Glial immune-related pathways mediate effects of closed head traumatic brain injury on behavior and lethality in Drosophila
Fig 4
TBI causes changes in gene expression.
(A) Expression levels for whole head inputs are compared to glia-specific TRAP IP and show that glia-specific genes are enriched, including alrm (astrocyte-specific), gli (expressed in subperineurial glia), and repo (pan-glial). Expression of neuron-specific genes elav and nsyb were not significantly altered. Data are normalized for whole head inputs (3 replicates for both whole head inputs and TRAP IP, ** p < 0.01, * p < 0.05, t test). Error bars show SEM. (B) TBI induction results in a large number of differentially expressed genes in glia cells. Around 356 genes are up-regulated, and 156 are down-regulated 1 day after TBI induction. Three days after TBI, gene expression is almost back to baseline, with only 17 genes that are up-regulated and 5 genes that are down-regulated. Seven days after TBI differential gene expression, 24 genes are up-regulated and 22 are down-regulated. (C) Venn diagram showing the overlap of differentially expressed genes (up-regulated + down-regulated) on 1, 3, and 7 days after TBI induction. (D) Scatter plot for glial genes where average reads in the control condition are plotted against average reads 24 hours after TBI (blue dots, log₂fold change ≥ 0.6, Benjamini-adjusted p < 0.1) or down-regulated (red dots, log₂fold change ≤ −0.6, Benjamini-adjusted p < 0.1) 24 hours after TBI induction. AMPs are indicated with green asterisks. Genes with average reads <10 in both control and TBI condition were excluded. All figure-related data are located in S4 Data. alrm, astrocytic leucine-rich repeat molecule; AMP, antimicrobial peptide; elav, embryonic lethal abnormal visual system; gli, gliotactin; nsyb, synaptobrevin; repo, reversed polarity; TBI, traumatic brain injury; TRAP IP, TRAP immunoprecipitated.