Antimicrobial peptides in human corneal tissue of patients with fungal keratitis
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Imran Mohammed1, Debasmita Mohanty2, Dalia G Said1,3
1Academic Ophthalmology, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham United Kingdom.
Background:
Fungal keratitis (FK) is the leading cause of unilateral blindness in the developing world. Antimicrobial peptides (AMPs) have been shown to play an important role on human ocular surface (OS) during bacterial, viral and protozoan infections. In this study, our aim was to profile a spectrum of AMPs in corneal tissue from patients with FK during the active pase of infection and after healing.
Methods:
OS samples were collected from patients at presentation by impression cytology and scraping. Corneal button specimens were collected from patients undergoing therapeutic penetrating keratoplasty for management of severe FK or healed keratitis. Gene expression of human beta-defensin (HBD)-1, -2, -3 and -9, S100A7, and LL-37 was determined by quantitative real-time PCR.
Results:
Messenger RNA expression (mRNA) for all AMPs was shown to be significantly upregulated in FK samples. The levels of HBD-1 and -2 mRNA were found to be elevated in 18/20 FK samples. Whereas mRNA for HBD-3 and S100A7 was upregulated in 11/20 and HBD9 was increased in 15/20 FK samples. LL-37 mRNA showed moderate upregulation in 7/20 FK samples compared with controls. In healed scar samples, mRNA of all AMPs was found to be low and matching the levels in controls.
Conclusion:
AMP expression is a consistent feature of FK, but not all AMPs are equally expressed. HBD-1 and -2 are most consistently expressed and LL-37 the least, suggesting some specificity of AMP expression related to FK. These results will help to identify HBD sequence templates for designing FK-specific peptides to test for therapeutic potential.
Insights
Antimicrobial peptides (AMPs), including human beta-defensins (HBDs), are upregulated in fungal keratitis (FK). HBD-1 and HBD-2 show the most consistent expression, offering potential for FK-specific peptide therapeutics.
Area of Science:
- Ophthalmology
- Immunology
- Microbiology
Background:
- Fungal keratitis (FK) is a leading cause of unilateral blindness in developing nations.
- Antimicrobial peptides (AMPs) are crucial for ocular surface defense against various pathogens.
- This study investigates AMP profiles in corneal tissue during active FK and after healing.
Purpose of the Study:
- To profile the expression of specific AMPs in corneal tissue from FK patients.
- To compare AMP expression during active infection versus healed stages.
- To identify potential therapeutic targets for FK.
Main Methods:
- Ocular surface samples collected via cytology and scraping.
- Corneal buttons from therapeutic keratoplasty used for severe/healed FK.
- Quantitative real-time PCR used to measure gene expression of HBD-1, -2, -3, -9, S100A7, and LL-37.
Main Results:
- All investigated AMPs showed significant messenger RNA (mRNA) upregulation in active FK samples.
- HBD-1 and HBD-2 mRNA were elevated in 18/20 FK samples.
- LL-37 mRNA showed moderate upregulation in 7/20 samples, with lower expression in healed tissues.
Conclusions:
- AMP expression is a consistent characteristic of active fungal keratitis.
- HBD-1 and HBD-2 exhibit the most consistent upregulation, suggesting specificity.
- Findings may guide the development of FK-specific peptide-based therapies.
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