title: Fresh mouse peritoneal macrophages have low scavenger receptor activity.
abstract: Peritoneal macrophages are easily isolated by lavage, suggesting that they are either nonadherent or weakly adherent in situ. Cultured macrophages express class A scavenger receptors (SCR), which mediate Ca2+-independent adhesion in vitro. We examined fresh peritoneal macrophages from mice and from women with endometriosis to determine whether the adherence of these cells was associated with increased expression of class A SCR. Fresh human macrophages were not immunoreactive to SCR antibodies; however, SCR immunoreactivity increased with time in culture. Fresh mouse and human macrophages took up minimal amounts of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine (DiI)-acetyl-low density lipoproteins (Ac-LDL), a class A SCR ligand. Murine macrophages in culture for 24-72 h internalized four times more Ac-LDL than fresh cells. Cells cultured for 2 days incorporated 3.2 times more [14C] oleate than freshly isolated cells (55.7 +/- 7.9 versus 17.6 +/- 3.0 nmol/mg cell protein). In contrast to SCR activity, mouse macrophage SCR mRNA expression was similar in freshly isolated macrophages and those cultured for 3 days. These results suggest that peritoneal macrophages express only low levels of SCR activity in situ and that posttranscriptional regulation after isolation leads to an increase in SCR activity that correlates with adherence of the macrophages in vitro.
authors.affiliation: Department of Gynecology and Obstetrics, School of Medicine, Emory University, Atlanta, GA 30322, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Kim
authors.forename: C
authors.initials: C
authors.lastname: Keshava
authors.forename: A A
authors.initials: AA
authors.lastname: Murphy
authors.forename: R E
authors.initials: RE
authors.lastname: Pitas
authors.forename: S
authors.initials: S
authors.lastname: Parthasarathy
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D002232:Carbocyanines / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins; D051379:Mice; D008856:Microscopy, Fluorescence; D019301:Oleic Acid / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000378:metabolism*; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B; D013997:Time Factors
chemical_list: C035005:3,3'-dihexadecylindocarbocyanine; D002232:Carbocyanines; D005456:Fluorescent Dyes; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B; D019301:Oleic Acid; D003513:Cycloheximide