N-substituted phenylbenzamides of the niclosamide chemotype attenuate obesity related changes in high fat diet fed mice

Obesity and insulin resistance are primary risk factors for Non-Alcoholic Fatty Liver Disease (NAFLD). NAFLD is generally exhibited by non-progressive simple steatosis. However, a significant subset of patient’s progress to nonalcoholic steatohepatitis (NASH) that is defined by the presence of steatosis, inflammation and hepatocyte injury with fibrosis. Unfortunately, there are no approved therapies for NAFLD or NASH and therefore therapeutic approaches are urgently needed. Niclosamide is an U.S. Food and Drug Administration (FDA)-approved anthelmintic drug that mediates its effect by uncoupling oxidative phosphorylation. Niclosamide and its salt forms, Niclosamide Ethanolamine (NEN), and Niclosamide Piperazine (NPP) have shown efficacy in murine models of diet induced obesity characterized by attenuation of the prominent fatty liver disease phenotype and improved glucose metabolism. While the exact mechanism(s) underlying these changes remains unclear, the ability to uncouple oxidative phosphorylation leading to increased energy expenditure and lipid metabolism or attenuation of PKA mediated glucagon signaling in the liver have been proposed. Unfortunately, niclosamide has very poor water solubility, leading to low oral bioavailability. This, in addition to mitochondrial uncoupling activity and potential genotoxicity have reduced enthusiasm for its clinical use. More recently, salt forms of niclosamide, NEN and NPP, have demonstrated improved oral bioavailability while retaining activity. This suggests that development of safer more effective niclosamide derivatives for the treatment of NAFLD and Type 2 Diabetes may be possible. Herein we explored the ability of a series of N-substituted phenylbenzamide derivatives of the niclosamide salicylanilide chemotype to attenuate hepatic steatosis using a novel phenotypic in vitro model of fatty liver and the high fat diet-fed mouse model of diet induced obesity. These studies identified novel compounds with improved pre-clinical properties that attenuate hepatic steatosis in vitro and in vivo. These compounds with improved drug properties may be useful in alleviating symptoms and protection against disease progression in patients with metabolic syndrome and NAFLD.肥胖与胰岛素抵抗是非酒精性脂肪性肝病（Non-Alcoholic Fatty Liver Disease, NAFLD）的主要危险因素。NAFLD通常表现为非进展性单纯性脂肪变性，但有相当比例的患者会进展为非酒精性脂肪性肝炎（Nonalcoholic Steatohepatitis, NASH）——该病以脂肪变性、炎症伴纤维化的肝细胞损伤为特征。目前尚无获批用于NAFLD或NASH的治疗方案，因此亟需开发新的治疗策略。 氯硝柳胺（Niclosamide）是美国食品药品监督管理局（U.S. Food and Drug Administration, FDA）批准的抗蠕虫药物，其通过解偶联氧化磷酸化发挥药效。氯硝柳胺及其盐形式——氯硝柳胺乙醇胺盐（Niclosamide Ethanolamine, NEN）与氯硝柳胺哌嗪盐（Niclosamide Piperazine, NPP）——在饮食诱导肥胖的小鼠模型中展现出治疗潜力，可显著改善脂肪肝表型并优化糖代谢状态。尽管上述改善的确切机制尚未阐明，但目前已提出两种潜在假说：一是通过解偶联氧化磷酸化增加能量消耗与脂质代谢，二是减弱肝脏中蛋白激酶A（Protein Kinase A, PKA）介导的胰高血糖素信号通路。 然而，氯硝柳胺水溶性极差，导致其口服生物利用度低下。此外，其线粒体解偶联活性与潜在的遗传毒性也限制了其临床应用的前景。近年来研究发现，氯硝柳胺的盐形式NEN与NPP可在保留药理活性的同时，提升口服生物利用度。这提示开发更安全、更高效的氯硝柳胺衍生物用于治疗NAFLD与2型糖尿病具备可行性。 本研究针对氯硝柳胺水杨酰苯胺（salicylanilide）化学型的一系列N-取代苯基苯甲酰胺衍生物，通过构建新型脂肪肝表型体外模型与高脂饮食诱导肥胖小鼠模型，探究其缓解肝脂肪变性的能力。研究筛选出了具备更优临床前特性的新型化合物，可在体外与体内实验中均减轻肝脂肪变性。这类具备更佳成药性的化合物或可用于缓解代谢综合征与NAFLD患者的症状，并延缓疾病进展。