Cigarette smoke extract promotes DNA methyltransferase 3a expression in dendritic cells, inducing Th‐17/Treg imbalance via the c‐Jun/allograft inflammatory factor 1 axis

Abstract

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disorder.Although numerous studies on COPD have been conducted, therapeutic strategies for COPD are limited, and its pathological mechanism is still unclear. The present study aimed to explore the role of DNA methyltransferase 3a (DNMT3a) in dendritic cells (DCs) and the possible role of the Th-17/Treg cell balance in COPD. Immature DCs (iDCs) were induced and cocultured with CD4 + T cells. An in vitro COPD model was established by treatment with cigarette smoke extract (CSE). DNMT3a or allograft inflammatory factor 1 (AIF1) and c-Jun N-terminal kinase (JNK) were inhibited and overexpressed, respectively, by transfection with sh-DNMT3a or sh-AIF1 and JNK overexpression plasmids. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability. The Th17/Treg cell ratio was determined by flow cytometry. The expression levels of DNMT3a, c-Jun and AIF1 were measured using RT-qPCR or western blotting. Chromatin immunoprecipitation (CHIP) was used to confirm the interaction between c-Jun and the AIF1 promoter region. CSE stimulation promoted the expression of DNMT3a, and AIF1, and the ratio of p-c-Jun/c-Jun in iDCs. Besides, the iDC-mediated differentiation of Th17 cells was in a dose-dependent manner. However, knockdown of DNMT3a or AIF1 reversed the above effects caused by CSE. Inhibition of c-Jun signaling by treatment with the JNK inhibitor SP600125 also suppressed the iDC-mediated differentiation of Th17 cells, which was promoted by CSE. CHIP analysis showed that c-Jun could bind to the promoter region of AIF1. DNMT3a could regulate the iDC-mediated Th17/Treg balance by regulating the c-Jun/AIF1 axis.

Shema Oral Liquid Ameliorates the Severity of LPS-Induced COPD via Regulating DNMT1

“…The inhibitions of DNMTs and Notch pathway suppressed inflammatory response and cellular apoptosis in a cell model of COPD ( Qiu et al, 2018 ). Cigarette smoke extract treatment also promoted the expression of DNMT3A in dendritic cells of COPD mouse models, and DNMT3A regulated Th17/Treg cell balance via c-Jun/AIF1 axis ( Huang et al, 2021 ). Our study further illustrated that DNMT1 was significantly increased in the lung tissue of COPD rats, which may generate novel mechanistic insight into therapeutic targets for the treatment of COPD.…”

Porphyromonas gingivalis exacerbates alcoholic liver disease by altering gut microbiota composition and host immune response in mice

“…Liver and colon proteins were extracted using a radioimmunoprecipitation assay kit (Thermo Fisher Scientific, Waltham, MA, USA). Western blot was performed as previously described (Huang et al, 2021). Membrane protein bands were visualized using an electrochemiluminescence detection system (Tianneng, Shanghai, China) and grey‐scale quantification of the protein bands was performed using ImageJ.…”

“…Liver and colon proteins were extracted using a radioimmunoprecipitation assay kit (Thermo Fisher Scientific, Waltham, MA, USA). Western blot was performed as previously described (Huang et al, 2021).…”

AIF1: Function and Connection with Inflammatory Diseases

“…Additionally, AIF1 inhibition can inhibit antigen-specific CD8+ T-cell activation, limiting CXCR3, IFN-γ and granzyme B expression and proliferation and, in turn, expanding IL-10-producing CD8+ CD122+ PD-1+ regulatory T cells [69]. Moreover, DNA methyltransferase 3a expression in DCs is involved in the regulation of T H17 /T reg cells polarization through the c-Jun/AIF1 axis, because c-Jun can bind to the promoter of AIF1 [70]. Finally, AIF1 modulates interferon regulatory factor 8 (IRF8) and transcription factor RelB (by interaction with protein kinase C (PKC) to promote NF-κB and MAPK signaling and drive hematopoietic stem cell differentiation into classical DC type 1 (cDC1) subsets and monocyte-derived DC (Mo-DC) under Fms-related tyrosine kinase 3-ligand (Flt3-L) and granulocyte macrophage-colony stimulatory factor (GM-CSF) stimuli, respectively [71].…”