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1.
Nat Commun ; 11(1): 4416, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32887881

RESUMO

Despite the clear association between myocardial injury, heart failure and depressed myocardial energetics, little is known about upstream signals responsible for remodeling myocardial metabolism after pathological stress. Here, we report increased mitochondrial calmodulin kinase II (CaMKII) activation and left ventricular dilation in mice one week after myocardial infarction (MI) surgery. By contrast, mice with genetic mitochondrial CaMKII inhibition are protected from left ventricular dilation and dysfunction after MI. Mice with myocardial and mitochondrial CaMKII overexpression (mtCaMKII) have severe dilated cardiomyopathy and decreased ATP that causes elevated cytoplasmic resting (diastolic) Ca2+ concentration and reduced mechanical performance. We map a metabolic pathway that rescues disease phenotypes in mtCaMKII mice, providing insights into physiological and pathological metabolic consequences of CaMKII signaling in mitochondria. Our findings suggest myocardial dilation, a disease phenotype lacking specific therapies, can be prevented by targeted replacement of mitochondrial creatine kinase or mitochondrial-targeted CaMKII inhibition.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cardiomiopatia Dilatada/metabolismo , Infarto do Miocárdio/fisiopatologia , Animais , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Insuficiência Cardíaca/metabolismo , Ventrículos do Coração/fisiopatologia , Camundongos , Camundongos Transgênicos , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Infarto do Miocárdio/cirurgia , Transdução de Sinais
2.
PLoS Biol ; 18(8): e3000851, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32822389

RESUMO

High levels of the amyloid-beta (Aß) peptide have been shown to disrupt neuronal function and induce hyperexcitability, but it is unclear what effects Aß-associated hyperexcitability may have on tauopathy pathogenesis or propagation in vivo. Using a novel transgenic mouse line to model the impact of human APP (hAPP)/Aß accumulation on tauopathy in the entorhinal cortex-hippocampal (EC-HIPP) network, we demonstrate that hAPP overexpression aggravates EC-Tau aggregation and accelerates pathological tau spread into the hippocampus. In vivo recordings revealed a strong role for hAPP/Aß, but not tau, in the emergence of EC neuronal hyperactivity and impaired theta rhythmicity. Chronic chemogenetic attenuation of EC neuronal hyperactivity led to reduced hAPP/Aß accumulation and reduced pathological tau spread into downstream hippocampus. These data strongly support the hypothesis that in Alzheimer's disease (AD), Aß-associated hyperactivity accelerates the progression of pathological tau along vulnerable neuronal circuits, and demonstrates the utility of chronic, neuromodulatory approaches in ameliorating AD pathology in vivo.


Assuntos
Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Córtex Entorrinal/metabolismo , Tauopatias/genética , Proteínas tau/genética , Potenciais de Ação/fisiologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Doença de Alzheimer/terapia , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Dependovirus/genética , Dependovirus/metabolismo , Modelos Animais de Doenças , Eletrodos Implantados , Córtex Entorrinal/patologia , Feminino , Regulação da Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios/metabolismo , Neurônios/patologia , Agregados Proteicos , Técnicas Estereotáxicas , Tauopatias/metabolismo , Tauopatias/patologia , Tauopatias/terapia , Ritmo Teta/fisiologia , Transdução Genética , Transgenes , Proteínas tau/metabolismo
3.
J Virol ; 94(20)2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32796063

RESUMO

Alpha/beta interferon (IFN-α/ß) signaling through the IFN-α/ß receptor (IFNAR) is essential to limit virus dissemination throughout the central nervous system (CNS) following many neurotropic virus infections. However, the distinct expression patterns of factors associated with the IFN-α/ß pathway in different CNS resident cell populations implicate complex cooperative pathways in IFN-α/ß induction and responsiveness. Here we show that mice devoid of IFNAR1 signaling in calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα) expressing neurons (CaMKIIcre:IFNARfl/fl mice) infected with a mildly pathogenic neurotropic coronavirus (mouse hepatitis virus A59 strain [MHV-A59]) developed severe encephalomyelitis with hind-limb paralysis and succumbed within 7 days. Increased virus spread in CaMKIIcre:IFNARfl/fl mice compared to IFNARfl/fl mice affected neurons not only in the forebrain but also in the mid-hind brain and spinal cords but excluded the cerebellum. Infection was also increased in glia. The lack of viral control in CaMKIIcre:IFNARfl/fl relative to control mice coincided with sustained Cxcl1 and Ccl2 mRNAs but a decrease in mRNA levels of IFNα/ß pathway genes as well as Il6, Tnf, and Il1ß between days 4 and 6 postinfection (p.i.). T cell accumulation and IFN-γ production, an essential component of virus control, were not altered. However, IFN-γ responsiveness was impaired in microglia/macrophages irrespective of similar pSTAT1 nuclear translocation as in infected controls. The results reveal how perturbation of IFN-α/ß signaling in neurons can worsen disease course and disrupt complex interactions between the IFN-α/ß and IFN-γ pathways in achieving optimal antiviral responses.IMPORTANCE IFN-α/ß induction limits CNS viral spread by establishing an antiviral state, but also promotes blood brain barrier integrity, adaptive immunity, and activation of microglia/macrophages. However, the extent to which glial or neuronal signaling contributes to these diverse IFN-α/ß functions is poorly understood. Using a neurotropic mouse hepatitis virus encephalomyelitis model, this study demonstrated an essential role of IFN-α/ß receptor 1 (IFNAR1) specifically in neurons to control virus spread, regulate IFN-γ signaling, and prevent acute mortality. The results support the notion that effective neuronal IFNAR1 signaling compensates for their low basal expression of genes in the IFN-α/ß pathway compared to glia. The data further highlight the importance of tightly regulated communication between the IFN-α/ß and IFN-γ signaling pathways to optimize antiviral IFN-γ activity.


Assuntos
Sistema Nervoso Central/virologia , Interferon Tipo I/metabolismo , Interferon gama/metabolismo , Macrófagos/metabolismo , Microglia/metabolismo , Neurônios/metabolismo , Transdução de Sinais , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Sistema Nervoso Central/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Modelos Animais de Doenças , Encefalomielite/imunologia , Encefalomielite/virologia , Macrófagos/virologia , Camundongos , Camundongos Mutantes , Microglia/virologia , Vírus da Hepatite Murina/fisiologia , Neurônios/virologia , Infiltração de Neutrófilos , Receptor de Interferon alfa e beta/deficiência , Receptor de Interferon alfa e beta/genética , Receptor de Interferon alfa e beta/metabolismo , Replicação Viral
4.
Life Sci ; 259: 118290, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32822713

RESUMO

AIMS: Atrial fibrillation (AF) is a common arrhythmia which is associated with higher risk of stroke, heart failure and all-cause mortality. Abnormal Ca2+ handling in diabetes mellitus (DM) can cause delayed depolarization involved with increased NCX activity. Complicated mechanisms are involved in atrial remodeling, of which CaMKII may be a key node signal. Therefore, we intend to explore whether CaMKII activation induces atrial electrical remodeling by regulating NCX expression in this study. MAIN METHODS: Adult male SD rats were used to establish a diabetic rat model, divided into three groups: the control group, DM group and allopurinol group. Hemodynamic and ECG indicators were recorded, after which electrophysiological studies were conducted. The protein expression of CaMKII, p-CaMKII, XO, MnSOD and NCX was measured by Western blot and immunohistochemistry. H&E and Masson staining were applied for observing myocardial fibrosis. HL-1 cells were cultured for the measurement of ROS generation. KEY FINDINGS: The arrangement of atrial myocytes was disordered and the collagen volume fraction of the atrium tissue was elevated in the DM group compared with the control group, and improved by allopurinol. Higher incidence of inducible AF, reduced conduction velocity and higher conduction inhomogeneity were observed in diabetic rats. These electrophysiological abnormalities were accompanied by higher oxidative stress and protein expression of p-CaMKII and NCX. Allopurinol prevented the development of these abnormal changes. SIGNIFICANCE: Allopurinol can improve atrial electrical remodeling by inhibiting CaMKII activity and protein expression of NCX. These data indicate xanthine oxidase inhibition can reduce oxidative stress and ameliorate atrial electrical remodeling.


Assuntos
Alopurinol/farmacologia , Remodelamento Atrial/efeitos dos fármacos , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Diabetes Mellitus Experimental/complicações , Cardiomiopatias Diabéticas/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Xantina Oxidase/antagonistas & inibidores , Animais , Western Blotting , Ecocardiografia , Hemodinâmica/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real
5.
Nat Commun ; 11(1): 3467, 2020 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32651378

RESUMO

Modulation of gap junction-mediated electrical synapses is a common form of neural plasticity. However, the behavioral consequence of the modulation and the underlying molecular cellular mechanisms are not understood. Here, using a C. elegans circuit of interneurons that are connected by gap junctions, we show that modulation of the gap junctions facilitates olfactory learning. Learning experience weakens the gap junctions and induces a repulsive sensory response to the training odorants, which together decouple the responses of the interneurons to the training odorants to generate learned olfactory behavior. The weakening of the gap junctions results from downregulation of the abundance of a gap junction molecule, which is regulated by cell-autonomous function of the worm homologs of a NMDAR subunit and CaMKII. Thus, our findings identify the function of a gap junction modulation in an in vivo model of learning and a conserved regulatory pathway underlying the modulation.


Assuntos
Junções Comunicantes/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Interneurônios/metabolismo , Aprendizagem/fisiologia , Memória/fisiologia
6.
PLoS Comput Biol ; 16(7): e1008015, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32678848

RESUMO

Calmodulin-dependent kinase II (CaMKII) has long been known to play an important role in learning and memory as well as long term potentiation (LTP). More recently it has been suggested that it might be involved in the time averaging of synaptic signals, which can then lead to the high precision of information stored at a single synapse. However, the role of the scaffolding molecule, neurogranin (Ng), in governing the dynamics of CaMKII is not yet fully understood. In this work, we adopt a rule-based modeling approach through the Monte Carlo method to study the effect of Ca2+ signals on the dynamics of CaMKII phosphorylation in the postsynaptic density (PSD). Calcium surges are observed in synaptic spines during an EPSP and back-propagating action potential due to the opening of NMDA receptors and voltage dependent calcium channels. Using agent-based models, we computationally investigate the dynamics of phosphorylation of CaMKII monomers and dodecameric holoenzymes. The scaffolding molecule, Ng, when present in significant concentration, limits the availability of free calmodulin (CaM), the protein which activates CaMKII in the presence of calcium. We show that Ng plays an important modulatory role in CaMKII phosphorylation following a surge of high calcium concentration. We find a non-intuitive dependence of this effect on CaM concentration that results from the different affinities of CaM for CaMKII depending on the number of calcium ions bound to the former. It has been shown previously that in the absence of phosphatase, CaMKII monomers integrate over Ca2+ signals of certain frequencies through autophosphorylation (Pepke et al, Plos Comp. Bio., 2010). We also study the effect of multiple calcium spikes on CaMKII holoenzyme autophosphorylation, and show that in the presence of phosphatase, CaMKII behaves as a leaky integrator of calcium signals, a result that has been recently observed in vivo. Our models predict that the parameters of this leaky integrator are finely tuned through the interactions of Ng, CaM, CaMKII, and PP1, providing a mechanism to precisely control the sensitivity of synapses to calcium signals. Author Summary not valid for PLOS ONE submissions.


Assuntos
Sinalização do Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Calmodulina/metabolismo , Neurogranina/metabolismo , Potenciais de Ação , Animais , Área Sob a Curva , Biologia Computacional , Simulação por Computador , Potenciação de Longa Duração , Camundongos , Método de Monte Carlo , Plasticidade Neuronal , Fosforilação , Densidade Pós-Sináptica/metabolismo , Ligação Proteica , Receptores de N-Metil-D-Aspartato/metabolismo , Software , Sinapses/fisiologia , Fatores de Tempo
7.
PLoS One ; 15(7): e0233161, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32645049

RESUMO

The beta blockers carvedilol, bisoprolol, and sustained-release metoprolol succinate reduce readmissions and mortality among patients with heart failure with reduced ejection fraction (HFrEF), based upon clinical trial and registry studies. Results from these studies may not generalize to the typical patient with HFrEF. We conducted a retrospective cohort study of beneficiaries in the Medicare 5% sample hospitalized for HFrEF between 2007 and 2013 and were discharged alive. We compared the 30-day and 365-day heart failure (HF) readmission, all-cause readmission, and mortality rates between beneficiaries who filled a prescription for an evidence-based beta blocker and those who did not after being hospitalized for HFrEF. Out of 12,127 beneficiaries hospitalized for HFrEF, 20% were readmitted for HF, 62% were readmitted for any cause, and 27% died within 365 days. In competing risk models adjusted for demographics, healthcare utilization, and comorbidities, beta blocker use was associated with a lower risk of HF readmission between 8-365 days post discharge (hazard ratio 0.79 [95% confidence interval 0.76, 0.82]), but was not significantly associated with all-cause readmission (1.02 [0.97-1.07]). In Cox models adjusted for the same covariates, beta blocker use was associated with lower mortality 8-365 days post discharge (0.65 [0.60-0.71]). Results were similar when follow up was truncated at 30 days post discharge. Increasing the use of beta blockers following HFrEF hospitalization may not decrease all-cause readmissions among Medicare beneficiaries, but may reduce HF-specific readmissions and mortality.


Assuntos
Astrócitos/virologia , Proteína Rica em Cisteína 61/metabolismo , Infecção por Zika virus/virologia , Zika virus/fisiologia , Animais , Astrócitos/metabolismo , Astrocitoma/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Linhagem Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Proteína Rica em Cisteína 61/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Serina Endopeptidases/metabolismo , Regulação para Cima , Proteínas não Estruturais Virais/metabolismo , Proteínas Virais/metabolismo , Replicação Viral , Infecção por Zika virus/metabolismo
8.
PLoS One ; 15(7): e0236547, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32716920

RESUMO

Occlusal disharmony leads to morphological changes in the hippocampus and osteopenia of the lumbar vertebra and long bones in mice, and causes stress. Various types of stress are associated with increased incidence of cardiovascular disease, but the relationship between occlusal disharmony and cardiovascular disease remain poorly understood. Therefore, in this work, we examined the effects of occlusal disharmony on cardiac homeostasis in bite-opening (BO) mice, in which a 0.7 mm space was introduced by cementing a suitable applicance onto the mandibular incisior. We first examined the effects of BO on the level of serum corticosterone, a key biomarker for stress, and on heart rate variability at 14 days after BO treatment, compared with baseline. BO treatment increased serum corticosterone levels by approximately 3.6-fold and the low frequency/high frequency ratio, an index of sympathetic nervous activity, was significantly increased by approximately 4-fold by the BO treatment. We then examined the effects of BO treatment on cardiac homeostasis in mice treated or not treated with the non-selective ß-blocker propranolol for 2 weeks. Cardiac function was significantly decreased in the BO group compared to the control group, but propranolol ameliorated the dysfunction. Cardiac fibrosis, myocyte apoptosis and myocyte oxidative DNA damage were significantly increased in the BO group, but propranolol blocked these changes. The BO-induced cardiac dysfunction was associated with increased phospholamban phosphorylation at threonine-17 and serine-16, as well as inhibition of Akt/mTOR signaling and autophagic flux. These data suggest that occlusal disharmony might affect cardiac homeostasis via alteration of the autonomic nervous system.


Assuntos
Apoptose , Dano ao DNA , Miocárdio/patologia , Estresse Fisiológico , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Corticosterona/sangue , Eletrocardiografia , Fibrose , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Estresse Oxidativo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo
10.
Life Sci ; 253: 117675, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32360621

RESUMO

AIMS: Gliomas are responsible for the majority of deaths from primary brain tumours. Sevoflurane showed inhibition effects on the tumor progression in vitro. However, whether sevoflurane could affect the stemness of glioma stem cells (GSCs) and the potential molecular mechanism have not been well elucidated. MAIN METHODS: Effects of sevoflurane on cell viability, proliferation and invasion ability of glioma cells as well as tumor growth in vivo were assessed. Sphere formation assay was performed to evaluate the effect of sevoflurane on the stemness of GSCs. Effects of sevoflurane on mitochondrial function was evaluated by intracellular/mitochondrial reactive oxygen species (ROS) level and mitochondrial membrane potential. Expression levels of proliferation-related proteins, stemness markers and proteins in CaMKII/JNK cascade were measured by Western blot. KEY FINDINGS: Sevoflurane inhibited the viability, proliferation and invasion ability of glioma cells (U87MG and U373MG). Western blot showed that sevoflurane decreased the expression levels of proliferation and invasion-related proteins. Sphere formation ability of GSCs, expression levels of stemness markers and mitochondrial function were significantly suppressed by sevoflurane. Moreover, sevoflurane treatment significantly increased the Ca2+ concentration and stimulated phosphorylation of CaMKII, JNK and IRS1. Ca2+ chelator BAPTA-AM combined with sevoflurane synergistically inhibited colony forming ability and the expression levels of proliferation-related proteins and stemness markers. In addition, the in vivo study further confirmed that sevoflurane inhibited tumor growth via Ca2+-dependent CaMKII/JNK cascade. SIGNIFICANCE: The present study demonstrated that sevoflurane inhibited glioma tumorigenesis and modulated the cancer stem cell-like properties and mitochondrial membrane potential via activation of Ca2+-dependent CaMKII/JNK cascade.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , MAP Quinase Quinase 4/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Células-Tronco Neoplásicas/efeitos dos fármacos , Sevoflurano/metabolismo , Sevoflurano/farmacologia , Animais , Cálcio/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Quelantes/metabolismo , Ácido Egtázico/análogos & derivados , Ácido Egtázico/metabolismo , Glioma , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosforilação , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
11.
Nat Commun ; 11(1): 2679, 2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32471994

RESUMO

The cation channel transient receptor potential vanilloid 4 (TRPV4) is one of the few identified ion channels that can directly cause inherited neurodegeneration syndromes, but the molecular mechanisms are unknown. Here, we show that in vivo expression of a neuropathy-causing TRPV4 mutant (TRPV4R269C) causes dose-dependent neuronal dysfunction and axonal degeneration, which are rescued by genetic or pharmacological blockade of TRPV4 channel activity. TRPV4R269C triggers increased intracellular Ca2+ through a Ca2+/calmodulin-dependent protein kinase II (CaMKII)-mediated mechanism, and CaMKII inhibition prevents both increased intracellular Ca2+ and neurotoxicity in Drosophila and cultured primary mouse neurons. Importantly, TRPV4 activity impairs axonal mitochondrial transport, and TRPV4-mediated neurotoxicity is modulated by the Ca2+-binding mitochondrial GTPase Miro. Our data highlight an integral role for CaMKII in neuronal TRPV4-associated Ca2+ responses, the importance of tightly regulated Ca2+ dynamics for mitochondrial axonal transport, and the therapeutic promise of TRPV4 antagonists for patients with TRPV4-related neurodegenerative diseases.


Assuntos
Sinalização do Cálcio/fisiologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Drosophila melanogaster/metabolismo , Doenças Neurodegenerativas/genética , Canais de Cátion TRPV/genética , Animais , Animais Geneticamente Modificados , Axônios/patologia , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Células Cultivadas , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/patologia , Asas de Animais/crescimento & desenvolvimento
13.
Nature ; 579(7800): 555-560, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32214250

RESUMO

Dopamine D2 receptors (D2Rs) are densely expressed in the striatum and have been linked to neuropsychiatric disorders such as schizophrenia1,2. High-affinity binding of dopamine suggests that D2Rs detect transient reductions in dopamine concentration (the dopamine dip) during punishment learning3-5. However, the nature and cellular basis of D2R-dependent behaviour are unclear. Here we show that tone reward conditioning induces marked stimulus generalization in a manner that depends on dopamine D1 receptors (D1Rs) in the nucleus accumbens (NAc) of mice, and that discrimination learning refines the conditioning using a dopamine dip. In NAc slices, a narrow dopamine dip (as short as 0.4 s) was detected by D2Rs to disinhibit adenosine A2A receptor (A2AR)-mediated enlargement of dendritic spines in D2R-expressing spiny projection neurons (D2-SPNs). Plasticity-related signalling by Ca2+/calmodulin-dependent protein kinase II and A2ARs in the NAc was required for discrimination learning. By contrast, extinction learning did not involve dopamine dips or D2-SPNs. Treatment with methamphetamine, which dysregulates dopamine signalling, impaired discrimination learning and spine enlargement, and these impairments were reversed by a D2R antagonist. Our data show that D2Rs refine the generalized reward learning mediated by D1Rs.


Assuntos
Espinhas Dendríticas/fisiologia , Aprendizagem por Discriminação/fisiologia , Receptores de Dopamina D2/metabolismo , Animais , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Condicionamento Clássico/efeitos dos fármacos , Espinhas Dendríticas/efeitos dos fármacos , Aprendizagem por Discriminação/efeitos dos fármacos , Dopamina/metabolismo , Antagonistas dos Receptores de Dopamina D2/farmacologia , Extinção Psicológica/efeitos dos fármacos , Masculino , Metanfetamina/antagonistas & inibidores , Metanfetamina/farmacologia , Camundongos , Plasticidade Neuronal , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Optogenética , Receptor A2A de Adenosina/metabolismo , Receptores de Dopamina D1/metabolismo , Recompensa , Transdução de Sinais/efeitos dos fármacos , Sinapses/metabolismo
14.
Arch Biochem Biophys ; 685: 108348, 2020 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-32198047

RESUMO

Memory formation transpires to be by activation and persistent modification of synapses. A chain of biochemical events accompany synaptic activation and culminate in memory formation. These biochemical events are steered by interplay and modulation of various synaptic proteins, achieved by conformational changes and phosphorylation/dephosphorylation of these proteins. Calcium/calmodulin dependent protein kinase II (CaMKII) and N-methyl-d-aspartate receptors (NMDARs) are synaptic proteins whose interactions play a pivotal role in learning and memory process. Catalytic activity of CaMKII is modulated upon its interaction with the GluN2B subunit of NMDAR. The structural basis of this interaction is not clearly understood. We have investigated the role of Glu60 of α-CaMKII, a conserved residue present in the ATP binding region of kinases, in the regulation of catalysis of CaMKII by GluN2B. Mutation of Glu60 to Gly exerts different effects on the kinetic parameters of phosphorylation of GluN2B and GluN2A, of which only GluN2B binds to the T-site of CaMKII. GluN2B induced modulation of the kinetic parameters of peptide substrate was altered in the E60G mutant. The mutation almost abolished the modulation of the apparent Km value for protein substrate. However, although kinetic parameters for ATP were altered by mutating Glu60, modulation of the apparent Km value for ATP by GluN2B seen in WT was exhibited by the E60G mutant of α-CaMKII. Hence our results posit that the communication of the T-site of CaMKII with protein substrate binding region of active site is mediated through Glu60 while the communication of the T-site with the ATP binding region is not entirely dependent on Glu60.


Assuntos
Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Ácido Glutâmico/química , Receptores de N-Metil-D-Aspartato/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/química , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Calmodulina/metabolismo , Domínio Catalítico , Células HEK293 , Humanos , Cinética , Mutação , Ligação Proteica
15.
J Neurosci ; 40(16): 3231-3249, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32144180

RESUMO

Endogenous neuropeptide Y (NPY) and corticotrophin-releasing factor (CRF) modulate the responses of the basolateral amygdala (BLA) to stress and are associated with the development of stress resilience and vulnerability, respectively. We characterized persistent effects of repeated NPY and CRF treatment on the structure and function of BLA principal neurons in a novel organotypic slice culture (OTC) model of male rat BLA, and examined the contributions of specific NPY receptor subtypes to these neural and behavioral effects. In BLA principal neurons within the OTCs, repeated NPY treatment caused persistent attenuation of excitatory input and induced dendritic hypotrophy via Y5 receptor activation; conversely, CRF increased excitatory input and induced hypertrophy of BLA principal neurons. Repeated treatment of OTCs with NPY followed by an identical treatment with CRF, or vice versa, inhibited or reversed all structural changes in OTCs. These structural responses to NPY or CRF required calcineurin or CaMKII, respectively. Finally, repeated intra-BLA injections of NPY or a Y5 receptor agonist increased social interaction, a validated behavior for anxiety, and recapitulated structural changes in BLA neurons seen in OTCs, while a Y5 receptor antagonist prevented NPY's effects both on behavior and on structure. These results implicate the Y5 receptor in the long-term, anxiolytic-like effects of NPY in the BLA, consistent with an intrinsic role in stress buffering, and highlight a remarkable mechanism by which BLA neurons may adapt to different levels of stress. Moreover, BLA OTCs offer a robust model to study mechanisms associated with resilience and vulnerability to stress in BLA.SIGNIFICANCE STATEMENT Within the basolateral amygdala (BLA), neuropeptide Y (NPY) is associated with buffering the neural stress response induced by corticotropin releasing factor, and promoting stress resilience. We used a novel organotypic slice culture model of BLA, complemented with in vivo studies, to examine the cellular mechanisms associated with the actions of NPY. In organotypic slice cultures, repeated NPY treatment reduces the complexity of the dendritic extent of anxiogenic BLA principal neurons, making them less excitable. NPY, via activation of Y5 receptors, additionally inhibits and reverses the increases in dendritic extent and excitability induced by the stress hormone, corticotropin releasing factor. This NPY-mediated neuroplasticity indicates that resilience or vulnerability to stress may thus involve neuropeptide-mediated dendritic remodeling in BLA principal neurons.


Assuntos
Complexo Nuclear Basolateral da Amígdala/efeitos dos fármacos , Hormônio Liberador da Corticotropina/farmacologia , Dendritos/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Neuropeptídeo Y/farmacologia , Receptores de Neuropeptídeo Y/agonistas , Comportamento Social , Animais , Complexo Nuclear Basolateral da Amígdala/metabolismo , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Calcineurina/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Dendritos/metabolismo , Masculino , Plasticidade Neuronal/fisiologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores de Neuropeptídeo Y/metabolismo , Resiliência Psicológica
16.
PLoS Comput Biol ; 16(2): e1006991, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32049957

RESUMO

Calmodulin sits at the center of molecular mechanisms underlying learning and memory. Its complex and sometimes opposite influences, mediated via the binding to various proteins, are yet to be fully understood. Calcium/calmodulin-dependent protein kinase II (CaMKII) and calcineurin (CaN) both bind open calmodulin, favoring Long-Term Potentiation (LTP) or Depression (LTD) respectively. Neurogranin binds to the closed conformation of calmodulin and its impact on synaptic plasticity is less clear. We set up a mechanistic computational model based on allosteric principles to simulate calmodulin state transitions and its interactions with calcium ions and the three binding partners mentioned above. We simulated calcium spikes at various frequencies and show that neurogranin regulates synaptic plasticity along three modalities. At low spike frequencies, neurogranin inhibits the onset of LTD by limiting CaN activation. At intermediate frequencies, neurogranin facilitates LTD, but limits LTP by precluding binding of CaMKII with calmodulin. Finally, at high spike frequencies, neurogranin promotes LTP by enhancing CaMKII autophosphorylation. While neurogranin might act as a calmodulin buffer, it does not significantly preclude the calmodulin opening by calcium. On the contrary, neurogranin synchronizes the opening of calmodulin's two lobes and promotes their activation at specific frequencies. Neurogranin suppresses basal CaN activity, thus increasing the chance of CaMKII trans-autophosphorylation at high-frequency calcium spikes. Taken together, our study reveals dynamic regulatory roles played by neurogranin on synaptic plasticity, which provide mechanistic explanations for opposing experimental findings.


Assuntos
Potenciais de Ação , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cálcio/metabolismo , Neurogranina/fisiologia , Animais , Ativação Enzimática/fisiologia , Potenciação de Longa Duração , Depressão Sináptica de Longo Prazo/fisiologia , Plasticidade Neuronal , Fosforilação
17.
Nat Commun ; 11(1): 640, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005806

RESUMO

Reduced food intake is common to many pathological conditions, such as infection and toxin exposure. However, cortical circuits that mediate feeding responses to these threats are less investigated. The anterior insular cortex (aIC) is a core region that integrates interoceptive states and emotional awareness and consequently guides behavioral responses. Here, we demonstrate that the right-side aIC CamKII+ (aICCamKII) neurons in mice are activated by aversive visceral signals. Hyperactivation of the right-side aICCamKII neurons attenuates food consumption, while inhibition of these neurons increases feeding and reverses aversive stimuli-induced anorexia and weight loss. Similar manipulation at the left-side aIC does not cause significant behavioral changes. Furthermore, virus tracing reveals that aICCamKII neurons project directly to the vGluT2+ neurons in the lateral hypothalamus (LH), and the right-side aICCamKII-to-LH pathway mediates feeding suppression. Our studies uncover a circuit from the cortex to the hypothalamus that senses aversive visceral signals and controls feeding behavior.


Assuntos
Agentes Aversivos/toxicidade , Córtex Cerebral/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Animais , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Córtex Cerebral/efeitos dos fármacos , Feminino , Região Hipotalâmica Lateral/metabolismo , Hipotálamo/citologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vias Neurais/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo
18.
J Neurosci ; 40(10): 2000-2014, 2020 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019829

RESUMO

The activation of neuronal plasma membrane Ca2+ channels stimulates many intracellular responses. Scaffolding proteins can preferentially couple specific Ca2+ channels to distinct downstream outputs, such as increased gene expression, but the molecular mechanisms that underlie the exquisite specificity of these signaling pathways are incompletely understood. Here, we show that complexes containing CaMKII and Shank3, a postsynaptic scaffolding protein known to interact with L-type calcium channels (LTCCs), can be specifically coimmunoprecipitated from mouse forebrain extracts. Activated purified CaMKIIα also directly binds Shank3 between residues 829 and 1130. Mutation of Shank3 residues 949Arg-Arg-Lys951 to three alanines disrupts CaMKII binding in vitro and CaMKII association with Shank3 in heterologous cells. Our shRNA/rescue studies revealed that Shank3 binding to both CaMKII and LTCCs is important for increased phosphorylation of the nuclear CREB transcription factor and expression of c-Fos induced by depolarization of cultured hippocampal neurons. Thus, this novel CaMKII-Shank3 interaction is essential for the initiation of a specific long-range signal from LTCCs in the plasma membrane to the nucleus that is required for activity-dependent changes in neuronal gene expression during learning and memory.SIGNIFICANCE STATEMENT Precise neuronal expression of genes is essential for normal brain function. Proteins involved in signaling pathways that underlie activity-dependent gene expression, such as CaMKII, Shank3, and L-type calcium channels, are often mutated in multiple neuropsychiatric disorders. Shank3 and CaMKII were previously shown to bind L-type calcium channels, and we show here that Shank3 also binds to CaMKII. Our data show that each of these interactions is required for depolarization-induced phosphorylation of the CREB nuclear transcription factor, which stimulates the expression of c-Fos, a neuronal immediate early gene with key roles in synaptic plasticity, brain development, and behavior.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Núcleo Celular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Animais , Regulação da Expressão Gênica/fisiologia , Hipocampo/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/fisiologia
19.
Oxid Med Cell Longev ; 2020: 3690123, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32064022

RESUMO

Thioridazine (THIO) is a phenothiazine derivative that is mainly used for the treatment of psychotic disorders. However, cardiac arrhythmias especially QT interval prolongation associated with the application of this compound have received serious attention after its introduction into clinical practice, and the mechanisms underlying the cardiotoxicity induced by THIO have not been well defined. The present study was aimed at exploring the long-term effects of THIO on the hERG and L-type calcium channels, both of which are relevant to the development of QT prolongation. The hERG current (I hERG) and the calcium current (I Ca-L) were measured by patch clamp techniques. Protein levels were analyzed by Western blot, and channel-chaperone interactions were determined by coimmunoprecipitation. Reactive oxygen species (ROS) were determined by flow cytometry and laser scanning confocal microscopy. Our results demonstrated that THIO induced hERG channel deficiency but did not alter channel kinetics. THIO promoted ROS production and stimulated endoplasmic reticulum (ER) stress and the related proteins. The ROS scavenger N-acetyl cysteine (NAC) significantly attenuated hERG reduction induced by THIO and abolished the upregulation of ER stress marker proteins. Meanwhile, THIO increased the degradation of hERG channels via disrupting hERG-Hsp70 interactions. The disordered hERG proteins were degraded in proteasomes after ubiquitin modification. On the other hand, THIO increased I Ca-L density and intracellular Ca2+ ([Ca2+]i) in neonatal rat ventricular cardiomyocytes (NRVMs). The specific CaMKII inhibitor KN-93 attenuated the intracellular Ca2+ overload, indicating that ROS-mediated CaMKII activation promoted calcium channel activation induced by THIO. Optical mapping analysis demonstrated the slowing effects of THIO on cardiac repolarization in mouse hearts. THIO significantly prolonged APD50 and APD90 and increased the incidence of early afterdepolarizations (EADs). In human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), THIO also resulted in APD prolongation. In conclusion, dysfunction of hERG channel proteins and activation of L-type calcium channels via ROS production might be the ionic mechanisms for QT prolongation induced by THIO.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Canais de Cálcio Tipo L/metabolismo , Cardiotoxicidade/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Canais de Potássio Éter-A-Go-Go/metabolismo , Tioridazina/toxicidade , Potenciais de Ação/fisiologia , Animais , Benzilaminas/farmacologia , Cálcio/metabolismo , Canais de Cálcio Tipo L/fisiologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Estresse do Retículo Endoplasmático/genética , Canais de Potássio Éter-A-Go-Go/fisiologia , Células HEK293 , Proteínas de Choque Térmico HSP70/metabolismo , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Masculino , Camundongos , Miócitos Cardíacos/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Sulfonamidas/farmacologia , Ubiquitinação
20.
Biochem Biophys Res Commun ; 524(2): 431-438, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32007269

RESUMO

AIMS: Ca2+/calmodulin-dependent protein kinase II (CaMKII) has been shown to induce aberrant Ca2+ release from the cardiac ryanodine receptor (RyR2) in various diseased hearts. However, the precise pathogenic mechanism remains to be elucidated. Here, we investigated the effect of dantrolene (DAN): a RyR2 stabilizer on local Ca2+ release, cardiac function, and lethal arrhythmia in CaMKIIδc transgenic (TG) mice. METHODS AND RESULTS: The TG mice showed an increase in left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) with a reduction in LV fractional shortening (LVFS). The phosphorylation levels of Ser2814 in RyR2 and Thr287 in CaMKII increased in TG mice. In TG cardiomyocytes, peak cell shortening (CS) decreased, and the frequency of spontaneous Ca2+ transients (sCaTs) increased. Endogenous RyR2-associated calmodulin (CaM) markedly decreased in TG cardiomyocytes. After chronic DAN treatment for 1 month, LVESD (but not LVEDD) decreased with an increase in LVFS. In the chronic DAN-treated cardiomyocytes, CS increased, sCaTs decreased, and the endogenous CaM binding to RyR2 normally restored. The phosphorylation levels of Ser2814 in RyR2 and Thr287 in CaMKII remained elevated even after DAN treatment. Moreover, in TG mice, chronic DAN treatment prevented sustained ventricular tachycardia induced by epinephrine. CONCLUSIONS: Defective association of CaM with RyR2 is most likely to be involved in the pathogenesis of CaMKII-mediated cardiac dysfunction and lethal arrhythmia.


Assuntos
Arritmias Cardíacas/prevenção & controle , Arritmias Cardíacas/fisiopatologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Coração/fisiopatologia , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Animais , Arritmias Cardíacas/genética , Arritmias Cardíacas/metabolismo , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Células Cultivadas , Dantroleno/uso terapêutico , Técnicas de Introdução de Genes , Coração/efeitos dos fármacos , Camundongos , Camundongos Transgênicos , Relaxantes Musculares Centrais/uso terapêutico , Fosforilação/efeitos dos fármacos , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Regulação para Cima/efeitos dos fármacos
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