Adenosine-induced apoptosis in glomerular mesangial cells.
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.
Zhao
Zhihui
Z
Nephrology Division, Department of Medicine, Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903, USA.
Kapoian
Toros
T
Shepard
Michelle
M
Lianos
Elias A
EA
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
D012333:RNA, Messenger; D043684:Receptor, Adenosine A3; D018047:Receptors, Purinergic P1; D000241:Adenosine