microRNA Expression Study of chicken CD3-28-4+ intraepithelial lymphocyte natural killer cells infected with very virulent Infectious Bursal Disease Virus

Infectious bursal disease is an acute immunosuppressive viral disease which significantly affect the economic in poultry industrial. Infectious bursal disease virus (IBDV) infection was known to destroy B lymphocytes, activate macrophage and T lymphocytes, but there are limited studies on the impact of IBDV infection on chicken intraepithelial Natural killer (IEL-NK) cells. The main objective of this study is to determine the innate immune response of chicken IEL-NK cells towards very virulent IBDV (vvIBDV) infection. Specific pathogen free (SPF) chickens were infected with vvIBDV for 0, 1 and 3 dpi. The IEL-NK cells were isolated and enriched from total IEL cells using the 28.4+ antibodies. The microRNA sequencing was conducted in MiSeq system and approximately 1.6 to 3.6 million single reads generated per sample. The differential expression analysis was performed on the miRNA-Seq data. there are 35 and 16 sRNAs were differentially expressed at 1 and 3 dpi, respectively. The SNORD101, gga-miR-222a and gga-miR-221-3p were up-regulated on Day 1 and 3 whereas gga-miR-30a-50, gga-miR-142-5p, gga-miR-32-5p and gga-miR-146b-5p were down-regulated on both days. gga-miR-217-5p and gga-miR-222b-5p with the highest fold change were involved in the regulation of tumor growth and apoptosis by targeting the MAPK signaling pathway. The vvIBDV replication was suppressed by overexpression of gga-miR-21 at 3 dpi. Some of the miRNAs were up-regulated with unknown reasons but the same findings were showed in other publications such as gga-miR-3538 and gga-miR-2954 which were up-regulated after being infected by other viruses, but the roles of these miRNA are not clear. The miRNA-Seq data for 3 groups of samples (uninfected chicken, chicken infected by vvIBDV for 1 day and chicken infected by vvIBDV for 3 days) in triplicate was generated using MiSeq