Project 4: A Developmental Perspective to Nitrosative/Oxidative Susceptibility

Information

  • Research Project
  • 8292290
  • ApplicationId
    8292290
  • Core Project Number
    P01ES016738
  • Full Project Number
    5P01ES016738-04
  • Serial Number
    16738
  • FOA Number
  • Sub Project Id
    4
  • Project Start Date
    7/1/2011 - 12 years ago
  • Project End Date
    6/30/2013 - 10 years ago
  • Program Officer Name
  • Budget Start Date
    7/1/2011 - 12 years ago
  • Budget End Date
    6/30/2012 - 11 years ago
  • Fiscal Year
    2011
  • Support Year
    4
  • Suffix
  • Award Notice Date
    9/29/2011 - 12 years ago

Project 4: A Developmental Perspective to Nitrosative/Oxidative Susceptibility

Current insights into the onset of dopaminergic (DA) neuronal dysfunction and/or death (hence, the etiology of Parkinson's Disease [PD]) implicate abnormalities in the unbiquitin-proteasome system (UPS) in response to oxidative and nitrosative stress, leading to protein misfolding. Protein misfolding appears to be mediated, at least in part, by S-nitrosylation of parkin or protein-disulfide isomerase (PDI). Hence, these molecules may provide mechanism-based biomarkers for impending neuronal demise or, conversely, if levels go down, their recovery. Dysfunctional mitochondria can lead to the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). In particular, there is growing evidence that mitochondrial complex 1 dysfunction results in an increase in ROS, eventually leading to the aggregation of a-synuclein. Oligomers/protofibrils of a-synuclein appear to play a central role in neurodegeneration - and, particularly, PD pathology -- likely through proteasome inhibition. Dysfunction of the UPS is likely the basis for familial PD characterized by mutations in Parkin, PINK1 and DJ-1. Recently, the Lipton group (Project 3) has demonstrated that S-nitrosylation of parkin or PDI, a key stress-induced chaperone in the endoplasmic reticulum (ER), has been linked to protein misfolding and neurodegeneration in PD models and in brains of PD patients. In addition, in preliminary studies, we have observed that mice carrying mutant a-synuclein (asyn) show dramatically increased S-nitrosylation of PDI;i.e., increased nitrosative/oxidative stress appears to be present in the context of such a mutation. There appears to be a developmental component to PD onset. For example, although, mutant a-syn is present in the earliest CNS progenitors of patients with some familial forms of PD, the disease does not typically manifest itself until adulthood. Progressive DA dysfunction also appears to be a component of the aging process. Immature neural progenitor cells appear to be resistant to oxidative stress in a manner not observed when those same cells become mature. Although human stem cells are typically studied for their therapeutic potential, they also provide (perhaps even more compellingly) models of human cellular development and offer the prospect for modeling human disease (from which novel therapies may, in turn, be derived). We have established defined culture conditions for modeling the iterative steps of DA neuronal development from an undifferentiated human embryonic stem cell (hESC) to a differentiated DA neuron in vitro. Cells at each developmental stage can be engineered to express mutant a-syn and/or "lesioned" pharmacologically with mitochondrial complex inhibitors. In DA neurons, such manipulations produce features emulating PD. Therefore, we propose to use a human stem cell-based system to model the developmental susceptibility of neural precursors to oxidative/nitrosative stress relevant to PD in order to understand mechanisms by which endangered or dysfunctional DA neurons may ultimately be protected. A study of developmental susceptibility may help to develop drugs that will prevent oxidative/nitrosative stress in both endogenous and transplanted neural progenitors. Preserving mesostriatal circuitry is more tractable and safer than attempting to reconstruct proper new connections. However, if, in the future, transplantation into PD patients is required, protecting these exogenous stem cells will also be crucial. It is possible that different protective drugs will be necessary depending on the developmental stage of the neural progenitors used.

IC Name
NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
  • Activity
    P01
  • Administering IC
    ES
  • Application Type
    5
  • Direct Cost Amount
  • Indirect Cost Amount
  • Total Cost
  • Sub Project Total Cost
    279367
  • ARRA Funded
    False
  • CFDA Code
  • Ed Inst. Type
  • Funding ICs
    NIEHS:279367\
  • Funding Mechanism
    Research Projects
  • Study Section
    ZES1
  • Study Section Name
    Special Emphasis Panel
  • Organization Name
    SANFORD-BURNHAM MEDICAL RESEARCH INSTIT
  • Organization Department
  • Organization DUNS
    020520466
  • Organization City
    LA JOLLA
  • Organization State
    CA
  • Organization Country
    UNITED STATES
  • Organization Zip Code
    920371005
  • Organization District
    UNITED STATES