ApoE mRNA Expression Research Articles

Decreased mRNA expression of NR1H3 and ABCA1 in pulmonary tuberculosis patients from population of Punjab, India.

Mycobacterium tuberculosis (MTB) is the causative organism of tuberculosis. Cholesterol is a crucial carbon source required for the survival of MTB in host cells. Transcription factor NR1H3 along with its important target genes ABCA1 and ApoE play important role in removal of extra cholesterol from cells. Changes in the gene expression of NR1H3, ABCA1 and ApoE can affect cholesterol homeostasis and thus the survival of MTB in host cells.Therefore, the present study was designed to analyze the mRNA expression of NR1H3, ABCA1 and ApoE in pulmonary TB (PTB) patients from the population of Punjab, India. In this study, mRNA expression of the transcription factor NR1H3 and its target genes ABCA1 and ApoE was analyzed in 89 subjects, including 41 PTB patients and 48 healthy controls (HCs) by real-time quantitative PCR. It was found that the mRNA expression of both NR1H3 and ABCA1 genes was significantly lower in TB patients than in HCs (p < 0.001). Even after sex-wise stratification of the subjects, mRNA expression of NR1H3 and ABCA1 was found to be down-regulated in both male and female TB patients. No significant difference was observed in expression of ApoE (p = 0.98). The present study found that the mRNA expression of NR1H3 and ABCA1 is down-regulated in TB patients from Punjab state of India.

Exploring the potential of VGLL3 methylation as a prognostic indicator for intracranial aneurysm with gender-specific considerations.

DNA methylation is widely recognized to play a role in intracranial aneurysm (IA) pathogenesis. We investigated the levels of methylation of vestigial-like 3 (VGLL3) in IA and explored its potential as a prognostic indicator. A total of 48 patients with IA and 48 healthy controls were included in the present study. Methylation levels of CpG sites were assessed using bisulfite pyrosequencing, and levels of VGLL3, TEAD, and YAP in the blood were measured by real-time quantitative polymerase chain reaction testing. VGLL3 methylation was significantly higher in controls than in IA patients (P=0.001), and this phenomenon was more pronounced in females (P<0.001). Compared with the control group, the expression levels of VGLL3 and TEAD in the blood of IA patients were significantly increased, while YAP was significantly decreased. VGLL3 methylation was positively correlated with HDL (P=0.003) and female Lpa concentration (r = 0.426, P=0.03), and was also negatively correlated with age (P=0.003), APOE (P=0.005), and VGLL3 mRNA expression (P<0.001). Methylation and mRNA expression of VGLL3 may serve as indicators of IA risk in females (AUC = 0.810 and 0.809). VGLL3 methylation may participate in the pathogenesis of IA by regulating the expression of the VGLL3/TEAD/YAP pathway, and its gene methylation and expression levels have IA risk prediction value.

Gene Expression Profiling as a Novel Diagnostic Tool for Neurodegenerative Disorders.

There is a lack of effective diagnostic biomarkers for neurodegenerative disorders (NDDs). Here, we established gene expression profiles for diagnosing Alzheimer's disease (AD), Parkinson's disease (PD), and vascular (VaD)/mixed dementia. Patients with AD had decreased APOE, PSEN1, and ABCA7 mRNA expression. Subjects with VaD/mixed dementia had 98% higher PICALM mRNA levels, but 75% lower ABCA7 mRNA expression than healthy individuals. Patients with PD and PD-related disorders showed increased SNCA mRNA levels. There were no differences in mRNA expression for OPRK1, NTRK2, and LRRK2 between healthy subjects and NDD patients. APOE mRNA expression had high diagnostic accuracy for AD, and moderate accuracy for PD and VaD/mixed dementia. PSEN1 mRNA expression showed promising accuracy for AD. PICALM mRNA expression was less accurate as a biomarker for AD. ABCA7 and SNCA mRNA expression showed high-to-excellent diagnostic accuracy for AD and PD, and moderate-to-high accuracy for VaD/mixed dementia. The APOE E4 allele reduced APOE expression in patients with different APOE genotypes. There was no association between PSEN1, PICALM, ABCA7, and SNCA gene polymorphisms and expression. Our study suggests that gene expression analysis has diagnostic value for NDDs and provides a liquid biopsy alternative to current diagnostic methods.

Regulation of astrocyte lipid metabolism and ApoE secretion by the microglial oxysterol, 25-hydroxycholesterol

Neuroinflammation, a major hallmark of Alzheimer’s disease and several other neurological and psychiatric disorders, is often associated with dysregulated cholesterol metabolism. Relative to homeostatic microglia, activated microglia express higher levels of Ch25h, an enzyme that hydroxylates cholesterol to produce 25-hydroxycholesterol (25HC). 25HC is an oxysterol with interesting immune roles stemming from its ability to regulate cholesterol metabolism. Since astrocytes synthesize cholesterol in the brain and transport it to other cells via ApoE-containing lipoproteins, we hypothesized that secreted 25HC from microglia may influence lipid metabolism as well as extracellular ApoE derived from astrocytes. Here, we show that astrocytes take up externally added 25HC and respond with altered lipid metabolism. Extracellular levels of ApoE lipoprotein particles increased after treatment of astrocytes with 25HC without an increase in Apoe mRNA expression. In mouse astrocytes-expressing human ApoE3 or ApoE4, 25HC promoted extracellular ApoE3 better than ApoE4. Increased extracellular ApoE was due to elevated efflux from increased Abca1 expression via LXRs as well as decreased lipoprotein reuptake from suppressed Ldlr expression via inhibition of SREBP. 25HC also suppressed expression of Srebf2, but not Srebf1, leading to reduced cholesterol synthesis in astrocytes without affecting fatty acid levels. We further show that 25HC promoted the activity of sterol-o-acyl transferase that led to a doubling of the amount of cholesteryl esters and their concomitant storage in lipid droplets. Our results demonstrate an important role for 25HC in regulating astrocyte lipid metabolism.

Combined with UPLC-Triple-TOF/MS-based plasma lipidomics and molecular pharmacology reveals the mechanisms of schisandrin against Alzheimer’s disease

BackgroundAlzheimer’s disease (AD), a type of neurodegeneration disease, is characterized by Aβ deposition and tangles of nerve fibers. Schisandrin is one of the main components of Fructus Schisandrae Chinensis. Researches showed that schisandrin can improve the cognitive impairment and memory of AD mice, but the specific mechanism has not been fully elucidated.PurposeThe purpose of this study is to investigate the possible mechanism of schisandrin in improving AD pathology.MethodsThe Morris water maze test was executed to detect spatial learning and memory. Ultra performance liquid chromatography-Triple time of flight mass spectrometry (UPLC-Triple-TOF/MS)-based plasma lipidomics was used to study the changes of plasma lipids. Moreover, we measured the levels of protein and mRNA expression of APOE and ABCA1 in the rat brains and in BV2 microglia.ResultsOur study found that schisandrin could improve learning and memory, and reduce Aβ deposition in AD rats. Furthermore, we found that schisandrin can improve plasma lipid metabolism disorders. Therefore, we hypothesized schisandrin might act via LXR and the docking results showed that schisandrin interacts with LXRβ. Further, we found schisandrin increased the protein and mRNA expression of LXR target genes APOE and ABCA1 in the brain of AD rats and in BV2 microglia.ConclusionOur study reveals the neuroprotective effect and mechanism of schisandrin improves AD pathology by activating LXR to produce APOE and ABCA1.

Bisphenol A disrupts apolipoprotein E expression through estrogen-related receptor gamma and DNA methlylation in the liver of male rare minnow Gobiocypris rarus

An increasing number of studies show that bisphenol A (BPA) can cause lipid metabolism disorder. However, few studies focused on the effect of BPA on lipid transport. Apolipoprotein E (ApoE) plays important roles in triglyceride (TG) transportation. Our previous study found that ApoE was a sensitive gene in response to BPA exposure in male rare minnow. To investigate the effect and mechanism of BPA on hepatic ApoE, adult male rare minnow Gobiocypris rarus were exposed to environmentally relevant concentrations of BPA (15 μg/L) for 1, 3 and 5 weeks. Results showed that BPA inhibited ApoE expression at week 1 and 5, while induced its expression at week 3. A positive estrogen-related receptor gamma (Esrrg) response element was identified in the promoter region of ApoE. The change of the Esrrg recruitment was consistent with ApoE mRNA expression. Moreover, the methylation status of the CpG sites near and on the Esrrg binding sites changed opposite to the ApoE mRNA level, which may be the main cause for the change in Esrrg recruitment. The expression of ApoE protein was significantly enhanced following long-term BPA exposure. Consistently, the TG accumulation was significantly increased in the plasma. The present study demonstrates that BPA could affect rare minnow ApoE expression, which is probably one of the ways for BPA disturbing fish lipid metabolism.

ApoE transiently regulates hippocampus amyloid-beta deposition to stable learning and memory ability in adult rats exposed in sevoflurane.

Post-operative cognitive dysfunction (POCD) is a common central nervous system complication after surgery. Inhaled anesthetic sevoflurane is thought to have harmful effects on the developing and aged nerves, but its effects on adults' nervous system are less studied and the mechanism is not clear. Male adult rats were divided into control group and sevoflurane group. Rats from sevoflurane group were received 3.2% sevoflurane + carrier gas (1L/min O2+1L/min air) for 2h, while control group received carrier gas for 2h. Each group was subsequently divided into 3 subgroups according to the Day 1, Day 3, Day 7 after sevoflurane anesthesia. Morris Water Maze, amyloid-beita (Abeta) and apolipoprotein E (ApoE) mRNA in hippocampus were analyzed. Then, adult ApoE-/- rats were also divided into control group and sevoflurane group. Each group was divided into 3 subgroups according to Day 1, Day 3 and Day 7. Abeta mRNA and protein expression in hippocampus were analyzed. Compared with the control group, hippocampal Abeta mRNA and protein expression in rats from sevoflurane group significantly increased in hippocampus on Day 7, while ApoE mRNA and protein expression increased on Day 1 and Day 3. There was no difference in times of crossing platforms, time during platform, times across platform quadrant and time percent during platform quadrant between each group. Compared with the control group, hippocampal Abeta and ApoE-/- rats in sevoflurane group did not change. ApoE modulates hippocampal Abeta deposition and stabilizes learning and memory ability in adult rats after sevoflurane exposure, but this effect is not constant.

Enrichment of Neurodegenerative Microglia Signature in Brain-Derived Extracellular Vesicles Isolated from Alzheimer's Disease Mouse Models.

Extracellular vesicles (EVs) are secreted by any neural cells in the central nervous system for molecular clearance, cellular communications, and disease spread in multiple neurodegenerative diseases, including Alzheimer’s disease (AD), although their exact molecular mechanism is poorly understood. We hypothesize that high-resolution proteomic profiling of EVs separated from animal models of AD would determine the composition of EV contents and their cellular origin. Here, we examined recently developed transgenic mice (CAST.APP/PS1), which express familial AD-linked mutations of amyloid precursor protein (APP) and presenilin-1 (PS1) in the CAST/EiJ mouse strain and develop hippocampal neurodegeneration. Quantitative proteomics analysis of EVs separated from CAST.APP/PS1 and age-matched control mice by tandem mass tag-mass spectrometry identified a total of 3444 unique proteins, which are enriched in neuron-, astrocyte-, oligodendrocyte-, and microglia-specific molecules. CAST.APP/PS1-derived EVs show significant enrichment of Psen1, APP, and Itgax and reduction of Wdr61, Pmpca, Aldh1a2, Calu, Anp32b, Actn4, and Ndufv2 compared to WT-derived EVs, suggesting the involvement of Aβ-processing complex and disease-associated/neurodegenerative microglia (DAM/MGnD) in EV secretion. In addition, Itgax and Apoe, DAM/MGnD markers, in EVs show a positive correlation with Itgax and Apoe mRNA expression from brain tissue in CAST.APP/PS1 mice. These datasets indicate the significant contribution of Aβ plaque and neurodegeneration-induced DAM/MGnD microglia for EV secretion in CAST.APP/PS1 mice and shed light on understanding AD pathogenesis.

MULTİPLE SKLEROZ HASTALARINDA APOE GEN EKSPRESYONUNUN BELİRLENMESİ

OBJECTIVE: Apolipoprotein E (ApoE) is a glycoprotein that functions as a ligand in receptor-mediated endocytosis of lipoprotein particles. There are studies showing the association of APOE with neurogenerative diseases such as Alzheimer's disease and multiple sclerosis (MS). The aim of this study was to investigate whether there is a relationship between APOE gene expression and MS.MATERIAL AND METHODS: To determine the effect of APOE gene expression on multiple sclerosis patients, we have included 35 MS patients and 20 healthy subjects into the study. The level of APOE mRNA expression was determined by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). For statistical analysis, t-test, chi-square test, Kruskal-Wallis test and Mann-Whitney U test were performed using SPSS package program and p &amp;lt;0.05 was considered as statistically significant.RESULTS: As a result, the comparison of ApoE gene expression in multiple sclerosis patients and healthy people using real-time PCR technique did not show any statistical significance between the groups (p=0.95).CONCLUSIONS: Our study does not support that ApoE gene expression may be related to MS. Further studies are needed to determine the role of ApoE in Multiple Sclerosis disease.

Neuroprotective Effects of the FGF21 Analogue LY2405319.

To date, there are no effective treatments for Alzheimer's disease (AD). Thus, a significant need for research of therapies remains. One promising pharmacological target is the hormone fibroblast growth factor 21 (FGF21), which is thought to be neuroprotective. A clinical candidate for medical use could be the FGF21 analogue LY2405319 (LY), which has a specificity and potency comparable to FGF21. The present study investigated the potential neuroprotective effect of LY via PPARγ/apoE/abca1 pathway, which is known to degrade amyloid-β (Aβ) plaques by using primary glial cells and hippocampal organotypic brain slice cultures (OBSCs) from 30- and 50-week-old transgenic APPswe/PS1dE9 (tg) mice. By LY treatment of 52-week-old tg mice with advanced Aβ deposition, we further aimed to elaborate the effect of LY on AD pathology in vivo. LY application to primary glial cells caused an upregulation of pparγ, apoE, and abca1 mRNA expression and significantly decreased number and area of Aβ plaques in OBSCs. LY treatment in tg mice increased cerebral [18F] FDG uptake and N-acetylaspartate/creatine ratio indicating enhanced neuronal activity and integrity. Although LY did not reduce the number of Aβ plaques in tg mice, the number of iba1-positive cells was significantly decreased indicating reduced microgliosis. These data identified LY in vitro as an activator of Aβ degrading genes leading to cerebral Aβ load amelioration in early and late AD pathology. Although Aβ plaque reduction by LY failed in vivo, LY may be used as therapeutic agent to treat AD-related neuroinflammation and impaired neuronal integrity.

Scutellaria barbata Flavonoids Improve the Composited Aβ-induced Abnormal Changes in Glial Cells of the Brains of Rats.

It has been reported that glial cells are involved in Alzheimer's disease (AD). In our previous research, Scutellaria barbata flavonoids (SBFs) were found to protect the AD-like rats from neuronal disorder and memory impairment; however, the effect of SBFs on the glial cells disorder in AD-like rats has been less studied. The effects of SBFs on astrocytes (ASs), microglial cells (MGs), and oligodendrocytes (Ols), as well as heat shock protein 70 (Hsp70) and apolipoprotein E (ApoE), were investigated in the present study. The successful model rats, screened by Morris water maze, were orally administrated daily with 35, 70, and 140 mg/kg SBFs for 36 d. The number of brain astrocytes (ASs), microglial cells (MGs), and oligodendrocytes (Ols) was examined by immunohistochemistry. The expressions of cortical glial fibrillary acidic protein (GFAP), leukocyte common antigen (LCA) (CD45), Claudin 11, and heat shock protein 70 (Hsp70) protein were assayed by Western blotting, and the expression of apolipoprotein E (ApoE) mRNA was analyzed by real-time quantitative polymerase chain reaction (qPCR). Compared with the sham-operated group, the number of ASs and MGs in the brain was significantly increased in the model group (P<0.05, P<0.01), accompanied by an increase in the expressions of GFAP, CD45, Hsp70 protein, and ApoE mRNA (P<0.05, P<0.01). Both Ols number and the expression of Claudin 11 protein decreased in the brain in the model group (P<0.05, P<0.01). However, the above-mentioned abnormal changes induced by composited Aβ were differently reversed by the treatment of SBFs at three doses of 35, 70, and 140 mg/kg (P<0.05, P<0.01). SBFs can dramatically improve the abnormal changes in glial cells of the brains of rats, induced by composited Aβ, which may be utilized as a helpful treatment for neurodegenerative diseases.

Identifying Blood Transcriptome Biomarkers of Alzheimer\u2019s Disease Using Transgenic Mice

The testing of pathological biomarkers of Alzheimer’s disease (AD), such as amyloid beta and tau, is time-consuming, expensive, and invasive. Here, we used 3xTg-AD mice to identify and validate putative novel blood transcriptome biomarkers of AD that can potentially be identified in the blood of patients. mRNA was extracted from the blood and hippocampus of 3xTg-AD and control mice at different ages and used for microarray analysis. Network and functional analyses revealed that the differentially expressed genes between AD and control mice modulated the immune and neuroinflammation systems. Five novel gene transcripts (Cdkn2a, Apobec3, Magi2, Parp3, and Cass4) showed significant increases with age, and their expression in the blood was collated with that in the hippocampus only in AD mice. We further assessed previously identified candidate biomarker genes. The expression of Trem1 and Trem2 in both the blood and brain was significantly increased with age. Decreased Tomm40 and increased Pink1 mRNA levels were observed in the mouse blood. The changes in the expression of Snca and Apoe mRNA in the mouse blood and brain were similar to those found in human AD blood. Our results demonstrated that the immune and neuroinflammatory system is involved in the pathophysiologies of aging and AD and that the blood transcriptome might be useful as a biomarker of AD.

Trem2 deficiency differentially affects phenotype and transcriptome of human APOE3 and APOE4 mice

BackgroundAlzheimer’s Disease (AD) is a neurodegenerative disorder influenced by aging and genetic risk factors. The inheritance of APOEε4 and variants of Triggering Receptor Expressed on Myeloid cells 2 (TREM2) are major genetic risk factors for AD. Recent studies showed that APOE binds to TREM2, thus raising the possibility of an APOE-TREM2 interaction that can modulate AD pathology.MethodsThe aim of this study was to investigate this interaction using complex AD model mice - a crossbreed of Trem2ko and APP/PSEN1dE9 mice expressing human APOE3 or APOE4 isoforms (APP/E3 and APP/E4 respectively), and their WT littermates (E3 and E4), and evaluate cognition, steady-state amyloid load, plaque compaction, plaque growth rate, glial response, and brain transcriptome.ResultsIn both, APP/E3 and APP/E4 mice, Trem2 deletion reduced plaque compaction but did not significantly affect steady-state plaque load. Importantly, the lack of TREM2 increased plaque growth that negatively correlated to the diminished microglia barrier, an effect most pronounced at earlier stages of amyloid deposition. We also found that Trem2 deficiency significantly decreased plaque-associated APOE protein in APP/E4 but not in APP/E3 mice in agreement with RNA-seq data. Interestingly, we observed a significant decrease of Apoe mRNA expression in plaque-associated microglia of APP/E4/Trem2ko vs APP/E4 mice. The absence of TREM2, worsened cognitive performance in APP transgenic mice but not their WT littermates.Gene expression analysis identified Trem2 signature - a cluster of highly connected immune response genes, commonly downregulated as a result of Trem2 deletion in all genotypes including APP and WT littermates. Furthermore, we identified sets of genes that were affected in TREM2- and APOE isoform-dependent manner. Among them were Clec7a and Csf1r upregulated in APP/E4 vs APP/E3 mice, a result further validated by in situ hybridization analysis. In contrast, Tyrobp and several genes involved in the C1Q complement cascade had a higher expression level in APP/E3 versus their APP/E4 counterparts.ConclusionsOur data demonstrate that lack of Trem2 differentially impacts the phenotype and brain transcriptome of APP mice expressing human APOE isoforms. The changes probably reflect the different effect of APOE isoforms on amyloid deposition.

The effects of aerobic training before and after the induction of Alzheimer's disease on ABCA1 and APOE mRNA expression and the level of soluble Aβ1-42 in the hippocampus of male Wistar rats.

Objective(s):The purpose of this study was to investigate the effects of aerobic training before and after the induction of Alzheimer’s disease on ABCA1 and APOE mRNA expression and the level of soluble Aβ1-42 in the hippocampus of male Wistar rats.Materials and Methods:Ninety six eight-week-old male Wistar rats were randomly divided into two groups: Training (n=48) and Rest (n=48). After four weeks, each group was randomly divided into two subgroups: intra-hippocampal injection of Aβ1-42 (n=24) and DMSO (n=24). Then, each group was again randomly divided into two groups: Training (n=12) and Rest (n=12). After four weeks, each group was again randomly divided into two groups: Behavioral test (n=7) and sacrificed (n=5). Results:The one-way ANOVA showed a significant increase in the mRNA expression of ABCA1 (P<0.05), a significant decrease in the level of soluble Aβ1-42, and no significant difference in the expression of APOE mRNA (P>0.05) in the hippocampus as a result of training. The analysis of the Morris water maze data showed that intra-hippocampal injection of Aβ1-42 impaired spatial learning and memory and exercise improved spatial learning (P<0.05) and memory (P<0.05).Conclusion:Therefore, aerobic training by a significant increase in the mRNA expression of ABCA1, which is the main factors of lipid metabolism in the brain and which is involved in the pathology of Alzheimer’s disease, can be consistent with improving cognitive function as an effective way of preventing and improving the symptoms of Alzheimer’s disease.

Typha angustifolia extract reduces diet-induced hyperlipidemia in rats

ObjectiveTo observe the lipid-lowering effect of Typha angustifolia extract (TAE) in Sprague Dawley rats. MethodsThe rats were randomly divided into six groups, including the hypercholesterolemic diet (HYD) group. Ad libitum food was given to the animals for 60 d to establish dyslipidemia models. The rats were received an ig administration of 1 mL medicine daily. After 120 d the animals were sacrificed by cervical dislocation; Blood was collected to measure total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), nitric oxide (NO), and endothelin (ET) plasma concentration; Livers were collected to measure ApoE mRNA and protein expression; Morphologic changes of aorta ventralis tissue were also observed. ResultsCompared with HYD group, TAE had the ability of reducing TC, TG, LDL-C, NO, and ET (P < 0.01), thereby increasing ApoE mRNA and protein expression of the liver (P < 0.01). ConclusionThese results suggested that TAE was capable of effectively decreasing the circulating lipids levels and enhancing the protective effects of artery.

P27. The fasting hormone FGF21-an alternative therapy for Alzheimer’s disease?

Background Lipolysis is regulated by PPAR α / γ and its target genes apoE and ABCA1, which not only control the transport of cholesterol but also the proteolytic degradation of A β -peptide (A β ) plaques, which are found to be deposited in increased number in Alzheimer’s disease (AD). Accordingly, it was shown that PPAR γ -activation stimulates A β -degradation, in an ABCA1- and apoE-dependent manner. Thus, it is reasonable to assume that increased lipolysis may be neuroprotective and could in part minimize the risk of developing dementia. Lipolysis is intensified during fasting, causing a rise in FGF21 levels, which also acts as a key mediator for PPAR α / γ . Therefore, we hypothesized that the FGF21-PPAR pathway may contribute to A β -clearance, via apoE and ABCA1. This in turn may enhance glucose metabolism, leading to improvements in cognition. Methods and results In line with this hypothesis, we were able to show in vitro that application of wild type FGF21 or an FGF21 Analogue (LY2405319; LY; Eli Lilly) to neurons as well as in glial cells, significantly increases mRNA expression of apoE and ABCA1. Application of LY to ex vivo brain slices of APPswe/PS1 Δ e9 (APP/PS1) mice, an AD-mouse model, reduces A β -plaques of up to 30% in comparison to control. These mice are also characterized by diminished glucose uptake in cognitive brain areas, as demonstrated by 18-FDG-positron emission tomography (FDG-PET). Interestingly, daily LY-application for 16 weeks augments central glucose metabolism in APP/PS1 mice, as indicated by an increased FDG uptake up to the value of control mice (C57BL6 mice). Conclusion Thus, we propose that FGF21 activates apoE/ABCA1-induced degradation of A β -plaques, leading to enhanced cognitive function, functionally evidenced by an increased glucose metabolism. Further experiments are necessary to evaluate FGF21 as a therapeutic option for treatment of AD. Funded by the German Research Foundation ( KU 3280/1-1 ).

A pleiotropic effect of the APOE gene: association of APOE polymorphisms with multibacillary leprosy in Han Chinese from Southwest China.

Patients with leprosy have a very low risk of Alzheimer disease (AD) and β-amyloid (Aβ) deposition is significantly lower in the brain tissue of elderly patients with leprosy compared with age-matched controls. Apolipoprotein E (ApoE) plays a critical role in lipid metabolic pathways and in the brain, facilitating the proteolytic clearance of Aβ. We hypothesized that APOE confers risk of leprosy as lipid metabolism is involved in Mycobacterium leprae infection. To investigate the potential genetic associations between APOE and leprosy in two independent Chinese case-control cohorts from the Yuxi and Wenshan prefectures, Yunnan Province of Southwest China. Five APOE single-nucleotide polymorphisms (SNPs) were analysed in 1110 individuals (527 patients and 583 controls) from the Yuxi prefecture using a SNaPshot assay. Genetic variations in the entire APOE exons were screened in 1788 individuals (798 patients and 990 controls) from the Wenshan prefecture using next-generation sequencing technology. The AD-associated SNPs rs405509 and rs439401 increased the risk of leprosy per se and multibacillary leprosy (P<0·005), but the APOE-ε4 allele did not. The SNPs rs405509 and rs439401 were cis expression quantitative trait loci (eQTL) for APOE expression in human skin. Differential APOE mRNA expression was observed in skin lesions of patients with type I reaction leprosy and those with multibacillary leprosy. APOE and related lipid genes are involved in an interaction network with leprosy susceptibility genes. The APOE gene is associated with leprosy, most likely by regulating lipid-metabolism-related genes.

Complement-Mediated Regulation of Apolipoprotein E in Cultured Human RPE Cells.

Purpose. Complement activation is implicated in the pathogenesis of age-related macular degeneration (AMD). Apolipoprotein E (ApoE) and complement activation products such as membrane attack complex (MAC) are present in eyes of individuals with AMD. Herein, we investigated the effect of complement activation on induction of ApoE accumulation in human retinal pigment epithelial (RPE) cells.Methods. Cultured human RPE cells were primed with a complement-fixing antibody followed by treatment with C1q-depleted (C1q-Dep) human serum to elicit alternative pathway complement activation. Controls included anti-C5 antibody-treated serum and heat-inactivated C1q-Dep. Total protein was determined on RPE cell extracts, conditioned media, and extracellular matrix (ECM) by Western blot. ApoE and MAC colocalization was assessed on cultured RPE cells and human eyes by immunofluorescent stain. ApoE mRNA expression was evaluated by quantitative PCR (qPCR).Results. Complement challenge upregulated cell-associated ApoE, but not apolipoprotein A1. ApoE accumulation was blocked by anti-C5 antibody and enhanced by repetitive complement challenge. ApoE mRNA levels were not affected by complement challenge. ApoE was frequently colocalized with MAC in complement-treated cells and drusen from human eyes. ApoE was released into complement-treated conditioned media after a single complement challenge and accumulated on ECM after repetitive complement challenge.Conclusions. Complement challenge induces time-dependent ApoE accumulation in RPE cells. An understanding of the mechanisms by which complement affects RPE ApoE accumulation may help to better explain drusen composition, and provide insights into potential therapeutic targets.

Effects of multiple exposures to sevoflurane anesthesia on expression of apolipoprotein E in hippocampus of neonatal rats

Objective To evaluate the effects of multiple exposures to sevoflurane anesthesia on the expression of apolipoprotein E (ApoE) in the hippocampus of neonatal rats. Methods Twenty-four pathogen-free Sprague-Dawley rats (12 males, 12 females), aged 7 days, weighing 15-20 g, were randomly divided into 2 groups (n=12 each) using a random number table: control group (group Con) and multiple exposures to sevoflurane anesthesia group (group Sev). On postnatal day 7, 14 and 21, 2.6% sevoflurane was inhaled for 2 h in group Sev, while the mixed gas of oxygen and air was inhaled instead of sevoflurane in group Con.Morris water maze test was carried out on postnatal day 31-37 to assess cognitive function.The rats were then sacrificed, and the hippocampus was removed to determine the expression of ApoE protein in hippocampal CA1, CA3 and DG regions (by immunohistochemistry) and the expression of ApoE mRNA (by fluorescent quantitative real-time reverse transcriptase polymerase chain reaction). Results There was no significant difference between the two groups in cognitive function (P>0.05). Compared with group Con, the expression of ApoE protein in hippocampal CA1 and CA3 regions and ApoE mRNA was significantly up-regulated in group Sev (P 0.05). Conclusion Multiple exposures to sevoflurane anesthesia can up-regulate the expression of hippocampal ApoE and produce mild neurotoxicity without causing changes in cognitive function in neonatal rats. Key words: Anesthetics, inhalation; Infant, newborn; Drug toxicity; Apolipoproteins E; Hippocampus

Effect of sevoflurane anesthesia on expression of hippocampal apolipoprotein E mRNA of rats

Objective To investigate the effect of sevoflurane anesthesia on the expression of hippocampal apolipoprotein E (ApoE) mRNA of rats. Methods Sixty healthy male Sprague-Dawley rats, weighing 300-400 g, aged 15 weeks, were randomly divided into 2 groups (n=30 each) using a random number table: 50% oxygen group (group C) and 3.2% sevoflurane group (group S). The rats in group C inhaled 50% oxygen for 2 h, while those in group S inhaled 3.2% sevoflurane in 50% oxygen for 2 h. Morris water maze test was carried out before anesthesia and at 24 and 72 h after anesthesia. At 2, 24 and 72 h after anesthesia, hippocampal specimens were obtained for determination of the expression of ApoE mRNA by RT-PCR. Results Compared with group C, no significant change was found in the escape latency, time of staying at the original platform quadrant, frequency of crossing the original platform, and swimming distance before and after anesthesia, and the expression of ApoE mRNA was up-regulated after anesthesia in group S. There was no significant difference in the escape latency, time of staying at the original platform quadrant, frequency of crossing the original platform, and swimming distance before and after anesthesia, and expression of ApoE mRNA at each time point after anesthesia between the two groups. Conclusion Cognitive dysfunction induced by sevoflurane has no relationship with the up-regulated expression of ApoE mRNA in the hippocampus of rats. Key words: Anesthetics, inhalation; Cognition disorders; Apolipoproteins E