Research Paper Volume 9, Issue 10 pp 2052—2068

PKCζ-dependent upregulation of p27kip1 contributes to oxidative stress induced retinal pigment epithelial cell multinucleation

Dinusha Rajapakse1, , Mei Chen1, , Tim M. Curtis1, , Heping Xu1, ,

  • 1 Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen’s University Belfast, Belfast, BT97 BL, UK

Received: August 7, 2017       Accepted: September 28, 2017       Published: October 9, 2017
How to Cite

Copyright: Rajapakse et al. This is an open‐access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Retinal pigment epithelial (RPE) cells increase in size and multinucleate during aging. We have shown using human and mouse cell lines that oxidised photoreceptor outer segments (oxPOS)-induced cytokinesis failure is related to RPE cell multinucleation, although the underlying mechanism remains unknown. This study investigated the role of the PKC pathway in oxPOS-induced RPE multinucleation using ARPE19 cells. oxPOS treatment promoted PKC activity and upregulated the mRNA expression of PKC α, δ, ζ, ι and μ. Inhibition of PKCα with Gӧ6976 resulted in a 33% reduction of multinucleate ARPE19 cells, whereas inhibition of PKCζ with Gӧ6983 led to a 50% reduction in multinucleate ARPE19 cells. Furthermore, oxPOS treatment induced a PKCζ-dependent upregulation of the Cdk inhibitor p27kip1, its inhibition using A2CE reduced oxPOS-induced ARPE19 multinucleation. Our results suggest that oxPOS-induced ARPE19 cytokinesis failure is, at least in part, due to the upregulation of p27kip1 through activating the PKC, particularly PKCζ pathway. Targeting the PKCζ-p27kip1 signalling axis may be a novel approach to restore RPE repair capacity during aging.


AMD: age-related macular degeneration; A2CE: alsterpaullone, 2-cyanoethyl; oxPOS: oxidised photoreceptor outer segment; PKS: protein kinase C; POS: photoreceptor outer segment; PVR: proliferative vitreoretinopathies; RPE: retinal pigment epithelium; ROS: reactive oxygen species.