Prolactin--Autocrine/paracrine factor in lacrimal gland

干眼是一种常见的问题，严重影响生活质量和潜在的威胁视力的并发症。它通常是由于免疫相关过程引起的泪液不足，如干燥综合征，或与衰老和各种生理状态相关的激素变化所致。催乳素似乎是影响泪腺的一个关键荷尔蒙。对人类受试者、切除垂体的大鼠、转基因小鼠和原代培养的腺泡细胞的研究表明，即使血清浓度在正常值范围内，催乳素也会损害泪液功能。此外，损害泪腺功能的催乳素的来源可能是泪腺本身。泪腺表达催乳素mRNA和蛋白质，这可能是一种自分泌或内分泌因子，在某些情况下可能会干扰分泌。该项目将在原代培养中使用泪腺泡细胞来回答以下问题：1.局部表达的催乳素是否作为一种自分泌/内分泌因子，在正常浓度下支持分泌功能，而在过高浓度时损害分泌功能？将使用中和抗体和反义试剂将局部表达的催乳素的作用降至最低。表达结构将被用来过度表达催乳素。将评估腺泡细胞形态、氨基甲胆碱诱导的蛋白分泌、聚合免疫球蛋白受体的表达以及离子转运蛋白的表达，以了解与催乳素表达变化相关的变化。2.在其他细胞中具有抑制作用的改变形式的催乳素(16 kDa和磷酸化24 kDa)是否会抑制泪液分泌功能？过度表达和添加形式的效果将在特定目标1.3中进行测试。泪液催乳素是否作为一种旁分泌因子参与自身免疫激活？反义试剂和表达载体将用于抑制或增强腺泡细胞催乳素的表达，并将测试修饰后的细胞在混合细胞反应中促进自体淋巴细胞增殖的能力。这项工作将促进我们对泪道生理学的重要机制的理解，并将对目前正在进行的其他研究的方向产生直接的影响。它还有可能刺激许多远远超出其目前范围的工作，包括旨在确定不同病因的泪液缺乏患者亚群的流行病学研究，然后设计适当的、高度特异的治疗方法。

Dry eye is a common problem with a severe impact on the quality of life and potential vision-threatening complications. It often results from lacrimal insufficiency caused by immune-related processes, as in Sjogren's syndrome, or by hormone changes associated with aging and various physiological states. One critical hormonal influence on the lacrimal glands appears to be prolactin. Studies with human subjects, hypophysectomized rats, transgenic mice, and acinar cells in primary culture indicate that prolactin can impair lacrimal function, even at serum concentrations within the range of normal values. Moreover, the source of the prolactin that impairs lacrimal gland function may be the lacrimal glands themselves. The lacrimal glands express prolactin mRNA and protein, which may act as an autocrine or intracrine factor that in some circumstances may interfere with secretion. This project will use lacrimal acinar cells in primary culture to answer the following questions: 1. Does locally expressed prolactin act as an autocrine/intracrine factor that supports secretory functions at normal concentrations and impairs them at excessive concentrations? Neutralizing antibodies and antisense reagents will be used to minimize actions of locally expressed prolactin. Expression constructs will be used to overexpress prolactin. Acinar cell morphology, carbachol-induced protein secretion, expression of polymeric immunoglobulin receptors, and expression of ion transport proteins will be evaluated for changes related to altered prolactin expression. 2. Do altered forms of prolactin (16 kDa and phosphorylated 24 kDa) that have inhibitory effects in other cells inhibit lacrimal secretory function? The effects of overexpressed and added forms will be tested as in Specific Aim 1. 3. Does lacrimal prolactin act as a paracrine factor contributing to autoimmune activation? Antisense reagents and expression constructs will be used to suppress or enhance acinar cell prolactin expression, and the modified cells will be tested for their ability to promote proliferation of autologous lymphocytes in mixed cell reactions. This work will advance our understanding of significant mechanisms in lacrimal physiology, and it will have immediate implications for the direction of other studies now in progress. It also has the possibility of stimulating much work well beyond its present scope, including epidemiological studies aimed at identifying sub-populations of lacrimal deficiency patients with different etiologies, followed by design of appropriate, highly specific therapies.