Corneal and conjunctival epithelial cell calcium signaling machinery

The corneal and conjunctival epithelial cell calcium signaling machinery is a complex network of proteins responsible for maintaining ocular surface homeostasis through the regulation of intracellular calcium levels. This system includes various G protein-coupled receptors (GPCRs), such as the P2Y2 receptor, and multiple transient receptor potential (TRP) channels, including TRPV1, TRPV4, and TRPM8, which act as sensors for mechanical, thermal, and chemical stimuli (Reinach et al., 2011). Additionally, store-operated calcium entry (SOCE) mediated by Orai1 and STIM1 proteins plays a vital role in replenishing intracellular calcium stores and sustaining long-term signaling (Li et al., 2019). In the conjunctiva, this machinery is essential for the regulated secretion of mucins from goblet cells, which lubricate and protect the ocular surface (Dartt, 2009). In the cornea, calcium signaling coordinates epithelial cell proliferation, migration, and wound healing in response to injury (Yang et al., 2013). Dysregulation of this machinery is a key factor in the pathogenesis of dry eye disease, where abnormal calcium flux contributes to chronic inflammation and epithelial barrier breakdown. Therapeutic interventions often target specific components of this system; for example, diquafosol acts as a P2Y2 receptor agonist to increase calcium-dependent mucin and fluid secretion, while TRPM8 agonists are being developed to restore tear film stability and provide cooling relief.

Other names

Ocular surface calcium signaling systemCorneal epithelial Ca2+ signaling pathwayConjunctival epithelial Ca2+ signaling network

The machinery is modulated via several mechanisms: agonism of P2Y2 receptors increases intracellular calcium to trigger mucin and aqueous secretion; activation of TRPM8 channels promotes tear production and provides symptomatic relief; and inhibition of downstream calcineurin pathways reduces inflammatory cytokine production.