Résumé
Hyperhomocysteinemia (HHcy) accelerates atherosclerosis by increasing proliferation and stimulating cytokine secretion in T cells. However, whether homocysteine (Hcy)-mediated T cell activation is associated with metabolic reprogramming is unclear. Here, our in vivo and in vitro studies showed that Hcy-stimulated splenic T-cell activation in mice was accompanied by increased levels of mitochondrial reactive oxygen species (ROS) and calcium, mitochondrial mass and respiration. Inhibiting mitochondrial ROS production and calcium signals or blocking mitochondrial respiration largely blunted Hcy-induced T-cell interferon γ (IFN-γ) secretion and proliferation. Hcy also enhanced endoplasmic reticulum (ER) stress in T cells, and inhibition of ER stress with 4-phenylbutyric acid blocked Hcy-induced T-cell activation. Mechanistically, Hcy increased ER-mitochondria coupling, and uncoupling ER-mitochondria by the microtubule inhibitor nocodazole attenuated Hcy-stimulated mitochondrial reprogramming, IFN-γ secretion and proliferation in T cells, suggesting that juxtaposition of ER and mitochondria is required for Hcy-promoted mitochondrial function and T-cell activation. In conclusion, Hcy promotes T-cell activation by increasing ER-mitochondria coupling and regulating metabolic reprogramming.
Sujets)
Animaux , Femelle , Souris , Calcium , Métabolisme , Prolifération cellulaire , Cellules cultivées , Réticulum endoplasmique , Métabolisme , Stress du réticulum endoplasmique , Endoribonucleases , Métabolisme , Homocystéine , Toxicité , Interféron gamma , Génie métabolique , Souris de lignée C57BL , Mitochondries , Métabolisme , Nocodazole , Pharmacologie , Phénylbutyrates , Pharmacologie , Protein-Serine-Threonine Kinases , Métabolisme , Protéines proto-oncogènes c-akt , Métabolisme , Espèces réactives de l'oxygène , Métabolisme , Lymphocytes T , Biologie cellulaire , Métabolisme , eIF-2 Kinase , MétabolismeRésumé
OBJECTIVE:To explore a new extraction method of baicalin. METHODS: A new continuous circular extraction equipment was adopted to extract baicalin. L9(43) orthogonal experiment was conducted to optimize the extraction process taking the content of total flavonoids as index with the number of period of batching cycle of solvent, extraction temperature and distillation time as factors. The new continuous circular extraction was compared with the aqueous extraction and acidic deposition method in terms of the yield of extractum, content of total flavonoids and baicalin content and the color of the extract. RESULTS: The best technical conditions for the new extraction method of baicalin were as follows: 2.5 periods in batching cycle of solvent, 50 ℃ in extraction temperature, and 6 h in distillation time. The new continuous circular extraction was significantly better than the aqueous extraction in terms of contents of total flavonoids and baicalin and the color of the extract. CONCLUSION: The new continuous circular extraction method is applicable for the extraction of baicalin.