张 乐, 刘 敏, 马 颖, 胡建华, 纪兆乐, 马 恒, 李 妍. 衰老心肌自噬减退的新机制-转录因子EB的关键作用[J]. 心脏杂志, 2015, 27(5): 497-500.
    引用本文: 张 乐, 刘 敏, 马 颖, 胡建华, 纪兆乐, 马 恒, 李 妍. 衰老心肌自噬减退的新机制-转录因子EB的关键作用[J]. 心脏杂志, 2015, 27(5): 497-500.
    New mechanism of age-related myocardial autophagy decline: Key role of transcription factor EB[J]. Chinese Heart Journal, 2015, 27(5): 497-500.
    Citation: New mechanism of age-related myocardial autophagy decline: Key role of transcription factor EB[J]. Chinese Heart Journal, 2015, 27(5): 497-500.

    衰老心肌自噬减退的新机制-转录因子EB的关键作用

    New mechanism of age-related myocardial autophagy decline: Key role of transcription factor EB

    • 摘要: 目的 探讨转录因子EB(TFEB)在衰老心肌自噬减退中的作用。方法 采用老年(22月龄)雄性C57BL/6小鼠为实验对象,以成年(4月龄)雄性C57BL/6小鼠为对照,分析心肌自噬水平、心肌TFEB表达水平。结果 与成年心肌相比,衰老心肌自噬水平显著降低(P<0.05)。衰老心肌中自噬体标志物Atg5、LC3和Beclin-1,溶酶体标志物LAMP1在蛋白和mRNA水平上均出现降低。与成年心肌相比,衰老心肌TFEB蛋白水平显著降低(P<0.05),衰老心肌细胞核内的TFEB水平下降更为显著(P<0.05),提示衰老心肌TFEB转录能力减退。给予小剂量雷帕霉素处理,可提高衰老心肌细胞核内TFEB水平,并且改善LC3及LAMP1的mRNA和蛋白水平,提高衰老心肌自噬水平。结论 本研究发现衰老导致的心肌TFEB水平降低严重影响心肌自噬能力,提示TFEB是心肌自噬增龄性减退机制中的关键调节因子。

       

      Abstract: AIM To explore the role of transcription factor EB (TFEB) in myocardial autophagic decline with aging. METHODS Age-related autophagic and TFEB changes in male C57BL/6 young (4 mo) and aged (22 mo) mice were analyzed. RESULTS Compared with young hearts, the aged heart had a lower level of autophagy (P<0.05). The autophagic markers including Atg5, LC3, Beclin-1 and lysosomal maker LAMP1 decreased in both protein and gene in the aged heart (P<0.05). In addition, cardiomyocyte TFEB, especially in cardiomyocyte nuclei, was significantly reduced in the aged heart (P<0.05), demonstrating that transcriptional activity of cardiomyocyte TFEB declined with aging. Systemic treatment with rapamycin in aged heart partly improved cardiomyocyte nuclear TFEB and autophagy as evidenced by increased autophagosome LC3-II level and increased lysosome LAMP1 level (P<0.05). CONCLUSION We demonstrate that age-related myocardial TFEB decreases significantly affects cardiomyocyte autophagy. TFEB is the key regulatory point of aging-associated myocardial autophagy decline.

       

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