Department of Dermatology, Ehime University Graduate School of Medicine, Shitsukawa, Toon City, Ehime 791-0295, Japan.
J Dermatol Sci. 2012 Jan;65(1):50-7. doi: 10.1016/j.jdermsci.2011.10.008. Epub 2011 Nov 12.
During skin wounding and healing, skin homeostasis is interrupted. How the altered epithelial-mesenchymal interactions influence scar formation and epidermogenesis should be investigated using three-dimensional models that are similar to in vivo structures.
In this study, we assessed the effects of epithelial-mesenchymal interactions on myofibroblast differentiation and how myofibroblasts influence epidermogenesis using a human living skin equivalent (LSE) model.
We constructed a fibroblast-populated type I collagen gel upon which LSEs were formed by seeding with normal human keratinocytes. Samples of the collagen gel and LSEs were collected at different time points. Myofibroblast differentiation, epidermal differentiation, and proliferation status were investigated immunohistochemically. Several measures were taken to suppress α-smooth muscle actin (α-SMA) expression to determine the effects of myofibroblasts on epidermogenesis, including the addition of basic fibroblast growth factor or a transformation growth factor-β (TGF-β) kinase inhibitor to the culture medium and the inclusion of an amniotic membrane (AM) in the dermal matrix.
The myofibroblast/fibroblast ratio in the fibroblast-populated collagen gel kept rising during culture. In the LSEs, most fibroblasts were α-SMA-negative, except for those along the dermal-epidermal junction. The suppression of α-SMA expression enhanced epidermal differentiation and decreased TGF-β1 expression in the epidermis. The inhibition of TGF-β kinase completely suppressed α-SMA expression in the dermal matrix.
Epidermogenesis suppressed α-SMA expression in the fibroblast-rich dermal matrix, except near the dermal-epidermal junction. The α-SMA-positive cells at the dermal-epidermal junction contributed to the hyperproliferative phenotype of the epidermis. In contrast, the hyperproliferative epidermis expressed more TGF-β1, which is responsible for myofibroblast differentiation.
在皮肤创伤和愈合过程中，皮肤稳态被打断。改变的上皮-间充质相互作用如何影响瘢痕形成和表皮发生，应该使用类似于体内结构的三维模型进行研究。
本研究通过构建一个富含成纤维细胞的 I 型胶原凝胶，在其上种植正常人角质形成细胞，形成人活体皮肤等效物（LSE）模型，评估上皮-间充质相互作用对肌成纤维细胞分化的影响，以及肌成纤维细胞如何影响表皮发生。
我们构建了一个富含成纤维细胞的 I 型胶原凝胶，在其上种植正常人角质形成细胞，形成 LSE。在不同时间点收集胶原凝胶和 LSE 样本。免疫组织化学法检测肌成纤维细胞分化、表皮分化和增殖状态。为了确定肌成纤维细胞对表皮发生的影响，采取了几种措施抑制α-平滑肌肌动蛋白（α-SMA）的表达，包括在培养基中添加碱性成纤维细胞生长因子或转化生长因子-β（TGF-β）激酶抑制剂，以及在真皮基质中包含羊膜（AM）。
富含成纤维细胞的胶原凝胶中肌成纤维细胞/成纤维细胞的比例在培养过程中不断上升。在 LSE 中，大多数成纤维细胞呈α-SMA 阴性，除了沿真皮-表皮交界处的成纤维细胞。抑制α-SMA 表达增强了表皮分化，降低了表皮中 TGF-β1 的表达。TGF-β 激酶抑制剂完全抑制了真皮基质中α-SMA 的表达。
表皮发生抑制了富含成纤维细胞的真皮基质中的α-SMA 表达，除了靠近真皮-表皮交界处。真皮-表皮交界处的α-SMA 阳性细胞有助于表皮的过度增殖表型。相比之下，过度增殖的表皮表达更多的 TGF-β1，这是肌成纤维细胞分化的原因。
