title: RbsB (NTHI_0632) mediates quorum signal uptake in nontypeable Haemophilus influenzae strain 86-028NP.
abstract: Nontypeable Haemophilus influenzae (NTHI) is a respiratory commensal and opportunistic pathogen, which persists within biofilms on airway mucosal surfaces. For many species, biofilm formation is impacted by quorum signalling. Our prior work shows that production of autoinducer-2 (AI-2) promotes biofilm development and persistence for NTHI 86-028NP. NTHI 86-028NP encodes an ABC transporter annotated as a ribose transport system that includes a protein (RbsB) with similarity to the Escherichia coli LsrB and Aggregatibacter actinomycetemcomitans RbsB proteins that bind AI-2. In this study, inactivation of rbsB significantly reduced uptake of AI-2 and the AI-2 precursor dihydroxypentanedione (DPD) by NTHI 86-028NP. Moreover, DPD uptake was not competitively inhibited by ribose or other pentose sugars. Transcript levels of rbsB increased in response to DPD and as bacteria approached stationary-phase growth. The NTHI 86-028NP rbsB mutant also formed biofilms with significantly reduced thickness and total biomass and reduced surface phosphorylcholine, similar to a luxS mutant. Infection studies revealed that loss of rbsB impaired bacterial persistence in the chinchilla middle ear, similar to our previous results with luxS mutants. Based on these data, we conclude that in NTHI 86-028NP, RbsB is a LuxS/AI-2 regulated protein that is required for uptake of and response to AI-2.
authors.affiliation: Department of Microbiology and Immunology, Wake Forest University Health Sciences, Winston Salem, NC 27157, USA.
authors.forename: Chelsie E
authors.initials: CE
authors.lastname: Armbruster
authors.forename: Bing
authors.initials: B
authors.lastname: Pang
authors.forename: Kyle
authors.initials: K
authors.lastname: Murrah
authors.forename: Richard A
authors.initials: RA
authors.lastname: Juneau
authors.forename: Antonia C
authors.initials: AC
authors.lastname: Perez
authors.forename: Kristin E D
authors.initials: KE
authors.lastname: Weimer
authors.forename: W Edward
authors.initials: WE
authors.lastname: Swords
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D018441:Biofilms / Q000254:growth & development; D018533:Biomass; D002682:Chinchilla; D004195:Disease Models, Animal; D004432:Ear, Middle / Q000382:microbiology; D017353:Gene Deletion; D020869:Gene Expression Profiling; D006192:Haemophilus Infections / Q000382:microbiology; D006193:Haemophilus influenzae / Q000235:genetics / Q000502:physiology*; D006714:Homoserine / Q000031:analogs & derivatives / Q000378:metabolism; D007783:Lactones / Q000378:metabolism; D010420:Pentanes / Q000378:metabolism; D053038:Quorum Sensing; D015398:Signal Transduction
chemical_list: C493138:4,5-dihydroxy-2,3-pentanedione; D018528:ATP-Binding Cassette Transporters; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D010420:Pentanes; D006714:Homoserine