Porcine epidemic diarrhea virus (PEDV) has catastrophic impacts on the global pig industry. Although the fecal–oral route is generally accepted, an increased number of reports indicate that airborne transmission may contribute to PEDV outbreak. Here, we show that PEDV could cause typical diarrhea in piglets through a nasal spray. Firstly, PEDV can develop a transient nasal epithelium infection. Subsequently, PEDV-carrying dendritic cells (DCs) allow the virus to be transferred to CD3+ T cells via the virological synapse. Finally, virus-loaded CD3+ T cells reach the intestine through the blood circulation, leading to intestinal infection via cell-to-cell contact. Our study provides evidence for airborne transmission of a gastrointestinal infected coronavirus and illustrates the mechanism of its transport from the entry site to the pathogenic site.

Interleukin-11 (IL-11), a well-known anti-inflammatory factor, provides protection from intestinal epithelium damage caused by physical or chemical factors. However, little is known of the role of IL-11 during viral infections. In this study, IL-11 expression at mRNA and protein levels were found to be high in Vero cells and the jejunum of piglets during porcine epidemic diarrhea virus (PEDV) infection, while IL-11 expression was found to be positively correlated with the level of viral infection. Pretreatment with recombinant porcine IL-11 (pIL-11) was found to suppress PEDV replication in Vero E6 cells, while IL-11 knockdown promoted viral infection. Furthermore, pIL-11 was found to inhibit viral infection by preventing PEDV-mediated apoptosis of cells by activating the IL-11/STAT3 signaling pathway. Conversely, application of a STAT3 phosphorylation inhibitor significantly antagonized the anti-apoptosis function of pIL-11 and counteracted its inhibition of PEDV. Our data suggest that IL-11 is a newfound PEDV-inducible cytokine, and its production enhances the anti-apoptosis ability of epithelial cells against PEDV infection. The potential of IL-11 to be used as a novel therapeutic against devastating viral diarrhea in piglets deserves more attention and study.

Porcine epidemic diarrhea virus (PEDV) is emerging as a major threat to the global swine industry. Clinical PEDV infection is associated with severe intestinal lesions, resulting in absorptive dysfunction and high mortality rates in suckling piglets. The extracellular matrix (ECM) is an important component of intestinal tissue, providing a structural framework and conveying tissue-specific signals to nearby enterocytes. In this study, we investigated the extensive ECM remodeling observed in intestinal epithelial cells infected with PEDV and elucidated the associated activated ECM receptor-related pathways. Protein-protein interaction network analysis revealed two significantly differentially expressed genes (cluster of differentiation 44 [ CD44 ] and serpin family E member 1 [ SERPINE1 ]) associated with the ECM. At the transcriptional level, both genes exhibited significant positive correlation with the extent of PEDV replication. Similarly, the expression of CD44 and PAI-1 (encoded by SERPINE1 ) was also increased in the intestines of piglets during viral infection. Furthermore, CD44 exhibited antiviral activity by enhancing the expression of antiviral cytokines (e.g., interleukin [IL]-6, IL-18, IL-11, and antimicrobial peptide beta-defensin 1) by activating nuclear factor-κB signaling. Conversely, PAI-1 was found to promote the release of progeny virions during PEDV infection, despite a decreased intracellular viral load. Nevertheless, the underlying mechanisms are still unclear. Taken together, our results highlighted the biological roles of specific ECM-regulated genes, i.e., CD44 and SERPINE1 in suppressing and promoting PEDV infection, thereby providing a theoretical foundation for the role of the ECM in intestinal infections and identifying potential therapeutic targets for PEDV.