Antimicrobial peptides (AMPs) such as defensins and cathelicidin are multifunctional molecules that kill invading pathogens and modulate mammalian cell activities including proliferation, migration and cytokine production thus helping to regulate immune responses and wound healing. Recent studies have established roles for AMPs in defending the ocular surface from bacterial infection (keratitis). A logical progression to this to further our understanding of AMP actions at the ocular surface is to address the role of AMPs in keratitis caused by fungal pathogens. Fungal keratitis is a vision threatening disease, which is increasing in incidence (including a world-wide epidemic in 2004-2006), current treatments are only moderately effective and outcomes are typically more devastating than with bacterial corneal disease. Many AMPs have potent antifungal activity in vitro so likely act in innate defense against fungal pathogens and have potential as therapeutics. There have been few reports on the role for AMPs in defense against fungal keratitis thus more in depth study encompassing multiple fungal pathogens is needed to delineate their involvement and identify ways this can be exploited to prevent/treat infection. The following hypothesis will be tested: AMPs are required for ocular surface innate defense against fungal infection. This will be addressed by three specific aims.
In specific aim 1, modulation of human corneal epithelial AMP expression in response to common ocular fungi will be investigated in vitro and participation of specific pattern recognition receptors elucidated.
In specific aim 2, the antimicrobial activity of AMPs in solution and tethered to surfaces against common ocular fungi will be determined, and the influence of tear components on this activity investigated. These two aims will be informative regarding which endogenously expressed AMPs are active at the human ocular surface in vivo.
The final aim will utilize mice deficient in specific AMPs (either genetic knockouts or siRNA knockdown) to establish a role for AMPs in vivo in a model of experimental fungal keratitis. Also in specific aim 3, the potential of AMP-tethered liposomes as novel topical antifungal agents will be addressed. These studies will provide important information regarding normal host defense mechanisms against fungal pathogens and may identify novel antifungal agents for preventing and treating fungal keratitis.

Public Health Relevance

Fungal keratitis is a vision threatening disease, which is increasing in incidence (including a world-wide epidemic in 2004-2006), current treatments are only moderately effective and outcomes are typically worse than with bacterial corneal disease. This proposal addresses the role of antimicrobial peptides in defending the ocular surface against fungal pathogens and their potential as novel, topical antifungal agents.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
3R01EY013175-08A1S1
Application #
8536032
Study Section
Special Emphasis Panel (ZRG1-BDCN-C (02))
Program Officer
Mckie, George Ann
Project Start
2000-07-01
Project End
2017-04-30
Budget Start
2012-05-01
Budget End
2013-04-30
Support Year
8
Fiscal Year
2012
Total Cost
$311,381
Indirect Cost
$90,224
Name
University of Houston
Department
Type
Schools of Optometry/Ophthalmol
DUNS #
036837920
City
Houston
State
TX
Country
United States
Zip Code
77204
Kolar, Satya Sree; Baidouri, Hasna; Mangoni, Maria Luisa et al. (2017) Methods for In Vivo/Ex Vivo Analysis of Antimicrobial Peptides in Bacterial Keratitis: siRNA Knockdown, Colony Counts, Myeloperoxidase, Immunostaining, and RT-PCR Assays. Methods Mol Biol 1548:411-425
Qin, Guoting; Zhu, Zhiling; Li, Siheng et al. (2017) Development of ciprofloxacin-loaded contact lenses using fluorous chemistry. Biomaterials 124:55-64
Kolar, Satya Sree; Baidouri, Hasna; McDermott, Alison M (2017) Role of Pattern Recognition Receptors in the Modulation of Antimicrobial Peptide Expression in the Corneal Epithelial Innate Response to F. solani. Invest Ophthalmol Vis Sci 58:2463-2472
Cappiello, Floriana; Casciaro, Bruno; Kolar, Satya Sree et al. (2017) Methods for In Vitro Analysis of Antimicrobial Activity and Toxicity of Anti-keratitis Peptides: Bacterial Viability in Tears, MTT, and TNF-? Release Assays. Methods Mol Biol 1548:395-409
Li, Siheng; Wang, Lin; Yu, Fei et al. (2017) Copper-Catalyzed Click Reaction on/in Live Cells. Chem Sci 8:2107-2114
Zhu, Zhiling; Chen, Haoqing; Li, Siheng et al. (2017) Tripodal Amine Ligands for Accelerating Cu-Catalyzed Azide-Alkyne Cycloaddition: Efficiency and Stability against Oxidation and Dissociation. Catal Sci Technol 7:2474-2485
Reins, Rose Y; Hanlon, Samuel D; Magadi, Sri et al. (2016) Effects of Topically Applied Vitamin D during Corneal Wound Healing. PLoS One 11:e0152889
Mangoni, Maria Luisa; McDermott, Alison M; Zasloff, Michael (2016) Antimicrobial peptides and wound healing: biological and therapeutic considerations. Exp Dermatol 25:167-73
Li, Siheng; Cai, Honghao; He, Jilin et al. (2016) Extent of the Oxidative Side Reactions to Peptides and Proteins During the CuAAC Reaction. Bioconjug Chem 27:2315-2322
Kolar, Satya Sree N; Luca, Vincenzo; Baidouri, Hasna et al. (2015) Esculentin-1a(1-21)NH2: a frog skin-derived peptide for microbial keratitis. Cell Mol Life Sci 72:617-627

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