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1.
Diabetes ; 71(2): 285-297, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34753800

RESUMO

Red blood cells (RBC) act as mediators of vascular injury in type 2 diabetes mellitus (T2DM). miR-210 plays a protective role in cardiovascular homeostasis and is decreased in whole blood of T2DM mice. We hypothesized that downregulation of RBC miR-210 induces endothelial dysfunction in T2DM. RBC were coincubated with arteries and endothelial cells ex vivo and transfused in vivo to identify the role of miR-210 and its target protein tyrosine phosphatase 1B (PTP1B) in endothelial dysfunction. RBC from patients with T2DM and diabetic rodents induced endothelial dysfunction ex vivo and in vivo. miR-210 levels were lower in human RBC from patients with T2DM (T2DM RBC) than in RBC from healthy subjects. Transfection of miR-210 in human T2DM RBC rescued endothelial function, whereas miR-210 inhibition in healthy subjects RBC or RBC from miR-210 knockout mice impaired endothelial function. Human T2DM RBC decreased miR-210 expression in endothelial cells. miR-210 expression in carotid artery plaques was lower in T2DM patients than in patients without diabetes. Endothelial dysfunction induced by downregulated RBC miR-210 involved PTP1B and reactive oxygen species. miR-210 mimic attenuated endothelial dysfunction induced by RBC via downregulating vascular PTP1B and oxidative stress in diabetic mice in vivo. These data reveal that the downregulation of RBC miR-210 is a novel mechanism driving the development of endothelial dysfunction in T2DM.


Assuntos
Diabetes Mellitus Tipo 2 , Endotélio Vascular/fisiopatologia , Eritrócitos/metabolismo , MicroRNAs/genética , Animais , Estudos de Casos e Controles , Células Cultivadas , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatologia , Angiopatias Diabéticas/sangue , Angiopatias Diabéticas/genética , Angiopatias Diabéticas/metabolismo , Angiopatias Diabéticas/fisiopatologia , Endotélio Vascular/metabolismo , Humanos , Masculino , Camundongos , Camundongos Knockout , MicroRNAs/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo
2.
Endocrinology ; 163(2)2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34967909

RESUMO

Reproductive dysfunction in women has been linked to high caloric diet (HCD)-feeding and obesity. Central resistance to leptin and insulin have been shown to accompany diet-induced infertility in rodent studies, and we have previously shown that deleting suppressor of cytokine signaling 3, which is a negative regulator of leptin signaling, from all forebrain neurons partially protects mice from HCD-induced infertility. In this study, we were interested in exploring the role of protein tyrosine phosphatase 1B (PTP1B), which is a negative regulator of both leptin and insulin signaling, in the pathophysiology of HCD-induced obesity and infertility. To this end, we generated male and female neuron-specific PTP1B knockout mice and compared their body weight gain, food intake, glucose tolerance, and fertility relative to control littermates under both normal calorie diet and HCD feeding conditions. Both male and female mice with neuronal PTP1B deletion exhibited slower body weight gain in response to HCD feeding, yet only male knockout mice exhibited improved glucose tolerance compared with controls. Neuronal PTP1B deletion improved the time to first litter in HCD-fed mice but did not protect female mice from eventual HCD-induced infertility. While the mice fed a normal caloric diet remained fertile throughout the 150-day period of assessment, HCD-fed females became infertile after producing only a single litter, regardless of their genotype. These data show that neuronal PTP1B deletion is able to partially protect mice from HCD-induced obesity but is not a critical mediator of HCD-induced infertility.


Assuntos
Encéfalo/enzimologia , Infertilidade Feminina/prevenção & controle , Neurônios/enzimologia , Obesidade/prevenção & controle , Proteína Tirosina Fosfatase não Receptora Tipo 1/deficiência , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Animais , Cruzamentos Genéticos , Ingestão de Energia , Feminino , Infertilidade Feminina/etiologia , Masculino , Camundongos Endogâmicos DBA , Camundongos Knockout , Camundongos Transgênicos , Obesidade/enzimologia , Obesidade/etiologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , Maturidade Sexual
3.
Life Sci Alliance ; 4(11)2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34526379

RESUMO

B cell antigen receptor (BCR) signaling is initiated by protein kinases and limited by counteracting phosphatases that currently are less well studied in their regulation of BCR signaling. Here, we used the B cell line Ramos to identify and quantify human B cell signaling components. Specifically, a protein tyrosine phosphatase profiling revealed a high expression of the protein tyrosine phosphatase 1B (PTP1B) in Ramos and human naïve B cells. The loss of PTP1B leads to increased B cell activation. Through substrate trapping in combination with quantitative mass spectrometry, we identified 22 putative substrates or interactors of PTP1B. We validated Igα, CD22, PLCγ1/2, CBL, BCAP, and APLP2 as specific substrates of PTP1B in Ramos B cells. The tyrosine kinase BTK and the two adaptor proteins GRB2 and VAV1 were identified as direct binding partners and potential substrates of PTP1B. We showed that PTP1B dephosphorylates the inhibitory receptor protein CD22 at phosphotyrosine 807. We conclude that PTP1B negatively modulates BCR signaling by dephosphorylating distinct phosphotyrosines in B cell-specific receptor proteins and various downstream signaling components.


Assuntos
Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Linfócitos B/metabolismo , Linhagem Celular , Proteína Adaptadora GRB2/metabolismo , Espectrometria de Massas/métodos , Fosforilação , Ligação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Proteínas Tirosina Quinases/metabolismo , Proteômica/métodos , Proteínas Proto-Oncogênicas c-vav/metabolismo , Receptores de Antígenos de Linfócitos B/fisiologia , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismo , Transdução de Sinais/genética
4.
Int J Mol Sci ; 22(9)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33947152

RESUMO

Previously, we have revealed that the miR-130 family (miR-130b, miR-301a, and miR-301b) functions as an oncomiR in bladder cancer. The pharmacological inhibition of the miR-130 family molecules by the seed-targeting strategy with an 8-mer tiny locked nucleic acid (LNA) inhibits the growth, migration, and invasion of bladder cancer cells by repressing stress fiber formation. Here, we searched for a functionally advanced target sequence with LNA for the miR-130 family with low cytotoxicity and found LNA #9 (A(L)^i^i^A(L)^T(L)^T(L)^G(L)^5(L)^A(L)^5(L)^T(L)^G) as a candidate LNA. LNA #9 inhibited cell growth in vitro and in an in vivo orthotopic bladder cancer model. Proteome-wide tyrosine phosphorylation analysis suggested that the miR-130 family upregulates a wide range of receptor tyrosine kinases (RTKs) signaling via the expression of phosphorylated Src (pSrcTyr416). SILAC-based proteome analysis and a luciferase assay identified protein tyrosine phosphatase non-receptor type 1 (PTPN1), which is implicated as a negative regulator of multiple signaling pathways downstream of RTKs as a target gene of the miR-130 family. The miR-130-targeted LNA increased and decreased PTPN1 and pSrcTyr416 expressions, respectively. PTPN1 knockdown led to increased tumor properties (cell growth, invasion, and migration) and increased pSrcTyr416 expression in bladder cancer cells, suggesting that the miR-130 family upregulates multiple RTK signaling by targeting PTPN1 and subsequent Src activation in bladder cancer. Thus, our newly designed miR-130 family targeting LNA could be a promising nucleic acid therapeutic agent for bladder cancer.


Assuntos
Antineoplásicos/uso terapêutico , MicroRNAs/antagonistas & inibidores , Proteínas de Neoplasias/fisiologia , Oligonucleotídeos/uso terapêutico , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , RNA Neoplásico/antagonistas & inibidores , Neoplasias da Bexiga Urinária/tratamento farmacológico , Animais , Carcinoma de Células de Transição/tratamento farmacológico , Carcinoma de Células de Transição/genética , Carcinoma de Células de Transição/metabolismo , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Regulação Neoplásica da Expressão Gênica , Genes Reporter , Humanos , Camundongos , MicroRNAs/genética , RNA Neoplásico/genética , Receptores Proteína Tirosina Quinases/biossíntese , Receptores Proteína Tirosina Quinases/genética , Proteínas Recombinantes/metabolismo , Regulação para Cima , Neoplasias da Bexiga Urinária/genética , Neoplasias da Bexiga Urinária/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
5.
J Neurosci ; 40(7): 1581-1593, 2020 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-31915254

RESUMO

Alzheimer's disease (AD) is the most common neurodegenerative disorder, resulting in the progressive decline of cognitive function in patients. Familial forms of AD are tied to mutations in the amyloid precursor protein, but the cellular mechanisms that cause AD remain unclear. Inflammation and amyloidosis from amyloid ß (Aß) aggregates are implicated in neuron loss and cognitive decline. Inflammation activates the protein-tyrosine phosphatase 1B (PTP1B), and this could suppress many signaling pathways that activate glycogen synthase kinase 3ß (GSK3ß) implicated in neurodegeneration. However, the significance of PTP1B in AD pathology remains unclear. Here, we show that pharmacological inhibition of PTP1B with trodusquemine or selective ablation of PTP1B in neurons prevents hippocampal neuron loss and spatial memory deficits in a transgenic AD mouse model with Aß pathology (hAPP-J20 mice of both sexes). Intriguingly, while systemic inhibition of PTP1B reduced inflammation in the hippocampus, neuronal PTP1B ablation did not. These results dissociate inflammation from neuronal loss and cognitive decline and demonstrate that neuronal PTP1B hastens neurodegeneration and cognitive decline in this model of AD. The protective effect of PTP1B inhibition or ablation coincides with the restoration of GSK3ß inhibition. Neuronal ablation of PTP1B did not affect cerebral amyloid levels or plaque numbers, but reduced Aß plaque size in the hippocampus. In summary, our preclinical study suggests that targeting PTP1B may be a new strategy to intervene in the progression of AD.SIGNIFICANCE STATEMENT Familial forms of Alzheimer's disease (AD) are tied to mutations in the amyloid precursor protein, but the cellular mechanisms that cause AD remain unclear. Here, we used a mouse model expressing human amyloid precursor protein bearing two familial mutations and asked whether activation of a phosphatase PTP1B participates in the disease process. Systemic inhibition of this phosphatase using a selective inhibitor prevented cognitive decline, neuron loss in the hippocampus, and attenuated inflammation. Importantly, neuron-targeted ablation of PTP1B also prevented cognitive decline and neuron loss but did not reduce inflammation. Therefore, neuronal loss rather than inflammation was critical for AD progression in this mouse model, and that disease progression could be ameliorated by inhibition of PTP1B.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Proteínas do Tecido Nervoso/fisiologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Memória Espacial/fisiologia , Peptídeos beta-Amiloides/análise , Animais , Colestanos/farmacologia , Modelos Animais de Doenças , Feminino , Glicogênio Sintase Quinase 3 beta/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Humanos , Inflamação , Resistência à Insulina , Masculino , Aprendizagem em Labirinto , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Proteínas do Tecido Nervoso/antagonistas & inibidores , Fragmentos de Peptídeos/análise , Placa Amiloide/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Proteínas Recombinantes/metabolismo , Memória Espacial/efeitos dos fármacos , Espermina/análogos & derivados , Espermina/farmacologia
6.
Curr Mol Pharmacol ; 13(1): 17-30, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31339082

RESUMO

BACKGROUND: Protein tyrosine phosphatases are enzymes which help in the signal transduction in diabetes, obesity, cancer, liver diseases and neurodegenerative diseases. PTP1B is the main member of this enzyme from the protein extract of human placenta. In phosphate inhibitors development, significant progress has been made over the last 10 years. In early-stage clinical trials, few compounds have reached whereas in the later stage trials or registration, yet none have progressed. Many researchers investigate different ways to improve the pharmacological properties of PTP1B inhibitors. OBJECTIVE: In the present review, authors have summarized various aspects related to the involvement of PTP1B in various types of signal transduction mechanisms and its prominent role in various diseases like cancer, liver diseases and diabetes mellitus. CONCLUSION: There are still certain challenges for the selection of PTP1B as a drug target. Therefore, continuous future efforts are required to explore this target for the development of PTP inhibitors to treat the prevailing diseases associated with it.


Assuntos
Inibidores Enzimáticos/farmacologia , Terapia de Alvo Molecular , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Animais , Antineoplásicos/uso terapêutico , Diabetes Mellitus/tratamento farmacológico , Diabetes Mellitus/enzimologia , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacocinética , Inibidores Enzimáticos/uso terapêutico , Feminino , Previsões , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/fisiologia , Leptina/fisiologia , Camundongos , Modelos Moleculares , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Doenças Neurodegenerativas/tratamento farmacológico , Doenças Neurodegenerativas/enzimologia , Fármacos Neuroprotetores/uso terapêutico , Placenta/enzimologia , Gravidez , Conformação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 1/química , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Transdução de Sinais/efeitos dos fármacos
7.
Yakugaku Zasshi ; 139(5): 663-672, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31061333

RESUMO

Marine environments offer a rich source of natural products with potential therapeutic applications because the ocean covers 70% of the earth's surface and approximately 80% of all living organisms live in the sea. Therefore we have investigated bioactive compounds from marine organisms such as marine sponges, ascidians, and marine-derived microorganisms. This review consists of two topics based on marine natural product chemistry. (1) Protein tyrosine phosphatase (PTP) 1B plays a key role as a negative regulator in the insulin and leptin signaling pathways. Accordingly, the development of PTP1B inhibitors is expected to provide new drugs for type 2 diabetes and obesity. We have been searching for new types of PTP1B inhibitors among marine organisms and identified various PTP1B inhibitors from marine sponges and fungi. This review presents their structural diversities and unique biological properties. (2) In the course of our studies on the induced production of new fungal metabolites, the Palauan marine-derived fungus, Trichoderma cf. brevicompactum TPU199, was found to produce the unusual epipolythiodiketopiperazines, gliovirin and pretrichodermamide A. Long-term static fermentation of the strain induced production of a new dipeptide, dithioaspergillazine A, whereas fermentation of the strain with NaCl, NaBr, and NaI produced the Cl and Br derivatives of pretrichodermamide A and a new iodinated derivative, iododithiobrevamide, respectively. Moreover, DMSO-added seawater medium induced the production of diketopiperazine with the unprecedented trithio-bridge, chlorotrithiobrevamide. This fermentation study on the strain as well as the structures of the metabolites obtained are described in this review.


Assuntos
Organismos Aquáticos/química , Técnicas de Cultura/métodos , Inibidores Enzimáticos/isolamento & purificação , Fungos/metabolismo , Técnicas Microbiológicas/métodos , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Trichoderma/metabolismo , Diabetes Mellitus Tipo 2 , Dicetopiperazinas/metabolismo , Dipeptídeos/metabolismo , Piperazinas/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia
8.
PLoS Pathog ; 14(5): e1007054, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29742155

RESUMO

All herpesviruses have mechanisms for passing through cell junctions, which exclude neutralizing antibodies and offer a clear path to neighboring, uninfected cells. In the case of herpes simplex virus type 1 (HSV-1), direct cell-to-cell transmission takes place between epithelial cells and sensory neurons, where latency is established. The spreading mechanism is poorly understood, but mutations in four different HSV-1 genes can dysregulate it, causing neighboring cells to fuse to produce syncytia. Because the host proteins involved are largely unknown (other than the virus entry receptor), we were intrigued by an earlier discovery that cells infected with wild-type HSV-1 will form syncytia when treated with salubrinal. A biotinylated derivative of this drug was used to pull down cellular complexes, which were analyzed by mass spectrometry. One candidate was a protein tyrosine phosphatase (PTP1B), and although it ultimately proved not to be the target of salubrinal, it was found to be critical for the mechanism of cell-to-cell spread. In particular, a highly specific inhibitor of PTP1B (CAS 765317-72-4) blocked salubrinal-induced fusion, and by itself resulted in a dramatic reduction in the ability of HSV-1 to spread in the presence of neutralizing antibodies. The importance of this phosphatase was confirmed in the absence of drugs by using PTP1B-/- cells. Importantly, replication assays showed that virus titers were unaffected when PTP1B was inhibited or absent. Only cell-to-cell spread was altered. We also examined the effects of salubrinal and the PTP1B inhibitor on the four Syn mutants of HSV-1, and strikingly different responses were found. That is, both drugs individually enhanced fusion for some mutants and reduced fusion for others. PTP1B is the first host factor identified to be specifically required for cell-to-cell spread, and it may be a therapeutic target for preventing HSV-1 reactivation disease.


Assuntos
Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Animais , Linhagem Celular , Chlorocebus aethiops , Cinamatos/metabolismo , Células Gigantes/metabolismo , Células Gigantes/virologia , Herpesvirus Humano 1/fisiologia , Humanos , Junções Intercelulares/metabolismo , Espectrometria de Massas/métodos , Receptores Virais/metabolismo , Tioureia/análogos & derivados , Tioureia/metabolismo , Células Vero , Proteínas do Envelope Viral/metabolismo , Internalização do Vírus , Replicação Viral
9.
Exp Gerontol ; 104: 66-71, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29421605

RESUMO

The insulin and Brain-Derived Neurotrophic Factor (BDNF) signaling in the hippocampus promotes synaptic plasticity and memory formation. On the other hand, aging is related to the cognitive decline and is the main risk factor for Alzheimer's Disease (AD). The Protein-Tyrosine Phosphatase 1B (PTP1B) is related to several deleterious processes in neurons and emerges as a promising target for new therapies. In this context, our study aims to investigate the age-related changes in PTP1B content, insulin signaling, ß-amyloid content, and Tau phosphorylation in the hippocampus of middle-aged rats. Young (3 months) and middle-aged (17 months) Wistar rats were submitted to Morris-water maze (MWM) test, insulin tolerance test, and molecular analysis in the hippocampus. Aging resulted in increased body weight, and insulin resistance and decreases learning process in MWM. Interestingly, the middle-aged rats have higher levels of PTP-1B, lower phosphorylation of IRS-1, Akt, GSK3ß, mTOR, and TrkB. Also, the aging process increased Tau phosphorylation and ß-amyloid content in the hippocampus region. In summary, this study provides new evidence that aging-related PTP1B increasing, contributing to insulin resistance and the onset of the AD.


Assuntos
Hipocampo/fisiologia , Insulina/fisiologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Aprendizagem Espacial/fisiologia , Envelhecimento/fisiologia , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hipocampo/metabolismo , Resistência à Insulina/fisiologia , Masculino , Aprendizagem em Labirinto , Ratos , Ratos Wistar , Transdução de Sinais/fisiologia
10.
J Microbiol Biotechnol ; 27(5): 878-895, 2017 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-28238001

RESUMO

Phosphorylation, a critical mechanism in biological systems, is estimated to be indispensable for about 30% of key biological activities, such as cell cycle progression, migration, and division. It is synergistically balanced by kinases and phosphatases, and any deviation from this balance leads to disease conditions. Pathway or biological activity-based abnormalities in phosphorylation and the type of involved phosphatase influence the outcome, and cause diverse diseases ranging from diabetes, rheumatoid arthritis, and numerous cancers. Protein tyrosine phosphatases (PTPs) are of prime importance in the process of dephosphorylation and catalyze several biological functions. Abnormal PTP activities are reported to result in several human diseases. Consequently, there is an increased demand for potential PTP inhibitory small molecules. Several strategies in structure-based drug designing techniques for potential inhibitory small molecules of PTPs have been explored along with traditional drug designing methods in order to overcome the hurdles in PTP inhibitor discovery. In this review, we discuss druggable PTPs and structure-based virtual screening efforts for successful PTP inhibitor design.


Assuntos
Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacologia , Fosforilação/fisiologia , Proteínas Tirosina Fosfatases/efeitos dos fármacos , Proteínas Tirosina Fosfatases/fisiologia , Domínio Catalítico , Diabetes Mellitus/tratamento farmacológico , Doença , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Descoberta de Drogas , Inibidores Enzimáticos/química , Humanos , Modelos Moleculares , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Monoéster Fosfórico Hidrolases/fisiologia , Fosfotransferases/fisiologia , Conformação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 1/efeitos dos fármacos , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Proteínas Tirosina Fosfatases/química , Proteínas Tirosina Fosfatases/classificação
11.
Blood ; 129(11): 1480-1490, 2017 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-28082443

RESUMO

Chronic activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways is a hallmark of a variety of B-cell lymphomas, including classical Hodgkin lymphoma (cHL). Constitutive JAK/STAT signaling is crucial for survival and proliferation of Hodgkin/Reed-Sternberg (HRS) cells, the malignant cells of cHL. Although the molecular basis of this constitutive JAK/STAT signaling in cHL has not been completely understood, accumulating reports highlight the role of an inactivation or reduced expression of negative JAK/STAT regulators such as silencer of cell signaling 1 (SOCS1) or protein-tyrosine phosphatase 1B (PTP1B) in this process. Here, we report the expression of truncated PTP1B mRNA variants identified in cHL cell lines and primary cHL tumor samples lacking either 1 or several exon sequences. One of these novel PTP1B variants, a splice variant lacking exon 6 (PTP1BΔ6), was found expressed at low levels in cHL cell lines. However, serum stimulation of cHL augmented the expression of PTP1BΔ6 significantly. Functional characterization of PTP1BΔ6 revealed a positive effect on interferon-γ- and interleukin-4-induced JAK/STAT activity in HEK293 or HEK293-STAT6 cells, and on the basal STAT activity in stably transfected L-428 and U-HO1 cHL cell lines. Furthermore, PTP1BΔ6 expression increased the proliferation of L-428 and U-HO1 cells and reduced cytotoxic effects of the chemotherapeutical agents gemcitabine and etoposide distinctively. Collectively, these data indicate that PTP1BΔ6 is a positive regulator of JAK/STAT signaling in cHL.


Assuntos
Doença de Hodgkin/patologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Transdução de Sinais , Antineoplásicos/farmacologia , Morte Celular , Proliferação de Células , Células HEK293 , Doença de Hodgkin/genética , Humanos , Interferon gama/farmacologia , Interleucina-4/farmacologia , Janus Quinases/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiologia , RNA Mensageiro/genética , Fatores de Transcrição STAT/metabolismo , Regulação para Cima
12.
Hepatology ; 63(5): 1528-43, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26840794

RESUMO

UNLABELLED: The effective therapeutic targets for hepatocellular carcinoma remain limited. Pituitary homeobox 1 (PITX1) functions as a tumor suppressor in hepatocarcinogenesis by regulating the expression level of Ras guanosine triphosphatase-activating protein. Here, we report that protein tyrosine phosphatases 1B (PTP1B) directly dephosphorylated PITX1 at Y160, Y175, and Y179 to further weaken the protein stability of PITX. The PTP1B-dependent decline of PITX1 reduced its transcriptional activity for p120RasGAP (RASA1), a Ras guanosine triphosphatase-activating protein. Both silencing of PTP1B and PTP1B inhibitor up-regulated the PITX1-p120RasGAP axis through hyperphosphorylation of PITX1. Sorafenib, the first and only targeted drug approved for hepatocellular carcinoma, directly decreased PTP1B activity and promoted the expression of PITX1 and p120RasGAP by PITX1 hyperphosphorylation. Molecular docking also supported the potential interaction between PTP1B and sorafenib. PTP1B overexpression impaired the sensitivity of sorafenib in vitro and in vivo, implying that PTP1B has a significant effect on sorafenib-induced apoptosis. In sorafenib-treated tumor samples, we further found inhibition of PTP1B activity and up-regulation of the PITX1-p120RasGAP axis, suggesting that PTP1B inhibitor may be effective for the treatment of hepatocellular carcinoma. By immunohistochemical staining of hepatic tumor tissue from 155 patients, the expression of PTP1B was significantly in tumor parts higher than nontumor parts (P = 0.02). Furthermore, high expression of PTP1B was significantly associated with poor tumor differentiation (P = 0.031). CONCLUSION: PTP1B dephosphorylates PITX1 to weaken its protein stability and the transcriptional activity for p120RasGAP gene expression and acts as a determinant of the sorafenib-mediated drug effect; targeting the PITX1-p120RasGAP axis with a PTP1B inhibitor may provide a new therapy for patients with hepatocellular carcinoma.


Assuntos
Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Fatores de Transcrição Box Pareados/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Proteína p120 Ativadora de GTPase/genética , Animais , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Modelos Moleculares , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Compostos de Fenilureia/farmacologia , Fosforilação , Sorafenibe
13.
Toxicology ; 337: 10-20, 2015 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-26299811

RESUMO

Phosphorylation of tyrosine residues within proteins, which is controlled by the reciprocal action of protein tyrosine kinases and protein tyrosine phosphatases, plays a key role in regulating almost all physiological responses. Therefore, it comes as no surprise that once the balance of tyrosine phosphorylation is disturbed, drastic effects can occur. Protein tyrosine phosphatase 1B (PTP1B), a classical non-transmembrane tyrosine phosphatase, is a pivotal regulator and promising drug target in type 2 diabetes and obesity. Recently it has received renewed attention in liver diseases and represents an intriguing opportunity as a drug target by modulating hepatocyte death and survival, hepatic lipogenesis and so on. Here, the multiple roles of PTP1B in liver diseases will be presented, with respect to liver regeneration, drug-induced liver disease, non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma.


Assuntos
Hepatopatias/tratamento farmacológico , Hepatopatias/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Animais , Hepatócitos/enzimologia , Hepatócitos/patologia , Humanos , Fígado/enzimologia , Fígado/patologia , Hepatopatias/patologia , Regeneração Hepática/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/classificação , Proteína Tirosina Fosfatase não Receptora Tipo 1/efeitos dos fármacos
14.
J Mol Cell Biol ; 7(6): 517-28, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26063615

RESUMO

Dendritic cells (DC) are the major antigen-presenting cells bridging innate and adaptive immunity, a function they perform by converting quiescent DC to active, mature DC with the capacity to activate naïve T cells. They do this by migrating from the tissues to the T cell area of the secondary lymphoid tissues. Here, we demonstrate that myeloid cell-specific genetic deletion of PTP1B (LysM PTP1B) leads to defects in lipopolysaccharide-driven bone marrow-derived DC (BMDC) activation associated with increased levels of phosphorylated Stat3. We show that myeloid cell-specific PTP1B deletion also causes decreased migratory capacity of epidermal DC, as well as reduced CCR7 expression and chemotaxis to CCL19 by BMDC. PTP1B deficiency in BMDC also impairs their migration in vivo. Further, immature LysM PTP1B BMDC display fewer podosomes, increased levels of phosphorylated Src at tyrosine 527, and loss of Src localization to podosome puncta. In co-culture with T cells, LysM PTP1B BMDC establish fewer and shorter contacts than control BMDC. Finally, LysM PTP1B BMDC fail to present antigen to T cells as efficiently as control BMDC. These data provide first evidence for a key regulatory role for PTP1B in mediating a central DC function of initiating adaptive immune responses in response to innate immune cell activation.


Assuntos
Células Dendríticas/imunologia , Ativação Linfocitária , Podossomos/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Linfócitos T/imunologia , Animais , Células da Medula Óssea , Diferenciação Celular , Movimento Celular/fisiologia , Células Cultivadas , Quimiocina CCL19/metabolismo , Técnicas de Cocultura , Feminino , Camundongos , Camundongos Knockout , Células Mieloides/enzimologia , Coativador 1 de Receptor Nuclear/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , Receptores CCR7/metabolismo , Fator de Transcrição STAT3/metabolismo
15.
J Hepatol ; 63(3): 713-21, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26026874

RESUMO

BACKGROUND & AIMS: Heme oxygenase 1 (HO-1)-mediated increases in adiponectin, ameliorate the deleterious effects of obesity and metabolic syndrome; however, the effect of HO-1 on hepatic lipid metabolism remains elusive. The aim of this study is to evaluate the role of HO-1 in hepatic lipid metabolism. METHODS: Functional studies were performed using C57BL/6J (WT) mice and Sirt1 liver specific mutant (Sirt1-deficient) mice. The molecular mechanism was explored in primary hepatocytes and mouse liver. RESULTS: Chronic exposure to high-fat diet (HFD) induced hepatic steatosis in WT mice. Treatment of WT mice on HFD with cobalt protoporphyrin (CoPP), an inducer of HO-1 activity, decreased body weight and visceral fat content, reduced intracellular hepatic triglyceride and serum total cholesterol concentrations, and decreased liver lipid droplet formation. Compared with WT mice, the administration of CoPP to Sirt1-deficient mice on HFD increased visceral fat content, and slightly promoted liver lipid droplet formation. CoPP improved glucose tolerance and insulin sensitivity in WT mice on HFD, but compromised insulin sensitivity in Sirt1-deficient mice on HFD. Furthermore, CoPP-induced Sirt1 expression and decreased sterol regulatory element binding protein 1c (SREBP-1c) expression in WT mice on HFD. However, CoPP promoted SREBP-1c expression in Sirt1-deficient hepatocytes, which was reversed by a protein tyrosine phosphatase 1b inhibitor. Additionally, while the administration of CoPP to WT mice on HFD improved antioxidant and anti-inflammatory states, these CoPP-mediated effects were abolished in Sirt1-deficient mice. CONCLUSIONS: Sirt1 mediates the effect of CoPP on ameliorating liver metabolic damage caused by HFD.


Assuntos
Fígado Gorduroso/prevenção & controle , Heme Oxigenase-1/fisiologia , Fígado/efeitos dos fármacos , Protoporfirinas/farmacologia , Sirtuína 1/fisiologia , Animais , Células Cultivadas , Dieta Hiperlipídica , Resistência à Insulina , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Proteína de Ligação a Elemento Regulador de Esterol 1/fisiologia
16.
Cancer Lett ; 359(2): 218-25, 2015 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-25617799

RESUMO

Previous studies have demonstrated that protein tyrosine phosphatase 1B (PTP1B) can promote tumor progression in breast cancer, colon cancer and prostate cancer. Additionally, PTP1B acts as a tumor suppressor in other cancers, such as esophageal cancer and lymphoma. These findings suggest that PTP1B functions as a double-facet molecule in tumors, and the role of PTP1B in non-small cell lung cancer (NSCLC) is unknown. The present study demonstrates that the expression of PTP1B in NSCLC tissue is significantly higher than its expression in benign lung disease and is associated with the stage and overall survival (OS) of NSCLC patients. In vitro studies have demonstrated that PTP1B promotes the proliferation and metastasis of NSCLC cells by reducing the expression of p-src (Tyr527), which activates src and ERK1/2. This study provides the first exploration of the role of PTP1B in the proliferation and metastasis of NSCLC and subsequently elucidates the role of PTP1B in cancer. Our study uncovered that PTP1B can promote NSCLC proliferation and metastasis by activating src and subsequently ERK1/2 and provides a theoretical basis for future applications of PTP1B inhibitors in the treatment of NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/enzimologia , Proliferação de Células , Neoplasias Pulmonares/enzimologia , Sistema de Sinalização das MAP Quinases , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Quinases da Família src/metabolismo , Adenocarcinoma/enzimologia , Adenocarcinoma/mortalidade , Adenocarcinoma/secundário , Animais , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Carcinoma Pulmonar de Células não Pequenas/secundário , Carcinoma de Células Escamosas/enzimologia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/secundário , Linhagem Celular Tumoral , Ativação Enzimática , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/mortalidade , Neoplasias Pulmonares/patologia , Metástase Linfática , Masculino , Camundongos SCID , Pessoa de Meia-Idade , Transplante de Neoplasias , Modelos de Riscos Proporcionais
17.
Am J Physiol Endocrinol Metab ; 308(1): E40-50, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25352433

RESUMO

Leptin resistance is induced by the feedback inhibitors tyrosine phosphatase-1B (PTP1B) and decreased Src homology 2 domain-containing tyrosine phosphatase-2 (SHP-2) signaling. To investigate the participation of PTP1B and SHP-2 in LPS-induced leptin resistance, we injected repeated (6-LPS) intraperitoneal LPS doses (100 µg/kg ip) for comparison with a single (1-LPS) treatment and evaluated the expression of SHP-2, PTP1B, p-ERK1/2, and p-STAT3 in the hypothalamus of male Wistar rats. The single LPS treatment increased the expression of p-STAT3 and PTP1B but not SHP-2. The repeated LPS treatment reduced SHP-2, increased PTP1B, and did not change p-STAT3. We observed that the PTP1B expression induced by the endotoxin was highly colocalized with leptin receptor cells in the hypothalamus of LepRb-IRES-Cre-tdTomato reporter mice. The single, but not the repeated, LPS treatment decreased the food intake and body weight. Leptin had no stimulatory effect on the hypophagia, body weight loss, or pSTAT3 expression in 6-LPS rats, indicating leptin unresponsiveness. Notably, the PTP1B inhibitor (3.0 nmol/rat in 5 µl icv) restored the LPS-induced hypophagia in 6-LPS rats and restored the ability of leptin to reduce food intake and body weight as well as to phosphorylate STAT3 in the arcuate, paraventricular, and ventromedial nuclei of the hypothalamus. The present data suggest that an increased PTP1B expression in the hypothalamus underlies the development of leptin resistance during repeated exposure to LPS. Our findings contribute to understanding the mechanisms involved in leptin resistance during low-grade inflammation as seen in obesity.


Assuntos
Resistência a Medicamentos , Inflamação/metabolismo , Leptina/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Animais , Resistência a Medicamentos/efeitos dos fármacos , Resistência a Medicamentos/genética , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Lipopolissacarídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Obesidade/genética , Obesidade/metabolismo , Ratos , Ratos Wistar , Receptores para Leptina/genética , Receptores para Leptina/metabolismo
18.
Invest Ophthalmol Vis Sci ; 56(13): 8031-44, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26720454

RESUMO

PURPOSE: Insulin-like growth factor-I receptor (IGF-IR) signaling mediates retinal growth and survival and its failure may contribute to aggravate diabetic retinopathy (DR). Protein tyrosine phosphatase 1B (PTP1B) negatively modulates IGF-IR signaling, but its involvement in inflammation during DR remains unknown. We investigated whether PTP1B participates in the cross-talk between proinflammatory signaling pathways and IGF-IR-mediated signaling in the retina. METHODS: 661W photoreceptors or mouse retinal explants were treated with TNFα, IL6, and IL1ß. Insulin-like growth factor-I receptor signaling cascade was evaluated in the absence or presence of PTP1B. db/db mice were used to test a PTP1B inhibitor in retinal gliosis. RESULTS: 661W retinal cells and retinal explants responded to IGF-I by inducing IGF-IR tyrosine (13-fold) and Akt phosphorylations (7- and 3-fold for serine 473 and threonine 308, respectively). Cytokines triggered early activation of stress kinases (c-jun [NH2] terminal kinase [JNK] and p38 MAPK), resulting in insulin receptor substrate 1 (IRS1) serine 307 phosphorylation that precedes its degradation. Pretreatment of 661W cells or retinal explants with cytokines upregulated PTP1B protein levels (1.45- and 4.5-fold, respectively), induced IRS1 degradation and decreased IGF-I-mediated IGF-IR/Akt phosphorylation. Silencing or deficiency in PTP1B ameliorated the negative effects of cytokines on IGF-IR signaling. Cytokines increased glial fibrillary acidic protein (GFAP) expression in retinal explants by 4.5-fold, this response being reduced by 2-fold with a PTP1B inhibitor. Protein tyrosine phosphatase 1B protein levels increased by 3-fold in retinas from db/db mice and its inhibition reduced gliosis. CONCLUSIONS: Targeting PTP1B might be useful for modulating IGF-I effects in retinal cells during DR.


Assuntos
Retinopatia Diabética/fisiopatologia , Gliose/fisiopatologia , Células Fotorreceptoras de Vertebrados/fisiologia , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Receptor IGF Tipo 1/fisiologia , Transdução de Sinais/fisiologia , Análise de Variância , Animais , Células Cultivadas , Modelos Animais de Doenças , Interleucina-1beta/farmacologia , Interleucina-6/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Células Fotorreceptoras de Vertebrados/efeitos dos fármacos , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Fator de Necrose Tumoral alfa/farmacologia
19.
Mol Cell ; 55(5): 651-3, 2014 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-25192363

RESUMO

Oncogene-induced senescence (OIS) provides an important, but incompletely understood, barrier to tumorigenesis. In this issue, Yang et al. (2014) surprisingly report that inactivation of PTP1B by reactive oxygen species is essential for OIS, via effects on AGO2 and microRNA maturation.


Assuntos
Proteínas Argonautas/metabolismo , Inativação Gênica , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Tirosina/metabolismo , Proteínas ras/fisiologia , Humanos
20.
Mol Cell ; 55(5): 782-90, 2014 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-25175024

RESUMO

Oncogenic RAS (H-RAS(V12)) induces premature senescence in primary cells by triggering production of reactive oxygen species (ROS), but the molecular role of ROS in senescence remains elusive. We investigated whether inhibition of protein tyrosine phosphatases by ROS contributed to H-RAS(V12)-induced senescence. We identified protein tyrosine phosphatase 1B (PTP1B) as a major target of H-RAS(V12)-induced ROS. Inactivation of PTP1B was necessary and sufficient to induce premature senescence in H-RAS(V12)-expressing IMR90 fibroblasts. We identified phospho-Tyr 393 of argonaute 2 (AGO2) as a direct substrate of PTP1B. Phosphorylation of AGO2 at Tyr 393 inhibited loading with microRNAs (miRNAs) and thus miRNA-mediated gene silencing, which counteracted the function of H-RAS(V12)-induced oncogenic miRNAs. Overall, our data illustrate that premature senescence in H-RAS(V12)-transformed primary cells is a consequence of oxidative inactivation of PTP1B and inhibition of miRNA-mediated gene silencing.


Assuntos
Proteínas Argonautas/metabolismo , Inativação Gênica , Proteína Tirosina Fosfatase não Receptora Tipo 1/fisiologia , Tirosina/metabolismo , Proteínas ras/fisiologia , Proteínas Argonautas/química , Linhagem Celular , Senescência Celular/genética , Humanos , MicroRNAs/metabolismo , Fosforilação , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Tirosina/química , Proteínas ras/genética , Proteínas ras/metabolismo
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