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International Journal of Molecular... Mar 2022Lipoprotein(a) (Lp(a)) is one of the strongest causal risk factors of atherosclerotic disease. It is rich in cholesteryl ester and composed of apolipoprotein B and... (Review)
Review
Lipoprotein(a) (Lp(a)) is one of the strongest causal risk factors of atherosclerotic disease. It is rich in cholesteryl ester and composed of apolipoprotein B and apo(a). Plasma Lp(a) levels are determined by apo(a) transcriptional activity driven by a direct repeat (DR) response element in the apo(a) promoter under the control of (HNF)4α Farnesoid-X receptor (FXR) ligands play a key role in the downregulation of expression. In vitro studies on the catabolism of Lp(a) have revealed that Lp(a) binds to several specific lipoprotein receptors; however, their in vivo role remains elusive. There are more than 1000 publications on the role of diabetes mellitus (DM) in Lp(a) metabolism; however, the data is often inconsistent and confusing. In patients suffering from Type-I diabetes mellitus (T1DM), provided they are metabolically well-controlled, Lp(a) plasma concentrations are directly comparable to healthy individuals. In contrast, there exists a paradox in T2DM patients, as many of these patients have reduced Lp(a) levels; however, they are still at an increased cardiovascular risk. The Lp(a) lowering mechanism observed in T2DM patients is most probably caused by mutations in the mature-onset diabetes of the young (MODY) gene and possibly other polymorphisms in key transcription factors of the apolipoprotein (a) gene (APOA).
Topics: Apolipoproteins A; Apoprotein(a); Cardiovascular Diseases; Diabetes Mellitus, Type 2; Humans; Lipoprotein(a)
PubMed: 35408941
DOI: 10.3390/ijms23073584 -
Atherosclerosis May 2022Epidemiological studies investigating the association between a biomarker and a disease have many limitations. The most prominent among these is that we cannot impute... (Review)
Review
Epidemiological studies investigating the association between a biomarker and a disease have many limitations. The most prominent among these is that we cannot impute causality purely from a statistical association. If we observe an association, the biomarker might really be causal for the development of the disease, the association might be caused by a confounding variable or by reverse causation. With Mendelian Randomization (MR) methods, we have a potent tool at hand to derive evidence for a direct causal relationship. One of the core assumptions of MR studies is that genetic variants can be identified, which are strongly associated with the biomarker of interest, and can serve as an instrument indicating lifetime exposure. Since Lp(a) is primarily genetically determined by KIV-2 repeats, that in turn determine apo(a) isoform size, and by numerous single nucleotide polymorphisms (SNPs) and SNP-scores, this assumption is definitely fulfilled and it is probably one of the best phenotypes to be studied with Mendelian Randomization methods. The first studies evaluating the causal role of Lp(a) for cardiovascular diseases were performed in the early 1990s and more recently gained interest after several Lp(a)-increasing SNPs were identified in genome wide association studies. In this review, the principles behind MR methods are explained, together with their important role for Lp(a) research, particularly reconsidered in their historic context. MR methods have also been used to estimate the extent of Lp(a) reduction that would be required to yield a clinically meaningful reduction in outcomes in clinical intervention trials.
Topics: Apolipoproteins A; Apoprotein(a); Biomarkers; Genome-Wide Association Study; Lipoprotein(a); Mendelian Randomization Analysis; Polymorphism, Single Nucleotide
PubMed: 35606074
DOI: 10.1016/j.atherosclerosis.2022.04.013 -
Molecules (Basel, Switzerland) Mar 2021Membrane-scaffolding proteins (MSPs) derived from apolipoprotein A-1 have become a versatile tool in generating nano-sized discoidal membrane mimetics (nanodiscs) for...
Membrane-scaffolding proteins (MSPs) derived from apolipoprotein A-1 have become a versatile tool in generating nano-sized discoidal membrane mimetics (nanodiscs) for membrane protein research. Recent efforts have aimed at exploiting their controlled lipid protein ratio and size distribution to arrange membrane proteins in regular supramolecular structures for diffraction studies. Thereby, direct membrane protein crystallization, which has remained the limiting factor in structure determination of membrane proteins, would be circumvented. We describe here the formation of multimers of membrane-scaffolding protein MSP1D1-bounded nanodiscs using the thiol reactivity of engineered cysteines. The mutated positions N42 and K163 in MSP1D1 were chosen to support chemical modification as evidenced by fluorescent labeling with pyrene. Minimal interference with the nanodisc formation and structure was demonstrated by circular dichroism spectroscopy, differential light scattering and size exclusion chromatography. The direct disulphide bond formation of nanodiscs formed by the MSP1D1_N42C variant led to dimers and trimers with low yield. In contrast, transmission electron microscopy revealed that the attachment of oligonucleotides to the engineered cysteines of MSP1D1 allowed the growth of submicron-sized tracts of stacked nanodiscs through the hybridization of nanodisc populations carrying complementary strands and a flexible spacer.
Topics: Amino Acid Sequence; Apolipoprotein A-I; DNA; Lipid Bilayers; Membrane Proteins; Microscopy, Electron, Transmission; Nanostructures; Phospholipids
PubMed: 33809519
DOI: 10.3390/molecules26061647 -
Biochimica Et Biophysica Acta.... Jul 2022Adenosine triphosphate-binding cassette transporter subfamily A member 7 (ABCA7) performs incompletely understood biochemical functions that affect pathogenesis of...
Adenosine triphosphate-binding cassette transporter subfamily A member 7 (ABCA7) performs incompletely understood biochemical functions that affect pathogenesis of Alzheimer's disease. ABCA7 is most similar in primary structure to ABCA1, the protein that mediates cell lipid efflux and formation of high-density lipoprotein (HDL). Lipid metabolic labeling/tracer efflux assays were employed to investigate lipid efflux in BHK-ABCA7(low expression), BHK-ABCA7(high expression) and BHK-ABCA1 cells. Shotgun lipid mass spectrometry was used to determine lipid composition of HDL synthesized by BHK-ABCA7 and BHK-ABCA1 cells. BHK-ABCA7(low) cells exhibited significant efflux only of choline-phospholipid and phosphatidylinositol. BHK-ABCA7(high) cells had significant cholesterol and choline-phospholipid efflux to apolipoprotein (apo) A-I, apo E, the 18A peptide, HDL, plasma and cerebrospinal fluid and significant efflux of sphingosine-lipid, serine-lipid (which is composed of phosphatidylserine and phosphatidylethanolamine in BHK cells) and phosphatidylinositol to apo A-I. In efflux assays to apo A-I, after adjustment to choline-phospholipid, ABCA7-mediated efflux removed ~4 times more serine-lipid and phosphatidylinositol than ABCA1-mediated efflux, while ABCA1-mediated efflux removed ~3 times more cholesterol than ABCA7-mediated efflux. Shotgun lipidomic analysis revealed that ABCA7-HDL had ~20 mol% less phosphatidylcholine and 3-5 times more serine-lipid and phosphatidylinositol than ABCA1-HDL, while ABCA1-HDL contained only ~6 mol% (or ~1.1 times) more cholesterol than ABCA7-HDL. The discrepancy between the tracer efflux assays and shotgun lipidomics with respect to cholesterol may be explained by an underestimate of ABCA7-mediated cholesterol efflux in the former approach. Overall, these results suggest that ABCA7 lacks specificity for phosphatidylcholine and releases significantly but not dramatically less cholesterol in comparison with ABCA1.
Topics: ATP-Binding Cassette Transporters; Apolipoprotein A-I; Cholesterol; Choline; Lipoproteins, HDL; Phosphatidylcholines; Phosphatidylinositols; Phospholipids; Serine
PubMed: 35381375
DOI: 10.1016/j.bbalip.2022.159157 -
Best Practice & Research. Clinical... Jul 2023COVID-19 infections decrease total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I, A-II, and B levels while triglyceride levels may be increased or inappropriately... (Review)
Review
COVID-19 infections decrease total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I, A-II, and B levels while triglyceride levels may be increased or inappropriately normal for the poor nutritional status. The degree of reduction in total cholesterol, LDL-C, HDL-C, and apolipoprotein A-I are predictive of mortality. With recovery lipid/lipoprotein levels return towards pre-infection levels and studies have even suggested an increased risk of dyslipidemia post-COVID-19 infection. The potential mechanisms for these changes in lipid and lipoprotein levels are discussed. Decreased HDL-C and apolipoprotein A-I levels measured many years prior to COVID-19 infections are associated with an increased risk of severe COVID-19 infections while LDL-C, apolipoprotein B, Lp (a), and triglyceride levels were not consistently associated with an increased risk. Finally, data suggest that omega-3-fatty acids and PCSK9 inhibitors may reduce the severity of COVID-19 infections. Thus, COVID-19 infections alter lipid/lipoprotein levels and HDL-C levels may affect the risk of developing COVID-19 infections.
Topics: Humans; Proprotein Convertase 9; Triglycerides; Apolipoprotein A-I; Cholesterol, LDL; COVID-19; Lipoproteins; Cholesterol, HDL
PubMed: 36894344
DOI: 10.1016/j.beem.2023.101751 -
Frontiers in Endocrinology 2023This study aims to evaluate the effect of acupuncture on the emotion domain and metabolic parameters of Chinese women with polycystic ovarian syndrome (PCOS) by... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
This study aims to evaluate the effect of acupuncture on the emotion domain and metabolic parameters of Chinese women with polycystic ovarian syndrome (PCOS) by secondary analysis of a randomized clinical trial, conducted from 6 July 2012 to 7 October 2015.
METHOD
In this study, we investigated the effects of acupuncture (458 patients) and sham acupuncture (468 patients) on metabolic parameters, serum ions, and all quality-of-life scale scores related to PCOS. The quality of life of patients was evaluated using five relevant scales, operated by the research assistant, namely, PCOSQ, SF-36, and ChiQOL, as well as Zung-SAS and Zung-SDS. Metabolic parameters and serum ions were measured.
RESULTS
A reduction in acne score, AN, Hcy, and LDL-C, and an increase in the level of lipoprotein α, Apo A1, and Apo A1/Apo B were observed in the acupuncture group after 4 months' intervention after adjusting clomiphene and reproductive outcome (< 0.05). An increase in SF-36 total scores, RP and RE scores, ChiQOL total scores, and emotion domain scores was observed in the acupuncture group after 4 months' intervention, while PF and HT scores were decreased (adjusted < 0.05). Those same changes were observed in sham acupuncture. Meanwhile, the serum levels of Ca, K, and Cl were elevated in the acupuncture group after the interventions (adjusted < 0.005). There were no significant differences in HOMA-IR, MetS, FPG, FINS, HDL-C, TG, Apo B, and level of serum P, Mg, and Na. Also, no changes in BP, GH, VT, SF, physical form domain, and spirit domain were observed after treatment.
CONCLUSION
Acupuncture can improve not only the emotional changes in SF-36 scores and ChiQOL scores, but also lipid metabolism, implying that it may have a correlation between emotional change and lipid metabolism. Furthermore, acupuncture can also regulate the changes of serum Ca, K, and Cl.
CLINICAL TRIAL REGISTRATION
ClinicalTrials.gov, identifier NCT01573858.
Topics: Humans; Female; Apolipoprotein A-I; Polycystic Ovary Syndrome; Quality of Life; Acupuncture Therapy; Apolipoproteins B; Emotions
PubMed: 37711905
DOI: 10.3389/fendo.2023.1237260 -
Arteriosclerosis, Thrombosis, and... Oct 2023High levels of Lp(a) (lipoprotein(a)) are associated with multiple forms of cardiovascular disease. Lp(a) consists of an apoB-containing particle attached to the...
BACKGROUND
High levels of Lp(a) (lipoprotein(a)) are associated with multiple forms of cardiovascular disease. Lp(a) consists of an apoB-containing particle attached to the plasminogen homologue apo(a). The pathways for Lp(a) clearance are not well understood. We previously discovered that the plasminogen receptor PlgRKT (plasminogen receptor with a C-terminal lysine) promoted Lp(a) uptake in liver cells. Here, we aimed to further define the role of PlgRKT and to investigate the role of 2 other plasminogen receptors, annexin A2 and S100A10 (S100 calcium-binding protein A10) in the endocytosis of Lp(a).
METHODS
Human hepatocellular carcinoma (HepG2) cells and haploid human fibroblast-like (HAP1) cells were used for overexpression and knockout of plasminogen receptors. The uptake of Lp(a), LDL (low-density lipoprotein), apo(a), and endocytic cargos was visualized and quantified by confocal microscopy and Western blotting.
RESULTS
The uptake of both Lp(a) and apo(a), but not LDL, was significantly increased in HepG2 and HAP1 cells overexpressing PlgRKT, annexin A2, or S100A10. Conversely, Lp(a) and apo(a), but not LDL, uptake was significantly reduced in HAP1 cells in which PlgRKT and S100A10 were knocked out. Surface binding studies in HepG2 cells showed that overexpression of PlgRKT, but not annexin A2 or S100A10, increased Lp(a) and apo(a) plasma membrane binding. Annexin A2 and S100A10, on the other hand, appeared to regulate macropinocytosis with both proteins significantly increasing the uptake of the macropinocytosis marker dextran when overexpressed in HepG2 and HAP1 cells and knockout of S100A10 significantly reducing dextran uptake. Bringing these observations together, we tested the effect of a PI3K (phosphoinositide-3-kinase) inhibitor, known to inhibit macropinocytosis, on Lp(a) uptake. Results showed a concentration-dependent reduction confirming that Lp(a) uptake was indeed mediated by macropinocytosis.
CONCLUSIONS
These findings uncover a novel pathway for Lp(a) endocytosis involving multiple plasminogen receptors that enhance surface binding and stimulate macropinocytosis of Lp(a). Although the findings were produced in cell culture models that have limitations, they could have clinical relevance since drugs that inhibit macropinocytosis are in clinical use, that is, the PI3K inhibitors for cancer therapy and some antidepressant compounds.
Topics: Humans; Plasminogen; Lipoprotein(a); Annexin A2; Dextrans; Phosphatidylinositol 3-Kinases; Carrier Proteins; Apolipoproteins A
PubMed: 37589135
DOI: 10.1161/ATVBAHA.123.319344 -
Travel Medicine and Infectious Disease 2021Apolipoproteins are predictive biomarkers for cardiovascular, neoplasms and cerebrovascular diseases and are postulated as prognostic biomarkers in infectious diseases,... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Apolipoproteins are predictive biomarkers for cardiovascular, neoplasms and cerebrovascular diseases and are postulated as prognostic biomarkers in infectious diseases, as COVID-19. Thus, we assessed the prognosis value of apolipoproteins for COVID-19 severity and mortality.
METHODS
We conducted a systematic review and meta-analysis using observational studies that reported the association between apolipoproteins and severity or mortality in COVID-19 patients. Newcastle-Ottawa was used for the quality assessment of included studies. Effects measurements were shown as odds ratios (ORs) with 95% confidence intervals (CIs), and Egger-test was developed for assessing the risk of bias publication.
RESULTS
We analyzed 12 cohort studies (n = 3580). Patients with low ApoliproteinA1 (ApoA1) (OR 0.35; 95%CI 0.24 to 0.49; P < 0.001) and ApoliproteinB (ApoB) (OR = 0.78; 95%CI 0.69 to 0.87; P < 0.001) values had a higher risk of developing severe disease. ApoB/ApoA1 ratio showed no statistically significant association with higher odds of severity. Low ApoA1 levels were associated with higher odds of all-cause mortality (OR = 0.34; 95%CI 0.20 to 0.57; P < 0.001). ApoB values showed no statistically significant association with a high risk of all-cause mortality.
CONCLUSION
We suggest that adequate levels of ApoA1 and ApoB can be a protective factor for severity in COVID-19, and ApoB/ApoA1 ratio did not show predictive utility for severity.
Topics: Apolipoprotein A-I; Apolipoproteins; COVID-19; Humans; Prognosis; Risk Factors; SARS-CoV-2
PubMed: 34752921
DOI: 10.1016/j.tmaid.2021.102200 -
The Journal of Clinical Investigation Sep 2023BACKGROUNDCellular cholesterol efflux capacity (CEC) is a better predictor of cardiovascular disease (CVD) events than HDL-cholesterol (HDL-C) but is not suitable as a...
BACKGROUNDCellular cholesterol efflux capacity (CEC) is a better predictor of cardiovascular disease (CVD) events than HDL-cholesterol (HDL-C) but is not suitable as a routine clinical assay.METHODSWe developed an HDL-specific phospholipid efflux (HDL-SPE) assay to assess HDL functionality based on whole plasma HDL apolipoprotein-mediated solubilization of fluorescent phosphatidylethanolamine from artificial lipid donor particles. We first assessed the association of HDL-SPE with prevalent coronary artery disease (CAD): study I included NIH severe-CAD (n = 50) and non-CAD (n = 50) participants, who were frequency matched for sex, BMI, type 2 diabetes mellitus, and smoking; study II included Japanese CAD (n = 70) and non-CAD (n = 154) participants. We also examined the association of HDL-SPE with incident CVD events in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study comparing 340 patients with 340 controls individually matched for age, sex, smoking, and HDL-C levels.RESULTSReceiver operating characteristic curves revealed stronger associations of HDL-SPE with prevalent CAD. The AUCs in study I were as follows: HDL-SPE, 0.68; apolipoprotein A-I (apoA-I), 0.62; HDL-C, 0.63; and CEC, 0.52. The AUCs in study II were as follows: HDL-SPE, 0.83; apoA-I, 0.64; and HDL-C, 0.53. Also longitudinally, HDL-SPE was significantly associated with incident CVD events independent of traditional risk factors with ORs below 0.2 per SD increment in the PREVEND study (P < 0.001).CONCLUSIONHDL-SPE could serve as a routine clinical assay for improving CVD risk assessment and drug discovery.TRIAL REGISTRATIONClinicalTrials.gov NCT01621594.FUNDINGNHLBI Intramural Research Program, NIH (HL006095-06).
Topics: Humans; Lipoproteins, HDL; Cardiovascular Diseases; Apolipoprotein A-I; Diabetes Mellitus, Type 2; Coronary Artery Disease; Cholesterol, HDL; Phospholipids
PubMed: 37471145
DOI: 10.1172/JCI165370 -
Journal of Healthcare Engineering 2022To analyze apolipoprotein-A for its predictive value for long-term death in individuals suffering from acute ST-segment elevation myocardial infarction following...
OBJECTIVE
To analyze apolipoprotein-A for its predictive value for long-term death in individuals suffering from acute ST-segment elevation myocardial infarction following percutaneous coronary intervention.
METHODS
We selected patients suffering from acute ST-segment elevation myocardial infarction who underwent emergency PCI at the Affiliated Hospital of Putian University from January 2017 to August 2019. The patients were divided into a high-Apo-A group and low-Apo-A group, and we observed all-cause deaths of patients in the 2 groups within 2 years.
RESULTS
The ROC curve analysis indicated the best critical value for predicting 2-year mortality as 0.8150 (area under the curve was 0.626, sensitivity 75.1%, and specificity 51.9%). There was no statistical difference among the two groups in gender, age, lesion vessel, and comorbidities. The two groups had statistically significant differences in apolipoprotein-B/A, high-density lipoprotein, apolipoprotein-A, and hypersensitivity C-reactive protein. Correlation analysis showed a significant negative correlation between apolipoprotein-A and hypersensitive C-reactive protein. The results of the 24-month analysis indicated the incidence of all-cause mortality as higher in the low-Apo-A group, and Kaplan-Meier survival analysis showed the same trend.
CONCLUSION
Apolipoprotein-A can predict the potential for long-term mortality among individuals having acute ST-segment elevation myocardial infarction.
Topics: Apolipoproteins; Apolipoproteins A; C-Reactive Protein; Humans; Percutaneous Coronary Intervention; ST Elevation Myocardial Infarction; Treatment Outcome
PubMed: 35075388
DOI: 10.1155/2022/5941117