Department of Neurologic Surgery, Indiana University School of Medicine, Indianapolis, Indiana (W.X., X.P., R.C., X.J.); Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin (J.M.W., G.L., L.K.G., F.R., R.J., J.M.C.); Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, Indiana (W.X., X.P., X.J.); and Laboratory of Antiepileptic Drug Discovery, St. Vincent's Hospital, Indianapolis, Indiana (J.L.S.)
Department of Neurologic Surgery, Indiana University School of Medicine, Indianapolis, Indiana (W.X., X.P., R.C., X.J.); Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin (J.M.W., G.L., L.K.G., F.R., R.J., J.M.C.); Department of Anatomy, Cell Biology, and Physiology, Indiana University School of Medicine, Indianapolis, Indiana (W.X., X.P., X.J.); and Laboratory of Antiepileptic Drug Discovery, St. Vincent's Hospital, Indianapolis, Indiana (J.L.S.).
J Pharmacol Exp Ther. 2020 Jan;372(1):83-94. doi: 10.1124/jpet.119.260968. Epub 2019 Nov 6.
The imidizodiazepine, 5-(8-ethynyl-6-(pyridin-2-yl)-4-benzo[]imidazo[1,5-][1,4]diazepin-3-yl)oxazole (KRM-II-81), is selective for 2/3-containing GABA receptors. KRM-II-81 dampens seizure activity in rodent models with enhanced efficacy and reduced motor-impairment compared with diazepam. In the present study, KRM-II-81 was studied in assays designed to detect antiepileptics with improved chances of impacting pharmaco-resistant epilepsies. The potential for reducing neural hyperactivity weeks after traumatic brain injury was also studied. KRM-II-81 suppressed convulsions in corneal-kindled mice. Mice with kainate-induced mesial temporal lobe seizures exhibited spontaneous recurrent hippocampal paroxysmal discharges that were significantly reduced by KRM-II-81 (15 mg/kg, orally). KRM-II-81 also decreased convulsions in rats undergoing amygdala kindling in the presence of lamotrigine (lamotrigine-insensitive model) (ED = 19 mg/kg, i.p.). KRM-II-81 reduced focal and generalized seizures in a kainate-induced chronic epilepsy model in rats (20 mg/kg, i.p., three times per day). In mice with damage to the left cerebral cortex by controlled-cortical impact, enduring neuronal hyperactivity was dampened by KRM-II-81 (10 mg/kg, i.p.) as observed through in vivo two-photon imaging of layer II/III pyramidal neurons in GCaMP6-expressing transgenic mice. No notable side effects emerged up to doses of 300 mg/kg KRM-II-81. Molecular modeling studies were conducted: docking in the binding site of the 132L GABA receptor showed that replacing the C8 chlorine atom of alprazolam with the acetylene of KRM-II-81 led to loss of the key interaction with 1His102, providing a structural rationale for its low affinity for 1-containing GABA receptors compared with benzodiazepines such as alprazolam. Overall, these findings predict that KRM-II-81 has improved therapeutic potential for epilepsy and post-traumatic epilepsy. SIGNIFICANCE STATEMENT: We describe the effects of a relatively new orally bioavailable small molecule in rodent models of pharmaco-resistant epilepsy and traumatic brain injury. KRM-II-81 is more potent and generally more efficacious than standard-of-care antiepileptics. In silico docking experiments begin to describe the structural basis for the relative lack of motor impairment induced by KRM-II-81. KRM-II-81 has unique structural and anticonvulsant effects, predicting its potential as an improved antiepileptic drug and novel therapy for post-traumatic epilepsy.
5-(8-乙炔基-6-(吡啶-2-基)-4-苯并[]咪唑并[1,5-][1,4]二氮杂*-3-基)恶唑的咪唑并二氮杂*(KRM-II-81)对 2/3 型 GABA 受体具有选择性。与地西泮相比,KRM-II-81 可减轻啮齿动物模型中的癫痫发作活动,且疗效增强,运动障碍减轻。在本研究中,研究了 KRM-II-81 在旨在检测具有改善影响药物难治性癫痫机会的抗癫痫药物的测定中。还研究了在创伤性脑损伤后数周内减轻神经过度兴奋的潜力。KRM-II-81 抑制角膜点燃小鼠的惊厥。用红藻氨酸诱导的内侧颞叶癫痫发作的小鼠表现出自发性复发性海马阵发性放电,KRM-II-81(15mg/kg,口服)显著减少了这种放电。KRM-II-81 还降低了在左杏仁核点燃存在拉莫三嗪的大鼠中的惊厥发作(拉莫三嗪不敏感模型)(ED=19mg/kg,ip)。KRM-II-81 还降低了大鼠中红藻氨酸诱导的慢性癫痫模型中的局灶性和全身性癫痫发作(20mg/kg,ip,每天 3 次)。在通过对左侧大脑皮层进行控制性皮质撞击的小鼠中,KRM-II-81(10mg/kg,ip)减弱了神经元的持续过度兴奋,通过在表达 GCaMP6 的转基因小鼠中进行活体双光子成像观察到了这一点。高达 300mg/kg KRM-II-81 的剂量都没有出现明显的副作用。进行了分子建模研究:在 132L GABA 受体的结合位点对接表明,用 KRM-II-81 的乙炔取代阿普唑仑的 C8 氯原子导致与 1His102 的关键相互作用丧失,从而为其与苯并二氮杂*(如阿普唑仑)相比对 1 型 GABA 受体的低亲和力提供了结构依据。总的来说,这些发现预示着 KRM-II-81 具有改善癫痫和创伤后癫痫的治疗潜力。意义陈述:我们描述了一种相对较新的、可口服生物利用的小分子在药物难治性癫痫和创伤性脑损伤的啮齿动物模型中的作用。KRM-II-81 比标准治疗抗癫痫药更有效,且通常更有效。基于计算机的对接实验开始描述 KRM-II-81 引起的运动障碍相对较少的结构基础。KRM-II-81 具有独特的结构和抗惊厥作用,预示着它作为一种改良的抗癫痫药物和治疗创伤后癫痫的新疗法的潜力。