EPITHELIAL ACETYLCHOLINE IN ORAL BIOLOGY AND PATHOLOGY

我们需要资金来支持我们正在进行的识别分子机制的研究。 乙酰胆碱及其药理类似物和烟草制品对口腔角质形成细胞的影响。 角质形成细胞出生和死亡的连续周期是一个自我维持的过程，部分受局部控制。 荷尔蒙通过信号通路偶联每种类型的ACh受体来调节 特殊的细胞功能。游离细胞递质ACh以与生理相关的浓度存在于 上消化道的衬里上皮。OKC表达ACh合成酶和降解酶， 以及烟碱型和毒鼠型ACh受体。一种通过烟碱调节细胞的新范式 ACh受体(NAChRs)是在对胆碱能蛋白的研究中发现的，这种蛋白被称为surp(分泌型) 哺乳动物Ly-6/尿激酶型纤溶酶原激活物受体相关蛋白)-1和-2。初步结果 提示slurp-1和slurp-2对角质形成细胞的增殖、凋亡和分化具有调节作用。多数 重要的是，口香糖和专业的尼古丁拮抗剂可以部分地消除尼古丁衍生的能力。 亚硝胺4-(methylnitrosamino)-1-(3¿pyridyl)-1-butanone和N‘-亚硝基烟碱 以引起不朽的OKC的转变。我们将测试以下工作假设：1) NNK的病理生物学效应主要是通过α7和/或α9 nAChR(S)介导的，而NNN则主要通过α3制造的nAChR(S)介导；2)唾液蛋白可以防止口腔细胞亚硝胺依赖的转化 体内和体外，并取消烟草/尼古丁依赖的角质形成细胞周期、生长和 3)SLULP-1主要与NNK竞争结合同源五聚体nAChR(S)和 Surp-2与NNN在异五聚体nAChR(S)的结合位点上，这两个Surp都干扰 亚硝胺诱导nAChR信号转导。具体目标是确定：1)角质形成细胞的作用 NAChRs在介导烟草亚硝胺的病理生物学效应中的作用；2)slurp-1和-2在 OKC对烟草毒性的生理保护；3)受体介导的信号机制 调节Surp-1和-2对OKC的作用。

Funding is requested to support our ongoing studies toward identification of molecular mechanisms mediating effects of acetylcholine (ACh), its pharmacologic congeners and tobacco products on oral keratinocytes (OKC). The continuous cycle of keratinocyte birth and death is a self-sustained process controlled, in part, by the local hormone ACh through the signaling pathways that couple each type of ACh receptors to regulation of a particular cell function. Free cytotransmitter ACh is present in physiologically-relevant concentrations in the epithelium lining the upper digestive tract. OKC express both the ACh synthesizing and degrading enzymes, and both nicotinic and muscarinic classes of ACh receptors. A novel paradigm of cell regulation via nicotinic ACh receptors (nAChRs) has been discovered in studies of the cholinergic proteins termed SLURP (secreted mammalian Ly-6/urokinase plasminogen activator receptor-related protein)-1 and -2. Preliminary results indicate that SLURP-1 and -2 regulate keratinocyte proliferation, apoptosis and differentiation. Most importantly, SLURPs and professional nicotinic antagonists can abolish, in part, the abilities of the nicotinederived nitrosamines 4-(methylnitrosamino)-1-(3¿pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) to cause transformation of immortalized OKC. We will test the following working hypotheses: 1) the pathobiologic effect of NNK is mediated predominantly via alpha7 and/or alpha9 nAChR(s), and that of NNN¿via alpha3-made nAChR(s); 2) SLURP proteins can prevent nitrosamine-dependent transformation of oral cells both in vivo and in vitro, and abolish tobacco/nicotine-dependent alterations in the keratinocyte cell cycle, growth and differentiation; and 3) SLURP-1 competes mainly with NNK for binding to the homopentameric nAChR(s) and SLURP-2¿with NNN at the binding site of heteropentameric nAChR(s), and both SLURPs interfere with the nitrosamine-induced nAChR signaling. The Specific Aims will be to determine: 1) the role of keratinocyte nAChRs in mediating the pathobiologic effects of tobacco nitrosamines; 2) the roles for SLURP-1 and -2 in the physiologic protection of OKC from tobacco toxicity; and 3) the receptor-mediated signaling mechanisms mediating SLURP-1 and -2 actions on OKC.