Fatty acid binding protein 5 controls microsomal prostaglandin E synthase 1 (mPGES-1) induction during inflammation.

5 years ago

Fatty acid binding protein 5 controls microsomal prostaglandin E synthase 1 (mPGES-1) induction during inflammation.

Matthew W Elmes, Martha P Kanjiya, Iwao Ojima, Jerome Falcone, Michelino Puopolo, Maria Gomez, Keith Studholme, Sang Hoon Park, Su Yan, Norbert Smietalo, Yong Lu, Gregory Carbonetti, Martin Kaczocha, Diane Bogdan

Fatty acid binding proteins (FABPs) are intracellular lipid carriers that regulate inflammation, and pharmacological inhibition of FABP5 reduces inflammation and pain. The mechanism(s) underlying the anti-inflammatory effects associated with FABP5 inhibition are poorly understood. Herein, we identify a novel mechanism through which FABP5 modulates inflammation. In mice, intraplantar injection of carrageenan induces acute inflammation that is accompanied by edema, enhanced pain sensitivity, and elevations in pro-inflammatory cytokines and prostaglandin E2 (PGE2). Inhibition of FABP5 reduced pain, edema, cytokine, and PGE2 levels. PGE2 is a major eicosanoid that enhances pain in the setting of inflammation and we focused upon the mechanism(s) through which FABP5 modulates PGE2 production. Cyclooxygenase-2 and microsomal prostaglandin E synthase-1 (mPGES-1) are enzymes upregulated at the site of inflammation and account for the bulk of PGE2 biosynthesis. Pharmacological or genetic FABP5 inhibition suppressed the induction of mPGES-1 but not COX-2 in carrageenan-injected paws, which occurred predominantly in macrophages. The cytokine interleukin 1β (IL-1β) is a major inducer of mPGES-1 during inflammation. Using A549 cells that express FABP5, IL-1β stimulation upregulated mPGES-1 expression, and mPGES-1 induction was attenuated in A549 cells bearing a knockdown of FABP5. IL-1β upregulates mPGES-1 via NF-kB, which activates the mPGES-1 promoter. Knockdown of FABP5 reduced the activation and nuclear translocation of NF-kB, and attenuated mPGES-1 promoter activity. Deletion of NF-kB binding sites within the mPGES-1 promoter abrogated the ability of FABP5 to inhibit mPGES-1 promoter activation. Collectively, these results position FABP5 as a novel regulator of mPGES-1 induction and PGE2 biosynthesis during inflammation.

Publisher URL: http://doi.org/10.1074/jbc.RA118.001593

DOI: 10.1074/jbc.RA118.001593