Abstract: FR-PO699
Phagocyte-Derived Ribonuclease 3 Promotes Bacterial Clearance during Urinary Tract Infection
Session Information
- Pediatric Nephrology - 1
October 25, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pediatric Nephrology
- 1900 Pediatric Nephrology
Authors
- Cortado, Hanna H., Nationwide Children's Hospital, Columbus, Ohio, United States
- Kercsmar, Macie M., Nationwide Children's Hospital, Columbus, Ohio, United States
- Li, Birong, Nationwide Children's Hospital, Columbus, Ohio, United States
- Gupta, Sudipti, Nationwide Children's Hospital, Columbus, Ohio, United States
- Ching, Christina B., Nationwide Children's Hospital, Columbus, Ohio, United States
- Jackson, Ashley R., Nationwide Children's Hospital, Columbus, Ohio, United States
- Ruiz-Rosado, Juan de Dios, Nationwide Children's Hospital, Columbus, Ohio, United States
- Becknell, Brian, Nationwide Children's Hospital, Columbus, Ohio, United States
Background
Urinary tract infections (UTI) are common, serious bacterial infections in children, most often caused by uropathogenic Escherichia coli (UPEC), and can lead to urosepsis, acute kidney injury, and renal scarring. Identifying mechanisms of host defense against UTI is crucial in the development of innovative and effective strategies to mitigate these sequelae. The production of antimicrobial peptides (AMPs) is an important component of the innate host immune response against uropathogens. Our group is focused on identifying AMPs within the RNase A superfamily that play a role in controlling UTI. Here, we determine the contribution of human RNase3 to host UTI defense in vivo and its impact on phagocyte antimicrobial activities.
Methods
Urine RNase3 levels were measured by ELISA in girls with UTI and compared to unaffected controls. Humanized RNASE3 transgenic mice underwent transurethral inoculation of UPEC, and bacterial colony forming units (CFU) were enumerated in urinary tract organs. We utilized immunofluorescence microscopy and intracellular flow cytometry to identify cellular sources of RNase3. The bactericidal activity of RNase3 toward UPEC was investigated using recombinant RNase3 and RNASE3 transgenic phagocytes.
Results
RNase3 amino-terminal peptide exhibited dose dependent antimicrobial activity towards UPEC. RNase3 levels were elevated in urine from pediatric patients with UTI compared to healthy controls. Studies in RNASE3 transgenic mice and human tissues evince that RNase3 is expressed by neutrophils, monocytes and macrophages that infiltrate the infected kidney and bladder following UPEC exposure. RNASE3 transgenic mice are protected from ascending UPEC infection, and RNASE3 transgenic phagocytes are more adept at UPEC killing compared to non-transgenic controls.
Conclusion
Our data establish that RNase3 is an antimicrobial peptide induced during human UTI with potent bactericidal activity toward UPEC. Functionally, evidence in RNASE3 transgenic mice and phagocytes demonstrates that RNase3 effectively limits disseminated UPEC infection.