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Abstract: TH-PO113

The NADPH Oxidase (NOX2) Is Required to Control Urinary Tract Infections

Session Information

  • AKI: Mechanisms - I
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Ruiz-Rosado, Juan de Dios, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Cotzomi Ortega, Israel, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Han, Rachel, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Ballash, Gregory, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Sanchez-Zamora, Yuriko I., Nationwide Children's Hospital, Columbus, Ohio, United States
  • Cortado, Hanna H., Nationwide Children's Hospital, Columbus, Ohio, United States
  • Li, Birong, Nationwide Children's Hospital, Columbus, Ohio, United States
  • Becknell, Brian, Nationwide Children's Hospital, Columbus, Ohio, United States
Background

Urinary tract infections (UTIs) account for 7 million office visits and $1.6 billion dollars in health care spending annually in the United States. Uropathogenic Escherichia coli (UPEC) is the primary etiological pathogen causing over 80% of UTI. Currently, there is a critical need for innovative and effective strategies to treat UTI.
The NADPH oxidase complex 2 (NOX2) is one of the major sources of reactive oxygen species (ROS) in immune phagocytes and has a central role in the antimicrobial response against many bacterial and fungal infections, but its role during UTIs remains unknown. In this study, we elucidated the role of NOX2 during experimental UTI.

Methods

Female wild-type (WT) C57BL/6 mice, NOX2 knockout (NOX2 KO) mice, and WT mice treated with a NOX2 inhibitor (GSK) were transurethrally infected with UPEC (CFT073 strain). NOX2 protein expression was analyzed by Western blotting. Cellular sources of NOX2 were identified by immunofluorescence. The bacterial burden (UPEC) in the urinary tract was measured by enumerating colony forming units (CFU). Histopathological analysis of the infected bladder was conducted using the Hopkins score. Bone marrow Neutrophils from uninfected WT, NOX2 KO mice or peripheral blood neutrophils from healthy human donors were infected with UPEC in vitro. Neutrophil ROS production was determined using the Amplex Red kit.

Results

Knockdown or pharmaceutical inhibition of NOX2 in mice led to an increased bacterial burden in the bladder and kidney during UPEC-induced UTI. The increased susceptibility in infected NOX2 KO mice was associated with augmented bladder pathology, characterized by mucosal lesions and lamina propial edema, compared to infected WT mice. NOX2 expression significantly correlated with bacterial burden in the bladder from infected WT mice. Immunofluorescence microscopy localized NOX2 primarily in infiltrating neutrophils in the infected urinary tract. NOX2 KO neutrophils exhibited impaired extracellular ROS production and increased intracellular bacteria compared to WT neutrophils following UPEC infection in vitro. Similar effects occurred in primary human neutrophils following chemical inhibition of NOX2 in vitro.

Conclusion

NOX2-derived ROS serves a critical antimicrobial role during experimental UTI.

Funding

  • NIDDK Support