Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 89
Filtrar
1.
Pharmacol Res Perspect ; 12(2): e1181, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38429943

RESUMEN

Our laboratory has shown that calpain-2 activation in the brain following acute injury is directly related to neuronal damage and the long-term functional consequences of the injury, while calpain-1 activation is generally neuroprotective and calpain-1 deletion exacerbates neuronal injury. We have also shown that a relatively selective calpain-2 inhibitor, referred to as C2I, enhanced long-term potentiation and learning and memory, and provided neuroprotection in the controlled cortical impact (CCI) model of traumatic brain injury (TBI) in mice. Using molecular dynamic simulation and Site Identification by Ligand Competitive Saturation (SILCS) software, we generated about 130 analogs of C2I and tested them in a number of in vitro and in vivo assays. These led to the identification of two interesting compounds, NA-112 and NA-184. Further analyses indicated that NA-184, (S)-2-(3-benzylureido)-N-((R,S)-1-((3-chloro-2-methoxybenzyl)amino)-1,2-dioxopentan-3-yl)-4-methylpentanamide, selectively and dose-dependent inhibited calpain-2 activity without evident inhibition of calpain-1 at the tested concentrations in mouse brain tissues and human cell lines. Like NA-112, NA-184 inhibited TBI-induced calpain-2 activation and cell death in mice and rats, both male and females. Pharmacokinetic and pharmacodynamic analyses indicated that NA-184 exhibited properties, including stability in plasma and liver and blood-brain barrier permeability, that make it a good clinical candidate for the treatment of TBI.


Asunto(s)
Lesiones Traumáticas del Encéfalo , Lesiones Encefálicas , Fármacos Neuroprotectores , Animales , Humanos , Masculino , Ratones , Ratas , Encéfalo/metabolismo , Lesiones Encefálicas/tratamiento farmacológico , Lesiones Traumáticas del Encéfalo/tratamiento farmacológico , Calpaína/antagonistas & inhibidores , Neuroprotección , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/farmacología
2.
Front Mol Neurosci ; 17: 1337850, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38361744

RESUMEN

In 1984, Gary Lynch and Michel Baudry published in Science a novel biochemical hypothesis for learning and memory, in which they postulated that the calcium-dependent protease, calpain, played a critical role in regulating synaptic properties and the distribution of glutamate receptors, thereby participating in memory formation in hippocampus. Over the following 40 years, much work has been done to refine this hypothesis and to provide convincing arguments supporting what was viewed at the time as a simplistic view of synaptic biochemistry. We have now demonstrated that the two major calpain isoforms in the brain, calpain-1 and calpain-2, execute opposite functions in both synaptic plasticity/learning and memory and in neuroprotection/neurodegeneration. Thus, calpain-1 activation is required for triggering long-term potentiation (LTP) of synaptic transmission and learning of episodic memory, while calpain-2 activation limits the magnitude of LTP and the extent of learning. On the other hand, calpain-1 is neuroprotective while calpain-2 is neurodegenerative, and its prolonged activation following various types of brain insults leads to neurodegeneration. The signaling pathways responsible for these functions have been identified and involve local protein synthesis, cytoskeletal regulation, and regulation of glutamate receptors. Human families with mutations in calpain-1 have been reported to have impairment in motor and cognitive functions. Selective calpain-2 inhibitors have been synthesized and clinical studies to test their potential use to treat disorders associated with acute neuronal damage, such as traumatic brain injury, are being planned. This review will illustrate the long and difficult journey to validate a bold hypothesis.

3.
Sci Rep ; 13(1): 18647, 2023 10 30.
Artículo en Inglés | MEDLINE | ID: mdl-37903805

RESUMEN

Angelman syndrome (AS) is a rare neurogenetic disorder caused by UBE3A deficiency and characterized by severe developmental delay, cognitive impairment, and motor dysfunction. In the present study, we performed RNA-seq on hippocampal samples from both wildtype (WT) and AS male mice, with or without contextual fear memory recall. There were 281 recall-associated differentially expressed genes (DEGs) in WT mice and 268 DEGs in AS mice, with 129 shared by the two genotypes. Gene ontology analysis showed that extracellular matrix and stimulation-induced response genes were prominently enriched in recall-associated DEGs in WT mice, while nuclear acid metabolism and tissue development genes were highly enriched in those from AS mice. Further analyses showed that the 129 shared DEGs belonged to nuclear acid metabolism and tissue development genes. Unique recall DEGs in WT mice were enriched in biological processes critical for synaptic plasticity and learning and memory, including the extracellular matrix network clustered around fibronectin 1 and collagens. In contrast, AS-specific DEGs were not enriched in any known pathways. These results suggest that memory recall in AS mice, while altering the transcriptome, fails to recruit memory-associated transcriptional programs, which could be responsible for the memory impairment in AS mice.


Asunto(s)
Síndrome de Angelman , Ratones , Masculino , Animales , Síndrome de Angelman/genética , Trastornos de la Memoria/metabolismo , Hipocampo/metabolismo , Miedo , Memoria
4.
Neurotherapeutics ; 20(6): 1592-1602, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37474874

RESUMEN

While calpains have long been implicated in neurodegeneration, no calpain inhibitor has been developed for the treatment of neurodegeneration. This is partly due to the lack of understanding of the specific functions of most of the 15 members of the calpain family. Work from our laboratory over the last 5-10 years has revealed that calpain-1 and calpain-2, two of the major calpain isoforms in the brain, play opposite roles in both synaptic plasticity/learning and memory and neuroprotection/neurodegeneration. Thus, calpain-1 activation is required for triggering certain forms of synaptic plasticity and for learning some types of information and is neuroprotective. In contrast, calpain-2 activation limits the extent of synaptic plasticity and of learning and is neurodegenerative. These results have been validated with the use of calpain-1 knock-out mice and mice with a selective calpain-2 deletion in excitatory neurons of the forebrain. Through a medicinal chemistry campaign, we have identified a number of selective calpain-2 inhibitors and shown that these inhibitors do facilitate learning of certain tasks and are neuroprotective in a number of animal models of acute neurodegeneration. One of these inhibitors, NA-184, is currently being developed for the treatment of traumatic brain injury, and clinical trials are being planned.


Asunto(s)
Lesiones Traumáticas del Encéfalo , Calpaína , Ratones , Animales , Calpaína/metabolismo , Lesiones Traumáticas del Encéfalo/tratamiento farmacológico , Plasticidad Neuronal/fisiología , Neuronas/metabolismo , Encéfalo/metabolismo
5.
Exp Neurol ; 363: 114358, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36849003

RESUMEN

Angelman Syndrome (AS) is a neurodevelopmental disorder caused by deficiency of the maternally expressed UBE3A gene. The UBE3A proteins functions both as an E3 ligase in the ubiquitin-proteasome system (UPS), and as a transcriptional co-activator for steroid hormone receptors. Here we investigated the effects of UBE3A deficiency on autophagy in the cerebellum of AS mice and in COS1 cells. Numbers and size of LC3- and LAMP2-immunopositive puncta were increased in cerebellar Purkinje cells of AS mice, as compared to wildtype mice. Western blot analysis showed an increase in the conversion of LC3I to LC3II in AS mice, as expected from increased autophagy. Levels of active AMPK and of one of its substrates, ULK1, a factor involved in autophagy initiation, were also increased. Colocalization of LC3 with LAMP2 was increased and p62 levels were decreased, indicating an increase in autophagy flux. UBE3A deficiency was also associated with reduced levels of phosphorylated p53 in the cytosol and increased levels in nuclei, which favors autophagy induction. UBE3A siRNA knockdown in COS-1 cells resulted in increased size and intensity of LC3-immunopositive puncta and increased the LC3 II/I ratio, as compared to control siRNA-treated cells, confirming the results found in the cerebellum of AS mice. These results indicate that UBE3A deficiency enhances autophagic activity through activation of the AMPK-ULK1 pathway and alterations in p53.


Asunto(s)
Proteínas Quinasas Activadas por AMP , Proteína p53 Supresora de Tumor , Ratones , Animales , Proteínas Quinasas Activadas por AMP/metabolismo , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Autofagia , Cerebelo/metabolismo , ARN Interferente Pequeño/farmacología , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo
6.
Front Psychiatry ; 13: 984677, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36405921

RESUMEN

Background: Physical activity (PA) is considered a favorable preventive intervention for postpartum depression (PPD), but evidence defining a corresponding dose-response relationship is lacking. This meta-analysis was conducted to assess the protective effects of PA on PPD and define a potential dose-response relationship between them. Methods: PubMed, Medline, Embase, and Web of Science were searched from 1968 to May 2022. Only randomized control trials (RCTs) and prospective studies were considered, and the PICOS tool was used to identify eligible articles based on the inclusion and exclusion criteria. Effect-size estimates were unified as odds ratio (OR) and 95% confidence interval (CI). We calculated the ORs and their 95% CI for studies that did not report them using the Practical Meta-Analysis Effect Size Calculator. Results: A total of 23 studies were eligible, including 14 RCTs and 9 prospective cohort studies. The overall analysis showed a statistically significant positive association between PA and PPD prevention (adjusted OR = 0.73; 95% CI: 0.61-0.87; P < 0.001). Subgroup analyses indicated that studies conducted in Europe demonstrated a significant correlation between PA and reduced PPD risk (adjusted OR = 0.85, 95% CI: 0.76-0.95, P = 0.004). Concerning PA type, sports activity was associated with relieving PPD symptoms (adjusted OR = 0.89, 95% CI: 0.78 to 1.00, P < 0.001), while work (adjusted OR = 1.05, 95% CI: 0.37-2.97, P = 0.065) and household activities (adjusted OR = 1.16, 95% CI: 0.89-1.52, P = 0.986) contributed to a greater risk of PPD. Our dose-response analysis revealed a reverse J-shaped trend between ascending PA duration and PPD incidence. Conclusion: This meta-analysis identified PA as a potential intervention to reduce the risk of PPD. The dose-response analysis revealed that at least 90 min of PA per week could efficiently decrease the risk of PPD. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022335731.

7.
Neural Plast ; 2022: 3923384, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36237484

RESUMEN

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe developmental delay, motor impairment, language and cognition deficits, and often with increased seizure activity. AS is caused by deficiency of UBE3A, which is both an E3 ligase and a cofactor for transcriptional regulation. We previously showed that the small conductance potassium channel protein SK2 is a UBE3A substrate, and that increased synaptic SK2 levels contribute to impairments in synaptic plasticity and fear-conditioning memory, as inhibition of SK2 channels significantly improved both synaptic plasticity and fear memory in male AS mice. In the present study, we investigated UBE3a-mediated regulation of synaptic plasticity and fear-conditioning in female AS mice. Results from both western blot and immunofluorescence analyses showed that synaptic SK2 levels were significantly increased in hippocampus of female AS mice, as compared to wild-type (WT) littermates. Like in male AS mice, long-term potentiation (LTP) was significantly reduced while long-term depression (LTD) was enhanced at hippocampal CA3-CA1 synapses of female AS mice, as compared to female WT mice. Both alterations were significantly reduced by treatment with the SK2 inhibitor, apamin. The shunting effect of SK2 channels on NMDA receptor was significantly larger in female AS mice as compared to female WT mice. Female AS mice also showed impairment in both contextual and tone memory recall, and this impairment was significantly reduced by apamin treatment. Our results indicate that like male AS mice, female AS mice showed significant impairment in both synaptic plasticity and fear-conditioning memory due to increased levels of synaptic SK2 channels. Any therapeutic strategy to reduce SK2-mediated inhibition of NMDAR should be beneficial to both male and female patients.


Asunto(s)
Síndrome de Angelman , Síndrome de Angelman/metabolismo , Animales , Apamina , Modelos Animales de Enfermedad , Femenino , Hipocampo/metabolismo , Potenciación a Largo Plazo/fisiología , Masculino , Trastornos de la Memoria/metabolismo , Ratones , Ratones Endogámicos C57BL , Plasticidad Neuronal/fisiología , Receptores de N-Metil-D-Aspartato/metabolismo , Canales de Potasio de Pequeña Conductancia Activados por el Calcio , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina-Proteína Ligasas/farmacología
8.
EMBO J ; 41(5): e108119, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-35099830

RESUMEN

Lysosomes function not only as degradatory compartments but also as dynamic intracellular calcium ion stores. The transient receptor potential mucolipin 1 (TRPML1) channel mediates lysosomal Ca2+ release, thereby participating in multiple cellular functions. The pentameric Ragulator complex, which plays a critical role in the activation of mTORC1, is also involved in lysosomal trafficking and is anchored to lysosomes through its LAMTOR1 subunit. Here, we report that the Ragulator restricts lysosomal trafficking in dendrites of hippocampal neurons via LAMTOR1-mediated tonic inhibition of TRPML1 activity, independently of mTORC1. LAMTOR1 directly interacts with TRPML1 through its N-terminal domain. Eliminating this inhibition in hippocampal neurons by LAMTOR1 deletion or by disrupting LAMTOR1-TRPML1 binding increases TRPML1-mediated Ca2+ release and facilitates dendritic lysosomal trafficking powered by dynein. LAMTOR1 deletion in the hippocampal CA1 region of adult mice results in alterations in synaptic plasticity, and in impaired object-recognition memory and contextual fear conditioning, due to TRPML1 activation. Mechanistically, changes in synaptic plasticity are associated with increased GluA1 dephosphorylation by calcineurin and lysosomal degradation. Thus, LAMTOR1-mediated inhibition of TRPML1 is critical for regulating dendritic lysosomal motility, synaptic plasticity, and learning.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Calcio/metabolismo , Hipocampo/metabolismo , Lisosomas/metabolismo , Neuronas/metabolismo , Canales de Potencial de Receptor Transitorio/metabolismo , Animales , Línea Celular Tumoral , Células Cultivadas , Células HeLa , Humanos , Ratones , Plasticidad Neuronal/fisiología
9.
J Neurotrauma ; 38(22): 3077-3085, 2021 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-34498916

RESUMEN

Biomarkers play an increasing role in medicinal biology. They are used for diagnosis, management, drug target identification, drug responses, and disease prognosis. We have discovered that calpain-1 and calpain-2 play opposite functions in neurodegeneration, with calpain-1 activation being neuroprotective, while prolonged calpain-2 activation is neurodegenerative. This notion has been validated in several mouse models of acute neuronal injury, in particular in mouse models of traumatic brain injury (TBI) and repeated concussions. We have identified a selective substrate of calpain-2, the tyrosine phosphatase, PTPN13, which is cleaved in brain after TBI. One of the fragments generated by calpain-2, referred to as P13BP, is also found in the blood after TBI both in mice and humans. In humans, P13BP blood levels are significantly correlated with the severity of TBI, as measured by Glasgow Coma Scale scores and loss of consciousness. The results indicate that P13BP represents a novel blood biomarker for TBI.


Asunto(s)
Biomarcadores/sangre , Lesiones Traumáticas del Encéfalo/sangre , Proteína Tirosina Fosfatasa no Receptora Tipo 13/metabolismo , Animales , Calpaína/metabolismo , Modelos Animales de Enfermedad , Femenino , Escala de Coma de Glasgow , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratas , Ratas Sprague-Dawley
10.
Front Mol Biosci ; 8: 685938, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34212005

RESUMEN

While calpains have been implicated in neurogenesis for a long time, there is still little information regarding the specific contributions of various isoforms in this process. We took advantage of the availability of mutant mice with complete deletion of calpain-1 to analyze its contribution to neurogenesis. We first used the incorporation of BrdU in newly-generated cells in the subgranular zone of the dentate gyrus to determine the role of calpain-1 deletion in neuronal proliferation. Our results showed that the lack of calpain-1 decreased the rate of cell proliferation in adult hippocampus. As previously shown, it also decreased the long-term survival of newly-generated neurons. We also used data from previously reported RNA and miRNA sequencing analyses to identify differentially expressed genes in brain of calpain-1 knock-out mice related to cell division, cell migration, cell proliferation and cell survival. A number of differentially expressed genes were identified, which could play a significant role in the changes in neurogenesis in calpain-1 knock out mice. The results provide new information regarding the role of calpain-1 in neurogenesis and have implications for better understanding the pathologies associated with calpain-1 mutations in humans.

11.
BBA Adv ; 12021.
Artículo en Inglés | MEDLINE | ID: mdl-34286311

RESUMEN

Calpain-1 knock-out (KO) mice exhibit enhanced susceptibility to neurodegeneration due to the lack of the neuroprotective function of calpain-1. Dicer has been shown to play a fundamental role in the biogenesis of most miRNAs. Here, we identified 45 differentially expressed miRNAs (DE miRNAs) in the brain of calpain-1 KO mice, as compared to wild-type mice. In particular, among all the DE miRNAs, 7 neurodegeneration-related miRNAs were found to be down-regulated in calpain-1 KO mice. We also found that Dicer is cleaved by calpain-1 in mouse brain, which generates an active fragment of Dicer with RNAse III activity and increases miRNA formation. Levels of active Dicer were reduced in brain homogenates from calpain-1 KO mice and incubation with calpain-1 and calcium restored Dicer activity and miRNA expression. Our results indicate that calpain-1 deletion results in decreased levels of active Dicer and changes in neurodegenerative-related miRNAs. These findings could account for some of the pathological changes found in brain of various mammals, including humans, with calpain-1 mutations or down-regulation.

12.
Neurobiol Dis ; 147: 105149, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-33132163

RESUMEN

Calpain has been proposed to play a critical role in the development of epilepsy. Here we used conditional calpain-2 knock-out (C2CKO) mice in a C57/Bl6 background and a selective calpain-2 inhibitor to analyze the role of calpain-2 in epilepsy. Neurodegeneration was evident in various hippocampal subfields, in particular in mossy cells in the hilus of the dentate gyrus (DG) in C57/Bl6 mice 7 days after kainic acid (KA)-induced seizures. Calpain-2 activation was still observed in mossy cells 7 days after seizures. Calpain activation, astroglial and microglial activation, neurodegeneration, and cognitive impairment were absent in C2CKO mice and in C57/Bl6 mice treated with a selective calpain-2 inhibitor for 7 days after seizure initiation. Levels of the potassium chloride cotransporter 2 (KCC2) were decreased in mossy cells 7 days after seizures and this decrease was prevented by calpain-2 deletion or selective inhibition. Our results indicate that prolonged calpain-2 activation plays a critical role in neuropathology following seizures. A selective calpain-2 inhibitor could represent a therapeutic treatment for seizure-induced neuropathology.


Asunto(s)
Calpaína/metabolismo , Epilepsia/metabolismo , Hipocampo/metabolismo , Hipocampo/patología , Animales , Epilepsia/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Convulsiones/metabolismo , Convulsiones/patología
13.
Cells ; 9(12)2020 12 16.
Artículo en Inglés | MEDLINE | ID: mdl-33339205

RESUMEN

Calpains are a family of soluble calcium-dependent proteases that are involved in multiple regulatory pathways. Our laboratory has focused on the understanding of the functions of two ubiquitous calpain isoforms, calpain-1 and calpain-2, in the brain. Results obtained over the last 30 years led to the remarkable conclusion that these two calpain isoforms exhibit opposite functions in the brain. Calpain-1 activation is required for certain forms of synaptic plasticity and corresponding types of learning and memory, while calpain-2 activation limits the extent of plasticity and learning. Calpain-1 is neuroprotective both during postnatal development and in adulthood, while calpain-2 is neurodegenerative. Several key protein targets participating in these opposite functions have been identified and linked to known pathways involved in synaptic plasticity and neuroprotection/neurodegeneration. We have proposed the hypothesis that the existence of different PDZ (PSD-95, DLG and ZO-1) binding domains in the C-terminal of calpain-1 and calpain-2 is responsible for their association with different signaling pathways and thereby their different functions. Results with calpain-2 knock-out mice or with mice treated with a selective calpain-2 inhibitor indicate that calpain-2 is a potential therapeutic target in various forms of neurodegeneration, including traumatic brain injury and repeated concussions.


Asunto(s)
Encéfalo/patología , Calpaína/metabolismo , Neuronas/enzimología , Neuronas/patología , Animales , Muerte Celular , Humanos , Plasticidad Neuronal , Neuroprotección
14.
Sci Adv ; 6(27)2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32937436

RESUMEN

Repeated concussion represents a serious health problem as it can result in various brain pathologies, ranging from minor focal tissue injury to severe chronic traumatic encephalopathy. The calcium-dependent protease, calpain, participates in the development of neurodegeneration following concussion, but there is no information regarding the relative contribution of calpain-1 and calpain-2, the major calpain isoforms in the brain. We used a mouse model of repeated concussions, which reproduces most of the behavioral and neuropathological features of the human condition, to address this issue. Deletion of calpain-2 or treatment with a selective calpain-2 inhibitor for 2 weeks prevented most of these neuropathological features. Changes in TAR DNA binding protein 43 (TDP-43) subcellular localization similar to those found in human amyotrophic lateral sclerosis and frontotemporal dementia were also prevented by deletion of calpain-2 or treatment with calpain-2 inhibitor. Our results indicate that a selective calpain-2 inhibitor represents a therapeutic approach for concussion.


Asunto(s)
Conmoción Encefálica , Calpaína , Esclerosis Amiotrófica Lateral , Animales , Encéfalo/fisiopatología , Conmoción Encefálica/complicaciones , Conmoción Encefálica/tratamiento farmacológico , Calpaína/antagonistas & inhibidores , Calpaína/genética , Demencia Frontotemporal , Ratones
15.
Biochim Biophys Acta Mol Cell Res ; 1867(12): 118834, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-32860835

RESUMEN

Small conductance calcium-activated potassium channels (SKs) are solely activated by intracellular Ca2+ and their activation leads to potassium efflux, thereby repolarizing/hyperpolarizing membrane potential. Thus, these channels play a critical role in synaptic transmission, and consequently in information transmission along the neuronal circuits expressing them. SKs are widely but not homogeneously distributed in the central nervous system (CNS). Activation of SKs requires submicromolar cytoplasmic Ca2+ concentrations, which are reached following either Ca2+ release from intracellular Ca2+ stores or influx through Ca2+ permeable membrane channels. Both Ca2+ sensitivity and synaptic levels of SKs are regulated by protein kinases and phosphatases, and degradation pathways. SKs in turn control the activity of multiple Ca2+ channels. They are therefore critically involved in coordinating diverse Ca2+ signaling pathways and controlling Ca2+ signal amplitude and duration. This review highlights recent advances in our understanding of the regulation of SK2 channels and of their roles in normal brain functions, including synaptic plasticity, learning and memory, and rhythmic activities. It will also discuss how alterations in their expression and regulation might contribute to various brain disorders such as Angelman Syndrome, Alzheimer's disease and Parkinson's disease.


Asunto(s)
Plasticidad Neuronal/genética , Neuronas/metabolismo , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/genética , Transmisión Sináptica/genética , Calcio/metabolismo , Hipocampo/metabolismo , Humanos , Transducción de Señal/genética , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/metabolismo
16.
Sci Rep ; 10(1): 9824, 2020 06 17.
Artículo en Inglés | MEDLINE | ID: mdl-32555345

RESUMEN

The ubiquitin ligase, Ube3a, plays important roles in brain development and functions, since its deficiency results in Angelman Syndrome (AS) while its over-expression increases the risk for autism. We previously showed that the lack of Ube3a-mediated ubiquitination of the Ca2+-activated small conductance potassium channel, SK2, contributes to impairment of synaptic plasticity and learning in AS mice. Synaptic SK2 levels are also regulated by protein kinase A (PKA), which phosphorylates SK2 in its C-terminal domain, facilitating its endocytosis. Here, we report that PKA activation restores theta burst stimulation (TBS)-induced long-term potentiation (LTP) in hippocampal slices from AS mice by enhancing SK2 internalization. While TBS-induced SK2 endocytosis is facilitated by PKA activation, SK2 recycling to synaptic membranes after TBS is inhibited by Ube3a. Molecular and cellular studies confirmed that phosphorylation of SK2 in the C-terminal domain increases its ubiquitination and endocytosis. Finally, PKA activation increases SK2 phosphorylation and ubiquitination in Ube3a-overexpressing mice. Our results indicate that, although both Ube3a-mediated ubiquitination and PKA-induced phosphorylation reduce synaptic SK2 levels, phosphorylation is mainly involved in TBS-induced endocytosis, while ubiquitination predominantly inhibits SK2 recycling. Understanding the complex interactions between PKA and Ube3a in the regulation of SK2 synaptic levels might provide new platforms for developing treatments for AS and various forms of autism.


Asunto(s)
Síndrome de Angelman/fisiopatología , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Hipocampo/patología , Plasticidad Neuronal , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/metabolismo , Sinapsis/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Secuencia de Aminoácidos , Síndrome de Angelman/metabolismo , Síndrome de Angelman/patología , Animales , Región CA1 Hipocampal/patología , Región CA1 Hipocampal/fisiopatología , Células COS , Chlorocebus aethiops , Endocitosis , Hipocampo/fisiopatología , Potenciación a Largo Plazo , Ratones , Modelos Moleculares , Mutación , Fosforilación , Dominios Proteicos , Transporte de Proteínas , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/química , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/genética , Ubiquitinación
17.
Front Genet ; 11: 334, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32328086

RESUMEN

Calpains represent a family of calcium-dependent proteases participating in a multitude of functions under physiological or pathological conditions. Calpain-1 is one of the most studied members of the family, is ubiquitously distributed in organs and tissues, and has been shown to be involved in synaptic plasticity and neuroprotection in mammalian brain. Calpain-1 deletion results in a number of phenotypic alterations. While some of these alterations can be explained by the acute functions of calpain-1, the present study was directed at studying alterations in gene expression that could also account for these phenotypic modifications. RNA-seq analysis identified 354 differentially expressed genes (DEGs) in brain of calpain-1 knock-out mice, as compared to their wild-type strain. Most DEGs were classified in 10 KEGG pathways, with the highest representations in Protein Processing in Endoplasmic Reticulum, MAP kinase and Alzheimer's disease pathways. Most DEGs were down-regulated and validation of a number of these genes indicated a corresponding decreased expression of their encoded proteins. The results indicate that calpain-1 is involved in the regulation of a significant number of genes affecting multiple brain functions. They also indicate that mutations in calpain-1 are likely to be involved in a number of brain disorders.

18.
Neurobiol Learn Mem ; 170: 106995, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-30735788

RESUMEN

Calpain-1 and calpain-2 are involved in the regulation of several signaling pathways and neuronal functions in the brain. Our recent studies indicate that calpain-1 is required for hippocampal synaptic plasticity, including long-term depression (LTD) and long-term potentiation (LTP) in field CA1. However, little is known regarding the contributions of calpain-1 to cerebellar synaptic plasticity. Low frequency stimulation (LFS, 5 Hz, 5 min)-induced LTP at parallel fibers to Purkinje cell synapses was markedly impaired in cerebellar slices from calpain-1 knock-out (KO) mice. Application of a selective calpain-2 inhibitor enhanced LFS-induced LTP in both wild-type (WT) and calpain-1 KO mice. Three protocols were used to induce LTD at these synapses: LFS (1 Hz, 15 min), perfusion with high potassium and glutamate (K-Glu) or dihydroxyphenylglycine (DHPG), a mGluR1 agonist. All three forms of LTD were impaired in calpain-1 KO mice. DHPG application stimulated calpain-1 but not calpain-2 in cerebellar slices, and DHPG-induced LTD impairment was reversed by application of a protein phosphatase 2A (PP2A) inhibitor, okadaic acid. As in hippocampus, BDNF induced calpain-1 activation and PH domain and Leucine-rich repeat Protein Phosphatase 1/suprachiasmatic nucleus oscillatory protein (PHLPP1/SCOP) degradation followed by extracellular signal-regulated kinase (ERK) activation, as well as calpain-2 activation leading to degradation of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in cerebellar slices. The role of calpain-1 in associative learning was evaluated in the delay eyeblink conditioning (EBC). Calpain-1 KO mice exhibited significant learning impairment in EBC during the first 2 days of acquisition training. However, after 5 days of training, the percentage of conditioned responses (CRs) between calpain-1 KO and WT mice was identical. Both calpain-1 KO and WT mice exhibited typical extinction patterns. Our results indicate that calpain-1 plays critical roles in multiple forms of synaptic plasticity and associative learning in both hippocampus and cerebellum.


Asunto(s)
Calpaína/fisiología , Cerebelo/fisiología , Condicionamiento Palpebral/fisiología , Plasticidad Neuronal , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Calpaína/genética , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Fosfohidrolasa PTEN/metabolismo , Células de Purkinje/fisiología , Transducción de Señal
19.
Int J Gynaecol Obstet ; 145(2): 233-238, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30805925

RESUMEN

OBJECTIVE: To determine whether ovarian reserve is compromised after hysterectomy with bilateral salpingectomy. METHODS: A prospective longitudinal study was conducted among 84 women who underwent hysterectomy with bilateral salpingectomy at a tertiary medical center in Beijing, China, between August 2, 2015, and January 15, 2017. Serum levels of anti-Müllerian hormone (AMH) and follicle-stimulating hormone (FSH) were measured to assess ovarian function before undergoing the procedure (baseline) and at weeks 1 and 6 after surgery (postoperative period). RESULTS: The median age was 41.61 ± 0.62 years. Age negatively correlated with the serum AMH level at baseline (P<0.001), as well as with preoperative-to-postoperative changes in the concentration of this hormone (P<0.001). Serum AMH levels were lower in the postoperative period versus the preoperative period (P<0.001). By contrast, serum FSH levels were higher in the postoperative period than in the preoperative period (P<0.001). Moreover, no correlation was found with body mass index. CONCLUSIONS: Hysterectomy with bilateral salpingectomy compromised ovarian reserve, with the damage being most severe among younger patients.


Asunto(s)
Histerectomía/efectos adversos , Reserva Ovárica , Salpingectomía/efectos adversos , Adulto , Hormona Antimülleriana/sangre , Beijing , China , Femenino , Hormona Folículo Estimulante/sangre , Humanos , Histerectomía/métodos , Estudios Longitudinales , Periodo Posoperatorio , Periodo Preoperatorio , Estudios Prospectivos , Salpingectomía/métodos
20.
Neuropharmacology ; 144: 337-344, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30408487

RESUMEN

NSI-189 Phosphate, (4-benzylpiperazin-1-yl)-[2-(3-methyl-butylamino)pyridin-3-yl] methanone is a new chemical entity under development for the treatment of MDD, based upon preclinical data demonstrating stimulation of neurogenesis of human hippocampus-derived neural stem cells in vitro and in mouse hippocampus in vivo. Previous studies have examined the tolerability and efficacy of NSI-189 for treating major depressive disorder (MDD). NSI-189 has shown significant potential as a treatment for MDD, with concurrent improvement of a cognition scale in a small double-blind, placebo-controlled study. The current study evaluated its possible application for the treatment of Angelman Syndrome. Incubation of acute hippocampal slices from wild-type mice with NSI-189 resulted in a time- and dose-dependent increase in the magnitude of long-term potentiation (LTP) elicited by theta burst stimulation (TBS). The same protocol enhanced TBS-induced LTP in acute hippocampal slices from AS mice. A short treatment with daily injections of NSI-189 in AS mice reversed impairments in cognitive and motor functions, while it slightly enhanced performance of WT mice. The effects of NSI-189 on synaptic plasticity and cognitive functions were associated with activation of the TrkB and Akt pathways. These results suggest that NSI-189 could represent a potential treatment for AS patients.


Asunto(s)
Aminopiridinas/farmacología , Síndrome de Angelman/tratamiento farmacológico , Fármacos del Sistema Nervioso Central/farmacología , Cognición/efectos de los fármacos , Hipocampo/efectos de los fármacos , Potenciación a Largo Plazo/efectos de los fármacos , Piperazinas/farmacología , Síndrome de Angelman/fisiopatología , Síndrome de Angelman/psicología , Animales , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Hipocampo/fisiopatología , Masculino , Ratones Transgénicos , Actividad Motora/efectos de los fármacos , Técnicas de Cultivo de Tejidos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA