Dual effects of antioxidants in neurodegeneration: Direct neuroprotection against oxidative stress and indirect protection via suppression of glia-mediated inflammation

Jia Yi Wang, Li Li Wen, Ya Ni Huang, Yen Tsun Chen, Min Chi Ku

Research output: Contribution to journalArticle

188 Citations (Scopus)

Abstract

Oxidative stress, in which production of highly reactive oxygen species (ROS) and reactive nitrogen species (RNS) overwhelms antioxidant defenses, is a feature of many neurological diseases and neurodegeneration. ROS and RNS generated extracellularly and intracellularly by various processes initiate and promote neurodegeneration in CNS. ROS and RNS can directly oxidize and damage macromolecules such as DNA, proteins, and lipids, culminating in neurodegeneration in the CNS. Neurons are most susceptible to direct oxidative injury by ROS and RNS. ROS and RNS can also indirectly contribute to tissue damage by activating a number of cellular pathways resulting in the expression of stress-sensitive genes and proteins to cause oxidative injury. Moreover, oxidative stress also activates mechanisms that result in a glia-mediated inflammation that also causes secondary neuronal damage. Associated with neuronal injuries caused by many CNS insults is an activation of glial cells (particularly astrocytes and microglia) at the sites of injury. Activated glial cells are thus histopathological hallmarks of neurodegenerative diseases. Even though direct contact of activated glia with neurons per se may not necessarily be toxic, the immune mediators (e.g. nitric oxide and reactive oxygen species, pro-inflammatory cytokines and chemokines) released by activated glial cells are currently considered to be candidate neurotoxins. Therefore, study of the protective role of antioxidant compounds on inhibition of the inflammatory response and correcting the fundamental oxidant/antioxidant imbalance in patients suffering from neurodegenerative diseases are important vistas for further research. The purpose of this review is to summarize the current evidence in support of this critical role played by oxidative stress of neuronal and glial origin in neurodegenerative diseases. The mechanistic basis of the neuroprotective activity of antioxidants does not only rely on the general free radical trapping or antioxidant activity per se in neurons, but also the suppression of genes induced by pro-inflammatory cytokines and other mediators released by glial cells. We propose that combinations of agents which act at sequential steps in the neurodegenerative process can produce additive neuroprotective effects. A cocktail of multiple antioxidants with anti-inflammatory agents may be more beneficial in the prevention of neurodegenerative disease. A clearer appreciation of the potential therapeutic utility of antioxidants would emerge only when the complexity of their effects on mechanisms that interact to determine the extent of oxidative damage in vivo are more fully defined and understood.

Original languageEnglish
Pages (from-to)3521-3533
Number of pages13
JournalCurrent Pharmaceutical Design
Volume12
Issue number27
DOIs
Publication statusPublished - Sep 2006
Externally publishedYes

Fingerprint

Neuroglia
Reactive Nitrogen Species
Oxidative Stress
Antioxidants
Reactive Oxygen Species
Inflammation
Neurodegenerative Diseases
Wounds and Injuries
Neurons
Cytokines
Poisons
Neurotoxins
Microglia
Neuroprotective Agents
Neuroprotection
Chemokines
Oxidants
Astrocytes
Free Radicals
Nitric Oxide

Keywords

  • Alzheimer's disease (AD)
  • Amyotrophic lateral sclerosis (ALS)
  • Glia
  • Inflammatory mediators
  • Microglia
  • Neuron
  • Oxidative stress
  • Parkinson's disease (PD)
  • Re-dox genes
  • RNS
  • ROS

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology, Toxicology and Pharmaceutics(all)

Cite this

Dual effects of antioxidants in neurodegeneration : Direct neuroprotection against oxidative stress and indirect protection via suppression of glia-mediated inflammation. / Wang, Jia Yi; Wen, Li Li; Huang, Ya Ni; Chen, Yen Tsun; Ku, Min Chi.

In: Current Pharmaceutical Design, Vol. 12, No. 27, 09.2006, p. 3521-3533.

Research output: Contribution to journalArticle

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