E4 Isoform Research Articles

Development of Apolipoprotein E–Deficient Mice

The first mouse carrying a deletion mutation in its apolipoprotein E (apoE) gene was born in our mouse colony in the summer of 1991. Our ongoing experiments to that point had indicated that this would happen, but the realization that the mouse in front of my eyes had inherited a mutation that we had designed and made in the laboratory filled me with awe. It did not occur to me immediately that this mouse would develop hypercholesterolemia and atherosclerosis and dictate the direction of my research for the next 20 years. I here briefly describe the background and my personal experience that led to the development of apoE-deficient mice as a model for human atherosclerosis. As a research scientist in the Department of Genetics at the University of Wisconsin, my main interest during the early 1980s was directed toward understanding how different types of DNA recombination contribute to the architecture and diversity of individual genomes within human populations and to DNA differences between humans and nonhuman primates. My studies clearly showed that new alleles and new genes are constantly being formed in the human genome by recombinational events, particularly between existing members of multigene families. There also appeared to be hot spots for recombination. By tracing a history of the human haptoglobin-gene cluster from the present-day structures in human populations and in other primates, I found that a single recombination event between related genes often produces much more drastic changes in the genome than those that result from simple point mutations.1 Whether this frequent yet natural occurrence of homologous recombination in the mammalian genome could be used to alter the genome of mammalian cells in culture in a preplanned fashion became a question of interest to several laboratories.2,3 An affirmative answer was first obtained in 1985, …

Apolipoprotein E isoform related clearance of amyloid-β by primary cortical astrocytes

Progressive accumulation of amyloid-ß (Aß) in the brain is the hallmark of Alzheimer's disease (AD). Excess Aß assembles into toxicoligomers or fibrils, which became deposited in the form of plaques or vascular deposits. As no compelling evidences for age related increase in Aß production have been provided, it is likely that impairment of Aß clearance plays critical role in development of sporadic AD. Multiple pathways of Aß clearance include proteolytic, enzymatic degradation in the extracellular space, clearance of Aß through the blood brain barrier, or uptake and degradation by glial cells. Indeed, astrocytes take up Aß in a clathrin-caveolin-dynamin-independent endocytosis through endosomes with efficiency depending on Aß aggregation status. Astrocytesare also the main source of apolipoprotein E (apo E) in the central nervous system. Apo E in isoform specific fashion is associated with the risk for AD occurrence. In this study we characterized uptake and degradation of Aß by astrocytes derived from apo E targeted replacement (TR) transgenic mice expressing human apo E isoforms E2, E3, and E4, apo E-KO mice, and wild type mice. Primary cortical astrocytes were established from 1-2 day old pups. Cells were treated with 1 to 10 μM of synthetic Aß40 or Aß42 for 0 to 96hr. The effect of Aß on astrocyte metabolic integrity was determined using MTT assay. The uptake of Aß from the medium and clearance by astrocyteswere evaluated using western-blotting analyses of cell culture medium and celllysate samples respectively. All tested astrocytes were capable of clearing Aß40 and Aß42 from the culture medium with stronger effect on Aß40. Analysis of lysates demonstrated a low accumulation of Aß40 inside astrocytes while significant amount of Aß42 was found inside all types of astrocytes, but less robust in apo E-KO. The intra-astrocytic accumulated Aß42 appears to be mainly oligomeric. MTT assay demonstrated that Aß42, but not Aß40, diminished metabolic activity of astrocytes. Astrocytes demonstrate great capacity of Aß uptake and degradation. The Aß uptake appears to be independent from of apo E isoformstatus. Excess of Aß42 oligomerizes and accumulates inside astrocytes resulting in their dysfunction as determined by MTT assays.

DNA Binding Restricts the Intrinsic Conformational Flexibility of Methyl CpG Binding Protein 2 (MeCP2)

Mass spectrometry-based hydrogen/deuterium exchange (H/DX) has been used to define the polypeptide backbone dynamics of full-length methyl CpG binding protein 2 (MeCP2) when free in solution and when bound to unmethylated and methylated DNA. Essentially the entire MeCP2 polypeptide chain underwent H/DX at rates faster than could be measured (i.e. complete exchange in ≤10 s), with the exception of the methyl DNA binding domain (MBD). Even the H/DX of the MBD was rapid compared with that of a typical globular protein. Thus, there is no single tertiary structure of MeCP2. Rather, the full-length protein rapidly samples many different conformations when free in solution. When MeCP2 binds to unmethylated DNA, H/DX is slowed several orders of magnitude throughout the MBD. Binding of MeCP2 to methylated DNA led to additional minor H/DX protection, and only locally within the N-terminal portion of the MBD. H/DX also was used to examine the structural dynamics of the isolated MBD carrying three frequent mutations associated with Rett syndrome. The effects of the mutations ranged from very little (R106W) to a substantial increase in conformational sampling (F155S). Our H/DX results have yielded fine resolution mapping of the structure of full-length MeCP2 in the absence and presence of DNA, provided a biochemical basis for understanding MeCP2 function in normal cells, and predicted potential approaches for the treatment of a subset of RTT cases caused by point mutations that destabilize the MBD.

Variations in apolipoprotein E frequency with age in a pooled analysis of a large group of older people.

Variation in the apolipoprotein E gene (APOE) has been reported to be associated with longevity in humans. The authors assessed the allelic distribution of APOE isoforms ε2, ε3, and ε4 among 10,623 participants from 15 case-control and cohort studies of age-related macular degeneration (AMD) in populations of European ancestry (study dates ranged from 1990 to 2009). The authors included only the 10,623 control subjects from these studies who were classified as having no evidence of AMD, since variation within the APOE gene has previously been associated with AMD. In an analysis stratified by study center, gender, and smoking status, there was a decreasing frequency of the APOE ε4 isoform with increasing age (χ(2) for trend = 14.9 (1 df); P = 0.0001), with a concomitant increase in the ε3 isoform (χ(2) for trend = 11.3 (1 df); P = 0.001). The association with age was strongest in ε4 homozygotes; the frequency of ε4 homozygosity decreased from 2.7% for participants aged 60 years or less to 0.8% for those over age 85 years, while the proportion of participants with the ε3/ε4 genotype decreased from 26.8% to 17.5% across the same age range. Gender had no significant effect on the isoform frequencies. This study provides strong support for an association of the APOE gene with human longevity.

Influence of liposome-mediated APOE3 gene transfection of brain tissue on diffuse axonal injury, caused by traumatic brain injury, in experiment

The goal of study was to estimate the structural damage of axons in rats with severe traumatic brain injury (TBI), and the possibilities of such disorders correction by means of gene therapy that launches the synthesis of e3 isoform of apolipoprotein E in brain tissue. Severe diffuse TBI in rats was inflicted under overall anesthesia by free load weighing 450 g, falling from a 1.5 m elevation. The mixture of DOTAP liposome and 25 µg of plasmid vector pCMV•SPORT6 with cDNA of APOE3 gene was infused intraventricularly using ALZET osmotic pumps. Severe experimental TBI is characterized by the damage of hippocampal cytoarchitectonics with destructive-dystrophic changes of all brain elements (neurons, glia, capillaries). The distinguishing feature of this damage is diffuse axonal injury exhibited by pronounced changes of axonal cytoskeleton, axonal edema and deformity, mitochondrial destruction and serious damage to myelin sheathes. The liposome-mediated brain tissue transfection with plasmid vector carrying the gene of e3 isoform of apolipoprotein E has a positive therapeutic effect after TBI including the decrease of diffuse axonal injury.

The ε3 and ε4 Alleles of Human APOE Differentially Affect Tau Phosphorylation in Hyperinsulinemic and Pioglitazone Treated Mice

BackgroundImpaired insulin signalling is increasingly thought to contribute to Alzheimer's disease (AD). The ε4 isoform of the APOE gene is the greatest genetic risk factor for sporadic, late onset AD, and is also associated with risk for type 2 diabetes mellitus (T2DM). Neuropathological studies reported the highest number of AD lesions in brain tissue of ε4 diabetic patients. However other studies assessing AD pathology amongst the diabetic population have produced conflicting reports and have failed to show an increase in AD-related pathology in diabetic brain. The thiazolidinediones (TZDs), peroxisome proliferator-activated receptor gamma agonists, are peripheral insulin sensitisers used to treat T2DM. The TZD, pioglitazone, improved memory and cognitive functions in mild to moderate AD patients. Since it is not yet clear how apoE isoforms influence the development of T2DM and its progression to AD, we investigated amyloid beta and tau pathology in APOE knockout mice, carrying human APOEε3 or ε4 transgenes after diet-induced insulin resistance with and without pioglitazone treatment.MethodsMale APOE knockout, APOEε3-transgenic and APOEε4-transgenic mice, together with background strain C57BL6 mice were kept on a high fat diet (HFD) or low fat diet (LFD) for 32 weeks, or were all fed HFD for 32 weeks and during the final 3 weeks animals were treated with pioglitazone or vehicle.ResultsAll HFD animals developed hyperglycaemia with elevated plasma insulin. Tau phosphorylation was reduced at 3 epitopes (Ser396, Ser202/Thr205 and Thr231) in all HFD, compared to LFD, animals independent of APOE genotype. The introduction of pioglitazone to HFD animals led to a significant reduction in tau phosphorylation at the Ser202/Thr205 epitope in APOEε3 animals only. We found no changes in APP processing however the levels of soluble amyloid beta 40 was reduced in APOE knockout animals treated with pioglitazone.

High ability of apolipoprotein E4 to stabilize amyloid‐β peptide oligomers, the pathological entities responsible for Alzheimer's disease

Nowadays, the emerging role of amyloid-β peptide (Aβ) oligomers in Alzheimer's disease (AD) is widely accepted, putting aside the old idea that fibrils are the primary entities responsible for the onset of the disease. Besides, carrying the E4 isoform of apolipoprotein E (apoE) represents the highest risk of developing AD. Nevertheless, the involvement of apoE4 in AD remains confusing. The goal of this study was to bring new insights into the role of apoE4 in Aβ aggregation. We used infrared spectroscopy, thioflavin T fluorescence, and Western blots to evaluate the influence of apoE isoforms on Aβ aggregation in vitro. Comparing Aβ controls with Aβ incubated either with the apoE3 or apoE4 isoform, we report a 30% reduction of the Aβ fibrillar content, whereas the oligomeric content is 2 times higher on incubation with the pathological isoform apoE4. ApoE4 would bind and block Aβ in its oligomeric conformation, inhibiting further formation of less toxic fibrillar forms of Aβ. While previous studies mostly correlated E4 with fibrils, our report underlines a link between apoE4 and Aβ oligomers and therefore reconciles apoE4 with the new amyloid cascade hypothesis. Our observations suggest that apoE4 strongly stabilizes Aβ oligomers, the pathological species responsible for Alzheimer's disease.

Apolipoprotein E, Alzheimer's Disease, and Amyloid: Do We Have the Cart Before the Horse?

The article by Thambisetty et al. [1] is notable in several ways. In part, it exemplifies the strengths of the current paradigm of biomarker technology, beginning with hypothesis-free discovery work, followed by independent validation, verification in multiple laboratories and, if appropriate, clinical application. Beyond this, however, the findings are provocative. They deviate from the usual sort of association between a biomarker and a disease entity—in this case, Alzheimer’s disease (AD). Instead, they probe the relationship of a plasma marker, apolipoprotein E (ApoE), and a widely accepted indicator of the disease process in its pre-symptomatic stages. More than 15 years ago, the work of Allen Roses, Judes Poirier, Margaret Pericak-Vance and others provided a powerful clue to the mystery of AD pathogenesis. This was, of course, the robust association—now demonstrated many times over—between AD and the 4 allele at the underlying genetic locus for apolipoprotein E, APOE. Many theories have subsequently been proposed to explain this association but in truth we have only a rudimentary understanding of it. To quote Churchill, the APOE-AD nexus remains “a riddle wrapped in a mystery inside an enigma”. Phylogenetic studies of ApoE show a near uniqueness of its E3 and E2 isoforms to humans. Evidently these two, especially the latter, do a better job of whatever is their critical function in support of the human brain than does the ancestral E4. The current paper’s findings appear to suggest, however, that ApoE concentration is important, as well as the protein isoform. Exactly how these two variables of concentration and isoform contribute to the overall function of ApoE is not yet clear. But now we have the question of why ApoE concentration (particularly that of E2 and E3) is positively correlated with amyloid burden. Most of us, certainly this observer, have assumed that ApoE concentration remains relatively constant over life. From that perspective, the present data would suggest that people with more ApoE would be those most vulnerable to fibrillar amyloid deposition. And this may be so, although I believe most would hardly have predicted it. But another perspective would hold that ApoE concentration is under dynamic control such that it increases longitudinally as people develop amyloid deposits, perhaps in response to these deposits, but also perhaps as a marker of some more fundamental process that gives rise to both amyloid and increased ApoE concentration. Arguments of this kind are familiar to those who are interested in biomarkers and surrogate indicators, but I do not believe they had ever been raised in connec-

Mapping ApoE/Aβ binding regions to guide inhibitor discovery

Blocking the interaction between the E4 isoform of apolipoprotein E (ApoE) and amyloid beta-peptide (Aβ) may be an avenue for pharmacological intervention in Alzheimer's disease (AD). The main regions of interaction of the two proteins are, respectively, ApoE244-272 and Aβ12-28. These protein segments are too large to facilitate the design of small molecule inhibitors. We mapped the primary components of ApoE/Aβ interaction to smaller peptide segments. Within the three motifs that are primarily responsible for ApoE/Aβ interaction, we identified four peptides that substantially block ApoE/Aβ interaction and further improved their inhibitory activity by rational hydrophobic amino acid substitution. Moreover, the mapping results provide the clue that the Aβ residues which interact with ApoE appear to be in the same region where Aβ self-interacts. According to this information, we found that Congo Red and X-34 could strongly inhibit ApoE/Aβ interaction. Our findings extend our understanding of ApoE/Aβ interaction and may guide the discovery of inhibitors that treat AD by antagonizing ApoE/Aβ interaction.

EST analysis on the gonad development related organs and microarray screen for differentially expressed genes in mature ovary and testis of Scylla paramamosain

A total of 5160 high quality ESTs (expressed sequence tags) averaging 357 bp were collected from normalized cDNA libraries created from testis, ovary and mixed organs of mud crab Scylla paramamosain. Clustering and assembly of these ESTs resulted in a total of 3837 unique sequences with 576 overlapping contigs and 3261 singletons. Comparisons with the GenBank non-redundant (Nr) protein database (BLASTx, e-values < 10 − 5 ) revealed putative functions or matched homologs from other organisms for 847 (22%) of the ESTs. Several gonad development related genes such as cathepsin C, thioredoxin peroxidase, vitellogenin receptor precursor, 50S ribosomal protein L24 and ubiquitin-conjugating enzyme E2 isoform 2 were identified from this EST project and demonstrated as gonad differential expression genes by rqRT-PCR. Sixty five different types of SSRs (simple sequence repeats) were identified from the total 411 EST-SSR motifs. A home-made cDNA microarray containing 5664 spots was developed and the hybridization results indicated that 39 unique transcripts were differentially expressed in testis and ovaries (P < 0.05). The expression levels of eleven unique transcripts examined by rqRT-PCR were matched with microarray fairly. These results will provide a useful resource for functional genomic studies on the biology of reproduction of mud crab.

A differential association of Apolipoprotein E isoforms with the amyloid‐β oligomer in solution

The molecular pathogenesis of disorders arising from protein misfolding and aggregation is difficult to elucidate, involving a complex ensemble of intermediates, whose toxicity depends upon their state of progression along distinct processing pathways. To address the complex misfolding and aggregation that initiates the toxic cascade resulting in Alzheimer's disease (AD), we have developed a 2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid spin-labeled amyloid-β (Aβ) peptide to observe its isoform-dependent interaction with the apoE protein. Although most individuals carry the E3 isoform of apoE, ∼15% of humans carry the E4 isoform, which is recognized as the most significant genetic determinant for Alzheimer's. ApoE is consistently associated with the amyloid plaque marker for AD. A vital question centers on the influence of the two predominant isoforms, E3 and E4, on Aβ peptide processing and hence Aβ toxicity. We used electron paramagnetic resonance (EPR) spectroscopy of incorporated spin labels to investigate the interaction of apoE with the toxic oligomeric species of Aβ in solution. EPR spectra of the spin-labeled side chain report on side chain and backbone dynamics as well as the spatial proximity of spins in an assembly. Our results indicate oligomer binding involves the C-terminal domain of apoE, with apoE3 reporting a much greater response through this conformational marker. Coupled with SPR binding measurements, apoE3 displays a higher affinity and capacity for the toxic Aβ oligomer. These findings support the hypothesis that apoE polymorphism and Alzheimer's risk can largely be attributed to the reduced ability of apoE4 to function as a clearance vehicle for the toxic form of Aβ.

Genetic connections between neurological disorders and cholesterol metabolism

Cholesterol is an essential component of both the peripheral and central nervous systems of mammals. Over the last decade, evidence has accumulated that disturbances in cholesterol metabolism are associated with the development of various neurological conditions. In addition to genetically defined defects in cholesterol synthesis, which will be covered in another review in this Thematic Series, defects in cholesterol metabolism (cerebrotendinous xanthomatosis) and intracellular transport (Niemann Pick Syndrome) lead to neurological disease. A subform of hereditary spastic paresis (type SPG5) and Huntington's disease are neurological diseases with mutations in genes that are of importance for cholesterol metabolism. Neurodegeneration is generally associated with disturbances in cholesterol metabolism, and presence of the E4 isoform of the cholesterol transporter apolipoprotein E as well as hypercholesterolemia are important risk factors for development of Alzheimer's disease. In the present review, we discuss the links between genetic disturbances in cholesterol metabolism and the above neurological disorders.

Disruption of ptLPD1 or ptLPD2, genes that encode isoforms of the plastidial lipoamide dehydrogenase, confers arsenate hypersensitivity in Arabidopsis.

Arsenic is a ubiquitous environmental poison that inhibits root elongation and seed germination to a variable extent depending on the plant species. To understand the molecular mechanisms of arsenic resistance, a genetic screen was developed to isolate arsenate overly sensitive (aos) mutants from an activation-tagged Arabidopsis (Arabidopsis thaliana) population. Three aos mutants were isolated, and the phenotype of each was demonstrated to be due to an identical disruption of plastidial LIPOAMIDE DEHYDROGENASE1 (ptLPD1), a gene that encodes one of the two E3 isoforms found in the plastidial pyruvate dehydrogenase complex. In the presence of arsenate, ptlpd1-1 plants exhibited reduced root and shoot growth and enhanced anthocyanin accumulation compared with wild-type plants. The ptlpd1-1 plants accumulated the same amount of arsenic as wild-type plants, indicating that the aos phenotype was not due to increased arsenate in the tissues but to an increase in the innate sensitivity to the poison. Interestingly, a ptlpd1-4 knockdown allele produced a partial aos phenotype. Two loss-of-function alleles of ptLPD2 in Arabidopsis also caused elevated arsenate sensitivity, but the sensitivity was less pronounced than for the ptlpd1 mutants. Moreover, both the ptlpd1 and ptlpd2 mutants were more sensitive to arsenite than wild-type plants, and the LPD activity in isolated chloroplasts from wild-type plants was sensitive to arsenite but not arsenate. These findings show that the ptLPD isoforms are critical in vivo determinants of arsenite-mediated arsenic sensitivity in Arabidopsis and possible strategic targets for increasing arsenic tolerance.

ATR-FTIR, a new tool to analyze the oligomeric content of Aβ samples in the presence of apolipoprotein e isoforms

Alzheimer's disease (AD) is a neurodegenerative disorder caused by the aggregation of the amyloid-beta peptide (Aβ), leading to amyloid plaques deposition in the brain. Although Aβ aggregation pathway still remains unclear, recent studies point out the enhanced toxicity of oligomers compared to fibrils. The E4 isoform of apolipoprotein E (ApoE) is the major risk factor in AD as people carrying one e4 allele have significantly higher chances to develop the disease. Nevertheless, this phenomenon is still poorly understood. Our group has shown that attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) could discriminate between Aβ42 oligomers and fibrils. Indeed, oligomers display anti-parallel β-sheet spectral components while fibrils are characterized by a parallel β-sheet organization. Using those spectral features to analyze the oligomeric content of our samples, we studied the influence of ApoE on Aβ42 aggregation. Our experiments demonstrated that ApoE3 increased the amount of Aβ42 oligomers in the sample. We can thus determine the proportion of Aβ oligomers in the presence of another compound in the sample. We plan to use ATR-FTIR to assess the effects of the other isoforms of ApoE on Aβ aggregation. Moreover, this could be extended to study the influence of other molecules or proteins on Aβ aggregation.

ATR–FTIR, a new tool to analyze the oligomeric content of Aβ samples in the presence of apolipoprotein E isoforms

Alzheimer̕s disease (AD) is a neurodegenerative disorder caused by the aggregation of the amyloid-beta peptide (Aβ), leading to amyloid plaques deposition in the brain. Although Aβaggregation pathway still remains unclear, recent studies point out the enhanced toxicity of oligomers compared to fibrils. The E4 isoform of apolipoprotein E (ApoE) is the major risk factor in AD as people carrying one ɛ4 allele have significantly higher chances to develop the disease. Nevertheless, this phenomenon is still poorly understood.Our group has shown that attenuated total reflection Fourier-transform infrared spectroscopy (ATR–FTIR) could discriminate between Aβ42 oligomers and fibrils. Indeed, oligomers display anti-parallel β-sheet spectral components while fibrils are characterized by a parallelβ-sheet organization. Using those spectral features to analyze the oligomeric content of our samples, we studied the influence of ApoE on Aβ42 aggregation. Our experiments demonstrated that ApoE3 increased the amount of Aβ42 oligomers in the sample.We can thus determine the proportion of Aβoligomers in the presence of another compound in the sample. We plan to use ATR–FTIR to assess the effects of the other isoforms of ApoE on Aβaggregation. Moreover, this could be extended to study the influence of other molecules or proteins on Aβaggregation.

Effects of hydrogen peroxide and apolipoprotein E isoforms on apolipoprotein E trafficking in HepG2 cells

1. The major source of apolipoprotein E (apoE) is the liver. In the present study, the effects of oxidative stress and apoE isoforms on apoE distribution and trafficking were established using the HepG2 liver tumour cell line. 2. Hydrogen peroxide (0, 25, 250 and 1000 micromol/L) was associated with rapid and concentration-dependent redistribution of apoE into the early endosomal compartment. This redistribution was achieved with a much lower concentration (25 micromol/L) than that needed to induce changes in intracellular apoE mRNA expression, apoE protein levels and markers of oxidative stress (250-1000 micromol/L). 3. Live cell imaging of apoE3-green fluorescent protein revealed a significant decrease in traffic velocity in response to oxidative stress. 4. The E4 isoform was associated with reduced trafficking velocity compared with the E3 isoform under basal conditions. 5. The results indicate that oxidative stress and apoE isoforms influence apoE trafficking and distribution within HepG2 cells. Altered apoE hepatocyte trafficking may provide a mechanistic link between oxidative stress, ageing and some diseases in older people.

Preventing cognitive decline in elderly demented/depressed patients and in ApoE4 mouse as a model of human Alzheimer's disease by feeding acetyl-l-carnitine and lipoic acid

The E4 isoform of apolipoprotein E (ApoE) is involved in cardiovascular and cerebrovascular disorders and is the most prevalent risk factor for late onset or sporadic AD. ApoE4 transgenic mice are appropriate models for studying the pathogenesis and preclinical treatment of ApoE-related cognitive deficits associated with late onset AD. This study uses the vascular dementia paradigm to analyze the effects of selective mitochondrial antioxidants, acetyl-Carnitine and R-Lipoic acid, and ApoE4 on CBF, neuropathology, brain and vessel ultrastructural abnormalities, and behavior in ApoE4 mice. We have also compared these results with our ongoing clinical study of clinically depressed demented seniors with cardiovascular diseases symptoms. The patients received Alpha-Lipoic Acid, Acetyl-L-Carnitine, Omega-3 and Coenzyme Q-10, along with diet changes, and our recently developed brain activation program. ApoE4 associated factors reduce cerebral blood flow (CBF) gradually to create brain hypoperfusion when compared to wild-type (WT) and the differences in CBF are greatest as animals age from 6-weeks to 12-months. Transmission electron microscopy (TEM) with colloidal gold immunocytochemistry and in situ hybridization using human and mouse DNA probes shows structural damage and mitochondrial DNA overproliferation and/or deletion in young and aged microvessel endothelium of ApoE4 animals, extending to the cytoplasm of perivascular cells, perivascular nerve terminals, hippocampal neurons, and glial cells. Spatial memory and temporal memory tests show a trend in improving cognitive function in ApoE4 mice fed selective mitochondrial antioxidants acetyl-L-Carnitine and R-Lipoic acid. Our clinical results show that patients who receive mitochondrial antioxidants present the maximum significant cognitive improvement at the end of 24 months of the treatment. Further examination of ultrastructural degeneration caused by aging, especially under cardiovascular diseases complication, will likely contribute to our understanding of neurodegenerative etiology and indicates a new avenue of development for novel prophylactic and treatment strategies by ensuing selective mitochondrial antioxidants for the demented patients.

Apolipoprotein E polymorphism interacts with cigarette smoking in progression of multiple sclerosis

The influence of apolipoprotein E (ApoE) polymorphism on clinical severity of multiple sclerosis (MS) is still controversial. Cigarette smoking has been suggested to influence the progression of disability in these patients. In this study, we aimed to investigate whether an interaction of smoking with the ApoE polymorphism influences the progression of disability in MS patients. Smoking history from 205 female patients with MS was obtained. Clinical data collected include age at onset, disease duration, annual relapse rate, the Expanded Disability Status Scale (EDSS) and the Multiple Sclerosis Severity Score (MSSS). ApoE polymorphism was examined in all patients and stratified according to smoking status and associations with the clinical data investigated. There were no significant associations between cigarette smoking and any of the clinical characteristics in the whole group of patients. In women carrying the ApoE E4 isoform, smokers had a lower EDSS (P = 0.033) and MSSS (P = 0.023) in comparison with non-smokers. Our data suggest that in women with MS carrying the ApoE E4 isoform, cigarette smoking may have a protective influence on disease progression and accumulation of disability. These findings need to be confirmed by future large longitudinal studies.

Genetic Variants Associated With Myocardial Infarction Risk Factors in Over 8000 Individuals From Five Ethnic Groups

Background— Myocardial infarction (MI) is a leading cause of death globally, but specific genetic variants that influence MI and MI risk factors have not been assessed on a global basis. Methods and Results— We included 8795 individuals of European, South Asian, Arab, Iranian, and Nepalese origin from the INTERHEART case-control study that genotyped 1536 single-nucleotide polymorphisms (SNPs) from 103 genes. One hundred and two SNPs were nominally associated with MI, but the statistical significance did not remain after adjustment for multiple testing. A subset of 940 SNPs from 69 genes were tested against MI risk factors. One hundred and sixty-three SNPs were nominally associated with a MI risk factor and 13 remained significant after adjusting for multiple testing. Of these 13, 11 were associated with apolipoprotein (Apo) B/A1 levels: 8 SNPs from 3 genes were associated with Apo B, and 3 cholesteryl ester transfer protein SNPs were associated with Apo A1. Seven of 8 of the SNPs associated with Apo B levels were nominally associated with MI ( P &lt;0.05), whereas none of the 3 cholesteryl ester transfer protein SNPs were associated with MI ( P ≥0.17). Of the 3 SNPs most significantly associated with MI, rs7412, which defines the Apo E2 isoform, was associated with both a lower Apo B/A1 ratio ( P =1.0�10 −7 ) and lower MI risk ( P =0.0004). Two low-density lipoprotein receptor variants, 1 intronic (rs6511720) and 1 in the 3′ untranslated region (rs1433099) were both associated with a lower Apo B/A1 ratio ( P &lt;1.0�10 −5 ) and a lower risk of MI ( P =0.004 and P =0.003, respectively). Conclusions— Thirteen common SNPs were associated with MI risk factors. Importantly, SNPs associated with Apo B levels were associated with MI, whereas SNPs associated with Apo A1 levels were not. The Apo E isoform, and 2 common low-density lipoprotein receptor variants (rs1433099 and rs6511720) influence MI risk in this multiethnic sample.

An altered pattern of circulating apolipoprotein E3 isoforms is implicated in preeclampsia

Preeclampsia is a common pregnancy complication that is an important cause of preterm birth and fetal growth restriction. Because there is no diagnostic test yet available for preeclampsia, we used a proteomic approach to identify novel serum/plasma biomarkers for this condition. We conducted case control studies comparing nulliparous women who developed preeclampsia at 36-38 weeks of gestation with healthy nulliparous women matched by gestational age at sampling. Serum/plasma was depleted of six abundant proteins and analyzed by two-dimensional gel electrophoresis (n = 12 per group) and difference gel electrophoresis (n = 12 per group). Differences in abundance of protein spots were detected by univariate and multivariate statistical analyses. Proteins were identified by mass spectrometry and expression of selected proteins was validated by immunoblotting. Proteins whose concentrations were selectively associated with preeclampsia included apolipoprotein E (apoE), apoC-II, complement factor C3c, fibrinogen, transthyretin, and complement factor H-related protein 2. An increase in a deglycosylated isoform of apoE3 and concomitantly decreased amounts of one apoE3 glycoisoform were identified in preeclamptic plasma and confirmed by immunoblotting. Altered production of these preeclampsia-related apoE3 isoforms might impair reverse cholesterol transport, contributing to arterial damage. These findings point to a novel mechanistic link between preeclampsia and subsequent cardiovascular disease.