背景:肾小管上皮细胞(RTEC)的衰老在糖尿病肾病(DKD)的进展中至关重要。越来越多的证据表明线粒体自噬不足与RTEC衰老密切相关。酵母线粒体逃逸1样1(YME1L),线粒体内膜金属蛋白酶,保持线粒体的完整性。其在DKD中的功能仍不清楚。这里,我们研究了YME1L是否可以通过调节线粒体自噬和细胞衰老来阻止DKD的进展。
方法:我们分析了YME1L在DKD患者和小鼠肾小管中的表达,探索与RTEC中YME1L过表达相关的转录组变化,并使用HFD/STZ诱导的DKD小鼠模型评估其对RTEC衰老和肾功能障碍的影响。通过使用重组腺相关病毒2/9(rAAV2/9)实现了YME1L的小管特异性过表达。我们进行了体内和体外实验,以评估YME1L过表达对线粒体自噬和线粒体功能的影响。此外,我们进行了LC-MS/MS分析,以鉴定涉及YME1L的潜在蛋白质相互作用,并阐明其潜在机制.
结果:我们的发现揭示了YME1L在DKD患者和小鼠肾小管中的表达显著降低。然而,在HFD/STZ诱导的DKD小鼠模型中,YME1L的小管特异性过表达可显着减轻RTEC衰老和肾功能障碍。此外,YME1L过表达对体内和体外增强线粒体自噬和改善线粒体功能均具有积极作用。机械上,我们的LC-MS/MS分析发现了一个关键的线粒体自噬受体,BCL2-like13(BCL2L13),作为YME1L的互动伙伴。此外,发现YME1L促进BCL2L13的磷酸化,突出了其在调节线粒体自噬中的作用。
结论:这项研究提供了令人信服的证据,表明YME1L在保护RTECs免受细胞衰老和阻碍DKD进展方面发挥着关键作用。YME1L的过表达通过改善DKD小鼠的RTEC衰老和肾功能障碍显示出显著的治疗潜力。此外,我们的发现表明YME1L增强线粒体自噬并改善线粒体功能,可能通过其与BCL2L13的相互作用和随后的磷酸化。这些对YME1L保护机制的新见解为开发针对DKD的疗法提供了有希望的策略。
BACKGROUND: The senescence of renal tubular epithelial cells (RTECs) is crucial in the progression of diabetic kidney disease (DKD). Accumulating evidence suggests a close association between insufficient mitophagy and RTEC senescence. Yeast mitochondrial escape 1-like 1 (YME1L), an inner mitochondrial membrane metalloprotease, maintains mitochondrial integrity. Its functions in DKD remain unclear. Here, we investigated whether YME1L can prevent the progression of DKD by regulating mitophagy and cellular senescence.
METHODS: We analyzed YME1L expression in renal tubules of DKD patients and mice, explored transcriptomic changes associated with YME1L overexpression in RTECs, and assessed its impact on RTEC senescence and renal dysfunction using an HFD/STZ-induced DKD mouse model. Tubule-specific overexpression of YME1L was achieved through the use of recombinant adeno-associated virus 2/9 (rAAV 2/9). We conducted both in vivo and in vitro experiments to evaluate the effects of YME1L overexpression on mitophagy and mitochondrial function. Furthermore, we performed LC-MS/MS analysis to identify potential protein interactions involving YME1L and elucidate the underlying mechanisms.
RESULTS: Our findings revealed a significant decrease in YME1L expression in the renal tubules of DKD patients and mice. However, tubule-specific overexpression of YME1L significantly alleviated RTEC senescence and renal dysfunction in the HFD/STZ-induced DKD mouse model. Moreover, YME1L overexpression exhibited positive effects on enhancing mitophagy and improving mitochondrial function both in vivo and in vitro. Mechanistically, our LC-MS/MS analysis uncovered a crucial mitophagy receptor, BCL2-like 13 (BCL2L13), as an interacting partner of YME1L. Furthermore, YME1L was found to promote the phosphorylation of BCL2L13, highlighting its role in regulating mitophagy.
CONCLUSIONS: This study provides compelling evidence that YME1L plays a critical role in protecting RTECs from cellular senescence and impeding the progression of DKD. Overexpression of YME1L demonstrated significant therapeutic potential by ameliorating both RTEC senescence and renal dysfunction in the DKD mice. Moreover, our findings indicate that YME1L enhances mitophagy and improves mitochondrial function, potentially through its interaction with BCL2L13 and subsequent phosphorylation. These novel insights into the protective mechanisms of YME1L offer a promising strategy for developing therapies targeting DKD.