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1.
Gene ; 722: 144101, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31479714

RESUMO

The catadromous species, eels, invariably exposed to variable Ca2+ concentrations circumstance i.e., lagoon or ocean. They need to maintain Ca2+ homeostasis by exchanging Ca2+ under different culture conditions. To understand the effects of environmental Ca2+ to fish, three types of genes coding for voltage-dependent L-type calcium channels (cacnb1, 2, 3) were cloned by screening an A. marmorata cDNA library. Tissue distribution analysis of Western blot showed that Cacnb1, 2, 3 had a significantly high expression in gill; while mRNA results showed the expressions of cacnb1 and cacnb3 were predominated in skin tissue but only cacnb2 was expressed in intestine. Serum osmolality and Ca2+ concentrations of A.marmorata were increased in a high calcium environment while reduced in a low calcium environment within 7 days; however, they were not significantly different among Ca2+ treatments after the eels were acclimated for 7 days. We also examined the influence of ambient Ca2+ levels on cacnbs expression of eels. With the increasing of exposure time, mRNA and protein expressions of cacnb1 were up-regulated in high level of Ca2+ (10 mM) and down-regulated in deficient Ca2+ (0 mM) compared to the control Ca2+ (2 mM). However, the opposite results were observed in cacnb2 and cacnb3. Notably, the cacnb2 expression was not significant different among Ca2+ treatments on day 7. Our study provided the insightful evidence that cacnbs play important roles in maintaining Ca2+ homeostasis of fish.


Assuntos
Anguilla/metabolismo , Canais de Cálcio Tipo L/metabolismo , Cálcio/fisiologia , Aclimatação , Anguilla/sangue , Anguilla/genética , Animais , Cálcio/sangue , Canais de Cálcio Tipo L/química , Canais de Cálcio Tipo L/genética , Clonagem Molecular , Brânquias/metabolismo , Concentração Osmolar , RNA Mensageiro/metabolismo , Distribuição Tecidual
2.
Adv Exp Med Biol ; 1131: 281-320, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31646515

RESUMO

In mammalian cardiomyocytes, Ca2+ influx through L-type voltage-gated Ca2+ channels (VGCCs) is amplified by release of Ca2+ via type 2 ryanodine receptors (RyR2) in the sarcoplasmic reticulum (SR): a process termed Ca2+-induced Ca2+-release (CICR). In mammalian skeletal muscles, VGCCs play a distinct role as voltage-sensors, physically interacting with RyR1 channels to initiate Ca2+ release in a mechanism termed depolarisation-induced Ca2+-release (DICR). In the current study, we surveyed the genomes of animals and their close relatives, to explore the evolutionary history of genes encoding three proteins pivotal for ECC: L-type VGCCs; RyRs; and a protein family that anchors intracellular organelles to plasma membranes, namely junctophilins (JPHs). In agreement with earlier studies, we find that non-vertebrate eukaryotes either lack VGCCs, RyRs and JPHs; or contain a single homologue of each protein. Furthermore, the molecular features of these proteins thought to be essential for DICR are only detectable within vertebrates and not in any other taxonomic group. Consistent with earlier physiological and ultrastructural observations, this suggests that CICR is the most basal form of ECC and that DICR is a vertebrate innovation. This development was accompanied by the appearance of multiple homologues of RyRs, VGCCs and junctophilins in vertebrates, thought to have arisen by 'whole genome replication' mechanisms. Subsequent gene duplications and losses have resulted in distinct assemblies of ECC components in different vertebrate clades, with striking examples being the apparent absence of RyR2 from amphibians, and additional duplication events for all three ECC proteins in teleost fish. This is consistent with teleosts possessing the most derived mode of DICR, with their Cav1.1 VGCCs completely lacking in Ca2+ channel activity.


Assuntos
Canais de Cálcio Tipo L , Evolução Molecular , Acoplamento Excitação-Contração , Canal de Liberação de Cálcio do Receptor de Rianodina , Animais , Canais de Cálcio Tipo L/metabolismo , Acoplamento Excitação-Contração/genética , Peixes/genética , Peixes/metabolismo , Genoma/genética , Músculo Esquelético/fisiologia , Miócitos Cardíacos/fisiologia , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/fisiologia
3.
Adv Exp Med Biol ; 1185: 233-238, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31884617

RESUMO

The specific association of Leber congenital amaurosis (LCA) or early-onset severe retinal dystrophy (LCA-like) with sensorineural hearing loss (SHL) is uncommon. Recently, we ascribed some of these distinctive associations to dominant and de novo mutations in the ß-tubulin 4B isotype-encoding gene (TUBB4B), providing a link between a sensorineural disease and anomalies in microtubules behavior. Here, we report 12 sporadic cases with LCA/SHL or LCA-like/SHL and no TUBB4B mutation. Trio-based whole exome sequencing (WES) identified disease-causing mutations in 5/12 cases. Four out of five carried biallelic mutations in PEX1 (1/4) or PEX6 (3/4), involved in peroxisome biogenesis disorders from Zellweger syndrome characterized by severe neurologic and neurosensory dysfunctions, craniofacial abnormalities, and liver dysfunction to Heimler syndrome associating SHL, enamel hypoplasia of the secondary dentition, nail abnormalities, and occasional retinal disease. Upon reexamination, the index case carrying PEX1 mutations, a 4-year-old girl, presented additional symptoms consistent with Zellweger syndrome. Reexamination of individuals with PEX6 mutations (1/3 unavailable) revealed normal nails but enamel hypoplasia affecting one primary teeth in a 4-year-old girl and severe enamel hypoplasia of primary teeth hidden by dental prosthesis in a 50-year-old male, describing a novel PEX6-associated disease of the Zellweger/Heimler spectrum. Finally, hemizygosity for a CACNA1F mutation was identified in an 18-year-old male addressed for LCA/SHL, redirecting the retinal diagnosis to congenital stationary night blindness (CSNB2A). Consistent with the pure CSNB2A retinal involvement, SHL was ascribed to biallelic mutations in another gene, STRC, involved in nonprogressive DFNB16 deafness.


Assuntos
Perda Auditiva Neurossensorial/genética , Amaurose Congênita de Leber/genética , Distrofias Retinianas/genética , ATPases Associadas a Diversas Atividades Celulares/genética , Adolescente , Canais de Cálcio Tipo L/genética , Pré-Escolar , Análise Mutacional de DNA , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Mutação , Unhas Malformadas , Linhagem
4.
Sheng Li Xue Bao ; 71(6): 863-873, 2019 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-31879742

RESUMO

The aim of this study was to investigate the inhibitory effect and the underlying mechanism of ethacrynic acid (EA) on the contraction in mice. BL-420S force measuring system was used to measure the tension of mouse tracheal rings. The whole cell patch clamp technique was utilized to record the channel currents of airway smooth muscle (ASM) cells. The calcium imaging system was used to determine the intracellular Ca2+ concentration ([Ca2+]i) in ASM cells. The results showed that EA significantly inhibited the high K+ (80 mmol/L) and acetylcholine (ACh, 100 µmol/L)-induced contraction of mouse tracheal rings in a dose-dependent manner. The maximal relaxation percentages were (97.02 ± 1.56)% and (85.21 ± 0.03)%, and the median effective concentrations were (40.28 ± 2.20) µmol/L and (56.22 ± 7.62) µmol/L, respectively. EA decreased the K+ and ACh-induced elevation of [Ca2+]i from 0.40 ± 0.04 to 0.16 ± 0.01 and from 0.50 ± 0.01 to 0.39 ± 0.01, respectively. In addition, EA inhibited L-type voltage-dependent calcium channel (LVDCC) and store-operated calcium channel (SOCC) currents in ASM cells, and Ca2+ influx. Moreover, EA decreased the resistance of the respiratory system (Rrs) in vivo in mice. These results indicated that EA inhibits LVDCC and SOCC, which results in termination of Ca2+ influx and decreases of [Ca2+]i, leading to relaxation of ASM. Taken together, EA might be a potential bronchodilator.


Assuntos
Ácido Etacrínico , Contração Muscular , Músculo Liso , Sistema Respiratório , Animais , Cálcio/metabolismo , Canais de Cálcio Tipo L , Inibidores Enzimáticos/farmacologia , Ácido Etacrínico/farmacologia , Camundongos , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Sistema Respiratório/citologia , Sistema Respiratório/efeitos dos fármacos
5.
Sheng Li Xue Bao ; 71(5): 717-724, 2019 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-31646325

RESUMO

The aim of this study was to investigate the effect of interleukin 6 (IL-6) on the contraction of colon longitudinal muscle strips in rats with acute pancreatitis (AP) and its underlying mechanism. Rat AP model was established by combined injection (i. p.) of ceruletide and lipopolysaccharide. The effect of IL-6 on spontaneous contraction of longitudinal smooth muscle strips of rat colon was observed by biological function experiment system. The level of serum IL-6 was detected by ELISA, the expression and distribution of IL-6 in colon were observed by histochemical staining, and the effect of IL-6 on L-type calcium channel in colon smooth muscle cells was observed by whole cell patch clamp technique. The results showed that, compared with the control group, AP group exhibited reduced contractile amplitude and longer contraction cycle of colon smooth muscle strips. IL-6 prolonged the contraction cycle of colon smooth muscle strips, but did not affect their spontaneous contraction amplitude. Serum IL-6 concentration in AP group was significantly higher than that in control group (P > 0.05). IL-6 was diffusely distributed in the colon of the control group, but the expression of IL-6 was significantly up-regulated in the colon gland, mucosa and submucosa of the AP group. IL-6 significantly decreased the peak current density of L-type calcium channel in rat colon smooth muscle cells. These results suggest that the colon motility of AP rats is weakened, and the mechanism may be that up-regulated IL-6 inactivates L-type voltage-dependent calcium channels, and then inhibits the contraction of colon longitudinal smooth muscle.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Interleucina-6/metabolismo , Contração Muscular , Músculo Liso/fisiopatologia , Pancreatite/fisiopatologia , Animais , Colo , Ratos
6.
Life Sci ; 238: 116953, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31626793

RESUMO

AIMS: This study focused on investigating whether NS8593 reverses airway smooth muscle (ASM) contraction and the underlying mechanism. MAIN METHODS: ASM contraction in mouse tracheal rings and lung slices was measured. Currents mediated by voltage dependent Ca2+ channels (VDCCs) and ACH-activated channels were measured using the whole-cell patch-clamp technique in single tracheal smooth muscle cells (TSMCs). Intracellular Ca2+ level and cell length were measured using an LSM 700 laser confocal microscope and a Zen 2010 software. Mouse respiratory system resistance (Rrs) was assessed using a FlexiVent FX system. KEY FINDINGS: High K+ (80 mM K+) and ACH induced ASM contraction in mouse tracheal rings and lung slices, which was partially relaxed by nifedipine (blocker of L-type VDCCs, LVDCCs), YM-58483 (blocker of store-operated Ca2+ entry (SOCE), transient receptor potential C3 (TRPC3) and TRPC5 channels), respectively. However, the contraction was completely reversed by NS8593, whereas, slightly relaxed by formoterol. ACH activated inward currents, which displayed linear and reversed around 0 mV, indicating the currents were mediated by non-selective cation channels (NSCCs). Moreover, these currents were blocked by YM-58483. In addition, such currents were abolished by NS8593, implicating that NS8593 inhibits the same channels. Besides, NS8593 inhibited increases of intracellular Ca2+ and the associated cell shortening. Finally, NS8593 inhibited ACH-induced increases of mouse respirator system resistance (Rrs). SIGNIFICANCE: Our results indicate that NS8593 inhibits LVDCCs and NSCCs, resulting in decreases of intracellular Ca2+ and then leading to ASM relaxation. These data suggest that NS8593 might be a new bronchodilator.


Assuntos
1-Naftilamina/análogos & derivados , Asma/tratamento farmacológico , Canais de Cálcio Tipo L/química , Cálcio/metabolismo , Contração Muscular/efeitos dos fármacos , Relaxamento Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , 1-Naftilamina/farmacologia , Animais , Antialérgicos/farmacologia , Asma/induzido quimicamente , Asma/patologia , Canais de Cálcio Tipo L/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Músculo Liso/metabolismo , Músculo Liso/patologia , Ovalbumina/toxicidade
7.
Rev Cardiovasc Med ; 20(3): 139-151, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31601088

RESUMO

Effective therapy of hypertension represents a key strategy for reducing the burden of cardiovascular disease and its associated mortality. The significance of voltage dependent L-type Ca²âº channels to Ca²âº influx, and of their regulatory mechanisms in the development of heart disease, is well established. A wide variety of L-type Ca²âº channel inhibitors and Ca²âº antagonists have been found to be beneficial not only in the treatment of hypertension, but also in myocardial infarction and heart failure. Over the past two decades, another class of Ca²âº channel - the voltage independent store-operated Ca²âº channel - has been implicated in the regulation and fine tuning of Ca²âº entry in both cardiac and smooth muscle cells. Store-operated Ca²âº channels are activated by the depletion of Ca²âº stores within the endoplasmic/sarcoplasmic reticulum, or by low levels of cytosolic Ca²âº, thereby facilitating agonist-induced Ca²âº influx. Store-operated Ca²âº entry through this pivotal pathway involves both stromal interaction molecule (STIM) and Orai channels. Different degrees of changes in these proteins are considered to promote Ca²âº entry and hence contribute to the pathogenesis of cardiovascular dysfunction. Several blockers of store-operated Ca²âº channels acting at the level of both STIM and Orai channels have been shown to depress Ca²âº influx and lower blood pressure. However, their specificity, safety, and clinical significance remain to be established. Thus, there is an ongoing challenge in the development of selective inhibitors of store-operated Ca²âº channels that act in vascular smooth muscles for the improved treatment of hypertension.


Assuntos
Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/uso terapêutico , Canais de Cálcio Ativados pela Liberação de Cálcio/antagonistas & inibidores , Hipertensão/tratamento farmacológico , Músculo Liso Vascular/efeitos dos fármacos , Moléculas de Interação Estromal/antagonistas & inibidores , Vasodilatadores/uso terapêutico , Animais , Anti-Hipertensivos/efeitos adversos , Bloqueadores dos Canais de Cálcio/efeitos adversos , Canais de Cálcio Tipo L/efeitos dos fármacos , Canais de Cálcio Tipo L/metabolismo , Canais de Cálcio Ativados pela Liberação de Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Humanos , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/fisiopatologia , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Moléculas de Interação Estromal/metabolismo , Resultado do Tratamento , Vasodilatadores/efeitos adversos
8.
BMC Med Genet ; 20(1): 157, 2019 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-31510946

RESUMO

BACKGROUND: X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disorder caused by germline mutations in the Bruton tyrosine kinase (BTK) gene on X chromosome. These mutations disturb B-cell development, decrease immunoglobulin levels, increase susceptibility to infection or neoplasms, and increase the risk of developing colorectal cancer (CRC). For occasional cases of CRC have been reported in XLA patients, low levels of B lymphocytes and immunoglobulins induced by congenital immune disorder make them more susceptible to drug-related toxicities (DRT). Therefore, gene sequencing, therapeutic drug monitoring and any possible measurement to predict DRT should be considered before determining the course of chemotherapy for XLA patients with CRC. CASE PRESENTATION: In this study, we reported a 21-year-old male who developed metastatic CRC in the context of XLA. Since the whole exome sequencing and therapeutic drug monitoring did not reveal any predictive markers of DRT, we applied standard first-line chemotherapy to the patient. However, progressive disease occurred after the fifth treatment cycle. Therefore, the administration of oxaliplatin was changed to irinotecan as second-line therapy. After that, the patient firstly suffered from severe hypocalcemia and eventually died due to metastatic CRC after the eighth treatment cycle. The overall survival time was 7.5 months. CONCLUSIONS: This study reported the first written record of a Chinese XLA patient with metastatic CRC and severe hypocalcemia. Whole exome sequencing and bioinformatic analysis indicated the somatic mutations in ABCA6, C6 and PAX3 genes might contribute to the early-onset and metastasis CRC. Besides, a number of germline mutations in genes related to calcium metabolism (CACNA2D4, CD36, etc.) and the administration of irinotecan were speculated to be the causes of severe hypocalcemia. We therefore suggested that in order to avoid severe DRT, clinicians should take genetic background and therapeutic drug monitoring into consideration while planning chemotherapy treatment for XLA patients with CRC.


Assuntos
Tirosina Quinase da Agamaglobulinemia/genética , Agamaglobulinemia/genética , Neoplasias Colorretais/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Predisposição Genética para Doença/genética , Hipocalcemia/complicações , Irinotecano/administração & dosagem , Transportadores de Cassetes de Ligação de ATP/genética , Adulto , Agamaglobulinemia/diagnóstico por imagem , Grupo com Ancestrais do Continente Asiático , Linfócitos B , Canais de Cálcio Tipo L/genética , Capecitabina/administração & dosagem , Capecitabina/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Complemento C6/genética , Monitoramento de Medicamentos , Tratamento Farmacológico , Estudos de Associação Genética , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico por imagem , Humanos , Hipocalcemia/induzido quimicamente , Imunoglobulinas , Irinotecano/uso terapêutico , Masculino , Mutação , Oxaliplatina/uso terapêutico , Fator de Transcrição PAX3/genética , Sequenciamento Completo do Exoma , Adulto Jovem
9.
Environ Sci Technol ; 53(20): 11988-11998, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31532625

RESUMO

Advanced technologies for toxicity tests are designed to identify biomarkers with superior predictive power or end points of the complex web of biological pathways. However, the data obtained need to be fully characterized for dose-response, physiological systems, and relevance to a system or (sub) population before biological interpretation and decision making. In this study, the toxicity of triclosan (TCS) on zebrafish was selected as a case study to correlate the observed morphological effects with existing data and identify the critical events by receptor activity sensitivity analysis. Triclosan exhibited weak acute toxicity against zebrafish and significantly affected the development of trunk muscles at 0.52, 1.04, and 1.73 µM. Through receptor-mediated screening, we found that the adverse effects of TCS induce Ryanodine receptor 1 (RyR1) activity and distort Ca2+ signaling. The trunk skeletal muscle abnormalities occurred only when the dihydropyridine receptor (DHPR) was blocked, demonstrating that TCS mainly influenced the Ca2+ regulatory module associated with signaling between DHPRs and RyR1; DHPRs mainly regulated the orthograde and retrograde signaling in skeletal muscles. This unexpected result could integrate the mode of action of TCS and provide insight for high-throughput screening and toxicity prediction using zebrafish.


Assuntos
Triclosan , Animais , Canais de Cálcio Tipo L , Fibras Musculares Esqueléticas , Músculo Esquelético , Canal de Liberação de Cálcio do Receptor de Rianodina , Peixe-Zebra
10.
Life Sci ; 235: 116837, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31493481

RESUMO

AIMS: This study aimed to evaluate the effects of the sigma-1 receptor (S1R) on atrial fibrillation (AF) susceptibility in rats. MAIN METHODS: Rats were randomly assigned into three groups for intraperitoneal treatment with saline (CTL group), BD1047 (an antagonist of the S1R, BD group) or BD1047 plus fluvoxamine (an agonist of the S1R, BD + F group) for 4 weeks. The heart rate variability (HRV) and atrial electrophysiological parameters were measured via the PowerLab system and analyzed by LabChart 8.0 software. Atrial histology was determined with Masson staining. The protein levels of connexin (Cx) 40, Cav1.2, S1R, eNOS, p-eNOS, and p-AKT were detected by western blot assays. KEY FINDINGS: Our results showed that BD1047 significantly shortened the atrial effective refractory period (ERP) and action potential duration (APD), increased AF inducibility and duration, augmented sympathetic activity, depressed parasympathetic activity, and reduced heart rate variability (HRV) compared with the CTL group. Masson staining also showed a significant increase in atrial fibrosis in the BD group. Furthermore, the expressions of S1R, Cx40, Cav1.2, p-eNOS, and p-AKT were dramatically reduced in the BD group compared with the CTL group (all P < 0.01). However, fluvoxamine administration mitigated most of the abovementioned alterations. SIGNIFICANCE: Our findings indicated that S1R inhibition contributed to atrial electrical remodeling, cardiac autonomic remodeling and atrial fibrosis, which could be attenuated by fluvoxamine, thus providing new insights into the relationship between the S1R and AF.


Assuntos
Fibrilação Atrial/fisiopatologia , Remodelamento Atrial/fisiologia , Receptores sigma/antagonistas & inibidores , Receptores sigma/fisiologia , Potenciais de Ação , Animais , Fibrilação Atrial/patologia , Canais de Cálcio Tipo L , Conexinas/metabolismo , Etilenodiaminas/farmacologia , Fluvoxamina/farmacologia , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Átrios do Coração/patologia , Frequência Cardíaca/efeitos dos fármacos , Masculino , Óxido Nítrico Sintase Tipo III/metabolismo , Proteína Oncogênica v-akt/metabolismo , Ratos , Receptores sigma/agonistas , Receptores sigma/metabolismo
11.
Adv Exp Med Biol ; 1173: 45-66, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31456205

RESUMO

The key molecular events that provoke Parkinson's disease (PD) are not fully understood. Iron deposit was found in the substantia nigra pars compacta (SNpc) of PD patients and animal models, where dopaminergic neurons degeneration occurred selectively. The mechanisms involved in disturbed iron metabolism remain unknown, however, considerable evidence indicates that iron transporters dysregulation, activation of L-type voltage-gated calcium channel (LTCC) and ATP-sensitive potassium (KATP) channels, as well as N-methyl-D-aspartate (NMDA) receptors (NMDARs) contribute to this process. There is emerging evidence on the structural links and functional modulations between iron and α-synuclein, and the key player in PD which aggregates in Lewy bodies. Iron is believed to modulate α-synuclein synthesis, post-translational modification, and aggregation. Furthermore, glia, especially activated astroglia and microglia, are involved in iron deposit in PD. Glial contributions were largely dependent on the factors they released, e.g., neurotrophic factors, pro-inflammatory factors, lactoferrin, and those undetermined. Therefore, iron chelation using iron chelators, the extracts from many natural foods with iron chelating properties, may be an effective therapy for prevention and treatment of the disease.


Assuntos
Ferro/metabolismo , Doença de Parkinson/fisiopatologia , alfa-Sinucleína/metabolismo , Animais , Canais de Cálcio Tipo L , Neurônios Dopaminérgicos/patologia , Humanos , Canais KATP , Receptores de N-Metil-D-Aspartato , Substância Negra/patologia
12.
Int J Mol Sci ; 20(16)2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31416128

RESUMO

The functional and structural adaptations in cerebral arteries could be one of the fundamental causes in the occurrence of orthostatic intolerance after space flight. In addition, emerging studies have found that many cardiovascular functions exhibit circadian rhythm. Several lines of evidence suggest that space flight might increase an astronaut's cardiovascular risks by disrupting circadian rhythm. However, it remains unknown whether microgravity disrupts the diurnal variation in vascular contractility and whether microgravity impacts on circadian clock system. Sprague-Dawley rats were subjected to 28-day hindlimb-unweighting to simulate the effects of microgravity on vasculature. Cerebrovascular contractility was estimated by investigating vasoconstrictor responsiveness and myogenic tone. The circadian regulation of CaV1.2 channel was determined by recording whole-cell currents, evaluating protein and mRNA expressions. Then the candidate miRNA in relation with Ca2+ signal was screened. Lastly, the underlying pathway involved in circadian regulation of cerebrovascular contractility was determined. The major findings of this study are: (1) The clock gene BMAL1 could induce the expression of miR-103, and in turn modulate the circadian regulation of CaV1.2 channel in rat cerebral arteries at post-transcriptional level; and (2) simulated microgravity disrupted intrinsic diurnal oscillation in rat cerebrovascular contractility by altering circadian regulation of BMAL1/miR-103/CaV1.2 signal pathway.


Assuntos
Fatores de Transcrição ARNTL/genética , Canais de Cálcio Tipo L/metabolismo , Circulação Cerebrovascular/genética , Ritmo Circadiano , MicroRNAs/genética , Vasoconstrição/genética , Ausência de Peso , Fatores de Transcrição ARNTL/metabolismo , Animais , Linhagem Celular , Regulação da Expressão Gênica , Masculino , Modelos Biológicos , Ratos , Transdução de Sinais
13.
Neurosciences (Riyadh) ; 24(3): 225-230, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31380823

RESUMO

Hypokalemic periodic paralysis (HypoPP) is a relatively rare but treatable disorder caused by mutations in the CACNA1S gene. HypoPP patients may experience paralytic episodes associated with hypokalemia and, infrequently, may develop late-onset proximal myopathy. The paralytic attacks are characterized by reversible flaccid paralysis and, in most cases, spare the respiratory muscles and heart. We report a case of CACNA1S periodic paralysis precipitated by vigorous exercise in a 14-year-old boy who presented with sudden-onset paralysis of both his upper and lower extremities. Laboratory evaluation revealed a markedly low serum potassium level. The patients symptoms resolved after correction of the potassium abnormality, and he was discharged with no neurological deficits. Although rare, HypoPP must be differentiated from other causes of weakness and paralysis so that proper treatment can be promptly initiated to ensure good outcomes.


Assuntos
Canais de Cálcio Tipo L/genética , Paralisia Periódica Hipopotassêmica/diagnóstico , Adolescente , Eletrocardiografia , Humanos , Paralisia Periódica Hipopotassêmica/genética , Masculino , Mutação de Sentido Incorreto
15.
Invest Ophthalmol Vis Sci ; 60(8): 3150-3161, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31335952

RESUMO

Purpose: Cav1.4 is a voltage-gated calcium channel clustered at the presynaptic active zones of photoreceptors. Cav1.4 functions in communication by mediating the Ca2+ influx that triggers neurotransmitter release. It also aids in development since rod ribbon synapses do not form in Cav1.4 knock-out mice. Here we used a rescue strategy to investigate the ability of Cav1.4 to trigger synaptogenesis in both immature and mature mouse rods. Methods: In vivo electroporation was used to transiently express Cav α1F or tamoxifen-inducible Cav α1F in a subset of Cav1.4 knock-out mouse rods. Synaptogenesis was assayed using morphologic markers and a vision-guided water maze. Results: We found that introduction of Cav α1F to knock-out terminals rescued synaptic development as indicated by PSD-95 expression and elongated ribbons. When expression of Cav α1F was induced in mature animals, we again found restoration of PSD-95 and elongated ribbons. However, the induced expression of Cav α1F led to diffuse distribution of Cav α1F in the terminal instead of being clustered beneath the ribbon. Approximately a quarter of treated animals passed the water maze test, suggesting the rescue of retinal signaling in these mice. Conclusions: These data confirm that Cav α1F expression is necessary for rod synaptic terminal development and demonstrate that rescue is robust even in adult animals with late stages of synaptic disease. The degree of rod synaptic plasticity seen here should be sufficient to support future vision-restoring treatments such as gene or cell replacement that will require photoreceptor synaptic rewiring.


Assuntos
Canais de Cálcio Tipo L/genética , Células Fotorreceptoras Retinianas Cones/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Transmissão Sináptica/genética , Animais , Animais Recém-Nascidos , Canais de Cálcio Tipo L/metabolismo , Feminino , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Terminações Pré-Sinápticas/metabolismo , Sinapses/metabolismo
16.
BMC Neurol ; 19(1): 157, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291898

RESUMO

BACKGROUND: Hereditary ataxia is a group of neurodegenerative diseases with progressive cerebellar ataxia of the gait and limbs as the main symptoms. The genetic patterns of the disease are diverse but it is mainly divided into autosomal dominant cerebellar ataxia (ADCA) and autosomal recessive cerebellar ataxia (ARCA), and about 45 pathogenic loci have been found in ADCA. The purpose of this study was to explore the genetic defect in a Chinese family with ADCA. METHODS: A three-generation Chinese family with ADCA was enrolled in this study, Exome sequencing was conducted in four family members, including the proband, and verified by Sanger sequencing. RESULTS: The rs779393130 mutation of the CACNA1C gene co-segregated with the ataxia phenotype in this family. The mutation was not detected in 50 unaffected controls. CONCLUSIONS: The rs779393130 mutation of CACNA1C may be associated with the phenotype of the disease. The CACNA1C gene encodes the Cav1.2 (alpha-1) subunit of an L-type calcium channel and this subunit may be related to the ADCA phenotype. These findings may have implications for family clinical monitoring and genetic counseling and may also help in understanding pathogenesis of this disease.


Assuntos
Canais de Cálcio Tipo L/genética , Ataxia Cerebelar/genética , Degenerações Espinocerebelares/genética , Adulto , Grupo com Ancestrais do Continente Asiático , Estudos de Casos e Controles , Feminino , Genes Dominantes , Humanos , Masculino , Mutação , Linhagem , Fenótipo , Adulto Jovem
17.
Life Sci ; 231: 116555, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31194991

RESUMO

AIMS: Caffeine is a methylxanthine with multiple actions in vascular smooth muscle cells (VSMCs), including the increase in the intracellular Ca2+ (iCa2+) concentration by the activation of ryanodine receptors (RyRs). The present study aimed at investigating the participation of Ca2+-influx through different Ca2+-channels on the transient contraction (TC) induced by caffeine in mice mesenteric arteries. MAIN METHODS: Second-order of mesenteric arteries was isolated from male Swiss mice. Vessels without functional endothelium were stimulated with caffeine (10 mM). The caffeine-induced TC was evaluated after the incubation of artery rings for 30 min with the following drugs: nifedipine (10 µM), a Cav1.2 blocker; 2-aminoethoxydiphenyl borate (2-APB; 10 µM) and ruthenium red (RuR; 10 µM), transient receptor potential (TRPs) channels blockers; capsazepine (10 µM) and HC067047 (10 µM), TRPV1 and TRPV4 antagonists, respectively; paxilline (1 µM), a selective BKCa blocker; and SKF-96365 (30 µM), an Orai blocker. Ca2+-fluorescence measurements were also performed on the investigated arteries. KEY FINDINGS: The TC induced by caffeine was partially dependent on Ca2+-influx. However, the blockage of Cav1.2 increased the TC while reduced the iCa2+ signal. Similar results were observed after the blockage of TRPs or BKCa. Therefore, caffeine promoted Ca2+-influx via TRPs and Cav1.2, and hyperpolarization through the activation of BKCa, inducing negative feedback of TC. SIGNIFICANCE: Our results indicate an alternative mechanism for the control of VSMCs contraction in resistance arteries. The evidence of the negative feedback of contraction via TRP-Cav1.2-BKCa provides a new perspective for understanding the mechanism involved in the vascular responses triggered by caffeine.


Assuntos
Cafeína/farmacologia , Canais de Cálcio Tipo L/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Artérias Mesentéricas/efeitos dos fármacos , Animais , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Masculino , Artérias Mesentéricas/metabolismo , Camundongos , Contração Muscular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Canais de Cátion TRPV/metabolismo , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia
18.
Cell Physiol Biochem ; 53(1): 36-48, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31169990

RESUMO

BACKGROUND/AIMS: Ivabradine lowers the heart rate by inhibition of hyperpolarisation-activated cyclic nucleotide-gated (HCN) channels mediating the 'funny' pacemaker current If in the sinoatrial node. It is clinically approved for the treatment of heart failure and angina pectoris. Due to its proposed high selectivity for If administration of ivabradine is not associated with the side effects commonly observed following the application of other heart rate lowering agents. Recent evidence, however, has shown significant affinity of ivabradine towards Kv11.1 (ether-a-go-go related gene, ERG) potassium channels. Despite the inhibition of Kv11.1 channels by ivabradine, cardiac action potential (AP) duration and heart rate corrected QT interval (QTc) of the human electrocardiogram (ECG) were not prolonged. We thus surmised that compensatory mechanisms might counteract the drug's inhibitory action on Kv11.1. METHODS: The effects of ivabradine on human Kv11.1 and Kv7.1 potassium, Cav1.2 calcium, and Nav1.5 sodium channels, heterologously expressed in tsA-201 cells, were studied in the voltage-clamp mode of the whole cell patch clamp technique. In addition, changes in action potential parameters of human induced pluripotent stem cell (iPSC) derived cardiomyocytes upon application of ivabradine were studied with current-clamp experiments. RESULTS: Here we show that ivabradine exhibits significant affinity towards cardiac ion channels other than HCN. We demonstrate for the first time inhibition of human voltage-gated Nav1.5 sodium channels at therapeutically relevant concentrations. Within this study we also confirm recent findings of human Kv11.1 inhibition by low µM concentrations of ivabradine and observed no prolongation of ventricular-like APs in cardiomyocytes derived from iPSCs. CONCLUSION: Our results provide an explanation why ivabradine, despite its affinity for Kv11.1 channels, does not prolong the cardiac AP and QTc interval. Furthermore, our results suggest the inhibition of voltage-gated Nav1.5 sodium channels to underlie the recent observations of slowed atrioventricular conduction by increased atrial-His bundle intervals upon administration of ivabradine.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Fármacos Cardiovasculares/farmacologia , Canais Iônicos/metabolismo , Ivabradina/farmacologia , Canais de Cálcio Tipo L/química , Canais de Cálcio Tipo L/metabolismo , Linhagem Celular , Canal de Potássio ERG1/antagonistas & inibidores , Canal de Potássio ERG1/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Canais Iônicos/antagonistas & inibidores , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Canal de Sódio Disparado por Voltagem NAV1.5/química , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Técnicas de Patch-Clamp
19.
Cells ; 8(6)2019 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-31185584

RESUMO

Safety is one of the most important and critical issues in drug development. Many drugs were abandoned in clinical trials and retracted from the market because of unknown side effects. Cardiotoxicity is one of the most common reasons for drug retraction due to its potential side effects, i.e., inducing either tachycardia, bradycardia or arrhythmia. The zebrafish model could be used to screen drug libraries with potential cardiotoxicity in a high-throughput manner. In addition, the fundamental principles of replacement, reduction, and refinement of laboratory animal usage, 3R, could be achieved by using zebrafish as an alternative to animal models. In this study, we used a simple ImageJ-based method to evaluate and screen 70 ion channel ligands and successfully identify six compounds with strong cardiotoxicity in vivo. Next, we conducted an in silico-based molecular docking simulation to elucidate five identified compounds that might interact with domain III or domain IV of the Danio rerio L-type calcium channel (LTCC), a known pharmaceutically important target for arrhythmia. In conclusion, in this study, we provide a web lab and dry lab combinatorial approach to perform in vivo cardiotoxicity drug screening and in silico mechanistic studies.


Assuntos
Frequência Cardíaca , Canais Iônicos/metabolismo , Ligantes , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Animais , Sítios de Ligação , Canais de Cálcio Tipo L/química , Canais de Cálcio Tipo L/metabolismo , Embrião não Mamífero/metabolismo , Frequência Cardíaca/efeitos dos fármacos , Ligações de Hidrogênio , Canais Iônicos/química , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologia , Peixe-Zebra/crescimento & desenvolvimento , Proteínas de Peixe-Zebra/química
20.
Eur J Pharmacol ; 858: 172455, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31202801

RESUMO

Hydrogen sulfide (H2S) exerts different effects on the cardiovascular system by modulating ion channels. The present study was to ascertain whether H2S affects L-type calcium (Ca2+) channels in vascular smooth muscle cells (VSMCs) and the subsequent signaling pathways. Here, CaV1.2 L-type Ca2+ currents (ICa, L) were inhibited by sodium hydrosulfide (NaHS, an H2S donor) in A7r5 cell lines using the whole-cell patch-clamp technique. Then NaHS significantly reduced intracellular Ca2+ concentration ([Ca2+]i) in Bayk8644-stimulated CaV1.2-HEK293 cells by using flow cytometry. However, NaHS did not affect the ryanodine-induced elevation of [Ca2+]i by means of confocal microscopy, ruling out its influence on the intracellular Ca2+ release. In the following, the sulfhydration of L-type Ca2+ channels was determined by Ellman's Test. The results showed that NaHS decreased the number of free sulfhydryls, which was further strengthened by the oxidant sulfhydryl modifier diamide (DM) and significantly counteracted by the reductant sulfhydryl modifier dithiothreitol (DTT). DTT also partly reversed the NaHS-reduced [Ca2+]i in CaV1.2-HEK293 cells. Additionally, NaHS did not change CaV1.2 expression. Furthermore, NaHS increased phosphorylation of PKC and ERK in both a concentration- and a time-dependent manner in VSMCs. Isradipine, L-type Ca2+ channel specific blocker, further increased H2S-induced phosphorylation of PKC and ERK, showing an additive effect with H2S. Therefore, our results suggest that H2S reduced ICa, L & [Ca2+]i and hence influenced the downstream PKC/ERK pathway, which was likely through regulating the sulfhydration of L-type Ca2+ channels in VSMCs.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/metabolismo , Sulfeto de Hidrogênio/farmacologia , Músculo Liso Vascular/citologia , Animais , Relação Dose-Resposta a Droga , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células HEK293 , Humanos , Músculo Liso Vascular/metabolismo , Proteína Quinase C/metabolismo , Ratos , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo
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