RESUMEN
Nonketotic hyperglycinemia due to deficient glycine cleavage enzyme activity causes a severe neonatal epileptic encephalopathy. Current therapies based on mitigating glycine excess have only limited impact. An animal model with postnatal phenotyping is needed to explore new therapeutic approaches. We developed a Gldc p.Ala394Val mutant model and bred it to congenic status in two colonies on C57Bl/6J (B6) and J129X1/SvJ (J129) backgrounds. Mutant mice had reduced P-protein and enzyme activity indicating a hypomorphic mutant. Glycine levels were increased in blood and brain regions, exacerbated by dietary glycine, with higher levels in female than male J129 mice. Birth defects were more prevalent in mutant B6 than J129 mice, and hydrocephalus was more frequent in B6 (40%) compared to J129 (none). The hydrocephalus rate was increased by postnatal glycine challenge in B6 mice, more so when delivered from the first neonatal week than from the fourth. Mutant mice had reduced weight gain following weaning until the eighth postnatal week, which was exacerbated by glycine loading. The electrographic spike rate was increased in mutant mice following glycine loading, but no seizures were observed. The alpha/delta band intensity ratio was decreased in the left cortex in female J129 mice, which were less active in an open field test and explored less in a Y-maze, suggesting an encephalopathic effect. Mutant mice showed no evidence of memory dysfunction. This partial recapitulation of human symptoms and biochemistry will facilitate the evaluation of new therapeutic approaches with an early postnatal time window likely most effective.
RESUMEN
Nonketotic hyperglycinemia due to deficient glycine cleavage enzyme activity causes a severe neonatal epileptic encephalopathy. Current therapies based on mitigating glycine excess have only limited impact. An animal model with postnatal phenotyping is needed to explore new therapeutic approaches. We developed a Gldc p.Ala394Val mutant model and bred it to congenic status in 2 colonies on C57Bl/6J (B6) and J129X1/SvJ (J129) backgrounds. Mutant mice had reduced P-protein and enzyme activity indicating a hypomorphic mutant. Glycine levels were increased in blood and brain regions, exacerbated by dietary glycine, with higher levels in female than male J129 mice. Birth defects were more prevalent in mutant B6 than J129 mice, and hydrocephalus was more frequent in B6 (40%) compared to J129 (none). The hydrocephalus rate was increased by postnatal glycine challenge in B6 mice, more so when delivered from the first neonatal week than from the fourth. Mutant mice had reduced weight gain following weaning until the eighth postnatal week, which was exacerbated by glycine loading. The electrographic spike rate was increased in mutant mice following glycine loading, but no seizures were observed. The alpha/delta band intensity ratio was decreased in the left cortex in female J129 mice, which were less active in an open field test and explored less in a Y-maze, suggesting an encephalopathic effect. Mutant mice showed no evidence of memory dysfunction. This partial recapitulation of human symptoms and biochemistry will facilitate the evaluation of new therapeutic approaches with an early postnatal time window likely most effective. Take home message: A mouse model of nonketotic hyperglycinemia is described that shows postnatal abnormalities in glycine levels, neural tube defects, body weight, electroencephalographic recordings, and in activity in young mice making it amenable for the evaluation of novel treatment interventions. Author contributions: Study concept and design: JVH, MHM, NB, KNMAnimal study data: MAS, HJ, NB, MHM, JC, CBBiochemical and genetic studies: MAS, RAVH, MWFStatistical analysis: NB, JVHFirst draft writing: JVH, NB, MHMCritical rewriting: MAS, NB, MHM, TAB, JC, MWF, KNM, JVHFinal responsibility, guarantor, and communicating author: JVH. Competing interest statement: The University of Colorado (JVH, MS, KNM, HJ) has the intention to file Intellectual property protection for certain biochemical treatments of NKH. Otherwise, the authors have stated that they had no interests that might be perceived as posing a conflict or bias to this subject matter. Funding support: Financial support is acknowledged form the NKH Crusaders, Brodyn's Friends, Nora Jane Almany Foundation, the Dickens Family Foundation, the Lucas John Foundation, Les Petits Bourdons, Joseph's Fund, the Barnett Family, Maud & Vic Foundation, Lucy's BEElievers fund, Hope for NKH, Madi's Mission NKH fund, and from Dr. and Ms. Shaw, and the University of Colorado Foundation NKH research fund. The study was supported by a grant (CNS-X-19-103) from the University of Colorado School of Medicine and the Colorado Clinical Translational Science Institute, which is supported by NIH/NCATS Colorado CTSA Grant Number UL1 TR002535. Contents are the authors' sole responsibility and do not necessarily represent official NIH views. All funding sources had no role in the design or execution of the study, the interpretation of data, or the writing of the study. Ethics approval on Laboratory Animal Studies: Mouse studies were carried out with approval from the Institutional Animal Care and Use Committee of the University of Colorado Anschutz Medical Campus (IACUC# 00413). Data sharing statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.
RESUMEN
OBJECTIVE: Temporal lobe epilepsy (TLE) is a progressive disorder mediated by pathological changes in molecular cascades and hippocampal neural circuit remodeling that results in spontaneous seizures and cognitive dysfunction. Targeting these cascades may provide disease-modifying treatments for TLE patients. Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) inhibitors have emerged as potential disease-modifying therapies; a more detailed understanding of JAK/STAT participation in epileptogenic responses is required, however, to increase the therapeutic efficacy and reduce adverse effects associated with global inhibition. METHODS: We developed a mouse line in which tamoxifen treatment conditionally abolishes STAT3 signaling from forebrain excitatory neurons (nSTAT3KO). Seizure frequency (continuous in vivo electroencephalography) and memory (contextual fear conditioning and motor learning) were analyzed in wild-type and nSTAT3KO mice after intrahippocampal kainate (IHKA) injection as a model of TLE. Hippocampal RNA was obtained 24 h after IHKA and subjected to deep sequencing. RESULTS: Selective STAT3 knock-out in excitatory neurons reduced seizure progression and hippocampal memory deficits without reducing the extent of cell death or mossy fiber sprouting induced by IHKA injection. Gene expression was rescued in major networks associated with response to brain injury, neuronal plasticity, and learning and memory. We also provide the first evidence that neuronal STAT3 may directly influence brain inflammation. INTERPRETATION: Inhibiting neuronal STAT3 signaling improved outcomes in an animal model of TLE, prevented progression of seizures and cognitive co-morbidities while rescuing pathogenic changes in gene expression of major networks associated with epileptogenesis. Specifically targeting neuronal STAT3 may be an effective disease-modifying strategy for TLE. ANN NEUROL 2023;94:106-122.
Asunto(s)
Epilepsia del Lóbulo Temporal , Epilepsia , Ratones , Animales , Epilepsia del Lóbulo Temporal/inducido químicamente , Epilepsia del Lóbulo Temporal/genética , Epilepsia del Lóbulo Temporal/tratamiento farmacológico , Redes Reguladoras de Genes , Ratones Noqueados , Convulsiones , Hipocampo/patología , Neuronas/metabolismo , Cognición , Modelos Animales de EnfermedadRESUMEN
The impact of a single seizure on cognition remains controversial. We hypothesized that a single early-life seizure (sELS) on rat Postnatal Day (P) 7 would alter only hippocampus-dependent learning and memory in mature (P60) rats. The Morris water maze, the novel object and novel place recognition tasks, and contextual fear conditioning were used to assess learning and memory associated with hippocampus/prefrontal cortex, perirhinal/hippocampal cortex, and amygdala function, respectively. The elevated plus maze and open-field test were used to assess anxiety associated with the septum. We report that sELS impaired hippocampus-dependent short-term memory, but not spatial learning or recall. sELS did not disrupt performance in the novel object and novel place recognition tasks. Contextual fear conditioning performance suggested intact amydgala function. sELS did not change anxiety levels as measured by the elevated plus maze or open-field test. Our data suggest that the long-term cognitive impact of sELS is limited largely to the hippocampus/prefrontal cortex.
Asunto(s)
Trastornos de la Memoria/etiología , Memoria a Corto Plazo/fisiología , Reconocimiento en Psicología/fisiología , Convulsiones/complicaciones , Percepción Espacial/fisiología , Análisis de Varianza , Animales , Animales Recién Nacidos , Ansiedad/fisiopatología , Condicionamiento Clásico/efectos de los fármacos , Condicionamiento Clásico/fisiología , Modelos Animales de Enfermedad , Conducta Exploratoria/fisiología , Conducta Exploratoria/efectos de la radiación , Miedo , Femenino , Ácido Kaínico , Masculino , Aprendizaje por Laberinto/fisiología , Pruebas Neuropsicológicas , Embarazo , Ratas , Convulsiones/inducido químicamenteRESUMEN
OBJECTIVE: The contribution of seizures to cognitive changes remains controversial. We tested the hypothesis that a single episode of neonatal seizures (sNS) on rat postnatal day (P) 7 permanently impairs hippocampal-dependent function in mature (P60) rats because of long-lasting changes at the synaptic level. METHODS: sNS was induced with subcutaneously injected kainate on P7. Learning, memory, mossy fiber sprouting, spine density, hippocampal synaptic plasticity, and glutamate receptor expression and subcellular distribution were measured at P60. RESULTS: sNS selectively impaired working memory in a hippocampal-dependent radial arm water-maze task without inducing mossy fiber sprouting or altering spine density. sNS impaired CA1 hippocampal long-term potentiation and enhanced long-term depression. Subcellular fractionation and cross-linking, used to determine whether glutamate receptor trafficking underlies the alterations of memory and synaptic plasticity, demonstrated that sNS induced a selective reduction in the membrane pool of glutamate receptor 1 subunits. sNS induced a decrease in the total amount of N-methyl-D-aspartate receptor 2A and an increase in the primary subsynaptic scaffold, PSD-95. INTERPRETATION: These molecular consequences are consistent with the alterations in plasticity and memory caused by sNS at the synaptic level. Our data demonstrate the cognitive impact of sNS and associate memory deficits with specific alterations in glutamatergic synaptic function.
Asunto(s)
Ácido Glutámico/fisiología , Convulsiones/patología , Sinapsis/patología , Animales , Animales Recién Nacidos , Western Blotting , Reactivos de Enlaces Cruzados , Dendritas/efectos de los fármacos , Dendritas/ultraestructura , Homólogo 4 de la Proteína Discs Large , Electrofisiología , Agonistas de Aminoácidos Excitadores , Femenino , Hipocampo/patología , Inmunohistoquímica , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ácido Kaínico , Aprendizaje por Laberinto/fisiología , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Memoria/fisiología , Recuerdo Mental/fisiología , Fibras Musgosas del Hipocampo/patología , Plasticidad Neuronal/fisiología , Embarazo , Ratas , Ratas Sprague-Dawley , Receptores de N-Metil-D-Aspartato/genética , Convulsiones/inducido químicamente , Convulsiones/psicología , Fracciones Subcelulares/patologíaRESUMEN
Experimental, clinical, and epidemiologic studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) are beneficial in Alzheimer's disease and other neuroinflammatory processes. One possible mechanism is an interaction with peroxisome proliferator-activated receptors (PPARs). We examined the effect of a specific PPARgamma agonist, rosiglitazone, on contextual fear conditioning in aged rats. Male rats (20-months-old) were administered rosiglitazone in the diet for 2 months prior to behavioral testing. Young control and aged rats fed rosiglitazone froze significantly more than did the aged control rats in a hippocampal-dependent fear conditioning task. Rosiglitazone had no effect hippocampal interleukin-1beta levels, markers of oxidative damage, and NMDA receptor expression. Therefore, activation of PPARgamma prevented age-related deficits in hippocampal function.
Asunto(s)
Envejecimiento/efectos de los fármacos , Condicionamiento Psicológico/efectos de los fármacos , Miedo/efectos de los fármacos , Tiazolidinedionas/farmacología , Envejecimiento/fisiología , Envejecimiento/psicología , Animales , Condicionamiento Psicológico/fisiología , Miedo/fisiología , Miedo/psicología , Masculino , Ratas , Ratas Endogámicas F344 , RosiglitazonaRESUMEN
Inflammatory processes in the central nervous system are thought to contribute to Alzheimer's disease (AD). Chronic administration of nonsteroidal anti-inflammatory drugs (NSAIDs) decreases the incidence of Alzheimer's disease. There are very few studies, however, on the cognitive impact of chronic NSAID administration. The N-methyl-d-aspartate (NMDA) receptor is implicated in learning and memory, and age-related decreases in the NMDA NR2B subunit correlate with memory deficits. Sulindac, an NSAID that is a nonselective cyclooxygenase (COX) inhibitor was chronically administered to aged Fischer 344 rats for 2 months. Sulindac, but not its non-COX active metabolite, attenuated age-related deficits in learning and memory as assessed in the radial arm water maze and contextual fear conditioning tasks. Sulindac treatment also attenuated an age-related decrease in the NR1 and NR2B NMDA receptor subunits and prevented an age-related increase in the pro-inflammatory cytokine, interleukin 1beta (IL-1beta), in the hippocampus. These findings support the inflammation hypothesis of aging and have important implications for potential cognitive enhancing effects of NSAIDs in the elderly.
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Envejecimiento/efectos de los fármacos , Aldehído Deshidrogenasa/genética , Encefalitis/tratamiento farmacológico , Trastornos de la Memoria/tratamiento farmacológico , Receptores de N-Metil-D-Aspartato/efectos de los fármacos , Sulindac/farmacología , Envejecimiento/metabolismo , Aldehído Deshidrogenasa Mitocondrial , Animales , Antiinflamatorios no Esteroideos/farmacología , Antiinflamatorios no Esteroideos/uso terapéutico , Condicionamiento Psicológico/efectos de los fármacos , Condicionamiento Psicológico/fisiología , Modelos Animales de Enfermedad , Regulación hacia Abajo/efectos de los fármacos , Regulación hacia Abajo/fisiología , Encefalitis/fisiopatología , Encefalitis/prevención & control , Interleucina-1/metabolismo , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Trastornos de la Memoria/metabolismo , Trastornos de la Memoria/fisiopatología , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Nootrópicos/farmacología , Nootrópicos/uso terapéutico , Ratas , Ratas Endogámicas F344 , Receptores de N-Metil-D-Aspartato/metabolismo , Sulindac/uso terapéutico , Resultado del Tratamiento , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/fisiologíaRESUMEN
Alzheimer's disease and normal aging may impair retrograde transport of nerve growth factor (NGF) from cortical areas to basal forebrain cholinergic neurons. We demonstrate a relationship between performance in a spatial reference memory task and NGF distribution in the aged rat brain. In addition, exogenous NGF restored endogenous NGF distribution in cognitively impaired aged rats. These data suggest that NGF administration restores utilization of endogenous growth factor in the brain of cognitively impaired aged rats.
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Envejecimiento/efectos de los fármacos , Encéfalo/efectos de los fármacos , Trastornos del Conocimiento/tratamiento farmacológico , Factor de Crecimiento Nervioso/metabolismo , Factor de Crecimiento Nervioso/uso terapéutico , Envejecimiento/metabolismo , Animales , Encéfalo/metabolismo , Trastornos del Conocimiento/metabolismo , Masculino , Factor de Crecimiento Nervioso/farmacología , Ratas , Ratas Endogámicas F344RESUMEN
The hippocampus is critical for spatial memory formation in rodents. Calcium currents through L-type voltage-sensitive calcium channels (L-VSCCs) are increased in CA1 neurons of the hippocampus of aged rats. We have recently shown that expression of the calcium conducting L-VSCC subunit alpha(1D) (Ca(v)1.3) is selectively increased in area CA1 of aged rats. We and others have speculated that excessive Ca(2+) influx through L-VSCC may be detrimental to memory formation. Therefore, we investigated the relationship between age-related working memory decline and alpha(1D) protein expression in the hippocampus. In addition, we studied the effects of chronic treatment with the L-VSCC antagonist nimodipine (NIM) on age-related working memory deficits and alpha(1D) expression in the hippocampus. Here we report that age-related increases in alpha(1D) expression in area CA1 correlate with working memory impairment in Fischer 344 rats. Furthermore, we demonstrate that chronic NIM treatment ameliorates age-related working memory deficits and reduces expression of alpha(1D) protein in the hippocampus. The present results suggest that L-VSCCs participate in processes underlying memory formation and that increases in L-VSCC protein and currents observed with aging may play a role in age-related memory decline. Furthermore, the amelioration in age-related memory decline produced by NIM treatment may be mediated, at least in part, by reductions in the abnormally high levels of alpha(1D) protein in the aged hippocampus. These findings may have implications for patients with Alzheimer's disease, who show increased L-VSCC protein expression in the hippocampus, and for patients receiving chronic treatment with L-VSCC antagonists.
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Envejecimiento/metabolismo , Bloqueadores de los Canales de Calcio/farmacología , Canales de Calcio Tipo L/metabolismo , Hipocampo/metabolismo , Trastornos de la Memoria/metabolismo , Nimodipina/farmacología , Animales , Canales de Calcio , Canales de Calcio Tipo L/efectos de los fármacos , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Hipocampo/efectos de los fármacos , Hipocampo/fisiopatología , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Trastornos de la Memoria/tratamiento farmacológico , Trastornos de la Memoria/fisiopatología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Ratas , Ratas Endogámicas F344 , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Receptores de N-Metil-D-Aspartato/efectos de los fármacos , Receptores de N-Metil-D-Aspartato/metabolismo , Sinapsis/efectos de los fármacos , Sinapsis/metabolismo , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiologíaRESUMEN
Antioxidants and diets supplemented with foods high in oxygen radical absorbance capacity (ORAC) reverse age-related decreases in cerebellar beta-adrenergic receptor function. We examined whether this effect was related to the antioxidant capacity of the food supplement and whether an antioxidant-rich diet reduced the levels of proinflammatory cytokines in the cerebellum. Aged male Fischer 344 rats were given apple (5 mg dry weight), spirulina (5 mg), or cucumber (5 mg) either in 0.5 ml water by oral gavage or supplied in the rat chow daily for 14 d. Electrophysiologic techniques revealed a significant decrease in beta-adrenergic receptor function in aged control rats. Spirulina reversed this effect. Apple (a food with intermediate ORAC) had an intermediate effect on cerebellar beta-adrenergic receptor physiology, and cucumber (low ORAC) had no effect, indicating that the reversal of beta-adrenergic receptor function decreases might be related to the ORAC dose. The mRNA of the proinflammatory cytokines tumor necrosis factor-alpha (TNFalpha) and TNFbeta was also examined. RNase protection assays revealed increased levels of these cytokines in the aged cerebellum. Spirulina and apple significantly downregulated this age-related increase in proinflammatory cytokines, whereas cucumber had no effect, suggesting that one mechanism by which these diets work is by modulation of an age-related increase in inflammatory responses. Malondialdehyde (MDA) was measured as a marker of oxidative damage. Apple and spirulina but not cucumber decreased MDA levels in the aged rats. In summary, the improved beta-adrenergic receptor function in aged rats induced by diets rich in antioxidants is related to the ORAC dose, and these diets reduce proinflammatory cytokine levels.
Asunto(s)
Envejecimiento/efectos de los fármacos , Antioxidantes/farmacología , Cerebelo/efectos de los fármacos , Citocinas/metabolismo , Suplementos Dietéticos , Receptores Adrenérgicos beta/metabolismo , Envejecimiento/sangre , Envejecimiento/fisiología , Animales , Proteínas Bacterianas , Cerebelo/metabolismo , Cucumis sativus , Citocinas/genética , Electrofisiología , Inflamación/dietoterapia , Inflamación/metabolismo , Iontoforesis , Masculino , Malondialdehído/sangre , Malus , Modelos Animales , Inhibición Neural/efectos de los fármacos , Norepinefrina/sangre , Fitoterapia , Células de Purkinje/efectos de los fármacos , Células de Purkinje/fisiología , ARN Mensajero/metabolismo , Ratas , Ratas Endogámicas F344 , Receptores Adrenérgicos beta/efectos de los fármacos , Spirulina , Ácido gamma-Aminobutírico/administración & dosificaciónRESUMEN
Aged rats are known to have deficits in spatial learning behavior in the Morris water maze. We have found that aged rats also have deficits in NR2B protein expression and that the protein expression deficit is correlated with their performance in the Morris water maze. To test whether this NR2B deficit was sufficient to account for the behavioral deficit, we used antisense oligonucleotides to specifically knock down NR2B subunit expression in the hippocampus of young rats. NR2B antisense treatment diminished NMDA receptor responses, abolished NMDA-dependent long-term potentiation (LTP), and impaired spatial learning. These data demonstrate the important role of NR2B in LTP and learning and memory and suggest a role for reduced NR2B expression in age-related cognitive decline.