title: Acyl-CoA synthetase 2 overexpression enhances fatty acid internalization and neurite outgrowth.
abstract: During neurodevelopment neurons increase phospholipid synthesis to generate additional plasma membrane that makes up the growing neurites. Compared with most cell types, neurons contain a high percentage of the polyunsaturated fatty acids (PUFAs) arachidonic acid (AA) and docosahexaenoic acid (DHA). By utilizing PC12 cell lines as a model neuronal cell line, we examined the internalization rate of AA, DHA, and non-essential oleic acid (OA), as well as their effects on neurite outgrowth. When wild type cells were differentiated, the rate of AA and DHA internalization increased 50% more than the rate of OA internalization. When media were supplemented with AA or DHA, the average neurite length was increased by approximately 40%, but supplementation with the same amount of OA had no effect. We also increased the levels of acyl-CoA synthetase-1 (ACS1) and ACS2 proteins to determine whether they contribute to PUFA internalization or neurite outgrowth. Overexpression of ACS1 increased the rate of OA internalization by 55%, and AA and DHA uptake was increased by 25%, but there was no significant change in neurite outgrowth. In ACS2-overexpressing cells, in contrast, the rate of OA internalization increased by 90%, AA by 115%, and DHA by 70%. The average aggregate neurite length in ACS2-overexpressing cells was increased by approximately 40% when the media were supplemented with PUFAs, but there was no change with OA supplementation. Taken together, these results support the hypotheses that ACSs are rate-limiting for fatty acid internalization and that ACS2 enhances neurite outgrowth by promoting PUFA internalization.
authors.affiliation: Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Marszalek
authors.forename: Claire
authors.initials: C
authors.lastname: Kitidis
authors.forename: Ariya
authors.initials: A
authors.lastname: Dararutana
authors.forename: Harvey F
authors.initials: HF
authors.lastname: Lodish
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D002469:Cell Separation; D003066:Coenzyme A Ligases / Q000096:biosynthesis* / Q000378:metabolism / Q000502:physiology*; D004281:Docosahexaenoic Acids / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D019301:Oleic Acid / Q000378:metabolism; D016716:PC12 Cells; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
chemical_list: D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D008164:Luminescent Proteins; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; D019301:Oleic Acid; D003066:Coenzyme A Ligases; C403665:ACSL6 protein, human; C561832:Acsl1 protein, rat