Targeting Pathological Angiogenesis after Joint Injury

摘要 研究人员：特里斯坦·梅尔兹博士(PI)是一名生物医学工程师和早期研究员，专注于 关节损伤和创伤后骨关节炎(PTOA)。安德里亚·阿尔福德(Andrea Alford)博士(Co-Pi)是一位专注于矩阵生物学家 关于基质蛋白、细胞外基质和细胞之间的相互作用。加在一起，他们拥有广泛的 补充专业知识，使用创新方法研究凝血酶敏感蛋白-2在PTOA中的作用。 研究背景：PTOA约占骨关节炎病例的12%，约560万个症状-- 马季奇在美国的案例。滑膜炎现在越来越多地被认为是关节退行性变的永久性因素，类似于 它在风湿病中的作用。与炎症并存的是血管生成增加，这促进了- 炎症和组织分解代谢通过增加血管对炎症细胞和细胞因子的访问 联合。然而，还没有研究表明调节血管生成的程度是否会影响关节内血管生成。 关节损伤后大腿炎症和下游PTOA的严重程度。凝血酶敏感蛋白-2(TSP2)是一种内源性 抗血管生成因子，这项建议的初步数据表明，它在 关节损伤后的滑膜，使其成为关节内血管生成和PTOA的潜在调节器。 具体目标：1)。确定损伤时TSP2基因敲除增加的程度和 血管生成、滑膜炎和PTOA严重程度。2)。评估抗血管生成、抗炎和PTOA-MITI TSP2基因关节内转移的门控效应。 研究计划：在目标1中，单细胞RNAseq将用于分析TSP2(+)滑膜细胞群和 相关的血管生成途径。然后，一个全局的、可诱导的rosa26-CreerT2；TSP2flx小鼠将被用来 晚期TSP2评估关节内血管生成增加对滑膜炎、基质金属的影响程度。 蛋白水解酶活性(通过分子成像评估)，疼痛和功能，以及组织学和成像。 基于ING的PTOA严重程度。在目标2中，腺病毒TSP2将被关节内注射给WT和WT Rosa26-CreERT2；TSP2flx小鼠关节损伤后的变化及下游对关节内血管生成的影响 滑膜炎、基质金属蛋白酶活性、疼痛和功能、软骨细胞肥大和PTOA严重程度将被评估为 阐明TSP2是否可以作为一种疾病修正疗法。 创新：证明了创伤后血管生成程度与PTOA严重程度之间的关系 通过确定影响PTOA路径的潜在可修改的急性过程，ITE将是一个高影响力的发现- 起源。虽然TSP2的S抗血管生成作用在骨折愈合中已被广泛研究，但很少有文献报道。 TRUE已经阐明了它在滑膜和PTOA中的作用。最后，本提案旨在使用sev- 其他创新的成像方法来表征关节分解代谢和PTOA的严重程度，提供了一个潜在的- TIAL转换路径，用于早期、更敏感的PTOA和OA的诊断，使用创新的成像。

ABSTRACT INVESTIGATORS: Tristan Maerz, PhD (PI) is a biomedical engineer and early-stage investigator focused on joint injury and post-traumatic osteoarthritis (PTOA). Andrea Alford, PhD (Co-PI) is a matrix biologist focused on the interactions of matricellular proteins, the extracellular matrix, and cells. Together, they have extensive complementary expertise to study the role of thrombospondin-2 in PTOA using innovative methodologies. RESEARCH CONTEXT: PTOA accounts for ~12% of osteoarthritis cases, constituting ~5.6 million sympto- matic cases in the US. Synovitis is now increasingly recognized as a perpetuator of joint degeneration, analo- gous to its role in rheumatic diseases. Alongside inflammation is increased angiogenesis, which promotes in- flammation and tissue catabolism by increasing vascular access to inflammatory cells and cytokines within the joint. However, no study has demonstrated whether modulating the degree of angiogenesis affects intraarticu- lar inflammation and downstream PTOA severity after joint injury. Thrombospondin-2 (TSP2) is an endogenous anti-angiogenic factor, and this proposal’s preliminary data demonstrates that it is markedly upregulated in the synovium following joint injury, making it a potential regulator of intraarticular angiogenesis and PTOA. SPECIFIC AIMS: 1). Determine the extent to which temporal TSP2 knockout at the time of injury increases an- giogenesis, synovitis, and PTOA severity. 2). Assess the anti-angiogenic, anti-inflammatory, and PTOA-miti- gating effect of intraarticular TSP2 gene transfer. RESEARCH PLAN: In Aim 1, single-cell RNAseq will be used to profile TSP2(+) synovial cell populations and associated angiogenic pathways. A global, inducible Rosa26-CreERT2;TSP2flox mouse will then be used to ab- late TSP2 to assess the extent to which increased intraarticular angiogenesis affects synovitis, matrix metallo- proteinase (MMP) activity (assessed using molecular imaging), pain and function, and histological and imag- ing-based PTOA severity. In Aim 2, adenoviral TSP2 will be administered intraarticularly to both WT and Rosa26-CreERT2;TSP2flox mice after joint injury, and the downstream effect on intraarticular angiogenesis, synovitis, MMP activity, pain and function, chondrocyte hypertrophy, and PTOA severity will be assessed to elucidate whether TSP2 can be employed as a disease-modifying therapeutic. INNOVATION: Demonstrating a relationship between the degree of post-injury angiogenesis and PTOA sever- ity would be a high-impact finding by identifying a potentially-modifiable acute process that affects PTOA path- ogenesis. While TSP2’s anti-angiogenic role has been studied extensively in fracture healing, little to no litera- ture has elucidated its role in the synovium and in the context of PTOA. Lastly, this proposal aims to use sev- eral innovative imaging methodologies to characterize joint catabolism and PTOA severity, providing a poten- tial translational path for earlier, more sensitive PTOA and OA diagnosis using innovative imaging.