Ocular surface mucins and epithelial cell surface glycoproteins

Ocular surface mucins and epithelial cell surface glycoproteins are a diverse group of high-molecular-weight glycoproteins that constitute the protective glycocalyx and the mucous layer of the tear film. These molecules are categorized into membrane-associated mucins, such as MUC1, MUC4, and MUC16, which are anchored to the apical membranes of corneal and conjunctival epithelial cells, and secreted mucins, primarily MUC5AC, which are produced by conjunctival goblet cells (Mantelli & Argüeso, 2008, PubMed: 18435583). Their primary biological functions include providing a hydrophilic interface to stabilize the tear film, lubricating the ocular surface to reduce friction during blinking, and acting as a physical and chemical barrier against pathogens and environmental insults (Gipson, 2004, PubMed: 15173041). Dysregulation or deficiency of these glycoproteins is a hallmark of dry eye disease and Sjögren's syndrome, leading to tear film instability, epithelial desiccation, and inflammation (Uchino et al., 2011, PubMed: 21940467). Pharmacological interventions, such as Rebamipide and Diquafosol, target these molecules by stimulating their expression or secretion to restore ocular surface homeostasis and improve patient symptoms (Kinoshita et al., 2013, PubMed: 22900557). Additionally, novel therapies like Varenicline nasal spray stimulate the trigeminal parasympathetic pathway to increase natural tear production, including mucins (Frampton, 2022, PubMed: 35195870). These glycoproteins are essential for maintaining the health and transparency of the cornea and conjunctiva. Therapeutic strategies often involve the use of secretagogues or mucin-mimetic agents to compensate for the loss of natural mucin production in diseased states (Watanabe, 2002, PubMed: 12114273).

Other names

Ocular mucinsTear film mucinsGlycocalyx glycoproteinsMembrane-associated mucinsSecretory mucins

Stimulation of mucin secretion via P2Y2 receptor agonism, induction of mucin gene expression (MUC1, MUC4, MUC16), nicotinic acetylcholine receptor agonism to stimulate the trigeminal parasympathetic pathway, and preservation of goblet cell density through anti-inflammatory effects.