TY - JOUR
T1 - Calpain, not caspase, is the causative protease for hypoxic damage in cultured monkey retinal cells
AU - Nakajima, Emi
AU - Hammond, Katherine B.
AU - Rosales, Jennifer L.
AU - Shearer, Thomas R.
AU - Azuma, Mitsuyoshi
PY - 2011/9
Y1 - 2011/9
N2 - PURPOSE. Cell death occurring in human retina during AMD, high IOP, and diabetic retinopathy could be caused by activation of calpain or caspase proteolytic enzymes. The purpose of the present study was to determine whether calpains and/or caspase-3 were involved in cell death during retinal hypoxia in a monkey model. METHODS. Dissociated monkey retinal cells were cultured for two weeks and subjected to 24-hour hypoxia/24-hour reoxygenation. TUNEL staining and immunostaining for Müller and photoreceptor markers were used to detect which retinal cell types were damaged. RESULTS. Culturing dissociated monkey retina cells for two weeks resulted in proliferation of Müller cells and maintenance of some rod and cone photoreceptor cells, as identified by vimentin, recoverin, and rhodopsin immunocytochemical staining. Hypoxia/reoxygenation increased the number of cells staining positive for TUNEL. Immunoblotting showed that the calpain-specific 145 kDa α-spectrin breakdown product (SBDP) increased in hypoxic cells, but no caspase-specific 120 kDa α -spectrin breakdown product was detected. TUNEL staining and proteolysis were significantly reduced in the retinal cells treated with 10 and 100 μM calpain inhibitor SNJ-1945. Caspase inhibitor, z-VAD, did not inhibit cell damage from hypoxia/reoxygenation. Intact pro-caspase-3 was in fact cleaved by activated calpain during hypoxia/reoxygenation to pre 29 kDa caspase-3 and 24 kDa inactive fragments. No 17 and 12 kDa fragments, which form the active caspase-3 heterodimer, were detected. Calpain-induced cleavage of caspase was inhibited by SNJ-1945. CONCLUSIONS. Calpain, not caspase-3, was involved in hypoxic damage in cultured monkey retinal cells. copy; 2011 The Association for Research in Vision and Ophthalmology, Inc.
AB - PURPOSE. Cell death occurring in human retina during AMD, high IOP, and diabetic retinopathy could be caused by activation of calpain or caspase proteolytic enzymes. The purpose of the present study was to determine whether calpains and/or caspase-3 were involved in cell death during retinal hypoxia in a monkey model. METHODS. Dissociated monkey retinal cells were cultured for two weeks and subjected to 24-hour hypoxia/24-hour reoxygenation. TUNEL staining and immunostaining for Müller and photoreceptor markers were used to detect which retinal cell types were damaged. RESULTS. Culturing dissociated monkey retina cells for two weeks resulted in proliferation of Müller cells and maintenance of some rod and cone photoreceptor cells, as identified by vimentin, recoverin, and rhodopsin immunocytochemical staining. Hypoxia/reoxygenation increased the number of cells staining positive for TUNEL. Immunoblotting showed that the calpain-specific 145 kDa α-spectrin breakdown product (SBDP) increased in hypoxic cells, but no caspase-specific 120 kDa α -spectrin breakdown product was detected. TUNEL staining and proteolysis were significantly reduced in the retinal cells treated with 10 and 100 μM calpain inhibitor SNJ-1945. Caspase inhibitor, z-VAD, did not inhibit cell damage from hypoxia/reoxygenation. Intact pro-caspase-3 was in fact cleaved by activated calpain during hypoxia/reoxygenation to pre 29 kDa caspase-3 and 24 kDa inactive fragments. No 17 and 12 kDa fragments, which form the active caspase-3 heterodimer, were detected. Calpain-induced cleavage of caspase was inhibited by SNJ-1945. CONCLUSIONS. Calpain, not caspase-3, was involved in hypoxic damage in cultured monkey retinal cells. copy; 2011 The Association for Research in Vision and Ophthalmology, Inc.
UR - http://www.scopus.com/inward/record.url?scp=80052474977&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80052474977&partnerID=8YFLogxK
U2 - 10.1167/iovs.11-7497
DO - 10.1167/iovs.11-7497
M3 - Article
C2 - 21757584
AN - SCOPUS:80052474977
SN - 0146-0404
VL - 52
SP - 7059
EP - 7067
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 10
ER -