title: MiR-135a promotes renal fibrosis in diabetic nephropathy by regulating TRPC1.
abstract: OBJECTIVE
  The contribution of aberrantly expressed microRNAs (miRNAs) to diabetic nephropathy in vivo is poorly understood.
  
  
  METHODS
  Integrated comparative miRNA array profiling was used to examine the expression of serum miRNAs in patients with diabetic nephropathy. The abundance of miRNA-135a (miR-135a) was measured by real-time quantitative PCR in the serum and kidney tissues of patients with diabetic nephropathy. The luciferase assay combined with mutation and immunoblotting was used to screen and verify the bioinformatically predicted miRNAs. Ca(2+) entry or intracellular Ca(2+) ([Ca(2+)]i) was performed by imaging Fura-2/AM-loaded cells using a fluorescence microscopy system. The role of miR-135a in vivo was explored with locked nucleic acid antisense oligonucleotides.
  
  
  RESULTS
  MiR-135a was markedly upregulated in serum and renal tissue from patients with diabetic nephropathy, as well from db/db mice, and this was associated with the development of microalbuminuria and renal fibrosis. Furthermore, we identified transient receptor potential cation channel, subfamily C, member 1 (TRPC1) as a target of miR-135a during renal injury. We demonstrated that overexpression of TRPC1 was able to reverse the pathological effects of miR-135a on promoting proliferation of mesangial cells and increasing synthesis of extracellular matrix proteins. Moreover, miR-135a attenuated store depletion-induced Ca(2+) entry into cells by regulating TRPC1. Importantly, knockdown of miR-135a in diabetic kidneys restored levels of TRPC1 and reduced synthesis of fibronectin and collagen I in vivo. Suppressing TRPC1 levels to prevent Ca(2+) entry into cells may be a mechanism whereby miR-135a promotes renal fibrosis in diabetic kidney injury.
  
  
  CONCLUSIONS
  These findings suggest an important role for miR-135a in renal fibrosis and inhibition of miR-135a might be an effective therapy for diabetic nephropathy.
authors.affiliation: Department of Nephrology, The First Affiliated Hospital, Sun Yat-Sen University, 58th, Zhongshan Road II, 510080, Guangzhou, People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.forename: Fenfen
authors.initials: F
authors.lastname: Peng
authors.forename: Xi
authors.initials: X
authors.lastname: Xia
authors.forename: Chen
authors.initials: C
authors.lastname: Zhao
authors.forename: Qimei
authors.initials: Q
authors.lastname: Luo
authors.forename: Weiming
authors.initials: W
authors.lastname: Guan
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Li
authors.forename: Xueqing
authors.initials: X
authors.lastname: Yu
authors.forename: Fengxian
authors.initials: F
authors.lastname: Huang
mesh_terms: D000818:Animals; D002460:Cell Line; D003928:Diabetic Nephropathies / Q000378:metabolism* / Q000473:pathology; D005355:Fibrosis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007668:Kidney / Q000473:pathology*; D050527:Mesangial Cells / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D035683:MicroRNAs / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C544965:MIRN135 microRNA, human; D035683:MicroRNAs; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1