Département de medecine, Université de Montréal, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montréal, QC, H2X 0A9, Canada.
Département de pathologie et biologie cellulaire, Université de Montréal, Centre de recherche, Hôpital Maisonneuve-Rosemont, 5415 boul. de l'Assomption, Montréal, QC, H1T 2M4, Canada.
Sci Rep. 2019 Apr 30;9(1):6687. doi: 10.1038/s41598-019-43218-2.
We investigated the molecular mechanism(s) by which insulin prevents Bcl2-modifying factor (Bmf)-induced renal proximal tubular cell (RPTC) apoptosis and loss in diabetic mice. Transgenic mice (Tg) mice specifically overexpressing human BMF in RPTCs and non-Tg littermates were studied at 10 to 20 weeks of age. Non-diabetic littermates, diabetic Akita mice +/- insulin implant, Akita Tg mice specifically overexpressing heterogeneous nuclear ribonucleoprotein F (hnRNP F) in their RPTCs and immortalized rat renal proximal tubular cells (IRPTCs) were also studied. BMF-Tg mice exhibited higher systolic blood pressure, urinary albumin/creatinine ratio, RPTC apoptosis and urinary RPTCs than non-Tg mice. Insulin treatment in Akita mice and Akita mice overexpressing hnRNP F suppressed Bmf expression and RPTC apoptosis. In hyperinsulinemic-euglycemic wild type mice, renal Bmf expression was down-regulated with up-regulation of hnRNP F. In vitro, insulin inhibited high glucose-stimulation of Bmf expression, predominantly via p44/42 mitogen-activated protein kinase (MAPK) signaling. Transfection of p44/42 MAPK or hnRNP F small interfering RNA (siRNA) prevented insulin inhibition of Bmf expression. HnRNP F inhibited Bmf transcription via hnRNP F-responsive element in the Bmf promoter. Our results demonstrate that hnRNP F suppression of Bmf transcription is an important mechanism by which insulin protects RPTCs from apoptosis in diabetes.
我们研究了胰岛素防止 Bcl2 修饰因子 (Bmf) 诱导的糖尿病小鼠肾近端管状细胞 (RPTC) 凋亡和丢失的分子机制。在 10 至 20 周龄时，研究了特异性在 RPTC 中过表达人 Bmf 的转基因 (Tg) 小鼠和非 Tg 同窝仔鼠。还研究了非糖尿病同窝仔鼠、糖尿病 Akita 小鼠 +/-胰岛素植入物、特异性在其 RPTC 中过表达异质核核糖核蛋白 F (hnRNP F) 的 Akita Tg 小鼠和永生化大鼠肾近端管状细胞 (IRPTCs)。与非 Tg 小鼠相比，BMF-Tg 小鼠表现出更高的收缩压、尿白蛋白/肌酐比值、RPTC 凋亡和尿 RPTCs。胰岛素治疗 Akita 小鼠和过表达 hnRNP F 的 Akita 小鼠抑制了 Bmf 表达和 RPTC 凋亡。在高胰岛素血症正常血糖的野生型小鼠中，随着 hnRNP F 的上调，肾脏 Bmf 表达下调。在体外，胰岛素抑制高葡萄糖刺激的 Bmf 表达，主要通过 p44/42 丝裂原活化蛋白激酶 (MAPK) 信号传导。转染 p44/42 MAPK 或 hnRNP F 小干扰 RNA (siRNA) 可防止胰岛素抑制 Bmf 表达。hnRNP F 通过 Bmf 启动子中的 hnRNP F 反应元件抑制 Bmf 转录。我们的结果表明，hnRNP F 抑制 Bmf 转录是胰岛素在糖尿病中保护 RPTC 免于凋亡的重要机制。
