Calcium-sensing soluble adenylyl cyclase mediates TNF signal transduction in human neutrophils.
Through chemical screening, we identified a pyrazolone that reversibly blocked the activation of phagocyte oxidase (phox) in human neutrophils in response to tumor necrosis factor (TNF) or formylated peptide. The pyrazolone spared activation of phox by phorbol ester or bacteria, bacterial killing, TNF-induced granule exocytosis and phox assembly, and endothelial transmigration. We traced the pyrazolone's mechanism of action to inhibition of TNF-induced intracellular Ca2+ elevations, and identified a nontransmembrane ("soluble") adenylyl cyclase (sAC) in neutrophils as a Ca2+-sensing source of cAMP. A sAC inhibitor mimicked the pyrazolone's effect on phox. Both compounds blocked TNF-induced activation of Rap1A, a phox-associated guanosine triphosphatase that is regulated by cAMP. Thus, TNF turns on phox through a Ca2+-triggered, sAC-dependent process that may involve activation of Rap1A. This pathway may offer opportunities to suppress oxidative damage during inflammation without blocking antimicrobial function.
Han
Hyunsil
H
Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA.
Stessin
Alexander
A
Roberts
Julia
J
Hess
Kenneth
K
Gautam
Narinder
N
Kamenetsky
Margarita
M
Lou
Olivia
O
Hyde
Edward
E
Nathan
Noah
N
Muller
William A
WA
Buck
Jochen
J
Levin
Lonny R
LR
Nathan
Carl
C
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D015550:Cell Degranulation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects* / Q000502:physiology; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D047069:Pyrazolones / Q000494:pharmacology; D044169:Receptors, Calcium-Sensing / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism
D000894:Anti-Inflammatory Agents, Non-Steroidal; D047069:Pyrazolones; C430803:RAP1A protein, human; D044169:Receptors, Calcium-Sensing; D014409:Tumor Necrosis Factor-alpha; C038362:pyrazolone; D000242:Cyclic AMP; D010088:Oxidoreductases; D020827:rap1 GTP-Binding Proteins; D000262:Adenylyl Cyclases