title: Adenosine-induced apoptosis in glomerular mesangial cells.
abstract: BACKGROUND
  Mesangial cell apoptosis is a mechanism of resolution of glomerular hypercellularity in inflammatory forms of glomerular injury in which adenosine (ADO) was shown to play an anti-inflammatory role. This, and the observation that mesangial cell have ADO receptors prompted us to determine whether ADO induces mesangial cell apoptosis and to explore underlying mechanisms.
  
  
  METHODS
  Cultured mouse mesangial cell were incubated in the presence or absence of ADO or ADO receptor agonists (R-PIA, NECA, IB-MECA, CGS26180) or antagonists (DPCPX, DPSPX, MRS1191) for 48 hours. Cell death was assessed by trypan blue exclusion analysis. Apoptosis was assessed by DNA fragmentation, TUNEL staining and flow cytometry.
  
  
  RESULTS
  ADO and the A3 ADO receptor agonist IB-MECA induced mesangial cell death, which was markedly attenuated by the A3 receptor antagonist MRS1191. The A1 receptor agonist R-PIA, A2 receptor agonist NECA or the A2a receptor agonist CGS-12680 had no effect. The IB-MECA-induced mesangial cell death was due to apoptosis. This occurred via a cAMP independent mechanism. RT-PCR analysis revealed presence of A3, A1 and A2b but lack of A2a receptor transcripts in MC total RNA. Western blot analysis of mesangial cell lysates revealed expression the A3 receptor protein only.
  
  
  CONCLUSIONS
  The observations indicate that ADO induces mesangial cell apoptosis via stimulation of the A3 receptor.
authors.affiliation: Nephrology Division, Department of Medicine, Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903, USA.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhao
authors.forename: Toros
authors.initials: T
authors.lastname: Kapoian
authors.forename: Michelle
authors.initials: M
authors.lastname: Shepard
authors.forename: Elias A
authors.initials: EA
authors.lastname: Lianos
mesh_terms: D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis; D002452:Cell Count; D002461:Cell Line, Transformed; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1 / Q000187:drug effects / Q000235:genetics / Q000502:physiology
chemical_list: D012333:RNA, Messenger; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1; D000241:Adenosine