title: Ruboxistaurin attenuates diabetic nephropathy via modulation of TGF-β1/Smad and GRAP pathways.
abstract: OBJECTIVE
  To investigate whether ruboxistaurin (a selective PKC-β inhibitor) mediates renoprotective effect via interference with TGF-β1/Smad-GRAP cross-signalling.
  
  
  METHODS
  Diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (55 mg/kg). Then, the diabetic rats were treated with ruboxistaurin (10 mg/kg, p.o) for 6 weeks. Valsartan (15 mg/kg, p.o) was used as a positive control. After 6 weeks of treatment, diabetic nephropathy biomarkers were assessed. TGF-β1, Smad2, and Smad3 mRNA and protein levels were detected using qPCR and western blot analysis.
  
  
  RESULTS
  Data showed that serum creatinine, kidney/body weight ratio and urinary albumin excretion significantly increased in diabetic rats. These changes were significantly attenuated by treatment with ruboxistaurin. A significant up-regulation of TGF-β1, Smad2 and Smad3 mRNA expression was observed in diabetic rats, which was alleviated by administration of ruboxistaurin. Furthermore, immunoblotting showed a significant improvement in protein levels of TGF-β1 (P < 0.01), Smad2/3 (P < 0.01) and p-Smad3 (P < 0.001) in diabetic rats treated with ruboxistaurin compared to untreated. Importantly, the reduction in GRAP protein expression in diabetic kidney was prevented by treatment with ruboxistaurin.
  
  
  CONCLUSIONS
  These data suggest that the renoprotective effect of ruboxistaurin is possibly due to down-regulation of TGF-β1/Smad pathway and normalization of GRAP protein expression.
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Asma S
authors.initials: AS
authors.lastname: Al-Onazi
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Nouf M
authors.initials: NM
authors.lastname: Al-Rasheed
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.|Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
authors.forename: Hala A
authors.initials: HA
authors.lastname: Attia
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Nawal M
authors.initials: NM
authors.lastname: Al-Rasheed
authors.affiliation: Department of Anatomy, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Raeesa M
authors.initials: RM
authors.lastname: Ahmed
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Maha A
authors.initials: MA
authors.lastname: Al-Amin
authors.affiliation: Cardiovascular Research Program, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.
authors.forename: Coralie
authors.initials: C
authors.lastname: Poizat
mesh_terms: D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000150:complications / Q000188:drug therapy; D003928:Diabetic Nephropathies / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D051380:GRB2 Adaptor Protein / Q000378:metabolism*; D007211:Indoles / Q000008:administration & dosage / Q000627:therapeutic use*; D007677:Kidney Function Tests; D008297:Male; D008301:Maleimides / Q000008:administration & dosage / Q000627:therapeutic use*; D064546:Protein Kinase C beta / Q000037:antagonists & inhibitors*; D017208:Rats, Wistar; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism*; D051900:Smad3 Protein / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
chemical_list: D051380:GRB2 Adaptor Protein; C495950:Grb2 protein, rat; D007211:Indoles; D008301:Maleimides; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D051900:Smad3 Protein; C497787:Smad3 protein, rat; D053773:Transforming Growth Factor beta1; C099154:ruboxistaurin; D064546:Protein Kinase C beta
keywords: GRAP; TGF-β1; diabetic nephropathy; ruboxistaurin; smad