Division of Nephrology, Department of Medicine, and Department of Physiology, Emory University , Atlanta, Georgia.
Research Service, Atlanta Veterans Affairs Medical Center , Atlanta, Georgia.
Am J Physiol Renal Physiol. 2019 Apr 1;316(4):F646-F653. doi: 10.1152/ajprenal.00487.2018. Epub 2019 Jan 16.
Zn deficiency (ZnD) is a common comorbidity of many chronic diseases. In these settings, ZnD exacerbates hypertension. Whether ZnD alone is sufficient to alter blood pressure (BP) is unknown. To explore the role of Zn in BP regulation, adult mice were fed a Zn-adequate (ZnA) or a Zn-deficient (ZnD) diet. A subset of ZnD mice were either returned to the ZnA diet or treated with hydrochlorothiazide (HCTZ), a Na-Cl cotransporter (NCC) inhibitor. To reduce intracellular Zn in vitro, mouse distal convoluted tubule cells were cultured in N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN, a Zn chelator)- or vehicle (DMSO)-containing medium. To replete intracellular Zn, TPEN-exposed cells were then cultured in Zn-supplemented medium. ZnD promoted a biphasic BP response, characterized by episodes of high BP. BP increases were accompanied by reduced renal Na excretion and NCC upregulation. These effects were reversed in Zn-replete mice. Likewise, HCTZ stimulated natriuresis and reversed BP increases. In vitro, Zn depletion increased NCC expression. Furthermore, TPEN promoted NCC surface localization and Na uptake activity. Zn repletion reversed TPEN effects on NCC. These data indicate that 1) Zn contributes to BP regulation via modulation of renal Na transport, 2) renal NCC mediates ZnD-induced hypertension, and 3) NCC is a Zn-regulated transporter that is upregulated with ZnD. This study links dysregulated renal Na handling to ZnD-induced hypertension. Furthermore, NCC is identified as a novel mechanism by which Zn regulates BP. Understanding the mechanisms of ZnD-induced BP dysregulation may have an important therapeutic impact on hypertension.
锌缺乏症(ZnD)是许多慢性疾病的常见合并症。在这些情况下,ZnD 会加重高血压。单独的 ZnD 是否足以改变血压(BP)尚不清楚。为了探讨 Zn 在血压调节中的作用,成年小鼠分别喂食 Zn 充足(ZnA)或 Zn 缺乏(ZnD)饮食。一部分 ZnD 小鼠被重新喂食 ZnA 饮食或用氢氯噻嗪(HCTZ)治疗,HCTZ 是一种钠氯共转运体(NCC)抑制剂。为了减少体外细胞内 Zn,将小鼠远曲小管细胞在含有 N,N,N',N'-四(2-吡啶基甲基)乙二胺(TPEN,一种 Zn 螯合剂)或载体(DMSO)的培养基中培养。为了补充细胞内 Zn,然后将暴露于 TPEN 的细胞在补充 Zn 的培养基中培养。ZnD 促进了双相血压反应,表现为高血压发作。血压升高伴随着肾钠排泄减少和 NCC 上调。这些影响在 Zn 充足的小鼠中得到逆转。同样,HCTZ 刺激了排钠作用并逆转了血压升高。在体外,Zn 耗竭增加了 NCC 的表达。此外,TPEN 促进了 NCC 的表面定位和 Na 摄取活性。Zn 补充逆转了 TPEN 对 NCC 的影响。这些数据表明 1)Zn 通过调节肾脏 Na 转运来参与血压调节,2)肾脏 NCC 介导 ZnD 诱导的高血压,3)NCC 是一种受 Zn 调节的转运蛋白,随着 ZnD 而上调。这项研究将肾脏 Na 处理失调与 ZnD 诱导的高血压联系起来。此外,NCC 被确定为 Zn 调节 BP 的一种新机制。了解 ZnD 诱导的 BP 失调的机制可能对高血压的治疗具有重要的影响。