iScience (Dec 2020)

Human Dopaminergic Neurons Lacking PINK1 Exhibit Disrupted Dopamine Metabolism Related to Vitamin B6 Co-Factors

  • Christine Bus,
  • Laimdota Zizmare,
  • Marita Feldkaemper,
  • Sven Geisler,
  • Maria Zarani,
  • Anna Schaedler,
  • Franziska Klose,
  • Jakob Admard,
  • Craig J. Mageean,
  • Giuseppe Arena,
  • Petra Fallier-Becker,
  • Aslihan Ugun-Klusek,
  • Klaudia K. Maruszczak,
  • Konstantina Kapolou,
  • Benjamin Schmid,
  • Doron Rapaport,
  • Marius Ueffing,
  • Nicolas Casadei,
  • Rejko Krüger,
  • Thomas Gasser,
  • Daniela M. Vogt Weisenhorn,
  • Philipp J. Kahle,
  • Christoph Trautwein,
  • Christian J. Gloeckner,
  • Julia C. Fitzgerald

Journal volume & issue
Vol. 23, no. 12
p. 101797

Abstract

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Summary: PINK1 loss-of-function mutations cause early onset Parkinson disease. PINK1-Parkin mediated mitophagy has been well studied, but the relevance of the endogenous process in the brain is debated.Here, the absence of PINK1 in human dopaminergic neurons inhibits ionophore-induced mitophagy and reduces mitochondrial membrane potential. Compensatory, mitochondrial renewal maintains mitochondrial morphology and protects the respiratory chain. This is paralleled by metabolic changes, including inhibition of the TCA cycle enzyme mAconitase, accumulation of NAD+, and metabolite depletion. Loss of PINK1 disrupts dopamine metabolism by critically affecting its synthesis and uptake. The mechanism involves steering of key amino acids toward energy production rather than neurotransmitter metabolism and involves cofactors related to the vitamin B6 salvage pathway identified using unbiased multi-omics approaches.We propose that reduction of mitochondrial membrane potential that cannot be controlled by PINK1 signaling initiates metabolic compensation that has neurometabolic consequences relevant to Parkinson disease.

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