Ma, GaoenDuan, YajianHuang, XionggaoQian, Cynthia X.Chee, YewlinMukai, ShizuoCui, JingSamad, ArifMatsubara, Joanne AikoKazlauskas, AndriusD'Amore, PatriciaGu, ShuyanLei, Hetian2017-02-182016Ma, G., Y. Duan, X. Huang, C. X. Qian, Y. Chee, S. Mukai, J. Cui, et al. 2016. “Prevention of Proliferative Vitreoretinopathy by Suppression of Phosphatidylinositol 5-Phosphate 4-Kinases.” Investigative Ophthalmology & Visual Science 57 (8): 3935-3943. doi:10.1167/iovs.16-19405. http://dx.doi.org/10.1167/iovs.16-19405.0146-0404http://nrs.harvard.edu/urn-3:HUL.InstRepos:30371046Purpose Previous studies have shown that vitreous stimulates degradation of the tumor suppressor protein p53 and that knockdown of phosphatidylinositol 5-phosphate 4-kinases (PI5P4Kα and -β) abrogates proliferation of p53-deficient cells. The purpose of this study was to determine whether vitreous stimulated expression of PI5P4Kα and -β and whether suppression of PI5P4Kα and -β would inhibit vitreous-induced cellular responses and experimental proliferative vitreoretinopathy (PVR). Methods: PI5P4Kα and -β encoded by PIP4K2A and 2B, respectively, in human ARPE-19 cells were knocked down by stably expressing short hairpin (sh)RNA directed at human PIP4K2A and -2B. In addition, we rescued expression of PI5P4Kα and -β by re-expressing mouse PIP4K2A and -2B in the PI5P4Kα and -β knocked-down ARPE-19 cells. Expression of PI5P4Kα and -β was determined by Western blot and immunofluorescence. The following cellular responses were monitored: cell proliferation, survival, migration, and contraction. Moreover, the cell potential of inducing PVR was examined in a rabbit model of PVR effected by intravitreal cell injection. Results: We found that vitreous enhanced expression of PI5P4Kα and -β in RPE cells and that knocking down PI5P4Kα and -β abrogated vitreous-stimulated cell proliferation, survival, migration, and contraction. Re-expression of mouse PIP4Kα and -β in the human PI5P4Kα and -β knocked-down cells recovered the loss of vitreous-induced cell contraction. Importantly, suppression of PI5P4Kα and -β abrogated the pathogenesis of PVR induced by intravitreal cell injection in rabbits. Moreover, we revealed that expression of PI5P4Kα and -β was abundant in epiretinal membranes from PVR grade C patients. Conclusions: The findings from this study indicate that PI5P4Kα and -β could be novel therapeutic targets for the treatment of PVR.en-USproliferative vitreoretinopathyPI5P4KsvitreousJournal Article2017-02-1810.1167/iovs.16-19405