Supplementary Material for: MiR-21-5p modulates airway inflammation and epithelial-mesenchymal transition processes in a mouse model of CARAS

Introduction: Combined allergic rhinitis and asthma syndrome (CARAS) is a concurrent allergic symptom of diseases of allergic rhinitis and asthma. However, the mechanism of CARAS remains unclear. The study aimed to investigate the impact of microRNA-21 (miR-21) on CARAS via targeting Poly (ADP-ribose) polymerase-1 (PARP-1) and PI3K/AKT pathways.
Methods: The levels of miR-21-5p and PARP-1 in CARAS patients were detected by Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Enzyme-linked Immunosorbent Assay (ELISA). An ovalbumin (OVA)-sensitized mouse model of CARAS was established. And knock down of miR-21-5p was constructed by intranasally administering with miR-21-5p shRNA-encoding adeno-associated virus (AAV) vector. Airway resistance and airway inflammatory response were detected. ELISA was used to evaluate IL-4/IL-5/IL-13 levels in bronchoalveolar lavage fluid (BALF). Expression levels of E-cadherin, fibronectin, and α-SMA were determined using western blotting. The levels of PARP-1 and the activation of PI3K/AKT were assayed.
Results: Down-regulation of miR-21-5p relieved pathophysiological symptoms of asthma including airway hyperreactivity and inflammatory cell infiltration. Down-regulation of miR-21-5p significantly reduced the levels of IL4, IL-5, and IL-13 in BALF. Additionally, down-regulation of miR-21-5p inhibited the epithelial-mesenchymal transition (EMT) process in CARAS mice. Furthermore, miR-21-5p regulated PARP-1 and was involved in PI3K/AKT activation in CARAS mice.
Conclusion: Down-regulation of miR-21-5p ameliorated CARAS-associated lung injury by alleviating airway inflammation, inhibiting the EMT process and regulating PARP-1/PI3K/AKT in a mouse model of CARAS.