title: Latanoprost rescues retinal neuro-glial cells from apoptosis by inhibiting caspase-3, which is mediated by p44/p42 mitogen-activated protein kinase.
abstract: The purpose of this study was to investigate whether latanoprost, a prostaglandin F2alpha analogue, has a direct anti-apoptotic effect both in retinal neuro-glial cells in culture and in diabetic retina. R28 cells, immortalized retinal neuroglial progenitor cells, were induced apoptosis by 24h serum deprivation. Serum withdrawal made up to 15% of R28 cells pyknotic and activated caspase-3 immunoreactive, and latanoprost acid suppressed apoptosis with dose dependency at an optimum concentration of 1.0 microM (P<0.001). UO126, a mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase kinase (MEK) 1 and 2 inhibitor reversed this effect. Streptozotocin induced one- or three-month diabetic rats received balanced-salt-solution (BSS) in the left eye and latanoprost eye drops in the right for 5 days. Retinal wholemount was subjected to terminal dUTP nick end labeling (TUNEL) staining, whereas eyeballs were enucleated for cleaved caspase-3 immunofluorescence. Retinal homogenates were probed for phospho- or total p44/p42 MAPK and Akt. One- and three-month diabetic retina had 30.2+/-15.3 and 23.6+/-9.0 TUNEL positive cells per 0.5 cm(2), respectively, whereas control retina had few TUNEL positive cells. Latanoprost instillation significantly reduced these cells (10.0+/-3.1 and 11.3+/-3.1 cells per 0.5 cm(2) for 1M and 3M, respectively, P<0.01), whereas BSS did not. Latanoprost also significantly reduced cleaved caspase-3 immunoreactive cells in ganglion cell and inner nuclear layers (P<0.05). Latanoprost increased phosphorylated to total protein ratio of p44/p42 MAPK (P<0.05), but not of Akt. Taken together, the present findings suggest that latanoprost rescues retinal neurons and/or glial cells from apoptosis, which is probably mediated by p44/p42 MAPK through caspase-3 inhibition.
authors.affiliation: Division of Ophthalmology, Department of Organs Therapeutics, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakamura
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Mukuno
authors.forename: Akiyasu
authors.initials: A
authors.lastname: Kanamori
authors.forename: Gail M
authors.initials: GM
authors.lastname: Seigel
authors.forename: Akira
authors.initials: A
authors.lastname: Negi
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D061945:Caspase Inhibitors; D002460:Cell Line; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D000077338:Latanoprost; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009457:Neuroglia / Q000187:drug effects* / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009883:Ophthalmic Solutions / Q000494:pharmacology; D011461:Prostaglandins F, Synthetic / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000166:cytology / Q000187:drug effects*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology; D013234:Stem Cells / Q000187:drug effects / Q000502:physiology
chemical_list: D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost; D048049:Extracellular Signal-Regulated MAP Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3