Schizophrenia is a chronic and debilitating psychiatric illness affecting 1% of the world's population. N-methyl-D-aspartic acid receptor hypofunction has been implicated for the pathophysiology of the illness based on pharmacologic and molecular genetics studies. Recently, we have reported the first evidence that N-methyl-D-aspartic acid receptor receptor function was decreased in postmortem brain tissues of patients with schizophrenia. N-methyl-D-aspartic acid receptor receptor function is governed by highly regulated and intricate protein protein interactions in the receptor protein complexes. The primary goal of the proposed research is to delineate altered protein composition of the N-methyl-D-aspartic acid receptor complex in human postmortem brain tissue from schizophrenic subjects (Aim 1). N-methyl-D- aspartic acid receptor complexes will be immunoprecipitated from post-synaptic density fractions isolated from human schizophrenic and matched control pre-frontal cortexes. Receptor complex composition will be assessed qualitative and quantitatively by targeted mass spectroscopy method. Dysregulations in protein interactions could be due to altered the phosphorylation states of post-synaptic density protein -95 and N- methyl-D-aspartic acid receptor- NR2A. Testing this hypothesis will require phosphotomic analysis of postmortem tissues. As the secondary goal of this project, we will develop and establish the method to quantify target phosphorylations by mass spectroscopy in conjunction with the postmortem brain tissue stimulation paradigm, which will then be applied to a small set of postmortem brain tissues (Aim 2).
While Aim 2 projects will remain as a pilot study, the applicant's experience and training will help define the trajectory of his career in the field of phosphotomic analysis for psychiatric pathology. Successful completion of this project will shed light on the extend of altered protein interactions and phosphorylation at the N- methyl-D-aspartic acid receptor. This data will provide mechanistic information as to the impact of schizophrenia risk genes on disease pathology and inform new platforms for drug discovery. Relevance: Neurotransmitters receive a lot of attention for their role in psychiatric illnesses, such as schizophrenia. The goal of this project is to investigate the machinery in the cell responsible for interpreting these neurotransmitter signals and determine if they are dysfunctional in the brains of schizophrenic patients. This research will aid our understanding of the disease and open new doors for drug discovery.
| MacDonald, Matthew L; Ciccimaro, Eugene; Prakash, Amol et al. (2012) Biochemical fractionation and stable isotope dilution liquid chromatography-mass spectrometry for targeted and microdomain-specific protein quantification in human postmortem brain tissue. Mol Cell Proteomics 11:1670-81 |
