Dally Jordanna, Khan Jabur S, Voisey Alex, Charalambous Chrisandrea, John Hannah L, Woods Emma L, Steadman Robert, Moseley Ryan, Midgley Adam C
Stem Cells, Wound Repair & Regeneration, Oral & Biomedical Sciences, School of Dentistry, Cardiff University, Cardiff CF14 4XY, UK.
Cardiff Institute of Tissue Engineering & Repair (CITER), Cardiff University, Cardiff CF10 3AX, UK.
Int J Mol Sci. 2017 Aug 24;18(9):1843. doi: 10.3390/ijms18091843.
Oral mucosal wounds are characterized by rapid healing with minimal scarring, partly attributable to the "enhanced" wound healing properties of oral mucosal fibroblasts (OMFs). Hepatocyte growth factor (HGF) is a pleiotropic growth factor, with potential key roles in accelerating healing and preventing fibrosis. HGF can exist as full-length or truncated (HGF-NK), NK1 and NK2 isoforms. As OMFs display elevated HGF expression compared to dermal fibroblasts (DFs), this study investigated the extent to which HGF mediates the preferential cellular functions of OMFs, and the influence of pro-fibrotic, transforming growth factor-β₁ (TGF-β₁) on these responses. Knockdown of HGF expression in OMFs by short-interfering RNA (siHGF) significantly inhibited OMF proliferative and migratory responses. Supplementation with exogenous TGF-β₁ also significantly inhibited proliferation and migration, concomitant with significantly down-regulated HGF expression. In addition, knockdown abrogated OMF resistance to TGF-β₁-driven myofibroblast differentiation, as evidenced by increased α-smooth muscle actin (α-SMA) expression, F-actin reorganisation, and stress fibre formation. Responses were unaffected in siHGF-transfected DFs. OMFs expressed significantly higher full-length HGF and NK1 levels compared to patient-matched DFs, whilst NK2 expression was similar in both OMFs and DFs. Furthermore, NK2 was preferentially expressed over NK1 in DFs. TGF-β₁ supplementation significantly down-regulated full-length HGF and NK1 expression by OMFs, while NK2 was less affected. This study demonstrates the importance of HGF in mediating "enhanced" OMF cellular function. We also propose that full-length HGF and HGF-NK1 convey desirable wound healing properties, whilst fibroblasts preferentially expressing more HGF-NK2 readily undergo TGF-β₁-driven differentiation into myofibroblasts.
口腔黏膜伤口的特点是愈合迅速且瘢痕形成极少，部分原因是口腔黏膜成纤维细胞（OMF）具有“增强的”伤口愈合特性。肝细胞生长因子（HGF）是一种多效性生长因子，在加速愈合和预防纤维化方面可能发挥关键作用。HGF可以以全长或截短形式（HGF-NK）、NK1和NK2亚型存在。由于与皮肤成纤维细胞（DF）相比，OMF显示出更高的HGF表达，本研究调查了HGF介导OMF优先细胞功能的程度，以及促纤维化的转化生长因子-β₁（TGF-β₁）对这些反应的影响。通过短干扰RNA（siHGF）敲低OMF中的HGF表达可显著抑制OMF的增殖和迁移反应。补充外源性TGF-β₁也显著抑制增殖和迁移，同时HGF表达显著下调。此外，敲低消除了OMF对TGF-β₁驱动的肌成纤维细胞分化的抗性，α-平滑肌肌动蛋白（α-SMA）表达增加、F-肌动蛋白重组和应力纤维形成证明了这一点。在转染siHGF的DF中，反应未受影响。与患者匹配的DF相比，OMF表达的全长HGF和NK1水平显著更高，而NK2在OMF和DF中的表达相似。此外，在DF中，NK2的表达优先于NK1。补充TGF-β₁显著下调OMF的全长HGF和NK1表达，而NK2受影响较小。本研究证明了HGF在介导“增强的”OMF细胞功能中的重要性。我们还提出，全长HGF和HGF-NK1具有理想的伤口愈合特性，而优先表达更多HGF-NK2的成纤维细胞容易经历TGF-β₁驱动的向肌成纤维细胞的分化。
