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，其特征是泪腺和唾液腺的炎症和破坏，导致口干。SS患者外分泌腺功能的降低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（TNF α）和干扰素-γ（IFN γ）的产生增加有关。我们已经表明，G蛋白偶联的P2 Y2核苷酸受体（P2 Y2 R）上调，在唾液腺上皮细胞的损伤或应力。P2 Y2 R在应激唾液腺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，上调的P2 Y2 R的激活增加了VCAM-1的表达，并促进单核细胞的结合和跨内皮迁移。初步结果表明，激活P2 Y2 Rs在唾液腺上皮上调VCAM-1的表达，并刺激淋巴细胞粘附，细胞因子释放的来源。此外，我们已经获得的证据表明，P2 Y2 R在唾液腺中的激活增强了参与从唾液上皮释放可溶性细胞因子的金属蛋白酶的活性。这些数据有力地支持了一个假设，即P2 Y2 R的表达和激活唾液腺细胞有助于上皮功能障碍SS通过调节粘附分子的表达，促进免疫细胞的结合唾液上皮和激活金属蛋白酶参与细胞因子的释放，损害上皮的完整性。因此，拟定的研究将利用极化大鼠腮腺（Par-C10）单层来评价P2 Y2 Rs在促进淋巴细胞粘附的特异性粘附分子表达（特异性目的1）和产生促炎细胞因子的金属蛋白酶激活（特异性目的2）中的作用。然后，将评价相关细胞因子对跨上皮阴离子分泌（I（sc））以及调节唾液腺中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（具体目标3）。这些研究可能会导致更好的治疗策略，以尽量减少自身免疫相关的功能障碍的唾液腺，有助于口腔干燥症患者的SS。

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.