Top-down proteomics with mass spectrometry imaging: a pilot study towards discovery of biomarkers for neurodevelopmental disorders.
In the developing mammalian brain, inhibition of NMDA receptor can induce widespread neuroapoptosis, inhibit neurogenesis and cause impairment of learning and memory. Although some mechanistic insights into adverse neurological actions of these NMDA receptor antagonists exist, our understanding of the full spectrum of developmental events affected by early exposure to these chemical agents in the brain is still limited. Here we attempt to gain insights into the impact of pharmacologically induced excitatory/inhibitory imbalance in infancy on the brain proteome using mass spectrometric imaging (MSI). Our goal was to study changes in protein expression in postnatal day 10 (P10) rat brains following neonatal exposure to the NMDA receptor antagonist dizocilpine (MK801). Analysis of rat brains exposed to vehicle or MK801 and comparison of their MALDI MS images revealed differential relative abundances of several proteins. We then identified these markers such as ubiquitin, purkinje cell protein 4 (PEP-19), cytochrome c oxidase subunits and calmodulin, by a combination of reversed-phase (RP) HPLC fractionation and top-down tandem MS platform. More in-depth large scale study along with validation experiments will be carried out in the future. Overall, our findings indicate that a brief neonatal exposure to a compound that alters excitatory/inhibitory balance in the brain has a long term effect on protein expression patterns during subsequent development, highlighting the utility of MALDI-MSI as a discovery tool for potential biomarkers.
State Key Laboratory of Natural Medicines, Key Lab of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, PR China; Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing, PR China; School of Pharmacy, University of Wisconsin Madison, Madison, Wisconsin, United States of America.
Hui
H
Ye
Department of Neurology, University of Wisconsin Madison, Madison, Wisconsin, United States of America.
Rakesh
R
Mandal
Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, United States of America.
Adam
A
Catherman
Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, United States of America.
Paul M
PM
Thomas
Proteomics Center of Excellence, Northwestern University, Evanston, Illinois, United States of America.
Neil L
NL
Kelleher
Department of Neurology, University of Wisconsin Madison, Madison, Wisconsin, United States of America.
Chrysanthy
C
Ikonomidou
School of Pharmacy, University of Wisconsin Madison, Madison, Wisconsin, United States of America; Department of Chemistry, University of Wisconsin Madison, Madison, Wisconsin, United States of America.
Lingjun
L
Li
D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D001923:Brain Chemistry / Q000187:drug effects; D001927:Brain Diseases / Q000378:metabolism* / Q000473:pathology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D013058:Mass Spectrometry; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D040901:Proteomics; D051381:Rats; D017208:Rats, Wistar
D015415:Biomarkers; D018691:Excitatory Amino Acid Antagonists; D009419:Nerve Tissue Proteins; D016291:Dizocilpine Maleate