Chen Da-Peng, Ma Ye-Ping, Zhuo Li, Zhang Zheng, Zou Gu-Ming, Yang Yue, Gao Hong-Mei, Li Wen-Ge
Graduate School of Peking Union Medical College, Beijing 100730, China.
Department of Nephrology, China-Japan Friendship Hospital, Beijing 100029, China.
Oncotarget. 2017 Dec 9;9(1):418-427. doi: 10.18632/oncotarget.23063. eCollection 2018 Jan 2.
1,25-Dihydroxyvitamin D(1,25(OH) D) is a secosteroid with antiproliferative property. It also plays a pivotal renoprotective role in diabetic nephropathy. We investigated whether 1,25(OH)D could inhibit the proliferation of rat mesangial cells exposed to high glucose via the DNA-damage-inducible transcript 4/mammalian target of rapamycin(DDIT4/mTOR) pathway. The cell proliferation rate and cell cycle duration were measured using cell counting kit-8 assay and flow cytometry. Protein expression was assayed by Western blot. Glucose acted as a growth factor in rat mesangial cells, promoted cell proliferation. In parallel, the protein expression of DDIT4, TSC1/TSC2, and 4E-BP1 were decreased, and Rheb, mTOR, and p70S6K were increased. Acting via the DDIT4/mTOR signaling, 1,25(OH) D treatment reversed these pathological changes, upregulated DDIT4, TSC1/TSC2, and 4E-BP1, downregulated Rheb, mTOR, and p70S6K. The short-term overexpression of DDIT4 inhibited the proliferation of rat mesangial cells, similar to 1,25(OH) D treatment. siRNA knockdown of DDIT4 suppressed antiproliferative responses to 1,25(OH) D. These results suggest that 1,25(OH) D inhibits the proliferation of rat mesangial cells induced by high glucose via the DDIT4/mTOR signaling pathway.
1,25-二羟基维生素D（1,25(OH)D）是一种具有抗增殖特性的甾体类化合物。它在糖尿病肾病中也发挥着关键的肾脏保护作用。我们研究了1,25(OH)D是否能通过DNA损伤诱导转录本4/哺乳动物雷帕霉素靶蛋白（DDIT4/mTOR）途径抑制暴露于高糖环境下的大鼠系膜细胞的增殖。使用细胞计数试剂盒-8法和流式细胞术测量细胞增殖率和细胞周期持续时间。通过蛋白质印迹法检测蛋白质表达。葡萄糖在大鼠系膜细胞中充当生长因子，促进细胞增殖。同时，DDIT4、结节性硬化复合物1/2（TSC1/TSC2）和真核细胞起始因子4E结合蛋白1（4E-BP1）的蛋白质表达降低，而小G蛋白Rheb、mTOR和p70核糖体蛋白S6激酶（p70S6K）的表达增加。通过DDIT4/mTOR信号传导，1,25(OH)D处理逆转了这些病理变化，上调了DDIT4、TSC1/TSC2和4E-BP1，下调了Rheb、mTOR和p70S6K。DDIT4的短期过表达抑制了大鼠系膜细胞的增殖，类似于1,25(OH)D处理。DDIT4的小干扰RNA（siRNA）敲低抑制了对1,25(OH)D的抗增殖反应。这些结果表明，1,25(OH)D通过DDIT4/mTOR信号通路抑制高糖诱导的大鼠系膜细胞增殖。
