Cholesterol versus other sterols: How do they compare as physiological regulators of cholesterol homeostasis?

Brown, Andrew

doi:10.1002/ejlt.201100295

Cited by 3 publications

(3 citation statements)

References 50 publications

(62 reference statements)

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“…Sterols are inhomogeneously distributed among the membranes of eukaryotic cells by unknown mechanisms [1] – [5] . PMs (plasma membranes) are characteristically sterol rich; in some animal cells, they contain ∼80% of the total unesterified cell cholesterol at a CH/PL (cholesterol/phospholipid) mole ratio of 0.7–0.8 [6] – [8] .…”

Section: Introductionmentioning

confidence: 99%

Essentially All Excess Fibroblast Cholesterol Moves from Plasma Membranes to Intracellular Compartments

2014

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It has been shown that modestly increasing plasma membrane cholesterol beyond its physiological set point greatly increases the endoplasmic reticulum and mitochondrial pools, thereby eliciting manifold feedback responses that return cell cholesterol to its resting state. The question arises whether this homeostatic mechanism reflects the targeting of cell surface cholesterol to specific intracellular sites or its general equilibration among the organelles. We now show that human fibroblast cholesterol can be increased as much as two-fold from 2-hydroxypropyl-β-cyclodextrin without changing the size of the cell surface pool. Rather, essentially all of the added cholesterol disperses rapidly among cytoplasmic membranes, increasing their overall cholesterol content by as much as five-fold. We conclude that the level of plasma membrane cholesterol is normally at capacity and that even small increments above this physiological set point redistribute essentially entirely to intracellular membranes, perhaps down their chemical activity gradients.

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Section: Introductionmentioning

confidence: 99%

Essentially All Excess Fibroblast Cholesterol Moves from Plasma Membranes to Intracellular Compartments

2014

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“…It is commonly known that OS show diverse biological activities including cytotoxic (Zmijewski et al, 2009;Carvalho et al, 2011), pro-apoptotic, and pro-inflammatory events (Hwang, 1991;Olkkonen and Hynynen, 2009). In addition, OS, have been implicated in numerous biochemical (Schroepfer, 2000;Bielska et al, 2012;Brown 2012) and pharmacological actions with special emphasis on cellularity (Larsson, et al, 2006;. Recently, it was established that furan fatty acids and Cholesta-3,5-diene (S5, compound #9 in this study), a component of catfish lipids was found to recruit neutrophils and fibroblasts to promote wound healing (Al-Hassan et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Oxysterols in catfish skin secretions (Arius bilineatus, Val.) exhibit anti-cancer properties

et al. 2022

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The edible catfish Arius bilineatus, (Valenciennes) elaborates a proteinaceous gel-like material through its epidermis when threatened or injured. Our on-going studies on this gel have shown it to be a complex mixture of several biologically active molecules. Anti-cancer studies on lipid fractions isolated from the gel-like materials showed them to be active against several cancer cell lines. This prompted us to investigate further the lipid composition of the catfish epidermal gel secretions (EGS). Analysis of the lipid fraction of EGS resulted in identification of 12 oxysterols including cholesterol and 2 deoxygenated steroids i.e., 7α-hydroxy cholesterol, 7β-hydroxycholesterol, 5,6 epoxycholesterol, 3β-hydroxycholest-5-ene-7-one and cholesta-3,5-dien-7-one. Progesterone, cholest-3,5-diene, cholesta-2,4-diene, cholest-3,5,6-triol and 4-cholesten-3-one were found as minor components, and were identified through their MS, 1HNMR and FTIR spectral data and were compared with those of the standards. Cholest-3,6-dione, cholesta-4,6-diene-3-one, cholesta-2,4-diene, and cholesta-5,20(22)-dien-3-ol were found only in trace amounts and were identified by GC/MS/MS spectral data. Since cholesterol is the major component of EGS, the identified oxysterols (OS) are presumably cholesterol oxidation products. Many of the identified OS are known important biological molecules that play vital physiological role in the producer and recipient organisms. We report herein the effects of these sterols on three human cancer cell lines in vitro, i.e., K-562 (CML cell line), MDA MB-231 (estrogen positive breast cancer cell line) and MCF-7 (estrogen negative breast cancer cell line). Interestingly significant (p < 0.05) dose differences were observed between tested OS on cell types used. The presence of these sterols in EGS may help explain some aspects of the physiological activities of fraction B (FB) prepared from EGS, such as enhanced wound and diabetic ulcer healing, anti-inflammatory action and cytotoxic activities reported in our previous studies. The anti-proliferative actions of some of these oxysterols especially the cholesterol 3,5,6-triol (#5) as established on selected cancer cell lines in this study support our previous studies and make them candidates for research for human application.

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“…In this issue, A. Brown provides us with an updated and critical overview on the topic, also proposing the challenges we are going to face in the future 1.…”

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confidence: 99%

The complex world of sterols: Many threads find their way through cells

Fabiani

2012

Euro J Lipid Sci & Tech

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Cholesterol versus other sterols: How do they compare as physiological regulators of cholesterol homeostasis?

Cited by 3 publications

References 50 publications

Essentially All Excess Fibroblast Cholesterol Moves from Plasma Membranes to Intracellular Compartments

Essentially All Excess Fibroblast Cholesterol Moves from Plasma Membranes to Intracellular Compartments

Oxysterols in catfish skin secretions (Arius bilineatus, Val.) exhibit anti-cancer properties

The complex world of sterols: Many threads find their way through cells

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