Inhibition of pro-inflammatory cytokine production by the dual p38/JNK2 inhibitor BIRB796 correlates with the inhibition of p38 signaling.
The characterization of the potent p38 inhibitor BIRB796 as a dual inhibitor of p38/Jun N-terminal kinases (JNK) mitogen-activated protein kinases (EC 2.7.11.24) has complicated the interpretation of its reported anti-inflammatory activity. To better understand the contribution of JNK2 inhibition to the anti-inflammatory activities of BIRB796, we explored the relationship between the effects of BIRB796 and analogues on cytokine production and on cellular p38 and JNK signaling. We determined the binding affinity for BIRB796 and structural analogues to p38alpha and JNK2 and characterized compound 2 as a p38 inhibitor that binds to p38alpha with an affinity equivalent to BIRB796 but does not bind to any of the JNK isoforms. High-content imaging enabled us to show that the inhibition of p38 signaling by BIRB796 and analogues correlates with the ability of these compounds to inhibit the lipopolysaccharide (LPS)-induced TNF-alpha production in THP-1 monocytes. This finding was extended to cytokine release by disease-relevant human primary cells: to the production of TNF-alpha by peripheral blood mononuclear cells, and of IL-8 by neutrophils. Furthermore, BIRB796 and compound 2 inhibited the production of TNF-alpha in THP-1 monocytes and the IL-12/IL-18-induced production of interferon-gamma in human T-cells with similar potencies. In contrast, cellular JNK signaling in response to cytokines or stress stimuli was only weakly inhibited by BIRB796 and analogues and not affected by compound 2. In summary, our data suggest that p38 inhibition alone is sufficient to completely suppress cytokine production and that the added inhibition of JNK2 does not significantly contribute to the effects of BIRB796 on cytokine production.
Gruenbaum
Lore M
LM
Department of Drug Discovery Support, Boehringer Ingelheim Pharmaceuticals, Research and Development Center, 900 Ridgebury Road, P.O. Box 368, Ridgefield, CT 06877, USA. lore.gruenbaum@boehringer-ingelheim.com
Schwartz
Racheline
R
Woska
Joseph R
JR
DeLeon
Rodney P
RP
Peet
Gregory W
GW
Warren
Thomas C
TC
Capolino
Alison
A
Mara
Lisa
L
Morelock
Maurice M
MM
Shrutkowski
Anthony
A
Jones
Jessi Wildeson
JW
Pargellis
Christopher A
CA
D016207:Cytokines / Q000096:biosynthesis*; D006367:HeLa Cells; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D048056:Mitogen-Activated Protein Kinase 9 / Q000037:antagonists & inhibitors*; D009281:Naphthalenes / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*; D010671:Phenylurea Compounds
D016207:Cytokines; D018836:Inflammation Mediators; D048056:Mitogen-Activated Protein Kinase 9; D009281:Naphthalenes; D047428:Protein Kinase Inhibitors; D011720:Pyrazoles; D048051:p38 Mitogen-Activated Protein Kinases; C452139:doramapimod; D010671:Phenylurea Compounds