Nakanishi Y, Nakamura M, Mukuno H, Kanamori A, Seigel GM, Negi A. Latanoprost rescues retinal neuro-glial cells from apoptosis by inhibiting caspase-3, which is mediated by p44/p42 mitogen-activated protein kinase.
Exp Eye Res 2006;
83:1108-17. [PMID:
16839545 DOI:
10.1016/j.exer.2006.05.018]
[Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2005] [Revised: 05/16/2006] [Accepted: 05/24/2006] [Indexed: 11/29/2022]
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.
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