Perivascular macrophages endothelial interactions at the blood labyrinth barrier

描述（由申请人提供）：耳蜗血管纹中的血迷宫屏障（BLB）维持耳蜗内电位、离子转运和内耳液体平衡。长期以来，BLB的破坏一直被认为是各种听力障碍的主要病因，包括自身免疫性内耳疾病、梅尼埃病、脑膜炎相关迷路炎和一些遗传相关疾病。然而，尽管血凝块的重要性，控制血凝块渗透性的机制仍然很大程度上是未知的。我们实验室最近的一项研究意外地发现，除了内皮细胞（ECs）、基底膜和周围周细胞外，BLB中还存在大量血管周围巨噬细胞（pvm）。pvm通过含有大量囊泡和转运体的细胞塑性过程（端足）与血管密切接触。我们假设pvm和ECs在生理上是耦合的，以控制血管纹中的水和离子运动。在这个项目中，我们询问pvm是否有助于BLB的完整性。如果是这样，pvm是否通过影响紧密和粘附连接蛋白的表达来控制BLB的完整性？这种控制是否由色素上皮衍生因子介导？为了验证这一假设，我们建立了一种新的原代EC和PVM细胞共培养模型，并将其与转基因小鼠模型结合使用。转基因小鼠编码白喉毒素受体，提供了一种瞬时消耗pvm的系统。在解决PVM控制BLB完整性的问题上，所提出的工作将显著提高我们在细胞和分子水平上对BLB的理解，并可能最终导致BLB功能障碍相关听力损失的创新治疗。

DESCRIPTION (provided by applicant): The blood-labyrinth barrier (BLB) in the stria vascularis of the cochlea maintains endocochlear potential, ion transport, and fluid balance in the inner ear. Disruption of the BLB has long been considered a major etiologic factor in a variety of hearing disorders, including autoimmune inner ear disease, Meniere's disease, meningitis-associated labyrinthitis, and several genetically-linked diseases. Despite the importance of the BLB, however, the mechanisms that control BLB permeability remain largely unknown. A recent study from our lab unexpectedly found a large number of perivascular resident macrophage (PVMs) in the BLB, in addition to endothelial cells (ECs), basement membrane, and surrounding pericytes. The PVMs are in close contact with vessels through cytoplastic processes-end-feet-which contain a large number of vesicles and transporters. We hypothesize the PVMs and ECs are physiologically coupled for control of water and ion movement in the stria vascularis. In this project, we ask if PVMs contribute to the integrity of th BLB. If so, do PVMs control BLB integrity by affecting expression of tight and adherens junction proteins? Is the control mediated by pigment epithelial-derived factor? To test the hypothesis, we established a new primary EC and PVM cell co-culture model which we will use in association with a transgenic mouse model. The transgenic mice encode a diphtheria toxin receptor providing a system for transient depletion of PVMs. In addressing PVM control of BLB integrity, the proposed work will significantly enhance our understanding of the BLB at the cellular and molecular level and may ultimately lead to innovative treatments for BLB dysfunction-related hearing loss.