Indoxyl sulfate stimulates proliferation of rat vascular smooth muscle cells
Indoxyl sulfate stimulates proliferation of rat vascular smooth muscle cells
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DOI：
10.1038/sj.ki.5000340
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发表时间：
2006-05-01
影响因子：
19.6
通讯作者：
Kusano, E.
中科院分区：
文献类型：
--
作者：
Yamamoto, H.;Tsuruoka, S.;Kusano, E.
血管平滑肌细胞(VSMC)增殖是动脉硬化进展过程中的一个重要事件。临床研究表明，尿毒症毒素可加重肾功能衰竭患者的动脉硬化。吲哚硫酸盐(IS)是一种蛋白结合性较强的尿毒症毒素，但其对VSMC增殖的影响尚未见报道。采用细胞计数试剂盒(4-[3-[4-洛多苯基]-2-4(4-硝基苯基)-2H-5-四氮杂-1，3-苯二磺酸]法)和[(3)H]胸腺嘧啶核苷掺入法检测IS对大鼠VSMC增殖的影响。我们进一步评估了丝裂原活化蛋白激酶(MAPK；p44/42MAPK)在IS诱导的VSMC增殖中的作用。用抗大鼠有机阴离子转运体(OAT)3抗体对VSMCs进行免疫组织化学染色。实时定量聚合酶链式反应检测血小板衍生生长因子(PDGF)-A链、-C链及PDGF-β受体的mRNA表达。以浓度依赖的方式刺激VSMCs增殖，并激活p44/42MAPK。刺激大鼠VSMC增殖所需的IS浓度约为250 mU M，与终末期肾功能衰竭患者血清中的浓度相容。PD98059(10 MU M)是MAPK/细胞外信号调节激酶的选择性抑制剂，可抑制IS诱导的(250 MU M)VSMC增殖和MAPK的磷酸化。OAT的抑制剂和底物丙磺舒(0.5 mM)可抑制IS诱导的VSMC(250mM)增殖。在VSMC中检测到大鼠OAT3。IS可显著增加PDGF-C链和PDGF-β受体的mRNA表达。结论：IS在体外可直接刺激大鼠VSMC增殖并激活MAPK。这可能是终末期肾病患者动脉粥样硬化病变进展的机制之一。
Vascular smooth muscle cell ( VSMC) proliferation is a key event in the progression of arteriosclerosis. Clinical studies show that uremic toxins deteriorate the arteriosclerosis in renal failure patients. Indoxyl sulfate ( IS) is a strong protein-bound uremic toxin, but the effect of IS on VSMC proliferation has not been studied. We examined the effect of IS on rat VSMC proliferation, assessed by a cell counting kit ( 4-[ 3-[4-lodophenyl]-2-4( 4-nitrophenyl)-2H-5-tetrazolio-1, 3-benzene disulfonate] assay) and by [ (3) H] thymidine incorporation in vitro. We further evaluated a contribution of mitogen-activated protein kinase ( MAPK; p44/42 MAPK) to VSMC proliferation by IS. Immunohistochemical staining was performed for VSMCs using antirat organic anion transporter ( OAT) 3 antibody. The mRNA expressions of platelet-derived growth factor ( PDGF)-A and -C chains, and PDGF-beta receptor were evaluated by real-time PCR. IS stimulated the proliferation of VSMCs in a concentration-dependent manner and activated p44/42 MAPK. Concentration of IS needed to stimulate the proliferation of rat VSMC was about 250 mu M, which is compatible with that in the serum of end-stage renal failure patients. PD98059 ( 10 mu M), a selective inhibitor of MAPK/extracellular signal-regulated kinase, inhibited the IS-induced ( 250 mu M) VSMC proliferation and phosphorylation of MAPK. Probenecid ( 0.5 mM), an inhibitor and substrate of OAT, inhibited the IS-induced ( 250 mu M) VSMC proliferation. Rat OAT3 was detected in VSMCs. The mRNA expressions of PDGF-C chain and PDGF-beta receptor were significantly increased by IS. We conclude that IS directly stimulates rat VSMC proliferation and activates MAPK in vitro. This might be one of the mechanisms underlying the progression of atherosclerotic lesions in end-stage renal disease patients.