Cbx4 governs HIF-1α to involve in Th9 cell differentiation promoting asthma by its SUMO E3 ligase activity

The potential role of polycomb chromobox 4 (Cbx4), as a small ubiquitin-like ligase (SUMO) E3 ligase, in the development and exacerbation of asthma remains unclear. Hypoxia inducible factor-1 (HIF-1) is a key transcription factor in the cellular response to hypoxia and contributes to the pathogenesis and progression of a range of diseases, including asthma. Here, we aimed to investigate the interaction of Cbx4 with Hypoxia inducible factor-1α (HIF-1α) and the potent mechanism of action in asthma progression. In present study, in vitro and ex vivo results demonstrated that Cbx4 interacts with HIF-1α protein through its SUMO E3 ligase activity and enhances the sumoylation, which increases HIF-1 transactivation through Cbx4 and promotes the differentiation of Th9 cells, then in turn promotes the process of asthma. Treatment of inhibitors targeting SUMO E3 ligase activity of Cbx4 or HIF-1α can effectively reduce HIF-1α activation and differentiation of Th9 cells, which further attenuates the asthma in mouse model. Current results collectively demonstrated Cbx4 can govern HIF-1α to involve in Th9 cell differentiation promoting asthma by its SUMO E3 ligase activity, providing a new direction for clinical treatment of asthma.

MiR-493-5p inhibits Th9 cell differentiation in allergic asthma by targeting FOXO1

The role of micro RNAs (miRNAs) in asthma remains unclear. In this study, we examined the role of miRNA in targeting FOXO1 in asthma. Results showed that miR-493-5p was one of the differentially expressed miRNAs in the PBMCs of asthmatic children, and was also associated with Th cell differentiation. The miR-493-5p expression decreased significantly in the OVA-induced asthma mice than the control groups. The miR-493-5p mimic inhibited the expression of the IL-9, IRF4 and FOXO1, while the inhibitor restored these effects. Moreover, the Dual-Luciferase analysis results showed FOXO1 as a novel valid target of miR-493-5p. According to the rescue experiment, miR-493-5p inhibited Th9 cell differentiation by targeting FOXO1. Then the exosomes in association with the pathogenesis of asthma was identified. Various inflammatory cells implicated in asthmatic processes including B and T lymphocytes, DCs, mast cells, and epithelial cells can release exosomes. Our results demonstrated that the DC-derived exosomes can inhibit Th9 cell differentiation through miR-493-5p, thus DC-derived exosomal miR-493-5p/FOXO1/Th9 may serve as a potential therapeutic target in the development of asthma.

Foxp2 inhibits Th9 cell differentiation and attenuates allergic airway inflammation in a mouse model of ovalbumin-induced asthma

This study aimed to explore the effects of forkhead box P2 gene (Foxp2) on T-helper 9 (Th9) differentiation in asthmatic mice. An in vivo asthmatic mouse model was induced with ovalbumin (OVA). An in vitro model was established by culturing CD4⁺ T cells with TGF-β, IL-4, and anti-IFN-γ. ELISA, flow cytometry, qRT-PCR and Western blot were performed to examine IL-9 secretion, Th9 cell number, and Th9 cell transcription factor expression, respectively. Pathological changes in lung tissues and airway mucus secretion were assessed with HE and PAS glycogen staining. Anti-IL-9 mAb reversed the elevation in Th9 cells and IL-9 expression in lung tissues and bronchoalveolar lavage fluid (BALF) of asthmatic mice. Foxp2 was downregulated in BALF and lung tissue of asthmatic mice and Th9 cells. Overexpression of Foxp2 inhibited Th9 cell differentiation in vitro and improved airway inflammation in vivo. Our study suggests that overexpression of Foxp2 attenuates allergic asthma by inhibiting Th9 cell differentiation.

SGK1 enhances Th9 cell differentiation and airway inflammation through NF-κB signaling pathway in asthma

This study aimed to explore the effect of Sgk1 on Th9 differentiation and the underlying mechanism in asthma. The asthmatic mouse model induced by ovalbumin (OVA) and CD4⁺T cells which were cultured with TGF-β, IL-2, IL-4, and anti-IFN-γ were applied in vivo and in vitro, respectively. Flow cytometry, quantitative real-time PCR (qRT-PCR), and ELISA were performed to detect T-helper 9 (Th9) cells, IL-9 expression, and IL-9 release. Western blot was performed to examine phosphorylated(p)-IKKα, p-IκBα, p-p65, and IRF4 levels. Hematoxylin/eosin (H&E) staining was adopted to assess pathological changes of lung tissues. Inhibition of Sgk1 dramatically reversed elevated Th9 cells and IL-9 expression in the lung tissues of asthmatic mice. In vitro, Sgk1 promoted Th9 differentiation and elevated p-IKKα, p-IκBα, p-p65, and IRF4 levels, but inhibition of IKKα/IκBα/p65 pathway and IRF4 both reversed enhanced Th9 differentiation by Sgk1. Sgk1→IKKα/IκBα/NF-κBp65→IRF4→Th9 axis may be implicated in asthma development.

Zinc supplementation plays a crucial role in T helper 9 differentiation in allogeneic immune reactions and non-activated T cells

T helper (Th) 9 cells play a critical role in immune-mediated diseases, including allergic airway inflammation, autoimmune diseases, and cancer development. Thus, the promotion or suppression of Th9 cell differentiation, transcriptional control, and function is very important for a healthy immune system. Interestingly, T cell maturation, differentiation and function are highly dependent on the individuals' zinc status. This is especially seen in zinc deficient individuals as in the elderly population often suffering of autoimmunity and increased incidence of infections. In this regard, this study examines the impact of zinc supplementation in pharmacological doses on Th9 differentiation in two in vitro models: 1) in mixed lymphocyte cultures (MLC) displaying allogeneic activated T cells in graft versus host disease, and 2) on non-activated resting T cells in peripheral blood mononuclear cells (PBMC). On the one hand, zinc supplementation significantly diminishes IL-4-induced Th9 differentiation in MLC thereby ameliorating this pro-inflammatory allogeneic immunoreaction. On the other hand, Th9 cells are induced in resting T cells in PBMC hence triggering the immunological defense. Thus, zinc supplementation can be considered as useful additive to dampen unwanted allogeneic immunoreactions. Moreover, the pro-inflammatory immune defense in non-reactive T cells can be strengthened, which is a frequent issue in the elderly population having a weakened immune response against invading pathogens.