The Regulation of Salivary Gland Regeneration by P2Y2 Nucleotide Receptors

描述（由申请人提供）：再生医学代表了一种令人兴奋的治疗人类疾病的新方法。各种组织的再生策略取得了进展，包括皮肤、角膜上皮、软骨、骨和膀胱。组织再生将代表唾液腺功能减退治疗的重要进展，唾液腺功能减退发生在自身免疫性疾病干燥综合征和头颈部癌症的3次放射治疗中。为了开发唾液腺在体内成功再生的技术，首先有必要了解调节腺体发育的信号通路，其中包括腺泡形成（即细胞增殖和迁移）和腺泡组织成功能性腺体结构（即细胞分化为具有高过上皮抗性的极化上皮）。为了实现唾液腺组织再生的目标，我们的研究已经确定了P2Y2核苷酸受体（P2Y2R）在患病或受损的唾液腺中上调。这些已发表的初步研究结果表明，P2Y2R的激活调节了介导细胞增殖和迁移的信号通路，并维持了正常唾液分泌所需的紧密连接。在过去的15年里，我们在P2Y2R中发现了新的结构基序，促进了与复杂信号网络的相互作用，这些信号网络调节细胞生长和分化，包括整合素、生长因子受体、基质金属蛋白酶、粘附分子和细胞骨架蛋白。这些信号网络使P2Y2R能够调节细胞反应，包括迁移和增殖，整合素/细胞外基质相互作用，细胞骨架重排以及细胞粘附分子和紧密连接蛋白的表达。总之，这些结果有力地支持了P2Y2Rs在受损或患病唾液腺上皮中的表达和激活促进组织修复和再生的假设。因此，我们建议利用体外腺泡形成模型来证明P2Y2Rs的激活可以增强再生反应。我们还将使用体内下颌腺（SMG）导管结扎来验证P2Y2Rs在受损唾液腺的恢复和再生中的作用。我们围绕几个具体目标组织了这些假设。特异性Aim 1将识别介导腺泡形成的P2Y2R信号通路。特异性目标2将研究整合素/P2Y2R相互作用在腺泡形成所需的细胞反应中的作用。特异性Aim 3将确定P2Y2R与肌动蛋白细胞骨架的相互作用是否调节Par-C10单层中的紧密连接组织。本提案中的3个特定目标旨在确定P2Y2R上调和激活增强唾液腺再生的机制，以开发更好的治疗方法来修复受损的唾液腺。

DESCRIPTION (provided by applicant): Regenerative medicine represents an exciting new approach in the treatment of human disease. Progress has been made in strategies for the regeneration of a variety of tissues including skin, corneal epithelium, cartilage, bone and bladder. Tissue regeneration would represent an important advancement in the treatment of salivary gland hypofunction that occurs in the autoimmune disease Sjogren's syndrome and as a result of 3-irradiation therapies for head and neck cancers. To develop techniques for the successful regeneration of salivary glands in vivo, it is first necessary to understand signaling pathways that regulate gland development, which involves acinar formation (i.e., cell proliferation and migration) and organization of acini into a functional gland structure (i.e., cell differentiation into a polarized epithelium with high transepithelial resistance). Towards the goal of regenerating salivary gland tissue, our studies have identified a P2Y2 nucleotide receptor (P2Y2R) that is upregulated in diseased or damaged salivary glands. These published and preliminary findings have demonstrated that P2Y2R activation regulates signaling pathways that mediate cell proliferation and migration and the maintenance of tight junctions required for normal saliva secretion. Over the past 15 years, we have identified novel structural motifs in the P2Y2R that facilitate interactions with complex signaling networks known to regulate cell growth and differentiation involving integrins, growth factor receptors, matrix metalloproteases, adhesion molecules and cytoskeletal proteins. These signaling networks enable the P2Y2R to regulate cellular responses, including migration and proliferation, integrin/extracellular matrix interactions, cytoskeletal rearrangements and the expression of cell adhesion molecules and tight junction proteins. Collectively, these results strongly support the hypothesis that expression and activation of P2Y2Rs in damaged or diseased salivary gland epithelium promote tissue repair and regeneration. Accordingly, we propose to utilize in vitro models of acinar formation to demonstrate that activation of P2Y2Rs enhances regenerative responses. We also will use in vivo submandibular gland (SMG) duct-ligation to validate a role for P2Y2Rs in the recovery and regeneration of damaged salivary glands. We have organized these hypotheses around several Specific Aims. Specific Aim 1 will identify P2Y2R signaling pathways that mediate acinar formation. Specific Aim 2 will investigate the role of integrin/P2Y2R interactions in cellular responses required for acinar formation. Specific Aim 3 will determine whether P2Y2R interaction with the actin cytoskeleton regulates tight junction organization in Par-C10 monolayers. The 3 Specific Aims in this proposal are designed to identify the mechanisms whereby P2Y2R upregulation and activation enhances salivary gland regeneration towards developing better therapies to repair damaged salivary glands. PUBLIC HEALTH RELEVANCE: Salivary glands are damaged by diseases such as Sjogren's syndrome and as a result of 3-irradiation therapies for head and neck cancers. Our studies have identified a receptor on the cell surface, the P2Y2 nucleotide receptor (P2Y2R) that is upregulated in diseased or damaged salivary glands. Previous studies have demonstrated that P2Y2R activation regulates signaling pathways that mediate cell proliferation, migration and differentiation, which strongly support the hypothesis that expression and activation of P2Y2Rs in damaged or diseased salivary glands can be used to promote tissue repair and regeneration.