apoE Expression Research Articles

Age‐Related Enhanced BMP Signaling Elicits APOE‐Isoform Dependent Effects in IPSC Model of Alzheimer’s Disease

AbstractBackgroundAging is the strongest risk factor for developing Alzheimer’s Disease (AD), and APOE is the largest genetic risk factor for developing AD. Bone morphogenic protein 4 (BMP4) expression and subsequent signaling increases 10‐fold with age and is increased in AD patients compared to age‐matched controls. Enhanced BMP signaling in aged and AD brains suggest a potential molecular cascade involved in AD pathogenesis. A potential interaction exists between increased BMP signaling across lifespan APOE expression that contribute to risk of AD.MethodAD patient derived iPSC’s (APOE3/E4 genotype) and isogenic controls (APOE3/E3 genotype) were differentiated into astrocytes and neurons. Cells were grown for 35 days before treatment with BMP4 or vehicle for 3 days prior to fixation, protein/media collection, or preparation for single cell RNA sequencing (scRNAseq). For coculture studies, neurons and astrocytes of the same patient background were differentiated separately prior to combined plating and BMP treatment. Cocultures were in matched (APOE3/E4 neurons with APOE3/E4 astrocytes) or mismatched (APOE3/E3 neurons with APOE3/E4 astrocytes) conditions to understand the non‐cell autonomous effects of APOE genotype.ResultUpon BMP treatment, APOE3/E4 compared to APOE3/E3 astrocytes exhibit accumulation of lipid droplets with changes in lipid composition. Increased free cholesterol levels as well as triglyceride accumulation is observed in APOE3/E4 astrocytes and is further exacerbated with BMP treatment. RNA‐sequencing analysis reveals marked decreased expression in genes related to oxidative phosphorylation and increased cholesterol synthesis and metabolism in APOE3/E4 astrocytes that is modulated by BMP treatment. In a non‐cell autonomous fashion, APOE3/E3 neurons, when paired with APOE3/E4 astrocytes, express exacerbated pTau levels and aberrant metabolic processes in a BMP‐dependent manner.ConclusionOur results indicate an interaction between genetic and aging factors in cellular processes relevant to AD. Enhanced BMP signaling confers aberrant lipid composition and metabolic processing in APOE3/E4 astrocytes when compared to APOE3/E3. Subsequent BMP‐dependent non‐cell autonomous effects in APOE3/E3 neurons are observed when cocultured with APOE3/E4 astrocytes. This data suggests age‐associated increase in BMP signaling may modulate APOE isoform‐dependent metabolic processes and increase risk for APOE‐mediated pathological cascades.

Neural responses to peripheral infection in Alzheimer’s disease model mice

AbstractBackgroundClinical and animal studies have suggested that peripheral inflammation affects the central nervous system (CNS) and may be a major factor in the pathophysiology of neurodegenerative diseases like AD. Furthermore, a variety of signaling factors originating in the periphery, such as inflammatory mediators, have been associated with the regulation of brain barrier functions. Here, we hypothesized that the presence of peripheral inflammation dysregulates brain barriers’ integrity and induces neuroinflammation with consequences on amyloid pathology.MethodIn this study, we employed an AD mouse model nasally infected with Staphylococcus aureus to assess the impact of chronic or acute peripheral inflammation on brain transcriptome and amyloid pathology. We utilized both single cell and Spatial Transcriptomics to better determine transcriptional response to peripheral inflammation.ResultThe chronic exposure increased the diffuse and compact amyloid plaques and blood cytokine levels. Following a short‐term exposure, single‐cell and spatial transcriptomics uncovered cell type‐ and spatial‐specific transcriptional changes indicating a dysregulation of the brain barriers, including the blood‐brain and the blood‐cerebrospinal fluid barriers. Brain macrophages exhibited increased Apoe expression and macrophage‐specific genes were upregulated at ventricular areas of infected mice. In addition, we report an increase of disease associated microglia genes around the Ab plaques, together with disbalances in neuronal expression in response to peripheral inflammation.ConclusionWe observed that low‐grade peripheral infection triggers transcriptional responses linked to brain barriers and brain infiltrated/resident macrophages indicate a fundamental importance of them in the mechanisms linking peripheral inflammation and AD pathogenesis. Finally, we showed that bacterial infection caused molecular changes restricted to specific cell types and/or brain spatial microenvironments, which highlights the relevance of studying brain molecular responses with high resolution in order to have new insights on AD etiology.

Influence of colour background on anti-viral activity against viral haemorrhagic septicaemia virus in zebrafish regulated by circadian rhythm signalling pathway.

The influence of colour background on the regulation of behavioural and physiological responses in zebrafish is widely recognized. However, its specific effect on virus infection in zebrafish remains unclear. This study aimed to explore the susceptibility of zebrafish to viral haemorrhagic septicaemia virus (VHSV) infection in relation to background colour, investigate the underlying mechanisms, and elucidate the involvement of key molecules, using proteomic and gene expression analyses. The results revealed that zebrafish housed in a blue tank exhibited higher survival rates and considerably reduced VHSV replication compared to those housed in a yellow tank. Further, up-regulation of apolipoprotein 1 (APOA1) was identified as a crucial shared mechanism associated with survival in zebrafish exposed to VHSV infection and reared in a blue background. The mRNA expression level of bmal1a, a core gene involved in the circadian rhythm, was consistently downregulated in fish from the blue tank compared to fish from the yellow tank, regardless of infection status. Subsequently, zebrafish in the blue tank were exposed to daylight conditions to stimulate per2 and pgc1a expression, aiming to investigate their potential impact on VHSV infection. The validity of these interconnected events, triggered by background colour, involving APOA1 up-regulation, circadian rhythm modulation, and antiviral responses, was confirmed by treatments with hesperetin and cyclosporine A, an activator and inhibitor of apoa1 respectively. Our findings revealed the influence of background colour on the apoa1 expression level, thus establishing the involvement of a novel network through circadian rhythm signalling.

Intestinal Epithelial-Derived IL-34 Regulates Macrophage Polarization in an Apolipoprotein E Dependent Manner and Mitigates the Severity of Graft Versus Host Disease

Acute graft versus host disease (GVHD) of the gastrointestinal (GI) tract is a major complication of allogeneic bone marrow transplantation. While donor T cells are the proximate trigger of GVHD, innate cells also contribute to disease pathogenesis, although the role of these cell populations is not as well defined. Macrophages, for example, are known contributors in the pathophysiology of chronic GVHD, but their role in acute GVHD is not well delineated. Fundamentally, macrophages are dependent upon exposure to m-CSF and IL-34 which serve as critical trophic factors necessary for their development through binding to the CSF-1R. IL-34 is a more recently discovered cytokine produced by macrophages, but whose role in GVHD pathogenesis is unknown. To examine this question, we employed a murine bone marrow transplantation model (B10.BR [H-2k]®B6[H-2b]) and observed that that there was no difference in GVHD-induced lethality when recipients were reconstituted with marrow grafts from wild type (WT) or IL-34 -/- donors. In contrast, recipient IL-34 -/- animals had significantly worse survival compared to WT mice indicating that host IL-34 expression protected animals from lethal GVHD. We observed no difference in the absolute number of donor macrophages in the colons of WT versus IL-34 -/- mice; however, IL-34 -/- recipient mice had a significant increase in the number of inflammatory Ly6C + macrophages, and a corresponding decrease in Ly6C - cells. Single cell RNA sequence (scRNAseq) analysis of donor macrophages from the colons of WT and IL-34 -/- recipients revealed that macrophages from WT animals had increased expression of anti-inflammatory genes (i.e., CD83, ApoE, Selenop, Lyz1 and Mrc1), whereas macrophages from IL-34 -/- recipients had increased expression of pro-inflammatory genes (i.e., Ifitm1, S100A8, S100A9 and GOs2), indicating that absence of host IL-34 skewed donor macrophages towards an inflammatory phenotype. Since the CSF-1R is not expressed on T cells, we sought to determine the effect of IL-34/CSF-1R signaling on proinflammatory T cells in GVHD target organs. scRNAseq analysis of colonic CD4+ T cells revealed that Csf2 (GM-CSF) was the most differentially expressed gene in IL-34 -/- CD4+ T cells. Functionally, this was confirmed by the observation of a significantly increased number of CD4 + GM-CSF+ T cells in the colons of these mice. Notably, there was no difference in proinflammatory CD8 + T cells, nor any effect on T cell phenotype in the liver or lung, demonstrating that the mitigating effect of host IL-34 expression was confined to the GI tract. To determine the cellular source of IL-34 production, we employed IL-34 LacZ reporter mice and showed that β-Gal co-localized with the epithelial marker, E-cadherin, indicating IL-34 is produced primarily by intestinal epithelial cells. Additional studies using chimeric mice in which IL-34 was restricted to either the hematopoietic or non-hematopoietic compartmentrevealed that absence of IL-34 in the non-hematopoietic compartment phenocopied findings observed with global IL-34 -/- animals, confirming that intestinal epithelial cells were the primary source of this cytokine. The administration of exogenous IL-34 prolonged survival, abrogated pathological damage in the colon and resulted in a corresponding decrease in pro-inflammatory macrophages and T cells, demonstrating this pathway could be pharmacologically targeted. Re-analysis of the scRNAseq data on donor macrophages from the colons of WT and IL-34 -/- mice revealed that apolipoprotein E ( Apoe) was the most differentially expressed gene in macrophages from WT GVHD animals. To confirm a functional role for ApoE, mice were transplanted with T cell depleted (TCD) BM from either WT or ApoE -/- mice and treated with IL-34. These studies revealed that the protective effect conferred by IL-34 was abrogated in animals that received TCD ApoE -/- BM grafts, indicating that ApoE expression in donor macrophages was necessary for agonist driven IL-34-mediated regulation of GVHD. Finally, we confirmed these studies have translational relevance by demonstrating IL-34 and Apoe have increased expression in intestinal epithelial cells and macrophages, respectively, in the colons of humans with GVHD. Thus, these results identify IL-34 as a novel intestinal epithelial cell-derived cytokine that regulates macrophage polarization and mitigates GVHD in an ApoE-dependent manner.

Loss of Lipid Carrier ApoE Exacerbates Brain Glial and Inflammatory Responses after Lysosomal GBA1 Inhibition.

Tightly regulated and highly adaptive lipid metabolic and transport pathways are critical to maintaining brain cellular lipid homeostasis and responding to lipid and inflammatory stress to preserve brain function and health. Deficits in the lipid handling genes APOE and GBA1 are the most significant genetic risk factors for Lewy body dementia and related dementia syndromes. Parkinson's disease patients who carry both APOE4 and GBA1 variants have accelerated cognitive decline compared to single variant carriers. To investigate functional interactions between brain ApoE and GBA1, in vivo GBA1 inhibition was tested in WT versus ApoE-deficient mice. The experiments demonstrated glycolipid stress caused by GBA1 inhibition in WT mice induced ApoE expression in several brain regions associated with movement and dementia disorders. The absence of ApoE in ApoE-KO mice amplified complement C1q elevations, reactive microgliosis and astrocytosis after glycolipid stress. Mechanistically, GBA1 inhibition triggered increases in cell surface and intracellular lipid transporters ABCA1 and NPC1, respectively. Interestingly, the absence of NPC1 in mice also triggered elevations of brain ApoE levels. These new data show that brain ApoE, GBA1 and NPC1 functions are interconnected in vivo, and that the removal or reduction of ApoE would likely be detrimental to brain function. These results provide important insights into brain ApoE adaptive responses to increased lipid loads.

Cholesterol Metabolism in Pancreatic Cancer.

Pancreatic cancer's substantial impact on cancer-related mortality, responsible for 8% of cancer deaths and ranking fourth in the US, persists despite advancements, with a five-year relative survival rate of only 11%. Forecasts predict a 70% surge in new cases and a 72% increase in global pancreatic cancer-related deaths by 2040. This review explores the intrinsic metabolic reprogramming of pancreatic cancer, focusing on the mevalonate pathway, including cholesterol biosynthesis, transportation, targeting strategies, and clinical studies. The mevalonate pathway, central to cellular metabolism, significantly shapes pancreatic cancer progression. Acetyl coenzyme A (Acetyl-CoA) serves a dual role in fatty acid and cholesterol biosynthesis, fueling acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) development. Enzymes, including acetoacetyl-CoA thiolase, 3-hydroxy-3methylglutaryl-CoA (HMG-CoA) synthase, and HMG-CoA reductase, are key enzymes in pancreatic cancer. Inhibiting HMG-CoA reductase, e.g., by using statins, shows promise in delaying PanIN progression and impeding pancreatic cancer. Dysregulation of cholesterol modification, uptake, and transport significantly impacts tumor progression, with Sterol O-acyltransferase 1 (SOAT1) driving cholesterol ester (CE) accumulation and disrupted low-density lipoprotein receptor (LDLR) expression contributing to cancer recurrence. Apolipoprotein E (ApoE) expression in tumor stroma influences immune suppression. Clinical trials targeting cholesterol metabolism, including statins and SOAT1 inhibitors, exhibit potential anti-tumor effects, and combination therapies enhance efficacy. This review provides insights into cholesterol metabolism's convergence with pancreatic cancer, shedding light on therapeutic avenues and ongoing clinical investigations.

Cell-autonomous effects of APOE4 in restricting microglial response in brain homeostasis and Alzheimer's disease.

Microglial involvement in Alzheimer's disease (AD) pathology has emerged as a risk-determining pathogenic event. While apolipoprotein E (APOE) is known to modify AD risk, it remains unclear how microglial apoE impacts brain cognition and AD pathology. Here, using conditional mouse models expressing apoE isoforms in microglia and central nervous system-associated macrophages (CAMs), we demonstrate a cell-autonomous effect of apoE3-mediated microglial activation and function, which are negated by apoE4. Expression of apoE3 in microglia/CAMs improves cognitive function, increases microglia surrounding amyloid plaque and reduces amyloid pathology and associated toxicity, whereas apoE4 expression either compromises or has no effects on these outcomes by impairing lipid metabolism. Single-cell transcriptomic profiling reveals increased antigen presentation and interferon pathways upon apoE3 expression. In contrast, apoE4 expression downregulates complement and lysosomal pathways, and promotes stress-related responses. Moreover, in the presence of mouse endogenous apoE, microglial apoE4 exacerbates amyloid pathology. Finally, we observed a reduction in Lgals3-positive responsive microglia surrounding amyloid plaque and an increased accumulation of lipid droplets in APOE4 human brains and induced pluripotent stem cell-derived microglia. Our findings establish critical isoform-dependent effects of microglia/CAM-expressed apoE in brain function and the development of amyloid pathology, providing new insight into how apoE4 vastly increases AD risk.

Avocado Paste Phenolics Mitigate a High-Fat Diet-Induced Plasma HDL Decrease in Male Wistar Rats, by Altering the mRNA Expression of Hepatic SCARB1.

Avocado paste (AP) is the main industrial byproduct of its processing, and retains various phenolic compounds (PCs). PCs are known to normalize the plasma lipid profile, but those from avocado byproducts have been minimally studied. We report the normalizing effects of an AP-derived phenolic extract (PE) on the plasma lipid profile of male Wistar rats. A standard (SD) and high-fat diet (HFD) were formulated, and the same diets were supplemented with 1 g/kg of diet of PE (SD + PE and HFD + PE). Rats were fed these diets during an 8-week period. The HFD induced signs of dyslipidemia, but PE treatment countered the decrease in HDL. Relative mRNA expression (real-time PCR) of the hepatic HDL receptor (SCARB1) increased in both groups (SD + PE and HFD + PE), while the LDR receptor (LDLR) increased in SD + PE group. The mRNA expression of apolipoproteins APOA1 and APOB was unaffected. We conclude that PCs from AP can counter a diet-induced decrease in plasma HDL by acting on the mRNA expression of its hepatic receptor.

ApoE enhances mitochondrial metabolism via microRNA-142a/146a-regulated circuits that suppress hematopoiesis and inflammation in hyperlipidemia

Apolipoprotein E (ApoE) is recognized for its pleiotropic properties that suppress inflammation. We report that ApoE serves as a metabolic rheostat that regulates microRNA control of glycolytic and mitochondrial activity in myeloid cells and hematopoietic stem and progenitor cells (HSPCs). ApoE expression in myeloid cells increases microRNA-146a, which reduces nuclear factor κB (NF-κB)-driven GLUT1 expression and glycolytic activity. In contrast, ApoE expression reduces microRNA-142a, which increases carnitine palmitoyltransferase 1a (CPT1A) expression, fatty acid oxidation, and oxidative phosphorylation. Improved mitochondrial metabolism by ApoE expression causes an enrichment of tricarboxylic acid (TCA) cycle metabolites and nicotinamide adenine dinucleotide (NAD+) in macrophages. The study of mice with conditional ApoE expression supports the capacity of ApoE to foster microRNA-controlled immunometabolism. Modulation of microRNA-146a and -142a in the hematopoietic system of hyperlipidemic mice using RNA mimics and antagonists, respectively, improves mitochondrial metabolism, which suppresses inflammation and hematopoiesis. Our findings unveil microRNA regulatory circuits, controlled by ApoE, that exert metabolic control over hematopoiesis and inflammation in hyperlipidemia.

Large-scale whole exome sequencing studies identify two genes,CTSL and APOE, associated with lung cancer.

Common genetic variants associated with lung cancer have been well studied in the past decade. However, only 12.3% heritability has been explained by these variants. In this study, we investigate the contribution of rare variants (RVs) (minor allele frequency <0.01) to lung cancer through two large whole exome sequencing case-control studies. We first performed gene-based association tests using a novel Bayes Factor statistic in the International Lung Cancer Consortium, the discovery study (European, 1042 cases vs. 881 controls). The top genes identified are further assessed in the UK Biobank (European, 630 cases vs. 172 864 controls), the replication study. After controlling for the false discovery rate, we found two genes, CTSL and APOE, significantly associated with lung cancer in both studies. Single variant tests in UK Biobank identified 4 RVs (3 missense variants) in CTSL and 2 RVs (1 missense variant) in APOE stongly associated with lung cancer (OR between 2.0 and 139.0). The role of these genetic variants in the regulation of CTSL or APOE expression remains unclear. If such a role is established, this could have important therapeutic implications for lung cancer patients.

Neuronal Stem Cells from Late-Onset Alzheimer Patients Show Altered Regulation of Sirtuin 1 Depending on Apolipoprotein E Indicating Disturbed Stem Cell Plasticity.

Late-onset Alzheimer's disease (AD) is a complex multifactorial disease. The greatest known risk factor for late-onset AD is the E4 allele of the apolipoprotein E (APOE), while increasing age is the greatest known non-genetic risk factor. The cell type-specific functions of neural stem cells (NSCs), in particular their stem cell plasticity, remain poorly explored in the context of AD pathology. Here, we describe a new model that employs late-onset AD patient-derived induced pluripotent stem cells (iPSCs) to generate NSCs and to examine the role played by APOE4 in the expression of aging markers such as sirtuin 1 (SIRT1) in comparison to healthy subjects carrying APOE3. The effect of aging was investigated by using iPSC-derived NSCs from old age subjects as healthy matched controls. Transcript and protein analysis revealed that genes were expressed differently in NSCs from late-onset AD patients, e.g., exhibiting reduced autophagy-related protein 7 (ATG7), phosphatase and tensin homolog (PTEN), and fibroblast growth factor 2 (FGF2). Since SIRT1 expression differed between APOE3 and APOE4 NSCs, the suppression of APOE function in NSCs also repressed the expression of SIRT1. However, the forced expression of APOE3 by plasmids did not recover differently expressed genes. The altered aging markers indicate decreased plasticity of NSCs. Our study provides a suitable in vitro model to investigate changes in human NSCs associated with aging, APOE4, and late-onset AD.

A Distinct Microglial Cell Population Expressing Both CD86 and CD206 Constitutes a Dominant Type and Executes Phagocytosis in Two Mouse Models of Retinal Degeneration.

Microglial cells are the key regulators of inflammation during retinal degeneration (RD) and are conventionally classified as M1 or M2. However, whether the M1/M2 classification exactly reflects the functional classification of microglial cells in the retina remains debatable. We examined the spatiotemporal changes of microglial cells in the blue-LED and NaIO3-induced RD mice models using M1/M2 markers and functional genes. TUNEL assay was performed to detect photoreceptor cell death, and microglial cells were labeled with anti-IBA1, P2RY12, CD86, and CD206 antibodies. FACS was used to isolate microglial cells with anti-CD206 and CD86 antibodies, and qRT-PCR was performed to evaluate Il-10, Il-6, Trem-2, Apoe, and Lyz2 expression. TUNEL-positive cells were detected in the outer nuclear layer (ONL) from 24 h to 72 h post-RD induction. At 24 h, P2RY12 was decreased and CD86 was increased, and CD86/CD206 double-labeled cells occupied the dominant population at 72 h. And CD86/CD206 double-labeled cells showed a significant increase in Apoe, Trem2, and Lyz2 levels but not in those of Il-6 and Il-10. Our results demonstrate that microglial cells in active RD cannot be classified as M1 or M2, and the majority of microglia express both CD86 and CD206, which are involved in phagocytosis rather than inflammation.

Salvia miltiorrhiza and Tanshinone IIA reduce endothelial inflammation and atherosclerotic plaque formation through inhibiting COX-2

The mechanisms of Salvia miltiorrhiza (SM) and Tanshinone IIA (Tan IIA) in the treatment of atherosclerosis was examined by combining network pharmacology and molecular biology experiments. The TCMSP and BATMAN-TCM databases provided 104 SM candidate ingredients and 813 target genes, while GEO and GeneCards databases identified 35 overlapping targets between SM and coronary artery disease (CAD). From these data, we constructed a CAD-target-active ingredient network, and using Gene Ontology (GO) and KEGG pathway analysis, 211 GO terms and 43 pathways were identified, which facilitated the construction of a key active ingredient-target-pathway network. We then constructed a protein-protein interaction (PPI) network and performed molecular docking simulations between Tan IIA and 10 key target proteins to analyze the interactions between the molecule and the protein. SM was found to alleviate CAD by reducing the expression of key pro-inflammatory factors, such as COX-2 (PTGS2), MMP9, ICAM1, TNF-α, and NF-κB. Tan IIA was identified as the primary effective component of SM in treating CAD, with TNF and PTGS2 being its main targets. We further validated these findings using in vitro/in vivo experiments. The results showed that both SM and Tan IIA attenuated the buildup of plaque and the accumulation of lipids in ApoE-/- mice. In addition, SM and Tan IIA reduced vascular inflammatory factors expression in ApoE-/- mice and ox-LDL-cultured HUVECs. Furthermore, our findings showed that Tan IIA reduced vascular endothelial inflammation and prevented plaque formation via COX-2/TNF-a/NF-κB signaling pathway. We have demonstrated for the first time that Tan IIA plays a vital role in attenuating atherosclerosis by downregulating COX-2 expression.

ApoE4 expression disrupts tau uptake, trafficking, and clearance in astrocytes.

Tauopathies are a collection of neurodegenerative diseases characterized by the accumulation of pathogenic aggregates of the microtubule-associated protein tau. Despite the prevalence and diversity of tau astrogliopathy in tauopathies, the interactions between astrocytes and tau in the brain, and the influence of neurodegenerative genetic risk factors like the apolipoprotein E4 (apoE4) isoform, are largely unknown. Here, we leveraged primary and immortalized astrocytes expressing humanized apoE isoforms to characterize the mechanisms by which astrocytes interact with and eliminate extracellular tau, and the influence of apoE genotype on these processes. Our work indicates that astrocytes rapidly internalize, process, and release tau via an exosomal secretory mechanism under physiological conditions. However, we found that apoE4 disrupted these processes in comparison to apoE3, resulting in an astrocytic phenotype prone to intracellular tau accumulation. Furthermore, exposure to repetitive mild traumatic brain injuries exacerbated the apoE4-induced impairments in tau processing and elimination by astrocytes in apoE4 targeted-replacement mice. The diminished ability of apoE4 astrocytes to eliminate extracellular tau can lead to an accumulation of pathogenic tau, which induces mitochondrial dysfunction, as demonstrated by our studies. In total, our findings suggest that the apoE4 isoform lowers the threshold of astrocytic resilience to pathogenic tau, rendering them susceptible to bioenergetic deficits in the early stages of neurodegenerative diseases such as traumatic brain injury, potentially contributing to neurological decline.

Coding RNA expression profile and transcription factor analysis of H.pylori-associated chronic atrophic gastritis

PurposeAtrophic gastritis, one of the processes leading to gastric cancer (GC), is closely related to Helicobacter pylori (HP) infection. This study aimed to understand how HP causes chronic inflammation that leads to ulcers and stomach problems. MethodsTwenty-eight CAG patients were included in the study (9 HP-infected and 19 HP-uninfected). Endoscopy, histopathology, and high-throughput mRNA sequencing were performed. Differentially expressed genes (DEGs) were validated via qRT-PCR. ResultsPrincipal component analysis (PCA) results showed that more than 88.9 ​% of the samples were classified into the HP (+) group. A total of 157 DEGs were identified, of which 38 were up-regulated and 119 were down-regulated. The DEGs were mainly enriched in the biological process (BP) terms associated with immune system process, adaptive immune response, G protein-coupled receptor signaling pathway, as well as point to numerous key pathways, including fat digestion and absorption, retinol metabolism, steroid hormone biosynthesis, ascorbate and aldarate metabolism, and chemical carcinogenesis. APOA1, APOA4, FOXP3, NR1H4, ABCG5, ACTA1, CCL19, CCR7, CYP3A4, and PDCD had the highest degrees in protein–protein interaction network as the hub genes; they were also included into the transcription factor (TF)-target network except for PDCD. APOA1 and CYP3A4 were extremely significantly up-regulated in HP (+) CAG patients compared with the HP (−) CAG patients, while FOXP3, CCR7 and CCL19 were significantly down-regulated. ConclusionThe expression of APOA1, CYP3A4, FOXP3, CCR7, and CCL19 are the potential indicators for CAG to GC development, being the biomarkers to predict progression of CAG and poor prognosis of GC.

Apolipoprotein E deficiency attenuated osteogenesis via down-regulating osterix.

Apolipoprotein E (ApoE), a ligand for low-density lipoprotein receptors, is strongly induced during osteogenesis and has a physiologic role in regulating osteoblast function, but the mechanisms of its action are still unclear. The study aims to elucidate the influence and molecular mechanisms of ApoE on bone formation. An ovariectomy-induced osteoporotic model were conducted in ApoE knockout (ApoE-/-) mice to study the effect of ApoE on the bone system. Bone quality were assessed through bone mineral density and histomorphometric analysis. To investigate the underlying role and mechanisms of ApoE during osteogenesis, primary osteoblasts from the calvariums of newborn ApoE-/- or wild-type (WT) mice were cultured in the osteoblastic differentiation medium in vitro for further research. Our animal experiment data showed that ApoE-/- mice exhibited bone loss, exacerbated by estrogen deprivation after ovariectomy. ApoE deficiency attenuated osteoblast activity and inhibited osteoblast osteogenesis, accompanied by decreased osterix expression. ApoE deficiency did not affect primary osteoblast viability and collagen-1 expression. Moreover, osteoprotegerin expression in ApoE-/- osteoblasts was reduced compared to WT controls. Our study demonstrated that ApoE gene deficiency contributed to bone loss and attenuated osteogenesis by down-regulating osterix expression.

Endothelial Cell APOE3 Regulates Neurovascular, Neuronal, and Behavioral Function.

Specialized brain endothelial cells and human APOE3 are independently important for neurovascular function, yet whether APOE3 expression by endothelial cells contributes to brain function is currently unknown. In the present study, we determined whether the loss of endothelial cell APOE3 impacts brain vascular and neural function. We developed APOE3fl/fl/Cdh5(PAC)-CreERT2+/- (APOE3Cre+/-) and APOE3fl/fl/Cdh5(PAC)-CreERT2-/- (APOE3Cre-/-, control) mice and induced endothelial cell APOE3 knockdown with tamoxifen at ≈4 to 5 weeks of age. Neurovascular and neuronal function were evaluated by biochemistry, immunohistochemistry, behavioral testing, and electrophysiology at 9 months of age. We found that the loss of endothelial APOE3 expression was sufficient to cause neurovascular dysfunction including higher permeability and lower vessel coverage in tandem with deficits in spatial memory and fear memory extinction and a disruption of cortical excitatory/inhibitory balance. Our data collectively support the novel concept that endothelial APOE3 plays a critical role in the regulation of the neurovasculature, neural circuit function, and behavior.

ABCD1 Transporter Deficiency Results in Altered Cholesterol Homeostasis.

X-linked adrenoleukodystrophy (X-ALD), the most common peroxisomal disorder, is caused by mutations in the peroxisomal transporter ABCD1, resulting in the accumulation of very long-chain fatty acids (VLCFA). Strongly affected cell types, such as oligodendrocytes, adrenocortical cells and macrophages, exhibit high cholesterol turnover. Here, we investigated how ABCD1 deficiency affects cholesterol metabolism in human X-ALD patient-derived fibroblasts and CNS tissues of Abcd1-deficient mice. Lipidome analyses revealed increased levels of cholesterol esters (CE), containing both saturated VLCFA and mono/polyunsaturated (V)LCFA. The elevated CE(26:0) and CE(26:1) levels remained unchanged in LXR agonist-treated Abcd1 KO mice despite reduced total C26:0. Under high-cholesterol loading, gene expression of SOAT1, converting cholesterol to CE and lipid droplet formation were increased in human X-ALD fibroblasts versus healthy control fibroblasts. However, the expression of NCEH1, catalysing CE hydrolysis and the cholesterol transporter ABCA1 and cholesterol efflux were also upregulated. Elevated Soat1 and Abca1 expression and lipid droplet content were confirmed in the spinal cord of X-ALD mice, where expression of the CNS cholesterol transporter Apoe was also elevated. The extent of peroxisome-lipid droplet co-localisation appeared low and was not impaired by ABCD1-deficiency in cholesterol-loaded primary fibroblasts. Finally, addressing steroidogenesis, progesterone-induced cortisol release was amplified in X-ALD fibroblasts. These results link VLCFA to cholesterol homeostasis and justify further consideration of therapeutic approaches towards reducing VLCFA and cholesterol levels in X-ALD.

Olive oil increases the LIPC expression when associated with an Eastern pattern diet: An experimental study with Wistar rats

Some nutrigenomic effects of extra virgin olive oil (EVOO) are described in the literature; however, it is unknown whether its interaction with lipid-related genes is independent of the combined diet. In this sense, our objective was to investigate whether EVOO consumption associated with Western or Eastern human-based chow modulates the expression of APOE, APOB, and LIPC genes in rats. In view of this, the hypothesis is that the consumption of olive oil may not have the same nutrigenomic effects, depending on the diet consumed. For this study, 56 female rats were randomly divided into four groups: Western diet with EVOO (WS), Western-diet control (WC), Eastern-diet with EVOO (ES), and Eastern-diet control (EC). After 15 weeks, the animals were anesthetized with an intraperitoneal injection of chloral hydrate 15% (1.5 mL/kg) and euthanized by guillotining, and adipose tissue, liver, and blood were extracted. Triglycerides, cholesterol, and glucose levels were obtained following standard protocols, and relative gene expressions were calculated using the ΔΔCt method after quantitative PCR. The EVOO consumption was associated with LIPC gene expression increase in the liver only in animals fed the Eastern diet, compared to EC and WS animals. The EVOO consumption, combined with the Eastern diet, was associated with decreased triglyceride levels compared to WC. Although final weight and weight gain were similar between groups, WS animals had lower daily energy consumption. Conclusion: Given these results, the authors suggested that the EVOO nutrigenomic effects were restricted to an Eastern human-based diet.

Apolipoprotein A-I vascular gene therapy reduces vein-graft atherosclerosis

Coronary artery venous bypass grafts typically fail because of atherosclerosis driven by lipid and macrophage accumulation. Therapy for vein-graft atherosclerosis is limited to statin drugs, which are only modestly effective. We hypothesized that transduction of vein-graft endothelium of fat-fed rabbits with a helper-dependent adenovirus expressing apolipoprotein AI (HDAdApoAI) would reduce lipid and macrophage accumulation. Fat-fed rabbits received bilateral external jugular vein-to-carotid artery interposition grafts. Four weeks later, one graft per rabbit (n= 23 rabbits) was infused with HDAdApoAI and the contralateral graft with HDAdNull. Grafts were harvested 12weeks later. Paired analyses of grafts were performed, with vein graft cholesterol, intimal lipid, and macrophage content as the primary endpoints. HDAd genomes were detected in all grafts. APOAI mRNA was median 63-fold higher in HDAdApoAI grafts versus HDAdNull grafts (p<0.001). HDAdApoAI grafts had a mean 15% lower total cholesterol (by mass spectrometry; p= 0.003); mean 19% lower intimal lipid (by oil red O staining; p= 0.02); and mean 13% lower expression of the macrophage marker CD68 (by reverse transcriptase-mediated quantitative PCR; p= 0.008). Invivo transduction of vein-graft endothelium achieves persistent APOAI expression and reduces vein-graft cholesterol, intimal lipid, and CD68 expression. Vascular gene therapy with APOAI haspromise for preventing vein-graft failure caused by atherosclerosis.