UropathogenicE. coliinduces DNA damage in the bladder

Abstract

15Urinary tract infections (UTIs) are among the most common outpatient infections, with a 16 lifetime incidence of around 60% in women. We analysed urine samples from 223 patients with 17 community-acquired UTIs and report the presence of a metabolite released during the synthesis 18 of colibactin, a bacterial genotoxin, in 50 of the samples examined. Uropathogenic Escherichia 19 coli strains isolated from these patients, as well as the archetypal E. coli strain UTI89, were 20 found to produce colibactin. In a murine model of UTI, the machinery producing colibactin was 21 expressed during the early hours of the infection, when intracellular bacterial communities 22 form. We observed extensive DNA damage both in umbrella and bladder progenitor cells. To 23 the best of our knowledge this is the first report of colibactin production in UTIs in humans and 24 its genotoxicity in bladder cells. This bacterial genotoxin, which is increasingly suspected to 25 promote colorectal cancer, should also be scrutinised in the context of bladder cancer. 26 27 28 29Urinary tract infections (UTIs) are one of the most common bacterial infections, affecting 30 approximately 150 million individuals each year 1 . UTIs occur most frequently in women, with 31 more than 60% of females diagnosed with a UTI during their lifetime 2 . The severity of these 32 infections ranges from asymptomatic bacteriuria and cystitis, i.e. infections localised to the 33 bladder, to urosepsis, which can be fatal. Recurrences are very frequent, since approximately 34 30% of women experience a new UTI episode after resolution of the initial infection 2 . In 35 addition to their consequences in terms of morbidity, mortality and associated economic and 36 societal losses, UTIs are also a major reason for antibiotic treatments and thus strongly 37 contribute to the global issue of antibiotic resistance. Escherichia coli strains, termed 38 uropathogenic E. coli (UPEC) cause approximately 80% of all UTIs. These strains belong 39 mainly to phylogroup B2, which is increasingly present in the intestinal microbiota, the 40 reservoir of UPEC 3,4 . UPEC strains produce a large number of virulence factors 5-7 . In 41 particular, several toxins have long been associated with UPEC pathogenicity, such as α-42 hemolysin and CNF1 toxins 8,9 . More recently, a large proportion of UPEC strains which carry 43 pks pathogenicity island encoding the genotoxin colibactin have been described 10-13 . 44The pks pathogenicity island, composed of clbA-S genes, encodes a polyketide-non-ribosomal 45 -peptide (PK-NRP) biosynthesis machinery 14 . Colibactin is first synthesised as an inactive 46 prodrug by the sequential interventions of Clb enzymes. ClbP peptidase subsequently cleaves 47 the C14-Asparagine (C14-Asn) motif thereby releasing the mature, active form of colibactin 48 with its twin warheads (Fig. 1a) 15-17 . The genotoxin alkylates adenine residues on both strands 49 of DNA, producing DNA interstrand cross-links 18-20 . These highly toxic DNA lesions initiate 50 a DNA damage re...

Iron regulates contrasting toxicity of uropathogenic Eschericia coli in macrophages and epithelial cells

“…Therefore, the different conditions within the vacuoles of macrophages and BECs likely differentially induced expression of other toxins that triggered macrophage death. One good candidate toxin for this is colibactin, a genotoxic protein that was recently found in ∼25% of UPEC strains [27] and its expression is upregulated at low iron concentrations [26]. Indeed, our data also show an increased and decreased transcription in ST95 of clbN (the gene coding for colibactin) in Fe 3+ depleted and enriched conditions, respectively.…”

“…Indeed, the expression of clbN and senB also increased in iron depleted conditions. Also, high growth rates of UPEC in low-iron urine of UTI patients has been reported [18] along with evidence of colibactin production by UPEC strains [27]. The other two UPEC strains ST131 and ST1981 also carry both Fe 2+ and Fe 3+ importers, and thus might be expected to also grow better at low iron concentrations.…”

The therapeutic potential of D-Serine in reducing expression of the cytopathic genotoxin colibactin

“…Such a treatment would particularly benefit high-risk patients, such as individuals with IBD, where the prevalence of E. coli belonging to the B2 phylogroup is high and the incidence of developing CRC is significantly greater [67,68]. While our results indicate promising potential for D-Serine as a therapeutic, it should be noted that colibactin has been detected in urine (an environment rich in D-Serine [9]) from individuals with pks+ urinary tract infections [69]. In the same study, colibactin-induced DNA damage was observed in a murine model of cystitis.…”

Enhancing a multipurpose artificial urine for culture and gene expression studies of uropathogenicEscherichia colistrains

“…These genes (pic and sat, respectively) are similarly expressed in both EnAU and in PHU. The colibactin genotoxin is expressed during UTI in humans, and is associated with DNA damage in the urothelial cells in a mouse model of UTI (Chagneau et al, 2021). 17 CFT073 clb genes and 15 UTI89 clb genes, which encode colibactin, were similarly expressed in EnAU and pooled human urine.…”