Gene expression patterns following unilateral traumatic brain injury reveals a local pro-inflammatory and remote anti-inflammatory response

Abstract Background: Traumatic brain injury (TBI) is a systemic injury that disrupts a complex arrangement of interacting cells in the brain and in the gastrointestinal tract (GI). Disruption in the brain results in neuroinflammation, in which microglia are a central component along with cytokines and other soluble factors [pro and anti-inflammatory microglia (M1:M2)]. Disruption in the GI due to TBI results in a systemic inflammation which is dependent upon the gut microbiome (GM). Gut microbiome can influence microglia in the brain via the gut-brain axis. In order to determine if the microbiome-microglia connections via the gut-brain axis can be modulated, we used probiotics and antibiotics in a rodent TBI model to evaluate the microbiome-microglial connections in acute and chronic experiments.Methods: The temporal effects of treatment (probiotics or antibiotics) were used to evaluate the gut-associated lymphoid tissue (GALT) influence on the microglial response at 72 hours or 21 days after a cortical contusion injury (CCI), a rodent model of TBI. Injured animals received daily probiotics, antibiotics, or no treatment. Sham-injured animals (controls) did not receive any treatment.Results: Twenty-one days of probiotic treatment attenuated the pro-inflammatory response of microglia (M1:M2) after CCI. The post-injury inflammatory response was heightened in the GALT with antibiotic-induced dysbiosis which resulted in amplification of the pro-inflammatory microglial response. Conclusions: Probiotic treatment after TBI is a potential therapeutic in attenuating microglial activation through anti-inflammatory signaling.

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The Gene Coexpression Analysis Identifies Functional Modules Dynamically Changed After Traumatic Brain Injury

Computational and Mathematical Methods in Medicine ◽

10.1155/2021/5511598 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Zhi-jie Zhao ◽

Dong-po Wei ◽

Rui-zhe Zheng ◽

Tinghua Peng ◽

Xiang Xiao ◽

...

Keyword(s):

Gene Expression ◽

Traumatic Brain Injury ◽

Brain Injury ◽

Cell Activation ◽

Expression Profiles ◽

Expression Patterns ◽

Protein Translation ◽

Functional Modules ◽

Coexpression Analysis ◽

Gene Coexpression

Traumatic brain injury (TBI) is a major cause of morbidity and mortality, both in adult and pediatric populations. However, the dynamic changes of gene expression profiles following TBI have not been fully understood. In this study, we identified the differentially expressed genes (DEGs) following TBI. Remarkably, Serpina3n, Asf1b, Folr1, LOC100366216, Clec12a, Olr1, Timp1, Hspb1, Lcn2, and Spp1 were identified as the top 10 with the highest statistical significance. The weighted gene coexpression analysis (WGCNA) identified 12 functional modules from the DEGs, which showed specific expression patterns over time and were characterized by enrichment analysis. Specifically, the black and turquoise modules were mainly involved in energy metabolism and protein translation. The green yellow and yellow modules including Hmox1, Mif, Anxa2, Timp1, Gfap, Cd9, Gja1, Pdpn, and Gpx1 were related to response to wounding, indicating that expression of these genes such as Hmox1, Anxa2, and Timp1 could protect the brains from brain injury. The green yellow module highlighted genes involved in microglial cell activation such as Tyrobp, Cx3cr1, Grn, Trem2, C1qa, and Aif1, suggesting that these genes were responsible for the inflammatory response caused by TBI. The upregulation of these genes has been validated in an independent dataset. These results indicated that the key genes in microglia cell activation may serve as a promising therapeutic target for TBI. In summary, the present study provided a full view of the dynamic gene expression changes following TBI.

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Systems spatiotemporal dynamics of traumatic brain injury at single cell resolution reveals humanin as a therapeutic target

10.21203/rs.3.rs-765030/v1 ◽

2021 ◽

Author(s):

Douglas Arneson ◽

Guanglin Zhang ◽

In Sook Ahn ◽

Zhe Ying ◽

Graciel Diamante ◽

...

Keyword(s):

Gene Expression ◽

Traumatic Brain Injury ◽

Brain Injury ◽

Frontal Cortex ◽

Single Cell ◽

Target Genes ◽

Expression Patterns ◽

Brain Regions ◽

Cellular Heterogeneity ◽

Blood Leukocytes

Abstract The etiology of mild traumatic brain injury (mTBI) remains elusive due to the tissue and cellular heterogeneity of the affected brain regions that underlie cognitive impairments and subsequent neurological disorders. This complexity is further exacerbated by disrupted circuits within and between cell populations across brain regions and the periphery, which occur at different timescales and in spatial domains. We profiled three tissues (hippocampus, frontal cortex, and blood leukocytes) at the acute (24hr) and chronic (7days) phases of mTBI at single cell resolution and demonstrated that the coordinated gene expression patterns across cell types were disrupted and re-organized by TBI at different timescales with distinct regional and cellular patterns. Gene expression-based network modeling identified astrocytes as a key regulator of the cell-cell coordination following mTBI in both hippocampus and frontal cortex across timepoints, and mt-Rnr2, which encodes the mitochondrial peptide humanin, as a potential target for intervention based on its broad regional and dynamic dysregulation following mTBI. Treatment of a murine mTBI model with humanin reversed cognitive impairment caused by mTBI through the restoration of metabolic pathways within astrocytes. Our results offer a systems-level understanding of the dynamic and spatial regulation of gene programs by mTBI and pinpoint key target genes, pathways, and cell circuits that are amenable to therapeutics.

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Ethanol Intoxication Alleviates the Inflammatory Response of Remote Organs to Experimental Traumatic Brain Injury

International Journal of Molecular Sciences ◽

10.3390/ijms21218181 ◽

2020 ◽

Vol 21 (21) ◽

pp. 8181

Author(s):

Baolin Xu ◽

Akila Chandrasekar ◽

Florian olde Heuvel ◽

Maciej Powerski ◽

Aleksander Nowak ◽

...

Keyword(s):

Gene Expression ◽

Traumatic Brain Injury ◽

Brain Injury ◽

Inflammatory Response ◽

Protein Expression ◽

Inflammatory Mediators ◽

Ethanol Intoxication ◽

Gene Expressions ◽

Hmgb1 Expression ◽

Tissue Homogenates

Traumatic brain injury (TBI) may cause damage to distant organs. Acute ethanol intoxication (EI) induces complex local and systemic anti-inflammatory effects and influences the early outcomes of traumatized patients. Here, we evaluated its effects on the BI-induced expression of local inflammatory mediators in the trauma-remote organs the lungs and liver. Male mice were exposed to ethanol as a single oral dose (5g·kg–1, 32%) before inducing a moderate blunt TBI. Sham groups underwent the same procedures without TBI. Ether 3 or 6h after the TBI, the lung and liver were collected. The gene expression of HMGB1, IL-6, MMP9, IL-1β, and TNF as well as the homogenate protein levels of receptor for advanced glycation end products (RAGE), IL-6, IL-1β, and IL-10 were analyzed. Liver samples were immunohistologically stained for HMGB1. EI decreased the gene expressions of the proinflammatory markers HMGB1, IL-6, and MMP9 in the liver upon TBI. In line with the reduced gene expression, the TBI-induced protein expression of IL-6 in liver tissue homogenates was significantly reduced by EI at 3h after TBI. While the histological HMGB1 expression was enhanced by TBI, the RAGE protein expression in the liver tissue homogenates was diminished after TBI. EI reduced the histological HMGB1 expression and enhanced the hepatic RAGE protein expression at 6h post TBI. With regard to the lungs, EI significantly reduced the gene expressions of HMGB1, IL-6, IL-1β, and TNF upon TBI, without significantly affecting the protein expression levels of inflammatory markers (RAGE, IL-6, IL-1β, and IL-10). At the early stage of TBI-induced inflammation, the gene expression of inflammatory mediators in both the lungs and liver is susceptible to ethanol-induced remote effects. Taken together, EI may alleviate the TBI-induced pro-inflammatory response in the trauma-distant organs, the lungs and liver, via the HMGB1-RAGE axis.

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