PURPOSE: RPE65, a major retinal pigment epithelium protein, is essential in generating 11-cis retinal, the chromophore for all opsins. Without chromophore, cone opsins are mislocalized and cones degenerate rapidly (e.g., Rpe65(-/-) mouse). Function, survival, and correct targeting of opsins is increased in Rpe65(-/-) cones on supplying 11-cis retinal. Here, we determine the consequences of 11-cis retinal withdrawal and supplementation on cone development in the all-cone Nrl(-/-) retina. METHODS: Rpe65(-/-) Nrl(-/-), Nrl(-/-), and wild-type mice were examined. Cone structure was analyzed by using TUNEL assay, electron microscopy, and cone-specific antibodies. Cone function was assessed with light-adapted single-flash ERGs. RESULTS: Rpe65(-/-)Nrl(-/-) mice had an increased number of TUNEL-positive photoreceptors during programmed cell death compared with Nrl(-/-) mice, in addition to accelerated age-related degeneration. Cone function in Rpe65(-/-)Nrl(-/-) mice was minimal, and opsins were mislocalized. Treatment with 11-cis retinal restored cone function, promoted outer segment formation, and enabled opsin trafficking to outer segments. Eliminating Rpe65 prevented rosette formation in Nrl(-/-) retinas; supplementation of Rpe65(-/-)Nrl(-/-) mice with 11-cis retinal resulted in their reoccurrence. CONCLUSIONS: Taken together, function and opsin trafficking in Nrl(-/-) and wild-type cones are comparable, confirming and extending our findings that cone maturation and outer segment development are dependent on the presence of chromophore. The data on age-related cone death in Rpe65(-/-)Nrl(-/-) mice and the reintroduction of rosettes after 11-cis retinal injections confirm that outer segments, which for steric reasons appear to introduce rosettes in an all-cone retina, are essential for cell survival. These results are important for understanding and treating chromophore-related cone dystrophies.
PURPOSE:RPE65, a major retinal pigment epithelium protein, is essential in generating 11-cis retinal, the chromophore for all opsins. Without chromophore, cone opsins are mislocalized and cones degenerate rapidly (e.g., Rpe65(-/-) mouse). Function, survival, and correct targeting of opsins is increased in Rpe65(-/-) cones on supplying 11-cis retinal. Here, we determine the consequences of 11-cis retinal withdrawal and supplementation on cone development in the all-cone Nrl(-/-) retina. METHODS:Rpe65(-/-) Nrl(-/-), Nrl(-/-), and wild-type mice were examined. Cone structure was analyzed by using TUNEL assay, electron microscopy, and cone-specific antibodies. Cone function was assessed with light-adapted single-flash ERGs. RESULTS:Rpe65(-/-)Nrl(-/-) mice had an increased number of TUNEL-positive photoreceptors during programmed cell death compared with Nrl(-/-) mice, in addition to accelerated age-related degeneration. Cone function in Rpe65(-/-)Nrl(-/-) mice was minimal, and opsins were mislocalized. Treatment with 11-cis retinal restored cone function, promoted outer segment formation, and enabled opsin trafficking to outer segments. Eliminating Rpe65 prevented rosette formation in Nrl(-/-) retinas; supplementation of Rpe65(-/-)Nrl(-/-) mice with 11-cis retinal resulted in their reoccurrence. CONCLUSIONS: Taken together, function and opsin trafficking in Nrl(-/-) and wild-type cones are comparable, confirming and extending our findings that cone maturation and outer segment development are dependent on the presence of chromophore. The data on age-related cone death in Rpe65(-/-)Nrl(-/-) mice and the reintroduction of rosettes after 11-cis retinal injections confirm that outer segments, which for steric reasons appear to introduce rosettes in an all-cone retina, are essential for cell survival. These results are important for understanding and treating chromophore-related cone dystrophies.
Authors: Hongwei Ma; Fan Yang; Michael R Butler; Joshua Belcher; T Michael Redmond; Andrew T Placzek; Thomas S Scanlan; Xi-Qin Ding Journal: FASEB J Date: 2017-04-20 Impact factor: 5.191
Authors: Xi-Qin Ding; Arjun Thapa; Hongwei Ma; Jianhua Xu; Michael H Elliott; Karla K Rodgers; Marci L Smith; Jin-Shan Wang; Steven J Pittler; Vladimir J Kefalov Journal: J Biol Chem Date: 2016-02-18 Impact factor: 5.157
Authors: Jerome E Roger; Keerthi Ranganath; Lian Zhao; Radu I Cojocaru; Matthew Brooks; Norimoto Gotoh; Shobi Veleri; Avinash Hiriyanna; Rivka A Rachel; Maria Mercedes Campos; Robert N Fariss; Wai T Wong; Anand Swaroop Journal: J Neurosci Date: 2012-01-11 Impact factor: 6.167
Authors: Fan Yang; Hongwei Ma; Joshua Belcher; Michael R Butler; T Michael Redmond; Sanford L Boye; William W Hauswirth; Xi-Qin Ding Journal: FASEB J Date: 2016-09-13 Impact factor: 5.191