The multiple roles of mite allergens in allergic diseases

Dermatophagoides farinae microRNAs released to external environments via exosomes regulate inflammation-related gene expression in human bronchial epithelial cells

Background

Dermatophagoides farinae (DFA) is an important species of house dust mites (HDMs) that causes allergic diseases. Previous studies have focused on allergens with protein components to explain the allergic effect of HDMs; however, there is little knowledge on the role of microRNAs (miRNAs) in the allergic effect of HDMs. This study aimed to unravel the new mechanism of dust mite sensitization from the perspective of cross-species transport of extracellular vesicles-encapsulated miRNAs from HDMs.

Methods

Small RNA (sRNA) sequencing was performed to detect miRNAs expression profiles from DFA, DFA-derived exosomes and DFA culture supernatants. A quantitative fluorescent real-time PCR (qPCR) assay was used to detect miRNAs expression in dust specimens. BEAS-2B cells endocytosed exosomes were modeled in vitro to detect miRNAs from DFA and the expression of related inflammatory factors. Representative dfa-miR-276-3p and dfa-novel-miR2 were transfected into BEAS-2B cells, and then differentially expressed genes (DEGs) were analyzed by RNA sequencing. Protein-protein interaction (PPI) network analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) terms enrichment analyses were performed on the first 300 nodes of DEGs.

Results

sRNA sequencing identified 42 conserved miRNAs and 66 novel miRNAs in DFA, DFA-derived exosomes, and DFA culture supernatants. A homology analysis was performed on the top 18 conserved miRNAs with high expression levels. The presence of dust mites and miRNAs from HDMs in living environment were also validated. Following uptake of DFA-derived exosomes by BEAS-2B cells, exosomes transported miRNAs from DFA to target cells and produced pro-inflammatory effects in corresponding cells. RNA sequencing identified DEGs in dfa-miR-276-3p and dfa-novel-miR2 transfected BEAS-2B cells. GO and KEGG enrichment analyses revealed the role of exosomes with cross-species transporting of DFA miRNAs in inflammatory signaling pathways, such as JAK-STAT signaling pathway, PI3K/AKT signaling pathway and IL-6-mediated signaling pathway.

Conclusion

Our findings demonstrate the miRNAs expression profiles in DFA for the first time. The DFA miRNAs are delivered into living environments via exosomes, and engulfed by human bronchial epithelial cells, and cross-species regulation may contribute to inflammation-related processes.

Environmental influences on childhood asthma: Climate change

Climate change is a key environmental factor for allergic respiratory diseases, especially in childhood. This review describes the influences of climate change on childhood asthma considering the factors acting directly, indirectly and with their amplifying interactions. Recent findings on the direct effects of temperature and weather changes, as well as the influences of climate change on air pollution, allergens, biocontaminants and their interplays, are discussed herein. The review also focusses on the impact of climate change on biodiversity loss and on migration status as a model to study environmental effects on childhood asthma onset and progression. Adaptation and mitigation strategies are urgently needed to prevent further respiratory diseases and human health damage in general, especially in younger and future generations.

Sublingual immunotherapy with Dermatophagoides farinae drops for pediatric atopic dermatitis

BACKGROUND

We evaluated the clinical effect and safety of sublingual immunotherapy (SLIT) with Dermatophagoides farinae drops for pediatric atopic dermatitis (AD).

METHODS

We enrolled children aged 4-13 years with AD and grouped them into the SLIT and control groups using the random number table method. We subdivided each group based on treatment duration (1-, 2-, and 3-year subgroups). The SLIT group received Dermatophagoides farinae drops, and both groups received conventional treatment (topical glucocorticoids, skin moisturizers, oral antihistamines, and allergen avoidance). Effective rate and effect were compared between groups after 1, 2, and 3 years of treatment.

RESULTS

We assessed 309 SLIT cases (male, 192; age, 4-13 years) and 131 controls (male, 79; age 4-13 years). The effective rate and curative effect after 2 and 3 years of treatment were significantly different between the groups (P < 0.05). The effect and effective rates between corresponding SLIT and control group treatment duration subgroups were significantly different (P < 0.05). SLIT group duration subgroups showed significant differences in the effect and effective rates (P < 0.05). Posttreatment Scoring Atopic Dermatitis (SCORAD) scores in the SLIT group duration subgroups were significantly lower than those of the corresponding control subgroups (P < 0.05). Upon follow-up at 1 year post treatment completion, the SLIT group's SCORAD score was significantly lower than its baseline score and the control group's follow-up score (P < 0.05).

CONCLUSION

SLIT with Dermatophagoides farinae drops for pediatric AD is safe and effective; effectiveness is maintained after treatment cessation, and prolonged treatment improves efficacy.