肾素前体激活人肾系膜细胞ERK1/2诱导TGF-β的表达

Prorenin activates ERK1 /2 and up-regulates TGF-β expression in human renal mesangial cells

目的:观察肾素前体(prorenin)能否激活体外培养的人肾系膜细胞(HRMCs)膜表面的肾素(前体)受体[(P)RR],从而活化细胞外信号调节激酶1/2(ERK1/2)信号通路。方法:体外培养HRMCs。以血管紧张素Ⅱ1型受体(AT1)阻断剂olmsartan和血管紧张素Ⅱ2型受体(AT2)阻断剂PD123319孵育细胞,再以prorenin刺激细胞,并用ERK1/2抑制剂PD98059和HRP(handle region peptide)干预。用免疫蛋白印迹方法(Western blotting)和酶标记免疫吸附测定方法(ELISA)测定目的蛋白水平,以逆转录聚合酶链反应(RT-PCR)方法测定mRNA水平。结果:Prorenin作用于体外培养的HRMCs后,在阻断AT1和AT2受体时,能激活(P)RR使ERK1/2磷酸化增强、转化生长因子(TGF-β)水平增高。这种ERK1/2信号通路的激活是(P)RR激活后效应,并可被ERK1/2信号通道阻断剂PD98059阻断。HRP不能阻断(P)RR激活所致的ERK1/2磷酸化,不能使TGF-β表达降低。结论:在体外培养的HRMCs中,prorenin能够激活(P)RR,使ERK1/2信号通道活化导致TGF-β水平增高。而HRP不能阻断(P)RR激活后ERK1/2的磷酸化及TGF-β表达的增多。

AIM： To investigate whether human prorenin can active the （ pro） renin receptor[（ P） RR]leading to the phosphorylation of extracellular regulated-kinase 1 and 2 （ ERK1 /2） and whether the putative （ P） RR blocker ＂handle-region＂peptide （ HRP） can inhibit this pathway in cultured human renal mesangial cells （ HRMCs） . METHODS： HRMCs were cultured in vitro and were pretreated with AT1 blocker olmsartan and AT2 blocker PD123319 for 30 min,then they were stimulated by prorenin,PD98059 （ inhibitor of ERK1 /2） and HRP,respectively. Phosphorylated ERK1 /2 was evaluated in Western blotting method. The concentration of transfer growth factor-β （ TGF-β） was measured using ELISA method. The mRNA of TGF-β was evaluated by RT-PCR. RESULTS： We found that prorenin induces the activation of （ P） RR in cultured HRMCs,in turn,increased the phosphorylated ERK1 /2. The protein level of TGF-β was up-regulated by the stimulation of prorenin. ERK1 /2 inhibitor PD98059 significantly decreased the phosphorylated ERK1 /2 and then down-regulated the TGF-β. HRP could inhibit neither the phosphorylation of ERK1 /2 nor the increase of TGF-β. CONCLUSION： Prorenin induces the phosphorylation of ERK1 /2 in cultured HRMCs owing to the combination to （ P） RR. The phosphorylation of ERK1 /2 leads to TGF-β increasing dramatically. It probably plays a key role in the development of kidney disease. HRP affects neither the signaling of ERK1 /2 nor the TGF-β.