The m6A methyltransferase METTL3 drives neuroinflammation and neurotoxicity through stabilizing BATF mRNA in microglia.

Persistent neuroinflammation and progressive neuronal loss are defining features of acute brain injury including traumatic brain injury (TBI) and cerebral stroke. Microglia, the most abundant type of brain-resident immune cells, continuously surveil the environment and play a central role in shaping the inflammatory state of the central nervous system (CNS). In the study, we discovered that the protein expression of METTL3 (a m6A methyltransferase) was upregulated in inflammatory microglia independent of increased Mettl3 gene transcription following TBI in both human and mouse subjects. Subsequently, we identified TRIP12, a HECT-domain E3 ubiquitin ligase, as a negative regulator of METTL3 protein expression by facilitating METTL3 K48-linked polyubiquitination. Importantly, selective ablation of Mettl3 inhibited microglial pathogenic activities, diminished neutrophil infiltration, rescued neuronal loss and facilitated functional recovery post-TBI. Using MeRIP-seq and CUT&Tag sequencing, we identified that METTL3 promoted the expression of Basic Leucine Zipper Transcriptional Factor ATF-Like (BATF), which in turn directly bound to a cohort of characteristic inflammatory cytokines and chemokine genes. Enhanced activities of BATF in microglia elicited TNF-dependent neurotoxicity and can also promote neutrophil recruitment through releasing CXCL2. Pharmacological inhibition of METTL3 using a BBB-penetrating drug-loaded nano-system showed satisfactory therapeutic effects in both TBI and stroke mouse models. Collectively, our findings identified METTL3-m6A-BATF axis as a potential therapeutic target for terminating detrimental neuroinflammation and progressive neuronal loss following acute brain injury. METTL3 protein is significantly up-regulated in inflammatory microglia due to the decreased proteasomal degradation mediated by TRIP12 and ERK-USP5 pathways. METTL3 stabilized BATF mRNA stability and promoted BATF expression through the m6A-IGF2BP2-dependent mechanism. Elevated expression of BATF elicits a pro-inflammatory gene program in microglia, and aggravates neuroinflammatory response including local immune responses and peripheral immune cell infiltration. Genetic deletion or pharmaceutically targeting METTL3-BATF axis suppressed microglial pro-inflammatory activities and promoted neurological recovery following TBI and stroke.

Cross-Species Insights into Autosomal Dominant Polycystic Kidney Disease: Provide an Alternative View on Research Advancement.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a prevalent hereditary disorder that affects the kidneys, characterized by the development of an excessive number of fluid-filled cysts of varying sizes in both kidneys. Along with the progression of ADPKD, these enlarged cysts displace normal kidney tissue, often accompanied by interstitial fibrosis and inflammation, and significantly impair renal function, leading to end-stage renal disease. Currently, the precise mechanisms underlying ADPKD remain elusive, and a definitive cure has yet to be discovered. This review delineates the epidemiology, pathological features, and clinical diagnostics of ADPKD or ADPKD-like disease across human populations, as well as companion animals and other domesticated species. A light has been shed on pivotal genes and biological pathways essential for preventing and managing ADPKD, which underscores the importance of cross-species research in addressing this complex condition. Treatment options are currently limited to Tolvaptan, dialysis, or surgical excision of large cysts. However, comparative studies of ADPKD across different species hold promise for unveiling novel insights and therapeutic strategies to combat this disease.

Astrocyte-Derived Extracellular Vesicular miR-143-3p Dampens Autophagic Degradation of Endothelial Adhesion Molecules and Promotes Neutrophil Transendothelial Migration after Acute Brain Injury.

Pivotal roles of extracellular vesicles (EVs) in the pathogenesis of central nervous system (CNS) disorders including acute brain injury are increasingly acknowledged. Through the analysis of EVs packaged miRNAs in plasma samples from patients with intracerebral hemorrhage (ICH), it is discovered that the level of EVs packaged miR-143-3p (EVs-miR-143-3p) correlates closely with perihematomal edema and neurological outcomes. Further study reveals that, upon ICH, EVs-miR-143-3p is robustly secreted by astrocytes and can shuttle into brain microvascular endothelial cells (BMECs). Heightened levels of miR-143-3p in BMECs induce the up-regulated expression of cell adhesion molecules (CAMs) that bind to circulating neutrophils and facilitate their transendothelial cell migration (TEM) into brain. Mechanism-wise, miR-143-3p directly targets ATP6V1A, resulting in impaired lysosomal hydrolysis ability and reduced autophagic degradation of CAMs. Importantly, a VCAM-1-targeting EVs system to selectively deliver miR-143-3p inhibitor to pathological BMECs is created, which shows satisfactory therapeutic effects in both ICH and traumatic brain injury (TBI) mouse models. In conclusion, the study highlights the causal role of EVs-miR-143-3p in BMECs' dysfunction in acute brain injury and demonstrates a proof of concept that engineered EVs can be devised as a potentially applicable nucleotide drug delivery system for the treatment of CNS disorders.

Uncovering the relationship between floating marine litter and human activities in watersheds.

Rivers serve as the primary pathway for transporting floating marine litter (FML) from land to sea. However, the complex dynamics of transboundary rivers pose a significant obstacle when examining the impact of watershed-based human activities on FML distribution. This study conducts year-long monthly monitoring of FML using trawl and visual surveys in the coastal water of a peninsula dominated by indigenous rivers in south China. Overall, small pieces debris dominates FML in the nearshore waters of the peninsula, with meso-sized (0.5 cm-2.5 cm) FML accounting for 73.93 % of the total. The density of FML is more profoundly influenced by human activities within watersheds rather than its composition. Moreover, the association between human activity and FML density exhibits greater significant compared to variations based on geography and seasonality. This study provides a scientific basis for coastal protection and contributes for understanding of the mechanisms of marine litter transfer from land to sea.

Pterostilbene attenuates microglial inflammation and brain injury after intracerebral hemorrhage in an OPA1-dependent manner.

Microglial activation and subsequent inflammatory responses are critical processes in aggravating secondary brain injury after intracerebral hemorrhage (ICH). Pterostilbene (3', 5'-dimethoxy-resveratrol) features antioxidant and anti-inflammation properties and has been proven neuroprotective. In this study, we aimed to explore whether Pterostilbene could attenuate neuroinflammation after experimental ICH, as well as underlying molecular mechanisms. Here, a collagenase-induced ICH in mice was followed by intraperitoneal injection of Pterostilbene (10 mg/kg) or vehicle once daily. PTE-treated mice performed significantly better than vehicle-treated controls in the neurological behavior test after ICH. Furthermore, our results showed that Pterostilbene reduced lesion volume and neural apoptosis, and alleviated blood-brain barrier (BBB) damage and brain edema. RNA sequencing and subsequent experiments showed that ICH-induced neuroinflammation and microglial proinflammatory activities were markedly suppressed by Pterostilbene treatment. With regard to the mechanisms, we identified that the anti-inflammatory effects of Pterostilbene relied on remodeling mitochondrial dynamics in microglia. Concretely, Pterostilbene reversed the downregulation of OPA1, promoted mitochondrial fusion, restored normal mitochondrial morphology, and reduced mitochondrial fragmentation and superoxide in microglia after OxyHb treatment. Moreover, conditionally deleting microglial OPA1 in mice largely countered the effects of Pterostilbene on alleviating microglial inflammation, BBB damage, brain edema and neurological impairment following ICH. In summary, we provided the first evidence that Pterostilbene is a promising agent for alleviating neuroinflammation and brain injury after ICH in mice, and uncovered a novel regulatory relationship between Pterostilbene and OPA1-mediated mitochondrial fusion.

A Six-Surface System to Describe Anatomy of Anterior Clinoid Process and Its Application in Anterior Clinoidectomy and Resection of Paraclinoid Meningioma.

OBJECTIVE: The anterior clinoid process (ACP) is surrounded by nerves and vessels that, together, constitute an intricate anatomical structure with variations that challenges the performance of individualized anterior clinoidectomy in treating lesions with different extents of invasion. In the present study, we established a 6-surface system for the ACP based on anatomical landmarks and analyzed its value in guiding ACP drilling and resection of paraclinoid meningiomas. METHODS: Using the anatomical characteristics of 10 dry skull specimens, we set 9 anatomical landmarks to delineate the ACP into 6 surfaces. Guided by our 6-surface system and eggshell technique, 5 colored silicone-injected anatomical specimens were dissected via a frontotemporal craniotomy to perform anterior clinoidectomy. Next, 3 typical cases of paraclinoid meningioma were selected to determine the value of using our 6-surface system in tumor resection. RESULTS: Nine points (A-H and T) were proposed to delineate the ACP surface into frontal, temporal, optic nerve, internal carotid artery, cranial nerve III, and optic strut surfaces according to the adjacent tissues. Either intradurally or extradurally, the frontal and temporal surfaces could be identified and drilled into depth, followed by skeletonization of the optic nerve, cranial nerve III, internal carotid artery, and optic strut surfaces. After the residual bone was removed, the ACP was drilled off. In surgery of paraclinoid meningiomas, our 6-surface system provided great benefit in locating the dura, nerves, and vessels, thus, increasing the safety of opening the optic canal and relaxing the oculomotor or optic nerves and allowing for individualized ACP drilling for meningioma removal. CONCLUSIONS: Our 6-surface system adds much anatomical information to the classic Dolenc triangle and can help neurosurgeons, especially junior ones, to increase their understanding of the paraclinoid spatial structure and accomplish individualized surgical procedures with high safety and minimal invasiveness.

Conditional survival nomogram for monitoring real-time survival of young non-metastatic nasopharyngeal cancer survivors.

BACKGROUND: The aim of this study was to clarify the improvement of the overall survival (OS) over time in young non-metastatic nasopharyngeal carcinoma (NPC) survivors by conditional survival (CS) analysis and to construct a CS-nomogram for updating individualized real-time prognosis. METHODS: The study included 3409 young non-metastatic NPC patients from the Surveillance, Epidemiology, and End Results (SEER) database (2004-2019). OS was estimated using the Kaplan-Meier method. CS was calculated based on CS(y|x) = OS(y + x)/OS(x), defined as the probability that a patient would survive for another y years after surviving for x years since diagnosis. We identified predictors using the least absolute shrinkage and selection operator (LASSO) regression and developed the CS-nomogram using multivariate Cox regression and the CS formula. RESULTS: CS analysis showed a continuous increase in 10-year OS for young non-metastatic NPC from the initial 60.4% to 65.0%, 70.2%, 74.2%, 78.2%, 82.6%, 86.9%, 91.1%, 96.2% and 97.0% (surviving 1-9 years after diagnosis, respectively). After screening by LASSO regression, age, race, marital status, histological type, T- and N-status were used as predictors to construct the CS-nomogram. The model accurately estimated the real-time prognosis of survivors during follow-up with a stable time-dependent area under the curve (AUC). CONCLUSIONS: CS analysis based on SEER database calibrated the real-time prognosis of young non-metastatic NPC survivors, revealing a dynamic improvement during follow-up time. We developed a novel CS-nomogram to update survival data for real-time optimization of monitoring strategies, medical resource allocation, and patient counseling. However, it was important to note that the model still needed external data validation and continuous improvement.

MiR-124 Reduced Neuroinflammation after Traumatic Brain Injury by Inhibiting TRAF6.

INTRODUCTION: Neuroinflammation contributes to secondary injury after traumatic brain injury (TBI), which has been mainly mediated by the microglia. MiR-124 was reported to play an important role in the polarization of microglia by targeting TLR4 signaling pathway. However, the role and mechanism of miR-124 in neuroinflammation mediated by microglia after TBI is unclear. To clarify this, we performed this research. METHODS: The expression of miR-124 was first measured by RT-PCR in the injured brain at 1/3/7 days post-TBI. Then, miR-124 mimics or inhibitors administration was used to interfere the expression of miR-124 at 24 h post-TBI. Subsequently, the microglia polarization markers were detected by RT-PCR, the expression of inflammatory cytokines was detected by ELISA, the expression of TLR4/MyD88/IRAK1/TRAF6/NF-κB was measured by WB, and the neurological deficit was evaluated by NSS and MWM test. At last, in vitro experiments were performed to explore the exact target molecule of miR-124 on TLR4 signaling pathway. RESULTS: Animal research indicated that the expression of miR-124 was downregulated after TBI. Upregulation of miR-124 promoted the M2 polarization of microglia and inhibited the activity of TLR4 pathway, as well as reduced neuroinflammation and neurological deficit after TBI. In vitro experiments indicated that miR-124 promoted the M2 polarization of microglia and reduced neuroinflammation by inhibiting TRAF6. CONCLUSION: This study demonstrated that upregulation of miR-124 promoted the M2 polarization of microglia and reduced neuroinflammation after TBI by inhibiting TRAF6.

P7C3-A20 Attenuates Microglial Inflammation and Brain Injury after ICH through Activating the NAD+/Sirt3 Pathway.

Intracerebral hemorrhage (ICH) is lethal but lacks effective therapies. Nicotinamide adenine dinucleotide (NAD+) is a central metabolite indispensable for a broader range of fundamental intracellular biological functions. Reduction of NAD+ usually occurs after acute brain insults, and supplementation of NAD+ has been proven neuroprotective. P7C3-A20 is a novel compound featuring its ability to facilitate the flux of NAD+. In this study, we sought to determine the potential therapeutic value of P7C3-A20 in ICH. In collagenase-induced ICH mouse models, we found that P7C3-A20 treatment could diminish lesion volume, reduce blood-brain barrier (BBB) damage, mitigate brain edema, attenuate neural apoptosis, and improve neurological outcomes after ICH. Further, RNA sequencing and subsequent experiments revealed that ICH-induced neuroinflammation and microglial proinflammatory activities were significantly suppressed following P7C3-A20 treatment. Mitochondrial damage is an important trigger of inflammatory response. We examined mitochondrial morphology and function and found that P7C3-A20 could attenuate OxyHb-induced impairment of mitochondrial dynamics and functions in vitro. Mechanistically, Sirt3, an NAD+-dependent deacetylase located in mitochondria, was then found to play a vital role in the protection of P7C3-A20 against mitochondrial damage and inflammatory response. In rescue experiments, P7C3-A20 failed to exert those protective effects in microglia-specific Sirt3 conditional knockout (CKO) mice. Finally, preclinical research revealed a correlation between the plasma NAD+ level and the neurological outcome in ICH patients. These results demonstrate that P7C3-A20 is a promising therapeutic agent for neuroinflammatory injury after ICH and exerts protective actions, at least partly, in a Sirt3-dependent manner.

Establishment of transgenic pigs overexpressing human PKD2-D511V mutant.

Numerous missense mutations have been reported in autosomal dominant polycystic kidney disease which is one of the most common renal genetic disorders. The underlying mechanism for cystogenesis is still elusive, partly due to the lack of suitable animal models. Currently, we tried to establish a porcine transgenic model overexpressing human PKD2-D511V (hPKD2-D511V), which is a dominant-negative mutation in the vertebrate in vitro models. A total of six cloned pigs were finally obtained using somatic cell nuclear transfer. However, five with functional hPKD2-D511V died shortly after birth, leaving only one with the dysfunctional transgenic event to survive. Compared with the WT pigs, the demised transgenic pigs had elevated levels of hPKD2 expression at the mRNA and protein levels. Additionally, no renal malformation was observed, indicating that hPKD2-D511V did not alter normal kidney development. RNA-seq analysis also revealed that several ADPKD-related pathways were disturbed when overexpressing hPKD2-D511V. Therefore, our study implies that hPKD2-D511V may be lethal due to the dominant-negative effect. Hence, to dissect how PKD2-D511V drives renal cystogenesis, it is better to choose in vitro or invertebrate models.

Contactless Credit Cards Payment Fraud Protection by Ambient Authentication.

In recent years, improvements to the computational ability of mobile phones and support for near-field-communication have enabled transactions to be performed by using mobile phones to emulate a credit card or by using quick response codes. Thus, users need not carry credit cards but can simply use their mobile phones. However, the Europay MasterCard Visa (EMV) protocol is associated with a number of security concerns. In contactless transactions, attackers can make purchases by launching a relay attack from a distance. To protect message transmission and prevent relay attacks, we propose a transaction protocol that is compatible with EMV protocols and that can perform mutual authentication and ambient authentication on near-field-communication-enabled mobile phones. Through mutual authentication, our protocol ensures the legitimacy of transactions and establishes keys for a transaction to protect the subsequent messages, thereby avoiding security problems in EMV protocols, such as man-in-the-middle attacks, skimming, and clone attacks on credit cards. By using ambient factors, our protocol verifies whether both transacting parties are located in the same environment, and it prevents relay attacks in the transaction process.

Single-Nucleus RNA Sequencing Reveals that Decorin Expression in the Amygdala Regulates Perineuronal Nets Expression and Fear Conditioning Response after Traumatic Brain Injury.

Traumatic brain injury (TBI) is a risk factor for posttraumatic stress disorder (PTSD). Augmented fear is a defining characteristic of PTSD, and the amygdala is considered the main brain region to process fear. The mechanism by which the amygdala is involved in fear conditioning after TBI is still unclear. Using single-nucleus RNA sequencing (snRNA-seq), transcriptional changes in cells in the amygdala after TBI are investigated. In total, 72 328 nuclei are obtained from the sham and TBI groups. 7 cell types, and analysis of differentially expressed genes (DEGs) reveals widespread transcriptional changes in each cell type after TBI are identified. In in vivo experiments, it is demonstrated that Decorin (Dcn) expression in the excitatory neurons of the amygdala significantly increased after TBI, and Dcn knockout in the amygdala mitigates TBI-associated fear conditioning. Of note, this effect is caused by a Dcn-mediated decrease in the expression of perineuronal nets (PNNs), which affect the glutamate-γ-aminobutyric acid balance in the amygdala. Finally, the results suggest that Dcn functions by interacting with collagen VI α3 (Col6a3). Consequently, the findings reveal transcriptional changes in different cell types of the amygdala after TBI and provide direct evidence that Dcn relieves fear conditioning by regulating PNNs.

Computed tomographic parameters correlate with coagulation disorders in isolated traumatic brain injury.

BACKGROUND AND OBJECTIVE: The imbalanced hemostatic equilibrium caused by brain tissue or vessel damage underlies the pathophysiology of traumatic brain injury (TBI)-induced coagulopathy, and cranial computed tomography (CT) is the gold standard for evaluating brain injury. The present study aimed to explore the correlation between quantitative cranial CT parameters and coagulopathy after TBI. METHODS: We retrospectively collected the medical records of TBI patients with extracranial abbreviated injury scale (AIS) scores <3 who were admitted to our institution. The quantitative cranial CT parameters of patients with and without coagulopathy were compared, and univariate correlation analysis between CT parameters and coagulation subtest values and platelet counts was performed. The predictors for each subtest of coagulation function were probed by multivariate regression. RESULTS: TBI patients with coagulopathy had a larger intracerebral haematoma/contusion (ICH/C) volume (p < 0.001), a higher incidence of compressed basal cisterns (p = 0.015), a higher Graeb score (p < 0.001) and subarachnoid haematoma (Fisher's scaling score) (p = 0.019) than those without coagulopathy. IH/C volume was identified as an independent risk factor for predicting coagulopathy. ICH/C volume showed a significantly positive correlation with APTT (Pearson's correlation = 0.333, p < 0.001), while a significant negative correlation with PLT (Pearson's correlation = - 0.312, p < 0.001). CONCLUSION: ICH/C volume was a main quantitative cranial CT parameter for predicting coagulopathy, suggesting that parenchymal brain damage and vessel injury were closely associated with coagulopathy after TBI.

A CAN-Bus Lightweight Authentication Scheme.

The design of the Controller Area Network (CAN bus) did not account for security issues and, consequently, attacks often use external mobile communication interfaces to conduct eavesdropping, replay, spoofing, and denial-of-service attacks on a CAN bus, posing a risk to driving safety. Numerous studies have proposed CAN bus safety improvement techniques that emphasize modifying the original CAN bus method of transmitting frames. These changes place additional computational burdens on electronic control units cause the CAN bus to lose the delay guarantee feature. Consequently, we proposed a method that solves these compatibility and security issues. Simple and efficient frame authentication algorithms were used to prevent spoofing and replay attacks. This method is compatible with both CAN bus and CAN-FD protocols and has a lower operand when compared with other methods.

Acrolein Induces Systemic Coagulopathy via Autophagy-dependent Secretion of von Willebrand Factor in Mice after Traumatic Brain Injury.

Traumatic brain injury (TBI)-induced coagulopathy has increasingly been recognized as a significant risk factor for poor outcomes, but the pathogenesis remains poorly understood. In this study, we aimed to investigate the causal role of acrolein, a typical lipid peroxidation product, in TBI-induced coagulopathy, and further explore the underlying molecular mechanisms. We found that the level of plasma acrolein in TBI patients suffering from coagulopathy was higher than that in those without coagulopathy. Using a controlled cortical impact mouse model, we demonstrated that the acrolein scavenger phenelzine prevented TBI-induced coagulopathy and recombinant ADAMTS-13 prevented acrolein-induced coagulopathy by cleaving von Willebrand factor (VWF). Our results showed that acrolein may contribute to an early hypercoagulable state after TBI by regulating VWF secretion. mRNA sequencing (mRNA-seq) and transcriptome analysis indicated that acrolein over-activated autophagy, and subsequent experiments revealed that acrolein activated autophagy partly by regulating the Akt/mTOR pathway. In addition, we demonstrated that acrolein was produced in the perilesional cortex, affected endothelial cell integrity, and disrupted the blood-brain barrier. In conclusion, in this study we uncovered a novel pro-coagulant effect of acrolein that may contribute to TBI-induced coagulopathy and vascular leakage, providing an alternative therapeutic target.

Death after discharge: prognostic model of 1-year mortality in traumatic brain injury patients undergoing decompressive craniectomy.

BACKGROUND: Despite advances in decompressive craniectomy (DC) for the treatment of traumatic brain injury (TBI), these patients are at risk of having a poor long-term prognosis. The aim of this study was to predict 1-year mortality in TBI patients undergoing DC using logistic regression and random tree models. METHODS: This was a retrospective analysis of TBI patients undergoing DC from January 1, 2015, to April 25, 2019. Patient demographic characteristics, biochemical tests, and intraoperative factors were collected. One-year mortality prognostic models were developed using multivariate logistic regression and random tree algorithms. The overall accuracy, sensitivity, specificity, and area under the receiver operating characteristic curves (AUCs) were used to evaluate model performance. RESULTS: Of the 230 patients, 70 (30.4%) died within 1 year. Older age (OR, 1.066; 95% CI, 1.045-1.087; P < 0.001), higher Glasgow Coma Score (GCS) (OR, 0.737; 95% CI, 0.660-0.824; P < 0.001), higher D-dimer (OR, 1.005; 95% CI, 1.001-1.009; P = 0.015), coagulopathy (OR, 2.965; 95% CI, 1.808-4.864; P < 0.001), hypotension (OR, 3.862; 95% CI, 2.176-6.855; P < 0.001), and completely effaced basal cisterns (OR, 3.766; 95% CI, 2.255-6.290; P < 0.001) were independent predictors of 1-year mortality. Random forest demonstrated better performance for 1-year mortality prediction, which achieved an overall accuracy of 0.810, sensitivity of 0.833, specificity of 0.800, and AUC of 0.830 on the testing data compared to the logistic regression model. CONCLUSIONS: The random forest model showed relatively good predictive performance for 1-year mortality in TBI patients undergoing DC. Further external tests are required to verify our prognostic model.

Single-Cell RNA Sequencing With Combined Use of Bulk RNA Sequencing to Reveal Cell Heterogeneity and Molecular Changes at Acute Stage of Ischemic Stroke in Mouse Cortex Penumbra Area.

Stroke has been the leading cause of adult morbidity and mortality over the past several years. After an ischemic stroke attack, many dormant or reversibly injured brain cells exist in the penumbra area. However, the pathological processes and unique cell information in the penumbra area of an acute ischemic stroke remain elusive. We applied unbiased single cell sequencing in combination with bulk RNA-seq analysis to investigate the heterogeneity of each cell type in the early stages of ischemic stroke and to detect early possible therapeutic targets to help cell survival. We used these analyses to study the mouse brain penumbra during this phase. Our results reveal the impact of ischemic stroke on specific genes and pathways of different cell types and the alterations of cell differentiation trajectories, suggesting potential pathological mechanisms and therapeutic targets. In addition to classical gene markers, single-cell genomics demonstrates unique information on subclusters of several cell types and metabolism changes in an ischemic stroke. These findings suggest that Gadd45b in microglia, Cyr61 in astrocytes, and Sgk3 in oligodendrocytes may play a subcluster-specific role in cell death or survival in the early stages of ischemic stroke. Moreover, RNA-scope multiplex in situ hybridization and immunofluorescence staining were applied to selected target gene markers to validate and confirm the existence of these cell subtypes and molecular changes during acute stage of ischemic stroke.

20-HETE synthesis inhibition attenuates traumatic brain injury-induced mitochondrial dysfunction and neuronal apoptosis via the SIRT1/PGC-1α pathway: A translational study.

OBJECTIVES: 20-hydroxyeicosatetraenoic acid (20-HETE) is a metabolite of arachidonic acid catalysed by cytochrome P450 enzymes and plays an important role in cell death and proliferation. We hypothesized that 20-HETE synthesis inhibition may have protective effects in traumatic brain injury (TBI) and investigated possible underlying molecular mechanisms. MATERIALS AND METHODS: Neurologic deficits, and lesion volume, reactive oxygen species (ROS) levels and cell death as assessed using immunofluorescence staining, transmission electron microscopy and Western blotting were used to determine post-TBI effects of HET0016, an inhibitor of 20-HETE synthesis, and their underlying mechanisms. RESULTS: The level of 20-HETE was found to be increased significantly after TBI in mice. 20-HETE synthesis inhibition reduced neuronal apoptosis, ROS production and damage to mitochondrial structures after TBI. Mechanistically, HET0016 decreased the Drp1 level and increased the expression of Mfn1 and Mfn2 after TBI, indicating a reversal of the abnormal post-TBI mitochondrial dynamics. HET0016 also promoted the restoration of SIRT1 and PGC-1α in vivo, and a SIRT1 activator (SRT1720) reversed the downregulation of SIRT1 and PGC-1α and the abnormal mitochondrial dynamics induced by 20-HETE in vitro. Furthermore, plasma 20-HETE levels were found to be higher in TBI patients with unfavourable neurological outcomes and were correlated with the GOS score. CONCLUSIONS: The inhibition of 20-HETE synthesis represents a novel strategy to mitigate TBI-induced mitochondrial dysfunction and neuronal apoptosis by regulating the SIRT1/PGC-1α pathway.

Antagonism of Protease-Activated Receptor 4 Protects Against Traumatic Brain Injury by Suppressing Neuroinflammation via Inhibition of Tab2/NF-κB Signaling.

Traumatic brain injury (TBI) triggers the activation of the endogenous coagulation mechanism, and a large amount of thrombin is released to curb uncontrollable bleeding through thrombin receptors, also known as protease-activated receptors (PARs). However, thrombin is one of the most critical factors in secondary brain injury. Thus, the PARs may be effective targets against hemorrhagic brain injury. Since the PAR1 antagonist has an increased bleeding risk in clinical practice, PAR4 blockade has been suggested as a more promising treatment. Here, we explored the expression pattern of PAR4 in the brain of mice after TBI, and explored the effect and possible mechanism of BMS-986120 (BMS), a novel selective and reversible PAR4 antagonist on secondary brain injury. Treatment with BMS protected against TBI in mice. mRNA-seq analysis, Western blot, and qRT-PCR verification in vitro showed that BMS significantly inhibited thrombin-induced inflammation in astrocytes, and suggested that the Tab2/ERK/NF-κB signaling pathway plays a key role in this process. Our findings provide reliable evidence that blocking PAR4 is a safe and effective intervention for TBI, and suggest that BMS has a potential clinical application in the management of TBI.