The cyclin kinase inhibitor p21WAF1/CIP1 is required for glomerular hypertrophy in experimental diabetic nephropathy
The cyclin kinase inhibitor p21WAF1/CIP1 is required for glomerular hypertrophy in experimental diabetic nephropathy
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DOI：
10.1046/j.1523-1755.1999.00728.x
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发表时间：
1999-11-01
影响因子：
19.6
通讯作者：
Shankland, SJ
中科院分区：
文献类型：
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作者：
Al-Douahji, M;Brugarolas, J;Shankland, SJ
背景。糖尿病肾病的特征是肾小球肥大。我们最近发现，实验性糖尿病与细胞周期蛋白激酶抑制剂 p21(WAF1/CIP1) (p21) 的肾小球表达增加有关。此外，体外葡萄糖诱导的肾小球系膜细胞肥大也与 p21 表达上调有关。在这项研究中。我们在体内测试了 p21 介导糖尿病肾小球肥大的假设。方法。链脲佐菌素在 p21 基因缺失小鼠 (p21 -/-) 和野生型小鼠 (p21 +/+) 中诱导实验性糖尿病。第 60 天时，从糖尿病小鼠和对照（注射柠檬酸盐）p21 +/+ 和 p21 -/- 小鼠中获取肾活检。该组织用于肾小球大小（通过计算机图像分析系统测量）、肾小球细胞结构（细胞计数）、肾小球基质扩张（银染）、细胞凋亡（TUNEL）和转化生长因子-Pi 表达的形态学研究 (TGF-PI)通过原位杂交。结果。与对照组相比，第60天糖尿病p21+/+小鼠的肾小球簇面积增加了11.21%（3329.98+/-244.05μm(2) vs. 2994.39+/-176.22μm(2)，P=0.03），并且与对照组相比，第60天糖尿病p21+/+小鼠的肾小球细胞计数没有变化。这些发现与肾小球肥大一致。相反，与对照组相比，第60天时糖尿病p21 -/- 小鼠的肾小球簇面积没有增加（3544.15 +/- 826.49 vs. 3449.15 +/- 109.65，P = 0.82），肾小球细胞计数也没有增加（41.41 +/- 13.18 vs. 46.95 +/-） 3.00，P = 0.43）。与对照组相比，糖尿病 p21 +/+ 小鼠（而非 p21 -/- 小鼠）在第 60 天出现蛋白尿增加。通过增殖细胞核抗原免疫染色测量，与对照组相比，糖尿病 p21 +/+（2.1 倍）和 p21 -/-（7.61 倍）小鼠的肾小管细胞增殖增加。糖尿病小鼠的肾小球细胞凋亡没有增加。尽管两种糖尿病小鼠品系的肾小球 TGF-β(1) mRNA 水平在第 60 天时均有所增加，但肾小球基质并未扩张。
Background. Diabetic nephropathy is characterized by glomerular hypertrophy. We have recently shown that experimental diabetes mellitus is associated with an increase in glomerular expression of the cyclin kinase inhibitor p21(WAF1/CIP1) (p21) Furthermore, in vitro glucose-induced mesangial cell hypertrophy is also associated with an up-regulated expression of p21. In this study. we tested the hypothesis that p21 mediates diabetic glomerular hypertrophy in vivo.Methods. Experimental diabetes mellitus was induced by streptozotocin in mice in which p21 was genetically deleted (p21 -/-) and in wild-type mice (p21 +/+). Kidney biopsies were obtained from diabetic and control (citrate injected) p21 +/+ and p21 -/- mice at day 60. The tissue was used for morphologic studies of glomerular size (measured by computer image-analysis system), glomerular cellularity (cell count), glomerular matrix expansion (silver stain), apoptosis (TUNEL), and expression of transforming growth factor-Pi (TGF-PI) by in situ hybridization.Results. The glomerular tuft area increased 11.21% in diabetic p21 +/+ mice at day 60 compared with control (3329.98 +/- 244.05 mu m(2) vs. 2994.39 +/- 176.22 mu m(2), P = 0.03), and the glomerular cell count did not change in diabetic p21 +/+ mice at day 60 compared with the control. These findings are consistent with glomerular hypertrophy. In contrast, the glomerular tuft area did not increase in diabetic p21 -/- mice at day 60 compared with the control (3544.15 +/- 826.49 vs. 3449.15 +/- 109.65, P = 0.82), nor was there an increase in glomerular cell count (41.41 +/- 13.18 vs. 46.95 +/- 3.00, P = 0.43). Diabetic p21 +/+ mice, but not p21 -/- mice, developed an increase in proteinuria at day 60 compared with the control. Tubular cell proliferation, measured by proliferating cell nuclear antigen immunostaining, was increased in both diabetic p21 +/+ (2.1-fold) and p21 -/- (7.61-fold) mice compared with controls. Glomerular cell apoptosis did not increase in diabetic mice. Although glomerular TGF-beta(1), mRNA levels increased in both strains of diabetic mice at day 60, the glomerular matrix did not expand.