Intranasally Administered Extracellular Vesicles from Adipose Stem Cells Have Immunomodulatory Effects in a Mouse Model of Asthma

Abstract

Asthma is a chronic eosinophilic airway disease characterized by type 2 helper T cell-driven inflammation. Adipose stem cells (ASCs) and the ASC culture supernatant are known to improve allergic airway inflammation; however, the immunomodulatory effects of ASC-derived extracellular vesicles (EVs) on allergic airway diseases remain unclear. Thus, we assessed the effects of ASC-derived EVs on allergic airway inflammation in a mouse model of asthma. EVs were isolated from the culture supernatant of murine ASCs and characterized. Six-week-old female C57BL/6 mice were sensitized to ovalbumin (OVA) by intraperitoneal injection and challenged intranasally with OVA. Before the OVA challenge, 10 μg/50 μl of ASC-derived EVs was administered intranasally to the experimental group. ASC-derived EVs significantly attenuated airway hyperresponsiveness (AHR) in asthmatic mice ( $p=0.023$ ). ASC-derived EVs resulted in a remarkable reduction of the total number of inflammatory cells ( $p=0.005$ ) and eosinophils ( $p=0.023$ ) in the bronchoalveolar lavage fluid (BALF), the degree of eosinophilic lung inflammation ( $p<0.001$ ), and the serum total and OVA-specific immunoglobulin (Ig)E ( $p=0.048$ and $p=0.001$ ) and total IgG1 ( $p<0.001$ ). Interleukin- (IL-) 4 was significantly inhibited with ASC-derived EV pretreatment in the BALF and lung draining lymph nodes (LLNs) ( $p=0.040$ and $p=0.011$ ). Furthermore, ASC-derived EV administration resulted in a significant increase of the regulatory T cell (Treg) populations in LLNs. ASC-derived EVs alleviated AHR and allergic airway inflammation caused by the induction of Treg expansion in a mouse model of asthma. There seems to be a role for ASC-derived EVs as a modifier in allergic airway disease.