c-Kit signaling modulated group 3 innate lymphoid cell functions in mouse neutrophilic asthma model

Group 3 innate lymphoid cells (ILC3s) are involved in air pollution- and bacterial infection-associated neutrophilic asthma. Studies showed that asthmatic patients have higher stem cell factor (SCF) expression in airway and sera. Of note, ILC3s express SCF receptor, c-Kit, suggesting a potential role of SCF/c-Kit signaling in ILC3 functions and neutrophilic asthma. In this study, we aimed to determine whether SCF/c-Kit signaling could modulate ILC3 functions and neutrophilic asthma. Wild-type (WT) and c-Kit deficient mice (Kit w-sh) were intranasally treated with IL-1β/IL-23 or particulate matter (PM) 2.5 to induce neutrophilic asthma. While IL-1β/IL-23 or PM2.5 caused increases in neutrophil infiltration to bronchoalveolar lavage fluid (BALF) and airway hyperreactivity (AHR) in WT mice, Kit w-shmice had decreased infiltration of neutrophils and ameliorated AHR. Concomitantly, flow cytometry results showed a decreased number of IL-17+ ILC3 in the lung of Kit w-shmice compared to WT mice, which may be due to the reduced proliferation of c-Kit-deficient ILC3. In addition, we showed SCF enhanced IL-17 secretion from ILC3s in vitro. Based on re-analysis of published mouse whole lung cells scRNAseq data, we hypothesized fibroblasts are the source of SCF. Indeed, mice with SCF knockout in fibroblast exhibited decreased neutrophil infiltration and reduced IL-17+ ILC3 number in response to IL-1β/IL-23. Finally, administration of imatinib, a FDA-approved drug targeting c-Kit signaling, ameliorated AHR and ILC3 activation in the mouse neutrophilic asthma model. Taken together, our data suggested that inhibition of ILC3 activation by targeting c-Kit signaling may provide a potential therapeutic management for neutrophilic asthma.