Type III and V collagens modulate the expression and assembly of EDA+ fibronectin in the extracellular matrix of defective Ehlers–Danlos syndrome fibroblasts

• Published in: Biochimica et biophysica acta Vol. 1820; no. 10; pp. 1576 - 1587
• Main Authors: Zoppi, Nicoletta, Ritelli, Marco, Colombi, Marina
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2012
• Subjects: Alternative splicing; Case-Control Studies; Cells, Cultured; Collagen; Collagen Type III - pharmacology; Collagen Type V - pharmacology; EDA region; Ehlers-Danlos Syndrome - metabolism; Ehlers-Danlos Syndrome - pathology; Ehlers–Danlos syndrome; energy-dispersive X-ray analysis; extracellular matrix; Extracellular Matrix - drug effects; Extracellular Matrix - metabolism; Female; fibroblasts; Fibroblasts - drug effects; Fibroblasts - metabolism; Fibroblasts - pathology; Fibronectin; fibronectins; Fibronectins - genetics; Fibronectins - metabolism; fluorescence microscopy; Focal Adhesion Kinase 1 - metabolism; Focal Adhesion Kinase 1 - physiology; gene expression; Gene Expression Regulation - drug effects; genes; growth factors; Humans; Integrin alpha5beta1 - metabolism; Integrins; Integrins - metabolism; Male; messenger RNA; mutation; phosphorylation; Protein Isoforms - genetics; Protein Isoforms - metabolism; Protein Multimerization - drug effects; quantitative polymerase chain reaction; receptors; signal transduction; transcription (genetics); Western blotting; Alternative splicing; CE; EDA region; FN; FN1; CM; ECM; Fibronectin; FAK; Ehlers–Danlos syndrome; COLLs; Collagen; DOC-IS; COLLIII; COLLV; Integrins
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2012.06.004

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. Real-time PCR, immunofluorescence microscopy, and Western 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. COLLV-treated cEDS and COLLIII-treated vEDS fibroblasts up-regulate the FN1 gene expression, modulate 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. 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. 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. ► Ehlers–Danlos syndrome cells lack collagens and fibronectin extracellular matrix. ► Collagens III and V restore the matrix containing the EDA+ fibronectin isotype. ► Collagens III and V induce fibronectin gene expression and maturation of EDA+ mRNA. ► Collagens induce recruitment of α5β1 and α9β1 integrin and FAK-mediated signal transduction.