Hyperphosphatemia-induced degradation of transcription factor EB exacerbates vascular calcification
Hyperphosphatemia-induced degradation of transcription factor EB exacerbates vascular calcification
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DOI：
10.1016/j.bbadis.2021.166323
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发表时间：
2022-03-01
影响因子：
6.2
通讯作者：
Morimoto, Yuji
中科院分区：
文献类型：
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作者：
Ishiwata, Ryo;Morimoto, Yuji
目的：慢性肾脏疾病(CKD)和随后的高磷血症导致血管钙化(VC)，这是一个强有力的死亡率预测因子。血管平滑肌细胞(VSMCs)自噬-溶酶体途径的失调介导了高磷血症依赖的VC。然而，溶酶体变得功能失调的过程仍不清楚。转录因子EB(TFEB)是溶酶体生物发生的主要调节因子。本研究检验了TFEB功能障碍导致VC进展的假说。方法和结果：无机磷(PI)可剂量依赖性地促进体外培养的小鼠主动脉、大鼠VSMCs和体外培养的人主动脉平滑肌细胞中Vc的表达，并伴有TFEB蛋白的降低。溶酶体抑制剂或使用小干扰RNA敲除TFEB可加重PI诱导的VSMC中的VC。相反，在过量维生素D诱导的高钙血症敏感型VC模型中，未观察到TFEB下调。给大鼠喂食含腺嘌呤的食物会导致慢性肾脏病和高磷血症。进食腺嘌呤的大鼠主动脉出现Vc，停用腺嘌呤后Vc消退。在此CKD模型中，主动脉TFEB的表达在VC开始时降低，但在停用腺嘌呤后从VC恢复到平均水平。CKD大鼠主动脉钙化区域表现为溶酶体损伤和TFEB泛素化增强。体外高磷可增加VSMC中不溶性TFEB和降低可溶性TFEB，这两种作用均可被蛋白酶体抑制剂MG-132所阻断。结论：高磷血症通过下调血管内皮细胞TFEB表达而致血管内皮细胞损伤。在高磷血症条件下，TFEB通过泛素-蛋白酶体系统被不溶解和降解。我们的结果为CKD和高磷血症下VC的发病机制提供了新的机制。
Aims: Chronic kidney disease (CKD) and subsequent hyperphosphatemia causes vascular calcification (VC), a strong predictor of mortality. Dysregulation of the autophagy-lysosomal pathway in vascular smooth muscle cells (VSMCs) mediates hyperphosphatemia-dependent VC. However, the process through which lysosomes become dysfunctional remains unknown. Transcription factor EB (TFEB) is a master regulator of lysosome biogenesis. The present study examined the hypothesis that TFEB dysfunction causes VC progression. Methods and results: Inorganic phosphate (Pi) dose-dependently promoted VC in mouse aorta ex vivo, in rat VSMCs in vitro, and in human aortic smooth muscle cells in vitro, all accompanied by a decrease in TFEB protein. Lysosomal inhibitors or TFEB knockdown using small interfering RNA exacerbated Pi-induced VC in VSMCs. Conversely, TFEB downregulation was not observed in the hypercalcemia-sensitive VC model induced by excessive vitamin D dosages. Feeding rats an adenine-containing diet caused CKD and hyperphosphatemia. VC occurred in the adenine-fed rat aorta and regressed after adenine cessation. In this CKD model, aortic TFEB expression decreased at VC onset but recovered to average levels during recovery from VC after adenine cessation. The calcified area of the CKD rat aorta exhibited lysosomal damage and enhanced TFEB ubiquitination. Hyperphosphatemia in vitro increased insoluble TFEB and decreased soluble TFEB in VSMCs, both of which were abrogated by the proteasome inhibitor, MG-132. Conclusion: Hyperphosphatemia caused VC via TFEB downregulation in VSMCs. Under hyperphosphatemia, TFEB was insolubilized and degraded via the ubiquitin-proteasome system. Our results suggest a new mechanism for the pathogenesis of VC under CKD and hyperphosphatemia.