Ectopic deposition of melanin pigments as detoxifying mechanism: A paradigm for basal nuclei pigmentation

Federico De Marco, Cesira Foppoli, Raffaella Coccia, Carla Blarzino, Marzia Perluigi, Chiara Cini, Maria Luisa Marcante

Research output: Contribution to journalArticlepeer-review

Abstract

Melanins are UV shielding pigments found in skin and other light exposed tissues. However, a kind of melanin, named neuromelanin (NM), is found in those deep brain loci that degenerate in Parkinson's disease (PD), where no such a function may be imagined. The NM synthetic pathway, different from the one of eumelanin based on tyrosinase, is still obscure as well as its physiological function. Here we show that under conditions of excess of toxic quinone concentration, nonmelanocytic cell strains (i.e., primary keratinocytes) may accumulate a dark cytoplasmatic pigment that proved to be a melanin. The ability of pigment deposition, possibly driven by peroxidases, is restricted to diploid cells and increases cell survival acting as a sink for potentially hazardous quinones. We suggest that in the basal nuclei, exposed to high level of catecholaminergic neurotransmitters, NM deposition is a relevant antioxidant mechanism by trapping quinones and semiquinones, thus protecting neurons from accumulating damage over many years. In this perspective, just as a hypothesis, we may imagine that PD neuron degeneration is the consequence of a reduced/abrogated ability to produce neuromelanin.

Original languageEnglish
Pages (from-to)631-637
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume314
Issue number2
DOIs
Publication statusPublished - Feb 6 2004

Keywords

  • Human keratinocytes
  • Melanin
  • Neuromelanin
  • Parkinson's disease
  • Peroxidase
  • Tetrahydropapaveroline

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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