Impaired natriuretic response to high-NaCl diet plus aldosterone infusion in mice overexpressing human CD39, an ectonucleotidase (NTPDase1).
Impaired natriuretic response to high-NaCl diet plus aldosterone infusion in mice overexpressing human CD39, an ectonucleotidase (NTPDase1).
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过度表达人 CD39（一种核酸外切酶 (NTPDase1)）的小鼠对高 NaCl 饮食加醛固酮输注的利尿钠反应受损。
DOI：
10.1152/ajprenal.00125.2014
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Ecelbarger,CarolynM
中科院分区：
文献类型：
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作者：
Zhang,Yue;Robson,SimonC;Morris,KaiyaL;Heiney,KristinaM;Dwyer,KarenM;Kishore,BellamkondaK;Ecelbarger,CarolynM
细胞外核苷酸通过P2受体促进尿钠排泄。为了确定嘌呤能机制如何参与钠稳态，我们使用了全球过度表达人CD 39（hCD 39，NTPDase 1）的转基因（TG）小鼠，这是一种将细胞外ATP/ADP水解为AMP的外核苷酸酶，导致细胞外嘌呤谱改变。在高钠饮食（HSD，3.5%Na+），尿量和血清钠显着较高的TG小鼠，但钠排泄量不变。此外，TG小鼠表现出与HSD的尿醛固酮衰减下降。Western blot分析显示，TG小鼠髓质中上皮钠通道β亚基（ENaC）的密度显著降低（约40%），皮质中γ-ENaC的主带（85-kDa）显著增加。为了评估醛固酮非依赖性差异，在第二个实验中，通过渗透微型泵以20 μg/天的剂量夹紧醛固酮，并给小鼠喂食HSD或低钠饮食（LSD，0.03%Na+）。在这里，没有发现尿量或渗透压，或血清醛固酮的差异，但TG小鼠表现出适度的，但在晚期尿钠排泄（第3和第4天）显着的损害。几个主要的钠转运蛋白或通道亚基的基因型之间的差异表达。HSD导致两种基因型的Na-Cl协同转运蛋白（NCC）下调，并使NCC、Na-K-ATP酶（α-1亚基）、α-和γ-ENaC的皮质水平升高。Na-K-2Cl协同转运蛋白（NKCC 2）在野生型小鼠中被HSD下调，但在TG小鼠中增加。总之，我们的数据支持细胞外核苷酸促进尿钠排泄的概念;它们还揭示了嘌呤能信号传导对主要肾钠转运蛋白和通道亚基的醛固酮非依赖性下调。
Extracellular nucleotides acting through P2 receptors facilitate natriuresis. To define how purinergic mechanisms are involved in sodium homeostasis, we used transgenic (TG) mice that globally overexpress human CD39 (hCD39, NTPDase1), an ectonucleotidase that hydrolyzes extracellular ATP/ADP to AMP, resulting in an altered extracellular purine profile. On a high-sodium diet (HSD, 3.5% Na+), urine volume and serum sodium were significantly higher in TG mice but sodium excretion was unaltered. Furthermore, TG mice showed an attenuated fall in urine aldosterone with HSD. Western blot analysis revealed significantly lower densities (∼40%) of the β-subunit of the epithelial sodium channel (ENaC) in medulla, and the major band (85-kDa) of γ-ENaC in TG mice cortex. To evaluate aldosterone-independent differences, in a second experiment, aldosterone was clamped by osmotic minipump at 20 μg/day, and mice were fed either an HSD or a low-sodium diet (LSD, 0.03% Na+). Here, no differences in urine volume or osmolality, or serum aldosterone were found, but TG mice showed a modest, yet significant impairment in late natriuresis (days 3and4). Several major sodium transporters or channel subunits were differentially expressed between the genotypes. HSD caused a downregulation of Na-Cl cotransporter (NCC) in both genotypes; and had higher cortical levels of NCC, Na-K-ATPase (α-1 subunit), and α- and γ-ENaC. The Na-K-2Cl cotransporter (NKCC2) was downregulated by HSD in wild-type mice, but it increased in TG mice. In summary, our data support the concept that extracellular nucleotides facilitate natriuresis; they also reveal an aldosterone-independent downregulation of major renal sodium transporters and channel subunits by purinergic signaling.