Lipid metabolism alterations in the neuronal response to A53T α-synuclein and Fe-induced injury

Abstract

Pathological α-synuclein (α-syn) overexpression and iron (Fe)-induced oxidative stress (OS) are involved in the death of dopaminergic neurons in Parkinson's disease (PD). We have previously characterized the role of triacylglycerol (TAG) formation in the neuronal response to Fe-induced OS. In this work we characterize the role of the α-syn variant A53T during Fe-induced injury and investigate whether lipid metabolism has implications for neuronal fate. To this end, we used the N27 dopaminergic neuronal cell line either untransfected (UT) or stably transfected with pcDNA3 vector (as a transfection control) or pcDNA-A53T-α-syn (A53T α-syn). The overexpression of A53T α-syn triggered an increase in TAG content mainly due to the activation of Acyl-CoA synthetase. Since fatty acid (FA) β-oxidation and phospholipid content did not change in A53T α-syn cells, the unique consequence of the increase in FA-CoA derivatives was their acylation in TAG moieties. Control cells exposed to Fe-induced injury displayed increased OS markers and TAG content. Intriguingly, Fe exposure in A53T α-syn cells promoted a decrease in OS markers accompanied by α-syn aggregation and elevated TAG content. We report here new evidence of a differential role played by A53T α-syn in neuronal lipid metabolism as related to the neuronal response to OS.

Keywords: 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide; A53T α-syn cell; A53T α-synuclein; ACS; Acyl-CoA synthetase; BSA; Chol; DAG; DCDCDHF; DTT; Dopaminergic neurons; EDTA; FA; FAME; FAS; FBS; FFA; GC; HRP; Iron; LDH; Lipid metabolism; MAG; MTT; N,N′-1,2-ethandiylbis[N-(carboxymethyl)glycine] disodium salt; N27 neurons expressing the empty vector pcDNA3; N27 neurons expressing the vector pcDNA3-A53T α-synuclein; OA; OS; Oleic acid; Oxidative stress; PBS; PD; PL; PMSF; Parkinson's disease; ROS; SDS; SDS–PAGE; TAG; TBA; TBARS; TBS-T; Triacylglycerol; Tween-Tris Buffer Saline; UT; bovine serum albumin; cholesterol; diacylglycerols; dichlorodihydrofluorescein diacetate; dithiothreitol; fatty acid; fatty acid methyl esters; fatty acid synthase; fetal bovine serum; free fatty acid; gas-liquid chromatography; horseradish peroxidase; lactate dehydrogenase; monoacylglycerol; oxidative stress; pcDNA cells; phenylmethylsulfonyl fluoride; phosphate buffer saline; phospholipids; reactive oxygen species; sodium dodecyl sulphate; sodium dodecyl sulphate-polyacrylmide gel electrophoresis; thiobarbituric acid; thiobarbituric acid reactive substances; triacylglycerols; untransfected neurons; α-syn; α-synuclein.