Current Research: ALS
- Zebrafish as a Model Organism for ALS
- Computational Analysis of SOD1
- Stem Cell Initiative
- Innovative Treatment for ALS Using VEGF
- The Role of Environmental Toxins in ALS
Zebrafish as a Model Organism for ALS
Zebrafish as a model organism provide many advantages over mouse and rat models for studying disease causes and for discovering new therapies. Zebrafish are vertebrate organisms that are very similar to mammals in their development and physiology, but they develop very quickly. Large numbers of embryos are obtained on a weekly basis and they are fertilized externally. Zebrafish are easy to observe early in development because they are transparent, and potential therapies can be tested on zebrafish by simply adding the compounds to the water. Lastly, zebrafish genes can be easily manipulated to create disease models.
The ALS zebrafish model is generated by expressing mutant SOD1 in the embryos, a mutation associated with familial ALS. These mutant SOD1 zebrafish have motor neurons with observable defects. Using zebrafish as a model organism for ALS will allow us to understand the effects of mutant SOD1 on motor neurons and identify changes in the motor neurons that could be used to diagnose the disease earlier. Zebrafish will also enable us to screen large numbers of potential therapeutic factors, and combinations of these potential therapeutic factors, to identify new beneficial treatments for ALS.
Computational Analysis of SOD1
Familial amyotrophic lateral sclerosis (fALS) is caused by mutations of the Cu-Zn superoxide dismutase 1 (SOD1) protein. SOD1 maintains its antioxidant activity under these fALS causing mutations, thus suggesting that the mutations introduce a new, toxic, function. We developed a pair of complementary computational methods for elucidating a component of the toxic mechanism.
The first method is based on the static conformation of the healthy, wild type (WT) form and indicates an inherent network of connectivity within the structure. This network is a foundation which allows for internal structure communication. The second method identifies the accessible motions of the WT and mutant structures. A comparative analysis of these motions reveals motions that are preferred by the mutant structures compared to the WT.
Our hypothesis is that the preferred motions induced by the disease causing mutations are able to communicate across the structure and introduce a toxic function.
Stem Cell Initiative
Stem cells give rise to all cell types and are the beginning building blocks of our body. As adults, populations of these cells are low. The potential of stem cells to help us resist or recover from disease as well as injury is a new and exciting area of research. A hallmark feature of ALS is the loss of nerve cells that control the ability to speak, breathe and move their arms and legs. Patients with ALS retain their ability to think, understand and sense their environment; they are fully aware each day as they gradually lose their ability to move and their independence. Stem cell technology offers a unique opportunity to support and maintain the health of nerve cells in patients with ALS.
In January of 2007, we formed an exciting collaboration with Dr. Martin Marsala at the University of California San Diego and Neuralstem Inc. to directly inject stem cells into the spinal cord of ALS rats. Our preliminary results show these rats retain their ability to move and live much longer than rats that do not receive stem cell therapy. These transforming data lead us to begin a series of spinal cord stem cell injections in ALS rats. We secured the funding to establish an ALS rat colony, purchase stem cells and support the necessary personnel to complete the injections and follow the clinical outcomes of the ALS rats. However, we do not yet have the funding needed to complete the anatomical and molecular analyses of the spinal cords and understand how the stem cells are enhancing spinal cord function. We must understand how the stem cells work if we are to translate this therapy into patients with ALS. Our questions are: Are the stem cells becoming new nerve cells or new supporting glial cells? What is the optimum number of stem cells to inject into the spinal cord and when? Are these potential nerve cells functional i.e. is there evidence of nerve to nerve contact? What types of proteins, especially neurotransmitters, do the stem cells/nerve cells produce? Will the stem cells form long connections i.e. connect to sick muscles? We have the tools to answer these questions. We need the person power.
Innovative Treatment for ALS using VEGF
This study, if positive, will provide the fundamental basis for the use of stem cells in the treatment of neurological disorders such as ALS.
Dr. Andrea Vincent & Dr. Bhumsoo Kim
Vascular endothelial growth factor (VEGF) controls new blood vessel growth. In the nervous system, however, it also supports the growth and survival of neurons. Mice lacking the ability to increase their VEGF levels experience a condition which appears almost identical to amyotrophic lateral sclerosis (ALS) in humans. In addition, studies of VEGF in 600 individuals with ALS and 1,000 case-controls have shown that decrease in VEGF levels can increase the risk of developing ALS by nearly double. These findings suggest that VEGF may eventually be used as a therapy for ALS. One practical problem with using VEGF as a therapy in patients is that cells produce multiple types of VEGF, and a combination of these types is required for VEGF to produce effects. To get around this problem we are working with Sangamo Biosciences, Richmond, CA to develop a new way to increase VEGF activity in the nervous system using gene therapy.
This project has three primary goals:
- Examine the effects of VEGF on motor neurons in culture.
- Test the effect of our gene therapy approach on production and bioactivity of VEGF.
This study, if positive, will provide rationale to define the theraputic potential of VEGF as a treatment for ALS. A grant has been submitted to the National Institutes of Health, R01 NS 051705 entitled "VEGF as a treatment for ALS."
The Role of Environmental Toxins in ALS
ALS (amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease) is a disease characterized by the deterioration of motor neurons in the brain and spinal cord. Approximately 10% of ALS cases are due to genes inherited within families. The cause of the remaining 90% of ALS cases is still unknown. No treatment is currently available to significantly slow or halt the progress of this disease. We believe that a genetic predisposition combined with specific lifestyle elements (e.g., exposure to environmental toxins, athletic/physical exertion, or diet) contribute to the onset of ALS. We are currently addressing this question in a combination of ways:
CELLULAR STUDIES
First, through cellular studies, we are attempting to identify classes of toxins in the environment that affect the nervous system (neurotoxins), and mediate motor neuron injury. Neurotoxins produce cellular damage in a variety of ways, all of which are dangerous to cells. By screening FDA approved drugs in our primary motor neuron models, we test the hypothesis that specific classes of neurotoxins create motor neuron injury.
ANIMAL STUDIES
Second, by studying a mouse model of clinical ALS, we investigate numerous aspects of the disease. We are examining the effects of exercise stress and distinct classes of neurotoxins on motor neurons. In addition, we hope to identify the genes that account for the variations between genetically similar mice that inhabit the same environment. Understanding which genes cause the differences would provide tremendous insight into the injury of motor neurons, as well as provide potential targets for therapy. These goals are all designed to determine whether neurotoxins or exercise stress worsen motor neuron injury.
POPULATION STUDIES
Finally, we must conduct a comprehensive study of ALS in the population. Although it would seem an obvious initial step, too little has been done to compile information about ALS cases in the state of Michigan and elsewhere. The aim of such a study is to determine the prevalence of ALS, examine its causes, identify possible common factors, and study a potential correlation between ALS and toxic exposure in Michigan. This project is the first attempt to systematically examine ALS cases and determine whether any clusters of the disease exist that would indicate specific environmental causes. The information gathered from this project will prove to be a valuable tool when used in conjunction with our laboratory research. A study of this type will also assist in the improvement of the public health response to ALS.
This study, if positive, will provide rationale to conduct an epidemiological study on the cause/effect of toxic exposure in ALS in MI. A grant has been submitted to the National Institutes of Health, NIH RO1 entitled "The role of environmental contaminants in ALS."
