SALIVARY MUCIN SYNTHESIS, PROCESSING AND SECRETION

这项建议的一个主要目的是在体内标准化和描述 小鼠颌下腺粘蛋白的刺激-分泌-合成周期。 该系统旨在提供对控制和合成的洞察 负责每日外分泌补充的过程 唾液腺中的蛋白质。据推测，通过澄清 正常的事件流程，就有可能开始了解一些 各种形式的唾液腺功能障碍。描述了用于获得 不同温度下粘蛋白核心蛋白的合成和降解速率 周期的各个阶段。粘蛋白低聚糖组装的速率和顺序 也将被确定。一种确定以下机制的策略 描述了合成阶段的激活以及可能的配合 将测试翻译和糖基化过程之间的关系。决赛 这一阶段的项目将检查以下方面的效果 周期中不同的刺激物。 我们将把我们最近对幼年到中年的研究扩展到衰老的小鼠 小鼠，表明粘蛋白寡糖组成稳定 通过慢性异丙肾上腺素治疗。这一阶段研究的目的是 是确定粘蛋白的碳水化合物组成是否在老年人中变化更大 如果异丙肾上腺素治疗可以减少这种情况 变种。慢性毛果芸香碱治疗的效果将在 相同的年龄段。 不同促分泌剂与粘蛋白关系的研究 唾液中的浓度将在小鼠身上重复并延长 固有变异已大大减少的种群。 已采取措施为这一人群提供服务并采取其他方法 正在接受调查。在之前的研究中，超过60倍的 观察刺激后唾液中粘蛋白浓度的变化范围 相同剂量的毛果芸香碱在不同动物体内的分泌物 普通实验室人口。我们计划比较不同方案的效果 剂量，但不能预测成功，除非固有的差异被减少。 最后，我们提出的证据表明，粘蛋白经历了 低聚糖的加工步骤是分泌。两个协议将对此进行测试 有可能。如果处理被确认，我们将确定哪一类 寡糖受到影响，这是如何影响细胞内唾液酸的 以及所涉及的机制。

A key purpose of this proposal is to standardize and describe in vivo the stimulus-secretion-synthesis cycle of a mouse submandibular gland mucin. This system is intended to provide insight into the control and synthesis processes which are responsible for the diurnal replenishment of exocrine proteins in the salivary glands. It is postulated that by clarifying the normal flow of events, it will be possible to begin to understand some forms of salivary gland dysfunction. Protocols are described for obtaining rates of synthesis and degradation of the mucin core protein at different stages of the cycle. Rates and sequence of mucin oligosaccharide assembly will also be ascertained. A strategy for identifying the mechanism for activation of the synthesis phase is described and possible coordination between translation and glycosylation processes will be tested. The final phase of this part of the project will be to examine the effects of different stimuli on the cycle. We will extend to senescent mice our recent study with young to mid-adult mice which indicated that mucin oligosaccharide composition was stabilized by chronic isoproterenol treatment. The intent of this phase of the study is to determine if the carbohydrate composition of mucin varies more in old mice than in young and if isoproterenol treatment can reduce this variation. The effects of chronic pilocarpine treatment will be tested in the same age groups. A study of the relationship of different secretagogues to mucin concentrations in saliva will be repeated and extended in a mouse population in which inherent variation has been reduced substantially. Steps have been taken to provide this population and additional approaches are under investigation. In the previous study, a greater than 60-fold range of mucin concentrations in saliva was observed following stimulation of secretion with the same dosage of pilocarpine in different animals of a regular laboratory population. We plan to compare effects of different dosages but do not predict success unless the inherent variation is reduced. Finally, we present evidence suggesting that mucin undergoes an oligosaccharide processing step at secretion. Two protocols will test this possibility. If processing is confirmed, we will determine which class of oligosaccharides is affected, how this impacts intracellular sialic acid and the mechanisms involved.