Deep sequencing of primary human lung epithelial cells challenged with H5N1 influenza virus reveals a proviral role for CEACAM1

Siying Ye; Chris Cowled; Cheng-Hon Yap; John Stambas

The functional consequences of CEACAM1 knockdown were then examined in ATII and A549 258 cells following H5N1 infection. IL-6, IFN-β, CXCL10, CCL5, and TNF production was analyzed in 259 H5N1-infected A549 and ATII cells using qRT-PCR. ATII (Fig. 5A ) and A549 cells ( The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/324723 doi: bioRxiv preprint modulation of reactive oxygen species (ROS) to reduce inflammation (5) and inhibition of NFκB and 278 mitogenic Raf/MEK/ERK kinase cascade activation to suppress viral replication (34, 35). These host 279 targeting strategies will offer an alternative to current interventions that are focused on targeting the 280 virus. In the present study, we analyzed human host gene expression profiles following HPAI H5N1 281 infection and treatment with the antioxidant apocynin. As expected, genes that were significantly 282 upregulated following H5N1 infection were involved in biological processes including cytokine 283 signaling, immunity and apoptosis. In addition, H5N1-upregulated genes were also involved in 284 regulation of protein phosphorylation, cellular metabolism and cell proliferation, which are thought to 285 be exploited by viruses for replication (36). Apocynin treatment had both anti-viral (Table S2 , S3, S4) 286 (6) and pro-viral impact (Fig. 2G) , which is not surprising as ROS are potent microbicidal agents, as 287 well as important immune signaling molecules at different concentrations (37). In our hands, apocynin 288 treatment reduced H5N1-induced inflammation, but unavoidably impacted the cellular defense 289 response, cytokine production and cytokine-mediated signaling. Importantly, critical antiviral responses 290