The Study of Overexpression of Peroxiredoxin-2 Reduces MPP+-Induced Toxicity in the Cell Model of Parkinson's Disease.

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by dopaminergic neuron loss, which is related to excessive reactive oxygen species (ROS) accumulation. Endogenous peroxiredoxin-2 (Prdx-2) has potent anti-oxidative and anti-apoptotic effects. Proteomics studies revealed plasma levels of Prdx-2 were significantly lower in PD patients than in healthy individuals. For further study of the activation of Prdx-2 and its role in vitro, SH-SY5Y cells and the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) were used to model PD. ROS content, mitochondrial membrane potential, and cell viability were used to assess the effect of MPP+ in SH-SY5Y cells. JC-1 staining was used to determine mitochondrial membrane potential. ROS content was detected using a DCFH-DA kit. Cell viability was measured using the Cell Counting Kit-8 assay. Western blot detected the protein levels of tyrosine hydroxylase (TH), Prdx-2, silent information regulator of transcription 1 (SIRT1), Bax, and Bcl-2. The results showed that MPP+-induced accumulation of ROS, depolarization of mitochondrial membrane potential, and reduction of cell viability occurred in SH-SY5Y cells. In addition, the levels of TH, Prdx-2, and SIRT1 decreased, while the ratios of Bax and Bcl-2 increased. Then, Prdx-2 overexpression in SH-SY5Y cells showed significant protection against MPP+ -induced neuronal toxicity, as evidenced by the decrease in ROS content, increase in cell viability, increase in the level of TH, and decrease in the ratios of Bax and Bcl-2. Meanwhile, SIRT1 levels increase with the level of Prdx-2. This suggests that the protection of Prdx-2 may be related to SIRT1. In conclusion, this study indicated that overexpression of Prdx-2 reduces MPP+-induced toxicity in SH-SY5Y cells and may be mediated by SIRT1.

Clinical impact of Fn-induced high expression of KIR2DL1 in CD8 T lymphocytes in oesophageal squamous cell carcinoma.

BACKGROUND: To analyze the correlation between the inducing effect of Fusobacterium nucleatum (Fn) on the surface expression of the inhibitory receptor KIR2DL1 on CD8+ T cells in oesophageal squamous cell carcinoma (ESCC) and the clinicopathological features and survival prognosis and to explore its clinical significance. METHODS: The inducing effect of Fn on CD8+ T cell surface inhibitory receptor KIR2DL1 expression was analyzed in a coculture system of human CD8+ T cells and ESCC cells infected with Fn. Fn infection and the expression of KIR2DL1 on CD8+ T cells were detected by RNAscope and immunohistochemistry in ESCC tissues, and the correlations between the inducing effect of Fn on KIR2DL1 expression on CD8+ T cells and clinicopathological features were analyzed. COX regression was used to analyze the influence of each factor on the prognosis of ESCC. Survival curves were plotted by the Kaplan-Meier method, and the effect of KIR2DL1 induction on survival time was analyzed by the log-rank test. RESULTS: In the coculture system, KIR2DL1 expression on the surface of CD8+ T cells increased with increasing Fn infection time. In ESCC tissues, Fn infection was significantly correlated with high KIR2DL1 expression on CD8+ T cells. The Fn + CD8+KIR2DL1 positive patients were predominantly males who were smokers and alcohol drinkers. Moreover, patients with Fn infection were characterized by poor tumour differentiation, advanced clinical stage, and a short survival time. Meanwhile, Fn + CD8+KIR2DL1 positive group was independent risk factor affecting the prognosis of ESCC patients. CONCLUSIONS: Long-term drinking and smoking lead to an extremely unhealthy oral environment in which Fn infection and colonization are more likely to occur, thus inducing high expression of KIR2DL1 on the surface of CD8+ T cells, which can weaken the antitumour immune response and promote the malignant progression of ESCC.HIGHLIGHTSFn induced high expression of KIR2DL1 CD8+ T cells in a time-dependent manner.Fn can reduce the response of tumour cells to CDDP.The inducing effect of Fn on CD8+ T cell surface KIR2DL1 expression was significantly associated with the poor prognosis of ESCC patients.