RESUMO
The malate shuttle is traditionally understood to maintain NAD+/NADH balance between the cytosol and mitochondria. Whether the malate shuttle has additional functions is unclear. Here we show that chronic viral infections induce CD8+ T cell expression of GOT1, a central enzyme in the malate shuttle. Got1 deficiency decreased the NAD+/NADH ratio and limited antiviral CD8+ T cell responses to chronic infection; however, increasing the NAD+/NADH ratio did not restore T cell responses. Got1 deficiency reduced the production of the ammonia scavenger 2-ketoglutarate (2-KG) from glutaminolysis and led to a toxic accumulation of ammonia in CD8+ T cells. Supplementation with 2-KG assimilated and detoxified ammonia in Got1-deficient T cells and restored antiviral responses. These data indicate that the major function of the malate shuttle in CD8+ T cells is not to maintain the NAD+/NADH balance but rather to detoxify ammonia and enable sustainable ammonia-neutral glutamine catabolism in CD8+ T cells during chronic infection.
Assuntos
Ácidos Cetoglutáricos , NAD , Humanos , Oxirredução , NAD/metabolismo , Ácidos Cetoglutáricos/metabolismo , Amônia , Malatos/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Infecção Persistente , AntiviraisRESUMO
Protective effect of Tagetes erecta flowers essential oils was investigated on oxidative stress, immune response, inflammation, and apoptosis against N-methyl-N'nitro-N-nitroguanidine (MNNG) induced gastric cancer in rats. Essential oil were extracted from Tagetes erecta flowers and analyzed using gas chromatography-mass spectrometry (GC-MS). For observing a protective effect against MNNG induced gastric cancer, we divided rats into 4 groups (group A to D) having 10 rats in each group. Performed various experiments and measured a different parameters to investigate antioxidant activity, immune response, anti-inflammatory and anti-apoptotic activity. The levels of malondialdehyde were markedly increased in the presence of N-methyl-N'nitro-N-nitroguanidine, whereas, the antioxidant activities of superoxide dismutase, and catalase were lowered in the treated rats in contrast with the control. Intervention with TEEO to gastric cancer-induced rats upregulated the redox status and the activity of the immune system to decrease cancer risk. The proinflammatory cytokines (IL-6 and TNF-α) secretions that were induced by MNNG were markedly inhibited by TEEO. Administration of TEEO also significantly reduced terminal deoxynucleotidyl transferase dUTP nick end labeling positive gastric cancer cells, expression of mRNA of caspase-3, and Bax. Whereas, the expression of Bcl-2 was increased. Additionally, downregulation of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) and IκBα degradation and the nuclear factor-κB (NF-κB) p65 expression in tissues of the stomach of MNNG-induced-rats were markedly elevated due to TEEO. This suggested possession of TEEO with a protective shield against MNNG induced gastric cancer by the exertion of antioxidative stress, anti-apoptotic response, the anti-inflammatory response through Nrf2/HO-1, and NF-κB signaling pathways.
Assuntos
Flores , Heme Oxigenase (Desciclizante) , Inibidor de NF-kappaB alfa , Proteínas de Neoplasias , Proteínas de Transporte Nucleocitoplasmático , Neoplasias Gástricas , Tagetes , Animais , Masculino , Camundongos , Ratos , Antioxidantes/metabolismo , Apoptose , Catalase/metabolismo , Linhagem Celular Tumoral , Flores/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Guanidinas , Heme Oxigenase (Desciclizante)/metabolismo , Imunoglobulina A/química , Imunoglobulina G/química , Imunoglobulina M/química , Inflamação , Metilnitronitrosoguanidina/química , Proteínas de Neoplasias/metabolismo , Inibidor de NF-kappaB alfa/metabolismo , Proteínas de Transporte Nucleocitoplasmático/metabolismo , Óleos Voláteis/química , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos Wistar , Transdução de Sinais , Neoplasias Gástricas/metabolismo , Tagetes/metabolismo , Fator 2 Relacionado a NF-E2RESUMO
Berberine, an alkaloid derivative from Berberis vulgaris L., has been used extensively in traditional Chinese medicine to treat diarrhea and diabetes, but the underlying mechanisms for treating diabetes are not fully understood. Recent studies suggested that berberine has many beneficial biological effects, including anti-inflammation. Because type 1 diabetes is caused by T cell-mediated destruction of beta cells and severe islet inflammation, we hypothesized that berberine could ameliorate type 1 diabetes through its immune regulation properties. Here we reported that 2 weeks of oral administration of berberine prevented the progression of type 1 diabetes in half of the NOD mice and decreased Th17 and Th1 cytokine secretion. Berberine suppressed Th17 and Th1 differentiation by reducing the expression of lineage markers. We found that berberine inhibited Th17 differentiation by activating ERK1/2 and inhibited Th1 differentiation by inhibiting p38 MAPK and JNK activation. Berberine down-regulated the activity of STAT1 and STAT4 through the suppression of p38 MAPK and JNK activation, and it controlled the stability of STAT4 through the ubiquitin-proteasome pathway. Our findings indicate that berberine targets MAPK to suppress Th17 and Th1 differentiation in type 1 diabetic NOD mice. This study revealed a novel role of ERK in Th17 differentiation through down-regulation of STAT3 phosphorylation and RORgamma t expression.