作者:Julia Vennekamp、Heike Wulff、Christine Beeton、Peter A. Calabresi、Stephan Grissmer、Wolfram Hänsel、K. George Chandy
DOI:10.1124/mol.65.6.1364
日期:2004.6
The lymphocyte potassium channel Kv1.3 is widely regarded as a promising new target for immunosuppression. To identify a potent small-molecule Kv1.3 blocker, we synthesized a series of 5-phenylalkoxypsoralens and tested them by whole-cell patch clamp. The most potent compound of this series, 5-(4-phenylbutoxy)psoralen (Psora-4), blocked Kv1.3 in a use-dependent manner, with a Hill coefficient of 2 and an EC50 value of 3 nM, by preferentially binding to the C-type inactivated state of the channel. Psora-4 is the most potent small-molecule Kv1.3 blocker known. It exhibited 17- to 70-fold selectivity for Kv1.3 over closely related Kv1-family channels (Kv1.1, Kv1.2, Kv1.4, and Kv1.7) with the exception of Kv1.5 (EC50, 7.7 nM) and showed no effect on human ether-a-go-go -related channel, Kv3.1, the calcium-activated K+ channels (IKCa1, SK1-SK3, and BKCa), or the neuronal NaV1.2 channel. In a test of in vivo toxicity in rats, Psora-4 did not display any signs of acute toxicity after five daily subcutaneous injections at 33 mg/kg body weight. Psora-4 selectively suppressed the proliferation of human and rat myelin-specific effector memory T cells with EC50 values of 25 and 60 nM, respectively, without persistently suppressing peripheral blood naive and central memory T cells. Because autoantigen-specific effector memory T cells contribute to the pathogenesis of T cell-mediated autoimmune diseases such as multiple sclerosis, Psora-4 and other Kv1.3 blockers may be useful as immunomodulators for the therapy of autoimmune disorders.
淋巴细胞钾通道Kv1.3被广泛认为是一种有前景的免疫抑制新靶点。为了找到一种强效的小分子 Kv1.3 阻断剂,我们合成了一系列 5-苯基烷氧基补骨脂素,并通过全细胞膜片钳进行了测试。该系列中最有效的化合物--5-(4-苯基丁氧基)补骨脂素(Psora-4)通过优先与通道的 C 型失活状态结合,以使用依赖的方式阻断了 Kv1.3,希尔系数为 2,EC50 值为 3 nM。Psora-4 是已知最有效的小分子 Kv1.3 阻断剂。与密切相关的 Kv1 家族通道(Kv1.1、Kv1.2、Kv1.4 和 Kv1.7)相比,它对 Kv1.3 的选择性提高了 17 至 70 倍,但对 Kv1.5 的选择性除外(EC50 为 7.7 nM)之外,对人类醚-a-go-go 相关通道、Kv3.1、钙激活 K+通道(IKCa1、SK1-SK3 和 BKCa)或神经元 NaV1.2 通道均无影响。在大鼠体内毒性试验中,每天皮下注射五次 33 毫克/千克体重的 Psora-4 未显示任何急性毒性迹象。Psora-4 可选择性地抑制人和大鼠髓鞘特异性效应记忆 T 细胞的增殖,其 EC50 值分别为 25 和 60 nM,但不会持续抑制外周血幼稚和中枢记忆 T 细胞。由于自身抗原特异性效应记忆 T 细胞是 T 细胞介导的自身免疫性疾病(如多发性硬化症)的发病机制之一,因此 Psora-4 和其他 Kv1.3 阻断剂可用作治疗自身免疫性疾病的免疫调节剂。