title: The role of TGF-β signaling and apoptosis in innate and adaptive immunity in zebrafish: a systems biology approach.
abstract: BACKGROUND
  The immune system is a key biological system present in vertebrates. Exposure to pathogens elicits various defensive immune mechanisms that protect the host from potential threats and harmful substances derived from pathogens such as parasites, bacteria, and viruses. The complex immune system of humans and many other vertebrates can be divided into two major categories: the innate and the adaptive immune systems. At present, analysis of the complex interactions between the two subsystems that regulate host defense and inflammatory responses remains challenging.
  
  
  RESULTS
  Based on time-course microarray data following primary and secondary infection of zebrafish by Candida albicans, we constructed two intracellular protein-protein interaction (PPI) networks for primary and secondary responses of the host. 57 proteins and 341 PPIs were identified for primary infection while 90 proteins and 385 PPIs were identified for secondary infection. There were 20 proteins in common while 37 and 70 proteins specific to primary and secondary infection. By inspecting the hub proteins of each network and comparing significant changes in the number of linkages between the two PPI networks, we identified TGF-β signaling and apoptosis as two of the main functional modules involved in primary and secondary infection.
  
  
  CONCLUSIONS
  Our initial in silico analyses pave the way for further investigation into the interesting roles played by the TGF-β signaling pathway and apoptosis in innate and adaptive immunity in zebrafish. Such insights could lead to therapeutic advances and improved drug design in the continual battle against infectious diseases.
authors.forename: Che
authors.initials: C
authors.lastname: Lin
authors.forename: Chin-Nan
authors.initials: CN
authors.lastname: Lin
authors.forename: Yu-Chao
authors.initials: YC
authors.lastname: Wang
authors.forename: Fang-Yu
authors.initials: FY
authors.lastname: Liu
authors.forename: Yung-Jen
authors.initials: YJ
authors.lastname: Chuang
authors.forename: Chung-Yu
authors.initials: CY
authors.lastname: Lan
authors.forename: Wen-Ping
authors.initials: WP
authors.lastname: Hsieh
authors.forename: Bor-Sen
authors.initials: BS
authors.lastname: Chen
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D002176:Candida albicans / Q000502:physiology; D006801:Humans; D007113:Immunity, Innate; D042541:Intracellular Space / Q000378:metabolism; D025941:Protein Interaction Mapping; D015398:Signal Transduction / Q000276:immunology*; D049490:Systems Biology; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D015027:Zebrafish / Q000276:immunology* / Q000382:microbiology
chemical_list: D016212:Transforming Growth Factor beta