RESUMEN
Microbial nucleic acids are critical for the induction of innate immune responses, a host defense mechanism against infection by microbes. Recent studies have indicated that double-stranded DNA (dsDNA) induces potent innate immune responses via the induction of type I IFN (IFN) and IFN-inducible genes. However, the regulatory mechanisms underlying dsDNA-triggered signaling are not fully understood. Here we show that the translocation and assembly of the essential signal transducers, stimulator of IFN genes (STING) and TANK-binding kinase 1 (TBK1), are required for dsDNA-triggered innate immune responses. After sensing dsDNA, STING moves from the endoplasmic reticulum (ER) to the Golgi apparatus and finally reaches the cytoplasmic punctate structures to assemble with TBK1. The addition of an ER-retention signal to the C terminus of STING dampens its ability to induce antiviral responses. We also show that STING co-localizes with the autophagy proteins, microtubule-associated protein 1 light chain 3 (LC3) and autophagy-related gene 9a (Atg9a), after dsDNA stimulation. The loss of Atg9a, but not that of another autophagy-related gene (Atg7), greatly enhances the assembly of STING and TBK1 by dsDNA, leading to aberrant activation of the innate immune response. Hence Atg9a functions as a regulator of innate immunity following dsDNA stimulation as well as an essential autophagy protein. These results demonstrate that dynamic membrane traffic mediates the sequential translocation and assembly of STING, both of which are essential processes required for maximal activation of the innate immune response triggered by dsDNA.
Asunto(s)
ADN/farmacología , Inmunidad Innata/efectos de los fármacos , Proteínas de la Membrana/metabolismo , Animales , Autofagia/efectos de los fármacos , Proteínas Relacionadas con la Autofagia , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Embrión de Mamíferos/citología , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Fibroblastos/ultraestructura , Ratones , Proteínas Serina-Treonina Quinasas/metabolismo , Transporte de Proteínas/efectos de los fármacos , Proteínas de Transporte VesicularRESUMEN
Vegetables are generally recognized as rich sources of dietary antioxidants for inhibiting lipid peroxidation. Here we investigated lipid hydroperoxide (LOOH)-reducing activity of several vegetables to estimate their role on the prevention of lipid peroxidation in food and the digestive tract. By using HPLC analysis, we screened vegetables possessing the ability to convert 13-hydroperoxyoctadecadienoic acid (13-HPODE) to its reduced derivative, 13-hydroxyoctadecadienoic acid (13-HODE). Welsh onion (Allium fistulosum L.) was found to be highly active in the reduction of 13-HPODE among tested vegetables. There was no relationship between 13-HPODE reducing activity and GSH peroxidase (GPX) activity in the tested vegetables. 13-HPODE-reducing activity of welsh onion was enhanced by the addition of sulfhydryl compounds including glutathione (GSH). Neither GPX inhibitor nor heat treatment suppressed 13-HPODE-reducing activity effectively. These results suggest that welsh onion and other vegetables contain GPX mimics responsible for the reduction of LOOH. GPX mimics may be helpful in the attenuation of harmful effect of LOOH from food.
Asunto(s)
Antioxidantes/metabolismo , Glutatión Peroxidasa/metabolismo , Verduras/enzimología , Antioxidantes/farmacología , Cromatografía Líquida de Alta Presión , Inhibidores Enzimáticos/farmacología , Alimentos , Glutatión Peroxidasa/antagonistas & inhibidores , Calor , Ácidos Linoleicos/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Peróxidos Lipídicos/metabolismo , Cebollas/química , Cebollas/enzimología , Oxidación-Reducción , Compuestos de Sulfhidrilo/farmacologíaRESUMEN
We attempted to determine whether docosahexaenoic acid (DHA)-induced apoptosis is mediated via the Bax-mediated pathway in human myeloid leukemia HL-60 cells. DHA-induced apoptosis was confirmed by morphological analysis and caspase-3 activation. But, cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition (MPT), did not inhibit DHA-induced Bax translocation to mitochondria or caspase-3 activation. These data suggest that DHA can induce apoptosis via the Bax-independent pathway.