Deconstructing Cartilage Mechanotransduction by Piezo Channels

通过压电通道解构软骨机械传导

• 批准号: 10533155
• 负责人: Farshid Guilak
• 金额: $ 1.86万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10533155
• 关键词: Actins; Affect; Agonist; Biomechanics; Calcium; Calcium Channel; Cartilage; Cell Nucleus; Cells; Chemicals; Chondrocytes; Chromatin; Complex; Cytoskeleton; DNA Damage; Degenerative polyarthritis; Disease; Etiology; F-Actin; Gene Expression; Genetic Transcription; Goals; Health; Heterochromatin; Inflammation; Inflammatory; Interleukin-1 alpha; Interleukins; Ion Channel Gating; Joints; Kinetics; Lead; Mechanics; Mediating; Nuclear; Nuclear Lamina; Pain; Periodicity; Persons; Physiology; Piezo 1 ion channel; Piezo ion channels; Play; Polymers; Role; Signal Pathway; Signal Transduction; Structure; Tissues; Transcriptional Regulation; Up-Regulation; articular cartilage; chromatin remodeling; cytokine; depolymerization; insight; mechanical load; mechanical properties; mechanotransduction; novel therapeutics; response

Osteoarthritis (OA) is the most common degenerative joint disease, affecting more than 350 million people worldwide. Along with inflammation and pain, a hallmark of OA is the degradation of articular cartilage (AC), an avascular tissue that coats and facilitates the bending of diarthrodial joints. AC withstands millions of cyclic mechanical loads annually, and chondrocytes, the only cellular substrate in the tissue, sense these loads through mechanically gated ion channels. Piezo1 is a highly expressed calcium ion channel in chondrocytes that can be activated through mechanical loading or chemically with Yoda1, a Piezo1-specific agonist. Our lab recently demonstrated that Piezo1 expression is elevated in osteoarthritic cartilage and interleukin-1α (IL-1α), a pro-inflammatory cytokine present in OA, drives the upregulation Piezo1. The increased expression of Piezo1 in IL-1α-challenged chondrocytes led to a sustained increased intracellular calcium transient and the rarefication of the actin cytoskeleton. Herein, our overall goal is to understand how Piezo1-mediated changes in chondrocyte physiology contribute to the progression of OA during periods of high inflammation and injurious loading. Mechanical loading and subsequent calcium influx through calcium ion channels leads Calcium- mediated Actin Reset (CaAR) and nuclear softening via chromatin remodeling. CaAR is a transient cell response in which F-actin rapidly depolymerizes from the periphery of the cell and polymerizes around the nucleus to create a protective kinetic barrier that shields the nucleus from mechanical deformation. Nuclear softening driven by a decrease in heterochromatin was shown to be Piezo1 dependent and play a role in minimizing DNA damage during periods of high mechanical strain. While CaAR and nuclear softening have been characterized independently as mechanoprotective responses, their potential interplay in mediating nuclear mechanoprotection and regulation of transcription during mechanical loading has yet to be explored. The Linker of Nucleoskeleton and Cytoskeleton (LINC) complex physically tethers the nuclear lamina and the actin cytoskeleton, and it is known play a role in chromatin remodeling. Given the structure and function of the LINC complex, it is a strong candidate for mediating chromatin fluidification during nuclear softening and transcriptional responses during CaAR. Together these findings suggest that Piezo1-mediated CaAR could alter nuclear mechanical properties through chromatin remodeling via the LINC complex and lead to transcriptional changes that could ultimately affect chondrocyte cell fate during OA. Therefore, we hypothesize that elevated Piezo1 expression, as seen in OA cartilage, leads to a prolonged CaAR response which in turn triggers chromatin fluidification via the LINC complex thereby leading to an increase nuclear softening and pro- inflammatory gene expression in IL-1α-challenged chondrocytes.

骨关节炎（OA）是最常见的退行性关节疾病，影响超过3.5亿人 全世界。与炎症和疼痛一起，OA的标志是关节软骨（AC）的降解， 甲壳和促进腹膜关节弯曲的血管组织。 AC承受数百万循环 机械载荷每年和软骨细胞，是组织中唯一的细胞底物，感觉这些负载 通过机械门控离子通道。压电1是软骨细胞中高度表达的钙离子通道 可以通过机械载荷激活或用Yoda1（一种压电1特异性激动剂）化学激活。我们的实验室 最近证明，在骨关节炎软骨和白介素1α（IL-1α）中，压电1表达升高 OA中存在的促炎性细胞因子驱动上调压电。压电1的表达增加 在IL-1α挑战的软骨细胞中，导致持续增加的细胞内钙瞬态和 肌动蛋白细胞骨架的稀疏。在此，我们的总体目标是了解Piezo1介导的变化如何 在软骨细胞生理中，在高注射和损伤期间有助于OA的进展 加载中。机械负荷和随后通过钙离子通道的钙影响导致钙 - 通过染色质重塑，介导的肌动蛋白复位（CAAR）和核软化。 CAAR是瞬态细胞 F-肌动蛋白从细胞的周围迅速解散并在周围聚合。 核形成一个受保护的动力学屏障，该动力屏障屏蔽了核免受机械变形的影响。核 通过杂染色质减少，软化驱动驱动驱动依赖于压电1，并在 在高机械应变期间最小化DNA损伤。而CAAR和核软化具有 被视为机械保护反应独立表征，它们在中介中的潜在相互作用 机械加载过程中的核机制保护和调节机械载荷过程尚未探索。 核骨骼和细胞骨架（LINC）络合物的接头物理构造了核薄片和 肌动蛋白细胞骨架，众所周知，它在染色质重塑中起着作用。给定该结构和功能 Linc Complex，它是在核软化过程中介导染色质流体的有力候选者 CAAR期间的转录响应。这些发现一起表明Piezo1介导的CAAR可以 通过染色质重塑，通过linc络合物来改变核机械性能，并导致 转录变化最终可能影响OA期间软骨细胞的命运。因此，我们假设 如在OA软骨中所见，这种升高的压电表达导致了长时间的CAAR响应 触发染色质流化通过林络合物，从而导致核软化和促进 IL-1α挑战的软骨细胞中的炎症基因表达。