title: Lipopolysaccharide-induced expression of microsomal prostaglandin E synthase-1 mediates late-phase PGE2 production in bone marrow derived macrophages.
abstract: Cyclooxygenase (COX)-2 expression and release of prostaglandins (PGs) by macrophages are consistent features of lipopolysaccharide (LPS)-induced macrophage inflammation. The two major PGs, PGE(2) and PGD(2), are synthesized by the prostanoid isomerases, PGE synthases (PGES) and PGD synthases (PGDS), respectively. Since the expression profile and the individual role of these prostanoid isomerases-mediated inflammation in macrophages has not been defined, we examined the LPS-stimulated PGs production pattern and the expression profile of their synthases in the primary cultured mouse bone marrow derived macrophages (BMDM). Our data show that LPS induced both PGE(2) and PGD(2) production, which was evident by ∼8 hrs and remained at a similar ratio (∼1∶1) in the early phase (≤12 hrs) of LPS treatment. However, PGE(2) production continued increase further in the late phase (16-24 hrs); whereas the production of PGD(2) remained at a stable level from 12 to 24 hrs post-treatment. In response to LPS-treatment, the expression of both COX-2 and inducible nitric oxide synthase (iNOS) was detected within 2 to 4 hrs; whereas the increased expression of microsomal PGES (mPGES)-1 and a myeloid cell transcription factor PU.1 did not appear until later phase (≥12 hrs). In contrast, the expression of COX-1, hematopoietic-PGDS (H-PGDS), cytosolic-PGES (c-PGES), or mPGES-2 in BMDM was not affected by LPS treatment. Selective inhibition of mPGES-1 with either siRNA or isoform-selective inhibitor CAY10526, but not mPGES-2, c-PGES or PU.1, attenuated LPS-induced burst of PGE(2) production indicating that mPGES-1 mediates LPS-induced PGE(2) production in BMDM. Interestingly, selective inhibition of mPGES-1 was also associated with a decrease in LPS-induced iNOS expression. In summary, our data show that mPGES-1, but not mPGES-2 or c-PGES isomerase, mediates LPS-induced late-phase burst of PGE(2) generation, and regulates LPS-induced iNOS expression in BMDM.
authors.affiliation: Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA. leixiao@uic.edu
authors.forename: Lei
authors.initials: L
authors.lastname: Xiao
authors.forename: Magdalena
authors.initials: M
authors.lastname: Ornatowska
authors.forename: Guiqing
authors.initials: G
authors.lastname: Zhao
authors.forename: Hongmei
authors.initials: H
authors.lastname: Cao
authors.forename: Rui
authors.initials: R
authors.lastname: Yu
authors.forename: Jing
authors.initials: J
authors.lastname: Deng
authors.forename: Yongchao
authors.initials: Y
authors.lastname: Li
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhao
authors.forename: Ruxana T
authors.initials: RT
authors.lastname: Sadikot
authors.forename: John W
authors.initials: JW
authors.lastname: Christman
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D051545:Cyclooxygenase 1; D015232:Dinoprostone / Q000096:biosynthesis*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D019746:Intramolecular Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D054834:Lipocalins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008565:Membrane Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D061251:Primary Cell Culture; D015230:Prostaglandin D2 / Q000096:biosynthesis; D000071876:Prostaglandin-E Synthases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D013876:Thiophenes / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D015107:4-Butyrolactone; D051545:Cyclooxygenase 1; D015232:Dinoprostone; D004791:Enzyme Inhibitors; D019746:Intramolecular Oxidoreductases; D054834:Lipocalins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D052247:Nitric Oxide Synthase Type II; D015230:Prostaglandin D2; D000071876:Prostaglandin-E Synthases; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D013876:Thiophenes; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; C569291:4-(benzo(b)thiophen-2-yl)-3-bromo-5-hydroxydihydrofuran-2(3H)-one; C496317:Nos2 protein, mouse; C496512:Ptgs1 protein, mouse; C022466:prostaglandin R2 D-isomerase; C000605865:Ptges protein, mouse; C000605866:Ptges2 protein, mouse