Reihe Casey A, Pekas Nickolas, Wu Penglong, Wang Xuejun
Division of Basic Biomedical Science, Sanford School of Medicine of The University of South DakotaSD 57069, USA.
Department of Pathophysiology, Guangzhou Medical University College of Basic SciencesGuangzhou, Guangdong, China.
Am J Cardiovasc Dis. 2017 Dec 20;7(6):134-150. eCollection 2017.
Beyond helping the cell survive from energy starvation via self-eating a portion of cytoplasm, macroautophagy is also capable of targeted removal of defective organelles or cytoplasmic aberrant protein aggregates, thereby playing an important role in quality control in the cell. Impaired or suppressed macroautophagy activity is associated with the progression from a large subset of heart diseases to heart failure and with the development of the vast majority of, if not all, neurodegenerative diseases, the leading causes of death and disability in humans. Hence, a better understanding of the impact of existing and upcoming pharmacotherapies on macroautophagy in the heart and brain will undoubtedly benefit the search for safer and more effective treatment to improve human health. Neddylation is a recently recognized posttranslational modification process that modifies a subset of cellular proteins and is, by virtue of regulating Cullin-RING ligases, essential to ~20% ubiquitin-proteasome system (UPS)-mediated protein degradation. MLN4924 (Pevonedistat), a specific inhibitor of neddylation that promises to become a new anti-malignancy agent, is capable of inhibiting UPS-mediated progression of the cell cycle and activating macroautophagy in cancer cells. However, no reported study has tested the impact of systemic inhibition of neddylation on autophagic activity in a post-mitotic organ such as the heart and brain. This study was conducted to fill this gap. Sixteen GFP-LC3 transgenic mice of mixed sexes were divided equally into either MLN4924-treated or vehicle-treated groups and were treated respectively with MLN4924 (30 mg/kg, , twice a day × 3 days) or equal volume of solvent. The resultant changes in myocardial levels of neddylated cullin 1 as well as autophagic flux in cardiac and brain tissues were assessed. The effectiveness of the MLN4924 regime was verified by myocardial accumulation of neddylated cullin 1. Myocardial LC3-II flux and free GFP levels were comparable between the MLN4924 and the vehicle groups whereas the protein level of p62, substrate of macroautophagy, in the brain was significantly decreased by the MLN4924 treatment. Our data suggest that systemic inhibition of neddylation by a 3-day MLN4924 treatment regime does not suppress macroautophagy activities in the heart and brain.
除了通过自噬一部分细胞质帮助细胞在能量饥饿中存活外，巨自噬还能够靶向清除有缺陷的细胞器或细胞质异常蛋白聚集体，从而在细胞质量控制中发挥重要作用。巨自噬活性受损或受到抑制与从大量心脏病发展为心力衰竭以及绝大多数（如果不是全部）神经退行性疾病（人类死亡和残疾的主要原因）的进展有关。因此，更好地了解现有和即将出现的药物疗法对心脏和大脑中巨自噬的影响无疑将有助于寻找更安全、更有效的治疗方法来改善人类健康。Neddylation是一种最近被认识的翻译后修饰过程，它修饰一部分细胞蛋白，并且通过调节Cullin-RING连接酶对于约20%的泛素-蛋白酶体系统（UPS）介导的蛋白降解至关重要。MLN4924（培沃替尼）是一种neddylation的特异性抑制剂，有望成为一种新的抗癌药物，它能够抑制UPS介导的细胞周期进程并激活癌细胞中的巨自噬。然而，尚无报道研究测试全身性抑制neddylation对诸如心脏和大脑等有丝分裂后器官中自噬活性的影响。本研究旨在填补这一空白。将16只雌雄混合的GFP-LC3转基因小鼠平均分为MLN4924治疗组或溶剂对照组，分别用MLN4924（30mg/kg，每天两次，共3天）或等体积的溶剂进行治疗。评估心肌中neddylated cullin 1水平以及心脏和脑组织中自噬通量的相应变化。通过心肌中neddylated cullin 1的积累验证了MLN4924治疗方案的有效性。MLN4924组和溶剂对照组之间心肌LC3-II通量和游离GFP水平相当，而MLN4924治疗使大脑中巨自噬底物p62的蛋白水平显著降低。我们的数据表明，为期3天的MLN4924治疗方案全身性抑制neddylation不会抑制心脏和大脑中的巨自噬活性。
