Functional role of ompF and ompC porins in pathogenesis of avian pathogenic Escherichia coli.
Avian pathogenic Escherichia coli is an important pathogen causes systemic infections in avian species and large economic losses in poultry industry worldwide. The functional role of porins during the infection and their mechanisms of interaction with host tissues for adhesion to and invasion are poorly understood. However, whether porins play a role in infection remains unclear. In this study we evaluated the potential of ompF and ompC outer membrane porins in the pathogenesis of avian pathogenic E. coli (APEC) strain TW-XM. The ompF and ompC were deleted to generate a series of mutants. We found that, ΔompF and ΔompC reduced significantly the adherence by 41.3% and 46.1% and invasion capabilities of APEC to mouse brain microvascular endothelial cell (BMEC) bEnd.3 cells in vitro by 51.9% and 49.7% respectively, compared with the wild strain TW-XM. In vivo experiment based on the measurement of the LD50have also shown that, ΔompF and ΔompC reduced the bacterial virulence by 9.8-fold, 12.3-fold in ducklings and 9-fold, 10.2-fold in mouse models. Animal infection experiments further revealed that, loss of ompF and ompC reduced TW-XM colonization and invasion capacity in brains, lungs and blood compared to wild-type strain TW-XM (P > 0.01). These virulence-related phenotypes were partially recoverable by genetic complementation. The results of the quantitative real-time reverse transcription-PCR (qRT-PCR) indicated that, the loss of ompF and ompC significantly decreased the expression levels of ompA, fimC and iBeA genes in the mutant strains, compared to wild-type strainTW-XM (P < 0.01). Collectively, our data demonstrate that inactivation of these two porins decreased adhesion, invasion, colonization, proliferation capacities, possibly by reduced expression levels of ompA, fimC and iBeA, which may indicate the involvement of ompF and ompC in APEC pathogenesis.
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; College of Veterinary Sciences, University of Nyala, Nyala, Sudan.
Hassan M A
HMA
Hejair
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China.
Yinchu
Y
Zhu
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China.
Jiale
J
Ma
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China.
Yue
Y
Zhang
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China.
Zihao
Z
Pan
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China.
Wei
W
Zhang
College of Veterinary Medicine, Nanjing Agricultural University, Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China. Electronic address: yaohch@njau.edu.cn.
Huochun
H
Yao
D000818:Animals; D000907:Antibodies, Bacterial; D001422:Bacterial Adhesion / Q000235:genetics / Q000502:physiology; D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D001717:Birds; D001921:Brain / Q000382:microbiology; D002460:Cell Line / Q000382:microbiology; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000235:genetics; D004195:Disease Models, Animal; D004372:Ducks / Q000382:microbiology; D042783:Endothelial Cells / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D036781:Fimbriae Proteins / Q000096:biosynthesis / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007928:Lethal Dose 50; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D018272:Porins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011201:Poultry Diseases / Q000382:microbiology*; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D011994:Recombinant Proteins / Q000235:genetics; D017421:Sequence Analysis; D017384:Sequence Deletion; D016019:Survival Analysis; D014774:Virulence / Q000235:genetics* / Q000502:physiology*
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; C096350:CusC protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C113724:OmpC protein; C109237:OmpF protein; D018272:Porins; D011994:Recombinant Proteins; C489721:fimC protein, E coli; D036781:Fimbriae Proteins; C078167:OMPA outer membrane proteins
APEC; Adhesion; Invasion; Pathogenesis; ompC; ompF