DICER1 and pneumonia: Although the expression levels of Dicer, XPO5, SRSF3, and hnRNPA3 were lower in the tissues of old mice than in those of young mice, PJ34 rescued the N-induced downregulation of Dicer, XPO5, SRSF3, and hnRNPA3 and ameliorated N protein-induced pneumonia not only in young mice but also in old mice (Fig. 9g and Supplementary Fig. 9e).