scholarly journals Nontypeable Haemophilus influenzae Type IV Pilus Mediates Augmented Adherence to Rhinovirus-Infected Human Airway Epithelial Cells

2020 ◽  
Vol 88 (9) ◽  
Author(s):  
Stephen L. Toone ◽  
Michelle Ratkiewicz ◽  
Laura A. Novotny ◽  
Binh L. Phong ◽  
Lauren O. Bakaletz
Keyword(s):  
Epithelial Cells ◽  
Respiratory Tract ◽  
Haemophilus Influenzae ◽  
Host Cell ◽  
Bacterial Load ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Upper Respiratory Tract ◽  
Type Iv ◽  
Upper Respiratory

ABSTRACT Human rhinovirus (hRV) is frequently detected in the upper respiratory tract, and symptomatic infection is associated with an increased nasopharyngeal bacterial load, with subsequent development of secondary bacterial diseases. Nontypeable Haemophilus influenzae (NTHI) is a commensal bacterial species of the human nasopharynx; however, in the context of prior or concurrent upper respiratory tract viral infection, this bacterium commonly causes multiple diseases throughout the upper and lower respiratory tracts. The present study was conducted to determine the mechanism(s) by which hRV infection promotes the development of NTHI-induced diseases. We showed that hRV infection of polarized primary human airway epithelial cells resulted in increased adherence of NTHI, due in part to augmented expression of CEACAM1 and ICAM1, host cell receptors to which NTHI binds via engagement of multiple adhesins. Antibody blockade of these host cell receptors significantly reduced NTHI adherence. With a specific focus on the NTHI type IV pilus (T4P), which we have previously shown binds to ICAM1, an essential adhesin and virulence determinant, we next showed that T4P-directed antibody blockade significantly reduced NTHI adherence to hRV-infected airway cells and, further, that expression of this adhesin was required for the enhanced adherence observed. Collectively, these data provide a mechanism by which “the common cold” promotes diseases due to NTHI, and they add further support for the use of PilA (the majority subunit of T4P) as a vaccine antigen, since antibodies directed against PilA are expected to limit the notably increased bacterial load associated with hRV coinfection and thereby to prevent secondary NTHI-induced diseases of the respiratory tract.

scholarly journals Nontypeable Haemophilus influenzae Responds to Virus-Infected Cells with a Significant Increase in Type IV Pilus Expression

mSphere ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Elaine M. Mokrzan ◽  
Kolapo A. Dairo ◽  
Laura A. Novotny ◽  
Lauren O. Bakaletz
Keyword(s):  
Epithelial Cells ◽  
Virus Infection ◽  
Respiratory Tract ◽  
Haemophilus Influenzae ◽  
Chronic Obstructive ◽  
Upper Respiratory Tract ◽  
Type Iv Pilus ◽  
Content Type ◽  
Type Iv ◽  
Upper Respiratory

ABSTRACT Nontypeable Haemophilus influenzae (NTHI) colonizes the human nasopharynx, but when the host immune response is dysregulated by upper respiratory tract (URT) virus infection, NTHI can gain access to more distal airway sites and cause disease. The NTHI type IV pilus (T4P) facilitates adherence, benign colonization, and infection, and its majority subunit PilA is in clinical trials as a vaccinogen. To further validate the strategy of immunization with PilA against multiple NTHI-induced diseases, it is important to demonstrate T4P expression under microenvironmental conditions that predispose to NTHI infection of the airway. Because URT infection commonly facilitates NTHI-induced diseases, we examined the influence of ongoing virus infection of respiratory tract epithelial cells on NTHI T4P expression in vitro. Polarized primary human airway epithelial cells (HAEs) were sequentially inoculated with one of three common URT viruses, followed by NTHI. Use of a reporter construct revealed that NTHI upregulated pilA promoter activity when cultured with HAEs infected with adenovirus (AV), respiratory syncytial virus (RSV), or rhinovirus (RV) versus that in mock-infected HAEs. Consistent with these results, pilA expression and relative PilA/pilin abundance, as assessed by quantitative reverse transcription-PCR (qRT-PCR) and immunoblot, respectively, were also significantly increased when NTHI was cultured with virus-infected HAEs. Collectively, our data strongly suggest that under conditions of URT virus infection, PilA vaccinogen induction of T4P-directed antibodies is likely to be highly effective against multiple NTHI-induced diseases by interfering with T4P-mediated adherence. We hypothesize that this outcome could thereby limit or prevent the increased load of NTHI in the nasopharynx that characteristically precedes these coinfections. IMPORTANCE Nontypeable Haemophilus influenzae (NTHI) is the predominant bacterial causative agent of many chronic and recurrent diseases of the upper and lower respiratory tracts. NTHI-induced chronic rhinosinusitis, otitis media, and exacerbations of cystic fibrosis and chronic obstructive pulmonary disease often develop during or just after an upper respiratory tract viral infection. We have developed a vaccine candidate immunogen for NTHI-induced diseases that targets the majority subunit (PilA) of the type IV twitching pilus (T4P), which NTHI uses to adhere to respiratory tract epithelial cells and that also plays a role in disease. Here, we showed that NTHI cocultured with virus-infected respiratory tract epithelial cells express significantly more of the vaccine-targeted T4P than NTHI that encounters mock-infected (healthy) cells. These results strongly suggest that a vaccine strategy that targets the NTHI T4P will be effective under the most common predisposing condition: when the human host has a respiratory tract virus infection.

scholarly journals Expression of the Nontypeable Haemophilus influenzae Type IV Pilus Is Stimulated by Coculture with Host Respiratory Tract Epithelial Cells

2019 ◽  
Vol 87 (12) ◽  
Author(s):  
Elaine M. Mokrzan ◽  
Taylor J. Johnson ◽  
Lauren O. Bakaletz
Keyword(s):  
Epithelial Cells ◽  
Respiratory Tract ◽  
Haemophilus Influenzae ◽  
Promoter Activity ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Type Iv Pilus ◽  
Human Airway ◽  
Type Iv ◽  
Pilin Protein

ABSTRACT The type IV pilus (Tfp) of nontypeable Haemophilus influenzae (NTHI) mediates adherence, colonization, motility, and biofilm formation, and the major protein subunit, PilA, is a promising vaccine candidate. Thus, it is crucial to understand how Tfp expression is regulated within the microenvironments of the human nasopharynx, which NTHI colonizes asymptomatically, and the more distal regions of the respiratory tract where NTHI-induced diseases occur. Here, we examined the effects of coculture of NTHI with human airway epithelial cells and heme availability on Tfp expression at temperatures typical of the human nasopharynx (34°C) or warmer anatomical sites during infection (37°C). Tfp expression was estimated by pilA promoter activity, pilA gene expression, and relative abundances of PilA and pilin protein. The results revealed that at both temperatures, NTHI cocultured with airway epithelial cells demonstrated significantly greater expression of pilA, PilA/pilin protein, and likely, fully assembled Tfp than NTHI cultured on an abiotic surface. Because NTHI is a heme auxotroph, we hypothesized that availability of heme from host cells might be a signal for Tfp expression. Thereby, we cultured NTHI in iron-limited medium, and we observed that supplementation with heme significantly increased pilA promoter activity. Collectively, our data suggested that NTHI Tfp expression was stimulated by soluble factor(s) released by epithelial cells, which are present in all microenvironments of the respiratory tract. The expression of this target antigen under conditions that mimic the human airway strongly supports the rationale for the use of PilA as a vaccine immunogen to prevent NTHI-induced diseases of the respiratory tract.

scholarly journals A Type IV Secretion System Contributes to Intracellular Survival and Replication of Burkholderia cenocepacia

2008 ◽  
Vol 76 (12) ◽  
pp. 5447-5455 ◽  
Author(s):  
S. Umadevi Sajjan ◽  
Lisa A. Carmody ◽  
Carlos F. Gonzalez ◽  
John J. LiPuma
Keyword(s):  
Epithelial Cells ◽  
Airway Epithelial Cells ◽  
Secretion System ◽  
Type Iv Secretion ◽  
Endocytic Pathway ◽  
Burkholderia Cenocepacia ◽  
Type Iv Secretion System ◽  
Airway Epithelial ◽  
Wild Type ◽  
Type Iv

ABSTRACT Burkholderia cenocepacia is an important respiratory pathogen in persons with cystic fibrosis (CF). Recent studies indicate that B. cenocepacia survives within macrophages and airway epithelial cells in vitro by evading endosome-lysosome fusion. We investigated the role of a plasmid-encoded type IV secretion system in the intracellular survival, replication, and processing of B. cenocepacia. Both a wild-type strain (K56-2) and its type IV secretion system mutant (designated LC101) entered and replicated in CF airway epithelial cells and monocyte-derived macrophages. However, significantly more intracellular K56-2 than LC101 bacteria were found in both cell types at 24 h postinfection. Colocalization of bacteria with markers of the classical endocytic pathway indicated that although both K56-2 and LC101 reside transiently in early endosomes, a greater proportion of the mutant bacteria are targeted to lysosomal degradation. In contrast, wild-type bacteria escape from the classical endocytic pathway and traffic to the endoplasmic reticulum, where they replicate. Our results show that the intracellular processing of B. cenocepacia is similar in both professional and nonprofessional phagocytes and that a functional plasmid-encoded type IV secretion system contributes to the survival and replication of B. cenocepacia in eukaryotic cells.

scholarly journals Epidemiological Markers for Interactions AmongStreptococcus pneumoniae,Haemophilus influenzae, andStaphylococcus aureusin Upper Respiratory Tract Carriage

2015 ◽  
Vol 213 (10) ◽  
pp. 1596-1605 ◽  
Author(s):  
Joseph A. Lewnard ◽  
Noga Givon-Lavi ◽  
Amit Huppert ◽  
Melinda M. Pettigrew ◽  
Gili Regev-Yochay ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Haemophilus Influenzae ◽  
Upper Respiratory Tract ◽  
Upper Respiratory ◽  
Epidemiological Markers
Sign in / Sign up

Export Citation Format

Share Document