Loss of delta6-desaturase activity leads to impaired docosahexaenoic acid synthesis in Y-79 retinoblastoma cells.
We have studied the synthesis of docosahexaenoic acid (22:6 n-3) from linolenic acid (18:3 n-3) and eicosapentaenoic acid (20:5 n-3) in Y-79 human retinoblastoma cells and in a derived cell line, Y-79a, which has lost delta6-desaturase activity. Whereas Y-79 cells efficiently converted both radiolabeled 18:3 n-3 and 20:5 n-3 to 22:6 n-3, no synthesis of this fatty acid was observed in Y-79a cells from either 18:3 n-3 or 20:5 n-3. Y-79a cells elongated 18:3 n-3 to 20:3 n-3, which was further converted to 5,11,14,17-20:4 through a delta5-desaturation, elongated 20:5 n-3 to 22:5 n-3 and 24:5 n-3, and retained the ability for retroconversion. These results underscore the key role of delta6-desaturase in the synthesis of 22:6 n-3 and stress the importance of an adequate supply of this fatty acid in situations of reduced delta6-desaturase activity, such as in perinatal period, to prevent a 22:6 n-3 deficiency status.
Marzo
I
I
Departamento de Bioquimica y Biologia Molecular Y Celular, Facultad de Ciencias, Universidad de Zaragoza, Spain.
Piñeiro
A
A
Naval
J
J
D004281:Docosahexaenoic Acids / Q000378:metabolism*; D015118:Eicosapentaenoic Acid / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis; D006801:Humans; D008042:Linolenic Acids / Q000378:metabolism; D050602:Linoleoyl-CoA Desaturase; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D019572:Retinal Neoplasms / Q000378:metabolism*; D012175:Retinoblastoma / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D005227:Fatty Acids; D008042:Linolenic Acids; D008055:Lipids; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase