ATAC-seq of mouse cortex undergoing early degradation after traumatic brain injury (TBI)
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ABSTRACT: Advances in molecular diagnostics have enabled accurate disease diagnosis. However, the application of molecular biology technology in the field of forensic medicine, especially in forensic pathology, is still limited. Degraded samples with altered physicochemical properties pose challenges for molecular techniques. Identifying degradation-resistant, sensitive techniques is key for forensic molecular pathology. ATAC-seq maps open chromatin and is increasingly used in disease diagnosis and mechanism studies. Given forensic use of degraded DNA, we explored ATAC-seq's potential for analyzing degraded forensic samples. In a TBI model, ATAC-seq detected injury-induced chromatin changes after 2h degradation. We identified 1,432 TBI-associated loci with robust chromatin changes unaffected by degradation. These loci have potential as a panel of biomarkers for molecular diagnosis from degraded forensic samples.
Project description:The aim of this experiment was to determine the amount of RNA-seq signal degradation that results from MARIS and to test how well 4 different RNA-seq library construction techniques perform on partially degraded RNA.
Project description:Diagnosis of fatal hypothermia is considered to be difficult in forensic practice. In this study, in order to identify novel molecular markers of fatal hypothermia, we made rat models of mild, moderate and severe hypothermia, and performed body temperature-dependent gene expression analysis in illiopsoas muscle using next-generation sequencing.
Project description:Remote ischemic conditioning (RIC) treatment has been shown to modify levels of traumatic brain injury (TBI) pathology related proteins, however, the mechanism is not widely understood. This study utilized LC-MS/MS to identify protein biomarkers of RIC treatment after TBI in mouse models.
Project description:Introduction: Post-traumatic coagulopathy (PTC) is a critical pathology in traumatic brain injury (TBI), however, its potential mechanism is not clear. To explore this in peripheral samples, we integrated single cell RNA-sequencing and T cell repertoire (TCR)-sequencing across a cohort of patients with TBI. Methods: Clinical samples from patients with more brain severity demonstrated altered mRNAs.
Project description:Background: Traumatic brain injury (TBI) often results in diverse molecular responses, challenging traditional proteomic studies that measure average changes at tissue levels and fail to capture the complexity and heterogeneity of the affected tissues. Spatial proteomics offers a solution by providing insights into sub-region-specific alterations within tissues. This study focuses on the hippocampal sub-regions, analyzing proteomic expression profiles in mice at the acute (1 day) and subacute (7 days) phases of post-TBI to understand subregion-specific vulnerabilities and long-term consequences. Methods: Three mice brains were collected from each group including Sham, 1-day post-TBI and 7-day post-TBI. Hippocampal subregions were extracted using Laser Microdissection (LMD); and subsequently analyzed by label-free quantitative proteomics. Results: The spatial analysis reveals region-specific protein abundance changes, highlighting the elevation of FN1, LGALS3BP, HP, and MUG-1 in the stratum moleculare (SM), suggesting potential immune cell enrichment post-TBI. Notably, established markers of chronic traumatic encephalopathy, IGHM and B2M, exhibit specific upregulation in the dentate gyrus bottom (DG2) independent of direct mechanical injury. Metabolic pathway analysis identifies disturbances in glucose and lipid metabolism, coupled with activated cholesterol synthesis pathways enriched in SM at 7-Day post-TBI and subsequently in deeper DG1 and DG2 suggesting a role in neurogenesis and onset of recovery. Coordinated activation of neuroglia and microtubule dynamics in DG2 suggest recovery mechanisms in less affected regions. Cluster analysis revealed spatial variations post-TBI, indicative of dysregulated neuronal plasticity and neurogenesis and further predisposition to neurological disorders. TBI-induced protein upregulation (MUG-1, PZP, GFAP, TJP, STAT-1 and CD44) across hippocampal sub-regions indicates shared molecular responses and links to neurological disorders. Spatial variations were demonstrated by proteins dysregulated in both or either of the time-points exclusively in each subregion (ELAVL2, CLIC1 in PL, CD44 and MUG-1 in SM, and SHOC2, LGALS3 in DG). Conclusions: Utilizing advanced spatial proteomics techniques, the study unveils the dynamic molecular responses in distinct hippocampal subregions post-TBI. It uncovers region-specific vulnerabilities and dysregulated neuronal processes, and potential recovery-related pathways that contribute to our understanding of TBI’s neurological consequences and provides valuable insights for biomarker discovery and therapeutic targets.
Project description:Understanding the impact of DNA methylation within different disease contexts often requires accurate assessment of these modifications in a genome-wide fashion. Frequently, patient-derived tissue stored in long-term hospital tissue banks have been preserved using formalin-fixation paraffin-embedding (FFPE). While these samples can comprise valuable resources for studying disease, the fixation process ultimately compromises the DNA’s integrity and leads to degradation. Degraded DNA can complicate CpG methylome profiling using traditional techniques, particularly when performing methylation sensitive restriction enzyme sequencing (MRE-seq), yielding high backgrounds and resulting in lowered library complexity. Here, we provide results using our new MRE-seq protocol (Capture MRE-seq), tailored to preserving unmethylated CpG information when using samples with highly degraded DNA. The results using Capture MRE-seq correlate well (0.92) with traditional MRE-seq calls when profiling non-degraded samples, and can recover unmethylated regions in highly degraded samples when traditional MRE-seq fails, which we validate using bisulfite sequencing-based data (WGBS) as well as methylated DNA immunoprecipitation followed by sequencing (MeDIP-seq).
Project description:Purpose: RNA analysis of post-mortem tissues, or thanathotranscriptomics, has become a topic of interest in forensic science due to the essential information it can provide in forensic case investigations. Several studies have previously investigated the effect of death on gene transcription, but it has never been conducted with samples of the same individual. Methods: For the first time, a longitudinal mRNA expression analysis study was performed with post-mortem human blood samples from individuals with a known time of death. Results: The results reveal that, after death, two clearly differentiated groups of up- and down-regulated genes can be detected. Pathway analysis suggests active processes, rather than passive degradation, are the source of early post-mortem changes of gene expression in blood. In addition, a generalised linear model with an elastic net restriction predicted post-mortem interval with an RMSE of 4.88 hours. Conclusions: Although promising, the forensic relevance of the model is currently limited and should be further improved in more extended studies.