RESUMO
INTRODUCTION AND OBJECTIVES: MicroRNA-326 is abnormally expressed in autoimmune diseases, but its roles in autoimmune hepatitis (AIH) are unknown. In this study, we aimed to investigate the effect of miR-326 on AIH and the underlying mechanism. MATERIALS AND METHODS: Concanavalin A was administrated to induce AIH in mice and the expression levels of miR-326 and TET2 was evaluated by qRT-PCR and western blot, respectively. The percentages of Th17 and Treg cells were evaluated by flow cytometry and their marker proteins were determined by western blot and ELISA. The mitochondrial membrane potential (MMP) and ROS level were tested with the JC-1 kit and DCFH-DA assay. The binding relationships between miR-326 and TET2 were verified by dual-luciferase reporter assay. The liver tissues were stained by the HE staining. In vitro, AML12 cells were cocultured with mouse CD4+T cells. The expression levels of pyroptosis-related proteins were assessed by western blot. RESULTS: Concanavalin A triggered AIH and enhanced the expression level of miR-326 in mice. It increased both Th17/Treg ratio and the levels of their marker proteins. The expression of TET2 was decreased in AIH mice. Knockdown of miR-326 could decrease the levels of pyroptosis-related proteins, the ROS level and increase MMP. In mouse CD4+T cells, miR-326 sponged TET2 to release IL-17A. Coculture of AML12 cells with isolated CD4+T cells from miR-326 knockdown AIH mice could relieve pyroptosis. CONCLUSIONS: Knockdown of miR-326 exerted anti-pyroptosis effects via suppressing TET2 and downstream NF-κB signaling to dampen AIH. We highlighted a therapeutic target in AIH.
Assuntos
Hepatite A , Hepatite Autoimune , MicroRNAs , Animais , Camundongos , Concanavalina A/farmacologia , Concanavalina A/metabolismo , Hepatite Autoimune/genética , Hepatócitos/metabolismo , MicroRNAs/metabolismo , Piroptose , Espécies Reativas de Oxigênio/metabolismo , Linfócitos T Reguladores/metabolismoRESUMO
BACKGROUND: New sequencing technologies have enabled the identification of mutations in Ten-eleven-translocation 2 (TET2), an enzyme that catalyzes the conversion of 5-methylcytosine into 5-hydroxymethylcytosine (5-hmC) in myeloid neoplasms. We have recently identified reduced TET2 mRNA expression in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML), which is associated with a poor overall survival in MDS. We herein aimed to investigate TET2 mutations and their impact on TET2 expression in a cohort of patients with myeloid neoplasms, including MDS and AML patients. FINDINGS: TET2 mutations were observed in 8 out of 19 patients (42 %) with myeloid neoplasms. The TET2 expression profile was similar between in wild type and in TET2 mutated patients. CONCLUSION: Our results suggest that TET2 expression is reduced in MDS/AML patients, independently of mutational status.
Assuntos
Biomarcadores Tumorais/genética , Proteínas de Ligação a DNA/genética , Leucemia Mieloide Aguda/genética , Mutação , Síndromes Mielodisplásicas/genética , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/genética , Adulto , Idoso , Biomarcadores Tumorais/análise , Estudos de Casos e Controles , Análise Mutacional de DNA , Proteínas de Ligação a DNA/análise , Dioxigenases , Regulação para Baixo , Feminino , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Leucemia Mieloide Aguda/enzimologia , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Síndromes Mielodisplásicas/enzimologia , Síndromes Mielodisplásicas/patologia , Proteínas Proto-Oncogênicas/análiseRESUMO
TET2, a member of the ten-eleven-translocation (TET) family genes that modify DNA by converting 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC), is located in chromosome 4q24 and is frequently mutated in myeloid malignancies. The impact of TET2 mutation on survival outcomes is still controversial; however, functional studies have proved that it is a loss-of-function mutation that impairs myeloid cell differentiation and contributes to the phenotype of myeloid neoplasia. We, herein, aimed to investigate TET2 expression in patients with myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). A significantly decreased TET2 expression was observed in bone marrow cells from AML (n = 53) and patients with MDS (n = 64), compared to normal donors (n = 22). In MDS, TET2 expression was significantly reduced in RAEB-1/RAEB-2 compared to other WHO 2008 classifications, and a lower TET2 expression was observed at the time of MDS disease progression in four of five patients. In multivariate analysis, low TET2 expression (P = 0.03), male gender (P = 0.02), and WHO 2008 classification (P < 0.0001) were independent predictors of poorer overall survival. These results suggest that defective TET2 expression plays a role in the MDS pathophysiology and predicts survival outcomes in this disease.