Grella Alexandra, Kole Denis, Holmes William, Dominko Tanja
Department of Biology and Biotechnology, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts, 01609.
Center for Biomedical Sciences and Engineering, University of Nova Gorica, Nova Gorica 5000, Slovenia.
J Cell Biochem. 2016 Apr;117(4):1000-8. doi: 10.1002/jcb.25386. Epub 2015 Oct 6.
Deposition of collagen-based extracellular matrix by fibroblasts during wound healing leads to scar formation--a typical outcome of the healing process in soft tissue wounds. The process can, however, be skewed in favor of tissue regeneration by manipulation of wound environment. Low oxygen conditions and supplementation with FGF2 provide extracellular cues that drive wound fibroblasts towards a pro-regenerative phenotype. Under these conditions, fibroblasts dramatically alter expression of many genes among which the most significantly deregulated are extracellular matrix and adhesion molecules. Here we investigate the mechanism of a collagen I binding integrin α11 (ITGA11) deregulation in response to low oxygen-mediated FGF2 effects in dermal fibroblasts. Using RT-PCR, qRT-PCR, Western blotting, and immunocytochemistry, we describe significant down-regulation of ITGA11. Decrease in ITGA11 is associated with its loss from focal adhesions. We show that loss of ITGA11 requires FGF2 induced ERK1/2 activity and in the presence of FGF2, ITGA11 expression cannot be rescued by TGFβ1, a potent activator of ITGA11. Our results indicate that FGF2 may be redirecting fibroblasts towards an anti-fibrotic phenotype by overriding TGFβ1 mediated ITGA11 expression.
在伤口愈合过程中，成纤维细胞沉积基于胶原蛋白的细胞外基质会导致瘢痕形成，这是软组织伤口愈合过程的典型结果。然而，通过对伤口环境的操控，这一过程可能会偏向于组织再生。低氧条件和补充FGF2提供了细胞外信号，促使伤口成纤维细胞向促再生表型转变。在这些条件下，成纤维细胞显著改变许多基因的表达，其中失调最明显的是细胞外基质和黏附分子。在这里，我们研究了真皮成纤维细胞中，I型胶原蛋白结合整合素α11（ITGA11）响应低氧介导的FGF2效应而失调的机制。通过逆转录聚合酶链反应（RT-PCR）、定量逆转录聚合酶链反应（qRT-PCR）、蛋白质免疫印迹法和免疫细胞化学，我们描述了ITGA11的显著下调。ITGA11的减少与其从粘着斑的丢失有关。我们表明，ITGA11的丢失需要FGF2诱导的细胞外信号调节激酶1/2（ERK1/2）活性，并且在FGF2存在的情况下，ITGA11的表达不能被TGFβ1（一种ITGA11的有效激活剂）挽救。我们的结果表明，FGF2可能通过超越TGFβ1介导的ITGA11表达，将成纤维细胞重定向为抗纤维化表型。
