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Lozupone M, Dibello V, Sardone R, Castellana F, Zupo R, Lampignano L, Bortone I, Daniele A, Bellomo A, Solfrizzi V, Panza F. The Impact of Apolipoprotein E ( APOE) Epigenetics on Aging and Sporadic Alzheimer's Disease. BIOLOGY 2023; 12:1529. [PMID: 38132357 PMCID: PMC10740847 DOI: 10.3390/biology12121529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
Sporadic Alzheimer's disease (AD) derives from an interplay among environmental factors and genetic variants, while epigenetic modifications have been expected to affect the onset and progression of its complex etiopathology. Carriers of one copy of the apolipoprotein E gene (APOE) ε4 allele have a 4-fold increased AD risk, while APOE ε4/ε4-carriers have a 12-fold increased risk of developing AD in comparison with the APOE ε3-carriers. The main longevity factor is the homozygous APOE ε3/ε3 genotype. In the present narrative review article, we summarized and described the role of APOE epigenetics in aging and AD pathophysiology. It is not fully understood how APOE variants may increase or decrease AD risk, but this gene may affect tau- and amyloid-mediated neurodegeneration directly or indirectly, also by affecting lipid metabolism and inflammation. For sporadic AD, epigenetic regulatory mechanisms may control and influence APOE expression in response to external insults. Diet, a major environmental factor, has been significantly associated with physical exercise, cognitive function, and the methylation level of several cytosine-phosphate-guanine (CpG) dinucleotide sites of APOE.
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Affiliation(s)
- Madia Lozupone
- Department of Translational Biomedicine and Neuroscience (DiBrain), University of Bari Aldo Moro, 70121 Bari, Italy;
| | - Vittorio Dibello
- Department of Orofacial Pain and Dysfunction, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands;
| | - Rodolfo Sardone
- Local Healthcare Authority of Taranto, 74121 Taranto, Italy;
| | - Fabio Castellana
- Department of Interdisciplinary Medicine, Clinica Medica e Geriatria “Cesare Frugoni”, University of Bari Aldo Moro, 70121 Bari, Italy; (F.C.); (R.Z.); (V.S.)
| | - Roberta Zupo
- Department of Interdisciplinary Medicine, Clinica Medica e Geriatria “Cesare Frugoni”, University of Bari Aldo Moro, 70121 Bari, Italy; (F.C.); (R.Z.); (V.S.)
| | - Luisa Lampignano
- Local Healthcare Authority of Bari, ASL Bari, 70132 Bari, Italy;
| | - Ilaria Bortone
- Department of Translational Biomedicine and Neuroscience (DiBrain), University of Bari Aldo Moro, 70121 Bari, Italy;
| | - Antonio Daniele
- Department of Neuroscience, Catholic University of Sacred Heart, 00168 Rome, Italy;
- Neurology Unit, IRCCS Fondazione Policlinico Universitario A. Gemelli, 00168 Rome, Italy
| | - Antonello Bellomo
- Psychiatric Unit, Department of Clinical & Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
| | - Vincenzo Solfrizzi
- Department of Interdisciplinary Medicine, Clinica Medica e Geriatria “Cesare Frugoni”, University of Bari Aldo Moro, 70121 Bari, Italy; (F.C.); (R.Z.); (V.S.)
| | - Francesco Panza
- Department of Interdisciplinary Medicine, Clinica Medica e Geriatria “Cesare Frugoni”, University of Bari Aldo Moro, 70121 Bari, Italy; (F.C.); (R.Z.); (V.S.)
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Shwani T, Zhang C, Owen LA, Shakoor A, Vitale AT, Lillvis JH, Barr JL, Cromwell P, Finley R, Husami N, Au E, Zavala RA, Graves EC, Zhang SX, Farkas MH, Ammar DA, Allison KM, Tawfik A, Sherva RM, Li M, Stambolian D, Kim IK, Farrer LA, DeAngelis MM. Patterns of Gene Expression, Splicing, and Allele-Specific Expression Vary among Macular Tissues and Clinical Stages of Age-Related Macular Degeneration. Cells 2023; 12:2668. [PMID: 38067097 PMCID: PMC10705168 DOI: 10.3390/cells12232668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/05/2023] [Accepted: 11/09/2023] [Indexed: 12/18/2023] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness, and elucidating its underlying disease mechanisms is vital to the development of appropriate therapeutics. We identified differentially expressed genes (DEGs) and differentially spliced genes (DSGs) across the clinical stages of AMD in disease-affected tissue, the macular retina pigment epithelium (RPE)/choroid and the macular neural retina within the same eye. We utilized 27 deeply phenotyped donor eyes (recovered within a 6 h postmortem interval time) from Caucasian donors (60-94 years) using a standardized published protocol. Significant findings were then validated in an independent set of well-characterized donor eyes (n = 85). There was limited overlap between DEGs and DSGs, suggesting distinct mechanisms at play in AMD pathophysiology. A greater number of previously reported AMD loci overlapped with DSGs compared to DEGs between disease states, and no DEG overlap with previously reported loci was found in the macular retina between disease states. Additionally, we explored allele-specific expression (ASE) in coding regions of previously reported AMD risk loci, uncovering a significant imbalance in C3 rs2230199 and CFH rs1061170 in the macular RPE/choroid for normal eyes and intermediate AMD (iAMD), and for CFH rs1061147 in the macular RPE/choroid for normal eyes and iAMD, and separately neovascular AMD (NEO). Only significant DEGs/DSGs from the macular RPE/choroid were found to overlap between disease states. STAT1, validated between the iAMD vs. normal comparison, and AGTPBP1, BBS5, CERKL, FGFBP2, KIFC3, RORα, and ZNF292, validated between the NEO vs. normal comparison, revealed an intricate regulatory network with transcription factors and miRNAs identifying potential upstream and downstream regulators. Findings regarding the complement genes C3 and CFH suggest that coding variants at these loci may influence AMD development via an imbalance of gene expression in a tissue-specific manner. Our study provides crucial insights into the multifaceted genomic underpinnings of AMD (i.e., tissue-specific gene expression changes, potential splice variation, and allelic imbalance), which may open new avenues for AMD diagnostics and therapies specific to iAMD and NEO.
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Affiliation(s)
- Treefa Shwani
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
| | - Charles Zhang
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Leah A. Owen
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA; (A.S.); (A.T.V.)
- Department of Population Health Sciences, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA
- Department of Obstetrics and Gynecology, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA
| | - Akbar Shakoor
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA; (A.S.); (A.T.V.)
| | - Albert T. Vitale
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA; (A.S.); (A.T.V.)
| | - John H. Lillvis
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Veterans Administration Western New York Healthcare System, Buffalo, NY 14212, USA
| | - Julie L. Barr
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
| | - Parker Cromwell
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Robert Finley
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Nadine Husami
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Elizabeth Au
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Rylee A. Zavala
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Elijah C. Graves
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
| | - Sarah X. Zhang
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
| | - Michael H. Farkas
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
- Veterans Administration Western New York Healthcare System, Buffalo, NY 14212, USA
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
| | - David A. Ammar
- Lion’s Eye Institute for Transplant & Research, Tampa, FL 33605, USA;
| | - Karen M. Allison
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA;
| | - Amany Tawfik
- Department of Foundational Medical Studies and Eye Research Center, Oakland University William Beaumont School of Medicine, Rochester, MI 48309, USA;
- Eye Research Institute, Oakland University, Rochester, MI 48309, USA
| | - Richard M. Sherva
- Department of Medicine (Biomedical Genetics), Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA; (R.M.S.); (L.A.F.)
| | - Mingyao Li
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Dwight Stambolian
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Ivana K. Kim
- Retina Service, Massachusetts Eye & Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA;
| | - Lindsay A. Farrer
- Department of Medicine (Biomedical Genetics), Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA; (R.M.S.); (L.A.F.)
| | - Margaret M. DeAngelis
- Department of Ophthalmology, Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA; (T.S.); (C.Z.); (L.A.O.); (J.H.L.); (J.L.B.); (P.C.); (R.F.); (N.H.); (E.A.); (R.A.Z.); (E.C.G.); (S.X.Z.); (M.H.F.)
- Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA; (A.S.); (A.T.V.)
- Department of Population Health Sciences, University of Utah School of Medicine, The University of Utah, Salt Lake City, UT 84132, USA
- Veterans Administration Western New York Healthcare System, Buffalo, NY 14212, USA
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
- Genetics, Genomics and Bioinformatics Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York, University at Buffalo, Buffalo, NY 14203, USA
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Giannisis A, Al-Grety A, Carlsson H, Howell JC, Hu WT, Kultima K, Nielsen HM. Plasma apolipoprotein E levels, isoform composition, and dimer profile in relation to plasma lipids in racially diverse patients with Alzheimer's disease and mild cognitive impairment. Alzheimers Res Ther 2023; 15:119. [PMID: 37400888 PMCID: PMC10316569 DOI: 10.1186/s13195-023-01262-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/14/2023] [Indexed: 07/05/2023]
Abstract
BACKGROUND The APOEε4-promoted risk of Alzheimer's disease (AD) is lower in Black/African-Americans (B/AAs), compared to non-Hispanic whites (NHWs). Previous studies reported lower plasma apolipoprotein E (apoE) levels in NHW APOEε4-carriers compared to non-carriers, and low plasma apoE levels were directly associated with an increased risk of AD and all dementia. We further showed that APOEε3/ε3 AD patients exhibited reduced plasma apoE dimers compared to corresponding control subjects. Whether plasma apoE levels and apoE dimer formation differ between races/ethnicities and therefore may help explain AD risk racial disparity remains to be elucidated. METHODS Using mass spectrometry, we determined total plasma apoE and apoE isoform levels in a cohort of B/AAs (n = 58) and NHWs (n = 67) including subjects with normal cognition (B/AA: n = 25, NHW: n = 28), mild cognitive impairment (MCI) (B/AA: n = 24, NHW: n = 24), or AD dementia (B/AA: n = 9, NHW: n = 15). Additionally, we used non-reducing western blot analysis to assess the distribution of plasma apoE into monomers/disulfide-linked dimers. Plasma total apoE, apoE isoform levels, and % apoE monomers/dimers were assessed for correlations with cognition, cerebrospinal fluid (CSF) AD biomarkers, sTREM2, neurofilament light protein (NfL), and plasma lipids. RESULTS Plasma apoE was predominantly monomeric in both racial groups and the monomer/dimer distribution was not affected by disease status, or correlated with CSF AD biomarkers, but associated with plasma lipids. Plasma total apoE levels were not related to disease status and only in the NHW subjects we observed lower plasma apoE levels in the APOEε4/ε4-carriers. Total plasma apoE levels were 13% higher in B/AA compared to NHW APOEε4/ε4 subjects and associated with plasma high-density lipoprotein (HDL) in NHW subjects but with low-density lipoprotein levels (LDL) in the B/AA subjects. Higher plasma apoE4 levels, exclusively in APOEε3/ε4 B/AA subjects, were linked to higher plasma total cholesterol and LDL levels. In the controls, NHWs and B/AAs exhibited opposite associations between plasma apoE and CSF t-tau. CONCLUSIONS The previously reported lower APOEε4-promoted risk of AD in B/AA subjects may be associated with differences in plasma apoE levels and lipoprotein association. Whether differences in plasma apoE levels between races/ethnicities result from altered APOEε4 expression or turnover, needs further elucidation.
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Affiliation(s)
- Andreas Giannisis
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius Väg 16B, 114 18, Stockholm, Sweden
| | - Asma Al-Grety
- Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden
| | - Henrik Carlsson
- Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden
| | | | - William T Hu
- Department of Neurology, Emory University, Atlanta, GA, USA
- Department of Neurology, Rutgers-Robert Wood Johnson Medical School, and Institute for Health, Health Care Policy, and Aging Research, New Brunswick, NJ, USA
| | - Kim Kultima
- Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden
| | - Henrietta M Nielsen
- Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius Väg 16B, 114 18, Stockholm, Sweden.
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Lefterov I, Fitz NF, Lu Y, Koldamova R. APOEε4 and risk of Alzheimer's disease - time to move forward. Front Neurosci 2023; 17:1195724. [PMID: 37274212 PMCID: PMC10235508 DOI: 10.3389/fnins.2023.1195724] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
The inheritance of Apolipoprotein E4 (APOEε4) brings the highest genetic risk of Alzheimer's disease (AD), arguably the highest genetic risk in human pathology. Since the discovery of the association, APOE protein isoforms have been at the center of tens of thousands of studies and reports. While, without a doubt, our knowledge about the normal physiological function of APOE isoforms in the brain has increased tremendously, the questions of how the inheritance of the APOEε4 allele translates into a risk of AD, and the risk is materialized, remain unanswered. Moreover, the knowledge about the risk associated with APOEε4 has not helped design a meaningful preventative or therapeutic strategy. Animal models with targeted replacement of Apoe have been generated and, thanks to the recent NIH/NIA/Alzheimer's disease Association initiative, are now freely available to AD researchers. While helpful in many aspects, none of the available models recapitulates normal physiological transcriptional regulation of the human APOE gene cluster. Changes in epigenetic regulation of APOE alleles in animal models in response to external insults have rarely been if ever, addressed. However, these animal models provide a useful tool to handle questions and investigate protein-protein interactions with proteins expressed by other recently discovered genes and gene variants considered genetic risk factors of AD, like Triggering Receptor expressed on Myeloid cells 2 (TREM2). In this review, we discuss genetic and epigenetic regulatory mechanisms controlling and influencing APOE expression and focus on interactions of APOE and TREM2 in the context of microglia and astrocytes' role in AD-like pathology in animal models.
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Giannisis A, Al-Grety A, Carlsson H, Patra K, Twohig D, Sando SB, Lauridsen C, Berge G, Grøntvedt GR, Bråthen G, White LR, Kultima K, Nielsen HM. Plasma apolipoprotein E levels in longitudinally followed patients with mild cognitive impairment and Alzheimer’s disease. Alzheimers Res Ther 2022; 14:115. [PMID: 36002891 PMCID: PMC9400269 DOI: 10.1186/s13195-022-01058-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/29/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Low levels of plasma apolipoprotein E (apoE) and presence of the APOE ε4 allele are associated with an increased risk of Alzheimer’s disease (AD). Although the increased risk of AD in APOE ε4-carriers is well-established, the protein levels have received limited attention.
Methods
We here report the total plasma apoE and apoE isoform levels at baseline from a longitudinally (24 months) followed cohort including controls (n = 39), patients with stable amnestic mild cognitive impairment during 24 months follow up (MCI-MCI, n = 30), patients with amnestic MCI (aMCI) that during follow-up were clinically diagnosed with AD with dementia (ADD) (MCI-ADD, n = 28), and patients with AD with dementia (ADD) at baseline (ADD, n = 28). We furthermore assessed associations between plasma apoE levels with cerebrospinal fluid (CSF) AD biomarkers and α-synuclein, as well as both CSF and plasma neurofilament light chain (NfL), YKL-40 and kallikrein 6.
Results
Irrespective of clinical diagnosis, the highest versus the lowest apoE levels were found in APOE ε2/ε3 versus APOE ε4/ε4 subjects, with the most prominent differences exhibited in females. Total plasma apoE levels were 32% and 21% higher in the controls versus MCI-ADD and ADD patients, respectively. Interestingly, MCI-ADD patients exhibited a 30% reduction in plasma apoE compared to MCI-MCI patients. This decrease appeared to be associated with brain amyloid-β (Aβ42) pathology regardless of disease status as assessed using the Amyloid, Tau, and Neurodegeneration (A/T/N) classification. In addition to the association between low plasma apoE and low levels of CSF Aβ42, lower apoE levels were also related to higher levels of CSF total tau (t-tau) and tau phosphorylated at Threonine 181 residue (p-tau) and NfL as well as a worse performance on the mini-mental-state-examination. In MCI-ADD patients, low levels of plasma apoE were associated with higher levels of CSF α-synuclein and kallikrein 6. No significant correlations between plasma apoE and the astrocytic inflammatory marker YKL40 were observed.
Conclusions
Our results demonstrate important associations between low plasma apoE levels, Aβ pathology, and progression from aMCI to a clinical ADD diagnosis.
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Ojo JO, Reed JM, Crynen G, Vallabhaneni P, Evans J, Shackleton B, Eisenbaum M, Ringland C, Edsell A, Mullan M, Crawford F, Bachmeier C. APOE genotype dependent molecular abnormalities in the cerebrovasculature of Alzheimer's disease and age-matched non-demented brains. Mol Brain 2021; 14:110. [PMID: 34238312 PMCID: PMC8268468 DOI: 10.1186/s13041-021-00803-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 06/04/2021] [Indexed: 12/14/2022] Open
Abstract
Cerebrovascular dysfunction is a hallmark feature of Alzheimer's disease (AD). One of the greatest risk factors for AD is the apolipoprotein E4 (E4) allele. The APOE4 genotype has been shown to negatively impact vascular amyloid clearance, however, its direct influence on the molecular integrity of the cerebrovasculature compared to other APOE variants (APOE2 and APOE3) has been largely unexplored. To address this, we employed a 10-plex tandem isobaric mass tag approach in combination with an ultra-high pressure liquid chromatography MS/MS (Q-Exactive) method, to interrogate unbiased proteomic changes in cerebrovessels from AD and healthy control brains with different APOE genotypes. We first interrogated changes between healthy control cases to identify underlying genotype specific effects in cerebrovessels. EIF2 signaling, regulation of eIF4 and 70S6K signaling and mTOR signaling were the top significantly altered pathways in E4/E4 compared to E3/E3 cases. Oxidative phosphorylation, EIF2 signaling and mitochondrial dysfunction were the top significant pathways in E2E2 vs E3/E3cases. We also identified AD-dependent changes and their interactions with APOE genotype and found the highest number of significant proteins from this interaction was observed in the E3/E4 (192) and E4/E4 (189) cases. As above, EIF2, mTOR signaling and eIF4 and 70S6K signaling were the top three significantly altered pathways in E4 allele carriers (i.e. E3/E4 and E4/E4 genotypes). Of all the cerebrovascular cell-type specific markers identified in our proteomic analyses, endothelial cell, astrocyte, and smooth muscle cell specific protein markers were significantly altered in E3/E4 cases, while endothelial cells and astrocyte specific protein markers were altered in E4/E4 cases. These proteomic changes provide novel insights into the longstanding link between APOE4 and cerebrovascular dysfunction, implicating a role for impaired autophagy, ER stress, and mitochondrial bioenergetics. These APOE4 dependent changes we identified could provide novel cerebrovascular targets for developing disease modifying strategies to mitigate the effects of APOE4 genotype on AD pathogenesis.
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Affiliation(s)
- Joseph O Ojo
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA. .,James A. Haley Veterans' Hospital, Tampa, FL, USA. .,The Open University, Milton Keynes, UK.
| | - Jon M Reed
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, CT, USA
| | - Gogce Crynen
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA
| | | | - James Evans
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA
| | - Benjamin Shackleton
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,The Open University, Milton Keynes, UK
| | - Maximillian Eisenbaum
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,The Open University, Milton Keynes, UK
| | - Charis Ringland
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,The Open University, Milton Keynes, UK
| | - Anastasia Edsell
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA
| | - Michael Mullan
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,The Open University, Milton Keynes, UK
| | - Fiona Crawford
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,James A. Haley Veterans' Hospital, Tampa, FL, USA.,The Open University, Milton Keynes, UK
| | - Corbin Bachmeier
- Department of Experimental Neuropathology, Roskamp Institute, Sarasota, FL, 34243, USA.,The Open University, Milton Keynes, UK.,Bay Pines VA Healthcare System, Bay Pines, FL, USA
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7
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Zhou X, Fu AK, Ip NY. APOE signaling in neurodegenerative diseases: an integrative approach targeting APOE coding and noncoding variants for disease intervention. Curr Opin Neurobiol 2021; 69:58-67. [PMID: 33647674 DOI: 10.1016/j.conb.2021.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/05/2021] [Accepted: 02/05/2021] [Indexed: 10/22/2022]
Abstract
APOE (apolipoprotein E) is a key regulator of lipid metabolism and a leading genetic risk factor for Alzheimer's disease. While APOE participates in multiple biological pathways, its roles in diseases are largely due to the mutant protein encoded by APOE-ε4. However, emerging evidence suggests that some noncoding Alzheimer's disease risk variants residing in APOE and its nearby regions exert APOE-ε4-independent risks and modify APOE gene expression. Moreover, intervention strategies targeting APOE are being explored. In this review, we summarize the literature on the genetic risks and roles of APOE in biological systems. Moreover, we propose an integrative approach to evaluate disease risk and tailor interventions to aid research on APOE-associated diseases.
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Affiliation(s)
- Xiaopu Zhou
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China; Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, 518057 Shenzhen, Guangdong, China
| | - Amy Ky Fu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China; Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, 518057 Shenzhen, Guangdong, China
| | - Nancy Y Ip
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China; Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China; Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, Hong Kong University of Science and Technology Shenzhen Research Institute, Shenzhen-Hong Kong Institute of Brain Science, 518057 Shenzhen, Guangdong, China.
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8
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Lee EG, Tulloch J, Chen S, Leong L, Saxton AD, Kraemer B, Darvas M, Keene CD, Shutes-David A, Todd K, Millard S, Yu CE. Redefining transcriptional regulation of the APOE gene and its association with Alzheimer's disease. PLoS One 2020; 15:e0227667. [PMID: 31978088 PMCID: PMC6980611 DOI: 10.1371/journal.pone.0227667] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/24/2019] [Indexed: 01/09/2023] Open
Abstract
The apolipoprotein E gene (APOE) is the strongest genetic risk factor for late-onset Alzheimer's disease (AD), yet the expression of APOE is not clearly understood. For example, it is unclear whether AD patients have elevated or decreased APOE expression or why the correlation levels of APOE RNA and the ApoE protein differ across studies. Likewise, APOE has a single CpG island (CGI) that overlaps with its 3'-exon, and this CGI's effect is unknown. We previously reported that the APOE CGI is highly methylated in human postmortem brain (PMB) and that this methylation is altered in AD frontal lobe. In this study, we comprehensively characterized APOE RNA transcripts and correlated levels of RNA expression with DNA methylation levels across the APOE CGI. We discovered the presence of APOE circular RNA (circRNA) and found that circRNA and full-length mRNA each constitute approximately one third of the total APOE RNA, with truncated mRNAs likely constituting some of the missing fraction. All APOE RNA species demonstrated significantly higher expression in AD frontal lobe than in control frontal lobe. Furthermore, we observed a negative correlation between the levels of total APOE RNA and DNA methylation at the APOE CGI in the frontal lobe. When stratified by disease status, this correlation was strengthened in controls but not in AD. Our findings suggest a possible modified mechanism of gene action for APOE in AD that involves not only the protein isoforms but also an epigenetically regulated transcriptional program driven by DNA methylation in the APOE CGI.
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Affiliation(s)
- Eun-Gyung Lee
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Jessica Tulloch
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Sunny Chen
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Lesley Leong
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Aleen D. Saxton
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Brian Kraemer
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
- Department of Medicine, University of Washington, Seattle, WA, United States of America
| | - Martin Darvas
- Department of Pathology, University of Washington, Seattle, WA, United States of America
| | - C. Dirk Keene
- Department of Pathology, University of Washington, Seattle, WA, United States of America
| | - Andrew Shutes-David
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Kaitlin Todd
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Steve Millard
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
| | - Chang-En Yu
- Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, United States of America
- Department of Medicine, University of Washington, Seattle, WA, United States of America
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9
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Belloy ME, Napolioni V, Greicius MD. A Quarter Century of APOE and Alzheimer's Disease: Progress to Date and the Path Forward. Neuron 2019; 101:820-838. [PMID: 30844401 DOI: 10.1016/j.neuron.2019.01.056] [Citation(s) in RCA: 304] [Impact Index Per Article: 60.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/08/2019] [Accepted: 01/27/2019] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is considered a polygenic disorder. This view is clouded, however, by lingering uncertainty over how to treat the quasi "monogenic" role of apolipoprotein E (APOE). The APOE4 allele is not only the strongest genetic risk factor for AD, it also affects risk for cardiovascular disease, stroke, and other neurodegenerative disorders. This review, based mostly on data from human studies, ranges across a variety of APOE-related pathologies, touching on evolutionary genetics and risk mitigation by ethnicity and sex. The authors also address one of the most fundamental question pertaining to APOE4 and AD: does APOE4 increase AD risk via a loss or gain of function? The answer will be of the utmost importance in guiding future research in AD.
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Affiliation(s)
- Michaël E Belloy
- Department of Neurology and Neurological Sciences, FIND Lab, Stanford University, Stanford, CA 94304, USA
| | - Valerio Napolioni
- Department of Neurology and Neurological Sciences, FIND Lab, Stanford University, Stanford, CA 94304, USA
| | - Michael D Greicius
- Department of Neurology and Neurological Sciences, FIND Lab, Stanford University, Stanford, CA 94304, USA.
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10
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Non-coding variability at the APOE locus contributes to the Alzheimer's risk. Nat Commun 2019; 10:3310. [PMID: 31346172 PMCID: PMC6658518 DOI: 10.1038/s41467-019-10945-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 06/10/2019] [Indexed: 12/30/2022] Open
Abstract
Alzheimer’s disease (AD) is a leading cause of mortality in the elderly. While the coding change of APOE-ε4 is a key risk factor for late-onset AD and has been believed to be the only risk factor in the APOE locus, it does not fully explain the risk effect conferred by the locus. Here, we report the identification of AD causal variants in PVRL2 and APOC1 regions in proximity to APOE and define common risk haplotypes independent of APOE-ε4 coding change. These risk haplotypes are associated with changes of AD-related endophenotypes including cognitive performance, and altered expression of APOE and its nearby genes in the human brain and blood. High-throughput genome-wide chromosome conformation capture analysis further supports the roles of these risk haplotypes in modulating chromatin states and gene expression in the brain. Our findings provide compelling evidence for additional risk factors in the APOE locus that contribute to AD pathogenesis. Several studies show that APOE-ε4 coding variants are associated with Alzheimer’s disease (AD) risk. Here, Zhou et al. perform fine-mapping of the APOE region and find AD risk haplotypes with non-coding variants in the PVRL2 and APOC1 regions that are associated with relevant endophenotypes.
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11
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Rao S, Ghani M, Guo Z, Deming Y, Wang K, Sims R, Mao C, Yao Y, Cruchaga C, Stephan DA, Rogaeva E. An APOE-independent cis-eSNP on chromosome 19q13.32 influences tau levels and late-onset Alzheimer's disease risk. Neurobiol Aging 2018; 66:178.e1-178.e8. [PMID: 29395286 DOI: 10.1016/j.neurobiolaging.2017.12.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/18/2017] [Accepted: 12/27/2017] [Indexed: 10/18/2022]
Abstract
Although multiple susceptibility loci for late-onset Alzheimer's disease (LOAD) have been identified, a large portion of the genetic risk for this disease remains unexplained. LOAD risk may be associated with single-nucleotide polymorphisms responsible for changes in gene expression (eSNPs). To detect eSNPs associated with LOAD, we integrated data from LOAD genome-wide association studies and expression quantitative trait loci using Sherlock (a Bayesian statistical method). We identified a cis-regulatory eSNP (rs2927438) located on chromosome 19q13.32, for which subsequent analyses confirmed the association with both LOAD risk and the expression level of several nearby genes. Importantly, rs2927438 may represent an APOE-independent LOAD eSNP according to the weak linkage disequilibrium of rs2927438 with the 2 polymorphisms (rs7412 and rs429358) defining the APOE-ε2, -ε3, and -ε4 alleles. Furthermore, rs2927438 does not influence chromatin interaction events at the APOE locus or cis-regulation of APOE expression. Further exploratory analysis revealed that rs2927438 is significantly associated with tau levels in the cerebrospinal fluid. Our findings suggest that rs2927438 may confer APOE-independent risk for LOAD.
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Affiliation(s)
- Shuquan Rao
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China.
| | - Mahdi Ghani
- Tanz Centre for Research in Neurodegenerative Diseases, and Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Zhiyun Guo
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Yuetiva Deming
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA
| | - Kesheng Wang
- Department of Biostatistics and Epidemiology, College of Public Health, East Tennessee State University, Johnson City, TN, USA
| | - Rebecca Sims
- Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Canquan Mao
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Yao Yao
- Department of Fundamental Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Carlos Cruchaga
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Dietrich A Stephan
- Department of Human Genetics, Graduate School of Public Health, Pittsburgh, PA, USA
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Diseases, and Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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12
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Keeney JTR, Ibrahimi S, Zhao L. Human ApoE Isoforms Differentially Modulate Glucose and Amyloid Metabolic Pathways in Female Brain: Evidence of the Mechanism of Neuroprotection by ApoE2 and Implications for Alzheimer's Disease Prevention and Early Intervention. J Alzheimers Dis 2016; 48:411-24. [PMID: 26402005 DOI: 10.3233/jad-150348] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Three major genetic isoforms of apolipoprotein E (ApoE), ApoE2, ApoE3, and ApoE4, exist in humans and lead to differences in susceptibility to Alzheimer's disease (AD). This study investigated the impact of human ApoE isoforms on brain metabolic pathways involved in glucose utilization and amyloid-β (Aβ) degradation, two major areas that are significantly perturbed in preclinical AD. Hippocampal RNA samples from middle-aged female mice with targeted human ApoE2, ApoE3, and ApoE4 gene replacement were comparatively analyzed with a qRT-PCR custom array for the expression of 85 genes involved in insulin/insulin-like growth factor (Igf) signaling. Consistent with its protective role against AD, ApoE2 brain exhibited the most metabolically robust profile among the three ApoE genotypes. When compared to ApoE2 brain, both ApoE3 and ApoE4 brains exhibited markedly reduced levels of Igf1, insulin receptor substrates (Irs), and facilitated glucose transporter 4 (Glut4), indicating reduced glucose uptake. Additionally, ApoE4 brain exhibited significantly decreased Pparg and insulin-degrading enzyme (Ide), indicating further compromised glucose metabolism and Aβ dysregulation associated with ApoE4. Protein analysis showed significantly decreased Igf1, Irs, and Glut4 in ApoE3 brain, and Igf1, Irs, Glut4, Pparg, and Ide in ApoE4 brain compared to ApoE2 brain. These data provide the first documented evidence that human ApoE isoforms differentially affect brain insulin/Igf signaling and downstream glucose and amyloid metabolic pathways, illustrating a potential mechanism for their differential risk in AD. A therapeutic strategy that enhances brain insulin/Igf1 signaling activity to a more robust ApoE2-like phenotype favoring both energy production and amyloid homeostasis holds promise for AD prevention and early intervention.
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Affiliation(s)
| | - Shaher Ibrahimi
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA
| | - Liqin Zhao
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, KS, USA.,Neuroscience Graduate Program, University of Kansas, Lawrence, KS, USA
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13
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Ma Y, Smith CE, Lai C, Irvin MR, Parnell LD, Lee Y, Pham L, Aslibekyan S, Claas SA, Tsai MY, Borecki IB, Kabagambe EK, Berciano S, Ordovás JM, Absher DM, Arnett DK. Genetic variants modify the effect of age on APOE methylation in the Genetics of Lipid Lowering Drugs and Diet Network study. Aging Cell 2015; 14:49-59. [PMID: 25476875 PMCID: PMC4324456 DOI: 10.1111/acel.12293] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2014] [Indexed: 11/28/2022] Open
Abstract
Although apolipoprotein E (APOE) variants are associated with age-related diseases, the underlying mechanism is unknown and DNA methylation may be a potential one. With methylation data, measured by the Infinium Human Methylation 450 array, from 993 participants (age ranging from 18 to 87 years) in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study, and from Encyclopedia of DNA Elements (ENCODE) consortium, combined with published methylation datasets, we described the methylation pattern of 13 CpG sites within APOE locus, their correlations with gene expression across cell types, and their relationships with age, plasma lipids, and sequence variants. Based on methylation levels and the genetic regions, we categorized the 13 APOE CpG sites into three groups: Group 1 showed hypermethylation (> 50%) and were located in the promoter region, Group 2 exhibited hypomethylation (< 50%) and were located in the first two exons and introns, and Group 3 showed hypermethylation (> 50%) and were located in the exon 4. APOE methylation was negatively correlated with gene expression (minimum r = -0.66, P = 0.004). APOE methylation was significantly associated with age (minimum P = 2.06E-08) and plasma total cholesterol (minimum P = 3.53E-03). Finally, APOE methylation patterns differed across APOE ε variants (minimum P = 3.51E-05) and the promoter variant rs405509 (minimum P = 0.01), which further showed a significant interaction with age (P = 0.03). These findings suggest that methylation may be a potential mechanistic explanation for APOE functions related to aging and call for further molecular mechanistic studies.
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Affiliation(s)
- Yiyi Ma
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
| | - Caren E. Smith
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
| | - Chao‐Qiang Lai
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
| | - Marguerite R. Irvin
- Department of Epidemiology University of Alabama at Birmingham Birmingham AL USA
| | - Laurence D. Parnell
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
| | - Yu‐Chi Lee
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
| | - Lucia Pham
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
| | - Stella Aslibekyan
- Department of Epidemiology University of Alabama at Birmingham Birmingham AL USA
| | - Steven A. Claas
- Department of Epidemiology University of Alabama at Birmingham Birmingham AL USA
| | - Michael Y. Tsai
- Department of Laboratory Medicine and Pathology University of Minnesota Minneapolis MN USA
| | - Ingrid B. Borecki
- Department of Genetics Washington University School of Medicine St. Louis MO USA
| | | | - Silvia Berciano
- Instituto Madrileño de Estudios Avanzados en Alimentación (IMDEA‐FOOD) Madrid Spain
| | - José M. Ordovás
- Nutrition and Genomics Laboratory Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University Boston MA USA
- Instituto Madrileño de Estudios Avanzados en Alimentación (IMDEA‐FOOD) Madrid Spain
- Department of Epidemiology Centro Nacional Investigaciones Cardiovasculares (CNIC) Madrid Spain
| | | | - Donna K. Arnett
- Department of Epidemiology University of Alabama at Birmingham Birmingham AL USA
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14
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Salem N, Vandal M, Calon F. The benefit of docosahexaenoic acid for the adult brain in aging and dementia. Prostaglandins Leukot Essent Fatty Acids 2015; 92:15-22. [PMID: 25457546 DOI: 10.1016/j.plefa.2014.10.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 10/08/2014] [Indexed: 01/08/2023]
Abstract
A brief overview of the evidence for omega-3 fatty acids and, in particular, of docosahexaenoic acid (DHA), involvement in cognition and in dementia is given. Two studies are presented in this regard in which the key intervention is a DHA supplement. The fist, the MIDAS Study demonstrated that DHA can be of benefit for episodic memory in healthy adults with a mild memory complaint. The second, the ADCS AD trial found no benefit of DHA in the primary outcomes but found an intriguing benefit for cognitive score in ApoE4 negative allele patients. This leads to a consideration of the mechanisms of action and role of ApoE and its modulation by DHA. Given the fundamental role of ApoE in cellular lipid transport and metabolism in the brain and periphery, it is no surprise that ApoE affects n-3 PUFA brain function as well. It remains to be seen to what extent ApoE4 deleterious effect in AD is associated with n-3 PUFA-related cellular mechanisms in the brain and, more specifically, whether ApoE4 directly impairs the transport of DHA into the brain, as has been suggested.
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Affiliation(s)
- Norman Salem
- Nutritional Lipids, DSM Nutritional Products, Columbia, MD, USA.
| | - Milene Vandal
- Center de recherche du center Hospitalier de l׳Université Laval (CHUL), Québec, QC, Canada; Faculté de pharmacie, Université Laval, Quebec, Canada; Institut des Nutraceutiques et des Aliments Fonctionnels, Universite Laval, Quebec, Canada
| | - Frederic Calon
- Center de recherche du center Hospitalier de l׳Université Laval (CHUL), Québec, QC, Canada; Faculté de pharmacie, Université Laval, Quebec, Canada; Institut des Nutraceutiques et des Aliments Fonctionnels, Universite Laval, Quebec, Canada
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15
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Abstract
The vast majority of Alzheimer's disease (AD) cases are late onset (LOAD), which is genetically complex with heritability estimates up to 80%. Apolipoprotein E (APOE) has been irrefutably recognized as the major genetic risk factor, with semidominant inheritance, for LOAD. Although the mechanisms that underlie the pathogenic nature of APOE in AD are still not completely understood, emerging data suggest that APOE contributes to AD pathogenesis through both amyloid-β (Aβ)-dependent and Aβ-independent pathways. Given the central role for APOE in the modulation of AD pathogenesis, many therapeutic strategies have emerged, including converting APOE conformation, regulating APOE expression, mimicking APOE peptides, blocking the APOE/Aβ interaction, modulating APOE lipidation state, and gene therapy. Accumulating evidence also suggests the utility of APOE genotyping in AD diagnosis, risk assessment, prevention, and treatment response.
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Affiliation(s)
- Jin-Tai Yu
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China; ,
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16
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Wang J, Yu JT, Tan MS, Jiang T, Tan L. Epigenetic mechanisms in Alzheimer's disease: implications for pathogenesis and therapy. Ageing Res Rev 2013; 12:1024-41. [PMID: 23688931 DOI: 10.1016/j.arr.2013.05.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/08/2013] [Indexed: 12/14/2022]
Abstract
The vast majority of Alzheimer's disease (AD) are late-onset forms (LOAD) likely due to the interplay of environmental influences and individual genetic susceptibility. Epigenetic mechanisms, including DNA methylation, histone modifications and non-coding RNAs, constitute dynamic intracellular processes for translating environmental stimuli into modifications in gene expression. Over the past decade it has become increasingly clear that epigenetic mechanisms play a pivotal role in aging the pathogenesis of AD. Here, we provide a review of the major mechanisms for epigenetic modification and how they are reportedly altered in aging and AD. Moreover, we also consider how aberrant epigenetic modifications may lead to AD pathogenesis, and we review the therapeutic potential of epigenetic treatments for AD.
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Affiliation(s)
- Jun Wang
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, China
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17
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Reducing human apolipoprotein E levels attenuates age-dependent Aβ accumulation in mutant human amyloid precursor protein transgenic mice. J Neurosci 2012; 32:4803-11. [PMID: 22492035 DOI: 10.1523/jneurosci.0033-12.2012] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Apolipoprotein E4 (apoE4) plays a major role in the pathogenesis of Alzheimer's disease. Brain amyloid-β (Aβ) accumulation depends on age and apoE isoforms (apoE4 > apoE3) both in humans and in transgenic mouse models. Brain apoE levels are also isoform dependent, but in the opposite direction (apoE4 < apoE3). Thus, one prevailing hypothesis is to increase brain apoE expression to reduce Aβ levels. To test this hypothesis, we generated mutant human amyloid precursor protein transgenic mice expressing one or two copies of the human APOE3 or APOE4 gene that was knocked in and flanked by LoxP sites. We report that reducing apoE3 or apoE4 expression by 50% in 6-month-old mice results in efficient Aβ clearance and does not increase Aβ accumulation. However, 12-month-old mice with one copy of the human APOE gene had significantly reduced Aβ levels and plaque loads compared with mice with two copies, regardless of which human apoE isoform was expressed, suggesting a gene dose-dependent effect of apoE on Aβ accumulation in aged mice. Additionally, 12-month-old mice expressing one or two copies of the human APOE4 gene had significantly higher levels of Aβ accumulation and plaque loads than age-matched mice expressing one or two copies of the human APOE3 gene, suggesting an isoform-dependent effect of apoE on Aβ accumulation in aged mice. Moreover, Cre-mediated APOE4 gene excision in hippocampal astrocytes significantly reduced insoluble Aβ in adult mice. Thus, reducing, rather than increasing, apoE expression is an attractive approach to lowering brain Aβ levels.
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18
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Guerreiro RJ, Gustafson DR, Hardy J. The genetic architecture of Alzheimer's disease: beyond APP, PSENs and APOE. Neurobiol Aging 2012; 33:437-56. [PMID: 20594621 PMCID: PMC2980860 DOI: 10.1016/j.neurobiolaging.2010.03.025] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 03/01/2010] [Accepted: 03/11/2010] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a complex disorder with a clear genetic component. Three genes have been identified as the cause of early onset familial AD (EOAD). The most common form of the disease, late onset Alzheimer's disease (LOAD), is, however, a sporadic one presenting itself in later stages of life. The genetic component of this late onset form of AD has been the target of a large number of studies, because only one genetic risk factor (APOE4) has been consistently associated with the disease. However, technological advances allow new approaches in the study of complex disorders. In this review, we discuss the new results produced by genome wide association studies, in light of the current knowledge of the complexity of AD genetics.
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Affiliation(s)
- Rita J Guerreiro
- Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA.
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19
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Liu L, Aboud O, Jones RA, Mrak RE, Griffin WST, Barger SW. Apolipoprotein E expression is elevated by interleukin 1 and other interleukin 1-induced factors. J Neuroinflammation 2011; 8:175. [PMID: 22171672 PMCID: PMC3286434 DOI: 10.1186/1742-2094-8-175] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 12/15/2011] [Indexed: 01/14/2023] Open
Abstract
Background We have previously outlined functional interactions, including feedback cycles, between several of the gene products implicated in the pathogenesis of Alzheimer's disease. A number of Alzheimer-related stressors induce neuronal expression of apolipoprotein E (ApoE), β-amyloid precursor protein (βAPP), and fragments of the latter such as amyloid β-peptide (Aβ) and secreted APP (sAPP). These stressors include interleukin-1 (IL-1)-mediated neuroinflammation and glutamate-mediated excitotoxicity. Such circumstances are especially powerful when they transpire in the context of an APOE ε4 allele. Methods Semi-quantitative immunofluorescence imaging was used to analyze rat brains implanted with IL-1β slow-release pellets, sham pellets, or no pellets. Primary neuronal or NT2 cell cultures were treated with IL-1β, glutamate, Aβ, or sAPP; relative levels of ApoE mRNA and protein were measured by RT-PCR, qRT-PCR, and western immunoblot analysis. Cultures were also treated with inhibitors of multi-lineage kinases--in particular MAPK-p38 (SB203580), ERK (U0126), or JNK (SP600125)--prior to exposure of cultures to IL-1β, Aβ, sAPP, or glutamate. Results Immunofluorescence of tissue sections from pellet-implanted rats showed that IL-1β induces expression of βAPP, IL-1α, and ApoE; the latter was confirmed by western blot analysis. These protein changes were mirrored by increases in their mRNAs, as well as in those encoding IL-1β, IL-1β-converting enzyme (ICE), and tumor necrosis factor (TNF). IL-1β also increased ApoE expression in neuronal cultures. It stimulated release of sAPP and glutamate in these cultures too, and both of these agents--as well as Aβ--stimulated ApoE expression themselves, suggesting that they may contribute to the effect of IL-1β on ApoE levels. Inhibitors of MAPK-p38, ERK, and JNK inhibited ApoE induction by all these agents except glutamate, which was sensitive only to inhibitors of ERK and JNK. Conclusion Conditions of glial activation and hyperexcitation can elevate proinflammatory cytokines, ApoE, glutamate, βAPP, and its secreted fragments. Because each of these factors promotes glial activation and neuronal hyperexcitation, these relationships have the potential to sustain self-propagating neurodegenerative cycles that could culminate in a progressive neurodegenerative disorder such as Alzheimer's disease.
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Affiliation(s)
- Ling Liu
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Singleton A, Hardy J. A generalizable hypothesis for the genetic architecture of disease: pleomorphic risk loci. Hum Mol Genet 2011; 20:R158-62. [PMID: 21875901 DOI: 10.1093/hmg/ddr358] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The dominant and sometimes competing theories for the aetiology of complex human disease have been the common disease, common variant (CDCV) hypothesis, and the multiple rare variant (MRV) hypothesis. With the advent of genome wide association studies and of second-generation sequencing, we are fortunate in being able to test these ideas. The results to date suggest that these hypotheses are not mutually exclusive. Further, initial evidence suggests that both MRV and CDCV can be true at the same loci, and that other disease-related genetic mechanisms also exist at some of these loci. We propose calling these, pleomorphic risk loci, and discuss here how such loci not only offer understanding of the genetic basis of disease, but also provide mechanistic biological insight into disease processes.
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Affiliation(s)
- Andrew Singleton
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
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Cervantes S, Samaranch L, Vidal-Taboada JM, Lamet I, Bullido MJ, Frank-García A, Coria F, Lleó A, Clarimón J, Lorenzo E, Alonso E, Sánchez-Juan P, Rodríguez-Rodríguez E, Combarros O, Rosich M, Vilella E, Pastor P. Genetic variation in APOE cluster region and Alzheimer's disease risk. Neurobiol Aging 2011; 32:2107.e7-17. [PMID: 21752496 DOI: 10.1016/j.neurobiolaging.2011.05.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 05/10/2011] [Accepted: 05/30/2011] [Indexed: 11/29/2022]
Abstract
We report the fine mapping/sequencing results of promoter and regulatory regions of APOE cluster genes (APOE, APOC1, APOC4, APOC2, and TOMM40) in Alzheimer's disease (AD) risk as well as in the progression from mild cognitive impairment (MCI) to AD. Long-range sequencing in 29 MCI subjects who progressed to dementia revealed 7 novel variants. Two potentially relevant novel variants and 34 single nucleotide polymorphisms (SNPs) were genotyped in a large sample of AD, MCI, and control subjects (n = 1453). Globally, very little association signal was observed in our sample in the absence of APOE ε4. Rs5158 (APOC4 intron 1) and rs10413089 (3' to APOC2) showed a trend toward an increase in AD risk independently from APOE ε4 associated risk though it did not survive multiple test correction (uncorrected p = 0.0099 and 0.01, respectively). Interestingly, rs10413089 showed a similar effect in an independent series. The analysis of the discovery sample showed an association of TOMM40 single nucleotide polymorphisms with progression from MCI stage to AD (rs59007384 and rs11556510), as well as with a shorter time to progression from MCI status to AD (rs10119), though these results could not be replicated in independent series. Further studies are needed to investigate the role of APOE cluster variants in AD risk.
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Affiliation(s)
- Sebastián Cervantes
- Neurogenetics Laboratory, Division of Neurosciences, Center for Applied Medical Research, University of Navarra, Pamplona, Spain
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Association of ApoE and LRP mRNA levels with dementia and AD neuropathology. Neurobiol Aging 2011; 33:628.e1-628.e14. [PMID: 21676498 DOI: 10.1016/j.neurobiolaging.2011.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 03/21/2011] [Accepted: 04/29/2011] [Indexed: 11/21/2022]
Abstract
Inheritance of the ε4 allele of apolipoprotein E (ApoE) is the only confirmed and consistently replicated risk factor for late onset Alzheimer's disease (AD). ApoE is also a key ligand for low-density lipoprotein (LDL) receptor-related protein (LRP), a major neuronal low-density lipoprotein receptor. Despite the considerable converging evidence that implicates ApoE and LRP in the pathogenesis of AD, the precise mechanism by which ApoE and LRP modulate the risk for AD remains elusive. Moreover, studies investigating expression of ApoE and LRP in AD brain have reported variable and contradictory results. To overcome these inconsistencies, we studied the mRNA expression of ApoE and LRP in the postmortem brain of persons who died at different stages of dementia and AD-associated neuropathology relative to controls by quantitative polymerase chain reaction (qPCR) and Western blotting analyses. Clinical dementia rating scores were used as a measure of dementia severity, whereas, Braak neuropathological staging and neuritic plaque density were used as indexes of the neuropathological progression of AD. ApoE and LRP mRNA expression was significantly elevated in the postmortem inferior temporal gyrus (area 20) and the hippocampus from individuals with dementia compared with those with intact cognition. In addition to their strong association with the progression of cognitive dysfunction, LRP and ApoE mRNA levels were also positively correlated with increasing neuropathological hallmarks of AD. Additionally, Western blot analysis of ApoE protein expression in the hippocampus showed that the differential expression observed at the transcriptional level is also reflected at the protein level. Given the critical role played by LRP and ApoE in amyloid beta (Aβ) and cholesterol trafficking, increased expression of LRP and ApoE may not only disrupt cholesterol homeostasis but may also contribute to some of the neurobiological features of AD, including plaque deposition.
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Bekris LM, Galloway NM, Montine TJ, Schellenberg GD, Yu CE. APOE mRNA and protein expression in postmortem brain are modulated by an extended haplotype structure. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:409-417. [PMID: 19554612 PMCID: PMC2829359 DOI: 10.1002/ajmg.b.30993] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Currently the epsilon4 allele of the apolipoprotein E gene (APOE) is the strongest genetic risk factor for late onset Alzheimer's disease (AD). However, inheritance of the APOE epsilon4 allele is not necessary or sufficient for the development of AD. Genetic evidence suggests that multiple loci in a 70 kb region surrounding APOE are associated with AD risk. Even though these loci could represent surrogate markers in linkage disequilibrium with APOE epsilon4 allele, they could also contribute biological effects independent of the APOE epsilon4 allele. Our previous study identified multiple SNPs upstream from APOE that are associated with cerebrospinal fluid apoE levels, suggesting that a haplotype structure proximal to APOE can influence apoE expression. In this study, we examined apoE expression in human post-mortem brain (PMB), and constructed chromosome-phase-separated haplotypes of the APOE proximal region to evaluate their effect on PMB apoE expression. ApoE protein expression was found to differ among AD brain regions and to differ between AD and control hippocampus. In addition, an extended APOE proximal haplotype structure, spanning from the TOMM40 gene to the APOE promoter, may modulate apoE expression in a brain region-specific manner and may influence AD disease status. In conclusion, this haplotype-phenotype analysis of apoE expression in PMB suggests that either; (1) the cis-regulation of APOE expression levels extends far upstream of the APOE promoter or (2) an APOE epsilon4 allele independent mechanism involving the TOMM40 gene plays a role in the risk of AD.
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Affiliation(s)
- Lynn M. Bekris
- Geriatric Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington,Department of Medicine, University of Washington, Seattle, Washington
| | - Nichole M. Galloway
- Geriatric Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
| | - Thomas J. Montine
- Department of Pathology, University of Washington, Seattle, Washington
| | - Gerard D. Schellenberg
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chang-En Yu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington,Department of Medicine, University of Washington, Seattle, Washington
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Abstract
Surprisingly, whole genome analyses of complex human neurological and psychiatric disorders have revealed that many genetic risk factors are likely to influence gene expression rather than alter protein sequences. Previous analyses of neurological diseases have shown that genetic variability in gene expression levels of deposited proteins influence disease risk. With this background, we have embarked on a comprehensive project to determine the effects of common genetic variability on whole genome gene expression.
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Kim J, Basak JM, Holtzman DM. The role of apolipoprotein E in Alzheimer's disease. Neuron 2009; 63:287-303. [PMID: 19679070 PMCID: PMC3044446 DOI: 10.1016/j.neuron.2009.06.026] [Citation(s) in RCA: 1051] [Impact Index Per Article: 70.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 06/22/2009] [Accepted: 06/25/2009] [Indexed: 01/17/2023]
Abstract
The epsilon4 allele of apolipoprotein E (APOE) is the major genetic risk factor for Alzheimer's disease (AD). Although there have been numerous studies attempting to elucidate the underlying mechanism for this increased risk, how apoE4 influences AD onset and progression has yet to be proven. However, prevailing evidence suggests that the differential effects of apoE isoforms on Abeta aggregation and clearance play the major role in AD pathogenesis. Other potential mechanisms, such as the differential modulation of neurotoxicity and tau phosphorylation by apoE isoforms as well as its role in synaptic plasticity and neuroinflammation, have not been ruled out. Inconsistent results among studies have made it difficult to define whether the APOE epsilon4 allele represents a gain of toxic function, a loss of neuroprotective function, or both. Therapeutic strategies based on apoE propose to reduce the toxic effects of apoE4 or to restore the physiological, protective functions of apoE.
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Affiliation(s)
- Jungsu Kim
- Department of Neurology, Developmental Biology, Hope Center for Neurological Disorders, Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
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26
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Blom ES, Holmans P, Arepalli S, Adighibe O, Hamshere ML, Gatz M, Pedersen NL, Bergem ALM, Owen MJ, Hollingworth P, Goate A, Williams J, Lannfelt L, Hardy J, Wavrant-De Vrièze F, Glaser A. Does APOE explain the linkage of Alzheimer's disease to chromosome 19q13? Am J Med Genet B Neuropsychiatr Genet 2008; 147B:778-83. [PMID: 18161859 PMCID: PMC2726752 DOI: 10.1002/ajmg.b.30681] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We have studied the impact of the apolipoprotein E gene (APOE) on the chromosome 19 linkage peak from an analysis of sib-pairs affected by Alzheimer's disease. We genotyped 417 affected sib-pairs (ASPs) collected in Sweden and Norway (SWE), the UK and the USA for 10 microsatellite markers on chromosome 19. The highest Zlr (3.28, chromosome-wide P-value 0.036) from the multipoint linkage analysis was located approximately 1 Mb from APOE, at marker D19S178. The linkage to chromosome 19 was well explained by APOE in the whole sample as well as in the UK and USA subsamples, as identity by descent (IBD) increased with the number of epsilon4 alleles in ASPs. There was a suggestion from the SWE subsample that linkage was higher than would be expected from APOE alone, although the test for this did not reach formal statistical significance. There was also a significant age at onset (aao) effect on linkage to chromosome 19q13 in the whole sample, which manifested itself as increased IBD sharing in relative pairs with lower mean aao. This effect was partially, although not completely, explained by APOE. The aao effect varied considerably between the different subsamples, with most of the effect coming from the UK sample. The other samples showed smaller effects in the same direction, but these were not significant.
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Affiliation(s)
- Elin S Blom
- Section of Molecular Geriatrics, Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden.
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Wang SC, Oelze B, Schumacher A. Age-specific epigenetic drift in late-onset Alzheimer's disease. PLoS One 2008; 3:e2698. [PMID: 18628954 PMCID: PMC2444024 DOI: 10.1371/journal.pone.0002698] [Citation(s) in RCA: 297] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Accepted: 06/13/2008] [Indexed: 11/18/2022] Open
Abstract
Despite an enormous research effort, most cases of late-onset Alzheimer's disease (LOAD) still remain unexplained and the current biomedical science is still a long way from the ultimate goal of revealing clear risk factors that can help in the diagnosis, prevention and treatment of the disease. Current theories about the development of LOAD hinge on the premise that Alzheimer's arises mainly from heritable causes. Yet, the complex, non-Mendelian disease etiology suggests that an epigenetic component could be involved. Using MALDI-TOF mass spectrometry in post-mortem brain samples and lymphocytes, we have performed an analysis of DNA methylation across 12 potential Alzheimer's susceptibility loci. In the LOAD brain samples we identified a notably age-specific epigenetic drift, supporting a potential role of epigenetic effects in the development of the disease. Additionally, we found that some genes that participate in amyloid-beta processing (PSEN1, APOE) and methylation homeostasis (MTHFR, DNMT1) show a significant interindividual epigenetic variability, which may contribute to LOAD predisposition. The APOE gene was found to be of bimodal structure, with a hypomethylated CpG-poor promoter and a fully methylated 3'-CpG-island, that contains the sequences for the epsilon4-haplotype, which is the only undisputed genetic risk factor for LOAD. Aberrant epigenetic control in this CpG-island may contribute to LOAD pathology. We propose that epigenetic drift is likely to be a substantial mechanism predisposing individuals to LOAD and contributing to the course of disease.
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Affiliation(s)
- Sun-Chong Wang
- Institute of Systems Biology and Bioinformatics, National Central University, Jhongli City, Taiwan
| | | | - Axel Schumacher
- Epigenetics Lab, Department of Medicine II, Klinikum rechts der Isar, Munich, Germany
- * E-mail:
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28
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Villalpando-Berumen JM, Mejia-Arango S, Aguilar-Salinas CA, Ordonez-Sanchez ML, Gutierrez-Robledo LM. Apolipoprotein E epsilon4, Alzheimer's disease, and cognitive performance in elderly Mexican Mestizos. J Am Geriatr Soc 2008; 56:677-82. [PMID: 18205760 DOI: 10.1111/j.1532-5415.2007.01606.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine the relationship between apolipoprotein E (APOE) epsilon4 and Alzheimer's disease (AD) in the Mexican Mestizo population, as well as its effects on the cognitive profile of AD and elderly Mestizos without dementia. DESIGN Cross-sectional analysis of a cohort study. SETTING Evaluations were conducted at the geriatrics clinic of an academic medical hospital in Mexico City. PARTICIPANTS Forty-nine elderly subjects with AD and 141 controls selected from a representative sample of Mexican Mestizos aged 65 to 96 who participated in the Prevalence Survey of Dementia in the Mexico City Elderly Population cohort. MEASUREMENTS All subjects underwent APOE genotypification and a comprehensive clinical and neuropsychological evaluation. RESULTS There were no significant differences in epsilon3 and epsilon4 frequencies between the subjects with and without AD and a tendency toward higher epsilon4 and lower epsilon3 allele frequencies in subjects aged 75 and older. No association was found between APOE epsilon4 and the presence of AD. The age-, sex-, and education-adjusted risk for AD associated with at least one epsilon4 allele was 1.01 (95% confidence interval=0.45-2.23). Performance on a long-term visual memory test was significantly worse in APOE epsilon4 carriers than in APOE epsilon3 carriers only in the group with AD. CONCLUSION APOE epsilon4 did not increase the risk for AD in this Mexican Mestizo elderly urban population sample, although the presence of this allele seems to modify its clinical expression.
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Abstract
OBJECTIVE To investigate associations of APOE, APOE promoter (G-219T), and tau protein exon 6 polymorphisms (47 and 53) and a history of self-reported concussion in college athletes. DESIGN Multi-center cross-sectional study. SETTING Male football and male and female soccer programs at the University of South Carolina, Jacksonville University, Benedict College, and the College of Charleston. PARTICIPANTS Active 18- to 30-year-old (n = 195) intercollegiate male football players and male and female soccer players during 2001 and 2002. ASSESSMENT OF RISK FACTORS Written questionnaires and blood or mouthwash samples for DNA for genotyping by RFLP/PCR. MAIN OUTCOME MEASUREMENT Self-reported history of concussions over the previous 8 years. RESULTS A statistically significant, nearly 3-fold increase in risk of a history of concussion for those with the APOE promoter G-219T TT genotype relative to the GG genotype (OR, 2.8; 95% CI, 1.1 to 6.9) adjusted for age, sport, school, and years in their primary sport, a finding that was stronger for Cantu grade 2 and 3 concussions. CONCLUSIONS These results suggest that college athletes with an APOE promoter G-219T TT genotype may be at increased risk for having a history of concussions, especially more severe concussions. Although there was some support for the possibility that the tau 53 polymorphism may be associated with increased risk of prior concussion (OR, 2.1; 95% CI, 0.3 to 14.5), there was no support for an association with APOE genotypes. The results of this cross-sectional study support the need for a prospective study of genetic factors, such as APOE promoter polymorphisms, and the incidence of and sequelae from concussions in college athletes.
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Myers AJ, Gibbs JR, Webster JA, Rohrer K, Zhao A, Marlowe L, Kaleem M, Leung D, Bryden L, Nath P, Zismann VL, Joshipura K, Huentelman MJ, Hu-Lince D, Coon KD, Craig DW, Pearson JV, Holmans P, Heward CB, Reiman EM, Stephan D, Hardy J. A survey of genetic human cortical gene expression. Nat Genet 2007; 39:1494-9. [PMID: 17982457 DOI: 10.1038/ng.2007.16] [Citation(s) in RCA: 390] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Accepted: 09/11/2007] [Indexed: 11/10/2022]
Abstract
It is widely assumed that genetic differences in gene expression underpin much of the difference among individuals and many of the quantitative traits of interest to geneticists. Despite this, there has been little work on genetic variability in human gene expression and almost none in the human brain, because tools for assessing this genetic variability have not been available. Now, with whole-genome SNP genotyping arrays and whole-transcriptome expression arrays, such experiments have become feasible. We have carried out whole-genome genotyping and expression analysis on a series of 193 neuropathologically normal human brain samples using the Affymetrix GeneChip Human Mapping 500K Array Set and Illumina HumanRefseq-8 Expression BeadChip platforms. Here we present data showing that 58% of the transcriptome is cortically expressed in at least 5% of our samples and that of these cortically expressed transcripts, 21% have expression profiles that correlate with their genotype. These genetic-expression effects should be useful in determining the underlying biology of associations with common diseases of the human brain and in guiding the analysis of the genomic regions involved in the control of normal gene expression.
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Affiliation(s)
- Amanda J Myers
- Laboratory of Neurogenetics, National Institute on Aging, Porter Neuroscience Building, National Institutes of Health Main Campus, Bethesda, Maryland 20892, USA.
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Mahfouz RAR, Sabbagh AS, Zahed LF, Mahfoud ZR, Kalmoni RF, Otrock ZK, Taher AT, Zaatari GS. Apolipoprotein E gene polymorphism and allele frequencies in the Lebanese population. Mol Biol Rep 2007; 33:145-9. [PMID: 16817024 DOI: 10.1007/s11033-006-6260-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2005] [Indexed: 10/24/2022]
Abstract
Apolipoprotein E (ApoE) genotypes were studied in order to determine the prevalence in the Lebanese population and compare it with other populations. DNA from 160 unrelated healthy donors from our HLA-bank was used. ApoE genotype was determined using the CardioVascular Disease (CVD) StripAssay (this assay is based on a Polymerase Chain Reaction-Reverse Hybridization technique). The prevalence of genotypes E3/3, E3/4, and E2/3 was found to be 69%, 26%, and 22%, respectively, and 0.6% for each of E2/4 and E4/4 genotypes. The Lebanese population tested showed similarities to earlier reported ApoE genotypic distributions (high E3 allele frequency) but also peculiar differences especially to some Arabic countries (total absence of E2 allele among Saudis) and other populations. This is the first report from Lebanon that will serve as a template for future investigations of the prevalence of ApoE alleles in association with various clinical entities.
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Affiliation(s)
- Rami A R Mahfouz
- Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Riad El Solh, 1107 2020, P.O Box 11-0236, Beirut, Lebanon.
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Bray NJ, O'Donovan MC. Investigating cis-acting regulatory variation using assays of relative allelic expression. Psychiatr Genet 2006; 16:173-7. [PMID: 16829785 DOI: 10.1097/01.ypg.0000218612.35139.84] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Assays of relative allelic expression offer a powerful means of exploring the influence of cis-acting regulatory variation. In this article, we provide a general assay protocol and discuss practical and theoretical considerations for the design and interpretation of relative allelic expression analysis.
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Affiliation(s)
- Nicholas J Bray
- Department of Psychological Medicine, School of Medicine, Cardiff University, Cardiff, UK.
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Abstract
Apolipoprotein E (apoE) genotypes were determined in 165 Saudis. The prevalence of genotype, E3/E3, E3/E4 and E4/E4 was found to be 71, 27 and 2% respectively. The E3/E3 was the most prevalent genotype among the Saudis followed by E3/E4. However, other genotypes E2/E2, E2/E3 and E2/E4 were absent showing the absence of E2 allele in the test population. The high frequencies of the E3 allele (0.845) and E3/E3 genotype (0.71) and absence of E2 allele in Saudis under study are similar to those reported earlier for Native Americans, Mexican-Americans, Mayans, Cayapa, Mazatecan Indians and Mexican Mestizos populations.
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Lambert JC, Mann D, Richard F, Tian J, Shi J, Thaker U, Merrot S, Harris J, Frigard B, Iwatsubo T, Lendon C, Amouyel P. Is there a relation between APOE expression and brain amyloid load in Alzheimer's disease? J Neurol Neurosurg Psychiatry 2005; 76:928-33. [PMID: 15965197 PMCID: PMC1739723 DOI: 10.1136/jnnp.2004.048983] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND It has been proposed that, independent of the epsilon4 allele, APOE promoter polymorphisms (-491 A/T and -219 G/T) may be risks factor for Alzheimer's disease by modulating APOE expression. OBJECTIVE To measure the level of APOE expression in Alzheimer's disease. METHODS Brains were obtained at necropsy from 114 patients with early and late onset sporadic Alzheimer's disease in Greater Manchester (UK) during years 1986 to 2001. Total RNA was extracted from 84 brains. Purified lymphocytes were obtained from fresh blood from 16 probable Alzheimer cases from Lille (France). APOE and beta-actin gene expression was determined by reverse transcriptase polymerase chain reaction in brain and lymphocytes. RESULTS An inverse correlation between APOE expression level and A beta loads was observed. As previously described and extended to 114 cases here, an association between the -219 TT genotype and a higher level of parenchymal A beta deposition was found, irrespective of APOE epsilon4 allele status. This effect was more pronounced in older individuals, whereas higher A beta load appeared more closely related to epsilon4 in the younger age group (cut off point at the median age at death (72.5 years)). The -219 TT genotype was associated with a decrease in APOE expression. There was a 60% decrease in APOE expression in lymphocytes from probable Alzheimer cases v controls (p = 0.01). CONCLUSIONS In the oldest individuals, reduced APOE expression, modulated in part by -219 G/T polymorphism, may influence risk and constitute a determinant A beta load in Alzheimer's disease.
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Affiliation(s)
- J-C Lambert
- Unité INSERM 508, Institut Pasteur de Lille, BP 245, 1 rue du professeur Calmette, 59019 Lille cédex, France.
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Morihara T, Teter B, Yang F, Lim GP, Boudinot S, Boudinot FD, Frautschy SA, Cole GM. Ibuprofen suppresses interleukin-1beta induction of pro-amyloidogenic alpha1-antichymotrypsin to ameliorate beta-amyloid (Abeta) pathology in Alzheimer's models. Neuropsychopharmacology 2005; 30:1111-20. [PMID: 15688088 DOI: 10.1038/sj.npp.1300668] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Epidemiological and basic research suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) should protect against the most common forms of Alzheimer's disease (AD). Ibuprofen reduces amyloid (Abeta) pathology in some transgenic models, but the precise mechanisms remain unclear. Although some reports show select NSAIDs inhibit amyloid production in vitro, the possibility that in vivo suppression of amyloid pathology occurs independent of Abeta production has not been ruled out. We show that ibuprofen reduced Abeta brain levels in rats from exogenously infused Abeta in the absence of altered Abeta production. To determine whether ibuprofen inhibits pro-amyloidogenic factors, APPsw (Tg2576) mice were treated with ibuprofen for 6 months, and expression levels of the Abeta and inflammation-related molecules alpha1 antichymotrypsin (ACT), apoE, BACE1, and peroxisome proliferator-activated receptor gamma) (PPARgamma) were measured. Among these, ACT, a factor whose overexpression accelerates amyloid pathology, was reduced by ibuprofen both in vivo and in vitro. IL-1beta, which was reduced in our animals by ibuprofen, induced mouse ACT in vitro. While some NSAIDs may inhibit Abeta42 production, these observations suggest that ibuprofen reduction of Abeta pathology may not be mediated by altered Abeta42 production. We present evidence supporting the hypothesis that ibuprofen-dependent amyloid reduction is mediated by inhibition of an alternate pathway (IL-1beta and its downstream target ACT).
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Affiliation(s)
- Takashi Morihara
- Greater Los Angeles VA Healthcare System, GRECC, Sepulveda, CA, USA
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36
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Sergeant N, Delacourte A, Buée L. Tau protein as a differential biomarker of tauopathies. Biochim Biophys Acta Mol Basis Dis 2005; 1739:179-97. [PMID: 15615637 DOI: 10.1016/j.bbadis.2004.06.020] [Citation(s) in RCA: 197] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Accepted: 06/16/2004] [Indexed: 01/01/2023]
Abstract
Microtubule-associated Tau proteins are the basic component of intraneuronal and glial inclusions observed in many neurological disorders, the so-called tauopathies. Many etiological factors, phosphorylation, splicing, and mutations, relate Tau proteins to neurodegeneration. Molecular analysis has revealed that hyperphosphorylation and abnormal phosphorylation might be one of the important events in the process leading to tau intracellular aggregation. Specific set of pathological tau proteins exhibiting a typical biochemical pattern, and a different regional and laminar distribution, could characterize five main classes of tauopathies. A direct correlation has been established between the regional brain distribution of tau pathology and clinical symptoms; for instance progressive involvement of neocortical areas is well correlated to the severity of dementia in Alzheimer's disease, overall suggesting that pathological tau proteins are reliable marker of the neurodegenerative process. Recent discovery of tau gene mutations in frontotemporal dementia with parkinsonism linked to chromosome 17 has reinforced the predominant role attributed to tau proteins in the pathogenesis of neurodegenerative disorders, and underlined the fact that distinct sets of tau isoforms expressed in different neuronal populations could lead to different pathologies. Overall, a better knowledge of the etiological factors responsible for the aggregation of tau proteins in brain diseases is essential for development of future differential diagnosis and therapeutic strategies. They would hopefully find their application against Alzheimer's disease but also in all neurological disorders for which a dysfunction of Tau biology has been identified.
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Bray NJ, Jehu L, Moskvina V, Buxbaum JD, Dracheva S, Haroutunian V, Williams J, Buckland PR, Owen MJ, O'Donovan MC. Allelic expression of APOE in human brain: effects of epsilon status and promoter haplotypes. Hum Mol Genet 2004; 13:2885-92. [PMID: 15385439 DOI: 10.1093/hmg/ddh299] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The epsilon4 haplotype of APOE is the only undisputed genetic risk factor for late-onset Alzheimer's disease (LOAD). It has been proposed that at least two other polymorphisms in the promoter of the APOE gene (-219G>T and -491A>T) might also contribute to disease susceptibility, and modulate the impact of structural changes in the ApoE protein, by altering its expression. In order to assess the extent of cis-acting influences on APOE expression in human brain, highly quantitative measures of allele discrimination were applied to cortical RNA from individuals heterozygous for the epsilon alleles. A small, but significant, increase in the expression of epsilon4 allele was observed relative to that of the epsilon3 and epsilon2 alleles (P<0.0001). Similar differences were observed in brain tissue from confirmed LOAD subjects, and between cortical regions BA10 (frontopolar) and BA20 (inferior temporal). Stratification of epsilon4/epsilon3 allelic expression ratios according to heterozygosity for the -219G>T promoter polymorphism revealed significantly lower relative expression of haplotypes containing the -219T allele (P=0.02). Our data indicate that, in human brain, most of the cis-acting variance in APOE expression is accounted for by the epsilon4 haplotype, but there are additional, small, cis-acting influences associated with promoter genotype.
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Affiliation(s)
- Nicholas J Bray
- Department of Psychological Medicine, School of Medicine, Cardiff University, Cardiff , UK
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38
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Ding C, Maier E, Roscher AA, Braun A, Cantor CR. Simultaneous quantitative and allele-specific expression analysis with real competitive PCR. BMC Genet 2004; 5:8. [PMID: 15128429 PMCID: PMC411033 DOI: 10.1186/1471-2156-5-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Accepted: 05/05/2004] [Indexed: 11/17/2022] Open
Abstract
Background For a diploid organism such as human, the two alleles of a particular gene can be expressed at different levels due to X chromosome inactivation, gene imprinting, different local promoter activity, or mRNA stability. Recently, imbalanced allelic expression was found to be common in human and can follow Mendelian inheritance. Here we present a method that employs real competitive PCR for allele-specific expression analysis. Results A transcribed mutation such as a single nucleotide polymorphism (SNP) is used as the marker for allele-specific expression analysis. A synthetic mutation created in the competitor is close to a natural mutation site in the cDNA sequence. PCR is used to amplify the two cDNA sequences from the two alleles and the competitor. A base extension reaction with a mixture of ddNTPs/dNTP is used to generate three oligonucleotides for the two cDNAs and the competitor. The three products are identified and their ratios are calculated based on their peak areas in the MALDI-TOF mass spectrum. Several examples are given to illustrate how allele-specific gene expression can be applied in different biological studies. Conclusions This technique can quantify the absolute expression level of each individual allele of a gene with high precision and throughput.
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Affiliation(s)
- Chunming Ding
- Bioinformatics Program and Center for Advanced Biotechnology, Boston University, Boston, MA 02215 USA
| | - Esther Maier
- Children's Hospital, University of Munich, Lindwurmstrasse 4, 80337 Munich, Germany
| | - Adelbert A Roscher
- Children's Hospital, University of Munich, Lindwurmstrasse 4, 80337 Munich, Germany
| | | | - Charles R Cantor
- Bioinformatics Program and Center for Advanced Biotechnology, Boston University, Boston, MA 02215 USA
- SEQUENOM, Inc., San Diego, CA 92121 USA
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Lambert JC, Coyle N, Lendon C. The allelic modulation of apolipoprotein E expression by oestrogen: potential relevance for Alzheimer's disease. J Med Genet 2004; 41:104-12. [PMID: 14757857 PMCID: PMC1735679 DOI: 10.1136/jmg.2003.005033] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The epsilon4 allele of the apolipoprotein E (APOE) gene is a major genetic risk factor for Alzheimer's disease but appears to be associated with greater risk in women than in men. Some studies suggest that the level of APOE may of its own modulate the risk for Alzheimer's disease. Sex differences and an apparent benefit of oestrogen therapy suggest a role for oestrogen. APOE expression is influenced by oestrogen and oestrogen therapy may not benefit women bearing an APOE epsilon4 allele. These findings suggest an interaction between oestrogen and APOE in the Alzheimer's disease process. AIM To explore the hypothesis that APOE expression is regulated by a genomic mechanism and is modified by the polymorphisms in APOE associated with risk for Alzheimer's disease. METHODS In vitro binding studies were undertaken between oestrogen receptors and fragments of the human APOE gene. APOE gene expression was studied to investigate a possible functional interaction. RESULTS APOE epsilon2/epsilon3/epsilon4 coding and -219 G/T promoter polymorphisms influenced binding to the oestrogen receptor and altered transcriptional activity in response to oestrogen. CONCLUSIONS An allele dependent modulation of oestrogen induced regulation of APOE might be involved in the increased risk for Alzheimer's disease in women bearing an epsilon4 allele.
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Affiliation(s)
- J-C Lambert
- Molecular Psychiatry, Division of Neuroscience, Queen Elizabeth Psychiatric Hospital, Birmingham, UK
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Al-Khedhairy AAA. Apolipoprotein E polymorphism as a predictor for cognitive decline and dementia in the Saudi general population over 65 years. Genet Mol Biol 2004. [DOI: 10.1590/s1415-47572004000300004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Moreno JA, López-Miranda J, Marín C, Gómez P, Pérez-Martínez P, Fuentes F, Fernández de la Puebla RA, Paniagua JA, Ordovas JM, Pérez-Jiménez F. The influence of the apolipoprotein E gene promoter (-219G/ T) polymorphism on postprandial lipoprotein metabolism in young normolipemic males. J Lipid Res 2003; 44:2059-64. [PMID: 12923233 DOI: 10.1194/jlr.m300124-jlr200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The apolipoprotein E (apoE) gene promoter (-219G/T) polymorphism has been associated with increased risk of myocardial infarction, premature coronary heart disease, and decreased plasma apoE concentrations. We examined whether the -219G/T polymorphism could modify the postprandial response of triacylglycerol-rich lipoproteins (TRLs). Fifty-one healthy apoE 3/3 male volunteers (14GG, 29GT, and 8TT) were given a vitamin A fat-loading test consisting of 1 g of fat/kg body weight and 60,000 IU of vitamin A per m2 of body surface area. Blood samples were taken at time 0 and every hour until the sixth hour, and every 2 hours and 30 minutes until the eleventh hour. Cholesterol, triacylglycerols (TGs), and apoE were determined in plasma; and cholesterol, TG, apoB-100, apoB-48, and retinyl palmitate (RP) were analyzed in lipoprotein fractions. Postprandial lipemia data revealed that subjects with the -219TT genotype had a higher postprandial response of large TRL-cholesterol (P < 0.03), large TRL-triacylglycerols (P < 0.001), large TRL-RP (P < 0.004), and small TRL-apoB-48 (P < 0.03) than carriers of the -219G allele. Moreover, the -219TT subjects had the lowest postprandial levels of serum apoE (P < 0.05). In conclusion, the -219G/T polymorphism may influence TRL metabolism during the postprandial period, thus prolonging postprandial lipemia in subjects with the TT genotype.
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Affiliation(s)
- Juan Antonio Moreno
- Lipids and Atherosclerosis Research Unit, Hospital Reina Sofía University, Córdoba, Spain
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Yang JD, Feng GY, Zhang J, Cheung J, St Clair D, He L, Ichimura K. Apolipoprotein E -491 promoter polymorphism is an independent risk factor for Alzheimer's disease in the Chinese population. Neurosci Lett 2003; 350:25-8. [PMID: 12962909 DOI: 10.1016/s0304-3940(03)00815-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Polymorphisms at positions -491, -427 and -219 in the promoter region of the Apolipoprotein E APOE gene have been variously reported to confer an increased risk of developing Alzheimer's disease (AD) independent of the effect of epsilon 2, 3 or 4 alleles in exon 4. In order to assess APOE promoter polymorphisms as independent risk factors in AD we have compared results in 183 definite or probable AD cases with 133 controls. We assayed markers at sites -491, -427, -219, and +113 in APOE gene and a polymorphic Hha1 site in the nearby APOC1 gene. We found that APOE promoter polymorphisms and APOC1 insertion alleles were significantly associated with AD. However, after stratification for epsilon 4 allele, only the A allele at -491 in APOE remained significantly associated with AD. The effects of the other markers depended almost entirely upon linkage disequilibrium with epsilon 4 allele, and only trends remained when cases and controls were stratified for the presence or absence of epsilon 4 allele. This occurred irrespective of whether markers were examined separately or together as haplotypes. So in the Chinese population only APOE -491 promoter alleles confer significant risk of AD independent of epsilon 4 status.
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Affiliation(s)
- J D Yang
- Shanghai Research Centre of Life Sciences, Chinese Academy of Sciences, Shanghai, China
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43
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Weidenhammer EM, Kahl BF, Wang L, Wang L, Duhon M, Jackson JA, Slater M, Xu X. Multiplexed, Targeted Gene Expression Profiling and Genetic Analysis on Electronic Microarrays. Clin Chem 2002. [DOI: 10.1093/clinchem/48.11.1873] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractBackground: Electronic microarrays comprise independent microelectrode test sites that can be electronically biased positive or negative, or left neutral, to move and concentrate charged molecules such as DNA and RNA to one or more test sites. We developed a protocol for multiplexed gene expression profiling of mRNA targets that uses electronic field-facilitated hybridization on electronic microarrays.Methods: A multiplexed, T7 RNA polymerase-mediated amplification method was used for expression profiling of target mRNAs from total cellular RNA; targets were detected by hybridization to sequence-specific capture oligonucleotides on electronic microarrays. Activation of individual test sites on the electronic microarray was used to target hybridization to designated subsets of sites and allow comparisons of target concentrations in different samples. We used multiplexed amplification and electronic field-facilitated hybridization to analyze expression of a model set of 10 target genes in the U937 cell line during lipopolysaccharide-mediated differentiation. Performance of multiple genetic analyses (single-nucleotide polymorphism detection, gene expression profiling, and splicing isoform detection) on a single electronic microarray was demonstrated using the ApoE and ApoER2 genes as a model system.Results: Targets were detected after a 2-min hybridization reaction. With noncomplementary capture probes, no signal was detectable. Twofold changes in target concentration were detectable throughout the (∼64-fold) range of concentrations tested. Levels of 10 targets were analyzed side by side across seven time points. By confining electronic activation to subsets of test sites, polymorphism detection, expression profiling, and splicing isoform analysis were performed on a single electronic microarray.Conclusions: Microelectronic array technology provides specific target detection and quantification with advantages over currently available methodologies for targeted gene expression profiling and combinatorial genomics testing.
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Affiliation(s)
- Elaine M Weidenhammer
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Brenda F Kahl
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Ling Wang
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Larry Wang
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Melanie Duhon
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Jo Ann Jackson
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Matthew Slater
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
| | - Xiao Xu
- Department of Research and Development, Nanogen, Inc., 10398 Pacific Center Ct., San Diego, CA 92121
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Abstract
The constant and rapid increase of life expectancy in western countries is associated with a major ageing of our populations. In these conditions, we can expect an epidemic progression of most chronic diseases, especially cardiovascular, neurodegenerative and metabolic disorders, the main causes of death in the world. The global burden of these diseases will have a dramatic impact on the health and on the socio-economical context of our societies. From a global point of view, the occurrence and progression of these multifactorial diseases rely upon the nature and intensity of the environmental determinants we are exposed to all life long, but also to our individual genetic susceptibility. Through the determination of this higher susceptibility to an environmental risk factor and the understanding of its mechanisms of action, prevention and management efforts will be better focused. In such multifactorial affections, the development and the transmission of the disease do not follow the simple laws of monogenic Mendelian models. The complexity of this transmission is associated with the influence, at various degrees, of several genes and of a close interaction between this particular genetic susceptibility and environmental risk factors. With the recent development of automated and high throughput molecular biology techniques and their use in epidemiological studies, gene expression regulation and post genomic studies, the determination of sub-groups facing a higher individual genetic susceptibility has begun. This determination will offer new clues for a better-targeted disease management.
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Affiliation(s)
- Philippe Amouyel
- INSERM U508, Institut Pasteur de Lille, 1, rue Calmette, 59019 Lille, France.
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45
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Chartier-Harlin MC, Araria-Goumidi L, Lambert JC. Les formes tardivesde la maladie d’Alzheimer : de la génétique à la biologie. Med Sci (Paris) 2002. [DOI: 10.1051/medsci/20021867709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Alvarez-Arcaya A, Combarros O, Llorca J, Sánchez-Guerra M, Berciano J, Fernández-Luna JL. The --491 TT apolipoprotein E promoter polymorphism is associated with reduced risk for sporadic Alzheimer's disease. Neurosci Lett 2001; 304:204-8. [PMID: 11343837 DOI: 10.1016/s0304-3940(01)01790-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Homozygosity for the A allele of the -491 A/T apolipoprotein E (APOE) promoter polymorphism has recently been reported to be associated with sporadic Alzheimer's disease (AD). Two hundred and fifty one patients with AD and an equal number of controls derived from the same region in a Spanish population, were genotyped for -491 A/T and epsilon2/epsilon3/epsilon4 APOE polymorphisms. We did not detect an elevated -491 AA genotype frequency when comparing AD cases to controls. In contrast, persons homozygous for the T allele were at a significantly reduced risk of AD (odds ratio of 0.10, P=0.006). Multiple logistic regression analysis indicated that the -491 TT polymorphism added information on the risk of AD which was independent of that of the APOE epsilon4 allele.
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Affiliation(s)
- A Alvarez-Arcaya
- Service of Neurology, University Hospital Marqués de Valdecilla, 39008 Santander, Spain
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47
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Berr C, Lambert JC, Sazdovitch V, Amouyel P, Chartier-Harlin MC, Mohr M, Heldt N, Kiesmann M, Hauw JJ. Neuropathological epidemiology of cerebral aging: a study of two genetic polymorphisms. Neurobiol Aging 2001; 22:227-35. [PMID: 11182472 DOI: 10.1016/s0197-4580(00)00227-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We studied whether ApoE and -219 GT (ApoE promoter) polymorphism modulates neurofibrillary tangle (NFT) and senile plaque (SP) development in aging among 190 non-institutionalized individuals (mean age 79.5 years). Analysis revealed that the mean Braak stage was higher in epsilon4 allele carriers. Once individuals with Braak stage V were excluded (n = 5), relationships between NFT and the two genotypes studied were weak, whereas in epsilon4 allele carriers, the risk of SP was multiplied by 4 to 7 in four areas (CA1, subiculum, isocortex and entorhinal cortex). This association was more pronounced in subjects under 80 years and was also observed when analysis was restricted to Braak stages 0, I and II. Epsilon 2 allele carriers appeared to have fewer lesions but, due to limited numbers, this trend was not significant. In two regions (CA1, subiculum), the number of SP increased significantly for individuals who were homozygous for the T allele of -219 GT. However the association was no longer significant when controlling for ApoE epsilon4. It should be noted that the brain of elderly subjects carrying one epsilon4 allele may not undergo senile changes.
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Affiliation(s)
- C Berr
- INSERM U360, Recherches Epidémiologiques en Neurologie et Psychopathologie, Hôpital de La Salpêtrière, 75651 Cedex 13, Paris, France.
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48
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Abstract
Alzheimer's disease is the most frequent cause of dementia. Family and twin studies have suggested that genetic factors play a role in Alzheimer's disease development. Some Alzheimer's disease cases show an autosomal dominant inheritance pattern and thus allow the discovery of major disease genes. However, most Alzheimer's disease cases are sporadic. These cases are mainly due to the effects of several different genes and of interactions between genetic susceptibility factors and environmental factors. Such interactions are illustrated by the apolipoprotein E epsilon4 allele, associated with a higher risk of Alzheimer's disease. Other genetic susceptibility factors have been reported but variously confirmed in Alzheimer's disease: apolipoprotein E receptors, alpha2-macroglobulin or angiotensin I converting enzyme genes. Thus, except for a small percentage of Alzheimer's disease cases with a dominant inheritance pattern, the genetic component of the vast majority of cases is underlain by complex interactions of genetic susceptibility factors and environmental conditions.
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Affiliation(s)
- F Richard
- INSERM 508, Institut Pasteur de Lille, 1 rue Calmette, 59019 Cedex, Lille, France
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49
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Fullerton SM, Clark AG, Weiss KM, Nickerson DA, Taylor SL, Stengârd JH, Salomaa V, Vartiainen E, Perola M, Boerwinkle E, Sing CF. Apolipoprotein E variation at the sequence haplotype level: implications for the origin and maintenance of a major human polymorphism. Am J Hum Genet 2000; 67:881-900. [PMID: 10986041 PMCID: PMC1287893 DOI: 10.1086/303070] [Citation(s) in RCA: 250] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2000] [Accepted: 08/10/2000] [Indexed: 11/03/2022] Open
Abstract
Three common protein isoforms of apolipoprotein E (apoE), encoded by the epsilon2, epsilon3, and epsilon4 alleles of the APOE gene, differ in their association with cardiovascular and Alzheimer's disease risk. To gain a better understanding of the genetic variation underlying this important polymorphism, we identified sequence haplotype variation in 5.5 kb of genomic DNA encompassing the whole of the APOE locus and adjoining flanking regions in 96 individuals from four populations: blacks from Jackson, MS (n=48 chromosomes), Mayans from Campeche, Mexico (n=48), Finns from North Karelia, Finland (n=48), and non-Hispanic whites from Rochester, MN (n=48). In the region sequenced, 23 sites varied (21 single nucleotide polymorphisms, or SNPs, 1 diallelic indel, and 1 multiallelic indel). The 22 diallelic sites defined 31 distinct haplotypes in the sample. The estimate of nucleotide diversity (site-specific heterozygosity) for the locus was 0.0005+/-0.0003. Sequence analysis of the chimpanzee APOE gene showed that it was most closely related to human epsilon4-type haplotypes, differing from the human consensus sequence at 67 synonymous (54 substitutions and 13 indels) and 9 nonsynonymous fixed positions. The evolutionary history of allelic divergence within humans was inferred from the pattern of haplotype relationships. This analysis suggests that haplotypes defining the epsilon3 and epsilon2 alleles are derived from the ancestral epsilon4s and that the epsilon3 group of haplotypes have increased in frequency, relative to epsilon4s, in the past 200,000 years. Substantial heterogeneity exists within all three classes of sequence haplotypes, and there are important interpopulation differences in the sequence variation underlying the protein isoforms that may be relevant to interpreting conflicting reports of phenotypic associations with variation in the common protein isoforms.
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Affiliation(s)
- S M Fullerton
- Institute of Molecular Evolutionary Genetics, Department of Biology, and Department of Anthropology, Pennsylvania State University, University Park, PA 16802, USA.
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Abstract
Alzheimer's disease, the most frequent form of senile dementia, presents in the vast majority of cases as a multifactorial trait, where a series of genetic and environmental risk factors converge. The increasing body of data, both epidemiological and functional, is strengthening the evidence that apolipoprotein E (APOE, gene; apoE, protein) is a true susceptibility factor for the onset of the common form of Alzheimer's disease. The E4 isoform of apoE remains to date as the main genetic risk factor for the disease, although the mechanisms responsible for this association are not well understood. It is also clear that apoE4 is not necessary or sufficient to cause the disease, indicating that other risk and protecting factors exist. ApoE is upregulated in response to nervous system injury, suggesting that it could have a neuroprotective role; on the other hand, there is evidence indicating that apoE is neurotoxic when present at high levels. Thus, apoE levels seem to be relevant for the functionality of the protein. The APOE proximal promoter hosts numerous regulatory elements, raising the possibility that polymorphisms in this region could produce variation in apoE levels by altering APOE transcriptional activity, which could finally result in AD susceptibility. We will review here the current evidence on the relationship between APOE proximal promoter polymorphisms, APOE gene transcriptional activity and apoE protein levels, and risk for AD.
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Affiliation(s)
- M J Bullido
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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