Preferential Expression Of Periostin In Conjunctival Tissue And Its Roles For Chronic Allergic Conjunctivitis

Abstract

Purpose: : To investigate potential roles of periostin (POSTN), an extracellular matrix preferentially expressed in Th2-skewed condition, for the conjunctival inflammation.

Methods: : POSTN immunohistochemical staining was carried out using giant papillae tissue obtained from AKC/VKC patients. Real-time PCR analysis was performed to compare POSTN mRNA expression between the giant papillae tissue and conjunctivochalasis tissue. Ultrastructural analysis was carried out for corneal as well as conjunctival tissue for C57BL6 POSTN knockout (KO) mouse and wild type control mice. POSTN expression was evaluated in mouse conjunctivitis model using papain-soaked contact lenses. Cultured human conjunctival epithelial cells and fibroblasts were stimulated with recombinant IL-13 (20ng/ml) and POSTN mRNA expression was analyzed by real-time PCR.

Results: : Intense accumulation of POSTN protein was observed beneath the epithelium of conjunctivae in giant papillae tissue. Only faint POSTN expression around vascular wall was observed in conjunctivochalasis tissue. Significantly higher POSTN mRNA expression was observed in the giant papillae tissue. No gross morphological abnormalities in cornea/conjunctival tissue were found in POSTN null mice. Papain induced experimental conjunctivitis models showed preferential POSTN expression in subconjunctival tissue but not in corneal tissue. Both conjuntival epithelial cells and fibroblasts showed POSTN mRNA upregulation by IL-13 stimulation.

Conclusions: : Preferential expression of POSTN in conjunctival tissue was observed in ocular surface. Th2-skewed condition induces POSTN expression by conjunctival fibroblasts and conjunctival epithelial cells.

Keywords: conjunctiva • extracellular matrix • inflammation