Relationships between APOE, Type 2 Diabetes, and Cardiovascular Disease in Postmenopausal Women.

BACKGROUND: The Apolipoprotein E (APOE) ε4 allele, type 2 diabetes mellitus (T2DM), and cardiovascular disease (CVD) are well-established risk factors for dementia. Relationships between APOE and incidence of T2DM and CVD are not fully understood but may shed light on the mechanisms underlying dementia pathogenesis. METHODS: Postmenopausal women (N=6,795) from the Women's Health Initiative hormone therapy clinical trial with APOE genotyping and no prior diagnosis of T2DM or CVD were included. We examined associations of APOE status (APOE2+ [ε2/ε2, ε2/ε3], APOE3 [ε3/ε3], and APOE4+ [ε4/ε4, ε3/ε4] carriers) with incidence of T2DM, coronary heart disease (CHD), stroke, and total CVD events using Cox regression. CVD outcomes were examined in baseline non-statin users and adjusted for statin initiation over follow-up to account for possible confounding by statins. RESULTS: Among all participants (mean age 66.7±6.5 years, 100% non-Hispanic white), 451 (6.6%) were using statins at baseline. Over the follow-up (mean 14.9 and 16.0 years for T2DM and CVD, respectively), 1,564 participants developed T2DM and 1,578 developed CVD. T2DM incidence did not differ significantly by APOE status (ps≥0.09). Among non-statin users, APOE4+ had higher incidence of total CVD (hazard ratio [95% confidence interval]=1.18 [1.02-1.38], p=0.03) compared to APOE3 carriers, but risks for CHD (1.09 [0.87-1.36], p=0.47) and stroke (1.14 [0.91-1.44], p=0.27) were not significantly elevated when examined individually. CVD outcomes did not differ between APOE2+ and APOE3 carriers (ps≥0.11). CONCLUSIONS: T2DM risk did not differ by APOE status among postmenopausal women, but APOE4+ carriers not using statins had an increased risk of total CVD events.

The efficacy and safety of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors combined with statins in patients with hypercholesterolemia: a network meta-analysis.

Background: In recent years, the position of PCSK9 inhibitors as adjuvant therapy to statins in guidelines has further improved. However, there remained a dearth of direct comparative studies among different PCSK9 inhibitors. Therefore, this study aimed to conduct a network meta-analysis to evaluate the efficacy and safety of different PCSK9 inhibitors combined with statins. Methods: A comprehensive literature search was conducted from the study's inception to 12 November 2023, encompassing multiple online databases including PubMed, Embase, Cochrane Central, Web of Science, and ClinicalTrials.gov to obtain relevant randomized controlled trials. Frequentist network meta-analysis was employed to compare the efficacy and safety of different PCSK9 inhibitors. The efficacy endpoints were low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (ApoB), and lipoprotein (a) (Lp(a)). The safety endpoints were any adverse events (AE), severe adverse events (SAE), AE leading to treatment discontinuation, and injection-site reaction. Results: Compared with placebo and ezetimibe, all PCSK9 inhibitors demonstrated significant reductions in LDL-C levels. Notably, evolocumab exhibited the most pronounced effect with a treatment difference of -63.67% (-68.47% to -58.87%) compared with placebo. Regarding dosage selection for evolocumab, the regimen of 140 mg Q2W (-69.13%, -74.55% to -63.72%) was superior to 420 mg QM (-61.51%, -65.97% to -57.05%). Based on rankings and P-scores analysis, tafolecimab 150 mg Q2W demonstrated superior efficacy in reducing ApoB levels (-61.70%, -84.38% to -39.02%) and Lp(a) levels (-43%, 30%, -68%, 81% to -17%, 79%). Furthermore, the safety profile of PCSK9 inhibitors was favorable with no increase in the incidence of AE, SAE, or AE leading to treatment discontinuation; however, alirocumab, inclisiran, and tafolecimab may potentially entail a potential risk associated with injection-site reactions. Conclusion: Compared with placebo and ezetimibe, PCSK9 inhibitors can significantly reduce LDL-C, ApoB, and Lp(a) when combined with statins to treat hypercholesterolemia. Furthermore, PCSK9 inhibitors and ezetimibe exhibit similar safety profiles. Systematic Review Registration: [PROSPERO], identifier [CRD42023490506].

iPSC-derived blood-brain barrier modeling reveals APOE isoform-dependent interactions with amyloid beta.

BACKGROUND: Three common isoforms of the apolipoprotein E (APOE) gene - APOE2, APOE3, and APOE4 - hold varying significance in Alzheimer's Disease (AD) risk. The APOE4 allele is the strongest known genetic risk factor for late-onset Alzheimer's Disease (AD), and its expression has been shown to correlate with increased central nervous system (CNS) amyloid deposition and accelerated neurodegeneration. Conversely, APOE2 is associated with reduced AD risk and lower CNS amyloid burden. Recent clinical data have suggested that increased blood-brain barrier (BBB) leakage is commonly observed among AD patients and APOE4 carriers. However, it remains unclear how different APOE isoforms may impact AD-related pathologies at the BBB. METHODS: To explore potential impacts of APOE genotypes on BBB properties and BBB interactions with amyloid beta, we differentiated isogenic human induced pluripotent stem cell (iPSC) lines with different APOE genotypes into both brain microvascular endothelial cell-like cells (BMEC-like cells) and brain pericyte-like cells. We then compared the effect of different APOE isoforms on BBB-related and AD-related phenotypes. Statistical significance was determined via ANOVA with Tukey's post hoc testing as appropriate. RESULTS: Isogenic BMEC-like cells with different APOE genotypes had similar trans-endothelial electrical resistance, tight junction integrity and efflux transporter gene expression. However, recombinant APOE4 protein significantly impeded the "brain-to-blood" amyloid beta 1-40 (Aß40) transport capabilities of BMEC-like cells, suggesting a role in diminished amyloid clearance. Conversely, APOE2 increased amyloid beta 1-42 (Aß42) transport in the model. Furthermore, we demonstrated that APOE-mediated amyloid transport by BMEC-like cells is dependent on LRP1 and p-glycoprotein pathways, mirroring in vivo findings. Pericyte-like cells exhibited similar APOE secretion levels across genotypes, yet APOE4 pericyte-like cells showed heightened extracellular amyloid deposition, while APOE2 pericyte-like cells displayed the least amyloid deposition, an observation in line with vascular pathologies in AD patients. CONCLUSIONS: While APOE genotype did not directly impact general BMEC or pericyte properties, APOE4 exacerbated amyloid clearance and deposition at the model BBB. Conversely, APOE2 demonstrated a potentially protective role by increasing amyloid transport and decreasing deposition. Our findings highlight that iPSC-derived BBB models can potentially capture amyloid pathologies at the BBB, motivating further development of such in vitro models in AD modeling and drug development.

The relationship between early-onset coronary artery disease and familial hypercholesterolemia: a cohort study based on the Hakka population in Meizhou, China.

BACKGROUND: The low diagnosis and treatment rates of familial hypercholesterolemia (FH) have become a global issue. This study aims to explore the correlation between early-onset coronary artery disease (CAD) and FH in the Hakka population in Meizhou, Guangdong. METHODS: Clinical data of Hakka patients with early-onset CAD, admitted to the Meizhou People's Hospital from January 2023 to January 2024 were retrospectively analyzed. The patients were categorized into an FH group and a non-FH group. Biochemical indicators, lipid levels, echocardiographic parameters, clinical phenotypes, and genetic typing of early-onset CAD patients in the Hakka population were analyzed for their correlation with FH. RESULTS: A total of 167 Hakka patients with early-onset CAD were included, among whom 22 patients had FH. The FH group showed lower triglyceride (TG) level [1.785 (1.40, 2.10) vs. 2.090 (1.80, 2.30), P = 0.002] and higher levels of total cholesterol (TC) [6.635 (5.60, 7.10) vs. 4.830 (4.00, 5.40), P<0.001], low-density lipoprotein cholesterol (LDL-C) [4.440 (3.90, 5.20) vs. 2.820 (2.40, 3.30), P<0.001], and apolipoprotein B (Apo B) [1.600 (1.30, 1.80) vs. 0.910 (0.70, 1.10), P<0.001]. FH was correlated with TG, TC, LDL-C and Apo B levels (r1 = -0.235; r2 = 0.441; r3 = 0.483; r4 = 0.538). TG is a risk factor while TC, LDL-C and Apo B are protective factors for FH. CONCLUSION: The incidence of FH is relatively high among early-onset CAD patients in the Hakka population in Meizhou. TG, TC, LDL-C, and Apo B levels are valuable in aiding clinical differential diagnosis of CAD patients with FH.

Apolipoprotein A-I Mimetic Peptide Restores VEGF-induced Angiogenesis in Hypercholesterolemic Ischemic Heart by Reducing HDL Proinflammatory Properties.

VEGF-induced angiogenesis is impaired in hypercholesterolemia. Previous studies showed that an apolipoprotein A-I(ApoA-I) mimetic peptide, D-4F, is able to reduce HDL proinflammatory index in hypercholesterolemia. Whether D-4F promotes angiogenesis in hypercholesterolemia remains unclear. Low-density lipoprotein receptor null (LDLr-/-) mice and LDLr-/-/ApoA-I-/- mice were fed with high-fat diet with or without D-4F (1mg/kg·d). C57BL/6 mice fed with normal diet served as control. The myocardial infarction was induced by ligation coronary artery, and the VEGFA-AAV 9 was injected in heart. The plasma HDL proinflammatory index, cardiac function, infarct size, and angiogenesis related signaling pathways were examined. The HDL proinflammatory index increases in hypercholesterolemic mice. VEGFA stimulates angiogenesis and improves cardiac function in ischemic heart of C57BL/6 mice, but not in hypercholesterolemic mice. D-4F reduces HDL proinflammatory index. D-4F combined with VEGFA stimulates the expression of CD31 and eNOS, activates ERK1/2, reduces infarct size, and improves cardiac function in ischemic heart in hypercholesterolemic LDLr-/- mice but not in hypercholesterolemic LDLr-/-/ApoA-I-/- mice. D-4F restores the VEGF-induced angiogenesis by reducing HDL proinflammatory properties in hypercholesterolemic ischemic heart.

Effects of APOE isoforms in diabetic nephropathy patients of South India.

BACKGROUND: Diabetic nephropathy (DN) is a grave complication and the most common renal dysfunction of diabetes mellitus. Genetic factors, including Apolipoprotein E (APOE) isoforms, have been implicated in the pathogenesis of DN. METHODS: A total of 577 type 2 Diabetes mellitus subjects were categorized into diabetes non-nephropathic (Controls: n = 321), diabetes nephropathic (DN: n = 256) groups. Demographic, clinical, and biochemical parameters including age, BMI, lipid profiles (TC, LDL-C, HDL-C, TG), glucose metabolism (plasma glucose, HbA1c, serum insulin), renal function (UACR, PCR), and blood pressure (SBP, DBP) were assessed. APOE variant frequencies were determined using restriction fragment length polymorphism (RFLP) analysis, validated against Hardy-Weinberg equilibrium (HWE), and statistically correlated with each clinical and biochemical parameter. RESULTS: The DN group had an increased prevalence of hypertension, fatty liver, and dyslipidemia compared to the Control group. Biochemical analyses revealed elevated levels of TC (213.41 mg/dL vs. 189.32 mg/dL), LDL-C (134.46 mg/dL vs. 107.56 mg/dL), and reduced HDL-C (58.13 mg/dL vs. 65.32 mg/dL) in DN cases compared to Controls (all p < 0.0001). The APOE variants distribution showed a significant increase in E2 allele frequency (69.1% vs. 15.3%) and corresponding homozygous genotype (E2/2: 42.2% vs. 5.6%) in DN cohorts. CONCLUSION: The study found a higher frequency of E2 allele in the DN group compared to Controls, though no statistically significant risk of DN was linked to this allele. The results suggest a potential association for APOE polymorphisms, requiring broader studies to clarify the role of APOE polymorphisms in DN susceptibility.

Exploring complexities of Alzheimer's disease: New insights into molecular and cellular mechanisms of neurodegeneration and targeted therapeutic interventions.

Alzheimer's disease (AD), the common form of dementia globally, is a complex condition including neurodegeneration; shares incompletely known pathogenesis. Signal transduction and biological activities, including cell metabolism, growth, and death are regulated by different signaling pathways including AKT/MAPK, Wnt, Leptin, mTOR, ubiquitin, Sirt1, and insulin. Absolute evidence linking specific molecular pathways with the genesis and/or progression of AD is still lacking. Changes in gut microbiota and blood-brain barrier also cause amyloid ß aggregation in AD. The current review reports significant characteristics of various signaling pathways, their relationship with each other, and how they interact in disease genesis and/or progression. Nevertheless, due to the enormous complexity of the brain and numerous chemical linkages between these pathways, the use of signaling pathways as possible targets for drug development against AD is minimal. Currently, there is no permanent cure for AD, and there is no way to stop brain cell loss. This review also aimed to draw attention to the role of a novel group of signaling pathways, which can be collectively dubbed "anti-AD pathways", in multi-target therapy for AD, where cellular metabolic functions are severely impaired. Thus, different hypotheses have been formulated and elaborated to explain the genesis of AD, which can be further explored for drug development too.

A Comparative Analysis of Low-Density Lipoprotein Cholesterol (LDL-C)-Lowering Activities of Bempedoic Acid, Inclisiran, and PCSK9 Inhibitors: A Systematic Review.

Newer drugs, such as bempedoic acid, inclisiran, alirocumab, and evolocumab have recently been introduced for dyslipidemia. This systematic review aims to perform a comparative analysis of these drugs' low-density lipoprotein cholesterol (LDL-C)-lowering activities. The PubMed database was utilized to search for randomized controlled trials. Articles were screened and selected based on specific inclusion and exclusion criteria. The primary outcome of this review is to compare the percentage reduction of LDL-C and apolipoprotein-B, along with the number of reported serious adverse events (SAEs) in trials specific to each drug. A total of 14 studies were included, four for bempedoic acid and alirocumab and three for evolocumab and inclisiran. The maximum percentage reduction in LDL-C and apolipoprotein-B from baseline to 12 weeks was observed with alirocumab, administered at 150 mg subcutaneously twice weekly for 12 weeks, achieving reductions of 72.4% and 57.9%, respectively. Lesser reductions were observed with bempedoic acid, administered at 180 mg once daily orally for 12 weeks. The highest number of SAEs were reported with bempedoic acid (216, 10%) and inclisiran (181, 11%; 175, 11%). This systematic review showed that alirocumab achieved the greatest reductions in LDL-C and apolipoprotein-B and a better safety profile. Newer LDL-C-lowering drugs show promise in improving lipid profiles, patient compliance, and safety. However, these findings are not conclusive, as other factors also influence treatment choice.

Apolipoprotein C-III in association with metabolic-dysfunction associated steatotic liver disease: A large, multicenter study.

BACKGROUND & AIMS: The available literature on the effect of apolipoprotein C-III (ApoC-III) inhibition in MASLD reveals inconsistencies. The aim of the present work was to examine levels of ApoC-III in the entire spectrum of metabolic-dysfunction associated steatotic liver disease (MASLD). METHODS: This is a multicenter study involving patients enrolled in two gastroenterology-hepatology clinics (Greece and Australia) and in a bariatric-metabolic surgery clinic (Italy), with liver biopsy before and after bariatric surgery or lifestyle modification. RESULTS: Comparing simple MASL to steatohepatitis (MASH) with fibrosis stage F ≥ 2 (at-risk MASH), revealed a marginally significant trend for decreased ApoC-III levels in the latter group (p = 0.07). Multi-adjusted analysis revealed an inverse association between ApoC-III and at-risk MASH (Odds Ratioper 1 mg/dL increase in ApoC-III = 0.91, 95 % Confidence Interval (0.83, 0.99)). ApoC-III interacted with triglycerides in predicting at-risk MASH (p-for-interaction = 0.002). Participants with ApoC-III > median (∼3.75 mg/dL) and normal triglycerides (triglyceridese≤150 mg/dL) had the lowest likelihood to present at-risk MASH (31.8 %) in contrast with participants with ApoC-III < median and hypertriglyceridemia among whom at-risk MASH was recorded in 57.1 %. In multi-adjusted analysis participants with normal triglycerides and high ApoC-III had 64 % lower odds of at-risk MASH compared with their counterparts with ApoC-III < median (OR = 0.36, 95%CI (0.14, 0.86)). Among participants with hypertriglyceridemia, those with ApoC-III < median had less prevalent at-risk MASH compared with those with ApoC-III ≥ median (OR = 0.54, 95%CI (0.32, 0.98)); however in all cases significance was lost when liver enzymes were taken into account. CONCLUSIONS: In advanced disease stages, ApoC-III levels seem to be decreased and advanced organ damage may be a potential explanation. Mendelian randomization studies are needed to confirm or refute this hypothesis.

Revisiting high-density lipoprotein cholesterol in cardiovascular disease: Is too much of a good thing always a good thing?

Cardiovascular disease (CVD) continues to be a leading cause of global mortality and morbidity. Various established risk factors are linked to CVD, and modifying these risk factors is fundamental in CVD management. Clinical studies underscore the association between dyslipidemia and CVD, and therapeutic interventions that target low-density lipoprotein cholesterol elicit clear benefits. Despite the correlation between low high-density lipoprotein cholesterol (HDLC) and heightened CVD risk, HDL-raising therapies have yet to showcase significant clinical benefits. Furthermore, evidence from epidemiological and genetic studies reveals that not only low HDL-C levels, but also very high levels of HDL-C are linked to increased risk of CVD. In this review, we focus on HDL metabolism and delve into the relationship between HDL and CVD, exploring HDL functions and the observed alterations in its roles in disease. Altogether, the results discussed herein support the conventional wisdom that "too much of a good thing is not always a good thing". Thus, our recommendation is that a careful reconsideration of the impact of high HDL-C levels is warranted, and shall be revisited in future research.

Associations of combined accelerated biological aging and genetic susceptibility with incident dementia: a prospective study in the UK Biobank.

BACKGROUND: Accelerated biological aging has been verified to be a critical risk factor for a number of age-related diseases, but its role in dementia remained unclear. Whether it modified the effects of genetic factors was also unknown. This study evaluated the associations between accelerated biological aging and dementia and the moderating role of accelerated biological aging in the genetic susceptibility to the disease. METHODS: We included 200,731 participants in the UK biobank. Nine clinical blood biomarkers and chronological age were used to calculate Phenotypic age acceleration (PhenoAgeAccel), which is a novel indicator for accelerated biological aging. The associations of PhenoAgeAccel with dementia, both young-onset and late-onset dementia, were assessed by Cox proportional hazard models. Apolipoprotein E (APOE) alleles and polygenic risk scores (PRS) were used to evaluate the genetic risk of dementia. The interactions between genetic susceptibility and biological aging were tested on both multiplicative and additive scales. RESULTS: These findings showed individuals who were in the highest quartile of PhenoAgeAccel had a higher risk with incidence of dementia compared to individuals in the lowest quartile of PhenoAgeAccel (HR: 1.145 (95% CI: 1.050, 1.249)). Individuals with biologically older had a higher risk of dementia than individuals with biologically younger (HR: 1.069 (95% CI: 1.004, 1.138)). Furthermore, compared to individuals with biologically younger and low APOE ε4-related genetic risk, individuals with biologically younger and high APOE ε4-related genetic risk (HR:3.048 (95% CI: 2.811, 3.305)) had a higher risk of dementia than individuals with biologically older and high APOE ε4-related genetic risk (HR: 2.765 (95% CI: 2.523, 3.029)). Meanwhile, referring to low dementia PRS and biologically younger, the risk of dementia increased by 72.7% (HR: 1.727 (95% CI: 1.538, 1.939) in the biologically younger and high PRS group and 58.7% (HR: 1.587 (95% CI: 1.404, 1.793) in the biologically older and high PRS group, respectively. The negative interactions between PhenoAgeAccel with APOE ε4 and PRS were also tested on the additive scale. CONCLUSIONS: Accelerated biological aging could bring the extra risk of dementia but attenuate the effects of genetic risk on dementia. These findings provide insights for precise prevention and intervention of dementia.

Exploring the causal effects of serum lipids and lipidomes on lewy body dementia: a Mendelian randomization study.

Background: Lewy body dementia (LBD) is a neurodegenerative disorder characterized by the accumulation of Lewy bodies, which primarily composed of misfolded alpha-synuclein (αS). The development of LBD and APOE4 subtypes is thought to be associated with disorders of lipid metabolism. In this study, we investigated the causal relationship between serum lipids, liposomes and LBD using a two-sample Mendelian randomization (TSMR) method. Methods: A TSMR analysis of genome-wide association study (GWAS) data for 8 serum lipids, 179 lipidomes components, LBD and its subtypes was performed, using inverse variance weighted as the primary outcome. To ensure robustness, the sensitivity analyses including MR Pleiotropy RESidual Sum and Outlier, Cochran's test, leave-one-out method and funnel plots were performed. Results: In this study, we found that low-density lipoprotein cholesterol (LDL-C) (OR=1.45, 95% CI=1.19-1.77, P<0.001) and remnant cholesterol (RC) (OR=2.64, 95% CI=1.64-4.28, P<0.001) had significant positive causal effects on LBD, and RC also had a positive effect on LBD in carriers of the APOE4 gene. The results of lipidome analysis showed that phosphatidylcholine (PC) (O-16:0_20:4) levels (OR=0.86, 95% CI=0.75-0.98, P=0.02) and PC (O-18:1_20:4) levels (OR=0.76, 95% CI=0.65-0.89, P <0.001) had negative causal effects on LBD, whereas phosphatidylinositol (PI) (18:1_20:4) levels had a positive causal effect on LBD (OR=1.19, 95% CI=1.02-1.39, P=0.03). For LBD with APOE4 carriers, high levels of PC (16:1_18:0) and PC (O-18:2_18:1) had a significant positive effect, while high levels of PC (O-16:1_18:0), phosphatidylethanolamine (PE) (O-18:2_18:1), sphingomyelin (SM) (d38:2), and triacylglycerol (TAG) (56:5) significantly reduced the risk. No heterogeneity and horizontal pleiotropy were observed in sensitivity analysis. Conclusion: Elevated LDL-C and RC levels are significant risk factors for LBD, with RC also impacting APOE4-carrying LBD. Glycerophospholipids play a crucial role in the pathogenesis of LBD, but the specific components that play a role differ from those with the APOE4 carries. These findings highlight the importance of lipid metabolism in LBD and APOE4 subtypes.

Integrated bioinformatics reveals genetic links between visceral obesity and uterine tumors.

Visceral obesity (VO), characterized by excess fat around internal organs, is a recognized risk factor for gynecological tumors, including benign uterine leiomyoma (ULM) and malignant uterine leiomyosarcoma (ULS). Despite this association, the shared molecular mechanisms remain underexplored. This study utilizes an integrated bioinformatics approach to elucidate common molecular pathways and identify potential therapeutic targets linking VO, ULM, and ULS. We analyzed gene expression datasets from the Gene Expression Omnibus (GEO) to identify differentially expressed genes (DEGs) in each condition. We found 101, 145, and 18 DEGs in VO, ULM, and ULS, respectively, with 37 genes overlapping across all three conditions. Functional enrichment analysis revealed that these overlapping DEGs were significantly enriched in pathways related to cell proliferation, immune response, and transcriptional regulation, suggesting shared biological processes. Protein-protein interaction network analysis identified 14 hub genes, of which TOP2A, APOE, and TYMS showed significant differential expression across all three conditions. Drug-gene interaction analysis identified 26 FDA-approved drugs targeting these hub genes, highlighting potential therapeutic opportunities. In conclusion, this study uncovers shared molecular pathways and actionable drug targets across VO, ULM, and ULS. These findings deepen our understanding of disease etiology and offer promising avenues for drug repurposing. Experimental validation is needed to translate these insights into clinical applications and innovative treatments.

Astrocytes initiate autophagic flux and maintain cell viability after internalizing non-active native extracellular α-synuclein.

Astrocytes are tasked with regulating the synaptic environment. Early stages of various neurodegenerative diseases are characterized by synapse loss, and astrocytic atrophy and dysfunction has been proposed as a possible cause. α-Synuclein (αS) is a highly expressed neuronal protein located in the synapse that can be released in the extracellular space. Evidence points to astrocytes as being responsible for uptake and degradation of extracellular αS. Therefore, misfolded active fibrillized αS resulting in protein inclusions and aggregates could be due to astrocytic dysfunction. Despite these pathological hallmarks and lines of evidence, the autophagic function of astrocytes in response to monomeric non-active αS to model healthy conditions has not been investigated. Human primary cortical astrocytes were treated with 100 nM of extracellular monomeric non-active αS alone, and in combination with N-terminal binding monomeric γ-synuclein (γS) as a control. Western blot analysis and super resolution imaging of HiLyte-488 labeled αS confirmed successful internalization of αS at 12, 24 and 48 h after treatment, while αS dimers were only observed at 48 h. Western blot analysis also confirmed αS's ability to induce autophagic flux by 48 h. Annexin V/PI flow cytometry results revealed increased early apoptosis at 24 h, but which resolved itself by 48 h, indicating no cell death in cortical astrocytes at all time points, suggesting astrocytes can manage the protein degradation demand of monomeric αS in healthy physiological conditions. Likewise, astrocytes reduced secretion of apolipoprotein (ApoE), a protein involved in pro-inflammatory pathways, synapse regulation, and autophagy by 12 h. Similarly, total c-JUN protein levels, a transcription factor involved in pro-inflammatory pathways increased by 12 h in the nuclear fraction. Therefore, astrocytes are able to respond and degrade αS in healthy physiological conditions, and astrocyte dysfunction could precede detrimental αS accumulation.

Relationship of high-density lipoprotein subfractions and apolipoprotein A-I with fat in the pancreas.

AIM: To investigate the associations of high-density lipoprotein (HDL) subfractions and apolipoprotein A-I (apo A-I) with fat in the pancreas. METHODS: A total of 170 individuals were studied. All participants underwent magnetic resonance imaging on a single 3.0-Tesla scanner to determine the presence/absence of fatty pancreas. HDL subfractions were measured using a commercially available lipoprotein subfractions testing system and classed as large, intermediate and small HDL. Both unadjusted and adjusted (accounting for demographics, anthropometrics, insulin resistance and other covariates) logistic regression models were built. RESULTS: Individuals with fatty pancreas had significantly lower circulating levels of the large HDL class and apo A-I. Every unit decrease in the large HDL class was associated with a 93% increase in the likelihood of fatty pancreas in the most adjusted model (P < .001). Every unit decrease in apo A-I was associated with a 45% increase in the likelihood of fatty pancreas in the most adjusted model (P = .012). The intermediate and small HDL classes were not significantly associated with fatty pancreas. CONCLUSIONS: Fat in the pancreas is inversely associated with the circulating levels of large HDL particles and apo A-I. Purposely designed studies are warranted to investigate the potential of fatty pancreas as an indicator of the risk of cardiovascular diseases.

Role of Apolipoprotein E in Alzheimer's Disease Pathogenesis, Prognosis and Treatment.

Alzheimer's disease (AD) is an incurable and progressive neurodegenerative disease with increasing prevalence worldwide. Previous trials of anti-amyloid and anti-tau immunotherapy indicate that additional research needs to be conducted on other mechanisms to find curative or disease-modifying therapy. This review focuses on apolipoprotein E (ApoE), a critical protein in brain lipid metabolism that acts specifically in the clearance and transport of lipids and cholesterol. The ApoE4 allele confers substantial gene dose-dependent risk of developing AD and lowers the age of onset of AD, although the mechanisms of influence remain incompletely understood. The other isoforms bring different levels of AD risk. ApoE2 is protective while ApoE3 is the most common isoform and is considered neutral. An overview is presented of the latest information on the role of ApoE in AD pathogenesis with an emphasis on pathways that are involved in AD development and interactions with crucial processes in different cell types in the brain. Elucidating the key interactions of ApoE with multiple aspects of brain function can be useful for designing novel ApoE-targeted therapeutic approaches.

Strategies to verify equimolar peptide release in mass spectrometry-based protein quantification exemplified for apolipoprotein(a).

OBJECTIVES: Quantitative protein mass spectrometry (MS) is ideally suited for precision diagnostics and for reference standardization of protein analytes. At the Leiden Apolipoprotein Reference Laboratory we apply MS strategies to obtain detailed insight into the protein-to-peptide conversion in order to verify that quantifier peptides are not partly concealed in miscleaved protein backbone. METHODS: Apolipoprotein(a) (apo(a)) was digested in a non-optimal manner to enhance the number of miscleaved peptides that were identified by high resolution liquid chromatography tandem-MS measurements. The protein-to-peptide conversion was carefully mapped with specific attention for miscleaved peptides that contain an apo(a) quantifier peptide. Four different isotopologues of each apo(a)-quantifier peptide were applied to evaluate linearity of internal peptide standards during measurement of specific real-life samples. RESULTS: Two apo(a) quantifier peptides that were concealed in two different miscleaved peptides were included into a multiple reaction monitoring list in our targeted MS-based apo(a) quantifications to alert for potential protein digestion discrepancies. The presence of miscleaved peptides could be ruled out when applying our candidate reference measurement procedure (RMP) for apo(a) quantification. CONCLUSIONS: These data further corroborate the validity of our apo(a) candidate RMP as higher order method for certification of commercial Lp(a) tests that is endorsed by the International Federation of Clinical Chemistry and Laboratory Medicine. MS-based molecular detection and quantification of heterogeneous apo(a) proteoforms will allow manufacturers' transitioning from confounded lipoprotein(a) [Lp(a)] mass levels into accurate molar apo(a) levels.

Ce-MOF@Au-Based Electrochemical Immunosensor for Apolipoprotein A1 Detection Using Nanobody Technology.

Apolipoprotein A1 (Apo-A1) is a well-recognized biomarker in tissues, closely associated with cardiovascular diseases such as atherosclerosis, coronary artery disease, and heart failure. However, existing methods for Apo-A1 determination are limited by costly equipment and intricate operational procedures. Given the distinct advantages of electrochemical immunosensors, including affordability and high sensitivity, along with the unique attributes of nanobodies (Nbs), such as enhanced specificity and better tissue permeability, we developed an electrochemical immunosensor for Apo-A1 detection utilizing Nb technology. In our study, Ce-MOF@AuNPs nanocomposites were synthesized by using ultrasonic methods and applied to modify a glassy carbon electrode. The Nb6, screened from an Apo-A1 immunized phage library, was immobilized onto the nanocomposite material, establishing a robust binding interaction with Apo-A1. The recorded peak current values demonstrated a logarithmic increase corresponding to Apo-A1 concentrations ranging from 1 to 100,000 pg/mL, with a detection limit of 36 fg/mL. Additionally, the developed immunosensors demonstrated high selectivity, good stability, and reproducibility. Our methodology was also effectively utilized for serum sample analysis, showing good performance in clinical assessments. This electrochemical immunosensor represents a promising tool for Apo-A1 detection, with significant potential for advancing cardiovascular disease diagnostics.

Lipoprotein receptors: A little grease for enveloped viruses to open the lock?

Several studies recently highlighted the role of lipoprotein receptors in viral entry. These receptors are evolutionarily ancient proteins, key for the transport of lipids as well as other signaling molecules across the plasma membrane. Here, we discuss the different families of lipoprotein receptors and how they are hijacked by enveloped viruses to promote their entry into infected cells. While the usage of lipoprotein receptors was known for members of the Flaviviridae family and vesicular stomatitis virus, the last 4 years have seen the discovery that these receptors are used by many genetically unrelated viruses. We also emphasize how viral particles interact with these receptors and the possible targeting of these host factors as antiviral strategies.

Current insights into apolipoprotein E and the immune response in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurological disorder and the most common cause of dementia. Genetic analyses identified apolipoprotein E (APOE) as the strongest genetic risk for late-onset AD. Studies have shown that ApoE modulates AD pathogenesis in part by influencing amyloid-ß (Aß) deposition. However, ApoE also appears to regulate elements of AD via regulation of innate immune response, especially through microglial and astrocyte activation. In model systems, it also regulates changes in T-cells. This review focuses on the key findings that have advanced our understanding of the role of ApoE in the pathogenesis of AD and the current view of innate immune response regulated by ApoE in AD, while discussing open questions and areas for future research.