PEPTIDE HORMONE TARGETING IN SALIVARY GLAND CELLS

唾液腺表达的外源性分泌肽具有潜在的 在调节唾液流量和组成方面的临床重要性，或 作为口腔和胃肠道中的治疗肽。 腺病毒介导的基因转移到唾液腺最近已被 证明，表明治疗性肽的表达， 唾液腺和唾液在临床上是可行的。控制如何 治疗性肽的释放对于临床成功是重要的， 这种方法。理想地，可以调节这些肽的释放 根据它们的治疗作用， 组成性分泌或通过储存在 分泌颗粒目标定位或分类所需的信号 外分泌细胞中调节分泌途径的肽， 知道的本研究的长期目标是确定 肽靶向所需的氨基酸序列和机制 激素调节外分泌细胞的分泌途径。外分泌 内分泌细胞表达调节性和组成性分泌 通路调节途径与组成性途径不同， 途径，共同的所有真核细胞，通过较慢的释放时间（在 缺乏刺激），分泌蛋白的细胞内储存， 对促分泌素有反应的刺激分泌。 调节型分泌 蛋白质，包括消化酶和肽激素是靶向的， 排序到trans-Golgi网络中的调节途径或成熟 分泌颗粒似乎存在一种通用的排序机制， 不同的内分泌细胞，因为外来的内分泌蛋白是正确的， 在转染的内分泌细胞中分选。分类机制， 外分泌细胞的功能尚不清楚。心房肽激素 利钠因子（ANF）在唾液腺腺泡细胞中表达， 因此，代表了这些研究的生理学相关模型。在 在本提案中，我们将测试proANF被分类为 外分泌细胞中的调节途径，然后阐明分选 需要信号。提出了以下具体目标：（1）确定是否 唾液腺来源的细胞系表现出受调节的分泌。（二） 确定proANF是否被分选到受调节的分泌途径， 外分泌细胞3)确定前心钠素的氨基酸序列， 在将蛋白质分选到受调节的分泌途径中的作用。四、 确定proANF的分类机制：确定分类是否 需要信号来聚集proANF或与 细胞分选受体

Exogenous secretory peptides expressed in salivary glands are of potential clinical importance in the regulation of salivary flow and composition, or as therapeutic peptides in the mouth and gastrointestinal tract. Adenovirus-mediated gene transfer to salivary glands has recently been demonstrated, suggesting that the expression of therapeutic peptides in salivary glands and saliva is clinically feasible. Controlling how therapeutic peptides are released is important for the clinical success of this approach. Ideally, the release of such peptides can be regulated according to their therapeutic role so that they are released either by constitutive secretion or by regulated secretion of peptides stored in secretory granules. The signals required for targeting or sorting of peptides to the regulated secretory pathway in exocrine cells are not known. The long term goal of the present research is to determine the amino acid sequence(s) and mechanisms required for targeting of peptide hormones to the regulated secretory pathway in exocrine cells. Exocrine and endocrine cells express both a regulated and a constitutive secretory pathway. The regulated pathway is distinguished from the constitutive pathway, common to all eukaryotic cells, by slower release times (in the absence of stimulation), intracellular storage of secretory proteins and stimulated secretion in response to secretogogues. Regulated secretory proteins, including digestive enzymes and peptide hormones are targeted or sorted to the regulated pathway in the trans-Golgi network or maturing secretory granules. It appears that a common sorting mechanism exists for different endocrine cells since foreign endocrine proteins are correctly sorted in transfected endocrine cells. The sorting mechanisms that function in exocrine cells are not known. The peptide hormone atrial natriuretic factor (ANF) is expressed in salivary gland acinar cells and, thus, represents a physiologically relevant model for these studies. In the present proposal we will test the hypothesis that proANF is sorted to the regulated pathway in exocrine cells and then elucidate the sorting signal required. The following specific aims are proposed: 1) Determine if salivary gland-derived cell lines exhibit regulated secretion. 2) Determine if proANF is sorted to the regulated secretory pathway in exocrine cells. 3) Identify the amino acid sequences of proANF that play a role in sorting of the protein to the regulated secretory pathway. 4) Determine the sorting mechanism for proANF: Determine if the sorting signals are required for aggregation of proANF or interaction with a cellular sorting receptor.