Human Apolipoprotein Research Articles

Differential and substrate-specific inhibition of γ-secretase by the C-terminal region of ApoE2, ApoE3, and ApoE4

Aberrant low γ-secretase activity is associated with most of the presenilin mutations that underlie familial Alzheimer's disease (fAD). However, the role of γ-secretase in the more prevalent sporadic AD (sAD) remains unaddressed. Here, we report that human apolipoprotein E (ApoE), the most important genetic risk factor of sAD, interacts with γ-secretase and inhibits it with substrate specificity in cell-autonomous manners through its conserved C-terminal region (CT). This ApoE CT-mediated inhibitory activity is differentially compromised in different ApoE isoforms, resulting in an ApoE2>ApoE3>ApoE4 potency rank order inversely correlating to their associated AD risk. Interestingly, in an AD mouse model, neuronal ApoE CT migrates to amyloid plaques in the subiculum from other regions and alleviates the plaque burden. Together, our data reveal a hidden role of ApoE as a γ-secretase inhibitor with substrate specificity and suggest that this precision γ-inhibition by ApoE may protect against the risk of sAD.

The E2 glycoprotein holds key residues for Mayaro virus adaptation to the urban Aedes aegypti mosquito.

Adaptation to mosquito vectors suited for transmission in urban settings is a major driver in the emergence of arboviruses. To better anticipate future emergence events, it is crucial to assess their potential to adapt to new vector hosts. In this work, we used two different experimental evolution approaches to study the adaptation process of an emerging alphavirus, Mayaro virus (MAYV), to Ae. aegypti, an urban mosquito vector of many other arboviruses. We identified E2-T179N as a key mutation increasing MAYV replication in insect cells and enhancing transmission after escaping the midgut of live Ae. aegypti. In contrast, this mutation decreased viral replication and binding in human fibroblasts, a primary cellular target of MAYV in humans. We also showed that MAYV E2-T179N generates reduced viremia and displays less severe tissue pathology in vivo in a mouse model. We found evidence in mouse fibroblasts that MAYV E2-T179N is less dependent on the Mxra8 receptor for replication than WT MAYV. Similarly, exogenous expression of human apolipoprotein receptor 2 and Mxra8 enhanced WT MAYV replication compared to MAYV E2-T179N. When this mutation was introduced in the closely related chikungunya virus, which has caused major outbreaks globally in the past two decades, we observed increased replication in both human and insect cells, suggesting E2 position 179 is an important determinant of alphavirus host-adaptation, although in a virus-specific manner. Collectively, these results indicate that adaptation at the T179 residue in MAYV E2 may result in increased vector competence-but coming at the cost of optimal replication in humans-and may represent a first step towards a future emergence event.

Apolipoprotein E (APOE) Haplotypes in Healthy Subjects from Worldwide Macroareas: A Population Genetics Perspective for Cardiovascular Disease, Neurodegeneration, and Dementia

Human APOE is a 299-amino acid long protein expressed and secreted in several tissues and body districts, where it exerts different functions mainly related to lipid metabolism, with specific activities around cholesterol transport and absorption/elimination. It has three main isoforms, determined by the pair of mutations rs7412-C/T and rs429358-C/T, which gives rise to the functionally different APOE variants ε2, ε3, and ε4. These have a distinct impact on lipid metabolism and are differentially implicated in Alzheimer's disease and neurodegeneration, cardiovascular disease, and dyslipidemia. A plethora of other single nucleotide variants along the sequence of the APOE gene have been studied in cohorts of affected individuals, where they also modulate the influence of the three main isoforms to determine the risk of developing the disease. However, no contextual analysis of gene-long haplotypes has been carried out so far, and never extensively in cohorts of healthy individuals from different worldwide populations. Leveraging a rich population genomics dataset, this study elucidates the distribution of APOE variants and haplotypes that are shared across populations and to specific macroareas, revealing a variety of risk-allele associations that distinguish specific ancestral backgrounds and can be leveraged for specific ancestry-informed screenings in medicine and public health.

Host defense peptides identified in human apolipoprotein B as natural food bio‐preservatives: Evaluation of their biosafety and digestibility

AbstractThe employment of chemical agents in the food industry is raising several concerns by consumers and is leading to an increasing interest in natural food preservatives. Among alternatives, host defense peptides (HDPs) have attracted great interest for their ability to preserve food samples from contamination without altering their quality, taste, and organoleptic properties. Recently, we evaluated the applicability of ApoB‐derived peptides as novel food bio‐preservatives and demonstrated their ability to prevent chicken meat sample contamination when immobilized on chitosan films. To perform a further step towards the applicability of these peptides in the food field, here we evaluated peptides biosafety and digestibility. To do this, we used a multidisciplinary approach including the evaluation of the peptides' toxicity and antimicrobial activity, the analysis of resistance phenotype development, an in silico prediction of the peptides' susceptibility to proteases and the evaluation of the peptides' stability in simulated gastric and intestinal fluids. ApoB‐derived peptides were found to be nontoxic when tested on human gastric carcinoma cells SNU‐1 and on human colon‐rectal adenocarcinoma cells HT‐29, and not to induce resistance phenotype in Salmonella strains. Bioinformatic analyses showed that the peptides are susceptible to several proteases, as also confirmed by experiments in simulated gastric and intestinal fluids. Altogether these findings open interesting perspectives to the future applicability of ApoB‐derived peptides as novel food biopreservatives.

Current allele distribution of the human longevity gene APOE in Europe can mainly be explained by ancient admixture.

Variation in apolipoprotein E (APOE) has been shown to have the strongest genetic effect on human longevity. The aim of this study was to unravel the evolutionary history of the three major APOE alleles in Europe by analysing ancient samples up to 12,000 years old. We detected significant allele frequency shifts between populations and over time. Our analyses indicated that selection led to large frequency differences between the earliest European populations (i.e., hunter-gatherers vs. first farmers), possibly due to changes in diet/lifestyle. In contrast, the allele distributions in populations from ~4000 BCE onward can mainly be explained by admixture, suggesting that it also played an important role in shaping current APOE variation. In any case, the resulting allele frequencies strongly influence the predisposition for longevity today, likely as a consequence of past adaptations and demographic processes.

APOE modulates microglial immunometabolism in response to age, amyloid pathology, and inflammatory challenge

The E4 allele of Apolipoprotein E (APOE) is associated with both metabolic dysfunction and a heightened pro-inflammatory response: two findings that may be intrinsically linked through the concept of immunometabolism. Here, we combined bulk, single-cell, and spatial transcriptomics with cell-specific and spatially resolved metabolic analyses in mice expressing human APOE to systematically address the role of APOE across age, neuroinflammation, and AD pathology. RNA sequencing (RNA-seq) highlighted immunometabolic changes across the APOE4 glial transcriptome, specifically in subsets of metabolically distinct microglia enriched in the E4 brain during aging or following an inflammatory challenge. E4 microglia display increased Hif1α expression and a disrupted tricarboxylic acid (TCA) cycle and are inherently pro-glycolytic, while spatial transcriptomics and mass spectrometry imaging highlight an E4-specific response to amyloid that is characterized by widespread alterations in lipid metabolism. Taken together, our findings emphasize a central role for APOE in regulating microglial immunometabolism and provide valuable, interactive resources for discovery and validation research.

Exposure to chlorpyrifos during pregnancy differentially affects social behavior and GABA signaling elements in an APOE- and sex-dependent manner in a transgenic mouse model

The massive use of chlorpyrifos (CPF) has been associated with an increased prevalence of neurodevelopmental disorders. Some previous studies have shown that prenatal, but not postnatal, CPF exposure causes social behavior deficits in mice depending on sex while others have found that in transgenic mice models carrying the human apolipoprotein E (APOE) ε3 and ε4 allele confer different vulnerabilities to either behavioral or metabolic disorders after CPF exposure. This study aims to evaluate, in both sexes, how prenatal CPF exposure and APOE genotype impact on social behavior and its relation to changes in GABAergic and glutamatergic systems. For this purpose, apoE3 and apoE4 transgenic mice were exposed through the diet to 0 or 1 mg/kg/day of CPF, between gestational day 12 and 18. A three-chamber test was used to assess social behavior on postnatal day (PND) 45. Then, mice were sacrificed, and hippocampal samples were analyzed to study the gene expression of GABAergic and glutamatergic elements. Results showed that prenatal exposure to CPF impaired social novelty preference and increased the expression of GABA-A α1 subunit in females of both genotypes. In addition, the expression of GAD1, the ionic cotransporter KCC2 and the GABA-A α2 and α5 subunits were increased in apoE3 mice, whereas CPF treatment only accentuated the expression of GAD1 and KCC2. Nevertheless, future research is needed to evaluate whether the influences detected in the GABAergic system are present and functionally relevant in adults and old mice.

Interactions of fentanyl with blood platelets and plasma proteins: platelet sensitivity to prasugrel metabolite is not affected by fentanyl under in vitro conditions

BackgroundClinical trials indicate that fentanyl, like morphine, may impair intestinal absorption and thus decrease the efficacy of oral P2Y12 inhibitors, such as clopidogrel, ticagrelor, and prasugrel. However, the ability of fentanyl to directly negate or reduce the inhibitory effect of P2Y12 receptor antagonists on platelet function has not been established. A series of in vitro experiments was performed to investigate the ability of fentanyl to activate platelets, potentiate platelet response to ADP, and/or diminish platelet sensitivity to prasugrel metabolite (R-138727) in agonist-stimulated platelets. The selectivity and specificity of fentanyl toward major carrier proteins has been also studied.MethodsBlood was obtained from healthy volunteers (19 women and 12 men; mean age 40 ± 13 years). Platelet function was measured in whole blood, platelet-rich plasma and in suspensions of isolated platelets by flow cytometry, impedance and optical aggregometry. Surface plasmon resonance and molecular docking were employed to determine the binding kinetics of fentanyl to human albumin, α1-acid glycoprotein, apolipoprotein A-1 and apolipoprotein B-100.ResultsWhen applied at therapeutic and supratherapeutic concentrations under various experimental conditions, fentanyl had no potential to stimulate platelet activation and aggregation, or potentiate platelet response to ADP, nor did it affect platelet susceptibility to prasugrel metabolite in ADP-stimulated platelets. In addition, fentanyl was found to interact with all the examined carrier proteins with dissociation constants in the order of 10–4 to 10–9 M.ConclusionsIt does not seem that the delayed platelet responsiveness to oral P2Y12 inhibitors, such as prasugrel, in patients undergoing percutaneous coronary intervention, results from direct interactions between fentanyl and blood platelets. Apolipoproteins, similarly to albumin and α1-acid glycoprotein, appear to be important carriers of fentanyl in blood.

Age and APOE affect L-carnitine system metabolites in the brain in the APOE-TR model.

With age the apolipoprotein E (APOE) E4 allele (involved in lipid homeostasis) is associated with perturbation of bioenergetics pathways in Alzheimer's disease (AD). We therefore hypothesized that in aging mice APOE genotype would affect the L-carnitine system (central to lipid bioenergetics), in the brain and in the periphery. Using liquid chromatography-mass spectrometry, levels of L-carnitine and associated metabolites: γ-butyrobetaine (GBB), crotonobetaine, as well as acylcarnitines, were evaluated at 10-, 25-, and 50-weeks, in the brain and the periphery, in a targeted replacement mouse model of human APOE (APOE-TR). Aged APOE-TR mice were also orally administered 125 mg/kg of L-carnitine daily for 7 days followed by evaluation of brain, liver, and plasma L-carnitine system metabolites. Compared to E4-TR, an age-dependent increase among E2- and E3-TR mice was detected for medium- and long-chain acylcarnitines (MCA and LCA, respectively) within the cerebrovasculature and brain parenchyma. While following L-carnitine oral challenge, E4-TR mice had higher increases in the L-carnitine metabolites, GBB and crotonobetaine in the brain and a reduction of plasma to brain total acylcarnitine ratios compared to other genotypes. These studies suggest that with aging, the presence of the E4 allele may contribute to alterations in the L-carnitine bioenergetic system and to the generation of L-carnitine metabolites that could have detrimental effects on the vascular system. Collectively the E4 allele and aging may therefore contribute to AD pathogenesis through aging-related lipid bioenergetics as well as cerebrovascular dysfunctions.

Brain apolipoprotein E levels in mice challenged by a Western diet increase in an allele-dependent manner

Human apolipoprotein E (APOE) is the greatest determinant of genetic risk for memory deficits and Alzheimer’s disease (AD). While APOE4 drives memory loss and high AD risk, APOE2 leads to healthy brain aging and reduced AD risk compared to the common APOE3 variant. We examined brain APOE protein levels in humanized mice homozygous for these alleles and found baseline levels to be age- and isoform-dependent: APOE2 levels were greater than APOE3, which were greater than APOE4. Despite the understanding that APOE lipoparticles do not traverse the blood–brain barrier, we show that brain APOE levels are responsive to dietary fat intake. Challenging mice for 6 months on a Western diet high in fat and cholesterol increased APOE protein levels in an allele-dependent fashion with a much greater increase within blood plasma than within the brain. In the brain, APOE2 levels responded most to the Western diet challenge, increasing by 20 % to 30 %. While increased lipoparticles are generally deleterious in the periphery, we propose that higher brain APOE2 levels may represent a readily available pool of beneficial lipid particles for neurons.

Apolipoprotein E isoform does not influence trans-synaptic spread of tau pathology in a mouse model.

A key hallmark of Alzheimer's disease (AD) is the accumulation of hyperphosphorylated tau in neurofibrillary tangles. This occurs alongside neuroinflammation and neurodegeneration. Pathological tau propagates through the AD brain in a defined manner, which correlates with neuron and synapse loss and cognitive decline. One proposed mechanism of tau spread is through synaptically connected brain structures. Apolipoprotein E4 (APOE4) genotype is the strongest genetic risk factor for late-onset AD and is associated with increased tau burden. Whether the apolipoprotein E (APOE) genotype influences neurodegeneration via tau spread is currently unknown. Here, we demonstrate that virally expressed human tau (with the P301L mutation) injected into mouse entorhinal cortex at 5-6 months or 15-16 months of age spreads trans-synaptically to the hippocampus by 14 weeks post-injection. Injections of tau in mice expressing human APOE2, APOE3 or APOE4, as well as APOE knock-outs, showed that tau can spread trans-synaptically in all genotypes and that APOE genotype and age do not affect the spread of tau. These data suggest that APOE genotype is not directly linked to synaptic spread of tau in our model, but other mechanisms involving non-cell autonomous manners of tau spread are still possible.

Abstract 1999: Structural and Functional Analysis of Cavia porcellus and Human Apolipoprotein E4 to Understand its Role in Amyloidogenesis

Abstract 1999: Structural and Functional Analysis of Cavia porcellus and Human Apolipoprotein E4 to Understand its Role in Amyloidogenesis

A method for detection of anti-drug antibodies to a biotherapeutic (CSL112) with endogenous counterpart (apolipoprotein A-I) using a novel sample pre-treatment electrochemiluminescence assay

BackgroundThere are numerous challenges encountered during clinical testing for an immunogenic response to a plasma-derived therapeutic. Distinguishing between antibodies that recognize endogenous versus therapeutic protein can be particularly difficult. This study focused on CSL112 (human plasma-derived apolipoprotein A-I; apoA-I), which is in clinical development for reducing the risk of recurrent major adverse cardiovascular events following acute myocardial infarction. AimTo develop and validate a high-throughput, highly sensitive and specific assay to detect antibodies to CSL112 that can be used for immunogenicity assessment in large clinical studies. ResultsWe developed a clinical anti-drug antibody (ADA) assay utilizing an immunoglobulin purification step that improved specificity and drug tolerance, demonstrating that measurement of pre-existing or treatment emergent ADAs was highly dependent on assay format. The Sample Pre-treatment Electrochemiluminescence (ECL; SPECL) assay incorporates a protein A extraction of serum samples before a bridging assay is performed on an ECL platform. The assay is qualitative, sensitive (lower limit of quantification <39 ng/mL) and has a drug tolerance of 0.5 mg/mL in line with U.S. Food and Drug Administration requirements for clinical immunogenicity assays for therapeutic proteins. Importantly, the SPECL assay demonstrated the absence of antibodies to both apoA-I and CSL112 both prior to drug exposure and after repeated dosing across multiple trials (n = 970 subjects). ConclusionThe SPECL method has been validated and applied to support the CSL112 preclinical and clinical development program and has broader application to similar protein therapeutics. Attributes of the methodology include high drug tolerance, high sensitivity, selectivity, and precision. This format is amenable to automation providing the high throughput and reduced variability required to support large scale clinical studies that span extended time periods.

Engineered APOBEC3C Sequencing Enables Bisulfite-Free and Direct Detection of DNA Methylation at a Single-Base Resolution.

DNA methylation (5-methylcytosine, 5mC) is the most important epigenetic modification in mammals. Deciphering the roles of 5mC relies on the quantitative detection of 5mC at the single-base resolution. Bisulfite sequencing (BS-seq) is the most often employed technique for mapping 5mC in DNA. However, bisulfite treatment may cause serious degradation of input DNA due to the harsh reaction conditions. Here, we engineered the human apolipoprotein B mRNA-editing catalytic polypeptide-like 3C (A3C) protein to endow the engineered A3C (eA3C) protein with differential deamination activity toward cytosine and 5mC. By the virtue of the unique property of eA3C, we proposed an engineered A3C sequencing (EAC-seq) method for the bisulfite-free and quantitative mapping of 5mC in DNA at the single-base resolution. In EAC-seq, the eA3C protein can deaminate C but not 5mC, which is employed to differentiate C and 5mC in sequencing. Using the EAC-seq method, we quantitatively detected 5mC in genomic DNA of lung cancer tissue. In contrast to the harsh reaction conditions of BS-seq, which could lead to significant degradation of DNA, the whole procedure of EAC-seq is carried out under mild conditions, thereby preventing DNA damage. Taken together, the EAC-seq approach is bisulfite-free and straightforward, making it an invaluable tool for the quantitative detection of 5mC in limited DNA at the single-base resolution.

APOE genotype modifies microglial immunometabolism

AbstractBackgroundMetabolic dysfunction and neuroinflammation characterize Alzheimer’s disease (AD), but it is unclear if these two facets of the disease are linked. The E4 allele of Apolipoprotein E (APOE) is the strongest genetic risk factor for late‐onset AD and is associated with increased neuroinflammation. Recent data from our lab and others show that E4 is also associated with increased aerobic glycolysis. These two findings may be intrinsically linked through the concept of ‘immunometabolism’ ‐ an emerging paradigm that implicates increased glycolysis as a core requirement during pro‐inflammatory activation, whereas increased oxidative phosphorylation is required for anti‐inflammatory responses.MethodPrimary microglia were isolated from targeted replacement mice expressing human APOE isoforms and stimulated with pro‐inflammatory (lipopolysaccharide (LPS); IFNγ + TNFα) or anti‐inflammatory (IL‐10; IL‐4 + IL‐13) cytokines. Metabolic responses were measured using the Agilent Seahorse platform and targeted metabolomics. We also performed single‐cell RNA sequencing on brains from APOE targeted replacement mice at 3‐, 10‐, and 18 months of age +/‐ LPS.ResultSeahorse revealed increased glycolysis and decreased mitochondrial respiration in E4 microglia. Targeted metabolomics revealed increased lactate and succinate in E4 microglia, metabolites known to accumulate in pro‐inflammatory macrophages. Aged E4 brains were uniquely found to harbor a metabolically distinct subcluster of microglia that expressed a signature similar to the established ‘disease associated microglia’ phenotype, even in the absence of neuropathology. SCENIC regulon analysis linked this cluster to the transcription network of HIF1a, and increased expression of HIF1a was validated in E4 microglia. In LPS‐treated animals, two distinct microglia subclusters emerged in E4 brains that were defined by altered expression of genes relating to oxidative phosphorylation and mitochondrial function.ConclusionOur findings reveal that age and LPS treatment induce a distinct metabolic response in E4 microglia. The accumulation of lactate and succinate and increased glycolysis in E4 microglia indicate altered metabolic preference conducive to pro‐inflammatory activation, whereas the decreased mitochondrial respiration may preclude effective anti‐inflammatory responses. We propose that this altered metabolism skews E4 microglia towards a phenotype that favors chronic neuroinflammation and neurodegeneration. Thus, reprogramming metabolism in E4 microglia may provide a novel therapeutic avenue for the treatment of AD.

The Influence of Preforming Protein Coronas on the Performance of Dengue NS1 Immunoassays.

The effect of preformed protein coronas on immunoassays for Dengue nonstructural protein 1 (NS1) immunoassays was investigated. The composition of the protein corona that forms around nanoparticle-antibody conjugates in human serum was characterized, and selected proteins from the corona were used for preformed coronas (human serum albumin and apolipoprotein A1). Coronas were formed and characterized by dynamic light scattering (DLS), and the nanoparticle-conjugate was probed by optical absorption spectroscopy. Immunoassays were run, and performance was quantified by analyzing the strip intensity as a function of NS1 concentration. The preformed coronas influenced the limit of detection (LOD) of the assay and the affinity for the NS1 target (KD). The resulting KD and LODs for the NP-Ab-ApoA1 immunoprobes were 0.83 nM and 1.24 nM, respectively. For the NP-Ab -HSA coronas, the test line intensity was lower by 33% at a given NS1 concentration than for the NP-Ab immunoprobes, and KD was 0.14 nM, a slightly higher affinity. Due to the relatively large error of the negative control, a meaningful LOD for the NP-Ab with HSA coronas could not be determined.

Investigating the plasma-liver-brain axis of omega-3 fatty acid metabolism in mouse knock-in for the human apolipoprotein E epsilon 4 allele

The metabolism of docosahexaenoic acid (DHA), an omega-3 fatty acid, is different in carriers of APOE4, the main genetic risk factor for late-onset Alzheimer's disease. The brain relies on the plasma DHA pool for its need, but the plasma-liver-brain axis in relation to cognition remains obscure. We hypothesized that this relationship is compromised in APOE4 mice considering the differences in fatty acid metabolism between APOE3 and APOE4 mice. Male and female APOE3 and APOE4 mice were fed either a diet enriched with DHA (0.7 g DHA/100 g diet) or a control diet for 8 months. There was a significant genotype × diet interaction for DHA concentration in the liver and adipose tissue. In the cortex, a genotype effect was found where APOE4 mice had a higher concentration of DHA than APOE3 mice fed the control diet. There was a significant genotype × diet interaction for the liver and hippocampal arachidonic acid (AA). APOE4 mice had 20–30% lower plasma DHA and AA concentrations than APOE3 mice, independent of diet. Plasma and liver DHA levels were significantly correlated in APOE3 and APOE4 mice. In APOE4 mice, there was a significant correlation between plasma, adipose tissues, cortex DHA and the Barnes maze and/or with a better recognition index. Moreover, higher AA levels in the liver and the hippocampus of APOE4 mice were correlated with lower cognitive performance. Our results suggest that there is a plasma-liver-brain axis of DHA that is modified in APOE4 mice. Moreover, our data support that APOE4 mice rely more on plasma DHA than APOE3 mice, especially in cognitive performance. Any disturbance in plasma DHA metabolism might have a greater impact on cognition in APOE4 carriers.

A transgenic mouse model mimicking human cardiac amyloidosis

Abstract Background Heart failure (HF) pathophysiology complicating cardiac amyloidosis (CA) is poorly explored due to the lack of relevant animal model. A recently transgenic mouse expressing an amyloidogenic variant of human apolipoprotein AII was developed that showed ubiquitous amyloid deposit but limited data on cardiac involvement. Purpose To investigate heart structure and function in transgenic mice expressing an amyloidogenic variant of human apolipoprotein AII Methods Seventy-nine mice ageing 2 to 3 months were included in this study as follow: amyloidosis group (n=44) and sham (i.e. genetic mutation without phenotypic expression, n=35). Both were serially imaged by echocardiography (Vevo3100 Fujifilm) and cardiac magnetic resonance imaging (CMR, Biospec 4.7 tesla), and invasively explored by left–sided catheterization (pressure-volume loop [PV loop], Millar Catheterization), before sacrifice and histological investigations. Results As soon as 2–3 months of age, the amyloidosis group demonstrated significant left ventricular (LV) hypertrophy, diastolic dysfunction and left atrial dilatation compared with sham group (p&amp;lt;0.01). Left ventricular ejection fraction was initially normal in both groups but deteriorated in amyloidosis mice (p&amp;lt;0.001) before right ventricular function collapses (p&amp;lt;0.001). In amyloidosis group, PV loops showed significant LV end-diastolic pressure increase (p&amp;lt;0.001), stiffer LV (p&amp;lt;0.01) and reduced systolic function LV elastance (p&amp;lt;0.05). Invasive and non-invasive abnormalities paralleled severe CA deposits and subendocardial fibrosis matrix remodeling, both labeling by Congo red and Red Sirius coloration (p&amp;lt;0.001). CMR analysis showed significant T1 (p&amp;lt;0.05) and T2 (p&amp;lt;0.01) signal increase and significant decrease in myocardial perfusion (p&amp;lt;0.01) in the amyloidosis group. Clinically, mice with amyloidosis covered less distance during exercise test (p&amp;lt;0.001) and died earlier (log-rank test, p&amp;lt;0.01). Conclusion By mimicking human cardiac amyloidosis, the model of transgenic mouse expressing an amyloidogenic variant of human apolipoprotein AII is promising to investigate the underlying pathophysiology of heart failure due to amyloidosis. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Pfizer grant

Apolipoprotein E4 impairs the response of neurodegenerative retinal microglia and prevents neuronal loss in glaucoma

The apolipoprotein E4 (APOE4) allele is associated with an increased risk of Alzheimer disease and a decreased risk of glaucoma, but the underlying mechanisms remain poorly understood. Here, we found that in two mouse glaucoma models, microglia transitioned to a neurodegenerative phenotype characterized by upregulation of Apoe and Lgals3 (Galectin-3), which were also upregulated in human glaucomatous retinas. Mice with targeted deletion of Apoe in microglia or carrying the human APOE4 allele were protected from retinal ganglion cell (RGC) loss, despite elevated intraocular pressure (IOP). Similarly to Apoe-/- retinal microglia, APOE4-expressing microglia did not upregulate neurodegeneration-associated genes, including Lgals3, following IOP elevation. Genetic and pharmacologic targeting of Galectin-3 ameliorated RGC degeneration, and Galectin-3 expression was attenuated in human APOE4 glaucoma samples. These results demonstrate that impaired activation of APOE4 microglia is protective in glaucoma and that the APOE-Galectin-3 signaling can be targeted to treat this blinding disease.

Identification of molecules that correct structural and functional defects of naturally-occurring pathogenic apoA-I mutants

Background and Aims : Naturally-occurring mutations in human apolipoprotein A-I (apoA-I) have been shown to disturb protein conformation and induce functional defects that impair the levels and atheroprotective properties of HDL. One such apoA-I mutation, L178P, induces major defects in the structural integrity and functions of the protein that may underlie the reduced HDL-cholesterol and increased cardiovascular risk observed in carriers of the mutation. Here, a library of marketed drugs (∼1000 compounds) was screened against apoA-I[L178P] to identify molecules that can prevent mutant apoA-I from adopting its pathological conformation.