (5 kPa), medium (16 kPa), and stiff (81 kPa) were prepared by altering the concentration of calcium ions. It was found that a stiffer matrix promoted stemness-associated gene expression, reduced drug sensitivity, enhanced sphere-forming and clonogenic ability, and tumorigenic potential. Mechanistically, matrix stiffening facilitates CSC stemness by increasing Yes-associated protein (YAP) activity and inhibiting Bcl-2 modifying factor (BMF) expression. Knockdown of YAP or overexpression of BMF significantly attenuated matrix stiffening-induced stemness, suggesting the involvement of YAP and BMF in this process. Together, our results unravel the regulatory mechanism of heterogeneous matrix stiffness on CSC stemness and also provide a novel therapeutic strategy for eradicating CSCs and improving the efficiency of HCC treatment.

Keywords:  Gelatin/alginate hydrogel; Liver cancer stem cells; Matrix stiffness; Stemness; Three-dimensional culture

DOI:  https://doi.org/10.1016/j.bioadv.2024.213936
Biomacromolecules. 2024 Jul 03.

A Rheological Study on the Effect of Tethering Pro- and Anti-Inflammatory Cytokines into Hydrogels on Human Mesenchymal Stem Cell Migration, Degradation, and Morphology.

Thomas C O'Shea, Kiera J Croland, Ahmad Salem, Rylie Urbanski, Kelly M Schultz.

Polymer-peptide hydrogels are being designed as implantable materials that deliver human mesenchymal stem cells (hMSCs) to treat wounds. Most wounds can progress through the healing process without intervention. During the normal healing process, cytokines are released from the wound to create a concentration gradient, which causes directed cell migration from the native niche to the wound site. Our work takes inspiration from this process and uniformly tethers cytokines into the scaffold to measure changes in cell-mediated degradation and motility. This is the first step in designing cytokine concentration gradients into the material to direct cell migration. We measure changes in rheological properties, encapsulated cell-mediated pericellular degradation and migration in a hydrogel scaffold with covalently tethered cytokines, either tumor necrosis factor-α (TNF-α) or transforming growth factor-β (TGF-β). TNF-α is expressed in early stages of wound healing causing an inflammatory response. TGF-β is released in later stages of wound healing causing an anti-inflammatory response in the surrounding tissue. Both cytokines cause directed cell migration. We measure no statistically significant difference in modulus or the critical relaxation exponent when tethering either cytokine in the polymeric network without encapsulated hMSCs. This indicates that the scaffold structure and rheology is unchanged by the addition of tethered cytokines. Increases in hMSC motility, morphology and cell-mediated degradation are measured using a combination of multiple particle tracking microrheology (MPT) and live-cell imaging in hydrogels with tethered cytokines. We measure that tethering TNF-α into the hydrogel increases cellular remodeling on earlier days postencapsulation and tethering TGF-β into the scaffold increases cellular remodeling on later days. We measure tethering either TGF-β or TNF-α enhances cell stretching and, subsequently, migration. This work provides rheological characterization that can be used to design new materials that present chemical cues in the pericellular region to direct cell migration.

DOI: https://doi.org/10.1021/acs.biomac.4c00508
Acta Biomater. 2024 Jul 03. pii: S1742-7061(24)00360-X. [Epub ahead of print]

Tunneling Nanotubes Mediate KRas Transport: Inducing Tumor Heterogeneity and Altering Cellular Membrane Mechanical Properties.

Yawen Zheng, Jiangtao Li, Dadi Xu, Liu Liu, Yuyao Li, Jing Yi, Jiayao Dong, Daiwen Pang, Hongwu Tang.

  Mutation in oncogene KRas plays a crucial role in the occurrence and progression of numerous malignant tumors. Malignancy involves changes in cell mechanics for extensive cellular deformation during metastatic dissemination. We hypothesize that oncogene KRas mutations are intrinsic to alterations in cellular mechanics that promote malignant tumor generation and progression. Here, we demonstrate the use of optical tweezers coupled with a confocal fluorescence imaging system and gene interference technique to reveal that the mutant KRas protein can be transported between homogeneous and heterogeneous tumor cells by tunneling nanotubes (TNTs), resulting in a significant reduction of membrane tension and acceleration of membrane phospholipid flow in the recipient cells. Simultaneously, the changes in membrane mechanical properties of the tumor cells also enhance the metastatic and invasive ability of the tumors, which further contribute to the deterioration of the tumors. This finding helps to clarify the association between oncogene mutations and changes in the mechanical properties of tumor cells, which provides a theoretical basis for the development of cancer treatment strategies. STATEMENT OF SIGNIFICANCE: Here, we present a laser confocal fluorescence system integrated with optical tweezers to observe the transfer of mutant KRasG12D protein from mutant cells to wild-type cells through TNTs. Malignancy involves changes in cell mechanics for extensive cellular deformation during metastatic dissemination. Our results demonstrate a significant decrease in membrane tension and an increase in membrane phospholipid flow in recipient cells. These alterations in mechanical properties augment the migration and invasive capabilities of tumor cells, contributing to tumor malignancy. Our findings propose that cellular mechanical properties could serve as new markers for tumor development, and targeting membrane tension may hold potential as a therapeutic strategy.

Keywords:  membrane mechanical properties; oncogenic KRas; optical tweezers; tumor deterioration; tunneling nanotubes

DOI:  https://doi.org/10.1016/j.actbio.2024.06.046
Acta Biomater. 2024 Jul 01. pii: S1742-7061(24)00353-2. [Epub ahead of print]

Discovering 3D Hidden Elasticity in Isotropic and Transversely Isotropic Materials with Physics-informed UNets.

Ali Kamali, Kaveh Laksari.

  Three-dimensional variation in structural components or fiber alignments results in complex mechanical property distribution in tissues and biomaterials. In this paper, we use a physics-informed UNet-based neural network model (El-UNet) to discover the three-dimensional (3D) internal composition and space-dependent material properties of heterogeneous isotropic and transversely isotropic materials without a priori knowledge of the composition. We then show the capabilities of El-UNet by validating against data obtained from finite-element simulations of two soft tissues, namely, brain tissue and articular cartilage, under various loading conditions. We first simulated compressive loading of 3D brain tissue comprising of distinct white matter and gray matter mechanical properties undergoing small strains with isotropic linear elastic behavior, where El-UNet reached mean absolute relative errors under 1.5% for elastic modulus and Poisson's ratio estimations across the 3D volume. We showed that the 3D solution achieved by El-UNet was superior to relative stiffness mapping by inverse of axial strain and two-dimensional plane stress/plane strain approximations. Additionally, we simulated a transversely isotropic articular cartilage with known fiber orientations undergoing compressive loading, and accurately estimated the spatial distribution of all five material parameters, with mean absolute relative errors under 5%. Our work demonstrates the application of the computationally efficient physics-informed El-UNet in 3D elasticity imaging and provides methods for translation to experimental 3D characterization of soft tissues and other materials. The proposed El-UNet offers a powerful tool for both in vitro and ex vivo tissue analysis, with potential extensions to in vivo diagnostics. STATEMENT OF SIGNIFICANCE: Elasticity imaging is a technique that reconstructs mechanical properties of tissue using deformation and force measurements. Given the complexity of this reconstruction, most existing methods have mostly focused on 2D problems. Our work is the first implementation of physics-informed UNets to reconstruct three-dimensional material parameter distributions for isotropic and transversely isotropic linear elastic materials by having deformation and force measurements. We comprehensively validate our model using synthetic data generated using finite element models of biological tissues with high bio-fidelity-the brain and articular cartilage. Our method can be implemented in elasticity imaging scenarios for in vitro and ex vivo mechanical characterization of biomaterials and biological tissues, with potential extensions to in vivo diagnostics.

Keywords:  digital volume correlation; model-based elastography; physics-informed deep learning; scientific computing; tissue biomechanics

DOI:  https://doi.org/10.1016/j.actbio.2024.06.038
Res Sq. 2024 Jun 11. pii: rs.3.rs-4538031. [Epub ahead of print]

Endothelial cell Notch signaling programs cancer-associated fibroblasts to promote tumor immune evasion.

Yu Zhu, Menglan Xiang, Kevin Brulois, Nicole Lazarus, Junliang Pan, Eugene Butcher.

Stromal cells within the tumor tissue promote immune evasion as a critical strategy for cancer development and progression, but the underlying mechanisms remain poorly understood. In this study, we explore the role of endothelial cells (ECs) in the regulation of the immunosuppressive tumor microenvironment. Using mouse pancreatic ductal adenocarcinoma (PDAC) models, we found that canonical Notch signaling in endothelial cells suppresses the recruitment of antitumor T cells and promotes tumor progression by inhibiting the pro-inflammatory functions of cancer-associated fibroblasts (CAFs). Abrogation of endothelial Notch signaling modulates EC-derived angiocrine factors to enhance the pro-inflammatory activities of CAFs, which drive CXCL9/10-CXCR3-mediated T cell recruitment to inhibit tumor growth. Additionally, abrogation of endothelial Notch unleashed interferon gamma responses in the tumor microenvironment, upregulated PDL1 expression on tumor cells, and sensitized PDAC to PD1-based immunotherapy. Collectively, these data uncover a pivotal role of endothelial cells in shaping the immunosuppressive microenvironment, and suggest the potential of targeting EC-CAF interaction as a novel therapeutic modality to boost antitumor immunity.

DOI: https://doi.org/10.21203/rs.3.rs-4538031/v1
bioRxiv. 2024 Jun 21. pii: 2024.06.17.599239. [Epub ahead of print]

Design of PEG-based hydrogels as soft ionic conductors.

Gabriel J Rodriguez-Rivera, Fei Xu, Madeline Laude, Vani Shah, Abbey Nkansah, Derek Bashe, Ziyang Lan, Malgorzata Chwatko, Elizabeth Cosgriff-Hernandez.

Conductive hydrogels have gained interest in biomedical applications and soft electronics. To tackle the challenge of ionic hydrogels falling short of desired mechanical properties in previous studies, our investigation aimed to understand the pivotal structural factors that impact the conductivity and mechanical behavior of polyethylene glycol (PEG)-based hydrogels with ionic conductivity. Polyether urethane diacrylamide (PEUDAm), a functionalized long-chain macromer based on PEG, was used to synthesize hydrogels with ionic conductivity conferred by incorporating ions into the liquid phase of hydrogel. The impact of salt concentration, water content, temperature, and gel formation on both mechanical properties and conductivity was characterized to establish parameters for tuning hydrogel properties. To further expand the range of conductivity available in these ionic hydrogels, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) was incorporated as a single copolymer network or double network configuration. As expected, conductivity in these ionic gels was primarily driven by ion diffusivity and charge density, which was dependent on hydrogel network formation and swelling. Copolymer network structure had minimal effect on the conductivity which was primarily driven by counter-ion equilibrium; however, the mechanical properties and equilibrium swelling was strongly dependent on network structure. The structure-property relationships elucidated here enables the rationale design of this new double network hydrogel to achieve target properties for a broad range of applications.

DOI: https://doi.org/10.1101/2024.06.17.599239