The dopamine metabolite aminochrome inhibits mitochondrial complex I and modifies the expression of iron transporters DMT1 and FPN1.

Abstract

Hallmarks of idiopathic and some forms of familial Parkinson’s disease are mitochondrial dysfunction, iron accumulation and oxidative stress in dopaminergic neurons of the substantia nigra. There seems to be a causal link between these three conditions, since mitochondrial dysfunction can give rise to increased electron leak and reactive oxygen species production. In turn, recent evidence indicates that diminished activity of mitochondrial complex I results in decreased Fe–S cluster synthesis and anomalous activation of Iron Regulatory Protein 1. Thus, mitochondrial dysfunction could be a founding event in the process that leads to neuronal death. Here, we present evidence showing that at low micromolar concentrations, the dopamine metabolite aminochrome inhibits complex I and ATP production in SH-SY5Y neuroblastoma cells differentiated into a dopaminergic phenotype. This effect is apparently direct, since it is replicated in isolated mitochondria. Additionally, overnight treatment with aminochrome increased the expression of the iron import transporter divalent metal transporter 1 and decreased the expression of the iron export transporter ferroportin 1. In accordance with these findings, cells treated with aminochrome presented increased iron uptake. These results suggest that aminochrome is an endogenous toxin that inhibits by oxidative modifications mitochondrial complex I and modifies the levels of iron transporters in a way that leads to iron accumulation.

• Authors: Pabla Aguirre, Pamela Urrutia, Victoria Tapia, Monica Villa, Irmgad Paris, Juan Segura-Aguilar, Marco T Núñez
• Journal: Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine (Biometals) Vol. 25 Issue 4 Pg. 795-803 (Aug 2012) ISSN: 1572-8773 [Electronic] Netherlands
• PMID: 22302610 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cation Transport Proteins
• Indolequinones
• metal transporting protein 1
• solute carrier family 11- (proton-coupled divalent metal ion transporters), member 2
• aminochrome 1
• Electron Transport Complex I
• Dopamine

Topics

• Cation Transport Proteins (genetics, metabolism)
• Cell Line, Tumor
• Cell Survival (drug effects)
• Dopamine (metabolism)
• Electron Transport Complex I (drug effects, metabolism)
• Humans
• Indolequinones (metabolism, pharmacology)
• Mitochondria (drug effects, metabolism)
• Reverse Transcriptase Polymerase Chain Reaction