NADPH oxidase and PKC contribute to increased Na transport by the thick ascending limb during type 1 diabetes.
NADPH oxidase and PKC contribute to increased Na transport by the thick ascending limb during type 1 diabetes.
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NADPH 氧化酶和 PKC 有助于增加 1 型糖尿病期间厚升肢的 Na 转运。
DOI：
10.1161/hypertensionaha.111.184796
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Carmines,PamelaK
中科院分区：
文献类型：
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作者：
Yang,Jing;Pollock,JenniferS;Carmines,PamelaK
1型糖尿病触发肾髓厚升肢（mTAL）中蛋白激酶C （PKC）依赖的NADPH氧化酶激活，导致超氧化物生成加速。由于急性暴露于超氧化物环境会刺激mTAL的NaCl转运，我们假设糖尿病通过pkc依赖性和NADPH氧化酶依赖性机制增加了mTAL Na+转运。采用对o2敏感的氟探针测量链脲佐菌素诱导的糖尿病大鼠和假大鼠mTALs对o2的消耗。在假mTALs中，每mg蛋白的归一化相对荧光（ΔNRF）每分钟变化0.34±0.03 U，总o2消耗明显。瓦巴因（2 mmol/L）和速尿（500 μmol/L）分别减少69±4%和58±8%的o2消耗。糖尿病大鼠的总o2消耗加速（0.74±0.07 ΔNRF/min/mg蛋白；与假手术相比P<0.05），反映了瓦巴因和速尿敏感的o2消耗增加。NADPH氧化酶抑制（100 μmol/L罗布麻苷）可使糖尿病大鼠对速尿敏感的氧消耗量降至与假手术无显著差异的水平。PKC抑制剂calphostin C （1 μmol/L）或PKCα/β抑制剂Gö6976 （1 μmol/L）降低了两组对速尿敏感的o2消耗，达到的数值在假手术组和糖尿病组之间没有差异。PKCβ抑制对两组均无影响。类似的抑制模式在瓦哈因敏感的o2消耗方面也很明显。我们得出结论，在1型糖尿病期间，NADPH氧化酶和PKC（主要是PKCα）通过影响瓦他因敏感的Na+-K+- atp酶和速尿敏感的Na+-K+-2Cl -共转运体，促进了tal对o2消耗的增加，这些转运体主要负责主动转运Na+再吸收。
—Type 1 diabetes triggers protein kinase C (PKC)-dependent NADPH oxidase activation in the renal medullary thick ascending limb (mTAL), resulting in accelerated superoxide production. As acute exposure to superoxide stimulates NaCl transport by the mTAL, we hypothesized that diabetes increases mTAL Na+transport through PKC-dependent and NADPH oxidase–dependent mechanisms. An O2-sensitive fluoroprobe was used to measure O2consumption by mTALs from rats with streptozotocin-induced diabetes and sham rats. In sham mTALs, total O2consumption was evident as a 0.34±0.03 U change in normalized relative fluorescence (ΔNRF)/min per mg protein. Ouabain (2 mmol/L) reduced O2consumption by 69±4% and 500 μmol/L furosemide reduced O2consumption by 58±8%. Total O2consumption was accelerated in mTAL from diabetic rats (0.74±0.07 ΔNRF/min/mg protein;P<0.05 versus sham), reflecting increases in ouabain- and furosemide-sensitive O2consumption. NADPH oxidase inhibition (100 μmol/L apocynin) reduced furosemide-sensitive O2consumption by mTAL from diabetic rats to values not different from sham. The PKC inhibitor calphostin C (1 μmol/L) or the PKCα/β inhibitor Gö6976 (1 μmol/L) decreased furosemide-sensitive O2consumption in both groups, achieving values that did not differ between sham and diabetic. PKCβ inhibition had no effect in either group. Similar inhibitory patterns were evident with regard to ouabain-sensitive O2consumption. We conclude that NADPH oxidase and PKC (primarily PKCα) contribute to an increase in O2consumption by the mTAL during type 1 diabetes through effects on the ouabain-sensitive Na+-K+-ATPase and furosemide-sensitive Na+-K+-2Cl−cotransporter that are primarily responsible for active transport Na+reabsorption by this nephron segment.