title: MicroRNA-195 promotes apoptosis in mouse podocytes via enhanced caspase activity driven by BCL2 insufficiency.
abstract: BACKGROUND
  The apoptosis of podocytes is a characteristic event in diabetic nephropathy. The aim of this study was to investigate whether microRNAs (miRNAs) affect podocyte apoptosis in diabetic circumstances.
  
  
  METHODS
  Diabetic nephropathy was induced in DBA/2 mice by intraperitoneal injections of streptozotocin, and the levels of proteinuria were measured with ELISA. Apoptosis-related miRNAs were screened in isolated glomeruli. A conditionally immortalized mouse podocyte cell line was cultured in 25 mMD-glucose and either transfected with miRNA-195 (miR-195) mimics or inhibitors. The levels of BCL2 and caspase expression were determined using real-time RT-PCR and Western blot analysis, respectively. We also measured WT-1 and synaptopodin in podocytes. Apoptosis of podocytes was assessed with Hoechst 33258 nuclear staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and flow cytometry.
  
  
  RESULTS
  The expression of miR-195 was elevated in both diabetic mice with proteinuria and podocytes that were cultured in high glucose. Transfection with miR-195 reduced the protein levels of BCL2 and contributed to podocyte apoptosis via an increase in caspase-3. miR-195-treated podocytes underwent actin rearrangement and failed to synthesize sufficient levels of WT-1 and synaptopodin proteins, which suggests that the cells had suffered injuries similar to those observed in diabetic nephropathy in both humans and animal models.
  
  
  CONCLUSIONS
  Taken together, our findings demonstrate that miR-195 promotes apoptosis of podocytes under high-glucose conditions via enhanced caspase cascades for BCL2 insufficiency. This work thus presents a meaningful approach for deciphering mechanisms, by which miRNAs participate in diabetic renal injury.
authors: Department of Nephrology and Rheumatology, Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, China.
authors: Yu-Qiang
authors: YQ
authors: Chen
authors: Xiao-Xia
authors: XX
authors: Wang
authors: Xing-Mei
authors: XM
authors: Yao
authors: Dong-Liang
authors: DL
authors: Zhang
authors: Xu-Feng
authors: XF
authors: Yang
authors: Shou-Fu
authors: SF
authors: Tian
authors: Nian-Song
authors: NS
authors: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D001713:Biphenyl Compounds / Q000494:pharmacology; D006690:Bisbenzimidazole / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism*; D005434:Flow Cytometry / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D020287:In Situ Nick-End Labeling; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D035683:MicroRNAs / Q000378:metabolism*; D008969:Molecular Sequence Data; D009596:Nitrophenols / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D050199:Podocytes / Q000166:cytology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012689:Sequence Homology, Nucleic Acid; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: C501332:ABT-737; D001713:Biphenyl Compounds; C569389:MIRN195a microRNA, mouse; D035683:MicroRNAs; D009596:Nitrophenols; D010879:Piperazines; D019253:Proto-Oncogene Proteins c-bcl-2; D013449:Sulfonamides; D020169:Caspases; D006690:Bisbenzimidazole