Annexins and Osteoarthritis

项目摘要 Annexins成为治疗包括癌症在内的各种疾病的有吸引力的治疗靶点， 心血管疾病和糖尿病，因为它们有能力调节活动的重要信号 参与疾病病理的通路。膜联蛋白(ANX)A5和AnxA6在骨关节炎中的高表达 (骨性关节炎)软骨；然而，关于它们在骨性关节炎病理中的作用，我们一无所知。两条主要的信号通路与 在骨性关节炎中的角色是核因子-B和WNT/？-连环蛋白(WNT)，鼓励我们研究潜在的相互作用 在AnxA5和AnxA6之间以及这些信号通路之间。正被激活的核因子-B信号通路 在关节软骨细胞中，包括白介素1在内的各种细胞因子是主要的分解代谢因子之一 OA中的信号通路，而Wnt信号通路最近被证明具有抗分解代谢的作用 在人类关节软骨细胞中发挥作用，而在小鼠软骨细胞中起分解代谢作用。我们的初步调查结果 结果表明，AnxA5和AnxA6在刺激核因子-B信号的同时抑制Wnt信号。此外，我们的发现 提示AnxA5通过与钙调蛋白直接相互作用来调节核因子-B和Wnt信号。 半胱氨酸蛋白酶的钙蛋白酶，从而刺激钙蛋白酶的活性。Calain刺激核因子-B信号，而 抑制Wnt信号。另一方面，AnxA6通过直接与p65单位结合来刺激核因子-B信号 而它通过干扰Wnt的膜结合来抑制Wnt信号转导 信号复合体，这是激活Wnt信号所必需的。基于这些发现，我们假设 AnxA5和AnxA6通过不同的机制调节核因子-B和Wnt信号来刺激 骨性关节炎病理过程中软骨破坏。为了验证我们的假设，我们提出了两个目标。在第一个 目的我们将确定AnxA5/calastatin和AnxA6/p65相互作用的性质，以及这些相互作用是如何 相互作用会影响核因子-B信号的活性。此外，我们将确定AnxA5/Calastatin之间的相互作用 AnxA6对Wnt信号的影响及钙依赖的质膜结合如何干扰 Wnt信号复合体的膜结合，最终Wnt信号活性。此外，我们还将 确定AnxA5和AnxA6如何单独和共同影响衰老过程中的核因子-B和Wnt信号，IL-1 在AnxA5和AnxA6单基因敲除和双基因敲除小鼠的膝关节内注射或手术诱导的骨关节炎。在……里面 目的2，我们将确定膜联蛋白介导的这些信号通路对功能的影响 和人关节软骨细胞的表型。最后，我们将确定膜联蛋白介导的抑制 WNT信号转导对AnxA5和AnxA6单、双基因敲除关节软骨细胞OPG表达的影响 AnxA5和AnxA6过表达软骨细胞，最终形成破骨细胞和软骨下骨 骨性关节炎的病理改变。我们期待这项提议的成功完成将提供新的 骨性关节炎病理过程中刺激软骨破坏的机制及治疗新靶点 治疗骨性关节炎！

Project Summary Annexins became attractive therapeutic targets for the treatment of various diseases, including cancer, cardiovascular diseases and diabetes, because of their ability to modulate the activities of important signaling pathways involved in disease pathology. Annexin (Anx)A5 and AnxA6 are highly expressed in osteoarthritic (OA) cartilage; however, nothing is known about their role in OA pathology. Two major signaling pathways with roles in OA are NF-¿B and the Wnt/¿-catenin (Wnt), encouraging us to examine the potential interaction between AnxA5 and AnxA6 and these signaling pathways. NF-¿B signaling pathway, which is being activated in articular chondrocytes by various cytokines, including interleukin (IL)-1, is one of the major catabolic signaling pathway in OA, whereas the Wnt signaling pathway has been recently shown to act anti-catabolically in human articular chondrocytes while acting catabolically in mouse chondrocytes. Our preliminary findings show that AnxA5 and AnxA6 stimulate NF-¿B signaling while inhibiting Wnt signaling. In addition, our findings suggest that AnxA5 modulates NF-¿B and Wnt signaling via direct interaction with calpastatin, an inhibitor of the cysteine protease calpain, thereby stimulating calpain activity. Calpain stimulates NF-¿B signaling, while inhibiting Wnt signaling. AnxA6, on the other hand, stimulates NF-¿B signaling via direct binding to the p65 unit of the NF-¿B complex, while it inhibits Wnt signaling via interfering with membrane association of the Wnt signaling complex, which is required for Wnt signaling activation. Based on these findings, we hypothesize that AnxA5 and AnxA6 act via different mechanisms, to modulate NF-¿B and Wnt signaling to stimulate cartilage destruction during OA pathology. To test our hypothesis, we are proposing two aims. In the first aim we will determine the nature of the AnxA5/calpastatin and AnxA6/p65 interactions, and how these interactions affect NF-¿B signaling activity. In addition, we will determine how the AnxA5/calpastatin interaction affect Wnt signaling and how Ca2+-dependent plasma membrane association of AnxA6 interferes with the membrane association of the Wnt signaling complex and ultimately Wnt signaling activity. Furthermore, we will determine how AnxA5 and AnxA6 individually and together affect NF-¿B and Wnt signaling during aging, IL-1 injection in the knee joint or surgically induced OA in AnxA5 and AnxA6 single and double knockout mice. In Aim 2, we will determine the effect of annexin-mediated modulation of these signaling pathways on the function and phenotype of human articular chondrocytes. Finally, we will determine how annexin-mediated inhibition of Wnt signaling affects OPG expression in AnxA5 and AnxA6 single and double knockout articular chondrocytes and AnxA5 and AnxA6 overexpressing chondrocytes and ultimately osteoclastogenesis and subchondral bone changes in OA pathology. We expect that the successful completion of this proposal will provide novel mechanisms stimulating cartilage destruction during OA pathology and novel therapeutic targets for the treatment of OA.!