Growth Factors and Gingival Fibrosis

描述（由申请人提供）：牙龈过度生长是特定药物的副作用，并以遗传和特发性形式（HGF）发生。这种情况会损害咀嚼，并使受影响的个体容易出现全身并发症。虽然牙龈过度生长的病变在临床上表现相似，但我们的研究表明，牙龈过度生长的分子和细胞特征随着病因的变化而变化。苯妥英诱导的牙龈过度生长和HGF病变是高度纤维化的，含有高水平的结缔组织生长因子（CTGF）；而环孢素A诱导的过度生长较少纤维化，且含有少量的CTGF；硝苯地平诱导的牙龈过度生长在各方面起中介作用。最近的研究已经确定了组织特异性途径，提供了纤维化牙龈组织中CTGF表达升高的机制，以及潜在的治疗策略。此外，我们已经发表的证据表明，CTGF通过α -6和β -1整合素促进细胞外基质沉积。初步数据表明，上皮-间质转化（EMT）过程有助于所有形式的牙龈过度生长；一种至关重要的基质金属蛋白酶（MMP-13）在纤维化形式的牙龈过度生长中被下调。因此，提出了两个目标。在Aim 1中，我们将确定EMT发生在体内所有形式的人类牙龈过度生长中，我们将评估EMT抑制剂在原代牙龈上皮细胞和成纤维细胞的体外研究中阻止异常进展的机制。目的2提出评估CTGF调节细胞外胶原加工酶和基质金属蛋白酶（MMP-13）从而增加细胞外基质净积累的假设。拟议的研究将确定CTGF刺激的信号转导途径，并调节导致细胞外基质沉积增加的下游基因。这些研究利用了我们最近发现的抑制ctgf依赖性细胞外基质沉积的肽。提出的实验方法利用人牙龈过度生长组织的原位分析，以及原代培养的单层和三维结构的人牙龈上皮细胞。研究将确定新的细胞和分子途径，有助于牙龈过度生长。研究结果将与口腔和非口腔组织的纤维化相关，其中CTGF是一个促成因素，从而有可能确定各种组织的新治疗策略。

DESCRIPTION (provided by applicant): Gingival overgrowth is a side effect of specific medications, and occurs as inherited and idiopathic forms (HGF). The condition impairs mastication, and predisposes affected individuals to systemic complications. Although gingival overgrowth lesions appear clinically similar, our studies have shown that the molecular and cellular features of gingival overgrowth vary as a function of the cause. Phenytoin-induced gingival overgrowth and HGF lesions are highly fibrotic and contain high levels of connective tissue growth factor (CTGF); whereas cyclosporin A induced overgrowth is less fibrotic, and contains low amounts of CTGF; and nifedipine-induced gingival overgrowth is intermediated in all respects. Recent studies have identified tissue specific pathways that provide the mechanism for elevated CTGF expression in fibrotic gingival tissues, and potential therapeutic strategies. In addition, we have published evidence that CTGF promotes extracellular matrix deposition via alpha-6 and beta-1 integrins. Preliminary data suggest that the process of epithelial- mesenchymal transition (EMT) contributes to all forms of gingival overgrowth; and that a critically important matrix metalloproteinase (MMP-13) is down regulated in fibrotic forms of gingival overgrowth. Thus, two aims are proposed. In Aim 1 we will establish that EMT occurs in all forms of human gingival overgrowth in vivo, and we will evaluate the mechanism of inhibitors of EMT to block progression of abnormalities in in vitro studies of primary gingival epithelial cells and fibroblasts. Aim 2 proposes to evaluate the hypothesis that CTGF regulates extracellular collagen processing enzymes and a matrix metalloproteinase (MMP-13), thereby increasing net extracellular matrix accumulation. Proposed studies will determine CTGF stimulated signal transduction pathways and regulated downstream genes that lead to increased extracellular matrix deposition. These studies take advantage of a peptide that inhibits CTGF-dependent extracellular matrix deposition that we have recently identified. The proposed experimental approach utilizes in situ analyses of human gingival overgrowth tissues, and primary cultured human gingival epithelial cells grown in monolayer and three dimensional configurations. Studies will identify novel cellular and molecular pathways that contribute to gingival overgrowth. Findings will have relevance to fibrosis in both oral and non-oral tissues in which CTGF is a contributing factor, thus potentially identifying new therapeutic strategies in various tissues.