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1.
J Pers Assess ; 104(5): 573-585, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34569872

RESUMO

During the last decade, intellectual humility has gone from a topic of philosophical inquiry to one of serious scientific investigation. It has been variously described as a remedy for political polarization, a tool for advancing scientific credibility, and a disposition that promotes learning. However, less attention has been paid to how intellectual humility has been defined and measured or how well psychologists' definitions and measures align with one another or with philosophers' accounts. Through a systematic review of empirical intellectual humility research, we identified 18 separate definitions and 20 measures including16 unique questionnaires. We then synthesized this research to advance a new framework of intellectual humility. Implications of this framework for measurement and future research on intellectual humility are discussed.


Assuntos
Personalidade , Humanos , Inquéritos e Questionários
2.
J Pers ; 89(1): 145-165, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32897574

RESUMO

OBJECTIVE: Post-traumatic growth typically refers to enduring positive psychological change experienced as a result of adversity, trauma, or highly challenging life circumstances. Critics have challenged insights from much of the prior research on this topic, pinpointing its significant methodological limitations. In response to these critiques, we propose that post-traumatic growth can be more accurately captured in terms of personality change-an approach that affords a more rigorous examination of the phenomenon. METHOD: We outline a set of conceptual and methodological questions and considerations for future work on the topic of post-traumatic growth. RESULTS: We provide a series of recommendations for researchers from across the disciplines of clinical/counseling, developmental, health, personality, and social psychology and beyond, who are interested in improving the quality of research examining resilience and growth in the context of adversity. CONCLUSION: We are hopeful that these recommendations will pave the way for a more accurate understanding of the ubiquity, durability, and causal processes underlying post-traumatic growth.


Assuntos
Crescimento Psicológico Pós-Traumático , Transtornos de Estresse Pós-Traumáticos , Humanos , Personalidade , Transtornos da Personalidade
3.
Mucosal Immunol ; 10(2): 332-340, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27271317

RESUMO

Reactive oxygen species (ROS) produced by the phagocyte NADPH oxidase (NOX2) are required for microbial clearance; however, when produced in excess they exacerbate inflammatory response and injure surrounding tissues. NOX2 is a multicomponent enzyme composed of membrane-associated cytochrome b588 and cytosolic components p47phox, p67phox, p40phox, and rac1/2. We investigated whether vasoactive intestinal peptide (VIP), an endogenous immune-modulatory peptide, could affect ROS production by NOX2 in primary human phagocytes. VIP did not modulate basal ROS production by phagocytes, but it inhibited monocyte and not neutrophil ROS production in response to the bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (fMLF). The action of VIP was essentially mediated by high-affinity G-protein coupled receptors VPAC1 as its specific agonist, [ALA11,22,28]VIP, mimicked VIP-inhibitory effect, whereas the specific VPAC1 antagonist, PG97-269, blunted VIP action. Further, we showed that VIP inhibited fMLF-induced phosphorylation of ERK1/2 (extracellular signal-regulated kinase 1/2), p38MAPK (p38 mitogen-activated protein kinase) pathways, and phosphorylation of p47phox on Ser345 residue. Also, VIP exerted an anti-inflammatory effect in a model of carrageenan-induced inflammation in rats. We thus found that VIP exerts anti-inflammatory effects by inhibiting the "MAPK-p47phox phosphorylation-NOX2 activation" axis. These data suggest that VIP acts as a natural anti-inflammatory agent of the mucosal system and its analogs could be novel anti-inflammatory molecules.


Assuntos
Anti-Inflamatórios/uso terapêutico , Edema/terapia , Inflamação/terapia , Monócitos/imunologia , NADPH Oxidases/metabolismo , Neutrófilos/imunologia , Peptídeo Intestinal Vasoativo/uso terapêutico , Animais , Carragenina , Células Cultivadas , Edema/induzido quimicamente , Edema/imunologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Inflamação/induzido quimicamente , Inflamação/imunologia , Masculino , Glicoproteínas de Membrana/metabolismo , N-Formilmetionina Leucil-Fenilalanina/imunologia , NADPH Oxidase 2 , Fosforilação , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
4.
J Affect Disord ; 204: 197-204, 2016 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27367308

RESUMO

BACKGROUND: Beliefs about mental illness affect how individuals cope with their symptoms. Positive beliefs about mental illness (PBMI) refer to perceptions of positive attributes individuals may identify in their illness, such as beneficial consequences, enhanced creativity or cognition, or growth through adversity. METHODS: The present study developed and tested a brief measure of PBMI in 332 adults presenting for partial hospitalization with a variety of acute psychiatric conditions. RESULTS: Results indicated that older individuals and women had lower levels of PBMI than others, while individuals with bipolar disorder had higher levels of PBMI than others. PBMI significantly increased over the course of brief standard treatment. Baseline levels of PBMI, as well as changes in PBMI over the course of treatment, were associated with clinical outcomes including, but not limited to, depression and well-being. A diagnosis of bipolar disorder moderated the relationship between PBMI and only one clinical outcome, emotional lability. Increases in PBMI during treatment were associated with reduced emotional lability only in participants without bipolar disorder. LIMITATIONS: Our findings are limited by the naturalistic study design. In addition, the lack of ethnoracial diversity in our sample limits the generalization of results. CONCLUSIONS: Our results suggest that PBMI are a distinct set of beliefs that meaningfully relate to demographic characteristics, diagnostic characteristics, and clinical outcomes. Future research should examine the mechanisms through which PBMI and outcomes are related, as well as determine whether interventions designed to address PBMI (and perhaps tailored for different diagnostic groups) have clinical utility.


Assuntos
Afeto , Transtorno Bipolar/psicologia , Cultura , Autoimagem , Estigma Social , Adaptação Psicológica , Adolescente , Adulto , Fatores Etários , Idoso , Transtorno Bipolar/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Fatores Sexuais , Resultado do Tratamento , Adulto Jovem
5.
Psychol Trauma ; 7(4): 333-9, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26147518

RESUMO

The aim of the current study was to investigate the extent to which individual differences in personal growth initiative (PGI) were associated with lower reports of functional impairment of daily activities among a genocide-affected population in Rwanda. PGI measures an individual's motivation to develop as a person and the extent to which he or she is active in setting goals that work toward achieving self-improvement. We found that PGI was negatively associated with functional impairment when controlling for depression, posttraumatic stress disorder, and other demographic factors. Our results suggest that PGI may constitute an important mindset for facilitating adaptive functioning in the aftermath of adversity and in the midst of psychological distress, and as such they might have practical applications for the development of intervention programs.


Assuntos
Genocídio/psicologia , Motivação , Resiliência Psicológica , Autoimagem , Adolescente , Adulto , Idoso , Depressão , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Ruanda , Transtornos de Estresse Pós-Traumáticos/psicologia , Sobreviventes/psicologia , Adulto Jovem
6.
Behav Brain Sci ; 38: e105, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26786254

RESUMO

PASTOR represents an innovative development in the study of resilience. This commentary highlights how PASTOR can help both clarify critical questions in and benefit from engaging with new research in personality science on behavioral flexibility across situations in addition to stability over time, and also clarify the relationship between resilience and posttraumatic growth.


Assuntos
Personalidade , Resiliência Psicológica , Humanos , Transtornos da Personalidade
7.
8.
Soc Psychiatry Psychiatr Epidemiol ; 49(3): 459-65, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24173407

RESUMO

BACKGROUND: Past research suggests that culture shapes the way psychopathology is experienced and expressed. Standard psychiatric assessment instruments may therefore not capture the same underlying constructs in different contexts. The present study investigated the factor structure of a standard depression scale in a sample of Rwandan genocide survivors. METHODS: One hundred ninety six Rwandan adults provided socio-demographic information and completed the Center for Epidemiological Studies-Depression scale (CES-D), one of the most widely used self-report instruments assessing depressive symptoms, as part of a larger study on well-being and mental health in Rwanda. RESULTS: A two-factor solution provided the best fit for these CES-D data. The first factor corresponded to general depressive symptoms (including depressed affect, somatic symptoms, and interpersonal concerns) and explained 37.20% of the variance. The second factor included items assessing positive affect and explained 8.68% of the variance. CONCLUSIONS: The two-factor solution found in the present study deviates from the commonly reported four-factor structure, but is consistent with studies showing that depressed affect and somatic symptoms may not be experienced as distinct in certain non-Western and minority cultural groups.


Assuntos
Depressão/epidemiologia , Depressão/psicologia , Genocídio/psicologia , Escalas de Graduação Psiquiátrica , Sobreviventes/psicologia , Adolescente , Adulto , Idoso , Depressão/diagnóstico , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Grupos Minoritários/psicologia , Ruanda/epidemiologia , Adulto Jovem
9.
Clin Psychol (New York) ; 18(4): 275-299, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22509072

RESUMO

Despite decades of research on the etiology and treatment of depression, a significant proportion of the population is affected by the disorder, fails to respond to treatment and is plagued by relapse. Six prominent scientists, Aaron Beck, Richard Davidson, Fritz Henn, Steven Maier, Helen Mayberg, and Martin Seligman, gathered to discuss the current state of scientific knowledge on depression, and in particular on the basic neurobiological and psychopathological processes at play in the disorder. These general themes were addressed: 1) the relevance of learned helplessness as a basic process involved in the development of depression; 2) the limitations of our current taxonomy of psychological disorders; 3) the need to work towards a psychobiological process-based taxonomy; and 4) the clinical implications of implementing such a process-based taxonomy.

10.
Recept Channels ; 8(3-4): 137-53, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12529932

RESUMO

VIP and PACAP are two prominent neuropeptides that share two common G protein-coupled receptors, VPAC1 and VPAC2, while PACAP has an additional specific receptor, PAC1. This article reviews the present knowledge regarding various aspects of VPAC receptors including: 1) receptor specificity toward natural VIP-related peptides and pharmacology of synthetic agonists or antagonists; 2) genomic organization and chromosomal localization; 3) signaling and established or putative interactions with G proteins or accessory proteins such as RAMPs or PDZ-containing proteins; 4) molecular basis of ligand-receptor interaction as determined by site-directed mutagenesis, construction of receptor chimeras, and structural modeling; 5) constitutively active receptor mutants; 6) short-term (desensitization, internalization, phosphorylation) and long-term (transcription) regulations and transgenic models; 7) receptor polymorphisms.


Assuntos
Neuropeptídeos/metabolismo , Receptores de Peptídeo Intestinal Vasoativo/metabolismo , Transdução de Sinais/efeitos dos fármacos , Peptídeo Intestinal Vasoativo/metabolismo , Animais , Mapeamento Cromossômico , Regulação da Expressão Gênica/fisiologia , Humanos , Ligantes , Camundongos , Neuropeptídeos/farmacologia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Ligação Proteica , Estrutura Secundária de Proteína , Ratos , Receptores de Peptídeo Intestinal Vasoativo/genética , Receptores Tipo II de Peptídeo Intestinal Vasoativo , Receptores Tipo I de Polipeptídeo Intestinal Vasoativo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/fisiologia , Peptídeo Intestinal Vasoativo/farmacologia
11.
Br J Cancer ; 85(5): 772-9, 2001 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-11531266

RESUMO

The protease-activated receptor-2 (PAR-2) is a G protein-coupled receptor that is cleaved and activated by trypsin. We investigated the expression of PAR-2 and the role of trypsin in cell proliferation in human colon cancer cell lines. A total of 10 cell lines were tested for expression of PAR-2 mRNA by Northern blot and RT-PCR. PAR-2 protein was detected by immunofluorescence. Trypsin and the peptide agonist SLIGKV (AP2) were tested for their ability to induce calcium mobilization and to promote cell proliferation on serum-deprived cells. PAR-2 mRNA was detected by Northern blot analysis in 6 out of 10 cell lines [HT-29, Cl.19A, Caco-2, SW480, HCT-8 and T84]. Other cell lines expressed low levels of transcripts, which were detected only by RT-PCR. Further results were obtained with HT-29 cells: (1) PAR-2 protein is expressed at the cell surface; (2) an increase in intracellular calcium concentration was observed upon trypsin (1-100 nM) or AP2 (10-100 microM) challenges; (3) cells grown in serum-deprived media supplemented with trypsin (0.1-1 nM) or AP2 (1-300 microM) exhibited important mitogenic responses (3-fold increase of cell number). Proliferative effects of trypsin or AP2 were also observed in other cell lines expressing PAR-2. These data show that subnanomolar concentrations of trypsin, acting at PAR-2, promoted the proliferation of human colon cancer cells. The results of this study indicate that trypsin could be considered as a growth factor and unravel a new mechanism whereby serine proteases control colon tumours.


Assuntos
Neoplasias do Colo/metabolismo , Proteínas de Ligação a DNA/farmacologia , Proteínas de Neoplasias/metabolismo , Receptores de Trombina/metabolismo , Tripsina/farmacologia , Northern Blotting , Células CACO-2 , Cálcio/análise , Divisão Celular/efeitos dos fármacos , Neoplasias do Colo/patologia , Técnica Indireta de Fluorescência para Anticorpo , Células HT29 , Humanos , RNA Mensageiro/análise , Receptor PAR-2 , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas/efeitos dos fármacos
12.
J Endocrinol ; 169(1): 169-76, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11250658

RESUMO

We examined to what extent the abnormal glucose-dependent insulin secretion observed in NIDDM (non-insulin-dependent diabetes mellitus) is related to alterations in the handling of cytosolic Ca2+ of islets of Langerhans. Using two recognized rat models of NIDDM, the GK (Goto-Kakizaki) spontaneous model and the nSTZ (neonatal streptozotocin) induced model, we could detect several common alterations in the glucose-induced [Ca2+]i cytosolic responses. First, the initial reduction of [Ca2+]i following high glucose (16.7 mM) observed routinely in islets obtained from non-diabetic Wistar rats could not be detected in GK and nSTZ islets. Second, a delayed response for glucose to induce a subsequent 3% increase of [Ca2+]i over basal level was observed in both GK (321+/-40 s, n=11) and nSTZ (326+/-38 s, n=13) islets as compared with Wistar islets (198+/-20 s, n=11), values representing means+/-s.e.m. Third, the rate of increase in [Ca2+]i in response to a high glucose challenge was 25% and 40% lower in GK and nSTZ respectively, as compared with Wistar islets. Fourth, the maximal [Ca2+](i) level reached after 10 min of perifusion with 16.7 mM glucose was lower with GK and nSTZ islets and represented respectively 60% and 90% of that of Wistar islets. Further, thapsigargin, a blocker of Ca2+/ATPases (SERCA), abolished the initial reduction in [Ca2+]i observed in response to high glucose and induced fast [Ca2+]i oscillations with high amplitude in Wistar islets. The latter effect was not seen in GK and nSTZ islets. In these two NIDDM models, several common alterations in glucose-induced Ca2+ handling were revealed which may contribute to their poor glucose-induced insulin secretion.


Assuntos
Cálcio/metabolismo , Citosol/metabolismo , Diabetes Mellitus Experimental/metabolismo , Glucose/farmacologia , Ilhotas Pancreáticas/metabolismo , Análise de Variância , Animais , Masculino , Ratos , Ratos Endogâmicos , Ratos Wistar
13.
Diabetes ; 50 Suppl 1: S89-93, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11272210

RESUMO

The GK rat model of type 2 diabetes is especially convenient to dissect the pathogenic mechanism necessary for the emergence of overt diabetes because all adult rats obtained in our department (GK/Par colony) to date have stable basal mild hyperglycemia and because overt diabetes is preceded by a period of normoglycemia, ranging from birth to weaning. The purpose of this article is to sum up the information so far available related to the biology of the beta-cell in the GK/Par rat. In terms of beta-cell function, there is no major intrinsic secretory defect in the prediabetic GK/Par beta-cell, and the lack of beta-cell reactivity to glucose (which reflects multiple intracellular abnormalities), as seen during the adult period when the GK/Par rats are overtly diabetic, represents an acquired defect (perhaps glucotoxicity). In terms of beta-cell population, the earliest alteration so far detected in the GK/Par rat targets the size of the beta-cell population. Several convergent data suggest that the permanently reduced beta-cell mass in the GK/Par rat reflects a limitation of beta-cell neogenesis during early fetal life, and it is conceivable that some genes among the set involved in GK diabetes belong to the subset of genes controlling early beta-cell development.


Assuntos
Sobrevivência Celular , Diabetes Mellitus Tipo 2/fisiopatologia , Ilhotas Pancreáticas/fisiologia , Animais , Apoptose , Contagem de Células , DNA/metabolismo , Diabetes Mellitus Tipo 2/patologia , Feminino , Glucose/farmacologia , Transportador de Glucose Tipo 2 , Glucose-6-Fosfatase/genética , Insulina/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/efeitos dos fármacos , Leucina/farmacologia , Masculino , Índice Mitótico , Proteínas de Transporte de Monossacarídeos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar
14.
Immunity ; 14(1): 69-79, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11163231

RESUMO

Measles virus (MV) causes profound immunosuppression, resulting in high infant mortality. The mechanisms are poorly understood, largely due to the lack of a suitable animal model. Here, we report that particular MV proteins, in the absence of MV replication, could generate a systemic immunosuppression in mice through two pathways: (1) via MV-nucleoprotein and its receptor FcgammaR on dendritic cells; and (2) via virus envelope glycoproteins and the MV-hemagglutinin cellular receptor, CD46. The effects comprise reduced hypersensitivity responses associated with impaired function of dendritic cells, decreased production of IL-12, and the loss of antigen-specific T cell proliferation. These results introduce a novel model for testing the immunosuppressive potential of anti-measles vaccines and reveal a specific mechanism of MV-induced modulation of inflammatory reactions.


Assuntos
Antígenos CD/imunologia , Hemaglutininas Virais/imunologia , Imunossupressores/imunologia , Vírus do Sarampo/imunologia , Glicoproteínas de Membrana/imunologia , Nucleoproteínas/imunologia , Receptores de IgG/imunologia , Proteínas Virais de Fusão/imunologia , Proteínas Virais/imunologia , Animais , Células Apresentadoras de Antígenos/imunologia , Antígenos CD/genética , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Divisão Celular , Células Dendríticas/imunologia , Dermatite de Contato/imunologia , Dinitrofluorbenzeno/imunologia , Modelos Animais de Doenças , Hemocianinas/imunologia , Hipersensibilidade Tardia/induzido quimicamente , Hipersensibilidade Tardia/imunologia , Interleucina-12/biossíntese , Linfonodos/imunologia , Proteína Cofatora de Membrana , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas do Nucleocapsídeo , Raios Ultravioleta
15.
J Virol ; 74(3): 1373-82, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10627548

RESUMO

Measles virus (MV) infection causes acute childhood disease, associated in certain cases with infection of the central nervous system (CNS) and development of neurological disease. To develop a murine model of MV-induced pathology, we generated several lines of transgenic mice ubiquitously expressing as the MV receptor a human CD46 molecule with either a Cyt1 or Cyt2 cytoplasmic tail. All transgenic lines expressed CD46 protein in the brain. Newborn transgenic mice, in contrast to nontransgenic controls, were highly sensitive to intracerebral infection by the MV Edmonston strain. Signs of clinical illness (lack of mobility, tremors, and weight loss) appeared within 5 to 7 days after infection, followed by seizures, paralysis, and death of the infected animals. Virus replication was detected in neurons from infected mice, and virus was reproducibly isolated from transgenic brain tissue. MV-induced apoptosis observed in different brain regions preceded the death of infected animals. Similar results were obtained with mice expressing either a Cyt1 or Cyt2 cytoplasmic tail, demonstrating the ability of different isoforms of CD46 to function as MV receptors in vivo. In addition, maternally transferred immunity delayed death of offspring given a lethal dose of MV. These results document a novel CD46 transgenic murine model where MV neuronal infection is associated with the production of infectious virus, similarly to progressive infectious measles encephalitis seen in immunocompromised patients, and provide a new means to study pathogenesis of MV infection in the CNS.


Assuntos
Encéfalo/patologia , Encefalite Viral/patologia , Vírus do Sarampo/fisiologia , Sarampo/patologia , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Apoptose , Encéfalo/metabolismo , Encéfalo/virologia , Modelos Animais de Doenças , Encefalite Viral/virologia , Feminino , Humanos , Imunidade Materno-Adquirida , Sarampo/imunologia , Sarampo/virologia , Vírus do Sarampo/isolamento & purificação , Proteína Cofatora de Membrana , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Transgênicos , Gravidez , Receptores Virais/genética , Receptores Virais/metabolismo , Transgenes , Replicação Viral
17.
J Endocrinol ; 162(1): 31-7, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10396018

RESUMO

G protein alpha-subunits are involved in the transduction of receptor-mediated regulation of insulin and glucagon secretions. To get further insight into the status of G proteins in alpha- and beta-cells of the Langerhans islets, we have used immunohistochemistry to study the distribution of alpha-subunits in pancreas sections from the rat. Our results show that only insulin-immunoreactive beta-cells display immunoreactivity for selective antibodies directed against the different members of the Galphas and Galpha12-families (alphas, alphaolf, and alpha12, alpha13 respectively). Immunoreactivities for antibodies directed against members of the Galphaq- and Galphai-families showed a more diverse localization: alpha11 and alphao2 were only detected in glucagon-immunoreactive alpha-cells, whereas alphai1 was detected in all beta-cells but only in a few alpha-cells. Even though beta-cells showed immunoreactivities for alphao-non-isoform-selective antibodies, we could not identify the isoform(s) present using selective alphao1 and alphao2 antibodies. Other members of the Galphai- and Galphaq-families (alphai3, alphat2, alphaz and alphaq) were detected in both alpha- and beta-cells. In conclusion, our findings demonstrate a clear difference in the localization of G protein alpha-subunits between alpha- and beta-cells, suggesting the involvement of specific receptor transduction pathways for the neuronal/hormonal regulation of alpha- and beta-cell functions.


Assuntos
Proteínas de Ligação ao GTP/metabolismo , Ilhotas Pancreáticas/metabolismo , Animais , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP , Imuno-Histoquímica , Ratos
18.
Biochem J ; 340 ( Pt 1): 219-25, 1999 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10229678

RESUMO

Physiological concentrations of glucose that lead to Ca2+ entry and insulin secretion activate extracellular signal-regulated protein kinases (ERK1 and ERK2) in the MIN6 pancreatic beta-cell line. Here we show that this activation is inhibited by the down-regulation of protein kinase C (PKC) and by genistein, an inhibitor of protein tyrosine kinases. In contrast with results obtained in other cell types, neither the epidermal growth factor activity nor the Src family protein tyrosine kinases seem to be involved in the Ca2+-dependent activation of ERKs. inhibition of tyrosine phosphatases by vanadate leads to the activation of ERKs. As observed in the response to glucose, this activation is dependent on Ca2+ entry through L-type voltage-dependent Ca2+ channels. Thus the activation of ERKs in response to glucose depends on PKC and possibly on a tyrosine kinase/tyrosine phosphatase couple. To define the role of ERK activation by glucose we studied the regulation of transcription of the insulin gene. We found that this transcription is regulated in the MIN6 cells in the same range of glucose concentration as in primary islets, and that specific inhibition of mitogen-activated protein kinase kinase, the direct activator of ERK, impaired the response of the insulin gene to glucose. This was observed by analysis of the transfected rat insulin I gene promoter activity and a Northern blot of endogenous insulin mRNA.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/farmacologia , Insulina/genética , Ilhotas Pancreáticas/metabolismo , Animais , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/antagonistas & inibidores , Linhagem Celular , Regulação para Baixo , Ativação Enzimática/efeitos dos fármacos , Glucose/antagonistas & inibidores , Ilhotas Pancreáticas/enzimologia , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Potássio/antagonistas & inibidores , Potássio/farmacologia , Regiões Promotoras Genéticas/genética , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Transfecção , Vanadatos/antagonistas & inibidores , Vanadatos/farmacologia
19.
Ann N Y Acad Sci ; 805: 122-31; discussion 132, 1996 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-8993398

RESUMO

Glucagon and tGLP-1 receptors can be either coexpressed or selectively expressed in beta-cell models. Our results indicate that both these peptides can regulate insulin secretion from beta-cells through their own specific receptors. The finding of a selective expression of G proteins in insulin and glucagon cells indicates a clear difference in their transduction pathways. A key role of the G alpha s family in beta-cell function is further supported by its conserved cell distribution between different species. In conclusion, one could postulate that in the human beta-cells, tGLP-1 and glucagon receptors could mediate their action through different G protein alpha-subunits of the G alpha s family.


Assuntos
Adenilil Ciclases/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Ilhotas Pancreáticas/fisiologia , Receptores de Glucagon/fisiologia , Animais , Glucagon/química , Glucagon/fisiologia , Peptídeo 1 Semelhante ao Glucagon , Receptor do Peptídeo Semelhante ao Glucagon 1 , Humanos , Substâncias Macromoleculares , Especificidade de Órgãos , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/fisiologia , Precursores de Proteínas/química , Precursores de Proteínas/fisiologia , Receptores de Glucagon/biossíntese , Receptores de Glucagon/química , Transdução de Sinais
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