Alkoxypsoralens, Small Molecule Blockers of the Voltage-Gated Kv1.3 Channel

描述（由申请人提供）：特异性K+通道调制为新药的开发提供了巨大的潜力。构成一个特别有希望的治疗靶点的通道是电压门控Kv1.3通道。同源的Kv1.3通道在T淋巴细胞和B淋巴细胞中被发现，它们在终末分化效应记忆T （TEw）细胞和类别转换记忆B细胞中的表达上调，这表明Kv1.3阻滞剂可用于治疗多发性硬化症、1型糖尿病、牛皮癣、接触性皮炎、类风湿关节炎和重症肌无力等自身免疫性疾病。这一概念已经被证实，来自多发性硬化症和1型糖尿病患者的自身反应性T细胞主要是Kv1.3-高TEM细胞，Kv1.3阻断肽ShK可以治疗多发性硬化症的动物模型。然而，尽管Kv1.3具有明显的治疗重要性，但制药行业迄今尚未成功开发出选择性和有效的小分子Kv1.3阻滞剂。利用烷氧补骨脂素PAP-1，我的实验室最近发现了Kv1.3的第一个小分子抑制剂，它以2 nM的EC50阻断该通道，并对心脏钾通道Kv1.5表现出选择性。PAP-1不表现出细胞毒性或光毒性作用，在Ames试验中呈阴性，当腹腔或口服给药时，可有效抑制人TEM细胞的增殖并抑制延迟型超敏反应（DTH），这是TEM细胞介导的反应。因此，PAP-1似乎是进一步探索Kv1.3作为免疫抑制靶点的一个很好的新工具，并有可能发展成为口服免疫调节剂。在这一建议的帮助下，我们打算彻底探索PAP-1的治疗潜力。在Aim-1下，我们将测定PAP-1的药代动力学，并测试PAP-1长期抑制记忆细胞对免疫系统的影响。在Aim 2中，我们将测试PAP-1是否治疗过敏性接触性皮炎（CD8+ T细胞介导的皮肤反应如牛皮癣的动物模型）和实验性自身免疫性重症肌无力（T细胞依赖性抗体介导的自身免疫性疾病重症肌无力的模型）。由于TEM细胞在早期和晚期移植排斥反应中也发挥重要作用，我们将在大鼠肾移植模型中进一步测试PAP-1是否可以抑制急性和慢性排斥反应（Aim 3）。钾离子通道是指在细胞膜上穿隧并传导钾离子的蛋白质。其中一种被称为Kv1.3的通道在白细胞中表达，并被认为是治疗自身免疫性疾病的潜在新治疗靶点。我们提议的目的是在自身免疫性疾病和移植排斥的动物模型中测试我们设计的Kv1.3阻滞剂。

DESCRIPTION (provided by applicant): Specific K+ channel modulation offers an enormous potential for the development of new drugs. One channel that constitutes an especially promising therapeutic target is the voltage-gated Kv1.3 channel. Homomeric Kv1.3 channels are found in T and B lymphocytes and their expression is up-regulated in terminally differentiated effecter memory T (TEw) cells and class-switched memory B cells suggesting that Kv1.3 blockers should be useful for the treatment of autoimmune diseases such as multiple sclerosis, type-1 diabetes, psoriasis, contact dermatitis, rheumatoid arthritis and myasthenia gravis. This concept has been validated by the demonstration that autoreactive T cells from patients with multiple sclerosis and type-1 diabetes are predominantly Kv1.3-high TEM cells and that the Kv1.3 blocking peptide ShK can treat an animal model of multiple sclerosis. However, despite Kv1.3's obvious therapeutic importance, the pharmaceutical industry has so far been unsuccessful in developing selective and potent small molecule Kv1.3 blockers. With the alkoxypsoralen PAP-1 my laboratory recently identified the first small molecule inhibitor of Kv1.3 that blocks the channel with an EC50 of 2 nM and displays selectivity over the cardiac potassium channel Kv1.5. PAP-1 does not exhibit cytotoxic or phototoxic effects, is negative in the Ames test, potently inhibits the proliferation of human TEM cells and suppresses delayed type hypersensitivity (DTH), a TEM cell mediated reaction, in rats when administered intraperitoneally or orally. PAP-1 therefore seems to constitute an excellent new tool to further explore Kv1.3 as a target for immunosuppression and could potentially be developed into orally available immunomodulator. We the help of this proposal we intend to thoroughly explore the therapeutic potential of PAP-1. Under Aim-1 we will determine PAP-1's pharmacokinetics and test which effect long-term suppression of memory cells with PAP-1 has on the immune system. Under Aim 2 we will test whether PAP-1 treats allergic contact dermatitis, an animal model for CD8+ T cell mediated skin reactions like psoriasis, and experimental autoimmune myasthenia gravis, a model for the T-cell dependent antibody-mediated autoimmune disease myasthenia gravis. Since TEM cells also play an important role in early and late-stage transplant rejection we will further test whether PAP-1 can suppress acute and chronic rejection in a rat kidney transplant model (Aim 3). Lay: Potassium channels are proteins that tunnel the cell membrane and conduct potassium ions. One of these channels, called Kv1.3, is expressed in white blood cells and has been proposed as a potential new therapeutic target for the treatment of autoimmune diseases. The aims of our proposal are to test a Kv1.3 blocker that we designed in animal models of autoimmune diseases and transplant rejection.