1,721,166 research outputs found
Type V and type III collagen modulate the expression and assembly of fibronectin extracellar matrix in classic and vascular Ehlers-Danlos syndrome fibroblasts, affecting cell survival and migration
No full textExtracellular matrix (ECM) regulates cell proliferation, migration, survival and gene expression, via signal transduction pathways differentially activated by ECM ligands interacting with specific integrins. In vitro cultured skin fibroblasts derived from classic and vascular Ehlers-Danlos syndrome (cEDS, vEDS) patients show a fibronectin (FN)-ECM disarray, consequent to the altered type V and III collagen (COLLV, COLLIII) expression and deposition. The COLL-FN-ECM disassembly is associated to the reduction of the COLLs a2b1 integrin receptor, the FN a5b1 integrin receptor substitution with avb3, rescuing from anoikis through a FAK-independent and epidermal growth factor-mediated signalling, and to the impairment of in vitro migration. The role in the ECM-mediated survival and migration of COLLV and COLLIII, respectively mutated in cEDS and vEDS, was investigated in cultured skin fibroblasts by indirect immunofluorescence, Western blotting, Q-PCR and in vitro wounding assay. Purified COLLV and COLLIII restore in cEDS and vEDS cells respectively, the COLL-ECM and the a2b1 integrin. This receptor transduces for the FN gene expression and splicing modulation, EDA+-FN isoform synthesis and organisation, a5b1-phosphorylated FAK colocalisation and EDA+-FN specific a9b1 integrin up-regulation. The induced COLL-FN-ECM, binding to a2b1-a5b1-a9b1 integrin complex, restores the FAK-mediated survival and the cell migration. These findings show the role of COLLV- and COLLIII-ECM-mediated transduction signalling in in vitro cEDS and vEDS fibroblasts’ survival and migration and give insights in the comprehension of the molecular mechanisms regulating these processes in vivo
Type III and V collagens modulate the expression and assembly of EDA+ fibronectin in the extracellular matrix of defective Ehlers-Danlos syndrome fibroblasts
No full textBackground: Alternative splicing of EDA fibronectin (FN) region is a cell type- and development-regulated
mechanism controlled by pathological processes, growth factors and extracellular matrix (ECM). Classic
and vascular Ehlers–Danlos syndrome (cEDS and vEDS) are connective tissue disorders caused by COL5A1/
COL5A2 and COL3A1 gene mutations, leading to an in vivo abnormal collagen fibrillogenesis and to an in
vitro defective organisation in the ECM of type V (COLLV) and type III collagen (COLLIII). These defects induce
the FN-ECM disarray and the decrease of COLLs and FN receptors, the α2β1 and α5β1 integrins. Purified
COLLV and COLLIII restore the COLL-FN-ECMs in both EDS cell strains.
Methods: Real-time PCR, immunofluorescence microscopy, andWestern blotting were used to investigate the
effects of COLLs on FN1 gene expression, EDA region alternative splicing, EDA+-FN-ECM assembly, α5β1
integrin and EDA+-FN-specific α9 integrin subunit organisation, α5β1 integrin and FAK co-regulation in
EDS fibroblasts.
Results: COLLV-treated cEDS and COLLIII-treated vEDS fibroblasts up-regulate the FN1 gene expression, mod-
ulate the EDA+ mRNA maturation and increase the EDA+-FN levels, thus restoring a control-like FN-ECM,
which elicits the EDA+-FN-specific α9β1 integrin organisation, recruits the α5β1 integrin and switches on
the FAK binding and phosphorylation.
Conclusion: COLLs regulate the EDA+-FN-ECM organisation at transcriptional and post-transcriptional level
and activate the α5β1–FAK complexes. COLLs also recruit the α9β1 integrin involved in the assembly of
the EDA+-FN-ECM in EDS cells.
General significance: The knowledge of the COLLs-ECM role in FN isotype expression and in EDA+-FN-ECM-
mediated signal transduction adds insights in the ECM remodelling mechanisms in EDS cells.
© 2012 Published by Elsevier B.V. 42
43
FAK-independent alphavbeta3 integrin-EGFR complexes rescue from anoikis matrix-defective fibroblasts
No full textExtracellular matrix (ECM) binding to integrin receptors regulates cell cycle progression and survival. In adherent cells, ECM disassembly induces anoikis, the apoptotic pathway switched on by loss of adhesion. ECM-deficient Ehlers-Danlos syndrome (EDS) fibroblasts, to adhere to rare fibronectin (FN) fibrils, and to proliferate, only organize, as FN receptor, the alphavbeta3 integrin. We report that in EDS cells the alphavbeta3 integrin is bound to talin and vinculin, but not to tensin, and that actin cytoskeleton is disorganized. Furthermore, in EDS cells Bcl-2 is down-regulated and caspases are active. We provide evidence that the antibody-mediated alphavbeta3 integrin or the FN inhibition induces anoikis in EDS cells. The alphavbeta3 integrin transduces survival signals to pp60src-mediated tyrosine phosphorylated paxillin, instead than to FAK, and interacts with EGF receptor (EGFR). This complex, when activated by EGF and FN, signals for the rescue of EDS cells from anoikis. Therefore, EDS cells, through the alphavbeta3 integrin-EGFR complexes, engage a paxillin- but not FAK-mediated pathway of cell survival
- …
