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At least 19 recordsLinked to original sources
PubMed1976

Is decreased activity of C-II activated lipoprotein lipase in type III hyperlipoproteinemia (broad-beta-disease) a cause or an effect of increased apolipoprotein E levels?

Apolipoprotein E (ApoE; "arginine-rich" polypeptide) strongly inhibited both C-I and C-II activated lipoprotein lipases but not the protamine insensitive triglyceride lipase. Inhibition of lipoprotein lipases by ApoE in contrast to inhibition by C-III was not reversed to any significant extent by either increased concentration of activator or triglyceride in the substrate. Our previous studies have shown that in a type III hyperlipoproteinemia (broad-beta-disease) a post-heparin plasma lipoprotein lipase activated by C-II polypeptide of lipoprotein C is decreased in enzyme activity and exhibits an impaired ability to hydrolyze triglycerides in very low density lipoproteins. Type III patients are characterized by elevated concentrations of ApoE in the serum. The data presented in this report suggest that the decreased C-II activated lipoprotein lipase may be further aggravated by increased ApoE levels. Since this enzyme is involved in the catabolism and removal of lipoproteins, decreased activity of C-II activativated lipoprotein lipase may presumably be responsible for increased ApoE.

Apolipoproteins↗
PubMed1976

Determination of human apolipoprotein E by electroimmunoassay.

1. Apolipoprotein E ("arginine-rich" polypeptide) was isolated from delipidized human very low density lipoproteins by agarose column chromatography in the presence of 6 M guanidine-hydrochloride. 2. An electroimmunoassay ("rocket" electrophoresis) is described for quantitative determination of human serum apolipoprotein E. Purified apolipoprotein E was used for the preparation of monospecific antisera and standardization of assay. This sensitive, specific, rapid (time required for the completion of the assay is 5 h) and precise (the within- and between-assay coefficients of variation are 5 and 8%, respectively) assay is applicable to measurement of apolipoprotein E in whole serum and density classes. The results correlated well with those obtained by radial immunodiffusion (r = 0.85). 3. Serum apolipoprotein E levels of normal subjects and hyperlipoproteinemic phenotypes IIa, IIb and IV were the same (10 to 16 mg/100 ml). In contrast, patients with type III and V hyperlipoproteinemias had markedly elevated serum apolipoprotein E levels )27 and 25 mg/100 ml, respectively). The apolipoprotein E in serum of normolipidemic subjects was equally distributed among three major lipoprotein density classes: d less than 1.030 g/ml (27%), d 1.030-1.063 g/ml (36%)and d 1.063-1.21 g/ml (37%).

Amino Acids↗
PubMed1977

Type III hyperlipoproteinemia: diagnosis in whole plasma by apolipoprotein-E immunoassay.

Because the cholesterol-rich very low density (VLD) lipoproteins of subjects with type III hyperlipoproteinemia are distinctively enriched in apolipoprotein E, a radial immunodiffusion assay for apolipoprotein E in whole plasma was developed. Its diagnostic usefulness was tested in randomly selected (n = 174) and hyperlipidemic (n = 61) subsets of an adult employee population and a hyperlipidemia clinic referral group (n = 63), which included 18 patients with well-documented type III hyperlipoproteinemia. Apolipoprotein-E levels were normally distributed among the random population subset, were equal between the two sexes, and increased little with age. The mean and 99th percentile values were 24.6 and 40.1 mg/dl, respectively. All subjects with type III patterns as assigned by standard criteria from both population (n = 4) and referral sources exceeded this 99th percentile (chi +/- SD = 54.7 +/- 9.7 mg/dl). Hence a plasma apolipoprotein-E concentration exceeding 40 mg/dl appears diagnostic of type III hyperlipoproteinemia, representing the first application of an apolipoprotein immunoassay to improved diagnosis of the hyperlipoproteinemias.

Adult↗
PubMed1979

Polymorphism of apolipoprotein E. II. Genetics of hyperlipoproteinemia type III.

Apolipoprotein E from human serum shows a genetic polymorphism determined by two autosomal codominant alleles, Apo En and Apo Ed. Homozygosity for the gene Apo Ed (phenotype Apo E-D) results in primary dysbetalipoproteinemia, but only some individuals with this phenotype develop gross hyperlipidemia (hyperlipoproteinemia type III). Vertical transmission of dysbetalipoproteinemia represents pseudodominance due to the high frequency of the gene Apo Ed. Dysbetalipoproteinemia is already expressed in childhood. To assess the influence of other genes on the expression of hyperlipidemia in phenotype Apo E-D, comparative studies were carried out in kindreds of hypercholesterolemic (group A) and normo- or hypocholesterolemic probands with dysbetalipoproteinemia (group B). This demonstrated the occurrence of familial (non-type III) forms of hyperlipidemia in group A but not in group B kindreds. Distribution of lipoprotein phenotypes in five of the group A kindreds was consistent with the occurrence of familial combined hyperlipidemia. Apo E phenotypes and hyperlipidemia segregated independently. It is concluded that primary dysbetalipoproteinemia is a frequent monogenic variant of lipoprotein metabolism, but not a disease. Coincidence in one individual of genes for this specific dyslipoproteinemia with any of the genes for monogenic or polygenic forms of familial hyperlipidemia results in hyperlipoproteinemia type III. Hence hyperlipoproteinemia type III is caused by at least two non-allelic genes and is a polygenic disorder.

Adolescent↗
PubMed2026

Apolipoprotein E promotes papillary thyroid carcinoma progression by activating PINK1/Parkin-mediated mitophagy.

BACKGROUND: Increasing evidence supports a progression-related role of apolipoprotein E (APOE) in papillary thyroid carcinoma (PTC), yet a clear mechanistic explanation for this association is still lacking. Considering the pivotal role of mitochondrial homeostasis in tumorigenesis, the potential role of APOE in promoting PTC progression through mitophagy regulation was investigated. Additionally, the involvement of the PINK1/Parkin-associated pathway in this process was examined to provide insights into its contribution to tumor progression. METHODS: APOE in thyroid carcinoma was characterized in terms of its expression profile, diagnostic relevance, and potential biological functions, based on integrative evidence derived from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. APOE and mitophagy-related protein expression were further examined in PTC tissues by immunohistochemistry. Further evaluation of APOE in PTC cell lines focused on its association with proliferation, apoptosis, and mitophagy, with bidirectional functional perturbation serving as the basis for assessment. Pharmacological inhibitors were used to assess the involvement of mitophagy-related signaling in the observed APOE-dependent phenotypes. Additionally, the in vivo impact of APOE on PTC tumor growth and mitophagy was further investigated through a nude mouse xenograft model, providing insight into its potential role in tumor progression. RESULTS: A significant upregulation of APOE was observed in thyroid carcinoma tissues and PTC cell lines, supporting its potential relevance as a diagnostic biomarker. The modulation of APOE expression significantly influenced PTC cell proliferation and apoptosis, with overexpression promoting cell proliferation and inhibiting apoptosis, while knockdown led to the opposite effects. Mechanistically, APOE overexpression increased AMP-activated protein kinase (AMPK) phosphorylation and decreased mammalian target of rapamycin (mTOR) phosphorylation, accompanied by increased PINK1 and Parkin expression and mitophagy-related changes, including altered mitochondrial membrane potential, reduced overall reactive oxygen species levels, and increased autophagosome formation. Pharmacological inhibition of mitophagy attenuated the proliferative and antiapoptotic effects of APOE. CONCLUSIONS: These findings demonstrate that APOE promotes PTC progression in association with PINK1/Parkin-related mitophagy and modulation of the AMPK/mTOR axis. The APOE-associated mitophagy axis may provide a rationale for future preclinical investigation in PTC.

Apolipoprotein E (APOE)↗
PubMed2026

Apolipoprotein E Alleles Across the Spectrum of Frontotemporal Lobar Degeneration: A Systematic Review and Meta-Analysis.

We conducted a systematic review and meta-analysis of associations between apolipoprotein E (APOE) alleles and frontotemporal lobar degeneration (FTLD)-spectrum disorders. MEDLINE, Embase, CENTRAL, and Google Scholar were searched. APOE2 and APOE4 carrier status were compared between FTLD-spectrum disorders and healthy controls (HCs) or individuals with Alzheimer's disease (AD). Forty studies were included. APOE4 carriage was more frequent in frontotemporal dementia (FTD) compared with HC (OR = 1.72; 95% CI = 1.45-2.04) and less common than in AD (OR = 0.35; 95% CI = 0.29-0.42). In contrast, APOE2 carriage was less prevalent in FTD relative to HC (OR = 0.83; 95% CI = 0.70-0.98) but more frequent compared with AD (OR = 1.80; 95% CI = 1.29-2.52). APOE4 effects were most pronounced in behavioral variant FTD. In clinically confirmed progressive supranuclear palsy (PSP), APOE4 carriage was not associated with PSP. Analysis restricted to pathologically confirmed PSP cases, however, showed lower APOE4 carriage in PSP than in healthy controls (OR = 0.78, 95% CI = 0.65-0.94), although this association failed to reach the multiplicity-adjusted significance threshold. APOE2 carriage was not associated with PSP in either clinically established or pathologically confirmed samples. Evidence was insufficient to establish or exclude associations for other FTLD-spectrum disorders because of the limited available data. In conclusion, APOE alleles show distinct associations across the FTLD spectrum.

Humans↗
PubMed1978

Polymorphism of apolipoprotein E. I. Methodological aspects and diagnosis of hyperlipoproteinemia type III without ultracentrifugation.

Two methods for phenotyping apolipoprotein E are compared. One is based on preparation of VLDL by conventional ultracentrifugation, whereas the other uses heparin/Mg precipitation of VLDG. In principle, the same results were obtained by both methods. However, the group limits for the three different phenotypes Apo E-N, Apo E-ND and Apo E-D were slightly different by the two methods. Phenotype Apo E-D - the phenotype characterizing type III dyslipoproteinemia - is clearly definable by both methods. Hence the precipitation-I.E.F. method for Apo E phenotyping provides a simple tool for genetic and population genetic studies and also for the routine diagnosis of hyperlipoproteinemia type III, based on the only specific marker known for this disease.

Apolipoproteins↗
PubMed1978

The levels of apolipoprotein-E in hypercholesterolemic rat serum.

The levels of apolipoprotein-C (apo-E) in serum and isolated liproproteins from diet-induced hypercholesterolemic, and to some extent hypertriglycerdemic rats were measured by electroimmunoassay. The hypocholesterolemia was accompanied by a mild hypertriglyceridemia. The apo-E was increased by 60% in the hypercholesterolemic serum with a 5- and 50-fold increase in very low density lipoproteins (VLDL) and low density lipoproteins (LDL) respectively. However, the proportion of apo-E in nascent VLDL isolated from the hepatic Golgi apparatus of hypercholesterolemic rats was significantly decreased. In control serum, 40--50% of the apo-E is found in the density greater than 1.21 g/ml fraction, although this is at least partially due to ultracentrifugation. The aproprotein is absent from the density greater than 1.21 g/ml fraction from hypercholesterolemic serum, suggesting that it is bound more firmly to the lipoprotein complex. It is concluded that the large increases in apo-E in the VLDL and LDL density ranges of serum from hypercholesterolemic rats may in part be accounted for by the utilization of apo-E normally found at higher densities.

Amino Acids↗
PubMed1979

Polymorphism of apolipoprotein E. III. Effect of a single polymorphic gene locus on plasma lipid levels in man.

The two autosomal codominant alleles of the Apo E-N/D polymorphism, Apo En and Apo Ed, have a considerable influence on plasma lipid levels and distribution in man. Serum cholesterol levels are highest in phenotype Apo E-N, intermediate in phenotype Apo E-ND, and low in phenotype Apo E-D. Contrary VLDL-cholesterol is highest in phenotype Apo E-D, intermediate in heterozygotes, and lowest in phenotype Apo E-N. Serum-triglyceride, VLDL-triglyceride and the ratio of VLDL-cholesterol/serum-triglyceride are also intermediate in phenotype Apo E-ND between the two opposite homozygous groups. 10% of heterozygous Apo E-ND subjects exhibited a beta-VLDL subfraction compared to 0.8% in phenotype Apo E-N and 100% in Apo E-D. Hence the three phenotypic groups exhibit metabolic differences in vivo, and the gene Apo Ed has a mild dyslipoproteinemic effect even in a single dose. The Apo E-N/D polymorphism may therefore be a major influence on the occurrence of arteriosclerotic vascular disease in man.

Adult↗
PubMed1975

Isolation and partial characterization of an arginine-rich apolipoprotein from human plasma very-low-density lipoproteins: apolipoprotein E.

A water-insoluble apoprotein was isolated from apo-VLDL by column chromatography on Sephadex G-200 in sodium dodecylsulfate followed by preparative polyacrylamide gel electrophoresis in a discontinous sodium dodecylsulfate system, or by preparative electrophoresis alone. The protein was similar in amino acid composition to the "arginine-rich protein" reported by Shore and Shore. It represented about 10% of the total protein mass of VLDL. The apoprotein showed one single band with an apparent Mr of 39000 in sodium dodecylsulfate gel electrophoresis, and was homogeneous in gel electrophoresis at pH 8.9 In 8M urea. Immunochemical studies also showed homogeneity of this protein, and antisera prepared against it did not react with any other of the well known apolipoproteins, but did react with VLDL and apo-VLDL preparations. Analytical isoelectric focusing in 8M urea resulted in a heterogeneous banding pattern showing three major polypeptides with pI values of 5.5, 5.6 and 5.75. Thus this apolipoprotein clearly differs from the apo-B and apo-C polypeptides of VLDL as well as from apoproteins A and D in its molecular weight, amino acid composition, focusing behavior and immunochemical properties.

Amino Acids↗
PubMed2024

Uncovering the health implications of abandoned mines through protein profiling of local residents.

Residents in areas with abandoned mines risk significant exposure to abundant heavy metals in the environment. However, current clinical indicators cannot fully reflect the health changes associated with abandoned mine exposure. The aim of this study was to identify biological changes in the residents of abandoned mine areas via proteomic analysis of their blood. Blood samples were collected from abandoned mine and control areas, and mass spectrometry was used for protein profiling. A total of 138 unique or common proteins that were differentially expressed in low-exposure abandoned mine area (LoAMA) or high-exposure abandoned mine area (HiAMA) compared to non-exposure control area (NEA) were analyzed, and identified 4 clusters based on functional similarity. Among the 10 proteins that showed specific change in LoAMA, 4 proteins(Apolipoprotein M, Apolipoprotein E, Apolipoprotein L1, and Cholesteryl ester transfer protein) were cluded in cluster 1(plasma lipoprotein remodeling), and linked to proteins that showed specific change in protein expression in HiAMA. Therefore, it is suggested that 4 proteins are changed at low exposure to an abandoned mine (or initial exposure), and then at high exposure, changes in various proteins involved in linked plasma lipoprotein remodeling are induced, which might triggered by the 4 proteins. Interestingly, in addition to plasma lipoprotein remodeling, proteins involved in other functional networks were changed in the high exposure group. These were all directly or indirectly linked to the 4 biomarkers(Apolipoprotein M, Apolipoprotein E, Apolipoprotein L1, and Cholesteryl ester transfer protein) that changed during low exposure. This suggests their potential utility in identifying areas impacted by abandoned mines. Especially, proteins involved in lipid metabolism and renal function-related diseases in individuals exposed to heavy metals in abandoned mine areas were correlated. Chronic kidney disease is predominantly instigated by cardiovascular disease and is commonly accompanied by dyslipidemia.

Humans↗
PubMed2024

Association of common and rare variants with Alzheimer's disease in more than 13,000 diverse individuals with whole-genome sequencing from the Alzheimer's Disease Sequencing Project.

INTRODUCTION: Alzheimer's disease (AD) is a common disorder of the elderly that is both highly heritable and genetically heterogeneous. METHODS: We investigated the association of AD with both common variants and aggregates of rare coding and non-coding variants in 13,371 individuals of diverse ancestry with whole genome sequencing (WGS) data. RESULTS: Pooled-population analyses of all individuals identified genetic variants at apolipoprotein E (APOE) and BIN1 associated with AD (p&#xa0;<&#xa0;5&#xa0;&#xd7;&#xa0;10-8). Subgroup-specific analyses identified a haplotype on chromosome 14 including PSEN1 associated with AD in Hispanics, further supported by aggregate testing of rare coding and non-coding variants in the region. Common variants in LINC00320 were observed associated with AD in Black individuals (p&#xa0;=&#xa0;1.9&#xa0;&#xd7;&#xa0;10-9). Finally, we observed rare non-coding variants in the promoter of TOMM40 distinct of APOE in pooled-population analyses (p&#xa0;=&#xa0;7.2&#xa0;&#xd7;&#xa0;10-8). DISCUSSION: We observed that complementary pooled-population and subgroup-specific analyses offered unique insights into the genetic architecture of AD. HIGHLIGHTS: We determine the association of genetic variants with Alzheimer's disease (AD) using 13,371 individuals of diverse ancestry with whole genome sequencing (WGS) data. We identified genetic variants at apolipoprotein E (APOE), BIN1, PSEN1, and LINC00320 associated with AD. We observed rare non-coding variants in the promoter of TOMM40 distinct of APOE.

Humans↗
PubMed2024

Sex and APOE &#x3b5;4 allele differences in longitudinal white matter microstructure in multiple cohorts of aging and Alzheimer's disease.

INTRODUCTION: The effects of sex and apolipoprotein E (APOE)-Alzheimer's disease (AD) risk factors-on white matter microstructure are not well characterized. METHODS: Diffusion magnetic resonance imaging data from nine well-established longitudinal cohorts of aging were free water (FW)-corrected and harmonized. This dataset included 4741 participants (age&#xa0;=&#xa0;73.06&#xa0;&#xb1;&#xa0;9.75) with 9671 imaging sessions over time. FW and FW-corrected fractional anisotropy (FAFWcorr) were used to assess differences in white matter microstructure by sex and APOE &#x3b5;4 carrier status. RESULTS: Sex differences in FAFWcorr in projection tracts and APOE &#x3b5;4 differences in FW limbic and occipital transcallosal tracts were most pronounced. DISCUSSION: There are prominent differences in white matter microstructure by sex and APOE &#x3b5;4 carrier status. This work adds to our understanding of disparities in AD. Additional work to understand the etiology of these differences is warranted. HIGHLIGHTS: Sex and apolipoprotein E (APOE) &#x3b5;4 carrier status relate to white matter microstructural integrity. Females generally have lower free water-corrected fractional anisotropy compared to males. APOE &#x3b5;4 carriers tended to have higher free water than non-carriers.

Humans↗
PubMed2026

TCGA-based identification of prognostic biomarkers and candidate traditional Chinese medicine compounds in papillary thyroid carcinoma: An observational study.

This study aimed to identify prognostic genes associated with papillary thyroid carcinoma (PTC) and explore candidate traditional Chinese medicine (TCM) compounds using integrated bioinformatics and molecular docking. In this observational study, PTC gene expression profiles and clinical data were obtained from The Cancer Genome Atlas. Differentially expressed genes were screened using differential-expression sequencing (DESeq2), followed by protein-protein interaction network analysis to identify hub genes. Their expression, diagnostic value, immune relevance, prognostic significance, protein-level validation, and single-cell distribution were assessed using gene expression profiling interactive analysis, receiver operating characteristic analysis, immune infiltration analysis, Kaplan-Meier survival analysis, the human protein atlas, and single-cell RNA-sequencing data. Candidate TCM compounds were predicted using symptom mapping (SymMap) and the TCM Systems Pharmacology Database and Analysis Platform, and molecular docking was performed to evaluate potential ligand-target interactions. Five hub genes, colony-stimulating factor 2, apolipoprotein E, fibronectin 1 (FN1), collagen type I alpha 1 chain (COL1A1), and intercellular adhesion molecule 1, were identified and found to be significantly upregulated in PTC tissues, with diagnostic value in receiver operating characteristic analysis. Immune infiltration analysis showed associations with macrophages, dendritic cells, and T helper 1 cells, whereas single-cell analysis demonstrated heterogeneous expression across immune and stromal cell populations, including fibroblasts. Higher FN1 and COL1A1 expression was associated with poorer outcomes. Immunohistochemistry supported the expression patterns, while single-cell analysis provided exploratory cell-type-level context for the cellular distribution of selected genes. Ginseng and Smilax glabra were predicted as common candidate TCMs, and docking suggested favorable binding between their active compounds and selected hub targets. Colony-stimulating factor 2, apolipoprotein E, FN1, COL1A1, and intercellular adhesion molecule 1 may be biologically relevant hub genes in PTC, while FN1 and COL1A1 may have prognostic value. Predicted TCM compounds provide preliminary computational evidence for possible compound-target interactions, requiring experimental and clinical validation.

Female↗