Jahagirdar Ravi, Attwell Sarah, Marusic Suzana, Bendele Alison, Shenoy Narmada, McLure Kevin G, Gilham Dean, Norek Karen, Hansen Henrik C, Yu Raymond, Tobin Jennifer, Wagner Gregory S, Young Peter R, Wong Norman C W, Kulikowski Ewelina
Resverlogix Corp., Calgary, Alberta, Canada (R.J., S.A., K.G.M., D.G., K.N., H.C.H., R.Y., J.T., G.S.W., P.R.Y., N.C.W.W., E.K.); Hooke Laboratories Inc., Lawrence, Massachusetts (S.M.); Bolder BioPATH Inc., Boulder, Colorado (A.B.); and Aravasc Inc., Sunnyvale, California (N.S.)
Resverlogix Corp., Calgary, Alberta, Canada (R.J., S.A., K.G.M., D.G., K.N., H.C.H., R.Y., J.T., G.S.W., P.R.Y., N.C.W.W., E.K.); Hooke Laboratories Inc., Lawrence, Massachusetts (S.M.); Bolder BioPATH Inc., Boulder, Colorado (A.B.); and Aravasc Inc., Sunnyvale, California (N.S.).
Mol Pharmacol. 2017 Dec;92(6):694-706. doi: 10.1124/mol.117.110379. Epub 2017 Sep 29.
Bromodomain (BD) and extra-terminal domain containing proteins (BET) are chromatin adapters that bind acetylated histone marks via two tandem BDs, BD1 and BD2, to regulate gene transcription. BET proteins are involved in transcriptional reprogramming in response to inflammatory stimuli. BET BD inhibitors (BETis) that are nonselective for BD1 or BD2 have recognized anti-inflammatory properties in vitro and counter pathology in models of inflammation or autoimmune disease. Although both BD1 and BD2 bind acetylated histone residues, they may independently regulate the expression of BET-sensitive genes. Here we characterized the ability of RVX-297, a novel orally active BETi with selectivity for BD2, to modulate inflammatory processes in vitro, in vivo, and ex vivo. RVX-297 suppressed inflammatory gene expression in multiple immune cell types in culture. Mechanistically, RVX-297 displaced BET proteins from the promoters of sensitive genes and disrupted recruitment of active RNA polymerase II, a property shared with pan-BETis that nonselectively bind BET BDs. In the lipopolysaccharide model of inflammation, RVX-297 reduced proinflammatory mediators assessed in splenic gene expression and serum proteins. RVX-297 also countered pathology in three rodent models of polyarthritis: rat and mouse collagen-induced arthritis, and mouse collagen antibody-induced arthritis. Further, RVX-297 prevented murine experimental autoimmune encephalomyelitis (a model of human multiple sclerosis) disease development when administered prophylactically and reduced hallmarks of pathology when administered therapeutically. We show for the first time that a BD2-selective BETi maintains anti-inflammatory properties and is effective in preclinical models of acute inflammation and autoimmunity.
含溴结构域（BD）和额外末端结构域的蛋白质（BET）是染色质衔接蛋白，通过两个串联的BD（BD1和BD2）结合乙酰化组蛋白标记，以调节基因转录。BET蛋白参与响应炎症刺激的转录重编程。对BD1或BD2无选择性的BET BD抑制剂（BETis）在体外具有公认的抗炎特性，并能对抗炎症或自身免疫性疾病模型中的病理变化。尽管BD1和BD2都结合乙酰化组蛋白残基，但它们可能独立调节BET敏感基因的表达。在此，我们表征了RVX-297（一种对BD2具有选择性的新型口服活性BETi）在体外、体内和离体条件下调节炎症过程的能力。RVX-297抑制了培养的多种免疫细胞类型中的炎症基因表达。从机制上讲，RVX-297将BET蛋白从敏感基因的启动子上置换下来，并破坏了活性RNA聚合酶II的募集，这是与非选择性结合BET BD的泛BETis共有的特性。在脂多糖炎症模型中，RVX-297降低了脾脏基因表达和血清蛋白中评估的促炎介质。RVX-297还对抗了三种多关节炎啮齿动物模型中的病理变化：大鼠和小鼠胶原诱导的关节炎以及小鼠胶原抗体诱导的关节炎。此外，RVX-297在预防性给药时可预防小鼠实验性自身免疫性脑脊髓炎（人类多发性硬化症模型）疾病的发展，并在治疗性给药时减轻病理特征。我们首次表明，BD2选择性BETi具有抗炎特性，并且在急性炎症和自身免疫的临床前模型中有效。
