Abstract：
ZFYVE21 is an ancient, endosome-associated protein that is highly expressed in endothelial cells (ECs) but whose function(s) in vivo are undefined. Here, we identified ZFYVE21 as an essential regulator of vascular barrier function in the aging kidney. ZFYVE21 levels significantly decline in ECs in aged human and mouse kidneys. To investigate attendant effects, we generated EC-specific Zfyve21-/- reporter mice. These knockout mice developed accelerated aging phenotypes including reduced endothelial nitric oxide (ENOS) activity, failure to thrive, and kidney insufficiency. Kidneys from Zfyve21 EC-/- mice showed interstitial edema and glomerular EC injury. ZFYVE21-mediated phenotypes were not programmed developmentally as loss of ZFYVE21 in ECs during adulthood phenocopied its loss prenatally, and a nitric oxide donor normalized kidney function in adult hosts. Using live cell imaging and human kidney organ cultures, we found that in a GTPase Rab5- and protein kinase Akt-dependent manner, ZFYVE21 reduced vesicular levels of inhibitory caveolin-1 and promoted transfer of Golgi-derived ENOS to a perinuclear Rab5+ vesicular population to functionally sustain ENOS activity. Thus, our work defines a ZFYVE21- mediated trafficking mechanism sustaining ENOS activity and demonstrates the relevance of this pathway for maintaining kidney function with aging.
摘要：
ZFYVE21是一个古老的，在内皮细胞（ECs）中高度表达但其体内功能未定义的内体相关蛋白。这里,我们确定ZFYVE21是衰老肾脏血管屏障功能的重要调节因子.ZFYVE21水平在老年人和小鼠肾脏中的ECs中显著下降。为了调查随之而来的影响，我们产生了EC特异性ZFVYE21-/-报告小鼠。这些基因敲除小鼠出现加速衰老的表型，包括内皮一氧化氮（ENOS）活性降低，未能茁壮成长，和肾功能不全。ZFYVE21EC-/-小鼠的肾脏显示间质水肿和肾小球EC损伤。ZFYVE21介导的表型在发育上没有编程，因为在成年期间EC中ZFYVE21的丢失在产前出现，一氧化氮供体使成年宿主的肾功能正常化。使用活细胞成像和人体肾脏器官培养，我们发现GTPaseRab5-和蛋白激酶Akt依赖性方式，ZFYVE21降低了抑制性小窝蛋白1的囊泡水平，并促进了高尔基衍生的ENOS转移到核周Rab5囊泡群以在功能上维持ENOS活性。因此，我们的工作定义了ZFYVE21介导的维持ENOS活性的转运机制,并证明了该途径与衰老时维持肾功能的相关性.
