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1.
Antioxidants (Basel) ; 10(9)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34573040

RESUMO

The optimization of conditions to promote the stemness of pluripotent cells in vitro is instrumental for their use in advanced therapies. We show here that exposure of human iPSCs and human ESCs to low concentrations of the chemical NO donor DETA/NO leads to stabilization of hypoxia-inducible factors (HIF-1α and HIF-2α) under normoxia, with this effect being dependent on diminished Pro 402 hydroxylation and decreased degradation by the proteasome. Moreover, the master genes of pluripotency, NANOG and OCT-4, were upregulated. NO also induces a shift in the metabolic profile of PSCs, with an increased expression of hypoxia response genes in glycolysis. Furthermore, a reduction in the mitochondrial membrane potential with lower oxygen consumption and increased expression of mitochondrial fusion regulators, such as DRP1, was observed. The results reported here indicate that NO mimics hypoxia response in human PSCs and enhances their stemness properties when cultured under normoxic conditions.

2.
Parasitol Int ; 85: 102428, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34329752

RESUMO

Fascioliasis is a zoonotic disease caused by parasites of the genus Fasciola spp. which cause an important loss to the livestock industry. The objectives of this study were: to estimate the prevalence of fascioliasis in three provinces of Amazonas, to evaluate possible risk factors of infection in cattle and to genetically characterize the Fasciola haplotypes circulating in this area. According to the results the prevalence of fascioliasis in cattle was 90.13% (712/790). Odds ratio results showed a significant association between fascioliasis and the Brown Swiss breed (OR = 2.62; 95% CI: 1.57-4.35; p < 0.001), and with female cattle older than 30 months (OR = 1.71; 95% CI: 1.05-2.79; p < 0.031). According to the molecular genetic studies using the gene marker NAD1, six haplotypes of Fasciola hepatica were found in the 35 infected livers collected. The results obtained in this study are concerning due to the high prevalence presented and it reveals the necessity of a continuing monitoring because of the high risk of transmission to humans.


Assuntos
Doenças dos Bovinos/epidemiologia , Fasciolíase/veterinária , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Fasciolíase/epidemiologia , Fasciolíase/parasitologia , Feminino , Masculino , Peru/epidemiologia , Prevalência , Fatores de Risco
3.
Am J Trop Med Hyg ; 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782210

RESUMO

In November 2018, we diagnosed a cluster of falciparum malaria cases in three Chilean travelers returning from Nigeria. Two patients were treated with sequential intravenous artesunate plus oral atovaquone/proguanil (AP) and one with oral AP. The third patient, a 23-year-old man, presented with fever on day 29 after oral AP treatment and was diagnosed with recrudescent falciparum malaria. The patient was then treated with oral mefloquine, followed by clinical recovery and resolution of parasitemia. Analysis of day 0 and follow-up blood samples, collected on days 9, 29, 34, 64, and 83, revealed that parasitemia had initially decreased but then increased on day 29. Sequencing confirmed Tyr268Cys mutation in the cytochrome b gene, associated with atovaquone resistance, in isolates collected on days 29 and 34 and P. falciparum dihydrofolate reductase mutation Asn51Ile, associated with proguanil resistance in all successfully sequenced samples. Molecular characterization of imported malaria contributes to clinical management in non-endemic countries, helps ascertain the appropriateness of antimalarial treatment policies, and contributes to the reporting of drug resistance patterns from endemic regions.

4.
Malar J ; 20(1): 88, 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33579285

RESUMO

BACKGROUND: Malaria remains a serious health threat in the Amazonas Region of Peru and approximately 95% of the cases, mainly Plasmodium vivax, are found in native communities of The Rio Santiago District, Condorcanqui Province. In 2019, more than one thousand malaria cases were reported, with an unusual number of Plasmodium falciparum autochthonous cases. The present study aims to report this P. falciparum outbreak while describing the epidemiology of malaria and the risk factors associated in the native communities of Amazonas, Peru. METHODS: The DIRESA-Amazonas in collaboration with the Condorcanqui Health Network and the Institute of Tropical Diseases of the UNTRM carried out a malaria Active Case Detection (ACD III) between January 31st and February 10th of 2020. A total of 2718 (47.4%) individuals from 21 native communities grouped in eight sanitary districts, were screened for malaria infections. Each participant was screened for malaria using microscopy. Follow-up surveys were conducted for all malaria positive individuals to collect socio-demographic data. Spatial clustering of infection risk was calculated using a generalized linear model (GLM). Analysis of risk considered factors such as gender, age, type of infection, symptomatology, and parasitaemia. RESULTS: The study suggests that the P. falciparum index case was imported from Loreto and later spread to other communities of Rio Santiago during 2019. The ACD III reported 220 (8.1%) malaria cases, 46 P. falciparum, 168 P. vivax and 6 mixed infections. SaTScan analysis detected a cluster of high infection risk in Middle Rio Santiago and a particular high P. falciparum infection risk cluster in Upper Rio Santiago. Interestingly, the evaluation of different risk factors showed significant associations between low parasitaemia and P. falciparum asymptomatic cases. CONCLUSION: This is the first report of a P. falciparum outbreak in native communities of Condorcanqui, Amazonas. Timely identification and treatment of symptomatic and asymptomatic cases are critical to achieve malaria control and possible elimination in this area. However, the current malaria situation in Condorcanqui is uncertain, given that malaria ACD activities have been postponed due to COVID-19.


Assuntos
Surtos de Doenças , Malária Falciparum/epidemiologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peru/epidemiologia , População Rural , Adulto Jovem
6.
ACS Omega ; 5(32): 20270-20282, 2020 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-32832780

RESUMO

Pluripotent stem cells maintain the property of self-renewal and differentiate into all cell types under clear environments. Though the gene regulatory mechanism for pluripotency has been investigated in recent years, it is still not completely understood. Here, we show several signaling pathways involved in the maintenance of pluripotency. To investigate whether AMPK is involved in maintaining the pluripotency in mouse embryonic stem cells (mESCs) and elucidating the possible molecular mechanisms, implicated D3 and R1/E mESC lines were used in this study. Cells were cultured in the absence or presence of LIF and treated with 1 mM and 0.5 mM 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR), 2 mM metformin, compound C, and the PI3K inhibitor LY294002 for 24, 72, and 120 h. The levels of Nanog, Oct3/4, and REX1 and Brachyury, Notch2, and Gata4 mRNAs and Nanog or OCT3/4 protein levels were analyzed. Alkaline phosphatase and the cellular cycle were determined. The pGSK3ß, GSK3ß, p-ß-catenin, and ß-catenin protein levels were also investigated. We found that AMPK activators such as AICAR and metformin increase mRNA expression of pluripotency markers and decrease mRNA expression of differentiation markers in R1/E and D3 ES cells. AICAR increases phosphatase activity and arrests the cellular cycle in the G1 phase in these cells. We describe that AICAR effects were mediated by AMPK activation using a chemical inhibitor or by silencing this gene. AICAR effects were also mediated by PI3K, GSK3ß, and ß-catenin in R1/E ES cells. According to our findings, we provide a mechanism by which AICAR increases and maintains a pluripotency state through enhanced Nanog expression, involving AMPK/PI3K and p-GSK3ß Ser21/9 pathways backing up the AICAR function as a potential target for this drug controlling pluripotency. The highlights of this study are that AICAR (5-aminoimidazole-4-carboxamied-1-b-riboside), an AMP protein kinase (AMPK) activator, blocks the ESC differentiation and AMPK is a key enzyme for pluripotency and shows valuable data to clarify the molecular pluripotency mechanism.

7.
Front Immunol ; 11: 609961, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33633730

RESUMO

Snakebite envenoming is a global neglected disease with an incidence of up to 2.7 million new cases every year. Although antivenoms are so-far the most effective treatment to reverse the acute systemic effects induced by snakebite envenoming, they have a limited therapeutic potential, being unable to completely neutralize the local venom effects. Local damage, such as dermonecrosis and myonecrosis, can lead to permanent sequelae with physical, social, and psychological implications. The strong inflammatory process induced by snake venoms is associated with poor tissue regeneration, in particular the lack of or reduced skeletal muscle regeneration. Mesenchymal stromal cells (MSCs)-based therapies have shown both anti-inflammatory and pro-regenerative properties. We postulate that using allogeneic MSCs or their cell-free products can induce skeletal muscle regeneration in snakebite victims, improving all the three steps of the skeletal muscle regeneration process, mainly by anti-inflammatory activity, paracrine effects, neovascularization induction, and inhibition of tissue damage, instrumental for microenvironment remodeling and regeneration. Since snakebite envenoming occurs mainly in areas with poor healthcare, we enlist the principles and potential of MSCs-based therapies and discuss regulatory issues, good manufacturing practices, transportation, storage, and related-procedures that could allow the administration of these therapies, looking forward to a safe and cost-effective treatment for a so far unsolved and neglected health problem.


Assuntos
Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/metabolismo , Desenvolvimento Muscular , Músculo Esquelético/fisiopatologia , Regeneração , Mordeduras de Serpentes/cirurgia , Animais , Humanos , Mediadores da Inflamação/metabolismo , Transplante de Células-Tronco Mesenquimais/efeitos adversos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Necrose , Fenótipo , Transdução de Sinais , Mordeduras de Serpentes/diagnóstico , Mordeduras de Serpentes/metabolismo , Mordeduras de Serpentes/fisiopatologia , Resultado do Tratamento
8.
Front Immunol ; 10: 1151, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31231366

RESUMO

Cell therapy is a progressively growing field that is rapidly moving from preclinical model development to clinical application. Outcomes obtained from clinical trials reveal the therapeutic potential of stem cell-based therapy to deal with unmet medical treatment needs for several disorders with no therapeutic options. Among adult stem cells, mesenchymal stem cells (MSCs) are the leading cell type used in advanced therapies for the treatment of autoimmune, inflammatory and vascular diseases. To date, the safety and feasibility of autologous MSC-based therapy has been established; however, their indiscriminate use has resulted in mixed outcomes in preclinical and clinical studies. While MSCs derived from diverse tissues share common properties depending on the type of clinical application, they markedly differ within clinical trials in terms of efficacy, resulting in many unanswered questions regarding the application of MSCs. Additionally, our experience in clinical trials related to critical limb ischemia pathology (CLI) shows that the therapeutic efficacy of these cells in different animal models has only been partially reproduced in humans through clinical trials. Therefore, it is crucial to develop new research to identify pitfalls, to optimize procedures and to clarify the repair mechanisms used by these cells, as well as to be able to offer a next generation of stem cell that can be routinely used in a cost-effective and safe manner in stem cell-based therapies targeting CLI.

9.
PLoS One ; 12(11): e0187547, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29099856

RESUMO

ß-cells release hexameric Zn2+-insulin into the extracellular space, but monomeric Zn2+-free insulin appears to be the only biologically active form. The mechanisms implicated in dissociation of the hexamer remain unclear, but they seem to be Zn2+ concentration-dependent. In this study, we investigate the influence of albumin binding to Zn2+ on Zn2+-insulin dissociation into Zn2+-free insulin and its physiological, methodological and therapeutic relevance. Glucose and K+-induced insulin release were analyzed in isolated mouse islets by static incubation and perifusion experiments in the presence and absence of albumin and Zn2+ chelators. Insulin tolerance tests were performed in rats using different insulin solutions with and without Zn2+ and/or albumin. Albumin-free buffer does not alter quantification by RIA of Zn2+-free insulin but strongly affects RIA measurements of Zn2+-insulin. In contrast, accurate determination of Zn2+-insulin was obtained only when bovine serum albumin or Zn2+ chelators were present in the assay buffer solution. Albumin and Zn2+ chelators do not modify insulin release but do affect insulin determination. Preincubation with albumin or Zn2+ chelators promotes the conversion of "slow" Zn2+-insulin into "fast" insulin. Consequently, insulin diffusion from large islets is ameliorated in the presence of Zn2+ chelators. These observations support the notion that the Zn2+-binding properties of albumin improve the dissociation of Zn2+-insulin into subunits after exocytosis, which may be useful in insulin determination, insulin pharmacokinetic assays and islet transplantation.


Assuntos
Quelantes/química , Exocitose , Insulina/metabolismo , Albumina Sérica/metabolismo , Zinco/química , Animais , Glicemia/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Camundongos , Radioimunoensaio , Ratos , Ratos Wistar , Albumina Sérica/química , Zinco/metabolismo
10.
World J Stem Cells ; 9(2): 26-36, 2017 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-28289506

RESUMO

Mitochondrial dysfunction and endoplasmic reticulum stress (ERS) are global processes that are interrelated and regulated by several stress factors. Nitric oxide (NO) is a multifunctional biomolecule with many varieties of physiological and pathological functions, such as the regulation of cytochrome c inhibition and activation of the immune response, ERS and DNA damage; these actions are dose-dependent. It has been reported that in embryonic stem cells, NO has a dual role, controlling differentiation, survival and pluripotency, but the molecular mechanisms by which it modulates these functions are not yet known. Low levels of NO maintain pluripotency and induce mitochondrial biogenesis. It is well established that NO disrupts the mitochondrial respiratory chain and causes changes in mitochondrial Ca2+ flux that induce ERS. Thus, at high concentrations, NO becomes a potential differentiation agent due to the relationship between ERS and the unfolded protein response in many differentiated cell lines. Nevertheless, many studies have demonstrated the need for physiological levels of NO for a proper ERS response. In this review, we stress the importance of the relationships between NO levels, ERS and mitochondrial dysfunction that control stem cell fate as a new approach to possible cell therapy strategies.

11.
J Cell Biochem ; 117(9): 2078-88, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26853909

RESUMO

Nitric oxide (NO) delays mouse embryonic stem cell (mESC) differentiation by regulating genes linked to pluripotency and differentiation. Nevertheless, no profound study has been conducted on cell differentiation regulation by this molecule through signaling on essential biological functions. We sought to demonstrate that NO positively regulates the pluripotency transcriptional core, enforcing changes in the chromatin structure, in addition to regulating cell proliferation, and signaling pathways with key roles in stemness. Culturing mESCs with 2 µM of the NO donor diethylenetriamine/NO (DETA/NO) in the absence of leukemia inhibitory factor (LIF) induced significant changes in the expression of 16 genes of the pluripotency transcriptional core. Furthermore, treatment with DETA/NO resulted in a high occupancy of activating H3K4me3 at the Oct4 and Nanog promoters and repressive H3K9me3 and H3k27me3 at the Brachyury promoter. Additionally, the activation of signaling pathways involved in pluripotency, such as Gsk3-ß/ß-catenin, was observed, in addition to activation of PI3 K/Akt, which is consistent with the protection of mESCs from cell death. Finally, a decrease in cell proliferation coincides with cell cycle arrest in G2/M. Our results provide novel insights into NO-mediated gene regulation and cell proliferation and suggest that NO is necessary but not sufficient for the maintenance of pluripotency and the prevention of cell differentiation. J. Cell. Biochem. 117: 2078-2088, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Diferenciação Celular/fisiologia , Pontos de Checagem da Fase G2 do Ciclo Celular/fisiologia , Expressão Gênica/fisiologia , Pontos de Checagem da Fase M do Ciclo Celular/fisiologia , Células-Tronco Embrionárias Murinas/metabolismo , Óxido Nítrico/metabolismo , Transdução de Sinais/fisiologia , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Pontos de Checagem da Fase M do Ciclo Celular/efeitos dos fármacos , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Triazenos/farmacologia
12.
Expert Opin Biol Ther ; 15(10): 1469-89, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26156425

RESUMO

INTRODUCTION: Tremendous progress has been made in generating insulin-producing cells from pluripotent stem cells. The best outcome of the refined protocols became apparent in the first clinical trial announced by ViaCyte, based on the implantation of pancreatic progenitors that would further mature into functional insulin-producing cells inside the patient's body. AREAS COVERED: Several groups, including ours, have contributed to improve strategies to generate insulin-producing cells. Of note, the latest results have gained a substantial amount of interest as a method to create a potentially functional and limitless supply of ß-cell to revert diabetes mellitus. This review analyzes the accomplishments that have taken place over the last few decades, summarizes the state-of-art methods for ß-cell replacement therapies based on the differentiation of embryonic stem cells into glucose-responsive and insulin-producing cells in a dish and discusses alternative approaches to obtain new sources of insulin-producing cells. EXPERT OPINION: Undoubtedly, recent events preface the beginning of a new era in diabetes therapy. However, in our opinion, a number of significant hurdles still stand in the way of clinical application. We believe that the combination of the private and public sectors will accelerate the process of obtaining the desired safe and functional ß-cell surrogates.


Assuntos
Insulina/metabolismo , Células-Tronco Adultas/citologia , Biomarcadores/metabolismo , Diferenciação Celular , Diabetes Mellitus/terapia , Células-Tronco Embrionárias/citologia , Epigênese Genética , Humanos , Secreção de Insulina , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/transplante , MicroRNAs/metabolismo
14.
World J Stem Cells ; 7(3): 605-17, 2015 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-25914767

RESUMO

Stem cell pluripotency and differentiation are global processes regulated by several pathways that have been studied intensively over recent years. Nitric oxide (NO) is an important molecule that affects gene expression at the level of transcription and translation and regulates cell survival and proliferation in diverse cell types. In embryonic stem cells NO has a dual role, controlling differentiation and survival, but the molecular mechanisms by which it modulates these functions are not completely defined. NO is a physiological regulator of cell respiration through the inhibition of cytochrome c oxidase. Many researchers have been examining the role that NO plays in other aspects of metabolism such as the cellular bioenergetics state, the hypoxia response and the relationship of these areas to stem cell stemness.

15.
Stem Cells Int ; 2014: 379678, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25544848

RESUMO

The function of pluripotency genes in differentiation is a matter of investigation. We report here that Nanog and Oct4 are reexpressed in two mouse embryonic stem cell (mESC) lines following exposure to the differentiating agent DETA/NO. Both cell lines express a battery of both endoderm and mesoderm markers following induction of differentiation with DETA/NO-based protocols. Confocal analysis of cells undergoing directed differentiation shows that the majority of cells expressing Nanog express also endoderm genes such as Gata4 and FoxA2 (75.4% and 96.2%, resp.). Simultaneously, mRNA of mesodermal markers Flk1 and Mef2c are also regulated by the treatment. Acetylated histone H3 occupancy at the promoter of Nanog is involved in the process of reexpression. Furthermore, Nanog binding to the promoter of Brachyury leads to repression of this gene, thus disrupting mesendoderm transition.

16.
Islets ; 6(5-6): e995997, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25658244

RESUMO

Homeostatic levels of nitric oxide (NO) protect efficiently against apoptotic death in both human and rodent pancreatic ß cells, but the protein profile of this action remains to be determined. We have applied a 2 dimensional LC-MS-MALDI-TOF/TOF-based analysis to study the impact of protective NO in rat insulin-producing RINm5F cell line and in mouse and human pancreatic islets (HPI) exposed to serum deprivation condition. 24 proteins in RINm5F and 22 in HPI were identified to undergo changes in at least one experimental condition. These include stress response mitochondrial proteins (UQCRC2, VDAC1, ATP5C1, ATP5A1) in RINm5F cells and stress response endoplasmic reticulum proteins (HSPA5, PDIA6, VCP, GANAB) in HPI. In addition, metabolic and structural proteins, oxidoreductases and chaperones related with protein metabolism are also regulated by NO treatment. Network analysis of differentially expressed proteins shows their interaction in glucocorticoid receptor and NRF2-mediated oxidative stress response pathways and eNOS signaling. The results indicate that exposure to exogenous NO counteracts the impact of serum deprivation on pancreatic ß cell proteome. Species differences in the proteins involved are apparent.


Assuntos
Ilhotas Pancreáticas/efeitos dos fármacos , Óxido Nítrico/farmacologia , Adenosina Trifosfatases/análise , Animais , Proteínas de Ciclo Celular/análise , Linhagem Celular , Complexo III da Cadeia de Transporte de Elétrons/análise , Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico/análise , Humanos , Células Secretoras de Insulina/química , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Ilhotas Pancreáticas/química , Ilhotas Pancreáticas/citologia , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Isomerases de Dissulfetos de Proteínas/análise , Proteômica , Ratos , Proteína com Valosina , Canal de Ânion 1 Dependente de Voltagem/análise
17.
Islets ; 4(2): 108-18, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22614339

RESUMO

The reduction of pancreatic ß-cell mass is an important factor in the development of type 1 and type 2 diabetes. Understanding the mechanisms that regulate the maintenance of pancreatic ß-cell mass as well as ß-cell death is necessary for the establishment of therapeutic strategies. In this context, nitric oxide (NO) is a diatomic, gaseous, highly reactive molecule with biological activity that participates in the regulation of pancreatic ß-cell mass. Two types of cellular responses can be distinguished depending on the level of NO production. First, pancreatic ß-cells exposed to inflammatory cytokines, lipid stress or hyperglycaemia produce high concentrations of NO, mainly due to the activation of inducible NO synthase (iNOS), thus promoting cell death. Meanwhile, under homeostatic conditions, low concentrations of NO, constitutively produced by endothelial NO synthase (eNOS), promote cell survival. Here, we will discuss the current knowledge of the NO-dependent mechanisms activated during cellular responses, emphasizing those related to the regulation of cell survival.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Células Secretoras de Insulina/metabolismo , Óxido Nítrico/metabolismo , Animais , Sobrevivência Celular/fisiologia , Diabetes Mellitus Tipo 2/enzimologia , Diabetes Mellitus Tipo 2/patologia , Humanos , Células Secretoras de Insulina/enzimologia , Células Secretoras de Insulina/patologia , Óxido Nítrico Sintase Tipo II/metabolismo
18.
Hybridoma (Larchmt) ; 30(1): 53-9, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21466286

RESUMO

hnRNP K protein is a member of the heterogeneous nuclear protein (hnRNP) complex that, besides its function as a translational regulator of human mRNA, is also considered to be a transcription factor involved in tumorigenesis. PSF is a protein part of the human spliceosome and essential in RNA splicing. Here we report the generation of one monoclonal antibody GG6H9.1C3 that recognized both hnRNP K and PSF proteins using Western blot analysis, flow cytometry, and immunocytochemistry.


Assuntos
Anticorpos Monoclonais/imunologia , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/imunologia , Proteínas de Ligação a RNA/imunologia , Western Blotting , Núcleo Celular/metabolismo , Citometria de Fluxo , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/metabolismo , Humanos , Imuno-Histoquímica , Fator de Processamento Associado a PTB , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
19.
Adv Exp Med Biol ; 654: 59-75, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20217494

RESUMO

Over the last years, there has been great success in driving stem cells toward insulin-expressing cells. However, the protocols developed to date have some limitations, such as low reliability and low insulin production. The most successful protocols used for generation of insulin-producing cells from stem cells mimic in vitro pancreatic organogenesis by directing the stem cells through stages that resemble several pancreatic developmental stages. Islet cell fate is coordinated by a complex network of inductive signals and regulatory transcription factors that, in a combinatorial way, determine pancreatic organ specification, differentiation, growth, and lineage. Together, these signals and factors direct the progression from multipotent progenitor cells to mature pancreatic cells. Later in development and adult life, several of these factors also contribute to maintain the differentiated phenotype of islet cells. A detailed understanding of the processes that operate in the pancreas during embryogenesis will help us to develop a suitable source of cells for diabetes therapy. In this chapter, we will discuss the main transcription factors involved in pancreas specification and beta-cell formation.


Assuntos
Biologia do Desenvolvimento/métodos , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/patologia , Pâncreas/patologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linhagem da Célula , Sistema Endócrino/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/citologia , Camundongos , Modelos Biológicos , Proteínas do Tecido Nervoso/metabolismo , Pâncreas/embriologia , Células-Tronco/citologia , Fatores de Transcrição/metabolismo
20.
Cell Signal ; 20(2): 301-10, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18023142

RESUMO

Generation of low levels of nitric oxide (NO) contributes to beta cell survival in vitro. The purpose of this study was to explore the link between NO and the survival pathway triggered by insulin-like growth factor-1 (IGF-1) and insulin in insulin producing RINm5F cells and in pancreatic islets. Results show that exposure of cells to IGF-1/insulin protects against serum deprivation-induced apoptosis. This action is prevented with inhibitors of NO generation, PI3K and Akt. Moreover, transfection with the negative dominant form of the tyrosine kinase c-Src abrogates the effect of IGF-1 and insulin on DNA fragmentation. An increase in the expression level of NOS3 protein and in the enzyme activity is observed following exposure of serum-deprived RINm5F cells to IGF-1 and insulin. Phosphorylation of IRS-1, IRS-2 and to less extent IRS-3 takes place when serum-deprived RINm5F cells and rat pancreatic islets are exposed to either IGF-1, insulin, or diethylenetriamine nitric oxide adduct (DETA/NO). In human islets, IRS-1 and IRS-2 proteins are present and tyrosine phosphorylated upon exposure to IGF-1, insulin and DETA/NO. Both rat and human pancreatic islets undergo DNA fragmentation when cultured in serum-free medium and IGF-1, insulin and DETA/NO protect efficiently from this damage. We then conclude that generation of NO participates in the activation of survival pathways by IGF-1 and insulin in beta cells.


Assuntos
Fator de Crescimento Insulin-Like I/farmacologia , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Insulina/farmacologia , Óxido Nítrico/farmacologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adulto , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , DEET/farmacologia , Ativação Enzimática/efeitos dos fármacos , Humanos , Proteínas Substratos do Receptor de Insulina , Células Secretoras de Insulina/enzimologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Fosfoproteínas/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas pp60(c-src)/metabolismo , Ratos , Ratos Wistar , Soro
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