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

描述（由申请人提供）：风湿性关节炎（RA）是一种自身免疫性疾病，其特征为滑膜衬里增生、炎症以及软骨和骨的破坏。在RA中，Bcl-2家族的抗凋亡和促凋亡成员之间的平衡可能会向生存转移。我们证明，RA滑膜组织中的抗凋亡蛋白Bcl-2和Mcl-1增加，而促凋亡蛋白Bim减少。研究Bcl-2家族抗凋亡成员的缺陷是复杂的胚胎致死或出生后早期死亡。相反，缺乏促凋亡Bcl-2成员如巴克、Bax或Bim的小鼠存活并达到成年。由于Bim是通过螯合Bcl-2/Mcl-1和/或通过激活巴克和Bax的凋亡的关键激活剂，并且由于Bim在RA滑膜组织中减少，因此Bim是治疗RA的潜在靶点。我们证明了缺乏凋亡启动子Bim而不是下游效应子巴克或Bax的小鼠会发展成更严重形式的炎性关节炎。Bim-/-小鼠中的这种恶化的疾病与细胞凋亡减少、促炎分子表达增加和血管翳中更多的巨噬细胞相关。此外，Bim-/-巨噬细胞响应于LPS刺激而显示IL-6、IL-1 β和TNF α水平升高以及CD 40和CD 69表达增强。基于这些数据，我们假设Bim与Bcl-2和/或Mcl- 1的比率充当分子变阻器，其决定关节中巨噬细胞增生和活化的程度。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。这些研究将可能导致新的治疗方法，类风湿关节炎。细胞死亡和生长的调节对于维持人体的平衡至关重要。然而，在自身免疫性疾病类风湿性关节炎（RA）的开始和/或进展期间，平衡被破坏。在RA中，存在细胞生长的增加和伴随的细胞死亡的减少，导致附着于软骨/骨连接部（滑膜衬里）的组织的异常增加。对RA患者关节组织的分析显示，巨噬细胞的数量与预后不良相关。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，并负责清除组织中的死亡细胞或碎片。我们证明了由促死亡蛋白Bim介导的死亡信号级联在RA患者的巨噬细胞中是功能失调的。此外，我们已经证明，在所有细胞类型中缺乏Bim的小鼠都会患上更严重的关节炎，并且这些小鼠的巨噬细胞高度活化，这意味着它们会产生大量加剧炎症的有害因素。因此，我们的目标是开发一种治疗剂来激活Bim死亡通路，抑制或诱导RA的缓解。此外，我们的目标是表征仅在单核细胞和巨噬细胞中缺乏Bim或其信号传导伴侣的小鼠。

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.