Cross-talk of four types of RNA modification writers defines the immune microenvironment in severe asthma

RNA modifications in physiology and pathology: Progressing towards application in clinical settings

The potential to modify individual nucleotides through chemical means in order to impact the electrostatic charge, hydrophobic properties, and base pairing of RNA molecules is harnessed in the medical application of stable synthetic RNAs like mRNA vaccines and synthetic small RNA molecules. These modifications are used to either increase or decrease the production of therapeutic proteins. Additionally, naturally occurring biochemical alterations of nucleotides play a role in regulating RNA metabolism and function, thereby modulating essential cellular processes. Research elucidating the mechanisms through which RNA modifications govern fundamental cellular functions in multicellular organisms has enhanced our comprehension of how irregular RNA modification profiles can lead to human diseases. Collectively, these fundamental scientific findings have unveiled the molecular and cellular functions of RNA modifications, offering new opportunities for therapeutic intervention and paving the way for a variety of innovative clinical strategies.

Toxicarioside H-mediated modulation of the immune microenvironment attenuates ovalbumin-induced allergic airway inflammation by inhibiting NETosis

PURPOSE

Our team identified a new cardiac glycoside, Toxicarioside H (ToxH), in a tropical plant. Previous research has indicated the potential of cardenolides in mitigating inflammation, particularly in the context of NETosis. Therefore, this study sought to examine the potential of ToxH in attenuating allergic airway inflammation by influencing the immune microenvironment.

METHODS

An OVA-induced airway inflammation model was established in BALB/c mice. After the experiment was completed, serum, bronchoalveolar lavage fluid (BALF), and lung tissue samples were collected and further examined using H&E and PAS staining, flow cytometry, immunofluorescence observation, and Western blot analysis.

RESULTS

Treatment with ToxH was found to be effective in reducing airway inflammation and mucus production. This was accompanied by an increase in Th1 cytokines (IFN-γ, IL-2, and TNF-β), and the Th17 cytokine IL-17, while levels of Th2 cytokines (IL-4, IL-5, and IL-13) and Treg cytokines (IL-10 and TGF-β1) were decreased in both the bronchoalveolar lavage fluid (BALF) and the CD45+ immune cells in the lungs. Additionally, ToxH inhibited the infiltration of inflammatory cells and decreased the number of pulmonary CD44+ memory T cells, while augmenting the numbers of Th17 and Treg cells. Furthermore, the neutrophil elastase inhibitor GW311616A was observed to suppress airway inflammation and mucus production, as well as alter the secretion of immune Th1, Th2, Th17, and Treg cytokines in the lung CD45+ immune cells. Moreover, our study also demonstrated that treatment with ToxH efficiently inhibited ROS generation, thereby rectifying the dysregulation of immune cells in the immune microenvironment in OVA-induced allergic asthma.

CONCLUSIONS

Our findings indicate that ToxH could serve as a promising therapeutic intervention for allergic airway inflammation and various other inflammatory disorders. Modulating the balance of Th1/Th2 and Treg/Th17 cells within the pulmonary immune microenvironment may offer an effective strategy for controlling allergic airway inflammation.

Role and regulators of N6-methyladenosine (m6A) RNA methylation in inflammatory subtypes of asthma: a comprehensive review

Asthma is a common chronic inflammatory disease of the lungs and airway, yet its inflammatory subtypes and potential pathogenesis have not been completely elucidated and require further study. With advances in epigenetic development, methylation has emerged as a new direction for identifying and decoding the occurrence and subtype manifestations of asthma. N6-methyladenosine (m6A), an RNA methylation modification occurring in the N6-position of adenosine, is a prevalent epigenetic modification observed in eukaryotes. It exerts significant control over mRNA metabolism by regulating alternative splicing, stability, export, and translation. The dynamic process of m6A methylation plays a crucial role in the pathogenesis of asthma and is tightly regulated by three types of regulators: writers, readers, and erasers. This article provides a comprehensive review of the association between m6A regulators and the pathogenesis of inflammatory subtypes of asthma, such as involvement of inflammatory cells and related inflammatory response. Furthermore, the findings presented herein provide new insights and a solid foundation for further research on m6A mRNA methylation as biomarkers for the diagnosis and development of personalized treatment for different subtypes of asthma, particularly neutrophilic asthma and eosinophilic asthma.

Anti-CD1d treatment suppresses immunogenic maturation of lung dendritic cells dependent on lung invariant natural killer T cells in asthmatic mice

Our previous findings show that invariant natural killer T (iNKT)cells can promote immunogenic maturation of lung dendritic cells (LDCs) to enhance Th2 cell responses in asthma. It has been accepted that recognition of glycolipid antigens presented by CD1d molecules by the T cell receptors of iNKT cells leads to iNKT cell activation. Therefore, we examine the immunoregulatory influences of anti-CD1d treatment on Th2 cell response and immunogenic maturation of LDCs and subsequently explored whether these influences were dependent on lung iNKT cells in asthmatic mice. We discoveredthat in wild-type mice sensitized and challenged with house dust mite or ovalbumin (OVA), anti-CD1d treatment inhibited Th2 cell response and immunogenic maturation of LDCs. LDCs from asthmatic mice with anti-CD1d treatment had a markedly decreased influence on Th2 cell responses in vivo and in vitro. Furthermore, anti-CD1d treatment reduced the abundance and activation of lung iNKT cells in asthmatic mice. Moreover, in asthmatic iNKT cell-deficient Jα18-/- mice, anti-CD1d treatment did not influence Th2 cell responses and immunogenic maturation of LDCs. Meanwhile, the quantity of CD40L+ iNKT cells in asthmatic mice was significant decreased by anti-CD1d treatment. Finally, the inhibition of anti-CD1d treatment on LDC immunogenic maturation and Th2 cell responses in asthmatic mice was reversed by anti-CD40 treatment. Our data suggest that anti-CD1d treatment can suppress Th2 cell responses through inhibiting immunogenic maturation of LDCs dependent on lung iNKT cells, which couldbe partially related to the downregulation of CD40L expression on lung iNKT cells in asthmatic mice.

Exploration and Validation of Potential Biomarkers and Therapeutic Targets in Ferroptosis of Asthma

Purpose

Asthma is a chronic inflammatory airway disease involving multiple mechanisms, of which ferroptosis is a form of programmed cell death. Recent studies have shown that ferroptosis may play a crucial role in the pathogenesis of asthma, but no specific ferroptosis gene has been found in asthma, and the exact mechanism is still unclear. The present study aimed to screen ferroptosis genes associated with asthma and find therapeutic targets, in order to contribute a new clue for the diagnosis and therapy of asthma.

Methods

Ferroptosis-related differentially expressed genes (FR-DEGs) in asthma were selected by the GSE41861, GSE43696 and ferroptosis datasets. Next, the FR-DEGs were subjected by GO and KEGG enrichment, and the mRNA-miRNA network was constructed. Then, GSEA and GSVA enrichment analysis and Immune infiltration analysis were performed, followed by targeted drug prediction. Finally, the expression of FR-DEGs was confirmed using GSE63142 dataset and RT-PCR assay.

Results

We found 13 FR-DEGs by the GSE41861, GSE43696 and ferroptosis database. Functional enrichment analysis revealed that the 13 FR-DEGs were enriched in oxidative stress, immune response, ferroptosis, lysosome, necrosis, apoptosis etc. Moreover, our results revealed the mRNA-miRNA network of the FR-DEGs and identified candidate drugs. Also, immune infiltration revealed that ELAVL1, CREB5, CBR1 and NR1D2 are associated with the immune cells and may be potential targets in asthma. Finally, 10 FR-DEGs were validated by the GSE63142 database. It was verified that 7 FR-DEGs were differentially expressed by collecting asthma patients and healthy controls.

Conclusion

This study ultimately identified 7 FR-DEGs for the diagnosis and therapy of asthma. These 7 FR-DEGs contribute to oxidative stress and immune responses. This study provides potential therapeutic targets and biomarkers for asthma patients, shedding further light on the pathogenesis of asthma as well as providing new insights into the treatment of asthma.

m6A RNA methylation regulator-related signatures exhibit good prognosis prediction ability for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) has become the sixth most common malignant disease worldwide and is associated with high mortality, with an overall 5-year survival rate of less than 50%. Recent studies have demonstrated that aberrantly expressed m6A regulators are involved in multiple biological and pathological processes, including cancers, but the specific mechanisms of m6A regulators in HNSCC are not well elucidated. In this study, we adopted The Cancer Genome Atlas (TCGA)-HNSCC database and performed a consensus clustering analysis to classify the HNSCC samples. Least absolute shrinkage and selection operator (LASSO) regression was applied to construct an m6A signature-based HNSCC risk prediction model. Cell type identification based on estimating relative subsets of RNA transcripts (CIBERSORT) algorithms was adopted to evaluate the immune cell infiltration level in the tumor microenvironment. Based on the expression of m6A regulators in HNSCC, we identified two clusters, cluster 1 (C1) and cluster 2 (C2). C2 showed a better prognosis than C1 and was mainly enriched in the HIPPO, MYC, NOTCH, and NRF signaling pathways. We constructed an m6A signature-based risk score model and classified patients into high- and low-risk score subgroups. The high-risk-score group showed poor clinical characteristics, higher immune infiltration levels, higher chemokine and chemokine receptor expression levels, and lower immune checkpoint gene expression than the low-risk-score subgroup. In conclusion, our comprehensive analysis suggests that the m6A signature-based risk score might function as a good prognostic predictor. Our study may provide novel therapeutic clues and help predict the prognosis of HNSCC.