Progress in the effects of Ca2+ signaling pathway in conjunctival goblet cells on mucin secretion in dry eye patients

Abstract:

Dry eye is a chronic ocular surface disease caused by multiple factors. It is caused by the instability of tear film and the imbalance of the microenvironment of ocular surface, and may be accompanied by ocular surface inflammation, damage, and abnormal nerve sensation. The instability of tear film is its core characteristic. Mucin is an important component of the tear film and plays a role in stabilizing the tear film. The reduction of its secretion and the change of its structure lead to the occurrence and development of dry eye. The intracellular Ca²⁺ signal is the key to controlling the secretion of water and enzymes by exocrine glands. A decrease in the Ca²⁺ signal can cause dry eye. Conjunctival goblet cells are the main cells that secrete mucin. By activating the intracellular PLC-IP3-Ca²⁺ pathway, RyRs pathway, cAMP signaling pathway, P2X receptor, BLT1 and ChemR23 receptors, cholinergic receptor, and ALX signaling pathway, the content of Ca²⁺ can be increased, and the replenishment of mucin granules can be accelerated, thereby relieving the symptoms of dry eye. The Ca²⁺ signaling pathway may be an important target for the treatment of dry eye. This article reviews the role of mucin in dry eye and the influence of the Ca²⁺ signal on the secretion of mucin by conjunctival goblet cells.