Project description:Hypertrophic scar (HTS) formation is characterized by exuberant fibroproliferation for reasons that remain poorly understood1. One important but often overlooked component of wound repair is mechanical force, which regulates reciprocal cell-matrix interactions through focal adhesion components including focal adhesion kinase (FAK)1,2. Here we report that FAK is activated following cutaneous injury and that this activation is potentiated by mechanical loading. Transgenic mice lacking fibroblast-specific FAK exhibit significantly less fibrosis in a preclinical model of HTS formation. Inflammatory pathways involving monocyte chemoattractant protein-1 (MCP-1), a chemokine highly implicated in human skin fibrosis3, are triggered following FAK activation, mechanistically linking physical force to fibrosis. Further, small molecule inhibition of FAK effectively abrogates fibroproliferative mechanisms in human cells and significantly reduces scar formation in vivo. Collectively, these findings establish a molecular basis for HTS formation based on the mechanical activation of fibroblast-specific FAK and demonstrate the therapeutic potential of targeted mechanomodulatory strategies.
Project description:Hypertrophic scar (HTS) formation is characterized by exuberant fibroproliferation for reasons that remain poorly understood1. One important but often overlooked component of wound repair is mechanical force, which regulates reciprocal cell-matrix interactions through focal adhesion components including focal adhesion kinase (FAK)1,2. Here we report that FAK is activated following cutaneous injury and that this activation is potentiated by mechanical loading. Transgenic mice lacking fibroblast-specific FAK exhibit significantly less fibrosis in a preclinical model of HTS formation. Inflammatory pathways involving monocyte chemoattractant protein-1 (MCP-1), a chemokine highly implicated in human skin fibrosis3, are triggered following FAK activation, mechanistically linking physical force to fibrosis. Further, small molecule inhibition of FAK effectively abrogates fibroproliferative mechanisms in human cells and significantly reduces scar formation in vivo. Collectively, these findings establish a molecular basis for HTS formation based on the mechanical activation of fibroblast-specific FAK and demonstrate the therapeutic potential of targeted mechanomodulatory strategies. Wildtype murine tissue was harvested at either day 6 or 14 post-injury following 48 hours or 10 days of mechanical loading, respectively (n=4 mice per group per time point). Murine RNA was isolated, labeled, and hybridized to the GeneChip microarray according to the manufacturer’s protocols (Affymetrix, Santa Clara, CA, USA). Each gene in the microarray was represented by 20 oligonucleotide pairs, with each pair consisting of an oligonucleotide perfectly matched to the cDNA sequence, and a second oligonucleotide containing a single base mismatch. Raw microarray data (sample intensity files) were processed using GeneSpring GX 11.0 (Agilent Technologies Inc., Santa Clara, CA, USA).
Project description:The allostatic adaption VSMCs to a mechanical perturbation relies on the interaction of the CSK contractile components to generate cellular force, as well as the engagement of the mechanosensitive signaling elements, i.e. the interplay among mechanosensitive ion channels, integrin-focal adhesion-actin axis, and calcium signal that convert the mechanical input into cellular contractile response We used miroarray to analyze the biophysical mechanisms underlying aging-associated decline in mechanosensation and VSMC functions
Project description:Mechanical force has been shown to regulate periodontal ligament cells (PDLs) behaviors. However, different force types lead to distinct PDLs’ responses. Here, the differential gene expression profiling of PDLs subjected to static and intermittent compressive forces was examined using RNA sequencing technique. Results demonstrated that the static and intermittent compressive force treated PDLs exhibited the differential regulation genes. KEGG pathway enrichment analysis revealed that focal adhesion and transforming growth factor beta signaling pathway were commonly upregulated while calcium signaling pathway was downregulated in both static and intermittent compressive force-treated PDLs. Interestingly, Wnt signaling pathway was upregulated only in the PDLs that subjected to the intermittent compressive force.
Project description:Purpose: mechanical homeostasis is a crucial process for Humen dermal fibroblast cell (HDFs) survival and functionality. Cell can sense environmental change and modify the expression of extracellular matrix, focal adhesion and cytoskeleton protein to maintain the correct mechanical homeostasis. In this study we observed change in microRNA levels linked with mechanical response. HDFs were seeded for 48 our on PDMS 3 kPa and 30 kPa substrate coating with fibronectin to simulate "soft" and "stiff" substrate, then sRNA-seq was performed.
Project description:Metabolic Dysfunction Associated Steatohepatitis (MASH) is characterized by excess circulating toxic lipids, hepatic steatosis, and liver inflammation. Monocyte adhesion to the liver sinusoidal endothelial cells (LSEC) and transendothelial migration (TEM) are crucial in the inflammatory process. LSEC under lipotoxic stress develops a pro-inflammatory phenotype known as endotheliopathy. However, the mediators of endotheliopathy remain obscure. Primary mouse LSEC isolated from C57BL/6J mice on chow or MASH-inducing diets rich in fat, fructose, and cholesterol (FFC) were subjected to multi-omics profiling. Mice with established MASH, due to a choline-deficient high-fat diet (CDHFD) or FFC diet, were treated with two structurally distinct GSK3 inhibitors [LY2090314, elraglusib (9-ING-41)]. Integrated pathway analysis of mouse LSEC proteome and transcriptome indicates that leukocyte TEM and focal adhesion are major pathways altered in MASH. Kinome profiling of the LSEC phospho-proteome identified GSK3β as the major kinase hub in MASH. GSK3β activating phosphorylation was increased in primary human LSEC treated with the toxic lipid palmitate and in human MASH. Palmitate upregulated the expression of C-X-C motif chemokine ligand 2, intracellular adhesion molecule 1, and phosphorylated focal adhesion kinase, via a GSK3-dependant mechanism. Congruently, the adhesive and transendothelial migratory capacities of primary human neutrophils and THP-1 monocytes through LSEC monolayer under lipotoxic stress were reduced by GSK3 inhibition. Treatment with the GSK3 inhibitors LY2090314 and elraglusib ameliorated liver inflammation, injury, and fibrosis in FFC and CDHFD-fed mice, respectively. Immunophenotyping of intrahepatic leukocytes from CDHFD-fed mice treated with elraglusib using cytometry by the time of flight showed reduced proinflammatory monocyte-derived macrophages and monocyte-derived dendritic cells infiltration.GSK3 inhibition attenuates lipotoxicity-induced LSEC endotheliopathy and may serve as a potential therapeutic strategy in human MASH.
Project description:Cell adhesion to the extracellular matrix occurs through integrin-mediated focal adhesions, which sense the mechanical properties of the substrate and impact cellular functions such as cell migration. Mechanotransduction at focal adhesions affects the actomyosin network and contributes to cell migration. Despite being key players in cell adhesion and migration, the role of microtubules in mechanotransduction has been overlooked. Here, we show that substrate rigidity increases microtubule acetylation through β1 integrin signalling in primary rat astrocytes. Moreover, αTAT1, the enzyme responsible for microtubule acetylation, interacts with a major mechanosensing focal adhesion protein, Talin, and is able to tune the distribution of focal adhesions depending on the matrix rigidity. αTAT1 also reorganises the actomyosin network, increases traction force generation and cell migration speed on stiff substrates. Mechanistically, acetylation of microtubules promotes the release of microtubule-associated RhoGEF, GEF-H1 into the cytoplasm, which then leads to RhoA activation and high actomyosin contractility. Thus, we propose a novel feedback loop involving a crosstalk between microtubules and actin in mechanotransduction at focal adhesions whereby, cells sense the rigidity of the substrate through integrin-mediated adhesions, modulate their levels of microtubule acetylation, which then controls the actomyosin cytoskeleton and force transmission on the substrate to promote mechanosensitive cell migration.
Project description:Aim of this work is to verify if pericytes (Pc) residing in ischemic failing human hearts display altered mechano-transduction properties and to assess which alterations of the mechano-sensing machinery are associated with the observed impaired response to mechanical cues. Results: microvascular rarefaction and defects of YAP/TAZ activation characterize failing human hearts. Although both donor (D-) and explanted (E-) heart derived cardiac pericytes (CPc) support angiogenesis, D-CPc exert this effect significantly better than E-CPc. The latter are characterized by reduced focal adhesion density, decreased activation of the focal adhesion kinase (FAK)/ Crk-associated substrate(CAS) pathway, low expression of caveolin-1, and defective transduction of extracellular stiffness into cytoskeletal stiffening, together with an impaired response to both fibronectin and lysophosphatidic acid. Importantly, Mitogen-activated protein kinase kinase inhibition restores YAP/TAZ nuclear translocation.
Project description:The goal of this study was to identify transcripts, which are differentially regulatulated in the presence and absence of Focal Adhesion Kinase. As Focal Adhesion Kinase activity can depend upon cell density (Snijder et al. Nature 2009), biological replicates where cells, were seeded very sparsely or confluently, were used. Focal Adhesion Kinase Knockout (ATCC CRL-2644) and Rescue Cells (Sieg et al. 1998, clone DA2) were seeded at two different concentrations. Replicas refer to biological replicates, performed on different days. Only one single technical replicate has been done per biological replicate.