Identification of an intracellular receptor for lysophosphatidic acid (LPA): LPA is a transcellular PPARγ agonist
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Machine scores (provisional)
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- Teacher spread
- 0.247 · how far apart the two teachers sit on this one work
- Validation status
score_only:v0-immature-baseline· verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it
Abstract
Lysophosphatidic acid (LPA) is a pluripotent lipid mediator acting through plasma membrane-associated LPA(x) receptors that transduce many, but not all, of its effects. We identify peroxisome proliferator-activated receptor gamma (PPARgamma) as an intracellular receptor for LPA. The transcription factor PPARgamma is activated by several lipid ligands, but agonists derived from physiologic signaling pathways are unknown. We show that LPA, but not its precursor phosphatidic acid, displaces the drug rosiglitazone from the ligand-binding pocket of PPARgamma. LPA and novel LPA analogs we made stimulated expression of a PPAR-responsive element reporter and the endogenous PPARgamma-controlled gene CD36, and induced monocyte lipid accumulation from oxidized low-density lipoprotein via the CD36 scavenger receptor. The synthetic LPA analogs were effective PPARgamma agonists, but were poor ones for LPA(1), LPA(2), or LPA(3) receptor transfected cells. Transfection studies in yeast, which lack nuclear hormone and LPA(x) receptors, show that LPA directly activates PPARgamma. A major growth factor of serum is LPA generated by thrombin-activated platelets, and media from activated platelets stimulated PPARgamma function in transfected RAW264.7 macrophages. This function was suppressed by ectopic LPA-acyltransferase expression. LPA is a physiologic PPARgamma ligand, placing PPARgamma in a signaling pathway, and PPARgamma is the first intracellular receptor identified for LPA. Moreover, LPA produced by stimulated plasma platelets activates PPARgamma in nucleated cells.
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The record
- Venue
- Proceedings of the National Academy of Sciences
- Topic
- Sphingolipid Metabolism and Signaling
- Field
- Biochemistry, Genetics and Molecular Biology
- Canadian institutions
- —
- Funders
- National Heart, Lung, and Blood InstituteNational Institutes of HealthMcMaster University
- Keywords
- Lysophosphatidic acidCell biologyReceptorSignal transductionBiologyTransfectionChemistryBiochemistry
- Has abstract in OpenAlex
- yes