RESUMO
BACKGROUND: People of all nationalities and social classes are now affected by the growing issue of hypertension. Over time, there has been a consistent rise in the fatality rate. A range of therapeutic compounds, on the other hand, are often used to handle hypertension. OBJECTIVES: The objectives of this study are first to design potential antihypertensive drugs based on the DHP scaffold, secondly, to analyse drug-likeness properties of the ligands and investigate their molecular mechanisms of binding to the model protein Cav1.2 and finally to synthesise the best ligand. MATERIALS AND METHODS: Due to the lack of 3D structures for human Cav1.2, the protein structure was modelled using a homology modelling approach. A protein-ligand complex's strength and binding interaction were investigated using molecular docking and molecular dynamics techniques. DFT-based electronic properties of the ligand were calculated using the M06-2X/ def2- TZVP level of theory. The SwissADME website was used to study the ADMET properties. RESULTS: In this study, a series of DHP compounds (19 compounds) were properly designed to act as calcium channel blockers. Among these compounds, compound 16 showed excellent binding scores (-11.6 kcal/mol). This compound was synthesised with good yield and characterised. To assess the structural features of the synthesised molecule quantum chemical calculations were performed. CONCLUSION: Based on molecular docking, molecular dynamics simulations, and drug-likeness properties of compound 16 can be used as a potential calcium channel blocker.
Assuntos
Bloqueadores dos Canais de Cálcio , Canais de Cálcio Tipo L , Di-Hidropiridinas , Desenho de Fármacos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Bloqueadores dos Canais de Cálcio/farmacologia , Bloqueadores dos Canais de Cálcio/síntese química , Bloqueadores dos Canais de Cálcio/química , Di-Hidropiridinas/farmacologia , Di-Hidropiridinas/química , Di-Hidropiridinas/síntese química , Humanos , Canais de Cálcio Tipo L/metabolismo , Teoria da Densidade Funcional , Ligantes , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/síntese química , Anti-Hipertensivos/química , Simulação por ComputadorRESUMO
The L-type Ca2+ channel (LTCC, also known as Cav1,2) is involved in the regulation of key neuronal functions, such as dendritic information integration, cell survival, and neuronal gene expression. Clinical studies have shown an association between L-type calcium channels and the onset of depression, although the precise mechanisms remain unclear. The development of depression results from a combination of environmental and genetic factors. DNA methylation, a significant epigenetic modification, plays a regulatory role in the pathogenesis of psychiatric disorders such as posttraumatic stress disorder (PTSD), depression, and autism. In our study, we observed reduced Dnmt3a expression levels in the hippocampal DG region of mice with LPS-induced depression compared to control mice. The antidepressant Venlafaxine was able to increase Dnmt3a expression levels. Conversely, Bay K 8644, an agonist of the L-type Ca2+ channel, partially ameliorated depression-like behaviors but did not elevate Dnmt3a expression levels. Furthermore, when we manipulated DNA methylation levels during Bay K 8644 intervention in depression-like models, we found that enhancing the expression of Dnmt3a could improve LPS-induced depression/anxiety-like behaviors, while inhibiting DNA methylation exacerbated anxiety-like behaviors, the combined use of BAY K 8644 and L-methionine can better improve depressive-like behavior. These findings indicate that DNA methylation plays a role in the regulation of depression-like behaviors by the L-type Ca2+ channel, and further research is needed to elucidate the interactions between DNA methylation and L-type Ca2+ channels.
Assuntos
Éster Metílico do Ácido 3-Piridinacarboxílico, 1,4-Di-Hidro-2,6-Dimetil-5-Nitro-4-(2-(Trifluormetil)fenil) , Agonistas dos Canais de Cálcio , Canais de Cálcio Tipo L , Metilação de DNA , DNA Metiltransferase 3A , Depressão , Metionina , Animais , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/efeitos dos fármacos , Metionina/farmacologia , Masculino , Depressão/tratamento farmacológico , Depressão/metabolismo , Camundongos , Agonistas dos Canais de Cálcio/farmacologia , Metilação de DNA/efeitos dos fármacos , Éster Metílico do Ácido 3-Piridinacarboxílico, 1,4-Di-Hidro-2,6-Dimetil-5-Nitro-4-(2-(Trifluormetil)fenil)/farmacologia , Camundongos Endogâmicos C57BL , Antidepressivos/farmacologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Lipopolissacarídeos/farmacologia , Modelos Animais de DoençasRESUMO
Ca2+ release from the sarcoplasmic reticulum (SR) plays a central role in excitation-contraction coupling (ECC) in skeletal muscles. However, the mechanism by which activation of the voltage-sensors/dihydropyridine receptors (DHPRs) in the membrane of the transverse tubular system leads to activation of the Ca2+-release channels/ryanodine receptors (RyRs) in the SR is not fully understood. Recent observations showing that a very small Ca2+ leak through RyR1s in mammalian skeletal muscle can markedly raise the background [Ca2+] in the junctional space (JS) above the Ca2+ level in the bulk of the cytosol indicate that there is a diffusional barrier between the JS and the cytosol at large. Here, I use a mathematical model to explore the hypothesis that a sudden rise in Ca2+ leak through DHPR-coupled RyR1s, caused by reduced inhibition at the RyR1 Ca2+/Mg2+ inhibitory I1-sites when the associated DHPRs are activated, is sufficient to enable synchronized responses that trigger a regenerative rise of Ca2+ release that remains under voltage control. In this way, the characteristic response to Ca2+ of RyR channels is key not only for the Ca2+ release mechanism in cardiac muscle and other tissues, but also for the DHPR-dependent Ca2+ release in skeletal muscle.
Assuntos
Canais de Cálcio Tipo L , Cálcio , Músculo Esquelético , Canal de Liberação de Cálcio do Receptor de Rianodina , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Músculo Esquelético/metabolismo , Animais , Cálcio/metabolismo , Canais de Cálcio Tipo L/metabolismo , Retículo Sarcoplasmático/metabolismo , Sinalização do Cálcio/fisiologia , Acoplamento Excitação-Contração , Modelos Biológicos , HumanosRESUMO
Inadequate blood supply to the expanding adipose tissue (AT) is involved in the unhealthy AT remodeling and cardiometabolic consequences of obesity. Because of the pathophysiological role of upregulated mineralocorticoid receptor (MR) signaling in the complications of obesity, this study tested the vasoactive properties of finerenone, a nonsteroidal MR antagonist, in arteries of human AT. Arteries isolated from the visceral AT of obese subjects were studied in a wire myograph. Finerenone resulted in a concentration-dependent relaxation of arteries precontracted with either the thromboxane-A2 analog U46619, ET-1, or high-K+ solution; the steroidal MR antagonist potassium canrenoate, by contrast, did not relax arteries contracted with either U46619 or high-K+ solution. Finerenone-induced relaxation after precontraction with U46619 was greater in the arteries of obese versus nonobese subjects. Mechanistically, the vasorelaxing response to finerenone was not influenced by preincubation with the nitric oxide synthase inhibitor L-NAME or by endothelium removal. Interestingly, finerenone, like the dihydropyridine Ca2+-channel blocker nifedipine, relaxed arteries contracted with the L-type Ca2+-channel agonist Bay K8644. In conclusion, finerenone relaxes arteries of human visceral AT, likely through antagonism of L-type Ca2+ channels. This finding identifies a novel mechanism by which finerenone may improve AT perfusion, hence protecting against the cardiometabolic complications of obesity.
Assuntos
Canais de Cálcio Tipo L , Gordura Intra-Abdominal , Antagonistas de Receptores de Mineralocorticoides , Naftiridinas , Vasodilatação , Humanos , Canais de Cálcio Tipo L/metabolismo , Masculino , Naftiridinas/farmacologia , Gordura Intra-Abdominal/metabolismo , Gordura Intra-Abdominal/irrigação sanguínea , Gordura Intra-Abdominal/efeitos dos fármacos , Feminino , Pessoa de Meia-Idade , Vasodilatação/efeitos dos fármacos , Antagonistas de Receptores de Mineralocorticoides/farmacologia , Obesidade/metabolismo , Artérias/metabolismo , Artérias/efeitos dos fármacos , Adulto , Bloqueadores dos Canais de Cálcio/farmacologiaRESUMO
Leonurus japonicus Houtt is an exceptional medicinal herb used to treat obstetrical and gynecological diseases in traditional Chinese medicine, and it has significant effects on the treatment of dysmenorrhea and postpartum hemorrhage. This study investigated the effects of coumarins with diverse substituent groups from L. japonicus on isolated uterine smooth muscle and the preliminary mechanism of the most effective compound. Eight coumarins isolated from L. japonicus were assessed for their effects on the isolated uterine smooth muscle of nonpregnant rats in vitro. Coumarins 1 and 2 significantly promoted the contraction of rat uterine smooth muscle strips, whereas coumarins 3-5 showed remarkable relaxing effects against oxytocin (OT)-induced rat uterine smooth muscle contraction. Further mechanism investigations revealed that bergapten (coumarin 1) significantly increased the level of Ca2+ in uterine tissues by promoting extracellular Ca2+ influx and intracellular Ca2+ release, which were related to the activation of L-type Ca2+ channels and α-receptors. By contrast, osthole (coumarin 5), an α receptor antagonist, inhibited OT-induced uterine smooth muscle contraction by decreasing the level of Ca2+ in uterine tissues via inhibition of extracellular Ca2+ influx and intracellular Ca2+ release. This study demonstrates that the coumarins from L. japonicus are effective substances for regulating uterine smooth muscle contraction, but different coumarins with diverse substituent groups have different, even opposite effects. It can be inferred that coumarins are closely related to the efficacy of L. japonicus in the treatment of dysmenorrhea and postpartum hemorrhage.
Assuntos
Cálcio , Cumarínicos , Leonurus , Músculo Liso , Contração Uterina , Útero , Animais , Feminino , Cumarínicos/farmacologia , Cumarínicos/química , Leonurus/química , Ratos , Cálcio/metabolismo , Contração Uterina/efeitos dos fármacos , Útero/efeitos dos fármacos , Útero/metabolismo , Músculo Liso/efeitos dos fármacos , Músculo Liso/metabolismo , Contração Muscular/efeitos dos fármacos , Ratos Sprague-Dawley , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Canais de Cálcio Tipo L/metabolismo , Ocitocina/farmacologiaRESUMO
BACKGROUND: Atrial fibrillation (AF) is one of the most prevalent sustained cardiac arrhythmias, strongly associated with neutrophils. However, the underlying mechanism remain unclear. This study aims to explore the interaction between neutrophils and atrial myocytes in the pathogenesis of AF. METHODS: Patch-clamp was employed to record the action potential duration (APD) and ion channels in HL-1 cells. Flow cytometry was used to assess the differentiation of neutrophils. The mRNA and protein levels of CACNA1C, CACNA2D, and CACNB2 in HL-1 cells were detected. RESULTS: High-frequency electrical stimulation resulted in a shortening of the APD in HL-1 cells. Flow cytometry demonstrated that neutrophils were polarized into N1 phenotype when cultured with stimulated HL-1 cells medium. Compared to control neutrophils conditioned medium (CM), cocultured with TNF-α knockout neutrophils CM prolonged APD and the L-type Ca (2+) channel (LTCC) of HL-1 cells. Additionally, the expression of CACNA2D, CACNB2 and CACNA1C in HL-1 cells were upregulated. Compared with CACNA1C siRNA-transfected HL-1 cells treated with TNF-α siRNA-transfected neutrophils CM, the APD and LTCC of CACNA1C siRNA-transfected HL-1 cells were shortened in control N1 neutrophil CM. The APD and LTCC of control HL-1 cells were also shortened in control N1 neutrophil CM, but prolonged in TNF-α siRNA-transfected neutrophils CM. CONCLUSION: These findings suggest that neutrophils were polarized into N1 phenotype in AF, TNF-α released from N1 neutrophils contributes to the pathogenesis of AF, via decreasing the APD and LTCC in atrial myocytes through down-regulation of CACNA1C expression.
Assuntos
Potenciais de Ação , Fibrilação Atrial , Canais de Cálcio Tipo L , Átrios do Coração , Miócitos Cardíacos , Neutrófilos , Fibrilação Atrial/metabolismo , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/genética , Fibrilação Atrial/etiologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Neutrófilos/metabolismo , Animais , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/genética , Átrios do Coração/metabolismo , Átrios do Coração/patologia , Átrios do Coração/fisiopatologia , Linhagem Celular , Fator de Necrose Tumoral alfa/metabolismo , Técnicas de Cocultura , Comunicação Celular , Camundongos , Fenótipo , Humanos , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Familial hypokalemic periodic paralysis (HypoPP) is an uncommon genetic disorder characterized by recurrent episodes of muscle weakness and hypokalemia, typically starting in early adulthood. The existence of hyperthyroidism in the presence of HypoPP is more strongly associated with a diagnosis of thyrotoxic periodic paralysis (TPP), with most cases occurring in Asian males with pathogenic KCNJ2 or KCNJ18 variants and without a family history of the condition. This case is novel due to the combination of familial HypoPP and hyperthyroidism induced by Graves' disease, a rare occurrence especially in non-Asian populations. CASE PRESENTATION: A 40-year-old African American man presented with profound muscle weakness after consuming a high-salt meal. He had a significant family history of hyperthyroidism and hypokalemia. On examination, he showed profound weakness in all extremities. Laboratory tests confirmed hypokalemia and hyperthyroidism, and genetic testing identified a pathogenic variant in the CACNA1S gene (c.1583 G > A, p. R528H), with normal SCN4A, KCNJ2 and KCNJ18 sequencing. He was diagnosed with familial HypoPP and hyperthyroidism due to Graves' disease. He was started on PO methimazole 10 mg three times a day and PO acetazolamide 250 mg twice a day. He was advised to follow a low carbohydrate and low salt diet. CONCLUSIONS: This case highlights the importance of considering a genetic basis for HypoPP in patients with a family history of the condition, even when hyperthyroidism is present. The combination of familial HypoPP and Graves' disease is rare and emphasizes the need for careful genetic and clinical evaluation in similar cases. Management should focus on correcting hypokalemia, treating hyperthyroidism, and lifestyle modifications to prevent recurrence.
Assuntos
Hipertireoidismo , Paralisia Periódica Hipopotassêmica , Humanos , Masculino , Adulto , Paralisia Periódica Hipopotassêmica/genética , Paralisia Periódica Hipopotassêmica/etiologia , Paralisia Periódica Hipopotassêmica/diagnóstico , Hipertireoidismo/genética , Hipertireoidismo/complicações , Doença de Graves/genética , Doença de Graves/complicações , Canais de Cálcio Tipo L/genéticaRESUMO
Type 2 diabetes mellitus (T2DM) is a complex chronic disease characterized by decreased insulin secretion and the development of insulin resistance. Previous genome-wide association studies demonstrated that single-nucleotide polymorphisms (SNPs) present in genes coding for ion channels involved in insulin secretion increase the risk of developing this disease. We determined the association of 16 SNPs found in CACNA1D, KCNQ1, KCNJ11, and CACNA1E genes and the increased probability of developing T2DM. In this work, we performed a case-control study in 301 Mexican adults, including 201 cases with diabetes and 100 controls without diabetes. Our findings indicate a moderate association between T2DM and the C allele, and the C/C genotype of rs312480 within CACNA1D. The CAG haplotype surprisingly showed a protective effect, whereas the CAC and CGG haplotypes have a strong association with T2DM. The C allele and C/C genotype of rs5219 were significantly associated with diabetes. Also, an association was observed between diabetes and the A allele and the A/A genotype of rs3753737 and rs175338 in CACNA1E. The TGG and CGA haplotypes were also found to be significantly associated. The findings of this study indicate that the SNPs examined could serve as a potential diagnostic tool and contribute to the susceptibility of the Mexican population to this disease.
Assuntos
Canais de Cálcio Tipo L , Diabetes Mellitus Tipo 2 , Predisposição Genética para Doença , Canal de Potássio KCNQ1 , Polimorfismo de Nucleotídeo Único , Canais de Potássio Corretores do Fluxo de Internalização , Humanos , Diabetes Mellitus Tipo 2/genética , Canais de Cálcio Tipo L/genética , Canal de Potássio KCNQ1/genética , Feminino , Masculino , Canais de Potássio Corretores do Fluxo de Internalização/genética , Pessoa de Meia-Idade , Estudos de Casos e Controles , Adulto , Haplótipos , Canais de Cálcio Tipo R/genética , Alelos , México , Idoso , Estudos de Associação Genética , Genótipo , Frequência do Gene , Proteínas de Transporte de CátionsRESUMO
Variants in KCNMA1, encoding the voltage- and calcium-activated K+ (BK) channel, are associated with human neurological disease. The effects of gain-of-function (GOF) and loss-of-function (LOF) variants have been predominantly studied on BK channel currents evoked under steady-state voltage and Ca2+ conditions. However, in their physiological context, BK channels exist in partnership with voltage-gated Ca2+ channels and respond to dynamic changes in intracellular Ca2+ (Ca2+i). In this study, an L-type voltage-gated Ca2+ channel present in the brain, CaV1.2, was co-expressed with wild type and mutant BK channels containing GOF (D434G, N999S) and LOF (H444Q, D965V) patient-associated variants in HEK-293T cells. Whole-cell BK currents were recorded under CaV1.2 activation using buffering conditions that restrict Ca2+i to nano- or micro-domains. Both conditions permitted wild type BK current activation in response to CaV1.2 Ca2+ influx, but differences in behavior between wild type and mutant BK channels were reduced compared to prior studies in clamped Ca2+i. Only the N999S mutation produced an increase in BK current in both micro- and nano-domains using square voltage commands and was also detectable in BK current evoked by a neuronal action potential within a microdomain. These data corroborate the GOF effect of N999S on BK channel activity under dynamic voltage and Ca2+ stimuli, consistent with its pathogenicity in neurological disease. However, the patient-associated mutations D434G, H444Q, and D965V did not exhibit significant effects on BK current under CaV1.2-mediated Ca2+ influx, in contrast with prior steady-state protocols. These results demonstrate a differential potential for KCNMA1 variant pathogenicity compared under diverse voltage and Ca2+ conditions.
Assuntos
Canais de Cálcio Tipo L , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta , Humanos , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/genética , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Células HEK293 , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/genética , Canalopatias/genética , Canalopatias/metabolismo , Cálcio/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Canais de Potássio Ativados por Cálcio de Condutância Alta/genética , MutaçãoRESUMO
Background and Objective. This study addresses the Force-Frequency relationship, a fundamental characteristic of cardiac muscle influenced byß1-adrenergic stimulation. This relationship reveals that heart rate (HR) changes at the sinoatrial node lead to alterations in ventricular cell contractility, increasing the force and decreasing relaxation time for higher beat rates. Traditional models lacking this relationship offer an incomplete physiological depiction, impacting the interpretation of in silico experiment results. To improve this, we propose a new mathematical model for ventricular myocytes, named 'Feed Forward Modeling' (FFM).Methods. FFM adjusts model parameters like channel conductance and Ca2+pump affinity according to stimulation frequency, in contrast to fixed parameter values. An empirical sigmoid curve guided the adaptation of each parameter, integrated into a rabbit ventricular cell electromechanical model. Model validation was achieved by comparing simulated data with experimental current-voltage (I-V) curves for L-type Calcium and slow Potassium currents.Results. FFM-enhanced simulations align more closely with physiological behaviors, accurately reflecting inotropic and lusitropic responses. For instance, action potential duration at 90% repolarization (APD90) decreased from 206 ms at 1 Hz to 173 ms at 4 Hz using FFM, contrary to the conventional model, where APD90 increased, limiting high-frequency heartbeats. Peak force also showed an increase with FFM, from 8.5 mN mm-2at 1 Hz to 11.9 mN mm-2at 4 Hz, while it barely changed without FFM. Relaxation time at 50% of maximum force (t50) similarly improved, dropping from 114 ms at 1 Hz to 75.9 ms at 4 Hz with FFM, a change not observed without the model.Conclusion. The FFM approach offers computational efficiency, bypassing the need to model all beta-adrenergic pathways, thus facilitating large-scale simulations. The study recommends that frequency change experiments include fractional dosing of isoproterenol to better replicate heart conditionsin vivo.
Assuntos
Potenciais de Ação , Simulação por Computador , Ventrículos do Coração , Contração Miocárdica , Miócitos Cardíacos , Coelhos , Animais , Miócitos Cardíacos/fisiologia , Contração Miocárdica/fisiologia , Modelos Cardiovasculares , Frequência Cardíaca/fisiologia , Cálcio/metabolismo , Canais de Cálcio Tipo L/metabolismo , Nó Sinoatrial/fisiologia , Modelos TeóricosRESUMO
Aging is a physiological process that is still poorly understood, especially with respect to effects on the brain. There are open questions about aging that are difficult to answer with an experimental approach. Underlying challenges include the difficulty of recording in vivo single cell and network activity simultaneously with submillisecond resolution, and brain compensatory mechanisms triggered by genetic, pharmacologic, or behavioral manipulations. Mathematical modeling can help address some of these questions by allowing us to fix parameters that cannot be controlled experimentally and investigate neural activity under different conditions. We present a biophysical minimal model of CA1 pyramidal cells (PCs) based on general expressions for transmembrane ion transport derived from thermodynamical principles. The model allows directly varying the contribution of ion channels by changing their number. By analyzing the dynamics of the model, we find parameter ranges that reproduce the variability in electrical activity seen in PCs. In addition, increasing the L-type Ca2+ channel expression in the model reproduces age-related changes in electrical activity that are qualitatively and quantitatively similar to those observed in PCs from aged animals. We also make predictions about age-related changes in PC bursting activity that, to our knowledge, have not been reported previously. We conclude that the model's biophysical nature, flexibility, and computational simplicity make it a potentially powerful complement to experimental studies of aging.
Assuntos
Envelhecimento , Região CA1 Hipocampal , Células Piramidais , Células Piramidais/metabolismo , Células Piramidais/fisiologia , Animais , Envelhecimento/fisiologia , Região CA1 Hipocampal/fisiologia , Região CA1 Hipocampal/citologia , Região CA1 Hipocampal/metabolismo , Modelos Neurológicos , Potenciais de Ação/fisiologia , Canais de Cálcio Tipo L/metabolismo , Fenômenos BiofísicosRESUMO
OBJECTIVE: To explore the impact of CACNA1C rs58619945 genotype on the cortical thickness of attentional networks in patients with Bipolar 1 disorder type (BD-â ). METHODS: From August 2013 and August 2019, a total of 155 BD-â patients were recruited from the outpatient and inpatient Departments of the Affiliated Brain Hospital of Guangzhou Medical University, along with 82 healthy controls (HC) from the community and university. Genotype for the CACNA1C rs58619945 locus was determined for all BD-I patients and HC subjects, followed by 3.0 T magnetic resonance imaging scans to measure the cortical thickness in the alert, orienting, and executive control subnetworks. General linear models (GLMs) were used to evaluate the impact of CACNA1C rs58619945 on the cortical thickness of attentional networks. Concurrently, attentional dimension functions were assessed using repeatable battery for the assessment of neuropsychological status (RBANS) and Cambridge neuropsychological test automated battery rapid visual information processing (CANTAB RVP) test. RESULTS: Compared with the HC group, the BD-I patients had shown reduced thickness in bilateral prefrontal cortex, bilateral posterior cingulate cortex, and bilateral superior temporal cortex. A significant interaction between the CACNA1C genotype and the cortical thickness of right prefrontal cortex, right posterior parietal cortex and right superior temporal cortex was noted. Partial correlation analysis has demonstrated a significant correlation between CANTAB RVP and RBANS attention indices and cortical thickness in the right prefrontal cortex, right posterior cingulate cortex, and right superior temporal cortex predominantly among carriers of the BD-I G allele. CONCLUSION: The G allele of CACNA1C rs58619945 is associated with cortical thickness of the right prefrontal cortex, right posterior cingulate cortex, and right superior temporal cortex in BD-â , which are part of the alerting and orienting network.
Assuntos
Atenção , Transtorno Bipolar , Canais de Cálcio Tipo L , Genótipo , Humanos , Adulto , Transtorno Bipolar/genética , Transtorno Bipolar/fisiopatologia , Transtorno Bipolar/diagnóstico por imagem , Masculino , Feminino , Canais de Cálcio Tipo L/genética , Imageamento por Ressonância Magnética , Córtex Cerebral/diagnóstico por imagem , Polimorfismo de Nucleotídeo Único , Pessoa de Meia-Idade , Adulto JovemRESUMO
Most neurons are not replaced after injury and thus possess robust intrinsic mechanisms for repair after damage. Axon injury triggers a calcium wave, and calcium and cAMP can augment axon regeneration. In comparison to axon regeneration, dendrite regeneration is poorly understood. To test whether calcium and cAMP might also be involved in dendrite injury signaling, we tracked the responses of Drosophila dendritic arborization neurons to laser severing of axons and dendrites. We found that calcium and subsequently cAMP accumulate in the cell body after both dendrite and axon injury. Two voltage-gated calcium channels (VGCCs), L-Type and T-Type, are required for the calcium influx in response to dendrite injury and play a role in rapid initiation of dendrite regeneration. The AC8 family adenylyl cyclase, Ac78C, is required for cAMP production after dendrite injury and timely initiation of regeneration. Injury-induced cAMP production is sensitive to VGCC reduction, placing calcium upstream of cAMP generation. We propose that two VGCCs initiate global calcium influx in response to dendrite injury followed by production of cAMP by Ac78C. This signaling pathway promotes timely initiation of dendrite regrowth several hours after dendrite damage.
Assuntos
Adenilil Ciclases , Canais de Cálcio Tipo L , Cálcio , AMP Cíclico , Dendritos , Animais , Adenilil Ciclases/metabolismo , Adenilil Ciclases/genética , Axônios/metabolismo , Axônios/fisiologia , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Canais de Cálcio/genética , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/genética , Canais de Cálcio Tipo T/metabolismo , Canais de Cálcio Tipo T/genética , Sinalização do Cálcio/genética , AMP Cíclico/metabolismo , Dendritos/metabolismo , Drosophila/genética , Drosophila melanogaster/genética , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Regeneração Nervosa/fisiologia , Regeneração Nervosa/genética , Neurônios/metabolismo , Regeneração/genética , Regeneração/fisiologia , Transdução de SinaisRESUMO
Predicting drug toxicity is a critical aspect of ensuring patient safety during the drug design process. Although conventional machine learning techniques have shown some success in this field, the scarcity of annotated toxicity data poses a significant challenge in enhancing models' performance. In this study, we explore the potential of leveraging large unlabeled small molecule data sets using semisupervised learning to improve drug cardiotoxicity predictive performance across three cardiac ion channel targets: the voltage-gated potassium channel (hERG), the voltage-gated sodium channel (Nav1.5), and the voltage-gated calcium channel (Cav1.2). We extensively mined the ChEMBL database, comprising approximately 2 million small molecules, and then employed semisupervised learning to construct robust classification models for this purpose. We achieved a performance boost on highly diverse (i.e., structurally dissimilar) test data sets across all three targets. Using our built models, we screened the whole ChEMBL database and a large set of FDA-approved drugs, identifying several compounds with potential cardiac ion channel activity. To ensure broad accessibility and usability for both technical and nontechnical users, we developed a cross-platform graphical user interface that allows users to make predictions and gain insights into the cardiotoxicity of drugs and other small molecules. The software is made available as open source under the permissive MIT license at https://github.com/issararab/CToxPred2.
Assuntos
Canais de Cálcio Tipo L , Mineração de Dados , Canal de Sódio Disparado por Voltagem NAV1.5 , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/química , Humanos , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.5/química , Aprendizado de Máquina Supervisionado , Bibliotecas de Moléculas Pequenas/química , CardiotoxicidadeRESUMO
Over half of spinal cord injury (SCI) patients develop opioid-resistant chronic neuropathic pain. Safer alternatives to opioids for treatment of neuropathic pain are gabapentinoids (e.g., pregabalin and gabapentin). Clinically, gabapentinoids appear to amplify opioid effects, increasing analgesia and overdose-related adverse outcomes, but in vitro proof of this amplification and its mechanism are lacking. We previously showed that after SCI, sensitivity to opioids is reduced by fourfold to sixfold in rat sensory neurons. Here, we demonstrate that after injury, gabapentinoids restore normal sensitivity of opioid inhibition of cyclic AMP (cAMP) generation, while reducing nociceptor hyperexcitability by inhibiting voltage-gated calcium channels (VGCCs). Increasing intracellular Ca2+ or activation of L-type VGCCs (L-VGCCs) suffices to mimic SCI effects on opioid sensitivity, in a manner dependent on the activity of the Raf1 proto-oncogene, serine/threonine-protein kinase C-Raf, but independent of neuronal depolarization. Together, our results provide a mechanism for potentiation of opioid effects by gabapentinoids after injury, via reduction of calcium influx through L-VGCCs, and suggest that other inhibitors targeting these channels may similarly enhance opioid treatment of neuropathic pain.
Assuntos
Analgésicos Opioides , AMP Cíclico , Gabapentina , Neuralgia , Transdução de Sinais , Traumatismos da Medula Espinal , Animais , Neuralgia/tratamento farmacológico , Neuralgia/metabolismo , AMP Cíclico/metabolismo , Ratos , Traumatismos da Medula Espinal/tratamento farmacológico , Traumatismos da Medula Espinal/metabolismo , Analgésicos Opioides/farmacologia , Gabapentina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Ratos Sprague-Dawley , Masculino , Canais de Cálcio Tipo L/metabolismo , Cálcio/metabolismo , Pregabalina/farmacologia , Pregabalina/uso terapêutico , Sinergismo Farmacológico , Células Receptoras Sensoriais/metabolismo , Células Receptoras Sensoriais/efeitos dos fármacosRESUMO
Skeletal muscle contractions are initiated by action potentials, which are sensed by the voltage-gated calcium channel (CaV1.1) and are conformationally coupled to calcium release from intracellular stores. Notably, CaV1.1 contains four separate voltage-sensing domains (VSDs), which activate channel gating and excitation-contraction (EC-) coupling at different voltages and with distinct kinetics. Here we show that a single VSD of CaV1.1 controls skeletal muscle EC-coupling. Whereas mutations in VSDs I, II and IV affect the current properties but not EC-coupling, only mutations in VSD III alter the voltage-dependence of depolarization-induced calcium release. Molecular dynamics simulations reveal comprehensive, non-canonical state transitions of VSD III in response to membrane depolarization. Identifying the voltage sensor that activates EC-coupling and detecting its unique conformational changes opens the door to unraveling the downstream events linking VSD III motion to the opening of the calcium release channel, and thus resolving the signal transduction mechanism of skeletal muscle EC-coupling.
Assuntos
Canais de Cálcio Tipo L , Cálcio , Acoplamento Excitação-Contração , Simulação de Dinâmica Molecular , Músculo Esquelético , Domínios Proteicos , Humanos , Potenciais de Ação/fisiologia , Cálcio/metabolismo , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/genética , Canais de Cálcio Tipo L/química , Células HEK293 , Ativação do Canal Iônico , Contração Muscular/fisiologia , Músculo Esquelético/metabolismo , MutaçãoRESUMO
Vasodilation in response to low oxygen (O2) tension (hypoxic vasodilation) is an essential homeostatic response of systemic arteries that facilitates O2 supply to tissues according to demand. However, how blood vessels react to O2 deficiency is not well understood. A common belief is that arterial myocytes are O2-sensitive. Supporting this concept, it has been shown that the activity of myocyte L-type Ca2+channels, the main ion channels responsible for vascular contractility, is reversibly inhibited by hypoxia, although the underlying molecular mechanisms have remained elusive. Here, we show that genetic or pharmacological disruption of mitochondrial electron transport selectively abolishes O2 modulation of Ca2+ channels and hypoxic vasodilation. Mitochondria function as O2 sensors and effectors that signal myocyte Ca2+ channels due to constitutive Hif1α-mediated expression of specific electron transport subunit isoforms. These findings reveal the acute O2-sensing mechanisms of vascular cells and may guide new developments in vascular pharmacology.
Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia , Mitocôndrias , Oxigênio , Vasodilatação , Animais , Mitocôndrias/metabolismo , Oxigênio/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Camundongos , Transdução de Sinais , Masculino , Hipóxia/metabolismo , Camundongos Endogâmicos C57BL , Artérias/metabolismo , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Tipo L/genética , Camundongos Knockout , Transporte de Elétrons , Canais de Cálcio/metabolismo , Canais de Cálcio/genéticaRESUMO
Due to the widespread use of methamphetamine (METH) among reproductive-aged women, the effects of intrauterine exposure to METH need to be investigated, as previous studies on this topic have been limited. The goal of this study is to examine the influence of two regulatory genes (miRNA-151-3p and CACNA1C) on the intrauterine life of mice exposed to METH. Pregnant mice received doses of 2 and 5 mg/kg of METH and saline from day 10 of pregnancy until the end. Their offspring were then evaluated for miRNA-151-3p and CACNA1C gene expression levels using real-time PCR. The findings indicated that exposure to METH reduced the expression levels of both miRNA-151-3p and CACNA1C genes in offspring compared to the control group (p≤0.001). In conclusion, intrauterine exposure to METH leads to a decrease in expression levels of both miRNA-151-3p and CACNA1C genes, potentially disrupting regulatory pathways involving these genes and having an impact on male reproductive health.
Assuntos
Canais de Cálcio Tipo L , Regulação para Baixo , Metanfetamina , MicroRNAs , Efeitos Tardios da Exposição Pré-Natal , Testículo , Animais , Metanfetamina/toxicidade , MicroRNAs/genética , MicroRNAs/metabolismo , Feminino , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/genética , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Canais de Cálcio Tipo L/genética , Canais de Cálcio Tipo L/metabolismo , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Testículo/efeitos dos fármacos , Testículo/metabolismo , Ratos , CamundongosRESUMO
AIMS: To explore the role of voltage-gated calcium channels (VGCC) in 5-HT2A/2C receptor agonist 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride's improvement of spinal cord injury (SCI) induced detrusor sphincter dyssynergia and the expressions of the 5-hydroxy tryptamine (5-HT) 2A receptors and VGCCs in lumbosacral cord after SCI. METHODS: Female Sprague-Dawley rats were randomized into normal control group and SCI group (N = 15 each). Cystometrogram (CMG), simultaneous CMG, and external urethral sphincter electromyography (EUS-EMG) were conducted in all groups under urethane anesthesia. Drugs were administered intrathecally during CMG and EUS-EMG. Rats were euthanized and L6-S1 spinal cord were acquired for immunofluorescence. RESULTS: In SCI rats, intrathecal administration of 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride or L-type VGCC blocker, nifedipine, could significantly increase voiding volume, voiding efficiency, and the number of high-frequency oscillations. They could also prolong EUS bursting activity duration on EUS-EMG. Moreover, the effect of 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride can be eliminated with the combined administration of L-type VGCC agonist, (±)-Bay K 8644. No significant differences were observed in CMG after intrathecal administration of T-type VGCC blocker TTA-P2. Additionally, immunofluorescence of the lumbosacral cord in control and SCI rats showed that the 5-HT2A receptor and Cav1.2 immunolabeling-positive neurons in the anterior horn of the lumbosacral cord were increased in SCI rats. CONCLUSIONS: Our study demonstrated that 5-HT2A/2C agonist 2,5-dimethoxy-4-iodophenyl-2-aminopropane hydrochloride may improve SCI-induced DSD by inhibiting the L-type voltage-gated calcium channel in lumbosacral cord motoneurons.