P2Y2R MEDIATED IMMUNE RESPONSES IN SALIVARY GLAND DYSFUNCTION

描述（由申请人提供）：干燥综合征（SS）是一种自身免疫性疾病，以泪腺和唾液腺的炎症和破坏为特征，导致口干症。SS的外分泌腺功能减弱通常与组织的淋巴细胞浸润和促炎细胞因子如白细胞介素-1 β (il -1 β)、白细胞介素-6 （IL-6）、肿瘤坏死因子- α (TNFalpha)和干扰素- γ (IFNgamma)的产生增加有关。我们已经证明G蛋白偶联的P2Y2核苷酸受体（P2Y2R）在唾液腺上皮损伤或应激反应中上调。P2Y2R在应激唾液上皮中的作用尚未确定，然而，我们实验室的研究表明，在血管内皮中，P2Y2R上调的激活增加了VCAM-1的表达，促进了单核细胞的结合和跨内皮迁移。初步结果表明，唾液上皮P2Y2Rs的激活上调了VCAM-1的表达，刺激淋巴细胞粘附，这是细胞因子释放的一个来源。此外，我们已经获得证据表明，唾液腺中P2Y2R的激活增强了参与唾液上皮可溶性细胞因子释放的金属蛋白酶的活性。这些数据有力地支持了一个假设，即唾液腺细胞中P2Y2R的表达和激活通过调节促进免疫细胞与唾液腺上皮结合的粘附分子的表达，以及通过激活参与破坏上皮完整性的细胞因子释放的金属蛋白酶，有助于SS的上皮功能障碍。因此，拟议的研究将利用极化大鼠腮腺（Par-C10）单层来评估P2Y2Rs在促进淋巴细胞粘附的特异性粘附分子表达（specific Aim 1）和激活产生促炎细胞因子的金属蛋白酶（specific Aim 2）中的作用。然后，将评估相关细胞因子对经上皮阴离子分泌（l(sc)）以及调节唾液腺离子转运和上皮完整性的上皮细胞紧密连接蛋白的表达和磷酸化的影响（Specific Aim 3）。这些研究可能会导致更好的治疗策略，以尽量减少导致SS患者口干的唾液腺自身免疫相关功能障碍。

DESCRIPTION (provided by applicant): Sjogren's syndrome (SS) is an autoimmune disorder characterized by inflammation and destruction of lacrimal and salivary glands leading to xerostomia. The diminished function of exocrine glands in SS is often associated with lymphocytic infiltration of the tissue and increased production of pro- inflammatory cytokines such as interleukin-1beta (IL-1beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNFalpha) and interferon-gamma (IFNgamma). We have shown that the G protein-coupled P2Y2 nucleotide receptor (P2Y2R) is up-regulated in response to damage or stress in salivary gland epithelium. The role of the P2Y2R in stressed salivary epithelium has not been determined, however, studies in our lab have shown that in vascular endothelium the activation of up-regulated P2Y2Rs increases the expression of VCAM-1 and promotes the binding and transendothelial migration of monocytes. Preliminary results indicate that activation of P2Y2Rs in salivary epithelium up-regulates VCAM-1 expression and stimulates lymphocyte adherence, a source of cytokine release. Moreover, we have obtained evidence that P2Y2R activation in salivary glands enhances activity of metalloproteases that are involved in the release of soluble cytokines from the salivary epithelium. These data strongly support a hypothesis that P2Y2R expression and activation in salivary gland cells contributes to epithelial dysfunction in SS by regulating the expression of adhesion molecules that promote the binding of immune cells to salivary epithelium and by activating metalloproteases involved in the release of cytokines that compromise epithelial integrity. Therefore, proposed studies will utilize polarized rat parotid (Par-C10) monolayers to evaluate the role of P2Y2Rs in the expression of specific adhesion molecules that promote lymphocyte adherence (Specific Aim 1) and to the activation of metalloproteases that generate pro-inflammatory cytokines (Specific Aim 2). Then, the effects of relevant cytokines will be evaluated with respect to transepithelial anion secretion (l(sc)) and the expression and phosphorylation of epithelial cell tight junction proteins that regulate ion transport and epithelial integrity in salivary glands (Specific Aim 3). These studies may lead to better therapeutic strategies for minimizing autoimmune-associated dysfunction of salivary gland that contributes to xerostomia in patients with SS.