scholarly journals Expression of the Oligopeptide Permease Operon of Moraxella catarrhalis Is Regulated by Temperature and Nutrient Availability

2015 ◽  
Vol 83 (9) ◽  
pp. 3497-3505 ◽  
Author(s):  
Megan M. Jones ◽  
Timothy F. Murphy
Keyword(s):  
Virulence Factor ◽  
Nutrient Availability ◽  
Moraxella Catarrhalis ◽  
Regulation Of Gene Expression ◽  
Vaccine Antigen ◽  
Chronic Obstructive ◽  
Gene Transcript ◽  
Content Type ◽  
Oligopeptide Permease ◽  
Nutritional Virulence

Moraxella catarrhaliscauses otitis media in children and exacerbations of chronic obstructive pulmonary disease in adults. Together, these two conditions contribute to enormous morbidity and mortality worldwide. The oligopeptide permease (opp) ABC transport system is a nutritional virulence factor important for the utilization of peptides. The substrate binding protein OppA, which binds peptides for uptake, is a potential vaccine antigen, but little was known about the regulation of gene expression. The fiveoppgenesoppB,oppC,oppD,oppF, andoppAare in the same open reading frame. Sequence analysis predicted two promoters, one located upstream ofoppBand one within the intergenic region betweenoppFandoppA. We have characterized the gene cluster as an operon with two functional promoters and show that cold shock at 26°C for ≤0.5 h and the presence of a peptide substrate increase gene transcript levels. Additionally, the putative promoter upstream ofoppAcontributes to the transcription ofoppAbut is not influenced by the same environmental cues as the promoter upstream ofoppB. We conclude that temperature and nutrient availability contribute to the regulation of the Opp system, which is an important nutritional virulence factor inM. catarrhalis.

scholarly journals Mapping Protective Regions on a Three-Dimensional Model of theMoraxella catarrhalisVaccine Antigen Oligopeptide Permease A

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Antonia C. Perez ◽  
Antoinette Johnson ◽  
Ziqiang Chen ◽  
Gregory E. Wilding ◽  
Michael G. Malkowski ◽  
...  
Keyword(s):  
Protective Antigen ◽  
Financial Burden ◽  
Three Dimensional ◽  
Immune Serum ◽  
Vaccine Antigen ◽  
Chronic Obstructive ◽  
High Avidity ◽  
Three Dimensional Model ◽  
Content Type ◽  
Oligopeptide Permease

ABSTRACTA vaccine againstMoraxella catarrhaliswould reduce tremendous morbidity, mortality, and financial burden by preventing otitis media in children and exacerbations of chronic obstructive pulmonary disease (COPD) in adults. Oligopeptide permease A (OppA) is a candidate vaccine antigen that is (i) a nutritional virulence factor expressed on the bacterial cell surface during infection, (ii) widely conserved among strains, (iii) highly immunogenic, and (iv) a protective antigen based on its capacity to induce protective responses in immunized animals. In the present study, we show that the antibodies to OppA following vaccination mediate accelerated clearance in animals after pulmonary challenge. To identify regions of OppA that bind protective antibodies, truncated constructs of OppA were engineered and studied to map regions of OppA with surface-accessible epitopes that bind high-avidity antibodies following vaccination. Protective epitopes were located in the N and C termini of the protein. Immunization of mice with constructs corresponding to these regions (T5 and T8) induced protective responses. Studies of overlapping peptide libraries of constructs T5 and T8 with OppA immune serum identified two discrete regions on each construct. These potentially protective regions were mapped on a three-dimensional computational model of OppA, where regions with solvent-accessible amino acids were identified as three potentially protective epitopes. In all, these studies revealed two regions with three specific epitopes in OppA that induce potentially protective antibody responses following vaccination. Detection of antibodies to these regions could serve to guide vaccine formulation and as a diagnostic tool for monitoring development of protective responses during clinical trials.

scholarly journals Substrate Binding Protein SBP2 of a Putative ABC Transporter as a Novel Vaccine Antigen of Moraxella catarrhalis

2014 ◽  
Vol 82 (8) ◽  
pp. 3503-3512 ◽  
Author(s):  
Taketo Otsuka ◽  
Charmaine Kirkham ◽  
Antoinette Johnson ◽  
Megan M. Jones ◽  
Timothy F. Murphy
Keyword(s):  
Otitis Media ◽  
Moraxella Catarrhalis ◽  
Binding Protein ◽  
Substrate Binding ◽  
Vaccine Antigen ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Chronic Obstructive ◽  
Content Type ◽  
Substrate Binding Protein

ABSTRACTMoraxella catarrhalisis a common respiratory tract pathogen that causes otitis media in children and infections in adults with chronic obstructive pulmonary disease. Since the introduction of the pneumococcal conjugate vaccines with/without protein D of nontypeableHaemophilus influenzae,M. catarrhalishas become a high-priority pathogen in otitis media. For the development of antibacterial vaccines and therapies, substrate binding proteins of ATP-binding cassette transporters are important targets. In this study, we identified and characterized a substrate binding protein, SBP2, ofM. catarrhalis. Among 30 clinical isolates tested, thesbp2gene sequence was highly conserved. In 2 different analyses (whole-cell enzyme-linked immunosorbent assay and flow cytometry), polyclonal antibodies raised to recombinant SBP2 demonstrated that SBP2 expresses epitopes on the bacterial surface of the wild type but not thesbp2mutant. Mice immunized with recombinant SBP2 showed significantly enhanced clearance ofM. catarrhalisfrom the lung compared to that in the control group at both 25-μg and 50-μg doses (P< 0.001). We conclude that SBP2 is a novel, attractive candidate as a vaccine antigen againstM. catarrhalis.

scholarly journals A Cation-Binding Surface Protein as a Vaccine Antigen To Prevent Moraxella catarrhalis Otitis Media and Infections in Chronic Obstructive Pulmonary Disease

2017 ◽  
Vol 24 (9) ◽  
Author(s):  
Timothy F. Murphy ◽  
Aimee L. Brauer ◽  
Antoinette Johnson ◽  
Gregory E. Wilding ◽  
Mary Koszelak-Rosenblum ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Respiratory Tract ◽  
Pulmonary Disease ◽  
Otitis Media ◽  
Moraxella Catarrhalis ◽  
Vaccine Antigen ◽  
Chronic Obstructive ◽  
Human Respiratory Tract ◽  
Obstructive Pulmonary Disease ◽  
Content Type

ABSTRACT Moraxella catarrhalis is an exclusively human respiratory tract pathogen that is a common cause of otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease. A vaccine to prevent these infections would have a major impact on reducing the substantial global morbidity and mortality in these populations. Through a genome mining approach, we identified AfeA, an ∼32-kDa substrate binding protein of an ABC transport system, as an excellent candidate vaccine antigen. Recombinant AfeA was expressed and purified and binds ferric, ferrous, manganese, and zinc ions, as demonstrated by thermal shift assays. It is a highly conserved protein that is present in all strains of M. catarrhalis. Immunization with recombinant purified AfeA induces high-titer antibodies that recognize the native M. catarrhalis protein. AfeA expresses abundant epitopes on the bacterial surface and induces protective responses in the mouse pulmonary clearance model following aerosol challenge with M. catarrhalis. Finally, AfeA is expressed during human respiratory tract infection of adults with chronic obstructive pulmonary disease (COPD). Based on these observations, AfeA is an excellent vaccine antigen to be included in a vaccine to prevent infections caused by M. catarrhalis.

scholarly journals Moraxella catarrhalis Binds Plasminogen To Evade Host Innate Immunity

2015 ◽  
Vol 83 (9) ◽  
pp. 3458-3469 ◽  
Author(s):  
Birendra Singh ◽  
Tamim Al-Jubair ◽  
Chandrashekar Voraganti ◽  
Tobias Andersson ◽  
Oindrilla Mukherjee ◽  
...  
Keyword(s):  
Moraxella Catarrhalis ◽  
Bacterial Species ◽  
Factor H ◽  
Full Length ◽  
Respiratory Pathogen ◽  
Affinity Constant ◽  
Chronic Obstructive ◽  
Specific Substrate ◽  
Bacterial Killing ◽  
Content Type

Several bacterial species recruit the complement regulators C4b-binding protein, factor H, and vitronectin, resulting in resistance against the bactericidal activity of human serum. It was recently demonstrated that bacteria also bind plasminogen, which is converted to plasmin that degrades C3b and C5. In this study, we found that a series of clinical isolates (n= 58) of the respiratory pathogenMoraxella catarrhalis, which is commonly isolated from preschool children and adults with chronic obstructive pulmonary disease (COPD), significantly binds human plasminogen. Ubiquitous surface protein A2 (UspA2) and hybrid UspA2 (UspA2H) were identified as the plasminogen-binding factors in the outer membrane proteome ofMoraxella. Furthermore, expression of a series of truncated recombinant UspA2 and UspA2H proteins followed by a detailed analysis of protein-protein interactions suggested that the N-terminal head domains bound to the kringle domains of plasminogen. The binding affinity constant (KD) values of full-length UspA230–539(amino acids 30 to 539 of UspA2) and full-length UspA2H50–720for immobilized plasminogen were 4.8 × 10−8M and 3.13 × 10−8M, respectively, as measured by biolayer interferometry. Plasminogen bound to intactM. catarrhalisor to recombinant UspA2/UspA2H was readily accessible for a urokinase plasminogen activator that converted the zymogen into active plasmin, as verified by the specific substrate S-2251 and a degradation assay with fibrinogen. Importantly, plasmin bound at the bacterial surface also degraded C3b and C5, which consequently may contribute to reduced bacterial killing. Our findings suggest that binding of plasminogen toM. catarrhalismay lead to increased virulence and, hence, more efficient colonization of the host.

scholarly journals Proteome of a Moraxella catarrhalis Strain under Iron-Restricted Conditions

2020 ◽  
Vol 9 (12) ◽  
Author(s):  
Luke V. Blakeway ◽  
Aimee Tan ◽  
Ian R. Peak ◽  
John M. Atack ◽  
Kate L. Seib
Keyword(s):  
Mass Spectrometry ◽  
Chronic Obstructive Pulmonary Disease ◽  
Differential Expression ◽  
Pulmonary Disease ◽  
Moraxella Catarrhalis ◽  
Chronic Obstructive ◽  
Iron Starvation ◽  
Data Set ◽  
Obstructive Pulmonary Disease ◽  
Content Type

Moraxella catarrhalis is a leading cause of otitis media and exacerbations of chronic obstructive pulmonary disease; however, its response to iron starvation during infection is not completely understood. Here, we announce a sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) data set describing the differential expression of the M. catarrhalis CCRI-195ME proteome under iron-restricted versus iron-replete conditions.

scholarly journals Complete Genome Sequence of Moraxella catarrhalis Strain CCRI-195ME, Isolated from the Middle Ear

2017 ◽  
Vol 5 (21) ◽  
Author(s):  
Aimee Tan ◽  
Luke V. Blakeway ◽  
Lauren O. Bakaletz ◽  
Matthew Boitano ◽  
Tyson A. Clark ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Moraxella Catarrhalis ◽  
Complete Genome ◽  
Bacterial Pathogen ◽  
Chronic Obstructive ◽  
Phase Variable ◽  
Obstructive Pulmonary Disease ◽  
Content Type ◽  
Epigenetic Regulator

ABSTRACT Moraxella catarrhalis is an important bacterial pathogen that causes otitis media and exacerbations of chronic obstructive pulmonary disease. Here, we report the complete genome sequence of M. catarrhalis strain CCRI-195ME, which contains the phase-variable epigenetic regulator ModM3.

scholarly journals Transcriptome RNA Sequencing Data Set of Gene Expression in Moraxella catarrhalis On- and Off-Phase Variants of the Type III DNA Methyltransferase ModM3

2020 ◽  
Vol 9 (14) ◽  
Author(s):  
Luke V. Blakeway ◽  
Aimee Tan ◽  
Ian R. Peak ◽  
John M. Atack ◽  
Kate L. Seib
Keyword(s):  
Gene Expression ◽  
Rna Sequencing ◽  
Moraxella Catarrhalis ◽  
Dna Methyltransferase ◽  
Global Gene Expression ◽  
Chronic Obstructive ◽  
Sequencing Data ◽  
Data Set ◽  
Obstructive Pulmonary Disease ◽  
Content Type

Moraxella catarrhalis is a leading bacterial cause of otitis media and exacerbations of chronic obstructive pulmonary disease. Here, we announce a transcriptome RNA sequencing data set detailing global gene expression in two M. catarrhalis CCRI-195ME variants with expression of the DNA methyltransferase ModM3 phase varied either on or off.

scholarly journals Role of the Oligopeptide Permease ABC Transporter of Moraxella catarrhalis in Nutrient Acquisition and Persistence in the Respiratory Tract

2014 ◽  
Vol 82 (11) ◽  
pp. 4758-4766 ◽  
Author(s):  
Megan M. Jones ◽  
Antoinette Johnson ◽  
Mary Koszelak-Rosenblum ◽  
Charmaine Kirkham ◽  
Aimee L. Brauer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Respiratory Tract ◽  
Moraxella Catarrhalis ◽  
Minimal Medium ◽  
Substrate Binding ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Content Type ◽  
Oligopeptide Permease ◽  
Substrate Binding Protein

ABSTRACTMoraxella catarrhalisis a strict human pathogen that causes otitis media in children and exacerbations of chronic obstructive pulmonary disease in adults, resulting in significant worldwide morbidity and mortality.M. catarrhalishas a growth requirement for arginine; thus, acquiring arginine is important for fitness and survival.M. catarrhalishas a putative oligopeptide permease ABC transport operon (opp) consisting of five genes (oppB,oppC,oppD,oppF, andoppA), encoding two permeases, two ATPases, and a substrate binding protein. Thermal shift assays showed that the purified recombinant substrate binding protein OppA binds to peptides 3 to 16 amino acid residues in length regardless of the amino acid composition. A mutant in which theoppBCDFAgene cluster is knocked out showed impaired growth in minimal medium where the only source of arginine came from a peptide 5 to 10 amino acid residues in length. Whether methylated arginine supports growth ofM. catarrhalisis important in understanding fitness in the respiratory tract because methylated arginine is abundant in host tissues. No growth of wild-typeM. catarrhaliswas observed in minimal medium in which arginine was present only in methylated form, indicating that the bacterium requiresl-arginine. AnoppAknockout mutant showed marked impairment in its capacity to persist in the respiratory tract compared to the wild type in a mouse pulmonary clearance model. We conclude that the Opp system mediates both uptake of peptides and fitness in the respiratory tract.

scholarly journals Vaccines for Nontypeable Haemophilus influenzae: the Future Is Now

2015 ◽  
Vol 22 (5) ◽  
pp. 459-466 ◽  
Author(s):  
Timothy F. Murphy
Keyword(s):  
Haemophilus Influenzae ◽  
Otitis Media ◽  
Hospital Admissions ◽  
Vaccine Antigen ◽  
Research Progress ◽  
Effective Vaccine ◽  
Chronic Obstructive ◽  
Suppurative Otitis Media ◽  
Content Type ◽  
Tract Infections

ABSTRACTInfections due to nontypeableHaemophilus influenzaeresult in enormous global morbidity in two clinical settings: otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Recurrent otitis media affects up to 20% of children and results in hearing loss, delays in speech and language development and, in developing countries, chronic suppurative otitis media. Infections in people with COPD result in clinic and emergency room visits, hospital admissions, and respiratory failure. An effective vaccine would prevent morbidity, help control health care costs, and reduce antibiotic use, a major contributor to the global crisis in bacterial antibiotic resistance. The widespread use of the pneumococcal conjugate vaccines is causing a relative increase inH. influenzaeotitis media. The partial protection againstH. influenzaeotitis media induced by the pneumococcalH. influenzaeprotein D conjugate vaccine represents a proof of principle of the feasibility of a vaccine for nontypeableH. influenzae. An ideal vaccine antigen should be conserved among strains, have abundant epitopes on the bacterial surface, be immunogenic, and induce protective immune responses. Several surface proteins ofH. influenzaehave been identified as potential vaccine candidates and are in various stages of development. With continued research, progress toward a broadly effective vaccine to prevent infections caused by nontypeableH. influenzaeis expected over the next several years.

scholarly journals NontypeableHaemophilus influenzaeLipooligosaccharide Expresses a Terminal KetodeoxyoctanateIn Vivo, Which Can Be Used as a Target for Bactericidal Antibody

mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Michael A. Apicella ◽  
Jeremy Coffin ◽  
Margaret Ketterer ◽  
Deborah M. B. Post ◽  
Christopher J. Day ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Complex Structure ◽  
Phase Variation ◽  
Chronic Obstructive Lung Disease ◽  
Vaccine Antigen ◽  
Effective Vaccine ◽  
Chronic Obstructive ◽  
Branch Points ◽  
Content Type

ABSTRACTNontypeableHaemophilus influenzae(NTHi) is an important pathogen in individuals of all ages. The lipooligosaccharide (LOS) of NTHi has evolved a complex structure that can be attributed to a multiplicity of glycosyltransferases, the random switching of glycosyltransferase gene expression via phase variation, and the complex structure of its core region with multiple glycoform branch points. This article adds to that complexity by describing a multifunctional enzyme (LsgB) which optimally functions when the species is grown on a solid surface and which can add either a ketodeoxyoctanoate (KDO) or anN-acetylneuramic acid (Neu5Ac) moiety to a terminalN-acetyllactosamine structure of LOS. Our studies show that expression oflsgBis reduced four- to sixfold when NTHi is grown in broth. The substrate that the enzyme utilizes is dependent upon the concentration of free Neu5Ac (between 1 and 10 µg/ml) in the environment. In environments in which Neu5Ac is below that level, the enzyme utilizes endogenous CMP-KDO as the substrate. Our studies show that duringin vivogrowth in an NTHi biofilm, the KDO moiety is expressed by the organism. Monoclonal antibody 6E4, which binds KDO, is bactericidal for NTHi strains that express the KDO epitope at high levels. In a survey of 33 NTHi strains isolated from healthy and diseased individuals, the antibody was bactericidal (>90% kill) for 12 strains (36%). These studies open up the possibility of using a KDO-based glycoconjugate vaccine as part of a multicomponent vaccine against NTHi.IMPORTANCENontypeableHaemophilus influenzaeis an important pathogen in middle ear infections in children, sinusitis in adults, and acute bronchitis in individuals with chronic obstructive lung disease. The organism is very well adapted to the human host environment, and this has hindered successful development of an effective vaccine. In this article, we describe a mechanism by which the bacteria decorates its surface lipooligosaccharide with a sugar unique to Gram-negative bacteria, ketodeoxyoctanoate (KDO). This sugar decoration is present during active infection and we have shown that an antibody directed against this sugar can result in killing of the organism. These data demonstrate that the lipooligosaccharide ketodeoxyoctanoate epitope may be a novel NTHi-specific candidate vaccine antigen.

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