G16-mediated activation of nuclear factor kappaB by the adenosine A1 receptor involves c-Src, protein kinase C, and ERK signaling.
The G(i)-linked adenosine A1 receptor has been shown to mediate anti-inflammatory actions, possibly via modulation of the transcription factor nuclear factor-kappaB (NFkappaB). Here we demonstrate that an adenosine A1 agonist, N(6)-cyclohexyladenosine (CHA), activated IKKalpha/beta phosphorylation through PTX-insensitive G proteins in human lymphoblastoma Reh cells. To delineate the mechanism of action, different PTX-insensitive G proteins were expressed in human embryonic kidney 293 cells. Only Galpha(16) supported the CHA-induced IKK phosphorylation and NFkappaB-driven luciferase activity in time-dependent, dose-dependent, and PTX-insensitive manners. Gbetagamma subunits also modulated IKK/NFkappaB, as indicated by the stimulatory actions of Gbeta(1)gamma(2) and the abrogation of CHA-induced response by transducin. The participation of phospholipase Cbeta, protein kinase C, and calmodulin-dependent kinase II in CHA-induced IKK/NFkappaB activation were demonstrated by employing specific inhibitors and dominant-negative mutants. Inhibition of c-Src and numerous intermediates along the extracellular signal-regulated (ERK) kinase cascade including Ras, Raf-1 kinase, and MEK1/2 abolished the CHA-induced IKK/NFkappaB activation. Although c-Jun N-terminal kinase and p38 MAPK were also activated by CHA, they were not required for the IKK/NFkappaB regulation. Similar results were obtained using Reh cells. These data suggest that the G(16)-mediated activation of IKK/NFkappaB by CHA required a complex signaling network composed of multiple intermediates.
Liu
Andrew M F
AM
Department of Biochemistry, Molecular Neuroscience Center, and Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Wong
Yung H
YH
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000081247:CSK Tyrosine-Protein Kinase; D002460:Cell Line; D045744:Cell Line, Tumor; D003513:Cycloheximide / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D005799:Genes, Dominant; D017930:Genes, Reporter; D020962:Heterotrimeric GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D051550:I-kappa B Kinase; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D054799:Phospholipase C beta; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors; D015293:Transducin / Q000378:metabolism; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D019061:src-Family Kinases
D018076:DNA, Complementary; D007527:Isoenzymes; D016328:NF-kappa B; D011500:Protein Synthesis Inhibitors; D043682:Receptor, Adenosine A1; C027513:N(6)-cyclohexyladenosine; D003513:Cycloheximide; D008156:Luciferases; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; D011493:Protein Kinase C; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D010738:Type C Phospholipases; D054799:Phospholipase C beta; C112631:G protein alpha 16; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins; D015293:Transducin; D000241:Adenosine