title: Deficiency of scavenger receptor class B type I negatively affects progesterone secretion in human granulosa cells.
abstract: Our goal was to examine the effect of deficiency of the lipoprotein receptor, scavenger receptor class B type I (SR-BI), on progesterone secretion in human granulosa cells (HGL5). Scrambled or SR-BI small interfering RNA [knockdown (KD)] cells were exposed to dimethylsulfoxide [DMSO, vehicle for forskolin (Fo)], Fo, serum, high-density lipoprotein, low-density lipoprotein (LDL), or Fo plus lipoproteins or serum for 24 h. Progesterone secretion was lower in all of the SR-BI KD cells regardless of treatment. We examined progesterone secretion in SR-BI KD, LDL receptor KD, and double KD cells incubated with DMSO, Fo, LDL, or Fo + LDL for 6-24 h. As compared with scrambled cells, progesterone secretion was lower in SR-BI and double KD cells regardless of treatment; whereas progesterone secretion was only lower in LDL receptor KD cells incubated with LDL and Fo + LDL. We measured phosphorylation of hormone-sensitive lipase (pHSL) expression, intracellular total cholesterol (TC) mass, and progesterone secretion in scrambled and SR-BI KD cells incubated with DMSO or Fo for 2-24 h. The expression of pHSL was similar between the cells and conditions. The mean change in TC mass and progesterone secretion was lower in SR-BI KD cells exposed to DMSO and Fo. Incubating SR-BI KD cells with 22-hydroxy cholesterol did not overcome the reduction in progesterone secretion. At different time points, RNA expression of steroidogenic acute regulatory protein, side-chain cleavage, and 3β-hydroxysteroid dehydrogenase was significantly lower in SR-BI KD cells incubated with Fo. In conclusion, SR-BI protein deficiency, in part, might explain progesterone deficiency in some infertile women.
authors.affiliation: Department of Medicine, Division of Endocrinology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21215, USA.
authors.forename: Antonina
authors.initials: A
authors.lastname: Kolmakova
authors.forename: Jiangxia
authors.initials: J
authors.lastname: Wang
authors.forename: Rebecca
authors.initials: R
authors.lastname: Brogan
authors.forename: Charles
authors.initials: C
authors.lastname: Chaffin
authors.forename: Annabelle
authors.initials: A
authors.lastname: Rodriguez
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism / Q000494:pharmacology; D008077:Lipoproteins, LDL / Q000378:metabolism / Q000494:pharmacology; D011374:Progesterone / Q000378:metabolism*; D034741:RNA, Small Interfering; D011863:Radioimmunoassay; D011973:Receptors, LDL / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051122:Scavenger Receptors, Class B / Q000235:genetics / Q000378:metabolism*
chemical_list: D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D034741:RNA, Small Interfering; D011973:Receptors, LDL; C495124:SCARB1 protein, human; D051122:Scavenger Receptors, Class B; D011374:Progesterone