Cell junction and nuclear forces as mediators of epithelial cell homeostasis

排列在体内腔和体外的上皮细胞以单层的形式存在于组织中， 多层单元格和三维管道/管道结构。正确的形成和动态平衡 上皮细胞对组织和器官的功能至关重要；上皮细胞的失调与上皮细胞 屏障丧失(包括败血症)，伤口愈合缺陷，以及癌症的发展和进展。虽然 对上皮细胞的机械力已被证明影响细胞的组织、增殖和 在迁移过程中，细胞对力做出反应的机制尚不清楚。这项提案考察了 细胞-细胞连接和核骨架-细胞骨架(LINC)核连接物中蛋白质间的作用力 复合体作为上皮细胞动态平衡的介体。强大的细胞-细胞连接对细胞的完整性至关重要 上皮细胞，包括细胞的凝聚力、屏障功能和抵抗机械应力的能力。连接点的丢失是 与上皮功能障碍有关，包括炎症引起的通透性增加和上皮细胞 间充质转化(EMT)。尽管细胞间黏附的形成已被证明是至关重要的 细胞增殖、迁移和组织组织的调节者，对细胞与细胞如何连接知之甚少 力量促成了这些过程。除了改变结合力之外，外部作用力也可能 在细胞内传播，穿过细胞骨架，进入细胞器。原子核，这是物理上的 通过LINC复合体连接到细胞骨架，很可能受到外力的影响。核力量已经 被建议用来调节原子核的几何形状和原子核的位置，这两者在不同的 疾病，包括癌症。这项米拉计划的主要研究目标是研究力量如何跨越 细胞-细胞连接蛋白和核LINC复合体调控上皮细胞的增殖、迁移、连接 稳定性和3D组织。基于FRET的新型张力生物传感器将被用于直接测量力 在细胞-细胞连接处跨越紧密连接、粘连连接和桥粒，以及特定的亚型 在LINC建筑群的奈斯普林。连接或核力受到干扰的治疗或突变体将是 用于评估力在调节上皮过程中的因果性质。这项提议的另一个目标是 为了确定细胞-细胞连接、细胞-基质粘连和细胞核之间的力之间的关系 LINC复合体，确定力是如何从细胞的一个区域传递到另一个区域的。这 对细胞-细胞、细胞-基质和核力的综合研究将极大地促进对 上皮动态平衡，包括伤口修复、炎症和上皮组织的过程 发展和组织，以及上皮性疾病，包括癌症、纤维化和慢性 发炎。结合力和核力量可能代表着控制扩散的普遍机制， 移民和组织；因此，这项研究的结果可能也与大量非 上皮细胞和组织。

Epithelial cells, which line both the inside cavities and outside of the body, exist in tissues as monolayers, multilayers of cells, and three dimensional tube/duct structures. Proper formation and homeostasis of the epithelium is critical for tissue and organ function; dysregulation of the epithelium is associated with epithelial barrier loss (including sepsis), defective wound healing, and development and progression of cancer. Although mechanical forces on epithelial cells have been shown to influence cell organization, proliferation, and migration, it is not known the mechanisms by which cells respond to force. This proposal examines the role of force across proteins in both cell-cell junctions and the nuclear linker of nucleoskeleton to cytoskeleton (LINC) complex as mediators of epithelial homeostasis. Strong cell-cell junctions are critical to the integrity of the epithelium, including cell cohesion, barrier function, and ability to resist mechanical stress. Loss of junctions is associated with epithelial dysfunction including inflammatory-induced increases in permeability and epithelial to mesenchymal transition (EMT). Although formation cell-cell adhesions have been shown to be critical regulators of cell proliferation, migration, and tissue organization, very little is known how cell-cell junction forces contribute to these processes. In addition to altering junction forces, externally applied forces are likely transmitted inside the cell, across the cytoskeleton, and onto organelles. The nucleus, which is physically connected to the cytoskeleton by the LINC complex, is likely affected by external forces. Nuclear forces have been suggested to regulate nuclear geometry and nuclear positioning, both of which are altered in a variety of diseases, including cancer. The major research goals of this MIRA proposal are to examine how forces across cell-cell junction proteins and the nuclear LINC complex regulate epithelial proliferation, migration, junction stability, and 3D organization. Novel FRET-based tension biosensors will be used to directly measure forces across tight junctions, adherens junctions, and desmosomes at cell-cell junctions and specific isoforms of nesprin at the LINC complex. Treatments or mutants for which junction or nuclear force is perturbed will be used to assess the causal nature of force in regulation of the epithelium. An additional goal of this proposal is to identify the relationship between forces across cell-cell junctions, cell-matrix adhesions, and the nuclear LINC complex, identifying how forces are transmitted from one region of the cell to another. This comprehensive study of cell-cell, cell-matrix, and nuclear forces will greatly advance the understanding of epithelial homeostasis, which includes the processes of wound repair, inflammation, and epithelial tissue development and organization, as well as epithelial diseases, including cancer, fibrosis, and chronic inflammation. Junction and nuclear forces may represent a universal mechanism to regulate proliferation, migration, and organization; therefore, results from this study may also be relevant to a large number of non- epithelial cells and tissues.