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Corrales A, Vidal R, García S, Vidal V, Martínez P, García E, Flórez J, Sanchez-Barceló EJ, Martínez-Cué C, Rueda N. Chronic melatonin treatment rescues electrophysiological and neuromorphological deficits in a mouse model of Down syndrome. J Pineal Res 2014; 56:51-61. [PMID: 24147912 DOI: 10.1111/jpi.12097] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 09/20/2013] [Indexed: 12/22/2022]
Abstract
The Ts65Dn mouse (TS), the most commonly used model of Down syndrome (DS), exhibits several key phenotypic characteristics of this condition. In particular, these animals present hypocellularity in different areas of their CNS due to impaired neurogenesis and have alterations in synaptic plasticity that compromise their cognitive performance. In addition, increases in oxidative stress during adulthood contribute to the age-related progression of cognitive and neuronal deterioration. We have previously demonstrated that chronic melatonin treatment improves learning and memory and reduces cholinergic neurodegeneration in TS mice. However, the molecular and physiological mechanisms that mediate these beneficial cognitive effects are not yet fully understood. In this study, we analyzed the effects of chronic melatonin treatment on different mechanisms that have been proposed to underlie the cognitive impairments observed in TS mice: reduced neurogenesis, altered synaptic plasticity, enhanced synaptic inhibition and oxidative damage. Chronic melatonin treatment rescued both impaired adult neurogenesis and the decreased density of hippocampal granule cells in trisomic mice. In addition, melatonin administration reduced synaptic inhibition in TS mice by increasing the density and/or activity of glutamatergic synapses in the hippocampus. These effects were accompanied by a full recovery of hippocampal LTP in trisomic animals. Finally, melatonin treatment decreased the levels of lipid peroxidation in the hippocampus of TS mice. These results indicate that the cognitive-enhancing effects of melatonin in adult TS mice could be mediated by the normalization of their electrophysiological and neuromorphological abnormalities and suggest that melatonin represents an effective treatment in retarding the progression of DS neuropathology.
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Affiliation(s)
- Andrea Corrales
- Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain
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Kelley CM, Powers BE, Velazquez R, Ash JA, Ginsberg SD, Strupp BJ, Mufson EJ. Sex differences in the cholinergic basal forebrain in the Ts65Dn mouse model of Down syndrome and Alzheimer's disease. Brain Pathol 2014; 24:33-44. [PMID: 23802663 PMCID: PMC4220609 DOI: 10.1111/bpa.12073] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 06/21/2013] [Indexed: 12/23/2022] Open
Abstract
In the Down syndrome (DS) population, there is an early incidence of dementia and neuropathology similar to that seen in sporadic Alzheimer's disease (AD), including dysfunction of the basal forebrain cholinergic neuron (BFCN) system. Using Ts65Dn mice, a model of DS and AD, we examined differences in the BFCN system between male and female segmentally trisomic (Ts65Dn) and disomic (2N) mice at ages 5-8 months. Quantitative stereology was applied to BFCN subfields immunolabeled for choline acetyltransferase (ChAT) within the medial septum/vertical limb of the diagonal band (MS/VDB), horizontal limb of the diagonal band (HDB) and nucleus basalis of Meynert/substantia innominata (NBM/SI). We found no sex differences in neuron number or subregion area measurement in the MS/VDB or HDB. However, 2N and Ts65Dn females showed an average 34% decrease in BFCN number and an average 20% smaller NBM/SI region area compared with genotype-matched males. Further, relative to genotype-matched males, female mice had smaller BFCNs in all subregions. These findings demonstrate that differences between the sexes in BFCNs of young adult Ts65Dn and 2N mice are region and genotype specific. In addition, changes in post-processing tissue thickness suggest altered parenchymal characteristics between male and female Ts65Dn mice.
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Affiliation(s)
- Christy M. Kelley
- Department of Neurological SciencesRush University Medical CenterChicagoIL
| | - Brian E. Powers
- Division of Nutritional Sciences and Department of PsychologyCornell UniversityIthacaNY
| | - Ramon Velazquez
- Division of Nutritional Sciences and Department of PsychologyCornell UniversityIthacaNY
| | - Jessica A. Ash
- Division of Nutritional Sciences and Department of PsychologyCornell UniversityIthacaNY
| | - Stephen D. Ginsberg
- Center for Dementia ResearchNathan Kline InstituteOrangeburgNY
- Department of PsychiatryNew York University Langone Medical CenterNew YorkNY
- Department of Physiology & NeuroscienceNew York University Langone Medical CenterNew YorkNY
| | - Barbara J. Strupp
- Division of Nutritional Sciences and Department of PsychologyCornell UniversityIthacaNY
| | - Elliott J. Mufson
- Department of Neurological SciencesRush University Medical CenterChicagoIL
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Velazquez R, Ash JA, Powers BE, Kelley CM, Strawderman M, Luscher ZI, Ginsberg SD, Mufson EJ, Strupp BJ. Maternal choline supplementation improves spatial learning and adult hippocampal neurogenesis in the Ts65Dn mouse model of Down syndrome. Neurobiol Dis 2013; 58:92-101. [PMID: 23643842 PMCID: PMC4029409 DOI: 10.1016/j.nbd.2013.04.016] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 04/12/2013] [Accepted: 04/23/2013] [Indexed: 11/25/2022] Open
Abstract
In addition to intellectual disability, individuals with Down syndrome (DS) exhibit dementia by the third or fourth decade of life, due to the early onset of neuropathological changes typical of Alzheimer's disease (AD). Deficient ontogenetic neurogenesis contributes to the brain hypoplasia and hypocellularity evident in fetuses and children with DS. A murine model of DS and AD (the Ts65Dn mouse) exhibits key features of these disorders, notably deficient ontogenetic neurogenesis, degeneration of basal forebrain cholinergic neurons (BFCNs), and cognitive deficits. Adult hippocampal (HP) neurogenesis is also deficient in Ts65Dn mice and may contribute to the observed cognitive dysfunction. Herein, we demonstrate that supplementing the maternal diet with additional choline (approximately 4.5 times the amount in normal rodent chow) dramatically improved the performance of the adult trisomic offspring in a radial arm water maze task. Ts65Dn offspring of choline-supplemented dams performed significantly better than unsupplemented Ts65Dn mice. Furthermore, adult hippocampal neurogenesis was partially normalized in the maternal choline supplemented (MCS) trisomic offspring relative to their unsupplemented counterparts. A significant correlation was observed between adult hippocampal neurogenesis and performance in the water maze, suggesting that the increased neurogenesis seen in the supplemented trisomic mice contributed functionally to their improved spatial cognition. These findings suggest that supplementing the maternal diet with additional choline has significant translational potential for DS.
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Affiliation(s)
- Ramon Velazquez
- Div. Nutritional Sciences and Dept of Psychology, Cornell University, Ithaca, NY 14853
| | - Jessica A. Ash
- Div. Nutritional Sciences and Dept of Psychology, Cornell University, Ithaca, NY 14853
| | - Brian E. Powers
- Div. Nutritional Sciences and Dept of Psychology, Cornell University, Ithaca, NY 14853
| | - Christy M. Kelley
- Dept. Neurological Science and Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612
| | - Myla Strawderman
- Div. Nutritional Sciences and Dept of Psychology, Cornell University, Ithaca, NY 14853
| | - Zoe I. Luscher
- Div. Nutritional Sciences and Dept of Psychology, Cornell University, Ithaca, NY 14853
| | - Stephen D. Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, and Departments of Psychiatry, and Physiology & Neuroscience, New York University Langone Medical Center, New York, NY 10962
| | - Elliott J. Mufson
- Dept. Neurological Science and Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612
| | - Barbara J. Strupp
- Div. Nutritional Sciences and Dept of Psychology, Cornell University, Ithaca, NY 14853
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Abstract
Down syndrome (DS), which results from an extra copy of chromosome 21 (trisomy 21), is the most common genetically defined cause of intellectual disability. Although no pharmacotherapy aimed at counteracting the cognitive and adaptive deficits associated with this genetic disorder has been approved at present, there have been several new promising studies on pharmacological agents capable of rescuing learning/memory deficits seen in mouse models of DS. Here, we will review the available mouse models for DS and provide a comprehensive, albeit not exhaustive review of the following preclinical research strategies: (1) SOD1 and antioxidant agents; (2) APP and γ-secretase inhibitors; (3) DYRK1A and the polyphenol epigallocatechin gallate (EGCG); (4) GIRK2 and fluoxetine; (5) adrenergic receptor agonists; (6) modulation of GABAA and GABAB receptors; (7) agonism of the hedgehog signaling pathway; (8) nerve growth factor (NGF) and other neurotrophic factors; (9) anticholinesterase (AChE) agents; and (10) antagonism of NMDA receptors. Finally, we will review briefly five different strategies in DS that have led to clinical studies that either have been concluded or are currently underway: (1) antioxidant therapy; (2) AChE therapy; (3) green tea extract therapy; (4) RG1662 therapy; and (5) memantine therapy. These are exciting times in DS research. Within a decade or so, it is well into the realm of possibility that new forms of pharmacotherapies might become valuable tools in the armamentarium of developmental clinicians, as adjutants to more traditional and proven forms of habilitative interventions aimed at improving the quality of life of individuals with DS.
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Hellwig S, Heinrich A, Biber K. The brain's best friend: microglial neurotoxicity revisited. Front Cell Neurosci 2013; 7:71. [PMID: 23734099 PMCID: PMC3655268 DOI: 10.3389/fncel.2013.00071] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 04/26/2013] [Indexed: 01/13/2023] Open
Abstract
One long standing aspect of microglia biology was never questioned; their involvement in brain disease. Based on morphological changes (retracted processes and amoeboid shape) that inevitably occur in these cells in case of damage in the central nervous system, microglia in the diseased brain were called “activated.” Because “activated” microglia were always found in direct neighborhood to dead or dying neuron, and since it is known now for more than 20 years that cultured microglia release numerous factors that are able to kill neurons, microglia “activation” was often seen as a neurotoxic process. From an evolutionary point of view, however, it is difficult to understand why an important, mostly post-mitotic and highly vulnerable organ like the brain would host numerous potential killers. This review is aimed to critically reconsider the term microglia neurotoxicity and to discuss experimental problems around microglia biology, that often have led to the conclusion that microglia are neurotoxic cells.
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Affiliation(s)
- Sabine Hellwig
- Department of Psychiatry and Psychotherapy, University Hospital Freiburg Freiburg, Germany
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Effects of minocycline on spatial learning, hippocampal neurogenesis and microglia in aged and adult mice. Behav Brain Res 2012; 242:17-24. [PMID: 23274840 DOI: 10.1016/j.bbr.2012.12.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 12/10/2012] [Accepted: 12/13/2012] [Indexed: 11/23/2022]
Abstract
Age-related priming of microglia and release of inflammatory cytokines, such as interleukin-1β (IL-1β) and interleuekin-6 (IL-6) have been associated with deficits in cognitive function. The present study assessed whether treatment with minocycline could improve spatial cognition in aged mice, and whether these improvements in behavior were associated with reduced microglia activation and an enhancement in hippocampal neurogenesis. Adult (3 months) and aged (22 months) male BALB/c mice received minocycline in their drinking water or control mice received distilled water for 20 days. Mice received BrdU to label dividing cells on days 8-17. Spatial learning was measured using the water maze. Immunohistochemistry was conducted to measure number of BrdU positive neurons and number and size of microglia by detection of Iba-1 in the dentate gyrus molecular layer. Further, hippocampal samples were collected to measure changes in IL-1β, IL-6, and CD74 expression. The data show that aged mice have increased hippocampal expression of IL-1β, IL-6, and CD74 relative to adults. Minocycline treatment significantly improved acquisition of the water maze in aged mice but not adults. Minocycline reduced the average size of Iba-1 positive cells and total Iba-1 counts, but did not affect hippocampal cytokine gene expression. Minocycline increased neurogenesis in adults but not aged mice. Collectively, the data indicate that treatment with minocycline may recover some aspects of cognitive decline associated with aging, but the effect appears to be unrelated to adult hippocampal neurogenesis.
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58
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What is behind the non-antibiotic properties of minocycline? Pharmacol Res 2012; 67:18-30. [PMID: 23085382 DOI: 10.1016/j.phrs.2012.10.006] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 09/13/2012] [Accepted: 10/09/2012] [Indexed: 11/24/2022]
Abstract
Minocycline is a second-generation, semi-synthetic tetracycline that has been in use in therapy for over 30 years for its antibiotic properties against both Gram-positive and Gram-negative bacteria. It displays antibiotic activity due to its ability to bind to the 30S ribosomal subunit of bacteria and thus inhibit protein synthesis. More recently, it has been described to exert a variety of biological actions beyond its antimicrobial activity, including anti-inflammatory and anti-apoptotic activities, inhibition of proteolysis, as well as suppression of angiogenesis and tumor metastasis, which have been confirmed in different experimental models of non-infectious diseases. There are also many studies that have focused on the mechanisms involved in these non-antibiotic properties of minocycline, including anti-oxidant activity, inhibition of several enzyme activities, inhibition of apoptosis and regulation of immune cell activation and proliferation. This review summarizes the current findings in this topic, mainly focusing on the mechanisms underlying the immunomodulatory and anti-inflammatory activities of minocycline.
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Won SJ, Kim JH, Yoo BH, Sohn M, Kauppinen TM, Park MS, Kwon HJ, Liu J, Suh SW. Prevention of hypoglycemia-induced neuronal death by minocycline. J Neuroinflammation 2012; 9:225. [PMID: 22998689 PMCID: PMC3511289 DOI: 10.1186/1742-2094-9-225] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 09/14/2012] [Indexed: 02/03/2023] Open
Abstract
Diabetic patients who attempt strict management of blood glucose levels frequently experience hypoglycemia. Severe and prolonged hypoglycemia causes neuronal death and cognitive impairment. There is no effective tool for prevention of these unwanted clinical sequelae. Minocycline, a second-generation tetracycline derivative, has been recognized as an anti-inflammatory and neuroprotective agent in several animal models such as stroke and traumatic brain injury. In the present study, we tested whether minocycline also has protective effects on hypoglycemia-induced neuronal death and cognitive impairment. To test our hypothesis we used an animal model of insulin-induced acute hypoglycemia. Minocycline was injected intraperitoneally at 6 hours after hypoglycemia/glucose reperfusion and injected once per day for the following 1 week. Histological evaluation for neuronal death and microglial activation was performed from 1 day to 1 week after hypoglycemia. Cognitive evaluation was conducted 6 weeks after hypoglycemia. Microglial activation began to be evident in the hippocampal area at 1 day after hypoglycemia and persisted for 1 week. Minocycline injection significantly reduced hypoglycemia-induced microglial activation and myeloperoxidase (MPO) immunoreactivity. Neuronal death was significantly reduced by minocycline treatment when evaluated at 1 week after hypoglycemia. Hypoglycemia-induced cognitive impairment is also significantly prevented by the same minocycline regimen when subjects were evaluated at 6 weeks after hypoglycemia. Therefore, these results suggest that delayed treatment (6 hours post-insult) with minocycline protects against microglial activation, neuronal death and cognitive impairment caused by severe hypoglycemia. The present study suggests that minocycline has therapeutic potential to prevent hypoglycemia-induced brain injury in diabetic patients.
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Affiliation(s)
- Seok Joon Won
- Department of Neurology, University of California San Francisco and Veterans Affairs Medical Center, San Francisco, CA 94121, USA
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60
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Molecular and cellular alterations in Down syndrome: toward the identification of targets for therapeutics. Neural Plast 2012; 2012:171639. [PMID: 22848846 PMCID: PMC3403492 DOI: 10.1155/2012/171639] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/18/2012] [Accepted: 04/19/2012] [Indexed: 12/25/2022] Open
Abstract
Down syndrome is a complex disease that has challenged molecular and cellular research for more than 50 years. Understanding the molecular bases of morphological, cellular, and functional alterations resulting from the presence of an additional complete chromosome 21 would aid in targeting specific genes and pathways for rescuing some phenotypes. Recently, progress has been made by characterization of brain alterations in mouse models of Down syndrome. This review will highlight the main molecular and cellular findings recently described for these models, particularly with respect to their relationship to Down syndrome phenotypes.
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Mouse models of Down syndrome as a tool to unravel the causes of mental disabilities. Neural Plast 2012; 2012:584071. [PMID: 22685678 PMCID: PMC3364589 DOI: 10.1155/2012/584071] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/23/2012] [Accepted: 03/24/2012] [Indexed: 12/16/2022] Open
Abstract
Down syndrome (DS) is the most common genetic cause of mental disability. Based on the homology of Hsa21 and the murine chromosomes Mmu16, Mmu17 and Mmu10, several mouse models of DS have been developed. The most commonly used model, the Ts65Dn mouse, has been widely used to investigate the neural mechanisms underlying the mental disabilities seen in DS individuals. A wide array of neuromorphological alterations appears to compromise cognitive performance in trisomic mice. Enhanced inhibition due to alterations in GABA(A)-mediated transmission and disturbances in the glutamatergic, noradrenergic and cholinergic systems, among others, has also been demonstrated. DS cognitive dysfunction caused by neurodevelopmental alterations is worsened in later life stages by neurodegenerative processes. A number of pharmacological therapies have been shown to partially restore morphological anomalies concomitantly with cognition in these mice. In conclusion, the use of mouse models is enormously effective in the study of the neurobiological substrates of mental disabilities in DS and in the testing of therapies that rescue these alterations. These studies provide the basis for developing clinical trials in DS individuals and sustain the hope that some of these drugs will be useful in rescuing mental disabilities in DS individuals.
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Biscaro B, Lindvall O, Tesco G, Ekdahl CT, Nitsch RM. Inhibition of microglial activation protects hippocampal neurogenesis and improves cognitive deficits in a transgenic mouse model for Alzheimer's disease. NEURODEGENER DIS 2012; 9:187-98. [PMID: 22584394 DOI: 10.1159/000330363] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Accepted: 06/28/2011] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Activated microglia with macrophage-like functions invade and surround β-amyloid (Aβ) plaques in Alzheimer's disease (AD), possibly contributing to the turnover of Aβ, but they can also secrete proinflammatory factors that may be involved in the pathogenesis of AD. Microglia are known to modulate adult hippocampal neurogenesis. OBJECTIVES/METHODS To determine the role of microglia on neurogenesis in brains with Aβ pathology, we inhibited microglial activation with the tetracycline derivative minocycline in doubly transgenic mice expressing mutant human amyloid precursor protein (APP) and mutant human presenilin-1 (PS1). RESULTS Minocycline increased the survival of new dentate granule cells in APP/PS1 mice indicated by more BrdU+/NeuN+ cells as compared to vehicle-treated transgenic littermates, accompanied by improved behavioral performance in a hippocampus-dependent learning task. Both brain levels of Aβ and Aβ-related morphological deficits in the new neurons labeled with GFP-expressing retrovirus were unaffected in minocycline-treated mice. CONCLUSIONS These results suggest a role for microglia in Aβ-related functional deficits and in suppressing the survival of new neurons, and show that modulation of microglial function with minocycline can protect hippocampal neurogenesis in the presence of Aβ pathology.
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Affiliation(s)
- Barbara Biscaro
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland.
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63
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Lockrow JP, Fortress AM, Granholm ACE. Age-related neurodegeneration and memory loss in down syndrome. Curr Gerontol Geriatr Res 2012; 2012:463909. [PMID: 22545043 PMCID: PMC3318235 DOI: 10.1155/2012/463909] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 11/21/2011] [Indexed: 01/10/2023] Open
Abstract
Down syndrome (DS) is a condition where a complete or segmental chromosome 21 trisomy causes variable intellectual disability, and progressive memory loss and neurodegeneration with age. Many research groups have examined development of the brain in DS individuals, but studies on age-related changes should also be considered, with the increased lifespan observed in DS. DS leads to pathological hallmarks of Alzheimer's disease (AD) by 40 or 50 years of age. Progressive age-related memory deficits occurring in both AD and in DS have been connected to degeneration of several neuronal populations, but mechanisms are not fully elucidated. Inflammation and oxidative stress are early events in DS pathology, and focusing on these pathways may lead to development of successful intervention strategies for AD associated with DS. Here we discuss recent findings and potential treatment avenues regarding development of AD neuropathology and memory loss in DS.
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Affiliation(s)
- Jason P. Lockrow
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
| | - Ashley M. Fortress
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
| | - Ann-Charlotte E. Granholm
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
- Center on Aging, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA
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Lockrow J, Boger H, Gerhardt G, Aston-Jones G, Bachman D, Granholm AC. A noradrenergic lesion exacerbates neurodegeneration in a Down syndrome mouse model. J Alzheimers Dis 2011; 23:471-89. [PMID: 21098982 DOI: 10.3233/jad-2010-101218] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Individuals with Down syndrome (DS) acquire Alzheimer's-like dementia (AD) and associated neuropathology earlier and at significantly greater rates than age-matched normosomic individuals. However, biological mechanisms have not been discovered and there is currently limited therapy for either DS- or AD-related dementia. Segmental trisomy 16 (Ts65Dn) mice provide a useful model for many of the degenerative changes which occur with age in DS including cognitive deficits, neuroinflammation, and degeneration of basal forebrain cholinergic neurons. Loss of noradrenergic locus coeruleus (LC) neurons is an early event in AD and in DS, and may contribute to the neuropathology. We report that Ts65Dn mice exhibit progressive loss of norepinephrine (NE) phenotype in LC neurons. In order to determine whether LC degeneration contributes to memory loss and neurodegeneration in Ts65Dn mice, we administered the noradrenergic neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4; 2 doses of 50 mg/kg, i.p.) to Ts65Dn mice at four months of age, prior to working memory loss. At eight months of age, Ts65Dn mice treated with DSP-4 exhibited an 80% reduction in hippocampal NE, coupled with a marked increase in hippocampal neuroinflammation. Noradrenergic depletion also resulted in accelerated cholinergic neuron degeneration and a further impairment of memory function in Ts65Dn mice. In contrast, DSP-4 had minimal effects on normosomic littermates, suggesting a disease-modulated vulnerability to NE loss in the DS mouse model. These data suggest that noradrenergic degeneration may play a role in the progressive memory loss, neuroinflammation, and cholinergic loss occurring in DS individuals, providing a possible therapeutic avenue for future clinical studies.
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Affiliation(s)
- Jason Lockrow
- Department of Neurosciences and the Medical University of South Carolina, Charleston, SC 29425, USA
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65
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Gotti S, Caricati E, Panzica G. Alterations of brain circuits in Down syndrome murine models. J Chem Neuroanat 2011; 42:317-26. [DOI: 10.1016/j.jchemneu.2011.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 09/04/2011] [Accepted: 09/06/2011] [Indexed: 10/17/2022]
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Real MA, Simón MP, Heredia R, de Diego Y, Guirado S. Phenotypic changes in calbindin D28K immunoreactivity in the hippocampus of Fmr1 knockout mice. J Comp Neurol 2011; 519:2622-36. [PMID: 21491426 DOI: 10.1002/cne.22643] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Fragile X syndrome (FXS), the most prevalent form of inherited mental retardation, is caused by the lack of FMRP (fragile mental retardation protein) as a result of the transcriptional silencing of the FMR1 gene. Here we analyze the immunohistochemical expression of the calbindin D28K protein in the hippocampus of Fmr1 knockout (KO) mice and compare it with that of their wildtype (WT) littermates. The spatial distribution pattern of calbindin-immunoreactive cells in the hippocampus was similar in WT and KO mice but for each age studied (ranging from 3.5-8 months) the dentate gyrus of Fmr1-KO mice showed a significant reduction in calbindin-immunoreactive granule cells. Also, the number of calbindin-immunoreactive cells was reduced in the CA1 pyramidal layer in KO mice compared to their WT littermates. In addition, Frm1-KO mice showed a group of calbindin-immunoreactive cells located only in the left CA3b subregion that was only sometimes observed in WT mice. Overall, the absence of FMRP results in a dysregulation of the calbindin protein expression in the hippocampus. This dysregulation is cell type- and time-dependent and as a consequence key elements of the hippocampal trisynaptic circuitry may lack calbindin in critical periods for normal memory/learning abilities to be achieved and may explain some of the FXS symptoms observed in the Fmr1-KO mouse model.
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Affiliation(s)
- M Angeles Real
- University of Málaga, Department of Cell Biology, Genetics, and Physiology, Málaga, Spain
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67
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Ho EL, Spudich SS, Lee E, Fuchs D, Sinclair E, Price RW. Minocycline fails to modulate cerebrospinal fluid HIV infection or immune activation in chronic untreated HIV-1 infection: results of a pilot study. AIDS Res Ther 2011; 8:17. [PMID: 21569420 PMCID: PMC3117676 DOI: 10.1186/1742-6405-8-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 05/12/2011] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Minocycline is a tetracycline antibiotic that has been shown to attenuate central nervous system (CNS) lentivirus infection, immune activation, and brain injury in model systems. To initiate assessment of minocycline as an adjuvant therapy in human CNS HIV infection, we conducted an open-labelled pilot study of its effects on cerebrospinal fluid (CSF) and blood biomarkers of infection and immune responses in 7 viremic subjects not taking antiretroviral therapy. RESULTS There were no discernable effects of minocycline on CSF or blood HIV-1 RNA, or biomarkers of immune activation and inflammation including: CSF and blood neopterin, CSF CCL2, CSF white blood cell count, and expression of cell-surface activation markers on CSF and blood T lymphocytes and monocytes. CONCLUSIONS This pilot study of biological responses to minocycline suggests little potential for its use as adjunctive antiviral or immunomodulating therapy in chronic untreated HIV infection.
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Bartesaghi R, Guidi S, Ciani E. Is it possible to improve neurodevelopmental abnormalities in Down syndrome? Rev Neurosci 2011; 22:419-55. [DOI: 10.1515/rns.2011.037] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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69
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Stimulated neuronal expression of brain-derived neurotrophic factor by Neurotropin. Mol Cell Neurosci 2010; 45:226-33. [DOI: 10.1016/j.mcn.2010.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 06/02/2010] [Accepted: 06/18/2010] [Indexed: 02/06/2023] Open
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Lockrow J, Boger H, Bimonte-Nelson H, Granholm AC. Effects of long-term memantine on memory and neuropathology in Ts65Dn mice, a model for Down syndrome. Behav Brain Res 2010; 221:610-22. [PMID: 20363261 DOI: 10.1016/j.bbr.2010.03.036] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 12/09/2009] [Accepted: 03/22/2010] [Indexed: 01/22/2023]
Abstract
Memantine is a partial NMDA receptor antagonist that has been shown to improve learning and memory in several animal models, and is approved for the treatment of Alzheimer's disease (AD). Chronic treatments using memantine in animal models of Alzheimer's disease show disease-modifying effects and suggest a potential neuroprotective function. The present study assessed the effects of both short- and long-term memantine treatment in a mouse model of Down syndrome (DS), the Ts65Dn mouse. The Ts65Dn mouse contains a partial trisomy of murine chromosome 16, and exhibits hippocampal-dependent memory deficits, as well as progressive degeneration of basal forebrain cholinergic neurons (BCFNs). Ts65Dn mice were treated with memantine for a period of 6 months, beginning at 4 months of age. At the end of treatment the mice underwent memory testing using novel object recognition and water radial arm maze tasks, and then histologically analyzed for markers of neurodegeneration. Memantine treatment improved spatial and recognition memory performance in the Ts65Dn mice, though not to the level of normosomic littermate controls. Despite these memory improvements, histological analysis found no morphological signs of neuroprotection of basal forebrain cholinergic or locus coeruleus neurons in memantine-treated Ts65Dn mice. However, memantine treatment of Ts65Dn mice gave rise to elevated brain-derived neurotrophic factor expression in the hippocampus and frontal cortex, suggesting a mechanism of behavioral modification. Thus, our findings provide further evidence for memory facilitation of memantine, but suggest pharmacological rather than neuroprotective effects of memantine both after acute and chronic treatment in this mouse model.
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Affiliation(s)
- Jason Lockrow
- Department of Neuroscience, Center on Aging, Medical University of South Carolina, 173 Ashley Avenue, Ste 410D, Charleston, SC 29425, USA
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71
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Alteration of inhibitory circuits in the somatosensory cortex of Ts65Dn mice, a model for Down’s syndrome. J Neural Transm (Vienna) 2010; 117:445-55. [DOI: 10.1007/s00702-010-0376-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 01/27/2010] [Indexed: 10/19/2022]
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72
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Gardiner KJ. Molecular basis of pharmacotherapies for cognition in Down syndrome. Trends Pharmacol Sci 2010; 31:66-73. [PMID: 19963286 PMCID: PMC2815198 DOI: 10.1016/j.tips.2009.10.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/27/2009] [Accepted: 10/30/2009] [Indexed: 12/18/2022]
Abstract
Intellectual disability in Down syndrome (DS) ranges from low normal to severely impaired and has a significant impact on the quality-of-life of the individuals affected and their families. Because the incidence of DS remains at approximately 1 in 700 live births and the lifespan is now >50 years, development of pharmacotherapies for cognitive deficits is an important goal. DS is due to an extra copy of human chromosome 21 and has often been considered too complex a genetic abnormality to be amenable to intervention. However, recent successes in rescuing learning/memory impairments in a mouse model of DS suggest that this negative outlook may not be justified. In this contribution, we first review the DS phenotype, chromosome 21 gene content and mouse models. We then discuss recent successes and the remaining challenges in the identification of targets for and preclinical evaluation of potential therapeutics.
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Affiliation(s)
- Katheleen J Gardiner
- Department of Pediatrics, Intellectual and Developmental Disability Research Center, Human Medical Genetics and Neuroscience Programs, University of Colorado Denver, 12800 E 19(th) Avenue, Aurora, Colorado 80045, USA.
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Communication breaks-Down: from neurodevelopment defects to cognitive disabilities in Down syndrome. Prog Neurobiol 2010; 91:1-22. [PMID: 20097253 DOI: 10.1016/j.pneurobio.2010.01.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 12/10/2009] [Accepted: 01/14/2010] [Indexed: 12/31/2022]
Abstract
Down syndrome (DS) is the leading cause of genetically-defined intellectual disability and congenital birth defects. Despite being one of the first genetic diseases identified, only recently, thanks to the phenotypic analysis of DS mouse genetic models, we have begun to understand how trisomy may impact cognitive function. Cognitive disabilities in DS appear to result mainly from two pathological processes: neurogenesis impairment and Alzheimer-like degeneration. In DS brain, suboptimal network architecture and altered synaptic communication arising from neurodevelopmental impairment are key determinants of cognitive defects. Hypocellularity and hypoplasia start at early developmental stages and likely depend upon impaired proliferation of neuronal precursors, resulting in reduction of numbers of neurons and synaptic contacts. The impairment of neuronal precursor proliferation extends to adult neurogenesis and may affect learning and memory. Neurodegenerative mechanisms also contribute to DS cognitive impairment. Early onset Alzheimer disease occurs with extremely high incidence in DS patients and is causally-related to overexpression of beta-amyloid precursor protein (betaAPP), which is one of the triplicated genes in DS. In this review, we will survey the available findings on neurodevelopmental and neurodegenerative changes occurring in DS throughout life. Moreover, we will discuss the potential mechanisms by which defects in neurogenesis and neurodegenerative processes lead to altered formation of neural circuits and impair cognitive function, in connection with findings on pharmacological treatments of potential benefit for DS.
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74
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Amyloid beta-induced nerve growth factor dysmetabolism in Alzheimer disease. J Neuropathol Exp Neurol 2009; 68:857-69. [PMID: 19606067 DOI: 10.1097/nen.0b013e3181aed9e6] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
We previously reported that the precursor form of nerve growth factor (pro-NGF) and not mature NGF is liberated in the CNS in an activity-dependent manner, and that its maturation and degradation occur in the extracellular space by the coordinated action of proteases.Here, we present evidence of diminished conversion of pro-NGF to its mature form and of greater NGF degradation in Alzheimer disease (AD) brain samples compared with controls. These alterations of the NGF metabolic pathway likely resulted in the increased pro-NGF levels. The pro-NGF was largely in a peroxynitrited form in the AD samples. Intrahippocampal injection of amyloid-beta oligomers provoked similar upregulation of pro-NGF in naive rats that was accompanied by evidence of microglial activation (CD40), increased levels of inducible nitric oxide synthase, and increased activity of the NGF-degrading enzyme matrix metalloproteinase 9. The elevated inducible nitric oxide synthase provoked the generation of biologically inactive, peroxynitrite-modified pro-NGF in amyloid-beta oligomer-injected rats. These parameters were corrected by minocycline treatment. Minocycline also diminished altered matrix metalloproteinase 9, inducible nitric oxide synthase, and microglial activation (CD40); improved cognitive behavior; and normalized pro-NGF levels in a transgenic mouse AD model. The effects of amyloid-beta amyloid CNS burden on NGF metabolism may explain the paradoxical upregulation of pro-NGF in AD accompanied by atrophy of forebrain cholinergic neurons.
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75
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Dierssen M, Herault Y, Estivill X. Aneuploidy: from a physiological mechanism of variance to Down syndrome. Physiol Rev 2009; 89:887-920. [PMID: 19584316 DOI: 10.1152/physrev.00032.2007] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Quantitative differences in gene expression emerge as a significant source of variation in natural populations, representing an important substrate for evolution and accounting for a considerable fraction of phenotypic diversity. However, perturbation of gene expression is also the main factor in determining the molecular pathogenesis of numerous aneuploid disorders. In this review, we focus on Down syndrome (DS) as the prototype of "genomic disorder" induced by copy number change. The understanding of the pathogenicity of the extra genomic material in trisomy 21 has accelerated in the last years due to the recent advances in genome sequencing, comparative genome analysis, functional genome exploration, and the use of model organisms. We present recent data on the role of genome-altering processes in the generation of diversity in DS neural phenotypes focusing on the impact of trisomy on brain structure and mental retardation and on biological pathways and cell types in target brain regions (including prefrontal cortex, hippocampus, cerebellum, and basal ganglia). We also review the potential that genetically engineered mouse models of DS bring into the understanding of the molecular biology of human learning disorders.
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Affiliation(s)
- Mara Dierssen
- Genes and Disease Program, Genomic Regulation Center-CRG, Pompeu Fabra University, Barcelona Biomedical Research Park, Dr Aiguader 88, PRBB building E, Barcelona 08003, Catalonia, Spain.
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76
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Wiseman FK, Alford KA, Tybulewicz VLJ, Fisher EMC. Down syndrome--recent progress and future prospects. Hum Mol Genet 2009; 18:R75-83. [PMID: 19297404 PMCID: PMC2657943 DOI: 10.1093/hmg/ddp010] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Down syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and is associated with a number of deleterious phenotypes, including learning disability, heart defects, early-onset Alzheimer's disease and childhood leukaemia. Individuals with DS are affected by these phenotypes to a variable extent; understanding the cause of this variation is a key challenge. Here, we review recent research progress in DS, both in patients and relevant animal models. In particular, we highlight exciting advances in therapy to improve cognitive function in people with DS and the significant developments in understanding the gene content of Hsa21. Moreover, we discuss future research directions in light of new technologies. In particular, the use of chromosome engineering to generate new trisomic mouse models and large-scale studies of genotype–phenotype relationships in patients are likely to significantly contribute to the future understanding of DS.
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Affiliation(s)
- Frances K Wiseman
- Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London, UK.
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77
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Effect of microglia activation on dopaminergic neuronal injury induced by manganese, and its possible mechanism. Neurotox Res 2009; 16:42-9. [PMID: 19526297 DOI: 10.1007/s12640-009-9045-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 12/08/2008] [Accepted: 12/08/2008] [Indexed: 10/20/2022]
Abstract
Manganese (Mn) is an essential trace element. It is known to have various functions, such as participating in enzymatic synthesis, and promoting hematopoiesis. On the other hand, it can cause toxic injury upon excess intake. However, toxic effects and its mechanism on glial cells are unclear. In the present study, we demonstrated that MnCl(2) can activate microglia, and that this can cause dopaminergic neuronal injury. Investigation of the underlying mechanisms showed that inducible nitric oxide synthase (iNOS), tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) was induced and highly expressed following Mn treatment. Moreover, pretreatment with S-methylisothiourea (SMT. iNOS inhibitor), Mn-induced iNOS expression and dopaminergic neuronal injury were partly reverse. Pretreatment with minocycline (microglia activation inhibitor), Mn-induced activation of microglia and dopaminergic neuronal injury was partly reverse. Taken together, our results showed that Mn can cause microglia activation, which can up-regulate the level of IL-1beta, TNF-alpha and iNOS, and these inflammatory factors can cause dopaminergic neuronal injury. SMT and minocycline prevent Mn-induced dopaminergic neuronal injury.
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78
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Nag N, Baxter MG, Berger-Sweeney JE. Efficacy of a murine-p75-saporin immunotoxin for selective lesions of basal forebrain cholinergic neurons in mice. Neurosci Lett 2009; 452:247-51. [PMID: 19150485 DOI: 10.1016/j.neulet.2009.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 01/02/2009] [Indexed: 11/18/2022]
Abstract
Selective lesioning of cholinergic neurons in the basal forebrain provides a tool for examining the functional significance of cholinergic loss, which is associated with a number of developmental and neurodegenerative disorders. A new version of an immunotoxin (murine-p75NTR-saporin) was used to produce a selective loss of cholinergic neurons in the adult basal forebrain of the mouse. This new version of the toxin is significantly more potent and selective than a previously developed version. C57Bl/6J mice (n=30) were given 1 microL of either saline or murine-p75NTR-saporin (0.65 microg/microL or 1.3 microg/microL) into the lateral ventricles, and then sacrificed 10-12 days post-surgery for histological analysis. In contrast to results from the previous version of the toxin, survival of the toxin-treated mice was 100% at both doses. A complete loss of cholinergic neurons was seen in the medial septum (MS) with both doses, while a dose-dependent loss of cholinergic neurons was observed in the nucleus basalis magnocellularis (nBM). The lesions were associated with locomotor hypoactivity and anxiolytic-type behavioral effects. These studies describe the efficacy and selectivity of this new version of murine-p75NTR-saporin, which may be used to provide insight into functional deficits that result from the loss of cholinergic neurons in the mouse basal forebrain.
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Affiliation(s)
- Nupur Nag
- Department of Biological Sciences, Wellesley College, Wellesley, MA 02481, USA
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79
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Orellana JA, Sáez PJ, Shoji KF, Schalper KA, Palacios-Prado N, Velarde V, Giaume C, Bennett MVL, Sáez JC. Modulation of brain hemichannels and gap junction channels by pro-inflammatory agents and their possible role in neurodegeneration. Antioxid Redox Signal 2009; 11:369-99. [PMID: 18816186 PMCID: PMC2713807 DOI: 10.1089/ars.2008.2130] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In normal brain, neurons, astrocytes, and oligodendrocytes, the most abundant and active cells express pannexins and connexins, protein subunits of two families forming membrane channels. Most available evidence indicates that in mammals endogenously expressed pannexins form only hemichannels and connexins form both gap junction channels and hemichannels. Whereas gap junction channels connect the cytoplasm of contacting cells and coordinate electric and metabolic activity, hemichannels communicate the intra- and extracellular compartments and serve as a diffusional pathway for ions and small molecules. A subthreshold stimulation by acute pathological threatening conditions (e.g., global ischemia subthreshold for cell death) enhances neuronal Cx36 and glial Cx43 hemichannel activity, favoring ATP release and generation of preconditioning. If the stimulus is sufficiently deleterious, microglia become overactivated and release bioactive molecules that increase the activity of hemichannels and reduce gap junctional communication in astroglial networks, depriving neurons of astrocytic protective functions, and further reducing neuronal viability. Continuous glial activation triggered by low levels of anomalous proteins expressed in several neurodegenerative diseases induce glial hemichannel and gap junction channel disorders similar to those of acute inflammatory responses triggered by ischemia or infectious diseases. These changes are likely to occur in diverse cell types of the CNS and contribute to neurodegeneration during inflammatory process.
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Affiliation(s)
- Juan A Orellana
- Departamento de Ciencias Fisiológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
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80
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Cholinergic degeneration and memory loss delayed by vitamin E in a Down syndrome mouse model. Exp Neurol 2008; 216:278-89. [PMID: 19135442 DOI: 10.1016/j.expneurol.2008.11.021] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2008] [Revised: 11/14/2008] [Accepted: 11/19/2008] [Indexed: 02/06/2023]
Abstract
Down syndrome (DS) individuals develop several neuropathological hallmarks seen in Alzheimer's disease, including cognitive decline and the early loss of cholinergic markers in the basal forebrain. These deficits are replicated in the Ts65Dn mouse, which contains a partial trisomy of murine chromosome 16, the orthologous genetic segment to human chromosome 21. Oxidative stress levels are elevated early in DS, and may contribute to the neurodegeneration seen in these individuals. We evaluated oxidative stress in Ts65Dn mice, and assessed the efficacy of long-term antioxidant supplementation on memory and basal forebrain pathology. We report that oxidative stress was elevated in the adult Ts65Dn brain, and that supplementation with the antioxidant vitamin E effectively reduced these markers. Also, Ts65Dn mice receiving vitamin E exhibited improved performance on a spatial working memory task and showed an attenuation of cholinergic neuron pathology in the basal forebrain. This study provides evidence that vitamin E delays onset of cognitive and morphological abnormalities in a mouse model of DS, and may represent a safe and effective treatment early in the progression of DS neuropathology.
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81
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Boger HA, Middaugh LD, Zaman V, Hoffer B, Granholm AC. Differential effects of the dopamine neurotoxin MPTP in animals with a partial deletion of the GDNF receptor, GFR alpha1, gene. Brain Res 2008; 1241:18-28. [PMID: 18822276 DOI: 10.1016/j.brainres.2008.09.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 08/30/2008] [Accepted: 09/08/2008] [Indexed: 11/19/2022]
Abstract
Glial cell line-derived neurotrophic factor (GDNF), a member of the transforming growth factor beta (TGFbeta) superfamily, is a potent neurotrophic protein promoting the survival and maintenance of dopaminergic (DA) neurons in the substantia nigra during development and adulthood. DA neurons that project to the striatum in the nigrostriatal pathway express GDNF receptors, GFR alpha1. The purpose of this study was to determine whether these neurons are especially sensitive to neurotoxic insults. Therefore, we examined effects of the dopaminergic toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on locomotion and DA neurons in 26-month-old male GFR alpha1 heterozygous (GFR alpha1(+/-)) mice compared to aged-matched wild-type (WT) littermates. MPTP gave rise to increased locomotion, regardless of genotype, while GFR alpha1(+/-) mice treated with saline exhibited lower spontaneous locomotion, compared to WT mice. Moreover, GFR alpha1(+/-) saline mice had fewer TH-positive neurons, greater expression of inflammatory markers (CD45 immunostaining and phosphorylated p38 MAPK) in the nigra, and reduced striatal TH staining. MPTP exacerbated these effects, with the lowest density of striatal TH and highest density of nigral CD45 and phospho-p38 MAPK immunoreactivity observed in GFR alpha1(+/-) mice. The findings point to increased sensitivity of the DAergic system with age and neurotoxic exposure as a result of a genetic reduction of GFR alpha1.
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Affiliation(s)
- Heather A Boger
- Department of Neurosciences, Center on Aging, Medical University of South Carolina, Charleston, SC 29425, USA.
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82
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Granholm AC, Bimonte-Nelson HA, Moore AB, Nelson ME, Freeman LR, Sambamurti K. Effects of a saturated fat and high cholesterol diet on memory and hippocampal morphology in the middle-aged rat. J Alzheimers Dis 2008; 14:133-45. [PMID: 18560126 DOI: 10.3233/jad-2008-14202] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Diets rich in cholesterol and/or saturated fats have been shown to be detrimental to cognitive performance. Therefore, we fed a cholesterol (2%) and saturated fat (hydrogenated coconut oil, Sat Fat 10%) diet to 16-month old rats for 8 weeks to explore the effects on the working memory performance of middle-aged rats. Lipid profiles revealed elevated plasma triglycerides, total cholesterol, HDL, and LDL for the Sat-Fat group as compared to an iso-caloric control diet (12% soybean oil). Weight gain and food consumption were similar in both groups. Sat-Fat treated rats committed more working memory errors in the water radial arm maze, especially at higher memory loads. Cholesterol, amyloid-beta peptide of 40 (Abeta40) or 42 (Abeta42) residues, and nerve growth factor in cortical regions was unaffected, but hippocampal Map-2 staining was reduced in rats fed a Sat-Fat diet, indicating a loss of dendritic integrity. Map-2 reduction correlated with memory errors. Microglial activation, indicating inflammation and/or gliosis, was also observed in the hippocampus of Sat-Fat fed rats. These data suggest that saturated fat, hydrogenated fat and cholesterol can profoundly impair memory and hippocampal morphology.
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Affiliation(s)
- Ann-Charlotte Granholm
- Department of Neurosciences and the Center on Aging, Medical University of South Carolina, Charleston, SC 29425, USA.
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83
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Stefanova N, Reindl M, Neumann M, Kahle PJ, Poewe W, Wenning GK. Microglial activation mediates neurodegeneration related to oligodendroglial alpha-synucleinopathy: implications for multiple system atrophy. Mov Disord 2008; 22:2196-203. [PMID: 17853477 DOI: 10.1002/mds.21671] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The role of microglial activation in multiple system atrophy (MSA) was investigated in a transgenic mouse model featuring oligodendroglial alpha-synuclein inclusions and loss of midbrain dopaminergic neurons by means of histopathology and morphometric analysis. Our findings demonstrate early progressive microglial activation in substantia nigra pars compacta (SNc) associated with increased expression of iNOS and correlating with dopaminergic neuronal loss. Suppression of microglial activation by early long-term minocycline treatment protected dopaminergic SNc neurons. The results suggest that oligodendroglial overexpression of alpha-synuclein may induce neuroinflammation related to nitrosive stress which is likely to contribute to neurodegeneration in MSA. Further, we detected increased toll-like receptor 4 immunoreactivity in both transgenic mice and MSA brains indicating a possible signaling pathway in MSA which needs to be further studied as a candidate target for neuroprotective interventions.
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Affiliation(s)
- Nadia Stefanova
- Clinical Neurobiology Unit, Neurodegeneration Research Laboratory, Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
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84
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Gordon PH, Moore DH, Miller RG, Florence JM, Verheijde JL, Doorish C, Hilton JF, Spitalny GM, MacArthur RB, Mitsumoto H, Neville HE, Boylan K, Mozaffar T, Belsh JM, Ravits J, Bedlack RS, Graves MC, McCluskey LF, Barohn RJ, Tandan R. Efficacy of minocycline in patients with amyotrophic lateral sclerosis: a phase III randomised trial. Lancet Neurol 2007; 6:1045-53. [PMID: 17980667 DOI: 10.1016/s1474-4422(07)70270-3] [Citation(s) in RCA: 470] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Minocycline has anti-apoptotic and anti-inflammatory effects in vitro, and extends survival in mouse models of some neurological conditions. Several trials are planned or are in progress to assess whether minocycline slows human neurodegeneration. We aimed to test the efficacy of minocycline as a treatment for amyotrophic lateral sclerosis (ALS). METHODS We did a multicentre, randomised placebo-controlled phase III trial. After a 4-month lead-in phase, 412 patients were randomly assigned to receive placebo or minocycline in escalating doses of up to 400 mg/day for 9 months. The primary outcome measure was the difference in rate of change in the revised ALS functional rating scale (ALSFRS-R). Secondary outcome measures were forced vital capacity (FVC), manual muscle testing (MMT), quality of life, survival, and safety. Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00047723. FINDINGS ALSFRS-R score deterioration was faster in the minocycline group than in the placebo group (-1.30 vs -1.04 units/month, 95% CI for difference -0.44 to -0.08; p=0.005). Patients on minocycline also had non-significant tendencies towards faster decline in FVC (-3.48 vs -3.01, -1.03 to 0.11; p=0.11) and MMT score (-0.30 vs -0.26, -0.08 to 0.01; p=0.11), and greater mortality during the 9-month treatment phase (hazard ratio=1.32, 95% CI 0.83 to 2.10; p=0.23) than did patients on placebo. Quality-of-life scores did not differ between the treatment groups. Non-serious gastrointestinal and neurological adverse events were more common in the minocycline group than in the placebo group, but these events were not significantly related to the decline in ALSFRS-R score. INTERPRETATION Our finding that minocycline has a harmful effect on patients with ALS has implications for trials of minocycline in patients with other neurological disorders, and for how potential neuroprotective agents are screened for use in patients with ALS.
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Affiliation(s)
- Paul H Gordon
- Department of Neurology, Columbia University, New York, NY, USA.
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85
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Choi Y, Kim HS, Shin KY, Kim EM, Kim M, Kim HS, Park CH, Jeong YH, Yoo J, Lee JP, Chang KA, Kim S, Suh YH. Minocycline attenuates neuronal cell death and improves cognitive impairment in Alzheimer's disease models. Neuropsychopharmacology 2007; 32:2393-404. [PMID: 17406652 DOI: 10.1038/sj.npp.1301377] [Citation(s) in RCA: 209] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Minocycline is a semi-synthetic tetracycline antibiotic that effectively crosses the blood-brain barrier. Minocycline has been reported to have significant neuroprotective effects in models of cerebral ischemia, traumatic brain injury, amyotrophic lateral sclerosis, and Huntington's and Parkinson's diseases. In this study, we demonstrate that minocycline has neuroprotective effects in in vitro and in vivo Alzheimer's disease models. Minocycline was found to attenuate the increases in the phosphorylation of double-stranded RNA-dependent serine/threonine protein kinase, eukaryotic translation initiation factor-2 alpha and caspase 12 activation induced by amyloid beta peptide1-42 treatment in NGF-differentiated PC 12 cells. In addition, increases in the phosphorylation of eukaryotic translation initiation factor-2 alpha were attenuated by administration of minocycline in Tg2576 mice, which harbor mutated human APP695 gene including the Swedish double mutation and amyloid beta peptide(1-42)-infused rats. We found that minocycline administration attenuated deficits in learning and memory in amyloid beta peptide(1-42)-infused rats. Increased phosphorylated state of eukaryotic translation initiation factor-2 alpha is observed in Alzheimer's disease patients' brains and may result in impairment of cognitive functions in Alzheimer's disease patients by decreasing the efficacy of de novo protein synthesis required for synaptic plasticity. On the basis of these results, minocycline may prove to be a good candidate as an effective therapeutic agent for Alzheimer's disease.
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Affiliation(s)
- Yoori Choi
- Department of Pharmacology, College of Medicine, National Creative Research Initiative Center for Alzheimer's Dementia and Neuroscience Research Institute, MRC, Seoul National University, Seoul, South Korea
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86
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Quilter CR, Blott SC, Wilson AE, Bagga MR, Sargent CA, Oliver GL, Southwood OI, Gilbert CL, Mileham A, Affara NA. Porcine maternal infanticide as a model for puerperal psychosis. Am J Med Genet B Neuropsychiatr Genet 2007; 144B:862-8. [PMID: 17503476 DOI: 10.1002/ajmg.b.30529] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Childbirth is a period of substantial rapid biological and psychological change and a wide range of psychotic disorders can occur ranging from mild 'baby blues' to severe episodes of psychotic illnesses. Puerperal psychosis is the most extreme form of postnatal psychosis, occurring in 1 in 1,000 births. In this study, we have used the pig as an animal model for human postnatal psychiatric illness. Our aim was to identify quantitative trait loci (QTL) associated with maternal (infanticide) sow aggression. This is defined by sows attacking and killing their own newborn offspring, within 24 hr of birth. An affected sib pair whole genome linkage analysis was carried out with 80 microsatellite markers covering the 18 porcine autosomes and the X chromosome, with the aim of identifying chromosomal regions responsible for this abnormal behavior. Analysis was carried out using the non-parametric linkage test of Whittemore and Halpern, as implemented in the Merlin software. The results identified 4 QTL mapping on Sus scrofa chromosomes 2 (SSC2), 10 (SSC10), and X (SSCX). The peak regions of these QTL are syntenic to HSA 5q14.3-15, 1q32, Xpter-Xp2.1, and Xq2.4-Xqter, respectively. Several potential candidate genes lie in these regions in addition to relevant abnormal behavioral QTL, found in humans and rodents.
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Affiliation(s)
- Claire R Quilter
- Human Molecular Genetics Group, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, UK.
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Kielian T, Esen N, Liu S, Phulwani NK, Syed MM, Phillips N, Nishina K, Cheung AL, Schwartzman JD, Ruhe JJ. Minocycline modulates neuroinflammation independently of its antimicrobial activity in staphylococcus aureus-induced brain abscess. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 171:1199-214. [PMID: 17717149 PMCID: PMC1988870 DOI: 10.2353/ajpath.2007.070231] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Minocycline exerts beneficial immune modulatory effects in several noninfectious neurodegenerative disease models; however, its potential to influence the host immune response during central nervous system bacterial infections, such as brain abscess, has not yet been investigated. Using a minocycline-resistant strain of Staphylococcus aureus to dissect the antibiotic's bacteriostatic versus immune modulatory effects in a mouse experimental brain abscess model, we found that minocycline significantly reduced mortality rates within the first 24 hours following bacterial exposure. This protection was associated with a transient decrease in the expression of several proinflammatory mediators, including interleukin-1beta and CCL2 (MCP-1). Minocycline was also capable of protecting the brain parenchyma from necrotic damage as evident by significantly smaller abscesses in minocycline-treated mice. In addition, minocycline exerted anti-inflammatory effects when administered as late as 3 days following S. aureus infection, which correlated with a significant decrease in brain abscess size. Finally, minocycline was capable of partially attenuating S. aureus-dependent microglial and astrocyte activation. Therefore, minocycline may afford additional therapeutic benefits extending beyond its antimicrobial activity for the treatment of central nervous system infectious diseases typified by a pathogenic inflammatory component through its ability to balance beneficial versus detrimental inflammation.
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Affiliation(s)
- Tammy Kielian
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, 4301 W. Markham St., Slot 846, Little Rock, AR 72205, USA.
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88
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Fan R, Xu F, Previti ML, Davis J, Grande AM, Robinson JK, Van Nostrand WE. Minocycline reduces microglial activation and improves behavioral deficits in a transgenic model of cerebral microvascular amyloid. J Neurosci 2007; 27:3057-63. [PMID: 17376966 PMCID: PMC6672462 DOI: 10.1523/jneurosci.4371-06.2007] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cerebral microvascular amyloid beta protein (Abeta) deposition and associated neuroinflammation is increasingly recognized as an important component leading to cognitive impairment in Alzheimer's disease and related cerebral amyloid angiopathy disorders. Transgenic mice expressing the vasculotropic Dutch/Iowa (E693Q/D694N) mutant human Abeta precursor protein in brain (Tg-SwDI) accumulate abundant cerebral microvascular fibrillar amyloid deposits and exhibit robust neuroinflammation. In the present study, we investigated the effect of the anti-inflammatory drug minocycline on Abeta accumulation, neuroinflammation, and behavioral deficits in Tg-SwDI mice. Twelve-month-old mice were treated with saline or minocycline by intraperitoneal injection every other day for a total of 4 weeks. During the final week of treatment, the mice were tested for impaired learning and memory. Brains were then harvested for biochemical and immunohistochemical analysis. Minocycline treatment did not alter the cerebral deposition of Abeta or the restriction of fibrillar amyloid to the cerebral microvasculature. Similarly, minocycline-treated Tg-SwDI mice exhibited no change in the levels of total Abeta, the ratios of Abeta40 and Abeta42, or the amounts of soluble, insoluble, or oligomeric Abeta compared with the saline-treated control Tg-SwDI mice. In contrast, the numbers of activated microglia and levels of interleukin-6 were significantly reduced in minocycline-treated Tg-SwDI mice compared with saline-treated Tg-SwDI mice. In addition, there was a significant improvement in behavioral performance of the minocycline-treated Tg-SwDI mice. These finding suggest that anti-inflammatory treatment targeted for cerebral microvascular amyloid-induced microglial activation can improve cognitive deficits without altering the accumulation and distribution of Abeta.
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89
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Korniychuk E, Dempster JM, O'Connor E, Alexander JS, Kelley RE, Kenner M, Menon U, Misra V, Hoque R, Gonzalez-Toledo E, Schwendimann RN, Smith S, Minagar A. Evolving Therapies For Multiple Sclerosis. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 79:571-88. [PMID: 17531859 DOI: 10.1016/s0074-7742(07)79025-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The introduction of immunomodulatory and immunosuppressive agents for treatment of multiple sclerosis (MS) has forever altered the natural course of this incurable and disabling neurodegenerative disorder. Despite early diagnosis of relapsing-remitting MS and early initiation of therapy, patients still experience breakthrough relapses and progression of their underlying MS pathology. The imperfect effectiveness, side effects, and toxicity of these agents, emphasize the necessity for development of more effective medications with less adverse events. This chapter presents readers with the most current information on the nature, mechanism(s) of action, and side effects of the most promising experimental agents currently under clinical trials. Some of the agents now at different stages of clinical trial have emerged as both safe and promising. The understanding of MS etiology will lead to the development of increasingly specific, safer, and effective treatments for MS by neuroscientists and neurologists.
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Affiliation(s)
- Elena Korniychuk
- Department of Neurology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71103, USA
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90
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Fodale V, Mafrica F, Caminiti V, Grasso G. The cholinergic system in Down's syndrome. JOURNAL OF INTELLECTUAL DISABILITIES : JOID 2006; 10:261-74. [PMID: 16916850 DOI: 10.1177/1744629506067615] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The cholinergic system is one of the most important modulatory neurotransmitter systems in the brain. Alterations of the transmission communicators are accompanied by reduction of the cortical activity, which is associated with a learning and memory deficit. Down's syndrome is a pathological condition characterized by a high number of abnormalities that involve the brain. The cholinergic system is involved in alterations of the neurological system such as severe learning difficulties. To explain these alterations, important results are obtained from studies about murine trisomy 16 (animal model of Down's syndrome). The results obtained provide useful elements in the improvement of knowledge about the neurological and neurotransmissional alterations that are responsible for the neurobiological characteristics of Down's syndrome. These data potentially justify, in these patients, the therapeutic use of drugs that are principally administered to improve the severe learning difficulties of people with Alzheimer's disease, and suggest a trend which generates a hypothesis worthy of further exploration.
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Affiliation(s)
- Vincenzo Fodale
- Department of Neurosciences, Psychiatric and Anesthesiological Sciences, University of Messina, Policlinico Universitario G Martino, Via C Valeria, Messina, Italy.
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91
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Quintero EM, Willis L, Singleton R, Harris N, Huang P, Bhat N, Granholm AC. Behavioral and morphological effects of minocycline in the 6-hydroxydopamine rat model of Parkinson's disease. Brain Res 2006; 1093:198-207. [PMID: 16712819 DOI: 10.1016/j.brainres.2006.03.104] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 03/17/2006] [Accepted: 03/20/2006] [Indexed: 12/21/2022]
Abstract
The neuropathology in many neurodegenerative diseases is mediated by inflammatory cascades that influence neuronal dysfunction and death. Minocycline reduces the neurodegeneration observed in various models of Parkinson's. We exploited the unilateral 6-hydroxydopamine (6-OHDA) lesion model to assess the effect of minocycline on related neurodegeneration. Thirty Fisher 344 rats were divided into three daily treatment groups: (1) after: 45 mg/kg of minocycline beginning 24 h after lesioning; (2) before: 45 mg/kg of minocycline beginning 3 days before 6-OHDA lesioning; (3) control: corresponding saline-treated controls. Animals were assessed for apomorphine-induced rotations for 4 weeks. A longitudinal model for repeated measures showed that both after and before groups had significantly lower rotations than controls (P < 0.001 for both comparisons). Pair-wise group comparisons showed that the before animals rotated less compared to controls (mean rotations: 164 +/- 38 versus 386 +/- 49, respectively, P = 0.001). After animals also rotated significantly less then controls (mean rotations: 125 +/- 41 versus 386 +/- 49, respectively, P < 0.001). Animals receiving minocycline displayed reduced tyrosine hydroxylase-positive cell loss in the lesioned nigra versus contralateral nonlesioned nigra, compared to controls (mean differences: 5065 for after, 3550 for before, and 6483 for controls; P = 0.158 for after versus controls, P = 0.019 for before versus controls). The remaining lesioned nigral cells of both minocycline-treated groups were larger than controls, with the most robust cell size and fiber density observed in the after group. These data suggest that the therapeutic potential of minocycline may depend on the time of drug administration relative to neuropathogenic event.
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Affiliation(s)
- Elias Matthew Quintero
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Suite 403, Charleston, SC 29425, USA.
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92
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Harashima C, Jacobowitz DM, Witta J, Borke RC, Best TK, Siarey RJ, Galdzicki Z. Abnormal expression of the G-protein-activated inwardly rectifying potassium channel 2 (GIRK2) in hippocampus, frontal cortex, and substantia nigra of Ts65Dn mouse: a model of Down syndrome. J Comp Neurol 2006; 494:815-33. [PMID: 16374808 PMCID: PMC2929960 DOI: 10.1002/cne.20844] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ts65Dn, a mouse model of Down syndrome (DS), demonstrates abnormal hippocampal synaptic plasticity and behavioral abnormalities related to spatial learning and memory. The molecular mechanisms leading to these impairments have not been identified. In this study, we focused on the G-protein-activated inwardly rectifying potassium channel 2 (GIRK2) gene that is highly expressed in the hippocampus region. We studied the expression pattern of GIRK subunits in Ts65Dn and found that GIRK2 was overexpressed in all analyzed Ts65Dn brain regions. Interestingly, elevated levels of GIRK2 protein in the Ts65Dn hippocampus and frontal cortex correlated with elevated levels of GIRK1 protein. This suggests that heteromeric GIRK1-GIRK2 channels are overexpressed in Ts65Dn hippocampus and frontal cortex, which could impair excitatory input and modulate spike frequency and synaptic kinetics in the affected regions. All GIRK2 splicing isoforms examined were expressed at higher levels in the Ts65Dn in comparison to the diploid hippocampus. The pattern of GIRK2 expression in the Ts65Dn mouse brain revealed by in situ hybridization and immunohistochemistry was similar to that previously reported in the rodent brain. However, in the Ts65Dn mouse a strong immunofluorescent staining of GIRK2 was detected in the lacunosum molecular layer of the CA3 area of the hippocampus. In addition, tyrosine hydroxylase containing dopaminergic neurons that coexpress GIRK2 were more numerous in the substantia nigra compacta and ventral tegmental area in the Ts65Dn compared to diploid controls. In summary, the regional localization and the increased brain levels coupled with known function of the GIRK channel may suggest an important contribution of GIRK2 containing channels to Ts65Dn and thus to DS neurophysiological phenotypes.
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Affiliation(s)
- Chie Harashima
- Department of Anatomy, Physiology and Genetics, USUHS School of Medicine, Bethesda, MD
| | - David M. Jacobowitz
- Department of Anatomy, Physiology and Genetics, USUHS School of Medicine, Bethesda, MD
- Laboratory of Clinical Science, NIMH, Bethesda, MD
| | - Jassir Witta
- Department of Pharmacology, USUHS School of Medicine, Bethesda, MD
| | - Rosemary C. Borke
- Department of Anatomy, Physiology and Genetics, USUHS School of Medicine, Bethesda, MD
- Neuroscience Program, USUHS School of Medicine, Bethesda, MD
| | - Tyler K. Best
- Neuroscience Program, USUHS School of Medicine, Bethesda, MD
| | - Richard J. Siarey
- Department of Anatomy, Physiology and Genetics, USUHS School of Medicine, Bethesda, MD
| | - Zygmunt Galdzicki
- Department of Anatomy, Physiology and Genetics, USUHS School of Medicine, Bethesda, MD
- Neuroscience Program, USUHS School of Medicine, Bethesda, MD
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93
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Microglia Biology in Health and Disease. J Neuroimmune Pharmacol 2006; 1:127-37. [DOI: 10.1007/s11481-006-9015-5] [Citation(s) in RCA: 343] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 02/15/2006] [Indexed: 12/21/2022]
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94
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Contestabile A, Fila T, Bartesaghi R, Contestabile A, Ciani E. Choline acetyltransferase activity at different ages in brain of Ts65Dn mice, an animal model for Down's syndrome and related neurodegenerative diseases. J Neurochem 2006; 97:515-26. [PMID: 16539660 DOI: 10.1111/j.1471-4159.2006.03769.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ts65Dn mice, trisomic for a portion of chromosome 16 segmentally homologous to human chromosome 21, are an animal model for Down's syndrome and related neurodegenerative diseases, such as dementia of the Alzheimer type. In these mice, cognitive deficits and alterations in number of basal forebrain cholinergic neurons have been described. We have measured in Ts65Dn mice the catalytic activity of the cholinergic marker, choline acetyltransferase (ChAT), as well as the activity of the acetylcholine-degrading enzyme acetylcholinesterase (AChE), in the hippocampus and in cortical targets of basal forebrain cholinergic neurons. In mice aged 10 months, ChAT activity was significantly higher in Ts65Dn mice, compared to 2N animals, in the hippocampus, olfactory bulb, olfactory cortex, pre-frontal cortex, but not in other neocortical regions. At 19 months of age, on the other hand, no differences in ChAT activity were found. Thus, alterations of ChAT activity in these forebrain areas seem to recapitulate those recently described in patients scored as cases of mild cognitive impairment or mild Alzheimer's disease. Other neurochemical markers putatively associated with the disease progression, such as those implicating astrocytic hyperactivity and overproduction of amyloid precursor protein family, were preferentially found altered in some brain regions at the oldest age examined (19 months).
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95
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Dierssen M, Ortiz-Abalia J, Arqué G, de Lagrán MM, Fillat C. Pitfalls And Hopes in Down Syndrome Therapeutic Approaches: In the Search for Evidence-Based Treatments. Behav Genet 2006; 36:454-68. [PMID: 16520905 DOI: 10.1007/s10519-006-9050-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 07/17/2005] [Indexed: 11/26/2022]
Abstract
Trisomy 21 or Down syndrome (DS) is a complex syndrome, of genetic origin with multiple and variable neurobiological and neuropsychological manifestations. DS patients have consistent signs of brain damage along their lives, but understanding the biology of DS is complicated due to the extraordinary heterogeneity of the phenotypic signs. Thus, treatment of DS mental retardation poses significant challenges for clinicians and scientists. The review addresses the classical pharmacological and environmental treatments and also critically reviews the new possibilities that are emerging from the exciting advances in gene or cell therapy. We describe some of the most recent developments in the field and give a sense of the prospects for future prevention and therapy.
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Affiliation(s)
- Mara Dierssen
- Genes and Disease Program, Genomic Regulation Center, (CRG-UPF), Barcelona Biomedical Research Park, Spain
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96
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Stack EC, Smith KM, Ryu H, Cormier K, Chen M, Hagerty SW, Del Signore SJ, Cudkowicz ME, Friedlander RM, Ferrante RJ. Combination therapy using minocycline and coenzyme Q10 in R6/2 transgenic Huntington's disease mice. Biochim Biophys Acta Mol Basis Dis 2006; 1762:373-80. [PMID: 16364609 DOI: 10.1016/j.bbadis.2005.11.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 11/03/2005] [Accepted: 11/07/2005] [Indexed: 10/25/2022]
Abstract
Huntington's disease (HD) is a fatal neurodegenerative disorder of genetic origin with no known therapeutic intervention that can slow or halt disease progression. Transgenic murine models of HD have significantly improved the ability to assess potential therapeutic strategies. The R6/2 murine model of HD, which recapitulates many aspects of human HD, has been used extensively in pre-clinical HD therapeutic treatment trials. Of several potential therapeutic candidates, both minocycline and coenzyme Q10 (CoQ10) have been demonstrated to provide significant improvement in the R6/2 mouse. Given the specific cellular targets of each compound, and the broad array of abnormalities thought to underlie HD, we sought to assess the effects of combined minocycline and CoQ10 treatment in the R6/2 mouse. Combined minocycline and CoQ10 therapy provided an enhanced beneficial effect, ameliorating behavioral and neuropathological alterations in the R6/2 mouse. Minocycline and CoQ10 treatment significantly extended survival and improved rotarod performance to a greater degree than either minocycline or CoQ10 alone. In addition, combined minocycline and CoQ10 treatment attenuated gross brain atrophy, striatal neuron atrophy, and huntingtin aggregation in the R6/2 mice relative to individual treatment. These data suggest that combined minocycline and CoQ10 treatment may offer therapeutic benefit to patients suffering from HD.
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Affiliation(s)
- Edward C Stack
- Geriatric Research Education and Clinical Center, Bedford VA Medical Center, Bedford, MA 01730, USA
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97
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98
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Hellstrom IC, Danik M, Luheshi GN, Williams S. Chronic LPS exposure produces changes in intrinsic membrane properties and a sustained IL-beta-dependent increase in GABAergic inhibition in hippocampal CA1 pyramidal neurons. Hippocampus 2005; 15:656-64. [PMID: 15889405 DOI: 10.1002/hipo.20086] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Chronic inflammation has been reported to be a significant factor in the induction and progression of a number of chronic neurological disorders including Alzheimer's disease and Down syndrome. It is believed that inflammation may promote synaptic dysfunction, an effect that is mediated in part by pro-inflammatory cytokines such as interleukin-1beta (IL-1beta). However, the role of IL-1beta and other cytokines in synaptic transmission is still poorly understood. In this study, we have investigated how synaptic transmission and neuronal excitability in hippocampal pyramidal neurons are affected by chronic inflammation induced by exposing organotypic slices to the bacterial cell-wall product lipopolysaccharide (LPS). We report that CA1 pyramidal neurons recorded in whole cell from slices previously exposed to LPS for 7 days had resting membrane potential and action potential properties similar to those of the controls. However, they had significantly lower membrane resistance and a more elevated action potential threshold, and displayed a slower frequency of action potential discharge. Moreover, the amplitude of pharmacologically isolated postsynaptic gamma-aminobutyric acid (GABA)ergic potentials, but not excitatory glutamatergic postsynaptic potentials, was significantly larger following chronic LPS exposure. Interestingly, co-incubation of the IL-1 receptor antagonist (IL-1Ra) concurrently with LPS prevented the increase in GABAergic transmission, but not the reduction in intrinsic neuronal excitability. Finally, we confirmed that LPS dramatically increased IL-1beta, and IL-1beta-dependent IL-6 levels in the culture medium for 2 days before returning to baseline. We conclude that CA1 pyramidal neurons in slices chronically exposed to LPS show a persistent decrease in excitability due to a combined decrease in intrinsic membrane excitability and an enhancement in synaptic GABAergic input, the latter being dependent on IL-1beta. Therefore, chronic inflammation in hippocampus produces IL-1beta-dependent and -independent effects in neuronal and synaptic function that could contribute significantly to cognitive disturbances.
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Affiliation(s)
- Ian C Hellstrom
- Douglas Hospital Research Centre, McGill University, Montréal, Québec, Canada
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99
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Giuliani F, Fu SA, Metz LM, Yong VW. Effective combination of minocycline and interferon-β in a model of multiple sclerosis. J Neuroimmunol 2005; 165:83-91. [PMID: 15958276 DOI: 10.1016/j.jneuroim.2005.04.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 04/22/2005] [Indexed: 11/22/2022]
Abstract
The objective of the current study was to investigate whether minocycline improves the effect of an existing multiple sclerosis (MS) medication, interferon-beta, on experimental autoimmune encephalomyelitis (EAE) in mice. When used at sub-optimal doses, neither medication affected EAE but their combination at these doses led to the significant alleviation of EAE disease severity scores and histological outcomes. In culture, the toxicity of T cells to neurons was alleviated by their prior exposure to minocycline or interferon-beta and their combination further attenuated neuronal death. Collectively, these results suggest the utility of the combination of minocycline and interferon-beta in MS.
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MESH Headings
- Adult
- Animals
- Cell Death/immunology
- Cell Proliferation/drug effects
- Cells, Cultured
- Coculture Techniques
- Cytotoxicity, Immunologic
- Disease Models, Animal
- Drug Therapy, Combination
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Humans
- Interferon Type I/administration & dosage
- Interferon Type I/pharmacology
- Interferon Type I/therapeutic use
- Lymphocyte Activation/drug effects
- Lymphocyte Activation/immunology
- Mice
- Minocycline/administration & dosage
- Minocycline/pharmacology
- Minocycline/therapeutic use
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
- Neurons/drug effects
- Neurons/immunology
- Neurons/pathology
- Recombinant Proteins
- Severity of Illness Index
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/drug effects
- T-Lymphocyte Subsets/immunology
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Affiliation(s)
- Fabrizio Giuliani
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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