Protein kinase C-dependent NAD(P)H oxidase activation induced by type 1 diabetes in renal medullary thick ascending limb.
Protein kinase C-dependent NAD(P)H oxidase activation induced by type 1 diabetes in renal medullary thick ascending limb.
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DOI：
10.1161/hypertensionaha.109.145714
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
Carmines PK
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文献类型：
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作者：
Yang J;Lane PH;Pollock JS;Carmines PK
1型糖尿病引起蛋白激酶C （PKC）依赖性超氧阴离子在肾髓质厚升肢（mTAL）的积累。我们假设这种现象与pkc依赖性NAD(P)H氧化酶激活有关。利用链脲佐菌素诱导的糖尿病大鼠和假药大鼠制备的mTAL悬浮液，对这一假设的有效性进行了探讨。糖尿病大鼠的mTAL悬液中超氧化物的产生比假手术大鼠的悬液高5倍。NAD(P)H氧化酶抑制剂apocynin使糖尿病大鼠mTALs产生的超氧化物减少80% (P<0.05)，而不改变假mTALs产生的超氧化物。糖尿病mTALs组NAD(P)H氧化酶活性比假性mTALs组高2倍以上（P<0.05）。calphostin C（广谱PKC抑制剂）或rottlerin （PKCδ抑制剂）预处理使两组NAD(P)H氧化酶活性降低~80%；然而，PKCα/β或PKCβ抑制均未改变NAD(P)H氧化酶活性。糖尿病大鼠mTALs中Nox2、Nox4和p47phox蛋白水平明显高于假手术大鼠mTALs。综上所述，糖尿病大鼠mTALs产生的超氧化物水平升高通过抑制NAD(P)H氧化酶而正常化。pkc依赖性、pkc δ依赖性和总NAD(P)H氧化酶活性在糖尿病大鼠的mTALs中比假手术大。糖尿病大鼠mTALs中Nox2、Nox4和p47phox蛋白水平升高。我们得出的结论是，糖尿病期间mTAL产生的超氧化物增加涉及pkc δ依赖的NAD(P)H氧化酶活性的增加，与酶的催化和调节亚基的蛋白质水平增加相一致。
Type 1 diabetes provokes a protein kinase C (PKC)-dependent accumulation of superoxide anion in the renal medullary thick ascending limb (mTAL). We hypothesized that this phenomenon involves PKC-dependent NAD(P)H oxidase activation. The validity of this hypothesis was explored using mTAL suspensions prepared from rats with streptozotocin-induced diabetes and from sham (vehicle-treated) rats. Superoxide production was 5-fold higher in mTAL suspensions from diabetic rats compared with suspensions from sham rats. The NAD(P)H oxidase inhibitor apocynin caused an 80% decrease in superoxide production by mTALs from diabetic rats (P<0.05 vs untreated) without altering superoxide production by sham mTALs. NAD(P)H oxidase activity was more than two-fold higher in mTALs from diabetic rats than in sham mTALs (P<0.05). Pretreatment with calphostin C (broad-spectrum PKC inhibitor) or rottlerin (PKCδ inhibitor) reduced NAD(P)H oxidase activity by ~80% in both groups; however, PKCα/β or PKCβ inhibition did not alter NAD(P)H oxidase activity in either group. Protein levels of Nox2, Nox4 and p47phox were significantly higher in diabetic mTALs than in mTALs from sham rats. In summary, elevated superoxide production by mTALs from diabetic rats was normalized by NAD(P)H oxidase inhibition. PKC-dependent, PKCδ-dependent, and total NAD(P)H oxidase activity was greater in mTALs from diabetic rats compared with sham. Protein levels of Nox2, Nox4 and p47phox were increased in mTALs from diabetic rats. We conclude that increased superoxide production by the mTAL during diabetes involves a PKCδ-dependent increase in NAD(P)H oxidase activity, in concert with increased protein levels of catalytic and regulatory subunits of the enzyme.