胃肠道饱感信号——Apolipoprotein A-IV的研究进展

阿朴脂蛋白A-IV(apoA-IV)作为一种载脂蛋白,是调节血浆脂蛋白代谢家族中最大的成员。在哺乳动物中,apoA-IV主要是由小肠绒毛上皮细胞在脂肪吸收时合成,然后通过刚合成的乳糜微粒表面进入循环。apoA-IV在人类和啮齿类动物肠道中广泛存在,主要由小肠和肝脏分泌,其合成和分泌受乳糜微粒合成、PYY、Leptin等多种因素的影响。并且其生理作用众多,除了调节小肠脂肪的吸收和乳糜微粒的组装,对动物摄食、胃排空及脂肪氧化等都有抑制作用,此外,还能增加低密度脂蛋白胆固醇的循环,减少动脉粥样硬化的进程等。文中仅对apoA-IV在小肠的合成和分泌的调控及其在摄食方面的作用进行综述。

溶解素E1、可诱导共刺激分子、载脂蛋白A-IV在甲状腺功能减退症患者血清中的表达及相关性

目的探究甲状腺功能减退症(甲减)患者血清中溶解素E1(RvE1)、可诱导共刺激分子(ICOS)、载脂蛋白A-IV(Apo-AIV)表达水平,并分析其与疾病的相关性。方法选择2023年5月-2024年5月本院收治的234例甲减患者作为甲减组,另选同期240名甲状腺功能正常体检者作为对照组。依据垂体促甲状腺激素(TSH)及游离甲状腺素(FT4)水平将甲减组分为亚临床甲减组(103例)及临床甲减组(131例)。采用酶联免疫吸附法(ELISA)检测血清RvE1、ICOS、Apo-AIV水平,比较不同类型甲减患者甲状腺激素及血清RvE1、ICOS、Apo-AIV水平,采用Pearson法相关性分析血清RvE1、ICOS、Apo-AIV水平与甲状腺激素水平的相关性,采用多因素Logistic回归分析甲减发生的影响因素,采用受试者工作特征(ROC)曲线分析血清RvE1、ICOS、Apo-AIV水平对甲减的诊断价值。结果甲减组血清RvE1水平及游离三碘甲状腺原氨酸(FT3)、FT4水平低于对照组,血清ICOS、Apo-AIV水平及TSH水平高于对照组(P<0.05);亚临床甲减组患者血清RvE1水平及FT3、FT4水平高于临床甲减组,血清ICOS、Apo-AIV水平及TSH水平低于临床甲减组(P<0.05);血清RvE1水平与FT3、FT4水平正相关,与TSH水平负相关,血清ICOS、Apo-AIV水平与FT3、FT4水平负相关,与TSH水平正相关(P<0.05);血清RvE1(95%CI=0.464~0.692)、ICOS(95%CI=2.772~35.012)、Apo-AIV(95%CI=2.977~13.154)水平及FT3(95%CI=0.623~0.966)、FT4(95%CI=0.448~0.921)、TSH(95%CI=1.827~14.701)水平是甲减发生的影响因素(P<0.05);血清RvE1、ICOS、Apo-AIV水平联合诊断甲减发生的曲线下面积(AUC)高于血清RvE1水平单独诊断的AUC(Z=2.601,P=0.009),高于血清ICOS水平单独诊断的AUC(Z=7.638,P<0.05),高于血清Apo-AIV水平单独诊断的AUC(Z=5.391,P<0.05)。结论甲减患者血清RvE1水平降低,血清ICOS、Apo-AIV水平升高,与甲状腺激素水平相关,联合诊断甲减的价值较高。

Impact of apolipoprotein E isoforms on sporadic Alzheimer's disease:beyond the role of amyloid beta

The impact of apolipoprotein E(ApoE)isoforms on sporadic Alzheimer's disease has long been studied;however,the influences of apolipoprotein E gene(APOE)on healthy and pathological human brains are not fully understood.ApoE exists as three common isoforms(ApoE2,ApoE3,and ApoE4),which differ in two amino acid residues.Traditionally,ApoE binds cholesterol and phospholipids and ApoE isoforms display diffe rent affinities for their receptors,lipids transport and distribution in the brain and periphery.The role of ApoE in the human depends on ApoE isoforms,brain regions,aging,and neural injury.APOE E4 is the strongest genetic risk factor for sporadic Alzheimer's disease,considering its role in influencing amyloid-beta metabolism.The exact mechanisms by which APOE gene variants may increase or decrease Alzheimer's disease risk are not fully understood,but APOE was also known to affect directly and indirectly tau-mediated neurodegeneration,lipids metabolism,neurovascular unit,and microglial function.Consistent with the biological function of ApoE,ApoE4 isoform significantly alte red signaling pathways associated with cholesterol homeostasis,transport,and myelination.Also,the rare protective APOE variants confirm that ApoE plays an important role in Alzheimer's disease pathogenesis.The objectives of the present mini-review were to describe classical and new roles of various ApoE isoforms in Alzheimer's disease pathophysiology beyond the deposition of amyloid-beta and to establish a functional link between APOE,brain function,and memory,from a molecular to a clinical level.APOE genotype also exerted a heterogeneous effect on clinical Alzheimer's disease phenotype and its outcomes.Not only in learning and memory but also in neuro psychiatric symptoms that occur in a premorbid condition.Cla rifying the relationships between Alzheimer's disease-related pathology with neuropsychiatric symptoms,particularly suicidal ideation in Alzheimer's disease patients,may be useful for elucidating also the underlying pathophysiological process and its prognosis.Also,the effects of anti-amyloid-beta drugs,recently approved for the treatment of Alzheimer's disease,could be influenced by the APOE genotype.

27-Hydroxycholesterol/liver X receptor/apolipoprotein E mediates zearalenone-induced intestinal immunosuppression:A key target potentially linking zearalenone and cancer

Zearalenone(ZEN)is a mycotoxin that extensively contaminates food and feed,posing a significant threat to public health.However,the mechanisms behind ZEN-induced intestinal immunotoxicity remain unclear.In this study,Sprague-Dawley(SD)rats were exposed to ZEN at a dosage of 5 mg/kg/day b.w.for a duration of 14 days.The results demonstrated that ZEN exposure led to notable pathological alterations and immunosuppression within the intestine.Furthermore,ZEN exposure caused a significant reduction in the levels of apolipoprotein E(ApoE)and liver X receptor(LXR)(P<0.05).Conversely,it upregulated the levels of myeloid-derived suppressor cells(MDSCs)markers(P<0.05)and decreased the presence of 27-hydroxycholesterol(27-HC)in the intestine(P<0.05).It was observed that ApoE or LXR agonists were able to mitigate the immunosuppressive effects induced by ZEN.Additionally,a bioinformatics analysis highlighted that the downregulation of ApoE might elevate the susceptibility to colorectal,breast,and lung cancers.These findings underscore the crucial role of the 27-HC/LXR/ApoE axis disruption in ZEN-induced MDSCs proliferation and subsequent inhibition of T lymphocyte activation within the rat intestine.Notably,ApoE may emerge as a pivotal target linking ZEN exposure to cancer development.

Hepatocyte growth factor enhances the ability of dental pulp stem cells to ameliorate atherosclerosis in apolipoprotein E-knockout mice

BACKGROUND Atherosclerosis(AS),a chronic inflammatory disease of blood vessels,is a major contributor to cardiovascular disease.Dental pulp stem cells(DPSCs)are capable of exerting immunomodulatory and anti-inflammatory effects by secreting cytokines and exosomes and are widely used to treat autoimmune and inflam-mation-related diseases.Hepatocyte growth factor(HGF)is a pleiotropic cytokine that plays a key role in many inflammatory and autoimmune diseases.AIM To modify DPSCs with HGF(DPSC-HGF)and evaluate the therapeutic effect of DPSC-HGF on AS using an apolipoprotein E-knockout(ApoE-/-)mouse model and an in vitro cellular model.METHODS ApoE-/-mice were fed with a high-fat diet(HFD)for 12 wk and injected with DPSC-HGF or Ad-Null modified DPSCs(DPSC-Null)through tail vein at weeks 4,7,and 11,respectively,and the therapeutic efficacy and mechanisms were analyzed by histopathology,flow cytometry,lipid and glucose measurements,real-time reverse transcription polymerase chain reaction(RT-PCR),and enzyme-linked immunosorbent assay at the different time points of the experiment.An in vitro inflammatory cell model was established by using RAW264.7 cells and human aortic endothelial cells(HAOECs),and indirect co-cultured with supernatant of DPSC-Null(DPSC-Null-CM)or DPSC-HGF-CM,and the effect and mechanisms were analyzed by flow cytometry,RT-PCR and western blot.Nuclear factor-κB(NF-κB)activators and inhibitors were also used to validate the related signaling pathways.RESULTS DPSC-Null and DPSC-HGF treatments decreased the area of atherosclerotic plaques and reduced the expression of inflammatory factors,and the percentage of macrophages in the aorta,and DPSC-HGF treatment had more pronounced effects.DPSCs treatment had no effect on serum lipoprotein levels.The FACS results showed that DPSCs treatment reduced the percentages of monocytes,neutrophils,and M1 macrophages in the peripheral blood and spleen.DPSC-Null-CM and DPSC-HGF-CM reduced adhesion molecule expression in tumor necrosis factor-αstimulated HAOECs and regulated M1 polarization and inflammatory factor expression in lipopolysaccharide-induced RAW264.7 cells by inhibiting the NF-κB signaling pathway.CONCLUSION This study suggested that DPSC-HGF could more effectively ameliorate AS in ApoE-/-mice on a HFD,and could be of greater value in stem cell-based treatments for AS.

New insights into ATR inhibition in muscle invasive bladder cancer:The role of apolipoprotein B mRNA editing catalytic subunit 3B

Background:Apolipoprotein B mRNA editing catalytic polypeptide(APOBEC),an endogenous mutator,induces DNA damage and activates the ataxia telangiectasia and Rad3-related(ATR)-checkpoint kinase 1(Chk1)pathway.Although cisplatin-based therapy is the mainstay for muscle-invasive bladder cancer(MIBC),it has a poor survival rate.Therefore,this study aimed to evaluate the efficacy of an ATR inhibitor combined with cisplatin in the treatment of APOBEC catalytic subunit 3B(APOBEC3B)expressing MIBC.Methods:Immunohistochemical staining was performed to analyze an association between APOBEC3B and ATR in patients with MIBC.The APOBEC3B expression in MIBC cell lines was assessed using real-time polymerase chain reaction and western blot analysis.Western blot analysis was performed to confirm differences in phosphorylated Chk1(pChk1)expression according to the APOBEC3B expression.Cell viability and apoptosis analyses were performed to examine the anti-tumor activity of ATR inhibitors combined with cisplatin.Results:There was a significant association between APOBEC3B and ATR expression in the tumor tissues obtained from patients with MIBC.Cells with higher APOBEC3B expression showed higher pChk1 expression than cells expressing low APOBEC3B levels.Combination treatment of ATR inhibitor and cisplatin inhibited cell growth in MIBC cells with a higher APOBEC3B expression.Compared to cisplatin single treatment,combination treatment induced more apoptotic cell death in the cells with higher APOBEC3B expression.Conclusion:Our study shows that APOBEC3B’s higher expression status can enhance the sensitivity of MIBC to cisplatin upon ATR inhibition.This result provides new insight into appropriate patient selection for the effective application of ATR inhibitors in MIBC.

Role of apolipoproteins,ABCA1 and LCAT in the biogenesis of normal and aberrant high density lipoproteins

In this review, we focus on the pathway of biogenesis of HDL, the essential role of apoA-I, ATP binding cassette transporter A1（ABCA1）, and lecithin： cholesterol acyltransferase（LCAT） in the formation of plasma HDL; the generation of aberrant forms of HDL containing mutant apoA-I forms and the role of apoA-IV and apoE in the formation of distinct HDL subpopulations. The biogenesis of HDL requires functional interactions of the ABCA1 with apoA-I（and to a lesser extent with apoE and apoA-IV） and subsequent interactions of the nascent HDL species thus formed with LCAT. Mutations in apoA-I, ABCA1 and LCAT either prevent or impair the formation of HDL and may also affect the functionality of the HDL species formed. Emphasis is placed on three categories of apoA-I mutations. The first category describes a unique bio-engineered apoA-I mutation that disrupts interactions between apoA-I and ABCA1 and generates aberrant prep HDL subpopulations that cannot be converted efficiently to a subpopulations by LCAT. The second category describes natural and bio-engineered apoA-I mutations that generate preβ and small size a4 HDL subpopulations, and are associated with low plasma HDL levels. These phenotypes can be corrected by excess LCAT. The third category describes bio-engineered apoA-I mutations that induce hypertriglyceridemia that can be corrected by excess lipoprotein lipase and also have defective maturation of HDL.The HDL phenotypes described here may serve in the future for diagnosis, prognoses and potential treatment of abnormalities that affect the biogenesis and functionality of HDL.

The Effects of Apolipoprotein E Polymorphism on Serum Lipids, Lipoproteins and Apolipoproteins Variation

Objective: To study the effects of Apolipoprotein E (ApoE) polymorphism onserum levels of lipids, lipoproteins and apolipoproteins. Methods: Fragments of ApoE gene forthex-on containing codon 112 and 158 polymorphic locus were amplified by PCR, and then digested untilCfo I endonuclease. Genotypes and alleles frequencies of 168 healthy persons in Jiangsu area werecalculated. The effects of ApoE genotypes and alleles on serum lipids, lipoproteins andapolipoproteins variation were analyzed. Results: The effects of ApoE alleles on total cholesterol(TC), law density lipoprotein-cholesterol (LDL-C), ApoB was: along a decreasing gradientε_4>ε_3>ε_2. The effect of ε_4 allele was to increase serum levels of TC, LDL-C and ApoB, andthe ε_2 allele had an effect opposite to that of ε_4 allele. Conclusion: ApoE polymorphism is anindependent genetic factor on individual serum levels of lipids and apolipoproteins.

膳食营养素摄入对人血清载脂蛋白A-IV水平的影响

目的:探讨膳食摄入对血清apoA-IV水平的影响,以进一步阐明apoA-IV调节摄食和能量平衡的作用机理。方法:选取山东省淄博市农村和济南市社区居民389例,采用酶联免疫吸附法(ELISA)检测空腹12 h血清apoA-IV的水平;采用3 d膳食记录法获得膳食摄入量。所有数据使用SPSS12.0版软件进行分析。结果:apoA-IV水平与脂肪、膳食纤维、碳水化合物、蛋白质摄入量呈负相关关系(P<0.05),高脂膳食者血清apoA-IV水平显著低于低脂膳食者(P<0.05)。结论:高脂肪摄入是影响血清apoA-IV水平的主要因素。

Liver as a new target organ in Alzheimer's disease:insight from cholesterol metabolism and its role in amyloid-beta clearance

Alzheimer's disease,the primary cause of dementia,is characterized by neuropathologies,such as amyloid plaques,synaptic and neuronal degeneration,and neurofibrillary tangles.Although amyloid plaques are the primary characteristic of Alzheimer's disease in the central nervous system and peripheral organs,targeting amyloid-beta clearance in the central nervous system has shown limited clinical efficacy in Alzheimer's disease treatment.Metabolic abnormalities are commonly observed in patients with Alzheimer's disease.The liver is the primary peripheral organ involved in amyloid-beta metabolism,playing a crucial role in the pathophysiology of Alzheimer's disease.Notably,impaired cholesterol metabolism in the liver may exacerbate the development of Alzheimer's disease.In this review,we explore the underlying causes of Alzheimer's disease and elucidate the role of the liver in amyloid-beta clearance and cholesterol metabolism.Furthermore,we propose that restoring normal cholesterol metabolism in the liver could represent a promising therapeutic strategy for addressing Alzheimer's disease.

Triglyceride levels and apolipoprotein E polymorphism in patients with acute pancreatitis

BACKGROUND:Hypertriglyceridemia is an unusual cause of acute pancreatitis and sometimes considered to be an epiphenomenon.This study aimed to investigate the clinical and analytical features and the APOE genotypes in patients with acute pancreatitis and severe hypertriglyceridemia.METHODS:We undertook a one-year,prospective study of patients with acute pancreatitis whose first laboratory analysis on admission to the emergency department included measurement of serum triglycerides.The APOE genotype was determined and the patients answered an established questionnaire within the first 24 hours concerning their alcohol consumption,the presence of co-morbidities and any medications being taken.The patients’ progression,etiological diagnosis,hospital stay and clinical and radiological severity were all recorded.RESULTS:Hypertriglyceridemia was responsible for 7 of 133 cases of pancreatitis (5%);the remaining cases were of biliary (53%),idiopathic (26%),alcoholic (11%) or other (5%) origin.Compared with these remaining cases,the patients with hypertriglyceridemia were significantly younger,had more relapses,and more often had diabetes mellitus.They usually consumed alcohol or consumed it excessively on the days before admission.Also,the ε4 allele of the APOE gene was more common in this group (P<0.05).CONCLUSION:One of 20 episodes of acute pancreatitis is caused by hypertriglyceridemia and it is linked to genetic (ε4 allele) and comorbid factors such as diabetes and,especially,alcohol consumption.

XbaⅠpolymorphisms of apolipoprotein B gene:Another risk factor of gallstone formation after radical gastrectomy

AIM:To prospectively investigate the association between the XbaⅠpolymorphisms of apolipoprotein B (APOB)gene and gallstone formation following gastrectomy.METHODS:The study was conducted between January 2005 and December 2006.A total of 186 gastric cancer patients who had undergone radical gastrectomy were grouped according to XbaⅠpolymorphisms of APOB gene(X+X-group,n=24 and X-X-group,n =162)and compared.The XbaⅠpolymorphisms of APOB gene were detected by polymerase chain reaction-restriction fragment length polymorphism(PCRRFLP).RESULTS:The incidence of gallstone was significantly higher in the X + X-group than in the X-X-group[54.2% vs 9.3%,RR=5.85(2.23-15.32),P<0.001].The serum levels of total cholesterol(TC)and low-density lipoprotein(LDL)were higher in the X + X-than in the X-X-group(4.02±1.12 vs 3.48±0.88,P=0.004 before surgery and 3.88±1.09 vs 3.40±0.86,P=0.008 after surgery).LDL was 2.21±0.96 vs 1.89±0.84(P =0.042)before surgery and 2.09±0.95 vs 1.72±0.85 (P=0.029)after surgery in the two groups.No relationship was found between XbaⅠpolymorphisms and gallbladder motility.CONCLUSION:In Chinese patients after radical gastrectomy,X + allele of APOB gene is another risk factor for the development of gallstone besides the gallbladder motility disorder after surgery.

C-reactive Protein Level,Apolipoprotein B-to-apolipoprotein A-1 Ratio,and Risks of Ischemic Stroke and Coronary Heart Disease among Inner Mongolians in China

Objective We aimed to investigate the cumulative effect of high CRP level and apolipoprotein B-to-apolipoprotein A-1（ApoB/ApoA-1） ratio on the incidence of ischemic stroke（IS） or coronary heart disease（CHD） in a Mongolian population in China.Methods From June 2003 to July 2012,2589 Mongolian participants were followed up for IS and CHD events based on baseline investigation.All the participants were divided into four subgroups according to C-reactive protein（CRP） level and ApoB/ApoA-1 ratio.Cox proportional hazard models were used to estimate the hazard ratios（HRs） and 95% confidence intervals（CIs） for the IS and CHD events in all the subgroups.Results The HRs（95% CI） for IS and CHD were 1.33（0.84-2.12）,1.14（0.69-1.88）,and 1.91（1.17-3.11） in the ‘low CRP level with high ApoB/ApoA-1＇,‘high CRP level with low ApoB/ApoA-1＇,and ‘high CRP level with high ApoB/ApoA-1＇ subgroups,respectively,in comparison with the ‘low CRP level with low ApoB/ApoA-1＇ subgroup.The risks of IS and CHD events was highest in the ‘high CRP level with high ApoB/ApoA-1＇ subgroup,with statistical significance.Conclusion High CRP level with high ApoB/ApoA-1 ratio was associated with the highest risks of IS and CHD in the Mongolian population.This study suggests that the combination of high CRP and ApoB/ApoA-1 ratio may improve the assessment of future risk of developing IS and CHD in the general population.

Apolipoprotein C3(-455T>C) polymorphism confers susceptibility to nonalcoholic fatty liver disease in the Southern Han Chinese population

AIM:To investigate the relationship between Apolipoprotein C3(APOC3)(-455T>C) polymorphism and nonalcoholic fatty liver disease(NAFLD) in the Southern Chinese han population.METHODS:In this prospective case-control study,we recruited 300 NAFLD patients and 300 healthy controls to a cohort representing Southern Chinese han population at The First Affiliated Hospital,Sun Yat-sen University,from January to December 2012. Polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing were used to genotype the APOC3(-455T>C) variants.RESULTS:After adjusting for age,gender,and bodymass index,TC and CC genotypes were found to increase the susceptibility to NAFLD compared to the TT genotype,with adjusted odds ratios(ORs) of 1.77(95%CI:1.16-2.72) and 2.80(95%CI:1.64-4.79),respectively. Further stratification analysis indicated that carriers of the CC genotype was more susceptible to insulin resistance(IR) than those of the TT genotype,with an OR of 3.24(95%CI:1.52-6.92). The CC genotype also was associated with a significantly higher risk of hypertension,hypertriglyceridemia,and low levels of high-density lipoprotein cholesterol(hDL)(P < 0.05). No association was found between the APOC3(-455T>C) polymorphism and obesity,impaired glucose tolerance,hyperuricemia,hypercholesterolemia,or high levels of low-density lipoprotein cholesterol(LDL)(P > 0.05).CONCLUSION:APOC3(-455T>C) genetic variation is involved in the susceptibility to developing NAFLD,IR,hypertension,hypertriglyceridemia,and low hDL in the Southern Chinese han population.

Autoantibodies to apolipoprotein A-1 as a biomarker of cardiovascular autoimmunity

Immune-driven inflammation plays an important part inatherogenesis and is therefore believed to be key to thedevelopment of cardiovascular disease(CVD), whichis currently the leading cause of death in the Westernworld. By fulfilling some of the Koch postulates, athero-genesis has even been proposed to be considered as anautoimmune disease, raising the hope that CVD couldbe prevented by immunomodulation. Nevertheless,the role of the immune system and autoimmune reac-tions in atherosclerosis appear to be a double edged-sword, with both pro-atherogenic and anti-atherogenicattributes. Hence, if immunomodulation is to becomea therapeutic option for atherosclerosis and CVD, it willbe crucial to correctly identify patients who might ben-efit from targeted suppression of deleterious autoim-mune responses. This could be achieved, for example, by the detection of disease-associated autoantibodies. In this work, we will review the currently available clini-cal, in vitro, and animal studies dedicated to autoan-tibodies against apolipoprotein A-1(anti-apoA-1 IgG), the major proteic fraction of high density lipoprotein. Current clinical studies indicate that high levels of anti-apoA-1 IgG are associated with a worse cardiovascular prognosis. In addition, in vitro and animal studies indi-cate a pro-inflammatory and pro-atherogenic role, sup-porting the hypothesis that these autoantibodies may play a direct causal role in CVD, and furthermore that they could potentially represent a therapeutic target for CVD in the future.

Genetic association of apolipoprotein E polymorphisms with inflammatory bowel disease

AIM:To study the association of apolipoprotein E(APOE) polymorphisms with the susceptibility ofinflammatory bowel disease(IBD) in Saudi patients.METHODS:APOE genotyping was performed to evaluate the allele and genotype frequencies in 378 Saudi subjects including IBD patients with ulcerative colitis(n = 84) or Crohn's disease(n = 94) and matched controls(n = 200) using polymerase chain reaction and reverse-hybridization techniques.RESULTS:The frequencies of the APOE ε2 allele and ε2/ε3 and ε2/ε4 genotypes were significantly higher in IBD patients than in controls(P < 0.05),suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to IBD.On the contrary,the frequencies of the ε3 allele and ε3/ε3 genotype were lower in IBD patients as compared to controls,suggesting a protective effect of APOE ε3 for IBD.The prevalence of the ε4 allele was also higher in the patient group compared to controls,suggesting that the ε4 allele may also increase the risk of IBD.Our results also indicated that the APOE ε4 allele was associated with an early age of IBD onset.No effect of gender or type of IBD(familial or sporadic) on the frequency distribution of APOE alleles and genotypes was noticed in this study.CONCLUSION:APOE polymorphism is associated with risk of developing IBD and early age of onset in Saudi patients,though further studies with a large-size population are warranted.

Apolipoprotein E polymorphisms increase the risk of post-stroke depression

Recent reports have shown that apolipoprotein E （APOE） polymorphisms are involved in neurodegenerative disease. However, it is unclear whether APOE affects post-stroke depression. Accordingly, we hypothesized that APOE polymorphisms modify the risk of post-stroke depression. Here, we performed a hospital-based case-control study （including 76 cerebral infarction cases with post-stroke depression, 88 cerebral infarction cases without post-stroke depression, and 109 controls without any evidence of post-stroke depression or cerebral infarction） to determine possible association between APOE rs429358 and rs7412 polymorphisms and risk of post-stroke depression. Our findings show no difference among the groups with regards genotype distribution of the rs7412 polymorphism. In contrast, APOE genotypes with rs429358-C alleles increased the risk of post-stroke depression. Further, the rs429358 polymorphism was associated with significantly decreased regional cerebral blood flow values in the left temporal lobe of post-stroke depression cases. Additionally, the rs429358 polymorphism was not only associated with depression severity, but with increasing serum levels of total cholesterol. These resuits suggest that the APOE rs429358 polymorphism is associated with increased risk of developing post-stroke depression, and that APOE rs429358-C allele genotypes may be detrimental to recovery of nerve function after stoke. Indeed, these findings provide clinical data for future post-stroke depression gene interventions.

High levels of homocysteine downregulate apolipoprotein E expression via nuclear factor kappa B

AIM: To investigate the effect of high homocysteine(Hcy) levels on apolipoprotein E(apoE) expression and the signaling pathways involved in this gene regulation.METHODS: Reverse transcriptase polymerase chain reaction(RT-PCR) and Western blot were used to assess apo E expression in cells treated with various concentrations(50-500 μmol/L) of Hcy. Calcium phosphatetransient transfections were performed in HEK-293 and RAW 264.7 cells to evaluate the effect of Hcy on apoE regulatory elements [promoter and distal multienhancer 2(ME2)]. To this aim, plasmids containing the proximal apoE promoter [(-500/+73)apoE construct] alone or in the presence of ME2 [ME2/(-500/+73)apoE construct] to drive the expression of the reporter luciferase gene were used. Co-transfection experiments were carried out to investigate the downstream effectors of Hcymediated regulation of apoE promoter by using specific inhibitors or a dominant negative form of IKβ. In other co-transfections, the luciferase reporter was under the control of synthetic promoters containing multiple specific binding sites for nuclear factor kappa B(NF-κB), activator protein-1(AP-1) or nuclear factor of activated T cells(NFAT). Chromatin immunoprecipitation(ChI P)assay was accomplished to detect the binding of NF-κB p65 subunit to the apoE promoter in HEK-293 treated with 500 μmol/L Hcy. As control, cells were incubated with similar concentration of cysteine. NF-κB p65 proteins bound to DNA were immunoprecipitated with anti-p65 antibodies and DNA was identified by PCR using primers amplifying the region-100/+4 of the apoE gene. RESULTS: RT-PCR revealed that high levels of Hcy(250-750 μmol/L) induced a 2-3 fold decrease in apoE m RNA levels in HEK-293 cells, while apo E gene expression was not significantly affected by treatment with lower concentrations of Hcy(100 μmol/L). Immunoblotting data provided additional evidence for the negative role of Hcy in apoE expression. Hcy decreased apoE promoter activity, in the presence or absence of ME2, in a dose dependent manner, in both RAW 264.7 and HEK-293 cells, as revealed by transient transfection experiments. The downstream effectors of the signaling pathways of Hcy were also investigated. The inhibitory effect of Hcy on the apo E promoter activity was counteracted by MAPK/ERK kinase 1/2(MEK1/2) inhibitor U0126, suggesting that MEK1/2 is involved in the downregulation of apoE promoter activity by Hcy. Our data demonstrated that Hcy-induced inhibition of apoE took place through activation of NF-κB. Moreover, we demonstrated that Hcy activated a synthetic promoter containing three NF-κB binding sites, but did not affect promoters containing AP-1 or NFAT binding sites. ChI P experiments revealed that NF-κB p65 subunit is recruited to the apoE promoter following Hcy treatment of cells.CONCLUSION: Hcy-induced stress negatively modulates apoE expression via MEK1/2 and NF-κB activation. The decreased apo E expression in peripheral tissues may aggravate atherosclerosis, neurodegenerative diseases and renal dysfunctions.

APOLIPOPROTEIN E GENE POLYMORPHISMS AND RISK FOR CORONARY ARTERY DISEASE IN CHINESE XINJIANGUYGUR AND HAN POPULATION

Objective To examine the relationship between apolipoprotein E (Apo E) gene polymorphism and risk of coronary artery disease (CAD), analyzing association of polymorphism with classical risk factors. Methods A total of 124 patients (including 84 Han population and 40 Uygur population) with angiographically verified CAD or myocardial infarction were prospectively evaluated. Data referring to hypertension, diabetes, and tobacco consump-tion were recorded. The levels of total cholesterol (TC), high density lipoprotein (HDL) cholesterol, Apo A1 and B, and triglycerides (TG) were determined. DNA was obtained from 124 patients and 70 controls. In order to determine Apo E genotypes, DNA was PCR amplified and digested with HhaI. The genetic polymorphism of Apo E is due to three common alleles, epsilon(ε) 2, ε3, ε4, at a single autosomal gene locus. These alleles determine the six phenotypes E2/2, E3/3, E4/4, E4/2, E4/3, and E3/2. Results In Uygur population, the frequency of the ε2, ε3, and ε4 was 0.155, 0.648, and 0.197 respectively. In Han po-pulation, the frequency of the ε2, ε3, and ε4 was 0.081, 0.772, and 0.146 respectively. In the patient group, the frequency of the ε2, ε3, and ε4was 0.060, 0.758, and 0.182 respectively. In the control group, the frequency of the ε2, ε3, and ε4 was 0.193, 0.671, and 0.136 respectively. ε2 frequency of Uygur’ patients and controls was 0.050 and 0.290 respectively. Serum low density lipoprotein (LDL) cholesterol, TC, and TG values tended to decrease from the Apo E-4 phenotypes to Apo E-2 phenotypes. When deletion polymorphism of ε2 was compared with the common risk factors for CAD, its risk ratio (RR) is 4.38. Conclusions These studies confirm and find that Apo E phenotype distribution in Uygur population differs significantly from that in Han population in Xinjiang. CAD patients have significantly lower ε2 allele and slightly higher ε3 or ε4 allele frequency than controls, especially in Uygur population. It shows protective effects of ε2 on CAD.

Apolipoprotein B100 quality control and the regulation of hepatic very low density lipoprotein secretion

Apolipoprotein B （apoB） is the main protein component of very low density lipoprotein （VLDL） and is necessary for the assembly and secretion of these triglyceride （TG）-rich particles. Following release from the liver, VLDL is converted to low density lipoprotein （LDL） in the plasma and increased production of VLDL can therefore play a detrimental role in cardiovascular disease. Increasing evidence has helped to establish VLDL assembly as a target for the treatment of dyslipidemias. Multiple factors are involved in the folding of the apoB protein and the formation of a secretion-competent VLDL particle. Failed VLDL assembly can initiate quality control mechanisms in the hepatocyte that target apoB for degradation. ApoB is a substrate for endoplasmic reticulum associated degradation （ERAD） by the ubiquitin proteasome system and for autophagy. Efficient targeting and disposal of apoB is a regu- lated process that modulates VLDL secretion and partitioning of TG. Emerging evidence suggests that significant overlap exists between these degradative pathways. For example, the insulin-mediated targeting of apoB to autop- hagy and postprandial activation of the unfolded protein response （UPR） may employ the same cellular machinery and regulatory cues. Changes in the quality control mechanisms for apoB impact hepatic physiology and pathology states, including insulin resistance and fatty liver. Insulin signaling, lipid metabolism and the hepatic UPR may impact VLDL production, particularly during the postprandial state. In this review we summarize our current understanding of VLDL assembly, apoB degradation, quality control mechanisms and the role of these processes in liver physiology and in pathologic states.