The role BH3 and multi BH domain genes in regulating monocyte survival and functi

描述(申请人提供)：类风湿性关节炎(RA)是一种自身免疫性疾病，以滑膜衬里增生、炎症和软骨和骨骼破坏为特征。在RA中，抗凋亡和促凋亡的Bcl2家族成员之间的平衡可能向生存转移。我们发现，与对照组相比，RA滑膜组织中抗凋亡蛋白Bcl2和Mcl-1增加，而促凋亡蛋白Bim减少。由于胚胎死亡或出生后早期死亡，对Bcl-2家族抗凋亡成员缺陷的研究变得复杂起来。相反，缺乏促凋亡成员的小鼠，如Bak、Bax或Bim，则存活并成年。由于Bim通过隔离Bcl2/Mcl-1和/或激活Bak和Bax是关键的细胞凋亡激活剂，并且由于Bim在RA滑膜组织中减少，Bim是治疗RA的潜在靶点。我们证明，缺乏凋亡启动子Bim而不是下游效应子Bak或Bax的小鼠会发展成更严重的炎症性关节炎。在Bim-/-小鼠中，这种加重的疾病与细胞凋亡减少、促炎分子的表达增加以及血管内皮中更多的巨噬细胞有关。此外，Bim-/-巨噬细胞在内毒素刺激下表现出IL-6、IL-1β和TNFa水平升高，CD40和CD69表达增强。根据这些数据，我们假设Bim与Bcl2和/或Mcl-1的比率作为分子变阻器，决定了关节内巨噬细胞的增殖和激活程度。我们将使用药理学方法、整体动物方法和细胞特异性方法来确定BIM缺乏如何加剧炎症性关节炎。这些研究可能会导致类风湿关节炎的新的治疗方法。细胞死亡和生长的调节对于维持人体内的平衡至关重要。然而，在自身免疫性疾病-类风湿性关节炎(RA)的启动和/或发展过程中，这种平衡被打破。在RA中，细胞生长增加，细胞死亡减少，导致附着在软骨/骨交界处的组织异常增加，滑膜衬里。对RA患者关节组织的分析表明，巨噬细胞的数量与预后较差有关。单核细胞(巨噬细胞前体)和巨噬细胞是免疫细胞，在RA患者中产生有害因子，负责清除组织中的死亡细胞或碎片。我们证明，在RA患者的巨噬细胞中，由促死亡蛋白Bim介导的死亡信号级联是功能障碍的。此外，我们还表明，在所有细胞类型中都缺乏Bim的小鼠会患上更严重的关节炎，并且这些小鼠的巨噬细胞高度激活，这意味着它们会产生大量的有害因素，加剧炎症。因此，我们的目标是开发一种治疗方法，以激活Bim死亡途径，抑制或诱导RA的缓解。此外，我们的目标是描述缺乏Bim或it信号伙伴的小鼠，这些小鼠只在单核细胞和巨噬细胞中存在。

DESCRIPTION (provided by applicant): Rheumatoid arthritis (RA) is an autoimmune disease characterized by hyperplasia of the synovial lining, inflammation, and destruction of cartilage and bone. In RA, the balance between anti- and pro-apoptotic members of the Bcl-2 family may be shifted towards survival. We demonstrated that the anti-apoptotic proteins, Bcl-2 and Mcl-1 are increased while the pro-apoptotic protein Bim is decreased in RA synovial tissue as compared to controls. The study of deficiencies in anti-apoptotic members of the Bcl-2 family is complicated by embryonic lethality or early post-natal death. In contrast, mice deficient in pro-apoptotic Bcl-2 members such as Bak, Bax, or Bim survive and reach adulthood. Since Bim is a critical activator of apoptosis through sequestering Bcl-2/Mcl-1 and/or by activating Bak and Bax and since Bim is decreased in RA synovial tissue, Bim is a potential target for treatment of RA. We demonstrated that mice lacking the apoptotic initiator Bim but not the downstream effectors Bak or Bax develop a more severe form of inflammatory arthritis. This exacerbated disease in Bim-/- mice is associated with decreased apoptosis, increased expression of pro-inflammatory molecules, and more macrophages in pannus. Further, Bim-/- macrophages display elevated levels of IL-6, IL-1¿, and TNFa and enhanced expression of CD40 and CD69 in response to stimulation with LPS. Based on these data, we hypothesize that the ratio of Bim to Bcl-2 and/or Mcl- 1 serves as molecular rheostat that determines the extent of hyperplasia and activation of macrophages in the joint. We will use a pharmacological approach, a whole animal approach, and a cell-specific approach to identify how deficiency in Bim exacerbates inflammatory arthritis. These studies will potentially lead to novel therapeutic approaches to RA. The regulation of cell death and growth is vital for maintaining a balance in the human body. However, during the initiation and/or progression of the autoimmune disease, rheumatoid arthritis (RA), the balance is disrupted. In RA there is an increase in cellular growth and a concomitant decrease in cell death leading to an abnormal increase in the tissue that attaches to the cartilage/bone junction, the synovial lining. Analysis of tissue from joints of patients with RA revealed that the number of macrophages correlated with a worse prognosis. Monocytes (macrophage precursors) and macrophages are immune cells that produce the noxious factors in patients with RA and are responsible for removing dying cells or debris in tissues. We demonstrated that the death signaling cascade mediated by the pro-death protein Bim is dysfunctional in macrophages from patients with RA. Additionally, we have shown that mice lacking Bim in all cell types develop a worse form of arthritis and that the macrophages from these mice are highly activated, meaning they produce significant amounts of deleterious factors that exacerbate the inflammation. Therefore, our goal is to develop a therapeutic to activate the Bim death pathway and inhibit or induce remission in RA. Further our goal is to characterize mice lacking Bim or it signaling partners only in monocytes and macrophages.