PAR-1b in Integrin Localization and Laminin-111 Assembly in the Salivary Gland

描述(申请人提供)：几乎每个哺乳动物器官周围都有一种特殊形式的细胞外基质(ECM)，称为基底膜。在小鼠下颌下唾液腺(SMG)中，基底膜(BM)是组织发育的常用模型，基底膜(BM)位于最外层的上皮细胞之下，对组织组织和功能至关重要。我们最近发现，SMG周围BM蛋白的组织和表达受PAR-1b控制，PAR-1b是一种被广泛研究的极性蛋白。基底膜的表达减少或错误组装已被证明显著扰乱了相邻上皮细胞的极化。对地下室的破坏 膜在干燥综合征等疾病中也被发现。干燥综合征是一种自身免疫性疾病，影响外分泌腺，包括唾液腺和泪腺，减少分泌产物(唾液和泪液)，并导致患者的生活质量显著下降。在唾液腺中，唾液产物的定向分泌在很大程度上依赖于协调的细胞极性，而我们之前已经证明，细胞极性依赖于基底膜。我们还表明，为上皮细胞提供覆盖有基底膜蛋白LN-111的人工基质也可以增强细胞的极性。细胞的极性也依赖于细胞表面的受体，如整合素和营养不良聚糖，它们与骨髓直接接触，并经常传递由外向内的信号。我推测，PAR-1b调节细胞表面受体在基细胞表面的定位，进而调节基底膜中层粘连蛋白-111的组装。此外，我推测，在干燥综合征中，细胞极性的破坏可能会导致基底膜的破坏。本研究的主要目标是：(1)确定整合素β3、β6和β1和Dstroglan的定位是否受PAR-1b激酶活性的控制；(2)确定整合素β3、β6和β1和/或dystroglan是否可以调节层粘连蛋白-111在基底膜上的组装，从而调节涎腺上皮细胞的细胞极性；以及(3)确定这种已提出的与Sj？gren综合征影响的人和小鼠唾液腺基底膜退化相关的极性机制是否发生了变化。

DESCRIPTION (provided by applicant): Surrounding virtually every mammalian organ is a specialized form of extracellular matrix (ECM) known as the basement membrane. In the mouse submandibular salivary gland (SMG), a commonly used model for tissue development, the basement membrane (BM), underlying the outermost epithelial cells, is critical for tissue organization and function. We have recently shown that the organization and expression of BM proteins surrounding the SMG is controlled by PAR-1b, a widely studied polarity protein. Decreased expression or misassembly of the basement membrane has been shown to significantly disrupt the polarization of the adjacent epithelial cells. Disruption of the basement membrane has also been seen in diseases such as Sj¿gren's syndrome. Sj¿gren's syndrome is an autoimmune disease that affects the exocrine glands, including the salivary glands and the lacrimal glands, decreasing secretory products (saliva and tears) and causing significant decreases in the patient's quality of life. In the salivary gland, directional secretion of salivar products relies heavily on coordinated cellular polarity, which we have previously shown to be dependent on the basement membrane. We have also shown that providing epithelial cells with an artificial matrix coated with the basement membrane protein laminin-111 also enhances cellular polarity. Cellular polarity is also dependent upon cell surface receptors such as integrin and dystroglycan that make direct contacts with the BM and frequently relay outside-in signals. I hypothesize that PAR-1b regulates the localization of cell surface receptors to the basal cell surface, which in turn regulates the assembly of laminin-111 in the basement membrane. Further, I hypothesize that in Sj¿gren's syndrome, disruption of cellular polarity may lead to disruption of the basement membrane. The main goals of this research are: (1) to determine whether the localization of integrins ¿3, ¿6, and ¿1 and dystroglycan is under the control of PAR-1b kinase activity, (2) to determine whether integrin ¿3, ¿6, and ¿1 and/or dystroglycan regulate the assembly of laminin- 111 in the basement membrane and therefore the cellular polarity of the salivary epithelial cells, and (3) to determine whether there is a change in this proposed polarity mechanism associated with degraded the basement membrane in human and mouse salivary glands affected by Sj¿gren's syndrome.