A peptide of the alpha 3(IV) chain of type IV collagen modulates stimulated neutrophil function via activation of cAMP-dependent protein kinase and Ser/Thr protein phosphatase.
Previous reports from our laboratories showed that type IV collagen from anterior lens capsule (ALC) inhibited stimulated neutrophil function. This property was shown to reside in the region comprising residues 185-203 of the non-collagenous domain (NC1) of the alpha 3(IV) chain. We also reported that ALC-type IV collagen or the synthetic alpha 3(IV) 185-203 peptide, induced a rise in intracellular cAMP which persisted for up to 60 minutes. In the present work we extend our previous studies on signal transduction by alpha 3(IV) 185-203 and we provide new data showing the involvement of cAMP-dependent PKA and protein phosphatases. The data also show that the alpha 3(IV) peptide triggered a rise in intracellular calcium that was dependent on phospholipase C activation. Inhibitors of the Ca(2+)/calmodulin system suppressed both the alpha 3(IV) 185-203 peptide-induced cAMP increase and the inhibitory activity of the peptide on f-Met-Leu-Phe triggered O(2)(-) generation. When alpha 3(IV) 185-203 peptide-induced calcium mobilization was blocked by U-73122, an inhibitor of phospholipase C activation, or by BAPTA/AM, a chelator of intracellular calcium, the inhibitory effect of the peptide on PMA-triggered O(2)(-) production was also abolished. These findings provide evidence that signal transduction by the alpha 3(IV) peptide occurs via pathways which involve calcium. Indeed, the cAMP increase was shown to be mediated by adenosine and adenosine A2 receptors and required calcium elevation, since adenosine deaminase, theophilline, dimethylpropargylxanthine, trifluoperazine or autocamtide-2 related inhibitory peptide, suppressed the activity of the alpha 3(IV) peptide. The inhibitory effect of the peptide on f-Met-Leu-Phe-induced O(2)(-) generation was slightly affected by 1 microM KT5720 or H89, two inhibitors of cAMP-dependent PKA, but was completely suppressed by 10 nM calyculin A or 10 microM okadaic acid, two inhibitors of ser/thr phosphatases. These results suggest that Ser/Thr protein phosphatases and/or cAMP-dependent PKA are involved in signal transduction by the alpha 3(IV) 185-203 peptide and is consistent with the concept that adenosine receptor occupancy modulates neutrophil function.
Fawzi
A
A
Laboratoire de Biochimie, Faculté de Médecine, UPRESA CNRS 6021, IFR 53 Biomolécules, 51 Rue Cognacq Jay, 51095 cedex, Reims, France.
Robinet
A
A
Monboisse
J C
JC
Ziaie
Z
Z
Kefalides
N A
NA
Bellon
G
G
D000241:Adenosine / Q000378:metabolism; D000595:Amino Acid Sequence; D001324:Autoantigens / Q000737:chemistry / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002227:Carbazoles; D002614:Chelating Agents / Q000494:pharmacology; D003094:Collagen / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D024141:Collagen Type IV; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008387:Marine Toxins; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000276:immunology*; D019319:Okadaic Acid / Q000494:pharmacology; D010080:Oxazoles / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011758:Pyrroles / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D016897:Respiratory Burst / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology
D001324:Autoantigens; D002227:Carbazoles; D002614:Chelating Agents; D024141:Collagen Type IV; D018492:Dopamine Antagonists; D004791:Enzyme Inhibitors; D004963:Estrenes; D007211:Indoles; D008387:Marine Toxins; D010080:Oxazoles; D010446:Peptide Fragments; D010726:Phosphodiesterase Inhibitors; D011758:Pyrroles; D011760:Pyrrolidinones; C089942:collagen alpha3(IV) 185-203; C057112:type IV collagen alpha3 chain; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C074854:U 73343; D019319:Okadaic Acid; D014268:Trifluoperazine; D004533:Egtazic Acid; C057416:KT 5720; D019284:Thapsigargin; C059041:calyculin A; D003094:Collagen; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases; D000241:Adenosine; D002118:Calcium