RESUMEN
OBJECTIVE: Caspase-1 plays an important functional role mediating neuronal cell death and dysfunction after experimental traumatic brain injury (TBI) in mice. Minocycline, a derivative of the antibiotic tetracycline, inhibits caspase-1 expression. This study investigates whether minocycline can ameliorate TBI-mediated injury in mice. METHODS: Brains from mice subjected to traumatic brain injury underwent immunohistochemical analyses for caspase-1, caspase-3, and a neuronal specific marker (NeuN). Minocycline- and saline-treated mice subjected to traumatic brain injury were compared with respect to neurological function, lesion volume, and interleukin-1beta production. RESULTS: Immunohistochemical analysis revealed that activated caspase-1 and caspase-3 are present in neurons 24 hours after TBI. Intraperitoneal administration of minocycline 12 hours before or 30 minutes after TBI in mice resulted in improved neurological function when compared with mice given saline control, as assessed by Rotarod performance 1 to 4 days after TBI. The lesion volume, assessed 4 days after trauma, was significantly decreased in mice treated with minocycline before or after trauma when compared with saline-treated mice. Caspase-1 activity, quantified by measuring mature interleukin-1beta production by enzyme-linked immunosorbent assay, was considerably increased in mice that underwent TBI, and this increase was significantly diminished in minocycline-treated mice. CONCLUSION: We show for the first time that caspase-1 and caspase-3 activities localize specifically within neurons after experimental brain trauma. Further, these results indicate that minocycline is an effective pharmacological agent for reducing tissue injury and neurological deficits that result from experimental TBI, likely through a caspase-1-dependent mechanism. These results provide an experimental rationale for the evaluation of minocycline in human trauma patients.
Asunto(s)
Lesiones Encefálicas/enzimología , Lesiones Encefálicas/patología , Encéfalo/patología , Caspasa 1/metabolismo , Inhibidores Enzimáticos/farmacología , Minociclina/farmacología , Sistema Nervioso/fisiopatología , Animales , Encéfalo/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Interleucina-1/antagonistas & inhibidores , Interleucina-1/biosíntesis , Ratones , Ratones Endogámicos C57BL , Sistema Nervioso/efectos de los fármacos , Neuronas/enzimologíaRESUMEN
Evidence indicates that both necrotic and apoptotic cell death contribute to tissue injury and neurological dysfunction following spinal cord injury. Caspases have been implicated as important mediators of apoptosis following acute central nervous system insults. We investigated whether caspase-1 and caspase-3 are involved in spinal cord injury-mediated cell death, and whether caspase inhibition may reduce tissue damage and improve outcome following spinal cord injury. We demonstrate a 17-fold increase in caspase-1 activity in traumatized spinal cord samples when compared with samples from sham-operated mice. Caspase-1 and caspase-3 activation were also detected by western blot following spinal cord injury, which was significantly inhibited by the broad caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. By immunofluorescence or in situ fluorogenic substrate assay, caspase-1 and caspase-3 expression were detected in neuronal and non-neuronal cells following spinal cord injury. N-Benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone treated mice, and transgenic mice expressing a caspase-1 dominant negative mutant, demonstrated a significant improvement of motor function and a reduction of lesion size compared with vehicle-treated mice. Our results demonstrate for the first time that both caspase-1 and caspase-3 are activated in neurons following spinal cord injury, and that caspase inhibition reduces post-traumatic lesion size and improves motor performance. Caspase inhibitors may be one of the agents to be used for the treatment of spinal cord injury.
Asunto(s)
Apoptosis/fisiología , Caspasa 1/metabolismo , Caspasas/metabolismo , Neuronas/metabolismo , Traumatismos de la Médula Espinal/enzimología , Clorometilcetonas de Aminoácidos/farmacología , Clorometilcetonas de Aminoácidos/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Caspasa 3 , Inhibidores de Caspasas , Activación Enzimática , Etiquetado Corte-Fin in Situ , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/fisiopatologíaRESUMEN
Increasing evidence implicates caspase-1-mediated cell death as a major mechanism of neuronal death in neurodegenerative diseases. In the present study we investigated the role of caspase-1 in neurotoxic experimental animal models of Huntington's disease (HD) by examining whether transgenic mice expressing a caspase-1 dominant-negative mutant are resistant to malonate and 3-nitropropionic acid (3-NP) neurotoxicity. Intrastriatal injection of malonate resulted in significantly smaller striatal lesions in mutant caspase-1 mice than those observed in littermate control mice. Caspase-1 was significantly activated following malonate intrastriatal administration in control mice but significantly attenuated in mutant caspase-1 mice. Systemic 3-NP treatment induced selective striatal lesions that were significantly smaller within mutant caspase-1 mice than in littermate control mice. These results provide further evidence of a functional role for caspase-1 in both malonate- and 3-NP-mediated neurotoxin models of HD.
Asunto(s)
Encéfalo/patología , Caspasa 1/genética , Caspasa 1/metabolismo , Malonatos/toxicidad , Neurotoxinas/toxicidad , Propionatos/toxicidad , Animales , Encéfalo/efectos de los fármacos , Encéfalo/enzimología , Cruzamientos Genéticos , Modelos Animales de Enfermedad , Femenino , Enfermedad de Huntington/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Neostriado/efectos de los fármacos , Neostriado/patología , Nitrocompuestos , Mutación PuntualRESUMEN
Huntington disease is an autosomal dominant neurodegenerative disease with no effective treatment. Minocycline is a tetracycline derivative with proven safety. After ischemia, minocycline inhibits caspase-1 and inducible nitric oxide synthetase upregulation, and reduces infarction. As caspase-1 and nitric oxide seem to play a role in Huntington disease, we evaluated the therapeutic efficacy of minocycline in the R6/2 mouse model of Huntington disease. We report that minocycline delays disease progression, inhibits caspase-1 and caspase-3 mRNA upregulation, and decreases inducible nitric oxide synthetase activity. In addition, effective pharmacotherapy in R6/2 mice requires caspase-1 and caspase-3 inhibition. This is the first demonstration of caspase-1 and caspase-3 transcriptional regulation in a Huntington disease model.
Asunto(s)
Caspasa 1/biosíntesis , Caspasas/biosíntesis , Enfermedad de Huntington/tratamiento farmacológico , Minociclina/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Animales , Antibacterianos/uso terapéutico , Caspasa 3 , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Activación Enzimática/efectos de los fármacos , Estudios de Evaluación como Asunto , Regulación de la Expresión Génica , Enfermedad de Huntington/mortalidad , Ratones , Ratones Transgénicos , Óxido Nítrico Sintasa/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo II , Transcripción GenéticaRESUMEN
Mutations in the copper/zinc superoxide dismutase (SOD1) gene produce an animal model of familial amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. To test a new therapeutic strategy for ALS, we examined the effect of caspase inhibition in transgenic mice expressing mutant human SOD1 with a substitution of glycine to alanine in position 93 (mSOD1(G93A)). Intracerebroventricular administration of zVAD-fmk, a broad caspase inhibitor, delays disease onset and mortality. Moreover, zVAD-fmk inhibits caspase-1 activity as well as caspase-1 and caspase-3 mRNA up-regulation, providing evidence for a non-cell-autonomous pathway regulating caspase expression. Caspases play an instrumental role in neurodegeneration in transgenic mSOD1(G93A) mice, which suggests that caspase inhibition may have a protective role in ALS.
Asunto(s)
Clorometilcetonas de Aminoácidos/farmacología , Esclerosis Amiotrófica Lateral/tratamiento farmacológico , Esclerosis Amiotrófica Lateral/enzimología , Caspasa 1/metabolismo , Caspasas/metabolismo , Neuronas Motoras/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Clorometilcetonas de Aminoácidos/administración & dosificación , Clorometilcetonas de Aminoácidos/uso terapéutico , Sustitución de Aminoácidos , Esclerosis Amiotrófica Lateral/patología , Animales , Apoptosis/efectos de los fármacos , Caspasa 1/genética , Caspasa 3 , Inhibidores de Caspasas , Caspasas/genética , Inhibidores de Cisteína Proteinasa/administración & dosificación , Inhibidores de Cisteína Proteinasa/farmacología , Inhibidores de Cisteína Proteinasa/uso terapéutico , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Activación Enzimática , Regulación Enzimológica de la Expresión Génica , Humanos , Inyecciones Intraventriculares , Interleucina-1/metabolismo , Masculino , Ratones , Ratones Transgénicos , Neuronas Motoras/enzimología , Neuronas Motoras/patología , Degeneración Nerviosa , Fármacos Neuroprotectores/administración & dosificación , Fármacos Neuroprotectores/uso terapéutico , Desempeño Psicomotor , Médula Espinal/enzimología , Superóxido Dismutasa/genética , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa-1RESUMEN
Huntington's disease is an autosomal-dominant progressive neurodegenerative disorder resulting in specific neuronal loss and dysfunction in the striatum and cortex. The disease is universally fatal, with a mean survival following onset of 15-20 years and, at present, there is no effective treatment. The mutation in patients with Huntington's disease is an expanded CAG/polyglutamine repeat in huntingtin, a protein of unknown function with a relative molecular mass of 350,000 (M(r) 350K). The length of the CAG/polyglutamine repeat is inversely correlated with the age of disease onset. The molecular pathways mediating the neuropathology of Huntington's disease are poorly understood. Transgenic mice expressing exon 1 of the human huntingtin gene with an expanded CAG/polyglutamine repeat develop a progressive syndrome with many of the characteristics of human Huntington's disease. Here we demonstrate evidence of caspase-1 activation in the brains of mice and humans with the disease. In this transgenic mouse model of Huntington's disease, expression of a dominant-negative caspase-1 mutant extends survival and delays the appearance of neuronal inclusions, neurotransmitter receptor alterations and onset of symptoms, indicating that caspase-1 is important in the pathogenesis of the disease. In addition, we demonstrate that intracerebroventricular administration of a caspase inhibitor delays disease progression and mortality in the mouse model of Huntington's disease.
Asunto(s)
Inhibidores de Caspasas , Inhibidores Enzimáticos/uso terapéutico , Enfermedad de Huntington/enzimología , Animales , Encéfalo/enzimología , Caspasa 1/genética , Progresión de la Enfermedad , Activación Enzimática , Femenino , Proteína Huntingtina , Enfermedad de Huntington/tratamiento farmacológico , Enfermedad de Huntington/genética , Enfermedad de Huntington/patología , Inyecciones Intraventriculares , Interleucina-1/metabolismo , Masculino , Ratones , Ratones Transgénicos , Mutación , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/metabolismo , Pérdida de PesoRESUMEN
Necrotic and apoptotic cell death both play a role mediating tissue injury following brain trauma. Caspase-1 (interleukin-1beta converting enzyme) is activated and oligonucleosomal DNA fragmentation is detected in traumatized brain tissue. Reduction of tissue injury and free radical production following brain trauma was achieved in a transgenic mouse expressing a dominant negative inhibitor of caspase-1 in the brain. Neuroprotection was also conferred by pharmacological inhibition of caspase-1 by intracerebroventricular administration of the selective inhibitor of caspase-1, acetyl-Tyr-Val-Ala-Asp-chloromethyl-ketone or the non-selective caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. These results indicate that inhibition of caspase-1-like caspases reduces trauma-mediated brain tissue injury. In addition, we demonstrate an in vivo functional interaction between interleukin-1beta converting enyzme-like caspases and free radical production pathways, implicating free radical production as a downstream mediator of the caspase cell death cascade.