Suppression of the development of diabetic nephropathy by expression of non-smooth muscle calponin

碱性钙蛋白(calponin-H1)是一种平滑肌分化特异性基因，可能改善肾小球对损伤的反应。相反，没有证据表明钙离子-H2亚型对肾脏疾病的影响。中性钙蛋白(Calponin-H2，CN2)是一种非平滑肌亚型，可能在细胞骨架组织中发挥生理作用。CN2还能有效地抑制平滑肌细胞的迁移。我们推测CN2参与了糖尿病间质损伤的过程。我们用Cre-loxP定点重组系统建立了CN2转基因小鼠(CN2-TG)，仅在硫酸镉(0.5 mg/kg体重/天)处理时才诱导CN2的表达。用链佐菌素(STZ，100 mg/kg体重×2次/3d)诱导CN2-TG小鼠和野生型(WT)小鼠糖尿病模型。在第一次注射链脲佐菌素前5天开始腹腔注射硫酸镉。分别于发病后第8天、第30天和第0天(n=6 I…)行肾切除术每个n个以上)。免疫组织化学染色检测增殖细胞(Ki-67)、巨噬细胞(F4/80)和间质细胞表型变化(α-平滑肌肌动蛋白，ASMA)以评价小鼠的间质炎症反应。CN2-TG在第8天显著抑制间质细胞增殖(Ki-67+细胞/高倍视野，HPF)(3.7±0.5(m±SE)，WT 5.7±0.4，p&lt；0.05)，但在第30天无明显抑制(1.1±0.4vs1.2±0.2)。CN2-TG在第8天(3.7±0.1vs6.9±1.3，p&lt；0.02)和第30天(2.2±0.7vs5.4±0.5，p&lt；0.01)诱导巨噬细胞在间质中募集的巨噬细胞减少(F4/80^+细胞/hpf)。两组间ASMA表达和血压(包括收缩压和舒张压)均无显著差异。因此，在糖尿病早期，CN2的过表达抑制了间质细胞的增殖和巨噬细胞的浸润。综上所述，CN2先前的抗炎特性可能在糖尿病间质肾损害的后续发展中起关键作用。较少

Basic calponin (calponin-h1), smooth muscle differentiation-specific gene, may improve the glomerular response to injury. To the contrary, there was no evidence about calponion-h2 isoform, on the effect of kidney disease. Neutral calponin (Calponin-h2, CN2) is a non-smooth muscle isoform, and a may play a physiological role in cytoskeletal organization. CN2 also powerfully suppresses smooth muscle cell migration. We hypothesized that CN2 is involved in the course of diabetic interstitial injury. We established CN2 transgenic (CN2-Tg) mouse with the CRE-loxP site-specific recombination system, in that CN2 expression is induced only during the treatment of cadmium sulfate (0.5mg/kg BW/day). Diabetes was induced by streptozocin (STZ, 100mg/kg BW x 2 times/3days) on both of CN2-Tg mouse and wild type ones (WT). Cadmium sulfate intraperitoneal treatment was started 5 days before the first STZ injection. Nephrectomy was done on 8 and 30 days after disease induction as well as on day 0 (n=6 i … More n each). Immunostaining for proliferating cells (ki-67), macrophages (F4/80) and phenotypic change of interstitial cells (a-smooth muscle actin, aSMA) for evaluation of interstitial inflammation on all mice and all data were evaluated by computer-analysis system.The interstitial cell proliferation (ki-67^+ cells/high power field, hpf) was significantly suppressed in CN2-Tg at day 8 (3.7±0.5 (m±SE) in CN2-Tg, vs 5.7±0.4 in WT, p<0.05), but not at day 30 (1.1±0.4 vs 1.2±0.2). Reduction of macrophages recruitment in the interstitium (F4/80^+ cells/hpf) was induced in CN2-Tg at day 8 (3.7±0.1 vs 6.9±1.3, p<0.02), and day 30 (2.2±0.7 vs 5.4±0.5, p<0.01). There was no significant difference in both of aSMA expression and blood pressure (both systolic and diastolic) between two groups. Thus, CN2 overexpression suppressed both of interstitial cell proliferation and macrophages infiltration from early phase in diabetes mellitus.In conclusion, precedent anti-inflammatory property of CN2 may be critical for subsequebt development of interstitial renal injuriy in diabetes mellitus. Less