DECONVOLUTION OF WHOLE BLOOD TRANSCRIPTOMES FOR DECISIONABLE BIOMARKER IDENTIFICATION IN TBI

Approximately 1.7 million Americans sustain a traumatic brain injury (TBI) per year. Severe and moderate TBI are caused by heterogeneous types of injuries and results in a wide range of short- or long-term effects on cognitive function, emotion, motor function and/or emotion. Approximately 75% of these injuries are considered mild (mTBI), where only a brief loss of consciousness and change in cognitive function is initially observed. Despite the appearance of health, individuals that have recovered from mTBI may be susceptible to worse outcome after a subsequent second injury and may even result in sudden coma or death. More often, repeated mild TBI events even over extended durations are associated with cumulative decline in memory function, inability to concentrate, recurrent headaches, and dizziness. Recently, it has been determined that the adaptive immune system can respond and develop memory to CNS injury and activate production of autoantibodies with pathogenic potential. Leukocytes associated with responses to human injury or illness generates specific and identifiable gene expression signatures. However, the precise response and leukocyte gene expression signatures after TBI events have not been investigated. Our goal in this project is to profile complete transcriptomes of whole blood from TBI individuals to identify candidate biomarkers that molecularly classify TBI by clinical relevance.We have recently profiled the profiled complete transcriptomes from whole blood of mTBI injured rodent subjects and observed that lymphocyte-associated gene expression signatures significantly stratify individual samples by impact magnitude, type of injury model, and time post-injury. Furthermore, additional gene expression signatures were identified by accounting for changes in lymphocyte population number in blood from rodent TBI subjects. Our hypothesis is that lymphocyte-associated transcripts in whole blood are candidates for biomarker and molecular diagnostics in clinical samples from human TBI patients.We propose to perform transcriptome analysis of PaxGene Blood RNA samples from the CNRM Biorepository to determine whether blood-based transcript candidate biomarkers have potential utility for human TBI. As part of this workflow, we would process and isolate high integrity total RNA from the PaxGene blood samples and redeposit isolated RNA material back to the CNRM Biorepository for material to be used in other studies. Additional, we aim to deposit cDNA generated from RNA samples to the CNRM Biorepository as a component of our sequencing workflow. If successful with this proposed project, we anticipate using the results in support of our findings in animal mTBI studies and as data to support a project for biomarker validation in future human TBI cohorts.We are confident that we can extend the utilization of PaxGene Blood RNA samples of TBI patients with our approach of processing, redeposition and data sharing from the complete transcriptomic profiling workflow. We hope that success with this exploratory project will provide a framework for additional translationally relevant biomarker discovery studies. By completing this proposed project, we will prove a greater understanding of the immune system related response to mTBI injuries and identify novel biomarker targets with a long-term goal of providing new strategies for improving outcomes for injured individuals and facilitating service member return to duty.