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1.
Chemosphere ; 261: 128051, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113650

RESUMO

The potential toxicity of copper nanoparticles (CuNPs) to early stages of fishes is not fully understood, and little is known about their effects on ionocytes and associated functions. This study used zebrafish embryos as a model to investigate the toxic effects of CuNPs on two subtypes of ionocytes. Zebrafish embryos were exposed to 0.1, 1, and 3 mg L-1 CuNPs for 96 h. After exposure, whole-body Na+ and Ca2+ contents were significantly reduced at ≥0.1 mg L-1, while the K+ content had decreased at ≥1 mg L-1. H+ and NH4+ excretion by the skin significantly decreased at ≥1 mg L-1. The number of living ionocytes labeled with rhodamine-123 had significantly decreased with ≥0.1 mg L-1 CuNPs. The ionocyte subtypes of H+-ATPase-rich (HR) and Na+/K+-ATPase-rich (NaR) cells were labeled by immunostaining and had decreased with ≥1 mg L-1. Shrinkage of the apical opening of ionocytes was revealed by scanning electronic microscopy. Functional impairment was also reflected by changes in gene expressions, including ion transporters/channels and Ca2+-regulatory hormones. This study shows that CuNP exposure can impair two subtypes of ionocytes and their associated functions, including Na+/Ca2+ uptake and H+/NH4+ excretion in zebrafish embryos.


Assuntos
Amônia/metabolismo , Cobre/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Nanopartículas/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Ácidos/metabolismo , Animais , Transporte Biológico , Cálcio/metabolismo , Cobre/metabolismo , Embrião não Mamífero/metabolismo , Canais Iônicos/metabolismo , Íons/metabolismo , Nanopartículas/metabolismo , Pele/metabolismo , Sódio/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Poluentes Químicos da Água/metabolismo , Proteínas de Peixe-Zebra/metabolismo
2.
Neuron ; 108(1): 5-7, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-33058766

RESUMO

Like axon guidance, the tuning of vascular tip cells during angiogenesis is an intriguing but puzzling developmental process. A new study in zebrafish (Liu et al., 2020) now demonstrates a critical role of the Piezo1 mechanosensitive ion channel in guiding vascular tip cells in pathfinding.


Assuntos
Cálcio , Mecanotransdução Celular , Animais , Encéfalo/metabolismo , Células Endoteliais/metabolismo , Canais Iônicos/genética , Canais Iônicos/metabolismo
3.
Channels (Austin) ; 14(1): 403-412, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33092458

RESUMO

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has prompted an urgent need to identify effective medicines for the prevention and treatment of the disease. A comparative analysis between SARS-CoV-2 and Hepatitis C Virus (HCV) can expand the available knowledge regarding the virology and potential drug targets against these viruses. Interestingly, comparing HCV with SARS-CoV-2 reveals major similarities between them, ranging from the ion channels that are utilized, to the symptoms that are exhibited by patients. Via this comparative analysis, and from what is known about HCV, the most promising treatments for COVID-19 can focus on the reduction of viral load, treatment of pulmonary system damages, and reduction of inflammation. In particular, the drugs that show most potential in this regard include ritonavir, a combination of peg-IFN, and lumacaftor-ivacaftor. This review anaylses SARS-CoV-2 from the perspective of the role of ion homeostasis and channels in viral pathomechanism. We also highlight other novel treatment approaches that can be used for both treatment and prevention of COVID-19. The relevance of this review is to offer high-quality evidence that can be used as the basis for the identification of potential solutions to the COVID-19 pandemic.


Assuntos
Betacoronavirus/metabolismo , Infecções por Coronavirus/metabolismo , Hepacivirus/metabolismo , Canais Iônicos/metabolismo , Pneumonia Viral/metabolismo , Animais , Betacoronavirus/patogenicidade , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Hepacivirus/patogenicidade , Hepatite C/metabolismo , Hepatite C/virologia , Humanos , Pandemias , Pneumonia Viral/patologia , Pneumonia Viral/virologia
4.
J Vis Exp ; (162)2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32865526

RESUMO

Battling human neurodegenerative pathologies and managing their pervasive socioeconomic impact is becoming a global priority. Notwithstanding their detrimental effects on the human life quality and the healthcare system, the majority of human neurodegenerative disorders still remain incurable and non-preventable. Therefore, the development of novel therapeutic interventions against such maladies is becoming a pressing urgency. Age-associated deterioration of neuronal circuits and function is evolutionarily conserved in organisms as diverse as the lowly worm Caenorhabditis elegans and humans, signifying similarities in the underlying cellular and molecular mechanisms. C. elegans is a highly malleable genetic model, which offers a well-characterized nervous system, body transparency and a diverse repertoire of genetic and imaging techniques to assess neuronal activity and quality control during ageing. Here, we introduce and describe methodologies utilizing some versatile nematode models, including hyperactivated ion channel-induced necrosis (e.g., deg-3(d) and mec-4(d)) and protein aggregate (e.g., α-syunclein and poly-glutamate)-induced neurotoxicity, to monitor and dissect the cellular and molecular underpinnings of age-related neuronal breakdown. A combination of these animal neurodegeneration models, together with genetic and pharmacological screens for cell death modulators will lead to an unprecedented understanding of age-related breakdown of neuronal function and will provide critical insights with broad relevance to human health and quality of life.


Assuntos
Envelhecimento/metabolismo , Envelhecimento/patologia , Caenorhabditis elegans , Modelos Animais de Doenças , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Animais , Morte Celular , Humanos , Canais Iônicos/metabolismo , Necrose , Doenças Neurodegenerativas/fisiopatologia , Neurônios/metabolismo , Neurônios/patologia , Qualidade de Vida
5.
Proc Natl Acad Sci U S A ; 117(37): 22833-22840, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32873643

RESUMO

Channelrhodopsins are light-gated ion channels widely used to control neuronal firing with light (optogenetics). We report two previously unknown families of anion channelrhodopsins (ACRs), one from the heterotrophic protists labyrinthulea and the other from haptophyte algae. Four closely related labyrinthulea ACRs, named RubyACRs here, exhibit a unique retinal-binding pocket that creates spectral sensitivities with maxima at 590 to 610 nm, the most red-shifted channelrhodopsins known, long-sought for optogenetics, and more broadly the most red-shifted microbial rhodopsins thus far reported. We identified three spectral tuning residues critical for the red-shifted absorption. Photocurrents recorded from the RubyACR from Aurantiochytrium limacinum (designated AlACR1) under single-turnover excitation exhibited biphasic decay, the rate of which was only weakly voltage dependent, in contrast to that in previously characterized cryptophyte ACRs, indicating differences in channel gating mechanisms between the two ACR families. Moreover, in A. limacinum we identified three ACRs with absorption maxima at 485, 545, and 590 nm, indicating color-sensitive photosensing with blue, green, and red spectral variation of ACRs within individual species of the labyrinthulea family. We also report functional energy transfer from a cytoplasmic fluorescent protein domain to the retinal chromophore bound within RubyACRs.


Assuntos
Channelrhodopsins/química , Ativação do Canal Iônico/fisiologia , Ânions/metabolismo , Criptófitas/genética , Células HEK293 , Humanos , Canais Iônicos/química , Canais Iônicos/metabolismo , Luz , Potenciais da Membrana/fisiologia , Neurônios/metabolismo , Optogenética/métodos , Rodopsina/metabolismo
6.
Life Sci ; 259: 118276, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32798560

RESUMO

AIMS: The mechanisms underlying the fetal origin of renal disease remains unknown. This study aimed to investigate the profiles of ion channel and transporter proteins in the fetal kidney in fetal growth restriction (FGR)rats, and to explore their association with the fetal origin of renal disease. MAIN METHODS: An FGR rat model was developed by administration of a low-protein diet. Then 367 differentially expressed proteins (DEPs) from quantitative proteome analysis were subjected to Ingenuity Pathway Analysis. 22 DEPs associated with ion channels/transporters were evaluated in the fetal kidney. Na+/H+ exchanger1(NHE1) and its downstream unfolded protein response (UPR) pathway were investigated. Furthermore, overexpression of NHE1 were achieved via plasmid transfection to evaluate the potential influence on the UPR pathway and cell apoptosis in human proximal tubular epithelial cell line HK2 cells. KEY FINDINGS: Findings were as follows: 1) In the FGR fetal kidney, aquaporin 2/4, solute carrier (SLC) 8a1, 33a1, etc. were downregulated, whereas other transporters including SLC 2a1, 4a1, 9a1, 29a3, etc. were upregulated. 2) NHE1 mRNA levels were markedly elevated in the FGR fetus. Further investigation revealed an increase in the UPR pathway regulators. 3) In vitro study showed that NHE1 overexpression in HK2 cells significantly induced expression of the endoplasmic reticulum stress (ERS) regulators and led to a decrease in the anti-apoptotic potential. SIGNIFICANCE: We speculate that maternal protein malnutrition causes dysregulation of ion channels/transporters in the fetal kidney. Upregulated NHE1 may activate the UPR pathway and induce cell apoptosis thus leading to impairment of kidney function.


Assuntos
Estresse do Retículo Endoplasmático/fisiologia , Retardo do Crescimento Fetal/metabolismo , Canais Iônicos/metabolismo , Nefropatias/metabolismo , Rim/embriologia , Proteínas de Membrana Transportadoras/metabolismo , Animais , Apoptose/fisiologia , Linhagem Celular , Humanos , Rim/metabolismo , Masculino , Ratos , Trocador 1 de Sódio-Hidrogênio/metabolismo , Resposta a Proteínas não Dobradas
7.
Nat Commun ; 11(1): 4070, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32792502

RESUMO

Human astroviruses are small non-enveloped viruses with positive-sense single-stranded RNA genomes. Astroviruses cause acute gastroenteritis in children worldwide and have been associated with encephalitis and meningitis in immunocompromised individuals. It is still unknown how astrovirus particles exit infected cells following replication. Through comparative genomic analysis and ribosome profiling we here identify and confirm the expression of a conserved alternative-frame ORF, encoding the protein XP. XP-knockout astroviruses are attenuated and pseudo-revert on passaging. Further investigation into the function of XP revealed plasma and trans Golgi network membrane-associated roles in virus assembly and/or release through a viroporin-like activity. XP-knockout replicons have only a minor replication defect, demonstrating the role of XP at late stages of infection. The discovery of XP advances our knowledge of these important human viruses and opens an additional direction of research into their life cycle and pathogenesis.


Assuntos
Canais Iônicos/metabolismo , Mamastrovirus/metabolismo , Proteínas não Estruturais Virais/metabolismo , Animais , Linhagem Celular , Cricetinae , Eletroforese em Gel de Poliacrilamida , Genômica/métodos , Células HeLa , Humanos , Immunoblotting , Imunoprecipitação , Canais Iônicos/genética , Mamastrovirus/genética , Microscopia de Fluorescência , Plasmídeos/genética , Ribossomos , Proteínas não Estruturais Virais/genética , Replicação Viral/genética , Replicação Viral/fisiologia
8.
Nature ; 585(7823): 129-134, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32848250

RESUMO

Transmembrane channels and pores have key roles in fundamental biological processes1 and in biotechnological applications such as DNA nanopore sequencing2-4, resulting in considerable interest in the design of pore-containing proteins. Synthetic amphiphilic peptides have been found to form ion channels5,6, and there have been recent advances in de novo membrane protein design7,8 and in redesigning naturally occurring channel-containing proteins9,10. However, the de novo design of stable, well-defined transmembrane protein pores that are capable of conducting ions selectively or are large enough to enable the passage of small-molecule fluorophores remains an outstanding challenge11,12. Here we report the computational design of protein pores formed by two concentric rings of α-helices that are stable and monodisperse in both their water-soluble and their transmembrane forms. Crystal structures of the water-soluble forms of a 12-helical pore and a 16-helical pore closely match the computational design models. Patch-clamp electrophysiology experiments show that, when expressed in insect cells, the transmembrane form of the 12-helix pore enables the passage of ions across the membrane with high selectivity for potassium over sodium; ion passage is blocked by specific chemical modification at the pore entrance. When incorporated into liposomes using in vitro protein synthesis, the transmembrane form of the 16-helix pore-but not the 12-helix pore-enables the passage of biotinylated Alexa Fluor 488. A cryo-electron microscopy structure of the 16-helix transmembrane pore closely matches the design model. The ability to produce structurally and functionally well-defined transmembrane pores opens the door to the creation of designer channels and pores for a wide variety of applications.


Assuntos
Simulação por Computador , Genes Sintéticos/genética , Canais Iônicos/química , Canais Iônicos/genética , Modelos Moleculares , Biologia Sintética , Linhagem Celular , Microscopia Crioeletrônica , Cristalografia por Raios X , Condutividade Elétrica , Escherichia coli/genética , Escherichia coli/metabolismo , Hidrazinas , Canais Iônicos/metabolismo , Transporte de Íons , Lipossomos/metabolismo , Técnicas de Patch-Clamp , Porinas/química , Porinas/genética , Porinas/metabolismo , Engenharia de Proteínas , Estrutura Secundária de Proteína , Solubilidade , Água/química
9.
Proc Natl Acad Sci U S A ; 117(34): 20378-20389, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32764146

RESUMO

The phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP2), has long been established as a major contributor to intracellular signaling, primarily by virtue of its role as a substrate for phospholipase C (PLC). Signaling by Gq-protein-coupled receptors triggers PLC-mediated hydrolysis of PIP2 into inositol 1,4,5-trisphosphate and diacylglycerol, which are well known to modulate vascular ion channel activity. Often overlooked, however, is the role PIP2 itself plays in this regulation. Although numerous reports have demonstrated that PIP2 is critical for ion channel regulation, how it impacts vascular function has received scant attention. In this review, we focus on PIP2 as a regulator of ion channels in smooth muscle cells and endothelial cells-the two major classes of vascular cells. We further address the concerted effects of such regulation on vascular function and blood flow control. We close with a consideration of current knowledge regarding disruption of PIP2 regulation of vascular ion channels in disease.


Assuntos
Células Endoteliais/metabolismo , Canais Iônicos/metabolismo , Miócitos de Músculo Liso/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Animais , Endotélio Vascular/metabolismo , Humanos , Músculo Liso Vascular/metabolismo , Doenças Vasculares/metabolismo
10.
Proc Natl Acad Sci U S A ; 117(34): 20898-20907, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32788354

RESUMO

The voltage-gated proton channel Hv1 is a member of the voltage-gated ion channel superfamily, which stands out in design: It is a dimer of two voltage-sensing domains (VSDs), each containing a pore pathway, a voltage sensor (S4), and a gate (S1) and forming its own ion channel. Opening of the two channels in the dimer is cooperative. Part of the cooperativity is due to association between coiled-coil domains that extend intracellularly from the S4s. Interactions between the transmembrane portions of the subunits may also contribute, but the nature of transmembrane packing is unclear. Using functional analysis of a mutagenesis scan, biochemistry, and modeling, we find that the subunits form a dimer interface along the entire length of S1, and also have intersubunit contacts between S1 and S4. These interactions exert a strong effect on gating, in particular on the stability of the open state. Our results suggest that gating in Hv1 is tuned by extensive VSD-VSD interactions between the gates and voltage sensors of the dimeric channel.


Assuntos
Canais Iônicos/metabolismo , Sequência de Aminoácidos , Humanos , Ativação do Canal Iônico , Canais Iônicos/química , Modelos Moleculares , Conformação Proteica , Multimerização Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Prótons
11.
Neuron ; 108(1): 180-192.e5, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-32827455

RESUMO

During development, endothelial tip cells (ETCs) located at the leading edge of growing vascular plexus guide angiogenic sprouts to target vessels, and thus, ETC pathfinding is fundamental for vascular pattern formation in organs, including the brain. However, mechanisms of ETC pathfinding remain largely unknown. Here, we report that Piezo1-mediated Ca2+ activities at primary branches of ETCs regulate branch dynamics to accomplish ETC pathfinding during zebrafish brain vascular development. ETC branches display spontaneous local Ca2+ transients, and high- and low-frequency Ca2+ transients cause branch retraction through calpain and branch extension through nitric oxide synthase, respectively. These Ca2+ transients are mainly mediated by Ca2+-permeable Piezo1 channels, which can be activated by mechanical force, and mutating piezo1 largely impairs ETC pathfinding and brain vascular patterning. These findings reveal that Piezo1 and downstream Ca2+ signaling act as molecular bases for ETC pathfinding and highlight a novel function of Piezo1 and Ca2+ in vascular development.


Assuntos
Vasos Sanguíneos/crescimento & desenvolvimento , Encéfalo/irrigação sanguínea , Cálcio/metabolismo , Células Endoteliais/metabolismo , Canais Iônicos/genética , Neovascularização Fisiológica/genética , Proteínas de Peixe-Zebra/genética , Animais , Encéfalo/crescimento & desenvolvimento , Sinalização do Cálcio , Calpaína/metabolismo , Canais Iônicos/metabolismo , Mecanotransdução Celular , Mutação , Óxido Nítrico Sintase/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra/metabolismo
12.
Nat Commun ; 11(1): 4331, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859914

RESUMO

Gap junctions establish direct pathways for cells to transfer metabolic and electrical messages. The local lipid environment is known to affect the structure, stability and intercellular channel activity of gap junctions; however, the molecular basis for these effects remains unknown. Here, we incorporate native connexin-46/50 (Cx46/50) intercellular channels into a dual lipid nanodisc system, mimicking a native cell-to-cell junction. Structural characterization by CryoEM reveals a lipid-induced stabilization to the channel, resulting in a 3D reconstruction at 1.9 Å resolution. Together with all-atom molecular dynamics simulations, it is shown that Cx46/50 in turn imparts long-range stabilization to the dynamic local lipid environment that is specific to the extracellular lipid leaflet. In addition, ~400 water molecules are resolved in the CryoEM map, localized throughout the intercellular permeation pathway and contributing to the channel architecture. These results illustrate how the aqueous-lipid environment is integrated with the architectural stability, structure and function of gap junction communication channels.


Assuntos
Conexinas/química , Conexinas/metabolismo , Microscopia Crioeletrônica/métodos , Transporte Biológico , Junções Comunicantes/metabolismo , Canais Iônicos/metabolismo , Simulação de Dinâmica Molecular , Conformação Proteica
13.
Biochem Biophys Res Commun ; 530(1): 10-14, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32828269

RESUMO

COVID-19 is one of the most impactful pandemics in recorded history. As such, the identification of inhibitory drugs against its etiological agent, SARS-CoV-2, is of utmost importance, and in particular, repurposing may provide the fastest route to curb the disease. As the first step in this route, we sought to identify an attractive and viable target in the virus for pharmaceutical inhibition. Using three bacteria-based assays that were tested on known viroporins, we demonstrate that one of its essential components, the E protein, is a potential ion channel and, therefore, is an excellent drug target. Channel activity was demonstrated for E proteins in other coronaviruses, providing further emphasis on the importance of this functionally to the virus' pathogenicity. The results of a screening effort involving a repurposing drug library of ion channel blockers yielded two compounds that inhibit the E protein: Gliclazide and Memantine. In conclusion, as a route to curb viral virulence and abate COVID-19, we point to the E protein of SARS-CoV-2 as an attractive drug target and identify off-label compounds that inhibit it.


Assuntos
Antivirais/farmacologia , Betacoronavirus/efeitos dos fármacos , Gliclazida/farmacologia , Canais Iônicos/antagonistas & inibidores , Memantina/farmacologia , Proteínas do Envelope Viral/antagonistas & inibidores , Betacoronavirus/metabolismo , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/virologia , Descoberta de Drogas , Reposicionamento de Medicamentos , Humanos , Canais Iônicos/metabolismo , Pandemias , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/virologia , Proteínas do Envelope Viral/metabolismo
14.
Nat Commun ; 11(1): 3568, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32678085

RESUMO

Dissemination of transformed cells is a key process in metastasis. Despite its importance, how transformed cells disseminate from an intact tissue and enter the circulation is poorly understood. Here, we use a fully developed tissue, Drosophila midgut, and describe the morphologically distinct steps and the cellular events occurring over the course of RasV12-transformed cell dissemination. Notably, RasV12-transformed cells formed the Actin- and Cortactin-rich invasive protrusions that were important for breaching the extracellular matrix (ECM) and visceral muscle. Furthermore, we uncovered the essential roles of the mechanosensory channel Piezo in orchestrating dissemination of RasV12-transformed cells. Collectively, our study establishes an in vivo model for studying how transformed cells migrate out from a complex tissue and provides unique insights into the roles of Piezo in invasive cell behavior.


Assuntos
Proteínas de Drosophila/metabolismo , Canais Iônicos/metabolismo , Mecanotransdução Celular , Invasividade Neoplásica/patologia , Proteínas ras/metabolismo , Animais , Membrana Basal/metabolismo , Membrana Basal/patologia , Transformação Celular Neoplásica , Modelos Animais de Doenças , Drosophila , Proteínas de Drosophila/genética , Vesículas Extracelulares/metabolismo , Trato Gastrointestinal/patologia , Genes ras , Canais Iônicos/genética , Metástase Neoplásica/patologia , Podossomos/metabolismo , Proteínas ras/genética
15.
Nat Commun ; 11(1): 3690, 2020 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-32704140

RESUMO

Mechanosensitive ion channels transduce physical force into electrochemical signaling that underlies an array of fundamental physiological processes, including hearing, touch, proprioception, osmoregulation, and morphogenesis. The mechanosensitive channels of small conductance (MscS) constitute a remarkably diverse superfamily of channels critical for management of osmotic pressure. Here, we present cryo-electron microscopy structures of a MscS homolog from Arabidopsis thaliana, MSL1, presumably in both the closed and open states. The heptameric MSL1 channel contains an unusual bowl-shaped transmembrane region, which is reminiscent of the evolutionarily and architecturally unrelated mechanosensitive Piezo channels. Upon channel opening, the curved transmembrane domain of MSL1 flattens and expands. Our structures, in combination with functional analyses, delineate a structural mechanism by which mechanosensitive channels open under increased membrane tension. Further, the shared structural feature between unrelated channels suggests the possibility of a unified mechanical gating mechanism stemming from membrane deformation induced by a non-planar transmembrane domain.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Eucariotos/metabolismo , Ativação do Canal Iônico , Canais Iônicos/química , Canais Iônicos/metabolismo , Mecanotransdução Celular , Proteínas de Arabidopsis/ultraestrutura , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Canais Iônicos/ultraestrutura , Modelos Moleculares , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Domínios Proteicos , Estrutura Secundária de Proteína
16.
PLoS One ; 15(7): e0235922, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32673370

RESUMO

We have previously established that epigenetic regulator RING1 and YY1 binding protein (RYBP) is required for the contractility of embryonic stem (ES) cell derived cardiomyocytes (CMCs), suggesting its essential role in contractility. In order to investigate the underlying molecular events of this phenotype, we compared the transcriptomic profile of the wild type and Rybp null mutant ES cells and CMCs differentiated from these cell lines. We identified genes related to ion homeostasis, cell adhesion and sarcomeric organization affected in the Rybp null mutant CMCs, by using hierarchical gene clustering and Gene Ontology analysis. We have also demonstrated that the amount of RYBP is drastically reduced in the terminally differentiated wild type CMCs whilst it is broadly expressed in the early phase of differentiation when progenitors form. We also describe that RYBP is important for the proper expression of key cardiac transcription factors including Mesp1, Shh and Mef2c. These findings identify Rybp as a gene important for both early cardiac gene transcription and consequent sarcomere formation necessary for contractility. Since impairment of sarcomeric function and contractility plays a central role in reduced cardiac pump function leading to heart failures in human, current results might be relevant to the pathophysiology of cardiomyopathies.


Assuntos
Proteínas Repressoras/genética , Sarcômeros/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Diferenciação Celular , Linhagem Celular , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Canais Iônicos/genética , Canais Iônicos/metabolismo , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , RNA Mensageiro/metabolismo , Proteínas Repressoras/deficiência
17.
Am J Physiol Renal Physiol ; 319(2): F257-F283, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32628539

RESUMO

Urinary bladder smooth muscle (UBSM), also known as detrusor smooth muscle, forms the bladder wall and ultimately determines the two main attributes of the organ: urine storage and voiding. The two functions are facilitated by UBSM relaxation and contraction, respectively, which depend on UBSM excitability shaped by multiple ion channels. In this review, we summarize the current understanding of key ion channels establishing and regulating UBSM excitability and contractility. They include excitation-enhancing voltage-gated Ca2+ (Cav) and transient receptor potential channels, excitation-reducing K+ channels, and still poorly understood Cl- channels. Dynamic interplay among UBSM ion channels determines the overall level of Cav channel activity. The net Ca2+ influx via Cav channels increases global intracellular Ca2+ concentration, which subsequently triggers UBSM contractility. Here, for each ion channel type, we describe UBSM tissue/cell expression (mRNA and protein) profiles and their role in regulating excitability and contractility of UBSM in various animal species, including the mouse, rat, and guinea pig, and, most importantly, humans. The currently available data reveal certain interspecies differences, which complicate the translational value of published animal research results to humans. This review highlights recent developments, findings on genetic knockout models, pharmacological data, reports on UBSM ion channel dysfunction in animal bladder disease models, and the very limited human studies currently available. Among all gaps in present-day knowledge, the unknowns on expression and functional roles for ion channels determined directly in human UBSM tissues and cells under both normal and disease conditions remain key hurdles in the field.


Assuntos
Canais Iônicos/metabolismo , Músculo Liso/metabolismo , Miócitos de Músculo Liso/metabolismo , Bexiga Urinária/metabolismo , Animais , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Contração Muscular/fisiologia
18.
Nat Commun ; 11(1): 3351, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620897

RESUMO

The sodium-leak channel NALCN forms a subthreshold sodium conductance that controls the resting membrane potentials of neurons. The auxiliary subunits of the channel and their functions in mammals are largely unknown. In this study, we demonstrate that two large proteins UNC80 and UNC79 are subunits of the NALCN complex. UNC80 knockout mice are neonatal lethal. The C-terminus of UNC80 contains a domain that interacts with UNC79 and overcomes a soma-retention signal to achieve dendritic localization. UNC80 lacking this domain, as found in human patients, still supports whole-cell NALCN currents but lacks dendritic localization. Our results establish the subunit composition of the NALCN complex, uncover the inter-subunit interaction domains, reveal the functional significance of regulation of dendritic membrane potential by the sodium-leak channel complex, and provide evidence supporting that genetic variations found in individuals with intellectual disability are the causes for the phenotype observed in patients.


Assuntos
Proteínas de Transporte/genética , Deficiência Intelectual/genética , Canais Iônicos/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/genética , Animais , Proteínas de Transporte/metabolismo , Criança , Análise Mutacional de DNA , Conjuntos de Dados como Assunto , Dendritos/patologia , Modelos Animais de Doenças , Técnicas de Introdução de Genes , Células HEK293 , Hipocampo/citologia , Hipocampo/patologia , Humanos , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/patologia , Canais Iônicos/genética , Masculino , Camundongos , Camundongos Knockout , Mutação , Proteínas do Tecido Nervoso/metabolismo , Cultura Primária de Células , Domínios Proteicos/genética , Índice de Gravidade de Doença , Sequenciamento Completo do Exoma
19.
Life Sci ; 257: 118047, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32629001

RESUMO

AIM: The purpose of the study was to investigate what effects the sigma-1 receptor (S1R) could exert on the cardiac myocyte ion channels in a rodent model of depression and to explore the underlying mechanisms since depression is an independent risk factor for cardiovascular diseases including ventricular arrhythmias (VAs). MATERIALS AND METHODS: To establish the depression model in rats, chronic mild unpredictable stress (CMUS) for 28 days was used. The S1R agonist fluvoxamine was injected intraperitoneally from the second week to the last week for 21 days in total, and the effects were evaluated by patch clamp, western blot analysis, and Masson staining. KEY FINDINGS: We demonstrated that depression was improved after treatment with fluvoxamine. In addition, the prolongation of the corrected QT (QTc) interval under CMUS that increased vulnerability to VAs was significantly attenuated by stimulation of S1R due to the decreased amplitude of L-type calcium current (ICa-L) and the restoration of reduced transient outward potassium current (Ito) resulting from CMUS induction. The S1R also decelerated Ito inactivation and accelerated Ito recovery by activating Ca2+/calmodulin-dependent kinase II. Moreover, the stimulation of S1R ameliorated the structural remodeling as the substrate for maintenance of VAs. All these effects were abolished by the administration of S1R antagonist BD1047, which verified the roles for S1R. SIGNIFICANCE: Activation of S1R could decrease the vulnerability to VAs by inhibiting ICa-L and restoring Ito, in addition to ameliorating the CMUS-induced depressive symptoms and structural remodeling.


Assuntos
Depressão/metabolismo , Miócitos Cardíacos/metabolismo , Receptores sigma/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Arritmias Cardíacas/metabolismo , Depressão/fisiopatologia , Transtorno Depressivo/metabolismo , Transtorno Depressivo/fisiopatologia , Modelos Animais de Doenças , Fluvoxamina/metabolismo , Fluvoxamina/farmacologia , Ventrículos do Coração/efeitos dos fármacos , Canais Iônicos/efeitos dos fármacos , Canais Iônicos/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Receptores sigma/metabolismo , Remodelação Ventricular/efeitos dos fármacos , Remodelação Ventricular/fisiologia
20.
PLoS One ; 15(7): e0236361, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32706793

RESUMO

MEdiator of cell MOtility1 (MEMO1) is a ubiquitously expressed redox protein involved in extracellular ligand-induced cell signaling. We previously reported that inducible whole-body Memo1 KO (cKO) mice displayed a syndrome of premature aging and disturbed mineral metabolism partially recapitulating the phenotype observed in Klotho or Fgf23-deficient mouse models. Here, we aimed at delineating the contribution of systemic mineral load on the Memo1 cKO mouse phenotype. We attempted to rescue the Memo1 cKO phenotype by depleting phosphate or vitamin D from the diet, but did not observe any effect on survival. However, we noticed that, by contrast to Klotho or Fgf23-deficient mouse models, Memo1 cKO mice did not present any soft-tissue calcifications and displayed even a decreased serum calcification propensity. We identified higher serum magnesium levels as the main cause of protection against calcifications. Expression of genes encoding intestinal and renal magnesium channels and the regulator epidermal growth factor were increased in Memo1 cKO. In order to check whether magnesium reabsorption in the kidney alone was driving the higher magnesemia, we generated a kidney-specific Memo1 KO (kKO) mouse model. Memo1 kKO mice also displayed higher magnesemia and increased renal magnesium channel gene expression. Collectively, these data identify MEMO1 as a novel regulator of magnesium homeostasis and systemic calcification propensity, by regulating expression of the main magnesium channels.


Assuntos
Calcinose/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Rim/metabolismo , Magnésio/sangue , Animais , Calcinose/genética , Feminino , Homeostase , Peptídeos e Proteínas de Sinalização Intracelular/genética , Canais Iônicos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfatos/metabolismo , Vitamina D/metabolismo
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