The pilus-induced Ca2+ flux triggers lysosome exocytosis and increases the amount of Lamp1 accessible to Neisseria IgA1 protease

Ayala, B. Patricia; Vasquez, Brandi; Clary, Susan; Tainer, John A.; Rodland, Karin D.; So, Magdalene

doi:10.1046/j.1462-5822.2001.00112.x

Cited by 44 publications

(60 citation statements)

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“…For the experiments described in this work, A431 cells (20), an epithelial cell line derived from the endocervix (56), were used. Gonococci have been shown to adhere to and invade A431 cells at a high frequency (3,30,43,48,76), and there have been several reports investigating the response of these cells to gonococcal adherence at the molecular level (4,5,7,43).…”

Section: Resultsmentioning

confidence: 99%

“…The primary adhesins on the gonococcal cell surface are the type IV pili (77,78), although there are additional surface structures of the bacterium that can participate in adherence (18,22,33,37,46,47,67,82,84). Binding of gonococcal pili to host cells results in the induction of signal transduction pathways in the eukaryotic cell that affect multiple cellular processes (4,34,43,57,58,62). Adherence of piliated gonococci to epithelial cells also results in a variety of rearrangements in the components of the cellular cytoskeleton (reviewed in reference 50) as well as significant changes in host cell gene expression (61).…”

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confidence: 99%

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Global Gene Expression and the Role of Sigma Factors in Neisseria gonorrhoeae in Interactions with Epithelial Cells

Lenz

Arvidson

2005

Infect Immun

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Like many bacterial pathogens, Neisseria gonorrhoeae must adapt to environmental changes in order to successfully colonize and proliferate in a new host. Modulation of gene expression in response to environmental signals is an efficient mechanism used by bacteria to achieve this goal. Using DNA microarrays and a tissue culture model for gonococcal infection, we examined global changes in gene expression in N. gonorrhoeae in response to adherence to host cells. Among those genes induced upon adherence to human epithelial cells in culture was rpoH, which encodes a homolog of the heat shock sigma factor, 32 (RpoH), as well as genes of the RpoH regulon, groEL and groES. Attempts to construct an rpoH null mutant in N. gonorrhoeae were unsuccessful, suggesting that RpoH is essential for viability of N. gonorrhoeae. The extracytoplasmic sigma factor, RpoE ( E ), while known to regulate rpoH in other bacteria, was found not to be necessary for the up-regulation of rpoH in gonococci upon adherence to host cells. To examine the role of RpoH in host cell interactions, an N. gonorrhoeae strain conditionally expressing rpoH was constructed. The results of our experiments showed that while induction of rpoH expression is not necessary for adherence of gonococci to epithelial cells, it is important for the subsequent invasion step, as gonococci depleted for rpoH invade cells two-to threefold less efficiently than a wild-type strain. Taken together, these results indicate that 32 , but not E , is important for the response of gonococci in the initial steps of an infection.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Global Gene Expression and the Role of Sigma Factors in Neisseria gonorrhoeae in Interactions with Epithelial Cells

Lenz

Arvidson

2005

Infect Immun

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“…However, because IgA1 protease cleavage of LAMP1 in vitro was less efficient at low pH than at neutral pH, it is hypothesized that cleavage takes place not in lysosomes but at the plasma membrane (43). Indeed, neisserial porin and pilin trigger endosome and lysosome exocytosis, redistributing LAMP1 to the plasma membrane, which is thought to reduce the total number of lysosomes in infected cells (50)(51)(52). Our data show that IgaB-mediated cleavage of LAMP1 is also more efficient at neutral pH, but we observed no redistribution of lysosomes in our infection model system.…”

Section: Discussionmentioning

confidence: 99%

Internalization and Trafficking of Nontypeable Haemophilus influenzae in Human Respiratory Epithelial Cells and Roles of IgA1 Proteases for Optimal Invasion and Persistence

2014

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Nontypeable Haemophilus influenzae (NTHI) is a leading cause of opportunistic infections of the respiratory tract in children and adults. Although considered an extracellular pathogen, NTHI has been observed repeatedly within and between cells of the human respiratory tract, and these observations have been correlated to symptomatic infection. These findings are intriguing in light of the knowledge that NTHI persists in the respiratory tract despite antibiotic therapy and the development of bactericidal antibodies. We hypothesized that intracellular NTHI avoids, escapes, or neutralizes the endolysosomal pathway and persists within human respiratory epithelial cells and that human IgA1 proteases are required for optimal internalization and persistence of NTHI. Virtually all strains encode a human IgA1 protease gene, igaA, and we previously characterized a novel human IgA1 protease gene, igaB, that is associated with disease-causing strains and is homologous to the IgA1 protease that is unique to pathogenic Neisseria spp. Here, we show that NTHI invades human bronchial epithelial cells in vitro in a lipid raft-independent manner, is subsequently trafficked via the endolysosomal pathway, and is killed in lysosomes after variable durations of persistence. IgaA is required for optimal invasion. IgaB appears to play little or no role in adherence or invasion but is required for optimal intracellular persistence of NTHI. IgaB cleaves lysosome-associated membrane protein 1 (LAMP1) at pHs characteristic of the plasma membrane, early endosome, late endosome, and lysosome. However, neither IgA1 protease inhibits acidification of intracellular vesicles containing NTHI. NTHI IgA1 proteases play important but different roles in NTHI invasion and trafficking in respiratory epithelial cells. Nontypeable Haemophilus influenzae (NTHI) is a Gram-negative, human-exclusive commensal bacterium of the nasopharynx and is a leading cause of opportunistic infections in the upper and lower respiratory tracts, including otitis media, sinusitis, conjunctivitis, community-acquired pneumonia, and exacerbations of chronic obstructive pulmonary disease (COPD) and of cystic fibrosis (1, 2).When a new strain of NTHI is acquired, the outcome depends on a variety of dynamic host and bacterial factors. Colonization and the transition from commensal to opportunistic pathogen require NTHI to resist host innate immune defenses, including nutrient sequestration, mucociliary clearance, antimicrobial peptides, secretory IgA1, and phagocytosis by immune cells or by epithelial cells. Bacterial counterresistance mechanisms under investigation include adhesins, antimicrobial peptide degradation, IgA1 protease, biofilm production, modification of surface-exposed lipooligosaccharide moieties, production of outer membrane vesicles (OMVs), and others (3-12). Understanding these factors will help identify targets for therapeutic intervention, as NTHI infections induce acquired immunity consisting largely of strain-specific bactericidal antibodies that afford littl...

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“…It produced non-retractable Tfp and was non-motile Wolfgang et al, 1998). MS11pilE (clone 307) was a non-piliated (DpilE1, DpilE2) strain of MS11 (Ayala et al, 2001;Merz et al, 1996). Bacteria were grown on GCB agar (Difco) with Kellogg's supplements I and II, and maintained at 37 uC, 5 % CO 2 .…”

Section: Methodsmentioning

confidence: 99%

Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex

et al. 2009

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Early in infection, Neisseria gonorrhoeae can be observed to attach to the epithelial cell surface as microcolonies and induce dramatic changes to the host cell cortex. We tested the hypothesis that type IV pili (Tfp) retraction plays a role in the ultrastructure of both the host cell cortex and the bacterial microcolony. Using serial ultrathin sectioning, transmission electron microscopy and 3D reconstruction of serial 2D images, we have obtained what we believe to be the first 3D reconstructions of the N. gonorrhoeae-host cell interface, and determined the architecture of infected cell microvilli as well as the attached microcolony. Tfp connect both wild-type (wt) and Tfp retraction-deficient bacteria with each other, and with the host cell membrane. Tfp fibres and microvilli form a lattice in the wt microcolony and at its periphery. Wt microcolonies induce microvilli formation and increases of surface area, leading to an approximately ninefold increase in the surface area of the host cell membrane at the site of attachment. In contrast, Tfp retractiondeficient microcolonies do not affect these parameters. Wt microcolonies had a symmetrical, dome-shaped structure with a circular 'footprint', while Tfp retraction-deficient microcolonies were notably less symmetrical. These findings support a major role for Tfp retraction in microvilli and microcolony architecture. They are consistent with the biophysical attributes of Tfp and the effects of Tfp retraction on epithelial cell signalling. INTRODUCTIONNeisseria gonorrhoeae (the gonococcus, or GC) remains a significant public health concern. The Gram-negative diplococcus causes a million cases of gonorrhoea annually in Western Europe and North America, and over 62 million cases worldwide (World Health Organization). Humans are the only known reservoir for GC. The exquisite tropism of GC for man and the ability of GC to establish a carrier state (Turner et al., 2002) reflect a highly evolved relationship between pathogen and host.Gonococcal attachment is promoted by type IV pili (Tfp), peritrichous fibres that are 6 nm in width and up to several micrometres in length. The Tfp filament is composed of helical polymers of pilin subunits (Craig et al., 2006;Parge et al., 1995) and minor proteins (Carbonnelle et al., 2005;Winther-Larsen et al., 2005). Tfp participate in important biological processes such as DNA uptake/genetic exchange, twitching motility, attachment, and host cell signalling (Mattick, 2002;. These activities require, or are enhanced by, the retraction of Tfp fibres (Wolfgang et al., 2000).Gonococcal Tfp retraction is an activity that requires PilT, the Tfp retraction motor subunit (Wolfgang et al., 1998). Retracting Tfp generate strong 'pull' forces, ranging from 50 picoNewtons (pN) to 1 nanoNewton (nN) (Biais et al., 2008;Opitz et al., 2009). Repeated cycles of Tfp extension, substrate attachment and Tfp retraction allow GC to crawl over surfaces and aggregate into microcolonies. Tfp retraction from bacteria in a microcolony allows the community to craw...

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The pilus-induced Ca2+ flux triggers lysosome exocytosis and increases the amount of Lamp1 accessible to Neisseria IgA1 protease

Cited by 44 publications

References 52 publications

Global Gene Expression and the Role of Sigma Factors in Neisseria gonorrhoeae in Interactions with Epithelial Cells

Global Gene Expression and the Role of Sigma Factors in Neisseria gonorrhoeae in Interactions with Epithelial Cells

Internalization and Trafficking of Nontypeable Haemophilus influenzae in Human Respiratory Epithelial Cells and Roles of IgA1 Proteases for Optimal Invasion and Persistence

Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex

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