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1.
Proc Natl Acad Sci U S A ; 117(33): 20159-20170, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32747553

RESUMO

Although immune checkpoint blockade (ICB) therapy has revolutionized cancer treatment, many patients do not respond or develop resistance to ICB. N6 -methylation of adenosine (m6A) in RNA regulates many pathophysiological processes. Here, we show that deletion of the m6A demethylase Alkbh5 sensitized tumors to cancer immunotherapy. Alkbh5 has effects on m6A density and splicing events in tumors during ICB. Alkbh5 modulates Mct4/Slc16a3 expression and lactate content of the tumor microenvironment and the composition of tumor-infiltrating Treg and myeloid-derived suppressor cells. Importantly, a small-molecule Alkbh5 inhibitor enhanced the efficacy of cancer immunotherapy. Notably, the ALKBH5 gene mutation and expression status of melanoma patients correlate with their response to immunotherapy. Our results suggest that m6A demethylases in tumor cells contribute to the efficacy of immunotherapy and identify ALKBH5 as a potential therapeutic target to enhance immunotherapy outcome in melanoma, colorectal, and potentially other cancers.


Assuntos
Homólogo AlkB 5 da RNA Desmetilase/metabolismo , Vacinas Anticâncer/imunologia , Lactatos/metabolismo , Melanoma/metabolismo , Receptor de Morte Celular Programada 1/imunologia , Linfócitos T Reguladores/fisiologia , Homólogo AlkB 5 da RNA Desmetilase/genética , Anticorpos , Citocinas/genética , Citocinas/metabolismo , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Humanos , Melanoma/terapia , Metiltransferases/genética , Metiltransferases/metabolismo , Transportadores de Ácidos Monocarboxílicos/genética , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Células Supressoras Mieloides/fisiologia , Sítios de Splice de RNA , Processamento de RNA , Simportadores/genética , Simportadores/metabolismo , Transcriptoma , Microambiente Tumoral , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo
2.
Nat Commun ; 11(1): 3935, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32769979

RESUMO

GABAA/glycine-mediated neuronal inhibition critically depends on intracellular chloride (Cl-) concentration which is mainly regulated by the K+-Cl- co-transporter 2 (KCC2) in the adult central nervous system (CNS). KCC2 heterogeneity thus affects information processing across CNS areas. Here, we uncover a gradient in Cl- extrusion capacity across the superficial dorsal horn (SDH) of the spinal cord (laminae I-II: LI-LII), which remains concealed under low Cl- load. Under high Cl- load or heightened synaptic drive, lower Cl- extrusion is unveiled in LI, as expected from the gradient in KCC2 expression found across the SDH. Blocking TrkB receptors increases KCC2 in LI, pointing to differential constitutive TrkB activation across laminae. Higher Cl- lability in LI results in rapidly collapsing inhibition, and a form of activity-dependent synaptic plasticity expressed as a continuous facilitation of excitatory responses. The higher metaplasticity in LI as compared to LII differentially affects sensitization to thermal and mechanical input. Thus, inconspicuous heterogeneity of Cl- extrusion across laminae critically shapes plasticity for selective nociceptive modalities.


Assuntos
Sensibilização do Sistema Nervoso Central/fisiologia , Cloretos/metabolismo , Plasticidade Neuronal/fisiologia , Nociceptividade/fisiologia , Células do Corno Posterior/fisiologia , Animais , Células Cultivadas , Masculino , Glicoproteínas de Membrana/antagonistas & inibidores , Glicoproteínas de Membrana/metabolismo , Camundongos , Modelos Neurológicos , Optogenética , Cultura Primária de Células , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Ratos , Receptor trkB/antagonistas & inibidores , Receptor trkB/metabolismo , Simportadores/metabolismo
3.
Plant Mol Biol ; 103(4-5): 545-560, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32504260

RESUMO

KEY MESSAGE: OsGTγ-2, a trihelix transcription factor, is a positive regulator of rice responses to salt stress by regulating the expression of ion transporters. Salinity stress seriously restricts rice growth and yield. Trihelix transcription factors (GT factors) specifically bind to GT elements and play a diverse role in plant morphological development and responses to abiotic stresses. In our previous study, we found that the GT-1 element (GAAAAA) is a key element in the salinity-induced OsRAV2 promoter. Here, we identified a rice OsGTγ family member, OsGTγ-2, which directly interacted with the GT-1 element in the OsRAV2 promoter. OsGTγ-2 specifically targeted the nucleus, was mainly expressed in roots, sheathes, stems and seeds, and was induced by salinity, osmotic and oxidative stresses and abscisic acid (ABA). The seed germination rate, seedling growth and survival rate under salinity stress was improved in OsGTγ-2 overexpressing lines (PZmUbi::OsGTγ-2). In contrast, CRISPR/Cas9-mediated OsGTγ-2 knockout lines (osgtγ-2) showed salt-hypersensitive phenotypes. In response to salt stress, different Na+ and K+ acclamation patterns were observed in PZmUbi::OsGTγ-2 lines and osgtγ-2 plants were observed. The molecular mechanism of OsGTγ-2 in rice salt adaptation was also investigated. Several major genes responsible for ion transporting, such as the OsHKT2; 1, OsHKT1; 3 and OsNHX1 were transcriptionally regulated by OsGTγ-2. A subsequent yeast one-hybrid assay and EMSA indicated that OsGTγ-2 directly interacted with the promoters of OsHKT2; 1, OsNHX1 and OsHKT1; 3. Taken together, these results suggest that OsGTγ-2 is an important positive regulator involved in rice responses to salt stress and suggest a potential role for OsGTγ-2 in regulating salinity adaptation in rice.


Assuntos
Aclimatação/fisiologia , Proteínas de Ligação a DNA/metabolismo , Oryza/fisiologia , Estresse Salino/fisiologia , Tolerância ao Sal/genética , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Aclimatação/genética , Adaptação Fisiológica , Sistemas CRISPR-Cas , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/crescimento & desenvolvimento , Desenvolvimento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Salinidade , Plântula/genética , Sementes/metabolismo , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico/genética , Simportadores/metabolismo , Fatores de Transcrição/genética
4.
PLoS One ; 15(5): e0226472, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379828

RESUMO

The ParB-parS partition complexes that bacterial replicons use to ensure their faithful inheritance also find employment in visualization of DNA loci, as less intrusive alternatives to fluorescent repressor-operator systems. The ability of ParB molecules to interact via their N-terminal domains and to bind to non-specific DNA enables expansion of the initial complex to a size both functional in partition and, via fusion to fluorescent peptides, visible by light microscopy. We have investigated whether it is possible to dispense with the need to insert parS in the genomic locus of interest, by determining whether ParB fused to proteins that bind specifically to natural DNA sequences can still assemble visible complexes. In yeast cells, coproduction of fusions of ParB to a fluorescent peptide and to a TALE protein targeting an endogenous sequence did not yield visible foci; nor did any of several variants of these components. In E.coli, coproduction of fusions of SopB (F plasmid ParB) to fluorescent peptide, and to dCas9 together with specific guide RNAs, likewise yielded no foci. The result of coproducing analogous fusions of SopB proteins with distinct binding specificities was also negative. Our observations imply that in order to assemble higher order partition complexes, ParB proteins need specific activation through binding to their cognate parS sites.


Assuntos
Proteínas de Bactérias/metabolismo , Centrômero/química , Centrômero/metabolismo , DNA Bacteriano/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Sequência de Bases , Sítios de Ligação , Proteína 9 Associada à CRISPR , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Plasmídeos/genética , Ligação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Simportadores/genética , Simportadores/metabolismo
5.
Cancer Sci ; 111(7): 2349-2360, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32449280

RESUMO

Solute carrier family 12 member 5 (SLC12A5) has an oncogenic role in bladder urothelial carcinoma. The present study aimed to characterize the molecular mechanisms of SLC12A5 in bladder urothelial carcinoma pathogenesis. Functional assays identified that in bladder urothelial carcinoma SLC12A5 interacts with and stabilizes SOX18, and then upregulates matrix metalloproteinase 7 (MMP7). In vivo and in vitro assays were performed to confirm the effect of SLC12A5's interaction with SOX18 on MMP7-mediated bladder urothelial carcinoma progression. SLC12A5 was upregulated in human bladder tumors, and correlated with the poor survival of patients with bladder urothelial carcinoma tumor invasion and metastasis, promoted by SLC12A5 overexpression. We demonstrated that SLC12A5 interacted with SOX18, and then upregulated MMP7, thus enhancing tumor progression. Importantly, SLC12A5 expression correlated positively with SOX18 and MMP7 expression in bladder urothelial carcinoma. Furthermore, SLC12A5 expression was suppressed by miR-133a-3p. Ectopic expression of SLC12A5 partly abolished miR-133a-3p-mediated suppression of cell migration. SLC12A5-SOX18 complex-mediated upregulation on MMP7 was important in bladder urothelial carcinoma progression. The miR-133a-3p/SLC12A5/SOX18/MMP7 signaling axis was critical for progression, and provided an effective therapeutic approach against bladder urothelial carcinoma.


Assuntos
Regulação Neoplásica da Expressão Gênica , Metaloproteinase 7 da Matriz/genética , Fatores de Transcrição SOXF/metabolismo , Simportadores/metabolismo , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/metabolismo , Adulto , Idoso , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Progressão da Doença , Feminino , Humanos , Imuno-Histoquímica , Masculino , Metaloproteinase 7 da Matriz/metabolismo , Pessoa de Meia-Idade , Prognóstico , Ligação Proteica , Transdução de Sinais , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/patologia
6.
PLoS One ; 15(5): e0233863, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470053

RESUMO

Adaptive regulation of epithelial transporters to nutrient intake is essential to decrease energy costs of their synthesis and maintenance, however such regulation is understudied. Previously we demonstrated that the transport function of the basolateral amino acid uniporter LAT4 (Slc43a2) is increased by dephosphorylation of serine 274 (S274) and nearly abolished by dephosphorylation of serine 297 (S297) when expressed in Xenopus oocytes. Phosphorylation changes in the jejunum of food-entrained mice suggested an increase in LAT4 transport function during food expectation. Thus, we investigated further how phosphorylation, expression and localization of mouse intestinal LAT4 respond to food-entrained diurnal rhythm and dietary protein content. In mice entrained with 18% protein diet, LAT4 mRNA was not submitted to diurnal regulation, unlike mRNAs of luminal symporters and antiporters. Only in duodenum, LAT4 protein expression increased during food intake. Concurrently, S274 phosphorylation was decreased in all three small intestinal segments, whereas S297 phosphorylation was increased only in jejunum. Interestingly, during food intake, S274 phosphorylation was nearly absent in ileum and accompanied by strong phosphorylation of mTORC1 target S6. Entraining mice with 8% protein diet provoked a shift in jejunal LAT4 localization from the cell surface to intracellular stores and increased S274 phosphorylation in both jejunum and ileum during food anticipation, suggesting decreased transport function. In contrast, 40% dietary protein content led to increased LAT4 expression in jejunum and its internalization in ileum. Ex vivo treatments of isolated intestinal villi fraction demonstrated that S274 phosphorylation was stimulated by protein kinase A. Rapamycin-sensitive insulin treatment and amino acids increased S297 phosphorylation, suggesting that the response to food intake might be regulated via the insulin-mTORC1 pathway. Ghrelin, an oscillating orexigenic hormone, did not affect phosphorylation of intestinal LAT4. Overall, we show that phosphorylation, expression and localization of intestinal mouse LAT4 responds to diurnal and dietary stimuli in location-specific manner.


Assuntos
Sistema L de Transporte de Aminoácidos/metabolismo , Sistema y+ de Transporte de Aminoácidos/metabolismo , Ritmo Circadiano , Proteínas na Dieta/farmacologia , Alimentos , Intestinos/fisiologia , Aminoácidos/metabolismo , Animais , Antiporters/metabolismo , Ritmo Circadiano/efeitos dos fármacos , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Grelina/administração & dosagem , Grelina/farmacologia , Insulina/metabolismo , Intestino Delgado/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos Endogâmicos C57BL , Microvilosidades/efeitos dos fármacos , Microvilosidades/metabolismo , Fosforilação/efeitos dos fármacos , Fosfosserina/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Frações Subcelulares/metabolismo , Simportadores/metabolismo , Serina-Treonina Quinases TOR/metabolismo
7.
Plant Mol Biol ; 103(4-5): 561-580, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32405802

RESUMO

KEY MESSAGE: CmHKT1;1 selectively exports Na+ from plant cells. Upon NaCl stress, its expression increased in a salt-tolerant melon cultivar. Overexpression of CmHKT1;1 increased transgenic Arabidopsis salt tolerance through improved K+/Na+ balance. High-affinity K+ transporters (HKTs) are thought to be involved in reducing Na+ in plant shoots under salt stress and modulating salt tolerance, but their function in a moderately salt-tolerant species of melon (Cucumis melo L.) remains unclear. In this study, a Na+ transporter gene, CmHKT1;1 (GenBank accession number: MK986658), was isolated from melons based on genome data. The transcript of CmHKT1;1 was relatively more abundant in roots than in stems or leaves from melon seedlings. The tobacco transient expression system showed that CmHKT1;1 was plasma-membrane localized. Upon salt stress, CmHKT1;1 expression was more strongly upregulated in a salt-tolerant melon cultivar, 'Bingxuecui' (BXC) compared with a salt-sensitive cultivar, 'Yulu' (YL). Electrophysiological evidence demonstrated that CmHKT1;1 only transported Na+, rather than K+, when expressed in Xenopus laevis oocytes. Overexpression of CmHKT1;1 increased salt sensitivity in Saccharomyces cerevisiae and salt tolerance in Arabidopsis thaliana. Under NaCl treatments, transgenic Arabidopsis plants accumulated significantly lower concentrations of Na+ in shoots than wild type plants and showed a better K+/Na+ balance, leading to better Fv/Fm, root length, biomass, and enhanced plant growth. The CmHKT1;1 gene may serve as a useful candidate for improving crop salt tolerance.


Assuntos
Arabidopsis/metabolismo , Cucumis melo/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Potássio/metabolismo , Sódio/metabolismo , Arabidopsis/genética , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Clorofila/análise , Clonagem Molecular , Cucumis melo/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Membrana Transportadoras/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/genética , Saccharomyces cerevisiae/genética , Tolerância ao Sal , Plântula/genética , Plântula/metabolismo , Alinhamento de Sequência , Análise de Sequência de Proteína , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Simportadores/genética , Simportadores/metabolismo , Tabaco/genética , Tabaco/metabolismo
8.
PLoS One ; 15(5): e0232967, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32413057

RESUMO

The pivotal role of KCC2 and NKCC1 in development and maintenance of fast inhibitory neurotransmission and their implication in severe human diseases arouse interest in posttranscriptional regulatory mechanisms such as (de)phosphorylation. Staurosporine (broad kinase inhibitor) and N-ethylmalemide (NEM) that modulate kinase and phosphatase activities enhance KCC2 and decrease NKCC1 activity. Here, we investigated the regulatory mechanism for this reciprocal regulation by mass spectrometry and immunoblot analyses using phospho-specific antibodies. Our analyses revealed that application of staurosporine or NEM dephosphorylates Thr1007 of KCC2, and Thr203, Thr207 and Thr212 of NKCC1. Dephosphorylation of Thr1007 of KCC2, and Thr207 and Thr212 of NKCC1 were previously demonstrated to activate KCC2 and to inactivate NKCC1. In addition, application of the two agents resulted in dephosphorylation of the T-loop and S-loop phosphorylation sites Thr233 and Ser373 of SPAK, a critical kinase in the WNK-SPAK/OSR1 signaling module mediating phosphorylation of KCC2 and NKCC1. Taken together, these results suggest that reciprocal regulation of KCC2 and NKCC1 via staurosporine and NEM is based on WNK-SPAK/OSR1 signaling. The key regulatory phospho-site Ser940 of KCC2 is not critically involved in the enhanced activation of KCC2 upon staurosporine and NEM treatment, as both agents have opposite effects on its phosphorylation status. Finally, NEM acts in a tissue-specific manner on Ser940, as shown by comparative analysis in HEK293 cells and immature cultured hippocampal neurons. In summary, our analyses identified phospho-sites that are responsive to staurosporine or NEM application. This provides important information towards a better understanding of the cooperative interactions of different phospho-sites.


Assuntos
Etilmaleimida/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Membro 2 da Família 12 de Carreador de Soluto/metabolismo , Estaurosporina/farmacologia , Simportadores/metabolismo , Animais , Sítios de Ligação , Células Cultivadas , Células HEK293 , Hipocampo/citologia , Hipocampo/metabolismo , Humanos , Fosforilação/efeitos dos fármacos , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Proteínas Recombinantes/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transfecção , Proteína Quinase 1 Deficiente de Lisina WNK/metabolismo
9.
Ecotoxicol Environ Saf ; 196: 110544, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32251951

RESUMO

Thiazole-Zn is a systemic fungicide synthesized and developed in China that has been used for the prevention and treatment of bacterial and fungal diseases on fruits and vegetables. Thiazole-Zn is a new thyroid disruptor chemical. The purpose of this study was to clarify the thyroid-disrupting property of thiazole-Zn and the mechanism responsible for thyroid hormone (TH) biosynthesis inhibition in male rats induced by thiazole-Zn. First, the effects of different thiazole-Zn doses and exposure times on the thyroid weights, thyroid morphology and serum hormone levels of rats were investigated. The results showed that thiazole-Zn increased thyroid weights and serum thyroid-stimulating hormone (TSH) levels and induced thyroid cell hypertrophy and hyperplasia in a dose-related and time-related manner. Furthermore, measurement of thyroid radioiodine uptake in vivo in rats confirmed that thiazole-Zn inhibited active iodide uptake into the thyroid, which reduced circulating levels of serum T3 and T4. Decreases in circulating THs resulted in a compensatory increase in serum TSH levels through a negative feedback system. Subsequently, sustained excessive stimulation of the thyroid gland by TSH led to thyroid follicular cell hypertrophy and hyperplasia. In addition, thiazole-Zn increased sodium/iodide symporter (NIS) expression in the rat thyroid, and the increased NIS expression promoted and restored iodide uptake into the thyroids of rats. The risk of iodine intake inhibition by thiazole-Zn to humans, especially susceptible individuals, such as children and pregnant women, warrants additional attention.


Assuntos
Complexos de Coordenação/toxicidade , Fungicidas Industriais/toxicidade , Tiadiazóis/toxicidade , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/patologia , Animais , China , Hiperplasia , Hipertrofia , Iodo/metabolismo , Radioisótopos do Iodo , Masculino , Ratos , Ratos Sprague-Dawley , Simportadores/metabolismo , Glândula Tireoide/metabolismo , Hormônios Tireóideos/sangue , Tireotropina/sangue
10.
Clin Nucl Med ; 45(5): e243-e244, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32149814

RESUMO

Management of patients with thyroglobulin elevated and negative iodine scan is still a challenge with limited options left as the disease stops concentrating iodine. The minimally invasive surgery is the best option for residual/recurrent locoregional disease in postsurgical setup requiring accurate presurgical localization. Intraoperative gamma probe using low-dose tracer has shown its utility in radioguided surgery. The authors present a 46-year-old man with thyroglobulin elevated and negative iodine scan showing FDG-avid left supraclavicular lymph node on whole-body F-FDG PET/CT with physiological uptake on whole-body radioactive iodine scan, where Tc-MIBI radioguided probe helped in carrying out minimally invasive surgery with excision of malignant node.


Assuntos
Cirurgia Assistida por Computador , Tecnécio Tc 99m Sestamibi , Tireoglobulina/metabolismo , Regulação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Simportadores/metabolismo , Imagem Corporal Total
11.
Gene ; 742: 144569, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32165301

RESUMO

The nuclear factor of activated T-cells 5 (NFAT5), also known as tonicity-responsive enhancer-binding protein (TonEBP), is a transcription factor that regulates osmoadaptive response in multiple tissues and is highly expressed in the developing central nervous system. A former study reported that NFAT5 activation through hypertonic stress increases the expression of the dopa decarboxylase enzyme (DDC), also known as aromatic-l-amino-acid decarboxylase (AADC), in human renal proximal tubule cells, leading to an increase of dopamine synthesis. In a previous study, we identified NFAT5 as a candidate gene for cocaine dependence, a complex psychiatric disorder in which dopaminergic neurotransmission plays an important role. Therefore, to test the hypothesis that NFAT5 may also affect dopamine levels in the nervous system through the regulation of DDC expression, we examined this regulation using two neural dopaminergic cell lines, SH-SY5Y and PC12. The effect of NFAT5 on the expression of the neuronal isoform of DDC was evaluated by qRT-PCR. Upon hypertonic stress, NFAT5 was activated and accumulated into the nuclei and, subsequently, the expression of NFAT5 and its known targets sodium/myo-inositol cotransporter 1 (SMIT) and sodium chloride/taurine cotransporter (TAUT) increased, as expected. However, the expression of DDC decreased. When silencing the expression of NFAT5 with a specific shRNA we observed that the downregulation of DDC is independent from NFAT5 in both cell lines and is due to hypertonic stress. In conclusion, NFAT5 does not regulate the expression of the neuronal isoform of DDC in neural dopaminergic cell lines and, consequently, it does not modulate dopamine synthesis through DDC.


Assuntos
Descarboxilases de Aminoácido-L-Aromático/genética , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Fatores de Transcrição/metabolismo , Animais , Descarboxilases de Aminoácido-L-Aromático/metabolismo , Linhagem Celular Tumoral , Regulação para Baixo , Proteínas de Choque Térmico/metabolismo , Humanos , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Pressão Osmótica , RNA Interferente Pequeno/metabolismo , Ratos , Simportadores/metabolismo , Fatores de Transcrição/genética , Regulação para Cima
12.
Nat Chem Biol ; 16(4): 469-478, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32152546

RESUMO

Solute carriers (SLCs) are the largest family of transmembrane transporters in humans and are major determinants of cellular metabolism. Several SLCs have been shown to be required for the uptake of chemical compounds into cellular systems, but systematic surveys of transporter-drug relationships in human cells are currently lacking. We performed a series of genetic screens in a haploid human cell line against 60 cytotoxic compounds representative of the chemical space populated by approved drugs. By using an SLC-focused CRISPR-Cas9 library, we identified transporters whose absence induced resistance to the drugs tested. This included dependencies involving the transporters SLC11A2/SLC16A1 for artemisinin derivatives and SLC35A2/SLC38A5 for cisplatin. The functional dependence on SLCs observed for a significant proportion of the screened compounds suggests a widespread role for SLCs in the uptake and cellular activity of cytotoxic drugs and provides an experimentally validated set of SLC-drug associations for a number of clinically relevant compounds.


Assuntos
Resistência a Medicamentos/genética , Proteínas Carreadoras de Solutos/metabolismo , Sistemas de Transporte de Aminoácidos Neutros/genética , Sistemas de Transporte de Aminoácidos Neutros/metabolismo , Antineoplásicos , Fenômenos Bioquímicos , Transporte Biológico/genética , Transporte Biológico/fisiologia , Sistemas CRISPR-Cas , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Resistência a Medicamentos/fisiologia , Testes Genéticos , Humanos , Transportadores de Ácidos Monocarboxílicos/genética , Transportadores de Ácidos Monocarboxílicos/metabolismo , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Transporte Proteico/fisiologia , Proteínas Carreadoras de Solutos/fisiologia , Simportadores/genética , Simportadores/metabolismo
13.
J Med Chem ; 63(4): 1717-1723, 2020 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-32026684

RESUMO

Iodide homeostasis and thyroid hormone metabolism in the brain are potentially related to changes in the activity of the sodium iodide symporter (NIS). No radiotracers are currently available for imaging brain NIS activity. Here, we synthesized 6-[124I]iodo-9-pentylpurine that can noninvasively measure iodide efflux from the brain and showed that the efflux rate of [124I]I- in NIS knockout mice was 84% lower than that of wild-type mice. Thus, 6-[124I]iodo-9-pentylpurine would be useful for imaging brain NIS activity.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Purinas/farmacologia , Compostos Radiofarmacêuticos/farmacologia , Simportadores/metabolismo , Animais , Iodetos/metabolismo , Radioisótopos do Iodo/química , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Tomografia por Emissão de Pósitrons , Purinas/síntese química , Purinas/farmacocinética , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/farmacocinética , Simportadores/genética
14.
Artigo em Inglês | MEDLINE | ID: mdl-32044673

RESUMO

Grapevine (Vitis vinifera L.) is a valuable crop for human consumption and wine production, and is prone to suffering from salinity stress in arid regions or when exposed to low quality irrigation water. A previous study identified a quantitative trait locus (QTL) NaE, containing six High-affinity Potassium Transporter 1 genes, that was associated with shoot Na+ exclusion in grapevine. While HKT1;1 was predicted to be the most likely gene within this QTL to encode for this important salinity tolerance sub-trait, four other HKTs within the QTL remained uncharacterised; VviHKT1;2 encodes a truncated transcript unlikely to form a functional transporter. In this study, two allelic variants for each of VviHKT1;6, VviHKT1;7 and VviHKT1;8 from the heterozygous grapevine variety Cabernet Sauvignon were functionally characterised. Using the Xenopus laevis oocyte heterologous expression system, as well as transient expression in tobacco leaves, we found that the VviHKT1;6 and VviHKT1;7 alleles encoded plasma membrane localised proteins that facilitated significant non-rectifying Na+ transport. Conversely, proteins encoded by the VviHKT1;8 alleles were inwardly-rectifying, weak Na+ transporters that localised to intracellular organelles. Mining of previous RNA-seq gene expression data suggested that VviHKT1;6-8 are weakly expressed in grapevine roots, flower buds, and seeds under normal conditions and different nutrient regimes. We propose that VviHKT1;6 and VviHKT1;7 are likely to have a less significant role in grapevine leaf Na+ exclusion than VviHKT1;1, and that VviHKT1;8 is involved in endomembrane Na+ transport.


Assuntos
Proteínas de Transporte de Cátions/genética , Proteínas de Plantas/genética , Brotos de Planta/metabolismo , Locos de Características Quantitativas , Sódio/metabolismo , Simportadores/genética , Vitis/genética , Animais , Transporte Biológico , Proteínas de Transporte de Cátions/metabolismo , Membrana Celular/metabolismo , Oócitos , Proteínas de Plantas/metabolismo , Simportadores/metabolismo , Vitis/metabolismo , Xenopus
15.
Nat Commun ; 11(1): 869, 2020 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-32054836

RESUMO

Spinal disinhibition has been hypothesized to underlie pain hypersensitivity in neuropathic pain. Apparently contradictory mechanisms have been reported, raising questions on the best target to produce analgesia. Here, we show that nerve injury is associated with a reduction in the number of inhibitory synapses in the spinal dorsal horn. Paradoxically, this is accompanied by a BDNF-TrkB-mediated upregulation of synaptic GABAARs and by an α1-to-α2GABAAR subunit switch, providing a mechanistic rationale for the analgesic action of the α2,3GABAAR benzodiazepine-site ligand L838,417 after nerve injury. Yet, we demonstrate that impaired Cl- extrusion underlies the failure of L838,417 to induce analgesia at high doses due to a resulting collapse in Cl- gradient, dramatically limiting the benzodiazepine therapeutic window. In turn, enhancing KCC2 activity not only potentiated L838,417-induced analgesia, it rescued its analgesic potential at high doses, revealing a novel strategy for analgesia in pathological pain, by combined targeting of the appropriate GABAAR-subtypes and restoring Cl- homeostasis.


Assuntos
Analgésicos/farmacologia , Cloretos/metabolismo , Neuralgia/tratamento farmacológico , Neuralgia/fisiopatologia , Receptores de GABA-A/fisiologia , Analgesia/métodos , Analgésicos/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Modelos Animais de Doenças , Fluorbenzenos/metabolismo , Fluorbenzenos/farmacologia , Agonistas de Receptores de GABA-A/farmacologia , Transporte de Íons/efeitos dos fármacos , Ligantes , Masculino , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Traumatismos dos Nervos Periféricos/patologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Ratos , Ratos Sprague-Dawley , Receptor trkB/metabolismo , Simportadores/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Triazóis/metabolismo , Triazóis/farmacologia
16.
PLoS One ; 15(2): e0229085, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084174

RESUMO

The sodium iodide symporter (NIS) transports iodide, which is necessary for thyroid hormone production. NIS also transports other monovalent anions such as tetrafluoroborate (BF4-), pertechnetate (TcO4-), and thiocyanate (SCN-), and is competitively inhibited by perchlorate (ClO4-). However, the mechanisms of substrate selectivity and inhibitor sensitivity are poorly understood. Here, a comparative approach was taken to determine whether naturally evolved NIS proteins exhibit variability in their substrate transport properties. The NIS proteins of thirteen animal species were initially assessed, and three species from environments with differing iodide availability, freshwater species Danio rerio (zebrafish), saltwater species Balaenoptera acutorostrata scammoni (minke whale), and non-aquatic mammalian species Homo sapiens (human) were studied in detail. NIS genes from each of these species were lentivirally transduced into HeLa cells, which were then characterized using radioisotope uptake assays, 125I- competitive substrate uptake assays, and kinetic assays. Homology models of human, minke whale and zebrafish NIS were used to evaluate sequence-dependent impact on the organization of Na+ and I- binding pockets. Whereas each of the three proteins that were analyzed in detail concentrated iodide to a similar degree, their sensitivity to perchlorate inhibition varied significantly: minke whale NIS was the least impacted by perchlorate inhibition (IC50 = 4.599 µM), zebrafish NIS was highly sensitive (IC50 = 0.081 µM), and human NIS showed intermediate sensitivity (IC50 = 1.566 µM). Further studies with fifteen additional substrates and inhibitors revealed similar patterns of iodide uptake inhibition, though the degree of 125I- uptake inhibition varied with each compound. Kinetic analysis revealed whale NIS had the lowest Km-I and the highest Vmax-I. Conversely, zebrafish NIS had the highest Km and lowest Vmax. Again, human NIS was intermediate. Molecular modeling revealed a high degree of conservation in the putative ion binding pockets of NIS proteins from different species, which suggests the residues responsible for the observed differences in substrate selectivity lie elsewhere in the protein. Ongoing studies are focusing on residues in the extracellular loops of NIS as determinants of anion specificity. These data demonstrate significant transport differences between the NIS proteins of different species, which may be influenced by the unique physiological needs of each organism. Our results also identify naturally-existing NIS proteins with significant variability in substrate transport kinetics and inhibitor sensitivity, which suggest that the affinity and selectivity of NIS for certain substrates can be altered for biotechnological and clinical applications. Further examination of interspecies differences may improve understanding of the substrate transport mechanism.


Assuntos
Boratos/metabolismo , Animais , Linhagem Celular , Células HeLa , Humanos , Cinética , Lentivirus/genética , Percloratos/metabolismo , Simportadores/metabolismo , Tiocianatos/metabolismo , Baleias , Peixe-Zebra
17.
Plant Mol Biol ; 102(6): 603-614, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32052233

RESUMO

The WRKY transcription factor family is involved in responding to biotic and abiotic stresses. Its members contain a typical WRKY domain and can regulate plant physiological responses by binding to W-boxes in the promoter regions of downstream target genes. We identified the sweet sorghum SbWRKY50 (Sb09g005700) gene, which encodes a typical class II of the WRKY family protein that localizes to the nucleus and has transcriptional activation activity. The expression of SbWRKY50 in sweet sorghum was reduced by salt stress, and its ectopic expression reduced the salt tolerance of Arabidopsis thaliana plants. Compared with the wild type, the germination rate, root length, biomass and potassium ion content of SbWRKY50 over-expression plants decreased significantly under salt-stress conditions, while the hydrogen peroxide, superoxide anion and sodium ion contents increased. Real-time PCR results showed that the expression levels of AtSOS1, AtHKT1 and genes related to osmotic and oxidative stresses in over-expression strains decreased under salt-stress conditions. Luciferase complementation imaging and yeast one-hybrid assays confirmed that SbWRKY50 could directly bind to the upstream promoter of the SOS1 gene in A. thaliana. However, in sweet sorghum, SbWRKY50 could directly bind to the upstream promoters of SOS1 and HKT1. These results suggest that the new WRKY transcription factor SbWRKY50 participates in plant salt response by controlling ion homeostasis. However, the regulatory mechanisms are different in sweet sorghum and Arabidopsis, which may explain their different salt tolerance levels. The data provide information that can be applied to genetically modifying salt tolerance in different crop varieties.


Assuntos
Homeostase , Tolerância ao Sal/fisiologia , Sorghum/genética , Sorghum/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Biomassa , Proteínas de Transporte , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação , Peróxido de Hidrogênio/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Potássio/metabolismo , Regiões Promotoras Genéticas , Espécies Reativas de Oxigênio/metabolismo , Sementes , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico , Superóxidos/metabolismo , Simportadores/genética , Simportadores/metabolismo
18.
Invest Ophthalmol Vis Sci ; 61(2): 7, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32031579

RESUMO

Purpose: Confirm that the corneal endothelial pump uses a lactate-coupled water efflux mechanism. Methods: Corneal thickness, lactate efflux, and stromal [lactate] were measured in de-epithelialized swollen and nonswollen ex vivo-mounted rabbit corneas perfused with bicarbonate-rich and bicarbonate-free Ringers, ouabain, or acetazolamide to determine if the relationships among these parameters were similar to previous data using intact corneas. The role of barrier function was tested by perfusion with calcium-free EGTA. Predictions of [lactate] in endothelial dystrophy were examined in the Slc4a11 knock out mouse. Results: De-epithelialized corneal swelling, lactate efflux, and stromal [lactate] in response to bicarbonate-free Ringers, ouabain, and acetazolamide perfusion had the same relationship as in intact corneas. The absolute amount of lactate efflux and stromal [lactate] in the de-epithelialized corneas was about half of intact corneas. De-epithelialized, swollen corneas deswelled fully with bicarbonate-rich, partially in the presence of acetazolamide, but continued to swell with bicarbonate-free or ouabain. The relationship among corneal thickness, lactate efflux, and [lactate] was the same as with nonswollen de-epithelialized corneas. In intact corneas swollen by perfusion with calcium-free EGTA, the relationship between swelling and lactate flux was the inverse of control corneas. The relationship between corneal swelling and [lactate] of intact corneas exposed to ouabain, but perfused with 7 mM lactate to simulate aqueous humor, was the same as without lactate. Corneal [lactate] in Slc4a11 knock out was twice that of wild type. Conclusions: The corneal endothelial pump works via a lactate efflux mechanism that requires an intact osmotic barrier.


Assuntos
Epitélio Posterior/metabolismo , Ácido Láctico/metabolismo , Animais , Proteínas de Transporte de Ânions/metabolismo , Transporte Biológico Ativo/fisiologia , Córnea/metabolismo , Edema da Córnea/fisiopatologia , Inibidores Enzimáticos/farmacologia , Feminino , Masculino , Camundongos Knockout , Ouabaína/farmacologia , Coelhos , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Simportadores/metabolismo
19.
Nat Commun ; 11(1): 998, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081874

RESUMO

Glutamate transporters are cation-coupled secondary active membrane transporters that clear the neurotransmitter L-glutamate from the synaptic cleft. These transporters are homotrimers, with each protomer functioning independently by an elevator-type mechanism, in which a mobile transport domain alternates between inward- and outward-oriented states. Using single-particle cryo-EM we have determined five structures of the glutamate transporter homologue GltTk, a Na+- L-aspartate symporter, embedded in lipid nanodiscs. Dependent on the substrate concentrations used, the protomers of the trimer adopt a variety of asymmetrical conformations, consistent with the independent movement. Six of the 15 resolved protomers are in a hitherto elusive state of the transport cycle in which the inward-facing transporters are loaded with Na+ ions. These structures explain how substrate-leakage is prevented - a strict requirement for coupled transport. The belt protein of the lipid nanodiscs bends around the inward oriented protomers, suggesting that membrane deformations occur during transport.


Assuntos
Sistema X-AG de Transporte de Aminoácidos/química , Proteínas Arqueais/química , Sistema X-AG de Transporte de Aminoácidos/genética , Sistema X-AG de Transporte de Aminoácidos/metabolismo , Proteínas Arqueais/genética , Proteínas Arqueais/metabolismo , Ácido Aspártico/metabolismo , Sítios de Ligação , Microscopia Crioeletrônica , Lipídeos/química , Modelos Moleculares , Nanoestruturas/química , Conformação Proteica , Estrutura Quaternária de Proteína , Pyrococcus horikoshii/metabolismo , Imagem Individual de Molécula , Simportadores/química , Simportadores/metabolismo , Thermococcus/genética , Thermococcus/metabolismo
20.
Int J Oncol ; 56(2): 460-469, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31894266

RESUMO

Gastric cancer (GC) is one of the leading causes of malignancy­associated mortality worldwide. However, the underlying molecular mechanisms of GC are unclear and the prognosis of GC is poor. Therefore, it is important and urgent to explore the underlying mechanisms and screen for novel diagnostic and prognostic biomarkers, as well as therapeutic targets. In the current study, scale­free gene co­expression networks were constructed using weighted gene co­expression network analysis, the potential associations between gene sets and clinical features were investigated, and the hub genes were identified. The gene expression profiles of GSE38749 were downloaded from the Gene Expression Omnibus database. RNA­seq and clinical data for GC from The Cancer Genome Atlas were utilized for verification. Furthermore, the expression of candidate biomarkers in gastric tissues was investigated. Survival analysis was performed using Kaplan­Meier and log­rank test. The predictive role of candidate biomarkers in GC was evaluated using a receiver operator characteristic (ROC) curve. Gene Ontology, gene set enrichment analysis and gene set variation analysis methods were used to interpret the function of candidate biomarkers in GC. A total of 29 modules were identified via the average linkage hierarchical clustering. A significant module consisting of 48 genes associated with clinical traits was found; three genes with high connectivity in the clinical significant module were identified as hub genes. Among them, SLC5A6 and microfibril­associated protein 2 (MFAP2) were negatively associated with the overall survival, and their expression was elevated in GC compared with non­tumor tissues. Additionally, ROC curves indicated that SLC5A6 and MFAP2 showed a good diagnostic power in discriminating cancerous from normal tissues. SLC5A6 and MFAP2 were identified as novel diagnostic and prognostic biomarkers in GC patients; both of these genes were first reported here in connection with GC and deserved further research.


Assuntos
Biomarcadores Tumorais/análise , Fatores de Processamento de RNA/análise , Neoplasias Gástricas/diagnóstico , Simportadores/análise , Biomarcadores Tumorais/metabolismo , Conjuntos de Dados como Assunto , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Imuno-Histoquímica , Prognóstico , Fatores de Processamento de RNA/metabolismo , RNA-Seq , Curva ROC , Estômago/patologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologia , Análise de Sobrevida , Simportadores/metabolismo , Fatores de Tempo
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