Adenosine-induced apoptosis in glomerular mesangial cells

Area of Science:

• Nephrology
• Cell Biology
• Pharmacology

Background:

• Mesangial cell apoptosis resolves glomerular hypercellularity in inflammatory kidney injury.
• Adenosine (ADO) exhibits anti-inflammatory properties in glomerular diseases.
• Mesangial cells possess adenosine receptors, suggesting a role for ADO in cell fate.

Purpose of the Study:

• To investigate whether adenosine induces apoptosis in mesangial cells.
• To elucidate the underlying molecular mechanisms of adenosine-induced mesangial cell apoptosis.
• To identify the specific adenosine receptor subtypes involved.

Main Methods:

• Cultured mouse mesangial cells were treated with adenosine or its receptor agonists/antagonists.
• Cell viability was assessed using trypan blue exclusion.
• Apoptosis was quantified via DNA fragmentation, TUNEL staining, and flow cytometry.
• Adenosine receptor expression was analyzed using RT-PCR and Western blotting.

Main Results:

• Adenosine and the A3 receptor agonist IB-MECA induced significant mesangial cell death.
• This cell death was primarily apoptosis and was blocked by the A3 receptor antagonist MRS1191.
• A1, A2, and A2a receptor agonists did not induce apoptosis.
• Mesangial cells expressed A3, A1, and A2b receptor transcripts, but only A3 receptor protein was detected.
• The apoptotic pathway was independent of cyclic AMP (cAMP).

Conclusions:

• Adenosine induces mesangial cell apoptosis predominantly through the activation of the A3 receptor.
• This mechanism is crucial for the resolution of glomerular hypercellularity.
• The findings highlight the A3 adenosine receptor as a potential therapeutic target in inflammatory glomerular diseases.