Loss of SPTSSA Impairs Mitochondrial Function and Neuronal Differentiation in SH-SY5Y Neuroblastoma Cells

ABSTRACT: Sphingolipids are bioactive membrane and signaling lipids that not only shape cellular architecture but also orchestrate a network of interconnected metabolic pathways. Their core building blocks, sphingoid bases, are synthesized by the serine palmitoyltransferase (SPT) complex. At its core, the SPT complex contains two large subunits (SPTLC1 with either SPTLC2 or SPTLC3) and one small subunit (SPTSSA or SPTSSB). Thereby it establishes the ganglioside composition of the aging brain. To investigate the functional impact of altered sphingolipid composition on cell physiology, we generated SPTSSA knockout (KO) SH-SY5Y neuroblastoma cell lines still expressing SPTSSB and characterized them through multiomics approaches. SPTSSA KO led to increase in the ratio of C20/C18-sphingosine containing ceramides. Multiomics analysis revealed significant mitochondrial dysfunction, with upregulation of electron transport chain complexes I, III and V but downregulation of complex IV. These changes led to reduced ATP levels, alternation in NAD+/NADH and GSH/GSSG ratios. Elevated L-lactic acid and glyceraldehyde 3-phosphate levels indicated a metabolic shift toward glycolysis. Most critically, upon B27/all-trans retinoic acid (ATRA) treatment, SPTSSA KO cells had impaired neuronal differentiation capacity and gradually died over time. Overall, alterations in SPT complex composition through SPTSSA deletion altered cellular proteome and metabolome. These findings demonstrate that fine-tuning and proper ratio of C18- and C20-sphingosine containing sphingolipids are essential for mitochondrial homeostasis and successful neuronal differentiation in SH-SY5Y neuroblastoma cells.

INSTRUMENT(S): Liquid Chromatography MS - alternating - hilic, Liquid Chromatography MS - negative - reverse-phase, Liquid Chromatography MS - positive - reverse-phase

PROVIDER: MTBLS15875 | MetaboLights | 2026-10-09

REPOSITORIES: MetaboLights