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Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
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The multifunctional human ocular melanocortin system
Chieh-Lin Stanley Wu1, Adrian V Cioanca2, Maria C Gelmi3
1School of Optometry and Vision Science, Faculty of Medicine and Health, University of New South Wales, Sydney, Australia; Save Sight Institute and Ophthalmology, The Faculty of Medicine and Health, The University of Sydney, Sydney, Australia; Department of Optometry, Asia University, Taichung, Taiwan.
Progress in Retinal and Eye Research
|May 22, 2023
Summary
The melanocortin system, involving alpha-melanocyte stimulating hormone (α-MSH), is crucial for eye immune privilege and homeostasis. Targeted melanocortin receptor peptides offer non-steroidal treatments for inflammatory eye diseases.
Area of Science:
- Ophthalmology
- Immunology
- Endocrinology
Background:
- Immune privilege in the eye is maintained by physical barriers, immune regulation, and secreted proteins like alpha-melanocyte stimulating hormone (α-MSH).
- α-MSH, secreted within ocular tissues, regulates immune responses by supporting suppressor immune cells and activating regulatory T-cells.
- The melanocortin system, comprising melanocortin receptors (MC1R-MC5R) and receptor accessory proteins (MRAPs), orchestrates various ocular functions beyond immune regulation.
Purpose of the Study:
- To review the physiological and disease-related roles of the melanocortin system in human eye tissues.
- To highlight the emerging benefits of melanocortin receptor (MCR) targeted peptides as non-steroidal alternatives for inflammatory eye conditions.
- To explore translational applications of MCR-targeted peptides in promoting ocular homeostasis.
Main Methods:
- Literature review of studies on the melanocortin system in ocular tissues.
- Analysis of the biological functions of α-MSH and its interaction with melanocortin receptors.
- Evaluation of the therapeutic potential of MCR-specific peptides for ocular inflammatory diseases.
Main Results:
- The melanocortin system is integral to maintaining corneal transparency, ocular immune privilege, retinal homeostasis, and neuroprotection.
- α-MSH and MCRs play roles in limiting lymphangiogenesis, sustaining corneal integrity, and regulating tear secretion.
- Targeted MCR peptides, unlike older ACTH-based treatments, offer reduced corticosteroid production and fewer systemic side effects.
Conclusions:
- The melanocortin system is a key regulator of ocular homeostasis and immune privilege.
- Melanocortin receptor targeted peptides represent promising non-steroidal therapeutic agents for inflammatory eye diseases like uveitis and dry eye.
- Further research into MCR-targeted peptides could lead to novel treatments for conditions such as corneal transplantation complications and diabetic retinopathy.
Keywords:
(lymph)angiogenesisAdrenocorticotropic hormone (ACTH)CytoprotectionDiabetic retinopathyDry eye diseaseInflammationMelanocortin peptides and receptorsMelanogenesisProopiomelanocortin (POMC)Uveal melanomaUveitisα-melanocyte stimulating hormone (α-MSH)More Related Videos
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