Antispasmodic drug drofenine as an inhibitor of Kv2.1 channel ameliorates peripheral neuropathy in diabetic mice

Here, we report that the antispasmodic drug drofenine (Dfe) blocks Kv2.1 with an IC50 of 9.3 M, and in vivo treatment with Dfe suppresses mRNA and protein expression of Kv2.1 in DRG tissues of DPN mice and ameliorates DPN-like pathology. The underlying mechanisms have been intensively investigated by assay against the DPN mice with in vivo Kv2.1 knockdown injected with adeno associated virus AAV9-Kv2.1-RNAi. Streptozotocin (STZ) induced type 1 or db/db type 2 diabetic mice with DPN exhibited a high level of Kv2.1 protein in dorsal root ganglion (DRG) tissue and suppressed neurite outgrowth in DRG neuron. Dfe treatment promoted neurite outgrowth by inhibiting Kv2.1 channel. Moreover, it suppressed inflammation by repressing IB/NF-κB signaling, inhibited apoptosis by regulating Kv2.1-mediated Bcl-2 family proteins and Caspase 3 and ameliorated mitochondrial dysfunction through Kv2.1/CaMKKβ/AMPK/PGC1α pathway. Together, our work has strongly supported that Kv2.1 inhibition is a promising therapeutic strategy for DPN and highlighted the potential of Dfe in the treatment of this disease.

本研究报道，解痉药物多非那尼（drofenine, Dfe）以9.3 μM的半数抑制浓度（IC50）阻断钾离子通道Kv2.1；体内给予Dfe可抑制糖尿病周围神经病变（Diabetic Peripheral Neuropathy, DPN）小鼠背根神经节（dorsal root ganglion, DRG）组织中Kv2.1的mRNA与蛋白表达，并改善DPN样病理表型。本研究通过向DPN小鼠体内注射腺相关病毒（adeno-associated virus, AAV）介导的Kv2.1小干扰RNA载体（AAV9-Kv2.1-RNAi）开展体内Kv2.1敲低实验，对其潜在作用机制进行了深入探究。链脲佐菌素（Streptozotocin, STZ）诱导的1型糖尿病合并DPN小鼠，以及db/db遗传背景的2型糖尿病合并DPN小鼠，其背根神经节组织中Kv2.1蛋白水平显著升高，且背根神经节神经元的神经突起生长受到抑制。Dfe可通过抑制Kv2.1通道活性促进神经突起生长。此外，Dfe还可通过抑制IκBα/NF-κB信号通路减轻炎症反应，通过调控Kv2.1介导的Bcl-2家族蛋白与半胱氨酸天冬氨酸蛋白酶3（Caspase 3）的表达抑制细胞凋亡，并通过Kv2.1/CaMKKβ/AMPK/PGC1α通路改善线粒体功能障碍。综上，本研究充分证实抑制Kv2.1是治疗DPN的极具潜力的治疗策略，并凸显了Dfe在该疾病治疗中的应用前景。