Research of rheumatoid arthritis using Dbl knock-out mice

类风湿关节炎(RA)是一种慢性多发性关节炎，最终导致关节破坏。虽然家族性类风湿性关节炎患者的兄弟姐妹患病的风险比家族性类风湿性关节炎高得多，提示遗传因素可能是家族聚集性的重要原因，但我们先前在日本家族性类风湿性关节炎中报道了3个主要的染色体连锁区域，即D1S253/214、D8S556和DXS1232。Komai等人。DXS1232/984上的DBL原癌基因(野生型DBL；GenBank/EMBL/DDBJ登录号：AB085902)是一个缺失外显子23和24的突变型DBL基因(缺失型DBL；GenBank/EMBL/DDBJ登录号：AB085902)。(AB085901)与家族性RA相关。DBL原癌基因是一种典型的鸟嘌呤核苷酸交换因子，调节小G蛋白的活性，包括Rho家族GTP酶、RhoA和CDC42以及可能的rac1。Db1将客户蛋白质从Gdp结合(非活性)形式转换为Gtp结合(动作…更多)形成，允许其效应域与下游信号分子相互作用。以前的研究表明，Rho家族的GTP酶控制着肌动蛋白细胞骨架的组织，并调节细胞的运动、增殖和凋亡。在人类中，Rho家族的GEF在骨骼肌或神经的成熟和组织以及淋巴样细胞的成熟和细胞因子的产生中发挥着重要的作用。一些全球环境基金家族基因的突变已被认为与人类疾病有关，如面部生殖器发育不良。已有研究表明，缺失形式的DBL对Cd_(C42)显示出较弱的全球环境基金活性，并且在类风湿患者中性粒细胞的渗透和NADPH氧化酶活性显著降低。本研究从DBL基因敲除小鼠建立了小鼠胚胎成纤维细胞(MEF)细胞系，并评价了Rho家族蛋白的活性以及DBL蛋白在突变型和野生型MEF中的定位和迁移。结果表明，DBL原癌基因通过降低细胞内迁移率而影响MEF中Rho家族蛋白的激活。我们现在将DBL基因敲除的小鼠与DBIJ小鼠进行回交，以检测DBL基因缺失对小鼠胶原性关节炎的影响。较少

Rheumatoid arthritis (RA) is a chronic polyarthritis finally leading to joint destruction. While the ratio of the risk for siblings of patients with a disease was much greater in familial RA, suggesting that genetic factors may be important as a cause of familial clustering, we have previously reported in Japanese familial RA with 3 principal chromosomal regions of linkage, D1S253/214, D8S556 and DXS1232. Komai et al. have subsequently identified DBL proto-oncogene (wild type DBL; GenBank/EMBL/DDBJ Accession No.AB085902) located on DXS1232/984 as a candidate for RA disease gene : a mutant DBL cDNA lacking exons 23 and 24 (deleted type DBL ; GenBank/EMBL/DDBJ Accession No. AB085901) was associated with familial RA.The DBL proto-oncogene is a prototype guanine nucleotide exchange factor (GEF) that modulates activity of small G proteins, including Rho family GTPases, RhoA and Cdc42 and possibly Rac1. Dbl converts the client proteins from the GDP-bound (inactive) form to the GTP-bound (act … More ive) form, allowing its effector domain to interact with downstream signaling molecules. Previous studies have shown that the Rho family GTPases control actin cytoskeleton organization and modulate movement, proliferation, and apoptosis of the cell. In humans, Rho family GEFs play important roles in the maturation and organization of skeletal muscles or nerves, also in the maturation and cytokine production of lymphoid cells. The mutation in some of the GEF family genes has been implicated in the human disease such as faciogenital dysplasia ^<15)>. It have been reported that deleted form of Dbl showed a weaker GEF activity toward Cdc42, and that infiltration and NADPH oxidase activity of neutrophils were significantly decreased in rheumatoid patients with this deleted mutant DBL.In the present study, we established mouse embryonic fibroblast(MEF) cell lines from Dbl knock-out mice and evaluated the activity of Rho family proteins and the intracellular localization and mobility of Dbl protein in mutant or wild type MEFs. The result showed that Dbl proto-oncogene affect the activation of Rho family proteins in MEFs through the decrease of intracellular mobility. We are now going to back-cross Dbl knock-out mice with DBIJ mice to examine the effects of Dbl gene-deletion on collagen-induced arthritis in mice. Less