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Bellum S, Bawa B, Thuett KA, Stoica G, Abbott LC. Changes in Biochemical Processes in Cerebellar Granule Cells of Mice Exposed To Methylmercury. Int J Toxicol 2017; 26:261-9. [PMID: 17564908 DOI: 10.1080/10915810701369758] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
At postnatal day 34, male and female C57BL/6J mice were exposed orally once a day to a total of five doses totaling 1.0 or 5.0 mg/kg of methylmercuric chloride or sterile deionized water in moistened rodent chow. Eleven days after the last dose cerebellar granule cells were acutely isolated to measure reactive oxygen species (ROS) levels and mitochondrial membrane potential using CM-H2DCFDA and TMRM dyes, respectively. For visualizing intracellular calcium ion distribution using transmission electron microscopy, mice were perfused 11 days after the last dose of methylmercury (MeHg) using the oxalate-pyroantimonate method. Cytosolic and mitochondrial protein fractions from acutely isolated granule cells were analyzed for cytochrome c content using Western blot analysis. Histochemistry (Fluoro-Jade dye) and immunohistochemistry (activated caspase 3) was performed on frozen serial cerebellar sections to label granule cell death and activation of caspase 3, respectively. Granule cells isolated from MeHg-treated mice showed elevated ROS levels and decreased mitochondrial membrane potential when compared to granule cells from control mice. Electron photomicrographs of MeHg-treated granule cells showed altered intracellular calcium ion homeostasis ([Ca2+]i) when compared to control granule cells. However, in spite of these subcellular changes and moderate relocalization of cytochrome c into the cytosol, the concentrations of MeHg used in this study did not produce significant neuronal cell death/apoptosis at the time point examined, as evidenced by Fluoro-Jade and activated caspase 3 immunostaining, respectively. These results demonstrate that short-term in vivo exposure to total doses of 1.0 and 5.0 mg/kg MeHg through the most common exposure route (oral) can result in significant subcellular changes that are not accompanied by overt neuronal cell death.
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Affiliation(s)
- Sairam Bellum
- Department of Safety Assessment, Merck Research Laboratories, West Point, Pennsylvania, USA
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Neural cell proliferation and survival in the hippocampus of adult CaV 2.1 calcium ion channel mutant mice. Brain Res 2016; 1650:162-171. [DOI: 10.1016/j.brainres.2016.08.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 07/29/2016] [Accepted: 08/26/2016] [Indexed: 02/06/2023]
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Scholl EA, Dudek FE, Ekstrand JJ. Neuronal degeneration is observed in multiple regions outside the hippocampus after lithium pilocarpine-induced status epilepticus in the immature rat. Neuroscience 2013; 252:45-59. [PMID: 23896573 DOI: 10.1016/j.neuroscience.2013.07.045] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 01/25/2023]
Abstract
Although hippocampal sclerosis is frequently identified as a possible epileptic focus in patients with temporal lobe epilepsy, neuronal loss has also been observed in additional structures, including areas outside the temporal lobe. The claim from several researchers using animal models of acquired epilepsy that the immature brain can develop epilepsy without evidence of hippocampal neuronal death raises the possibility that neuronal death in some of these other regions may also be important for epileptogenesis. The present study used the lithium pilocarpine model of acquired epilepsy in immature animals to assess which structures outside the hippocampus are injured acutely after status epilepticus. Sprague-Dawley rat pups were implanted with surface EEG electrodes, and status epilepticus was induced at 20 days of age with lithium pilocarpine. After 72 h, brain tissue from 12 animals was examined with Fluoro-Jade B, a histochemical marker for degenerating neurons. All animals that had confirmed status epilepticus demonstrated Fluoro-Jade B staining in areas outside the hippocampus. The most prominent staining was seen in the thalamus (mediodorsal, paratenial, reuniens, and ventral lateral geniculate nuclei), amygdala (ventral lateral, posteromedial, and basomedial nuclei), ventral premammillary nuclei of hypothalamus, and paralimbic cortices (perirhinal, entorhinal, and piriform) as well as parasubiculum and dorsal endopiriform nuclei. These results demonstrate that lithium pilocarpine-induced status epilepticus in the immature rat brain consistently results in neuronal injury in several distinct areas outside of the hippocampus. Many of these regions are similar to areas damaged in patients with temporal lobe epilepsy, thus suggesting a possible role in epileptogenesis.
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Key Words
- AA
- ACH
- ACo
- AD
- AHC
- AI
- AM
- AO
- APir
- AStr
- AV
- Acb
- AcbSh
- BAOT
- BLA
- BLP
- BLV
- BMA
- BMP
- BSTIA
- BSTM
- CA
- CL
- CM
- CPu
- CeL
- CeM
- Cg1-3
- DEn
- DG
- DI
- DLG
- DP
- EEG
- Ent
- Fluoro-jade B
- Fr1-3
- GABA
- GI
- GP
- HC
- Hil
- I
- IL
- LDDM
- LDVL
- LHb
- LM
- LO
- LOT
- LPLR
- LPMR
- LSD
- LSI
- LSV
- LaD
- LaV
- MD
- MGD
- MGM
- MGP
- MGV
- MHb
- MO
- MS
- MTu
- MeA
- MePD
- MePV
- NAc
- Oc2L
- P
- PC
- PF
- PLCo
- PMCo
- PMD
- PMV
- PRh
- PT
- PVA
- PVP
- PaS
- Par1
- Pir
- Po
- PrS
- RSA
- RSG
- Re
- Rh
- Rt
- S
- SG
- SI
- SNR
- STh
- TLE
- Te1,3
- VL
- VLG
- VLO
- VM
- VP
- VPL
- VPM
- VTR
- ZI
- accumbens
- accumbens shell
- agranular insular cortex
- amygdalopiriform transition area
- amygdalostriatal transition area
- anterior amygdaloid area
- anterior cingulate
- anterior cortical nucleus
- anterior hypothalamic area
- anterior hypothalamic area, central
- anterior olfactory nucleus
- anterodorsal nucleus
- anteromedial
- anteroventral nucleus
- basolateral nucleus, anterior
- basolateral nucleus, posterior
- basolateral nucleus, ventral
- basomedial nucleus, anterior
- basomedial nucleus, posterior
- bed nucleus accessory olfactory tract
- bed nucleus stria terminalis, intraamygdaloid division
- bed stria terminalis nuclei
- caudate putamen
- central nucleus, lateral
- central nucleus, medial
- centrolateral nucleus
- centromedial nucleus
- cornu ammonis
- dentate gyrus
- dorsal endopiriform nucleus
- dorsal peduncular
- dorsolateral geniculate nucleus
- dysgranular insular cortex
- electroencephalogram
- entorhinal cortex
- frontal cortex
- globus pallidus
- granular insular cortex
- hilus
- hippocampus
- immature brain
- infralimbic
- intercalated masses
- lateral habenula
- lateral mammillary
- lateral nucleus, dorsal
- lateral nucleus, ventral
- lateral orbital cortex
- lateral septal, dorsal
- lateral septal, intermediate
- lateral septal, ventral
- laterodorsal nucleus, dorsomedial
- laterodorsal nucleus, ventrolateral
- lateroposterior nucleus, lateral rostral
- lateroposterior nucleus, medial rostral
- lithium pilocarpine
- medial geniculate nucleus, dorsal
- medial geniculate nucleus, medial
- medial geniculate nucleus, ventral
- medial globus pallidus
- medial habenula
- medial nucleus, anterior
- medial nucleus, posterodorsal
- medial nucleus, posteroventral
- medial orbital cortex
- medial septal
- medial tuberal
- mediodorsal nucleus
- nucleus accumbens
- nucleus lateral olfactory tract
- occipital cortex
- paracentral
- parafasicular
- parasubiculum
- paratenial
- paraventricular nucleus, anterior
- paraventricular nucleus, posterior
- parietal cortex
- perirhinal cortex
- piriform cortex
- post-natal day
- posterior nucleus
- posterolateral cortical nucleus
- posteromedial cortical nucleus
- premammillary nucleus, dorsal
- premammillary nucleus, ventral
- presubiculum
- reticular nucleus
- retrosplenial agranular cortex
- retrosplenial granular cortex
- reuniens nucleus
- rhomboid nucleus
- status epilepticus
- subiculum
- substantia innominate
- substantia nigra pars reticulate
- subthalamic nucleus
- suprageniculate nucleus
- temporal cortex
- temporal lobe epilepsy
- vRe
- ventral pallidum
- ventral posterolateral nucleus
- ventral posteromedial nucleus
- ventral reuniens nucleus
- ventral tegmental area
- ventrolateral geniculate nucleus
- ventrolateral nucleus
- ventrolateral orbital cortex
- ventromedial nucleus
- zona incerta
- γ-aminobutyric acid
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Affiliation(s)
- E A Scholl
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States
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Nguyen TA, Frank-Cannon T, Martinez TN, Ruhn KA, Marvin M, Casey B, Treviño I, Hong JJ, Goldberg MS, Tansey MG. Analysis of inflammation-related nigral degeneration and locomotor function in DJ-1(-/-) mice. J Neuroinflammation 2013; 10:50. [PMID: 23622116 PMCID: PMC3769147 DOI: 10.1186/1742-2094-10-50] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 03/26/2013] [Indexed: 11/26/2022] Open
Abstract
Background Complex interactions involving genetic susceptibility and environmental factors are thought to underlie the pathogenesis of Parkinson’s disease (PD). Although the role of inflammatory processes in modulating risk for development of PD has yet to be fully understood, prospective studies suggest that chronic use of NSAIDs reduce the incidence of PD. Loss-of-function mutations in the DJ-1 gene cause a rare form of familial PD with an autosomal recessive pattern of inheritance; however, DJ-1−/− mice do not display nigrostriatal pathway degeneration, suggesting that additional factors such as inflammation may be needed to induce neurodegeneration on the background of DJ-1 gene mutations. Neuroinflammation causes oxidative stress and, based on evidence that DJ-1 plays a protective role against oxidative stress, we investigated whether DJ-1−/− mice display increased vulnerability to inflammation-induced nigral degeneration. Methods We exposed adult wild-type and DJ-1−/− mice to repeated intranasal administration of soluble TNF (inTNF) or repeated intraperitoneal injections of low-dose lipopolysaccharide (LPS) or saline vehicle. We measured locomotor performance using a variety of behavior tasks, striatal dopamine (DA) content by HPLC, DA neuron (TH+ cells) and total neuron (NeuN+ cells) number in the substantia nigra pars compacta and ventral tegmental area by unbiased stereology, number of Iba1-positive microglia, and mRNA levels of inflammatory and oxidative stress genes by quantitative PCR in the midbrain, cortex and isolated peritoneal macrophages of DJ-1−/− and wild-type mice. Results We found that chronic LPS injections induced similar neuroinflammatory responses in the midbrains of DJ-1−/− mice and wild-type mice and neither group developed locomotor deficits or nigral degeneration. inTNF administration did not appear to induce neuroinflammatory responses in LPS-treated wild-type or DJ-1−/− mice. The lack of vulnerability to inflammation-induced nigral degeneration was not due to enhanced anti-oxidant gene responses in the midbrains of DJ-1−/− mice which, in fact, displayed a blunted response relative to that of wild-type mice. Peripheral macrophages from wild-type and DJ-1−/− mice displayed similar basal and LPS-induced inflammatory and oxidative stress markers in vitro. Conclusions Our studies indicate that DJ-1−/− mice do not display increased vulnerability to inflammation-related nigral degeneration in contrast to what has been reported for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrindine. We conclude that either DJ-1 does not have a critical role in protecting DA neurons against inflammation-induced oxidative stress and/or there is compensatory gene expression in the midbrain of DJ-1−/− mice that renders them resistant to the cytotoxic effects triggered by chronic peripheral inflammation.
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Affiliation(s)
- Thi A Nguyen
- Department of Physiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390, USA
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Fitzgerald DP, Subramanian P, Deshpande M, Graves C, Gordon I, Qian Y, Snitkovsky Y, Liewehr DJ, Steinberg SM, Paltán-Ortiz JD, Herman MM, Camphausen K, Palmieri D, Becerra SP, Steeg PS. Opposing effects of pigment epithelium-derived factor on breast cancer cell versus neuronal survival: implication for brain metastasis and metastasis-induced brain damage. Cancer Res 2012; 72:144-53. [PMID: 22215693 DOI: 10.1158/0008-5472.can-11-1904] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Brain metastases are a significant cause of morbidity and mortality for patients with cancer, yet preventative and therapeutic options remain an unmet need. The cytokine pigment epithelium-derived factor (PEDF) is downregulated in resected human brain metastases of breast cancer compared with primary breast tumors, suggesting that restoring its expression might limit metastatic spread. Here, we show that outgrowth of large experimental brain metastases from human 231-BR or murine 4T1-BR breast cancer cells was suppressed by PEDF expression, as supported by in vitro analyses as well as direct intracranial implantation. Notably, the suppressive effects of PEDF were not only rapid but independent of the effects of this factor on angiogenesis. Paralleling its cytotoxic effects on breast cancer cells, PEDF also exerted a prosurvival effect on neurons that shielded the brain from tumor-induced damage, as indicated by a relative 3.5-fold reduction in the number of dying neurons adjacent to tumors expressing PEDF. Our findings establish PEDF as both a metastatic suppressor and a neuroprotectant in the brain, highlighting its role as a double agent in limiting brain metastasis and its local consequences.
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Affiliation(s)
- Daniel P Fitzgerald
- Women's Cancer's Section, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institute of Mental Health, Bethesda, Maryland 20892, USA
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6
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Oliver PL, Finelli MJ, Edwards B, Bitoun E, Butts DL, Becker EBE, Cheeseman MT, Davies B, Davies KE. Oxr1 is essential for protection against oxidative stress-induced neurodegeneration. PLoS Genet 2011; 7:e1002338. [PMID: 22028674 PMCID: PMC3197693 DOI: 10.1371/journal.pgen.1002338] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 08/24/2011] [Indexed: 01/19/2023] Open
Abstract
Oxidative stress is a common etiological feature of neurological disorders, although the pathways that govern defence against reactive oxygen species (ROS) in neurodegeneration remain unclear. We have identified the role of oxidation resistance 1 (Oxr1) as a vital protein that controls the sensitivity of neuronal cells to oxidative stress; mice lacking Oxr1 display cerebellar neurodegeneration, and neurons are less susceptible to exogenous stress when the gene is over-expressed. A conserved short isoform of Oxr1 is also sufficient to confer this neuroprotective property both in vitro and in vivo. In addition, biochemical assays indicate that Oxr1 itself is susceptible to cysteine-mediated oxidation. Finally we show up-regulation of Oxr1 in both human and pre-symptomatic mouse models of amyotrophic lateral sclerosis, indicating that Oxr1 is potentially a novel neuroprotective factor in neurodegenerative disease.
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Affiliation(s)
- Peter L. Oliver
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Mattéa J. Finelli
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Benjamin Edwards
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Emmanuelle Bitoun
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Darcy L. Butts
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | - Esther B. E. Becker
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Ben Davies
- Wellcome Trust Centre for Human Genetics, Oxford, United Kingdom
| | - Kay E. Davies
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, United Kingdom
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7
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Druga R, Mareš P, Kubová H. Time course of neuronal damage in the hippocampus following lithium-pilocarpine status epilepticus in 12-day-old rats. Brain Res 2010; 1355:174-9. [DOI: 10.1016/j.brainres.2010.07.072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Revised: 07/20/2010] [Accepted: 07/20/2010] [Indexed: 10/19/2022]
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8
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McAlpine FE, Lee JK, Harms AS, Ruhn KA, Blurton-Jones M, Hong J, Das P, Golde TE, LaFerla FM, Oddo S, Blesch A, Tansey MG. Inhibition of soluble TNF signaling in a mouse model of Alzheimer's disease prevents pre-plaque amyloid-associated neuropathology. Neurobiol Dis 2009; 34:163-77. [PMID: 19320056 DOI: 10.1016/j.nbd.2009.01.006] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Microglial activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in Alzheimer's disease (AD). Elevated levels of the pro-inflammatory cytokine tumor necrosis factor (TNF) have been reported in serum and post-mortem brains of patients with AD, but its role in progression of AD is unclear. Using novel engineered dominant negative TNF inhibitors (DN-TNFs) selective for soluble TNF (solTNF), we investigated whether blocking TNF signaling with chronic infusion of the recombinant DN-TNF XENP345 or a single injection of a lentivirus encoding DN-TNF prevented the acceleration of AD-like pathology induced by chronic systemic inflammation in 3xTgAD mice. We found that chronic inhibition of solTNF signaling with either approach decreased the LPS-induced accumulation of 6E10-immunoreactive protein in hippocampus, cortex, and amygdala. Immunohistological and biochemical approaches using a C-terminal APP antibody indicated that a major fraction of the accumulated protein was likely to be C-terminal APP fragments (beta-CTF) while a minor fraction consisted of Av40 and 42. Genetic inactivation of TNFR1-mediated TNF signaling in 3xTgAD mice yielded similar results. Taken together, our studies indicate that soluble TNF is a critical mediator of the effects of neuroinflammation on early (pre-plaque) pathology in 3xTgAD mice. Targeted inhibition of solTNF in the CNS may slow the appearance of amyloid-associated pathology, cognitive deficits, and potentially the progressive loss of neurons in AD.
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Affiliation(s)
- Fiona E McAlpine
- Department of Physiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9040, USA
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9
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Abstract
The loss of nigral dopaminergic (DA) neurons in idiopathic Parkinson's disease (PD) is believed to result from interactions between genetic susceptibility and environmental factors. Evidence that inflammatory processes modulate PD risk comes from prospective studies that suggest that higher plasma concentrations of a number of proinflammatory cytokines correlate with an increased risk of developing PD and chronic nonsteroidal anti-inflammatory drug regimens reduce the incidence of PD. Although loss-of-function mutations in the parkin gene cause early-onset familial PD, Parkin-deficient (parkin-/-) mice do not display nigrostriatal pathway degeneration, suggesting that a genetic factor is not sufficient, and an environmental trigger may be needed to cause nigral DA neuron loss. To test the hypothesis that parkin-/- mice require an inflammatory stimulus to develop nigral DA neuron loss, low-dose lipopolysaccaride (LPS) was administered intraperitoneally for prolonged periods. Quantitative real-time PCR and immunofluorescence labeling of inflammatory markers indicated that this systemic LPS treatment regimen triggered persistent neuroinflammation in wild-type and parkin-/- mice. Although inflammatory and oxidative stress responses to the inflammation regimen did not differ significantly between the two genotypes, only parkin-/- mice displayed subtle fine-motor deficits and selective loss of DA neurons in substantia nigra. Therefore, our studies suggest that loss of Parkin function increases the vulnerability of nigral DA neurons to inflammation-related degeneration. This new model of nigral DA neuron loss may enable identification of early biomarkers of degeneration and aid in preclinical screening efforts to identify compounds that can halt or delay the progressive degeneration of the nigrostriatal pathway.
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10
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Chidlow G, Wood JPM, Sarvestani G, Manavis J, Casson RJ. Evaluation of Fluoro-Jade C as a marker of degenerating neurons in the rat retina and optic nerve. Exp Eye Res 2008; 88:426-37. [PMID: 19010324 DOI: 10.1016/j.exer.2008.10.015] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Revised: 09/29/2008] [Accepted: 10/16/2008] [Indexed: 01/03/2023]
Abstract
Detection of neuronal death is an essential requirement for researchers investigating retinal degeneration. Fluoro-Jade C (FJC) is a novel, fluorescent dye that has been successfully used to label degenerating neurons in the brain, but its effectiveness in the eye has not been ascertained. In the current study, we determined the efficacy of FJC for detection of neuronal degeneration in the retina and optic nerve in various paradigms of injury. N-methyl-D-aspartate (NMDA) and kainic acid-induced excitotoxicity, optic nerve transection, and bilateral occlusion of the common carotid arteries (BCCAO) were performed using standard techniques. Rats were killed at various time points and the retinas with optic nerves attached were removed for tissue processing prior to labelling for FJC, for DNA fragmentation by TUNEL or for immunohistochemical analysis. Retinas from RCS rats of different ages were also analysed. After excitotoxicity-induced injury, cell bodies and dendrites within the ganglion cell and inner plexiform layers were specifically labelled by FJC within 6h, a time point comparable to the appearance of TUNEL-positive nuclei and to reductions in mRNA levels of retinal ganglion cell-specific proteins, but in advance of alterations in some immunohistochemical markers. The number of FJC-labelled cell bodies in the retina declined over time as cell loss proceeded, although dendritic staining remained prominent. Colocalisation of FJC with TUNEL and with immunohistochemical neuronal markers was achieved. FJC was successful at identifying somato-dendritic degeneration following ischemia induced by BCCAO, but surprisingly, not after optic nerve transection. FJC visualised photoreceptor degeneration in the RCS rat, albeit less effectively than with the TUNEL assay, and was also effective for imaging and quantifying degenerating axons in the optic nerve after multiple injuries. In addition to labelling degenerating neurons, however, FJC also bound non-specifically to astrocytes and to blood cells in unperfused rats. Since the ganglion cell layer is adjacent to astrocytes within the nerve fibre layer, caution is needed when using FJC as a quantitative tool for detecting ganglion cell death.
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Affiliation(s)
- Glyn Chidlow
- Ophthalmic Research Laboratories, South Australian Institute of Ophthalmology, Hanson Institute Centre for Neurological Diseases, Adelaide, SA, Australia
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11
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Bawa B, Abbott LC. Analysis of calcium ion homeostasis and mitochondrial function in cerebellar granule cells of adult CaV 2.1 calcium ion channel mutant mice. Neurotox Res 2008; 13:1-18. [PMID: 18367436 DOI: 10.1007/bf03033363] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
CaV 2.1 voltage-gated calcium channels (VGCC) are highly expressed by cerebellar neurons, and their dysfunction is linked to human disorders including familial hemiplegic migraine, episodic ataxia type 2 and spinocerebellar ataxia type 6. Altered calcium homeostasis, due to dysfunctional Ca(V 2.1 VGCC can severely affect mitochondrial function, eventually leading to neuronal cell death. We study leaner and tottering mice, which carry autosomal recessive mutations in the gene coding for the alpha 1A pore-forming subunit of CaV 2.1 VGCC. Both leaner and tottering mice exhibit cerebellar ataxia and epilepsy. Excessive leaner cerebellar granule cell (CGC) death starts soon after postnatal day 10, but it is not known whether the degree of CGC cell death observed in adult leaner mice is significantly different from wild type mice. We used Fluoro-Jade and TUNEL staining to quantify apoptotic cell death in leaner and wild type CGC. We investigated calcium homeostasis, mitochondrial function and generation of reactive oxygen species (ROS) in isolated CGC, using indicator dyes Fura-2AM, TMRM and CMH2DCFDA, respectively. We observed a small but significant increase in number of apoptotic adult leaner CGC. Calcium homeostasis and mitochondrial function also were altered in leaner CGC. However, no significant differences in ROS levels were observed. It is possible that CGC death in leaner mice may be related to mitochondrial dysfunction but may not be directly related to decreased basal intracellular calcium.
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Affiliation(s)
- Bhupinder Bawa
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biosciences, Texas A&M University, College Station, TX 77843-4458, USA
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12
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Repa JJ, Li H, Frank-Cannon TC, Valasek MA, Turley SD, Tansey MG, Dietschy JM. Liver X receptor activation enhances cholesterol loss from the brain, decreases neuroinflammation, and increases survival of the NPC1 mouse. J Neurosci 2007; 27:14470-80. [PMID: 18160655 PMCID: PMC6673433 DOI: 10.1523/jneurosci.4823-07.2007] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 11/16/2007] [Accepted: 11/16/2007] [Indexed: 11/21/2022] Open
Abstract
Although cholesterol is a major component of the CNS, there is little information on how or whether a change in sterol flux across the blood-brain barrier might alter neurodegeneration. In Niemann-Pick type C (NPC) disease, a mutation in NPC1 protein causes unesterified cholesterol to accumulate in the lysosomal compartment of every cell, including neurons and glia. Using the murine model of this disease, we used genetic and pharmacologic approaches in an attempt to alter cholesterol homeostasis across the CNS. Genetic deletion of the sterol transporters ATP-binding cassette transporter A1 (ABCA1) and low-density lipoprotein receptor in the NPC1 mouse did not affect sterol balance or longevity. However, deletion of the nuclear receptor, liver X receptor beta (LXRbeta), had an adverse effect on progression of the disease. We therefore tested the effects of increasing LXR activity by oral administration of a synthetic ligand for this transcription factor. Treatment with this LXR agonist increased cholesterol excretion out of brain from 17 to 49 microg per day, slowed neurodegeneration, and prolonged life. This agonist did not alter synthesis of cholesterol or expression of genes associated with the formation of 24(S)-hydroxycholesterol or neurosteroids such as CYP46A1, 3alphaHSD, and CYP11A1. However, levels of the sterol transporters ABCA1 and ATP-binding cassette transporter G1 were increased. Concomitantly, markers of neuroinflammation, CD14, MAC1, CD11c, and inducible nitric oxide synthase, were reduced, and microglia reverted from their amoeboid, active form to a ramified, resting configuration. Thus, LXR activation resulted in increased cholesterol excretion from the brain, decreased neuroinflammation, and deactivation of microglia to slow neurodegeneration and extend the lifespan of the NPC1 mouse.
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Affiliation(s)
- Joyce J. Repa
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, Texas 75390-9151, and
- Department of Physiology, University of Texas Southwestern Medical School, Dallas, Texas 75390-9077
| | - Hao Li
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, Texas 75390-9151, and
| | - Tamy C. Frank-Cannon
- Department of Physiology, University of Texas Southwestern Medical School, Dallas, Texas 75390-9077
| | - Mark A. Valasek
- Department of Physiology, University of Texas Southwestern Medical School, Dallas, Texas 75390-9077
| | - Stephen D. Turley
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, Texas 75390-9151, and
| | - Malú G. Tansey
- Department of Physiology, University of Texas Southwestern Medical School, Dallas, Texas 75390-9077
| | - John M. Dietschy
- Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas, Texas 75390-9151, and
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Alonso I, Marques JM, Sousa N, Sequeiros J, Olsson IAS, Silveira I. Motor and cognitive deficits in the heterozygous leaner mouse, a Cav2.1 voltage-gated Ca2+ channel mutant. Neurobiol Aging 2007; 29:1733-43. [PMID: 17513018 DOI: 10.1016/j.neurobiolaging.2007.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 03/26/2007] [Accepted: 04/05/2007] [Indexed: 11/28/2022]
Abstract
The leaner mutation in mice affects the Ca(v)2.1 voltage-gated calcium channel alpha(1A)-subunit gene (Cacna1a), causing a reduction in calcium currents predominantly in Purkinje cells. This reduction in calcium currents causes severe progressive cerebellar ataxia, beginning around postnatal day 10, in homozygous leaner mice (tg(la)/tg(la)), while their heterozygous littermates (tg(la)/+) present no obvious behavioral deficits. In humans, heterozygous mutations in the Cacna1a orthologous gene produce a broad range of neurological manifestations. To evaluate the phenotypic status of the tg(la)/+ animals, we assessed motor performance and cognition, at different ages, in these mutant mice. We were able to observe age-dependent impairment in motor and cognitive tasks; balance and motor learning deficits were found in demanding tasks on the rotarod and on the hanging wire test, while spatial learning and memory impairment was observed in the Morris water maze. Progressive dysfunction in escape reflexes, indicative of neurological impairment, was also present in tg(la)/+ animals. Although not presenting major motor alterations, tg(la)/+ mice show age-dependent motor and cognitive deficits.
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Affiliation(s)
- Isabel Alonso
- UnIGENe, IBMC, Universidade do Porto, Portugal; ICBAS, Universidade do Porto, Portugal
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14
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Bäurle J, Kranda K, Frischmuth S. On the variety of cell death pathways in the Lurcher mutant mouse. Acta Neuropathol 2006; 112:691-702. [PMID: 16969677 DOI: 10.1007/s00401-006-0137-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 08/22/2006] [Accepted: 08/22/2006] [Indexed: 12/19/2022]
Abstract
Apoptosis as well as autophagy have been implicated in the death of cerebellar Purkinje cells (PCs) in the Lurcher (Lc/+) mutant mouse and at least two different apoptotic pathways participate in the transsynaptic death of granule cells (GC) and inferior olivary (IO) neurones. The relative contribution of these pathways can only be assessed from their momentary involvement at any stage of the complete course of neurodegeneration. Here we used quantitative labelling for activated caspase-3 (Casp-3) and Fluoro-Jade B (FJ-B) to investigate the spatio-temporal pattern of neuronal death from P6 to P67 in Lc/+ mutants. Activated Casp-3 was present only in narrow time intervals (P14 to P22 in PCs; P14 to P28 in GCs) and in small subpopulations of PCs, GCs, and IO neurones. FJ-B positive PCs were detected during a broader period (P14 to P28), and outnumbered Casp-3 labelled PCs by a factor exceeding eight. Nevertheless, FJ-B labelling was restricted to PCs and never found in either GC or IO neurones. In conclusion, we present the first complete time course and extent of Casp-3 activation in Lc/+ mutants and show that the majority of dying neurones in Lc/+ mutants undergo Casp-3 independent cell death. The cellular overload produced by the initial gene defect in Lc/+ mutants apparently activates a variety of apoptotic and non-apoptotic pathways within the same neuronal population. Moreover, we present the first evidence for the ability of FJ-B to selectively label a discrete population of dying PCs, implying a higher selectivity of FJ-B than previously supposed.
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Affiliation(s)
- Jörg Bäurle
- Campus Benjamin Franklin, Department of Physiology, Charité-Universitätsmedizin Berlin, Arnimallee 22, 14195, Berlin, Germany.
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15
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Seoane A, Apps R, Balbuena E, Herrero L, Llorens J. Differential effects oftrans-crotononitrile and 3-acetylpyridine on inferior olive integrity and behavioural performance in the rat. Eur J Neurosci 2005; 22:880-94. [PMID: 16115211 DOI: 10.1111/j.1460-9568.2005.04230.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The inferior olive climbing fibre projection is key to cerebellar contributions to motor control. Here we present evidence for a novel tool, trans-crotononitrile (TCN), to selectively inactivate the olive to study its functions. Anatomical, electrophysiological and behavioural techniques have been used in rats to assess the CNS effects of TCN, with a focus on the olivocerebellar projection. These findings were compared with those obtained with 3-acetylpyridine (plus nicotinamide administered 3.5 h later, 3AP + 3.5 h). Fluoro-Jade B cell labelling showed that TCN and 3AP + 3.5 h induce neurodegeneration primarily within the inferior olive, with no other targets in common. Recordings of evoked field potentials on the cerebellar cortical surface showed that both neurotoxins can reduce transmission in climbing fibre but not mossy fibre pathways. Both histological and electrophysiological differences suggest that TCN and 3AP have distinct mechanisms of action. Estimates of the numbers of surviving cells within individual subdivisions of the olive indicate that TCN and 3AP + 3.5 h cause different patterns of subtotal olivary lesion: most surviving neurons are present in the rostral (TCN) or caudal (3AP + 3.5 h) parts of the medial accessory olive, which are associated with two different cerebellar modules: the C2 and A modules, respectively. In behavioural studies, TCN and 3AP + 3.5 h produced differences in motor deficits consistent with the notion that these cerebellar modules have distinct functional responsibilities. Thus, studies using TCN as compared with 3AP + 3.5 h have the potential to shed light on the contributions of different cerebellar modules in motor control.
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Affiliation(s)
- A Seoane
- Department of Physiology, School of Medical Sciences, University of Bristol, UK
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16
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Nahm SS, Jung KY, Enger MK, Griffith WH, Abbott LC. Differential expression of T-type calcium channels in P/Q-type calcium channel mutant mice with ataxia and absence epilepsy. ACTA ACUST UNITED AC 2005; 62:352-60. [PMID: 15514988 DOI: 10.1002/neu.20107] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutations in P/Q-type calcium channels generate common phenotypes in mice and humans, which are characterized by ataxia, paroxysmal dyskinesia, and absence seizures. Subsequent functional changes of T-type calcium channels in thalamus are observed in P/Q-type calcium channel mutant mice and these changes play important roles in generation of absence seizures. However, the changes in T-type calcium channel function and/or expression in the cerebellum, which may be related to movement disorders, are still unknown. The leaner mouse exhibits severe ataxia, paroxysmal dyskinesia, and absence epilepsy due to a P/Q-type calcium channel mutation. We investigated changes in T-type calcium channel expression in the leaner mouse thalamus and cerebellum using quantitative real-time polymerase chain reaction (qRT-PCR) and quantitative in situ hybridization histochemistry (ISHH). qRT-PCR analysis showed no change in T-type calcium channel alpha 1G subunit (Cav3.1) expression in the leaner thalamus, but a significant decrease in alpha 1G expression in the whole leaner mouse cerebellum. Interestingly, quantitative ISHH revealed differential changes in alpha 1G expression in the leaner cerebellum, where the granule cell layer showed decreased alpha 1G expression while Purkinje cells showed increased alpha 1G expression. To confirm these observations, the granule cell layer and the Purkinje cell layer were laser capture microdissected separately, then analyzed with qRT-PCR. Similar to the observation obtained by ISHH, the leaner granule cell layer showed decreased alpha 1G expression and the leaner Purkinje cell layer showed increased alpha 1G expression. These results suggest that differential expression of T-type calcium channels in the leaner cerebellum may be involved in the observed movement disorders.
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MESH Headings
- Analysis of Variance
- Animals
- Animals, Newborn
- Ataxia/complications
- Ataxia/genetics
- Ataxia/metabolism
- Autoradiography/methods
- Calcium Channels, P-Type/genetics
- Calcium Channels, Q-Type/genetics
- Calcium Channels, T-Type/genetics
- Calcium Channels, T-Type/metabolism
- Cerebellum/cytology
- Cerebellum/metabolism
- Disease Models, Animal
- Epilepsy, Absence/complications
- Epilepsy, Absence/metabolism
- Female
- Gene Expression Regulation, Developmental/genetics
- In Situ Hybridization/methods
- Lasers
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Neurologic Mutants
- Microdissection/methods
- Mutation
- Neurons/metabolism
- Protein Subunits/genetics
- Protein Subunits/metabolism
- RNA, Messenger/biosynthesis
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Thalamus/cytology
- Thalamus/metabolism
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Affiliation(s)
- Sang-Soep Nahm
- Department of Human Anatomy & Medical Neurobiology, College of Medicine, Texas A&M University System Health Science Center, College Station, Texas 77843-1114, USA
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17
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Fernandes AMAP, Maurer-Morelli CV, Campos CBL, Mello MLS, Castilho RF, Langone F. Fluoro-Jade, but not Fluoro-Jade B, stains non-degenerating cells in brain and retina of embryonic and neonatal rats. Brain Res 2005; 1029:24-33. [PMID: 15533312 DOI: 10.1016/j.brainres.2004.09.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2004] [Indexed: 11/15/2022]
Abstract
Fluoro-Jade (FJ) and Fluoro-Jade B (FJB) are fluorescein derivatives currently used to stain brain cells under degeneration. In this study, we investigated the FJ staining of nondegenerating cells in embryonic and neonatal rat brain and retina. In embryonic rat brain (embryonic day 15; E15), very intense staining of cells was observed. The number of FJ-stained cells and the intensity of staining decreased with increasing in animal age, being almost absent by postnatal day 16 (P16). Only a few cells in neonatal rat brain were in the process of cell death, as verified by the TUNEL technique. The FJ-stained cells in neonatal brain were positive for the neuronal marker neuronal nuclei antigen (NeuN). In retina, FJ stained mainly cells from the ganglion cell layer at P2 and the neuroblastic layer at P2 and P6. In contrast to FJ, FJB did not stain nondegenerating cells in embryonic and neonatal rats. These results show that in addition to staining degenerating brain cells, FJ also stains nondegenerating central nervous system cells in embryonic and neonatal stages.
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Affiliation(s)
- Anna M A P Fernandes
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, 13083-970, Brazil
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18
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Zanjani H, Herrup K, Mariani J. Cell number in the inferior olive of nervous and leaner mutant mice. J Neurogenet 2004; 18:327-39. [PMID: 15370195 DOI: 10.1080/01677060390449482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Naturally occurring cell death is an important feature of neuronal network development: the absence of adequate postsynaptic target neurons during a critical period may result in the death of presynaptic neurons, the degree of death varying inversely with the size of the target population. Studies of mouse mutants with abnormal cerebellar development provide support for this neuron/target relationship in circuits within the CNS. In the present study we analysed the inferior olivary cell population in two cerebellar mutant mice, nervous (nr/nr) and leaner (Cacna1ala/la). In these mice Purkinje cell degeneration begins near the end of the first postnatal month. In nervous mice the loss starts at postnatal day 20 (P20) and by the end of second month almost 90% of the Purkinje cells in the hemisphere and 50% in the vermis have disappeared. In leaner mice Purkinje cell loss starts after P30 and by P60 almost 50% of these cells are lost. We report here a loss of one third of inferior olivary neurons in the nervous mutation while the entire population appears intact in the leaner mouse. These results allow better definition of the end of the period of target dependency of inferior olive neurons. Their implications for the cell-cell interactions in the developing olivo-cerebellar system are discussed.
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Affiliation(s)
- Hadi Zanjani
- Laboratoire Développement et Vieillissement du Système Nerveux, CNRS et Université P. et M. Curie, Paris, France.
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19
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Abbott LC, Nahm SS. Neuronal nitric oxide synthase expression in cerebellar mutant mice. THE CEREBELLUM 2004; 3:141-51. [PMID: 15543804 DOI: 10.1080/14734220410031927] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Nitric oxide (NO) is a diffusible, multifunctional signaling molecule found in many areas of the brain. NO signaling is involved in a wide array of neurophysiological functions including synaptogenesis, modulation of neurotransmitter release, synaptic plasticity, central nervous system blood flow and cell death. NO synthase (NOS) activity regulates the production of NO and the cerebellum expresses high levels of nitric oxide synthase (NOS) in granule, stellate and basket cells. Cerebellar mutant mice provide excellent opportunities to study changes of NO/NOS concentrations and activities to gain a greater understanding of the roles of NO and NOS in cerebellar function. Here, we have reviewed the current understanding of the functional roles of NO and NOS in the cerebellum and present NO/NOS activities that have been described in various cerebellar mutant mice and NOS knockout mice. NO appears to exert neuroprotective effects at low to moderate concentrations, whereas NO becomes neurotoxic as the concentration increases. Excessive NO production can cause oxidative stress to neurons, ultimately impairing neuronal function and result in neuronal cell death. Based on their genetics and cerebellar histopathology, some of cerebellar mutant mice display similarities with human neurological conditions and may prove to be valuable models to study several human neurological disorders, such as autism and schizophrenia.
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Affiliation(s)
- Louise C Abbott
- Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station, Texas 77843-4458, USA.
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20
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Nahm SS, Frank TC, Browning MD, Sepulvado JM, Hiney JK, Abbott LC. Insulin-like growth factor-I improves cerebellar dysfunction but does not prevent cerebellar neurodegeneration in the calcium channel mutant mouse, leaner. Neurobiol Dis 2004; 14:157-65. [PMID: 14572439 DOI: 10.1016/s0969-9961(03)00106-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The effects of insulin-like growth factor-I (IGF-I) on cerebellar dysfunction and neurodegeneration were investigated in leaner mice, which exhibit cerebellar ataxia and neurodegeneration related to P/Q-type calcium channel mutations. Leaner mice showed significantly reduced serum and cerebellar IGF-I concentrations compared to wild-type mice at postnatal day 30. Behavioral assessment of leaner mice injected with IGF-I subcutaneously for 4 weeks showed partially improved cerebellar function. Histological analysis of IGF-I treated leaner cerebella showed no difference in the number of dying Purkinje cells compared to control leaner cerebella. These results further support potential use of IGF-I as a therapeutic aid for cerebellar ataxia related to calcium channel mutations. Nonetheless, IGF-I administration does not rescue dying cerebellar neurons, which suggests that the beneficial effects of IGF-I may have been achieved through surviving cerebellar neurons.
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Affiliation(s)
- Sang-Soep Nahm
- Department of Veterinary Anatomy & Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4458, USA
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21
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Lau FC, Frank TC, Nahm SS, Stoica G, Abbott LC. Postnatal apoptosis in cerebellar granule cells of homozygous leaner (tg1a/tg1a) mice. Neurotox Res 2004; 6:267-80. [PMID: 15545010 DOI: 10.1007/bf03033437] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Leaner mice carry a homozygous, autosomal recessive mutation in the mouse CACNA1A gene encoding the Alpha1A subunit of P/Q-type calcium channels, which results in an out-of-frame splicing event in the carboxy terminus of the Alpha1A protein. Leaner mice exhibit severe ataxia, paroxysmal dyskinesia and absence seizures. Functional studies have revealed a marked decrease in calcium currents through leaner P/Q-type channels and altered neuronal calcium ion homeostasis in cerebellar Purkinje cells. Histopathological studies of leaner mice have revealed extensive postnatal cerebellar Purkinje and granule cell loss. We examined the temporospatial pattern of cerebellar granule cell death in the leaner mouse between postnatal days (P) 10 and 40. Our observations clearly indicate that leaner cerebellar granule cells die via an apoptotic process and that the peak time of neuronal death is P20. We did not observe a significant increase in microglial and astrocytic responses at P20, suggesting that glial responses are not a cause of neuronal cell death. We propose that the leaner cerebellar granule cell represents an in vivo animal model for low intracellular [Ca2+]-induced apoptosis. Since intracellular [Ca2+] is critical in the control of gene expression, it is quite likely that reduced intracellular [Ca2+] could activate a lethal cascade of altered gene expression leading to the apoptotic granule cell death in the leaner cerebellum.
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Affiliation(s)
- Francis C Lau
- USDA, HNRCA, Tufts University, 711 Washington St., Boston, MA 02111, USA
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