Efficacy of simultaneous blockade of myostatin and activin on the inhibition of joint destruction in experimental arthritis

同时阻断肌生长抑制素和激活素对抑制实验性关节炎关节破坏的功效

• 批准号: 515320408
• 负责人: Dr. Berno Dankbar, Ph.D.
• 金额: --
• 依托单位: Institut für Muskuloskelettale Medizin
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/515320408?language=en
• 关键词: Efficacy; simultaneous; blockade; myostatin; activin

Rheumatoid arthritis (RA) is the prototype of an inflammatory arthritis that is characterized by chronic inflammation, synovial hyperplasia, progressive cartilage destruction and bone erosion. In a recently published work, we described that chronic inflammation leads to an upregulation of myostatin in arthritic synovial tissues and that deficiency or pharmacological inhibition of myostatin highly ameliorates disease severity and in particular bone erosion and pannus formation in arthritic mice. Additionally, we could recently show that like myostatin, another member of the TGF-ß family namely activin A stimulates RANKL-induced osteoclast differentiation and inhibits osteoblast differentiation. Moreover, deficiency of activin A leads to decreased inflammation and bone destruction. Altogether, both myostatin and activin appear to be key players in arthritis development and associated joint destruction.Therefore, inhibiting myostatin and activin A simultaneously, thereby blocking not only osteoclast development, macrophage activation and fibroblast (FLS) proliferation but also promoting bone formation, may provide a powerful tool for the treatment of joint destruction in RA.In this context, a protein which is able to bind and antagonize myostatin as well as activin is the natural occuring antagonist follistatin (FST) and indeed a recombinant modified FST (FSTΔHBS-mFc) has been shown to have the capability to effectively block myostatin as well as activin signaling. Moreover, besides blocking myostatin and activin directly, inhibition could also be achieved by targeting the corresponding receptors thereby inhibiting receptor-ligand binding. In line with this, a dual-specific antibody against Acvr2a/ Acvr2b has been shown to facilitate a complete blockade of the myostatin- or activin A signaling response.Taking the inhibitory properties of FSTΔHBS-mFc and anti-Acvr2a/2b antibody into account, we want to test the efficacy of these factors to ameliorate inflammatory joint destruction in various mouse models of RA. In the present project, we proposed to study and compare the effects of FSTΔHBS and the dual-specific anti-Acvr2a/b antibody on cartilage and bone erosion, pannus formation, cytokine and chemokine production and immune cell infiltration in a chronic (hTNFtg) as well as an acute (K/BxN serum transfer) arthritis model.Moreover, investigating the impact of both inhibitors as well as FLS-expressed FST on osteoclast and osteoblast differentiation and on FLS aggressive behavior itself is focus of our in vitro studies. In this regard, conditioned media experiments with arthritic FLS, osteoblasts and BMMs will provide insights into the impact of paracrine myostatin/ activin on osteoclast and osteoblast development. Functional assays on FLS adhesion, proliferation, migration and invasion should provide detailed information about the effectiveness of simultaneous inhibition on pannus formation and cartilage degradation by activated FLS.

类风湿性关节炎（RA）是一种以慢性炎症、滑膜增生、进行性软骨破坏和骨质侵蚀为特征的炎性关节炎的原型。在最近发表的工作中，我们描述了慢性炎症导致关节炎滑膜组织中肌生长抑制素的上调，并且肌生长抑制素的缺乏或药理学抑制高度改善了关节炎小鼠中疾病的严重程度，特别是骨侵蚀和血管翳形成。此外，我们最近发现，像肌生长抑制素一样，TGF-β家族的另一个成员，即激活素A刺激RANKL诱导的破骨细胞分化并抑制成骨细胞分化。此外，激活素A的缺乏导致炎症和骨破坏减少。总之，肌肉生长抑制素和激活素似乎是关节炎发展和相关关节破坏的关键参与者。因此，同时抑制肌肉生长抑制素和激活素A，从而不仅阻断破骨细胞发育、巨噬细胞活化和成纤维细胞（FLS）增殖，而且促进骨形成，可能为治疗RA中的关节破坏提供有力的工具。在这种情况下，一种能够结合并拮抗肌生长抑制素和激活素的蛋白质是天然存在的拮抗剂卵泡抑素（FST），并且事实上，重组修饰的FST（FSTΔHBS-mFc）已被证明具有有效阻断肌生长抑制素和激活素信号传导的能力。此外，除了直接阻断肌生长抑制素和激活素之外，还可以通过靶向相应的受体从而抑制受体-配体结合来实现抑制。与此相一致的是，针对Acvr 2a/Acvr 2b的双特异性抗体已被证明有助于完全阻断肌肉生长抑制素或激活素A信号传导反应。考虑到FSTΔHBS-mFc和抗Acvr 2a/2b抗体的抑制特性，我们希望测试这些因子在各种RA小鼠模型中改善炎症关节破坏的功效。在本项目中，我们提议研究和比较FSTΔHBS和双特异性抗Acvr 2a/B抗体对慢性（hTNFtg）和急性中软骨和骨侵蚀、血管翳形成、细胞因子和趋化因子产生以及免疫细胞浸润的影响（K/BxN血清转移）关节炎模型。此外，研究这两种抑制剂以及FLS表达的FST对破骨细胞和成骨细胞分化以及对FLS侵袭行为本身的影响是我们体外研究的重点。在这方面，条件培养基实验与关节炎FLS，成骨细胞和成骨细胞将提供见解的影响，旁分泌肌生长抑制素/激活素对破骨细胞和成骨细胞的发展。关于FLS粘附、增殖、迁移和侵袭的功能测定应提供关于通过活化的FLS同时抑制血管翳形成和软骨降解的有效性的详细信息。