Renal sodium transporter/channel expression and sodium excretion in P2Y2 receptor knockout mice fed a high-NaCl diet with/without aldosterone infusion.
Renal sodium transporter/channel expression and sodium excretion in P2Y2 receptor knockout mice fed a high-NaCl diet with/without aldosterone infusion.
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DOI：
10.1152/ajprenal.00549.2010
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发表时间：
2011-03
期刊：
影响因子：
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通讯作者：
Yue Zhang;R. Listhrop;C. Ecelbarger;B. Kishore
中科院分区：
文献类型：
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作者：
Yue Zhang;R. Listhrop;C. Ecelbarger;B. Kishore
P2 Y（2）受体（P2 Y2-R）拮抗肾脏中的钠重吸收。除了对远端肾单位的影响外，假设P2 Y（2）-R可能通过拮抗醛固酮或加压素或与一氧化氮（NO）和前列腺素E（2）（PGE（2））或氧化应激（OS）等介质的相互作用来调节沿着肾单位的钠转运蛋白/通道亚基的活性/丰度。为了确定P2 Y（2）-R在肾钠重吸收中的调节作用的程度，在研究1中，我们给P2 Y（2）-R敲除（KO; n = 5）和野生型（WT; n = 5）小鼠喂食高（3.15%）钠饮食（HSD）14天。Western印迹显示KO小鼠皮质和髓质布美他尼敏感性Na-K-2Cl协同转运蛋白（NKCC 2）、髓质Na-K-ATP酶α-1亚基和髓质上皮钠通道α亚基（ENaC）的蛋白丰度显著高于WT小鼠。尿液的分子分析显示，相对于WT小鼠，KO小鼠中硝酸盐加亚硝酸盐（NOx）、PGE（2）和8-异前列烷的排泄增加，支持这些分子在确定参与钠沿着肾单位转运的蛋白质改变中的假定作用。为了确定对醛固酮反应的基因型差异是否可能在HSD引起的这些差异中发挥作用，在研究2中，对醛固酮水平进行了钳制（通过渗透压微型泵输注）。与WT小鼠相比，夹闭醛固酮（与HSD）导致尿钠排泄显著受损，皮质中Na/H交换亚型3升高，髓质中NKCC 2升高，皮质中NKCC 2、α-和β-ENaC水平适度但显著降低。这与KO中尿NOx的显著减少有关，尽管与WT小鼠相比，PGE（2）和8-异前列烷仍然显著升高。综上所述，我们的研究结果表明，P2 Y（2）-R是一个重要的调节钠转运沿着肾单位。前或后受体的差异，可能介导的反应，醛固酮，通过肾上腺素或NOS活性或OS的变化，可能发挥作用。
The P2Y(2) receptor (P2Y2-R) antagonizes sodium reabsorption in the kidney. Apart from its effect in distal nephron, hypothetically, P2Y(2)-R may modulate activity/abundances of sodium transporters/channel subunits along the nephron via antagonism of aldosterone or vasopressin or interaction with mediators such as nitric oxide (NO), and prostaglandin E(2) (PGE(2)) or oxidative stress (OS). To determine the extent of the regulatory role of P2Y(2)-R in renal sodium reabsorption, in study 1, we fed P2Y(2)-R knockout (KO; n = 5) and wild-type (WT; n = 5) mice a high (3.15%)-sodium diet (HSD) for 14 days. Western blotting revealed significantly higher protein abundances for cortical and medullary bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2), medullary α-1-subunit of Na-K-ATPase, and medullary α-subunit of the epithelial sodium channel (ENaC) in KO vs. WT mice. Molecular analysis of urine showed increased excretion of nitrates plus nitrites (NOx), PGE(2), and 8-isoprostane in the KO, relative to WT mice, supporting a putative role for these molecules in determining alterations of proteins involved in sodium transport along the nephron. To determine whether genotype differences in response to aldosterone might have played a role in these differences due to HSD, in study 2 aldosterone levels were clamped (by osmotic minipump infusion). Clamping aldosterone (with HSD) led to significantly impaired natriuresis with elevated Na/H exchanger isoform 3 in the cortex, and NKCC2 in the medulla, and modest but significantly lower levels of NKCC2, and α- and β-ENaC in the cortex of KO vs. WT mice. This was associated with significantly reduced urinary NOx in the KO, although PGE(2) and 8-isoprostane remained significantly elevated vs. WT mice. Taken together, our results suggest that P2Y(2)-R is an important regulator of sodium transporters along the nephron. Pre- or postreceptor differences in the response to aldosterone, perhaps mediated via prostaglandins or changes in NOS activity or OS, likely play a role.