Lygoe Kate A, Wall Ivan, Stephens Philip, Lewis Mark P
Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Grays Inn Road, London WC1X 8LD, UK.
Biol Cell. 2007 Nov;99(11):601-14. doi: 10.1042/BC20070008.
The activation of fibroblasts into myofibroblasts is a crucial event in healing that is linked to remodelling and scar formation, therefore we determined whether regulation of myofibroblast differentiation via integrins might affect wound healing responses in populations of patient-matched HOFs (human oral fibroblasts) compared with HDFs (human dermal fibroblasts).
Both the HOF and HDF cell types underwent TGF-beta1 (transforming growth factor-beta1)-induced myofibroblastic differentiation [upregulation of the expression of alpha-sma (alpha-smooth muscle actin)], although analysis of unstimulated cells indicated that HOFs contained higher basal levels of alpha-sma than HDFs (P<0.05). Functional blocking antibodies against the integrin subunits alpha 5 (fibronectin) or alpha v (vitronectin) were used to determine whether the effects of TGF-beta1 were regulated via integrin signalling pathways. alpha-sma expression in both HOFs and HDFs was down-regulated by antibodies against both alpha 5 and alpha v. Functionally, TGF-beta1 inhibited cell migration in an in vitro wound model and increased the contraction of collagen gels. Greater contraction was evident for HOFs compared with HDFs, both with and without stimulation by TGF-beta1 (P<0.05). When TGF-beta1-stimulated cells were incubated with blocking antibodies against alpha 5 and alpha v, gel contraction was decreased to that of non-stimulated cells; however, blocking alpha v or alpha 5 could not restore cellular migration in both HOFs and HDFs.
Despite intrinsic differences in their basal state, the cellular events associated with TGF-beta1-induced myofibroblastic differentiation are common to both HOFs and HDFs, and appear to require differential integrin usage; up-regulation of alpha-sma expression and increases in collagen gel contraction are vitronectin- and fibronectin-receptor-dependent processes, whereas wound re-population is not.
成纤维细胞向肌成纤维细胞的激活是愈合过程中的一个关键事件，与重塑和瘢痕形成相关，因此我们确定，与人类真皮成纤维细胞（HDFs）相比，通过整合素调节肌成纤维细胞分化是否会影响患者匹配的人类口腔成纤维细胞（HOFs）群体的伤口愈合反应。
尽管对未刺激细胞的分析表明，HOFs中α - 平滑肌肌动蛋白（α - sma）的基础水平高于HDFs（P<0.05），但HOF和HDF两种细胞类型均经历了转化生长因子 - β1（TGF - β1）诱导的肌成纤维细胞分化[α - sma表达上调]。使用针对整合素亚基α5（纤连蛋白）或αv（玻连蛋白）的功能阻断抗体来确定TGF - β1的作用是否通过整合素信号通路进行调节。针对α5和αv的抗体均下调了HOFs和HDFs中的α - sma表达。在功能上，TGF - β1在体外伤口模型中抑制细胞迁移，并增加胶原凝胶的收缩。无论有无TGF - β1刺激，HOFs的收缩均比HDFs更明显（P<0.05）。当用针对α5和αv的阻断抗体孵育TGF - β1刺激的细胞时，凝胶收缩降低至未刺激细胞的水平；然而，阻断αv或α5均不能恢复HOFs和HDFs中的细胞迁移。
尽管HOFs和HDFs在基础状态上存在内在差异，但与TGF - β1诱导的肌成纤维细胞分化相关的细胞事件在两者中是共同的，并且似乎需要不同的整合素使用方式；α - sma表达上调和胶原凝胶收缩增加是依赖玻连蛋白和纤连蛋白受体的过程，而伤口再填充则不是。
