Rat adrenal uptake and metabolism of high density lipoprotein cholesteryl ester

Gwynne, John T.; Mahaffee, D D

doi:10.1016/s0021-9258(18)83161-1

Cited by 121 publications

(16 citation statements)

References 64 publications

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“…pacity, hormone-inducible cholesterol delivery system for cells that require exogeneous cholesterol for product synthesis (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). In the selective uptake process, lipoproteins [e.g., high density (HDL) or low density (LDL) lipoproteins] that bind to the surface of cells are not directly interiorized by the cells [as they are in the classical endocytic B/E (LDL) receptor pathway (18)], but the lipoproteins selectively release their CE content to the target cells; i.e., CEs enter the target cells unaccompanied by the ligand apoproteins (3,7,9,12,15,(19)(20)(21)(22).…”

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confidence: 99%

Simultaneous induction of an HDL receptor protein (SR-BI) and the selective uptake of HDL-cholesteryl esters in a physiologically relevant steroidogenic cell model

Azhar

Nomoto

Leers-Sucheta

et al. 1998

Journal of Lipid Research

109

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This study addresses the question of whether the level of expression of SR-BI (an HDL receptor) is linked to the expression of selective lipoprotein-cholesteryl ester delivery in a steroidogenic cell model. Rat ovarian granulosa cells are physiologically normal cells which show no selective uptake of HDL-cholesteryl esters and no progestin production until luteinized by trophic hormones or adenylate cyclase stimulators, after which expression of the selective cholesterol pathway and production of steroid hormone is dramatically up-regulated. The current study demonstrates that at every cell stage studied, the protein content and level of expression of SR-BI mRNA are linked to changes that occur in HDL-cholesteryl ester uptake; i.e., SR-BI is not present in basal (non-luteinized) cells, develops slowly (from 6-9 h) after hormone treatment, increases robustly from 9-48 h after stimulation, and remains high after incubation with HDL. In contrast, another structural protein, caveolin, did not follow this patter n; caveolin expression showed an inverse relationship to selective cholesteryl ester uptake, and was most prominent in basal cells and least prominent in luteinized, HDL-incubated cells. Morphologically, SR-BI appears to be associated with cell surface sites showing high levels of cholesteryl ester uptake (after luteinization and/or incubation with HDL labeled with fluorescent cholesteryl esters), and at the electron microscope level, SR-BI is most clearly associated with microvillar regions on the cell surface which also bind HDL-labeled with colloidal gold. Thus, induction of the SR-BI receptor system and induction of the HDL-selective cholesterol uptake pathway in rat granulosa cells appear to be linked morphologically, biochemically, and functionally.-Azhar, S., A. Nomoto, S. Leers-Sucheta, and E. Reaven. Simultaneous induction of an HDL receptor protein (SR-BI) and the selective uptake of HDL-cholesteryl esters in a physiologically relevant steroidogenic cell model.

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confidence: 99%

Simultaneous induction of an HDL receptor protein (SR-BI) and the selective uptake of HDL-cholesteryl esters in a physiologically relevant steroidogenic cell model

Azhar

Nomoto

Leers-Sucheta

et al. 1998

Journal of Lipid Research

109

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“…For example, SR-BI was required for uptake of CE from HDL3 in the breast cancer cell line HBL-100 [70]. SR-BI was also needed for selective CE uptake providing cholesterol as precursor for production of steroid hormones and for storage in intracellular CE droplets of Leydig cells from rat testis [71]. HDL also inhibited the activation of sterol regulatory element-binding protein-1 (SREBP-1), which resulted in the transcription of β-Hydroxy β-methylglutaryl-CoA (HMG-CoA) reductase, a key enzyme of cholesterol biosynthesis.…”

Section: Sr-bi and Cholesterol Metabolism In Cancermentioning

confidence: 99%

SR-BI as a target of natural products and its significance in cancer

Wang

Huang

Gui

et al. 2022

Seminars in Cancer Biology

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Scavenger receptor class B type I (SR-BI) protein is an integral membrane glycoprotein. SR-BI is emerging as a multifunctional protein, which regulates autophagy, efferocytosis, cell survival and inflammation. It is well known that SR-BI plays a critical role in lipoprotein metabolism by mediating cholesteryl esters selective uptake and the bi-directional flux of free cholesterol. Recently, SR-BI has also been identified as a potential marker for cancer diagnosis, prognosis, or even a treatment target. Natural products are a promising source for the discovery of new drug leads. Multiple natural products were identified to regulate SR-BI protein expression. There are still a number of challenges in modulating SR-BI expression in cancer and in using natural products for modulation of such protein expression. In this review, our purpose is to discuss the relationship between SR-BI protein and cancer, and the molecular mechanisms regulating SR-BI expression, as well as to provide an overview of natural products that regulate SR-BI expression.

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“…HDL 3 apolipoproteins were then iodinated with iodine monochloride (13) to a specific radioactivity of 400-600 cpm/ng protein. 1 ␣ ,2 ␣ (n) [ 3 H]cholesteryl-oleate was then incorporated into 125 Ilabeled HDL 3 as described previously (14). The specific radioactivity of [ 3 H]cholesterol ester in the dually labeled particles ranged from 32 -35 dpm/ng cholesterol.…”

Section: Isolation and Labeling Of Lipoproteinsmentioning

confidence: 99%

17β-Estradiol promotes the up-regulation of SR-BII in HepG2 cells and in rat livers

Graf

Roswell

Smart

2001

Journal of Lipid Research

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The scavenger receptor class B type I (SR-BI) binds to HDL and mediates the selective uptake of cholesterol esters from HDL to cells. SR-BII is an alternatively spliced product of the SR-BI gene that only differs in the C-terminal cytoplasmic domain. Previous studies with male mice demonstrated that SR-BII comprises about 12% of the total SR-BI/SR-BII present in liver. In the current studies we used a liver cell line, HepG2, and a rat estrogen replacement model to examine the effects of estrogen on the expression of SR-BII. HepG2 cells express SR-BI but not SR-BII. SR-BI/SR-BII-blocking antibodies demonstrated that HepG2 cells selectively internalize cholesterol esters in a SR-BI-dependent manner. Incubation of HepG2 cells with 10 pM of 17␤-estradiol for 12 h eliminated the expression of SR-BI and promoted the up-regulation of SR-BII. Radiolabeled HDL-binding studies demonstrated that 17 ␤estradiol increased the number of HDL binding sites by 3-fold in HepG2 cells. However, 17 ␤ -estradiol-treated cell internalized approximately 25% less cholesterol ester than vehicle-onlytreated cells. The livers obtained from male rats and ovariectomized female rats contained SR-BI and a small amount of SR-BII. In contrast, the livers obtained from intact female rats and ovariectomized female rats receiving estrogen replacement contained SR-BII and a small amount of SR-BI. The amount of SR-BI and SR-BII in adrenal tissue was not affected by any of the experimental treatments. We conclude that estrogen up-regulates SR-BII in HepG2 cells and rat liver. -Graf G. A., K. L. Roswell, and E. J. Smart. 17 ␤ -Estradiol promotes the up-regulation of SR-BII in HepG2 cells and in rat livers.

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Rat adrenal uptake and metabolism of high density lipoprotein cholesteryl ester

Cited by 121 publications

References 64 publications

Simultaneous induction of an HDL receptor protein (SR-BI) and the selective uptake of HDL-cholesteryl esters in a physiologically relevant steroidogenic cell model

Simultaneous induction of an HDL receptor protein (SR-BI) and the selective uptake of HDL-cholesteryl esters in a physiologically relevant steroidogenic cell model

SR-BI as a target of natural products and its significance in cancer

17β-Estradiol promotes the up-regulation of SR-BII in HepG2 cells and in rat livers

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