Parkinson Disease: Nass R

Nass R, Merchant KM, Ryan T. · Department of Pharmacology and Toxicology, Center for Environmental Health, and Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. · Mol Interv. · Pubmed #19144901 No free full text.

Abstract: It has been over forty years since dopamine neuron degeneration in the substantia nigra and Lewy body formation within surviving cells were described as the pathological hallmarks of Parkinson's disease (PD). Although research in the intervening decades particularly in the last twenty-five years has yielded a variety of robust animal models and invaluable mechanistic insights into PD-associated neuronal dysfunction and cell death, therapeutic agents have not been forthcoming to alter the course of PD. Recently, the screening of experimental therapeutics for PD has been pursued through the use of genetically tractable models, such as the nematode Caenorhabditis elegans. This simple worm remarkably recapitulates the basic cellular and molecular pathways associated with PD, is amenable to facile genetic methods, and through the use of high-throughput screening technologies, provides powerful new opportunities for the in vivo identification of therapeutic targets. In this review we briefly describe the utility that the C. elegans model system may have for PD drug discovery.

Nass R, Blakely RD. · Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6420, USA. · Annu Rev Pharmacol Toxicol. · Pubmed #12415122 No free full text.

Abstract: The neurotransmitter dopamine (DA) plays a central role in the coordination of movement, attention, and the recognition of reward. Loss of DA from the basal ganglia, as a consequence of degeneration of neurons in the substantia nigra, triggers postural instability and Parkinson's disease (PD). DA transporters (DATs) regulate synaptic DA availability and provide a conduit for the uptake of DA mimetic neurotoxins, which can be used to evoke neuronal death and Parkinson-like syndrome. Recently, we have explored the sensitivity of DA neurons in the nematode Caenorhabditis elegans to the Parkinsonian-inducing neurotoxin 6-hydroxydopamine (6-OHDA) and found striking similarities, including DAT dependence, to neurodegeneration observed in mammalian models. In this review, we present our findings in the context of molecular and behavioral dimensions of DA signaling in C. elegans with an eye toward opportunities for uncovering DAT mutants, DAT regulators, and components of toxin-mediated cell death.

Vartiainen S, Pehkonen P, Lakso M, Nass R, Wong G. · Department of Neurobiology, A.I. Virtanen Institute, Kuopio, 70211, Finland. · Neurobiol Dis. · Pubmed #16626960 No free full text.

Abstract: Alpha-synuclein containing cellular inclusions are a hallmark of Parkinson Disease, Lewy Body Dementia, and Multiple System Atrophy. A genome wide expression screen was performed in C. elegans overexpressing both wild-type and A53T human alpha-synuclein. 433 genes were up- and 67 genes down-regulated by statistical and fold change (> or <2) criteria. Gene ontology (GO) categories within the regulated gene lists indicated over-representation of development and reproduction, mitochondria, catalytic activity, and histone groups. Seven genes (pdr-1, ubc-7, pas-5, pas-7, pbs-4, RPT2, PSMD9) with function in the ubiquitin-proteasome system and 35 mitochondrial function genes were up-regulated. Nine genes that form histones H1, H2B, and H4 were down-regulated. These results demonstrate the effects of alpha-synuclein on proteasome and mitochondrial complex gene expression and provide further support for the role of these complexes in mediating neurotoxicity. The results also indicate an effect on nuclear protein genes that suggests a potential new avenue for investigation.