Normalization of A2A and A3 adenosine receptor up-regulation in rheumatoid arthritis patients by treatment with anti-tumor necrosis factor alpha but not methotrexate.
OBJECTIVE
To investigate A(1), A(2A), A(2B), and A(3) adenosine receptors in lymphocytes and neutrophils from patients with early rheumatoid arthritis (ERA) as well as from RA patients treated with methotrexate (MTX) or anti-tumor necrosis factor alpha (anti-TNFalpha), as compared with those in age-matched healthy controls, and to examine correlations between the status and functionality of adenosine receptors and TNFalpha release and NF-kappaB activation.


METHODS
Adenosine receptors were analyzed by saturation binding assays and Western blot analyses. We investigated the potency of typical A(2A) and A(3) agonists in the production of cAMP in control subjects, ERA patients, and RA patients treated with MTX or anti-TNFalpha. In a separate cohort of RA patients, TNFalpha release and NF-kappaB activation were evaluated in plasma and nuclear extracts, respectively.


RESULTS
In ERA patients, we found a high density and altered functionality of A(2A) and A(3) receptors. The binding and functional parameters of A(2A) and A(3) receptors normalized after anti-TNFalpha, but not MTX, treatment. TNFalpha release was increased in ERA patients and in MTX-treated RA patients, whereas in anti-TNFalpha-treated RA patients, release was comparable to that in the controls. NF-kappaB activation was elevated in ERA patients and in MTX-treated RA patients. Anti-TNFalpha treatment mediated decreased levels of NF-kappaB activation.


CONCLUSIONS
A(2A) and A(3) receptor up-regulation in ERA patients and in MTX-treated RA patients was associated with high levels of TNFalpha and NF-kappaB activation. Treatment with anti-TNFalpha normalized A(2A) and A(3) receptor expression and functionality. This new evidence of A(2A) and A(3) receptor involvement opens the possibility of exploiting their potential role in human diseases characterized by a marked inflammatory component.
Varani
Katia
K
University of Ferrara, Ferrara, Italy.
Massara
Alfonso
A
Vincenzi
Fabrizio
F
Tosi
Alice
A
Padovan
Melissa
M
Trotta
Francesco
F
Borea
Pier Andrea
PA
D000068879:Adalimumab; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000378:metabolism*; D016022:Case-Control Studies; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D000069285:Infliximab; D008214:Lymphocytes / Q000378:metabolism / Q000473:pathology; D008297:Male; D008727:Methotrexate / Q000494:pharmacology / Q000627:therapeutic use*; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism / Q000473:pathology; D043705:Receptor, Adenosine A2A / Q000235:genetics / Q000378:metabolism*; D043684:Receptor, Adenosine A3 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents; D016328:NF-kappa B; D043705:Receptor, Adenosine A2A; D043684:Receptor, Adenosine A3; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D000068879:Adalimumab; D008727:Methotrexate