title: Synthetic High-Density Lipoprotein (sHDL) Inhibits Steroid Production in HAC15 Adrenal Cells.
abstract: High density lipoprotein (HDL) transported cholesterol represents one of the sources of substrate for adrenal steroid production. Synthetic HDL (sHDL) particles represent a new therapeutic option to reduce atherosclerotic plaque burden by increasing cholesterol efflux from macrophage cells. The effects of the sHDL particles on steroidogenic cells have not been explored. sHDL, specifically ETC-642, was studied in HAC15 adrenocortical cells. Cells were treated with sHDL, forskolin, 22R-hydroxycholesterol, or pregnenolone. Experiments included time and concentration response curves, followed by steroid assay. Quantitative real-time RT-PCR was used to study mRNA of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, lanosterol 14-α-methylase, cholesterol side-chain cleavage enzyme, and steroid acute regulatory protein. Cholesterol assay was performed using cell culture media and cell lipid extracts from a dose response experiment. sHDL significantly inhibited production of cortisol. Inhibition occurred in a concentration- and time-dependent manner and in a concentration range of 3μM-50μM. Forskolin (10μM) stimulated cortisol production was also inhibited. Incubation with 22R-hydroxycholesterol (10μM) and pregnenolone (10μM) increased cortisol production, which was unaffected by sHDL treatment. sHDL increased transcript levels for the rate-limiting cholesterol biosynthetic enzyme, 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase. Extracellular cholesterol assayed in culture media showed a positive correlation with increasing concentration of sHDL, whereas intracellular cholesterol decreased after treatment with sHDL. The current study suggests that sHDL inhibits HAC15 adrenal cell steroid production by efflux of cholesterol, leading to an overall decrease in steroid production and an adaptive rise in adrenal cholesterol biosynthesis.
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Taylor
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: Aalok R
authors.initials: AR
authors.lastname: Sanjanwala
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Morin
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Rowland-Fisher
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: Kyle
authors.initials: K
authors.lastname: Anderson
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: Anna
authors.initials: A
authors.lastname: Schwendeman
authors.affiliation: Departments of Molecular and Integrative Physiology and Internal Medicine (M.J.T., A.R.S., K.A.,W.E.R.)., University of Michigan, Ann Arbor, Michigan 48109; Medical College of Georgia (A.R.S.), Georgia Regents University, Augusta, Georgia 30912; Department of Pharmaceutical Science (E.E.M., A.S.), Biointerfaces Institute, University of Michigan, Ann Arbor, Michigan 48109; and Department of Medicinal Chemistry (E.R.-F.), College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109.
authors.forename: William E
authors.initials: WE
authors.lastname: Rainey
mesh_terms: D000305:Adrenal Cortex Hormones / Q000096:biosynthesis*; D000311:Adrenal Glands / Q000187:drug effects* / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D006854:Hydrocortisone / Q000096:biosynthesis; D008075:Lipoproteins, HDL / Q000138:chemical synthesis / Q000494:pharmacology*; D053858:Metabolic Networks and Pathways / Q000187:drug effects / Q000235:genetics
chemical_list: D000305:Adrenal Cortex Hormones; D008075:Lipoproteins, HDL; D000324:Adrenocorticotropic Hormone; D002784:Cholesterol; D006854:Hydrocortisone