fos als '13 poster (final)
TRANSCRIPT
Effects of Cerium Oxide Nanoparticles on Disease Progression in a Transgenic Mouse Model of Amyotrophic Lateral Sclerosis
A. S. Gardner1, J. D. Pusey1, M. K. Hamel3, J. A. Foster-Moore1, M. U. Prajapati1, K. Heckman2, W.E. DeCoteau1,3 and J.S Erlichman1,2
Program in Neuroscience1 and Departments of Biology2 and Psychology3, St. Lawrence University, Canton NY
IntroductionOxidative stress is a factor in the onset and progression of many neurodegenerative diseases. Oxidative stress occurs when reactive oxygen species (ROS) accumulate and damage cellular structures. Antioxidants can act therapeutically to reduce tissue death and increase survival. In this study we examined the neuroprotective effects of ceria nanoparticles on survival interval and motor decline in a transgenic murine model of Amyotrophic Lateral Sclerosis (ALS).
A glycine to alanine substitution at position 93 of the SOD1 protein (G93A ) reflects characteristics of familial ALS, and thus expression of this SOD1 mutation has been implemented as a mouse model of ALS through adopting a toxic gain of function. This gain of function induces the upregulation of SOD1 which becomes toxic, increasing the production of hydroxyl radicals from hydrogen peroxide precursors. Disease onset is spontaneous and usually occurs around 100-120 days of age, life expectancy is normally two to four weeks beyond onset of observable clinical symptoms.
G93A Model
Normal SOD activitySOD ↑H2O2Superoxide anion Catalase
activity ↑H2O and O2
Behavioral Testing and Clinical Scores
Cerium Oxide NanoparticlesCerium oxide nanoparticles (2.5nm) are made up of 80 atoms in the form of a lattice structure that have oxidation-reduction properties believed to scavenge free radicals by trapping them in their oxygen vacancies and shuffling them between the +3 and +4 states. Due to their ability to scavenge free radicals, it is hypothesized that cerium oxide could reduce motor degeneration and neuron loss resulting from the production of free radicals.
Past Experimental Paradigm
Table 1. ALS clinical scale
ConclusionThe results of this study indicate CeO2 NP treatment :• increased survival in the G93A mouse model of ALS. The effect was more
pronounced in female mice.• improved “quality of life” in the G93A mouse model of ALS as measured by body
weight and grip strength changes following disease onset.• shows promise as a treatment for familial ALS and other human disorders
related to oxidative stress.
CeO2 Nanoparticle TreatmentFollowing disease onset, all mice (23 males, 33 females) were given semi-weekly tail injections of either saline or CeO2 NPs (20 mg/kg) mixed in saline. Drug treatment and daily hanging wire testing, clinical scoring, and body weight measurements were carried out until animals reached the disease endpoint defined as scoring <2.5 on the clinical score or losing more than 20% drop of baseline body weight.
AcknowledgmentsWe would like to Liz McDougall, Abby Korn and Alyssa Couse for their help with animal care, Bonnie Erlichman and Krista Bray, for injections; Mike Temkin, for genotyping and Cerion Energy (Rochester, NY) for providing the nanoparticles.
ALSALS is a neurodegenerative disease characterized by muscular atrophy; initially hindering limb movement and ability to swallow, progressing to full body paralysis. Most familial cases of ALS are related to a mutation to the superoxide dismutase 1 (SOD1) gene, a natural catalytic antioxidant, which results in increased of free radicals, such as superoxide. Treatment for ALS is currently aimed at slowing disease progression and targets symptoms of the disease after onset.
Present Experimental Paradigm
Treatment Group
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y to
Fal
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P = 0.687
(Males)
(Females)
Treatment Group
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P = 0.238
Pre-Disease Hanging Wire Performance
Hanging Wire Performance (Males)
Days Following Disease Onset0 5 10 15 20 25
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Control Drug
Hanging Wire Performance (Females)
Days Following Disease Onset0 5 10 15 20 25
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ControlDrug
* * * * ** ***** *
** **** * * * ** * *
n=23
n=33
Fig 3 (left). Female mean latency to fall as a function treatment group (control vs drug) and day following disease onset. Fig 3 (right). Overall male mean latency to fall (s) as a function treatment group (control vs drug).
Hanging Wire Performance (Males)
Days Following Disease Onset0 5 10 15 20 25
Mea
n La
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y To
Fal
l (s)
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20
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Control Drug
Hanging Wire Performance (Females)
Days Following Disease Onset0 5 10 15 20 25
Mea
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l (s)
0
10
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ControlDrug
* * * * ** ***** *
** **** * * * ** * *
n=23
n=33
Fig 2 (left). Male mean latency to fall (s) as a function treatment group (control vs drug) and day following disease onset. Fig 2 (right). Overall male mean latency to fall (s) as a function treatment group (control vs drug).
Fig 4. Percent survivors for males (left) and females (right) as a function of treatment (control vs drug) and days after disease onset. Kaplan-Meyer regression analyses indicate a significant increase in survival trajectory for females but not males.
Fig 1. Mean male and female pre-disease onset hanging wire performance.
Results
Prior to disease onset all mice were trained (males at ~ age 85 days; females at ~ age 100 days) daily on the hanging wire task that measures grip strength. Latency to fall (180s max) from an elevated and inverted wire floor was measured. Two consecutive decreases from baseline performance was used to mark “disease onset.” Following disease onset animals were assigned to treatment groups and were scored for clinical symptoms (table 1).
Score Symptoms5.0 Normal movement; no paralysis
4.5 Clumsy gait
4.0Limping or dragging of at least 1 hind limb
3.01 hind limb is extended (not spontaneously flexed)
2.5 Both hind limbs extended
2.0 Bilateral hind limb failure and paresis in 1 forelimb
1.0Animal cannot right itself within 30 seconds