Neurotoxicity Research

, Volume 19, Issue 1, pp 63–72

Neuromelanin Activates Microglia and Induces Degeneration of Dopaminergic Neurons: Implications for Progression of Parkinson’s Disease

Authors

  • Wei Zhang
    • Department of NeurologyBeijing Tiantan Hospital
  • Kester Phillips
    • Department of Psychiatry, Neurology and PharmacologyColumbia University
  • Albert R. Wielgus
    • Neuropharmacology Section, Laboratory of Pharmacology and ChemistryNational Institute of Environmental Health Sciences/National Institutes of Health
  • Jie Liu
    • Inorganic Carcinogenesis Section, Laboratory of Comparative CarcinogenesisNational Cancer Institute, National Institute of Environmental Health Sciences/National Institutes of Health
  • Alberto Albertini
    • Institute of Biomedical Technologies-Italian National Research Council
  • Fabio A. Zucca
    • Institute of Biomedical Technologies-Italian National Research Council
  • Rudolph Faust
    • Department of Psychiatry, Neurology and PharmacologyColumbia University
  • Steven Y. Qian
    • Neuropharmacology Section, Laboratory of Pharmacology and ChemistryNational Institute of Environmental Health Sciences/National Institutes of Health
  • David S. Miller
    • Neuropharmacology Section, Laboratory of Pharmacology and ChemistryNational Institute of Environmental Health Sciences/National Institutes of Health
  • Colin F. Chignell
    • Neuropharmacology Section, Laboratory of Pharmacology and ChemistryNational Institute of Environmental Health Sciences/National Institutes of Health
  • Belinda Wilson
    • Neuropharmacology Section, Laboratory of Pharmacology and ChemistryNational Institute of Environmental Health Sciences/National Institutes of Health
  • Vernice Jackson-Lewis
    • Department of NeurologyColumbia University
  • Serge Przedborski
    • Department of Neurology, Pathology and Cell BiologyColumbia University
  • Danielle Joset
    • Department of Physiology and Cellular BiophysicsColumbia University
  • John Loike
    • Department of Physiology and Cellular BiophysicsColumbia University
  • Jau-Shyong Hong
    • Neuropharmacology Section, Laboratory of Pharmacology and ChemistryNational Institute of Environmental Health Sciences/National Institutes of Health
  • David Sulzer
    • Department of Psychiatry, Neurology and PharmacologyColumbia University
    • Institute of Biomedical Technologies-Italian National Research Council
Article

DOI: 10.1007/s12640-009-9140-z

Cite this article as:
Zhang, W., Phillips, K., Wielgus, A.R. et al. Neurotox Res (2011) 19: 63. doi:10.1007/s12640-009-9140-z

Abstract

In Parkinson’s disease (PD), there is a progressive loss of neuromelanin (NM)-containing dopamine neurons in substantia nigra (SN) which is associated with microgliosis and presence of extracellular NM. Herein, we have investigated the interplay between microglia and human NM on the degeneration of SN dopaminergic neurons. Although NM particles are phagocytized and degraded by microglia within minutes in vitro, extracellular NM particles induce microglial activation and ensuing production of superoxide, nitric oxide, hydrogen peroxide (H2O2), and pro-inflammatory factors. Furthermore, NM produces, in a microglia-depended manner, neurodegeneration in primary ventral midbrain cultures. Neurodegeneration was effectively attenuated with microglia derived from mice deficient in macrophage antigen complex-1, a microglial integrin receptor involved in the initiation of phagocytosis. Neuronal loss was also attenuated with microglia derived from mice deficient in phagocytic oxidase, a subunit of NADPH oxidase, that is responsible for superoxide and H2O2 production, or apocynin, an NADPH oxidase inhibitor. In vivo, NM injected into rat SN produces microgliosis and a loss of tyrosine hydroxylase neurons. Thus, these results show that extracellular NM can activate microglia, which in turn may induce dopaminergic neurodegeneration in PD. Our study may have far-reaching implications, both pathogenic and therapeutic.

Keywords

Substantia nigra Neuroinflammation Microglia Neurodegenerative diseases

Abbreviations

COX2

Cyclooxygenase 2

DA

Dopamine

DCF

Dichlorofluorescein

GABA

γ-Aminobutyric acid

GFAP

Glial filrillary acidic protein

H2O2

Hydrogen peroxide

IL

Interleukin

iNOS

Inducible NO synthase

iROS

Intracellular ROS

Mac-1

Macrophage antigen complex-1

Mac-1+/+

Wild-type Mac-1 mice

Mac-1−/−

Knockout Mac-1 mice

MIP-1α

Macrophage inflammatory protein-1α

NM

Neuromelanin

NO

Nitric oxide

PD

Parkinson’s disease

PHOX

Phagocytic oxidase

PHOX+/+

PHOX wild-type mice

PHOX−/−

PHOX-deficient mice

PMA

Phorbol ester myristate

ROS

Reactive oxygen species

SN

Substantia nigra

TH

Tyrosine hydroxylase

TH-ir

TH immunoreactive

TNF-α

Tumor necrosis factor-α

Supplementary material

12640_2009_9140_MOESM1_ESM.tif (270 kb)
Supplementary Fig. 1 NM, microglia, expression of pro-inflammatory cytokines and reactive nitrogen species. NM in microglia enriched cultures induced gene expression of mRNA of TNF-α (a; mean ± SEM; n = 3; * P < 0.001), IL-1β (b; mean ± SEM; n = 3; * P < 0.05; ** P < 0.01; *** P < 0.001) and iNOS (c; mean ± SEM; n = 3; * P < 0.01; ** P < 0.001) in a dose dependent manner (TIFF 270 kb)
12640_2009_9140_MOESM2_ESM.tif (86 kb)
Supplementary Fig. 2 NM activates microglia causing the release of NO. NM in microglia-enriched cultures induced a dose dependent release of NO measured as nitrite concentration (mean ± SEM; n = 3; * P < 0.01) (TIFF 86 kb)
12640_2009_9140_MOESM3_ESM.tif (273 kb)
Supplementary Fig. 3 NM, microglia, expression of inflammatory molecules and ROS. NM in microglia enriched cultures induced a dose dependent gene expression of MIP-1α (a; mean ± SEM; n = 3; * P < 0.05; ** P < 0.001), COX2 (b; mean ± SEM; n = 3; * P < 0.01; ** P < 0.001) and gp91 (c; mean ± SEM; n = 3; * P < 0.01; ** P < 0.001) (TIFF 274 kb)
12640_2009_9140_MOESM4_ESM.tif (208 kb)
Supplementary Fig. 4 Dose dependent release of iROS from microglia activated by NM and blockade by cytochalasin D. DCF fluorescence in response to NM, as an indicator of iROS production. (a) Indicates the dose dependence of iROS to increasing levels of NM (mean ± SEM; n = 4; * P < 0.05; ** P < 0.001). (b) iROS is inhibited by the phagocytic inhibitor, cytochalasin D (mean ± SEM; n = 3; * P < 0.05; ** P < 0.01) (TIFF 208 kb)

Copyright information

© Springer Science+Business Media, LLC 2009