All hands on DEK

miR-181-5p attenuates neutrophilic inflammation in asthma by targeting DEK

We investigated the regulatory role of miR-181b-5p in neutrophilic asthma and its mechanisms by targeting DEK. DEK, matrix metalloproteinase (MMP)-2, and MMP-9 were overexpressed and the miR-181b-5p was decreased in mice with neutrophilic asthma. DEK was a direct target of miR-181b-5p. In mouse model, miR-181b-5p agomir had an inhibitory effect on airway inflammation and remodeling. miR-181b-5p inhibited DEK/p-GSK-3β^Ser9/β-catenin/MMP-9 pathway activation by regulating Wnt ligands in BEAS-2B and 16HBE cells. The ability of supernatants from human bronchial epithelial cells (hBECs) co-stimulated with CXCL8 (IL-8) and miR-181b-5p to induce NETs was weaker than that of IL-8 alone. Moreover, DEK overexpression led to excessive mitochondrial dysfunction, including DRP1 up-regulation, p-DRP1ser⁶³⁷ and MFN2 down-regulation, mitochondrial membrane potential loss, excessive mtROS generation and mitochondrial incompleteness. Interestingly, all these phenotypes were rescued by Wnt inhibitor DKK-1 and miR-181b-5p agomir. Additionally, inhibition of DRP1 with Mdivi-1 decreased MMP-9 on BEAS-2B cells. Overall, miR-181b-5p could attenuate neutrophilic asthma through inhibition of NETs release, DEK/p-GSK-3β^Ser9/β-catenin/MMP-9 pathway, DEK/Wnt/DRP1/MMP-9 and mitochondria damage. It may become a new therapeutic target for neutrophilic asthma.

GSK3-mediated phosphorylation of DEK3 regulates chromatin accessibility and stress tolerance in Arabidopsis

Chromatin dynamics enable the precise control of transcriptional programmes. The balance between restricting and opening of regulatory sequences on the DNA needs to be adjusted to prevailing conditions and is fine-tuned by chromatin remodelling proteins. DEK is an evolutionarily conserved chromatin architectural protein regulating important chromatin-related processes. However, the molecular link between DEK-induced chromatin reconfigurations and upstream signalling events remains unknown. Here, we show that ASKβ/AtSK31 is a salt stress-activated glycogen synthase kinase 3 (GSK3) from Arabidopsis thaliana that phosphorylates DEK3. This specific phosphorylation alters nuclear DEK3 protein complex composition and affects nucleosome occupancy and chromatin accessibility that is translated into changes in gene expression, contributing to salt stress tolerance. These findings reveal that DEK3 phosphorylation is critical for chromatin function and cellular stress response and provide a mechanistic example of how GSK3-based signalling is directly linked to chromatin, facilitating a transcriptional response.

DEK-targeting aptamer DTA-64 attenuates bronchial EMT-mediated airway remodelling by suppressing TGF-β1/Smad, MAPK and PI3K signalling pathway in asthma

This study is to investigate the inhibitory effects and mechanisms of DEK-targeting aptamer (DTA-64) on epithelial mesenchymaltransition (EMT)-mediated airway remodelling in mice and human bronchial epithelial cell line BEAS-2B. In the ovalbumin (OVA)-induced asthmatic mice, DTA-64 significantly reduced the infiltration of eosinophils and neutrophils in lung tissue, attenuated the airway resistance and the proliferation of goblet cells. In addition, DTA-64 reduced collagen deposition, transforming growth factor 1 (TGF-β1) level in BALF and IgE levels in serum, balanced Th1/Th2/Th17 ratio, and decreased mesenchymal proteins (vimentin and α-SMA), as well as weekend matrix metalloproteinases (MMP-2 and MMP-9) and NF-κB p65 activity. In the in vitro experiments, we used TGF-β1 to induce EMT in the human epithelial cell line BEAS-2B. DEK overexpression (ovDEK) or silencing (shDEK) up-regulated or down-regulated TGF-β1 expression, respectively, on the contrary, TGF-β1 exposure had no effect on DEK expression. Furthermore, ovDEK and TGF-β1 synergistically promoted EMT, whereas shDEK significantly reduced mesenchymal markers and increased epithelial markers, thus inhibiting EMT. Additionally, shDEK inhibited key proteins in TGF-β1-mediated signalling pathways, including Smad2/3, Smad4, p38 MAPK, ERK1/2, JNK and PI3K/AKT/mTOR. In conclusion, the effects of DTA-64 against EMT of asthmatic mice and BEAS-2B might partially be achieved through suppressing TGF-β1/Smad, MAPK and PI3K signalling pathways. DTA-64 may be a new therapeutic option for the management of airway remodelling in asthma patients.