P2X(1) and P2X(3) purinergic receptors differentially modulate the inflammatory response in human osteoarthritic synovial fibroblasts.
OBJECTIVE
P2X receptors are membrane ion channels activated by extracellular adenosine 5'-triphosphate (ATP) which contribute to various physiological processes. The present study describes in synovial fibroblasts (SFs) obtained from osteoarthritis (OA) patients and in SW 982 cells derived from human synovial sarcoma a pharmacological characterization of P2X(1) and P2X(3) receptors implicated in the modulation of inflammatory processes in joint diseases.


METHODS
mRNA, western blotting, saturation and competition binding experiments were used to characterize purinergic receptors. From a functional point of view nuclear factor kappaB (NF-kappaB) activation, tumour necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and prostaglandin E(2) (PGE(2)) production were evaluated by means of enzyme-linked immunosorbent assays.


RESULTS
P2X(1) and P2X(3) receptors were present with high affinity and density. Selected purinergic agonists and antagonists exhibited a different thermodynamic behavior. P2X(1) receptors showed an anti-inflammatory effect reducing NF-kappaB activation and TNF-alpha release whilst P2X(3) receptors mediated opposite response. No effect was mediated by P2X(1) and P2X(3) receptors on IL-6 and PGE(2) production.


CONCLUSIONS
SFs from OA patients and SW 982 cells similarly express P2X(1) and P2X(3) receptors which are able to modulate in opposite way some functional responses closely associated with inflammation suggesting that purinergic receptors may represent a potential target in therapeutic anti-inflammatory joint interventions.
Varani
Katia
K
Department of Clinical and Experimental Medicine, University of Ferrara, 44100 Ferrara, Italy.
De Mattei
Monica
M
Vincenzi
Fabrizio
F
Tosi
Alice
A
Targa
Martina
M
Masieri
Federica F
FF
Pellati
Agnese
A
Massari
Leo
L
Borea
Pier Andrea
PA
D002460:Cell Line; D015232:Dinoprostone / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D010003:Osteoarthritis / Q000378:metabolism*; D010641:Phenotype; D011485:Protein Binding; D018048:Receptors, Purinergic P2 / Q000235:genetics / Q000378:metabolism*; D058469:Receptors, Purinergic P2X; D058477:Receptors, Purinergic P2X3; D013583:Synovial Membrane / Q000166:cytology*; D013816:Thermodynamics; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D018836:Inflammation Mediators; D015850:Interleukin-6; D016328:NF-kappa B; C546407:P2RX3 protein, human; D018048:Receptors, Purinergic P2; D058469:Receptors, Purinergic P2X; D058477:Receptors, Purinergic P2X3; D014409:Tumor Necrosis Factor-alpha; D015232:Dinoprostone