Recent Advances in Fluorescence Imaging of Traumatic Brain Injury in Animal Models

Integrative analysis of TBI data reveals Lgmn as a key player in immune cell-mediated ferroptosis

BACKGROUND

Traumatic brain injury (TBI) is a central nervous system disease caused by external trauma, which has complex pathological and physiological mechanisms. The aim of this study was to explore the correlation between immune cell infiltration and ferroptosis post-TBI.

METHODS

This study utilized the GEO database to download TBI data and performed differentially expressed genes (DEGs) and ferroptosis-related differentially expressed genes (FRDEGs) analysis. DEGs were further analyzed for enrichment using the DAVID 6.8. Immunoinfiltration cell analysis was performed using the ssGSEA package and the Timer2.0 tool. The WGCNA analysis was then used to explore the gene modules in the data set associated with differential expression of immune cell infiltration and to identify the hub genes. The tidyverse package and corrplot package were used to calculate the correlations between hub genes and immune cell infiltration and ferroptosis-marker genes. The miRDB and TargetScan databases were used to predict complementary miRNAs for the Hub genes selected from the WGCNA analysis, and the DIANA-LncBasev3 tool was used to identify target lncRNAs for the miRNAs, constructing an mRNA-miRNA-lncRNA regulatory network.

RESULTS

A total of 320 DEGs and 21 FRDEGs were identified in GSE128543. GO and KEGG analyses showed that the DEGs after TBI were primarily associated with inflammation and immune response. Xcell and ssGSEA immune infiltration cell analysis showed significant infiltration of T cell CD4+ central memory, T cell CD4+ Th2, B cell memory, B cell naive, monocyte, macrophage, and myeloid dendritic cell activated. The WGCNA analysis identified two modules associated with differentially expressed immune cells and identified Lgmn as a hub gene associated with immune infiltrating cells. Lgmn showed significant correlation with immune cells and ferroptosis-marker genes, including Gpx4, Hspb1, Nfe2l2, Ptgs2, Fth1, and Tfrc. Finally, an mRNA-miRNA-lncRNA regulatory network was constructed using Lgmn.

CONCLUSION

Our results indicate that there is a certain correlation between ferroptosis and immune infiltrating cells in brain tissue after TBI, and that Lgmn plays an important role in this process.

Potential Biomarkers in Experimental Animal Models for Traumatic Brain Injury

Traumatic brain injury (TBI) is a complex and multifaceted disorder that has become a significant public health concern worldwide due to its contribution to mortality and morbidity. This condition encompasses a spectrum of injuries, including axonal damage, contusions, edema, and hemorrhage. Unfortunately, specific effective therapeutic interventions to improve patient outcomes following TBI are currently lacking. Various experimental animal models have been developed to mimic TBI and evaluate potential therapeutic agents to address this issue. These models are designed to recapitulate different biomarkers and mechanisms involved in TBI. However, due to the heterogeneous nature of clinical TBI, no single experimental animal model can effectively mimic all aspects of human TBI. Accurate emulation of clinical TBI mechanisms is also tricky due to ethical considerations. Therefore, the continued study of TBI mechanisms and biomarkers, of the duration and severity of brain injury, treatment strategies, and animal model optimization is necessary. This review focuses on the pathophysiology of TBI, available experimental TBI animal models, and the range of biomarkers and detection methods for TBI. Overall, this review highlights the need for further research to improve patient outcomes and reduce the global burden of TBI.

Novel lysosome-targeted fluorescent molecular rotors based on a cyanine-like modular system and their application in living cells

Two novel fluorescence molecular rotors DpIn and NaIn were designed and synthesized involving of indolium units linked with meta-diphenol or ortha-naphthalenediol moiety, respectively. They underwent intramolecular charge transfer to form a cyanine-like modular system at a physiological pH. In glycerol aqueous solutions, the probe DpIn exhibited NIR strong emission (3-fold) at ca. 700 nm, while the probe NaIn displayed a turn-on emission (8-fold) with a larger Stokes shift (⊿λ ≈ 97 nm). The HeLa cell imaging experiments indicated probe DpIn and NaIn both exhibited excellent selectivity for staining intracellular lysosomes instead of mitochondria. ¹H NMR spectra revealed that more electrons were accumulated around benzene ring of indolium groups, which could be the evidence for its basic character leading to the lysosomes targeted staining. Furthermore, the probe NaIn proved to be an ideal lysosome-targeting tracer for monitor the changes of viscosity caused by stimuli in living cells.