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1-Deoxysphingolipid-induced neurotoxicity involves N-methyl-d-aspartate receptor signaling

journal contribution
posted on 2023-05-19, 19:59 authored by Guntert, T, Hanggi, P, Othman, A, Suriyanarayanan, S, Sabrina SondaSabrina Sonda, Zuelling, RA, Hornemann, T, Ogunshola, OO
1-Deoxysphingolipids (1-deoxySL) are atypical and neurotoxic sphingolipids formed by alternate substrate usage of the enzyme serine-palmitoyltransferase. Pathologically increased 1-deoxySL formation causes hereditary sensory and autosomal neuropathy type 1 (HSAN1) - a progressive peripheral axonopathy. However, the underlying molecular mechanisms by which 1-deoxySL acts are unknown. Herein we studied the effect of 1-deoxysphinganine (1-deoxySA) and its canonical counterpart sphinganine (SA) in aged cultured neurons comparing their outcome on cell survival and cytoskeleton integrity. 1-deoxySA caused rapid neuronal cytoskeleton disruption and modulated important cytoskeletal regulatory and associated components including Rac1, Ezrin and insulin receptor substrate 53. We show that 1-deoxySA is internalized and metabolized downstream to 1-deoxydihydroceramide since inhibition of ceramide synthase protected neurons from 1-deoxySA-mediated cell death. In addition, 1-deoxySA reduced protein levels of N-methyl-d-aspartate receptor (NMDAR) subunit GluN2B, the postsynaptic density protein 95 and induced cleavage of p35 to p25. Notably, blocking NMDAR activation by MK-801 or memantine significantly prevented 1-deoxySA neurotoxicity. Functional studies of differentiating primary neurons via the patch-clamp technique demonstrated that 1-deoxySA irreversibly depolarizes the neuronal membrane potential in an age-dependent manner. Notably, only neuronal cells that displayed functional NMDAR- and NMDA-induced whole-cell currents responded to 1-deoxySA treatment. Furthermore, pre-exposure to the non-competitive antagonist MK-801 blocked the current response of NMDA and glycine, as well as 1-deoxySA. We conclude that 1-deoxySA-induced neurotoxicity compromises cytoskeletal stability and targets NMDAR signaling in an age-dependent manner. Thus stabilization of cytoskeletal structures and/or inhibition of glutamate receptors could be a potential therapeutic approach to prevent 1-deoxySA-induced neurodegeneration.


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School of Health Sciences


Pergamon-Elsevier Science Ltd

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Copyright 2016 Elsevier Ltd.

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