A Moderate Blast Exposure Results in Dysregulated Gene Network Activity Related to Cell Death, Survival, Structure, and Metabolism

Abstract

Blast exposure is common in military personnel during training and combat operations, yet biological mechanisms related to cell survival and function that coordinate recovery remain poorly understood. This study explored how moderate blast exposure influences gene expression; specifically, gene-network changes following moderate blast exposure. On day 1 (baseline) of a 10-day military training program, blood samples were drawn, and health and demographic information collected. Helmets equipped with bilateral sensors worn throughout training measured overpressure in pounds per square inch (psi). On day 7, some participants experienced moderate blast exposure (peak pressure ≥5 psi). On day 10, 3 days post-exposure, blood was collected and compared to baseline with RNA-sequencing to establish gene expression changes. Based on dysregulation data from RNA-sequencing, followed by top gene networks identified with Ingenuity Pathway Analysis, a subset of genes was validated (NanoString). Five gene networks were dysregulated; specifically, two highly significant networks: (1) Cell Death and Survival (score: 42), including 70 genes, with 50 downregulated and (2) Cell Structure, Function, and Metabolism (score: 41), including 69 genes, with 41 downregulated. Genes related to ubiquitination, including neuronal development and repair: UPF1, RNA Helicase and ATPase (UPF1) was upregulated while UPF3 Regulator of Nonsense Transcripts Homolog B (UPF3B) was downregulated. Genes related to inflammation were upregulated, including AKT serine/threonine kinase 1 (AKT1), a gene coordinating cellular recovery following TBIs. Moderate blast exposure induced significant gene expression changes including gene networks involved in (1) cell death and survival and (2) cellular development and function. The present findings may have implications for understanding blast exposure pathology and subsequent recovery efforts.

Keywords: NanoString; RNA-sequencing; blast; gene expression; overpressure.

Figure 1

Network shows dysregulated cell death and survival pathway following moderate blast. Genes described in the text included: UPF1, UPF3B, ARRB1, ZBTB7B, flt3, HIBCH, RPL6, RPL35, MRPL1, MRPL3, MRPL36, and MRPL50. Red indicates increased measurement; green represents decreased measurement; with increased color saturation representing more extreme measurement in dataset. Solid lines represent direct interactions, non-targeting interactions, or correlations between chemicals, proteins, or RNA. Dotted lines represent indirect interactions. Purple lines denote the commonly found relationship among the two merged networks. Arrowed lines represent activation, causation, expression, localization, membership, modification, molecular cleavage, phosphorylation, protein-DNA interactions, protein-RNA interactions, regulation of binding, transcription. Shapes represent molecule type (double circle, complex/group; square, cytokine; diamond, enzyme; inverted triangle, kinase; circle, other; triangle, phosphatase; oval, transcription regulator; trapezoid, transporter). The network was generated through the use of IPA (QIAGEN Inc., https://www.qiagenbioinformatics.com/products/ingenuity-pathway-analysis).

Figure 2

Network shows dysregulated structure, function, and development pathway following moderate blast. Genes described in the text include: TRIP12, NAE1, AKT1, MBIP, COA5, and EPB41L3. Red indicates increased measurement; green represents decreased measurement; with increased color saturation representing more extreme measurement in dataset. Solid lines represent direct interactions, non-targeting interactions, or correlations between chemicals, proteins, or RNA. Dotted lines represent indirect interactions. Purple lines denote the commonly found relationship among the two merged networks. Arrowed lines represent activation, causation, expression, localization, membership, modification, molecular cleavage, phosphorylation, protein-DNA interactions, protein-RNA interactions, regulation of binding, transcription. Shapes represent molecule type (double circle, complex/group; square, cytokine; diamond, enzyme; inverted triangle, kinase; circle, other; triangle, phosphatase; oval, transcription regulator; trapezoid, transporter). The network was generated through the use of IPA (QIAGEN Inc., https://www.qiagenbioinformatics.com/products/ingenuity-pathway-analysis).