# Role of Programmed Cell Death Pathways in Bacterial Keratitis

> **NIH NIH R01** · WAYNE STATE UNIVERSITY · 2024 · $433,578

## Abstract

PROJECT ABSTRACT
Diabetic patients are known to have a higher incidence of infection, with increased disease severity and an
increased rate of multi-drug resistance. In the diabetic (DM) cornea, this results in increased susceptibility to and
the rapid progression of microbial keratitis. To date, the mechanisms underlying this are unknown. To address
this critical and understudied question, Pseudomonas (P.) aeruginosa and Staphylococcus (S.) aureus keratitis
models with Streptozotocin-induced type 1 (T1) and db/db type 2 (T2) DM mice were established. In our models,
higher inocula of both P. aeruginosa and S. aureus were required to infect mouse corneas and bacterial keratitis
progressed faster in DM, compared to normoglycemia B6 mice, mimicking human diabetic infectious keratitis.
High-throughput RNA sequencing (RNA-seq), in combination with comprehensive bioinformatics, was used to
identify differentially expressed genes (DEGs) and biological processes associated with the increased
susceptibility and severity of diabetic BK. Our preliminary data show that P. aeruginosa infection resulted in many
DEGs, some of which have not been linked previously to the pathogenesis of bacterial keratitis. Gene Ontology
enrichment analysis revealed that programmed cell death (PCD) pathways, known to play a key role in
homeostasis and in the pathogeneses of many human diseases, including DM and sepsis, were altered during
P. aeruginosa infection. Our preliminary data showed that while noninflammatory apoptosis was decreased, lytic
PCDs, including caspase-8, receptor-interacting protein family of serine/threonine protein kinases (RIPK)-1 and
-3, mediated necroptosis, NETosis, a biological process to generate neutrophil extracellular traps (NETs), as
well as efferocytosis that removes cell corpses, were elevated in DM, compared to NL corneas in response to P.
aeruginosa infection. The hypothesis that DM causes lytic PCD pathways and impairs efferocytosis,
resulting in increased susceptibility and severity of BK will be tested with three specific aims:
(1) To test the
hypothesis that DM skews PCD from apoptosis to necroptosis, resulting in hyperinflammation and tissue damage.
This can be tested by assessing the levels of cleaved (activated) caspase-8 (apoptosis), phospho-RIPK1, and 3
(necroptosis), and by targeting Casp8 and RIPK1, 3 in both T1 and T2 DM mice. (2) To test the hypothesis that
DM primes PMNs for NETosis, increasing bacterial burden, and keratitis severity in B6 mouse corneas. This
can be tested by assessing the generation of Neutrophil extracellular traps containing neutrophil granule proteins
and host DNA that were modified by peptidyl arginine deiminase (PAD)-4 and nuclear neutrophil elastase and
blockade of DAD4 in T1 and T2DM mice. (3) To test the hypothesis that DM impairs efferocytosis, resulting in
secondary necrosis and tissue deterioration in bacterial infected B6 mouse corneas. This can be tested by
measuring macrophage efferocytosis of dea...

## Key facts

- **NIH application ID:** 10790434
- **Project number:** 1R01EY035785-01
- **Recipient organization:** WAYNE STATE UNIVERSITY
- **Principal Investigator:** Fu-Shin X Yu
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $433,578
- **Award type:** 1
- **Project period:** 2024-03-01 → 2029-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10790434

## Citation

> US National Institutes of Health, RePORTER application 10790434, Role of Programmed Cell Death Pathways in Bacterial Keratitis (1R01EY035785-01). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10790434. Licensed CC0.

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