NF-κB enhances hypoxia-driven T-cell immunosuppression via upregulation of adenosine A(2A) receptors.
Hypoxia affects inflammation by modulating T-cell activation via the adenosinergic system. We supposed that, in turn, inflammation influences cell hypoxic behavior and that stimulation of T-cells in inflammatory conditions involves the concerted action of the nuclear factor κB (NF-κB) and the related hypoxia-inducible factor 1α (HIF-1α) on the adenosinergic system. We addressed this hypothesis by monitoring both transcription factors and four adenosinergic signaling parameters - namely adenosine, adenosine deaminase (ADA), adenosine A2A receptor (A2AR) and cAMP - in T-cells stimulated using phorbol myristate acetate and phytohemagglutinin and submitted to hypoxic conditions which were mimicked using CoCl2 treatment. We found that cell viability was more altered in stimulated than in resting cells under hypoxia. Detailed analysis showed that: i) NF-κB activation remained at basal level in resting hypoxic cells but greatly increased following stimulation, stimulated hypoxic cells exhibiting the higher level; ii) HIF-1α production induced by hypoxia was boosted via NF-κB activation in stimulated cells whereas hypoxia increased HIF-1α production in resting cells without further activating NF-κB; iii) A2AR expression and cAMP production increased in stimulated hypoxic cells whereas adenosine level remained unchanged due to ADA regulation; and iv) the presence of H2S, an endogenous signaling molecule in inflammation, reversed the effect of stimulation on cell viability by down-regulating the activity of transcription factors and adenosinergic immunosuppression. We also found that: i) the specific A2AR agonist CGS-21680 increased the suppressive effect of hypoxia on stimulated T-cells, the antagonist ZM-241385 exhibiting the opposite effect; and ii) Rolipram, a selective inhibitor of cAMP-specific phosphodiesterase 4, and 8-Br-cAMP, a cAMP analog which preferentially activates cAMP-dependent protein kinase A (PKA), increased T-cell immunosuppression whereas H-89, a potent and selective inhibitor of cAMP-dependent PKA, restored cell viability. Together, these data indicate that inflammation enhances T-cell sensitivity to hypoxia via NF-κB activation. This process upregulates A2AR expression and enhances cAMP production and PKA activation, resulting in adenosinergic T-cell immunosuppression that can be modulated via H2S.
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Laurie
L
Bruzzese
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Julien
J
Fromonot
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Youlet
Y
By
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Josée-Martine
JM
Durand-Gorde
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Jocelyne
J
Condo
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Nathalie
N
Kipson
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France.
Régis
R
Guieu
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France; Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Biologiques, France.
Emmanuel
E
Fenouillet
Aix-Marseille Université (AMU) and Institut de Recherche Biomédicale des Armées (IRBA), UMR MD2, Faculté de Médecine Nord, Marseille, France; Institut National de la Santé et de la Recherche Médicale (INSERM), France. Electronic address: jean.ruf@univ-amu.fr.
Jean
J
Ruf
D058908:Adenosine A2 Receptor Agonists / Q000494:pharmacology; D058917:Adenosine A2 Receptor Antagonists / Q000494:pharmacology; D015687:Cell Hypoxia; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003035:Cobalt / Q000633:toxicity; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007165:Immunosuppression Therapy; D007546:Isoquinolines / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism*; D043705:Receptor, Adenosine A2A / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013447:Sulfites / Q000633:toxicity*; D013449:Sulfonamides / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D014227:Triazines / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
D058908:Adenosine A2 Receptor Agonists; D058917:Adenosine A2 Receptor Antagonists; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007546:Isoquinolines; D016328:NF-kappa B; D043705:Receptor, Adenosine A2A; D013447:Sulfites; D013449:Sulfonamides; D014227:Triazines; D014230:Triazoles; C097270:ZM 241385; D003035:Cobalt; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; C018021:cobaltous chloride; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C042345:hydrogen sulfite
Adenosine; Adenosine A(2A) receptor; Cell viability; Chemical hypoxia; Hydrogen sulfide