Proteomic analysis discovers potential biomarkers of early traumatic axonal injury in the brainstem.

OBJECTIVE: Application of Tandem Mass Tags (TMT)-based LC-MS/MS analysis to screen for differentially expressed proteins (DEPs) in traumatic axonal injury (TAI) of the brainstem and to predict potential biomarkers and key molecular mechanisms of brainstem TAI. METHODS: A modified impact acceleration injury model was used to establish a brainstem TAI model in Sprague-Dawley rats, and the model was evaluated in terms of both functional changes (vital sign measurements) andstructural changes (HE staining, silver-plating staining and ß-APP immunohistochemical staining). TMT combined with LC-MS/MS was used to analyse the DEPs in brainstem tissues from TAI and Sham groups. The biological functions of DEPs and potential molecular mechanisms in the hyperacute phase of TAI were analysed by bioinformatics techniques, and candidate biomarkers were validated using western blotting and immunohistochemistry on brainstem tissues from animal models and humans. RESULTS: Based on the successful establishment of the brainstem TAI model in rats, TMT-based proteomics identified 65 DEPs, and bioinformatics analysis indicated that the hyperacute phase of TAI involves multiple stages of biological processes including inflammation, oxidative stress, energy metabolism, neuronal excitotoxicity and apoptosis. Three DEPs, CBR1, EPHX2 and CYP2U1, were selected as candidate biomarkers and all three proteins were found to be significantly expressed in brainstem tissue 30 min-7 days after TAI in both animal models and humans. CONCLUSION: Using TMT combined with LC-MS/MS analysis for proteomic study of early TAI in rat brainstem, we report for the first time that CBR1, EPHX2 and CYP2U1 can be used as biomarkers of early TAI in brainstem by means of western blotting and immunohistochemical staining, compensating for the limitations of silver-plating staining and ß-APP immunohistochemical staining, especially in the case of very short survival time after TAI (shorter than 30 min). A number of other proteins that also have a potential marker role are also presented, providing new insights into the molecular mechanisms, therapeutic targets and forensic identification of early TAI in brainstem.

The Role of Non-coding RNAs in Methamphetamine-Induced Neurotoxicity.

Methamphetamine (METH) is an amphetamine-type stimulant that is highly toxic to the central nervous system (CNS). Repeated intake of METH can lead to addiction, which has become a globalized problem, resulting in multiple public health and safety problems. Recently, the non-coding RNA (ncRNA) has been certified to play an essential role in METH addiction through various mechanisms. Herein, we mainly focused on three kinds of ncRNAs including long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), which are involved in neurotoxicity effects such as cognitive impairment, behavioral abnormalities, and psychiatric disorders due to METH abuse. In addition, differential expression (DE) ncRNAs also suggest that specific responses and sensitivity to METH neurotoxicity exist in different brain regions and cells. We summarized the relationships between the ncRNAs and METH-induced neurotoxicity and psychiatric disturbances, respectively, hoping to provide new perspectives and strategies for the prevention and treatment of METH abuse. Schematic diagram of the non-coding RNAs (ncRNAs) was involved in methamphetamine (METH)-induced neurotoxicity. The ncRNAs were involved in METH-induced blood-brain barrier disruption, neuronal, astrocyte, and microglial damage, and synaptic neurotransmission impairment. The study of ncRNAs is a hot spot in the future to further understand the neurotoxicity of METH and provide more favorable scientific support for clinical diagnosis and innovation of related treatments.