Use of Zebrafish to Probe the Divergent Virulence Potentials and Toxin Requirements of Extraintestinal Pathogenic Escherichia coli

Wiles, Travis J.; Bower, Jean M.; Redd, Michael J.; Mulvey, Matthew

doi:10.1371/journal.ppat.1000697

Cited by 77 publications

(107 citation statements)

References 93 publications

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“…HlyA has also been shown to induce calcium oscillations in renal epithelial cells (51), and reports indicate a higher association of HlyA-positive UPEC with severe pyelonephritis (52,53). Previous work also elucidated a role for HlyA in repressing host cell signaling; attenuating the viability, chemotaxis, and effector functions of host phagocytes like neutrophils and macrophages (54)(55)(56)(57); and disrupting NF-κB signaling and expression of cytokine . On the other hand, HlyA can also induce an inflammation response, as shown here.…”

Section: Overproduction Of Hlya Increases Bladder Inflammasome Activamentioning

confidence: 99%

Dysregulation ofEscherichia coliα-hemolysin expression alters the course of acute and persistent urinary tract infection

Nagamatsu¹,

Hannan

Guest

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

139

160

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Urinary tract infections (UTIs) are among the most common bacterial infections, causing considerable morbidity in females. Infection is highly recurrent despite appropriate antibiotic treatment. Uropathogenic Escherichia coli (UPEC), the most common causative agent of UTIs, invades bladder epithelial cells (BECs) and develops into clonal intracellular bacterial communities (IBCs). Upon maturation, IBCs disperse, with bacteria spreading to neighboring BECs to repeat this cycle. This process allows UPEC to gain a foothold in the face of innate defense mechanisms, including micturition, epithelial exfoliation, and the influx of polymorphonuclear leukocytes. Here, we investigated the mechanism and dynamics of urothelial exfoliation in the early acute stages of infection. We show that UPEC α-hemolysin (HlyA) induces Caspase-1/Caspase-4-dependent inflammatory cell death in human urothelial cells, and we demonstrate that the response regulator (CpxR)-sensor kinase (CpxA) two-component system (CpxRA), which regulates virulence gene expression in response to environmental signals, is critical for fine-tuning HlyA cytotoxicity. Deletion of the cpxR transcriptional response regulator derepresses hlyA expression, leading to enhanced Caspase-1/Caspase-4-and NOD-like receptor family, pyrin domain containing 3-dependent inflammatory cell death in human urothelial cells. In vivo, overexpression of HlyA during acute bladder infection induces more rapid and extensive exfoliation and reduced bladder bacterial burdens. Bladder fitness is restored fully by inhibition of Caspase-1 and Caspase-11, the murine homolog of Caspase-4. Thus, we have discovered that fine-tuning of HlyA expression by the CpxRA system is critical for enhancing UPEC fitness in the urinary bladder. These results have significant implications for our understanding of how UPEC establishes persistent colonization. microbial pathogenesis | urinary tract infection | uropathogenic E. coli | persistent colonization

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Section: Overproduction Of Hlya Increases Bladder Inflammasome Activamentioning

confidence: 99%

Dysregulation ofEscherichia coliα-hemolysin expression alters the course of acute and persistent urinary tract infection

Nagamatsu¹,

Hannan

Guest

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

139

160

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“…UPEC with CNF1 promotes apoptosis and more inflammation than UPEC without CNF1 [35,36]. -Hemolysin and CNF1 were confirmed provocation of inflammation in mouse model and zebrafish infection model [37]. UPEC secrets AT toxins (Sat, Pic, and Tsh) [10].…”

Section: Toxinsmentioning

confidence: 95%

Molecular Defense Mechanisms during Urinary Tract Infection

Choi

Chang

2015

Urogenit Tract Infect

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The urinary tract is a common site of infection. The complete mechanisms of urinary tract infection (UTI) are still unknown. In general, the strategies of the uropathogenic Escherichia coli are adherence, motility, iron acquisition, toxin, and evasion of host immunity. Host immune responses play a significant part in defense of UTI. Various antimicrobial peptides (AMPs) including defensins, cathelicidin, hepcidin, ribonuclease 7, lactoferrin, lipocalin, Tamm-Horsfall protein, and secretory leukocyte proteinase inhibitor help to prevent UTI by modulation of innate and adaptive immunity. Toll-like receptors (TLRs) play an important role of microorganism identification in innate immunity. Stimulation of TLRs on the cell membrane by ligand of bacteria triggers production of inflammatory chemokines, cytokines, and AMPs. These mechanisms are an attempt to defend the urinary tract against UTI. Keywords: Urinary tract infections; Molecular biology INTRODUCTIONUrinary tract infections (UTIs) are one of the most common infections that lead to out-patient and in-patient hospital visits. About 50% of women suffer from a UTI during their lifetime [1]. About 8 million female patients are treated annually for UTI alone in the United States and UTI recurs in about 30% of those who have normal function and anatomy of urinary tract [2]. UTI comprises acute uncomplicated cystitis and acute uncomplicated pyelonephritis. Acute uncomplicated cystitis results in dysuria, frequency, or urgency in healthy and non-pregnant women [3]. The diagnosis is aided by the presence of pyuria in voided urine and positive urine culture of at least 10 3 CFU/ml [3]. Acute uncomplicated pyelonephritis results in fever, costovertebral angle tenderness and flank pain in healthy and non-pregnant women and is similar to cystitis in lower urinary tract symptoms and laboratory analyses [4]. UTIs are commonly classified as uncomplicated and complicated. Complicated UTI occurs in patients with co-morbid illness or anatomic malformations of the urinary tract that can aggravate the risk of infection or therapeutic failure [5]. Complicating factors, for example, include the presence of catheter, obstructive uropathy, pregnancy, urinary stones, diabetes, and male gender. Most of them are main causes of pathogenesis in the host. Meanwhile, bacterial factors in UTI have been studied worldwide for decades with the main focus on Escherichia coli that is the most common pathogen in community acquired UTI [6]. Eighty percent to ninety percent of acute uncomplicated cystitis or acute uncomplicated pyelonephritis correspond to E. coli and the similar explanation applies to most complicated UTIs [7]. E. coli are classified into intestinal E. coli and extraintestinal E. coli. Most in vivo and clinical studies on extraintestinal E. coli related to UTI show that the specific adaptations of uropathogenic E. coli (UPEC)

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“…The above observation may be explained by the availability of nutrients important for bacterial survival, possibly as a result of the close association of the bacteria with the urinary tract epithelium (Bahrani-Mougeot et al, 2002). In addition, the mouse model may not completely mimic the pathogenesis process of UTI in humans (Wiles et al, 2009). Therefore, we cannot exclude the possibility that the NAD auxotrophy would have an influence on the virulence of UPEC in the natural host.…”

Section: Similar Colonization Of Nad Auxotrophic and Prototrophic Dermentioning

confidence: 97%

Nicotinamide dependence of uropathogenic Escherichia coli UTI89 and application of nadB as a neutral insertion site

Bouckaert

Deboeck

et al. 2012

Microbiology

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NAD and NADP are ubiquitous in the metabolism of Escherichia coli K-12. NAD auxotrophy can be rendered by mutation in any of the three genes nadB, nadA and nadC. The nadB and nadA genes were defined as antivirulence loci in Shigella spp., as a mutation (mainly in nadB) disrupting the synthesis of quinolinate is required for virulence. Uropathogenic E. coli (UPEC) isolates from acute cystitis patients, exhibiting nicotinamide auxotrophy, were of serotype O18 : K1 : H7. E. coli UTI89, the model uropathogenic and O18 : K1 : H7 strain, requires nicotinamide or quinolinate for growth. A mutation in the nadB gene, encoding L-aspartate oxidase, was shown to be responsible for the nicotinamide requirement of UTI89. This was further confirmed by complementation of UTI89 with a recombinant plasmid harbouring the nadB gene of E. coli K-12. An Ala28Val point mutant of the recombinant plasmid failed to support the growth of UTI89 in minimal medium. This proves that the Ala28Val mutation in the NadB gene of UTI89 completely impedes de novo synthesis of nicotinamide. In spontaneous prototrophic revertants of UTI89, the nadB gene has a Val28Ala mutation. Both analyses implicate that the nicotinamide auxotrophy of UTI89 is caused by a single Ala28Val mutation in NadB. We showed that the same mutation is also present in other NAD auxotrophic E. coli O18 strains. No significant differences were observed between the virulence of isogenic NAD auxotrophic and prototrophic strains in the murine ascending urinary tract infection model. Considering these data, we applied the nadB locus as a neutral site for DNA insertions in the bacterial chromosome. We successfully restored the parental phenotype of a fimH mutant by inserting fimH, with a synthetic em7 promoter, into the nadB gene. This neutral insertion site is of significance for further research on the pathogenicity of UPEC.

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Use of Zebrafish to Probe the Divergent Virulence Potentials and Toxin Requirements of Extraintestinal Pathogenic Escherichia coli

Cited by 77 publications

References 93 publications

Dysregulation ofEscherichia coliα-hemolysin expression alters the course of acute and persistent urinary tract infection

Dysregulation ofEscherichia coliα-hemolysin expression alters the course of acute and persistent urinary tract infection

Molecular Defense Mechanisms during Urinary Tract Infection

Nicotinamide dependence of uropathogenic Escherichia coli UTI89 and application of nadB as a neutral insertion site

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