Paraoxonase-1 Is a Pivotal Regulator Responsible for Suppressing Allergic Airway Inflammation Through Adipose Stem Cell-Derived Extracellular Vesicles

Although adipose stem cell (ASC)-derived extracellular vesicles (EVs) are as effective as ASCs in the suppression of Th2 cell-mediated eosinophilic inflammation, the role of identified pulmonary genes has not been well documented. Thus, we assessed the immunomodulatory effects of paraoxonase-1 (PON1) on allergic airway inflammation in a mouse model of asthma. Five-week-old female C57BL/6 mice were sensitized to ovalbumin (OVA) by intraperitoneal injection and challenged intranasally with OVA. To evaluate the effect of PON1 on allergic airway inflammation, the intranasal and intraperitoneal injections of recombinant mouse serum PON1 (5 μg/50 μL) were performed before the OVA challenge. We evaluated airway hyperresponsiveness (AHR), total inflammatory cells, and eosinophils in the bronchoalveolar lavage fluid (BALF), lung histology, serum immunoglobulin (Ig), cytokine profiles of BALF and lung draining lymph nodes (LLNs), the expression of interleukin (IL)-25 and transforming growth factor (TGF)-β in mouse lung epithelial cell (MLE-12 cell), and dendritic cell (DC) differentiation. The intraperitoneal and intranasal administration of PON1 significantly decreased AHR, total inflammatory cells and eosinophils in BALF, eosinophilic airway inflammation, serum total, and OVA-specific IgE. PON1 treatment, which marked reduced IL-4, IL-5, and IL-13 in the BALF and LLN but significantly increased interferon-γ and TGF-β. Furthermore, PON1 treatment significantly decreased the expression of IL-25 and increased TGF-β in MLE-12 cells. The expressions of CD40, CD80, and CD86 in immature DCs were significantly increased by PON1 treatment. The administration of PON1 ameliorated allergic airway inflammation and improved AHR through the downregulation of IL-4, IL-5, and IL-13 and upregulation of TGF-β in asthmatic mice. Furthermore, PON1 treatment decreased Th2-mediated inflammation induced by <i>Aspergillus</i> protease antigen by decreasing IL-25 and increasing TGF-β.