S-sulfocysteine/NMDA receptor-dependent signaling underlies neurodegeneration in molybdenum cofactor deficiency

Autor: Kumar, A., Dejanovic, B., Hetsch, F., Semtner, M., Fusca, D., Arjune, S., Santamaria-Araujo, J.A., Winkelmann, A., Ayton, S., Bush, A.I., Kloppenburg, P., Meier, J.C., Schwarz, G., Belaidi, A.A.
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Popis: Molybdenum cofactor deficiency (MoCD) is an autosomal recessive inborn error of metabolism characterized by neurodegeneration and death in early childhood. The rapid and progressive neurodegeneration in MoCD presents a major clinical challenge and may relate to the poor understanding of the molecular mechanisms involved. Recently, we reported that treating patients with cyclic pyranopterin monophosphate (cPMP) is a successful therapy for a subset of infants with MoCD and prevents irreversible brain damage. Here, we studied S-sulfocysteine (SSC), a structural analog of glutamate that accumulates in the plasma and urine of patients with MoCD, and demonstrated that it acts as an N-methyl D-aspartate receptor (NMDA-R) agonist, leading to calcium influx and downstream cell signaling events and neurotoxicity. SSC treatment activated the protease calpain, and calpain-dependent degradation of the inhibitory synaptic protein gephyrin subsequently exacerbated SSC-mediated excitotoxicity and promoted loss of GABAergic synapses. Pharmacological blockade of NMDA-R, calcium influx, or calpain activity abolished SSC and glutamate neurotoxicity in primary murine neurons. Finally, the NMDA-R antagonist memantine was protective against the manifestation of symptoms in a tungstate-induced MoCD mouse model. These findings demonstrate that SSC drives excitotoxic neurodegeneration in MoCD and introduce NMDA-R antagonists as potential therapeutics for this fatal disease.
Databáze: OpenAIRE