Identification of Novel Brain Biomarkers

Abstract

Background:The diagnosis of diseases leading to brain injury, such as stroke, Alzheimer disease, and Parkinson disease, can often be problematic. In this study, we pursued the discovery of biomarkers that might be specific and sensitive to brain injury. Methods: We performed gene array analyses on a mouse model to look for biomarkers that are both preferentially and abundantly produced in the brain. Via bioinformatics databases, we identified the human homologs of genes that appeared abundant in brain but not in other tissues. We then confirmed protein production of the genes via Western blot of various tissue homogenates and assayed for one of the markers, visinin-like protein 1 (VLP-1), in plasma from patients after ischemic stroke. Results: Twenty-nine genes that were preferentially and abundantly expressed in the mouse brain were identified; of these 29 genes, 26 had human homologs. We focused on 17 of these genes and their protein products on the basis of their molecular characteristics, novelty, and/or availability of antibodies. Western blot showed strong signals in brain homogenates for 13 of these proteins. Tissue specificity was tested by Western blot on a human tissue array, and a sensitive and quantitative sandwich immunoassay was developed for the most abundant gene product observed in our search, VLP-1. VLP-1 was detected in plasma of patients after stroke and in cerebrospinal fluid of a rat model of stroke. Conclusions: The use of relative mRNA production appears to be a valid method of identifying possible biomarkers of tissue injury. The tissue specificity suggested by gene expression was confirmed by Western

Neurobiochemical Markers of Brain Damage in Cerebrospinal Fluid of Acute Ischemic Stroke Patients

“…These findings indicate that tau protein concentrations in CSF probably reflect axonal damage. Visinin-like protein-1 also has recently been identified as a promising biomarker for brain injury (32 ). Fig.…”

Expression of the Na+/K+-transporting ATPase gamma subunit FXYD2 in renal tumors

“…Two rabbits (9472 and 9473) were each immunized with an equal concentration mixture of KLH-P-4840 (G 53 GNKKRRQINEDE 65 ) and KLH-P-4841 (G 8 GGSPKGDVDPFYY 21 ) at Harlan Bioproducts for Sciences (Madison, WI). Individual rabbit antiserum was affinity-purified over a SulfoLink P-4840 column with the non-bound flow-through applied to a SulfoLink P-4841 column.…”

“…Antibody concentration was determined by UV scanning from 240 to 320 nm, using A 280 ¼ 1.4 ml/(mg Á cm) and then stored at 4 1C. The procedure for western blots has been described, 21 and the alkaline phosphatase substrate for western blots 5-bromo,4-chloro,3-indoylphosphate/nitrobluetetrazolium was obtained from Kirkegaard and Perry (Gaithersburg, MD).…”

Biomarker Discovery and Validation

“…Perhaps because of the daunting complexity of plasma profiling, as well as the recent successful application of transcript profiling to the field of cancer biomarkers (6 ), Laterza et al (1 ) opted for the latter, more mature technology for the identification of novel biomarkers of brain injury. Using transcript profiling of isolated organ preparations, Laterza et al identified mRNAs that were highly enriched in the brain.…”