In the mutant SOD1-G93A (mutSOD1) mouse model of amyotrophic lateral sclerosis (ALS), the mutated form of SOD1 selectively binds and aggregates with Bcl-2 in spinal cord mitochondria. In this study we will test the hypothesis that the portion of mutSOD1 localized in spinal cord mitochondria must partner with Bcl-2 to manifest toxicity. We will also define the consequences of the mutSOD1/Bcl-2 aberrant binding on the spinal cord mitochondria ionic conductances and bioenergetics. By adapting and applying the patch-clamp electrophysiological technique (mito-attached configuration) to integral, neuronal and non-neuronal spinal cord mitochondria isolated from the double transgenic ALS mouse SOD1-93A: mitoCFP, we will systematically characterize the conductances of the outer mitochondrial membrane (OMM) throughout the different stages of disease, determining whether this mitochondria phenotype is specifically altered as the disease progresses. We are proposing three specific aims.
In aim #1 we will study in vitro mutSOD1- mediated toxicity at the cellular and mitochondrial levels and its dependence on Bcl-2.
In aim #2 we will study in situ the biophysical properties of neuronal and non-neuronal mitochondria isolated from the spinal cord of double transgenic SOD1-G93A: mitoCFP mice carrying fluorescently (cyan) tagged blue neuronal mitochondria. Furthermore, we will study the effect of mutSOD1 proteins on mitochondria outer membrane channels using mitochondria isolated from cells expressing Bcl-2 versus cells lacking Bcl-2 and transgenic mice.
In aim #3 we will test in vivo the hypothesis that the binding of mutSOD1 to Bcl-2 is required for motor neuron toxicity and a determinant of the ALS phenotype by generating SOD1-G93A:Bcl-2(-/-) mice and comparing the disease phenotype of these mice to the SOD1-G93A mice in which Bcl-2 was not ablated. By developing these aims, we will understand whether by interacting with the anti-apoptotic protein Bcl-2, mutSOD1 leads to mitochondria dysfunction and the immediate relevance of this aberrant mechanism to motor neuron degeneration in ALS mice.

Public Health Relevance

Amyotrophic lateral sclerosis (ALS;a.k.a. Lou Gehrig's disease) is the most common adult motor neuron disease. The disease is characterized by the death of motor neurons in the spinal cord and motor cortex. This leads to spasticity, hyper-reflexia, general weakness and muscle atrophy. Failure of respiratory muscles is generally the fatal event, occurring within 1 - 5 years after the onset of the first symptoms. The overarching goal of this proposal is to shed light on the mechanisms of motor neuron death using transgenic mice model of ALS. The objective of our proposal is to study the disease mechanisms focusing on mitochondria of the spinal cord of these mice. Mitochondria are sub-cellular organelles and the main source of energy production in the body. They play a pivotal role in maintaining neuronal cell alive. A pathology-driven impairment of these organelles may shift the balance between life and death and lead to neuronal degeneration.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
Project #
Application #
Study Section
Clinical Neuroplasticity and Neurotransmitters Study Section (CNNT)
Program Officer
Gubitz, Amelie
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Thomas Jefferson University
Schools of Medicine
United States
Zip Code
Tan, Wenzhi; Pasinelli, Piera; Trotti, Davide (2014) Role of mitochondria in mutant SOD1 linked amyotrophic lateral sclerosis. Biochim Biophys Acta 1842:1295-301
Tan, Wenzhi; Naniche, Nicole; Bogush, Alexey et al. (2013) Small peptides against the mutant SOD1/Bcl-2 toxic mitochondrial complex restore mitochondrial function and cell viability in mutant SOD1-mediated ALS. J Neurosci 33:11588-98
Guareschi, Stefania; Cova, Emanuela; Cereda, Cristina et al. (2012) An over-oxidized form of superoxide dismutase found in sporadic amyotrophic lateral sclerosis with bulbar onset shares a toxic mechanism with mutant SOD1. Proc Natl Acad Sci U S A 109:5074-9
Pedrini, Steve; Sau, Daniela; Guareschi, Stefania et al. (2010) ALS-linked mutant SOD1 damages mitochondria by promoting conformational changes in Bcl-2. Hum Mol Genet 19:2974-86
Fieni, Francesca; Parkar, Anjum; Misgeld, Thomas et al. (2010) Voltage-dependent inwardly rectifying potassium conductance in the outer membrane of neuronal mitochondria. J Biol Chem 285:27411-7