scholarly journals Regulation of cholesterol biosynthesis in cultured cells by probable natural precursor sterols.

1980 ◽  
Vol 255 (2) ◽  
pp. 395-400 ◽  
Author(s):  
G.F. Gibbons ◽  
C.R. Pullinger ◽  
H.W. Chen ◽  
W.K. Cavenee ◽  
A.A. Kandutsch
Keyword(s):  
Cultured Cells ◽  
Cholesterol Biosynthesis ◽  
Natural Precursor

TAMI-62. METHIONINE METABOLISM CLOSELY RELATED WITH SELF-RENEW, PLURIPOTENCY AND CELL DEATH IN GICS THROUGH MODIFICATION OF CHOLESTEROL BIOSYNTHESIS, RIBOSOMAL RNA AND AUTOPHAGY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi211-vi211
Author(s):  
Kiyotaka Yokogami ◽  
Hideo Takeshima
Keyword(s):  
Stem Cells ◽  
Cell Death ◽  
Ribosomal Rna ◽  
Cell Activation ◽  
Cultured Cells ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Dna Demethylation ◽  
Methionine Metabolism ◽  
Starting Point

Abstract Glioma initiating cells (GICs) are the source of glioma cells that have the ability to self-renew and pluripotency, which are treatment-resistant, starting point for relapse and eventual death despite multimodality therapy. Since high accumulation is observed in 11cMet-PET at the time of recurrence, it is important to understand the mechanism of tumor cell activation caused by the reorganization of methionine metabolism. We cultured cells in methionine-deprived culture medium and performed a comprehensive analysis, and found that methionine depletion markedly decreased proliferation and increasing cell death of GICs. Decreased SAM, which is synthesized intracellularly catalyzed by methionine adenosyltransferase (MAT) using methionine, triggered the following: (i) global DNA demethylation, (ii) hyper-methylation of signaling pathways regulating pluripotentcy of stem cells, (iii) decreased expression of the core-genes and pluripotent marker of stem cells, (iv) decreased cholesterol synthesis and increased excretion mainly through decreased SREBF2 and FOXM1, (v) down-regulation of the large subunit of ribosomal protein configured 28S and ACA43, snoRNA guiding the pseudouridylation of 28S ribosomal RNA, which has crucial role for translation and (vi) possible connection between methionine metabolism and pluripotency, protein synthesis through cholesterol metabolism: SREBF2-FOXM1 and ACA43 axis, respectively. (vii) Disruption of autophagy by insufficient formation of macroautophagosomes. In conclusion, methionine metabolism closely related with self-renew, pluripotency and cell death in GICs through modification of cholesterol biosynthesis, ribosomal RNA and autophagy.

scholarly journals Progesterone Inhibits Cholesterol Biosynthesis in Cultured Cells

1996 ◽  
Vol 271 (5) ◽  
pp. 2627-2633 ◽  
Author(s):  
James E. Metherall ◽  
Kathy Waugh ◽  
Huijuan Li
Keyword(s):  
Cultured Cells ◽  
Cholesterol Biosynthesis

Effect of YM 9429, a potent teratogen, on cholesterol biosynthesis in cultured cells and rat liver microsomes

Steroids ◽  
1996 ◽  
Vol 61 (9) ◽  
pp. 544-548 ◽  
Author(s):  
Akira Honda ◽  
G.Stephen Tint ◽  
Sarah Shefer ◽  
Ashok K. Batta ◽  
Megumi Honda ◽  
...  
Keyword(s):  
Rat Liver ◽  
Cultured Cells ◽  
Cholesterol Biosynthesis ◽  
Liver Microsomes ◽  
Rat Liver Microsomes

scholarly journals The Compound U18666A Inhibits the Intoxication of Cells by Clostridioides difficile Toxins TcdA and TcdB

2021 ◽  
Vol 12 ◽  
Author(s):  
Panagiotis Papatheodorou ◽  
Selina Kindig ◽  
Adriana Badilla-Lobo ◽  
Stephan Fischer ◽  
Ebru Durgun ◽  
...  
Keyword(s):  
Mode Of Action ◽  
Intracellular Transport ◽  
Cultured Cells ◽  
Clinical Symptoms ◽  
Regulatory Element ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Content ◽  
Host Cells ◽  
Membrane Cholesterol ◽  
Clostridioides Difficile

The intestinal pathogen Clostridioides (C.) difficile is a major cause of diarrhea both in hospitals and outpatient in industrialized countries. This bacterium produces two large exotoxins, toxin A (TcdA) and toxin B (TcdB), which are directly responsible for the onset of clinical symptoms of C. difficile-associated diseases (CDADs), such as antibiotics-associated diarrhea and the severe, life-threatening pseudomembranous colitis. Both toxins are multidomain proteins and taken up into host eukaryotic cells via receptor-mediated endocytosis. Within the cell, TcdA and TcdB inactivate Rho and/or Ras protein family members by glucosylation, which eventually results in cell death. The cytotoxic mode of action of the toxins is the main reason for the disease. Thus, compounds capable of inhibiting the cellular uptake and/or mode-of-action of both toxins are of high therapeutic interest. Recently, we found that the sterol regulatory element-binding protein 2 (SREBP-2) pathway, which regulates cholesterol content in membranes, is crucial for the intoxication of cells by TcdA and TcdB. Furthermore, it has been shown that membrane cholesterol is required for TcdA- as well as TcdB-mediated pore formation in endosomal membranes, which is a key step during the translocation of the glucosyltransferase domain of both toxins from endocytic vesicles into the cytosol of host cells. In the current study, we demonstrate that intoxication by TcdA and TcdB is diminished in cultured cells preincubated with the compound U18666A, an established inhibitor of cholesterol biosynthesis and/or intracellular transport. U18666A-pretreated cells were also less sensitive against TcdA and TcdB variants from the epidemic NAP1/027 C. difficile strain. Our study corroborates the crucial role of membrane cholesterol for cell entry of TcdA and TcdB, thus providing a valuable basis for the development of novel antitoxin strategies in the context of CDADs.

Impaired plasmalogen synthesis dysregulates liver X receptor-dependent transcription in cerebellum

2019 ◽  
Vol 166 (4) ◽  
pp. 353-361 ◽  
Author(s):  
Masanori Honsho ◽  
Fabian Dorninger ◽  
Yuichi Abe ◽  
Daiki Setoyama ◽  
Ryohei Ohgi ◽  
...  
Keyword(s):  
Cultured Cells ◽  
Cholesterol Biosynthesis ◽  
Wild Type Mouse ◽  
Fatty Acyl ◽  
Cholesterol Homeostasis ◽  
Squalene Epoxidase ◽  
Peroxisomal Membrane ◽  
X Receptors ◽  
The Stability ◽  
Coa Reductase

Abstract Synthesis of ethanolamine plasmalogen (PlsEtn) is regulated by modulating the stability of fatty acyl-CoA reductase 1 (Far1) on peroxisomal membrane, a rate-limiting enzyme in plasmalogen synthesis. Dysregulation of plasmalogen homeostasis impairs cholesterol biosynthesis in cultured cells by altering the stability of squalene epoxidase (SQLE). However, regulation of PlsEtn synthesis and physiological consequences of plasmalogen homeostasis in tissues remain unknown. In the present study, we found that the protein but not the transcription level of Far1 in the cerebellum of the Pex14 mutant mouse expressing Pex14p lacking its C-terminal region (Pex14ΔC/ΔC) is higher than that from wild-type mouse, suggesting that Far1 is stabilized by the lowered level of PlsEtn. The protein level of SQLE was increased, whereas the transcriptional activity of the liver X receptors (LXRs), ligand-activated transcription factors of the nuclear receptor superfamily, is lowered in the cerebellum of Pex14ΔC/ΔC and the mice deficient in dihydroxyacetonephosphate acyltransferase, the initial enzyme for the synthesis of PlsEtn. These results suggest that the reduction of plasmalogens in the cerebellum more likely compromises the cholesterol homeostasis, thereby reducing the transcriptional activities of LXRs, master regulators of cholesterol homeostasis.

scholarly journals Flux analysis of cholesterol biosynthesis in vivo reveals multiple tissue and cell-type specific pathways

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Matthew A Mitsche ◽  
Jeffrey G McDonald ◽  
Helen H Hobbs ◽  
Jonathan C Cohen
Keyword(s):  
Tissue Specificity ◽  
Isotope Labeling ◽  
Cultured Cells ◽  
Cholesterol Biosynthesis ◽  
Flux Analysis ◽  
Preputial Gland ◽  
Cell Type ◽  
Isotopomer Analysis ◽  
Cell Type Specific

Two parallel pathways produce cholesterol: the Bloch and Kandutsch-Russell pathways. Here we used stable isotope labeling and isotopomer analysis to trace sterol flux through the two pathways in mice. Surprisingly, no tissue used the canonical K–R pathway. Rather, a hybrid pathway was identified that we call the modified K–R (MK–R) pathway. Proportional flux through the Bloch pathway varied from 8% in preputial gland to 97% in testes, and the tissue-specificity observed in vivo was retained in cultured cells. The distribution of sterol isotopomers in plasma mirrored that of liver. Sterol depletion in cultured cells increased flux through the Bloch pathway, whereas overexpression of 24-dehydrocholesterol reductase (DHCR24) enhanced usage of the MK–R pathway. Thus, relative use of the Bloch and MK–R pathways is highly variable, tissue-specific, flux dependent, and epigenetically fixed. Maintenance of two interdigitated pathways permits production of diverse bioactive sterols that can be regulated independently of cholesterol.

scholarly journals Inhibition of 3-hydroxy-3-methylglutaryl-CoA synthase and cholesterol biosynthesis by β-lactone inhibitors and binding of these inhibitors to the enzyme

1993 ◽  
Vol 289 (3) ◽  
pp. 889-895 ◽  
Author(s):  
M D Greenspan ◽  
H G Bull ◽  
J B Yudkovitz ◽  
D P Hanf ◽  
A W Alberts
Keyword(s):  
Rat Liver ◽  
Cultured Cells ◽  
Enzyme Inhibitor ◽  
Cholesterol Biosynthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Inhibitor Complex ◽  
Sds Page ◽  
G2 Cells

The beta-lactones L-659,699 [(E,E)-11-[3-(hydroxymethyl)-4-oxo-2- oxetanyl]-3,5,7-trimethyl-2,4-undecadienoic acid) and its radioactive derivative 3H-L-668,411 (the 2,3-ditritiated methyl ester of L-659,699) inhibited a partially purified preparation of rat liver cytosolic 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase with an IC50 of 0.1 microM. These compounds were also found to inhibit the incorporation of [14C]acetate into sterols in cultured Hep G2 cells with an IC50 of 3 microM. New kinetic evidence indicated that inhibition of the isolated enzyme was irreversible. In contrast, sterol biosynthesis in cultured Hep G2 cells was rapidly restored upon removal of the compound from the medium of inhibited cultures, suggesting reversibility of inhibition in the cells. Radioactivity was found to be associated with a single cytoplasmic protein by SDS/PAGE of the cytoplasm of Hep G2 cells after incubation of the cells with the inhibitor 3H-L-668,411. This protein was identified as cytoplasmic HMG-CoA synthase. Binding of the radioactive compound to the enzyme was decreased with time if the radioactive inhibitor was removed from the medium. Exposure of a gel containing the radioactive enzyme-inhibitor complex to neutral hydroxylamine also resulted in a loss of radioactivity from the gel. The purified rat liver enzyme reacted with the 3H-ligand to form a stable enzyme-inhibitor complex which could be isolated by h.p.l.c. Radioactivity was also subsequently lost from this complex when it was incubated with neutral hydroxylamine. Incorporation of [14C]acetate into cholesterol in mouse liver was inhibited in a reversible manner after oral administration of the beta-lactone inhibitor. These studies, as well as the kinetic evidence presented, suggest that the beta-lactone inhibitors acylate HMG-CoA synthase in a reaction which appears to be irreversible in vitro, but is easily reversed in cultured cells and in animals.

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