Retinoid processing in cone and Müller cell lines.
To determine whether cones and Müller cells in the rod dominated retina cooperate to regenerate the 11-cis retinal chromophore via the retinoid cycle, two cell lines from the rod dominated retinas of Murine were used for this study: 661W, a mouse cell line derived from cones, and rMC-1, a rat Müller cell line. Retinoid cycle enzymes were analyzed by RT-PCR, and their catalytic activity was detected by incubation with retinoids and analyzed by HPLC. We found that 661W cells are capable of reducing all-trans retinal to all-trans retinol due to the presence of multiple dehydrogenases and to generate minor amounts of retinyl-ester. The rMC-1 cells take up all-trans retinol and oxidize it to all-trans retinal or esterify it to retinyl-ester, but are incapable of isomerizing all-trans retinoids to 11-cis retinoids. This could be a reflection of lack of necessary activities in Müller cells in vivo, which suggests that Müller cells do not contribute to retinoid cycling by regenerating 11-cis retinoids. Alternatively, this could be due to the potential that rMC-1, as a transformed cell line, has stopped expressing the proteins needed for the regeneration of 11-cis retinoids.
Kanan
Yogita
Y
Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Kasus-Jacobi
Anne
A
Moiseyev
Gennadiy
G
Sawyer
Kjell
K
Ma
Jian-Xing
JX
Al-Ubaidi
Muayyad R
MR
D000818:Animals; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004952:Esters / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000502:physiology; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000378:metabolism; D010775:Photic Stimulation; D012160:Retina / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism; D012172:Retinaldehyde / Q000378:metabolism; D012176:Retinoids / Q000378:metabolism*; D051142:Retinol O-Fatty-Acyltransferase / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014801:Vitamin A / Q000378:metabolism
D004952:Esters; D012176:Retinoids; D014801:Vitamin A; D010088:Oxidoreductases; D007862:Phosphatidylcholine-Sterol O-Acyltransferase; D051142:Retinol O-Fatty-Acyltransferase; D012172:Retinaldehyde