TRIDIMENSIONAL RECONSTRUCTION, BIOCHEMICAL AND MOLECULAR PROFILE OF COLLAGEN V IN SKIN AND LUNG FIBROBLASTS CULTURE FROM SSc INDICATE A FAILING IN FIBRILOGENESIS

Abstract

Background. The type V collagen (COL V) mutations are involved in collagen vascular diseases, such as SSc, in which an unusual accumulation of this collagen was demonstrated (Pathol Res Pract 2004; 200:681). In this context, our purpose was to analyse the 3D reconstruction, biochemical and molecular profile of COL Vα1 and α2 chains in skin and lung fibroblasts culture from patients with SSc. Methods. Lung biopsies of seven patients, skin of six patients and respective matched controls were obtained from SSc according ACR. For fibroblast culture skin and lung evaluations were used the following score: intense expression (1–4), fibroblast number/field (1, 2) and collagen fibres architecture (1–3). The total evaluations were: mild (3–5), moderate (6, 7) and severe (8, 9). COLV 3D reconstruction was performed by confocal microscopy, COL Vα1 and Vα2 gene expression in fibroblasts of skin and lung was performed in PCR–RT and COLV protein expression by immunoblotting. Results. The structure of COL V fibre in 3D reconstruction showed distorted and strongly thickened fibres in skin and lung fibroblasts with irregular bundles of COL V distributed in parallel and perpendicular arrangements resulting in a dense network in SSc patients compared with thin fibres pattern from the healthy controls. Collagen quantification showed increase of COL V fibres expression in SSc cutaneous fibroblast [82.5 (9.5)% vs 47.5 (9.5)%, P = 0.002] and lung fibroblast 38.87 (2.99)% vs 20.33 (7.50)%, P = 0,002) compared with respective controls. The molecular evaluation demonstrated an increased of COL Vα1 and α2 mRNA expression in SSc fibroblast skin when compared with control [1.375 (0.373) au vs 0.0047 (0.0013) au, P = 0.05). Similar results were observed in lung [1.61 (0.654) vs 0.99 (0.51) au; P = 0.05).The proportion COL Vα1/COL Vα2 mRNA in fibroblast lung and skin was higher in SSc than in controls being the chains ratio 1 : 2. COL V chains from skin and lung fibroblasts presented alteration of molecular weight of the quoted chain. Conclusion. The overexpression and the unusual organization of COLV fibres, besides the biochemical changes, suggest an interference with the fibrillogenesis process in skin and pulmonary fibrosis from SSc patients, reinforcing the participation of this collagen in pathogenesis of SSc and open new therapeutic perspectives for these patients.