RESUMO
Colibactin is a recently characterized pro-carcinogenic genotoxin produced by pks+ Escherichia coli. We hypothesized that cystic fibrosis (CF)-associated dysfunctional mucus structure increases the vulnerability of host mucosa to colibactin-induced DNA damage. In this pilot study, we tested healthy-appearing mucosal biopsy samples obtained during screening and surveillance colonoscopies of adult CF and non-CF patients for the presence of pks+ E. coli, and we investigated the possibility of detecting a novel colibactin-specific DNA adduct that has not been yet been demonstrated in humans. While CF patients had a lower incidence of pks+ E. coli carriage (~8% vs 29%, p = 0.0015), colibactin-induced DNA adduct formation was detected, but only in CF patients and only in those who were not taking CFTR modulator medications. Moreover, the only patient found to have colon cancer during this study had CF, harbored pks+ E. coli, and had colibactin-induced DNA adducts in the mucosal samples. Larger studies with longitudinal follow-up should be done to extend these initial results and further support the development of colibactin-derived DNA adducts to stratify patients and their risk.
Assuntos
Colo , Fibrose Cística , Adutos de DNA , Escherichia coli , Mucosa Intestinal , Muco , Peptídeos , Policetídeos , Fibrose Cística/microbiologia , Fibrose Cística/metabolismo , Humanos , Policetídeos/metabolismo , Adutos de DNA/metabolismo , Adulto , Escherichia coli/genética , Escherichia coli/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Peptídeos/metabolismo , Masculino , Colo/microbiologia , Colo/patologia , Colo/metabolismo , Feminino , Projetos Piloto , Muco/metabolismo , Muco/microbiologia , Pessoa de Meia-Idade , Adulto Jovem , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologiaRESUMO
MR1T cells are a recently found class of T cells that recognize antigens presented by the major histocompatibility complex-I-related molecule MR1 in the absence of microbial infection. The nature of the self-antigens that stimulate MR1T cells remains unclear, hampering our understanding of their physiological role and therapeutic potential. By combining genetic, pharmacological, and biochemical approaches, we found that carbonyl stress and changes in nucleobase metabolism in target cells promote MR1T cell activation. Stimulatory compounds formed by carbonyl adducts of nucleobases were detected within MR1 molecules produced by tumor cells, and their abundance and antigenicity were enhanced by drugs that induce carbonyl accumulation. Our data reveal carbonyl-nucleobase adducts as MR1T cell antigens. Recognizing cells under carbonyl stress allows MR1T cells to monitor cellular metabolic changes with physiological and therapeutic implications.