Abstract
Purpose :
FGF2 induces endothelial-mesenchymal transition (EnMT) that leads to fibrosis through ZEB1 in ex vivo human corneal endothelium (CE). This led us to investigate downstream targets of FGF2 signaling in mouse CE in vivo.
Methods :
Corneal endothelium in anesthetized mice was surgically injured in vivo under direct visualization. Expression of Fgf2, Snai1, Zeb1, Col1a1, Col1a2, Fn1, Vim, Cdk2, Ccne1 and Cdh1 were analyzed by semi-quantitative RT-PCR in ex vivo and in vivo mouse CE. Knockdown of FGF2 was done using siRNA transfection. Cell proliferation assay in ex vivo and in vivo mouse CE was performed using anti-phospho-histone H3 immunostaining. Col8a2 and Keratocan were used as marker for corneal endothelium and epithelium/stroma respectively and β-actin was used as a loading control.
Results :
FGF2 treatment induced expression of EMT-related genes including Snai1, and Zeb1 in mouse ex vivo CE. This led to increased expression of Col1a1, Col1a2, Fn1, and Vim and suppression of Cdh1 in a time-dependent manner. IL-1β dependent expression of Fgf2, Snai1, Zeb1, Col1a1, Col1a2, Fn1, Vim, Cdk2, and Ccne1 were completely abolished by FGF2 siRNA knockdown in mouse CE ex vivo. Surgical injury induced Fgf2 expression in in vivo mouse CE. Injury-dependent expression of Fgf2, Snai1, Zeb1, Col1a1, Col1a2, Fn1, Vim, Cdk2, and Ccne1 were inhibited by siRNA knockdown of FGF2 in mouse CE in vivo. Moreover, siRNA knockdown of FGF2 inhibited injury-dependent suppression of Cdh1 expression. Immunostaining of mouse ex vivo CE with anti-phospho-histone H3 antibody further showed that FGF2 is a key factor for induction of cell proliferation.
Conclusions :
These findings suggest that FGF2 induced by IL-1β in mouse CE ex vivo and in vivo promotes expression of both fibrosis- and proliferation-related genes, such as Snai1, Zeb1, Col1a1, Col1a2, Fn1, Vim, Cdk2, and Ccne1.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.