Ocular mucins in dry eye disease

Abstract

Dry eye disease is a common and multifactorial disease with a high prevalence worldwide. Water loss, reduced expression of glycocalyx mucins, and loss of goblet cells secreting gel-forming mucins are hallmarks of dry eye disease. Mucins are large and complex heavily glycosylated proteins. Their organization in the tear film remains unclear, but they play a key role to protect and maintain integrity of the ocular surface. Mice have been extremely valuable mammalian models with which to study ocular physiology and disease, and to evaluate eye therapies. Genetically modified mice and spontaneously occurring mutants with eye defects have proven to be powerful tools for the pharmaceutical industry, clinicians, and basic researchers investigating dry eye disease. However, ocular mucins remain relatively under-studied and inadequately characterized. This review aims to summarize current knowledge about mucin production at the ocular surface in healthy individuals and in dry eye disease, and to compile an overview of mouse models available for the study of mucins in dry eye disease.

An Evaluation of the Physicochemical Properties of Preservative-Free 0.005% (w/v) Latanoprost Ophthalmic Solutions, and the Impact on In Vitro Human Conjunctival Goblet Cell Survival

“…Keeping goblet cells unharmed and unstressed is essential for maintaining a stable tear film for a healthy ocular surface [ 9 , 10 ]. Diluted PF 0.005% latanoprost eye drops showed no negative effects on either cell survival or mucin release after treatment, according to the LDH assay, MTT assay, and immunohistochemical staining.…”

“…Mucin is produced by the conjunctival goblet cells. Goblet cells are essential for obtaining a stable tear film, as well as protecting and lubricating the ocular surface [ 8 , 9 , 10 ].…”

Why Chain Length of Hyaluronan in Eye Drops Matters

“…The glycocalyx mainly consists of membrane bound mucins. It is covered by a mucoaqueous tear layer with lubricating properties predominantly due to dissolved gel-forming mucin MUC5AC secreted by conjunctival goblet cells [21][22][23][24][25][26][27][28][29]. The glycoprotein MUC5AC consists of a long protein molecule with oligosaccharide side chains linked by O-glycosylation to the protein backbone [23,30].…”

Characterisation of Gel-Forming Mucins Produced In Vivo and In Ex Vivo Conjunctival Explant Cultures

“…Structurally, mucins are composed of a polypeptide backbone containing threonine- and serine-enriched repeat domains that are used as anchor points for O-glycosylation. The sugar side chains are, in turn, responsible for the specific bottle brush structure [ 10 , 15 ]. Gel-forming mucins not only interact with one another but also with trefoil factors.…”