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Relative Contribution of P5 and Hap Surface Proteins to Nontypable Haemophilus influenzae Interplay with the Host Upper and Lower Airways.

Euba B, Moleres J, Viadas C, Ruiz de los Mozos I, Valle J, Bengoechea JA, Garmendia J - PLoS ONE (2015)

Bottom Line: Hap involvement in NTHi375-host interaction was shown to be limited, despite promoting bacterial cell adhesion when expressed in H. influenzae RdKW20.We also show that Hap does not contribute to bacterial biofilm growth, and that its absence partially restores the deficiency in lung infection observed for the ΔompP5 mutant.Altogether, this work frames the relative importance of the P5 and Hap surface proteins in NTHi virulence.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain.

ABSTRACT
Nontypable Haemophilus influenzae (NTHi) is a major cause of opportunistic respiratory tract disease, and initiates infection by colonizing the nasopharynx. Bacterial surface proteins play determining roles in the NTHi-airways interplay, but their specific and relative contribution to colonization and infection of the respiratory tract has not been addressed comprehensively. In this study, we focused on the ompP5 and hap genes, present in all H. influenzae genome sequenced isolates, and encoding the P5 and Hap surface proteins, respectively. We employed isogenic single and double mutants of the ompP5 and hap genes generated in the pathogenic strain NTHi375 to evaluate P5 and Hap contribution to biofilm growth under continuous flow, to NTHi adhesion, and invasion/phagocytosis on nasal, pharyngeal, bronchial, alveolar cultured epithelial cells and alveolar macrophages, and to NTHi murine pulmonary infection. We show that P5 is not required for bacterial biofilm growth, but it is involved in NTHi interplay with respiratory cells and in mouse lung infection. Mechanistically, P5NTHi375 is not a ligand for CEACAM1 or α5 integrin receptors. Hap involvement in NTHi375-host interaction was shown to be limited, despite promoting bacterial cell adhesion when expressed in H. influenzae RdKW20. We also show that Hap does not contribute to bacterial biofilm growth, and that its absence partially restores the deficiency in lung infection observed for the ΔompP5 mutant. Altogether, this work frames the relative importance of the P5 and Hap surface proteins in NTHi virulence.

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Related in: MedlinePlus

Interaction of NTHi375 mutants lacking the ompP5 and hap genes with alveolar macrophages.NTHi375, ΔompP5, Δhap and ΔompP5Δhap strains were used to assess adhesion to- (A) and phagocytosis by- (B) MH-S alveolar macrophages. Experiments were performed in triplicate in at least three independent occasions (n≥9).
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pone.0123154.g004: Interaction of NTHi375 mutants lacking the ompP5 and hap genes with alveolar macrophages.NTHi375, ΔompP5, Δhap and ΔompP5Δhap strains were used to assess adhesion to- (A) and phagocytosis by- (B) MH-S alveolar macrophages. Experiments were performed in triplicate in at least three independent occasions (n≥9).

Mentions: The lung contains alveolar macrophages which are both sentinels and the first line of defence against infection [42]. Clearance of NTHi from lungs depends on the efficiency of host phagocytes to recognise and destroy the pathogen, as we have previously described [36]. We next investigated the ability of MH-S alveolar macrophages to engulf NTHi375ΔompP5, Δhap and ΔompP5Δhap mutant strains. Adhesion of NTHi375ΔompP5 and ΔompP5Δhap to MH-S cells was lower than that displayed by the wild-type strain (p<0.005 and p<0.05, respectively). Differently, adhesion of NTHi375Δhap to MH-S cells was similar to the wild-type strain (Fig 4A). In agreement with adhesion data, phagocytosis of NTHi375ΔompP5 and ΔompP5Δhap by MH-S cells was significantly lower than that displayed by the wild-type strain (p<0.01 and p<0.005, respectively), and NTHi375Δhap mutant was engulfed by MH-S cells at the same level as the wild-type strain (Fig 4B). These results suggest a relevant role for P5 in NTHi recognition and engulfment by alveolar macrophages, together with a differential contribution of P5 and Hap to NTHi375 interface with this cell type.


Relative Contribution of P5 and Hap Surface Proteins to Nontypable Haemophilus influenzae Interplay with the Host Upper and Lower Airways.

Euba B, Moleres J, Viadas C, Ruiz de los Mozos I, Valle J, Bengoechea JA, Garmendia J - PLoS ONE (2015)

Interaction of NTHi375 mutants lacking the ompP5 and hap genes with alveolar macrophages.NTHi375, ΔompP5, Δhap and ΔompP5Δhap strains were used to assess adhesion to- (A) and phagocytosis by- (B) MH-S alveolar macrophages. Experiments were performed in triplicate in at least three independent occasions (n≥9).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403991&req=5

pone.0123154.g004: Interaction of NTHi375 mutants lacking the ompP5 and hap genes with alveolar macrophages.NTHi375, ΔompP5, Δhap and ΔompP5Δhap strains were used to assess adhesion to- (A) and phagocytosis by- (B) MH-S alveolar macrophages. Experiments were performed in triplicate in at least three independent occasions (n≥9).
Mentions: The lung contains alveolar macrophages which are both sentinels and the first line of defence against infection [42]. Clearance of NTHi from lungs depends on the efficiency of host phagocytes to recognise and destroy the pathogen, as we have previously described [36]. We next investigated the ability of MH-S alveolar macrophages to engulf NTHi375ΔompP5, Δhap and ΔompP5Δhap mutant strains. Adhesion of NTHi375ΔompP5 and ΔompP5Δhap to MH-S cells was lower than that displayed by the wild-type strain (p<0.005 and p<0.05, respectively). Differently, adhesion of NTHi375Δhap to MH-S cells was similar to the wild-type strain (Fig 4A). In agreement with adhesion data, phagocytosis of NTHi375ΔompP5 and ΔompP5Δhap by MH-S cells was significantly lower than that displayed by the wild-type strain (p<0.01 and p<0.005, respectively), and NTHi375Δhap mutant was engulfed by MH-S cells at the same level as the wild-type strain (Fig 4B). These results suggest a relevant role for P5 in NTHi recognition and engulfment by alveolar macrophages, together with a differential contribution of P5 and Hap to NTHi375 interface with this cell type.

Bottom Line: Hap involvement in NTHi375-host interaction was shown to be limited, despite promoting bacterial cell adhesion when expressed in H. influenzae RdKW20.We also show that Hap does not contribute to bacterial biofilm growth, and that its absence partially restores the deficiency in lung infection observed for the ΔompP5 mutant.Altogether, this work frames the relative importance of the P5 and Hap surface proteins in NTHi virulence.

View Article: PubMed Central - PubMed

Affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain.

ABSTRACT
Nontypable Haemophilus influenzae (NTHi) is a major cause of opportunistic respiratory tract disease, and initiates infection by colonizing the nasopharynx. Bacterial surface proteins play determining roles in the NTHi-airways interplay, but their specific and relative contribution to colonization and infection of the respiratory tract has not been addressed comprehensively. In this study, we focused on the ompP5 and hap genes, present in all H. influenzae genome sequenced isolates, and encoding the P5 and Hap surface proteins, respectively. We employed isogenic single and double mutants of the ompP5 and hap genes generated in the pathogenic strain NTHi375 to evaluate P5 and Hap contribution to biofilm growth under continuous flow, to NTHi adhesion, and invasion/phagocytosis on nasal, pharyngeal, bronchial, alveolar cultured epithelial cells and alveolar macrophages, and to NTHi murine pulmonary infection. We show that P5 is not required for bacterial biofilm growth, but it is involved in NTHi interplay with respiratory cells and in mouse lung infection. Mechanistically, P5NTHi375 is not a ligand for CEACAM1 or α5 integrin receptors. Hap involvement in NTHi375-host interaction was shown to be limited, despite promoting bacterial cell adhesion when expressed in H. influenzae RdKW20. We also show that Hap does not contribute to bacterial biofilm growth, and that its absence partially restores the deficiency in lung infection observed for the ΔompP5 mutant. Altogether, this work frames the relative importance of the P5 and Hap surface proteins in NTHi virulence.

Show MeSH
Related in: MedlinePlus