House dust mites damage DNA in lung cells and worsen asthma

Published Online: May 1, 2016

Asthma affects 300 million people worldwide and is responsible for 250,000 deaths every year. In the United States, about 7.4% of adults and 8.6% of children suffer from asthma. House dust mite (HDM) is a major allergen that has been implicated in the etiology and exacerbation of asthma. Up to 85% of asthmatic patients are found to be allergic to HDM.

In a paper recently published in The Journal of Allergy & Clinical Immunology (JACI), Chan and colleagues found evidence that the health impact caused by HDM goes beyond the induction of allergic responses. In this study, the team used an experimental mouse asthma model, human lung tissues as well as human bronchial epithelial cells grown in the laboratory to study the damaging effects of HDM in allergic asthma. When DNA is damaged, DNA repair mechanisms are activated. To directly probe the importance of DNA repair in asthma, the team used a small molecule to inhibit an essential component of DNA repair in mouse and in cell lines.

The team revealed that HDM causes DNA damage, an unexpected consequence of HDM exposure that has the potential to lead to cell death and senescence. In particular, they revealed that lung epithelial cells (that line the airways) exposed to HDM produce reactive oxygen species, which are potent DNA damaging agents. Importantly, when DNA repair was inhibited, DNA damage and cell death induced by HDM were enhanced, raising the possibility that DNA repair capacity could be a novel susceptibility factor for asthma. This study reveals for the first time that HDM is a strong inducer of DNA damage in lung epithelial cells, both in vitro and in vivo, and that DNA repair has the potential to modulate asthma progression.

The results presented in this study show that HDM allergen induces genotoxicity and cytotoxicity in bronchial epithelium. Further, this work points to the possibility that patient’s DNA repair capacity may affect disease progression. New technologies point to a day when people can be screened for their DNA repair capacity, and this information could be useful in predicting asthma susceptibility. Knowledge about susceptibility factors ultimately opens doors to new avenues for disease mitigation.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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