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2021-03-20
Depletion of Reduced Glutathione Enhances Motor Neuron Degeneration in vitro
and in vivo; PY2007; USA (美國);_WJD_2021-0320_V001R01_IR94_IR95_RvD20210320_
Source (資訊來源):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1944995/
Info cited on 2021-03-20-WD6 (資訊引用於 中華民國110年西元2021年3月20日) by 湯偉晉 (WeiJin Tang)
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Source (資訊來源):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1944995/pdf/nihms17516.pdf
Info cited on 2021-03-20-WD6 (資訊引用於 中華民國110年西元2021年3月20日) by 湯偉晉 (WeiJin Tang)
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Neuroscience. Author manuscript; available in PMC 2007 Aug 10.
Neuroscience. 2007 Feb
9; 144(3): 991–1003.
Published online 2006 Dec 5. doi: 10.1016/j.neuroscience.2006.09.064
PMCID: PMC1944995
NIHMSID: NIHMS17516
PMID: 17150307
Depletion of Reduced
Glutathione Enhances Motor Neuron Degeneration in vitro and in vivo
Liying Chi,1 Yan Ke,2 Chun Luo,1 David Gozal,2 and Rugao Liu1,*
Author information Copyright and License information Disclaimer
1 Department of Anatomy and Cell Biology, University of North Dakota School of
Medicine, 501 N. Columbia Road, Grand Forks, ND 58202
2 Kosair Children Hospital Research Institute, Department of Pediatrics,
University of Louisville, 570 S. Preston St., Suite 204, Louisville, KY 40202
*Corresponding author: Rugao Liu, Ph.D., Associate Professor, Department of
Anatomy and Cell Biology, University of North Dakota School of Medicine, 501 N.
Columbia Road, Grand Forks, ND 58202, Telephone: (701)-777-2559, Fax:
(701)-777-2477, E-mail: ude.kadon.enicidem@uilr
Section Editor: Dr. Werner Sieghart
The publisher's final edited version of this article is available at
Neuroscience
Abstract (摘要)
The mechanism of selective and age-dependent motor neuron degeneration in human
amyotrophic lateral sclerosis (ALS) has not been defined and the role of
glutathione (GSH) in association with motor neuron death remains largely
unknown. A motor neuron-like cell culture system and a transgenic mouse model
were used to study the effect of cellular GSH alteration on motor neuron cell
death. Exposure of NSC34 motor neuron-like cells to Ethacrynic Acid (EA) or
L-Buthionine Sulfoximine (BSO) dramatically reduced the cellular GSH levels,
and was accompanied by increased production of reactive oxygen species (ROS)
measured by the DCF fluorescent oxidation assay. In addition, GSH depletion enhanced oxidative
stress markers, AP-1 transcriptional activation, c-Jun, c-Fos and HO-1
expression in NSC34 cells analyzed by a luciferase reporter, western blotting
and quantitative PCR assays respectively. Furthermore, depletion of GSH decreased mitochondrial function,
facilitated apoptosis inducing factor (AIF) translocation, cytochrome c
release, and caspase 3 activation, and consequently led to motor neuron-like
cell apoptosis. In an ALS-like transgenic mouse model overexpressing
mutant G93A-SOD1 gene, we showed that the reduction of GSH in the spinal cord
and motor neuron cells is correlated with AIF translocation, caspase 3
activation, and motor neuron degeneration during ALS-like disease onset and
progression. Taken together, the in vitro and in vivo data presented in the
current report demonstrated that decreased GSH promotes
multiple apoptotic pathways contributing, at least partially, to motor neuron
degeneration in ALS.
Introduction (簡介)
Amyotrophic lateral
sclerosis (ALS) is a fatal neurodegenerative disease that primarily affects
motor neurons in brain cortex, brainstem and spinal cord (Williams and
Windebank, 1991). The mechanisms underlying the selective and age-dependent motor neuron degeneration remain
largely unidentified, and effective
therapy for ALS is not yet available. Mutations of Cu,Zn-superoxide
dismutase (SOD1) gene cause
motor neuron degeneration and have linked to 2–5% of ALS cases (Rosen et
al., 1994; Rosen et al., 1993). Several potential mechanisms of motor neuron
degeneration in ALS have been proposed based on clinical studies, animal model
and cell culture system analyses. Increased oxidative stress, glutamate
toxicity, protein aggregation
and Cu/Zn cytotoxicity have all been suggested to contribute to motor neuron degeneration (Cleveland
and Rothstein, 2001; Li et al., 2003; Liu et al., 2002; Shaw et al., 2001; Shaw
and Eggett, 2000; Shibata et al., 2000). Of these, increased oxidative stress appears to be an early and sustained event in association with motor neuron death in ALS
(Bogdanov et al., 1998; Liu et al., 1998), although the specific mechanism
leading to oxidative damage on motor neurons remains to be defined. Oxidative stress can be
potentially increased by enhanced production of reactive oxygen species (ROS),
decreased antioxidants/antioxidant enzyme systems or a combination of both.
Glutathione (GSH), a tripeptide of γ-glutamylcysteinylglycine, is one of the
most abundant antioxidants in cells and tissues. Reduction of GSH enhances ROS production and promotes
oxidative damage. A previous study demonstrated increased
GSH binding in the
spinal cords of patients with sporadic ALS (Lanius et al., 1993), suggesting that GSH may play a role
in the pathogenesis of ALS. In a cell culture model, it has been shown
that expression of mutant SOD1 gene decreased cellular levels of GSH, suggesting the reduction in GSH bioavailability may
participate in the mutant SOD1-mediated motor neuron degeneration (Lee
et al., 2001).
GSH is the most abundant and
effective scavenger against ROS directly in mammalian cells. In addition, GSH is also a key
substrate for antioxidant enzymes that detoxify hydrogen peroxide and lipid
peroxide catalyzed by glutathione peroxidase. More recently, it has been demonstrated that GSH participates in cellular
signal transduction pathways, and modulates ionotropic receptor function
(Bains and Shaw, 1997; Grima et al., 2003; Janaky et al., 1993). GSH is synthesized in two
sequential enzymatic reactions catalyzed by γ-glutamylcysteine synthetase
(γ-GCS) and GSH synthetase. L-Buthionine Sulfoximine (BSO) is a selective inhibitor (選擇性的抑制劑) of γ-GCS. Exposure of cells to BSO
inhibits GSH synthesis and decreases intracellular levels of GSH. Thus,
BSO has been frequently used to study the role of GSH in association with
oxidative stress-induced neuronal cell and other cell death. On the other hand, because BSO does
not completely deplete mitochondrial and nuclear GSH, other agents,
including ethacrynic acid (EA)
have been used to effectively deplete cellular, mitochondrial and nuclear GSH
(Keelan et al., 2001; Rizzardini et al., 2003). Alterations in GSH synthesis, or in GSH pools, have been associated
with neuronal cell death
and mimic a variety of human neurodegenerative diseases, such as Parkinson’s disease (Bharath
et al., 2002; Jha et al., 2000; Mytilineou et al., 2002; Paik et al., 2003), Alzheimer’s disease (Adams,
Jr. et al., 1991; Cecchi et al., 1999; Janaky et al., 1999; Karelson et al.,
2002) and Schizophrenia
(Do et al., 2000). Nevertheless, the role of GSH in the pathogenesis of motor
neuron degeneration in ALS remained largely undefined. To this end, we have
focused on a cell culture system and an ALS-like transgenic mouse model to study the effect of GSH on
motor neuron cell death. We showed that reduction of intracellular GSH increases oxidative
stress, decreases
mitochondrial function,
activates multiple apoptotic pathways, and consequently contributes to motor
neuron degeneration in
vitro and in vivo.
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