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Sahu B, Nookala S, Floden AM, Ambhore NS, Sathish V, Klug MG, Combs CK. House dust mite-induced asthma exacerbates Alzheimer's disease changes in the brain of the App NL-G-F mouse model of disease. Brain Behav Immun 2024; 121:365-383. [PMID: 39084541 DOI: 10.1016/j.bbi.2024.07.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 07/19/2024] [Accepted: 07/28/2024] [Indexed: 08/02/2024] Open
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) plaques, neuroinflammation, and neuronal death. Besides aging, various comorbidities increase the risk of AD, including obesity, diabetes, and allergic asthma. Epidemiological studies have reported a 2.17-fold higher risk of dementia in asthmatic patients. However, the molecular mechanism(s) underlying this asthma-associated AD exacerbation is unknown. This study was designed to explore house dust mite (HDM)-induced asthma effects on AD-related brain changes using the AppNL-G-F transgenic mouse model of disease. Male and female 8-9 months old C57BL/6J wild type and AppNL-G-F mice were exposed to no treatment, saline sham, or HDM extract every alternate day for 16 weeks for comparison across genotypes and treatment. Mice were euthanized at the end of the experiment, and broncho-alveolar lavage fluid (BALF), blood, lungs, and brains were collected. BALF was used to quantify immune cell phenotype, cytokine levels, total protein content, lactate dehydrogenase (LDH) activity, and total IgE. Lungs were sectioned and stained with hematoxylin and eosin, Alcian blue, and Masson's trichrome. Serum levels of cytokines and soluble Aβ1-40/42 were quantified. Brains were sectioned and immunostained for Aβ, GFAP, CD68, and collagen IV. Finally, frozen hippocampi and temporal cortices were used to perform Aβ ELISAs and cytokine arrays, respectively. HDM exposure led to increased levels of inflammatory cells, cytokines, total protein content, LDH activity, and total IgE in the BALF, as well as increased pulmonary mucus and collagen staining in both sexes and genotypes. Levels of serum cytokines increased in all HDM-exposed groups. Serum from the AppNL-G-F HDM-induced asthma group also had significantly increased soluble Aβ1-42 levels in both sexes. In agreement with this peripheral change, hippocampi from asthma-induced male and female AppNL-G-F mice demonstrated elevated Aβ plaque load and increased soluble Aβ 1-40/42 and insoluble Aβ 1-40 levels. HDM exposure also increased astrogliosis and microgliosis in both sexes of AppNL-G-F mice, as indicated by GFAP and CD68 immunoreactivity, respectively. Additionally, HDM exposure elevated cortical levels of several cytokines in both sexes and genotypes. Finally, HDM-exposed groups also showed a disturbed blood-brain-barrier (BBB) integrity in the hippocampus of AppNL-G-F mice, as indicated by decreased collagen IV immunoreactivity. HDM exposure was responsible for an asthma-like condition in the lungs that exacerbated Aβ pathology, astrogliosis, microgliosis, and cytokine changes in the brains of male and female AppNL-G-F mice that correlated with reduced BBB integrity. Defining mechanisms of asthma effects on the brain may identify novel therapeutic targets for asthma and AD.
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Affiliation(s)
- Bijayani Sahu
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, 1301 N Columbia Road, Grand Forks, ND 58202-9037, USA
| | - Suba Nookala
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, 1301 N Columbia Road, Grand Forks, ND 58202-9037, USA
| | - Angela M Floden
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, 1301 N Columbia Road, Grand Forks, ND 58202-9037, USA
| | - Nilesh S Ambhore
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health and Human Sciences, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Venkatachalem Sathish
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health and Human Sciences, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Marilyn G Klug
- Department of Population health, School of Medicine and Health Sciences, USA
| | - Colin K Combs
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, 1301 N Columbia Road, Grand Forks, ND 58202-9037, USA.
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Velezmoro Jauregui G, Vukić D, Onyango IG, Arias C, Novotný JS, Texlová K, Wang S, Kovačovicova KL, Polakova N, Zelinkova J, Čarna M, Lacovich V, Head BP, Havas D, Mistrik M, Zorec R, Verkhratsky A, Keegan L, O'Connell MA, Rissman R, Stokin GB. Amyloid precursor protein induces reactive astrogliosis. Acta Physiol (Oxf) 2024; 240:e14142. [PMID: 38584589 DOI: 10.1111/apha.14142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 04/09/2024]
Abstract
AIM Astrocytes respond to stressors by acquiring a reactive state characterized by changes in their morphology and function. Molecules underlying reactive astrogliosis, however, remain largely unknown. Given that several studies observed increase in the Amyloid Precursor Protein (APP) in reactive astrocytes, we here test whether APP plays a role in reactive astrogliosis. METHODS We investigated whether APP instigates reactive astroglios by examining in vitro and in vivo the morphology and function of naive and APP-deficient astrocytes in response to APP and well-established stressors. RESULTS Overexpression of APP in cultured astrocytes led to remodeling of the intermediate filament network, enhancement of cytokine production, and activation of cellular programs centered around the interferon (IFN) pathway, all signs of reactive astrogliosis. Conversely, APP deletion abrogated remodeling of the intermediate filament network and blunted expression of IFN-stimulated gene products in response to lipopolysaccharide. Following traumatic brain injury (TBI), mouse reactive astrocytes also exhibited an association between APP and IFN, while APP deletion curbed the increase in glial fibrillary acidic protein observed canonically in astrocytes in response to TBI. CONCLUSIONS The APP thus represents a candidate molecular inducer and regulator of reactive astrogliosis. This finding has implications for understanding pathophysiology of neurodegenerative and other diseases of the nervous system characterized by reactive astrogliosis and opens potential new therapeutic avenues targeting APP and its pathways to modulate reactive astrogliosis.
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Affiliation(s)
- Gretsen Velezmoro Jauregui
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Dragana Vukić
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Faculty of Science, National Centre for Biomedical Research, Masaryk University, Brno, Czech Republic
| | - Isaac G Onyango
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Carlos Arias
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Jan S Novotný
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Kateřina Texlová
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Shanshan Wang
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, La Jolla, California, USA
| | | | - Natalie Polakova
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jana Zelinkova
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Maria Čarna
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Valentina Lacovich
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Brian P Head
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, La Jolla, California, USA
| | | | - Martin Mistrik
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Robert Zorec
- Laboratory of Neuroendocrinology, Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
- Celica Biomedical, Technology Park, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Achucarro Centre for Neuroscience, IIKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning Province, China
| | - Liam Keegan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Mary A O'Connell
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Robert Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Gorazd B Stokin
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
- Department of Neurology, Gloucestershire Royal Hospital, Gloucestershire NHS Foundation Trust, Gloucester, UK
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Jauregui GV, Vukić D, Onyango IG, Arias C, Novotný JS, Texlová K, Wang S, Kovačovicova KL, Polakova N, Zelinkova J, Čarna M, Strašil VL, Head BP, Havas D, Mistrik M, Zorec R, Verkhratsky A, Keegan L, O'Connel M, Rissman R, Stokin GB. Amyloid precursor protein induces reactive astrogliosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.571817. [PMID: 38187544 PMCID: PMC10769227 DOI: 10.1101/2023.12.18.571817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
We present in vitro and in vivo evidence demonstrating that Amyloid Precursor Protein (APP) acts as an essential instigator of reactive astrogliosis. Cell-specific overexpression of APP in cultured astrocytes led to remodelling of the intermediate filament network, enhancement of cytokine production and activation of cellular programs centred around the interferon (IFN) pathway, all signs of reactive astrogliosis. Conversely, APP deletion in cultured astrocytes abrogated remodelling of the intermediate filament network and blunted expression of IFN stimulated gene (ISG) products in response to lipopolysaccharide (LPS). Following traumatic brain injury (TBI), mouse reactive astrocytes also exhibited an association between APP and IFN, while APP deletion curbed the increase in glial fibrillary acidic protein (GFAP) observed canonically in astrocytes in response to TBI. Thus, APP represents a molecular inducer and regulator of reactive astrogliosis.
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Affiliation(s)
- Gretsen Velezmoro Jauregui
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Dragana Vukić
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomedical Research, Faculty of Science, Masaryk University, Brno Czech Republic
| | - Isaac G Onyango
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Carlos Arias
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jan S Novotný
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Kateřina Texlová
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Shanshan Wang
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, San Diego, USA
| | | | - Natalie Polakova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jana Zelinkova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Maria Čarna
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | | | - Brian P Head
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, San Diego, USA
| | | | - Martin Mistrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Robert Zorec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Celica Biomedical, Technology Park, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Achucarro Centre for Neuroscience, IIKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Stem Cell Biology, State Research Institute Centre for innovative Medicine, Vilnius, Lithuania
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning Province, China
| | - Liam Keegan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Mary O'Connel
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Robert Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Gorazd B Stokin
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
- Department of Neurology, Gloucestershire Royal Hospital, Gloucestershire NHS Foundation Trust, Gloucester, UK
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Dai L, Shen Y. Insights into T-cell dysfunction in Alzheimer's disease. Aging Cell 2021; 20:e13511. [PMID: 34725916 PMCID: PMC8672785 DOI: 10.1111/acel.13511] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/22/2021] [Accepted: 10/22/2021] [Indexed: 12/11/2022] Open
Abstract
T cells, the critical immune cells of the adaptive immune system, are often dysfunctional in Alzheimer's disease (AD) and are involved in AD pathology. Reports highlight neuroinflammation as a crucial modulator of AD pathogenesis, and aberrant T cells indirectly contribute to neuroinflammation by secreting proinflammatory mediators via direct crosstalk with glial cells infiltrating the brain. However, the mechanisms underlying T‐cell abnormalities in AD appear multifactorial. Risk factors for AD and pathological hallmarks of AD have been tightly linked with immune responses, implying the potential regulatory effects of these factors on T cells. In this review, we discuss how the risk factors for AD, particularly Apolipoprotein E (ApoE), Aβ, α‐secretase, β‐secretase, γ‐secretase, Tau, and neuroinflammation, modulate T‐cell activation and the association between T cells and pathological AD hallmarks. Understanding these associations is critical to provide a comprehensive view of appropriate therapeutic strategies for AD.
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Affiliation(s)
- Linbin Dai
- Institute on Aging and Brain Disorders The First Affiliated Hospital of USTC Division of Life Sciences and Medicine University of Sciences and Technology of China Hefei China
- Neurodegenerative Disease Research Center University of Science and Technology of China Hefei China
- Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Hefei China
| | - Yong Shen
- Institute on Aging and Brain Disorders The First Affiliated Hospital of USTC Division of Life Sciences and Medicine University of Sciences and Technology of China Hefei China
- Neurodegenerative Disease Research Center University of Science and Technology of China Hefei China
- Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Hefei China
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Ullah R, Park TJ, Huang X, Kim MO. Abnormal amyloid beta metabolism in systemic abnormalities and Alzheimer's pathology: Insights and therapeutic approaches from periphery. Ageing Res Rev 2021; 71:101451. [PMID: 34450351 DOI: 10.1016/j.arr.2021.101451] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 08/12/2021] [Accepted: 08/19/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is an age-associated, multifactorial neurodegenerative disorder that is incurable. Despite recent success in treatments that partially improve symptomatic relief, they have failed in most clinical trials. Re-holding AD for accurate diagnosis and treatment is widely known as a challenging task. Lack of knowledge of basic molecular pathogenesis might be a possible reason for ineffective AD treatment. Historically, a majority of therapy-based studies have investigated the role of amyloid-β (Aβ peptide) in the central nervous system (CNS), whereas less is known about Aβ peptide in the periphery in AD. In this review, we provide a comprehensive summary of the current understanding of Aβ peptide metabolism (anabolism and catabolism) in the brain and periphery. We show that the abnormal metabolism of Aβ peptide is significantly linked with central-brain and peripheral abnormalities; the interaction between peripheral Aβ peptide metabolism and peripheral abnormalities affects central-brain Aβ peptide metabolism, suggesting the existence of significant communication between these two pathways of Aβ peptide metabolism. This close interaction between the central brain and periphery in abnormal Aβ peptide metabolism plays a key role in the development and progression of AD. In conclusion, we need to obtain a full understanding of the dynamic roles of Aβ peptide at the molecular level in both the brain and periphery in relation to the pathology of AD. This will not only provide new information regarding the complex disease pathology, but also offer potential new clues to improve therapeutic strategies and diagnostic biomarkers for the successful treatment of AD.
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Platelet APP Processing: Is It a Tool to Explore the Pathophysiology of Alzheimer's Disease? A Systematic Review. Life (Basel) 2021; 11:life11080750. [PMID: 34440494 PMCID: PMC8401829 DOI: 10.3390/life11080750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 11/16/2022] Open
Abstract
The processing of the amyloid precursor protein (APP) is a critical event in the formation of amyloid plaques. Platelets contain most of the enzymatic machinery required for APP processing and correlates of intracerebral abnormalities have been demonstrated in platelets of patients with AD. The goal of the present paper was to analyze studies exploring platelet APP metabolism in Alzheimer's disease patients trying to assess potential reliable peripheral biomarkers, to offer new therapeutic solutions and to understand the pathophysiology of the AD. According to the PRISMA guidelines, we performed a systematic review through the PubMed database up to June 2020 with the search terms: "((((((APP) OR Amyloid Precursor Protein) OR AbetaPP) OR Beta Amyloid) OR Amyloid Beta) OR APP-processing) AND platelet". Thirty-two studies were included in this systematic review. The papers included are analytic observational studies, namely twenty-nine cross sectional studies and three longitudinal studies, specifically prospective cohort study. The studies converge in an almost unitary way in affirming that subjects with AD show changes in APP processing compared to healthy age-matched controls. However, the problem of the specificity and sensitivity of these biomarkers is still at issue and would deserve to be deepened in future studies.
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Bram JMDF, Talib LL, Joaquim HPG, Sarno TA, Gattaz WF, Forlenza OV. Protein levels of ADAM10, BACE1, and PSEN1 in platelets and leukocytes of Alzheimer's disease patients. Eur Arch Psychiatry Clin Neurosci 2019; 269:963-972. [PMID: 29845446 DOI: 10.1007/s00406-018-0905-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 05/22/2018] [Indexed: 12/31/2022]
Abstract
The clinical diagnosis of Alzheimer's disease (AD) is a probabilistic formulation that may lack accuracy particularly at early stages of the dementing process. Abnormalities in amyloid-beta precursor protein (APP) metabolism and in the level of APP secretases have been demonstrated in platelets, and to a lesser extent in leukocytes, of AD patients, with conflicting results. The aim of the present study was to compare the protein level of the APP secretases A-disintegrin and metalloprotease 10 (ADAM10), Beta-site APP-cleaving enzyme 1 (BACE1), and presenilin-1 (PSEN1) in platelets and leukocytes from 20 non-medicated older adults with AD and 20 healthy elders, and to determine the potential use of these biomarkers to discriminate cases of AD from controls. The protein levels of all APP secretases were significantly higher in platelets compared to leukocytes. We found statistically a significant decrease in ADAM10 (52.5%, p < 0.0001) and PSEN1 (32%, p = 0.02) in platelets from AD patients compared to controls, but not in leukocytes. Combining all three secretases to generate receiver-operating characteristic (ROC) curves, we found a good discriminatory effect (AD vs. controls) when using platelets (the area under the curve-AUC-0.90, sensitivity 88.9%, specificity 66.7%, p = 0.003), but not in leukocytes (AUC 0.65, sensitivity 77.8%, specificity 50.0%, p = 0.2). Our findings indicate that platelets represent a better biological matrix than leukocytes to address the peripheral level of APP secretases. In addition, combining the protein level of ADAM10, BACE1, and PSEN1 in platelets, yielded a good accuracy to discriminate AD from controls.
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Affiliation(s)
- Jessyka Maria de França Bram
- Laboratorio de Neurociencias (LIM-27), Departamento e Instituto de Psiquiatria, Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, Rua Doutor Ovídio Pires de Campos 785, São Paulo, SP, 05403-010, Brazil
| | - Leda Leme Talib
- Laboratorio de Neurociencias (LIM-27), Departamento e Instituto de Psiquiatria, Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, Rua Doutor Ovídio Pires de Campos 785, São Paulo, SP, 05403-010, Brazil
| | - Helena Passarelli Giroud Joaquim
- Laboratorio de Neurociencias (LIM-27), Departamento e Instituto de Psiquiatria, Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, Rua Doutor Ovídio Pires de Campos 785, São Paulo, SP, 05403-010, Brazil
| | - Tamires Alves Sarno
- Laboratorio de Neurociencias (LIM-27), Departamento e Instituto de Psiquiatria, Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, Rua Doutor Ovídio Pires de Campos 785, São Paulo, SP, 05403-010, Brazil
| | - Wagner Farid Gattaz
- Laboratorio de Neurociencias (LIM-27), Departamento e Instituto de Psiquiatria, Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, Rua Doutor Ovídio Pires de Campos 785, São Paulo, SP, 05403-010, Brazil
| | - Orestes Vicente Forlenza
- Laboratorio de Neurociencias (LIM-27), Departamento e Instituto de Psiquiatria, Hospital das Clínicas da Faculdade de Medicina da USP (HCFMUSP), Faculdade de Medicina, Universidade de Sao Paulo, Rua Doutor Ovídio Pires de Campos 785, São Paulo, SP, 05403-010, Brazil.
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Amyloid precursor protein and amyloid precursor-like protein 2 in cancer. Oncotarget 2017; 7:19430-44. [PMID: 26840089 PMCID: PMC4991393 DOI: 10.18632/oncotarget.7103] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/23/2016] [Indexed: 12/22/2022] Open
Abstract
Amyloid precursor protein (APP) and its family members amyloid precursor-like protein 1 (APLP1) and amyloid precursor-like protein 2 (APLP2) are type 1 transmembrane glycoproteins that are highly conserved across species. The transcriptional regulation of APP and APLP2 is similar but not identical, and the cleavage of both proteins is regulated by phosphorylation. APP has been implicated in Alzheimer's disease causation, and in addition to its importance in neurology, APP is deregulated in cancer cells. APLP2 is likewise overexpressed in cancer cells, and APLP2 and APP are linked to increased tumor cell proliferation, migration, and invasion. In this present review, we discuss the unfolding account of these APP family members’ roles in cancer progression and metastasis.
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Mihov D, Raja E, Spiess M. Chondroitin Sulfate Accelerates Trans-Golgi-to-Surface Transport of Proteoglycan Amyloid Precursor Protein. Traffic 2015; 16:853-70. [PMID: 25951880 DOI: 10.1111/tra.12294] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/15/2015] [Accepted: 04/15/2015] [Indexed: 11/28/2022]
Abstract
The amyloid precursor protein (APP) is a membrane protein implicated in the pathogenesis of Alzheimer's disease. APP is a part-time proteoglycan, as splice variants lacking exon 15 are modified by a chondroitin sulfate glycosaminoglycan (GAG) chain. Investigating the effect of the GAG chain on the trafficking of APP in non-polarized cells, we found it to increase the steady-state surface-to-intracellular distribution, to reduce the rate of endocytosis and to accelerate transport kinetics from the trans-Golgi network (TGN) to the plasma membrane. Deletion of the cytosolic domain resulted in delayed surface arrival of GAG-free APP, but did not affect the rapid export kinetics of the proteoglycan form. Protein-free GAG chains showed the same TGN-to-cell surface transport kinetics as proteoglycan APP. Endosome ablation experiments were performed to distinguish between indirect endosomal and direct pathways to the cell surface. Surprisingly, TGN-to-cell surface transport of both GAG-free and proteoglycan APP was found to be indirect via transferrin-positive endosomes. Our results show that GAGs act as alternative sorting determinants in cellular APP transport that are dominant over cytoplasmic signals and involve distinct sorting mechanisms.
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Affiliation(s)
- Deyan Mihov
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Eva Raja
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
| | - Martin Spiess
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056, Basel, Switzerland
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Plagg B, Marksteiner J, Kniewallner KM, Humpel C. Platelet dysfunction in hypercholesterolemia mice, two Alzheimer's disease mouse models and in human patients with Alzheimer's disease. Biogerontology 2015; 16:543-58. [PMID: 25947203 PMCID: PMC4487346 DOI: 10.1007/s10522-015-9580-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 04/28/2015] [Indexed: 12/22/2022]
Abstract
Alzheimer’s disease (AD) is a severe neurodegenerative disorder characterized mainly by accumulation of amyloid-β plaques and neurofibrillary tangles, synaptic and neuronal loss. Blood platelets contain the neurotransmitter serotonin and amyloid-precursor protein (APP), and may thus be useful as a peripheral biomarker for AD. The aim of the present study was to functionally characterize platelets by FACS, to examine alterations in APP expression and secretion, and to measure serotonin levels in hypercholesterolemia mice with AD-like pathology and in two AD mouse models, the triple transgenic AD model (3xTg) and the APP overexpressing AD model with the Swedish–Dutch–Iowa mutations (APP_SweDI). These data are supplemented with epidermal growth factor (EGF) levels and compared with changes observed in platelets of patients with AD. We observed decreased platelet APP isoforms in 3xTg mice and patients with AD when analysed by means of Western blot. In patients, a significant increase of APP levels was observed when assessed by ELISA. Secreted APPβ proved to be altered amongst all three animal models of AD at different time points and in human patients with AD. Serotonin levels were only reduced in 7 and 14 month old 3xTg mice. Moreover, we found significantly lower EGF levels in human AD patients and could thereby reproduce previous findings. Taken together, our data confirm that platelets are dysfunctional in AD, however, results from AD animal models do not coincide in all aspects, and markedly differ when compared to AD patients. We support previous data that APP, as well as EGF, could become putative biomarkers for diagnosing AD in human platelets.
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Affiliation(s)
- Barbara Plagg
- Laboratory of Psychiatry and Experimental Alzheimer's Research, Department of Psychiatry and Psychotherapy, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria
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Krstic D, Knuesel I. The airbag problem-a potential culprit for bench-to-bedside translational efforts: relevance for Alzheimer's disease. Acta Neuropathol Commun 2013; 1:62. [PMID: 24252346 PMCID: PMC3893418 DOI: 10.1186/2051-5960-1-62] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/16/2013] [Indexed: 11/10/2022] Open
Abstract
For the last 20 years, the "amyloid cascade hypothesis" has dominated research aimed at understanding, preventing, and curing Alzheimer's disease (AD). During that time researchers have acquired an enormous amount of data and have been successful, more than 300 times, in curing the disease in animal model systems by treatments aimed at clearing amyloid deposits. However, to date similar strategies have not been successful in human AD patients. Hence, before rushing into further clinical trials with compounds that aim at lowering amyloid-beta (Aβ) levels in increasingly younger people, it would be of highest priority to re-assess the initial assumption that accumulation of Aβ in the brain is the primary pathological event driving AD. Here we question this assumption by highlighting experimental evidence in support of the alternative hypothesis suggesting that APP and Aβ are part of a neuronal stress/injury system, which is up-regulated to counteract inflammation/oxidative stress-associated neurodegeneration that could be triggered by a brain injury, chronic infections, or a systemic disease. In AD, this protective program may be overridden by genetic and other risk factors, or its maintenance may become dysregulated during aging. Here, we provide a hypothetical example of a hypothesis-driven correlation between car accidents and airbag release in analogy to the evolution of the amyloid focus and as a way to offer a potential explanation for the failure of the AD field to translate the success of amyloid-related therapeutic strategies in experimental models to the clinic.
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12
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Evin G, Li QX. Platelets and Alzheimer’s disease: Potential of APP as a biomarker. World J Psychiatry 2012; 2:102-13. [PMID: 24175176 PMCID: PMC3782192 DOI: 10.5498/wjp.v2.i6.102] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 07/13/2012] [Accepted: 07/23/2012] [Indexed: 02/05/2023] Open
Abstract
Platelets are the first peripheral source of amyloid precursor protein (APP). They possess the proteolytic machinery to produce Aβ and fragments similar to those produced in neurons, and thus offer an ex-vivo model to study APP processing and changes associated with Alzheimer’s disease (AD). Platelet process APP mostly through the α-secretase pathway to release soluble APP (sAPP). They produce small amounts of Aβ, predominantly Aβ40 over Aβ42. sAPP and Aβ are stored in α-granules and are released upon platelet activation by thrombin and collagen, and agents inducing platelet degranulation. A small proportion of full-length APP is present at the platelet surface and this increases by 3-fold upon platelet activation. Immunoblotting of platelet lysates detects APP as isoforms of 130 kDa and 106-110 kDa. The ratio of these of APP isoforms is significantly lower in patients with AD and mild cognitive impairment (MCI) than in healthy controls. This ratio follows a decrease that parallels cognitive decline and can predict conversion from MCI to AD. Alterations in the levels of α-secretase ADAM10 and in the enzymatic activities of α- and β-secretase observed in platelets of patients with AD are consistent with increased processing through the amyloidogenic pathway. β-APP cleaving enzyme activity is increased by 24% in platelet membranes of patients with MCI and by 17% in those with AD. Reports of changes in platelet APP expression with MCI and AD have been promising so far and merit further investigation as the search for blood biomarkers in AD, in particular at the prodromal stage, remains a priority and a challenge.
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Affiliation(s)
- Geneviève Evin
- Geneviève Evin, Qiao-Xin Li, Department of Pathology and Mental Health Research Institute, The University of Melbourne, Parkville 3010, Australia
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13
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Bailey AR, Hou H, Obregon DF, Tian J, Zhu Y, Zou Q, Nikolic WV, Bengtson M, Mori T, Murphy T, Tan J. Aberrant T-lymphocyte development and function in mice overexpressing human soluble amyloid precursor protein-α: implications for autism. FASEB J 2011; 26:1040-51. [PMID: 22085641 DOI: 10.1096/fj.11-195438] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Abnormalities in T-lymphocyte populations and function are observed in autism. Soluble amyloid precursor protein α (sAPP-α) is elevated in some patients with autism and is known to be produced by immune cells. In light of the well-established role of sAPP-α in proliferation, growth, and survival of neurons, we hypothesized an analogous role in the immune system. Thus, we explored whether sAPP-α could modulate immune development and function, especially aspects of the pinnacle cell of the adaptive arm of the immune system: the T cell. To do this, we generated mice overexpressing human sAPP-α and characterized elements of T-cell development, signal transduction, cytokine production, and innate/adaptive immune functions. Here, we report that transgenic sAPP-α-overexpressing (TgsAPP-α) mice displayed increased proportions of CD8(+) T cells, while effector memory T cells were decreased in the thymus. Overall apoptotic signal transduction was decreased in the thymus, an effect that correlated with dramatic elevations in Notch1 activation; while active-caspase-3/total-caspase-3 and Bax/Bcl-2 ratios were decreased. Greater levels of IFN-γ, IL-2, and IL-4 were observed after ex vivo challenge of TgsAPP-α mouse splenocytes with T-cell mitogen. Finally, after immunization, splenocytes from TgsAPP-α mice displayed decreased levels IFN-γ, IL-2, and IL-4, as well as suppressed ZAP70 activation, after recall antigen stimulation. Given elevated levels of circulating sAPP-α in some patients with autism, sAPP-α could potentially drive aspects of immune dysfunction observed in these patients, including dysregulated T-cell apoptosis, aberrant PI3K/AKT signaling, cytokine alterations, and impaired T-cell recall stimulation.
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Affiliation(s)
- Antoinette R Bailey
- Rashid Laboratory for Developmental Neurobiology, Silver Child Development Center, Department of Psychiatry and Neurosciences, College of Medicine, University of South Florida, 3515 E. Fletcher Ave. Tampa, FL 33613, USA
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Sambamurti K, Greig NH, Utsuki T, Barnwell EL, Sharma E, Mazell C, Bhat NR, Kindy MS, Lahiri DK, Pappolla MA. Targets for AD treatment: conflicting messages from γ-secretase inhibitors. J Neurochem 2011; 117:359-74. [PMID: 21320126 DOI: 10.1111/j.1471-4159.2011.07213.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Current evidence suggests that Alzheimer's disease (AD) is a multi-factorial disease that starts with accumulation of multiple proteins. We have previously proposed that inhibition of γ-secretase may impair membrane recycling causing neurodegeneration starting at synapses (Sambamurti K., Suram A., Venugopal C., Prakasam A., Zhou Y., Lahiri D. K. and Greig N. H. A partial failure of membrane protein turnover may cause Alzheimer's disease: a new hypothesis. Curr. Alzheimer Res., 3, 2006, 81). We also proposed familal AD mutations increase Aβ42 by inhibiting γ-secretase. Herein, we discuss the failure of Eli Lilly's γ-secretase inhibitor, semagacestat, in clinical trials in the light of our hypothesis, which extends the problem beyond toxicity of Aβ aggregates. We elaborate that γ-secretase inhibitors lead to accumulation of amyloid precursor protein C-terminal fragments that can later be processed by γ-secretase to yields bursts of Aβ to facilitate aggregation. Although we do not exclude a role for toxic Aβ aggregates, inhibition of γ-secretase can affect numerous substrates other than amyloid precursor protein to affect multiple pathways and the combined accumulation of multiple peptides in the membrane may impair its function and turnover. Taken together, protein processing and turnover pathways play an important role in maintaining cellular homeostasis and unless we clearly see consistent disease-related increase in their levels or activity, we need to focus on preserving their function rather than inhibiting them for treatment of AD and similar diseases.
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Affiliation(s)
- Kumar Sambamurti
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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15
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Spitzer P, Herrmann M, Klafki HW, Smirnov A, Lewczuk P, Kornhuber J, Wiltfang J, Maler JM. Phagocytosis and LPS alter the maturation state of β-amyloid precursor protein and induce different Aβ peptide release signatures in human mononuclear phagocytes. J Neuroinflammation 2010; 7:59. [PMID: 20929546 PMCID: PMC2958903 DOI: 10.1186/1742-2094-7-59] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 10/07/2010] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The classic neuritic β-amyloid plaque of Alzheimer's disease (AD) is typically associated with activated microglia and neuroinflammation. Similarly, cerebrovascular β-amyloid (Aβ) deposits are surrounded by perivascular macrophages. Both observations indicate a contribution of the mononuclear phagocyte system to the development of β-amyloid. METHODS Human CD14-positive mononuclear phagocytes were isolated from EDTA-anticoagulated blood by magnetic activated cell sorting. After a cultivation period of 72 hours in serum-free medium we assessed the protein levels of amyloid precursor protein (APP) as well as the patterns and the amounts of released Aβ peptides by ELISA or one-dimensional and two-dimensional urea-based SDS-PAGE followed by western immunoblotting. RESULTS We observed strong and significant increases in Aβ peptide release upon phagocytosis of acetylated low density lipoprotein (acLDL) or polystyrene beads and also after activation of the CD14/TLR4 pathway by stimulation with LPS. The proportion of released N-terminally truncated Aβ variants was increased after stimulation with polystyrene beads and acLDL but not after stimulation with LPS. Furthermore, strong shifts in the proportions of single Aβ1-40 and Aβ2-40 variants were detected resulting in a stimulus-specific Aβ signature. The increased release of Aβ peptides was accompanied by elevated levels of full length APP in the cells. The maturation state of APP was correlated with the release of N-terminally truncated Aβ peptides. CONCLUSIONS These findings indicate that mononuclear phagocytes potentially contribute to the various N-truncated Aβ variants found in AD β-amyloid plaques, especially under neuroinflammatory conditions.
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Affiliation(s)
- Philipp Spitzer
- Department of Psychiatry and Psychotherapy, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
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Maler JM, Spitzer P, Klafki HW, Esselmann H, Lewczuk P, Kornhuber J, Herrmann M, Wiltfang J. Distinct fractional Aβ release patterns in human mononuclear phagocytes. J Neuroimmunol 2009; 206:1-4. [DOI: 10.1016/j.jneuroim.2008.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/21/2008] [Accepted: 08/22/2008] [Indexed: 10/21/2022]
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17
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Greenberg SA. Comment on 'Interrelation of inflammation and APP in sIBM: IL-1 induces accumulation of -amyloid in skeletal muscle'. Brain 2008; 132:e106; author reply e107. [DOI: 10.1093/brain/awn163] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Schindowski K, Eckert A, Peters J, Gorriz C, Schramm U, Weinandi T, Maurer K, Frölich L, Müller WE. Increased T-cell reactivity and elevated levels of CD8+ memory T-cells in Alzheimer's disease-patients and T-cell hyporeactivity in an Alzheimer's disease-mouse model: implications for immunotherapy. Neuromolecular Med 2007; 9:340-54. [PMID: 17963048 DOI: 10.1007/s12017-007-8015-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2007] [Indexed: 12/11/2022]
Abstract
Neuroinflammation is observed in neurodegenerative diseases like Alzheimer's disease (AD). However, a little is known about the mechanisms of neural-immune interactions. The involvement of peripheral T-cell function in AD is still far from clear, though it plays an important role in immunotherapy. The aim of this study was to determine peripheral T-cell reactivity in AD patients and in an AD mouse model. Mitogenic activation via ligation of the T-cell receptor (TCR) with PHA-L was measured in T lymphocytes from AD patients and Thy1(APP 751SL) x HMG(PS1 M146L)-transgenic mice (APP x PS1). In order to uncover failures in TCR signaling, the TCR was also bypassed by PMA and ionomycin treatment. All patients were sporadic late onset cases and the transgenic mice expressed no mutant APP in lymphocytes, so that direct interactions of mutant APP on T-cell function can be excluded. CD4+ and CD8+ T-cell showed increased reactivity (tyrosine phosphorylation, CD69 expression, and proliferation) in AD, while APP x PS1 transgenic mice displayed hyporeactive CD8+ T-cells after TCR ligation. Increased levels of CD8+ T memory cells and down regulation of CD8 receptor were found in AD and the animal model. Anergic TCR uncoupling was associated with loss of MAPK signaling (p38, ERK1 and ERK2) in APP x PS1. Our data implicate the generation of reactive memory T-cell in AD and of anergic memory T-cells in transgenic mice and should be taken into concern when designing immunotherapy.
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Affiliation(s)
- Katharina Schindowski
- Institute of Pharmacology, Biocenter building N260, Johann Wolfgang-Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
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Fardilha M, Vieira SI, Barros A, Sousa M, Da Cruz e Silva OAB, Da Cruz e Silva EF. Differential Distribution of Alzheimer's Amyloid Precursor Protein Family Variants in Human Sperm. Ann N Y Acad Sci 2007; 1096:196-206. [PMID: 17405931 DOI: 10.1196/annals.1397.086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The Alzheimer's amyloid precursor protein (APP) is a type I transmembrane glycoprotein with receptor-like characteristics that originates the Abeta peptide by proteolytic processing. Abeta is potentially cytotoxic and the major component of the cerebral amyloid plaques in Alzheimer's disease (AD) patients. APP is known to be ubiquitously expressed in mammalian cells, with a broad tissue distribution, and Abeta deposition has been reported to occur also in many cells outside the nervous system. Although many putative functions have been suggested for APP, its precise physiological role remains to be elucidated. As several results point to a role of chronic inflammation in AD pathogenesis and suggest that AD might be a systemic disorder, the importance of APP function in non-neuronal cells/tissues has gained increased relevance. Previous studies have shown that amyloid precursor-like protein 2 (APLP2) is highly expressed in testis and sperm, but failed to unambiguously prove the presence of APP itself in mammalian sperm. The use of a battery of available antibodies that detect APP-specific epitopes or epitopes shared with other APP family members, revealed quite distinct distributions in human sperm. Our results are consistent with previous observations of APLP2 in sperm and unequivocally demonstrate the presence of APP itself in human sperm, thus suggesting a putative role for this important protein in sperm function.
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Affiliation(s)
- Margarida Fardilha
- Signal Transduction Laboratory, Centre for Cell Biology, University of Aveiro, Aveiro, Portugal
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Bayer TA, Wirths O, Majtényi K, Hartmann T, Multhaup G, Beyreuther K, Czech C. Key factors in Alzheimer's disease: beta-amyloid precursor protein processing, metabolism and intraneuronal transport. Brain Pathol 2006; 11:1-11. [PMID: 11145195 PMCID: PMC8098450 DOI: 10.1111/j.1750-3639.2001.tb00376.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
During the last years it has become evident that the beta-amyloid (Abeta) component of senile plaques may be the key molecule in the pathology of Alzheimer's disease (AD). The source and place of the neurotoxic action of Abeta, however, is still a matter of controversy. The precursor of the beta-amyloid peptide is the predominantly neuronal beta-amyloid precursor protein. We, and others, hypothesize that intraneuronal misregulation of APP leads to an accumulation of Abeta peptides in intracellular compartments. This accumulation impairs APP trafficking, which starts a cascade of pathological changes and causes the pyramidal neurons to degenerate. Enhanced Abeta secretion as a function of stressed neurons and remnants of degenerated neurons provide seeds for extracellular Abeta aggregates, which induce secondary degenerative events involving neighboring cells such as neurons, astroglia and macrophages/microglia. Beta-amyloid precursor protein has a pivotal role in Alzheimer's disease.
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Affiliation(s)
- T A Bayer
- Department of Psychiatry, University of Bonn Medical Center, Germany.
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22
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Fischer DF, Dijk R, Sluijs JA, Nair SM, Racchi M, Levelt CN, Leeuwen FW, Hol EM. Activation of the Notch pathway in Down syndrome: cross‐talk of Notch and APP. FASEB J 2005. [DOI: 10.1096/fj.04-3395com] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David F. Fischer
- Netherlands Institute for Brain Research Amsterdam The Netherlands
- Department of Functional GenomicsCenter for Neurogenomics and Cognitive Research (CNCR)Vrije Universiteit Amsterdam Amsterdam The Netherlands
| | - Renske Dijk
- Netherlands Institute for Brain Research Amsterdam The Netherlands
| | | | - Suresh M. Nair
- Netherlands Institute for Brain Research Amsterdam The Netherlands
| | - Marco Racchi
- Department of Experimental and Applied PharmacologyUniversity of Pavia Italy
| | | | - Fred W. Leeuwen
- Netherlands Institute for Brain Research Amsterdam The Netherlands
| | - Elly M. Hol
- Netherlands Institute for Brain Research Amsterdam The Netherlands
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Vehmas A, Lieu J, Pardo CA, McArthur JC, Gartner S. Amyloid precursor protein expression in circulating monocytes and brain macrophages from patients with HIV-associated cognitive impairment. J Neuroimmunol 2005; 157:99-110. [PMID: 15579286 DOI: 10.1016/j.jneuroim.2004.08.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2004] [Indexed: 11/30/2022]
Abstract
We examined amyloid precursor protein (APP) surface expression on circulating leukocytes and in brain tissues from normal individuals and HIV+ subjects with cognitive impairment. Most monocytes, and a subset of B-lymphocytes, expressed APP, while T-lymphocytes, granulocytes, and natural killer (NK) cells did not. CD14bright/CD16+ monocytes expressed the highest levels, and CD14dim/CD16+ cells were negative, suggesting a relationship with activation. Higher APP+ monocyte levels correlated with increased numbers of CD16+ monocytes, but not with the degree of cognitive impairment. Treatment of monocytes with M-CSF, but not LPS, upregulated APP expression. In the brain, APP appeared as axonal immunoreactivity and diffuse plaques, and APP+ perivascular macrophages were seen in cases with severe dementia. APP may facilitate monocyte entry into the brain.
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Affiliation(s)
- Ari Vehmas
- Department of Neurology, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287, USA
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Kawasumi M, Chiba T, Yamada M, Miyamae-Kaneko M, Matsuoka M, Nakahara J, Tomita T, Iwatsubo T, Kato S, Aiso S, Nishimoto I, Kouyama K. Targeted introduction of V642I mutation in amyloid precursor protein gene causes functional abnormality resembling early stage of Alzheimer's disease in aged mice. Eur J Neurosci 2004; 19:2826-38. [PMID: 15147316 DOI: 10.1111/j.0953-816x.2004.03397.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
While the exact aetiology of Alzheimer's disease (AD) is unknown, distinct genetic mutations have been identified for the rare cases of familial AD (FAD). V642I mutation in amyloid precursor protein (APP) co-segregates with FAD with perfect penetration, and the clinicopathological characteristics of patients with this mutation resemble that of sporadic AD. To examine the pathogenic process of this FAD-linked trait in vivo, we produced a mouse with the corresponding point mutation in the APP gene using homologous recombination and Cre-loxP site-specific recombination ('knock-in' technique). Mice with the heterozygous V642I-APP allele most precisely reflected the genotype of humans bearing this mutation. For the observation period of 2.5 years the mutants stayed apparently indistinguishable from the wild-type littermates. However, behavioural analysis revealed significantly deteriorated long-term memory in mutants when examined for the retention of spatial attention. Interestingly, acquisition of spatial memory was slightly affected but short-term working memory was not deteriorated at all. Histological examination was negative for formation of neuritic plaques or neurofibrillary tangles, whereas the relative amount of longer form of beta-amyloid species A beta 42(43) was significantly increased against that of the shorter form (A beta 40) in the mutant brain homogenates. We conclude that a V642I-APP mutant allele in aged mice confers functional components, but not organic components, of the AD-related phenotype that are observed in the early stage of AD. This V642I-APP knock-in mutant line may serve as a model to study the early pathogenic processes of AD in vivo and to develop therapeutics for this stage.
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Affiliation(s)
- Masaoki Kawasumi
- Department of Pharmacology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Sondag CM, Combs CK. Amyloid Precursor Protein Mediates Proinflammatory Activation of Monocytic Lineage Cells. J Biol Chem 2004; 279:14456-63. [PMID: 14732706 DOI: 10.1074/jbc.m313747200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alzheimer's disease is a progressive neurodegenerative disorder characterized by extracellular deposition of beta-amyloid (Abeta) peptide containing neuritic plaques. Abeta peptides are proteolytically derived from the membrane-bound amyloid precursor protein (APP). Although the function of APP is not entirely clear, previous studies demonstrate that neuronal APP colocalizes with beta(1) integrin receptors at sites of focal adhesion, suggesting that APP is involved in mediating neuronal process adhesion. Integrin-dependent adhesion is also a well-characterized component of immune cell proinflammatory activation. Using primary mouse microglia and the human monocytic cell line, THP-1, we have begun investigating the role of APP in integrin-dependent activation. Co-immunoprecipitation studies demonstrate that APP is recruited into a multi-receptor signaling complex during beta(1) integrin-mediated adhesion of monocytes. Stimulation induces a subsequent, specific recruitment of tyrosine phosphorylated proteins to APP, including Lyn and Syk. Antibody cross-linking of cell surface APP leads to a similar response characterized by activation and recruitment of tyrosine kinases to APP as well as subsequent activation of mitogen-activated protein kinases and increased proinflammatory protein levels. These data demonstrate that APP can act as a proinflammatory receptor in monocytic lineage cells and provide insight into the contribution of this protein to the inflammatory conditions described in Alzheimer's disease.
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Affiliation(s)
- Cindy M Sondag
- University of North Dakota School of Medicine and Health Sciences, Department of Pharmacology, Grand Forks, North Dakota 58202, USA
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26
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Maesako Y, Uchiyama T, Ohno H. Comparison of gene expression profiles of lymphoma cell lines from transformed follicular lymphoma, Burkitt's lymphoma and de novo diffuse large B-cell lymphoma. Cancer Sci 2003; 94:774-81. [PMID: 12967475 PMCID: PMC11160262 DOI: 10.1111/j.1349-7006.2003.tb01518.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2003] [Revised: 06/26/2003] [Accepted: 07/07/2003] [Indexed: 11/28/2022] Open
Abstract
To determine the specific gene expression in B-cell lymphoma subtypes, we compared expression profiles of cell lines from transformed follicular lymphoma (tFL), Epstein-Barr virus-negative (EBV(-)) Burkitt's lymphoma (BL) and EBV(+)BL. Complementary DNAs were synthesized from these cell lines and hybridized with the Atlas Human 1.2 Array membrane. Hierarchical clustering analysis based upon the levels of 43 genes highlighted characteristic expression patterns of the 3 lymphoma subtypes. Genes expressed at higher levels in tFL than EBV(-)BL and EBV(+)BL included calcium/calmodulin-dependent protein kinase I (CAMK1) and mitogen-activated protein kinase 10 (MAPK10). EBV(-)BL was characterized by high-level expression of amyloid beta precursor protein (APP), heat shock 27 kD protein 1 (HSPB1) and mothers against decapentaplegic homolog 1 (MADH1). Gardner-Rasheed feline sarcoma viral oncogene homolog (FGR) was the most significant gene to delineate EBV(+)BL. A subtype prediction algorithm using 34 genes correctly classified 22 (92%) of 24 lymphomas into FL/tFL, EBV(-)BL or EBV(+)BL. By comparison with normal reference B-cell materials, the expression patterns of the selected genes were characteristic of lymphomas. We extended the clustering analysis to cell lines from de novo diffuse large B-cell lymphoma (DLBCL). The DLBCL cell lines were either separated from the former 3 lymphoma subtypes or segregated with EBV(+)BL, possibly reflecting variable genetic abnormalities. The associations of CAMK1 with tFL, APP and MADH1 with EBV(-)BL, FGR with EBV(+)BL, and BCL2 with tFL and DLBCL were confirmed by real-time quantitative reverse transcriptase-mediated polymerase chain reaction assays. This study has provided new molecular markers, expressions of which are closely associated with B-cell lymphoma subtypes.
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MESH Headings
- B-Lymphocytes/physiology
- Biomarkers, Tumor/analysis
- Cell Line, Transformed/virology
- Cells, Cultured
- DNA, Complementary/genetics
- Epstein-Barr Virus Infections/virology
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic
- Herpesvirus 4, Human/pathogenicity
- Humans
- Lymphoma, B-Cell/genetics
- Lymphoma, Follicular/genetics
- Lymphoma, Large B-Cell, Diffuse/genetics
- Oligonucleotide Array Sequence Analysis
- RNA, Messenger/analysis
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Affiliation(s)
- Yoshitomo Maesako
- Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
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27
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Kimura A, Kakinuma K, Yonezawa S, Takahashi T. Expression of β-Amyloid Precursor Protein in the Porcine Ovary. Zoolog Sci 2000. [DOI: 10.2108/zsj.17.769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Meda L, Baron P, Prat E, Scarpini E, Scarlato G, Cassatella MA, Rossi F. Proinflammatory profile of cytokine production by human monocytes and murine microglia stimulated with beta-amyloid[25-35]. J Neuroimmunol 1999; 93:45-52. [PMID: 10378868 DOI: 10.1016/s0165-5728(98)00188-x] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Growing evidence indicates that amyloid (A beta) deposition and phagocyte activation participate in inflammatory reactions in the brain during the course of Alzheimer's disease. To further investigate the effects of A beta-phagocyte interaction, we examined the production of proinflammatory (IL-1beta, IL-6), chemotactic (MIP-1alpha, IP-10) and inhibitory (IL-1Ra, IL-10 and TGFbeta1) cytokines by cultured human monocytes and mouse microglial cells upon stimulation with A beta[25-35]. Northern blot analysis and specific immunoassays demonstrated that A beta[25-35] triggers mRNA expression and release of IL-1beta, IL-1Ra and MIP-1alpha but not of IL-6, IL-10, TGFbeta1 and IP-10 from human monocytes. Similar results were obtained by examining the production of IL-1beta, IL-6 and IL-10 from mouse microglial cells in the same experimental conditions. Taken together, these data indicate that A beta-phagocyte interaction can drive a different response towards cytokine production by monocytes and microglia, with a particular proinflammatory trend, and further support a role for A beta deposition as a triggering factor of inflammatory events in Alzheimer's disease.
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Affiliation(s)
- L Meda
- Institute of Neurology, Dino Ferrari Center, University of Milan, IRCCS Ospedale Maggiore Policlinico, Italy
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29
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Popa-Wagner A, Schröder E, Walker LC, Kessler C. beta-Amyloid precursor protein and ss-amyloid peptide immunoreactivity in the rat brain after middle cerebral artery occlusion: effect of age. Stroke 1998; 29:2196-202. [PMID: 9756603 DOI: 10.1161/01.str.29.10.2196] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Previous studies have shown that the ss-amyloid precursor protein (ssAPP) is upregulated after cerebral ischemia and that the ss-amyloid (Ass) fragment may be toxic to brain cells. Although stroke in humans usually afflicts the elderly, most experimental studies on the nature of cerebral ischemia have used young animals. To test the hypothesis that the upregulation and/or persistence of amyloidogenic proteins is exacerbated in aged rats after cerebral ischemic stroke, we studied the expression of ssAPP and its proteolytic product Ass in the brains of young and old rats 7 days after temporary cerebral ischemia. METHODS Focal cerebral ischemia was produced by reversible occlusion of the right middle cerebral artery in 3- and 20-month-old male Sprague-Dawley rats. After 1 week, brains were removed and immunostaining was performed for ssAPP, Ass, and ED1 for macrophages and glial fibrillary acidic protein (GFAP). RESULTS Histological staining revealed that the degree of necrotic cavitation in the infarct core was relatively less in aged rats than in young rats, suggesting a slower pace of degenerative change and/or tissue removal in older animals. ssAPP immunoreactivity was robustly increased, primarily in macrophage-like, ED1-positive cells in the infarct core and in the penumbra of both young and aged animals. Ass immunoreactivity was evident in GFAP-positive astrocytic somata and processes, and also in clusters of small spherical structures in the penumbra. These Ass-immunoreactive minispheres were more numerous in aged rats than in young rats. CONCLUSIONS The presence of ssAPP and Ass immunoreactivity in the infarct core and penumbra indicates that cerebral ischemia promotes conditions that are favorable to the focal accumulation of ssAPP and its proteolytic fragments, especially in the aged brain.
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Affiliation(s)
- A Popa-Wagner
- Department of Neurology, Division of Warner-Lambert, Ann Arbor, Mich
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30
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Abstract
The nervous system and peripheral tissues in mammals contain a large number of biologically active peptides and proteases that function as neurotransmitters or neuromodulators in the nervous system, as hormones or cellular mediators in peripheral tissue, and play a role in human neurological diseases. The existence and possible functional relevance of bradykinin and kallidin (the peptides), kallikreins (the proteolytic enzymes), and kininases (the peptidases) in neurophysiology and neuropathological states are discussed in this review. Tissue kallikrein, the major cellular kinin-generating enzyme, has been localised in various areas of the mammalian brain. Functionally, it may assist also in the normal turnover of brain proteins and the processing of peptide-hormones, neurotransmitters, and some of the nerve growth factors that are essential for normal neuronal function and synaptic transmission. A specific class of kininases, peptidases responsible for the rapid degradation of kinins, is considered to be identical to enkephalinase A. Additionally, kinins are known to mediate inflammation, a cardinal feature of which is pain, and the clearest evidence for a primary neuronal role exists so far in the activation by kinins of peripherally located nociceptive receptors on C-fibre terminals that transmit and modulate pain perception. Kinins are also important in vascular homeostasis, the release of excitatory amino acid neurotransmitters, and the modulation of cerebral cellular immunity. The two kinin receptors, B2 and B1, that modulate the cellular actions of kinins have been demonstrated in animal neural tissue, neural cells in culture, and various areas of the human brain. Their localisation in glial tissue and neural centres, important in the regulation of cardiovascular homeostasis and nociception, suggests that the kinin system may play a functional role in the nervous system.
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Affiliation(s)
- D M Raidoo
- Department of Physiology, Faculty of Medicine, University of Natal, Durban, South Africa
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31
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Johnston JA, Lannfelt L, Wiehager B, O'Neill C, Cowburn RF. Amyloid precursor protein heat shock response in lymphoblastoid cell lines bearing presenilin-1 mutations. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1362:183-92. [PMID: 9540849 DOI: 10.1016/s0925-4439(97)00074-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The amyloid precursor protein (APP) gene promoter contains a heat shock element. An abnormal APP heat shock response could increase accumulation of A beta, the APP metabolite found in Alzheimer's disease amyloid plaques. Since A beta production is affected by presenilin-1 (PS-1) mutations, we investigated whether basal APP levels or response to heat shock were altered in lymphoblastoid cell lines from 8 PS-1 mutation-bearers and 9 control members of Alzheimer's disease families. Lymphoblastoid cell lines were incubated at 42 degrees C for 35 min and allowed to recover at 37 degrees C for 1, 3, 8, 24 and 48 h. APP mRNA levels, quantified using RNA-RNA solution hybridisation, increased significantly at 1 and 3 h post-heat shock to between 123% and 163% of pre-heat shock (0 h) levels and returned to normal by 8 h. Semi-quantitative Western immunoblotting of cell lysates using the 22C11 antibody detected two major bands, migrating at approximately 145 and approximately 120 kDa. Band optical densities increased significantly at 3 h to approximately 155% of 0 h levels, following the increase in APP mRNA levels and showing a similar reversibility. APP mRNA and protein responses were comparable in the PS-1 mutation-bearing and control cell lines. This study shows that both APP mRNA and protein are induced in lymphoblastoid cell lines following heat shock and that this response is not affected by PS-1 mutations which are pathogenic for Alzheimer's disease.
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Affiliation(s)
- J A Johnston
- Karolinska Institute, Department of Clinical Neuroscience and Family Medicine, Novum KFC, Huddinge, Sweden.
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32
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Van Dyke K. The possible role of peroxynitrite in Alzheimer's disease: a simple hypothesis that could be tested more thoroughly. Med Hypotheses 1997; 48:375-80. [PMID: 9185121 DOI: 10.1016/s0306-9877(97)90031-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Alzheimer's disease is characterized by the development of a degenerative condition in the elderly, associated with dementia. Upon pathological examination, cerebral amyloid plaques are found which contain denatured protein or peptide material. The process of denaturation of protein requires the presence of excessive heat, organic solvents, or oxidizing acids (OA). It seems that only OA could produce these effects since the other two are not present in the disease. Macrophages can produce the anion of an oxidizing acid known as peroxynitrite (OONO). This material is formed from two free radical gases, namely superoxide anion [.O2]- and nitric oxide (.N = O). Although (OONO)- is very reactive (1000 times more oxidizing than hydrogen peroxide), its half life in solution is only 1 to 2 seconds. Therefore, when it oxidizes a substance (such as protein) peroxynitrite disappears. The brain contains cells called microglia which are produced from monocytes in the same way as other types of macrophages from the lung and liver etc. The macrophages from the lung (alveolar) and liver (Kupfer cells) produce large amounts of peroxynitrite when activated by particles (silica) or infectious agents (lipopolysaccharide or interferon). Microglia produce highly oxidizing substances as well, but no one has ever measured production of peroxynitrite from these cells. Assuming that microglia produce peroxynitrite, or other similar oxidants, anti-oxidant and anti-inflammatory drugs should be helpful in treatment of early forms of the disease. In addition, large doses of anti-oxidant vitamin C and vitamin E might be helpful to people with Alzheimer's disease.
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Affiliation(s)
- K Van Dyke
- Department of Pharmacology & Toxicology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown 26506, USA
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33
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Bullido MJ, Muñoz-Fernandez MA, Recuero M, Fresno M, Valdivieso F. Alzheimer's amyloid precursor protein is expressed on the surface of hematopoietic cells upon activation. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1313:54-62. [PMID: 8781550 DOI: 10.1016/0167-4889(96)00015-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A4-amyloid is the major component of senile plaques and neurofibrillary tangles found in the brain of patients suffering Alzheimer's disease. This 39-42 amino acid peptide is derived from a larger precursor protein (APP). Since APP gene encodes for a putative membrane protein, the study of APP expression at the cell surface may provide useful data for understanding its physiological function. In this report, we present data on APP expression, that was detected by APP specific mAbs in cells of the hematopoietic system. APP was weakly expressed on the cell surface of resting human lymphocytes and monocytes, but it could be induced to the surface of those cells upon stimulation. The cell activators capable of inducing APP membrane expression comprehended mitogenic lectins, calcium ionophores, phosphatase inhibitors, and anti mu-chain or anti-CD3 antibodies in B and T cells, respectively. Interestingly, phorbol esters were able to induce APP membrane expression in monocytic, but not in lymphoid cells. In contrast to lymphocytes and monocytes, granulocytes never expressed cell surface or cytoplasmic APP, even after the activation. The induction of membrane APP in response to lymphocyte activation signals, including antibodies to the antigen receptor of B and T cells, raises the possibility that APP might play the role of a cell surface receptor in the immune system.
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Affiliation(s)
- M J Bullido
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Spain
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34
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Eckert A, Förstl H, Zerfass R, Hartmann H, Müller WE. Lymphocytes and neutrophils as peripheral models to study the effect of beta-amyloid on cellular calcium signalling in Alzheimer's disease. Life Sci 1996; 59:499-510. [PMID: 8761338 DOI: 10.1016/0024-3205(96)00329-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
According to the calcium hypothesis of brain aging, disturbances of free intracellular calcium homeostasis ([Ca2+]i) play a key role in pathology of Alzheimer's disease (AD). Recent data from neuronal tissue culture support the contribution of the beta-amyloid peptide (beta A) to neurodegeneration in AD, probably by disruption of the intracellular Ca2+ regulation. On the basis of this premise, we used peripheral blood cells to examine the role of beta A on Ca2+ signalling, not only to obtain an experimental approach to investigate these effects of beta A in man, but also to search for AD-specific alterations of the effects of beta A on Ca2+ signalling. This approach is based on observations indicating that the phytohemagglutinin (PHA)-induced Ca2+ response in circulating human lymphocytes of healthy volunteers is affected by beta A and its fragment 25-35 in a fashion similar to its effects on central neurons, whereas we found no effect of beta A on receptor-activated Ca2+ response in neutrophils. Therefore, we used human blood lymphocytes as peripheral model systems to search directly for AD-related abnormalities of Ca2+ regulation, for alterations of beta A effects on Ca2+ signalling and on membrane fluidity, and for possible changes of potassium channels. In accordance with our data in neutrophils, we were unable to identify any relevant change of the PHA-induced Ca2+ elevations in lymphocytes, which is not supporting the assumption of general alterations of cellular Ca2+ regulation in AD. On the other hand, the amplifying effect of beta A on Ca2+ signalling was significantly reduced in lymphocytes from AD patients. Moreover, Ca2+ responses to beta A25-35 were not different between early- and late-onset AD patients. Our findings indicate that the sensitivity of the lymphocyte for the effects of beta A is reduced in a high percentage of patients with probable or possible AD. As possible explanation we observed a similar reduction of the sensitivity of the lymphocyte membrane for the fluidity-decreasing properties of beta A. Finally, the inhibition of the PHA-induced Ca2+ response by tetraethylammonium (TEA) was lower in the AD group compared to aged controls. This could suggest the presence of a K+ channel dysfunction on AD lymphocytes, as it has been shown on skin fibroblasts of AD patients.
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Affiliation(s)
- A Eckert
- Department of Psychopharmacology, Central Institute of Mental Health, Mannheim, Germany
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35
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Sudoh S, Kawakami H, Nakamura S. Serum deprivation alters the expression and the splicing at exons 7, 8 and 15 of the beta-amyloid precursor protein in the C6 glioma cell line. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1996; 39:12-22. [PMID: 8804709 DOI: 10.1016/0169-328x(95)00348-v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amyloid deposition characterizes the pathological lesions of Alzheimer's disease. We investigated the effect of serum deprivation on the regulation of beta-amyloid precursor protein (APP) mRNA expression in C6 glioma cells. Serum deprivation increased APP mRNA levels approximately 4-fold over controls. This increase was accompanied by changes in the pattern of alternative splicing, including the novel alternatively spliced site at exon 15. The proportion of isoforms containing exons 7 and 8 significantly increased from 61% to 68%, while isoforms lacking these exons decreased from 14% to 8%. The proportion of leukocyte-derived APP, which is a novel alternatively spliced isoform lacking exon 15, significantly increased from 19% to 40%. Among the six major isoforms produced by the two independent splicing sites, L-APP752 which contains exons 7 and 8, but lacks exon 15, increased the most (approximately 10-fold). Our findings provide evidence linking APP expression to alterations in alternative splicing at exon 15. These results demonstrate that in glial cells, APP mRNA regulation involves the alteration in alternative splicing at exons 7, 8 and 15, suggesting that not only increased expression but also an imbalance in the relative abundance of the six APP isoforms in stressed condition might affect the amyloidogenesis in Alzheimer's disease.
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Affiliation(s)
- S Sudoh
- Third Department of Internal Medicine, Hiroshima University School of Medicine, Japan
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36
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Mark RJ, Blanc EM, Mattson MP. Amyloid beta-peptide and oxidative cellular injury in Alzheimer's disease. Mol Neurobiol 1996; 12:211-24. [PMID: 8884749 DOI: 10.1007/bf02755589] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Alzheimer's disease is a progressive neurodegenerative disorder that affects primarily learning and memory functions. There is significant neuronal loss and impairment of metabolic functioning in the temporal lobe, an area believed to be crucial for learning and memory tasks. Aggregated deposits of amyloid beta-peptide may have a causative role in the development and progression of AD. We review the cellular actions of A beta and how they can contribute to the cytotoxicity observed in AD. A beta causes plasma membrane lipid peroxidation, impairment of ion-motive ATPases, glutamate uptake, uncoupling of a G-protein linked receptor, and generation of reactive oxygen species. These effects contribute to the loss of intracellular calcium homeostasis reported in cultured neurons. Many cell types other than neurons show alterations in the Alzheimer's brain. The effects of A beta on these cell types is also reviewed.
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Affiliation(s)
- R J Mark
- Sanders-Brown Research Center on Aging, University of Kentucky, Lexington 40536, USA
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37
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Greenberg BD, Savage MJ, Howland DS, Ali SM, Siedlak SL, Perry G, Siman R, Scott RW. APP transgenesis: approaches toward the development of animal models for Alzheimer disease neuropathology. Neurobiol Aging 1996; 17:153-71. [PMID: 8744397 DOI: 10.1016/0197-4580(96)00001-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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38
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Premkumar DR, Kalaria RN. Altered expression of amyloid beta precursor mRNAs in cerebral vessels, meninges, and choroid plexus in Alzheimer's disease. Ann N Y Acad Sci 1996; 777:288-92. [PMID: 8624100 DOI: 10.1111/j.1749-6632.1996.tb34434.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Altered tissue-specific processing or production of the amyloid precursor protein (APP) is thought to be central to amyloid deposition in cerebrovascular and the neocortical tissues in Alzheimer's disease (AD). We demonstrate that A beta peptide(s) is readily detectable and increased in cerebral vessels, meninges and choroid plexus obtained at autopsy from AD subjects compared to age-matched controls. Using the reverse transcription (RT)-polymerase chain reaction (PCR), we further found that A beta transcripts encoding the A beta sequence in all forms of APP containing exons 16 and 17 (of APP770) were significantly increased in vessel samples in AD subjects. This was also evident in the neocortical samples and not related to pre-mortem factors or postmortem interval. It is possible that the increased A beta mRNAs reflect enhanced expression of the L-APP isoform (APP770 without exon 15) expressed in leukocytes and glia alike. We also found evidence for changed proportions of APP 770, 756 and 695 mRNAs in cerebral vessel samples from AD subjects compared to controls. Whereas APP770 and APP751, the predominant forms, were significantly decreased, APP695 transcript was increased in vessel samples from AD subjects. Such changes were not evident in neocortical samples from the same subjects. These observations suggest tissue-specific changes in expression of APP isoforms implicating one of the mechanisms for increased accumulation of A beta in cerebrovascular tissues in AD.
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Affiliation(s)
- D R Premkumar
- Department of Neurology, Case Western Reserve University, Cleveland, Ohio 44106, USA
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39
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Beyreuther K, Multhaup G, Mönning U, Sandbrink R, Beher D, Hesse L, Small DH, Masters CL. Regulation of APP expression, biogenesis and metabolism by extracellular matrix and cytokines. Ann N Y Acad Sci 1996; 777:74-6. [PMID: 8624129 DOI: 10.1111/j.1749-6632.1996.tb34403.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have identified and characterized the ligand binding properties of the Alzheimer's disease (AD) beta A4 amyloid protein precursor (APP), mapped the APP ligand binding sites and analyzed the regulation of APP expression, biogenesis and metabolism by components of the extracellular matrix (ECM) and cytokines.
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Affiliation(s)
- K Beyreuther
- ZMBH, Center for Molecular Biology, University of Heidelberg, Germany.
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40
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Ebstein RP, Nemanov L, Lubarski G, Dano M, Trevis T, Korczyn AD. Changes in expression of lymphocyte amyloid precursor protein mRNA isoforms in normal aging and Alzheimer's disease. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1996; 35:260-8. [PMID: 8717362 DOI: 10.1016/0169-328x(95)00227-j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We measured, by employing a quantitative reverse-transcriptase PCR procedure, the relative (to beta-actin) levels of amyloid precursor protein APP751 and APP770 mRNA isoforms in lymphocytes obtained from 64 cognitively intact subjects ranging in ages from 20 to 91 years and in 19 patients with sporadic Alzheimer's disease. A positive correlation was observed between the relative lymphocyte APP751 mRNA levels and subject age for the cognitively intact cohort. No difference in lymphocyte APP751 mRNA levels was observed between Alzheimer's disease patients and their age-matched controls (> 55 years of age). However, the ratio of lymphocyte APP751:APP770 mRNA levels was significantly lower in Alzheimer's disease subjects compared to the > 55-year-old cohort. This decreased ratio is most likely due to an average 31% increase in the lymphocyte APP770 isoform in Alzheimer's disease patients compared to 12% in the > 55-year-old cognitively intact group. Marked individual differences in amount of APP mRNA isoforms were encountered among all the subject groups and in the < or = 55-year-old cohort, a 10-fold variation in individual APP751 mRNA levels was observed. The relevance of these findings in lymphocytes to the pathogenesis of Alzheimer's disease is discussed.
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Affiliation(s)
- R P Ebstein
- Shapiro Molecular Neurobiology Laboratory, S. Herzog Memorial Hospital, Jerusalem 91351, Israel
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41
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Grilli M, Ribola M, Alberici A, Valerio A, Memo M, Spano P. Identification and characterization of a kappa B/Rel binding site in the regulatory region of the amyloid precursor protein gene. J Biol Chem 1995; 270:26774-7. [PMID: 7592914 DOI: 10.1074/jbc.270.45.26774] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Several observations support the hypothesis that pathogenetic mechanisms of beta amyloid formation in Alzheimer's disease may involve alterations in amyloid precursor protein (APP) gene expression. In this regard, molecular dissection of the APP gene transcriptional regulation is of primary importance. We report evidence that members of the family of transcription factors NF kappa B/Rel can specifically recognize two identical sequences located in the 5'-regulatory region of APP. These sequences, which we refer to as APP kappa B sites, interact preferentially with p50-containing members of the family. In particular, p50 homodimers and p50/p65 and p50/c-Rel heterodimers act as transcriptional activators at the APP kappa B site. Finally, the nuclear complex specifically binding to the APP kappa B sites proves to be an integral part of neurons and lymphocytes.
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Affiliation(s)
- M Grilli
- Department of Biomedical Sciences and Biotechnologies, School of Medicine, University of Brescia, Italy
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42
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Gilbert RE, Cox A, Dziadek M, Cooper ME, Jerums G. Extracellular matrix and its interactions in the diabetic kidney: a molecular biological approach. J Diabetes Complications 1995; 9:252-4. [PMID: 8573740 DOI: 10.1016/1056-8727(95)80015-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Increased extracellular matrix (ECM) is the ultrastructural hallmark of diabetic microangiopathy. Its accumulation within the kidney is directly linked to the clinical manifestations of diabetic nephropathy, namely proteinuria and declining renal function. The pathogenesis of ECM changes in diabetes is not well understood, but is likely to involve interaction between cells, growth factors, structural proteins, and cell receptors for these molecules. Molecular biological techniques may offer the necessary tools for gaining insight into the pathogenetic processes that eventually lead to renal failure in diabetes.
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Affiliation(s)
- R E Gilbert
- Endocrinology Unit Austin Hospital, Victoria, Australia
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43
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Gehrmann J, Banati RB, Cuzner ML, Kreutzberg GW, Newcombe J. Amyloid precursor protein (APP) expression in multiple sclerosis lesions. Glia 1995; 15:141-51. [PMID: 8567065 DOI: 10.1002/glia.440150206] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The amyloid precursor protein (APP) is rapidly induced in reactive glial cells in response to several pathological stimuli including inflammation. In the present study, observations previously made in animal models of autoimmune central nervous system inflammation have been extended to the analysis of multiple sclerosis (MS) lesions. A total of thirty fresh-frozen tissue blocks from six histopathologically normal control and six MS cases have been examined immunocytochemically with monoclonal antibodies directed against either C- or N-terminal epitopes of APP. Histopathological evaluation of disease progression was based on hematoxylin-eosin and oil red O staining and immunocytochemistry for T cells, macrophages/microglia, astrocytes, and oligodendrocytes. In control cases, APP immunoreactivity was generally low and confined to blood vessel walls, oligodendrocytes in white, and neurons in grey matter. In actively demyelinating plaques, however, levels of APP immunoreactivity were high, localised on T lymphocytes, foamy macrophages, activated microglia, and reactive astrocytes including astrocytic processes. In more chronic lesions, levels of APP immunoreactivity were generally lower than in acute lesions, mainly found on reactive astrocytes, their processes and a few macrophages/microglia depending on the stage of plaque development. In addition, a few 14E-positive oligodendrocytes and, moreover, numerous axons exhibited APP immunoreactivity, which was particularly pronounced with anti-C-terminal antibodies. These results demonstrate that APP is induced on reactive glial cells but also on T lymphocytes during demyelination. The extent of APP expression appears to be correlated to histopathological lesion development and thus suggests that APP detection serves as a sensitive marker for disease progression in MS.
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Affiliation(s)
- J Gehrmann
- Department of Pathology, University Hospital, Zurich, Switzerland
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44
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Gehrmann J, Banati RB, Wiessner C, Hossmann KA, Kreutzberg GW. Reactive microglia in cerebral ischaemia: an early mediator of tissue damage? Neuropathol Appl Neurobiol 1995; 21:277-89. [PMID: 7494596 DOI: 10.1111/j.1365-2990.1995.tb01062.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Microglial cell activation is a rapidly occurring cellular response to cerebral ischaemia. Microglia proliferate, are recruited to the site of lesion, upregulate the expression of several surface molecules including major histocompatibility complex class I and II antigens, complement receptor and the amyloid precursor protein (APP) as well as newly expressed cytokines, e.g. interleukin-1 and transforming growth factor beta 1. The ischaemia-induced production of APP may contribute to amyloid deposition in the aged brain under conditions of hypofusion. Ultrastructurally, microglia transform into phagocytes removing necrotic neurons but still respecting the integrity of eventually surviving neurons even in the close vicinity of necrotic neurons. Microglial activation starts within a few minutes after ischaemia and thus precedes the morphologically detectable neuronal damage. It additionally involves a transient generalized response within the first 24 hours post-ischaemia even at sites without eventual neuronal cell death. In functional terms, the microglial reaction appears to be a double-edged sword in ischaemia. Activated microglia may exert a cytotoxic effector function by releasing reactive oxygen species, nitric oxide, proteinases or inflammatory cytokines. All of these cytotoxic compounds may cause bystander damage following ischaemia. Pharmacological suppression of microglial activation after ischaemia has accordingly attenuated the extent of cell death and tissue damage. However, activated microglia support tissue repair by secreting factors such as transforming growth factor beta 1 which may limit tissue damage as well as suppress astroglial scar formation. In line with ultrastructural observations microglial activation in ischaemia is a strictly controlled event. By secreting cytokines and growth factors activated microglia most likely serve seemingly opposed functions in ischaemia, i.e. maintenance as well as removal of injured neurons. Post-ischaemic pharmacological modulation of microglial intervention in the cascade of events that lead to neuronal necrosis may help to improve the structural and functional outcome following CNS ischaemia.
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Affiliation(s)
- J Gehrmann
- Department of Pathology, University Hospital, Zürich, Switzerland
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45
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Banati RB, Gehrmann J, Wiessner C, Hossmann KA, Kreutzberg GW. Glial expression of the beta-amyloid precursor protein (APP) in global ischemia. J Cereb Blood Flow Metab 1995; 15:647-54. [PMID: 7790414 DOI: 10.1038/jcbfm.1995.80] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The beta-amyloid precursor protein (APP) bears characteristics of an acute-phase protein and therefore is likely to be involved in the glial response to brain injury. In the brain, APP is rapidly synthesized by activated glial cells in response to comparatively mild neuronal lesions, e.g., a remote peripheral nerve injury. Perfusion deficits in the brain result largely in neuronal necrosis and are a common condition in elderly patients. This neuronal necrosis is accompanied by a pronounced reaction of astrocytes and microglia, which can also be observed in animal models. We have therefore studied in the rat, immunocytochemically, the induction of APP after 30 min of global ischemia caused by four-vessel occlusion. The postischemic brain injuries were examined at survival times from 12 h to 7 days. From day 3 onward, APP immunoreactivity was strongly induced in the CA1 and CA4 regions of the rat dorsal hippocampus as well as in the dorsolateral striatum. In these areas, the majority of APP-immunoreactive cells were reactive glial fibrillary acidic protein (GFAP)-positive astrocytes, as shown by double-immunofluorescence labeling for GFAP and APP. Additionally, small ramified cells, most likely activated microglia, expressed APP immunoreactivity. In contrast, in the parietal cortex, APP immunoreactivity occurred focally in clusters of activated microglia rather than in astrocytes, as demonstrated by double-immunofluorescence labeling for APP and the microglia-binding lectin Griffonia simplicifolia isolectin B4. In conclusion, following global ischemia, APP is induced in reactive glial cells with spatial differences in the distribution pattern of APP induction in astrocytes and microglia.
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Affiliation(s)
- R B Banati
- Department of Neuromorphology, Max Planck Institute of Psychiatry, Martinsried, Germany
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Banati RB, Gehrmann J, Lannes-Vieira J, Wekerle H, Kreutzberg GW. Inflammatory reaction in experimental autoimmune encephalomyelitis (EAE) is accompanied by a microglial expression of the beta A4-amyloid precursor protein (APP). Glia 1995; 14:209-15. [PMID: 7591032 DOI: 10.1002/glia.440140306] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuropathological studies of the amyloid depositions and senile plaques in the brains of elderly patients or patients diagnosed with Alzheimer's disease reveal the conspicuous presence of numerous proteins which are usually expressed during reactions of the immune system. This has led to speculations that the pathomechanism of neurodegenerative diseases might involve inflammatory processes. These considerations constitute the theoretical basis for therapeutic intervention with antiinflammatory drugs in neurodegenerative diseases. Here, we show that the beta A4-amyloid precursor (APP) is rapidly induced in microglia in a model of experimental autoimmune encephalomyelitis (EAE). Using specific monoclonal antibodies against APP, the first glial cells newly expressing APP immunoreactivity were found at an early preclinical stage, i.e., 24 h after T-cell transfer. At the peak of clinical disease (6 days after T-cell transfer), numerous characteristically ramified cells were strongly positive for APP. Based on morphology and double-labeling, most of the de novo APP-expressing cells were identified as microglia. Additionally, APP-immunoreactive round cells were detected in and around perivascular infiltrates. Reflecting the course of the clinical disease, the induction of APP immunoreactivity terminated in the postclinical stage, i.e., 14 days after T-cell transfer. These results support earlier work demonstrating that microglia can rapidly de novo synthesise APP not only in response to direct nerve injury (Banati et al: Glia 9:199, 1993a) but also in immune-mediated disease. Apart from its possible therapeutic relevance, such a production of APP--reminiscent of an acute phase protein-suggests a role of APP in immune and repair mechanisms of the central nervous system.
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Affiliation(s)
- R B Banati
- Department of Neuromorphology, Max-Planck-Institute for Psychiatry, Martinsried, Germany
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Matsumoto A, Matsumoto R, Fujiwara Y. Molecular cloning of human cDNA with a sequence highly similar to that of the dihydrofolate reductase gene in brain libraries derived from Alzheimer's disease patients. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 230:337-43. [PMID: 7601120 DOI: 10.1111/j.1432-1033.1995.0337i.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A polyclonal antibody was raised against a serine protease purified from the extracellular fluid of familial Alzheimer's disease lymphoblastoid cells. Using this antibody, a cDNA library from familial Alzheimer's disease cells and two cDNA libraries from the brains of two Alzheimer's disease patients were screened independently. The familial Alzheimer's disease protein 1 (FADP1) cDNA clones isolated from these three libraries were subjected to DNA sequence analysis. The nucleotide sequence of FADP1 cDNA is highly similar to the 5' portion of the human dihydrofolate reductase (DHFR) gene, however, the sequence corresponding to exon 1 of the DHFR gene is completely disrupted and contains a 247-bp DNA insert with a sequence unique to FADP1. Moreover, FADP1 cDNA harbours a large open reading frame, including the unique insert, which has the potential to code an approximately 50-kDa protein. The deduced amino acid sequence of this protein contains 12 cysteine residues potentially involved in six disulfide bonds, a proline-rich segment and a hydrophobic segment. Northern-blot analysis with the unique insert DNA probe verified that FADP1 protein is expressed in both lymphoblastoid and brain cells derived from Alzheimer's disease patients.
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Affiliation(s)
- A Matsumoto
- Department of Radiation Biophysics and Genetics, Kobe University School of Medicine, Japan
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Mönning U, Sandbrink R, Weidemann A, Banati RB, Masters CL, Beyreuther K. Extracellular matrix influences the biogenesis of amyloid precursor protein in microglial cells. J Biol Chem 1995; 270:7104-10. [PMID: 7706247 DOI: 10.1074/jbc.270.13.7104] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
During axotomy studies, we discovered that the beta A4-amyloid precursor protein (APP) participates in immune responses of the central nervous system. Since microglia constitute the main immune effector cell population of this response, we used the murine microglial cell line BV-2 to analyze immune response-related APP expression. We show that interaction of microglia with the extracellular environment, particularly components of the extracellular matrix, affects APP secretion as well as intracellular APP biogenesis and catabolism. Fibronectin enhanced APP secretion and decreased the level of cellular mature transmembrane APP, whereas laminin and collagen caused a decrease in secretion and an accumulation of cellular mature APP and APP fragments. Our results demonstrate that APP plays a fundamental role in the regulation of microglial mobility, i.e. migration, initial target recognition, and binding. The decrease in APP secretion and the concomitant increase in cellular mature APP were accompanied by an accumulation of C-terminal APP fragments. Enrichment of APP and APP fragments is assumedly based on inhibition of catabolic processes that is caused by a disorganization of the actin microfilament network. These observations provide evidence that microglia, which are closely associated with certain amyloid deposits in the brain of Alzheimer patients, can play a key role in initial events of amyloidogenesis by initiating accumulation of APP and also of amyloidogenic APP fragments in response to physiological changes upon brain injury.
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Affiliation(s)
- U Mönning
- Center for Molecular Biology Heidelberg, University of Heidelberg, Federal Republic of Germany
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Okamoto T, Takeda S, Murayama Y, Ogata E, Nishimoto I. Ligand-dependent G protein coupling function of amyloid transmembrane precursor. J Biol Chem 1995; 270:4205-8. [PMID: 7876177 DOI: 10.1074/jbc.270.9.4205] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Amyloid precursor protein (APP), a transmembrane precursor of beta-amyloid, possesses a function whereby it associates with G(o) through its cytoplasmic His657-Lys676. Here we demonstrate that APP has a receptor function. In phospholipid vesicles consisting of baculovirally made APP695 and brain trimeric G(o), 22C11, a monoclonal antibody against the extracellular domain of APP, increased GTP gamma S binding and the turnover number of GTPase of G(o) without affecting its intrinsic GTPase activity. This effect of 22C11 was specific among various antibodies and was observed neither in G(o) vesicles nor in APP695/Gi2 vesicles. In APP695/G(o) vesicles, synthetic APP66-81, the epitope of 22C11, competitively antagonized the action of 22C11. Monoclonal antibody against APP657-676, the G(o) binding domain of APP695, specifically blocked 22C11-dependent activation of G(o). Therefore, APP has a potential receptor function whereby it specifically activates G(o) in a ligand-dependent and ligand-specific manner.
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Affiliation(s)
- T Okamoto
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown
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Töpper R, Gehrmann J, Banati R, Schwarz M, Block F, Noth J, Kreutzberg GW. Rapid appearance of beta-amyloid precursor protein immunoreactivity in glial cells following excitotoxic brain injury. Acta Neuropathol 1995; 89:23-8. [PMID: 7709727 DOI: 10.1007/bf00294255] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Clinical and experimental data have indicated an up-regulation of amyloid precursor protein (APP) after various types of CNS injury. In the present study the cellular source of lesion-induced APP has been investigated in a neurotoxic CNS model. Quinolinic acid injection into the striatum results in neuronal degeneration, while glial cells survive. APP immunoreactivity was detected in glial cells starting at postoperative day 3 and persisted until day 21, the last time point studied. Double immunocytochemistry identified the majority of APP-immunoreactive cells as glial fibrillary acidic protein-immunoreactive astrocytes. There was no evidence of amyloid fibril deposition during this time. It is concluded that following excitotoxic neuronal degneration APP is mainly produced by reactive astrocytes in the lesioned area.
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Affiliation(s)
- R Töpper
- Max-Planck-Institute of Psychiatry, Department of Neuromorphology, Martinsried, Germany
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