Obesity-Dependent Changes in Interstitial ECM Mechanics Promote Breast Tumorigenesis Scientists examined the cellular, structural, and molecular changes that happen in breast tissue in obese animals and people. They found that obesity induces fibrotic remodeling of the mammary fat pad, leading to changes in extracellular matrix (ECM) mechanical properties, via myofibroblasts and adipose stem cells, regardless of ovary function. [Sci Transl Med] Abstract | Press Release Mechanical Forces Regulate the Interactions of Fibronectin and Collagen I in Extracellular Matrix Investigators exploited fibronectin (Fn)-FRET probes as mechanical strain sensors and demonstrated that collagen I fibers preferentially co-localize with more-relaxed Fn fibrils in the extracellular matrix of fibroblasts in cell culture. Fiber stretch-assay studies reveal that collagen I’s Fn-binding domain is responsible for the mechano-regulated interaction. [Nat Commun] Full Article Reduced Matrix Rigidity Promotes Neonatal Cardiomyocyte Dedifferentiation, Proliferation and Clonal Expansion Scientists explored the role of the mechanical properties of the underlying matrix in the regulation of cardiomyocyte (CM) maturation. They showed that rat and mouse neonatal CMs cultured on rigid surfaces exhibited increased myofibrillar organization, spread morphology, and reduced cell cycle activity. [eLife] Abstract | Full Article Keratinocyte Microvesicles Regulate the Expression of Multiple Genes in Dermal Fibroblasts Researchers investigated whether microvesicle-like structures are present in human wounds and whether they affect wound healing-associated gene expression in dermal fibroblasts. [J Invest Dermatol] Abstract GnRH-(1-5) Activates Matrix Metallopeptidase-9 to Release Epidermal Growth Factor and Promote Cellular Invasion Researchers demonstrated that these gonadotropin-releasing hormone (GnRH)-(1–5) effects are dependent on increased matrix metallopeptidase (MMP)-9 enzymatic activity in the Ishikawa and ECC-1 cell lines. Furthermore, the effects of GnRH-(1–5) mediated by GPR101 and the subsequent increase in MMP-9 enzymatic activity lead to an increase in cellular invasion. [Mol Cell Endocrinol] Abstract Soluble Extracellular Matrix Metalloproteinase Inducer (EMMPRIN, EMN) Regulates Cancer-Related Cellular Functions by Homotypic Interactions with Surface CD147 Scientists employed a recombinant soluble, fully glycosylated EMMPRIN domain as a tool to characterize the structural basis of EMMPRIN-EMMPRIN receptor-contacts and their functional effects on MCF-7 breast carcinoma cells. [FEBS J] Abstract Dexamethasone-Mediated Activation of Fibronectin Matrix Assembly Reduces Dispersal of Primary Human Glioblastoma Cells Researchers utilized a broad range of qualitative and quantitative assays and the use of a human glioblastoma multiforme (GBM) tissue microarray and freshly-isolated primary human GBM cells grown both as conventional 2D cultures and as 3D spheroids to explore the role of dexamethasone and fibronectin matrix assembly in modulating various parameters that can significantly influence tumor cell dispersal. [PLoS One] Full Article Extracellular Matrix Stiffness Regulates Osteogenic Differentiation through MAPK Activation Investigators showed that extracellular matrix stiffness regulates mesenchymal stem cell fate through ERK or JNK activation. Specifically, a stiff hydrogel matrix stimulates osteogenic differentiation concomitant with increased nuclear localization of transcriptional coactivator with PDZ-binding motif, but inhibits adipogenic differentiation. [PLoS One] Full Article Lower Crosslinking Density Enhances Functional Nucleus Pulposus-Like Matrix Elaboration by Human Mesenchymal Stem Cells in Carboxymethylcellulose Hydrogels The authors investigated the influence of carboxymethylcellulose crosslinking density, by varying macromer concentration and modification percentage, on nucleus pulposus-like differentiation of encapsulated human mesenchymal stem cells. Constructs of lower macromer concentration exhibited significantly greater collagen II accumulation, more homogeneous distribution of extracellular matrix macromolecules, and a temporal increase in mechanical properties compared to hydrogels of higher macromer concentration. [J Biomed Res] Abstract |