Lipoproteins and steroid hormone-producing tissues

Gwynne, John T.; Mahaffee, D D

doi:10.1016/0076-6879(86)29098-9

Cited by 15 publications

(4 citation statements)

References 21 publications

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“…In conclusion, the present study shows that bovine and, more importantly, human adrenocortical cells take up massive amounts of HDL-derived CE as a substrate for steroid hormone production in both the basal state and under AngII stimulation. Although blood lipoprotein profiles in human and cow are in favor of LDL (56), and although several earlier reports have concluded that HDL are not effective cholesterol donors for human and bovine steroidogenic cells (17,57,58), our data clearly indicate that adrenocortical cells from these species efficiently take up and metabolize HDLderived CE to support AngII-induced aldosterone biosynthesis. This finding is in keeping with in vivo studies of adrenal function in familial hypercholesterolemia and hypobeta-lipoproteinemia, which have suggested a potential role for HDL in human adrenocortical cholesterol metabolism (59,60).…”

Section: Discussioncontrasting

confidence: 58%

Angiotensin II Promotes Selective Uptake of High Density Lipoprotein Cholesterol Esters in Bovine Adrenal Glomerulosa and Human Adrenocortical Carcinoma Cells Through Induction of Scavenger Receptor Class B Type I

Cherradi

2001

Endocrinology

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Angiotensin II is one of the main physiological regulators of aldosterone biosynthesis in the zona glomerulosa of the adrenal cortex. The hormone stimulates intracellular cholesterol mobilization to the mitochondrion for steroid biosynthesis. Here we have examined whether angiotensin II also modulates exogenous lipoprotein cholesterol ester supply to the steroidogenic machinery and whether this control is exerted on the selective transport of high density lipoprotein-derived cholesterol ester to intracellular lipid droplets through the scavenger receptor class B type I. In bovine adrenal glomerulosa and human NCI H295R adrenocortical carcinoma cells, high density lipoprotein stimulated steroid production. Angiotensin II pretreatment for 24 h potentiated this response. Fluorescence microscopy of cellular uptake of reconstituted high density lipoprotein containing a fluorescent cholesterol ester revealed an initial, time-dependent narrow labeling of the cell membrane followed by an intense accumulation of the fluorescent cholesterol ester within lipid droplets. At all time points, labeling was more pronounced in cells that had been treated for 24 h with angiotensin II. Fluorescence incorporation into cells was prevented by a monoclonal antibody directed against apolipoprotein A-I. Upon quantitative fluorometric determination, cholesterol ester uptake in angiotensin II-treated bovine cells was increased to 175 +/- 15% of controls after 2 h and to 260 +/- 10% after 4 h of exposure to fluorescent high density lipoprotein. The amount of scavenger receptor class B type I protein detected in cells treated with angiotensin II for 24 h reached 203 +/- 12% of that measured in control cells (n = 3, P < 0.01). In contrast, low density lipoprotein receptors were only minimally affected by angiotensin II treatment. This increase in scavenger receptor class B type I protein was associated with a 3-fold induction of scavenger receptor class B type I mRNA, which could be prevented by actinomycin D but not by cycloheximide. Similar results were obtained in the human adenocarcinoma cell line H295R. These observations show that angiotensin II regulates the scavenger receptor class B type I-mediated selective transport of lipoprotein cholesterol ester across the cell membrane as a major source of precursor for mineralocorticoid biosynthesis in both human and bovine adrenal cells.

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Section: Discussioncontrasting

confidence: 58%

Angiotensin II Promotes Selective Uptake of High Density Lipoprotein Cholesterol Esters in Bovine Adrenal Glomerulosa and Human Adrenocortical Carcinoma Cells Through Induction of Scavenger Receptor Class B Type I

Cherradi

2001

Endocrinology

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“…While HDL is the chief source of cholesterol for steroidogenesis in rodent cells (34), both LDL and HDL are able to supply cholesterol for steroidogenesis in the Y-1 BS1 cells (22). Our Ham's F-10 media containing 0.5% BSA.…”

Section: Discussionmentioning

confidence: 99%

Lipoproteins Regulate Expression of the Steroidogenic Acute Regulatory Protein (StAR) in Mouse Adrenocortical Cells

Reyland¹,

Evans²,

White³

2000

Journal of Biological Chemistry

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The production of hormones in steroidogenic tissues is dependent upon the availability of free cholesterol at the inner mitochondrial membrane, the site of the cholesterol side chain cleavage. In adrenocortical cells, adrenocorticotropin (ACTH) 1 stimulates hydrolysis of cholesteryl esters in lipid droplets, and transport of free cholesterol to mitochondria for use in steroid synthesis (1, 2). How free cholesterol in the outer mitochondrial membrane is transferred to the P450-cholesterol side chain cleavage (P450-SCC) complex on the inner mitochondrial membrane is unclear, and the existence of a hormonally regulated, labile protein which facilitates this transfer had been predicted for many years (1, 3). The recently discovered steroidogenic acute regulatory protein (StAR) is a 30-kDa mitochondrial protein which has many of the characteristics of this regulator (3,4). StAR has been demonstrated to promote movement of cholesterol from the outer to the inner mitochondrial membrane where P450-SCC catalyzes the first, and rate-limiting, enzymatic step in steroid synthesis (5, 6). In addition, expression of StAR promotes steroidogenesis, and directly facilitates the transfer of cholesterol and other sterols in reconstituted mitochondria (7-9). Perhaps the most convincing evidence that StAR is critical for this process in vivo is the observation by Miller and others (10, 11) that mutations in the StAR gene cause congenital lipoid adrenal hypoplasia. In this autosomal recessive disorder, gonadal and adrenal steroid production are blocked at the level of cholesterol side chain cleavage, resulting in a massive accumulation of cholesterol in the adrenal glands (10). Likewise, mice in which the StAR gene is disrupted have a severe reduction in corticosterone synthesis and accumulate massive lipid deposits in their adrenal cortex (12).Expression of StAR is acutely regulated in response to hormonal stimulation by a process which does not require de novo protein synthesis (5). Phosphorylation of StAR has also been demonstrated to regulate its steroidogenic activity (13). cAMPdependent protein kinase (PKA), as well as the transcription factors steroidogenic factor-1 (SF-1) and C/EBP␤, are required for basal transcription of StAR (14 -19). Other reports demonstrate that StAR transcription can be regulated by oxysterols (20) and agents known to increase cellular calcium can also regulate StAR transcription (21). Since the net result of ACTH stimulation is an increase in free cholesterol at the outer mitochondrial membrane, the current studies were undertaken to ask if the expression of StAR is regulated directly by lipoproteins, the major source of cholesterol for steroid synthesis in adrenocortical cells. Our studies demonstrate that lipoproteins regulate StAR expression by a mechanism that is dependent on cAMP-dependent protein kinase, and the transcription factor SF-1. The regulation of StAR expression by cholesterol may represent a positive feedback circuit designed to maintain maximal output of steroid hormone. * This work ...

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“…Apolipoprotein N is related to the cholesterol transport regulatory protein apolipoprotein F ( APOF ) and has been previously identified in the HDL and LDL fractions of bovine ovarian follicular fluid as well as in the HDL fraction of bovine serum ( O′Bryan et al, 2004 ). HDLs are involved in the regulation and support of gonadal steroidogenesis, and the association between ApoN and HDL/LDL in follicular fluid suggests that it may have a role in transport of cholesterol or fatty acids, and ultimately in ovarian steroidogenesis ( Andersen and Dietschy, 1978 ; Gwynne and Strauss, 1982 ; Gwynne and Mahaffee, 1986 ; O′Bryan et al, 2004 ). The occurrence of increased ApoN abundance in luteal tissue of gilts supplemented with 60 ppm Mn–amino acid complex in concert with decreased luteal P 4 concentrations ( Studer et al, 2021 ) gives reason to speculate that increased ApoN is indicative of a cellular response to generate additional cholesterol available for increased luteal P 4 production.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the molecular response of corpora lutea to manganese–amino acid complex supplementation in gilts

Studer

Kiefer

Goetz

et al. 2021

Journal of Animal Science

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Porcine pregnancy establishment and maintenance is dependent on the formation of functional corpora lutea (CL). Manganese (Mn) is critical for CL function as it is a cofactor for Mn superoxide dismutase (MnSOD) and enzymes involved in cholesterol synthesis. Previously we have shown luteal Mn content increased and luteal progesterone (P4) concentration decreased in the CL of gilts fed diets supplemented with a Mn-amino acid complex (Availa-Mn; Zinpro Corporation) compared to controls fed Mn sulfate. Importantly, serum P4 increased from 0 (estrus onset) to 12 days post estrus (dpe), as expected, but P4 abundance in circulation was not affected by dietary Mn source (P = 0.15). We hypothesized that a more bioavailable Mn source (which results in increased luteal Mn content) would alter the luteal proteome and abundance of mRNA associated with steroid biogenesis during the mid-luteal phase of the estrous cycle. Post-pubertal gilts (n = 32) were assigned to one of four gestation diets. The control diet (CON) contained 20 ppm of supplemental Mn in the form of Mn sulfate. Three additional diets included 20 (TRT1), 40 (TRT2), or 60 (TRT3) ppm of supplemental Mn in the form of a Mn-amino acid complex instead of Mn sulfate. Dietary treatment began at estrus synchronization (approximately 20 days before estrus) and continued through 12 dpe when gilts were euthanized and tissues were collected. Protein and total RNA extracts from the CL were used for proteomic analysis via label-free liquid-chromatography with tandem mass-spectrometry (LC-MS/MS) to assess global protein abundance and quantitative real-time PCR to assess specific mRNA abundance, respectively. Compared to CON, 188, 382, and 401 proteins were differentially abundant (P < 0.10) in TRT1, TRT2, and TRT3, respectively. Gene Ontology (GO) enrichment software revealed proteins involved in P4 signaling and cholesterol synthesis were downregulated in CL of gilts fed Mn-amino acid complex compared to controls. Quantitative real-time PCR showed relative transcript abundance of genes encoding steroidogenic enzymes (CYP11A1 and StAR) in CL tissue were decreased in gilts from TRT2 compared to CON (P = 0.02), but TRT1 and TRT3 were not affected (P ≥ 0.30). Collectively, these data support our hypothesis that a more bioavailable dietary Mn source may influence luteal function by altering the abundance of protein and mRNA involved in steroidogenesis.

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Lipoproteins and steroid hormone-producing tissues

Cited by 15 publications

References 21 publications

Angiotensin II Promotes Selective Uptake of High Density Lipoprotein Cholesterol Esters in Bovine Adrenal Glomerulosa and Human Adrenocortical Carcinoma Cells Through Induction of Scavenger Receptor Class B Type I

Angiotensin II Promotes Selective Uptake of High Density Lipoprotein Cholesterol Esters in Bovine Adrenal Glomerulosa and Human Adrenocortical Carcinoma Cells Through Induction of Scavenger Receptor Class B Type I

Lipoproteins Regulate Expression of the Steroidogenic Acute Regulatory Protein (StAR) in Mouse Adrenocortical Cells

Evaluation of the molecular response of corpora lutea to manganese–amino acid complex supplementation in gilts

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