# Prevention of intracellular infection in diabetic wounds by commensal Staphylococcus epidermidis

> **NIH NIH R01** · UNIVERSITY OF MIAMI SCHOOL OF MEDICINE · 2024 · $600,830

## Abstract

Abstract
Diabetic foot ulcers (DFUs) and diabetic foot infections (DFI) are one of the most challenging complications of
diabetes due to high morbidity and associated mortality and precede the majority of non-traumatic lower limb
amputations in the adult population. Diabetic foot microbiome of intact skin, prior to the onset of the ulcer, is
characterized by the low level of Staphylococcus epidermidis (SE) and high levels of Staphylococcus aureus
(SA). Persistent level of bacteria in ulcer tissue, resulting in prolonged and deregulated inflammation is one of
the leading causes of lower leg amputations in patients suffering from DFUs. To gain greater insight into
relationship between innate immune responses and wound healing outcomes, we propose to study how
commensal microorganism SE prevents intracellular accumulation of SA and accelerates the diabetic wound
healing process. The long term goal of this project is to prevent DFI by understanding the mechanism and
developing new therapeutic strategies targeting cutaneous intracellular pathogens in patients with DFUs. We
have already shown that downregulation of an innate-antimicrobial protein P-2 in keratinocytes and gamma
delta (GD) T cells results in accumulation of intracellular MRSA in DFUs, contributing to persistent unresolved
inflammation. Furthermore, loss of P-2 in murine models is associated with both, lower antimicrobial activity
and accumulation of intracellular MRSA, and impaired epithelialization. Importantly, we have shown that killing
of intracellular MRSA is enhanced in skin after exposure to SE. Based on robust preliminary data we postulate
that SE colonization modifies diabetic skin and wound environment to prevent intracellular infections by
pathogenic SA. Our hypothesis is that intracellular bacteria modify expression and function of P-2 to affect
bacterial clearance and inflammatory response, directly impacting healing in DFU. The objective of this project
is to determine mechanism by which SE prevents intracellular infections by pathogenic SA in a diabetic mouse
and human wounds. We hypothesized that SE colonization modifies wound environment in order to prevent or
resolve persistent bacterial wound infections. To test our hypothesis, we will evaluate SE-mediated induction of
P-2 in professional and non-professional phagocytes during acute diabetic and non-diabetic wound healing
process in vivo, using multiple animal and human models and samples obtained from DFU patients. We will
also identify gene expression signatures and pathways in these cells that are differentially regulated in “low
intracellular SA non-healing” vs “high intracellular SA healing” DFU (Aim 1). We will characterize SE protective
mechanisms against intracellular MRSA in diabetic wound infections (Aim 2). Our findings will provide
important new knowledge regarding the role and mechanisms by which commensal SE may prevent persistent
diabetic wound infections. Targeting intracellular bacteria niche to accele...

## Key facts

- **NIH application ID:** 10836500
- **Project number:** 5R01DK136241-02
- **Recipient organization:** UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
- **Principal Investigator:** Irena Pastar
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $600,830
- **Award type:** 5
- **Project period:** 2023-05-03 → 2027-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10836500

## Citation

> US National Institutes of Health, RePORTER application 10836500, Prevention of intracellular infection in diabetic wounds by commensal Staphylococcus epidermidis (5R01DK136241-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10836500. Licensed CC0.

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