Unoprostone isopropyl rescues retinal progenitor cells from apoptosis in vitro.
OBJECTIVE
Unoprostone isopropyl is an ocular hypotensive that was originally produced as a prostaglandin F2alpha analogue and is eventually recognized as a synthetic docosanoid. The compound is recently suggested to have potent neuroprotective ability in the retina. The purpose of this study is to test whether and how the biologically active metabolites of unoprostone isopropyl rescue retinal neuro-glial progenitor cells from apoptosis.


METHODS
R28 cells were deprived of serum for 24 hr with or without varying concentrations of unoprostone metabolite M1 or M2 or vehicle in the presence or absence of specific inhibitors against several types of signal transduction proteins. Immunocytochemistry against activated caspase-3 with Hoechst nuclear staining was performed.


RESULTS
Up to 15%of R28 cells became pyknotic and activated caspase-3 immunoreactive after 24-hr serum withdrawal. M1, but not M2, significantly reduced apoptotic cells in a dose-dependent fashion with a maximal effect at 100 microM (p < .0001). LY294002, the phosphatidylinositol 3-OH kinase (PI3K) inhibitor, and KT5823, the protein kinase G (PKG) inhibitor, reversed the antiapoptotic effect of M1.


CONCLUSIONS
The unoprostone metabolite M1 protects retinal neuro-glial progenitor R28 cells from apoptosis induced by serum deprivation via the PI3K and PKG pathways.
Mukuno
Hirokazu
H
Department of Organ Therapeutics, Division of Ophthalmology, Kobe University Graduate School of Medicine, Chuo-Ku, Kobe, Japan.
Nakamura
Makoto
M
Kanamori
Akiyasu
A
Nagai
Azusa
A
Negi
Akira
A
Seigel
Gail
G
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002227:Carbazoles / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019610:Cytoprotection / Q000187:drug effects; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D007211:Indoles / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051381:Rats; D012160:Retina / Q000166:cytology* / Q000201:enzymology; D013234:Stem Cells / Q000166:cytology* / Q000201:enzymology
D002227:Carbazoles; D053148:Caspase 3; D020169:Caspases; D002867:Chromones; D017869:Cyclic GMP-Dependent Protein Kinases; D015237:Dinoprost; D004791:Enzyme Inhibitors; D007211:Indoles; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; C073601:KT 5823; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C072630:isopropyl unoprostone; C505410:Casp3 protein, rat