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Li L, Chen Z, Bei W, Su Z, Huang Q, Zhang L, Chen H, Zhou R. Catecholamines promote Actinobacillus pleuropneumoniae growth by regulating iron metabolism. PLoS One 2015; 10:e0121887. [PMID: 25849041 PMCID: PMC4388731 DOI: 10.1371/journal.pone.0121887] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/04/2015] [Indexed: 01/18/2023] Open
Abstract
Catecholamines are host stress hormones that can induce the growth of many bacteria by facilitating iron utilization and/or regulate the expression of virulence genes through specific hormone receptors. Whether these two responsive pathways are interconnected is unknown. In our previous study, it was found that catecholamines can regulate the expression of a great number of genes of Actinobacillus pleuropneumoniae, an important swine respiratory pathogen. However, bacterial growth was not affected by catecholamines in rich medium. In this study, it was discovered that catecholamines affected A. pleuropneumoniae growth in chemically defined medium (CDM). We found that serum inhibited A. pleuropneumoniae growth in CDM, while epinephrine, norepinephrine and dopamine promoted A. pleuropneumoniae growth in the CDM containing serum. The known bacterial hormone receptor QseC didn’t play roles in this process. Ion-supplementation and transcriptome analysis indicated that serum addition resulted in iron-restricted conditions which were alleviated by the addition of catecholamines. Transferrin, one of the components in serum, inhibited the growth of A. pleuropneumoniae in CDM, an effect reversed by addition of catecholamines in a TonB2-dependent manner. Our data demonstrate that catecholamines promote A. pleuropneumoniae growth by regulating iron-acquisition and metabolism, which is independent of the adrenergic receptor QseC.
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Affiliation(s)
- Lu Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- * E-mail: (LL); (RZ)
| | - Zhaohui Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Weicheng Bei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhipeng Su
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Qi Huang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Liang Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Rui Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- * E-mail: (LL); (RZ)
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Luna-Castro S, Aguilar-Romero F, Samaniego-Barrón L, Godínez-Vargas D, de la Garza M. Effect of bovine apo-lactoferrin on the growth and virulence of Actinobacillus pleuropneumoniae. Biometals 2014; 27:891-903. [DOI: 10.1007/s10534-014-9752-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 05/15/2014] [Indexed: 01/01/2023]
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Bahrami F, Niven DF. Iron acquisition by Actinobacillus suis: Identification and characterization of a single-component haemoglobin receptor and encoding gene. Microb Pathog 2005; 39:45-51. [PMID: 15899574 DOI: 10.1016/j.micpath.2005.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Revised: 03/07/2005] [Accepted: 03/14/2005] [Indexed: 11/21/2022]
Abstract
Actinobacillus suis is an important swine pathogen. As with other pathogens, the ability of A. suis to acquire iron within the host is crucial for virulence. Here, we investigated the ability of seven strains of A. suis to acquire iron from haemoglobins. In growth assays, all strains could use porcine, bovine and human haemoglobins as iron sources for growth. Using solid phase binding assays, membranes derived from all strains, grown under iron-restricted conditions, were shown to bind all three haemoglobins. Competition binding assays indicated that these haemoglobins were bound by the same receptor and an affinity procedure allowed the isolation and identification of an iron-repressible, haemoglobin-binding polypeptide (approximately 105 kDa) from all strains. Nucleotide sequence analyses revealed that A. suis possesses a gene (hgbA) that encodes a homologue of the Actinobacillus pleuropneumoniae haemoglobin-binding protein, HgbA. hgbA, encoding a mature protein of 105 kDa, was shown to be preceded by a hugZ homologue; putative promoter sequences and a putative Fur box were located upstream of hugZ and RT-PCR revealed that hugZ and hgbA are co-transcribed and iron-repressible. It is concluded that the acquisition of haemoglobin-bound iron by A. suis involves a single-component receptor that is up-regulated in response to iron restriction.
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Affiliation(s)
- Fariborz Bahrami
- Microbiology Unit, Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Que., Canada H9X 3V9
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Pawelek PD, Coulton JW. Hemoglobin-binding protein HgbA in the outer membrane of Actinobacillus pleuropneumoniae: homology modelling reveals regions of potential interactions with hemoglobin and heme. J Mol Graph Model 2005; 23:211-21. [PMID: 15530817 DOI: 10.1016/j.jmgm.2004.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Revised: 06/25/2004] [Accepted: 06/25/2004] [Indexed: 11/21/2022]
Abstract
Analyses of the primary sequence of hemoglobin-binding protein HgbA from Actinobacillus pleuropneumoniae by comparative modelling and by a Hidden Markov Model identified its topological similarities to bacterial outer membrane receptors BtuB, FepA, FhuA, and FecA of Escherichia coli. The HgbA model has a globular N-terminal cork domain contained within a 22-stranded beta barrel domain, its folds being similar to the structures of outer membrane receptors that have been solved by X-ray crystallography. The barrel domain of the HgbA model superimposes onto the barrel domains of the four outer membrane receptors with rmsd values less than 1.0 A. This feature is consistent with a phylogenetic tree which indicated clustering of polypeptide sequences for three barrel domains. Furthermore, the HgbA model shares the highest structural similarity to BtuB, with the modelled HgbA barrel having approximately the same elliptical cross-section and height as that of BtuB. Extracellular loop regions of HgbA are predicted to be more extended than those of the E. coli outer membrane receptors, potentially facilitating a protein-protein interface with hemoglobin. Fold recognition modelling of the HgbA loop regions showed that 10 out of 11 predicted loops are highly homologous to known structures of protein loops that contribute to heme/iron or protein-protein interactions. Strikingly, HgbA loop 2 has structural homology to a loop in bovine endothelial nitric acid oxidase that is proximal to a heme-binding site; and HgbA loop 7 contains a histidine residue conserved in a motif that is involved in heme/hemoglobin interactions. These findings implicate HgbA loops 2 and 7 in recognition and binding of hemoglobin or the heme ligand.
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Affiliation(s)
- Peter D Pawelek
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, QC, Canada H3A 2B4
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Srikumar R, Mikael LG, Pawelek PD, Khamessan A, Gibbs BF, Jacques M, Coulton JW. Molecular cloning of haemoglobin-binding protein HgbA in the outer membrane of Actinobacillus pleuropneumoniae. Microbiology (Reading) 2004; 150:1723-1734. [PMID: 15184559 DOI: 10.1099/mic.0.27046-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
From the porcine pathogenActinobacillus pleuropneumoniaecultivated in iron-deficient or haem-deficient media, haemoglobin (Hb)-agarose affinity purification was exploited to isolate an outer-membrane protein of ∼105 kDa, designated HgbA. Internal peptide sequences of purified HgbA were used to design oligonucleotide primers for PCR amplification, yielding amplicons that showed partial sequences with homology tohgbAofPasteurella multocida. Upon screening two genomic libraries ofA. pleuropneumoniaeserotype 1 strain 4074, positive clones were assembled into an ORF of 2838 bp. HgbA (946 aa) includes a signal peptide of 23 aa and the deduced HgbA sequence (104 890 Da) also demonstrated a possible Ton box. The promoter region ofhgbAfromA. pleuropneumoniaeserotype 1 showed consensus for −35 and −10 sequences and a putative Fur-binding site. RT-PCR confirmed thathgbAofA. pleuropneumoniaeis upregulated in response to diminished levels of iron in the culture medium. While an internally deletedhgbAmutant was unable to use pig Hb as sole source of iron for growth, flow cytometry confirmed its Hb binding; the internally deleted sequences may not be required for Hb binding, but appear necessary for the iron supply from Hb. HgbA is required for growth ofA. pleuropneumoniaein the presence of Hb as sole iron source.
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Affiliation(s)
- Ramakrishnan Srikumar
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, QC, Canada H3A 2B4
| | - Leonie G Mikael
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada J2S 7C6
| | - Peter D Pawelek
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, QC, Canada H3A 2B4
| | - Ali Khamessan
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, QC, Canada H3A 2B4
| | | | - Mario Jacques
- Groupe de Recherche sur les Maladies Infectieuses du Porc, Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, Canada J2S 7C6
| | - James W Coulton
- Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, QC, Canada H3A 2B4
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Bossé JT, Janson H, Sheehan BJ, Beddek AJ, Rycroft AN, Kroll JS, Langford PR. Actinobacillus pleuropneumoniae: pathobiology and pathogenesis of infection. Microbes Infect 2002; 4:225-35. [PMID: 11880056 DOI: 10.1016/s1286-4579(01)01534-9] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Actinobacillus pleuropneumoniae causes porcine pleuropneumonia, a highly contagious disease for which there is no effective vaccine. This review considers how adhesins, iron-acquisition factors, capsule and lipopolysaccharide, RTX cytotoxins and other potential future vaccine components contribute to colonisation, to avoidance of host clearance mechanisms and to damage of host tissues.
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Affiliation(s)
- Janine T Bossé
- Molecular Infectious Diseases Group, Department of Paediatrics, Faculty of Medicine, Imperial College, St. Mary's Campus, W2 1PG, London, UK.
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Paradis SE, Dubreuil D, Jacques M. Examination of surface polysaccharides of Actinobacillus pleuropneumoniae serotype 1 grown under iron-restricted conditions. FEMS Microbiol Lett 1996; 137:201-6. [PMID: 8998986 DOI: 10.1111/j.1574-6968.1996.tb08106.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We investigated the expression of important Actinobacillus pleuropneumoniae surface polysaccharides, namely, capsular polysaccharides (CPS) and lipopolysaccharides (LPS), after growth under iron-restricted conditions. Iron restriction did not seem to affect the production of CPS, as determined by labelling with a monoclonal antibody (mAb) against the serotype 1 K-antigen and flow cytometry analysis, and also as determined by electron microscopy. SDS-PAGE revealed that the LPS profiles of these cells were also unaffected by iron restriction. Using flow cytometry analysis, however, we observed that binding of mAb against serotype 1 O-antigen was altered in cells of A. pleuropneumoniae serotype 1 reference strain (4074) grown under iron-restricted conditions. This strain exhibited two subpopulations with distinct patterns of reactivity with the mAb against the O-antigen. When strain 4074 was grown under iron-restricted conditions, a shift from one cell subpopulation (moderately fluorescent) to another cell subpopulation (highly fluorescent, thus binding more antibodies) was observed. Our results indicate that growth of A. pleuropneumoniae serotype 1 under iron-restricted conditions did not seem to affect CPS production, but might alter, at least for the reference strain, the expression of LPS.
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Affiliation(s)
- S E Paradis
- Département de pathologie et microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada
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