The 2003 Parkinson's Unity Walk Funds Research Grants
Through the generous support of its corporate sponsors, 100% of all donations made to the Parkinson's Unity Walk are distributed among the major U.S. Parkinson's disease foundations for Parkinson's disease research. The foundations include: (1) the American Parkinson's Disease Foundation; (2) the National Parkinson's Foundation; (3) the Parkinson's Action Network; (4) the Parkinson's Disease Foundation; (5) the Michael J. Fox Foundation for Parkinson's Research; (6) The Parkinson Alliance; and (7) the Parkinson's Institute.
We are excited to share with you information about the following grants —all of which are made possible from 2003 Parkinson's Unity Walk distributions. In November 2004, updates to several grants were provided to us. Those updates are indicated below in red.
1. The American Parkinson Disease Association, Inc. is using its distribution to fund:
Grant to: Gregory A. Petsko, Ph.D.
Project Title: Structural and Functional Studies of DJ-1, The Protein Whose Gene is Mutated in Autosomal Recessive Early-Onset Parkinson’s Disease
The investigator hypothesizes that the death of Dopanergic neurons in PD programmed cell death (apoptosis) caused by abnormal build-up of oxidatively damaged, misfolded proteins in the cells of the substantia nigra. He further hypothesizes that all familial Parkinson’s Disease will be due to loss of function of protein involved in either protection against oxidative stress or proteolytic degradation of stress-damaged proteins, and that sporadic PD is due to somatic mutations in genes in the same pathways. This model rests on the observations that DJ-1 appears to be a protein involved in oxidative stress response, that the PD-associated mutations would abolish that function, and finally that cells in the quiescent state, which include dopanergic neurons, are more sensitive that proliferating cells to oxidative damage because they cannot dilute out or repair damaged proteins as efficiently as can proliferating cells.
November 2004 Project Update:
Mutations in NJ-1, a human gene with homologues in organisms from all kingdoms of life, have been shown to be associated with autosomal recessive, early onset Parkinson's disease (PARK7). We report here the three-dimensional structure of the DJ-1 protein, determined at a resolution of 1.1 A by x-ray crystallography. The chain fold of DJ-1 resembles those of a bacterial protein, PfpI, that has been annotated as a cysteine protease, and of a domain of a bacterial catalase whose role in the activity of that enzyme is uncertain. In contrast to PfpI, a hexameric protein whose oligomeric structure is essential for its putative proteolytic activity, DJ-1 is a dimmer with complete different intersubunit contacts. The proposed catalytic triad of PfpI is absent from the corresponding region of the structure of the DJ-1, and biochemical assays fail to detect any protease activity for purified DJ-1. A highly conserved systeine residue, which is catalytically essential in homologues of DJ-1, shows an extreme sensitivity to radiation damage and may be subject to other forms of oxidative modification as well. The structure suggests that the loss of function caused by the Parkinson's-associated mutation L166P in DJ-1 is due to destabilization of the dimmer interface. Taken together, the crystal structure of human DJ-1 plus other observations suggest the possible involvement of this protein in the cellular oxidative stress response and a general etiology of neurodegenerative diseases.
Grant to: Mona J. Thiruchelvam, University of Rochester
Project Title: Neonatal Pesticide Exposure and Parkinson's Disease
The goal of this proposal is to determine whether disruptions of antioxidant defense systems underlie both the permanent neurotoxicity arising from development exposure to the herbicide paraquat and the fungicide maneb alone and in combination and the enhanced vulnerability following adult re-challenges with these pesticides. Our evidence for progressive effects following developmental exposures to date relies on behavioral endpoints coupled with our observations that permanent reductions in locomotor activity have always occurred in conjunction with nigral TH neuron loss in previous studies as well as the increased vulnerability of adults re-challenged with pesticides.
November 2004 Project Update:
The studies of this grant examine the hypothesis that combined PQ and MB exposure during critical periods of development would result in an additive or even synergistic consequence based on the premise that exposure to an individual chemical may be insufficient to induce overt effects, whereas multiple exposures, by provoking changes concurrently at multiple different target sites of the nigrostriatal dopamine system, would impair the operation of homeostatic defense mechanisms leading to neuronal cell death.
Mice at 25 days of age (6 days after exposure) evaluated for changes in locomotor activity had no significant changes in locomotor activity., a significant decrease in locomotor activity at 6 weeks of age was apparent in the group exposed to PQ + MB, with all the other groups exhibiting activity levels similar to that of controls. At 3 months of age, the PQ+Mb grop showed behavioral changes that were worse compared to the earlier time-points, indicating progressive worsening of locomotor activity.
When dopamine level were determined using HPLC analysis in the striatum, at 25 days of age there was no significant difference between the treatment groups although there was a tend towards a decrease in dopamine levels in the PQ+Mb treated group. This could be due to the presence of pharmacological effects of the exposures, reflected in the striatal dopamine levels. At 7 weeks of age, a significant decrease in striatal dopamine levels were observed in the group that was treated with PQ+MB only, with the PQ and the Mb alone groups showing dopamine and metabolite levels similar to that of controls. This decrease in the PQ+Mb group is still apparent at 3 months of age, although a trend towards a further decline was observed but not statistically significant. Compensatory changes at the level of the terminals may prevent a further decline of striatal dopamine levels.
Stereological counts of tyrosine hydrowylase positive (TH+) and non-TH neurons in the substantia nigra pars compacta (SNpc). At 25 days of age, there is no difference between the treatment groups in the number of TH+ or TH- neurons in the region. However, at 6 weeks of age there is a significant (15%) loss of dopaminergic neurons in the SNpc, again only in the PQ+Mb treated group. This indicates that the neurons are dying over time after cessation of exposure. At 3 months of age a further loss of dopaminergic neurons is observed in the PQ+Mb group (25%). The difference from 6 weeks to 3 months, although only 10%, was statistically significant. This supports our initial hypothesis that developmental exposure to these compounds, especially in combination, results in progressive loss of dopaminergic function in the nigrostriatal pathway. The TH+ neurons counted in the ventral tegmental area (VTA) indicated no significant difference between the treatment groups at any of the time-points analyzed thus far (25 days, 6 weeks and 3 months of age).
It was hypothesized that this decline is a result of increased oxidative stress as a consequence of exposure to PQ+Mb and determined the levels of lipid peroxidation and glutathione at these time-points following exposure. There was a significant increase in lipid peroxidation levels at 24 days of age in all treatment groups, with the greatest increase observed in the PQ+Mb treated group. There as a potentiated increase in lipid peroxidation levels in the PQ+Mb group compared to either PQ or Mb alone treated animals. At 6 weeks and 3 months of age, there was still an elevated level of lipid peroxidation, with significant increases observed only in the PA+Mb group at all the 3 time points analyzed. GSH levels were also diminished in the PQ and Mb alone groups at 25 days of age, with levels returning to controls levels by 3 months of age.
Data thus far indicates a progressive loss of dopaminergic neurons of the SNpc, with the VTA neurons being spared. Similar behavioral correlation was also observed, although changes in striatal dopamine levels don't follow the same trend. The selectivity of the nigrostriatal dopaminergic system to the effect of these toxicants is in support of our previous observations.
2. The National Parkinson Foundation is using its distribution to fund the following:
Grant to: Luigi Zecca, MD
Project Title: The Role of Neuromelanin in Glial Activation and Neuronal Damage in Parkinson disease.
There may be two parts to why PD worsens over time. Something, as yet unknown, causes pigmented nerve cells in a region of the brain called the substantia nigra to die. Once, however, a nerve cell dies it releases the pigment inside it into the space surrounding the cell. This activates the surrounding glial or support cells resulting in inflammation. This may result in further damage to the already compromised nerve cells. This study will show if the glial or support cells that have been activated actually cause further damage. If they do, this will lead to new insights into how to halt the progression of PD.
November 2004 Project Update:
Project Update: In the substantia nigra of PD patients a proliferation of microglial cells surrounding neuromelanin granules was observed thus indicating a condition of chronic inflammation in PD. In this project the effect of human neuromelanin and synthetic neuromelanins will be investigated on glial culture. The effect of neuromelanin on neuronal vulnerability will be observed in neuronal cultures of rat midbrain.
Substantia nigra samples were collected during autopsies of normal subjects and neuropathologically evaluated. Neuromelanin has been isolated from these tissues according to previously reported procedure with some modifications.
In order to establish the molecular specificity of neuromelanin in inducing microglia activation of the following modified neuromelanin were prepared:
a) Neuromelanin with partially truncated peptide chain by incubation with proteinase-K
b) NM with low iron content by treatment of neuromelanin with EDTA
c) One synthetic melanin by auto oxidation of dopamine and cysteine and one synthetic melanin by tyrosinase oxidation of dopamine plue cysteine.
The other experiments, we examined the effect of neuromelanin in microglia/astrocyte culture. A range of neuromelanin levels, and gold particles used as inert controls, were deposited on cortical astrocytes, and microglia observed and counted over the course of one week. We found that all of the microglia were "activated" due to their immunolobel for differentiation marker, regardless of the presence of the pigment: this may be a function of the culture system. While we observe, to date, a similar proliferation of the microglia under all condition, we still observe marked effects due to the presence of neuromelanin. When neuromelanin is present, we observe that the microglia move towards the substance, surround it and ingest it: in fact, particles of the pigment are easily observed within these cells.
We are currently taking time-lapse videos of the microglia locomotion and phagocytosis of the neuromelanin to demonstrate and measure this phenomena. In the coming year, we will repeat and extend the experiments on the number of microglia, as we suspect that those exposed to neuromelanin die following phagocytosis. We also not that while neuromelanin may not exacerbate microglia number under these conditions, it may induce release of cytokines and other factors, and we will analyze the media under these same experimental conditions to ascertain this.
These are only preliminary results and the project is continuing with the final purpose to see whether neuromelanin can induce neuronal degeneration in cell culture and drugs can eventually block such a process.
Grant to: David Park, Ph.D.
Project Title: FAS and Parkinson disease
It’s not yet known why the dopamine containing nerve cells in the substantia nigra of patients with PD are singled out to die prematurely. It is likely that several processes are involved. Among them are energy depletion, free radical damage, and oxidative stress. Although the process may be different, the final common pathway may be activation of a cell "suicide" program. Among the genes that regulate the "suicide" program is a gene called Fas. This study will look at the role of Fas in the death of dopamine nerve cells. This may lead to novel ways of preventing or limiting the damage to dopamine nerve cells.
November 2004 Project Update:
The goal of this project was to determine whether JNK/C-Jun stress activated pathway might lead to upregulation of Fas in and MPTP model of PD. We also proposed to examine whether this pathway was required for death of dopamine neurons in the model.
We report that systemic MPTP increased nigral Fas expression and mice lacking Fas displayed attenuated SNc dopaminergic loss and microglial activation in response to MPTP. As well, Fas induction was blocked by expression of dominant negative c-Jun which also protected dopamine neurons from MPTP-induced damage. Taken together, these data suggest the critical nature of the c-Jun-Fas signaling pathway in MPTP-induced neuronal loss. While critical for degeneration of the soma, Fas deficiency did not significantly prevent the loss of terminal fibers within the striatum or normalize the elevation of the postsynaptic activity marker Delta FosB induced by denervations. Interestingly, Fas deficient mice displayed a preexisting reduction in the striatal dopamine levels and locomotor behavior when compared to wild type mice. Despite the reduction of the Striatal terminals, dopamine levels were not further reduced by MPTP treatment in mutant mice, raising the possibility of a compensatory response in basal ganglia function in Fas deficient mice.
The National Parkinson Foundation is also joining The Parkinson's Institute in funding the following:
Grant to: Dr. Lee He-Jin
Project Title: Role of autophagic lysosomal pathway in the degradation of alpha synuclein aggregates.
The protein alpha synuclein is important for the integrity and normal functioning of the dopamine cells in the substantia nigra. It is believed that if molecules of alpha synuclein are mis-shapen can become toxic, poisonous, to the cell. Such mis-shapen molecules may be removed by a "clearing" system in the cell that centers on a group of particles called lysosomes. It is believed that if this "clearing" system isn’t working properly then mis-shapen aggregates of alpha syncuclein accumulate and "poison" the cell. This study will look at the ability of the lysosomes to clear such mis-shapen aggregates of alpha synuclein in the tan.
November 2004 Project Update:
In this study, we have established a human neuroblastoma model to study the effect of DA on a-syn aggregation. Using various reagents to modulate DA levels in cells, we have shown that increased DA levels promote a-syn aggregation, and the aggregates are increased in membranes but not in the cytosol. Further fractionation of these membrane compartments demonstrated that the DA-induced a-syn aggregation is limited to DA-containing vesicles. Our previous study has shown that a-syn in membrane fractions, total membrane or crude synaptic vesicles, aggregated more rapidly when compared with cytosolic a-syn. The present study confirms that a-syn aggregation occurs initially in the membrane fraction in cells and that the increase in vesicular DA levels may enhance the aggregation propensity of a-syn. These results may explain the selective vulnerability of DA neurons to cytotoxic effects of a-syn, which may be due to membrane destabilization of a-syn aggregation. The elucidation of detailed mechanisms of how a-syn aggregation in DA-containing vesicles affect its cellular function, including synaptic transmission, would lead us to better understanding of the pathogenesis of PD.
3. Parkinson's Action Network (PAN), founded in 1991, is the unified education and advocacy voice of the Parkinson's community, fighting for a cure. Through education and interaction with the Parkinson's community, scientists, lawmakers, opinion leaders, and the public at large, PAN works to increase awareness about Parkinson's disease and advocates for increased federal support for Parkinson's research.
PAN also provides the information and resources necessary to empower people with Parkinson's disease to act on their own behalf and gain a greater sense of control over their health and their future. For more information on PAN, please see its website at www.parkinsonsaction.org.
4. Parkinson’s Disease Foundation is using its distribution to fund the following:
Grant to: Malu G. Tansey, Ph.D.
Project Title: Adipose-Derived Adult Progenitor Cells with Neurogenic Potential: An alternate Tissue Source for Parkinson's Disease Transplantation Therapies
In the search for alternative sources of stem cells, groups have identified adult brain and bone marrow stromal cells that they hope can be differentiated into neurons. The latest source is adult adipose (front fat)tissue that Dr. Malu Tansey (University of Texas, Dallas) thinks can be coerced into becoming neuronal tissue with the help of appropriate trophic-factor support. She will perform these studies in adult rats, using an adenoviral-associated vector (rAAV) to deliver the cells into the brains of animals made parkinsonian by the neurotoxin 6-hydroxydopamine (6-OHDA). Her group is also studying similar cell transplantation in an animal model of spinal cord injury.
November 2004 Project Update:
Dr. Malu G. Tansey and her working group at the University of Texas (Dallas) attempted to differentiate into neuron-like cells two separate human cell lines taken from fatty tissue. Though one line, when exposed to the cocktail of chemicals used to "neuritize" the cells regularly resulted in cell death, the other, identified in rats by a group at UCLA, could be reproduced in human cells at Dallas, was isolated and expanded and, when neuritized, modified into what she calls Adipose-Derived Adult Progenitor (ADAP) cells.
These cells proved to be nestin- and tyrosine hydroxylase-positive (indicative of neuronal function), suggesting that they can be tested in animals in attempts to improve motor abilities of rodents that have been made parkinsonian with lesions in their substantias nigras. Presently the group is working to accomplish longer survival of these cells in order to do additional in vivo studies in the animals' midbrain (for PD) and spinal cord (for spinal cord injury).
Grant to: He-Jin Lee, Ph.D.
Project Title: The Effect of Dopamine Levels on Alpha-Synuclein Aggregation
Dr. He-Jin Lee of the Parkinson's Institute (Sunnyvale, California) will use a human cell line in an attempt to determine the interplay between the neurotransmitter dopamine (DA) and the protein alpha-synuclein (@-synuclein). By treating these differentiated cells with individual and combinations of available drugs, she hopes to learn why @-synuclein accumulates in Lewy bodies (found in brain tissue of patients with degenerative disorders, especially PD), as well as provide more insight into the capabilities of @-synuclein as it may be both protective and toxic, depending upon its selectivity in specific neuronal populations. The ultimate goal of Dr. Lee's work, of course, would be to design neuroprotectivbe strategies.
5. The Michael J. Fox Foundation for Parkinson's Research will use its grant toward the Community Fast Track 2003 initiative. Fast Track is an investigator-initiated, peer-reviewed program that considers a broad range of research applications relevant to the cure, cause, prevention or improved treatment of Parkinson's disease. It was designed to support cutting-edge research, while streamlining the grant making process and compressing the timeline in which scientist receive award money. For more information see its website at www.michaeljfox.org.
6. The Parkinson Alliance is proud to be part of The Michael J. Fox Foundation for Parkinson's Research "Community Fast Track 2003." The Alliance will use its grant toward this program.
Under this program, researchers are invited to submit investigator-initiated grant applications to conduct research relevant to the cure, cause, prevention or improved treatment of Parkinson's disease (PD) and its complications. The intent of this RFA is to stimulate novel, innovative, and/or high-impact approaches to the field of Parkinson's disease as well as to fill funding gaps missed by more conventional funding sources. It was designed to support cutting-edge research, while streamlining the grant making process and compressing the timeline in which scientist receive award money. For more information, see its website at www.parkinsonalliance.org.