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Sharma V, Singh TG, Kaur A, Mannan A, Dhiman S. Brain-Derived Neurotrophic Factor: A Novel Dynamically Regulated Therapeutic Modulator in Neurological Disorders. Neurochem Res 2023; 48:317-339. [PMID: 36308619 DOI: 10.1007/s11064-022-03755-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 02/04/2023]
Abstract
The growth factor brain-derived neurotrophic factor (BDNF), and its receptor tropomyosin-related kinase receptor type B (TrkB) play an active role in numerous areas of the adult brain, where they regulate the neuronal activity, function, and survival. Upregulation and downregulation of BDNF expression are critical for the physiology of neuronal circuits and functioning in the brain. Loss of BDNF function has been reported in the brains of patients with neurodegenerative or psychiatric disorders. This article reviews the BDNF gene structure, transport, secretion, expression and functions in the brain. This article also implicates BDNF in several brain-related disorders, including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, major depressive disorder, schizophrenia, epilepsy and bipolar disorder.
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Affiliation(s)
- Veerta Sharma
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
| | - Thakur Gurjeet Singh
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India.
| | - Amarjot Kaur
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
| | - Ashi Mannan
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
| | - Sonia Dhiman
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
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2
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Li SH, Abd-Elrahman KS, Ferguson SS. Targeting mGluR2/3 for treatment of neurodegenerative and neuropsychiatric diseases. Pharmacol Ther 2022; 239:108275. [DOI: 10.1016/j.pharmthera.2022.108275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/23/2022] [Accepted: 08/23/2022] [Indexed: 10/15/2022]
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3
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Group II Metabotropic Glutamate Receptors Reduce Apoptosis and Regulate BDNF and GDNF Levels in Hypoxic-Ischemic Injury in Neonatal Rats. Int J Mol Sci 2022; 23:ijms23137000. [PMID: 35806000 PMCID: PMC9266366 DOI: 10.3390/ijms23137000] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 12/13/2022] Open
Abstract
Birth asphyxia causes brain injury in neonates, but a fully successful treatment has yet to be developed. This study aimed to investigate the effect of group II mGlu receptors activation after experimental birth asphyxia (hypoxia-ischemia) on the expression of factors involved in apoptosis and neuroprotective neurotrophins. Hypoxia-ischemia (HI) on 7-day-old rats was used as an experimental model. The effects of intraperitoneal application of mGluR2 agonist LY379268 (5 mg/kg) and the specific mGluR3 agonist NAAG (5 mg/kg) (1 h or 6 h after HI) on apoptotic processes and initiation of the neuroprotective mechanism were investigated. LY379268 and NAAG applied shortly after HI prevented brain damage and significantly decreased pro-apoptotic Bax and HtrA2/Omi expression, increasing expression of anti-apoptotic Bcl-2. NAAG or LY379268 applied at both times also decreased HIF-1α formation. HI caused a significant decrease in BDNF concentration, which was restored after LY379268 or NAAG administration. HI-induced increase in GDNF concentration was decreased after administration of LY379268 or NAAG. Our results show that activation of mGluR2/3 receptors shortly after HI prevents brain damage by the inhibition of excessive glutamate release and apoptotic damage decrease. mGluR2 and mGluR3 agonists produced comparable results, indicating that both receptors may be a potential target for early treatment in neonatal HI.
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4
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Wang H, Del Mar N, Deng Y, Reiner A. Rescue of BDNF expression by the thalamic parafascicular nucleus with chronic treatment with the mGluR2/3 agonist LY379268 may contribute to the LY379268 rescue of enkephalinergic striatal projection neurons in R6/2 Huntington's disease mice. Neurosci Lett 2021; 763:136180. [PMID: 34416343 DOI: 10.1016/j.neulet.2021.136180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/13/2021] [Accepted: 08/14/2021] [Indexed: 10/20/2022]
Abstract
We have found that daily subcutaneous injection with a maximum tolerated dose of the mGluR2/3 agonist LY379268 (20 mg/kg) beginning at 4 weeks of age dramatically improves the motor, neuronal and neurochemical phenotype in R6/2 mice, a rapidly progressing transgenic model of Huntington's disease (HD). We also previously showed that the benefit of daily LY379268 in R6/2 mice was associated with increases in corticostriatal brain-derived neurotrophic factor (BDNF), and in particular was associated with a reduction in enkephalinergic striatal projection neuron loss. In the present study, we show that daily LY379268 also rescues expression of BDNF by neurons of the thalamic parafascicular nucleus in R6/2 mice, which projects prominently to the striatum, and this increase too is linked to the rescue of enkephalinergic striatal neurons. Thus, LY379268 may protect enkephalinergic striatal projection neurons from loss by boosting BDNF production and delivery via both the corticostriatal and thalamostriatal projection systems. These results suggest that chronic treatment with mGluR2/3 agonists may represent an approach for slowing enkephalinergic neuron loss in HD, and perhaps progression in general.
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Affiliation(s)
- H Wang
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
| | - N Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
| | - Y Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
| | - A Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States; Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
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5
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Li SH, Colson TLL, Abd-Elrahman KS, Ferguson SS. mGluR2/3 Activation Improves Motor Performance and Reduces Pathology in heterozygous zQ175 Huntington's Disease Mice. J Pharmacol Exp Ther 2021; 379:74-84. [PMID: 34330748 DOI: 10.1124/jpet.121.000735] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/20/2021] [Indexed: 11/22/2022] Open
Abstract
Huntington's Disease (HD) is an autosomal dominant neurodegenerative disease that leads to progressive motor impairment with no available disease-modifying treatments. Current evidence indicates that exacerbated postsynaptic glutamate signaling in the striatum plays a key role in the pathophysiology of HD. However, it remains unclear whether reducing glutamate release can be an effective approach to slow the progression of HD. Here, we show that the activation of metabotropic glutamate receptors 2 and 3 (mGluR2/3), which inhibit presynaptic glutamate release, improves HD symptoms and pathology in heterozygous zQ175 knock-in mice. Treatment of both male and female zQ175 mice with the potent and selective mGluR2/3 agonist LY379268 for either 4 or 8 weeks improves both limb coordination and locomotor function in all mice. LY379268 also reduces mutant huntingtin aggregate formation, neuronal cell death, and microglia activation in the striatum of both male and female zQ175 mice. The reduction in mutant huntingtin protein correlates with the activation of a GSK3β-dependent autophagy pathway in male, but not female, zQ175 mice. Furthermore, LY379268 reduces both Akt and ERK1/2 phosphorylation in male zQ175 mice but increases both Akt and ERK1/2 phosphorylation in female zQ175 mice. Taken together, our results indicate that mGluR2/3 activation mitigates HD neuropathology in both male and female mice but is associated with the differential activation and inactivation of cell signaling pathways in heterozygous male and female zQ175 mice. This further highlights the need to take sex into consideration when developing future HD therapeutics. Significance Statement The mGluR2/3 agonist LY379268 improves motor impairments and reduces pathology in male and female zQ175 Huntington's mice. The beneficial outcomes of LY379268 treatment in Huntington's mice were mediated by divergent cell signalling pathways in both sexes. We provide evidence that mGluR2/3 agonists can be repurposed for the treatment of Huntington's disease and we emphasize the importance of investigating sex as a biological variable in preclinical disease modifying studies.
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6
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Deng Y, Wang H, Joni M, Sekhri R, Reiner A. Progression of basal ganglia pathology in heterozygous Q175 knock-in Huntington's disease mice. J Comp Neurol 2021; 529:1327-1371. [PMID: 32869871 PMCID: PMC8049038 DOI: 10.1002/cne.25023] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/07/2020] [Accepted: 08/26/2020] [Indexed: 12/29/2022]
Abstract
We used behavioral testing and morphological methods to detail the progression of basal ganglia neuron type-specific pathology and the deficits stemming from them in male heterozygous Q175 mice, compared to age-matched WT males. A rotarod deficit was not present in Q175 mice until 18 months, but increased open field turn rate (reflecting hyperkinesia) and open field anxiety were evident at 6 months. No loss of striatal neurons was seen out to 18 months, but ENK+ and DARPP32+ striatal perikarya were fewer by 6 months, due to diminished expression, with further decline by 18 months. No reduction in SP+ striatal perikarya or striatal interneurons was seen in Q175 mice at 18 months, but cholinergic interneurons showed dendrite attenuation by 6 months. Despite reduced ENK expression in indirect pathway striatal perikarya, ENK-immunostained terminals in globus pallidus externus (GPe) were more abundant at 6 months and remained so out to 18 months. Similarly, SP-immunostained terminals from striatal direct pathway neurons were more abundant in globus pallidus internus and substantia nigra at 6 months and remained so at 18 months. FoxP2+ arkypallidal GPe neurons and subthalamic nucleus neurons were lost by 18 months but not prototypical PARV+ GPe neurons or dopaminergic nigral neurons. Our results show that striatal projection neuron abnormalities and behavioral abnormalities reflecting them develop between 2 and 6 months of age in Q175 male heterozygotes, indicating early effects of the HD mutation. The striatal pathologies resemble those in human HD, but are less severe at 18 months than even in premanifest HD.
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Affiliation(s)
- Yunping Deng
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Hongbing Wang
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Marion Joni
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Radhika Sekhri
- Department of PathologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Anton Reiner
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
- Department of OphthalmologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
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7
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Etxeberria-Rekalde E, Alzola-Aldamizetxebarria S, Flunkert S, Hable I, Daurer M, Neddens J, Hutter-Paier B. Quantification of Huntington's Disease Related Markers in the R6/2 Mouse Model. Front Mol Neurosci 2021; 13:617229. [PMID: 33505246 PMCID: PMC7831778 DOI: 10.3389/fnmol.2020.617229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/10/2020] [Indexed: 12/12/2022] Open
Abstract
Huntington’s disease (HD) is caused by an expansion of CAG triplets in the huntingtin gene, leading to severe neuropathological changes that result in a devasting and lethal phenotype. Neurodegeneration in HD begins in the striatum and spreads to other brain regions such as cortex and hippocampus, causing motor and cognitive dysfunctions. To understand the signaling pathways involved in HD, animal models that mimic the human pathology are used. The R6/2 mouse as model of HD was already shown to present major neuropathological changes in the caudate putamen and other brain regions, but recently established biomarkers in HD patients were yet not analyzed in these mice. We therefore performed an in-depth analysis of R6/2 mice to establish new and highly translational readouts focusing on Ctip2 as biological marker for motor system-related neurons and translocator protein (TSPO) as a promising readout for early neuroinflammation. Our results validate already shown pathologies like mutant huntingtin aggregates, ubiquitination, and brain atrophy, but also provide evidence for decreased tyrosine hydroxylase and Ctip2 levels as indicators of a disturbed motor system, while vesicular acetyl choline transporter levels as marker for the cholinergic system barely change. Additionally, increased astrocytosis and activated microglia were observed by GFAP, Iba1 and TSPO labeling, illustrating, that TSPO is a more sensitive marker for early neuroinflammation compared to GFAP and Iba1. Our results thus demonstrate a high sensitivity and translational value of Ctip2 and TSPO as new marker for the preclinical evaluation of new compounds in the R6/2 mouse model of HD.
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Affiliation(s)
| | | | | | - Isabella Hable
- QPS Austria GmbH, Grambach, Austria.,Department of Health Studies, FH Joanneum University of Applied Sciences, Graz, Austria
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8
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Heikkinen T, Bragge T, Bhattarai N, Parkkari T, Puoliväli J, Kontkanen O, Sweeney P, Park LC, Munoz-Sanjuan I. Rapid and robust patterns of spontaneous locomotor deficits in mouse models of Huntington's disease. PLoS One 2020; 15:e0243052. [PMID: 33370315 PMCID: PMC7769440 DOI: 10.1371/journal.pone.0243052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 11/15/2020] [Indexed: 11/25/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by severe disruption of cognitive and motor functions, including changes in posture and gait. A number of HD mouse models have been engineered that display behavioral and neuropathological features of the disease, but gait alterations in these models are poorly characterized. Sensitive high-throughput tests of fine motor function and gait in mice might be informative in evaluating disease-modifying interventions. Here, we describe a hypothesis-free workflow that determines progressively changing locomotor patterns across 79 parameters in the R6/2 and Q175 mouse models of HD. R6/2 mice (120 CAG repeats) showed motor disturbances as early as at 4 weeks of age. Similar disturbances were observed in homozygous and heterozygous Q175 KI mice at 3 and 6 months of age, respectively. Interestingly, only the R6/2 mice developed forelimb ataxia. The principal components of the behavioral phenotypes produced two phenotypic scores of progressive postural instability based on kinematic parameters and trajectory waveform data, which were shared by both HD models. This approach adds to the available HD mouse model research toolbox and has a potential to facilitate the development of therapeutics for HD and other debilitating movement disorders with high unmet medical need.
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Affiliation(s)
| | - Timo Bragge
- Charles River Discovery Services, Kuopio, Finland
| | - Niina Bhattarai
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | | | | | | | | | - Larry C Park
- Naason Science Inc., Chungcheongbuk-do, South Korea.,CHDI Management/CHDI Foundation, Los Angeles, California, United States of America
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9
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Smith‐Dijak AI, Sepers MD, Raymond LA. Alterations in synaptic function and plasticity in Huntington disease. J Neurochem 2019; 150:346-365. [DOI: 10.1111/jnc.14723] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/28/2019] [Accepted: 05/08/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Amy I. Smith‐Dijak
- Graduate Program in Neuroscience the University of British Columbia Vancouver British Columbia Canada
- Department of Psychiatry and Djavad Mowafaghian Centre for Brain Health the University of British Columbia Vancouver British Columbia Canada
| | - Marja D. Sepers
- Department of Psychiatry and Djavad Mowafaghian Centre for Brain Health the University of British Columbia Vancouver British Columbia Canada
| | - Lynn A. Raymond
- Department of Psychiatry and Djavad Mowafaghian Centre for Brain Health the University of British Columbia Vancouver British Columbia Canada
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10
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Simmons DA. Modulating Neurotrophin Receptor Signaling as a Therapeutic Strategy for Huntington's Disease. J Huntingtons Dis 2018; 6:303-325. [PMID: 29254102 PMCID: PMC5757655 DOI: 10.3233/jhd-170275] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansions in the IT15 gene which encodes the huntingtin (HTT) protein. Currently, no treatments capable of preventing or slowing disease progression exist. Disease modifying therapeutics for HD would be expected to target a comprehensive set of degenerative processes given the diverse mechanisms contributing to HD pathogenesis including neuroinflammation, excitotoxicity, and transcription dysregulation. A major contributor to HD-related degeneration is mutant HTT-induced loss of neurotrophic support. Thus, neurotrophin (NT) receptors have emerged as therapeutic targets in HD. The considerable overlap between NT signaling networks and those dysregulated by mutant HTT provides strong theoretical support for this approach. This review will focus on the contributions of disrupted NT signaling in HD-related neurodegeneration and how targeting NT receptors to augment pro-survival signaling and/or to inhibit degenerative signaling may combat HD pathologies. Therapeutic strategies involving NT delivery, peptidomimetics, and the targeting of specific NT receptors (e.g., Trks or p75NTR), particularly with small molecule ligands, are discussed.
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Affiliation(s)
- Danielle A Simmons
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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11
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Reiner A, Deng Y. Disrupted striatal neuron inputs and outputs in Huntington's disease. CNS Neurosci Ther 2018; 24:250-280. [PMID: 29582587 PMCID: PMC5875736 DOI: 10.1111/cns.12844] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 12/22/2022] Open
Abstract
Huntington's disease (HD) is a hereditary progressive neurodegenerative disorder caused by a CAG repeat expansion in the gene coding for the protein huntingtin, resulting in a pathogenic expansion of the polyglutamine tract in the N-terminus of this protein. The HD pathology resulting from the mutation is most prominent in the striatal part of the basal ganglia, and progressive differential dysfunction and loss of striatal projection neurons and interneurons account for the progression of motor deficits seen in this disease. The present review summarizes current understanding regarding the progression in striatal neuron dysfunction and loss, based on studies both in human HD victims and in genetic mouse models of HD. We review evidence on early loss of inputs to striatum from cortex and thalamus, which may be the basis of the mild premanifest bradykinesia in HD, as well as on the subsequent loss of indirect pathway striatal projection neurons and their outputs to the external pallidal segment, which appears to be the basis of the chorea seen in early symptomatic HD. Later loss of direct pathway striatal projection neurons and their output to the internal pallidal segment account for the severe akinesia seen late in HD. Loss of parvalbuminergic striatal interneurons may contribute to the late dystonia and rigidity.
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Affiliation(s)
- Anton Reiner
- Department of Anatomy & NeurobiologyThe University of Tennessee Health Science CenterMemphisTNUSA
- Department of OphthalmologyThe University of Tennessee Health Science CenterMemphisTNUSA
| | - Yun‐Ping Deng
- Department of Anatomy & NeurobiologyThe University of Tennessee Health Science CenterMemphisTNUSA
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12
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Dragatsis I, Dietrich P, Ren H, Deng YP, Del Mar N, Wang HB, Johnson IM, Jones KR, Reiner A. Effect of early embryonic deletion of huntingtin from pyramidal neurons on the development and long-term survival of neurons in cerebral cortex and striatum. Neurobiol Dis 2017; 111:102-117. [PMID: 29274742 PMCID: PMC5821111 DOI: 10.1016/j.nbd.2017.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 11/07/2017] [Accepted: 12/19/2017] [Indexed: 12/12/2022] Open
Abstract
We evaluated the impact of early embryonic deletion of huntingtin (htt) from pyramidal neurons on cortical development, cortical neuron survival and motor behavior, using a cre-loxP strategy to inactivate the mouse htt gene (Hdh) in emx1-expressing cell lineages. Western blot confirmed substantial htt reduction in cerebral cortex of these Emx-httKO mice, with residual cortical htt in all likelihood restricted to cortical interneurons of the subpallial lineage and/or vascular endothelial cells. Despite the loss of htt early in development, cortical lamination was normal, as revealed by layer-specific markers. Cortical volume and neuron abundance were, however, significantly less than normal, and cortical neurons showed reduced brain-derived neurotrophic factor (BDNF) expression and reduced activation of BDNF signaling pathways. Nonetheless, cortical volume and neuron abundance did not show progressive age-related decline in Emx-httKO mice out to 24 months. Although striatal neurochemistry was normal, reductions in striatal volume and neuron abundance were seen in Emx-httKO mice, which were again not progressive. Weight maintenance was normal in Emx-httKO mice, but a slight rotarod deficit and persistent hyperactivity were observed throughout the lifespan. Our results show that embryonic deletion of htt from developing pallium does not substantially alter migration of cortical neurons to their correct laminar destinations, but does yield reduced cortical and striatal size and neuron numbers. The Emx-httKO mice were persistently hyperactive, possibly due to defects in corticostriatal development. Importantly, deletion of htt from cortical pyramidal neurons did not yield age-related progressive cortical or striatal pathology.
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Affiliation(s)
- I Dragatsis
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - P Dietrich
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - H Ren
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Y P Deng
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - N Del Mar
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - H B Wang
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - I M Johnson
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - K R Jones
- Department of Molecular, Cellular, & Developmental Biology, 347 UCB, University of Colorado, Boulder, CO 80309, United States
| | - A Reiner
- Department of Anatomy & Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States; Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN 38163, United States.
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13
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Dietrich P, Johnson IM, Alli S, Dragatsis I. Elimination of huntingtin in the adult mouse leads to progressive behavioral deficits, bilateral thalamic calcification, and altered brain iron homeostasis. PLoS Genet 2017; 13:e1006846. [PMID: 28715425 PMCID: PMC5536499 DOI: 10.1371/journal.pgen.1006846] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 07/31/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
Huntington's Disease (HD) is an autosomal dominant progressive neurodegenerative disorder characterized by cognitive, behavioral and motor dysfunctions. HD is caused by a CAG repeat expansion in exon 1 of the HD gene that is translated into an expanded polyglutamine tract in the encoded protein, huntingtin (HTT). While the most significant neuropathology of HD occurs in the striatum, other brain regions are also affected and play an important role in HD pathology. To date there is no cure for HD, and recently strategies aiming at silencing HTT expression have been initiated as possible therapeutics for HD. However, the essential functions of HTT in the adult brain are currently unknown and hence the consequence of sustained suppression of HTT expression is unpredictable and can potentially be deleterious. Using the Cre-loxP system of recombination, we conditionally inactivated the mouse HD gene homologue at 3, 6 and 9 months of age. Here we show that elimination of Htt expression in the adult mouse results in behavioral deficits, progressive neuropathological changes including bilateral thalamic calcification, and altered brain iron homeostasis.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
| | - Irudayam Maria Johnson
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
| | - Shanta Alli
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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14
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Wright DJ, Renoir T, Gray LJ, Hannan AJ. Huntington’s Disease: Pathogenic Mechanisms and Therapeutic Targets. ADVANCES IN NEUROBIOLOGY 2017; 15:93-128. [DOI: 10.1007/978-3-319-57193-5_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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15
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Bu W, Ren H, Deng Y, Del Mar N, Guley NM, Moore BM, Honig MG, Reiner A. Mild Traumatic Brain Injury Produces Neuron Loss That Can Be Rescued by Modulating Microglial Activation Using a CB2 Receptor Inverse Agonist. Front Neurosci 2016; 10:449. [PMID: 27766068 PMCID: PMC5052277 DOI: 10.3389/fnins.2016.00449] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/20/2016] [Indexed: 12/12/2022] Open
Abstract
We have previously reported that mild TBI created by focal left-side cranial blast in mice produces widespread axonal injury, microglial activation, and a variety of functional deficits. We have also shown that these functional deficits are reduced by targeting microglia through their cannabinoid type-2 (CB2) receptors using 2-week daily administration of the CB2 inverse agonist SMM-189. CB2 inverse agonists stabilize the G-protein coupled CB2 receptor in an inactive conformation, leading to increased phosphorylation and nuclear translocation of the cAMP response element binding protein (CREB), and thus bias activated microglia from a pro-inflammatory M1 to a pro-healing M2 state. In the present study, we showed that SMM-189 boosts nuclear pCREB levels in microglia in several brain regions by 3 days after TBI, by using pCREB/CD68 double immunofluorescent labeling. Next, to better understand the basis of motor deficits and increased fearfulness after TBI, we used unbiased stereological methods to characterize neuronal loss in cortex, striatum, and basolateral amygdala (BLA) and assessed how neuronal loss was affected by SMM-189 treatment. Our stereological neuron counts revealed a 20% reduction in cortical and 30% reduction in striatal neurons bilaterally at 2-3 months post blast, with SMM-189 yielding about 50% rescue. Loss of BLA neurons was restricted to the blast side, with 33% of Thy1+ fear-suppressing pyramidal neurons and 47% of fear-suppressing parvalbuminergic (PARV) interneurons lost, and Thy1-negative fear-promoting pyramidal neurons not significantly affected. SMM-189 yielded 50-60% rescue of Thy1+ and PARV neuron loss in BLA. Thus, fearfulness after mild TBI may result from the loss of fear-suppressing neuron types in BLA, and SMM-189 may reduce fearfulness by their rescue. Overall, our findings indicate that SMM-189 rescues damaged neurons and thereby alleviates functional deficits resulting from TBI, apparently by selectively modulating microglia to the beneficial M2 state. CB2 inverse agonists thus represent a promising therapeutic approach for mitigating neuroinflammation and neurodegeneration.
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Affiliation(s)
- Wei Bu
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Huiling Ren
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Yunping Deng
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Nobel Del Mar
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Natalie M. Guley
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Bob M. Moore
- Department of Pharmaceutical Sciences, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Marcia G. Honig
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology, University of Tennessee Health Science CenterMemphis, TN, USA
- Department of Ophthalmology, University of Tennessee Health Science CenterMemphis, TN, USA
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16
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Guley NH, Rogers JT, Del Mar NA, Deng Y, Islam RM, D'Surney L, Ferrell J, Deng B, Hines-Beard J, Bu W, Ren H, Elberger AJ, Marchetta JG, Rex TS, Honig MG, Reiner A. A Novel Closed-Head Model of Mild Traumatic Brain Injury Using Focal Primary Overpressure Blast to the Cranium in Mice. J Neurotrauma 2016; 33:403-22. [PMID: 26414413 PMCID: PMC4761824 DOI: 10.1089/neu.2015.3886] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mild traumatic brain injury (TBI) from focal head impact is the most common form of TBI in humans. Animal models, however, typically use direct impact to the exposed dura or skull, or blast to the entire head. We present a detailed characterization of a novel overpressure blast system to create focal closed-head mild TBI in mice. A high-pressure air pulse limited to a 7.5 mm diameter area on the left side of the head overlying the forebrain is delivered to anesthetized mice. The mouse eyes and ears are shielded, and its head and body are cushioned to minimize movement. This approach creates mild TBI by a pressure wave that acts on the brain, with minimal accompanying head acceleration-deceleration. A single 20-psi blast yields no functional deficits or brain injury, while a single 25-40 psi blast yields only slight motor deficits and brain damage. By contrast, a single 50-60 psi blast produces significant visual, motor, and neuropsychiatric impairments and axonal damage and microglial activation in major fiber tracts, but no contusive brain injury. This model thus reproduces the widespread axonal injury and functional impairments characteristic of closed-head mild TBI, without the complications of systemic or ocular blast effects or head acceleration that typically occur in other blast or impact models of closed-skull mild TBI. Accordingly, our model provides a simple way to examine the biomechanics, pathophysiology, and functional deficits that result from TBI and can serve as a reliable platform for testing therapies that reduce brain pathology and deficits.
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Affiliation(s)
- Natalie H. Guley
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Joshua T. Rogers
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Nobel A. Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Yunping Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Rafiqul M. Islam
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Anatomy and Histology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Lauren D'Surney
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Jessica Ferrell
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Bowei Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Jessica Hines-Beard
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, Tennessee
| | - Wei Bu
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Huiling Ren
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Andrea J. Elberger
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Tonia S. Rex
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, Tennessee
| | - Marcia G. Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, Tennessee
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, Tennessee
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17
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The group II metabotropic glutamate receptor agonist LY379268 reduces toluene-induced enhancement of brain-stimulation reward and behavioral disturbances. Psychopharmacology (Berl) 2015; 232:3259-68. [PMID: 26044619 PMCID: PMC4536139 DOI: 10.1007/s00213-015-3973-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 05/24/2015] [Indexed: 01/05/2023]
Abstract
RATIONALE Toluene, a widely abused solvent with demonstrated addictive potential in humans, hasbeen reported to negatively modulate N-methyl-D-aspartate receptors (NMDARs) and alter glutamatergicneurotransmission. The group II metabotropic glutamate receptor (mGluR) agonist LY379268 has beenshown to regulate glutamate release transmission and NMDAR function and block toluene-induced locomotorhyperactivity. However, remaining unknown is whether group II mGluRs are involved in the toluene-induced reward-facilitating effect and other behavioral manifestations. OBJECTIVES The present study evaluated the effects of LY379268 on toluene-induced reward enhancement, motor incoordination, recognition memory impairment, and social interaction deficits. RESULTS Our data demonstrated that LY379268 significantly reversed the toluene-induced lowering of intracranial self-stimulation (ICSS) thresholds and impairments in novel object recognition, rotarod performance, and social interaction with different potencies. CONCLUSIONS These results indicate a negative modulatory role of group II mGluRs in acute toluene-induced reward-facilitating and behavioral effects and suggest that group II mGluR agonists may have therapeutic potential for toluene addiction and the prevention of toluene intoxication caused by occupational or intentional exposure.
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18
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Kupferschmidt DA, Lovinger DM. Inhibition of presynaptic calcium transients in cortical inputs to the dorsolateral striatum by metabotropic GABA(B) and mGlu2/3 receptors. J Physiol 2015; 593:2295-310. [PMID: 25781000 DOI: 10.1113/jp270045] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/06/2015] [Indexed: 01/30/2023] Open
Abstract
Cortical inputs to the dorsolateral striatum (DLS) are dynamically regulated during skill learning and habit formation, and are dysregulated in disorders characterized by impaired action control. Therefore, a mechanistic investigation of the processes regulating corticostriatal transmission is key to understanding DLS-associated circuit function, behaviour and pathology. Presynaptic GABA(B) and group II metabotropic glutamate (mGlu2/3) receptors exert marked inhibitory control over corticostriatal glutamate release in the DLS, yet the signalling pathways through which they do so are unclear. We developed a novel approach using the genetically encoded calcium (Ca(2+) ) indicator GCaMP6 to assess presynaptic Ca(2+) in corticostriatal projections to the DLS. Using simultaneous photometric presynaptic Ca(2+) and striatal field potential recordings, we report that relative to P/Q-type Ca(2+) channels, N-type channels preferentially contributed to evoked presynaptic Ca(2+) influx in motor cortex projections to, and excitatory transmission in, the DLS. Activation of GABA(B) or mGlu2/3 receptors inhibited both evoked presynaptic Ca(2+) transients and striatal field potentials. mGlu2/3 receptor-mediated depression did not require functional N-type Ca(2+) channels, but was attenuated by blockade of P/Q-type channels. These findings reveal presynaptic mechanisms of inhibitory modulation of corticostriatal function that probably contribute to the selection and shaping of behavioural repertoires.
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Affiliation(s)
- David A Kupferschmidt
- Section on Synaptic Pharmacology & In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, US National Institutes of Health, Rockville, MD, USA
| | - David M Lovinger
- Section on Synaptic Pharmacology & In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, US National Institutes of Health, Rockville, MD, USA
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19
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Abstract
In this review, we explore the similarities and differences in the behavioural neurobiology found in the mouse models of Huntington's disease (HD) and the human disease state. The review is organised with a comparative focus on the functional domains of motor control, cognition and behavioural disturbance (akin to psychiatric disturbance in people) and how our knowledge of the underlying physiological changes that are manifest in the HD mouse lines correspond to those seen in the HD clinical population. The review is framed in terms of functional circuitry and neurotransmitter systems and how abnormalities in these systems impact on the behavioural readouts across the mouse lines and how these may correspond to the deficits observed in people. In addition, interpretational issues associated with the data from animal studies are discussed.
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Affiliation(s)
- Simon P Brooks
- Brain Repair Group, Division of Neuroscience, Cardiff University School of Bioscience, Museum Avenue, Cardiff, Wales, UK,
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20
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Motor, visual and emotional deficits in mice after closed-head mild traumatic brain injury are alleviated by the novel CB2 inverse agonist SMM-189. Int J Mol Sci 2014; 16:758-87. [PMID: 25561230 PMCID: PMC4307274 DOI: 10.3390/ijms16010758] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/22/2014] [Indexed: 11/17/2022] Open
Abstract
We have developed a focal blast model of closed-head mild traumatic brain injury (TBI) in mice. As true for individuals that have experienced mild TBI, mice subjected to 50-60 psi blast show motor, visual and emotional deficits, diffuse axonal injury and microglial activation, but no overt neuron loss. Because microglial activation can worsen brain damage after a concussive event and because microglia can be modulated by their cannabinoid type 2 receptors (CB2), we evaluated the effectiveness of the novel CB2 receptor inverse agonist SMM-189 in altering microglial activation and mitigating deficits after mild TBI. In vitro analysis indicated that SMM-189 converted human microglia from the pro-inflammatory M1 phenotype to the pro-healing M2 phenotype. Studies in mice showed that daily administration of SMM-189 for two weeks beginning shortly after blast greatly reduced the motor, visual, and emotional deficits otherwise evident after 50-60 psi blasts, and prevented brain injury that may contribute to these deficits. Our results suggest that treatment with the CB2 inverse agonist SMM-189 after a mild TBI event can reduce its adverse consequences by beneficially modulating microglial activation. These findings recommend further evaluation of CB2 inverse agonists as a novel therapeutic approach for treating mild TBI.
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21
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Deng YP, Wong T, Wan JY, Reiner A. Differential loss of thalamostriatal and corticostriatal input to striatal projection neuron types prior to overt motor symptoms in the Q140 knock-in mouse model of Huntington's disease. Front Syst Neurosci 2014; 8:198. [PMID: 25360089 PMCID: PMC4197654 DOI: 10.3389/fnsys.2014.00198] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 09/23/2014] [Indexed: 11/13/2022] Open
Abstract
Motor slowing and forebrain white matter loss have been reported in premanifest Huntington's disease (HD) prior to substantial striatal neuron loss. These findings raise the possibility that early motor defects in HD may be related to loss of excitatory input to striatum. In a prior study, we showed that in the heterozygous Q140 knock-in mouse model of HD that loss of thalamostriatal axospinous terminals is evident by 4 months, and loss of corticostriatal axospinous terminals is evident at 12 months, before striatal projection neuron pathology. In the present study, we specifically characterized the loss of thalamostriatal and corticostriatal terminals on direct (dSPN) and indirect (iSPN) pathway striatal projection neurons, using immunolabeling to identify thalamostriatal (VGLUT2+) and corticostriatal (VGLUT1+) axospinous terminals, and D1 receptor immunolabeling to distinguish dSPN (D1+) and iSPN (D1-) synaptic targets. We found that the loss of corticostriatal terminals at 12 months of age was preferential for D1+ spines, and especially involved smaller terminals, presumptively of the intratelencephalically projecting (IT) type. By contrast, indirect pathway D1- spines showed little loss of axospinous terminals at the same age. Thalamostriatal terminal loss was comparable for D1+ and D1- spines at both 4 and 12 months. Regression analysis showed that the loss of VGLUT1+ terminals on D1+ spines was correlated with a slight decline in open field motor parameters at 12 months. Our overall results raise the possibility that differential thalamic and cortical input loss to SPNs is an early event in human HD, with cortical loss to dSPNs in particular contributing to premanifest motor slowing.
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Affiliation(s)
- Yun-Ping Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Ting Wong
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Jim Y Wan
- Department of Preventive Medicine, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center Memphis, TN, USA
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22
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Sepers MD, Raymond LA. Mechanisms of synaptic dysfunction and excitotoxicity in Huntington's disease. Drug Discov Today 2014; 19:990-6. [DOI: 10.1016/j.drudis.2014.02.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 02/24/2014] [Indexed: 12/19/2022]
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23
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Dhanya RP, Sheffler DJ, Dahl R, Davis M, Lee PS, Yang L, Nickols HH, Cho HP, Smith LH, D'Souza MS, Conn PJ, Der-Avakian A, Markou A, Cosford NDP. Design and synthesis of systemically active metabotropic glutamate subtype-2 and -3 (mGlu2/3) receptor positive allosteric modulators (PAMs): pharmacological characterization and assessment in a rat model of cocaine dependence. J Med Chem 2014; 57:4154-72. [PMID: 24735492 PMCID: PMC4033659 DOI: 10.1021/jm5000563] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
![]()
As
part of our ongoing small-molecule metabotropic glutamate (mGlu) receptor
positive allosteric modulator (PAM) research, we performed structure–activity
relationship (SAR) studies around a series of group II mGlu PAMs.
Initial analogues exhibited weak activity as mGlu2 receptor
PAMs and no activity at mGlu3. Compound optimization led
to the identification of potent mGlu2/3 selective PAMs
with no in vitro activity at mGlu1,4–8 or 45 other
CNS receptors. In vitro pharmacological characterization of representative
compound 44 indicated agonist-PAM activity toward mGlu2 and PAM activity at mGlu3. The most potent mGlu2/3 PAMs were characterized in assays predictive of ADME/T
and pharmacokinetic (PK) properties, allowing the discovery of systemically
active mGlu2/3 PAMs. On the basis of its overall profile,
compound 74 was selected for behavioral studies and was
shown to dose-dependently decrease cocaine self-administration in
rats after intraperitoneal administration. These mGlu2/3 receptor PAMs have significant potential as small molecule tools
for investigating group II mGlu pharmacology.
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Affiliation(s)
- Raveendra-Panickar Dhanya
- Cell Death and Survival Networks Program and Conrad Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute , 10901 N. Torrey Pines Road, La Jolla, California 92037, United States
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Heldt SA, Elberger AJ, Deng Y, Guley NH, Del Mar N, Rogers J, Choi GW, Ferrell J, Rex TS, Honig MG, Reiner A. A novel closed-head model of mild traumatic brain injury caused by primary overpressure blast to the cranium produces sustained emotional deficits in mice. Front Neurol 2014; 5:2. [PMID: 24478749 PMCID: PMC3898331 DOI: 10.3389/fneur.2014.00002] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/06/2014] [Indexed: 12/14/2022] Open
Abstract
Emotional disorders are a common outcome from mild traumatic brain injury (TBI) in humans, but their pathophysiological basis is poorly understood. We have developed a mouse model of closed-head blast injury using an air pressure wave delivered to a small area on one side of the cranium, to create mild TBI. We found that 20-psi blasts in 3-month-old C57BL/6 male mice yielded no obvious behavioral or histological evidence of brain injury, while 25-40 psi blasts produced transient anxiety in an open field arena but little histological evidence of brain damage. By contrast, 50-60 psi blasts resulted in anxiety-like behavior in an open field arena that became more evident with time after blast. In additional behavioral tests conducted 2-8 weeks after blast, 50-60 psi mice also demonstrated increased acoustic startle, perseverance of learned fear, and enhanced contextual fear, as well as depression-like behavior and diminished prepulse inhibition. We found no evident cerebral pathology, but did observe scattered axonal degeneration in brain sections from 50 to 60 psi mice 3-8 weeks after blast. Thus, the TBI caused by single 50-60 psi blasts in mice exhibits the minimal neuronal loss coupled to "diffuse" axonal injury characteristic of human mild TBI. A reduction in the abundance of a subpopulation of excitatory projection neurons in basolateral amygdala enriched in Thy1 was, however, observed. The reported link of this neuronal population to fear suppression suggests their damage by mild TBI may contribute to the heightened anxiety and fearfulness observed after blast in our mice. Our overpressure air blast model of concussion in mice will enable further studies of the mechanisms underlying the diverse emotional deficits seen after mild TBI.
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Affiliation(s)
- Scott A. Heldt
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Andrea J. Elberger
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Yunping Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Natalie H. Guley
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Nobel Del Mar
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Joshua Rogers
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Gy Won Choi
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jessica Ferrell
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Tonia S. Rex
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Ophthalmology and Visual Sciences, Vanderbilt University, Nashville, TN, USA
| | - Marcia G. Honig
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN, USA
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis, TN, USA
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25
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Williams CJ, Dexter DT. Neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease. J Neurochem 2013; 129:4-20. [PMID: 24224472 DOI: 10.1111/jnc.12608] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 10/28/2013] [Accepted: 11/06/2013] [Indexed: 12/21/2022]
Abstract
Neurodegenerative disorders possess common pathological mechanisms, such as protein aggregation, inflammation, oxidative stress (OS) and excitotoxicity, raising the possibility of shared therapeutic targets. As a result of the selective cellular and regional expression of group III metabotropic glutamate (mGlu) receptors, drugs targeting such receptors have demonstrated both neuroprotective properties and symptomatic improvements in several models of neurodegeneration. In recent years, the discovery and development of subtype-selective ligands for the group III mGlu receptors has gained pace, allowing further research into the functions of these receptors and revealing their roles in health and disease. Activation of this class of receptors results in neuroprotection, with a variety of underlying mechanisms implicated. Group III mGlu receptor stimulation prevents excitotoxicity by inhibiting glutamate release from neurons and microglia and increasing glutamate uptake by astrocytes. It also attenuates the neuroinflammatory response by reducing glial reactivity and encourages neurotrophic phenotypes. This article will review the current literature with regard to the neuroprotective and symptomatic effects of group III mGlu receptor activation and discuss their promise as therapeutic targets in neurodegenerative disease. We review the neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease: Excess extracellular glutamate causes overactivation of NMDA receptors resulting in excitotoxicity. Externalization of phosphatidylserine stimulates phagocytosis of neurons by activated microglia, which contribute to damage through glutamate and pro-inflammatory factor release. Reactive astrocytes produce cytotoxic factors enhancing neuronal cell death. Activation of group III mGlu receptors by glutamate and/or mGlu receptor ligands results in inhibition of glutamate release from presynaptic terminals and microglia, reducing excitotoxicity. Astrocytic glutamate uptake is increased and microglia produce neurotrophic factors.
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Affiliation(s)
- Claire J Williams
- Parkinson's Disease Research Group, Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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26
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Heng BC, Aubel D, Fussenegger M. An overview of the diverse roles of G-protein coupled receptors (GPCRs) in the pathophysiology of various human diseases. Biotechnol Adv 2013; 31:1676-94. [DOI: 10.1016/j.biotechadv.2013.08.017] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 12/23/2022]
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27
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Effects of group II and III metabotropic glutamate receptor ligands on conditioned taste aversion learning. Behav Brain Res 2013; 253:9-16. [DOI: 10.1016/j.bbr.2013.06.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 06/22/2013] [Accepted: 06/27/2013] [Indexed: 12/13/2022]
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28
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Loss of corticostriatal and thalamostriatal synaptic terminals precedes striatal projection neuron pathology in heterozygous Q140 Huntington's disease mice. Neurobiol Dis 2013; 60:89-107. [PMID: 23969239 DOI: 10.1016/j.nbd.2013.08.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/22/2013] [Accepted: 08/07/2013] [Indexed: 01/18/2023] Open
Abstract
Motor slowing, forebrain white matter loss, and striatal shrinkage have been reported in premanifest Huntington's disease (HD) prior to overt striatal neuron loss. We carried out detailed LM and EM studies in a genetically precise HD mimic, heterozygous Q140 HD knock-in mice, to examine the possibility that loss of corticostriatal and thalamostriatal terminals prior to striatal neuron loss underlies these premanifest HD abnormalities. In our studies, we used VGLUT1 and VGLUT2 immunolabeling to detect corticostriatal and thalamostriatal (respectively) terminals in dorsolateral (motor) striatum over the first year of life, prior to striatal projection neuron pathology. VGLUT1+ axospinous corticostriatal terminals represented about 55% of all excitatory terminals in striatum, and VGLUT2+ axospinous thalamostriatal terminals represented about 35%, with VGLUT1+ and VGLUT2+ axodendritic terminals accounting for the remainder. In Q140 mice, a significant 40% shortfall in VGLUT2+ axodendritic thalamostriatal terminals and a 20% shortfall in axospinous thalamostriatal terminals were already observed at 1 month of age, but VGLUT1+ terminals were normal in abundance. The 20% deficiency in VGLUT2+ thalamostriatal axospinous terminals persisted at 4 and 12 months in Q140 mice, and an additional 30% loss of VGLUT1+ corticostriatal terminals was observed at 12 months. The early and persistent deficiency in thalamostriatal axospinous terminals in Q140 mice may reflect a development defect, and the impoverishment of this excitatory drive to striatum may help explain early motor defects in Q140 mice and in premanifest HD. The loss of corticostriatal terminals at 1 year in Q140 mice is consistent with prior evidence from other mouse models of corticostriatal disconnection early during progression, and can explain both the measurable bradykinesia and striatal white matter loss in late premanifest HD.
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29
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Monn JA, Valli MJ, Massey SM, Hao J, Reinhard MR, Bures MG, Heinz BA, Wang X, Carter JH, Getman BG, Stephenson GA, Herin M, Catlow JT, Swanson S, Johnson BG, McKinzie DL, Henry SS. Synthesis and Pharmacological Characterization of 4-Substituted-2-Aminobicyclo[3.1.0]hexane-2,6-dicarboxylates: Identification of New Potent and Selective Metabotropic Glutamate 2/3 Receptor Agonists. J Med Chem 2013; 56:4442-55. [DOI: 10.1021/jm4000165] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James A. Monn
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Matthew J. Valli
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Steven M. Massey
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Junliang Hao
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Matthew R. Reinhard
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Mark G. Bures
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Beverly A. Heinz
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Xushan Wang
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Joan H. Carter
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Brian G. Getman
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Gregory A. Stephenson
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Marc Herin
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - John T. Catlow
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Steven Swanson
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Bryan G. Johnson
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - David L. McKinzie
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
| | - Steven S. Henry
- Discovery
Chemistry Research and Technologies, §Preformulation, ∥Drug Disposition and ⊥Neuroscience Research, Eli Lilly and Company, Indianapolis,
Indiana 46285, United States
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Mrzljak L, Munoz-Sanjuan I. Therapeutic Strategies for Huntington's Disease. Curr Top Behav Neurosci 2013; 22:161-201. [PMID: 24277342 DOI: 10.1007/7854_2013_250] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Huntington's disease (HD) is a devastating autosomal dominant neurodegenerative disease, caused by expansion of the CAG repeat in the huntingtin (HTT) gene and characterized pathologically by the loss of pyramidal neurons in several cortical areas, of striatal medium spiny neurons, and of hypothalamic neurons. Clinically, a distinguishing feature of the disease is uncontrolled involuntary movements (chorea, dyskensias) accompanied by progressive cognitive, motor, and psychiatric impairment. This review focuses on the current state of therapeutic development for the treatment of HD, including the preclinical and clinical development of small molecules and molecular therapies.
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Tang W, Su D. Locomotion analysis and its applications in neurological disorders detection: state-of-art review. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s13721-012-0020-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Switonski PM, Szlachcic WJ, Gabka A, Krzyzosiak WJ, Figiel M. Mouse models of polyglutamine diseases in therapeutic approaches: review and data table. Part II. Mol Neurobiol 2012; 46:430-66. [PMID: 22944909 PMCID: PMC3461214 DOI: 10.1007/s12035-012-8316-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 07/29/2012] [Indexed: 12/13/2022]
Abstract
Mouse models of human diseases are created both to understand the pathogenesis of the disorders and to find successful therapies for them. This work is the second part in a series of reviews of mouse models of polyglutamine (polyQ) hereditary disorders and focuses on in vivo experimental therapeutic approaches. Like part I of the polyQ mouse model review, this work is supplemented with a table that contains data from experimental studies of therapeutic approaches in polyQ mouse models. The aim of this review was to characterize the benefits and outcomes of various therapeutic strategies in mouse models. We examine whether the therapeutic strategies are specific to a single disease or are applicable to more than one polyQ disorder in mouse models. In addition, we discuss the suitability of mouse models in therapeutic approaches. Although the majority of therapeutic studies were performed in mouse models of Huntington disease, similar strategies were also used in other disease models.
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Affiliation(s)
- Pawel M Switonski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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Reiner A, Wang HB, Del Mar N, Sakata K, Yoo W, Deng YP. BDNF may play a differential role in the protective effect of the mGluR2/3 agonist LY379268 on striatal projection neurons in R6/2 Huntington's disease mice. Brain Res 2012; 1473:161-72. [PMID: 22820300 DOI: 10.1016/j.brainres.2012.07.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 07/04/2012] [Accepted: 07/12/2012] [Indexed: 10/28/2022]
Abstract
We have found that daily subcutaneous injection with a maximum tolerated dose (MTD) of the mGluR2/3 agonist LY379268 (20mg/kg) beginning at 4 weeks dramatically improves the phenotype in R6/2 mice. For example, we observed normalization of motor function in distance traveled, speed, the infrequency of pauses, and the ability to locomote in a straight line, and a rescue of a 15-20% striatal neuron loss at 10 weeks. As acute LY379268 treatment is known to increase cortical BDNF production, and BDNF is known to be beneficial for striatal neurons, we investigated if the benefit of daily LY379268 in R6/2 mice for striatal projection neurons was associated with increases in corticostriatal BDNF, with assessments done at 10 weeks of age after daily MTD treatment since the fourth week of life. We found that LY379268 increased BDNF expression in layer 5 neurons in motor cortex, which project to striatum, partly rescued a preferential loss of enkephalinergic striatal neurons, and enhanced substance P (SP) expression by SP striatal projection neurons. The enhanced survival of enkephalinergic striatal neurons was correlated with the cortical BDNF increase, but the enhanced SP expression by SP striatal neurons was not. Thus, LY379268 may protect the two main striatal projection neuron types by different mechanisms, enkephalinergic neurons by the trophic benefit of BDNF, and SP neurons by a mechanism not involving BDNF. The SP neuron benefit may perhaps instead involve the anti-excitotoxic action of mGluR2/3 receptor agonists.
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Affiliation(s)
- A Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, 855 Monroe Ave, Memphis, TN 38163, USA.
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