# Linking Insulin Signaling to Antimicrobial Peptide Production and the Kidney's Antibacterial Defenses

> **NIH NIH R01** · RESEARCH INST NATIONWIDE CHILDREN'S HOSP · 2021 · $345,499

## Abstract

ABSTRACT
Diabetes mellitus is a systemic disorder that increases infection susceptibility. The most common site of infection is the
urinary tract. Urinary tract infection (UTI) is more common, more severe, and has worse outcomes in people with
diabetes. To date, the mechanisms that predispose people with diabetes to UTI have not been elucidated. This project will
evaluate how insulin regulates innate immune mechanisms in the kidney’s intercalated cells. Surmounting evidence from
our research group and others suggests that intercalated cells (IC) play a critical role in antibacterial defenses against
uropathogenic E. coli (UPEC). Our research shows that insulin resistance and Type 2 diabetes mellitus increases UTI risk.
When the insulin receptor is selectively deleted in murine ICs, UPEC susceptibility significantly increases in vivo. Also,
we have demonstrated that insulin induces antimicrobial peptide (AMP) expression in primary human renal epithelial cells
via the phosphatidylinositide 3-kinase (PI3K/AKT) signaling pathway. Specifically, our data show that insulin induces
Ribonuclease 7 (RNase 7) production, the most potent AMP in the human urinary tract, to shield the urothelium from
UPEC. Together, these data provide strong support for our hypothesis that insulin signaling plays an essential role in
innate IC defenses by regulating PI3K/AKT activity and downstream AMP production. Building on these previous
studies, we propose a comprehensive analysis of insulin’s ability to regulate IC defense mechanisms. Aim 1 will evaluate
how insulin resistance and Type 2 diabetes mellitus affects IC antibacterial defenses. Aim 2 will identify how IC insulin
receptor deletion impacts AMP transcription and whether targeted PI3K/AKT activation induces AMP expression. Aim 3
will use a novel transgenic humanized mouse model to assess how insulin resistance and insulin therapy impacts the
production of RNase 7 and its antimicrobial activity in vivo. The long-term objective of this project is to improve the care
of diabetic patients with UTI by identifying novel therapeutic options. By evaluating the role of insulin signaling in host
defense, completion of these Aims can have profound influence on the health of people with diabetes as they may develop
insulin-signaling targets, like PI3K/AKT and RNase 7, as new therapeutics that prevent UTI, extending UTI treatment
options beyond the scope of antibiotics.

## Key facts

- **NIH application ID:** 10113589
- **Project number:** 5R01DK114035-04
- **Recipient organization:** RESEARCH INST NATIONWIDE CHILDREN'S HOSP
- **Principal Investigator:** John David Spencer
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $345,499
- **Award type:** 5
- **Project period:** 2018-04-03 → 2024-02-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10113589

## Citation

> US National Institutes of Health, RePORTER application 10113589, Linking Insulin Signaling to Antimicrobial Peptide Production and the Kidney's Antibacterial Defenses (5R01DK114035-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10113589. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*