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Mechanisms of Cell Death in Spinal Muscular Atrophy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01754441
Recruitment Status : Unknown
Verified August 2015 by Matthew E. R. Butchbach, Ph.D., Nemours Children's Clinic.
Recruitment status was:  Enrolling by invitation
First Posted : December 21, 2012
Last Update Posted : August 24, 2015
Information provided by (Responsible Party):
Matthew E. R. Butchbach, Ph.D., Nemours Children's Clinic

Brief Summary:
Spinal muscular atrophy is a genetically based disease that affects motor neurons in the spinal cord and leads to muscle wasting and weakness. The gene found to be responsible for the underlying disease is called the SMN or survival motor neuron gene. Individuals with SMA are either missing a copy of the gene or have a mutation in the gene. Although the gene has been identified, how it actually causes the motor neurons to die and leads to muscle wasting and weakness is not completely understood. The investigators have found that skin cells from children with SMA tend to be more susceptible to cell death when exposed to cell death inducing agents. In this protocol, The investigators wish to study the mechanisms by which these cells die when exposed to these agents and how this may be related to the gene defect and the disease.

Condition or disease
Spinal Muscular Atrophy

Detailed Description:
Spinal muscular atrophy (SMA) is a neuromuscular disease characterized by degeneration of motor neurons and progressive muscle atrophy. The disease is one of the most common genetic causes of infant death. The gene responsible for SMA, survival motor neuron (SMN), exists in humans as two nearly identical copies (SMN1 and SMN2). Only deletion or mutation(s) of the telomeric copy of the gene (SMN1) causes the disease. The SMN protein has been known to function in assembly of the RNA splicing complex, however, the mechanism(s) by which SMN-deficiency causes cell death in SMA are not clear. The long-term goal is to understand the mechanism(s) of motor neuron death in SMA and develop a means of prevention. SMN protein has been reported to have some survival promoting functions in cultured cells. Preliminary studies show that skin fibroblasts from SMA patients are more sensitive to certain death promoting stimuli than control fibroblasts. The investigators hypothesize that the SMN protein is directly involved in cell survival and that loss of this survival function of SMA results in motor neuron death in SMA. The investigators will use fibroblasts from SMA patients, fibroblasts from controls without SMA, motor neuron-like cell lines (such as NSC-34) and rodent primary motor neuron cultures as model systems to test our hypothesis. The investigators will determine the effect of expression of SMN protein in regulating cell death of SMA fibroblasts. The investigators will further investigate the role of SMN in neuronal cell survival. Finally, the investigators will determine biological pathway(s) of SMN-mediated cell protection. Results from the proposed studies will provide insight into the mechanism(s) by which SMN protects cells from death and how a decrease in SMN function leads to the SMA phenotype. Ultimately, the obtained information could lead to develop therapeutic strategies for SMA.

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Study Type : Observational
Estimated Enrollment : 50 participants
Time Perspective: Prospective
Official Title: Mechanisms of Cell Death in Spinal Muscular Atrophy
Study Start Date : May 2008
Estimated Primary Completion Date : December 2017
Estimated Study Completion Date : December 2017

Primary Outcome Measures :
  1. SMN localization in SMA fibroblasts [ Time Frame: up to 2 years ]
    Established fibroblast lines from SMA patients will be immunolabeled with antibodies directed against SMN and examined for changes in the nuclear localization of SMN in gems.

Secondary Outcome Measures :
  1. SMN isoform mRNA levels [ Time Frame: up to 2 years ]
    The levels of full-length SMN and SMNdelta7 (lacking exon 7) mRNA transcripts will be measured using quantitative PCR.

  2. Protein levels of putative SMA phenotypic modifiers [ Time Frame: up to 2 years ]
    The levels of previously identified modifiers of SMA clinical phenotype (i.e. plastin-3 and ZPR-1) will be examined by immunoblot.

  3. cell viability in response to DNA damaging agents [ Time Frame: up to 2 years ]
    The responsiveness of SMA fibroblasts to DNA damaging agents such as camptothecin, etoposide, bleomycin and actinomycin D will be measured using cell viability assays

  4. SMN protein levels [ Time Frame: up to 2 years ]
    SMN protein levels will be measured by immunoblot.

  5. cell viability in response to cell death-inducing agents [ Time Frame: up to 2 years ]
    The responsiveness of SMA fibroblasts to cell death-inducing agents such as staurosporine, tunicamycin and hydrogen peroxide will be examined using cell viability assays.

  6. SMN2 copy number [ Time Frame: up to 2 years ]
    SMN2 copy number will be determined by quantitative PCR of genomic DNA isolated from established fibroblast lines.

Biospecimen Retention:   Samples With DNA
Skin biopsy specimens

Information from the National Library of Medicine

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Ages Eligible for Study:   up to 21 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
This study will enroll Children with Spinal Muscular Atrophy (SMA)

Inclusion Criteria:

  • Diagnosis of SMA confirmed by neurologist

Exclusion Criteria:

  • Not seen as a patient at a participating Nemours facility

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01754441

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United States, Delaware
Alfred I. duPont Hospital for Children
Wilmington, Delaware, United States, 19803
United States, Florida
Nemours Children's Specialty Care, Jacksonville
Jacksonville, Florida, United States, 32207
Nemours Children's Hospital
Orlando, Florida, United States, 32827
Sponsors and Collaborators
Nemours Children's Clinic
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Principal Investigator: Matthew ER Butchbach, Ph.D. Nemours Biomedical Research

Publications of Results:
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Responsible Party: Matthew E. R. Butchbach, Ph.D., Research Scientist, Nemours Children's Clinic Identifier: NCT01754441     History of Changes
Other Study ID Numbers: 82008
First Posted: December 21, 2012    Key Record Dates
Last Update Posted: August 24, 2015
Last Verified: August 2015
Keywords provided by Matthew E. R. Butchbach, Ph.D., Nemours Children's Clinic:
Spinal Muscular Atrophy
Motor Neuron Abnormalities
Additional relevant MeSH terms:
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Muscular Atrophy
Muscular Atrophy, Spinal
Pathological Conditions, Anatomical
Neuromuscular Manifestations
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Spinal Cord Diseases
Central Nervous System Diseases
Motor Neuron Disease
Neurodegenerative Diseases
Neuromuscular Diseases