EMERGE Genome Wide Association Study of Cataract and Low HDL cholesterol
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PROVIDER: PRJNA75469 | ENA |
REPOSITORIES: ENA
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Project description:eMERGE Genome Wide Association Study of Cataract and Low HDL cholesterol
| PRJNA75471 | ENA
Project description:Despite considerable progress understanding genes that affect the HDL particle, its function, and cholesterol content, genes identified to date explain only a small percentage of the genetic variation. We used N-ethyl-N-nitrosourea mutagenesis in mice to discover novel genes that affect HDL cholesterol levels. Two mutant lines (Hlb218 and Hlb320) with low HDL cholesterol levels were established. Causal mutations in these lines were mapped using linkage analysis: For line Hlb218 within a 12 Mbp region on Chr 10; and for line Hlb320 within a 17 Mbp region on Chr 7. High-throughput sequencing of Hlb218 liver RNA identified a mutation in Pla2g12b. The transition of G to A leads to a cysteine to tyrosine change and most likely causes a loss of a disulfide bridge. Microarray analysis of Hlb320 liver RNA showed a 7-fold downregulation of Hpn; sequencing identified a mutation in the 3M-bM-^@M-2 splice site of exon 8. Northern blot confirmed lower mRNA expression level in Hlb320 and did not show a difference in splicing, suggesting that the mutation only affects the splicing rate. In addition to affecting HDL cholesterol, the mutated genes also lead to reduction in serum non-HDL cholesterol and triglyceride levels. Despite low HDL cholesterol levels, the mice from both mutant lines show similar atherosclerotic lesion sizes compared to control mice. These new mutant mouse models are valuable tools to further study the role of these genes, their affect on HDL cholesterol levels, and metabolism. Mutant mice were generated as part of The Jackson LaboratoryM-bM-^@M-^Ys Heart, Lung, Blood, and Sleep Disorder Mutagenesis Program by treating male C57BL/6J (B6) mice with N-ethyl-N-nitrosourea (ENU). Third generation (G3) mice were phenotyped to ensure capture of both dominant and recessive mutations. Two unique G3 animals with low HDL cholesterol levels were then used to establish new inbred lines (Hlb218 and Hlb320) by mating them with B6 mice and intercrossing the offspring with low HDL cholesterol for 7 generations. Livers from 3 Hlb218, 3 Hlb320 males, and 6 B6 male controls were obtained for gene expression analysis. The samples were randomized over Illumina Mouse-6 Expression 1.1 BeadChips .
2012-06-30 | E-GEOD-37902 | biostudies-arrayexpress
Project description:Despite considerable progress understanding genes that affect the HDL particle, its function, and cholesterol content, genes identified to date explain only a small percentage of the genetic variation. We used N-ethyl-N-nitrosourea mutagenesis in mice to discover novel genes that affect HDL cholesterol levels. Two mutant lines (Hlb218 and Hlb320) with low HDL cholesterol levels were established. Causal mutations in these lines were mapped using linkage analysis: For line Hlb218 within a 12 Mbp region on Chr 10; and for line Hlb320 within a 17 Mbp region on Chr 7. High-throughput sequencing of Hlb218 liver RNA identified a mutation in Pla2g12b. The transition of G to A leads to a cysteine to tyrosine change and most likely causes a loss of a disulfide bridge. Microarray analysis of Hlb320 liver RNA showed a 7-fold downregulation of Hpn; sequencing identified a mutation in the 3′ splice site of exon 8. Northern blot confirmed lower mRNA expression level in Hlb320 and did not show a difference in splicing, suggesting that the mutation only affects the splicing rate. In addition to affecting HDL cholesterol, the mutated genes also lead to reduction in serum non-HDL cholesterol and triglyceride levels. Despite low HDL cholesterol levels, the mice from both mutant lines show similar atherosclerotic lesion sizes compared to control mice. These new mutant mouse models are valuable tools to further study the role of these genes, their affect on HDL cholesterol levels, and metabolism.
2012-07-01 | GSE37902 | GEO
Project description:Cholesterol is an essential cell membrane component and precursor in metabolic pathways. Control of cholesterol levels is essential to human health. The endocrine hormone FGF19 potently inhibits CYP7A1, which controls a key step in cholesterol catabolism. However, the molecular mechanisms that integrate FGF19 with other cholesterol metabolic pathways are incompletely understood. Here we show that FGF19 and analogue promote HDL biogenesis and cholesterol efflux from the liver by selectively modulating liver X receptor signaling without inducing hepatic steatosis. We further identify ATP-binding cassette transporter A1 and FGFR4 as mediators of this effect. In dyslipidemic Apoe-/- mice fed a Western diet, treatment with FGF19 analogue dramatically reduced atherosclerotic lesion area in aortas. In healthy human volunteers, FGF19 analogue caused a placebo-adjusted increase in HDL cholesterol levels of 26% in seven days. These findings outline a regulatory role for FGF19 in cholesterol metabolism and advance our understanding of the mechanisms that coordinate sterol homeostasis. We used microarrays to detail the global programme of gene expression affected by FGF19 treatment in mice.
2019-01-25 | GSE117855 | GEO
Project description:Background: High-density lipoprotein (HDL)-cholesterol is inversely correlated with cardiovascular risk, but increasing its circulating concentration is insufficient to prevent adverse cardiovascular outcomes. Instead, the emerging paradigm is on increasing the function of HDL and its major protein constituent, apolipoprotein A-I (apoA-I) to increase reverse cholesterol transport. Objective: To investigate the effect of apoA-I [human] (CSL112) infusion on HDL protein composition, and provide further insights into the mechanism of action of CSL112 administered post-acute myocardial infarction (AMI). Methods: A mass spectrometry (MS)-based proteomic approach was used to evaluate changes in HDL protein composition in patients (n=50) from the AEGIS-I (ApoA-I Event Reducing in Ischemic Syndromes I) study who received either placebo or CSL112 post-AMI. HDL was immuno-isolated from patient plasma using anti-apoA-I antibodies. Cholesterol esterification rate (CER) was measured to determine lecithin-cholesterol acyl transferase (LCAT) activity. Cholesterol efflux capacity (CEC) and hepatocyte uptake were assessed using patient serum in ex vivo cell-based assays. Results: CSL112 induced extensive rearrangement of HDL proteins at 4 hours post-infusion. Levels of apolipoproteins A2, B, C, and E, as well as the acute phase proteins serum amyloid A1 and A4 were significantly reduced. By contrast, apoA-I, apoM, and LCAT significantly increased. Elevated apoA-I and LCAT levels on HDL were associated with an increase in CEC, plasma HDL-C levels, and CER in CSL112-treated patients. Furthermore, enhanced CEC was strongly associated with cholesterol uptake by hepatic cells (r=0.95 p<0.001). Conclusions: CSL112 altered HDL composition and increased HDL functionality by promoting multiple steps of the reverse cholesterol transport pathway. Clinical trial registration: URL: https://clinicaltrials.gov. Unique identifier: NCT02108262
2025-06-16 | PXD057196 | Pride
Project description:Specific mutations in Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) are responsible for a late-onset systemic amyloidosis. Carriers do not exhibit increased cardiovascular disease risk despite reduced levels of ApoA-I/ HDL-cholesterol. To explain this paradox, we show that the HDL particle profile of L75P and L174S patients presents a higher relative abundance of the 8.4 nm vs 9.6 nm particles, and that serum from patients, as well as reconstituted 8.4 and 9.6 nm HDL particles (rHDL), possess increased capacity to catalyze cholesterol efflux from macrophages. Synchrotron radiation circular dichroism and hydrogen-deuterium exchange revealed that the variants in 8.4 nm rHDL have altered secondary structure composition and display a more flexible binding to lipids compared to their native counterpart. The reduced HDL-cholesterol levels of patients carrying ApoA-I amyloidogenic variants are thus balanced by higher proportion of small, dense HDL particles and better cholesterol efflux due to altered, region-specific protein structure dynamics.
2020-11-20 | PXD021266 | Pride
Project description:eMERGE Genome Wide Association Studies of obesity
| PRJNA75997 | ENA
Project description:eMERGE Genome Wide Association Study of Dementia
| PRJNA75533 | ENA
Project description:Postprandial dyslipidemia is a recognized risk factor for atherosclerosis. High-density lipoprotein (HDL)-mediated reverse cholesterol transport plays a crucial role in mitigating this risk by clearing postprandial lipids. This study aimed to investigate the impact of esculetin, a 4-Hydroxycoumarin, on postprandial cholesterol metabolism and excretion after a high-fat meal. Esculetin significantly elevated postprandial HDL cholesterol levels in serum and postprandial bile acid levels in bile, and altered serum metabolomics in mice fed a high-fat meal, indicating esculetin promotes HDL-driven cholesterol excretion after a high-fat meal. Furthermore, esculetin administration in mice led to an increase in the ratio and phagocytic activity of a subset of adipose tissue macrophages (ATMs) expressing high levels of CD36 and Tim4. Inhibition of CD36 by Sulfo-N-succinimidyl oleate (SSO) blocked esculetin-induced elevation of postprandial serum HDL and bile acid levels in bile. Additionally, esculetin demonstrated the ability to increase the uptake of oxidized LDL (ox-LDL) via CD36 in a macrophage cell line, which might involve alteration of the epigenetic landscape controlled by CCAAT enhancer-binding protein beta (C/EBPβ). Esculetin-induced increased uptake of ox-LDL and elevation of CD36 was inhibited in C/EBPβ-deficient cells. A relatively higher expression of C/EBPβ was observed in CD36+ ATMs, and esculetin increased the ratio of C/EBPβ+ CD36+ ATMs in mice fed a lipid-rich meal. Moreover, the direct interaction between esculetin and C/EBPβ were observed by Terahertz chemical microscope. Overall, these findings suggest esculetin promotes HDL-mediated postprandial cholesterol excretion by directly binding to C/EBPβ and enhancing CD36-dependent phagocytosis in ATMs.
2024-06-12 | GSE234771 | GEO
Project description:eMERGE Genome Wide Association Studies of obesity (metabochip)
| PRJNA75993 | ENA