细胞外信号调节蛋白激酶介导醛固酮诱导的肾小球系膜细胞增殖

Role of extracellular signal-regulated kinases in aldosterone-induced rat mesangial cellsproliferation

目的探讨细胞外信号调节蛋白激酶（ERKl／2）在醛固酮诱导肾小球系膜细胞（RMC）增殖中的作用。方法获取6～8周健康雄性SD大鼠RMC并鉴定，取第5～10代的细胞用于实验。细胞分为6组：对照组；PD98059（10μmol／L）组；依普利酮（1μmol／L）组；醛固酮（100nmol／L）组；醛固酮（100nmol／L）＋PD98059（10μmol／L）组；醛固酮（100nmol／L）＋依普利酮（1μmol／L）组。采用Western印迹技术检测sD大鼠RMC盐皮质激素受体（MR）表达状况，以及醛固酮刺激后RMCERKl／2活性状态。采用，H一胸腺嘧啶核苷（3^H—TdR）掺入法检测RMC增殖状况。结果体外培养的SD大鼠RMC有MR蛋白表达。醛固酮（100nmol／L）刺激RMC10rain使ERKl／2活性显著增高（P〈0．05）；刺激30h时使RMC的。H—TdR掺入量显著增加[（1．35±0．08）倍，P〈0．051。选择性醛固酮受体拮抗剂依普利酮（1μmol／L）及MAPK—ERK激酶（MEK）特异性抑制剂PD98059（10μmol／L）可阻止醛固酮诱导的RMCERKl／2激活以及。H—TdR掺人量增加。结论醛固酮通过激活ERKl／2信号转导通路诱导RMC增殖。

Objective To determine the role of extracellular signal-regulated kinases （ERKl/2） in aldosterone-induced rat mesangial cells （RMCs） proliferation. Methods RMCs were obtained from intact glomeruli of 4- to 6-week-old Sprague-Dawley rats and characterized according to published methods. RMCs between passages 5 and passages 10 were used. Protein levels of mineralocorticoid receptor （MR） in RMCs were analyzed by Western blotting. The cells were divided into the following groups： control group, PD98059 （10 μmol/L） group, eplerenone （1 μml/L） group, aldosterone （100 nmol/L） group, aldosterone （100 nmol/L） ＋PD98059 （10 μ mol/L） group, aldosteroue （100 nmol/L）＋eplerenone （1 μmol/L） group. ERK1/2 activity was measured by Western blotting. Cell proliferation of RMCs was evaluated by [3^H]-thymidine uptake measurements. Results MR protein expression in RMCs was confirmed by Western blotting. Aldosterone activated ERK1/2, and the maximal ERK1/2 activation induced by aldosterone was at a concentration of 100 nmol/L. Aldosterone （100 nmol/L）-induced activation of ERK1/2 peaked at 10 minutes （P〈0.05）. Pretreatment with a selective MR antagonist eplerenone （1 p^mol/L） significantly attenuated aldosterone-induced ERK1/2 phospholylation. Aldosterone （100 nmol/L） treatment for 30 hours increased [^3H]-thymidine incorporation of RMCs （135%±8% of controls, P〈0.05）. Cellular proliferation induced by aldosterone could be prevented by pretreatment with eplerenone or an ERK（MEK） inhibitor PD988059. Conclusion Aldosterone induces RMCs proliferation through MR and ERK1/2 activation, which may contribute to the pathogenesis of glomerular mesangial injury.