Abstract
Purpose :
Ribonuclease (RNase) 5 is known to exert diverse intracellular mechanisms via its nuclear translocation. We investigated the effect of RNase 5 on the corneal endothelial cell (CEC) proliferation, thus the enhancement of corneal endothelial wound healing.
Methods :
Corneal endothelial wound healing with RNase 5 was evaluated in in vitro human cultured CECs and in in vivo cryo-damaged rabbit models. The alteration of localization of RNase 5 in human CECs by exogenous treatment of RNase 5 was visualized with fluorescence. Then, to reveal the mode of action of RNase 5 in CECs, (p-)Akt, (p-)p27Kip1, cyclin D1, D3 and E expressions were analyzed. The Ki-67 and 5-bromo-2'-deoxyuridine (BrdU) expressions were identified and the cell density analysis was performed to reveal the RNase 5-elicited proliferation of CECs.
Results :
RNase 5 up-regulated the survival of CECs and accelerated corneal endothelial wound healing in in vitro and in vivo models. RNase 5 treatment rapidly induced accumulation of cytoplasmic RNase 5 into the nucleus and activated PI3-kinase/Akt pathway in human CECs. Moreover, inhibition of nuclear translocation of RNase 5 reversed RNase 5-induced Akt activation. RNase 5 suppressed p27 and up-regulated cyclin D1, D3 and E by activating PI3-kinase/Akt in CECs to initiate cell cycle progression. Furthermore, RNase 5 treatment increased Ki-67-expressing and BrdU-incorporated proliferating CECs and up-regulated the growth of human cultured CECs.
Conclusions :
RNase 5 facilitates mitosis-driven corneal endothelial wound healing via PI3-kinase/Akt activation in CECs. RNase 5 may provide a mechanism to restore the injured corneal endothelium and is thus a useful target for therapeutic exploitation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.