Project description:Genetic variants at the TRIB1 (Tribbles-homolog 1) gene locus are strongly associated with plasma lipid traits and the risk of coronary artery disease in humans. In this study, we analyzed the consequences of Trib1-deficiency (Trib1-/-) on hepatic gene expression in mice on the atherosclerosis-susceptible LDL-receptor deficient (Ldlr-/-) background. Therefore, Trib1-/- mice were crossed onto the Ldlr-/- background to generate double knockout mice (Trib1-/-Ldlr-/-) and fed a semisynthetic, modified AIN76 diet (0.02% cholesterol, 4.3% fat). At 20 weeks of age, Trib1-/-Ldlr-/- mice and Trib1+/+Ldlr-/- control mice were sacrificed and liver tissue was snap frozen in liquid nitrogen and stored at -80°C until further processing. Total RNA was isolated from liver tissue (n=8 mice per genotype) and subjected to microarray gene expression analysis.
Project description:Background---For decades, plasma lipid levels have been known risk factors of atherosclerosis. Recently, inflammation has gained acceptance as a crucial event in the pathogenesis and development of atherosclerosis. A number of studies have provided some insights into the relationships between the two aspects of atherosclerosis: plasma lipids --- the risk factors, and circulating leukocytes --- the effectors of inflammation. In this study, we investigate the relationships between plasma lipids and leukocytes. Methods and Results---No significant correlation was found between leukocyte counts and plasma lipid levels in 74 individuals. Profiling and analyzing the leukocyte gene expression of 32 individuals revealed distinctive patterns in response to plasma lipid levels: 1) genes involved in lipid metabolism and in the electron transport chain were positively correlated with triglycerides and low-density lipoprotein cholesterol levels, and negatively correlated with high-density lipoprotein cholesterol levels; 2) genes involved in platelet activation were negatively correlated with high-density lipoprotein cholesterol levels; 3) transcription factors regulating lipidgenesis-related genes were correlated with plasma lipid levels; 4) a number of genes correlated to plasma lipid levels were found located in the regions of known QTLs associated with hyperlipemia. Conclusions--- We discovered interesting patterns of leukocyte gene expression in response to plasma lipid levels. Most importantly, genes involved in lipid metabolism, the electron transportation chain, and platelet activation were found correlated with plasma lipid levels. We suggest that leukocytes respond to changing plasma lipid levels by regulating a network of genes, including genes involved in lipid and fatty acid metabolism, through the activation of key transcription factors, such as sterol regulatory element binding transcription factors and peroxisome proliferative activated receptors. Experiment Overall Design: 1. Profile gene expression in human peripheral blood cells. Experiment Overall Design: 2. Test blood biochemistry and blood cell differential counts Experiment Overall Design: 3. Examine the correlation between blood gene expression and blood lipid levels. Experiment Overall Design: 4. Explore possible pathways with significant genes. Experiment Overall Design: 5. Validate a number of significant genes with RT-PCR
Project description:Background---For decades, plasma lipid levels have been known risk factors of atherosclerosis. Recently, inflammation has gained acceptance as a crucial event in the pathogenesis and development of atherosclerosis. A number of studies have provided some insights into the relationships between the two aspects of atherosclerosis: plasma lipids --- the risk factors, and circulating leukocytes --- the effectors of inflammation. In this study, we investigate the relationships between plasma lipids and leukocytes. Methods and Results---No significant correlation was found between leukocyte counts and plasma lipid levels in 74 individuals. Profiling and analyzing the leukocyte gene expression of 32 individuals revealed distinctive patterns in response to plasma lipid levels: 1) genes involved in lipid metabolism and in the electron transport chain were positively correlated with triglycerides and low-density lipoprotein cholesterol levels, and negatively correlated with high-density lipoprotein cholesterol levels; 2) genes involved in platelet activation were negatively correlated with high-density lipoprotein cholesterol levels; 3) transcription factors regulating lipidgenesis-related genes were correlated with plasma lipid levels; 4) a number of genes correlated to plasma lipid levels were found located in the regions of known QTLs associated with hyperlipemia. Conclusions--- We discovered interesting patterns of leukocyte gene expression in response to plasma lipid levels. Most importantly, genes involved in lipid metabolism, the electron transportation chain, and platelet activation were found correlated with plasma lipid levels. We suggest that leukocytes respond to changing plasma lipid levels by regulating a network of genes, including genes involved in lipid and fatty acid metabolism, through the activation of key transcription factors, such as sterol regulatory element binding transcription factors and peroxisome proliferative activated receptors. Keywords: Atherosclerosis, leukocyte, lipid, gene expression
Project description:Atherosclerosis is characterized by the pathological accumulation of cholesterol-laden macrophages in the arterial wall. Atherosclerosis is also the main underlying cause of cardiovascular diseases (CVDs), and its development is largely driven by elevated plasma cholesterol. Strong epidemiological data find an inverse association between plasma β-carotene with atherosclerosis, and we recently showed that β-carotene oxygenase 1 (BCO1) activity, responsible for β-carotene cleavage to vitamin A, is associated with reduced plasma cholesterol in humans and mice. In this study, we explore whether intact β-carotene or vitamin A affect atherosclerosis progression in the atheroprone low-density lipoprotein receptor (LDLR) - deficient mice. In comparison to control-fed Ldlr-/- mice, β-carotene-supplemented mice showed reduced atherosclerotic lesion size at the level of the aortic root and plasma cholesterol levels (P = 0.0003). These changes were absent in Ldlr-/-/Bco1-/- mice, despite accumulating β-carotene in plasma and atherosclerotic lesions. We discarded the implication of myeloid BCO1 in the development of atherosclerosis by performing bone marrow transplant experiments. Lipid production assays found that retinoic acid, the active form of vitamin A, reduced the secretion of newly synthetized triglyceride and cholesteryl ester in cell culture and mice. Overall, our findings provide insights into the role of BCO1 activity and vitamin A in atherosclerosis progression through the regulation of hepatic lipid metabolism.
Project description:Dietary fiber such as inulin have been reported to promote cardiovascular and metabolic health. However, the mechanisms involved are not well understood. We studied effects of inulin on lipid metabolism in Ldlr deficient atherosclerosis mouse model using lipidomics and transcriptomics. Plasma and tissues were collected at 10 days and/or 12 weeks after feeding an atherogenic diet supplemented with inulin or cellulose (control).
Project description:In this study, mice with different genotypes and fed diets with different lipid content were enrolled, aiming to set up an atlas of miRNA expression levels in different organs with a relevant role in lipid/lipoprotein metabolism. Specifically, three genotypes were investigated: C57Bl/6 mice as controls, together with mice knock-out (KO) for LDLr (low-density lipoprotein receptor) and for PCSK9 (proprotein convertase subtilisin/kexin type 9). LDLr and PCSK9 are both involved in LDL turnover, the former mediating LDL clearance [PMID: 19299327], the latter causing the degradation of the LDLr protein [PMID: 17080197]. As a result, LDLrKO mice, because of their impaired LDL catabolism, are hypercholesterolemic and prone to atherosclerosis development, particularly when fed high-fat, cholesterol-containing diets [PMID: 8349823; PMID: 8182121]. On the contrary, PCSK9KO mice, characterized by an accelerated LDL catabolism, are hypocholesterolemic and atherosclerosis resistant [PMID: 15805190]. miRNA expression was investigated in liver, intestine, aorta, white adipose tissue and brain of mice on both standard and Western diet.
Project description:Finasteride is commonly prescribed to treat benign prostate hyperplasia and male-pattern baldness in cis men and, more recently, trans individuals. However, the effect of finasteride on cardiovascular disease remains elusive. We evaluated the role of finasteride on atherosclerosis using low-density lipoprotein (LDL) receptor-deficient (Ldlr-/-) mice. Next, we examined the relevance to humans by analysing the data deposited between 2009 and 2016 in the National Health and Nutrition Examination Survey (NHANES). We show that finasteride reduces total plasma cholesterol and delays the development of atherosclerosis in Ldlr-/- mice. Finasteride reduced monocytosis, monocyte recruitment to the lesion, macrophage lesion content, and necrotic core area, the latter of which is an indicator of plaque vulnerability in humans. RNA sequencing analysis revealed a downregulation of inflammatory pathways and an upregulation of bile acid metabolism, oxidative phosphorylation, and cholesterol pathways in the liver of mice taking finasteride. Men reporting the use of finasteride showed lower plasma levels of cholesterol and LDL-cholesterol than those not taking the drug. Our data unveil finasteride as a potential treatment to delay cardiovascular disease in people by improving the plasma lipid profile.