Novel allosteric ligands of the angiotensin receptor AT1R as autoantibody blockers
Novel allosteric ligands of the angiotensin receptor AT1R as autoantibody blockers
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DOI：
10.1073/pnas.2019126118
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发表时间：
2021-08-17
影响因子：
11.1
通讯作者：
Karnik, Sadashiva S.
中科院分区：
文献类型：
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作者：
Singh, Khuraijam Dhanachandra;Jara, Zaira P.;Karnik, Sadashiva S.
虽然血管紧张素II (AngII) 1型受体（AT1R）的正构配体可用于临床和研究应用，但这种重要的G蛋白偶联受体（GPCR）的变构配体尚不为人所知。变构配体是调节受体药理学和亚型选择性的有用工具。在这里，我们报道了AT1R变构配体在阻断自身免疫抗体方面的潜在应用。AT1R自身抗体的表位位于细胞外环2的正位袋外。AT1R结构的分子动力学模拟研究揭示了包含自身抗体表位的可药物变构口袋的存在。然后使用基于结构的高通量虚拟筛选为该口袋确定小分子粘合剂。获得的前18个hit抑制了抗体与AT1R的结合，并调节了激动剂诱导的AT1R钙反应。在详细研究的18种化合物中，有两种化合物对天然激动剂AngII的功能具有负变构调节作用。它们阻断了抗体增强的钙反应和血管平滑肌细胞中活性氧的产生，以及血管i诱导的血管收缩，证明了它们在体内的有效性。因此，我们的研究证明了发现gpcr致病自身抗体抑制剂的可行性。具体来说，对于AT1R，我们期望开发更有效的变构候选药物来干预自身免疫性疾病，如先兆子痫、双侧肾上腺增生和器官移植排斥反应。
While orthosteric ligands of the angiotensin II (AngII) type 1 receptor (AT1R) are available for clinical and research applications, allosteric ligands are not known for this important G protein-coupled receptor (GPCR). Allosteric ligands are useful tools to modulate receptor phar-macology and subtype selectivity. Here, we report AT1R allosteric ligands for a potential application to block autoimmune antibodies. The epitope of autoantibodies for AT1R is outside the orthosteric pocket in the extracellular loop 2. A molecular dynamics simulation study of AT1R structure reveals the presence of a druggable allosteric pocket encompassing the autoantibody epitope. Small molecule bind-ers were then identified for this pocket using structure-based high-throughput virtual screening. The top 18 hits obtained inhibited the binding of antibody to AT1R and modulated agonist-induced calcium response of AT1R. Two compounds out of 18 studied in detail exerted a negative allosteric modulator effect on the functions of the natural agonist AngII. They blocked antibody-enhanced calcium response and reactive oxygen species production in vascular smooth muscle cells as well as AngII-induced constriction of blood vessels, demonstrating their efficacy in vivo. Our study thus demonstrates the feasibility of discovering inhibitors of the disease-causing autoantibodies for GPCRs. Specifically, for AT1R, we anticipate development of more potent allosteric drug candidates for intervention in autoimmune mal-adies such as preeclampsia, bilateral adrenal hyperplasia, and the re-jection of organ transplants.