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Traumatic brain injury (TBI) is one of the leading causes of death worldwide. There are currently no effective treatments for TBI, and trauma survivors suffer from a variety of long-lasting health consequences. With nutritional support recently emerging as a vital step in improving TBI patients' outcomes, we sought to evaluate the potential therapeutic benefits of nutritional supplements derived from bovine thymus gland, which can deliver a variety of nutrients and bioactive molecules. In a rat model of controlled cortical impact (CCI), we determined that animals supplemented with a nuclear fraction of bovine thymus (TNF) display greatly improved performance on beam balance and spatial memory tests following CCI. Using RNA-Seq, we identified an array of signaling pathways that are modulated by TNF supplementation in rat hippocampus, including those involved in the process of autophagy. We further show that bovine thymus-derived extracts contain antigens found in neural tissues and that supplementation of rats with thymus extracts induces production of serum IgG antibodies against neuronal and glial antigens, which may explain the enhanced animal recovery following CCI through possible oral tolerance mechanism. Collectively, our data demonstrate, for the first time, the potency of a nutritional supplement containing nuclear fraction of bovine thymus in enhancing the functional recovery from TBI.
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Lesões Encefálicas Traumáticas , Extratos do Timo , Humanos , Ratos , Animais , Bovinos , Extratos do Timo/farmacologia , Extratos do Timo/uso terapêutico , Lesões Encefálicas Traumáticas/tratamento farmacológico , Neurônios , Neuroglia , Hipocampo , Modelos Animais de DoençasRESUMO
OBJECTIVES: Inadequate dietary magnesium (Mg) intake is a growing public health concern. Mg is critical for diverse metabolic processes including energy production, macromolecule biosynthesis, and electrolyte homeostasis. Inadequate free Mg2+ ion concentration ([Mg2+]) in the brain is associated with several neurological and behavioral disorders. Elevating [Mg2+]in the brain using oral Mg supplementation has proven to be challenging due to the tight regulation of Mg2+ transport to the brain. This study explored the effect of short-term moderate reduction in dietary Mg intake (87% of normal Mg diet for 30 days) on [Mg2+] in the cerebrospinal fluid (CSF) ([Mg2+]CSF) and red blood cells (RBCs) ([Mg2+]RBC) in adult male rats. In addition, we investigated the effectiveness of magnesium-rich blend of Swiss chard and buckwheat extracts (SC/BW extract) in increasing brain [Mg2+] compared to various Mg salts commonly used as dietary supplements. METHODS: Animals were assigned to either normal or low Mg diet for 30 - 45 days. Following this, animals maintained on low Mg diet were supplemented with various Mg compounds. [Mg2+]CSF and [Mg2+]RBC were measured at baseline and following Mg administration. Anxiety-like behavior and cognitive function were also evaluated. RESULTS: The present study showed that a short-term and moderate reduction in Mg dietary intake results in a significant decline in [Mg2+]CSF and [Mg2+]RBC and the emergence of anxiety-like behavior in comparison to animals maintained on normal Mg diet. Supplementation with SC/BW extract significantly elevated [Mg2+]CSF and improved animal performance in the novel object recognition test in comparison with animals maintained on reduced Mg intake and supplemented with various Mg compounds. DISCUSSION: These observations indicate that brain [Mg2+] is more sensitive to a short-term and moderate reduction in Mg dietary intake than previously thought and emphasizes the importance of dietary Mg in replenishing brain Mg2+ reserves.
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Beta vulgaris , Fagopyrum , Animais , Masculino , Ratos , Magnésio , Fagopyrum/metabolismo , Beta vulgaris/metabolismo , Dieta , Suplementos Nutricionais , Ingestão de Alimentos , Encéfalo/metabolismo , Modelos Animais de DoençasRESUMO
A number of mouse models for spinal muscular atrophy (SMA) have been genetically engineered to recapitulate the severity of human SMA by using a targeted null mutation at the mouse Smn1 locus coupled with the transgenic addition of varying copy numbers of human SMN2 genes. Although this approach has been useful in modeling severe SMA and very mild SMA, a mouse model of the intermediate form of the disease would provide an additional research tool amenable for drug discovery. In addition, many of the previously engineered SMA strains are multi-allelic by design, containing a combination of transgenes and targeted mutations in the homozygous state, making further genetic manipulation difficult. A new genetic engineering approach was developed whereby variable numbers of SMN2 sequences were incorporated directly into the murine Smn1 locus. Using combinations of these alleles, we generated an allelic series of SMA mouse strains harboring no, one, two, three, four, five, six or eight copies of SMN2. We report here the characterization of SMA mutants in this series that displayed a range in disease severity from embryonic lethal to viable with mild neuromuscular deficits.
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Atrofia Muscular Espinal/genética , Junção Neuromuscular/genética , Alelos , Animais , Comportamento Animal , Modelos Animais de Doenças , Genótipo , Humanos , Camundongos , Camundongos Endogâmicos , Junção Neuromuscular/metabolismo , Fenótipo , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Proteína 2 de Sobrevivência do Neurônio Motor/metabolismoRESUMO
Background: Persistent accumulation and hindered clearance of toxins from tissues over time may promote the development and exacerbation of several diseases. Hepatic metabolic detoxification is a key physiological process responsible for the clearance of toxic substances from the body. A healthy diet with nutritional dietary supplementation may support metabolic detoxification and help mitigate the negative effects of toxin burden. Methods: A multicenter, randomized, single-blind, controlled trial was conducted to test the effects of a dietary detoxification product (detox; n = 20) versus an active dietary control product (active control; n = 20) on selected biomarkers of metabolic detoxification, general health, and well-being following 28 days of dietary supplementation. Study participants displayed multiple symptoms commonly associated with elevated toxin burden, but otherwise healthy. Results: The detox group displayed significantly decreased levels of red blood cell total toxic metals, decreased urine total porphyrins, and decreased urine mutagenicity potency compared with baseline. Both the detox and active control groups showed improvements in the symptoms attributed to elevated toxin burden. Fatigue and sleep disruption scores were significantly reduced in the detox group compared with baseline. No significant differences in anthropometric measures and vital signs, and no adverse events or side effects were detected in either group over the study period. Conclusions: This study demonstrates the benefit of nutritional intervention for supporting metabolic detoxification, evidenced by significant changes in multiple detoxification biomarkers and improvement in questionnaire scores related to quality of life, general health, and well-being.
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A-F Betafood® is a whole food-based health product. The product contains phytonutrients and bioactives with antioxidant properties that may support gallbladder and liver function. Herein, we investigated the efficacy of A-F Betafood® on gallbladder and liver function. In this randomized, placebo-controlled, parallel study fifty overweight but otherwise healthy adults received A-F Betafood® or placebo for 12 weeks. Gallbladder function as assessed by gallbladder volume, ejection fraction (GBEF), ejection rate, wall thickness and liver function determined via aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase, and high-sensitivity c-reactive protein analysis at baseline and week 12 were the primary outcomes. Total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triglycerides, and oxidative stress markers including oxidized low-density lipoprotein, tumor necrosis factor-α, adiponectin and malonyldialdehyde (MDA) were assessed as secondary outcomes. A-F Betafood®-supplementation significantly reduced gallbladder wall thickness (p = 0.049) by 9% compared to placebo from baseline to week 12. The A-F Betafood® group alone had significant improvements in gallbladder volume (32%; p = 0.044) and GBEF (19%; p = 0.047) at week 12. There were no changes in liver function, oxidative stress markers or blood lipid concentrations, though MDA concentrations decreased in both groups. Our findings demonstrate A-F Betafood®-supplementation significantly improves measures of gallbladder function and support healthy gallbladder function in the individuals with gall bladder condition.
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Suplementos Nutricionais , Doenças da Vesícula Biliar/prevenção & controle , Sobrepeso/terapia , Compostos Fitoquímicos/administração & dosagem , Adulto , Idoso , Alanina Transaminase/sangue , Antioxidantes/administração & dosagem , Aspartato Aminotransferases/sangue , Biomarcadores/sangue , Proteína C-Reativa/análise , Colesterol/sangue , Método Duplo-Cego , Feminino , Vesícula Biliar/fisiopatologia , Doenças da Vesícula Biliar/etiologia , Humanos , Lipídeos/sangue , Fígado/fisiopatologia , Masculino , Malondialdeído/sangue , Pessoa de Meia-Idade , Sobrepeso/complicações , Sobrepeso/fisiopatologia , Estresse Oxidativo , gama-Glutamiltransferase/sangueRESUMO
Proteomics monitoring of an elite adventure athlete (age 33 years) was conducted over a 28-week period that culminated in the successful, solo, unassisted, and unsupported two month trek across the Antarctica (1500 km). Training distress was monitored weekly using a 19-item, validated training distress scale (TDS). Weekly dried blood spot (DBS) specimens were collected via fingerprick blood drops onto standard blood spot cards. DBS proteins were measured with nano-electrospray ionization liquid chromatography tandem mass spectrometry (nanoLC-MS/MS) in data-independent acquisition (DIA) mode, and 712 proteins were identified and quantified. The 28-week period was divided into time segments based on TDS scores, and a contrast analysis between weeks five and eight (low TDS) and between weeks 20 and 23 (high TDS, last month of Antarctica trek) showed that 31 proteins (n = 20 immune related) were upregulated and 35 (n = 17 immune related) were downregulated. Protein-protein interaction (PPI) networks supported a dichotomous immune response. Gene ontology (GO) biological process terms for the upregulated immune proteins showed an increase in regulation of the immune system process, especially inflammation, complement activation, and leukocyte mediated immunity. At the same time, GO terms for the downregulated immune-related proteins indicated a decrease in several aspects of the overall immune system process including neutrophil degranulation and the antimicrobial humoral response. These proteomics data support a dysfunctional immune response in an elite adventure athlete during a sustained period of mental and physical distress while trekking solo across the Antarctica.
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Huntington's disease (HD) is one of the few neurodegenerative diseases with a known genetic cause, knowledge that has enabled the creation of animal models using genetic manipulations that aim to recapitulate HD pathology. The study of behavioral and neuropathological phenotypes of these HD models, however, has been plagued by inconsistent results across laboratories stemming from the lack of standardized husbandry and testing conditions, in addition to the intrinsic differences between the models. We have compared different HD models using standardized conditions to identify the most robust phenotypic differences, best suited for preclinical therapeutic efficacy studies. With a battery of tests of sensory-motor function, such as the open field and prepulse inhibition tests, we replicate previous results showing a strong and progressive behavioral deficit in the R6/2 line with an average of 129 CAG repeats in a mixed CBA/J and C57BL/6J background. We present the first behavioral characterization of a new model, an R6/2 line with an average of 248 CAG repeats in a pure C57BL/6J background, which also showed a progressive and robust phenotype. The BACHD in a FVB/N background showed robust and progressive behavioral phenotype, while the YAC128 full-length model on either an FVB/N or a C57BL/6J background generally showed milder deficits. Finally, the Hdh(Q111) knock-in mouse on a CD1 background showed very mild deficits. This first extensive standardized cross-characterization of several HD animal models under standardized conditions highlights several behavioral outcomes, such as hypoactivity, amenable to standardized preclinical therapeutic drug screening.
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Comportamento Animal , Modelos Animais de Doenças , Doença de Huntington , Atividade Motora , Envelhecimento , Animais , Feminino , Técnicas de Introdução de Genes , Genótipo , Humanos , Proteína Huntingtina , Doença de Huntington/genética , Masculino , Camundongos , Camundongos Transgênicos , Atividade Motora/genética , Proteínas do Tecido Nervoso/genética , Testes Neuropsicológicos , Proteínas Nucleares/genética , Fenótipo , Caracteres SexuaisRESUMO
IMPORTANCE: Epigenetic modifications of the genome, such as DNA methylation and histone modifications, have been reported to play a role in neurodegenerative diseases (ND) such as Alzheimer's disease (AD) and Parkinson's disease (PD). OBJECTIVE: To systematically review studies investigating epigenetic marks in AD or PD. METHODS: Eleven bibliographic databases (Embase.com, Medline (Ovid), Web-of-Science, Scopus, PubMed, Cinahl (EBSCOhost), Cochrane Central, ProQuest, Lilacs, Scielo and Google Scholar) were searched until July 11th 2016 to identify relevant articles. We included all randomized controlled trials, cohort, case-control and cross-sectional studies in humans that examined associations between epigenetic marks and ND. Two independent reviewers, with a third reviewer available for disagreements, performed the abstract and full text selection. Data was extracted using a pre-designed data collection form. RESULTS: Of 6,927 searched references, 73 unique case-control studies met our inclusion criteria. Overall, 11,453 individuals were included in this systematic review (2,640 AD and 2,368 PD outcomes). There was no consistent association between global DNA methylation pattern and any ND. Studies reported epigenetic regulation of 31 genes (including cell communication, apoptosis, and neurogenesis genes in blood and brain tissue) in relation to AD and PD. Methylation at the BDNF, SORBS3 and APP genes in AD were the most consistently reported associations. Methylation of α-synuclein gene (SNCA) was also found to be associated with PD. Seven studies reported histone protein alterations in AD and PD. CONCLUSION: Many studies have investigated epigenetics and ND. Further research should include larger cohort or longitudinal studies, in order to identify clinically significant epigenetic changes. Identifying relevant epigenetic changes could lead to interventional strategies in ND.
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Metilação de DNA , Histonas/química , Doenças Neurodegenerativas/genética , Doença de Alzheimer/genética , Viés , Estudos Transversais , Epigênese Genética , Genoma Humano , Código das Histonas , Humanos , Inflamação , Doença de Parkinson/genética , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
There is growing evidence that programmed cell death may play a role in degenerative neurologic disease. The caspases are a family of cell death proteins that mediate proteolytic cascades in the death process. Although there is clear evidence that caspases play a role in the destruction of the components of the neuronal soma, it has been controversial whether they play a role in the degeneration of axons that accompanies the death of the cell body. It is important to define the molecular mechanisms of axonal degeneration, because terminal degeneration may occur early in neurodegenerative disease. We have therefore investigated whether caspases play a role in axonal degeneration in the dopaminergic nigrostriatal system following axotomy of the median forebrain bundle during development. We find that this lesion induces apoptosis in midbrain dopaminergic neurons at the level of the cell soma. Concomitantly with this induction of apoptosis, degeneration of dopaminergic axons occurs and is characterized by the formation of axonal swellings and spheroids. Immunohistochemical analysis reveals that the activated form of caspase-3 and a caspase cleavage product of beta-actin are abundantly expressed in these degenerating fibers. We conclude that caspases are activated in degenerating dopaminergic axons as the somata undergo programmed cell death in this model. These results raise the possibility that caspase activation may occur in other programmed cell death contexts for these neurons, and, if this is so, then their inhibition may be a useful therapeutic target.
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Apoptose/fisiologia , Caspases/biossíntese , Dopamina/fisiologia , Feixe Prosencefálico Mediano/fisiopatologia , Degeneração Neural/fisiopatologia , Substância Negra/fisiopatologia , Animais , Animais Recém-Nascidos , Axônios/enzimologia , Axônios/patologia , Axotomia , Caspase 3 , Imuno-Histoquímica , Feixe Prosencefálico Mediano/enzimologia , Feixe Prosencefálico Mediano/crescimento & desenvolvimento , Degeneração Neural/enzimologia , Degeneração Neural/etiologia , Ratos , Ratos Sprague-Dawley , Substância Negra/enzimologia , Substância Negra/crescimento & desenvolvimentoRESUMO
This study investigated whether mild birth complications (C-section birth, C-section + 15 min global anoxia) interact with stress at adulthood to modulate levels of [3H]WIN 35428 binding to dopamine transporters (DAT) in rat brain. Without stress, adult C-sectioned rats showed increased DAT binding in the dorsal striatum and nucleus accumbens core compared to vaginal birth, while anoxic rats showed increased DAT binding in cingulate and infralimbic cortices. Stress at adulthood had differential effects on DAT binding in the three birth groups. Thus, after repeated tail pinch stress at adulthood, DAT binding was significantly lower in the nucleus accumbens in both the C-section group and the anoxic group, compared to vaginal birth. It is concluded that a history of birth complications can alter the manner in which DAT is regulated by stress in the adult rat brain.
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Envelhecimento/metabolismo , Encéfalo/metabolismo , Cesárea/efeitos adversos , Cocaína/análogos & derivados , Hipóxia Fetal/complicações , Glicoproteínas de Membrana , Proteínas de Membrana Transportadoras/metabolismo , Proteínas do Tecido Nervoso , Estresse Fisiológico/complicações , Estresse Fisiológico/metabolismo , Animais , Cocaína/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina , Inibidores da Captação de Dopamina/metabolismo , Ratos , Ratos Sprague-Dawley , Valores de ReferênciaRESUMO
Serotonin is an important modulator of anxiety and thus drugs that act on this system have frequently been shown to be either anxiogenic or anxiolytic. In addition serotonin has important trophic functions during early development and disruption of serotonin homeostasis is likely to have long-lasting repercussions in the adult. In the present study we examined the contribution of two serotonin receptor subtypes (5HT(1A) and 5HT(1B)) to the pathophysiology of anxiety during development. For this, we have studied homozygous knockout mice lacking the 5HT(1B) receptor and examined the effect of pharmacological manipulations of 5HT(1A) and 5HT(1B) receptors on locomotor activity and emission of ultrasonic vocalization (USV) in 7-8 days old mice. As shown before, drug naïve 5HT(1B) knockout pups showed reduced USV and were hyperactive, in comparison to wild type controls. The administration of RU24969 (a 5HT(1A/1B) agonist) showed a dose-dependent decrease in USV in the wild type and a biphasic effect in the mutants and resulted in dose-dependent increase in activity in the wild type and, to a lesser extent, in the knockouts. The selective 5HT(1A) agonist, 8OH-DPAT, dose-dependently blocked vocalization in both genotypes and also increased locomotion. To differentially activate 5HT(1B) receptors we first blocked 5HT(1A) receptors with WAY100315 and then treated with RU24969. At a high testing temperature, pretreatment with WAY100315 resulted in an anxiogenic effect in wild type pups but not in the knockouts. In agreement with our findings that 5HT(1B) knockout mice were in general less sensitive to 5HT(1A) activation, 5HT(1A) receptor binding was reduced in the knockouts in comparison to controls. Finally, treatment with diazepam dose-dependently decreased USVs in both group with the knockouts showing enhanced sensitivity to this drug. Our results show that important adaptations to a disturbance of serotonin homeostasis occur during the first week of life within the serotonergic system. The observed decreased in sensitivity of 5HT(1B) knockout mice to 5HT(1A) and increased to GABA(A) manipulations are discussed within the context of serotonergic plasticity during development and the implication for clinical treatment of anxiety in genetically predisposed individuals.
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Comportamento Animal/fisiologia , Receptor 5-HT1A de Serotonina/metabolismo , Receptor 5-HT1B de Serotonina/deficiência , Agonistas do Receptor 5-HT1 de Serotonina , Agonistas do Receptor de Serotonina/farmacologia , Vocalização Animal/fisiologia , Animais , Animais Recém-Nascidos , Comportamento Animal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Camundongos , Vocalização Animal/efeitos dos fármacosRESUMO
Phenotyping with traditional behavioral assays constitutes a major bottleneck in the primary screening, characterization, and validation of genetic mouse models of disease, leading to downstream delays in drug discovery efforts. We present a novel and comprehensive one-stop approach to phenotyping, the PhenoCube™. This system simultaneously captures the cognitive performance, motor activity, and circadian patterns of group-housed mice by use of home-cage operant conditioning modules (IntelliCage) and custom-built computer vision software. We evaluated two different mouse models of Huntington's Disease (HD), the R6/2 and the BACHD in the PhenoCube™ system. Our results demonstrated that this system can efficiently capture and track alterations in both cognitive performance and locomotor activity patterns associated with these disease models. This work extends our prior demonstration that PhenoCube™ can characterize circadian dysfunction in BACHD mice and shows that this system, with the experimental protocols used, is a sensitive and efficient tool for a first pass high-throughput screening of mouse disease models in general and mouse models of neurodegeneration in particular.
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Homozygosis for the rd1 mutation in the Pbe6b gene results in the loss of the rod beta-subunit of the cyclic GMP phosphodiesterase and, eventually, of all rod and cone photoreceptors. The R6/2 mouse line is a widely used model of Huntington's disease (HD). The original line was made available on a mixed background obtained by crossing, via ovarian transplant, female R6/2 (on a B6CBA mixed background) with male B6CBAF1/J mice. As the CBA/J strain used in the US is homozygous for the rd1 mutation and the breeding scheme does not ensure heterozygosis for the mutation, a significant percentage of the offspring on this mixed background is expected to be homozygous for the rd1 mutation. We investigate here the effect of rd1 homozygosis on motor function and examined the effects of the mutation on the R6/2 phenotype. Homozygosis for the rd1 mutation resulted in increased activity in the open field test and reduced rotarod test performance. In addition, rd1 mutation absence or heterozygosis reduced the differences between the R6/2 and the WT mice. Our recommendation for the neurodegeneration field, and for all mouse studies in general, is to carefully control homozygosis for retinal degeneration mutation, even when using tests of motor function.
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The discovery of upregulated glycogen synthase kinase-3 (GSK-3) in various pathological conditions has led to the development of a host of chemically diverse small molecule GSK-3 inhibitors, such as BIP-135. GSK-3 inhibition emerged as an alternative therapeutic target for treating spinal muscular atrophy (SMA) when a number of GSK-3 inhibitors were shown to elevate survival motor neuron (SMN) levels in vitro and to rescue motor neurons when their intrinsic SMN level was diminished by SMN-specific short hairpin RNA (shRNA). Despite their cellular potency, the in vivo efficacy of GSK-3 inhibitors has yet to be evaluated in an animal model of SMA. Herein, we disclose that a potent and reasonably selective GSK-3 inhibitor, namely BIP-135, was tested in a transgenic Δ7 SMA KO mouse model of SMA, and found to prolong the median survival of these animals. In addition, this compound was shown to elevate the SMN protein level in SMA patient-derived fibroblast cells as determined by western blot, and was neuroprotective in a cell-based, SMA-related model of oxidative stress-induced neurodegeneration.
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Proximal Spinal Muscular Atrophy (SMA) is a debilitating neuromuscular disease and a leading inherited genetic cause of infant death. To date, there is no effective treatment for SMA. The SMNΔ7 neonatal mouse model of SMA recapitulates key features of the severe form of SMA and remains a valuable tool in preclinical drug discovery. At any particular postnatal age (P), the disease progression in the SMNΔ7 mouse model is not universal, as some animals die as early as the day of birth and others live for up to three weeks. Identification of the disease stage in SMNΔ7 mice, independent of age, would aid in the design and interpretation of preclinical studies. We developed a score (CD score), derived from body weight analysis, that allowed us to gain insight into the disease progression and predict death. Respiratory complication is a leading cause of mortality in the SMA patient and this phenotype has been reported in severe mouse models of SMA. We subsequently measured muscle and brain tissue lactate levels, an indirect measure of hypoxia, in SMNΔ7 mice at P10 and correlated these measures to respiratory rate. SMNΔ7 mice showed a significant increase in tissue lactate and a decrease in respiratory rate in comparison to control. The CD score correlates linearly with tissue lactate level and respiratory rate. The finding of lactate buildup in the SMNΔ7 mouse and the correlation with a score that is predictive of disease stage provide an interesting insight into the disease pathophysiology and a possible biomarker for SMA.
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Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/mortalidade , Mutação/genética , Proteína 2 de Sobrevivência do Neurônio Motor/genética , Fatores Etários , Animais , Animais Recém-Nascidos , Peso Corporal/genética , Encéfalo/patologia , Simulação por Computador , Ácido Dicloroacético/uso terapêutico , Modelos Animais de Doenças , Progressão da Doença , Feminino , Genótipo , Humanos , Ácido Láctico/metabolismo , Masculino , Camundongos , Camundongos Knockout , Músculo Esquelético/metabolismo , Atrofia Muscular Espinal/tratamento farmacológico , Valor Preditivo dos Testes , Análise de Sobrevida , Proteína 2 de Sobrevivência do Neurônio Motor/deficiênciaRESUMO
Spinal muscular atrophy (SMA) is characterized by selective loss of alpha-motor neurons and is caused by homozygous loss or mutation in the survival motor neuron (SMN1) gene. Loss of SMN1 is partially compensated by the copy gene, SMN2. Currently, there are no specific treatments for SMA. Key features of SMA are modeled in mice by deletion of murine Smn, and insertion of both full length human SMN2 gene and the major aberrant splice isoform of the SMN2 gene (SMNDelta7; [Le, T.T., Pham, L.T., Butchbach, M.E., Zhang, H.L., Monani, U.R., Coovert, D.D., Gavrilina, T.O., Xing, L., Bassell, G.J., and Burghes, A.H. 2005. SMNDelta7, the major product of the centromeric survival motor neuron (SMN2) gene, extends survival in mice with spinal muscular atrophy and associates with full-length SMN. Hum Mol Genet 14: 845-857]). The present study identified moderate-throughput, quantitative behavioral tests in neonatal SMN2(+/+);SMNDelta7(+/+);Smn(-/-) mice. It also addresses methodological approaches and common interpretational challenges in a neonatal model with motor deficiencies and frequent deaths. Animals were assessed daily for body weight and survival, and every other day for neonatal well-being indices and tests of motor function such as performance on the hind-limb suspension test (a.k.a. tube test) and geotaxis. The tube test is a novel non-invasive motor function test specifically designed for neonatal rodents. We found progressive deterioration in SMA model mice for most measures studied particularly body weight, survival, body temperature and motor function with differences appearing as early as P3. Power analysis showed that body weight, survival, righting reflex, geotaxis and tube test had highest predictive power for drug efficacy studies. This multi-functional component battery of tests provides a rapid and efficient means to identify, evaluate and develop candidate therapies as a prelude to human clinical trials.
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Avaliação Pré-Clínica de Medicamentos/métodos , Atrofias Musculares Espinais da Infância/tratamento farmacológico , Animais , Animais Recém-Nascidos , Peso Corporal/efeitos dos fármacos , Peso Corporal/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Transtornos dos Movimentos/diagnóstico , Transtornos dos Movimentos/tratamento farmacológico , Transtornos dos Movimentos/genética , Proteínas do Tecido Nervoso/genética , Fenótipo , Valor Preditivo dos Testes , Proteínas de Ligação a RNA/genética , Projetos de Pesquisa , Proteínas do Complexo SMN , Atrofias Musculares Espinais da Infância/genética , Taxa de Sobrevida , Proteína 1 de Sobrevivência do Neurônio Motor , Proteína 2 de Sobrevivência do Neurônio Motor , Resultado do TratamentoRESUMO
Several psychiatric disorders are associated with white matter defects, suggesting that oligodendrocyte (OL) abnormalities underlie some aspects of these diseases. Neuregulin 1 (NRG1) and its receptor, erbB4, are genetically linked with susceptibility to schizophrenia and bipolar disorder. In vitro studies suggest that NRG1-erbB signaling is important for OL development. To test whether erbB signaling contributes to psychiatric disorders by regulating the structure or function of OLs, we analyzed transgenic mice in which erbB signaling is blocked in OLs in vivo. Here we show that loss of erbB signaling leads to changes in OL number and morphology, reduced myelin thickness, and slower conduction velocity in CNS axons. Furthermore, these transgenic mice have increased levels of dopamine receptors and transporters and behavioral alterations consistent with neuropsychiatric disorders. These results indicate that defects in white matter can cause alterations in dopaminergic function and behavior relevant to neuropsychiatric disorders.
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Dopamina/fisiologia , Receptores ErbB/fisiologia , Transtornos Mentais/etiologia , Bainha de Mielina/fisiologia , Oligodendroglia/fisiologia , Transdução de Sinais/fisiologia , Anfetamina/farmacologia , Animais , Ansiedade/etiologia , Nucleotídeo Cíclico Fosfodiesterase do Tipo 1 , Camundongos , Camundongos Transgênicos , Atividade Motora , Proteínas do Tecido Nervoso/fisiologia , Condução Nervosa , Neuregulina-1 , Diester Fosfórico Hidrolases/genética , Regiões Promotoras Genéticas , Receptor ErbB-4 , Comportamento SocialRESUMO
There are gender differences in the prevalence and severity of several human behavioral disorders, in which both obstetric complications and dysregulation of brain monoamine systems have been implicated. In animal studies, males are more susceptible than are females to lasting behavioral deficits following various perinatal insults. The current study compared monoamine levels in brain regions from adult male and female rats that had been born under various conditions-vaginal birth (control), Caesarean section (C-section), or C-section with 15 min of added anoxia (Anoxia). At adulthood, male rats born by C-section had increased dopamine (DA) levels in the nucleus accumbens and dorsal striatum, and decreased amygdalar norepinephrine (NE), compared to vaginally born males. C-sectioned female rats had increased NE levels in the thalamus in comparison to vaginally born females. The only monoamine change observed in the Anoxia groups was a decrease in nucleus accumbens NE in females. Thus addition of 15 min of anoxia to the C-section procedure reversed several of the monoamine changes produced by C-section alone. Birth group had no effect on serotonin in several brain regions in either sex. Male, but not female, rats born by C-section had decreased plasma epinephrine levels at birth and slightly increased brain lactate at 5 h after birth. Pups of both sexes in the Anoxia groups had high levels of plasma catecholamines at birth. The possible functional significance of the lasting, region-specific changes in brain DA and NE due to birth insult and possible roles of hormones at birth in producing these monoamine changes in the two sexes are discussed.
Assuntos
Traumatismos do Nascimento/metabolismo , Encéfalo/metabolismo , Catecolaminas/metabolismo , Cesárea , Hipóxia Fetal/metabolismo , Animais , Monoaminas Biogênicas/metabolismo , Traumatismos do Nascimento/etiologia , Encéfalo/patologia , Cesárea/efeitos adversos , Feminino , Hipóxia Fetal/complicações , Ácido Láctico/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Fatores Sexuais , TempoRESUMO
There is increasing evidence that proteins normally involved in the cell cycle can regulate neuronal programmed cell death (PCD). However, it remains unknown whether cell cycle markers are expressed in normal, postmitotic, postmigratory neurons undergoing PCD in vivo. We have previously shown that natural cell death occurs postnatally in dopamine neurons of the substantia nigra pars compacta (SNpc). PCD can be induced postnatally in these neurons either by intrastriatal injection of the neurotoxin 6-hydroxydopamine (6-OHDA) or by medial forebrain bundle (MFB) axotomy. At the time of induction of death in these models, these neurons are long postmitotic and postmigratory. We have studied three cell cycle markers in these models: 5-bromo-2'-deoxyuridine (BrdU) incorporation (a marker of S phase), cdc2 protein expression (a marker of G2 phase), and expression of MPM2 (a marker of M phase), an epitope phosphorylated by cdc2. We report here that postmitotic dopaminergic neurons undergoing PCD in the SNpc following 6-OHDA and axotomy lesions incorporate BrdU and overexpress cdc2, but do not express MPM2. This is the first in vivo evidence that postmitotic dopamine neurons of the SNpc undergoing apoptosis express markers for S phase and G2 phase. These results raise the possibility that cell cycle regulatory proteins may play a role in the demise of dopaminergic neurons in Parkinson's disease, in which PCD has been postulated to play a role.
Assuntos
Apoptose/fisiologia , Proteínas de Ciclo Celular/biossíntese , Dopamina/metabolismo , Neurônios/metabolismo , Substância Negra/metabolismo , Animais , Apoptose/efeitos dos fármacos , Biomarcadores/análise , Bromodesoxiuridina/metabolismo , Bromodesoxiuridina/farmacocinética , Proteína Quinase CDC2/biossíntese , Contagem de Células , Proteínas de Ciclo Celular/análise , Proteínas de Ciclo Celular/genética , Diferenciação Celular , Modelos Animais de Doenças , Fase G2/fisiologia , Mitose/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/patologia , Oxidopamina , Transtornos Parkinsonianos/induzido quimicamente , Transtornos Parkinsonianos/metabolismo , Transtornos Parkinsonianos/patologia , Fosfoproteínas/análise , Fosfoproteínas/biossíntese , Ratos , Fase S/fisiologia , Substância Negra/efeitos dos fármacos , Substância Negra/patologiaRESUMO
Birth complications involving fetal hypoxia and stress at adulthood, which are risk factors for schizophrenia, can produce alterations in subcortical dopamine (DA) function in rat models. As adults, rats born either by cesarean section (C-section) or by C-section with added global anoxia show increased stress-induced DA release from nucleus accumbens and increased amphetamine-induced locomotion, compared to vaginally born controls. Moreover, stress at adulthood interacts with these birth insults to modulate DA receptor and transporter levels. Glutamatergic transmission at the level of the nucleus accumbens, prefrontal cortex, and hippocampus are known to modulate subcortical DA activity. Thus, altered excitatory amino acid (EAA) function might contribute to the dopaminergic changes observed in rats after birth insult and/or stress at adulthood. To test this possibility, rats born vaginally, by C-section, or by C-section with 15 min of anoxia, were either repeatedly stressed (15 min of tail pinch daily for 5 days) at adulthood or received no stress, and levels of EAA receptor binding were measured by ligand autoradiography in limbic brain regions. As adults, rats born by C-section showed increases in AMPA receptor binding in nucleus accumbens shell, NMDA receptor binding in cingulate cortex, and kainate receptor binding in the hippocampal CA1 region. Anoxic rats showed increases in CA1 kainate receptor and anterior olfactory NMDA receptor binding. Stress at adulthood increased AMPA receptor binding in several regions of prefrontal cortex and reduced NMDA receptor binding in infralimbic cortex and dentate gyrus, across all birth groups. Two instances of interactions between birth insult and stress at adulthood were observed. Stress reduced cingulate cortex NMDA receptor binding and increased olfactory tubercle kainate receptor binding only in C-sectioned animals, but not in controls. The possibility that the observed EAA receptor changes contribute to dopaminergic dysfunction in these animal models is discussed, in light of known glutamate-DA interactions.