Ouyang Xiaosen, Le Thu H, Roncal Carlos, Gersch Christine, Herrera-Acosta Jaime, Rodriguez-Iturbe Bernardo, Coffman Thomas M, Johnson Richard J, Mu Wei
Division of Nephrology, Dept. of Medicine, Univ. of Florida, Gainesville, FL 32610, USA.
Am J Physiol Renal Physiol. 2005 Oct;289(4):F902-10. doi: 10.1152/ajprenal.00141.2005. Epub 2005 May 31.
AT(1) double receptor (AT(1A) and AT(1B)) knockout mice have lower blood pressure, impaired growth, and develop early renal microvascular disease and tubulointerstitial injury. We hypothesized that there would be an increased expression of vasoactive, profibrotic, and inflammatory mediators expressed in the kidneys of AT(1) double-knockout mice. We examined the renal expression of various mediator systems in control (n = 6) vs. double-knockout mice (n = 6) at 3-5 mo of age by real-time PCR, immunohistochemistry, and Western blot analysis. AT(1) double-knockout mice show activation of Th1-dependent pathways (with increased expression of IFN-alpha, IL-2 mRNA) with increased expression of both monocyte (MCP-1 mRNA) and T cell (RANTES mRNA) chemokines, infiltration of CD4(+) and CD11b(+) cells, increased fibrosis-associated mediators (CTGF, TGF-beta and TNF-alpha mRNA) and extracellular matrix (collagens I and III mRNA and protein) deposition compared with controls (P < 0.05 for all markers). These changes were associated with increased mRNA expression of endothelin (ET)-1 and ET-A receptor (P < 0.05), cyclooxygenase (COX)-2/TXA2 synthase (P < 0.05), NADPH oxidase (p40-phox, p67-phox, P < 0.05) and iNOS and nNOS (P < 0.05). COX-2 and nNOS protein were also increased in the kidneys of AT(1) double-knockout mice by Western blot analysis (P < 0.05). Although renin and angiotensinogen mRNA expression were increased in the knockout mice, AT(2) receptor mRNA expression was not significantly different from wild-type mice. In conclusion, the absence of the AT(1) receptor is associated with marked renal alterations in vasoactive, profibrotic, and immune mediators with an inflammatory pattern favoring a Th1 phenotype.
血管紧张素Ⅱ 1型双受体（AT(1A) 和AT(1B)）基因敲除小鼠血压较低、生长发育受损，并较早出现肾微血管疾病和肾小管间质损伤。我们推测，血管紧张素Ⅱ 1型双基因敲除小鼠肾脏中血管活性、促纤维化和炎症介质的表达会增加。我们通过实时聚合酶链反应、免疫组织化学和蛋白质印迹分析，检测了3至5月龄对照小鼠（n = 6）和双基因敲除小鼠（n = 6）各种介质系统的肾脏表达情况。血管紧张素Ⅱ 1型双基因敲除小鼠表现出Th1依赖途径的激活（干扰素-α、白细胞介素-2信使核糖核酸表达增加），单核细胞趋化因子（单核细胞趋化蛋白-1信使核糖核酸）和T细胞趋化因子（调节激活正常T细胞表达和分泌因子信使核糖核酸）表达均增加，CD4(+) 和CD11b(+) 细胞浸润，与对照组相比，纤维化相关介质（结缔组织生长因子、转化生长因子-β和肿瘤坏死因子-α信使核糖核酸）和细胞外基质（Ⅰ型和Ⅲ型胶原信使核糖核酸及蛋白质）沉积增加（所有标志物P < 0.05）。这些变化与内皮素（ET）-1和ET-A受体信使核糖核酸表达增加（P < 0.05）、环氧化酶（COX）-2/TXA2合酶（P < 0.05）、烟酰胺腺嘌呤二核苷酸磷酸氧化酶（p40-吞噬细胞氧化酶、p67-吞噬细胞氧化酶，P < 0.05）以及诱导型一氧化氮合酶和神经元型一氧化氮合酶（P < 0.05）信使核糖核酸表达增加有关。蛋白质印迹分析显示，血管紧张素Ⅱ 1型双基因敲除小鼠肾脏中COX-2和神经元型一氧化氮合酶蛋白也增加（P < 0.05）。虽然敲除小鼠中肾素和血管紧张素原信使核糖核酸表达增加，但血管紧张素Ⅱ 2型受体信使核糖核酸表达与野生型小鼠无显著差异。总之，血管紧张素Ⅱ 1型受体缺失与血管活性、促纤维化和免疫介质的明显肾脏改变有关，呈现出有利于Th1表型的炎症模式。
