Floto R Andres, Sarkar Sovan, Perlstein Ethan O, Kampmann Beate, Schreiber Stuart L, Rubinsztein David C
Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, UK.
Autophagy. 2007 Nov-Dec;3(6):620-2. doi: 10.4161/auto.4898. Epub 2007 Aug 16.
Upregulation of autophagy may have therapeutic benefit in a range of diseases that includes neurodegenerative conditions caused by intracytosolic aggregate-prone proteins, such as Huntington's disease, and certain infectious diseases, such as tuberculosis. The best-characterized drug that enhances autophagy is rapamycin, an inhibitor of the TOR (target of rapamycin) proteins, which are widely conserved from yeast to man. Unfortunately, the side effects of rapamycin, especially immunosuppression, preclude its use in treating certain diseases including tuberculosis, which accounts for approximately 2 million deaths worldwide each year, spurring interest in finding novel drugs that selectively enhance autophagy. We have recently reported a novel two-step screening process for the discovery of such compounds. We first identified compounds that enhance the growth-inhibitory effects of rapamycin in the budding yeast Saccharomyces cerevisiae, which we termed small molecule enhancers of rapamycin (SMERs). Next we showed that three SMERs induced autophagy independently, or downstream of mTOR, in mammalian cells, and furthermore enhanced the clearance of a mutant huntingtin fragment in Huntington's disease cell models. These SMERs also protected against mutant huntingtin fragment toxicity in Drosophila. We have subsequently tested two of the SMERs in models of tuberculosis and both enhance the killing of mycobacteria by primary human macrophages.
自噬上调可能对一系列疾病具有治疗益处,这些疾病包括由细胞内易形成聚集体的蛋白质引起的神经退行性疾病,如亨廷顿舞蹈症,以及某些传染病,如结核病。最具代表性的增强自噬的药物是雷帕霉素,它是雷帕霉素靶蛋白(TOR)的抑制剂,从酵母到人类广泛保守。不幸的是,雷帕霉素的副作用,尤其是免疫抑制作用,使其无法用于治疗包括结核病在内的某些疾病,结核病每年在全球导致约200万人死亡,这激发了人们寻找选择性增强自噬的新型药物的兴趣。我们最近报道了一种用于发现此类化合物的新型两步筛选方法。我们首先鉴定出能增强雷帕霉素对出芽酵母酿酒酵母生长抑制作用的化合物,我们将其称为雷帕霉素小分子增强剂(SMERs)。接下来我们表明,三种SMERs在哺乳动物细胞中独立诱导自噬,或在mTOR下游诱导自噬,并且在亨廷顿舞蹈症细胞模型中进一步增强了突变型亨廷顿蛋白片段的清除。这些SMERs在果蝇中也能保护细胞免受突变型亨廷顿蛋白片段的毒性作用。我们随后在结核病模型中测试了其中两种SMERs,它们都能增强原代人巨噬细胞对分枝杆菌的杀伤作用。