title: The Adh adhesin domain is required for trimeric autotransporter Apa1-mediated Actinobacillus pleuropneumoniae adhesion, autoaggregation, biofilm formation and pathogenicity.
abstract: Actinobacillus pleuropneumoniae is a causative agent of porcine pleuropneumonia, which is a highly contagious endemic disease of pigs. Adhesion is a critical first step in the infection process. Trimeric autotransporter adhesions (TAAs) have been identified as novel virulence factors; however, little is known on their roles in A. pleuropneumoniae pathogenicity. Here, our data show that YadA-like head region (Adh) of Apa1 was the optimal adhesion functional domain via segment expression and adhesion assays in vitro. Additionally, Adh induced partial protection against A. pleuropneumoniae 5b L20 and serotypes 1, 3, and 5a in mice. The deletion of Adh gene significantly decreased autoaggregation, biofilm formation and adherence to host cells in vitro. Furthermore, with delaying of clinical symptoms, reducing production of pro-inflammatory cytokines and lessening the lung injury after infection, Adh deletion strain (5bϕAdh) significantly reduced the pathogenicity to piglets. To elucidate the mechanism of lung injury, the differentially expressed genes in the lung tissues of piglets infected with the 5b L20 or 5bϕAdh strains were investigated using microarray analysis and validated by qRT-PCR. Compared with the 5b L20 infected piglets, 495 genes were differentially expressed in 5bϕAdh infected lung tissue (221 upregulated and 274 downregulated). Especially, the antigen processing and presentation gene IFI30 was increased following infection with the 5bϕAdh strain. Thus, Adh may enhance pathogenicity by depressing host immune recognition. We conclude that the head domain of the A. pleuropneumoniae trimeric autotransporter Apa1 regulates autoagglutination, biofilm formation, adhesion to host cells and pathogenicity.
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China. Electronic address: wlei_007@163.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Wanhai
authors.initials: W
authors.lastname: Qin
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Shuxin
authors.initials: S
authors.lastname: Yang
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Ruidong
authors.initials: R
authors.lastname: Zhai
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Changjiang
authors.initials: C
authors.lastname: Sun
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Fengguang
authors.initials: F
authors.lastname: Pan
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Ji
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Jingmin
authors.initials: J
authors.lastname: Gu
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Feng
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Chongtao
authors.initials: C
authors.lastname: Du
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Han
authors.affiliation: Section of Paediatrics, Imperial College London, London, UK.
authors.forename: P R
authors.initials: PR
authors.lastname: Langford
authors.affiliation: College of Veterinary Medicine, Jilin University, Xi'an Road 5333, Changchun, PR China. Electronic address: leilc@jlu.edu.cn.
authors.forename: Liancheng
authors.initials: L
authors.lastname: Lei
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000472:pathogenicity* / Q000502:physiology*; D018829:Adhesins, Bacterial / Q000235:genetics*; D000818:Animals; D018441:Biofilms / Q000254:growth & development; D020869:Gene Expression Profiling / Q000662:veterinary; D008168:Lung / Q000378:metabolism; D051379:Mice; D046228:Microarray Analysis / Q000662:veterinary; D011001:Pleuropneumonia / Q000382:microbiology / Q000503:physiopathology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000503:physiopathology*; D000069320:Type V Secretion Systems / Q000502:physiology; D014774:Virulence / Q000502:physiology; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D000069320:Type V Secretion Systems; D037521:Virulence Factors
keywords: Actinobacillus pleuropneumoniae; Adhesin; Adhesion domain; Pathogenicity