scholarly journals Pneumococcal Neuraminidase A (NanA) Promotes Biofilm Formation and Synergizes with Influenza A Virus in Nasal Colonization and Middle Ear Infection

2017 ◽  
Vol 85 (4) ◽  
Author(s):  
John T. Wren ◽  
Lance K. Blevins ◽  
Bing Pang ◽  
Ankita Basu Roy ◽  
Melissa B. Oliver ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Middle Ear ◽  
Influenza A ◽  
Nasal Colonization ◽  
Ear Infection ◽  
Content Type ◽  
Public Health Burden ◽  
Middle Ear Infection

ABSTRACT Even in the vaccine era, Streptococcus pneumoniae (the pneumococcus) remains a leading cause of otitis media, a significant public health burden, in large part because of the high prevalence of nasal colonization with the pneumococcus in children. The primary pneumococcal neuraminidase, NanA, which is a sialidase that catalyzes the cleavage of terminal sialic acids from host glycoconjugates, is involved in both of these processes. Coinfection with influenza A virus, which also expresses a neuraminidase, exacerbates nasal colonization and disease by S. pneumoniae, in part via the synergistic contributions of the viral neuraminidase. The specific role of its pneumococcal counterpart, NanA, in this interaction, however, is less well understood. We demonstrate in a mouse model that NanA-deficient pneumococci are impaired in their ability to cause both nasal colonization and middle ear infection. Coinfection with neuraminidase-expressing influenza virus and S. pneumoniae potentiates both colonization and infection but not to wild-type levels, suggesting an intrinsic role of NanA. Using in vitro models, we show that while NanA contributes to both epithelial adherence and biofilm viability, its effect on the latter is actually independent of its sialidase activity. These data indicate that NanA contributes both enzymatically and nonenzymatically to pneumococcal pathogenesis and, as such, suggest that it is not a redundant bystander during coinfection with influenza A virus. Rather, its expression is required for the full synergism between these two pathogens.

scholarly journals Influenza A Virus Alters Pneumococcal Nasal Colonization and Middle Ear Infection Independently of Phase Variation

2014 ◽  
Vol 82 (11) ◽  
pp. 4802-4812 ◽  
Author(s):  
John T. Wren ◽  
Lance K. Blevins ◽  
Bing Pang ◽  
Lauren B. King ◽  
Antonia C. Perez ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Otitis Media ◽  
Influenza A Virus ◽  
Middle Ear ◽  
Influenza A ◽  
Phase Variation ◽  
Infection Model ◽  
Ear Infection ◽  
Middle Ear Infection ◽  
Phase Variants

ABSTRACTStreptococcus pneumoniae(pneumococcus) is both a widespread nasal colonizer and a leading cause of otitis media, one of the most common diseases of childhood. Pneumococcal phase variation influences both colonization and disease and thus has been linked to the bacteria's transition from colonizer to otopathogen. Further contributing to this transition, coinfection with influenza A virus has been strongly associated epidemiologically with the dissemination of pneumococci from the nasopharynx to the middle ear. Using a mouse infection model, we demonstrated that coinfection with influenza virus and pneumococci enhanced both colonization and inflammatory responses within the nasopharynx and middle ear chamber. Coinfection studies were also performed using pneumococcal populations enriched for opaque or transparent phase variants. As shown previously, opaque variants were less able to colonize the nasopharynx.In vitro, this phase also demonstrated diminished biofilm viability and epithelial adherence. However, coinfection with influenza virus ameliorated this colonization defectin vivo. Further, viral coinfection ultimately induced a similar magnitude of middle ear infection by both phase variants. These data indicate that despite inherent differences in colonization, the influenza A virus exacerbation of experimental middle ear infection is independent of the pneumococcal phase. These findings provide new insights into the synergistic link between pneumococcus and influenza virus in the context of otitis media.

scholarly journals Antibodies Mediate Formation of Neutrophil Extracellular Traps in the Middle Ear and Facilitate Secondary Pneumococcal Otitis Media

2013 ◽  
Vol 82 (1) ◽  
pp. 364-370 ◽  
Author(s):  
Kirsty R. Short ◽  
Maren von Köckritz-Blickwede ◽  
Jeroen D. Langereis ◽  
Keng Yih Chew ◽  
Emma R. Job ◽  
...  
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
Influenza A ◽  
Bacterial Load ◽  
Neutrophil Extracellular Trap ◽  
Content Type ◽  
Middle Ear Infection ◽  
Host Inflammatory Response ◽  
Insight Into ◽  
Bacterial Outgrowth

ABSTRACTOtitis media (OM) (a middle ear infection) is a common childhood illness that can leave some children with permanent hearing loss. OM can arise following infection with a variety of different pathogens, including a coinfection with influenza A virus (IAV) andStreptococcus pneumoniae(the pneumococcus). We and others have demonstrated that coinfection with IAV facilitates the replication of pneumococci in the middle ear. Specifically, we used a mouse model of OM to show that IAV facilitates the outgrowth ofS. pneumoniaein the middle ear by inducing middle ear inflammation. Here, we seek to understand how the host inflammatory response facilitates bacterial outgrowth in the middle ear. Using B cell-deficient infant mice, we show that antibodies play a crucial role in facilitating pneumococcal replication. We subsequently show that this is due to antibody-dependent neutrophil extracellular trap (NET) formation in the middle ear, which, instead of clearing the infection, allows the bacteria to replicate. We further demonstrate the importance of these NETs as a potential therapeutic target through the transtympanic administration of a DNase, which effectively reduces the bacterial load in the middle ear. Taken together, these data provide novel insight into how pneumococci are able to replicate in the middle ear cavity and induce disease.

scholarly journals Dynamic Changes in the Streptococcus pneumoniae Transcriptome during Transition from Biofilm Formation to Invasive Disease upon Influenza A Virus Infection

2014 ◽  
Vol 82 (11) ◽  
pp. 4607-4619 ◽  
Author(s):  
Melinda M. Pettigrew ◽  
Laura R. Marks ◽  
Yong Kong ◽  
Janneane F. Gent ◽  
Hazeline Roche-Hakansson ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Influenza A Virus ◽  
Influenza A ◽  
Lactate Production ◽  
Invasive Disease ◽  
Content Type ◽  
Induced Changes ◽  
Upregulated Genes

ABSTRACTStreptococcus pneumoniaeis a leading cause of infectious disease globally. Nasopharyngeal colonization occurs in biofilms and precedes infection. Prior studies have indicated that biofilm-derived pneumococci are avirulent. However, influenza A virus (IAV) infection releases virulent pneumococci from biofilmsin vitroandin vivo. Triggers of dispersal include IAV-induced changes in the nasopharynx, such as increased temperature (fever) and extracellular ATP (tissue damage). We used whole-transcriptome shotgun sequencing (RNA-seq) to compare theS. pneumoniaetranscriptome in biofilms, bacteria dispersed from biofilms after exposure to IAV, febrile-range temperature, or ATP, and planktonic cells grown at 37°C. Compared with biofilm bacteria, actively dispersedS. pneumoniae, which were more virulent in invasive disease, upregulated genes involved in carbohydrate metabolism. Enzymatic assays for ATP and lactate production confirmed that dispersed pneumococci exhibited increased metabolism compared to those in biofilms. Dispersed pneumococci also upregulated genes associated with production of bacteriocins and downregulated colonization-associated genes related to competence, fratricide, and the transparent colony phenotype. IAV had the largest impact on the pneumococcal transcriptome. Similar transcriptional differences were also observed when actively dispersed bacteria were compared with avirulent planktonic bacteria. Our data demonstrate complex changes in the pneumococcal transcriptome in response to IAV-induced changes in the environment. Our data suggest that disease is caused by pneumococci that are primed to move to tissue sites with altered nutrient availability and to protect themselves from the nasopharyngeal microflora and host immune response. These data help explain pneumococcal virulence after IAV infection and have important implications for studies ofS. pneumoniaepathogenesis.

scholarly journals Role of neuromedin B and its receptor in the innate immune responses against influenza A virus infection in vitro and in vivo

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Guihong Yang ◽  
Huipeng Huang ◽  
Mengyao Tang ◽  
Zifeng Cai ◽  
Cuiqin Huang ◽  
...  
Keyword(s):  
Virus Infection ◽  
Influenza A Virus ◽  
Influenza A ◽  
A549 Cells ◽  
Virus Challenge ◽  
Neuromedin B ◽  
Influenza A Virus Infection

Abstract The peptide neuromedin B (NMB) and its receptor (NMBR) represent a system (NMB/NMBR) of neuromodulation. Here, it was demonstrated that the expression of NMBR in cells or murine lung tissues was clearly upregulated in response to H1N1/PR8 influenza A virus infection. Furthermore, the in vitro and in vivo activities of NMB/NMBR during PR8 infection were investigated. It was observed that A549 cells lacking endogenous NMBR were more susceptible to virus infection than control cells, as evidenced by the increased virus production in the cells. Interestingly, a significant decrease in IFN-α and increased IL-6 expression were observed in these cells. The role of this system in innate immunity against PR8 infection was probed by treating mice with NMB. The NMB-treated mice were less susceptible to virus challenge, as evidenced by increased survival, increased body weight, and decreased viral NP expression compared with the control animals. Additionally, the results showed that exogenous NMB not only enhanced IFN-α expression but also appeared to inhibit the expression of NP and IL-6 in PR8-infected cells and animals. As expected, opposing effects were observed in the NMBR antagonist-treated cells and mice, which further confirmed the effects of NMB. Together, these data suggest that NMB/NMBR may be an important component of the host defence against influenza A virus infection. Thus, these proteins may serve as promising candidates for the development of novel antiviral drugs.

The role of the N-terminal caspase cleavage site in the nucleoprotein of influenza A virus in vitro and in vivo

2007 ◽  
Vol 153 (3) ◽  
pp. 427-434 ◽  
Author(s):  
A. S. Lipatov ◽  
H.-L. Yen ◽  
R. Salomon ◽  
H. Ozaki ◽  
E. Hoffmann ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Cleavage Site ◽  
Influenza A ◽  
Caspase Cleavage ◽  
Caspase Cleavage Site

Abnormal middle ear pressures during experimental influenza A virus infection — role of Eustachian tube function

2000 ◽  
Vol 27 (4) ◽  
pp. 323-326 ◽  
Author(s):  
William J Doyle ◽  
James T Seroky ◽  
Betty L Angelini ◽  
Mehmet Gulhan ◽  
David P Skoner ◽  
...  
Keyword(s):  
Virus Infection ◽  
Influenza A Virus ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Influenza A ◽  
Eustachian Tube Function ◽  
Tube Function ◽  
Influenza A Virus Infection ◽  
Experimental Influenza

scholarly journals Role of the B Allele of Influenza A Virus Segment 8 in Setting Mammalian Host Range and Pathogenicity

2016 ◽  
Vol 90 (20) ◽  
pp. 9263-9284 ◽  
Author(s):  
Matthew L. Turnbull ◽  
Helen M. Wise ◽  
Marlynne Q. Nicol ◽  
Nikki Smith ◽  
Rebecca L. Dunfee ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
H3n2 Virus ◽  
Mammalian Host ◽  
Influenza A Viruses ◽  
Content Type ◽  
Avian Virus ◽  
Segment 8 ◽  
Reassortant Viruses

ABSTRACTTwo alleles of segment 8 (NS) circulate in nonchiropteran influenza A viruses. The A allele is found in avian and mammalian viruses, but the B allele is viewed as being almost exclusively found in avian viruses. This might reflect the fact that one or both of its encoded proteins (NS1 and NEP) are maladapted for replication in mammalian hosts. To test this, a number of clade A and B avian virus-derived NS segments were introduced into human H1N1 and H3N2 viruses. In no case was the peak virus titer substantially reduced following infection of various mammalian cell types. Exemplar reassortant viruses also replicated to similar titers in mice, although mice infected with viruses with the avian virus-derived segment 8s had reduced weight loss compared to that achieved in mice infected with the A/Puerto Rico/8/1934 (H1N1) parent.In vitro, the viruses coped similarly with type I interferons. Temporal proteomics analysis of cellular responses to infection showed that the avian virus-derived NS segments provoked lower levels of expression of interferon-stimulated genes in cells than wild type-derived NS segments. Thus, neither the A nor the B allele of avian virus-derived NS segments necessarily attenuates virus replication in a mammalian host, although the alleles can attenuate disease. Phylogenetic analyses identified 32 independent incursions of an avian virus-derived A allele into mammals, whereas 6 introductions of a B allele were identified. However, A-allele isolates from birds outnumbered B-allele isolates, and the relative rates ofAves-to-Mammaliatransmission were not significantly different. We conclude that while the introduction of an avian virus segment 8 into mammals is a relatively rare event, the dogma of the B allele being especially restricted is misleading, with implications in the assessment of the pandemic potential of avian influenza viruses.IMPORTANCEInfluenza A virus (IAV) can adapt to poultry and mammalian species, inflicting a great socioeconomic burden on farming and health care sectors. Host adaptation likely involves multiple viral factors. Here, we investigated the role of IAV segment 8. Segment 8 has evolved into two distinct clades: the A and B alleles. The B-allele genes have previously been suggested to be restricted to avian virus species. We introduced a selection of avian virus A- and B-allele segment 8s into human H1N1 and H3N2 virus backgrounds and found that these reassortant viruses were fully competent in mammalian host systems. We also analyzed the currently available public data on the segment 8 gene distribution and found surprisingly little evidence for specific avian host restriction of the B-clade segment. We conclude that B-allele segment 8 genes are, in fact, capable of supporting infection in mammals and that they should be considered during the assessment of the pandemic risk of zoonotic influenza A viruses.

scholarly journals Host Cellular Protein TRAPPC6AΔ Interacts with Influenza A Virus M2 Protein and Regulates Viral Propagation by Modulating M2 Trafficking

2016 ◽  
Vol 91 (1) ◽  
Author(s):  
Pengyang Zhu ◽  
Libin Liang ◽  
Xinyuan Shao ◽  
Weiyu Luo ◽  
Shuitao Jiang ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Influenza A Virus ◽  
Influenza A ◽  
Secretory Pathway ◽  
Host Factors ◽  
Apical Plasma Membrane ◽  
M2 Protein ◽  
Internal Deletion

ABSTRACT Influenza A virus (IAV) matrix protein 2 (M2) plays multiple roles in the early and late phases of viral infection. Once synthesized, M2 is translocated to the endoplasmic reticulum (ER), travels to the Golgi apparatus, and is sorted at the trans-Golgi network (TGN) for transport to the apical plasma membrane, where it functions in virus budding. We hypothesized that M2 trafficking along with its secretory pathway must be finely regulated, and host factors could be involved in this process. However, no studies examining the role of host factors in M2 posttranslational transport have been reported. Here, we used a yeast two-hybrid (Y2H) system to screen for host proteins that interact with the M2 protein and identified transport protein particle complex 6A (TRAPPC6A) as a potential binding partner. We found that both TRAPPC6A and its N-terminal internal-deletion isoform, TRAPPC6A delta (TRAPPC6AΔ), interact with M2. Truncation and mutation analyses showed that the highly conserved leucine residue at position 96 of M2 is critical for mediating this interaction. The role of TRAPPC6AΔ in the viral life cycle was investigated by the knockdown of endogenous TRAPPC6AΔ with small interfering RNA (siRNA) and by generating a recombinant virus that was unable to interact with TRAPPC6A/TRAPPC6AΔ. The results indicated that TRAPPC6AΔ, through its interaction with M2, slows M2 trafficking to the apical plasma membrane, favors viral replication in vitro, and positively modulates virus virulence in mice. IMPORTANCE The influenza A virus M2 protein regulates the trafficking of not only other proteins but also itself along the secretory pathway. However, the host factors involved in the regulation of the posttranslational transport of M2 are largely unknown. In this study, we identified TRAPPC6A and its N-terminal internal-deletion isoform, TRAPPC6AΔ, as interacting partners of M2. We found that the leucine (L) residue at position 96 of M2 is critical for mediating this interaction, which leads us to propose that the high level of conservation of 96L is a consequence of M2 adaptation to its interacting host factor TRAPPC6A/TRAPPC6AΔ. Importantly, we discovered that TRAPPC6AΔ can positively regulate viral replication in vitro by modulating M2 trafficking to the plasma membrane.

scholarly journals MARCH8 inhibits influenza A virus infection by targeting viral M2 protein for ubiquitination-dependent degradation in lysosomes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaoman Liu ◽  
Fengwen Xu ◽  
Lili Ren ◽  
Fei Zhao ◽  
Yu Huang ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Cellular Membrane ◽  
Immune Defense ◽  
M2 Protein ◽  
E3 Ligases ◽  
Underlying Mechanisms ◽  
The Stability

AbstractThe membrane-associated RING-CH (MARCH) proteins are E3 ligases that regulate the stability of various cellular membrane proteins. MARCH8 has been reported to inhibit the infection of HIV-1 and a few other viruses, thus plays an important role in host antiviral defense. However, the antiviral spectrum and the underlying mechanisms of MARCH8 are incompletely defined. Here, we demonstrate that MARCH8 profoundly inhibits influenza A virus (IAV) replication both in vitro and in mice. Mechanistically, MARCH8 suppresses IAV release through redirecting viral M2 protein from the plasma membrane to lysosomes for degradation. Specifically, MARCH8 catalyzes the K63-linked polyubiquitination of M2 at lysine residue 78 (K78). A recombinant A/Puerto Rico/8/34 virus carrying the K78R M2 protein shows greater replication and more severe pathogenicity in cells and mice. More importantly, we found that the M2 protein of the H1N1 IAV has evolved to acquire non-lysine amino acids at positions 78/79 to resist MARCH8-mediated ubiquitination and degradation. Together, our data support the important role of MARCH8 in host anti-IAV intrinsic immune defense by targeting M2, and suggest the inhibitory pressure of MARCH8 on H1N1 IAV transmission in the human population.

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