RESUMEN
AIMS/INTRODUCTION: Resistin, secreted from adipocytes, causes insulin resistance in mice. In humans, the resistin gene is mainly expressed in monocytes and macrophages. Tunicamycin is known to induce endoplasmic reticulum (ER) stress, and reduce resistin gene expression in 3T3-L1 mouse adipocytes. The aim of the present study was to examine whether ER stress affects resistin gene expression in human monocytes. MATERIALS AND METHODS: The relationship between resistin messenger ribonucleic acid (mRNA) and ER stress markers mRNA was analyzed by reverse transcription polymerase chain reaction in isolated monocytes of 30 healthy volunteers. The effect of endotoxin/lipopolysaccharides or tunicamycin on resistin gene expression was analyzed in THP-1 human monocytes. Signaling pathways leading to resistin mRNA were assessed by the knockdown using small interfering RNA or overexpression of key molecules involved in unfolded protein response. RESULTS: Resistin mRNA was positively associated with immunoglobulin heavy chain-binding protein (BiP) or CAAT/enhancer binding protein-α homologous protein (CHOP) mRNA in human isolated monocytes. In THP-1 cells, lipopolysaccharides increased mRNA of BiP, pancreatic endoplasmic reticulum eukaryotic initiation factor 2α kinase (PERK) and CHOP, as well as resistin. Tunicamycin also increased resistin mRNA. This induction appeared to be dose- and time-dependent. Tunicamycin-induced resistin mRNA was inhibited by chemical chaperone, 4-phenylbutyric acid. The knockdown of either PERK, activating transcription factor 4 (ATF4) or CHOP reduced tunicamycin-induced resistin mRNA. Conversely, overexpression of ATF4 or CHOP increased resistin mRNA. CONCLUSIONS: Endoplasmic reticulum stress induced by tunicamycin increased resistin mRNA through the PERK-ATF4-CHOP pathway in THP-1 human monocytes. ER stress could lead to insulin resistance through enhanced resistin gene expression in human monocytes.
Asunto(s)
Factor de Transcripción Activador 4/metabolismo , Estrés del Retículo Endoplásmico , Monocitos/metabolismo , Resistina/metabolismo , Factor de Transcripción CHOP/metabolismo , eIF-2 Quinasa/metabolismo , Adulto , Línea Celular , Femenino , Expresión Génica , Humanos , Masculino , ARN Mensajero/metabolismo , Resistina/genética , Transducción de Señal , Tunicamicina/toxicidad , Adulto JovenRESUMEN
In this article, we review studies of generalized self-efficacy (GSE) involving the characteristics, measurement, changes, and formation of GSE. We discuss controversial issues regarding developmental changes in GSE, such as the age at which GSE develops and becomes established, and its causal direction, i.e., does task-specific self-efficacy have an effect on GSE, or does GSE have an effect on task-specific self-efficacy. We suggest that studies of GSE should be designed to address these questions. Since it is possible to study the long-term development of GSE using epigenetic theory, we suggest that this theory should be the theoretical framework for GSE studies. GSE studies would also benefit from consideration of the theory of competence (concept of virtue) based on the perspective of healthy ego-development. Moreover, not only positive aspects of GSE, but also negative aspects, such as over-aspiration, should be investigated. We conclude that multifaceted studies of GSE based on theories of personality development should be undertaken.