基于SIRT3-MnSOD-线粒体ROS信号通路探讨白藜芦醇抑制FLS增殖的作用机制

Rheumatoid arthritis (RA) is an autoimmune disease involving hyper-proliferation of the synovial membrane and fibroblast-like synoviocytes (FLS), leading to progressive joint destruction. Reactive oxygen species (ROS) as inflammatory mediators derived from activated macrophage. A high level of ROS can lead to direct damage to hyaluronic acid, lipids, cartilage matrix and DNA. The superoxide dismutase(SOD) are antioxidant enzymes that catalyze the dismutation of superoxide into hydrogen peroxide and oxygen. Manganese superoxide dismutase (MnSOD or Sod2) is one of the SOD isoforms and is located in the matrix of mitochondria. MnSOD is a nuclear-encoded mitochondrial enzyme that scavenges superoxide radicals and is thought to be an important determinant of sensitivity to ROS-induced cytotoxicity. Despite the ROS is associated with RA, the relationship between MnSOD and FLS remains obscure. Sirtuins are protein deacetylases and hydrolyze one NAD+ for each lysine residue. Sirtuins are involved in regulation of metabolism and stress responses. Mammalia have seven Sirtuins isoforms, SIRT1 to SIRT7. SIRT3 is located to mitochondria. The natural polyphenolic compound resveratrol is well known for its antioxidant properties. Resveratrol can affect Sirtuins activation (including SIRT1 and SIRT3). Adjuvant arthritis (AA) is the most widely used experimental models for studying the pathogenesis of RA and for screening the new drugs to treat rheumatoid disease, which shares some features with human RA, such as swelling, cartilage degradation, and loss of joint function. In this study, we established an AA model by injection of Freund's complete adjuvant (FCA) to investigate the effects of resveratrol. Synoviocytes isolated from knee joint of rats were treated with different doses of hydrogen peroxide in vitro. The new study found that moderate oxygen pressure could promote FLS proliferation, mitochondrial ROS target antagonists and resveratrol inhibited FLS proliferation which induced by H2O2; At the same time, resveratrol could cause FLS mitochondrial MnSOD high expression, reduce the mitochondrial ROS levels. The results suggested that: 1) mitochondrial ROS might play an important role in FLS abnormal proliferation; 2) resveratrol might lower the mitochondrial ROS concentration by inhibiting FLS abnormal proliferation. This project intends to carry out the following research: 1) comprehensive confirmed mitochondrial ROS on FLS abnormal proliferation; 2) in vitro and in vivo tests proved resveratrol could inhibit FLS abnormal proliferation and possible molecular mechanism. Expected results will help further understanding the pathogenesis of RA and provide new targets for drug design.

成纤维样滑膜细胞（FLS）异常增殖是类风湿性关节炎（RA）的基础，活性氧（ROS）在肿瘤细胞增殖中起重要作用。我们最新研究发现适度过氧化氢促进FLS增殖，线粒体靶向ROS拮抗剂和白藜芦醇抑制过氧化氢诱导的FLS增殖，锰超氧化物歧化酶（MnSOD）高表达可降低FLS线粒体ROS水平。鉴于白藜芦醇的抗氧化作用是活化去乙酰化酶家族的线粒体SIRT3，SIRT3引起MnSOD赖氨酸去乙酰化而减少线粒体ROS生成。本课题假设：1）线粒体ROS在FLS异常增殖中起重要作用；2）白藜芦醇抑制FLS异常增殖是通过调节MnSOD活性而降低线粒体ROS。我们将围绕线粒体ROS，运用细胞生物学和分子生物学等技术进行以下研究：1）证实线粒体ROS在氧压诱导FLS异常增殖中的作用；2）探明SIRT3-MnSOD-线粒体ROS信号通路在白藜芦醇抑制FLS增殖中的作用机制。预期结果为RA的机理阐明和药物设计提供新靶点。

成纤维样滑膜细胞（FLS）异常增殖是类风湿性关节炎（RA）的基础，活性氧（ROS）在肿瘤细胞增殖中起重要作用。我们前期研究发现适度过氧化氢促进FLS增殖，线粒体靶向ROS拮抗剂和白藜芦醇抑制过氧化氢诱导的FLS增殖，锰超氧化物歧化酶（MnSOD）高表达可降低FLS线粒体ROS水平。鉴于白藜芦醇的抗氧化作用是活化去乙酰化酶家族的线粒体SIRT3，SIRT3引起MnSOD赖氨酸去乙酰化而减少线粒体ROS生成。本课题主要研究：1）线粒体ROS在FLS异常增殖中起重要作用；2）白藜芦醇抑制FLS异常增殖是通过调节MnSOD活性而降低线粒体ROS。我们将围绕线粒体ROS，运用细胞生物学和分子生物学等技术进行以下研究：1）证实线粒体ROS在氧压诱导FLS异常增殖中的作用；2）探明SIRT3-MnSOD-线粒体ROS信号通路在白藜芦醇抑制FLS增殖中的作用机制。研究结果表明，白藜芦醇抑制类风湿性关节炎成纤维样滑膜细胞异常增殖是通过调节SIRT3-MnSOD蛋白表达进而调节线粒体ROS含量，促进HFLSs凋亡，达到抑制HFLSs增殖的目的。本研究探明线粒体ROS在引起FLS异常增殖中的作用，将有助于我们进一步认识RA的发病机理，为RA的发病机理阐明和药物设计提供新靶点；同时，采用白藜芦醇进行干预和治疗，为白藜芦醇在临床上治疗RA提供了实验基础和理论依据。