Glycocalyx in Ocular Health and Diseases

Glycocalyx is a network of proteoglycans with glycosaminoglycan side chains and is an important component of the eukaryotic cell surface. In the eyes, glycocalyx is expressed on corneal and conjunctival epithelial cells and on choroidal and retinal vascular endothelium. The ocular glycocalyx is critical for maintaining several key homeostatic functions in a healthy disease-free eye. The ocular surface glycocalyx is an important transcellular barrier to protect the eye from environmental chemicals and pathogens, while also reducing friction during blinking, and facilitating hydrophilicity. In the retina, besides the barrier functions, endothelial glycocalyx also serves the important functions of flow sensing and mechano-transduction. Several ocular pathologies such as dry eye disease, ocular surface infections, and diabetic retinopathy adversely impact ocular glycocalyx. A better understanding of the ocular glycocalyx in health and disease can open the potential of using glycocalyx or its components as biomarkers or therapeutic targets for the diagnosis or treatment of ocular diseases.

While the glycocalyx plays important roles in ocular health, our understanding of its specific functions remains limited. Recent advances in research tools, such as mass spectrometry, microscopy imaging, glycoarrays, and single-cell multi-omics, have provided valuable resources for exploring the glycocalyx’s role in ocular physiology. In this special issue, our goal is to bridge the knowledge gap surrounding the glycocalyx in the eye. We aim to better understand its functions and how they relate to ocular diseases. Our objectives include shedding light on the effects of glycocalyx alterations in conditions such as infections, dry eye disease, and diabetes; to extend our understanding of the glycocalyx’s role in angiogenesis and regulation of inflammation within the eye; and to explore its potential as a reliable source of biomarkers for diagnosing and monitoring ocular diseases. We hope that this special issue will contribute to advancing the field of ocular glycobiology and improving ocular health.

We welcome the submission of original research, reviews, and methods spanning the disciplines of cell biology, developmental biology, genetics, molecular biology, physiology, biochemistry, biophysics, immunology, or microbiology relevant to, but not limited to:
-The role of the glcocalyx/glycocalyx component in ocular health and disease
- Mechanisms/pathways by which the glycocalyx is involved in ocular health and disease
- Transcriptomic and/or other omics studies of glycocalyx in ocular diseases
- Development of novel therapeutic interventions targeting the glycocalyx in ocular diseases
While the glycocalyx is present in multiple cell types within the eye and contributes to ocular health and homeostasis, understanding of how the glycocalyx is affected by ocular disease and how it participates in/controls pathophysiology in ocular disease is lacking. Efforts to fill this knowledge gap are now made possible by recent advances in research tools, including proteomics, mass spectrometry, high-resolution imaging modalities, and innovative model systems.

Keywords: glycocalyx, ocular diseases, glycoprotein, eye, cornea, choroidal capillaries, endothelium, epithelium

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