Chronic inflammation induces abnormal differentiation of corneal epithelial stem cells.

Abstract

Purpose : To investigate effect of chronic inflammation on the fate of corneal limbal stem cells.

Methods : We established a chronic corneal inflammation rat model using improved corneal suture method. Corneal neovascularization, inflammation, and epithelial status were observed under slit-lamp microscope. The eyeball and corneal epithelium were collected at 3, 7, 14, 28 days and evaluated with inflammatory markers, cytokeratin markers, stem cell markers, and signaling pathway related molecules by immunofluorescence, immunohistochemistry or/and RT-qPCR. Clone culture was performed to demonstrate proliferation potential of limbal stem cells.

Results : Improved corneal suture induced corneal neovascularization, stromal inflammation, and diffuse epithelial defect in rats. K12 and Pax6 expression was dramatically reduced in the corneal epithelium, while K10 and Sprr1b was upregulated in rat cornea after suturing. The cloning forming efficiency (CFE) was decreased in rat cornea with suture, and K14, p63, ABCG2 and wnt7a expression was also decreased. P38 MAPK signaling pathway was activated after suture and could be reversed by administration of 0.02% fluorometholone and p38 inhibitor. In corneal epithelium clone culture, p38 inhibitor could promote the expression of Ki67, K14, p63, ABCG2 and wnt7a, and downregulate the expression of K12.

Conclusions : Chronic inflammation induces abnormal differentiation of limbal stem cells through activation of P38 MAPK signaling pathway. Inhibition of p38 MAPK could promote the self-renewal of corneal limbal stem cells and inhibit abnormal differentiation.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.