Brain Pericyte and Amyloid-beta Peptide Interaction

描述（由申请方提供）：周细胞是位于内皮细胞层和脑实质之间的脑微血管外的小细胞。作为神经血管单位的一部分，周细胞除了有助于维持血脑屏障（BBB）和止血之外，还具有大量功能，包括收缩、免疫、吞噬和干细胞功能。阿尔茨海默病（AD）的一个病理学标志是受损的BBB，其特征在于内皮细胞外壁上的周细胞显著减少。内皮上的周细胞覆盖对于正常的BBB功能是必要的，并且这些细胞的破坏与AD症状的发展和进展之间的关系目前还没有很好地理解。了解周细胞功能在AD等病理条件下的重要性，将有助于开发未来的药物干预和改善治疗。本研究的目的是了解导致内皮细胞覆盖减少的机制和过程，以及在退行性疾病（如AD）中导致BBB减弱的机制和过程。 目的1是确定A是否降低PDGFR和参与周细胞介导的BBB完整性调节的信号分子，导致AD中BBB受损。如果PDGFRs控制周细胞向血管壁的募集，那么由A？诱导的PDGFR？表达减少将有助于解释AD中内皮壁外周细胞募集的损失或受损。 如果TGF？血管内皮生长因子和血管生成素-1/-2维持BBB紧密连接和细胞旁通透性，那么A？从周细胞分泌这些分子的减少将揭示导致AD中BBB受损和渗漏的另外未知机制。我们将使用RT-PCR、Western blot和定量成像技术来检测这些分子的表达和易位。目的2是确定A ²是否改变收缩和细胞骨架蛋白，从而降低周细胞的移动性、粘附性和迁移能力，导致周细胞向内皮的募集受损。周细胞向内皮细胞的运动在血管发育和维持中是关键的。考虑到细胞骨架和收缩蛋白在细胞形状、收缩、移动性和血脑屏障通透性调节中起关键作用，那么我们对这些蛋白质表达的研究，包括α-平滑肌肌动蛋白（<$-SMA）和肌球蛋白，以及在A <$存在下相关的肌动蛋白细胞骨架重组，将表明较少的周细胞被招募到内皮。使用体外毛细血管样结构，我们将阐明受A？影响的周细胞粘附和迁移中的限速步骤和关键信号分子。限速步骤将是治疗的理想目标。

DESCRIPTION (provided by applicant): Pericytes are small cells located outside of brain microvessels between the endothelial cell layer and the parenchyma. As part of the neurovascular unit, pericytes have a substantial range of functions including contractile, immune, phagocytic and stem cell functions, in addition to contributing to blood-brain barrier (BBB) maintenance and hemostasis. One pathological hallmark of Alzheimer's disease (AD) is a compromised BBB characterized by significant reductions in pericytes on the exterior walls of endothelia. Pericyte coverage on endothelia is necessary for normal BBB functioning and the relationship between destruction of these cells and the development and progression of AD symptoms is currently not well understood. Understanding the significance of pericyte functioning in pathological conditions such as AD will lead to the development of future pharmaceutical interventions and improved treatment. The objective of this study is to understand the mechanisms and processes that lead to reduced coverage of pericytes on the endothelial wall and the resulting weakening of the BBB in degenerative conditions such as AD. Aim 1 is to determine if A¿ decreases PDGFR¿ and signaling molecules involved in pericyte-mediated BBB integrity regulation, leading to a compromised BBB in AD. If PDGFR¿ controls the recruitment of pericytes to vessel wall, then reduced expression of PDGFR¿ induced by A¿ will help explain the loss or impaired recruitment of pericytes outside the endothelial wall in AD. If TGF¿, VEGF, and angiopoietin-1/-2 maintain BBB tight junction and paracellular permeability, then decreased secretion of these molecules from pericytes by A¿ will reveal an additional unknown mechanism leading to the compromise and leaks of the BBB in AD. We will examine the expression and translocation of these molecules using RT-PCR, Western blot and quantitative imaging techniques. Aim 2 is to determine if A¿ alters contractile and cytoskeletal proteins, therefore decreasing mobility, adhesion, and migration ability of pericytes, leading to impaired recruitment of pericytes to endothelia. Pericyte movement to endothelial cells is pivotal in vascular development and maintenance. Given that cytoskeletal and contratile proteins play key roles in cell shape, contraction, mobility and BBB permeability regulation, then our investigation of these proteins' expression, including alpha-smooth muscle actin (¿ -SMA) and myosin, and related actin cytoskeletal reorganization in the presence of A¿ will indicate that fewer pericytes are recruited to endothelia. Using in vitro capillary-like structures, we will idenify the rate-limiting step and key-signaling molecules in pericyte adhesion and migration affected by A¿. The rate-limiting step would be the ideal target for therapies.