Similar Datasets
Project description:Physico-chemical principles of HDL-small RNA binding interactions
| PRJNA791204 | ENA
Project description:Elevated plasma levels of High Density Lipoprotein (HDL) are associated with decreased risk of cardiovascular disease (CVD). The protective role of HDL in atherosclerosis has been attributed primarily to its ability to remove excess cholesterol from lipid-laden macrophages (foam cells) within the arterial walls. However, clinical trials that raise HDL cholesterol levels have failed to show a benefit casting doubts on our basic understanding of HDL function. Atherosclerosis is a chronic inflammatory condition underlying CVD and driven in part by the recognition of metabolic danger signals by innate immune receptors on macrophages. A potential feature that could contribute to HDL’s protective effects in CVD could be HDL's anti-inflammatory nature, such as its ability to reduce endothelial cell activation. However, the molecular mechanisms by which HDL reduces inflammatory macrophage responses remain poorly understood and difficult to separate from its cholesterol depleting activity. Here we show that HDL protects against Toll like receptor (TLR)-induced inflammation both in vivo and in vitro under normocholesteremic conditions by suppressing the transcription of inflammatory cytokines in a manner independent of its ability to remove cellular cholesterol. We identify Activating Transcription Factor 3 (ATF3), a transcriptional repressor of the CREB family of basic leucine zipper transcription factors, as a HDL-inducible regulator of macrophage activation. HDL’s ability to down modulate TLR responses was severely compromised in ATF3-deficient cells demonstrating that ATF3 mediates HDL's anti-inflammatory effects and may explain the broad anti-inflammatory functions of HDL.
2013-12-08 | GSE44034 | GEO
Project description:Extracellular small RNAs (sRNAs) are abundant in many biofluids, but little is known about their mechanisms of transport and stability in RNase-rich environments. We previously reported that high-density lipoproteins (HDLs) in mice were enriched with multiple classes of sRNAs derived from the endogenous transcriptome, but also from exogenous organisms. Here, we show that human HDL transports tRNA-derived sRNAs (tDRs) from host and nonhost species, the profiles of which were found to be altered in human atherosclerosis. We hypothesized that HDL binds to tDRs through apolipoprotein A-I (apoA-I) and that these interactions are conferred by RNA-specific features. We tested this using microscale thermophoresis and electrophoretic mobility shift assays and found that HDL binds to tDRs and other single-stranded sRNAs with strong affinity but did not bind to double-stranded RNA or DNA. Furthermore, we show that natural and synthetic RNA modifications influenced tDR binding to HDL. We demonstrate that reconstituted HDL bound to tDRs only in the presence of apoA-I, and purified apoA-I alone were able to bind sRNA. Conversely, phosphatidylcholine vesicles did not bind tDRs. In summary, we conclude that HDL binds to single-stranded sRNAs likely through nonionic interactions with apoA-I. These results highlight binding properties that likely enable extracellular RNA communication and provide a foundation for future studies to manipulate HDL-sRNA interactions for therapeutic approaches to prevent or treat disease.
| S-EPMC9133651 | biostudies-literature
Project description:Dyslipidemia and inflammation play key roles in the pathogenesis of both nonalcoholic fatty liver disease (NAFLD) and atherosclerosis. NAFLD, particularly its severe form nonalcoholic steatohepatitis (NASH) is associated with increased cardiovascular disease (CVD) risk. HDL (high density lipoprotein- also a CVD risk) are decreased in NAFLD but whether HDL function is abnormal in NAFLD is unknown. Furthermore, it is unknown whether dyslipidemia contributes to reduced HDL function in NAFLD and whether hepatic inflammation further impairs HDL function in patients with NASH. Therefore, the aim of this study was to investigate HDL function and to examine the effect of dyslipidemia and inflammation on HDL metabolism in patients with biopsy-proven simple steatosis (SS) and NASH. RESULTS: Compared to controls, SS and NASH subjects had significantly higher levels of plasma triglyceride, insulin, and were more insulin resistant (HOMA, P<0.05) with no differences in total cholesterol, HDL cholesterol, ApoB100 and ApoAI levels. NAFLD patients had increased production and degradation rates of both HDLc and ApoAI that resulted in their levels remaining stable. The degradation rates also were increased of other HDL proteins, including ApoAII, ApoAIV, vitamin D-binding protein, and complement 3 (all P<0.05). NAFLD patients had increased activities of LCAT and CETP, indicating altered HDL lipidation. NAFLD induced alterations in HDL metabolism were associated with reduced anti-oxidant but increased pro-inflammatory activity of HDL. However, no differences were observed in either HDL function or the kinetics of HDLc and HDL proteins between SS and NASH subjects.
2019-08-12 | PXD010199 | Pride
Project description:Elevated plasma levels of High Density Lipoprotein (HDL) are associated with decreased risk of cardiovascular disease (CVD). The protective role of HDL in atherosclerosis has been attributed primarily to its ability to remove excess cholesterol from lipid-laden macrophages (foam cells) within the arterial walls. However, clinical trials that raise HDL cholesterol levels have failed to show a benefit casting doubts on our basic understanding of HDL function. Atherosclerosis is a chronic inflammatory condition underlying CVD and driven in part by the recognition of metabolic danger signals by innate immune receptors on macrophages. A potential feature that could contribute to HDL’s protective effects in CVD could be HDL's anti-inflammatory nature, such as its ability to reduce endothelial cell activation. However, the molecular mechanisms by which HDL reduces inflammatory macrophage responses remain poorly understood and difficult to separate from its cholesterol depleting activity. Here we show that HDL protects against Toll like receptor (TLR)-induced inflammation both in vivo and in vitro under normocholesteremic conditions by suppressing the transcription of inflammatory cytokines in a manner independent of its ability to remove cellular cholesterol. We identify Activating Transcription Factor 3 (ATF3), a transcriptional repressor of the CREB family of basic leucine zipper transcription factors, as a HDL-inducible regulator of macrophage activation. HDL’s ability to down modulate TLR responses was severely compromised in ATF3-deficient cells demonstrating that ATF3 mediates HDL's anti-inflammatory effects and may explain the broad anti-inflammatory functions of HDL. Bone marrow-derived macrophages (BMDMs) were obtained by culturing bone marrow cells from 6 to 8 week old wildtype C57BL/6 mice in DMEM supplemented with 10% FCS, 10 mg ml-1 Ciprobay-500 and 40 ng ml-1 M-CSF (R & D Systems). BMDMs of wt mice were pretreated for 6 h with HDL (2 mg ml-1 ) then stimulated with CpG (100 nM) for 4 h. Further wild type or Atf3-deficient BMDMs were pretreated with 2 mg ml-1 HDL for 6 h and subsequently stimulated with CpG (100 nM) or P3C (50 ng ml-1) for 4 h. For carotid artery injury approximately 12-week old male WT and Atf3-deficient mice were anesthetized with i.p. injection of 150 mg/kg ketaminehydrochloride (Ketanest, Pharmacia) and 0.1 mg/kg xylazinehydrochloride (Rompun 2%, Bayer). A small incision from the cranial apex of the sternum to just below the mandible was made. After careful preparation of an approximately 6 mm long segment proximal of the bifurcation, the common carotid artery was electrically denuded. A 4 mm long lesion was made by applying two serial 5 second bursts of 2 Watt using 2 mm wide forceps. The skin was then sutured and the mice allowed to recover in individual cages before returning to their littermates. Three hours later the mice received a single 200 ?l i.v. injection of 20 mg/kg HDL or PBS.
2013-12-08 | E-GEOD-44034 | biostudies-arrayexpress
Project description:HDL infusion reduces atherosclerosis in animal models and is being evaluated as a treatment in humans. While some studies have shown anti-inflammatory effects of HDL in macrophages, others have reported pro-inflammatory effects and there is no consensus on underlying mechanisms. Transcriptional profiling reveals that HDL-mediated cholesterol efflux leads to both pro- and anti-inflammatory effects in LPS-stimulated macrophages. While early anti-inflammatory effects reflect reduced TLR4 levels, late anti-inflammatory effects are due to reduced interferon receptor signaling. Pro-inflammatory effects occur late and are ER stress responses mediated by IRE1a/ASK1/p38 MAPK signaling under conditions of marked cholesterol depletion. rHDL infusions in hypercholesterolemic atherosclerotic mice produced moderate anti-inflammatory effects in lesional macrophages without pro-inflammatory gene expression changes suggesting a beneficial therapeutic effect of HDL in vivo.
2020-04-04 | GSE129347 | GEO
Project description:High density lipoproteins (HDL) promote homeostasis and counteract stressful tissue damage that underlie cardiovascular and other diseases by mediating reverse cholesterol transport, reducing inflammation, and abrogating oxidative damage. However, metabolically stressful conditions associated with atherosclerosis can impair these effects. Hepatocytes play a major role in the genesis and maturation of circulating HDL. Liver stress elicits marked regulatory changes to circulating HDL abundance and composition, which affect its functionality. Mechanisms linking liver stress to HDL functionality are incompletely understood. In this study, we sought to determine whether stress defending transcription factors nuclear factor erythroid 2 related factor-1 (NRF1) and -2 (NRF2) promote hepatocyte production of functional HDL. Using genetically engineered mouse models briefly fed a mild metabolically stressful diet, we investigated the effect of hepatocyte-specific deletion of NRF1, NRF2, or both on circulating HDL cholesterol level, protein composition, and function. Combined deletion, but not single gene deletion, reduced HDL cholesterol content as well as the capacity of HDL to accept cholesterol efflux from cultured macrophages and to counteract tumor necrosis factor a-induced inflammatory effect on cultured endothelial cells. This coincided with substantial alteration to the circulating HDL proteome, which correlated with liver gene expression profiles of corresponding proteins. Altogether, our findings show complementary actions by hepatocyte NRF1 and NRF2 play a role in shaping HDL composition and promote production of functionally viable HDL. Consequently, our study illuminates the possibility that enhancing stress defense programming in the liver may improve atheroprotective and perhaps other health promoting actions of HDL.
2023-07-03 | PXD042103 | Pride
Project description:miRNAs and other small RNAs have been found associated with high-density lipoproteins (HDL). The aim of this study was to investigate the miRNA signature on human HDL from 10 donors.
2019-01-03 | GSE124559 | GEO
Project description:Engineered FGF19 promotes HDL biogenesis and transhepatic cholesterol efflux to prevent atherosclerosis
| PRJNA483446 | ENA
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