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Identification and Characterization of Immunogenic RNA Species in HDM Allergens that Modulate Eosinophilic Lung Inflammation
Published on: May 30, 2020
Identification and Characterization of Immunogenic RNA Species in HDM Allergens that Modulate Eosinophilic Lung
Hamad H Alanazi1, Li She2, Xiao-Dong Li3
1Department of Microbiology, Immunology and Molecular Genetics, Long School of Medicine, University of Texas Health San Antonio; Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University.
Abstract:
Environmental allergens such as house dust mites (HDM) are often in complex forms containing both allergic proteins that drive aberrant type 2 responses and microbial substances that induce innate immune responses. These allergen-associated microbial components play an important role in regulating the development of type 2 inflammatory conditions such as allergic asthma. However, the underlying mechanisms remain largely undefined. The protocol presented here determines the structural characteristics and in vivo activity of allergen-associated immunostimulatory RNA. Specifically, common allergens are examined for the presence of double-stranded RNA (dsRNA) species that can stimulate IFN responses in lungs and restrain the development of severe lung eosinophilia in a mouse model of HDM-induced allergic asthma. Here, we have included the following three assays: Dot blot to show the dsRNA structures in total RNA isolated from allergens including HDM species, RT-qPCR to measure the activities of HDM RNA in interferon stimulating genes (ISGs) expression in mouse lungs and FACS analysis to determine the effects of HDM RNA on the number of eosinophils in BAL and lung, respectively.
Insights
House dust mite (HDM) allergens contain immunostimulatory RNA that can trigger interferon responses. This RNA helps reduce severe lung eosinophilia in a mouse model of allergic asthma.
Area of Science:
- Immunology
- Molecular Biology
- Allergen Research
Background:
- Environmental allergens like house dust mites (HDM) comprise proteins and microbial substances that influence immune responses.
- Allergen-associated microbial components are critical in modulating type 2 inflammatory conditions, including allergic asthma.
- The precise mechanisms by which these components regulate inflammation are not fully understood.
Purpose of the Study:
- To investigate the structural features and in vivo effects of immunostimulatory RNA found in environmental allergens.
- To determine if double-stranded RNA (dsRNA) within allergens can modulate innate immune responses and allergic inflammation.
- To analyze the impact of HDM-derived RNA on interferon (IFN) pathways and lung eosinophilia in a murine asthma model.
Main Methods:
- Dot blot analysis to detect dsRNA structures in RNA isolated from HDM and other allergens.
- Quantitative reverse transcription PCR (RT-qPCR) to assess the expression of interferon-stimulating genes (ISGs) in mouse lungs upon HDM RNA exposure.
- Flow cytometry (FACS) to quantify eosinophil levels in bronchoalveolar lavage (BAL) fluid and lung tissue.
Main Results:
- The study identified dsRNA structures within HDM RNA.
- HDM RNA was shown to stimulate ISG expression in mouse lungs, indicating activation of IFN pathways.
- Exposure to HDM RNA led to a reduction in lung eosinophilia in a mouse model of allergic asthma.
Conclusions:
- Allergen-associated RNA, specifically dsRNA, possesses immunostimulatory properties.
- HDM-derived dsRNA can activate innate immune responses via IFN stimulation.
- This RNA component plays a protective role by restraining severe lung eosinophilia in allergic asthma.
