Characterization of the regulation of corneal epithelial and stromal functions in order to further the development of an artificial cornea

1)研究了生长因子和细胞因子对培养的人角膜上皮细胞和角膜基质细胞增殖、凋亡和细胞间通讯的调节作用。在上皮细胞中，肝细胞生长因子、胰岛素、胰岛素样生长因子-1、胰岛素样生长因子-2和表皮生长因子均可刺激细胞增殖，抑制硝普钠诱导的细胞凋亡，并诱导AKT的激活，而转化生长因子-β1和转化生长因子-β2抑制细胞增殖，但对细胞凋亡和AKT活性无影响。在角质形成细胞中，PDGF、胰岛素、IGF-1、IGF-2和EGF均刺激细胞增殖，抑制细胞凋亡，并诱导Akt激活，而碱性成纤维细胞生长因子、KGF、NGF和HGF刺激细胞增殖，但不影响细胞凋亡和Akt活性。炎性细胞因子肿瘤坏死因子-α和Th2型细胞因子IL-4和IL-13下调上皮屏障功能。肿瘤坏死因子-α还通过角质形成细胞的缝隙连接抑制细胞间的通讯2)我们发现Rho的活性上调…3)转录因子NF-κB被证明是IL-1诱导角膜上皮细胞降解胶原所必需的。地塞米松和雷公藤内酯醇均可抑制IL-1的这种作用。4)将角膜基质细胞培养在含有多种细胞外基质蛋白的胶原凝胶中，观察细胞的收缩能力。在含有角质形成细胞的胶原凝胶中加入纤维连接蛋白，以时间和浓度依赖的方式诱导显著的凝胶收缩。纤维连接蛋白还能诱导细胞伸展，并在凝胶包埋的角质形成细胞中形成肌动蛋白应激纤维。5)我们研究了氧浓度对细胞功能的影响。高氧促进角膜上皮损伤愈合，低氧抑制ZO-1表达，破坏角膜上皮细胞屏障功能。高氧还抑制角膜上皮细胞的增殖，而低氧和高氧均抑制角膜上皮细胞的增殖。较少

1)Regulation of cellular proliferation, apoptosis, and intercellular communication by growth factors and cytokines has been investigated in cultured human corneal epithelial cells and keratocytes. In epithelial cells, HGF, insulin, IGF-1,IGF-2, and EGF each stimulated cell proliferation, inhibited the induction of apoptosis by sodium nitroprusside, and elicited the activation of Akt, whereas TGF-β1 and TGF-β2 inhibited cell proliferation but had no effect on apoptosis or Akt activity. In keratocytes, PDGF, insulin, IGF-1,IGF-2, and EGF each stimulated cell proliferation, inhibited the induction of apoptosis, and elicited the activation of Akt, whereas basic FGF,KGF,NGF, and HGF stimulated cell proliferation but did not affect apoptosis or Akt activity. The inflammatory cytokine TNF-α and the Th2 cytokines IL-4 and IL-13 down-regulated epithelial barrier function. TNF-α also inhibited intercellular communication by gap junctions in keratocytes.2)We showed that the activity of Rho was up … More -regulated in corneal epithelia cells cultured on fibronectin and that Rac activity was increased in these cells by culture on laminin.3)The transcription factor NF-κB was shown to be required for IL-1-induced degradation of collagen by keratocytes. Dexamethasone and triptolide each inhibited this effect of IL-1.4)The contractility of keratocytes was examined by culture of the cells in a collagen gel in the presence of various other extracellular matrix proteins. The addition of fibronectin to collagen gels containing keratocytes induced marked gel contraction in a time- and concentration-dependent manner. Fibronectin also induced cell spreading and the formation of actin stress fibers in the gel-embedded keratocytes.5)We investigated the effects of oxygen concentration on cellular functions. Hyperoxia stimulated corneal epithelial wound healing, whereas hypoxia inhibited ZO-1 expression and disrupted the barrier function of corneal epithelial cells. Hyperoxia also inhibited the proliferation of epithelial cells, whereas both hypoxia and hyperoxia inhibited keratocyte proliferation. Less