P2Y2R MEDIATED IMMUNE RESPONSES IN SALIVARY GLAND DYSFUNCTION

描述(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患者外分泌腺功能下降通常与组织中淋巴细胞的渗透和促炎细胞因子的产生增加有关，如IL-1β(IL-1β)、IL-6(IL-6)、肿瘤坏死因子-α(TNFpha)和干扰素-γ(IFN-γ)。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时上调。P2Y2R在应激唾液上皮中的作用尚未确定，但我们实验室的研究表明，在血管内皮细胞中，上调的P2Y2R的激活增加了VCAM-1的表达，并促进了单核细胞的结合和跨内皮迁移。初步结果表明，唾液上皮中P2Y2Rs的激活上调了VCAM-1的表达，并刺激了淋巴细胞黏附，这是细胞因子释放的来源。此外，我们获得的证据表明，唾液腺中的P2Y2R激活增强了参与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种假设，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上皮结合的黏附分子的表达，以及通过激活参与细胞因子释放的金属蛋白酶来影响上皮完整性，从而导致SS的上皮功能障碍。因此，建议的研究将利用极化的大鼠腮腺(PAR-C10)单层来评估P2Y2Rs在促进淋巴细胞黏附的特定黏附分子的表达(特定目标1)和产生促炎细胞因子的金属蛋白酶的激活(特定目标2)中的作用。然后，将评估相关细胞因子对跨上皮阴离子分泌的影响(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(特定目标3)。这些研究可能导致更好的治疗策略，将导致SS患者口干症的唾液腺自身免疫相关功能障碍降至最低。

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.