title: The high glucose-induced stimulation of B1R and B2R expression via CB(1)R activation is involved in rat podocyte apoptosis.
abstract: OBJECTIVE
  We examined renal kallikrein-kinin system (KKS) apoptosis and its related signaling pathway in rat podocytes. In addition, we studied the relationship of cannabinoid receptor 1 (CB(1)R) with high glucose and BK receptors.
  
  
  METHODS
  Cell viability was determined by an MTT assay and apoptosis by DNA fragmentation assay, while gene expression was investigated by RT-PCR. Protein expression was analyzed by Western blot analysis. A chemical inhibitor or siRNA transfection was used to inhibit B1R, B2R, and CB(1)R signaling.
  
  
  RESULTS
  High glucose (25 mM) treatment decreased cell viability and increased DNA fragmentation. High glucose-induced DNA fragmentation and PARP and caspase-3 activations were blocked by both [des-Arg(10)]-HOE 140 (a B1R antagonist) and HOE 140 (a B2R antagonist). High glucose also increased Akt phosphorylation, ER stress-related protein expression, and NF-κB/I-κB phosphorylation in podocytes, which was blocked by both [des-Arg(10)]-HOE 140 and HOE 140. In addition, B1R and B2R siRNA transfections prevented high glucose-induced Akt and NF-κB activations in rat podocytes. Moreover, AM251 (a CB(1)R antagonist) treatment and CB(1)R siRNA transfection blocked the high glucose-induced stimulation of BK receptor expression, Akt activation, and NF-κB activation.
  
  
  CONCLUSIONS
  Our study suggests that hyperglycemia induces apoptosis via the stimulation of B1R and B2R expression through CB(1)R activation in rat podocytes in vitro, which is associated with the development of diabetic nephropathy.
authors.affiliation: Bio-therapy Human Resources Center, Department of Veterinary Physiology, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Republic of Korea.
authors.forename: Seul Ki
authors.initials: SK
authors.lastname: Lim
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Park
mesh_terms: D000818:Animals; D017209:Apoptosis; D001920:Bradykinin / Q000031:analogs & derivatives / Q000494:pharmacology; D002470:Cell Survival; D053938:DNA Fragmentation; D059865:Endoplasmic Reticulum Stress; D005786:Gene Expression Regulation; D005947:Glucose / Q000008:administration & dosage*; D006943:Hyperglycemia / Q000503:physiopathology; D016234:Kallikrein-Kinin System; D010880:Piperidines / Q000494:pharmacology; D050199:Podocytes / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D043783:Receptor, Bradykinin B1 / Q000235:genetics*; D043782:Receptor, Bradykinin B2 / Q000235:genetics*; D043884:Receptor, Cannabinoid, CB1 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D044005:Tetrahydroisoquinolines / Q000494:pharmacology
chemical_list: D010880:Piperidines; D011720:Pyrazoles; D043783:Receptor, Bradykinin B1; D043782:Receptor, Bradykinin B2; D043884:Receptor, Cannabinoid, CB1; D044005:Tetrahydroisoquinolines; C078665:HOE 140, desArg(10)-; C103505:AM 251; C065679:icatibant; D005947:Glucose; D001920:Bradykinin