scholarly journals Hypercholesterolemia and 27-Hydroxycholesterol Increase S100A8 and RAGE Expression in the Brain: a Link Between Cholesterol, Alarmins, and Neurodegeneration

2021 ◽  
Author(s):  
Raúl Loera-Valencia ◽  
Muhammad-Al-Mustafa Ismail ◽  
Julen Goikolea ◽  
Maria Lodeiro ◽  
Laura Mateos ◽  
...  
Keyword(s):  
Cholesterol Metabolism ◽  
Primary Cultures ◽  
Transgenic Mouse Model ◽  
Intraventricular Injection ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
High Fat ◽  
The Brain ◽  
Rage Expression

AbstractAlterations in cholesterol metabolism in the brain have a major role in the physiology of Alzheimer’s disease (AD). Oxysterols are cholesterol metabolites with multiple implications in memory functions and in neurodegeneration. Previous studies have shown detrimental effects of cholesterol metabolites in neurons, but its effect in glial cells is unknown. We used a high-fat/high-cholesterol diet in mice to study the effects of hypercholesterolemia over the alarmin S100A8 cascade in the hippocampus. Using CYP27Tg, a transgenic mouse model, we show that the hypercholesterolemia influence on the brain is mediated by the excess of 27-hydroxycholesterol (27-OH), a cholesterol metabolite. We also employed an acute model of 27-OH intraventricular injection in the brain to study RAGE and S100A8 response. We used primary cultures of neurons and astrocytes to study the effect of high levels of 27-OH over the S100A8 alarmin cascade. We report that a high-fat/high-cholesterol diet leads to an increase in S100A8 production in the brain. In CYP27Tg, we report an increase of S100A8 and its receptor RAGE in the hippocampus under elevated 27-OH in the brain. Using siRNA, we found that 27-OH upregulation of RAGE in astrocytes and neurons is mediated by the nuclear receptor RXRγ. Silencing RXRγ in neurons prevented 27-OH-mediated upregulation of RAGE. These results show that S100A8 alarmin and RAGE respond to high levels of 27-OH in the brain in both neurons and astrocytes through RXRγ. Our study supports the notion that 27-OH mediates detrimental effects of hypercholesterolemia to the brain via alarmin signaling.

Pharmacological activation of LXR in utero directly influences ABC transporter expression and function in mice but does not affect adult cholesterol metabolism

2008 ◽  
Vol 295 (6) ◽  
pp. E1341-E1348 ◽  
Author(s):  
E. M. E. van Straten ◽  
N. C. A. Huijkman ◽  
J. F. W. Baller ◽  
F. Kuipers ◽  
T. Plösch
Keyword(s):  
Fetal Development ◽  
Cholesterol Metabolism ◽  
In Utero ◽  
Cholesterol Homeostasis ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
High Fat ◽  
Hepatic Expression ◽  
Cholesterol Levels

Cholesterol is critical for several cellular functions and essential for normal fetal development. Therefore, its metabolism is tightly controlled during all life stages. The liver X receptors-α (LXRα; NR1H3) and -β (LXRβ; NR1H2) are nuclear receptors that are of key relevance in coordinating cholesterol and fatty acid metabolism. The aim of this study was to elucidate whether fetal cholesterol metabolism can be influenced in utero via pharmacological activation of LXR and whether this would have long-term effects on cholesterol homeostasis. Administration of the LXR agonist T0901317 to pregnant mice via their diet (0.015% wt/wt) led to induced fetal hepatic expression levels of the cholesterol transporter genes Abcg5/g8 and Abca1, higher plasma cholesterol levels, and lower hepatic cholesterol levels compared with controls. These profound changes during fetal development did not affect cholesterol metabolism in adulthood nor did they influence coping with a high-fat/high-cholesterol diet. This study shows that the LXR system is functional in fetal mice and susceptible to pharmacological activation. Despite massive changes in fetal cholesterol metabolism, regulatory mechanisms involved in cholesterol metabolism return to a “normal” state in offspring and allow coping with a high-fat/high-cholesterol diet.

scholarly journals High-Cholesterol Diet Decreases the Level of Phosphatidylinositol 4,5-Bisphosphate by Enhancing the Expression of Phospholipase C (PLCβ1) in Rat Brain

2020 ◽  
Vol 21 (3) ◽  
pp. 1161 ◽  
Author(s):  
Yoon Sun Chun ◽  
Sungkwon Chung
Keyword(s):  
Neurodegenerative Diseases ◽  
Rat Brain ◽  
Phospholipase C ◽  
Cultured Cells ◽  
Cell Interaction ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
Amyloid Aβ ◽  
The Brain

Cholesterol is a critical component of eukaryotic membranes, where it contributes to regulating transmembrane signaling, cell–cell interaction, and ion transport. Dysregulation of cholesterol levels in the brain may induce neurodegenerative diseases, such as Alzheimer’s disease, Parkinson disease, and Huntington disease. We previously reported that augmenting membrane cholesterol level regulates ion channels by decreasing the level of phosphatidylinositol 4,5-bisphosphate (PIP2), which is closely related to β-amyloid (Aβ) production. In addition, cholesterol enrichment decreased PIP2 levels by increasing the expression of the β1 isoform of phospholipase C (PLC) in cultured cells. In this study, we examined the effect of a high-cholesterol diet on phospholipase C (PLCβ1) expression and PIP2 levels in rat brain. PIP2 levels were decreased in the cerebral cortex in rats on a high-cholesterol diet. Levels of PLCβ1 expression correlated with PIP2 levels. However, cholesterol and PIP2 levels were not correlated, suggesting that PIP2 level is regulated by cholesterol via PLCβ1 expression in the brain. Thus, there exists cross talk between cholesterol and PIP2 that could contribute to the pathogenesis of neurodegenerative diseases.

Sub-chronic microcystin-LR renal toxicity in rats fed a high fat/high cholesterol diet

Chemosphere ◽  
2020 ◽  
pp. 128773
Author(s):  
Tarana Arman ◽  
Katherine D. Lynch ◽  
Michael Goedken ◽  
John D. Clarke
Keyword(s):  
Renal Toxicity ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
High Fat

scholarly journals Interleukin-18 predicts atherosclerosis progression in SIV-infected and uninfected rhesus monkeys (Macaca mulatta) on a high-fat/high-cholesterol diet

2009 ◽  
Vol 89 (6) ◽  
pp. 657-667 ◽  
Author(s):  
Jennifer H Yearley ◽  
Dongling Xia ◽  
Christine B Pearson ◽  
Angela Carville ◽  
Richard P Shannon ◽  
...  
Keyword(s):  
Macaca Mulatta ◽  
Rhesus Monkeys ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
Interleukin 18 ◽  
High Cholesterol ◽  
High Fat ◽  
Atherosclerosis Progression

Abstract 130: Hypercholesterolemia Suppresses Carotid Artery Endothelial NOS3 Expression via Epigenetic Mechanisms

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Alex Sotolongo ◽  
Yi-Zhou Jiang ◽  
John Karanian ◽  
William Pritchard ◽  
Peter Davies
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Endothelial Cells ◽  
Dna Methyltransferase ◽  
Control Group ◽  
High Cholesterol Diet ◽  
Cholesterol Diet ◽  
High Cholesterol ◽  
High Fat

Objective: One of the first clinically detectable changes in the vasculature during atherogenesis is the accumulation of cholesterol within the vessel wall. Hypercholesterolemia is characterized by dysfunctional endothelial-dependent vessel relaxation and impaired NOS3 function. Since DNA methylation at gene promoter regions strongly suppresses gene expression, we postulated that high-fat/high-cholesterol diet suppresses endothelial NOS3 through promoter DNA methylation. Methods: Domestic male pigs were fed control diet (CD) or isocaloric high fat and high cholesterol diet (HC; 12% fat and 1.5% cholesterol) for 2, 4, 8 or 12 weeks prior to tissue collection. Furthermore, to determine the effects of risk factor withdrawal, an additional group of swine received HC for 12 weeks and then CD for 8 weeks; a control group received HC continuously for 20 weeks. Endothelial cells were harvested from common carotid aorta. In parallel in vitro studies, cultured human aortic endothelial cells (HAEC) were treated with human LDL, GW3956 (LXR agonist) and RG108 (DNA methyltransferase [DNMT] inhibitor). In cells from both sources, DNA methylation at the NOS3 promoter was measured using methylation specific pyro sequencing, and endothelial gene expression was measured using RT PCR. Results: HC diet increased plasma cholesterol level from 75 mg/dl on CD to a plateau of about 540 mg/dl within 2 weeks. Endothelial NOS3 expression was significantly reduced (71±9 % of CD) after 4 weeks of HC, a level sustained at subsequent time points. Withdrawal of HC for 8 weeks did not recover NOS3 expression. After 12-week HC, the NOS3 promoter was hypermethylated. Withdrawal of HC did not reverse NOS3 promoter methylation. In vitro treatment of HAEC with human LDL (200 mg/dl total cholesterol) or GW3956 (5μM) suppressed NOS3 mRNA to 50% and 30% respectively, suggesting that LXR/RXR is involved in suppression of NOS3. Nitric oxide production was consistently suppressed by GW3959. Both could be reversed through inhibition of DNMTs by RG108. Conclusions: DNA methylation and LXR/RXR pathway can mediate the HC-suppression of endothelial NOS3. The study identifies novel pharmaceutical targets in treating endothelial dysfunction. Crosstalk between these pathways is under investigation.

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