Long noncoding RNA AVAN promotes antiviral innate immunity by interacting with TRIM25 and enhancing the transcription of FOXO3a

Chengcai Lai; Lihui Liu; Qinghua Liu; Sijie Cheng; Keyu Wang; Lingna Zhao; Min Xia; Cheng Wang; Hongjing Gu; Yueqiang Duan; Zhongpeng Zhao; Lili Zhang; Ziyang Liu; Jianjun Luo; Jianxun Song; Penghui Yang; Runsheng Chen; Xiliang Wang

The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/623132 doi: bioRxiv preprint that lung wet-to-dry ratio and viral titer in TG mice was significantly lower than that in WT 306 mice (Fig 7D, E) . Pathologic examination by HE attaining revealed that histopathlogic 307 alterations improved in TG mice ( Fig 7F) . Subsequently, we detected FOXO3a expression 308 levels and found that FOXO3a expression were undetectable in TG mice (data not shown), 309 likely due to low AVAN homology in humans and mice. Striking, we found that AVAN also 310 bind to rodent TRIM25 through RNA pull-down using TG mice tissue ( Fig 7G) and promote 311 type I IFN expression in vivo (Fig 7H) . Similarly, we constructed an AVAN-containing 312 AAV2/9 vector and a control vector, which were then delivered into 4-week-old C57L/B6 313 mice via intranasal (i.n.) administration. We found that AVAN was ectopically expressed in the 314 lung of AAV2/9-AVAN treated mice ( Fig S8A) . Strikingly, after IAV-BJ501 infection, the 315 groups pretreated with AAV2/9-AVAN exhibited significantly increased survival rates and 316 reduced body weight loss at 10 days post-infection compared with the control group ( Fig S8B, 317 C). Furthermore, lung edema, measured as the wet-to-dry ratio of whole lung, was 318 ameliorated (Fig S8D) , and improved lung histopathology was observed in infected mice 319 pretreated with AAV2/9-AVAN (Fig S8E, F) . Moreover, the virus titer from the lungs of 320 infected mice was also significantly reduced in AAV2/9-AVAN-treated mice compared with 321 that in control mice (Fig S8G, H) . In addition, AAV2/9-AVAN promote type I IFN expression 322 in vivo (Fig S8I) . Taken together, these observations indicate that expression of lncRNA AVAN The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/623132 doi: bioRxiv preprint association between TRIM25 and RIG-I and enhances RIG-I ubiquitylation, thereby 393 promoting IFN expression. It is worth noting that AVAN binds TRIM25 and facilitates IFN 394 expression in mice. In addition, we explored the impact of AVAN overexpression or 395 knockdown in IFN induction, chemo attraction of neutrophils or expression of cytokines and 396 chemokines (Fig 3) , speculated that lncRNA AVAN is critical in the IFN induction pathway. 1/4 volume of 5× loading dye. The mixtures were then heated at 95°C and stored at -80°C. 496 The samples were separated by SDS-PAGE and transferred onto nitrocellulose membranes. 497 The membranes were then blocked with 5% nonfat milk (BD) in 1× Tris-buffered saline and 498 0.1% Triton 100 for 1 h while shaking at room temperature. Next, the membranes were 499 incubated with primary antibodies and horseradish peroxidase-conjugated secondary 500 antibodies. Bands were visualized using the Kodak film exposure detection system. The film 501 was scanned, and the band intensity was analyzed using Quantity One software. 502 All rights reserved. No reuse allowed without permission.