Expression and localization of adipophilin and perilipin in human fetal membranes: association with lipid bodies and enzymes involved in prostaglandin synthesis.
Lipid storage droplets (LSDs) are subcellular storage depots for triglycerides (TGs) and cholesterol esters surrounded by specific populations of proteins that are necessary for their formation. We have previously described the appearance of LSDs in human fetal membranes with advancing gestation and labor. Perilipin and adipophilin are functional/structural proteins located on the surfaces of intracellular LSDs. Adipophilin and perilipin were both immunolocalized to the amnion epithelium and amnion fibroblasts in human fetal membranes. Adipophilin was also localized to the choriodecidual layer, whereas perilipin was localized to the chorion trophoblasts. Although immunohistochemical data show an apparent increase in adipophilin, but not perilipin, expression in fetal membranes with advancing gestation and labor, Western analysis of tissue homogenate supernatant revealed no significant changes in adipophilin and perilipin expression. However, Western analysis of the floating lipid-rich layer from the tissue homogenate revealed an abundance of adipophilin and perilipin as well as other enzymes (cytosolic phospholipase A2, prostaglandin endoperoxide, and microsomal-associated prostaglandin E synthase-1) involved in prostaglandin synthesis. The association of these enzymatically active proteins with LSDs suggests that LSDs may be foci for signaling via the arachidonic acid cascade in fetal membranes. The structural and functional roles of adipophilin and perilipin in gestation and labor remain to be determined.
Meadows
Juliana W
JW
Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267-0526, USA.
Pitzer
Brad
B
Brockman
Diane E
DE
Myatt
Leslie
L
D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins; D051546:Cyclooxygenase 2; D005321:Extraembryonic Membranes / Q000737:chemistry*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019746:Intramolecular Oxidoreductases / Q000032:analysis; D008055:Lipids / Q000032:analysis*; D008565:Membrane Proteins / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D051379:Mice; D008970:Molecular Weight; D010455:Peptides; D000070778:Perilipin-1; D000070780:Perilipin-2; D010741:Phospholipases A / Q000032:analysis; D054467:Phospholipases A2; D010750:Phosphoproteins / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D011247:Pregnancy; D000071876:Prostaglandin-E Synthases; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis; D011453:Prostaglandins / Q000096:biosynthesis*; D011817:Rabbits
D002352:Carrier Proteins; D008055:Lipids; D008565:Membrane Proteins; C000602982:PLIN2 protein, human; D010455:Peptides; D000070778:Perilipin-1; D000070780:Perilipin-2; D010750:Phosphoproteins; C000602983:Plin2 protein, mouse; D011453:Prostaglandins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D010741:Phospholipases A; D054467:Phospholipases A2; D019746:Intramolecular Oxidoreductases; D000071876:Prostaglandin-E Synthases