scholarly journals Diverse Immunoregulatory Roles of Oxysterols—The Oxidized Cholesterol Metabolites

Metabolites ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 384
Author(s):  
Chloe Choi ◽  
David K. Finlay
Keyword(s):  
Immune Responses ◽  
Cholesterol Metabolism ◽  
Immune Dysregulation ◽  
Review Article ◽  
Cholesterol Homeostasis ◽  
Metabolic Processes ◽  
Control Of Gene Expression ◽  
Cellular Processes ◽  
Oxidized Cholesterol ◽  
Expression Signal

Intermediates of both cholesterol synthesis and cholesterol metabolism can have diverse roles in the control of cellular processes that go beyond the control of cholesterol homeostasis. For example, oxidized forms of cholesterol, called oxysterols have functions ranging from the control of gene expression, signal transduction and cell migration. This is of particular interest in the context of immunology and immunometabolism where we now know that metabolic processes are key towards shaping the nature of immune responses. Equally, aberrant metabolic processes including altered cholesterol homeostasis contribute to immune dysregulation and dysfunction in pathological situations. This review article brings together our current understanding of how oxysterols affect the control of immune responses in diverse immunological settings.

scholarly journals Multifaceted Functions of CH25H and 25HC to Modulate the Lipid Metabolism, Immune Responses, and Broadly Antiviral Activities

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 727 ◽  
Author(s):  
Jin Zhao ◽  
Jiaoshan Chen ◽  
Minchao Li ◽  
Musha Chen ◽  
Caijun Sun
Keyword(s):  
Lipid Metabolism ◽  
Infectious Diseases ◽  
Immune Responses ◽  
Cholesterol Metabolism ◽  
Rift Valley Fever Virus ◽  
Antiviral Drug ◽  
Emerging Infectious Diseases ◽  
Cholesterol Homeostasis ◽  
Global Public Health ◽  
Antiviral Activities

With the frequent outbreaks of emerging infectious diseases in recent years, an effective broad-spectrum antiviral drug is becoming an urgent need for global public health. Cholesterol-25-hydroxylase (CH25H) and its enzymatic products 25-hydroxycholesterol (25HC), a well-known oxysterol that regulates lipid metabolism, have been reported to play multiple functions in modulating cholesterol homeostasis, inflammation, and immune responses. CH25H and 25HC were recently identified as exerting broadly antiviral activities, including upon a variety of highly pathogenic viruses such as human immunodeficiency virus (HIV), Ebola virus (EBOV), Nipah virus (NiV), Rift Valley fever virus (RVFV), and Zika virus (ZIKV). The underlying mechanisms for its antiviral activities are being extensively investigated but have not yet been fully clarified. In this study, we summarized the current findings on how CH25H and 25HC play multiple roles to modulate cholesterol metabolism, inflammation, immunity, and antiviral infections. Overall, 25HC should be further studied as a potential therapeutic agent to control emerging infectious diseases in the future.

scholarly journals Abnormal brain cholesterol homeostasis in Alzheimer’s disease—a targeted metabolomic and transcriptomic study

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vijay R. Varma ◽  
H. Büşra Lüleci ◽  
Anup M. Oommen ◽  
Sudhir Varma ◽  
Chad T. Blackshear ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Tissue ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cholesterol Homeostasis ◽  
Transcriptomic Data ◽  
Brain Cholesterol ◽  
Cholesterol Levels

AbstractThe role of brain cholesterol metabolism in Alzheimer’s disease (AD) remains unclear. Peripheral and brain cholesterol levels are largely independent due to the impermeability of the blood brain barrier (BBB), highlighting the importance of studying the role of brain cholesterol homeostasis in AD. We first tested whether metabolite markers of brain cholesterol biosynthesis and catabolism were altered in AD and associated with AD pathology using linear mixed-effects models in two brain autopsy samples from the Baltimore Longitudinal Study of Aging (BLSA) and the Religious Orders Study (ROS). We next tested whether genetic regulators of brain cholesterol biosynthesis and catabolism were altered in AD using the ANOVA test in publicly available brain tissue transcriptomic datasets. Finally, using regional brain transcriptomic data, we performed genome-scale metabolic network modeling to assess alterations in cholesterol biosynthesis and catabolism reactions in AD. We show that AD is associated with pervasive abnormalities in cholesterol biosynthesis and catabolism. Using transcriptomic data from Parkinson’s disease (PD) brain tissue samples, we found that gene expression alterations identified in AD were not observed in PD, suggesting that these changes may be specific to AD. Our results suggest that reduced de novo cholesterol biosynthesis may occur in response to impaired enzymatic cholesterol catabolism and efflux to maintain brain cholesterol levels in AD. This is accompanied by the accumulation of nonenzymatically generated cytotoxic oxysterols. Our results set the stage for experimental studies to address whether abnormalities in cholesterol metabolism are plausible therapeutic targets in AD.

scholarly journals Neurotrophins as Key Regulators of Cell Metabolism: Implications for Cholesterol Homeostasis

2021 ◽  
Vol 22 (11) ◽  
pp. 5692
Author(s):  
Mayra Colardo ◽  
Noemi Martella ◽  
Daniele Pensabene ◽  
Silvia Siteni ◽  
Sabrina Di Bartolomeo ◽  
...  
Keyword(s):  
Growth Factors ◽  
Cholesterol Metabolism ◽  
System Development ◽  
Cell Metabolism ◽  
Redox Balance ◽  
Nervous System Development ◽  
Cholesterol Homeostasis ◽  
Signaling Cascades ◽  
Target Cells ◽  
The Impact

Neurotrophins constitute a family of growth factors initially characterized as predominant mediators of nervous system development, neuronal survival, regeneration and plasticity. Their biological activity is promoted by the binding of two different types of receptors, leading to the generation of multiple and variegated signaling cascades in the target cells. Increasing evidence indicates that neurotrophins are also emerging as crucial regulators of metabolic processes in both neuronal and non-neuronal cells. In this context, it has been reported that neurotrophins affect redox balance, autophagy, glucose homeostasis and energy expenditure. Additionally, the trophic support provided by these secreted factors may involve the regulation of cholesterol metabolism. In this review, we examine the neurotrophins’ signaling pathways and their effects on metabolism by critically discussing the most up-to-date information. In particular, we gather experimental evidence demonstrating the impact of these growth factors on cholesterol metabolism.

scholarly journals The Impact of Anthocyanins and Iridoids on Transcription Factors Crucial for Lipid and Cholesterol Homeostasis

2021 ◽  
Vol 22 (11) ◽  
pp. 6074
Author(s):  
Maciej Danielewski ◽  
Agnieszka Matuszewska ◽  
Adam Szeląg ◽  
Tomasz Sozański
Keyword(s):  
Transcription Factors ◽  
Cholesterol Metabolism ◽  
Binding Protein ◽  
Regulatory Element ◽  
Cholesterol Homeostasis ◽  
Lipid Lowering ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Cell Functions ◽  
The Impact

Nutrition determines our health, both directly and indirectly. Consumed foods affect the functioning of individual organs as well as entire systems, e.g., the cardiovascular system. There are many different diets, but universal guidelines for proper nutrition are provided in the WHO healthy eating pyramid. According to the latest version, plant products should form the basis of our diet. Many groups of plant compounds with a beneficial effect on human health have been described. Such groups include anthocyanins and iridoids, for which it has been proven that their consumption may lead to, inter alia, antioxidant, cholesterol and lipid-lowering, anti-obesity and anti-diabetic effects. Transcription factors directly affect a number of parameters of cell functions and cellular metabolism. In the context of lipid and cholesterol metabolism, five particularly important transcription factors can be distinguished: liver X receptor (LXR), peroxisome proliferator-activated receptor-α (PPAR-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding protein α (C/EBPα) and sterol regulatory element-binding protein 1c (SREBP-1c). Both anthocyanins and iridoids may alter the expression of these transcription factors. The aim of this review is to collect and systematize knowledge about the impact of anthocyanins and iridoids on transcription factors crucial for lipid and cholesterol homeostasis.

scholarly journals Regulation of Bile Acid and Cholesterol Metabolism by PPARs

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Tiangang Li ◽  
John Y. L. Chiang
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Cholesterol Metabolism ◽  
Acid Synthesis ◽  
Bile Acid Synthesis ◽  
Cholesterol Homeostasis ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Major Pathway ◽  
Therapeutic Implications

Bile acids are amphipathic molecules synthesized from cholesterol in the liver. Bile acid synthesis is a major pathway for hepatic cholesterol catabolism. Bile acid synthesis generates bile flow which is important for biliary secretion of free cholesterol, endogenous metabolites, and xenobiotics. Bile acids are biological detergents that facilitate intestinal absorption of lipids and fat-soluble vitamins. Recent studies suggest that bile acids are important metabolic regulators of lipid, glucose, and energy homeostasis. Agonists of peroxisome proliferator-activated receptors (PPARα, PPARγ, PPARδ) regulate lipoprotein metabolism, fatty acid oxidation, glucose homeostasis and inflammation, and therefore are used as anti-diabetic drugs for treatment of dyslipidemia and insulin insistence. Recent studies have shown that activation of PPARαalters bile acid synthesis, conjugation, and transport, and also cholesterol synthesis, absorption and reverse cholesterol transport. This review will focus on the roles of PPARs in the regulation of pathways in bile acid and cholesterol homeostasis, and the therapeutic implications of using PPAR agonists for the treatment of metabolic syndrome.

scholarly journals Methotrexate in Atherogenesis and Cholesterol Metabolism

Cholesterol ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Eric Coomes ◽  
Edwin S. L. Chan ◽  
Allison B. Reiss
Keyword(s):  
Cardiovascular Risk ◽  
Cholesterol Metabolism ◽  
Cholesterol Homeostasis ◽  
Cholesterol Transport ◽  
Creb Activation ◽  
Inflammatory Conditions ◽  
Atp Binding Cassette Transporter ◽  
Cox 2 ◽  
Cellular Cholesterol Efflux ◽  
Disease Modifying Antirheumatic Drug

Methotrexate is a disease-modifying antirheumatic drug commonly used to treat inflammatory conditions such as rheumatoid arthritis which itself is linked to increased cardiovascular risk. Treatments that target inflammation may also impact the cardiovascular system. While methotrexate improves cardiovascular risk, inhibition of the cyclooxygenase (COX)-2 enzyme promotes atherosclerosis. These opposing cardiovascular influences may arise from differing effects on the expression of proteins involved in cholesterol homeostasis. These proteins, ATP-binding cassette transporter (ABC) A1 and cholesterol 27-hydroxylase, facilitate cellular cholesterol efflux and defend against cholesterol overload. Methotrexate upregulates expression of cholesterol 27-hydroxylase and ABCA1 via adenosine release, while COX-2 inhibition downregulates these proteins. Adenosine, acting through the A2A and A3 receptors, may upregulate proteins involved in reverse cholesterol transport by cAMP-PKA-CREB activation and STAT inhibition, respectively. Elucidating underlying cardiovascular mechanisms of these drugs provides a framework for developing novel cardioprotective anti-inflammatory medications, such as selective A2A receptor agonists.

scholarly journals Deleting myeloid IL-10 receptor signalling attenuates atherosclerosis in LDLR-/- mice by altering intestinal cholesterol fluxes

2016 ◽  
Vol 116 (09) ◽  
pp. 565-577 ◽  
Author(s):  
Gemma Brufau ◽  
Marion J. J. Gijbels ◽  
Ine M. J. Wolfs ◽  
Saskia van der Velden ◽  
Chantal C. H. Pöttgens ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Cholesterol Metabolism ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Liver Cholesterol ◽  
Specific Cell ◽  
Low Density ◽  
Atherosclerosis Development ◽  
Deficient Mice

SummaryInflammatory responses and cholesterol homeostasis are interconnected in atherogenesis. Interleukin (IL)-10 is an important anti-inflammatory cytokine, known to suppress atherosclerosis development. However, the specific cell types responsible for the atheroprotective effects of IL-10 remain to be defined and knowledge on the actions of IL-10 in cholesterol homeostasis is scarce. Here we investigated the functional involvement of myeloid IL-10-mediated atheroprotection. To do so, bone marrow from IL-10 receptor 1 (IL-10R1) wild-type and myeloid IL-10R1-deficient mice was transplanted to lethally irradiated female LDLR-/- mice. Hereafter, mice were given a high cholesterol diet for 10 weeks after which atherosclerosis development and cholesterol metabolism were investigated. In vitro, myeloid IL-10R1 deficiency resulted in a pro-inflammatory macrophage phenotype. However, in vivo significantly reduced lesion size and severity was observed. This phenotype was associated with lower myeloid cell accumulation and more apoptosis in the lesions. Additionally, a profound reduction in plasma and liver cholesterol was observed upon myeloid IL-10R1 deficiency, which was reflected in plaque lipid content. This decreased hypercholesterolaemia was associated with lowered very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) levels, likely as a response to decreased intestinal cholesterol absorption. In addition, IL-10R1 deficient mice demonstrated substantially higher faecal sterol loss caused by increased non-biliary cholesterol efflux. The induction of this process was linked to impaired ACAT2-mediated esterification of liver and plasma cholesterol. Overall, myeloid cells do not contribute to IL-10-mediated atheroprotection. In addition, this study demonstrates a novel connection between IL-10-mediated inflammation and cholesterol homeostasis in atherosclerosis. These findings make us reconsider IL-10 as a beneficial influence on atherosclerosis.Supplementary Material to this article is available online at www.thrombosis-online.com.

Restricted fetal growth and the response to dietary cholesterol in the guinea pig

1999 ◽  
Vol 277 (6) ◽  
pp. R1675-R1682 ◽  
Author(s):  
Karen L. Kind ◽  
Peter M. Clifton ◽  
Arkadi I. Katsman ◽  
Maria Tsiounis ◽  
Jeffrey S. Robinson ◽  
...  
Keyword(s):  
Birth Weight ◽  
Guinea Pig ◽  
Cholesterol Metabolism ◽  
Cholesterol Homeostasis ◽  
Cholesterol Feeding ◽  
Plasma Total Cholesterol ◽  
Maternal Undernutrition ◽  
Prenatal Growth ◽  
Ad Libitum ◽  
Size At Birth

Epidemiological studies suggest that retarded growth before birth is associated with increased plasma total and low-density lipoprotein (LDL) cholesterol concentrations in adult life. Thus perturbations of prenatal growth may permanently alter cholesterol metabolism. To determine directly whether restriction of prenatal nutrition and growth alters postnatal cholesterol homeostasis, the plasma cholesterol response to cholesterol feeding (0.25% cholesterol) was examined in adult guinea pig offspring of ad libitum-fed or moderately undernourished mothers. Maternal undernutrition (85% ad libitum intake throughout pregnancy) reduced birth weight (−13%). Plasma total cholesterol was higher prior to and following 6 wk cholesterol feeding in male offspring of undernourished mothers compared with male offspring of ad libitum-fed mothers ( P< 0.05). The influence of birth weight on cholesterol metabolism was examined by dividing the offspring into those whose birth weight was above (high) or below (low) the median birth weight. Plasma total cholesterol concentrations prior to cholesterol feeding did not differ with size at birth, but plasma total and LDL cholesterol were 31 and 34% higher, respectively, following cholesterol feeding in low- compared with high-birth weight males ( P < 0.02). The response to cholesterol feeding in female offspring was not altered by variable maternal nutrition or size at birth. Covariate analysis showed that the effect of maternal undernutrition on adult cholesterol metabolism could be partly accounted for by alterations in prenatal growth. In conclusion, maternal undernutrition and small size at birth permanently alter postnatal cholesterol homeostasis in the male guinea pig.

scholarly journals (Inverse) Agonists of Retinoic Acid–Related Orphan Receptor γ: Regulation of Immune Responses, Inflammation, and Autoimmune Disease

2020 ◽  
Vol 60 (1) ◽  
pp. 371-390 ◽  
Author(s):  
Anton M. Jetten ◽  
Donald N. Cook
Keyword(s):  
Retinoic Acid ◽  
Autoimmune Disease ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Transcriptional Activity ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Critical Role ◽  
Orphan Receptor ◽  
Inverse Agonists

Retinoic acid–related orphan receptor γt (RORγt) functions as a ligand-dependent transcription factor that regulates multiple proinflammatory genes and plays a critical role in several inflammatory and autoimmune diseases. Various endogenous and synthetic RORγ (inverse) agonists have been identified that regulate RORγ transcriptional activity, including many cholesterol intermediates and oxysterols. Changes in cholesterol biosynthesis and metabolism can therefore have a significant impact on the generation of oxysterol RORγ ligands and, consequently, can control RORγt activity and inflammation. These observations contribute to a growing literature that connects cholesterol metabolism to the regulation of immune responses and autoimmune disease. Loss of RORγ function in knockout mice and in mice treated with RORγ inverse agonists results in reduced production of proinflammatory cytokines, such as IL-17A/F, and increased resistance to autoimmune disease in several experimental rodent models. Thus, RORγt inverse agonists might provide an attractive therapeutic approach to treat a variety of autoimmune diseases.

scholarly journals Pinto Beans (Phaseolus vulgaris L.) Lower Non-HDL Cholesterol in Hamsters Fed a Diet Rich in Saturated Fat and Act on Genes Involved in Cholesterol Homeostasis

2019 ◽  
Vol 149 (6) ◽  
pp. 996-1003 ◽  
Author(s):  
An Tien Nguyen ◽  
Sami Althwab ◽  
Haowen Qiu ◽  
Richard Zbasnik ◽  
Carlos Urrea ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Molecular Mechanisms ◽  
Cholesterol Metabolism ◽  
Saturated Fatty Acids ◽  
Saturated Fat ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Liver Cholesterol ◽  
Intestinal Cholesterol Absorption ◽  
Pinto Beans

ABSTRACT Background Pinto beans contain multiple active agents such as polyphenols, flavonoids, and saponins, and have been shown to lower cholesterol, but the mechanisms involved in this effect have not been explored. Objective This study was to investigate the changes in cholesterol metabolism in response to whole pinto beans (wPB) and their hulls (hPB) supplemented into a diet rich in saturated fat and the molecular mechanisms potentially responsible for these effects in hamsters. Methods Forty-four 9-wk-old male Golden Syrian hamsters were randomly assigned to 4 diet groups (n = 11), including a 5% (wt:wt) fat diet [normal-fat diet (NF)], a 15% (wt:wt) fat diet [diet rich in saturated fat (HSF), saturated fatty acids accounted for 70% of total fatty acids], or HSF supplemented with 5% (wt:wt) wPB or 0.5% (wt:wt) hPB for 4 wk. Plasma, liver, intestinal, and fecal samples were collected to evaluate multiple cholesterol markers and gene targets. Results The plasma non-high-density lipoprotein (non-HDL) concentration was significantly reduced in the wPB- and hPB-supplemented groups by 31.9 ± 3.5% and 53.6 ± 3.2%, respectively, compared with the HSF group (P < 0.01), to concentrations comparable with the NF group. The wPB-supplemented hamsters had significantly lower liver cholesterol (45.1%, P < 0.001) and higher fecal cholesterol concentrations (94.8%, P = 0.001) than those fed the HSF. The expressions of hepatic 3-hydroxy-3-methylglutaryl CoA reductase (Hmgcr) and small intestinal acyl-coenzyme A: cholesterol acyltransferase 2 (Acat2) were significantly decreased in animals administered wPB (by 89.1% and 63.8%, respectively) and hPB (by 72.9% and 47.7%, respectively) compared with their HSF-fed counterparts (P < 0.05). The wPB normalized the expression of Acat2 to the level of the NF group. Conclusion Pinto beans remediated high cholesterol induced by HSF in male hamsters by decreasing hepatic cholesterol synthesis and intestinal cholesterol absorption, effects which were partially exerted by the hulls.

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