TY - JOUR
T1 - RNA-seq analysis of mucosal immune responses reveals signatures of intestinal barrier disruption and pathogen entry following Edwardsiella ictaluri infection in channel catfish, Ictalurus punctatus
AU - Li, Chao
AU - Zhang, Yu
AU - Wang, Ruijia
AU - Lu, Jianguo
AU - Nandi, Samiran
AU - Mohanty, Sriprakash
AU - Terhune, Jeffery
AU - Liu, Zhanjiang
AU - Peatman, Eric
N1 - Funding Information:
This project was supported in part by an Alabama Agriculture Experiment Station Hatch award to E. Peatman under project ALA016-1-09035. Additional support for S. Nandi and S. Mohanty was provided by the Indian Council of Agricultural Research. C. Li was supported by a scholarship from the China Scholarship Council (CSC).
PY - 2012/5
Y1 - 2012/5
N2 - The mucosal surfaces of fish (gill, skin, gastrointestinal tract) are important sites of bacterial exposure and host defense mechanisms. In mammalian systems, the intestinal epithelium is well characterized as both a selectively permeable barrier regulated by junctional proteins and as a primary site of infection for a number of enteric pathogens including viruses, bacteria, and parasites. The causative bacterium of enteric septicemia of catfish, Edwardsiella ictaluri, is believed to gain entry through the intestinal epithelium, with previous research using a rat intestinal epithelial cell line (IEC-6) indicating actin polymerization and receptor-mediated endocytosis as potential mechanisms of uptake. Here, we utilized high-throughput RNA-seq to characterize the role of the intestinal epithelial barrier following E. ictaluri challenge. A total of 197.6 million reads were obtained and assembled into 176,481 contigs with an average length of 893.7 bp and N50 of 1676 bp. The assembled contigs contained 14,457 known unigenes, including 2719 genes not previously identified in other catfish transcriptome studies. Comparison of digital gene expression between challenged and control samples revealed 1633 differentially expressed genes at 3 h, 24 h, and 3 day following exposure. Gene pathway analysis of the differentially expressed gene set indicated the centrality of actin cytoskeletal polymerization/remodelling and junctional regulation in pathogen entry and subsequent inflammatory responses. The expression patterns of fifteen differentially expressed genes related to intestinal epithelial barrier dysfunction were validated by quantitative real-time RT-PCR (average correlation coeff. 0.92, p < 0.001). Our results set a foundation for future studies comparing mechanisms of pathogen entry and mucosal immunity across several important catfish pathogens including E. ictaluri, Edwardsiellatarda, Flavobacterium columnare, and virulent atypical Aeromonas hydrophila. Understanding of molecular mechanisms of pathogen entry during infection will provide insight into strategies for selection of resistant catfish brood stocks against various diseases.
AB - The mucosal surfaces of fish (gill, skin, gastrointestinal tract) are important sites of bacterial exposure and host defense mechanisms. In mammalian systems, the intestinal epithelium is well characterized as both a selectively permeable barrier regulated by junctional proteins and as a primary site of infection for a number of enteric pathogens including viruses, bacteria, and parasites. The causative bacterium of enteric septicemia of catfish, Edwardsiella ictaluri, is believed to gain entry through the intestinal epithelium, with previous research using a rat intestinal epithelial cell line (IEC-6) indicating actin polymerization and receptor-mediated endocytosis as potential mechanisms of uptake. Here, we utilized high-throughput RNA-seq to characterize the role of the intestinal epithelial barrier following E. ictaluri challenge. A total of 197.6 million reads were obtained and assembled into 176,481 contigs with an average length of 893.7 bp and N50 of 1676 bp. The assembled contigs contained 14,457 known unigenes, including 2719 genes not previously identified in other catfish transcriptome studies. Comparison of digital gene expression between challenged and control samples revealed 1633 differentially expressed genes at 3 h, 24 h, and 3 day following exposure. Gene pathway analysis of the differentially expressed gene set indicated the centrality of actin cytoskeletal polymerization/remodelling and junctional regulation in pathogen entry and subsequent inflammatory responses. The expression patterns of fifteen differentially expressed genes related to intestinal epithelial barrier dysfunction were validated by quantitative real-time RT-PCR (average correlation coeff. 0.92, p < 0.001). Our results set a foundation for future studies comparing mechanisms of pathogen entry and mucosal immunity across several important catfish pathogens including E. ictaluri, Edwardsiellatarda, Flavobacterium columnare, and virulent atypical Aeromonas hydrophila. Understanding of molecular mechanisms of pathogen entry during infection will provide insight into strategies for selection of resistant catfish brood stocks against various diseases.
KW - Channel catfish
KW - Fish
KW - Immune response
KW - Intestine
KW - RNA-seq
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UR - http://www.scopus.com/inward/citedby.url?scp=84862786822&partnerID=8YFLogxK
U2 - 10.1016/j.fsi.2012.02.004
DO - 10.1016/j.fsi.2012.02.004
M3 - Article
C2 - 22366064
AN - SCOPUS:84862786822
SN - 1050-4648
VL - 32
SP - 816
EP - 827
JO - Fish and Shellfish Immunology
JF - Fish and Shellfish Immunology
IS - 5
ER -