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Buawangpong N, Pinyopornpanish K, Phrommintikul A, Chindapan N, Devahastin S, Chattipakorn N, Chattipakorn SC. Increased plasma trimethylamine- N-oxide levels are associated with mild cognitive impairment in high cardiovascular risk elderly population. Food Funct 2022; 13:10013-10022. [PMID: 36069253 DOI: 10.1039/d2fo02021a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Trimethylamine-N-oxide (TMAO) has been shown to be associated with cardiovascular (CV) disease and cognitive impairment. The association between early stages of cognitive impairment and TMAO in a high CV risk population has not been previously investigated. This study aimed to investigate the association between the plasma TMAO level and cognitive function in a population with a high risk of CV disease. Participants at a high risk of CV were included. The cognition was evaluated using the Montreal Cognitive Assessment. A score lower than 25 out of 30 was used to indicate mild cognitive impairment (MCI). Blood samples of all participants (n = 233) were collected to measure the plasma levels of TMAO and other metabolic parameters, including fasting blood sugar and lipid profiles. Logistic regression was used to evaluate the association between MCI and high plasma TMAO levels, adjusted for confounding factors. Of 233 patients, the mean age of patients in this study was 64 years old (SD 8.4). The median TMAO level was 4.31 μM (IQR 3.95). The high TMAO level was an independent risk factor of MCI (aOR 2.36, 95% CI 1.02 to 5.47; p 0.046), when adjusted for age, gender, health care service scheme, smoking history, metabolic syndrome, and history of established CV events. The high TMAO level was associated with MCI, after adjustment for potential confounding factors. These findings demonstrate that plasma TMAO levels can serve for target prediction as an independent risk factor for MCI in this population.
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Affiliation(s)
- Nida Buawangpong
- Department of Family Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 50200
| | - Kanokporn Pinyopornpanish
- Department of Family Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 50200
| | - Arintaya Phrommintikul
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 50200
| | - Nathamol Chindapan
- Department of Food Technology, Faculty of Science, Siam University, Bangkok, Thailand 10160
| | - Sakamon Devahastin
- Advanced Food Processsing Rsesearch Laboratory, Department of Food Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok, Thailand 10140.,The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, Thailand 10300
| | - Nipon Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 50200. .,Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 50200.,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand 50200
| | - Siriporn C Chattipakorn
- Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand 50200. .,Center of Excellence in Cardiac Electrophysiology Research, Chiang Mai University, Chiang Mai, Thailand 50200.,Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand 50200
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Lanz M, Janeiro MH, Milagro FI, Puerta E, Ludwig IA, Pineda-Lucena A, Ramírez MJ, Solas M. Trimethylamine N-Oxide (TMAO) drives insulin resistance and cognitive deficiencies in a senescence accelerated mouse model. Mech Ageing Dev 2022; 204:111668. [PMID: 35341897 DOI: 10.1016/j.mad.2022.111668] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/09/2022] [Accepted: 03/22/2022] [Indexed: 12/20/2022]
Abstract
It has been established that ageing is the major risk factor for cognitive deficiency and it is becoming increasingly evident that insulin resistance is another factor. Biological plausibility for a link between insulin resistance and dementia is relevant for understanding disease etiology, and to form bases for prevention efforts to decrease disease burden. In the present study, peripheral and central insulin resistance was found in SAMP8 mice (aging mouse model) accompanied by cognitive deficiencies. Furthermore, a marked peripheral inflammatory state was observed in SAMP8 mice, followed by neuroinflammation that could be due to a higher cytokine leaking into the brain across an aging-disrupted blood brain barrier. Moreover, aging-induced gut dysbiosis produces higher TMAO that could also contribute to the peripheral and central inflammatory tone as well as to the cognitive deficiencies observed in SAMP8 mice. All those alterations were reversed by DMB, a treatment that decreases TMAO levels. Data obtained from this project suggest that microbial dysbiosis and increased TMAO secretion could be a key link between aging, insulin resistance and dementia. Thus, pharmacological intervention that leads to decreased TMAO levels, such as DMB, could open a new avenue for the future treatment of neurodegenerative diseases.
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Affiliation(s)
- María Lanz
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain
| | - Manuel H Janeiro
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain; IdISNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Fermin I Milagro
- IdISNA, Navarra Institute for Health Research, Pamplona, Spain; Department of Nutrition, Food Science and Physiology, Centre for Nutrition Research, University of Navarra, Pamplona, Spain; CIBERobn, CIBER Fisiopatología de Obesidad y Nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - Elena Puerta
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain; IdISNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Iziar A Ludwig
- Program of Molecular Therapeutics, Center for Applied Medical Research (CIMA), Universidad de Navarra, Avda. Pío XII 55, E-31008 Pamplona, Spain
| | - Antonio Pineda-Lucena
- Program of Molecular Therapeutics, Center for Applied Medical Research (CIMA), Universidad de Navarra, Avda. Pío XII 55, E-31008 Pamplona, Spain
| | - María J Ramírez
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain; IdISNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Maite Solas
- Department of Pharmacology and Toxicology, University of Navarra, Pamplona, Spain; IdISNA, Navarra Institute for Health Research, Pamplona, Spain.
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Martín‐Segura A, Ahmed T, Casadomé‐Perales Á, Palomares‐Perez I, Palomer E, Kerstens A, Munck S, Balschun D, Dotti CG. Age-associated cholesterol reduction triggers brain insulin resistance by facilitating ligand-independent receptor activation and pathway desensitization. Aging Cell 2019; 18:e12932. [PMID: 30884121 PMCID: PMC6516156 DOI: 10.1111/acel.12932] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/30/2019] [Accepted: 02/01/2019] [Indexed: 01/08/2023] Open
Abstract
In the brain, insulin plays an important role in cognitive processes. During aging, these faculties decline, as does insulin signaling. The mechanism behind this last phenomenon is unclear. In recent studies, we reported that the mild and gradual loss of cholesterol in the synaptic fraction of hippocampal neurons during aging leads to a decrease in synaptic plasticity evoked by glutamate receptor activation and also by receptor tyrosine kinase (RTK) signaling. As insulin and insulin growth factor activity are dependent on tyrosine kinase receptors, we investigated whether the constitutive loss of brain cholesterol is also involved in the decay of insulin function with age. Using long‐term depression (LTD) induced by application of insulin to hippocampal slices as a read‐out, we found that the decline in insulin function during aging could be monitored as a progressive impairment of insulin‐LTD. The application of a cholesterol inclusion complex, which donates cholesterol to the membrane and increases membrane cholesterol levels, rescued the insulin signaling deficit and insulin‐LTD. In contrast, extraction of cholesterol from hippocampal neurons of adult mice produced the opposite effect. Furthermore, in vivo inhibition of Cyp46A1, an enzyme involved in brain cholesterol loss with age, improved insulin signaling. Fluorescence resonance energy transfer (FRET) experiments pointed to a change in receptor conformation by reduced membrane cholesterol, favoring ligand‐independent autophosphorylation. Together, these results indicate that changes in membrane fluidity of brain cells during aging play a key role in the decay of synaptic plasticity and cognition that occurs at this late stage of life.
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Affiliation(s)
- Adrián Martín‐Segura
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa CSIC/UAM Madrid Spain
- Department of Developmental and Molecular Biology Albert Einstein College of Medicine Bronx New York
| | - Tariq Ahmed
- Faculty of Psychology & Educational Sciences University of Leuven Leuven Belgium
- Neurological Disorders Research Center QBRI‐HBKU Doha Qatar
| | - Álvaro Casadomé‐Perales
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa CSIC/UAM Madrid Spain
| | - Irene Palomares‐Perez
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa CSIC/UAM Madrid Spain
| | - Ernest Palomer
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa CSIC/UAM Madrid Spain
- Cell & Developmental Biology Department University College London London UK
| | - Axelle Kerstens
- Department of Neuroscience, VIB Center for Brain and Disease Research University of Leuven Leuven Belgium
| | - Sebastian Munck
- Department of Neuroscience, VIB Center for Brain and Disease Research University of Leuven Leuven Belgium
| | - Detlef Balschun
- Faculty of Psychology & Educational Sciences University of Leuven Leuven Belgium
| | - Carlos G. Dotti
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa CSIC/UAM Madrid Spain
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Sherzai AZ, Shaheen M, Yu JJ, Talbot K, Sherzai D. Insulin resistance and cognitive test performance in elderly adults: National health and nutrition examination survey (NHANES). J Neurol Sci 2018; 388:97-102. [DOI: 10.1016/j.jns.2017.11.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/15/2017] [Accepted: 11/22/2017] [Indexed: 01/18/2023]
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5
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Pitt J, Wilcox KC, Tortelli V, Diniz LP, Oliveira MS, Dobbins C, Yu XW, Nandamuri S, Gomes FCA, DiNunno N, Viola KL, De Felice FG, Ferreira ST, Klein WL. Neuroprotective astrocyte-derived insulin/insulin-like growth factor 1 stimulates endocytic processing and extracellular release of neuron-bound Aβ oligomers. Mol Biol Cell 2017; 28:2623-2636. [PMID: 28963439 PMCID: PMC5620371 DOI: 10.1091/mbc.e17-06-0416] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/31/2017] [Indexed: 12/19/2022] Open
Abstract
Synaptopathy underlying memory deficits in Alzheimer's disease (AD) is increasingly thought to be instigated by toxic oligomers of the amyloid beta peptide (AβOs). Given the long latency and incomplete penetrance of AD dementia with respect to Aβ pathology, we hypothesized that factors present in the CNS may physiologically protect neurons from the deleterious impact of AβOs. Here we employed physically separated neuron-astrocyte cocultures to investigate potential non-cell autonomous neuroprotective factors influencing AβO toxicity. Neurons cultivated in the absence of an astrocyte feeder layer showed abundant AβO binding to dendritic processes and associated synapse deterioration. In contrast, neurons in the presence of astrocytes showed markedly reduced AβO binding and synaptopathy. Results identified the protective factors released by astrocytes as insulin and insulin-like growth factor-1 (IGF1). The protective mechanism involved release of newly bound AβOs into the extracellular medium dependent upon trafficking that was sensitive to exosome pathway inhibitors. Delaying insulin treatment led to AβO binding that was no longer releasable. The neuroprotective potential of astrocytes was itself sensitive to chronic AβO exposure, which reduced insulin/IGF1 expression. Our findings support the idea that physiological protection against synaptotoxic AβOs can be mediated by astrocyte-derived insulin/IGF1, but that this protection itself is vulnerable to AβO buildup.
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Affiliation(s)
- Jason Pitt
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Kyle C Wilcox
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Vanessa Tortelli
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Luan Pereira Diniz
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Maira S Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Cassandra Dobbins
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Xiao-Wen Yu
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Sathwik Nandamuri
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Flávia C A Gomes
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Nadia DiNunno
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Kirsten L Viola
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil.,Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - William L Klein
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
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6
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Ribe EM, Lovestone S. Insulin signalling in Alzheimer's disease and diabetes: from epidemiology to molecular links. J Intern Med 2016; 280:430-442. [PMID: 27739227 DOI: 10.1111/joim.12534] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
As populations across the world both age and become more obese, the numbers of individuals with Alzheimer's disease and diabetes are increasing; posing enormous challenges for society and consequently becoming priorities for governments and global organizations. These issues, an ageing population at risk of neurodegenerative diseases such as Alzheimer's disease and an increasingly obese population at risk of metabolic alterations such as type 2 diabetes, are usually considered as independent conditions, but increasing evidence from both epidemiological and molecular studies link these disorders. The aim of this review was to highlight these multifactorial links. We will discuss the impact of direct links between insulin and IGF-1 signalling and the Alzheimer's disease-associated pathological events as well as the impact of other processes such as inflammation, oxidative stress and mitochondrial dysfunction either common to both conditions or perhaps responsible for a mechanistic link between metabolic and neurodegenerative disease. An understanding of such associations might be of importance not only in the understanding of disease mechanisms but also in the search for novel therapeutic options.
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Affiliation(s)
- E M Ribe
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, UK
| | - S Lovestone
- Department of Psychiatry, Warneford Hospital, University of Oxford, Oxford, UK.
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7
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Ma L, Feng M, Qian Y, Yang W, Liu J, Han R, Zhu H, Li Y. Insulin resistance is an important risk factor for cognitive impairment in elderly patients with primary hypertension. Yonsei Med J 2015; 56:89-94. [PMID: 25510751 PMCID: PMC4276782 DOI: 10.3349/ymj.2015.56.1.89] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
PURPOSE Insulin resistance plays a role in the development of dementia and hypertension. We investigated a possible relationship between cognitive impairment and insulin resistance in elderly Chinese patients with primary hypertension. MATERIALS AND METHODS One hundred and thirty-two hypertensive elderly patients (>60 years) were enrolled in this study, and assigned into either the cognitive impairment group (n=61) or the normal cognitive group (n=71). Gender, age, education, body mass index (BMI), waist hip ratio (WHR), total cholesterol (TC), triglyceride (TG), C-reactive protein (CRP), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), creatinine (Cr), fasting plasma glucose (FPG), fasting insulin (FINS), homeostasis model of assessment for insulin resistance index (HOMA-IR), systolic blood pressure, diastolic blood pressure, smoking history, atherosclerosis and the proportion of uncontrolled hypertension were compared between the two groups. Multi-factorial logistic regression analysis was performed. RESULTS No significant differences were found in gender, age, TC, CRP, HDL-C, LDL-C, Cr, BP, smoking history, atherosclerosis and the proportion of uncontrolled hypertension between the two groups. The cognitive impairment group had lower education levels, and higher BMI, WHR, TG, FPG, FINS, and HOMA-IR levels than the control group. Logistic regression analysis revealed the levels of education, BMI, WHR, and HOMA-IR as independent factors that predict cognitive impairment in patients. CONCLUSION Our study demonstrates that poor education and increased BMI, WHR, and HOMA-IR are independent risk factors for cognitive impairment in elderly patients with hypertension. Insulin resistance plays an important role in the development of cognitive impairment in primary elderly hypertensive patients.
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Affiliation(s)
- Lina Ma
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Ming Feng
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Yuying Qian
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Wei Yang
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Jia Liu
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Rui Han
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Hong Zhu
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China
| | - Yun Li
- Department of Geriatrics, Xuan Wu Hospital, Capital Medical University, Beijing, China.
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8
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Steculorum SM, Solas M, Brüning JC. The paradox of neuronal insulin action and resistance in the development of aging-associated diseases. Alzheimers Dement 2014; 10:S3-11. [PMID: 24529522 DOI: 10.1016/j.jalz.2013.12.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 02/08/2023]
Abstract
During past decades, ever-increasing life expectancy, despite the development of a sedentary lifestyle and altered eating habits, has led to a dramatic parallel increase in the prevalence of age-related diseases such as type 2 diabetes mellitus (T2DM) and neurodegenerative disorders. Converging evidence from animal and human studies has indicated that insulin resistance in the central nervous system (CNS) is observed in both T2DM and neurodegenerative disorders such as Alzheimer's disease (AD), leading to the hypothesis that impaired neuronal insulin action might be a unifying pathomechanism in the development of both diseases. This assumption, however, is in striking contrast to the evolutionary conserved, protective role of impaired insulin/insulin-like growth factor 1 signaling (IIS) in aging and in protein aggregation-associated diseases, such as AD. Thus, this review summarizes our current understanding of the physiological role of insulin action in various regions of the CNS to regulate neuronal function, learning, and memory, and to control peripheral metabolism. We also discuss mechanisms and clinical outcomes of neuronal insulin resistance and address the seeming paradox of how impaired neuronal IIS can protect from the development of neurodegenerative disorders.
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Affiliation(s)
- Sophie M Steculorum
- Department of Mouse Genetics and Metabolism, Institute for Genetics, University of Cologne, Köln, Germany; Center for Endocrinology, Diabetes and Preventive Medicine, University Hospital Cologne, Köln, Germany; Center for Molecular Medicine Cologne, Köln, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Ageing Associated Diseases, Köln, Germany; Max-Planck-Institute for Neurological Research, Köln, Germany
| | - Maite Solas
- Department of Mouse Genetics and Metabolism, Institute for Genetics, University of Cologne, Köln, Germany; Center for Endocrinology, Diabetes and Preventive Medicine, University Hospital Cologne, Köln, Germany; Center for Molecular Medicine Cologne, Köln, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Ageing Associated Diseases, Köln, Germany; Max-Planck-Institute for Neurological Research, Köln, Germany
| | - Jens C Brüning
- Department of Mouse Genetics and Metabolism, Institute for Genetics, University of Cologne, Köln, Germany; Center for Endocrinology, Diabetes and Preventive Medicine, University Hospital Cologne, Köln, Germany; Center for Molecular Medicine Cologne, Köln, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Ageing Associated Diseases, Köln, Germany; Max-Planck-Institute for Neurological Research, Köln, Germany.
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9
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Li XZ, Zhang SN, Wang KX, Liu HY, Yang ZM, Liu SM, Lu F. Neuroprotective effects of extract of Acanthopanax senticosus harms on SH-SY5Y cells overexpressing wild-type or A53T mutant α-synuclein. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2014; 21:704-711. [PMID: 24252343 DOI: 10.1016/j.phymed.2013.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 09/16/2013] [Accepted: 10/11/2013] [Indexed: 06/02/2023]
Abstract
Extract of Acanthopanax senticosus harms (EAS) has been shown to have neuroprotective effects on dopaminergic neurons in Parkinson's disease (PD) mice model. α-Synuclein is a key player in the pathogenesis of PD, the elevated level of which is deleterious to dopaminergic neurons, and enhancing its clearance might be a promising strategy for treating PD. To assess the potential of EAS in this regard, we investigated its effect on the SH-SY5Y cells overexpressing wild-type α-synuclein (WT-α-Syn) or A53T mutant α-synuclein (A53T-α-Syn), and the implicated pathway it might mediate. After treatment with EAS, the changes of α-synuclein, caspase-3, parkin, phospho-protein kinase B (Akt), phospho-glycogen synthase kinase 3 beta (GSK3β), and phospho-microtubule-associated protein tau (Tau) in WT-α-Syn or A53T-α-Syn transgenic cells were reverted back to near normal levels, demonstrated by the western blotting and quantitative real-time PCR outcomes. The neuroprotective effects of EAS may be able to protect WT-α-Syn or A53T-α-Syn transgenic SH-SY5Y cells from α-synuclein overexpression and toxicity. Therefore, we speculate that EAS might be a promising candidate for prevention or treatment of α-synuclein-related neurodegenerative disorders such as PD.
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Affiliation(s)
- Xu-zhao Li
- Chinese Medicine Toxicological Laboratory, Institute of Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China
| | - Shuai-nan Zhang
- Chinese Medicine Toxicological Laboratory, Institute of Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China
| | - Ke-xin Wang
- Chinese Medicine Toxicological Laboratory, Institute of Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China
| | - Hong-yu Liu
- School of Basic Medical Sciences, Nanjing University of Chinese Medicine, Nanjing 210046, PR China
| | - Zhi-ming Yang
- Chinese Medicine Toxicological Laboratory, Institute of Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China
| | - Shu-min Liu
- Chinese Medicine Toxicological Laboratory, Institute of Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China; Drug Safety Evaluation Center, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China.
| | - Fang Lu
- Chinese Medicine Toxicological Laboratory, Institute of Traditional Chinese Medicine, Heilongjiang University of Chinese Medicine, Harbin 150040, PR China.
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10
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Zanuto R, Siqueira-Filho MA, Caperuto LC, Bacurau RFP, Hirata E, Peliciari-Garcia RA, do Amaral FG, Marçal AC, Ribeiro LM, Camporez JPG, Carpinelli AR, Bordin S, Cipolla-Neto J, Carvalho CRO. Melatonin improves insulin sensitivity independently of weight loss in old obese rats. J Pineal Res 2013; 55:156-65. [PMID: 23565768 DOI: 10.1111/jpi.12056] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 03/22/2013] [Indexed: 12/29/2022]
Abstract
In aged rats, insulin signaling pathway (ISP) is impaired in tissues that play a pivotal role in glucose homeostasis, such as liver, skeletal muscle, and adipose tissue. Moreover, the aging process is also associated with obesity and reduction in melatonin synthesis from the pineal gland and other organs. The aim of the present work was to evaluate, in male old obese Wistar rats, the effect of melatonin supplementation in the ISP, analyzing the total protein amount and the phosphorylated status (immunoprecipitation and immunoblotting) of the insulin cascade components in the rat hypothalamus, liver, skeletal muscle, and periepididymal adipose tissue. Melatonin was administered in the drinking water for 8- and 12 wk during the night period. Food and water intake and fasting blood glucose remained unchanged. The insulin sensitivity presented a 2.1-fold increase both after 8- and 12 wk of melatonin supplementation. Animals supplemented with melatonin for 12 wk also presented a reduction in body mass. The acute insulin-induced phosphorylation of the analyzed ISP proteins increased 1.3- and 2.3-fold after 8- and 12 wk of melatonin supplementation. The total protein content of the insulin receptor (IR) and the IR substrates (IRS-1, 2) remained unchanged in all investigated tissues, except for the 2-fold increase in the total amount of IRS-1 in the periepididymal adipose tissue. Therefore, the known age-related melatonin synthesis reduction may also be involved in the development of insulin resistance and the adequate supplementation could be an important alternative for the prevention of insulin signaling impairment in aged organisms.
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Affiliation(s)
- Ricardo Zanuto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences-I, University of São Paulo USP, São Paulo, SP, Brazil
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11
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Anisimov VN, Bartke A. The key role of growth hormone-insulin-IGF-1 signaling in aging and cancer. Crit Rev Oncol Hematol 2013; 87:201-23. [PMID: 23434537 PMCID: PMC4095988 DOI: 10.1016/j.critrevonc.2013.01.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/22/2012] [Accepted: 01/18/2013] [Indexed: 12/14/2022] Open
Abstract
Studies in mammals have led to the suggestion that hyperglycemia and hyperinsulinemia are important factors in aging. GH/Insulin/insulin-like growth factor-1 (IGF-1) signaling molecules that have been linked to longevity include daf-2 and InR and their homologues in mammals, and inactivation of the corresponding genes increases lifespan in nematodes, fruit flies and mice. The life-prolonging effects of caloric restriction are likely related to decreasing IGF-1 levels. Evidence has emerged that antidiabetic drugs are promising candidates for both lifespan extension and prevention of cancer. Thus, antidiabetic drugs postpone spontaneous carcinogenesis in mice and rats, as well as chemical and radiation carcinogenesis in mice, rats and hamsters. Furthermore, metformin seems to decrease the risk for cancer in diabetic patients.
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Affiliation(s)
- Vladimir N Anisimov
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov Research Institute of Oncology, St. Petersburg, Russia.
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12
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Pitt J, Thorner M, Brautigan D, Larner J, Klein WL. Protection against the synaptic targeting and toxicity of Alzheimer's-associated Aβ oligomers by insulin mimetic chiro-inositols. FASEB J 2013; 27:199-207. [PMID: 23073831 PMCID: PMC3528307 DOI: 10.1096/fj.12-211896] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 09/24/2012] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is a progressive dementia that correlates highly with synapse loss. This loss appears due to the synaptic accumulation of toxic Aβ oligomers (ADDLs), which damages synapse structure and function. Although it has been reported that oligomer binding and toxicity can be prevented by stimulation of neuronal insulin signaling with PPARγ agonists, these agonists have problematic side effects. We therefore investigated the therapeutic potential of chiro-inositols, insulin-sensitizing compounds safe for human consumption. Chiro-inositols have been studied extensively for treatment of diseases associated with peripheral insulin resistance, but their insulin mimetic function in memory-relevant central nervous system (CNS) cells is unknown. Here we demonstrate that mature cultures of hippocampal neurons respond to d-chiro-inositol (DCI), pinitol (3-O-methyl DCI), and the inositol glycan INS-2 (pinitol β-1-4 galactosamine) with increased phosphorylation in key upstream components in the insulin-signaling pathway (insulin receptor, insulin receptor substrate-1, and Akt). Consistent with insulin stimulation, DCI treatment promotes rapid withdrawal of dendritic insulin receptors. With respect to neuroprotection, DCI greatly enhances the ability of insulin to prevent ADDL-induced synapse damage (EC(50) of 90 nM). The mechanism comprises inhibition of oligomer binding at synapses and requires insulin/IGF signaling. DCI showed no effects on Aβ oligomerization. We propose that inositol glycans and DCI, a compound already established as safe for human consumption, have potential as AD therapeutics by protecting CNS synapses against Aβ oligomers through their insulin mimetic activity.
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Affiliation(s)
- Jason Pitt
- Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
| | - Michael Thorner
- Department of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - David Brautigan
- Department of Microbiology
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, Virginia, USA; and
| | - Joseph Larner
- Department of Pharmacology, and
- Allomed Pharmaceuticals, Charlottesville, Virginia, USA
| | - William L. Klein
- Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
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13
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Gong Z, Muzumdar RH. Pancreatic function, type 2 diabetes, and metabolism in aging. Int J Endocrinol 2012; 2012:320482. [PMID: 22675349 PMCID: PMC3362843 DOI: 10.1155/2012/320482] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/15/2012] [Accepted: 03/02/2012] [Indexed: 12/21/2022] Open
Abstract
Aging is a risk factor for impaired glucose tolerance and diabetes. Of the reported 25.8 million Americans estimated to have diabetes, 26.9% are over the age of 65. In certain ethnic groups, the proportion is even higher; almost 1 in 3 older Hispanics and African Americans and 3 out of 4 Pima Indian elders have diabetes. As per the NHANES III (Third National Health and Nutrition Examination) survey, the percentage of physician-diagnosed diabetes increased from 3.9% in middle-aged adults (40-49 years) to 13.2% in elderly adults (≥75 years). The higher incidence of diabetes is especially alarming considering that diabetes in itself increases the risk for multiple other age-related diseases such as cancer, stroke, cardiovascular diseases, Parkinson's disease, and Alzheimer's disease (AD). In this review, we summarize the current evidence on how aging affects pancreatic β cell function, β cell mass, insulin secretion and insulin sensitivity. We also review the effects of aging on the relationship between insulin sensitivity and insulin secretion. Understanding the mechanisms that lead to impaired glucose homeostasis and T2D in the elderly will lead to development of novel treatments that will prevent or delay diabetes, substantially improve quality of life and ultimately increase overall life span.
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Affiliation(s)
- Zhenwei Gong
- Department of Pediatrics, Divisions of Endocrinology and Geriatrics, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Radhika H. Muzumdar
- Department of Pediatrics, Divisions of Endocrinology and Geriatrics, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Medicine, Divisions of Endocrinology and Geriatrics, Children's Hospital at Montefiore, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
- *Radhika H. Muzumdar:
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Wilcox KC, Lacor PN, Pitt J, Klein WL. Aβ oligomer-induced synapse degeneration in Alzheimer's disease. Cell Mol Neurobiol 2011; 31:939-48. [PMID: 21538118 DOI: 10.1007/s10571-011-9691-4] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 04/07/2011] [Indexed: 12/12/2022]
Abstract
Aβ oligomers cause a collection of molecular events associated with memory loss in Alzheimer's disease, centering on disrupting the maintenance of synapse structure and function. In this brief review of the synaptotoxic effects of Aβ oligomers, we focus on the neuronal properties governing oligomer targeting and toxicity-especially with respect to binding sites and mechanisms of binding. We also discuss ways in which mechanistic insights from other diseases offer clues in the pursuit of the molecular basis of Alzheimer's disease.
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Affiliation(s)
- Kyle C Wilcox
- Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA.
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15
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Wu M, Fannin J, Rice KM, Wang B, Blough ER. Effect of aging on cellular mechanotransduction. Ageing Res Rev 2011; 10:1-15. [PMID: 19932197 DOI: 10.1016/j.arr.2009.11.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 11/11/2009] [Accepted: 11/16/2009] [Indexed: 12/27/2022]
Abstract
Aging is becoming a critical heath care issue and a burgeoning economic burden on society. Mechanotransduction is the ability of the cell to sense, process, and respond to mechanical stimuli and is an important regulator of physiologic function that has been found to play a role in regulating gene expression, protein synthesis, cell differentiation, tissue growth, and most recently, the pathophysiology of disease. Here we will review some of the recent findings of this field and attempt, where possible, to present changes in mechanotransduction that are associated with the aging process in several selected physiological systems, including musculoskeletal, cardiovascular, neuronal, respiratory systems and skin.
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Abstract
Studies in mammals have led to the suggestion that hyperglycemia and hyperinsulinemia are important factors in aging. Insulin/insulin-like growth factor 1 (IGF-1) signaling molecules that have been linked to longevity include daf-2 and InR and their homologues in mammals, and inactivation of the corresponding genes increases life span in nematodes, fruit flies and mice. It is possible that the life-prolonging effect of caloric restriction is due to decreasing IGF-1 levels. Evidence has emerged that antidiabetic drugs are promising candidates for both life span extension and prevention of cancer. Thus, antidiabetic drugs postpone spontaneous carcinogenesis in mice and rats, as well as chemical and radiation carcinogenesis in mice, rats and hamsters. Furthermore metformin seems to decrease cancer risk in diabetic patients.
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Affiliation(s)
- Vladimir N Anisimov
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov Research Institute of Oncology, St. Petersburg 197758, Russia.
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17
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Sadakata T, Furuichi T. Developmentally regulated Ca2+-dependent activator protein for secretion 2 (CAPS2) is involved in BDNF secretion and is associated with autism susceptibility. THE CEREBELLUM 2009; 8:312-22. [PMID: 19238500 DOI: 10.1007/s12311-009-0097-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 02/05/2009] [Indexed: 12/22/2022]
Abstract
The postnatal development of the cerebellum is accomplished via a series of cytogenetic and morphogenetic events encoded in the genome. To decipher the underlying genetic basis of these events we have systematized the spatio-temporal gene expression profiles during mouse cerebellar development in the Cerebellar Development Transcriptome Database (CDT-DB). Using the CDT-DB, Ca(2+)-dependent activator protein for secretion 2 (CAPS2 or CADPS2) was identified as a developmentally regulated gene that is predominantly expressed in cerebellar granule cells (GCs) with an expression peak around the first or second postnatal week. CAPS2 protein is concentrated in parallel fiber (PF) terminals and is associated with secretory vesicles containing brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3). CAPS2 enhances release of BDNF and NT-3, both of which are essential for normal cerebellar development. CAPS2-deficient (CAPS2(-/-)) mice show reduced secretion of BDNF and NT-3; consequently, the cerebella of these mice exhibit developmental deficits, such as delayed development and increased cell death in GCs, fewer branched dendrites on Purkinje cells (PCs), and loss of the intercrural fissure. The PF-PC synapses have aberrant cytoarchitectures and electrophysiological properties. These abnormal cellular and morphological phenotypes are more severe around the cerebellar vermis, in which hypoplasia has been reported in autism patients. Moreover, CAPS2(-/-) mice had fewer cortical and hippocampal parvalbumin-positive interneurons and some autistic-like behavioral phenotypes. In the CAPS2 genes of some autistic patients an aberrant splicing variant and non-synonymous SNPs have been identified. These recent studies implicate CAPS2 in autism susceptibility. Therefore, CAPS2(-/-) mice will be a useful model animal in which to study aspects of the neuropathology and behaviors characteristic of developmental disorders.
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Affiliation(s)
- Tetsushi Sadakata
- Laboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
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18
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Sabayan B, Foroughinia F, Mowla A, Borhanihaghighi A. Role of insulin metabolism disturbances in the development of Alzheimer disease: mini review. Am J Alzheimers Dis Other Demen 2008; 23:192-9. [PMID: 18198237 PMCID: PMC10846104 DOI: 10.1177/1533317507312623] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Alzheimer disease (AD) is the most common form of dementia. Different pathogenic processes have been studied that underlie characteristic changes of AD, including A beta protein aggregation, tau phosphorylation, neurovascular dysfunction, and inflammatory processes. Insulin exerts pleiotropic effects in neurons, such as the regulation of neural proliferation, apoptosis, and synaptic transmission. In this setting, any disturbance in the metabolism of insulin in the central nervous system (CNS) may put unfavorable effects on CNS function. It seems that disturbances in insulin metabolism, especially insulin resistance, play a role in most pathogenic processes that promote the development of AD. In this article, the relationships of disturbances in the metabolism of insulin in CNS with A beta peptides aggregation, tau protein phosphorylation, inflammatory markers, neuron apoptosis, neurovascular dysfunction, and neurotransmitter modulation are discussed, and future research directions are provided.
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Affiliation(s)
- Behnam Sabayan
- Student Research Center, Shiraz University of Medical Sciences, Shiraz, Islamic Republic of Iran
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19
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Liu QY, Sooknanan RR, Malek LT, Ribecco-Lutkiewicz M, Lei JX, Shen H, Lach B, Walker PR, Martin J, Sikorska M. Novel subtractive transcription-based amplification of mRNA (STAR) method and its application in search of rare and differentially expressed genes in AD brains. BMC Genomics 2006; 7:286. [PMID: 17090317 PMCID: PMC1637111 DOI: 10.1186/1471-2164-7-286] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 11/07/2006] [Indexed: 01/14/2023] Open
Abstract
Background Alzheimer's disease (AD) is a complex disorder that involves multiple biological processes. Many genes implicated in these processes may be present in low abundance in the human brain. DNA microarray analysis identifies changed genes that are expressed at high or moderate levels. Complementary to this approach, we described here a novel technology designed specifically to isolate rare and novel genes previously undetectable by other methods. We have used this method to identify differentially expressed genes in brains affected by AD. Our method, termed Subtractive Transcription-based Amplification of mRNA (STAR), is a combination of subtractive RNA/DNA hybridization and RNA amplification, which allows the removal of non-differentially expressed transcripts and the linear amplification of the differentially expressed genes. Results Using the STAR technology we have identified over 800 differentially expressed sequences in AD brains, both up- and down- regulated, compared to age-matched controls. Over 55% of the sequences represent genes of unknown function and roughly half of them were novel and rare discoveries in the human brain. The expression changes of nearly 80 unique genes were further confirmed by qRT-PCR and the association of additional genes with AD and/or neurodegeneration was established using an in-house literature mining tool (LitMiner). Conclusion The STAR process significantly amplifies unique and rare sequences relative to abundant housekeeping genes and, as a consequence, identifies genes not previously linked to AD. This method also offers new opportunities to study the subtle changes in gene expression that potentially contribute to the development and/or progression of AD.
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Affiliation(s)
- Qing Yan Liu
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6,Canada
| | - Roy R Sooknanan
- Alethia Biotheraputics Inc., 8475 Christophe-Colomb Avenue, Suite 1000 Montreal, Quebec, H2M 2N9, Canada
| | - Lawrence T Malek
- Osteopharm Inc., Unit 14, 1155 North Service Road, Oakville, Ontario, L6M 3E3, Canada
| | - Maria Ribecco-Lutkiewicz
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6,Canada
| | - Joy X Lei
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6,Canada
| | - Hui Shen
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6,Canada
| | - Boleslaw Lach
- Hamilton Health Sciences, Hamilton General Hospital, Laboratory Medicine, 237 Barton Str East, Hamilton, Ontario, L8L-2X2, Canada
| | - P Roy Walker
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6,Canada
| | - Joel Martin
- Interactive Information Group, Institute for Information Technology, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
| | - Marianna Sikorska
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6,Canada
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Lupien SB, Bluhm EJ, Ishii DN. Effect of IGF-I on DNA, RNA, and protein loss associated with brain atrophy and impaired learning in diabetic rats. Neurobiol Dis 2006; 21:487-95. [PMID: 16181784 DOI: 10.1016/j.nbd.2005.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Revised: 08/20/2005] [Accepted: 08/23/2005] [Indexed: 11/28/2022] Open
Abstract
Brain atrophy in diabetic dementia (DD) may be due to a catabolic state with DNA loss. Insulin-like growth factor (IGF) levels are reduced in diabetes, and IGF replacement may ameliorate brain protein loss. Subcutaneous minipumps released vehicle (Db + Veh) or IGF-I (Db + IGF-I) in diabetic rats. Brain wet, dry, and water weights as well as DNA, rRNA, poly(A)+ RNA, and protein contents per brain were significantly reduced in diabetic rats. In the remaining brain cells, there was a significant decline in ratios of (rRNA/DNA) and (protein/DNA). IGF-I administration partially prevented the loss of brain protein content independently of hyperglycemia (P < 0.03). This is the first demonstration of a severe disturbance in the brain protein regulatory pathway together with DNA loss in diabetes. Because Alzheimer's Disease (AD) is associated with a diabetes-like brain environment, a catabolic state may contribute to brain atrophy in sporadic AD as well as DD.
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Affiliation(s)
- Sean B Lupien
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
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21
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Affiliation(s)
- Vladimir N Anisimov
- Department of Carcinogenesis and Oncogerontology, N.N. Petrov Research Institute of Oncology, Pesochny-2, St. Petersburg, Russia
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22
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Farr SA, Banks WA, Uezu K, Gaskin FS, Morley JE. DHEAS improves learning and memory in aged SAMP8 mice but not in diabetic mice. Life Sci 2004; 75:2775-85. [PMID: 15464829 DOI: 10.1016/j.lfs.2004.05.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Accepted: 05/07/2004] [Indexed: 10/26/2022]
Abstract
Dehydroepiandrosterone sulfate (DHEAS) has been reported to improve memory in aged animals and suggested as a treatment for age-related dementias. The SAMP8 mouse, a model of Alzheimer's disease, has an age-related impairment in learning and memory and an increase in brain levels of amyloid precursor protein (APP) and amyloid beta protein (Abeta). Male SAMP8 mice also have a decrease in testosterone, to which DHEA is a precursor. Diabetes has been suggested as a model of aging and to be linked to Alzheimer's disease. Diabetics can have memory deficits and lower DHEAS levels. Here, we examined the effects of chronic oral DHEAS on acquisition and retention for T-maze footshock avoidance in 12 mo male SAMP8 mice and in CD-1 mice with streptozocin-induced diabetes. Learning and memory were improved in aged SAMP8 mice, but not in CD-1 mice with streptozocin-induced diabetes. These findings suggest that DHEAS is more effective in reversing the cognitive impairments associated with overexpression of Abeta than with diabetes.
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Affiliation(s)
- Susan A Farr
- Geriatric Research Education and Clinical Center (GRECC), VA Medical Center, St. Louis, MO, USA.
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Tran KT, Rusu SD, Satish L, Wells A. Aging-related attenuation of EGF receptor signaling is mediated in part by increased protein tyrosine phosphatase activity. Exp Cell Res 2003; 289:359-67. [PMID: 14499637 DOI: 10.1016/s0014-4827(03)00287-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
As fibroblasts near senescence, their responsiveness to external signals diminishes. This well-documented phenomenon likely underlies physiological deterioration and limited tissue regeneration in aging individuals. Understanding the underlying molecular mechanisms would provide opportunities to ameliorate these situations. A key stimulus for human dermal fibroblasts are ligands for the epidermal growth factor receptor (EGFR). We have shown earlier that EGFR expression decreases by about half in near senescent fibroblasts (Shiraha et al., 2000, J. Biol. Chem. 275 (25), 19343-19351). However, as the cell responses are nearly absent near senescence, other aging-related signal attenuation changes must also occur. Herein, we show that EGFR signaling as determined by receptor autophosphorylation is diminished over 80%, with a corresponding decrease in the phosphorylation of the immediate postreceptor adaptor Shc. Interestingly, we found that this was due at least in part to increased dephosphorylation of EGFR. The global cell phosphotyrosine phosphatase activity increased some threefold in near senescent cells. An initial survey of EGFR-associated protein tyrosine phosphatases (PTPases) showed that SHP-1 (PTPIC, HCP, SHPTP-1) and PTPIB levels are increased in parallel in these cells. Concomitantly, we also discovered an increase in expression of receptor protein tyrosine phosphatase alpha (RPTPalpha). Last, inhibition of protein tyrosine phosphatases by sodium orthovanadate in near senescent cells resulted in increased EGFR phosphorylation. These data support a model in which, near senescence, dermal fibroblasts become resistant to EGFR-mediated stimuli by a combination of receptor downregulation and increased signal attenuation.
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Affiliation(s)
- Kien T Tran
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Torsoni MA, Carvalheira JB, Pereira-Da-Silva M, de Carvalho-Filho MA, Saad MJA, Velloso LA. Molecular and functional resistance to insulin in hypothalamus of rats exposed to cold. Am J Physiol Endocrinol Metab 2003; 285:E216-23. [PMID: 12644444 DOI: 10.1152/ajpendo.00031.2003] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Insulin and leptin act in the hypothalamus, providing robust anorexigenic signals. The exposure of homeothermic animals to a cold environment leads to increased feeding, accompanied by sustained low levels of insulin and leptin. In the present study, the initial and intermediate steps of the insulin-signaling cascade were evaluated in the hypothalamus of cold-exposed Wistar rats. By immunohistochemistry, most insulin receptor (IR) and insulin receptor substrate-2 (IRS-2) immunoreactivity localized to the arcuate nucleus. Basal levels of tyrosine phosphorylation of IR and IRS-2 were increased in cold-exposed rats compared with rats maintained at room temperature. However, after an acute, peripheral infusion of exogenous insulin, significantly lower increases of IR and IRS-2 tyrosine phosphorylation were detected in the hypothalamus of cold-exposed rats. Insulin-induced association of p85/phosphatidylinositol 3-kinase with IRS-2, Ser473 phosphorylation of Akt, and tyrosine phosphorylation of ERK was significantly reduced in the hypothalamus of cold-exposed rats. To test the hypothesis of functional impairment of insulin signaling in the hypothalamus, intracerebroventricularly cannulated rats were acutely treated with insulin, and food ingestion was measured over a period of 12 h. Cold-exposed animals presented a significantly lower insulin-induced reduction in food consumption compared with animals maintained at room temperature. Hence, the present studies reveal that animals exposed to cold are resistant, both at the molecular and the functional level, to the actions of insulin in the hypothalamus.
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Affiliation(s)
- Márcio A Torsoni
- Department of Internal Medicine, State University of Campinas, Brazil
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