PM2.5 exposure and cold stress exacerbates asthma in mice by increasing histone acetylation in IL-4 gene promoter in CD4+ T cells

Abstract Abstract 519 We have previously shown that the pan-HDAC inhibitors LAQ824 and LBH589 inhibit IL-10 production in APCs, rendering these cells more inflammatory and capable of effectively priming naïve antigen-specific CD4+ T-cells and restoring the responsiveness of tolerant T-cells1. These findings led us to explore which HDAC(s) might be involved in the regulation of IL-10 gene transcription and be the putative target(s) of HDI-mediated IL-10 inhibition. To answer these questions we subjected the macrophage cell line RAW264.7 to shRNA screening using specific shRNAs to knockdown each known HDAC. We found that among all the HDACs, knocking down HDAC6 (HDAC6KD) was associated with a significant decrease in IL-10 mRNA and protein in response to LPS stimulation. Furthermore, HDAC6KD clones display an enhanced expression of the co-stimulatory molecule B7.2. Functionally, HDAC6KD cells were better activators of anti-HA (hemagglutinin-influenza) transgenic CD4+ T cells, leading to significantly enhanced production of IL-2 and IFN-g in response to cognate antigen. More importantly, anti-HA CD4+ anergic T cells isolated from animals bearing HA-expressing A20 B-cell lymphoma regained their ability to produce IL-2 and IFN-g when cultured in vitro with HDAC6KD cells. These results have been confirmed in APCs isolated from HDAC6 knock-out mice and in wild type APCs treated in vitro with isotype-selective HDAC6 inhibitors. Given that HDACs do not bind to DNA and they need to interact with transcription factors to regulate gene expression, we investigate next which transcription factor(s) HDAC6 might be associated with, to regulate IL-10 transcriptional activity. One likely candidate was Stat3, a well-known transcriptional activator of IL-10 gene expression that we have previously shown to play a central role in tolerance induction by APCs2. By co-immunoprecipitation studies we found that HDAC6 indeed interacts physically with Stat3. Of note, knocking down HDAC6 in APCs resulted in absence of Stat3 phosphorylation and decreased recruitment of Stat3 to the IL-10 gene promoter which might explain the inability of HDAC6KD cells to produce IL-10. The additional findings that IL-10 production by HDAC6KD cells was restored when these cells were transfected with a constitutively active mutant version of Stat3 (Stat3c) provides additional support for the important role of HDAC6 upon Stat3 activation. Further confirmation for a concerted regulatory mechanism involving HDAC6 and Stat3 in IL-10 gene regulation was provided by studies using CPA-7, a specific Stat3 inhibitor that disrupts Stat3 recruitment and binding to gene promoters. As expected, a complete abrogation of Stat3 recruitment to the IL-10 gene promoter was observed in CPA-7 treated APCs. Interestingly, such an effect was accompanied by a parallel decrease in HDAC6 recruitment to the IL-10 promoter and inhibition of IL-10 gene transcriptional activity. Taken together, we have shown for the first time that HDAC6 interacts physically with Stat3 and is required for its phosphorylation. Since Stat3 phosphorylation is absolutely necessary for activation of Stat3 target genes, HDAC6 inhibition is an enticing molecular approach to disrupt the Stat3/IL-10 axis and overcome tolerogenic mechanisms in APCs. Disclosures: No relevant conflicts of interest to declare.

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Correction: Changes in histone acetylation and methylation that are important for persistent but not transient expression of CCR4 in human CD4+ T cells

European Journal of Immunology ◽

10.1002/eji.201190055 ◽

2011 ◽

Vol 41 (9) ◽

pp. 2793-2793

Author(s):

Satya P. Singh ◽

Maristela M. de Camargo ◽

Hongwei H. Zhang ◽

John F. Foley ◽

Michael N. Hedrick ◽

...

Keyword(s):

T Cells ◽

Histone Acetylation ◽

Transient Expression ◽

Cd4 T Cells

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The assessment of histone acetylation marks in the vicinity of transcription factor binding sites in human CD4 + T cells using information theory methods

Computational Biology and Chemistry ◽

10.1016/j.compbiolchem.2020.107232 ◽

2020 ◽

Vol 86 ◽

pp. 107232

Author(s):

Nafiseh Banirazi Motlagh ◽

Bahram Mohammadpour Esfahani ◽

Behnoosh Ashrafi ◽

Fatemeh Zare-Mirakabad

Keyword(s):

Information Theory ◽

T Cells ◽

Transcription Factor ◽

Histone Acetylation ◽

Binding Sites ◽

Cd4 T Cells ◽

Transcription Factor Binding Sites ◽

Transcription Factor Binding ◽

Factor Binding

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P148 Differential methylation of the TNF gene promoter, potential for the development of a diagnostic biomarker for RA

Rheumatology ◽

10.1093/rheumatology/keab247.144 ◽

2021 ◽

Vol 60 (Supplement_1) ◽

Author(s):

Rujiraporn Pitaksalee ◽

Paul Emery ◽

Richard Hodgett ◽

Frederique Ponchel

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Tissue Bank ◽

Gene Promoter ◽

Classification Performance ◽

Differential Methylation ◽

Diagnostic Biomarker ◽

Clinical Model ◽

Early Ra ◽

Tnf Gene

Abstract Background/Aims Diagnosing rheumatoid arthritis (RA) early is difficult despite the use of anti-citrullinated protein antibodies in the new EULAR-2010 classification criteria, particularly for antibody-negative patients. Alterations in epigenetic patterns have been associated with RA CD4+T-cells at the TNF gene locus (1). The second aim of my PhD project was to select a CpG site to develop a quantitative methylation sensitive PCR (qMSP) assay as a diagnostic biomarker test for RA classification. Methods Patients attending an early arthritis clinic were used (with full ethical approval). An 450K Illumina methylation genome-wide dataset analysing DNA from CD4+T-cells identified CpG on TNF promoter region as a differentially methylated CpG between controls and RA patients (1). A qMSP assay was designed using a TaqMan approach (primers and probe), using a reference gene (GAPHD) for normalisation. The assay was validated in DNA extracted from PBMC. The performance of the assay for RA classification was accessed using binary logistic regression. Results We noted differences in levels of methylation in CD4+T-cells in RA, notably affecting the TNF gene promoter in about 15% of cells. We validated this using bisulphite sequencing showing about 30% of cells with differential methylation in early RA compared to controls. This allowed us to select cg11484872, cg21370522, and cg01569083 as candidates. We optimised a qMSP assay using fully methylated/un-methylated DNA. PBMC samples were retrieved from our tissue bank for 65 early RA, and 64 non-RA patients (including 11 reactive arthritis, 37 undifferentiated arthritis, and 16 psoriatic arthritis). The methylation levels (%) detected by the TNF-qMSP assay were significantly lower in RA (Δ-DM =-10.28%, p = 7x10-7). The loss of TNF promoter gene methylation was associated with RA classification (p < 0.0001, unadjusted OR = 0.900 (95% CI: 0.85-0.94)) with a good classification performance (AUROC = 0.76 (95% CI: 0.67, 0.84)). An adjusted regression model using the demographic and clinical parameters associated with RA classification in this group of patients (age, smoking, counts for tender and swollen joints) showed that adding TNF to the clinical model improved the model’s performance (increasing AUROC from 0.86 , to 0.91). Comparing classification accuracy, adding the TNF-qMSP resulted in an increased correct classification of 5.7 % compared to the clinical model. A similar result was obtained in the antibody negative patients, with TNF-qMSP assay improving the model’s classification from AUROC 0.91 to 0.96 and 3.3% more patients correctly classified. Conclusion The loss of DNA methylation on the TNF gene promoter identified in early RA patients provided a valuable target for a biomarker assay development. The results will need to be confirmed in a larger cohort but the TNF-qMSP assay offers good opportunities for RA versus non-RA classification particular in antibody negative disease. Disclosure R. Pitaksalee: Grants/research support; ROYAL THAI GOVERNMENT SCHOLARSHIP. P. Emery: None. R. Hodgett: None. F. Ponchel: None.

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