Novel analysis of the Harderian gland transcriptome response to Newcastle disease virus in two inbred chicken lines

Abstract

Behind each eye of the chicken resides a unique lymph tissue, the Harderian gland, for which RNA sequencing (RNA-seq) analysis is novel. We characterized the response of this tissue to Newcastle disease virus (NDV) in two inbred lines with different susceptibility to NDV across three time points. Three-week-old relatively resistant (Fayoumi) and relatively susceptible (Leghorn) birds were inoculated with a high-titered (107EID50) La Sota strain of NDV via an oculonasal route. At 2, 6, and 10 days post infection (dpi) Harderian glands were collected and analyzed via RNA-seq. The Fayoumi had significantly more detectable viral transcripts in the Harderian gland at 2 dpi than the Leghorn, but cleared the virus by 6 dpi. At all three time points, few genes were declared differentially expressed (DE) between the challenged and nonchallenged birds, except for the Leghorns at 6 dpi, and these DE genes were predicted to activate an adaptive immune response. Relative to the Leghorn, the Fayoumi was predicted to activate more immune pathways in both challenged and nonchallenged birds suggesting a more elevated immune system in the Fayoumis under homeostatic conditions. Overall, this study helped characterize the function of this important tissue and its response to NDV.

Novel Combined Tissue Transcriptome Analysis After Lentogenic Newcastle Disease Virus Challenge in Inbred Chicken Lines of Differential Resistance

“…Because the transcriptome is not stagnant, a more comprehensive physiological picture can be obtained by an integrative analysis of the transcriptomes of multiple tissues at multiple time points after a treatment. Previously, the trachea epithelial cells, lung, and Harderian gland of Fayoumis and Leghorns at 2, 6, and 10 days post-infection (dpi) with lentogenic NDV have been individually analyzed with RNA-seq (Deist et al, 2017a;Deist et al, 2017b;Deist et al, 2018). The three tissues had very distinct responses to NDV (Deist et al, 2017a;Deist et al, 2017b;Deist et al, 2018).…”

“…Previously, the trachea epithelial cells, lung, and Harderian gland of Fayoumis and Leghorns at 2, 6, and 10 days post-infection (dpi) with lentogenic NDV have been individually analyzed with RNA-seq (Deist et al, 2017a;Deist et al, 2017b;Deist et al, 2018). The three tissues had very distinct responses to NDV (Deist et al, 2017a;Deist et al, 2017b;Deist et al, 2018). Taking a systems biology approach and analyzing the three tissues together will provide a more comprehensive picture of how the whole animal responded to NDV.…”

Genetic responses of inbred chicken lines illustrate importance of eIF2 family and immune-related genes in resistance to Newcastle disease virus

“…In the current study, the observed time effect on the expression of IFNB may help to explain the different rates of viral clearance between lines, as the Fayoumi had lower viral load than the Leghorn at 6 dpi 19,20 . Recognition of viral RNA by TLR7 triggers signaling for cytokines with antiviral activity to be upregulated 29 .…”

“…www.nature.com/scientificreports www.nature.com/scientificreports/ (Ghs6 and Ghs13), have shown that the Major Histocompatibility Complex (MHC) can contribute to the genetic resistance against NDV 28 . Evaluation of the transcriptome of these two genetically distinct lines also suggests that NDV infection may cause upregulation of different genes in a line-dependent manner 19 . These results were also observed in the spleen, where few interferon stimulated genes were upregulated by NDV challenge 21 .…”

“…At 21 days of age, half of the chickens were inoculated with 200 µl of 10 7 EID 50 of La Sota NDV (NDV challenged group, n = 49) through nasal and ocular inoculation routes. The other chickens received 200 µl of phosphate-buffered saline (PBS) (nonchallenged group, n = 40) through same conditions, as described in [19][20][21] . The chickens from both lines and challenge statuses (NDV challenged or nonchallenged) were euthanized with sodium pentobarbital solution at 2 or 6 dpi.…”