Immunomodulation of Airway Epithelium Cell Activation by Mesenchymal Stromal Cells Ameliorates House Dust Mite–Induced Airway Inflammation in Mice

Khang M. Duong, Jaisy Arikkatt, M. Ashik Ullah, Jason P. Lynch, Vivian Zhang, Kerry Atkinson, Peter D. Sly, Simon Phipps

Allergic asthma is underpinned by T helper 2 (Th2) inflammation. Redundancy in Th2 cytokine function and production by both innate and adaptive immune cells suggests that strategies aimed at immunomodulation may prove more beneficial. Hence, we sought to determine whether administration of mesenchymal stromal cell (MSCs) to house dust mite (HDM)-sensitised mice would suppress the development of Th2 inflammation and airway hyperresponsiveness (AHR) following HDM challenge. We report that the intravenous administration of allogeneic donor MSCs one hour prior to allergen challenge significantly attenuated the features of allergic asthma, including tissue eosinophilia, Th2 cytokine (IL-5 and IL-13) levels in bronchoalveolar lavage fluid, and AHR. The number of infiltrating type 2 innate lymphoid cells was not affected by MSC transfer, suggesting that MSCs may modulate the adaptive arm of Th2 immunity. The effect of MSC administration was long-lasting: all features of allergic airways disease were significantly suppressed in response to a second round of HDM challenge 4 weeks after MSC administration. Further, we observed that MSCs decreased the release of epithelial cell-derived alarmins IL-1α and high mobility group box-1 in an IL-1 receptor antagonist-dependent manner. This in turn, significantly decreased the expression of the pro-Th2 cytokine IL-25 and reduced the number of activated and antigen-acquiring CD11c+CD11b+ dendritic cells in the lung and mediastinal lymph nodes. Our findings suggest that MSC administration can ameliorate allergic airway inflammation by blunting the amplification of epithelial-derived inflammatory cytokines induced by HDM exposure and may offer long term protection against Th2-mediated allergic airway inflammation and AHR.