The Regulation of Salivary Gland Regeneration by P2Y2 Nucleotide Receptors

描述(由申请人提供)：再生医学代表了治疗人类疾病的一种令人兴奋的新方法。各种组织的再生策略已经取得了进展，包括皮肤、角膜上皮、软骨、骨骼和膀胱。组织再生将代表着在治疗自身免疫性疾病干燥综合征和头颈部癌症的三次放射疗法中出现的唾液腺功能减退方面的重要进展。为了开发唾液腺在体内成功再生的技术，首先需要了解调控腺体发育的信号通路，这涉及腺泡的形成(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跨上皮阻力的极化上皮)。为了达到唾液腺组织再生的目的，我们的研究已经确定了一种在患病或受损的唾液腺中上调的P2Y2核苷酸受体(P2Y2R)。这些已发表的和初步的发现表明，P2Y2R激活调节信号通路，介导细胞的增殖和迁移，并维持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，这些基序促进了与复杂的信号网络的相互作用，这些信号网络涉及整合素、生长因子受体、基质金属蛋白酶、黏附分子和细胞骨架蛋白等调节细胞生长和分化的已知信号网络。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黏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这样的假设，即在受损或患病的唾液腺上皮中，P2Y2Rs的表达和激活促进了组织修复和再生。因此，我们建议利用腺泡形成的体外模型来证明P2Y2Rs的激活增强了再生反应。我们还将使用活体下颌下腺(SMG)导管结扎术来验证P2Y2Rs在受损唾液腺的恢复和再生中的作用。我们围绕几个特定的目标组织了这些假设。具体目标1将确定介导腺泡形成的P2Y2R信号通路。具体目标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。具体目标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单层的紧密连接组织。这项提案中的三个具体目标旨在确定P2Y2R上调和激活促进唾液腺再生的机制，以开发更好的治疗方法来修复受损的唾液腺。 与公共卫生相关：唾液腺因干燥综合征等疾病以及头颈部癌症的三次放射疗法而受损。我们的研究已经确定了细胞表面的一种受体，即P2Y2核苷酸受体(P2Y2R)，它在疾病或受损的唾液腺中上调。以往的研究表明，P2Y2R的激活调节细胞增殖、迁移和分化的信号通路，这有力地支持了这样的假说，即在受损或疾病的唾液腺中，P2Y2R的表达和激活可以促进组织修复和再生。

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.