Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts

Polyunsaturated fatty acid (PUFA) utilization was investigated in skin fibroblasts cultured from a female patient with an inherited abnormality in lipid metabolism. These deficient human skin fibroblasts (DF) converted 85–95% less [1-14C]linoleic acid (18:2n-6) to arachidonic acid (20:4n-6), 95% les...

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Main Authors: Deborah E. Williard, Joseph O. Nwankwo, Terry L. Kaduce, Shawn D. Harmon, Mira Irons, Hugo W. Moser, Gerald V. Raymond, Arthur A. Spector
Format: Article
Language:English
Published: Elsevier 2001-04-01
Series:Journal of Lipid Research
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0022227520303680
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author Deborah E. Williard
Joseph O. Nwankwo
Terry L. Kaduce
Shawn D. Harmon
Mira Irons
Hugo W. Moser
Gerald V. Raymond
Arthur A. Spector
author_facet Deborah E. Williard
Joseph O. Nwankwo
Terry L. Kaduce
Shawn D. Harmon
Mira Irons
Hugo W. Moser
Gerald V. Raymond
Arthur A. Spector
author_sort Deborah E. Williard
collection DOAJ
description Polyunsaturated fatty acid (PUFA) utilization was investigated in skin fibroblasts cultured from a female patient with an inherited abnormality in lipid metabolism. These deficient human skin fibroblasts (DF) converted 85–95% less [1-14C]linoleic acid (18:2n-6) to arachidonic acid (20:4n-6), 95% less [3-14C]tetracosatetraenoic acid (24:4n-6) to docosapentaenoic acid (22:5n-6), and 95% less [1-14C]-linolenic acid (18:3n-3) and [3-14C]tetracosapentaenoic acid (24:5n-3) to docosahexaenoic acid (22:6n-3) than did normal human skin fibroblasts (NF). The only product formed by the DF cultures from [1-14C]tetradecadienoic acid (14:2n-6) was 18:2n-6. However, they produced 50–90% as much 20:4n-6 as the NF cultures from [1-14C]hexadecatrienoic acid (16:3n-6), [1-14C]γ-linolenic acid (18:3n-6), and [1-14C]dihomo-γ-linolenic acid (20:3n-6), PUFA substrates that contain Δ6 double bonds. DF also contained 80% more 18:2n-6 and 25% less 20:4n-6. These results suggested that DF are deficient in Δ6 desaturation. This was confirmed by Northern blots demonstrating an 81–94% decrease in Δ6-desaturase mRNA content in the DF cultures, whereas the Δ5-desaturase mRNA content was reduced by only 14%. This is the first inherited abnormality in human PUFA metabolism shown to be associated with a Δ6-desaturase deficiency. Furthermore, the finding that the 18- and 24-carbon substrates are equally affected suggests that a single enzyme carries out both Δ6 desaturation reactions in human PUFA metabolism. —Williard, D. E., J. O. Nwankwo, T. L. Kaduce, S. D. Harmon, M. Irons, H. W. Moser, G. V. Raymond, and A. A. Spector. Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts. J. Lipid Res. 2001. 42: 501–508.
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spelling doaj.art-098e851cd49b4f2e816301dcf16873e22022-12-21T19:52:57ZengElsevierJournal of Lipid Research0022-22752001-04-01424501508Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblastsDeborah E. Williard0Joseph O. Nwankwo1Terry L. Kaduce2Shawn D. Harmon3Mira Irons4Hugo W. Moser5Gerald V. Raymond6Arthur A. Spector7Department of Biochemistry, University of Iowa, Iowa City, IA 52242Department of Biochemistry, University of Iowa, Iowa City, IA 52242Department of Biochemistry, University of Iowa, Iowa City, IA 52242Department of Biochemistry, University of Iowa, Iowa City, IA 52242Division of Genetics and Metabolism, Children's Hospital, Boston, MA 02111Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205Department of Biochemistry, University of Iowa, Iowa City, IA 52242; Department of Internal Medicine, University of Iowa, Iowa City, IA 52242; To whom correspondence should be addressed at the Department of Biochemistry, 4-403 BSB, University of Iowa, Iowa City, IA 52242.Polyunsaturated fatty acid (PUFA) utilization was investigated in skin fibroblasts cultured from a female patient with an inherited abnormality in lipid metabolism. These deficient human skin fibroblasts (DF) converted 85–95% less [1-14C]linoleic acid (18:2n-6) to arachidonic acid (20:4n-6), 95% less [3-14C]tetracosatetraenoic acid (24:4n-6) to docosapentaenoic acid (22:5n-6), and 95% less [1-14C]-linolenic acid (18:3n-3) and [3-14C]tetracosapentaenoic acid (24:5n-3) to docosahexaenoic acid (22:6n-3) than did normal human skin fibroblasts (NF). The only product formed by the DF cultures from [1-14C]tetradecadienoic acid (14:2n-6) was 18:2n-6. However, they produced 50–90% as much 20:4n-6 as the NF cultures from [1-14C]hexadecatrienoic acid (16:3n-6), [1-14C]γ-linolenic acid (18:3n-6), and [1-14C]dihomo-γ-linolenic acid (20:3n-6), PUFA substrates that contain Δ6 double bonds. DF also contained 80% more 18:2n-6 and 25% less 20:4n-6. These results suggested that DF are deficient in Δ6 desaturation. This was confirmed by Northern blots demonstrating an 81–94% decrease in Δ6-desaturase mRNA content in the DF cultures, whereas the Δ5-desaturase mRNA content was reduced by only 14%. This is the first inherited abnormality in human PUFA metabolism shown to be associated with a Δ6-desaturase deficiency. Furthermore, the finding that the 18- and 24-carbon substrates are equally affected suggests that a single enzyme carries out both Δ6 desaturation reactions in human PUFA metabolism. —Williard, D. E., J. O. Nwankwo, T. L. Kaduce, S. D. Harmon, M. Irons, H. W. Moser, G. V. Raymond, and A. A. Spector. Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts. J. Lipid Res. 2001. 42: 501–508.http://www.sciencedirect.com/science/article/pii/S0022227520303680polyunsaturated fatty acidsfatty acid desaturationΔ5-desaturaselinoleic acidα-linolenic acidarachidonic acid
spellingShingle Deborah E. Williard
Joseph O. Nwankwo
Terry L. Kaduce
Shawn D. Harmon
Mira Irons
Hugo W. Moser
Gerald V. Raymond
Arthur A. Spector
Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts
Journal of Lipid Research
polyunsaturated fatty acids
fatty acid desaturation
Δ5-desaturase
linoleic acid
α-linolenic acid
arachidonic acid
title Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts
title_full Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts
title_fullStr Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts
title_full_unstemmed Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts
title_short Identification of a fatty acid Δ6-desaturase deficiency in human skin fibroblasts
title_sort identification of a fatty acid δ6 desaturase deficiency in human skin fibroblasts
topic polyunsaturated fatty acids
fatty acid desaturation
Δ5-desaturase
linoleic acid
α-linolenic acid
arachidonic acid
url http://www.sciencedirect.com/science/article/pii/S0022227520303680
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