Submitted to: Research in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2017
Publication Date: 5/13/2017
Citation: Truong, A.D., Rengaraj, D., Hong, Y., Hoang, C.T., Hong, Y.H., Lillehoj, H.S. 2017. Differentially expressed JAK-STAT signaling pathway genes and target microRNAs in the spleen of necrotic enteritis-afflicted chicken lines. Research in Veterinary Science. 115:235-243. Interpretive Summary: This study reports a genetic analysis of poultry genes which are important in the host response to necrotic enteritis (NE) infection using two different inbred lines of chickens that show different levels of disease susceptibility. NE is caused by a bacteria called Clostridium perfringens and represents a serious enteric disease of commercial poultry for the US. In this paper, ARS scientists collaborated with scientists in South Korea to identify host genes which are differentially affected by NE so better prevention strategies can be developed. Comprehensive genetic analysis of NE-infected chickens showed that one of the important host gene pathways which controls the immune response in NE is the JAK-STAT pathway. Comparative gene expression analysis of host immune genes in two genetically disparate chicken lines (6.3 and 7.2), demonstrated the differential expression of the JAK-STAT signaling pathway genes that are involved in cell differentiation and the progression of several diseases by regulating gene expression. These results provide new knowledge on host immune response to NE that will facilitate the development of new prevention strategies for NE.
Technical Abstract: The JAK signal transducer and STAT signaling pathway is an important regulator of cell proliferation, differentiation, survival, motility, apoptosis, immune response, and development. In this study, we used RNA-Sequencing, qRT-PCR, and bioinformatics tools to investigate the differential expression of JAK-STAT pathway genes, their interactions, and regulators in the spleen of two genetically disparate chicken lines (Marek's disease-resistant line 6.3 and MD-susceptible line 7.2) induced with necrotic enteritis disease. Using RNA-Seq analysis, we identified a total of 116 JAK-STAT pathway genes that were differentially expressed in the spleen of these chickens. All of the identified genes were analyzed through clustering, mapping to the KEGG chicken JAK-STAT pathway, and the Pathway Studio program. Of the 116 JAK-STAT pathway genes, 20 were further verified by qRT-PCR. According to the RNA-Seq results, several key genes, including STAT1'6, JAK1'3, TYK2, AKT1, AKT3, SOCS1'5, PIAS1, PIAS2, PIAS4, SHP1, SHP2, and PIK3, showed marked differential expression in the two lines, relative to their respective controls. Moreover, the RNA-Seq results of many key genes were highly correlated with the qRT-PCR results. Finally, we predicted 63 mature miRNAs that variably target JAK-STAT pathway genes and are differentially expressed in the spleen of chickens of both lines. To the best of our knowledge, this study is the first to analyze most of the genes, interactions, and regulators of the JAK-STAT pathway in the innate immune response to NE disease in chickens.