Structural analogs of pulmonary surfactant phosphatidylglycerol inhibit toll-like receptor 2 and 4 signaling.
The pulmonary surfactant phospholipid, 1-palmitoyl-2-oleoylphosphatidylglycerol (POPG), potently inhibits toll-like receptor (TLR)2 and TLR4 signaling from the cell surface of macrophages. Analogs of POPG that vary in polar head group length, hydroxylation, and alkyl branching were synthesized using a phospholipase D-catalyzed transphosphatidylation reaction and a 1-palmitoyl-2-oleoyl phosphatidylcholine substrate. Lipid analogs with C3 and C4 alkyl head group length (POP-propanol and POP-butanol) are less effective than POPG as TLR2 and TLR4 antagonists. However, adding a hydroxyl group at the alkyl chain 3- or 4-position (POP-propanediols or POP-butanediols) greatly increased their inhibitory effects against TLR2 and TLR4. POP-2',2'-dimethylpropanediol is a weak inhibitor of TLR2 and TLR4 activation that results in arachidonic acid release, but an effective inhibitor of TLR4 activation that results in TNF-α production. Addition of an amino group at the alkyl-2 position (POP-2'-aminopropanediol) completely abolished the antagonism of TLRs 2 and 4. Multiple analogs strongly bind to the TLR4 coreceptors, cluster of differentiation 14 (CD14) and myeloid differentiation 2, but competition for di[3-deoxy-D-manno-octulosonyl]-lipid A binding to CD14 is the best predictor of biological activity at the cellular level. Collectively, these findings identify new compounds for antagonizing TLR2 and TLR4 activation and define structural properties of POPG analogs for discriminating between two TLR systems.
Departments of Medicine, Basic Science Section, National Jewish Health, Denver, CO 80206.
Pitchaimani
P
Kandasamy
Departments of Medicine, Basic Science Section, National Jewish Health, Denver, CO 80206.
Mari
M
Numata
Department of Pharmacology, University of Colorado, Aurora, CO 80045.
Karin Zemski
KZ
Berry
Departments of Medicine, Basic Science Section, National Jewish Health, Denver, CO 80206.
Rachel
R
Fickes
Pediatrics, National Jewish Health, Denver, CO 80206.
Christina C
CC
Leslie
Department of Pharmacology, University of Colorado, Aurora, CO 80045.
Robert C
RC
Murphy
Departments of Medicine, Basic Science Section, National Jewish Health, Denver, CO 80206 voelkerd@njhealth.org.
Dennis R
DR
Voelker
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects; D015777:Eicosanoids / Q000008:administration & dosage / Q000737:chemistry; D004731:Endotoxins / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D007249:Inflammation / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010715:Phosphatidylglycerols / Q000008:administration & dosage* / Q000737:chemistry; D011663:Pulmonary Surfactants / Q000008:administration & dosage / Q000737:chemistry; D000067996:RAW 264.7 Cells; D015398:Signal Transduction / Q000187:drug effects; D051195:Toll-Like Receptor 2 / Q000037:antagonists & inhibitors / Q000235:genetics*; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics*
D015777:Eicosanoids; D004731:Endotoxins; D018950:Lipopolysaccharide Receptors; D010715:Phosphatidylglycerols; D011663:Pulmonary Surfactants; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol
anti-inflammatory; eicosanoids; endotoxin