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Background: Excitotoxicity is a process in which NADPH oxidase-2 (NOX-2) plays a pivotal role in the generation of reactive oxygen species (ROS). Oxidative stress influences the expression of Aquaporin 4 (AQP4), a water channel implicated in blood-brain barrier (BBB) permeability and edema formation. The endocannabinoid system is widely distributed in the brain, particularly through the cannabinoid receptor type 1 (CB1) and type 2 (CB2), which have been shown to have a neuroprotective function in brain injury. Given the significant involvement of NOX-2 in ROS production during excitotoxicity, our research aims to assess the participation of NOX-2 in the neuroprotective effect of the cannabinoid receptor agonist WIN55,212-2 against glutamate-induced excitotoxicity damage in the striatum using in vivo model., Methods: Wild-type mice (C57BL/6) and NOX-2 KO (gp91 Cybbtm1Din/J ) were stereotactically injected in the striatum with monosodium glutamate or vehicle. Subsequently, a group of mice was administered an intraperitoneal dose of WIN55,212-2, AM251, or AM251/WIN55,212-2 following the intracerebral injection. Motor activity was assessed, and the lesion was examined through histological sections stained with cresyl violet. Additionally, brain water content and Evans blue assay were conducted. The activity of NOX was quantified, and the protein expression of CB1, gp91 phox , AQP4, Iba-1, TNF-α, and NF-κB was analyzed using Western blot. Furthermore, ROS formation was measured through the DHE assay., Results: The activation of the endocannabinoid receptors demonstrated a neuroprotective response during excitotoxicity, meditated by NOX-2. The reduction in ROS production led to a decrease in neuroinflammation, and AQP4 expression, resulting in reduced edema formation, and BBB permeability., Conclusions: During excitotoxic damage, WIN55,212-2 inhibits NOX-2-induced ROS production, reducing brain injury., (© 2024 The Author(s). CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Ischemic stroke resulting from blockade of brain vessels lacks effective treatments, prompting exploration for potential therapies. Among promising candidates, microRNA-149 (miR-149) has been investigated for its role in alleviating oxidative stress, inflammation, and neurodegeneration associated with ischemic conditions. To evaluate its therapeutic effect, male Wistar rats were categorized into five groups, each consisting of 27 rats: sham, MCAO, lentiviral control, lentiviral miR-149, and miR149-5p mimic. Treatments were microinjected intracerebroventricularly (ICV) (right side), and ischemia was induced using middle cerebral artery occlusion (MCAO) procedure. Post-MCAO, neurological function, histopathological changes, blood-brain barrier (BBB) permeability, cerebral edema, and mRNA levels of Fas ligand (Faslg) and glutamate ionotropic NMDA receptor 1 (GRIN1) were assessed, alongside biochemical assays. MiR-149 administration improved neurological function, reduced brain damage, preserved BBB integrity, and attenuated cerebral edema. Upregulation of miR149-5p decreased Faslg and GRIN1 expression in ischemic brain regions. MiR-149 also reduced oxidative stress, enhanced antioxidant activity, decreased caspase-1 and - 3 activity, and modulated inflammatory factors in ischemic brain regions. Moreover, DNA fragmentation as an index of cell death decreased following miR-149 treatment. In conclusion, the study underscores miR-149 potential as a neuroprotective agent against ischemic stroke, showcasing its efficacy in modulating various mechanisms and supporting its candidacy as a promising therapeutic target for innovative strategies in stroke treatment., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Oxidative stress and neuroapoptosis are significant pathological processes that occur in response to intracerebral hemorrhage (ICH), however, the optimal therapeutic strategy to treat these responses remains unknown. Pterostilbene (PTE) influences neural cell survival in in the pathology of a number of neurological diseases, but the mechanisms underlying this influence at present are not clear. The objective of the present study was to examine the potential impact of PTE on mitigating oxidative stress and neuronal apoptosis following ICH, while also elucidating the potential underlying pathways., Material & Method: For in vivo experimentation, male C57BL/6 mice were used to establish ICH models. Wet-to-dry weight ratios were utilized to assess the degree of cerebral edema in the context of PTE intervention. Behavioral experiments were conducted to evaluate neurological dysfunction and cognitive impairment, and hematoxylin and eosin staining was employed to observe histopathological changes in the brain. Furthermore, oxidative stress levels in hippocampal tissues were measured, and cell apoptosis was examined using TUNEL staining and western blotting techniques. In vitro experiments were conducted to evaluate the extent of oxidative stress and neural apoptosis after sirtuin 1 (SIRT1) siRNA treatment. Immunofluorescence cytochemistry was used to analyze the immunofluorescence colocalization of SIRT1 and NeuN., Result: Mice that experienced ICH exhibited worsening neurological deterioration, increased oxidative stress and neuronal cell apoptosis. However, the addition of PTE was found to lessen these effects. Furthermore, PTE was found to activate the SIRT1-mediated Nrf2 pathway in mice with ICH. When SIRT1 was inhibited, levels of oxidative stress and neuronal apoptosis increased, even in the presence of PTE., Conclusion: The present study provided evidence to indicate that PTE can suppress oxidative damage and neuronal apoptosis following ICH by activating the SIRT1/Nrf2 pathway., Competing Interests: Declaration of competing interest Authors report no conflict of interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Following ischemic stroke astrocytes undergo rapid molecular and functional changes that may accentuate tissue damage. In this study we identified the neurotrophin receptor TrkB in astrocytes as a key promoter of acute CNS injury in ischemic stroke. In fact, TrkB protein was strongly upregulated in astrocytes after human and experimental stroke, and transgenic mice lacking astrocyte TrkB displayed significantly smaller lesion volume, lower brain atrophy and better motor performance than control animals after transient middle cerebral artery occlusion. Neuropathological studies evidenced that edema directly correlated with astrogliosis and was limited in transgenic mice. Importantly, adaptive levels of the water channel AQP4 was astrocyte TrkB-dependent as AQP4 upregulation after stroke did not occur in mice lacking astrocyte TrkB. In vitro experiments with wild-type and/or TrkB-deficient astrocytes highlighted TrkB-dependent upregulation of AQP4 via activation of HIF1-alpha under hypoxia. Collectively, our observations indicate that TrkB signaling in astrocytes contributes to the development of edema and worsens cerebral ischemia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The water channel aquaporin-4 (AQP4) is crucial for water balance in the mammalian brain. AQP4 has two main canonical isoforms, M23, which forms supramolecular structures called Orthogonal Arrays of Particles (OAP) and M1, which does not, along with two extended isoforms (M23ex and M1ex). This study examines these isoforms' roles, particularly AQP4ex, which influences water channel activity and localization at the blood-brain barrier. Using mice lacking both AQP4ex isoforms (AQP4ex-KO) and lacking both AQP4M23 isoforms (OAP-null) mice, we explored brain water dynamics under osmotic stress induced by an acute water intoxication (AWI) model. AQP4ex-KO mice had lower basal brain water content than WT and OAP-null mice. During AWI, brain water content increased rapidly in WT and AQP4ex-KO mice, but was delayed in OAP-null mice. AQP4ex-KO mice had the highest water content increase at 20 min. Immunoblot analysis showed stable total AQP4 in WT mice initially, with increases at 30 min. AQP4ex and its phosphorylated form (p-AQP4ex) levels rose quickly, but the p-AQP4ex/AQP4ex ratio dropped at 20 min. AQP4ex-KO mice showed a compensatory rise in canonical AQP4 at 20 min post-AWI. These findings highlight the important role of AQP4ex in water content dynamics in both normal and pathological states. To evaluate brain waste clearance, amyloid-β (Aβ) removal was assessed using a fluorescent Aβ intra-parenchyma injection model. AQP4ex-KO mice demonstrated markedly impaired Aβ clearance, with extended diffusion distances and reduced fluorescence in cervical lymph nodes, indicating inefficient drainage from the brain parenchyma. Mechanistically, the polarization of AQP4 at astrocytic endfeet is essential for efficient clearance flow, aiding interstitial fluid movement into the CSF and lymphatic system. In AQP4ex-KO mice, disrupted polarization forces reliance on slower, passive diffusion for solute clearance, significantly reducing Aβ removal efficiency and altering extracellular space dynamics. Our results underscore the importance of AQP4ex in both brain water homeostasis and solute clearance, particularly Aβ. These findings highlight AQP4ex as a potential therapeutic target for enhancing waste clearance mechanisms in the brain, which could have significant implications for treating brain edema and neurodegenerative diseases like Alzheimer's., (© 2024. The Author(s).)

Neuronal cytotoxic edema is implicated in neuronal injury and death, yet mitigating brain edema with osmotic and surgical interventions yields poor clinical outcomes. Importantly, neuronal swelling and its downstream consequences during early brain development remain poorly investigated, and new treatment approaches are needed. We explored Ca 2+ -dependent downstream effects after neuronal cytotoxic edema caused by diverse injuries in mice of both sexes using multiphoton Ca 2+ imaging in vivo [Postnatal Day (P)12-17] and in acute brain slices (P8-12). After different excitotoxic insults, cytosolic GCaMP6s translocated into the nucleus after a few minutes in a subpopulation of neurons, persisting for hours. We used an automated morphology-detection algorithm to detect neuronal soma and quantified the nuclear translocation of GCaMP6s as the nuclear to cytosolic intensity ( N / C ratio). Elevated neuronal N / C ratios occurred concurrently with persistent elevation in Ca 2+ loads and could also occur independently from neuronal swelling. Electron microscopy revealed that the nuclear translocation was associated with the increased nuclear pore size. The nuclear accumulation of GCaMP6s in neurons led to neocortical circuit dysfunction, mitochondrial pathology, and increased cell death. Inhibiting calpains, a family of Ca 2+ -activated proteases, prevented elevated N / C ratios and neuronal swelling. In summary, in the developing brain, we identified a calpain-dependent alteration of nuclear transport in a subpopulation of neurons after disease-relevant insults leading to long-term circuit dysfunction and cell death. The nuclear translocation of GCaMP6 and other cytosolic proteins after acute excitotoxicity can be an early biomarker of brain injury in the developing brain., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 the authors.)

Traumatic brain injury (TBI) can lead to short-term and long-term physical and cognitive impairments, which have significant impacts on patients, families, and society. Currently, treatment outcomes for this disease are often unsatisfactory, due at least in part to the fact that the molecular mechanisms underlying the development of TBI are largely unknown. Here, we observed significant upregulation of Piezo2, a key mechanosensitive ion channel protein, in the injured brain tissue of a mouse model of TBI induced by controlled cortical impact. Pharmacological inhibition and genetic knockdown of Piezo2 after TBI attenuated neuronal death, brain edema, brain tissue necrosis, and deficits in neural function and cognitive function. Mechanistically, the increase in Piezo2 expression contributed to TBI-induced neuronal death and subsequent production of TNF-α and IL-1β, likely through activation of the RhoA/ROCK1 pathways in the central nervous system. Our findings suggest that Piezo2 is a key player in and a potential therapeutic target for TBI., (© 2024. The Author(s).)

Oxidative stress (OS) is the main cause of secondary damage following intracerebral hemorrhage (ICH). The polarity expression of aquaporin-4 (AQP4) has been shown to be important in maintaining the homeostasis of water transport and preventing post-injury brain edema in various neurological disorders. This study primarily aimed to investigate the effect of the oxygen free radical scavenger, edaravone, on AQP4 polarity expression in an ICH mouse model and determine whether it involves in AQP4 polarity expression via the OS/MMP9/β-dystroglycan (β-DG) pathway. The ICH mouse model was established by autologous blood injection into the basal nucleus. Edaravone or the specific inhibitor of matrix metalloproteinase 9 (MMP9), MMP9-IN-1, called MMP9-inh was administered 10 min after ICH via intraperitoneal injection. ELISA detection, neurobehavioral tests, dihydroethidium staining (DHE staining), intracisternal tracer infusion, hematoxylin and eosin (HE) staining, immunofluorescence staining, western blotting, Evans blue (EB) permeability assay, and brain water content test were performed. The results showed that OS was exacerbated, AQP4 polarity was lost, drainage function of brain fluids was damaged, brain injury was aggravated, expression of AQP4, MMP9, and GFAP increased, while the expression of β-DG decreased after ICH. Edaravone reduced OS, restored brain drainage function, reduced brain injury, and downregulated the expression of AQP4, MMP9. Both edaravone and MMP9-inh alleviated brain edema, maintained blood-brain barrier (BBB) integrity, mitigated the loss of AQP4 polarity, downregulated GFAP expression, and upregulated β-DG expression. The current study suggests that edaravone can maintain AQP4 polarity expression by inhibiting the OS /MMP9/β-DG pathway after ICH., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Bezafibrate (BEZ) has displayed a wide range of neuroprotective effects in different types of neurological diseases. However, its pharmacological function in traumatic brain injury (TBI) is still unknown. In the current study, a TBI model was constructed in mice to examine the potential beneficial roles of BEZ. After TBI, mice were daily dieted with BEZ or vehicle solution. The motor function, learning and memory, brain edema, vascular inflammatory factors, the integrity of the blood-brain barrier (BBB), and the expression of the tight junction zona occludens 1 (ZO-1) were assessed. The findings demonstrate that after TBI, BEZ treatment significantly promoted the recovery of motor function and cognitive function deficits. Moreover, BEZ attenuated brain edema by reducing the levels of brain water content. We also found that administration of BEZ alleviated cerebral vascular pro-inflammation by suppressing the expression of ICAM-1, VCAM-1, and E-selectin. Notably, BEZ improved the impaired BBB integrity in TBI mice by restoring the expression of the tight junction (TJ) protein ZO-1. Further in vitro experiments show that treatment with BEZ prevented the aggravation of endothelial permeability and restored the reduction of trans-epithelial electrical resistance (TEER) as well as the expression of ZO-1 in TBI-exposed brain bEnd.3 cells. Mechanistically, we prove that the protective effects of BEZ are mediated by AMPK. Based on these findings, we conclude that BEZ improves TBI-induced BBB injury and it might be considered for the treatment or management of TBI., (Copyright © 2024. Published by Elsevier Ltd.)

Vasogenic brain edema, a potentially life-threatening consequence following an acute ischemic stroke, is a major clinical problem. This research aims to explore the therapeutic benefits of nimodipine, a calcium channel blocker, in mitigating vasogenic cerebral edema and preserving blood-brain barrier (BBB) function in an ischemic stroke rat model. In this research, animals underwent the induction of ischemic stroke via a 60-min blockage of the middle cerebral artery and treated with a nonhypotensive dose of nimodipine (1 mg/kg/day) for a duration of five days. The wet/dry method was employed to identify cerebral edema, and the Evans blue dye extravasation technique was used to assess the permeability of the BBB. Furthermore, immunofluorescence staining was utilized to assess the protein expression levels of matrix metalloproteinase-9 (MMP-9) and intercellular adhesion molecule-1 (ICAM-1). The study also examined mitochondrial function by evaluating mitochondrial swelling, succinate dehydrogenase (SDH) activity, the collapse of mitochondrial membrane potential (MMP), and the generation of reactive oxygen species (ROS). Post-stroke administration of nimodipine led to a significant decrease in cerebral edema and maintained the integrity of the BBB. The protective effects observed were associated with a reduction in cell apoptosis as well as decreased expression of MMP-9 and ICAM-1. Furthermore, nimodipine was observed to reduce mitochondrial swelling and ROS levels while simultaneously restoring MMP and SDH activity. These results suggest that nimodipine may reduce cerebral edema and BBB breakdown caused by ischemia/reperfusion. This effect is potentially mediated through the reduction of MMP-9 and ICAM-1 levels and the enhancement of mitochondrial function., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The destruction of the blood-brain barrier and damage to the gastrointestinal mucosa after intracerebral hemorrhage (ICH) are important reasons for its high disability and mortality rates. However, the exact etiology is not yet clear. In addition, there are currently no effective treatments for improving cerebral edema and gastric mucosal damage after ICH. Trefoil factor 1 (TFF1) is a secretory protein that plays a crucial role in maintaining the integrity and barrier function of the gastric mucosa, and it has been reported to have a protective effect on brain damage induced by various causes. This study utilized a rat model of ICH induced by type IV collagenase was utilized, and intervened with recombinant TFF1 protein from an external institute to investigate the protective mechanisms of TFF1 against brain edema and gastric mucosal damage after ICH. The results demonstrated that TFF1 alleviated the neurological function and gastric mucosal damage in the rat model of ICH induced by type IV collagenase. TFF1 may ensure the integrity of the blood-brain and gastric mucosal barriers by regulating the EGFR (epidermal growth factor receptor)/Src (non-receptor tyrosine kinase)/FAK (focal adhesion kinase) pathway. Clearly, the disruption of the blood-brain barrier and the destruction of the gastric mucosal barrier are key pathological features of ICH, and TFF1 can improve the progression of blood-brain barrier and gastric mucosal barrier disruption in ICH by regulating the EGFR/Src/FAK pathway. Therefore, TFF1 may be a potential target for the treatment of ICH., Competing Interests: Declaration of competing interest The authors state that there are no conflicts of interest to disclose., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Current clinical practice primarily relies on surgical intervention to remove hematomas in patients with intracerebral hemorrhage (ICH), given the lack of effective drug therapies. Previous research indicates that simvastatin (SIM) may enhance hematoma absorption and resolution in the acute phase of ICH, though the precise mechanisms remain unclear. Recent findings have highlighted the glymphatic system (GS) as a crucial component in intracranial cerebrospinal fluid circulation, playing a significant role in hematoma clearance post-ICH. This study investigates the link between SIM efficacy in hematoma resolution and the GS. Our experimental results show that SIM alleviates GS damage in ICH-induced rats, resulting in improved outcomes such as reduced brain edema, neuronal apoptosis, and degeneration. Further analysis reveals that SIM's effects are mediated through the VEGF-C/VEGFR3/PI3K-Akt pathway. This study advances our understanding of SIM's mechanism in promoting intracranial hematoma clearance and underscores the potential of targeting the GS for ICH treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

To explore the impacts of intestinal flora on cerebral hemorrhage area and brain tissue inflammation in acute hemorrhagic stroke, seventy-two male C57BL/6 mice were randomly separated into 6 groups (n=12), the experimental group (EG, day 1, day 3 and day 7) and the control group (CG, day 1, day 3 and day 7). The mouse cerebral hemorrhage model was established by collagenase injection, and the EG received 0.4 mL fecal filtrate of healthy mice once a day, and the CG received the same amount of normal saline transplantation. The mNSS score, hematoma volume and cerebral edema content were used to evaluate nerve function injury and brain injury degree at each time point after operation. The expressions of inflammatory factors were detected by western blot. We found that at each time point after operation, compared with the CG, nerve function deficit scores of mice in the EG declined (P<0.05), the water content of mice brain tissue in the EG declined (P<0.05), and the protein expressions of inflammatory factors in the EG were decreased (P<0.05). Relative to the CG, the volume of hematoma in the EG declined on day 3 along with day 7 after operation (P<0.05). In conclusion, intestinal flora can reduce cerebral hemorrhage area and brain tissue inflammation, and then improve the performance of nerve function deficit in acute hemorrhagic stroke.

Aims: Incidence of acute mountain sickness (AMS) ranges from 40%-90%, with high-altitude cerebral edema (HACE) representing a life-threatening end stage of severe AMS. However, practical and convenient preventive strategies for HACE are lacking. Remote ischemic preconditioning (RIPC) has demonstrated preventive effects on ischemia- or hypoxia-induced cardiovascular and cerebrovascular diseases. This study aimed to investigate the potential molecular mechanism of HACE and the application of RIPC in preventing HACE onset., Methods: A hypobaric hypoxia chamber was used to simulate a high-altitude environment of 7000 meters. Metabolomics and metabolic flux analysis were employed to assay metabolite levels. Transcriptomics and quantitative real-time PCR (q-PCR) were used to investigate gene expression levels. Immunofluorescence staining was performed on neurons to label cellular proteins. The fluorescent probes Mito-Dendra2, iATPSnFR1.0, and CMTMRos were used to observe mitochondria, ATP, and membrane potential in cultured neurons, respectively. TUNEL staining was performed to detect and quantify apoptotic cell death. Hematoxylin and eosin (H&E) staining was utilized to analyze pathological changes, such as tissue swelling in cerebral cortex samples. The Rotarod test was performed to assess motor coordination and balance in rats. Oxygen-glucose deprivation (OGD) of cultured cells was employed as an in vitro model to simulate the hypoxia and hypoglycemia induced by RIPC in animal experiments., Results: We revealed a causative perturbation of glucose metabolism in the brain preceding cerebral edema. Ischemic preconditioning treatment significantly reprograms glucose metabolism, ameliorating cell apoptosis and hypoxia-induced energy deprivation. Notably, ischemic preconditioning improves mitochondrial membrane potential and ATP production through enhanced glucose-coupled mitochondrial metabolism. In vivo studies confirm that RIPC alleviates cerebral edema, reduces cell apoptosis induced by high-altitude hypoxia, and improves motor dysfunction resulting from cerebral edema., Conclusions: Our study elucidates the metabolic basis of HACE pathogenesis. This study provides a new strategy for preventing HACE that RIPC reduces brain edema through reprogramming metabolism, highlighting the potential of targeting metabolic reprogramming for neuroprotective interventions in neurological diseases caused by ischemia or hypoxia., (© 2024 The Author(s). CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Ischemic stroke occurs due a blockage in the blood flow to the brain, leading to damage to the nervous system. The prevalent morbidities resulting from stroke include post-stroke infection, as sepsis. Additionally, oxidative stress is recognized for inducing functional deficits in peripheral organs during sepsis. Therefore, sex differences in stroke exist and we aimed to investigate the peripheral oxidative stress caused by sepsis after stroke in male and female rats. Wistar rats (male and female) were divided into sham+sham, middle cerebral artery occlusion (MCAO) + sham, sham+ cecal ligation and perforation (CLP) and MCAO+CLP groups to males and female rats. Animals were subjected to MCAO or sham and after 7 days, were subjected to sepsis by CLP or sham. After 24 h, serum, total brain, lung, liver, heart, and spleen were collected. Brain edema, myeloperoxidase (MPO) activity, nitrite/nitrate (N/N) concentration, oxidative damage to lipids and proteins, and catalase activity were evaluated. Brain edema was observed only in male rats in MCAO+CLP group compared to MCAO+sham. Regarding MPO activity, an increase was verified in male in different organs and serum in MCAO+CLP group. For N/N levels, the increase was more pronounced in females submitted to MCAO+CLP. In general, to oxidative stress, an increase was only observed in animals exposed to MCAO+CLP, or with a greater increase in this group compared to the others. The findings provided the first indication that animals exposed to MCAO exhibit a heightened vulnerability to the harmful impacts of sepsis, as evidenced by brain edema and peripheral oxidative stress, and this susceptibility is dependent of sex., Competing Interests: Declaration of competing interest None of the authors or funding sources has conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Brain edema is a critical complication arising from stroke and traumatic brain injury (TBI) with an important impact on patient recovery and can lead to long-term consequences. Therapeutic options to reduce edema progression are limited with variable patient outcomes. Aquaporin 4 (AQP4) is a water channel that allows bidirectional water diffusion across the astrocyte membrane and participates in the distinct phases of cerebral edema. The absence or inhibition of this channel has been demonstrated to ameliorate edema and brain damage. The endocannabinoid system (ECS) is a neuromodulator system with a wide expression in the brain and its activation has shown neuroprotective properties in diverse models of neuronal damage. This review describes and discusses the major features of ECS and AQP4 and their role during brain damage, observing that ECS stimulation reduces edema and injury size in diverse models of brain damage, however, the relationship between AQP4 expression and dynamics and ECS activation remains unclear. The research on these topics holds promising therapeutic implications for the treatment of brain edema following stroke and TBI., (© 2024. The Author(s).)

High-altitude environments present extreme conditions characterized by low barometric pressure and oxygen deficiency, which can disrupt brain functioning and cause edema formation. The objective of the present study is to investigate several biomolecule expressions and their role in the development of High Altitude Cerebral Edema in a rat model. Specifically, the study focuses on analyzing the changes in total arginase, nitric oxide, and lipid peroxidation (MDA) levels in the brain following acute hypobaric hypoxic exposure (7620 m, SO 2 =8.1 %, for 24 h) along with the histopathological assessment. The histological examination revealed increased TNF-α activity, and an elevated number of mast cells in the brain, mainly in the hippocampus and cerebral cortex. The research findings demonstrated that acute hypobaric hypoxic causes increased levels of apoptotic cells, shrinkage, and swelling of neurons, accompanied by the formation of protein aggregation in the brain parenchyma. Additionally, the level of nitric oxide and MDA was found to have increased (p<0.0001), however, the level of arginase decreased indicating active lipid peroxidation and redox imbalance in the brain. This study provides insights into the pathogenesis of HACE by evaluating some biomolecules that play a pivotal role in the inflammatory response and the redox landscape in the brain. The findings could have significant implications for understanding the neuronal dysfunction and the pathological mechanisms underlying HACE development., Competing Interests: Declaration of Competing Interest The authors declared no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Brain Muscle ARNT-Like Protein 1 (BMAL1) suppresses oxidative stress in brain injury during surgery. Epigallocatechin-3-gallate (EGCG), a monomer in green tea, has been identified as an antioxidant and a potential agonist for BMAL1. In this work, the mechanism by which BMAL1 is regulated was investigated, as well as the therapeutic effect of EGCG on surgically injured rats. The pathological environment after brain injury during surgery was simulated by excising the right frontal lobe of rats. Rats received an intraperitoneal injection of EGCG immediately after surgery. Neurological scores and cerebral edema were recorded after surgery. Fluoro-Jade C staining, TUNEL staining, western blot, and lipid peroxidation analyses were conducted 3 days later. Here we show that the endogenous BMAL1 level decreased after brain injury. Postoperative administration of EGCG up-regulated the content of BMAL1 around the cerebral cortex, reduced the oxidative stress level, reduced neuronal apoptosis and the number of degenerated neurons, alleviated cerebral edema, and improved neurological scores in rats. This suggests that BMAL1 is an effective target for treating surgical brain injury, as well as that EGCG may be a promising agent for alleviating postoperative brain injury., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

We have previously shown that phosphodiesterase 4 (PDE4) inhibition protects against neuronal injury in rats following middle cerebral artery occlusion/reperfusion (MCAO/R). However, the effects of PDE4 on brain edema and astrocyte swelling are unknown. In this study, we showed that inhibition of PDE4 by Roflumilast (Roflu) reduced brain edema and brain water content in rats subjected to MCAO/R. Roflu decreased the expression of aquaporin 4 (AQP4), while the levels of phosphorylated protein kinase B (Akt) and forkhead box O3a (FoxO3a) were increased. In addition, Roflu reduced cell volume and the expression of AQP4 in primary astrocytes undergoing oxygen and glucose deprivation/reoxygenation (OGD/R). Consistently, PDE4B knockdown showed similar effects as PDE4 inhibition; and PDE4B overexpression rescued the inhibitory role of PDE4B knockdown on AQP4 expression. We then found that the effects of Roflu on the expression of AQP4 and cell volume were blocked by the Akt inhibitor MK2206. Since neuroinflammation and astrocyte activation are the common events that are observed in stroke, we treated primary astrocytes with interleukin-1β (IL-1β). Astrocytes treated with IL-1β showed decreased AQP4 and phosphorylated Akt and FoxO3a. Roflu significantly reduced AQP4 expression, which was accompanied by increased phosphorylation of Akt and FoxO3a. Furthermore, overexpression of FoxO3a partly reversed the effect of Roflu on AQP4 expression. Our findings suggest that PDE4 inhibition limits ischemia-induced brain edema and astrocyte swelling via the Akt/FoxO3a/AQP4 pathway. PDE4 is a promising target for the intervention of brain edema after cerebral ischemia., (© 2024 Wiley Periodicals LLC.)

Objective: The glymphatic system serves as a perivascular pathway that aids in clearing liquid and solute waste from the brain, thereby enhancing neurological function. Disorders in glymphatic drainage contribute to the development of vasogenic edema following cerebral ischemia, although the molecular mechanisms involved remain poorly understood. This study aims to determine whether a deficiency in dystrophin 71 (DP71) leads to aquaporin-4 (AQP4) depolarization, contributing to glymphatic dysfunction in cerebral ischemia and resulting in brain edema., Methods: A mice model of middle cerebral artery occlusion and reperfusion was used. A fluorescence tracer was injected into the cortex and evaluated glymphatic clearance. To investigate the role of DP71 in maintaining AQP4 polarization, an adeno-associated virus with the astrocyte promoter was used to overexpress Dp71. The expression and distribution of DP71 and AQP4 were analyzed using immunoblotting, immunofluorescence, and co-immunoprecipitation techniques. The behavior ability of mice was evaluated by open field test. Open-access transcriptome sequencing data were used to analyze the functional changes of astrocytes after cerebral ischemia. MG132 was used to inhibit the ubiquitin-proteasome system. The ubiquitination of DP71 was detected by immunoblotting and co-immunoprecipitation., Results: During the vasogenic edema stage following cerebral ischemia, a decline in the efflux of interstitial fluid tracer was observed. DP71 and AQP4 were co-localized and interacted with each other in the perivascular astrocyte endfeet. After cerebral ischemia, there was a notable reduction in DP71 protein expression, accompanied by AQP4 depolarization and proliferation of reactive astrocytes. Increased DP71 expression restored glymphatic drainage and reduced brain edema. AQP4 depolarization, reactive astrocyte proliferation, and the behavior of mice were improved. After cerebral ischemia, DP71 was degraded by ubiquitination, and MG132 inhibited the decrease of DP71 protein level., Conclusion: AQP4 depolarization after cerebral ischemia leads to glymphatic clearance disorder and aggravates cerebral edema. DP71 plays a pivotal role in regulating AQP4 polarization and consequently influences glymphatic function. Changes in DP71 expression are associated with the ubiquitin-proteasome system. This study offers a novel perspective on the pathogenesis of brain edema following cerebral ischemia., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Subarachnoid hemorrhage (SAH) is characterized by the extravasation of blood into the subarachnoid space, in which erythrocyte lysis is the primary contributor to cell death and brain injuries. New evidence has indicated that meningeal lymphatic vessels (mLVs) are essential in guiding fluid and macromolecular waste from cerebrospinal fluid (CSF) into deep cervical lymph nodes (dCLNs). However, the role of mLVs in clearing erythrocytes after SAH has not been completely elucidated. Hence, we conducted a cross-species study. Autologous blood was injected into the subarachnoid space of rabbits and rats to induce SAH. Erythrocytes in the CSF were measured with/without deep cervical lymph vessels (dCLVs) ligation. Additionally, prior to inducing SAH, we administered rats with vascular endothelial growth factor C (VEGF-C), which is essential for meningeal lymphangiogenesis and maintaining integrity and survival of lymphatic vessels. The results showed that the blood clearance rate was significantly lower after dCLVs ligation in both the rat and rabbit models. DCLVs ligation aggravated neuroinflammation, neuronal damage, brain edema, and behavioral impairment after SAH. Conversely, the treatment of VEGF-C enhanced meningeal lymphatic drainage of erythrocytes and improved outcomes in SAH. In summary, our research highlights the indispensable role of the meningeal lymphatic pathway in the clearance of blood and mediating consequences after SAH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Intracerebral hemorrhage (ICH) is a significant public health matter that has no effective treatment. ICH-induced destruction of the blood-brain barrier (BBB) leads to neurological deterioration. Astrocytic sonic hedgehog (SHH) alleviates brain injury by maintaining the integrity of the BBB after ICH. Silent information regulator 1 (SIRT1) is neuroprotective in several central nervous system diseases via BBB regulation. It is also a possible influential factor of the SHH signaling pathway. Nevertheless, the role of SIRT1 on BBB and the underlying pathological process associated with the SHH signaling pathway after ICH remain unclear. We established an intracerebral hemorrhagic mouse model by collagenase injection. SRT1720 (a selective agonist of SIRT1) was used to evaluate the effect of SIRT1 on BBB integrity after ICH. SIRT1 expression was reduced in the mouse brain after ICH. SRT1720 attenuated neurobehavioral impairments and brain edema of ICH mouse. After ICH induction, SRT1720 improved BBB integrity and tight junction expressions in the mouse brain. The SHH signaling pathway-related factors smoothened and glioma-associated oncogene homolog-1 were increased with the intervention of SRT1720, while cyclopamine (a specific inhibitor of the SHH signaling pathway) reversed these effects. These findings suggest that SIRT1 protects from ICH by altering BBB permeability and tight junction expression levels. This process is associated with the SHH signaling pathway, suggesting that SIRT1 may be a potential therapeutic target for ICH., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Traumatic brain injury (TBI) is a significant cause of disability and mortality worldwide, and effective treatment options are currently limited. Monocyte locomotion inhibitor factor (MLIF), a small molecular pentapeptide, has demonstrated a protective effect against cerebral ischemia. This study aimed to investigate the protective effects of MLIF on TBI and explore its underlying mechanism of action. In animal experiments, we observed that administration of MLIF after TBI reduced brain water content and improved brain edema, suggesting a certain degree of protection against TBI. By utilizing network pharmacology methodologies, we employed target screening techniques to identify the potential targets of MLIF in the context of TBI. As a result, we successfully enriched ten signaling pathways that are closely associated with TBI. Furthermore, using molecular docking techniques, we identified AQP4 as one of the top ten central genes discovered in this study. Eventually, our study demonstrated that MLIF exhibits anti-apoptotic properties and suppresses the expression of AQP4 protein, thus playing a protective role in traumatic brain injury. This conclusion was supported by TUNEL staining and the evaluation of Bcl-2, Bax, and AQP4 protein levels. These discoveries enhance our comprehension of the mechanisms by which MLIF exerts its protective effects and highlight its potential as a promising therapeutic intervention for TBI treatment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Peritumoral brain edema (PTBE) has been widely reported with many brain tumors, especially with glioma. Since the blood-brain barrier (BBB) is essential for maintaining minimal permeability, any alteration in the interaction of BBB components, specifically in astrocytes and tight junctions (TJ), can result in disrupting the homeostasis of the BBB and making it severely leaky, which subsequently generates edema., Objective: This study aimed to evaluate the functional gliovascular unit of the BBB by examining changes in the expression of claudin (CLDN) genes and the expression of transient receptor potential (TRP) membrane channels, additionally to define the correlation between their expressions. The evaluation was conducted using in vitro spheroid swelling models and tumor samples from glioma patients with PTBE., Results: The results of the spheroid model showed that the genes TRPC3, TRPC4, TRPC5, and TRPV1 were upregulated in glioma cells either wild-type isocitrate dehydrogenase 1 (IDH1) or the IDH1 R132H mutant, with or without NaCl treatment. Furthermore, TRP genes appeared to adversely correlate with the up regulation of CLDN1, CLDN3, and CLDN5 genes. Besides, the upregulation of TRPC1 and TRPC4 in IDH1mt-R132H glioma cells. On the other hand, the correlation analysis revealed different correlations between different proteins in PTBE. CLDN1 exhibits a slight positive correlation with CLDN3. Similarly, TRPV1 displays a slight positive correlation with TRPC1. In contrast, TRPC4 shows a slight negative correlation with TRPC5. On the other hand, TRPC3 demonstrates a slight positive correlation with TRPC5, while the non-PTBE analysis highlights a moderate positive correlation between CLDN1 and TRPM4 while CLDN3 exhibits a moderate negative correlation with TRPC4. Additionally, CLDN5 demonstrates a slight negative correlation with TRPC4 but a moderate positive correlation with TRPC3. Furthermore, TRPC1 have a slight negative correlation with TRPV1, TRPC3 exhibiting a slight positive correlation with TRPC4, and TRPV1 showing a slight negative correlation with TRPC5., Conclusion: As a conclusion, the current study provided evidence of a slight negative correlation between TRPs and CLDN gene expression in PTBE patients and confirmatory results with some of the genes in cell model of edema., (© 2024 The Author(s). Cancer Medicine published by John Wiley & Sons Ltd.)

This study aimed to investigate the effects of G1-activated G protein-coupled estrogen receptor 1 (GPER1) on neurological impairments and neuroinflammation in traumatic brain injury (TBI) mice. The controlled cortical impingement (CCI) method was used to establish the TBI model. The mice were subjected to ovariectomy (OVX) for two weeks prior to modeling. GPER1 agonist G1 was administered by intracerebroventricular injection. Brain tissue water content was detected by wet/dry method, and blood-brain barrier damage was detected by Evans blue extravasation. The neurological impairments in mice were evaluated by open field test, Y-maze test, nest-building test, object location memory test and novel object recognition test. Ionized calcium-binding adapter molecule 1 (Iba1) staining was used to indicate the activation of microglia. Expression of M1/M2-type microglia markers and inflammatory factors were evaluated by ELISA and qRT-PCR. The G1 administration significantly reduced cerebral edema and Evans blue extravasation at injury ipsilateral cortex and basal ganglia in TBI mice. Activation of GPER1 by G1 improved the anxiety behavior and the cognitive dysfunction of mice induced by TBI. G1 administration significantly decreased Iba1-positive staining cells and the mRNA levels of CD86, macrophage cationic peptide 1 (Mcp-1), nitric oxide synthase 2 (Nos2), interleukin 1 beta (IL-1β), and macrophage inflammatory protein-2 (MIP-2), while increased the mRNA levels of interleukin 10 (IL-10), arginase1 (Arg-1) and CD206. Activation of GPER1 through G1 administration has the potential to ameliorate cognitive dysfunction induced by TBI in mice. It may also inhibit the activation of M1 microglia in cortical tissue resulting from TBI, while promoting the activation of M2 microglia and contributing to the regulation of inflammatory responses., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Ischemic lesion net water uptake (NWU) represents a quantitative imaging biomarker for cerebral edema in acute ischemic stroke. Data on NWU for distinct occlusion locations remain scarce, but might help to improve the prognostic value of NWU. In this retrospective multicenter cohort study, we compared NWU between patients with proximal large vessel occlusion (pLVO; ICA or proximal M1) and distal large vessel occlusion (dLVO; distal M1 or M2). NWU was quantified by densitometric measurements of the early ischemic region. Arterial collateral status was assessed using the Maas scale. Regression analysis was used to investigate the relationship between occlusion location, NWU and ischemic lesion growth. A total of 685 patients met inclusion criteria. Early ischemic lesion NWU was higher in patients with pLVO compared with dLVO (7.7% vs 3.9%, P  < .001). The relationship between occlusion location and NWU was partially mediated by arterial collateral status. NWU was associated with absolute ischemic lesion growth between admission and follow-up imaging ( β estimate, 5.50, 95% CI, 3.81-7.19, P  < .001). This study establishes a framework for the relationship between occlusion location, arterial collateral status, early ischemic lesion NWU and ischemic lesion growth. Future prognostic thresholds for NWU might be optimized by adjusting for the occlusion location., Competing Interests: Declaration of conflicting interestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Laurens WINKELMEIER reports no disclosure.Dr Jeremy J. HEIT reports consulting for Medtronic and MicroVention and Medical and Scientific Advisory Board membership for iSchemaView.Dr Gabriel BROOCKS reported receiving personal fees from Eppdata GmbH and compensation as a speaker from Balt outside the submitted work.Julia PRÜTER reports no disclosure.Dr Christian HEITKAMP reports no disclosure.Maximilian SCHELL reports no disclosure.Dr Gregory W. ALBERS reports equity and consulting for iSchemaView and consulting from Medtronic.Dr Maarten G. LANSBERG reports no disclosure.Dr Max WINTERMARK reports grants and funding from the NIH under the grant numbers (1U01 NS086872-01, 1U01 NS087748-01 and 1R01 NS104094).Dr André KEMMLING reports a research collaboration agreement with Siemens Healthcare (company involved in CT/MRI distribution).Dr Christian Paul STRACKE reports no disclosure.Dr Adrien GUENEGO reports no disclosure.Dr Daniel PAECH reports no disclosure.Dr Jens FIEHLER reports grants and personal fees from Acandis, Cerenovus, MicroVention, Medtronic, Stryker, Phenox and grants from Route 92 outside the submitted work.Dr Tobias D. FAIZY reports grants from the German Research Foundation (DFG) during the conduct of the study.

Background: High-altitude cerebral edema (HACE) is considered an end-stage acute mountain sickness (AMS) that typically occurs in people after rapid ascent to 2500 m or more. While hypoxia is a fundamental feature of the pathophysiological mechanism of HACE, emerging evidence suggests that inflammation serves as a key risk factor in the occurrence and development of this disease. However, little is known about the molecular mechanism underlying their crosstalk., Methods: A mouse HACE model was established by combination treatment with hypobaric hypoxia exposure and lipopolysaccharides (LPS) stimulation. Lactylated-proteomic analysis of microglia was performed to reveal the global profile of protein lactylation. Molecular modeling was applied to evaluate the 3-D modeling structures. A combination of experimental approaches, including western blotting, quantitative real-time reverse transcriptionpolymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA), confocal microscopy and RNA interference, were used to explore the underlying molecular mechanisms., Results: We found that hypoxia exposure increased the lactate concentration and lactylation in mouse HACE model. Moreover, hypoxia aggravated the microglial neuroinflammatory response in a lactate-dependent manner. Global profiling of protein lactylation has shown that a large quantity of lysine-lactylated proteins are induced by hypoxia and preferentially occur in protein complexes, such as the NuRD complex, ribosome biogenesis complex, spliceosome complex, and DNA replication complex. The molecular modeling data indicated that lactylation could affect the 3-D theoretical structure and increase the solvent accessible surface area of HDAC1, MTA1 and Gatad2b, the core members of the NuRD complex. Further analysis by knockdown or selectively inhibition indicated that the NuRD complex is involved in hypoxia-mediated aggravation of inflammation., Conclusions: These results revealed a comprehensive profile of protein lactylation in microglia and suggested that protein lysine lactylation plays an important role in the regulation of protein function and subsequently contributes to the neuroinflammatory response under hypoxic conditions., (© 2024. The Author(s).)

Although diabetes mellitus negatively affects post-ischaemic stroke injury and recovery, its impact on intracerebral haemorrhage (ICH) remains uncertain. This study aimed to investigate the effect of experimental diabetes (ED) on ICH-induced injury and neurological impairment. Sprague-Dawley rats were induced with ED 2 weeks before ICH induction. Animals were randomly assigned to four groups: 1)Healthy; 2)ICH; 3)ED; 4)ED-ICH. ICH and ED-ICH groups showed similar functional assessment. The ED-ICH group exhibited significantly lower haemorrhage volume compared with the ICH group, except at 1 mo. The oedema/ICH volume ratio and cistern displacement ratio were significantly higher in the ED-ICH group. Vascular markers revealed greater expression of α-SMA in the ED groups (ED and ED-ICH) compared with ICH. Conversely, the ICH groups (ED-ICH and ICH) exhibited higher levels of VEGF compared to the healthy and ED groups. An assessment of myelin tract integrity showed an increase in fractional anisotropy in the ED and ED-ICH groups compared with ICH. The ED group showed higher cryomyelin expression than the ED-ICH and ICH groups. Additionally, the ED groups (ED and ED-ICH) displayed higher expression of MOG and Olig-2 than ICH. As for inflammation, MCP-1 levels were significantly lower in the ED-ICH groups compared with the ICH group. Notably, ED did not aggravate the neurological outcome; however, it results in greater ICH-related brain oedema, greater brain structure displacement and lower haemorrhage volume. ED influences the cerebral vascularisation with an increase in vascular thickness, limits the inflammatory response and attenuates the deleterious effect of ICH on white matter integrity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare no competing financial interests., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Aquaporin-4 (AQP4) is the main water channel in brain and is enriched in perivascular astrocyte processes abutting brain microvessels. There is a rich literature on the role of AQP4 in experimental stroke. While its role in oedema formation following middle cerebral artery occlusion (MCAO) has been studied extensively, its specific impact on infarct volume remains unclear. This study investigated the effects of total and partial AQP4 deletion on infarct volume in mice subjected to distal medial cerebral artery (dMCAO) occlusion. Compared to MCAO, this model induces smaller infarcts confined to neocortex, and less oedema. We show that AQP4 deletion significantly reduced infarct volume as assessed 1 week after dMCAO, suggesting that the role of AQP4 in stroke goes beyond its effect on oedema formation and dissolution. The reduction in infarct volume was associated with increased astrocyte reactivity in the peri-infarct areas. No significant differences were observed in the number of microglia among the genotypes. These findings provide new insights in the role of AQP4 in ischaemic injury indicating that AQP4 affects both infarct volume and astrocyte reactivity in the peri-infarct zone. KEY POINTS: Aquaporin-4 (AQP4) is the main water channel in brain and is enriched in perivascular astrocyte processes abutting microvessels. A rich literature exists on the role of AQP4 in oedema formation following middle cerebral artery occlusion (MCAO). We investigated the effects of total and partial AQP4 deletion on infarct volume in mice subjected to distal medial cerebral artery occlusion (dMCAO), a model inducing smaller infarcts confined to neocortex and less oedema compared to MCAO. AQP4 deletion significantly reduced infarct volume 1 week after dMCAO, suggesting a broader role for AQP4 in stroke beyond oedema formation. The reduction in infarct volume was associated with increased astrocyte reactivity in the peri-infarct areas, while no significant differences were observed in the number of microglia among the genotypes. These findings provide new insights into the role of AQP4 in stroke, indicating that AQP4 affects both infarct volume and astrocyte reactivity in the peri-infarct zone., (© 2024 The Author(s). The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Objectives: Edaravone dexborneol is neuroprotective against ischemic stroke, with free radical-scavenging and anti-inflammatory effects, but its effects in hemorrhagic stroke remain unclear. We evaluated whether edaravone dexborneol has a neuroprotective effect in intracerebral hemorrhage, and its underlying mechanisms., Materials and Methods: Bioinformatics were used to predict the pathway of action of edaravone dexborneol. An intracerebral hemorrhage model was established using type IV collagenase in edaravone dexborneol, intracerebral hemorrhage, Sham, adeno-associated virus + edaravone dexborneol, and adeno-associated virus + intracerebral hemorrhage groups. The modified Neurological Severity Score was used to evaluate neurological function in rats. Brain water content was measured using the dry-wet weight method. Tumor necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and γ-aminobutyric acid levels were determined by enzyme-linked immunosorbent assay. The expression levels of neurofilament light chain and γ-aminobutyric acid transaminase were determined by western blot. Nissl staining was used to examine neuronal morphology. Cognitive behavior was evaluated using a small-animal treadmill., Results: Edaravone dexborneol alleviated neurological defects, improved cognitive function, and reduced cerebral edema, neuronal degeneration, and necrosis in rats with cerebral hemorrhage. The expression levels of neurofilament light chain, tumor necrosis factor-α, interleukin-1β, inducible nitric oxide synthase, and γ-aminobutyric acid were decreased, while γ-aminobutyric acid transaminase expression was up-regulated., Conclusions: Edaravone dexborneol regulates γ-aminobutyric acid content by acting on the γ-aminobutyric acid transaminase signaling pathway, thus alleviating oxidative stress, neuroinflammation, neuronal degeneration, and death caused by excitatory toxic injury of neurons after intracerebral hemorrhage., Competing Interests: Declaration of competing interest The authors have no potential conflicts of interest to disclose., (Copyright © 2024. Published by Elsevier Inc.)

Background: Selective water uptake by neurons and glial cells and subsequent brain tissue oedema are key pathophysiological processes of hypoxic-ischemic encephalopathy (HIE) after cardiac arrest (CA). Although brain computed tomography (CT) is widely used to assess the severity of HIE, changes of brain radiodensity over time have not been investigated. These could be used to quantify regional brain net water uptake (NWU), a potential prognostic biomarker., Methods: We conducted an observational prognostic accuracy study including a derivation (single center cardiac arrest registry) and a validation (international multicenter TTM2 trial) cohort. Early (<6 h) and follow-up (>24 h) head CTs of CA patients were used to determine regional NWU for grey and white matter regions after co-registration with a brain atlas. Neurological outcome was dichotomized as good versus poor using the Cerebral Performance Category Scale (CPC) in the derivation cohort and Modified Rankin Scale (mRS) in the validation cohort., Results: We included 115 patients (81 derivation, 34 validation) with out-of-hospital (OHCA) and in-hospital cardiac arrest (IHCA). Regional brain water content remained unchanged in patients with good outcome. In patients with poor neurological outcome, we found considerable regional water uptake with the strongest effect in the basal ganglia. NWU >8% in the putamen and caudate nucleus predicted poor outcome with 100% specificity (95%-CI: 86-100%) and 43% (moderate) sensitivity (95%-CI: 31-56%)., Conclusion: This pilot study indicates that NWU derived from serial head CTs is a promising novel biomarker for outcome prediction after CA. NWU >8% in basal ganglia grey matter regions predicted poor outcome while absence of NWU indicated good outcome. NWU and follow-up CTs should be investigated in larger, prospective trials with standardized CT acquisition protocols., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Traumatic brain injury (TBI), as a major public health problem, is characterized by high incidence rate, disability rate, and mortality rate. Neuroinflammation plays a crucial role in the pathogenesis of TBI. Triggering receptor expressed on myeloid cells-1 (TREM-1) is recognized as an amplifier of the inflammation in diseases of the central nervous system (CNS). However, the function of TREM-1 remains unclear post-TBI. This study aimed to investigate the function of TREM-1 in neuroinflammation induced by TBI., Methods: Brain water content (BWC), modified neurological severity score (mNSS), and Morris Water Maze (MWM) were measured to evaluate the effect of TREM-1 inhibition on nervous system function and outcome after TBI. TREM-1 expression in vivo was evaluated by Western blotting. The cellular localization of TREM-1 in the damaged region was observed via immunofluorescence staining. We also conducted Western blotting to examine expression of SYK, p-SYK and other downstream proteins., Results: We found that inhibition of TREM-1 reduced brain edema, decreased mNSS and improved neurobehavioral outcomes after TBI. It was further determined that TREM-1 was expressed on microglia and modulated subtype transition of microglia. Inhibition of TREM-1 alleviated neuroinflammation, which was associated with SYK/p38MAPK signaling pathway., Conclusions: These findings suggest that TREM-1 can be a potential clinical therapeutic target for alleviating neuroinflammation after TBI., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Secondary brain injury after intracerebral hemorrhage (ICH) is the main cause of poor prognosis in ICH patients, but the underlying mechanisms remain less known. The involvement of Piezo1 in brain injury after ICH was studied in a mouse model of ICH. ICH was established by injecting autologous arterial blood into the basal ganglia in mice. After vehicle, Piezo1 blocker, GsMTx4, Piezo1 activator, Yoda-1, or together with mannitol (tail vein injection) was injected into the left lateral ventricle of mouse brain, Piezo1 level and the roles of Piezo1 in neuronal injury, brain edema, and neurological dysfunctions after ICH were determined by the various indicated methods. Piezo1 protein level in neurons was significantly upregulated 24 h after ICH in vivo (human and mice). Piezo1 protein level was also dramatically upregulated in HT22 cells (a murine neuron cell line) cultured in vitro 24 h after hemin treatment as an in vitro ICH model. GsMTx4 treatment or together with mannitol significantly downregulated Piezo1 and AQP4 levels, markedly increased Bcl2 level, maintained more neurons alive, considerably restored brain blood flow, remarkably relieved brain edema, substantially decreased serum IL-6 level, and almost fully reversed the neurological dysfunctions at ICH 24 h group mice. In contrast, Yoda-1 treatment achieved the opposite effects. In conclusion, Piezo1 plays a crucial role in the pathogenesis of brain injury after ICH and may be a target for clinical treatment of ICH., Competing Interests: Declaration of competing interest The author declared no potential conflicts of interest with respect to the research, authorship, and publication of this article., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Aquaporins (AQPs), particularly AQP4, play a crucial role in regulating fluid dynamics in the brain, impacting the development and resolution of edema following traumatic brain injury (TBI). This review examines the alterations in AQP expression and localization post-injury, exploring their effects on brain edema and overall injury outcomes. We discuss the underlying molecular mechanisms regulating AQP expression, highlighting potential therapeutic strategies to modulate AQP function. These insights provide a comprehensive understanding of AQPs in TBI and suggest novel approaches for improving clinical outcomes through targeted interventions.

Oedema occurs when higher than normal amounts of solutes and water accumulate in tissues. In brain parenchymal tissue, vasogenic oedema arises from changes in blood-brain barrier permeability, e.g. in peritumoral oedema. Cytotoxic oedema arises from excess accumulation of solutes within cells, e.g. ischaemic oedema following stroke. This type of oedema is initiated when blood flow in the affected core region falls sufficiently to deprive brain cells of the ATP needed to maintain ion gradients. As a consequence, there is: depolarization of neurons; neural uptake of Na + and Cl - and loss of K + ; neuronal swelling; astrocytic uptake of Na + , K + and anions; swelling of astrocytes; and reduction in ISF volume by fluid uptake into neurons and astrocytes. There is increased parenchymal solute content due to metabolic osmolyte production and solute influx from CSF and blood. The greatly increased [K + ] isf triggers spreading depolarizations into the surrounding penumbra increasing metabolic load leading to increased size of the ischaemic core. Water enters the parenchyma primarily from blood, some passing into astrocyte endfeet via AQP4. In the medium term, e.g. after three hours, NaCl permeability and swelling rate increase with partial opening of tight junctions between blood-brain barrier endothelial cells and opening of SUR1-TPRM4 channels. Swelling is then driven by a Donnan-like effect. Longer term, there is gross failure of the blood-brain barrier. Oedema resolution is slower than its formation. Fluids without colloid, e.g. infused mock CSF, can be reabsorbed across the blood-brain barrier by a Starling-like mechanism whereas infused serum with its colloids must be removed by even slower extravascular means. Large scale oedema can increase intracranial pressure (ICP) sufficiently to cause fatal brain herniation. The potentially lethal increase in ICP can be avoided by craniectomy or by aspiration of the osmotically active infarcted region. However, the only satisfactory treatment resulting in retention of function is restoration of blood flow, providing this can be achieved relatively quickly. One important objective of current research is to find treatments that increase the time during which reperfusion is successful. Questions still to be resolved are discussed., (© 2024. The Author(s).)

Background: Perihematomal edema (PHE) after post-intracerebral hemorrhage (ICH) has complex pathophysiological mechanisms that are poorly understood. The complicated immune response in the post-ICH brain constitutes a crucial component of PHE pathophysiology. In this study, we aimed to characterize the transcriptional profiles of immune cell populations in human PHE tissue and explore the microscopic differences between different types of immune cells., Methods: 9 patients with basal ganglia intracerebral hemorrhage (hematoma volume 50-100 ml) were enrolled in this study. A multi-stage profile was developed, comprising Group1 (n = 3, 0-6 h post-ICH, G1), Group2 (n = 3, 6-24 h post-ICH, G2), and Group3 (n = 3, 24-48 h post-ICH, G3). A minimal quantity of edematous tissue surrounding the hematoma was preserved during hematoma evacuation. Single cell RNA sequencing (scRNA-seq) was used to map immune cell populations within comprehensively resected PHE samples collected from patients at different stages after ICH., Results: We established, for the first time, a comprehensive landscape of diverse immune cell populations in human PHE tissue at a single-cell level. Our study identified 12 microglia subsets and 5 neutrophil subsets in human PHE tissue. What's more, we discovered that the secreted phosphoprotein-1 (SPP1) pathway served as the basis for self-communication between microglia subclusters during the progression of PHE. Additionally, we traced the trajectory branches of different neutrophil subtypes. Finally, we also demonstrated that microglia-produced osteopontin (OPN) could regulate the immune environment in PHE tissue by interacting with CD44-positive cells., Conclusions: As a result of our research, we have gained valuable insight into the immune-microenvironment within PHE tissue, which could potentially be used to develop novel treatment modalities for ICH., (© 2024. The Author(s).)

High-altitude cerebral edema (HACE) is a severe neurological condition that can occur at high altitudes. It is characterized by the accumulation of fluid in the brain, leading to a range of symptoms, including severe headache, confusion, loss of coordination, and even coma and death. Exosomes play a crucial role in intercellular communication, and their contents have been found to change in various diseases. This study analyzed the metabolomic characteristics of blood exosomes from HACE patients compared to those from healthy controls (HCs) with the aim of identifying specific metabolites or metabolic pathways associated with the development of HACE conditions. A total of 21 HACE patients and 21 healthy controls were recruited for this study. Comprehensive metabolomic profiling of the serum exosome samples was conducted using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC‒MS/MS). Additionally, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed to identify the metabolic pathways affected in HACE patients. Twenty-six metabolites, including ( +)-camphoric acid, choline, adenosine, adenosine 5'-monophosphate, deoxyguanosine 5'-monophosphate, guanosine, and hypoxanthine-9-β-D-arabinofuranoside, among others, exhibited significant changes in expression in HACE patients compared to HCs. Additionally, these differentially abundant metabolites were confirmed to be potential biomarkers for HACE. KEGG pathway enrichment analysis revealed several pathways that significantly affect energy metabolism regulation (such as purine metabolism, thermogenesis, and nucleotide metabolism), estrogen-related pathways (the estrogen signaling pathway, GnRH signaling pathway, and GnRH pathway), cyclic nucleotide signaling pathways (the cGMP-PKG signaling pathway and cAMP signaling pathway), and hormone synthesis and secretion pathways (renin secretion, parathyroid hormone synthesis, secretion and action, and aldosterone synthesis and secretion). In patients with HACE, adenosine, guanosine, and hypoxanthine-9-β-D-arabinofuranoside were negatively correlated with height. Deoxyguanosine 5'-monophosphate is negatively correlated with weight and BMI. Additionally, LPE (18:2/0:0) and pregnanetriol were positively correlated with age. This study identified potential biomarkers for HACE and provided valuable insights into the underlying metabolic mechanisms of this disease. These findings may lead to potential targets for early diagnosis and therapeutic intervention in HACE patients., (© 2024. The Author(s).)

Background: Cardiopulmonary bypass (CPB) results in brain injury, which is primarily caused by inflammation. Ac2-26 protects against ischemic or hemorrhage brain injury. The present study was to explore the effect and mechanism of Ac2-26 on brain injury in CPB rats., Methods: Forty-eight rats were randomized into sham, CPB, Ac, Ac/AKT1, Ac/GSK3βi and Ac/AKT1/GSK3βa groups. Rats in sham group only received anesthesia and in the other groups received standard CPB surgery. Rats in the sham and CPB groups received saline, and rats in the Ac, Ac/AKT1, Ac/GSK3βi and Ac/AKT1/GSK3βa groups received Ac2-26 immediately after CPB. Rats in the Ac/AKT1, Ac/GSK3βi and Ac/AKT1/GSK3βa groups were injected with shRNA, inhibitor and agonist of GSK3β respectively. The neurological function score, brain edema and histological score were evaluated. The neuronal survival and hippocampal pyroptosis were assessed. The cytokines, activity of NF-κB, S100 calcium-binding protein β(S100β) and neuron-specific enolase (NSE), and oxidative were tested. The NLRP3, cleaved-caspase-1 and cleaved-gadermin D (GSDMD) in the brain were also detected., Results: Compared to the sham group, all indicators were aggravated in rats that underwent CPB. Compared to the CPB group, Ac2-26 significantly improved neurological scores and brain edema and ameliorated pathological injury. Ac2-26 reduced the local and systemic inflammation, oxidative stress response and promoted neuronal survival. Ac2-26 reduced hippocampal pyroptosis and decreased pyroptotic proteins in brain tissue. The protection of Ac2-26 was notably lessened by shRNA and inhibitor of GSK3β. The agonist of GSK3β recovered the protection of Ac2-26 in presence of shRNA., Conclusions: Ac2-26 significantly improved neurological function, reduced brain injury via regulating inflammation, oxidative stress response and pyroptosis after CPB. The protective effect of Ac2-26 primarily depended on AKT1/ GSK3β pathway., (© 2024. The Author(s).)

Background: Most subarachnoid hemorrhage (SAH) patients have no obvious hematoma lesions but exhibit blood-brain barrier dysfunction and vasogenic brain edema. However, there is a few days between blood‒brain barrier dysfunction and vasogenic brain edema. The present study sought to investigate whether this phenomenon is caused by endothelial injury induced by the acute astrocytic barrier, also known as the glial limitans., Methods: Bioinformatics analyses of human endothelial cells and astrocytes under hypoxia were performed based on the GEO database. Wild-type, EGLN3 and PKM2 conditional knock-in mice were used to confirm glial limitan formation after SAH. Then, the effect of endothelial EGLN3-PKM2 signaling on temporal and spatial changes in glial limitans was evaluated in both in vivo and in vitro models of SAH., Results: The data indicate that in the acute phase after SAH, astrocytes can form a temporary protective barrier, the glia limitans, around blood vessels that helps maintain barrier function and improve neurological prognosis. Molecular docking studies have shown that endothelial cells and astrocytes can promote glial limitans-based protection against early brain injury through EGLN3/PKM2 signaling and further activation of the PKC/ERK/MAPK signaling pathway in astrocytes after SAH., Conclusion: Improving the ability to maintain glial limitans may be a new therapeutic strategy for improving the prognosis of SAH patients., (© 2024. The Author(s).)

Hyperglycemia has been linked to worsening outcomes after subarachnoid hemorrhage (SAH). Nevertheless, the mechanisms involved in the pathogenesis of SAH have been scarcely evaluated so far. The role of hyperglycemia was assessed in an experimental model of SAH by T 2 weighted, dynamic contrast-enhanced magnetic resonance imaging (T 2 W and DCE-MRI), [ 18 F]BR-351 PET imaging and immunohistochemistry. Measures included the volume of bleeding, the extent of cerebral infarction and brain edema, blood brain barrier disruption (BBBd), neutrophil infiltration and matrix metalloprotease (MMP) activation. The neurofunctional outcome, neurodegeneration and myelinization were also investigated. The induction of hyperglycemia increased mortality, the size of the ischemic lesion, brain edema, neurodegeneration and worsened neurological outcome during the first 3 days after SAH in rats. In addition, these results show for the first time the exacerbating effect of hyperglycemia on in vivo MMP activation, Intercellular Adhesion Molecule 1 (ICAM-1) expression and neutrophil infiltration together with increased BBBd, bleeding volume and fibrinogen accumulation at days 1 and 3 after SAH. Notably, these data provide valuable insight into the detrimental effect of hyperglycemia on early BBB damage mediated by neutrophil infiltration and MMP activation that could explain the worse prognosis in SAH., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Cerebral ischemia/reperfusion (I/R) injury increases blood-brain barrier (BBB) permeability, leading to hemorrhagic transformation and brain edema. Normobaric oxygen (NBO) is a routine clinical treatment strategy for this condition. However, its neuroprotective effects remain controversial. This study investigated the effect of different NBO concentrations on I/R injury and explores the involvement of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in the underlying mechanism. A mouse middle cerebral artery occlusion (MCAO) model, and an oxygen and glucose deprivation (OGD) model featuring mouse brain microvascular endothelial cells (ECs) called bEnd.3, were used to investigate the effect of NBO on I/R injury. A reactive oxygen species (ROS) inducer and Nrf2-knockdown by RNA were used to explore whether the Nrf2 pathway mediates the effect of NBO on cerebrovascular ECs. In the early stage of MCAO, 40% O 2 NBO exposure significantly improved blood perfusion in the ischemic area and effectively relieved BBB permeability, cerebral edema, cerebral injury, and neurological function after MCAO. In the OGD model, 40% O 2 NBO exposure significantly reduced apoptosis, inhibited ROS generation, reduced ER stress, upregulated the expression of tight junction proteins, and stabilized the permeability of ECs. Blocking the Nrf2 pathway nullified the protective effect of 40% O 2 NBO on ECs after OGD. Finally, our study confirmed that low concentrations of NBO have a neuroprotective effect on I/R by activating the Nrf2 pathway in ECs., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Intracerebral hemorrhage (ICH) is a devastating neurological disease causing severe sensorimotor dysfunction and cognitive decline, yet there is no effective treatment strategy to alleviate outcomes of these patients. The Mas axis-mediated neuroprotection is involved in the pathology of various neurological diseases, however, the role of the Mas receptor in the setting of ICH remains to be elucidated., Methods: C57BL/6 mice were used to establish the ICH model by injection of collagenase into mice striatum. The Mas receptor agonist AVE0991 was administered intranasally (0.9 mg/kg) after ICH. Using a combination of behavioral tests, Western blots, immunofluorescence staining, hematoma volume, brain edema, quantitative-PCR, TUNEL staining, Fluoro-Jade C staining, Nissl staining, and pharmacological methods, we examined the impact of intranasal application of AVE0991 on hematoma absorption and neurological outcomes following ICH and investigated the underlying mechanism., Results: Mas receptor was found to be significantly expressed in activated microglia/macrophages, and the peak expression of Mas receptor in microglia/macrophages was observed at approximately 3-5 days, followed by a subsequent decline. Activation of Mas by AVE0991 post-treatment promoted hematoma absorption, reduced brain edema, and improved both short- and long-term neurological functions in ICH mice. Moreover, AVE0991 treatment effectively attenuated neuronal apoptosis, inhibited neutrophil infiltration, and reduced the release of inflammatory cytokines in perihematomal areas after ICH. Mechanistically, AVE0991 post-treatment significantly promoted the transformation of microglia/macrophages towards an anti-inflammatory, phagocytic, and reparative phenotype, and this functional phenotypic transition of microglia/macrophages by Mas activation was abolished by both Mas inhibitor A779 and Nrf2 inhibitor ML385. Furthermore, hematoma clearance and neuroprotective effects of AVE0991 treatment were reversed after microglia depletion in ICH., Conclusions: Mas activation can promote hematoma absorption, ameliorate neurological deficits, alleviate neuron apoptosis, reduced neuroinflammation, and regulate the function and phenotype of microglia/macrophages via Akt/Nrf2 signaling pathway after ICH. Thus, intranasal application of Mas agonist ACE0991 may provide promising strategy for clinical treatment of ICH patients., (© 2024. The Author(s).)

Background and Purpose: It has been reported activation of NLRP3 inflammasome after intracerebral hemorrhage (ICH) ictus exacerbates neuroinflammation and brain injury. We hypothesized that inhibition of NLRP3 by OLT1177 (dapansutrile), a novel NLRP3 inflammasome inhibitor, could reduce brain edema and attenuate brain injury in experimental ICH., Methods: ICH was induced by injection of autologous blood into basal ganglia in mice models. Sixty-three C57Bl/6 male mice were randomly grouped into the sham, vehicle, OLT1177 (Dapansutrile, 200 mg/kg intraperitoneally) and treated for consecutive three days, starting from 1 h after ICH surgery. Behavioral test, brain edema, brain water content, blood-brain barrier integrity and vascular permeability, cell apoptosis, and NLRP3 and its downstream protein levels were measured., Results: OLT1177 significantly reduced cerebral edema after ICH and contributed to the attenuation of neurological deficits. OLT1177 could preserve blood-brain barrier integrity and lessen vascular leakage. In addition, OLT1177 preserved microglia morphological shift and significantly inhibited the activation of caspase-1 and release of IL-1β. We also found that OLT1177 can protect against neuronal loss in the affected hemisphere., Conclusions: OLT1177 (dapansutrile) could significantly attenuate the brain edema after ICH and effectively alleviate the neurological deficit. This result suggests that the novel NLRP3 inhibitor, OLT1177, might serve as a promising candidate for the treatment of ICH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Intracerebral hemorrhage (ICH) comprises primary and secondary injuries, the latter of which induces increased inflammation and apoptosis and is more severe. Activating transcription factor 6 (ATF6) is a type-II transmembrane protein in the endoplasmic reticulum (ER). ATF6 target genes could improve ER homeostasis, which contributes to cryoprotection. Hence, we predict that ATF6 will have a protective effect on brain tissue after ICH., Method: The ICH rat model was generated through autologous blood injection into the right basal ganglia, the expression of ATF6 after ICH was determined by WB and IF. The expression of ATF6 was effectively controlled by means of intervention, and a series of measures was used to detect cell death, neuroinflammation, brain edema, blood-brain barrier and other indicators after ICH. Finally, the effects on long-term neural function of rats were measured by behavioral means., Result: ATF6 was significantly increased in the ICH-induced brain tissues. Further, ATF6 was found to modulate the expression of cystathionine γ-lyase (CTH) after ICH. Upregulation of ATF6 attenuated neuronal apoptosis and inflammation in ICH rats, along with mitigation of ICH-induced brain edema, blood-brain barrier deterioration, and cognitive behavior defects. Conversely, ATF6 genetic knockdown induced effects counter to those aforementioned., Conclusions: This study thereby emphasizes the crucial role of ATF6 in secondary brain injury in response to ICH, indicating that ATF6 upregulation may potentially ameliorate ICH-induced secondary brain injury. Consequently, ATF6 could serve as a promising therapeutic target to alleviate clinical ICH-induced secondary brain injuries.

Brain edema is considered as a common feature associated with hepatic encephalopathy (HE). However, its central role as cause or consequence of HE and its implication in the development of the neurological alterations linked to HE are still under debate. It is now well accepted that type A and type C HE are biologically and clinically different, leading to different manifestations of brain edema. As a result, the findings on brain edema/swelling in type C HE are variable and sometimes controversial. In the light of the changing natural history of liver disease, better description of the clinical trajectory of cirrhosis and understanding of molecular mechanisms of HE, and the role of brain edema as a central component in the pathogenesis of HE is revisited in the current review. Furthermore, this review highlights the main techniques to measure brain edema and their advantages/disadvantages together with an in-depth description of the main ex-vivo/in-vivo findings using cell cultures, animal models and humans with HE. These findings are instrumental in elucidating the role of brain edema in HE and also in designing new multimodal studies by performing in-vivo combined with ex-vivo experiments for a better characterization of brain edema longitudinally and of its role in HE, especially in type C HE where water content changes are small., (© 2023. The Author(s).)

Cerebral ischemic stroke is a cerebrovascular disease, which is related to DNA damage. Many researches have shown that Ku70 is a key regulator for DNA damage. Here, we aimed to explore Ku70 roles in cerebral ischemic stroke and its potential molecular mechanism. In our study, neural stem cells (NSCs) were induced by oxygen-glucose deprivation/reoxygenation (OGD/R) for constructing cerebral ischemic stroke cell model. CCK8 assay, Brdu/GFP staining, flow cytometry and TUNEL staining were performed to examine cell proliferation, cell cycle and apoptosis, respectively. Relative mRNA and protein levels were detected by quantitative real-time PCR and western blot analysis, respectively. Ku70 positive cells were examined by immunofluorescence staining. Comet assay was employed to determine DNA damage. Animal experiments were performed to assess the effect of transplanting NSCs and Ku70-overexpressed NSCs on neurological deficits, infarct volume, brain edema and blood‒brain barrier (BBB) integrity in middle cerebral artery occlusion (MCAO) model. Our data found that Ku70 expression was decreased in NSCs after OGD/R. Overexpression of Ku70 reduced DNA damage and apoptosis of OGD/R-induced NSCs. Knockdown of Ku70 promoted the activity of ATM/p53. Moreover, KU60019 (ATM-specific inhibitor) reversed the promoting effects of Ku70 silencing on DNA damage and apoptosis in OGD/R-induced NSCs. In animal experiments, transplantation of NSCs-overexpressed Ku70 enhanced cell survival, improved motor function, reduced infarct volume, relieved brain edema and alleviated BBB dysfunction in MCAO mice models. In conclusion, Ku70 overexpression repressed the DNA damage and apoptosis in OGD/R-induced NSCs by regulating ATM/p53 pathway, and transplantation of NSCs-overexpressed Ku70 played neuroprotective effects in MCAO mice models., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Cerebral vasogenic edema, a severe complication of ischemic stroke, aggravates neurological deficits. However, therapeutics to reduce cerebral edema still represent a significant unmet medical need. Brain microvascular endothelial cells (BMECs), vital for maintaining the blood-brain barrier (BBB), represent the first defense barrier for vasogenic edema. Here, we analyzed the proteomic profiles of the cultured mouse BMECs during oxygen-glucose deprivation and reperfusion (OGD/R). Besides the extensively altered cytoskeletal proteins, ephrin type-A receptor 4 (EphA4) expressions and its activated phosphorylated form p-EphA4 were significantly increased. Blocking EphA4 using EphA4-Fc, a specific and well-tolerated inhibitor shown in our ongoing human phase I trial, effectively reduced OGD/R-induced BMECs contraction and tight junction damage. EphA4-Fc did not protect OGD/R-induced neuronal and astrocytic death. However, administration of EphA4-Fc, before or after the onset of transient middle cerebral artery occlusion (tMCAO), reduced brain edema by about 50%, leading to improved neurological function recovery. The BBB permeability test also confirmed that cerebral BBB integrity was well maintained in tMCAO brains treated with EphA4-Fc. Therefore, EphA4 was critical in signaling BMECs-mediated BBB breakdown and vasogenic edema during cerebral ischemia. EphA4-Fc is promising for the treatment of clinical post-stroke edema., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: CD44 is a major cell surface receptor involved in cell adhesion and migration. The overexpression of CD44 is a poor prognostic factor in many neoplasms, including meningiomas. The aim of this study was to investigate the association between CD44 gene expression and clinical signatures of primary meningiomas., Methods: CD44 gene expression was quantitatively evaluated by snap freezing tumor tissues obtained from 106 patients with primary meningioma. The relationships between CD44 expression and clinical signatures of meningiomas, including histological malignancy, tumor volume, and peritumoral brain edema (PTBE), were analyzed. PTBE was assessed using the Steinhoff classification (SC) system (from SC 0 to SC III)., Results: CD44 gene expression in WHO grade 2 and 3 meningiomas was significantly higher than that in grade 1 meningiomas. In addition, CD44 expression increased with the severity of PTBE. Particularly, among the grade 1 meningiomas or small-sized tumors (maximum tumor diameter < 43 mm), CD44 expression in tumors with severe PTBE (SC II or III) was significantly higher than that in tumors without or with mild PTBE (SC 0 or I). Multivariate logistic regression analysis also revealed that overexpression of CD44 was an independent significant factor of severe PTBE development in primary meningiomas., Conclusions: In addition to tumor cell aggressiveness, CD44 expression promotes the development of PTBE in meningioma. Since PTBE is a strong factor of tumor-related epilepsy or cognitive dysfunction in patients with meningioma, CD44 is thus a potential therapeutic target in meningioma with PTBE.

Acute cerebral ischemia triggers a profound inflammatory response. While macrophages polarized to an M2-like phenotype clear debris and facilitate tissue repair, aberrant or prolonged macrophage activation is counterproductive to recovery. The inhibitory immune checkpoint Programmed Cell Death Protein 1 (PD-1) is upregulated on macrophage precursors (monocytes) in the blood after acute cerebrovascular injury. To investigate the therapeutic potential of PD-1 activation, we immunophenotyped circulating monocytes from patients and found that PD-1 expression was upregulated in the acute period after stroke. Murine studies using a temporary middle cerebral artery (MCA) occlusion (MCAO) model showed that intraperitoneal administration of soluble Programmed Death Ligand-1 (sPD-L1) significantly decreased brain edema and improved overall survival. Mice receiving sPD-L1 also had higher performance scores short-term, and more closely resembled sham animals on assessments of long-term functional recovery. These clinical and radiographic benefits were abrogated in global and myeloid-specific PD-1 knockout animals, confirming PD-1+ monocytes as the therapeutic target of sPD-L1. Single-cell RNA sequencing revealed that treatment skewed monocyte maturation to a non-classical Ly6C lo , CD43 hi , PD-L1+ phenotype. These data support peripheral activation of PD-1 on inflammatory monocytes as a therapeutic strategy to treat neuroinflammation after acute ischemic stroke., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: HB has received research funding from the National Institutes of Health, Khatib Foundation, NICO Myriad Corporation, and philanthropy. He is the Chairman of the Medical Advisory Board for Insightec, which is developing focused ultrasound treatments for brain tumors. This arrangement has been reviewed and approved by Johns Hopkins University in accordance with its conflict-of-interest policies. He has consultation agreements with Accelerating Combination Therapies, Insightec, Candel Therapeutics, Inc., Catalio Nexus Fund II, LLC, LikeMinds, Inc*, Galen Robotics, Inc.*, CraniUS*, and Nurami Medical* (Includes equity or options). ML has received research funding from Arbor, Bristol Myers Squibb, Accuray, Biohaven, and Urogen. He is a consultant for VBI, InCephalo Therapeutics, Merck, Pyramid Bio, Insightec, Biohaven. Sanianoia, Novocure, Noxxon, Hemispherian, InCando, Century Therapeutics, CraniUs, MediFlix, and XSense. He is a shareholder in Egret Therapeutics. He is an inventor on patents for focused radiation + checkpoint inhibitors, local chemotherapy + checkpoint inhibitors, and checkpoints and Neuro-inflammation. He is a non-research consultant for Stryker and on the DSMB for Cellularity. RJT is an inventor on patents for immune checkpoints and neuroinflammation. CMJ has received research support from Biohaven, InCephalo, the Goldhirsh-Yellin Foundation, the Brain Aneurysm Foundation, and philanthropy. He is an inventor on patents for immune checkpoints and neuroinflammation. He is the co-founder and owns equity interest in Egret Therapeutics. This arrangement has been reviewed and approved by Johns Hopkins University in accordance with its conflict-of-interest policies., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Cerebral edema is one of the deadliest complications of ischemic stroke for which there is currently no pharmaceutical treatment. Aquaporin-4 (AQP4), a water-channel polarized at the astrocyte endfoot, is known to be highly implicated in cerebral edema. We previously showed in randomized studies that (S)-roscovitine, a cyclin-dependent kinase inhibitor, reduced cerebral edema 48 h after induction of focal transient ischemia, but its mechanisms of action were unclear. In our recent blind randomized study, we confirmed that (S)-roscovitine was able to reduce cerebral edema by 65% at 24 h post-stroke (t test, p = .006). Immunofluorescence analysis of AQP4 distribution in astrocytes revealed that (S)-roscovitine decreased the non-perivascular pool of AQP4 by 53% and drastically increased AQP4 clusters in astrocyte perivascular end-feet (671%, t test p = .005) compared to vehicle. Non-perivascular and clustered AQP4 compartments were negatively correlated (R = -0.78; p < .0001), suggesting a communicating vessels effect between the two compartments. α1-syntrophin, AQP4 anchoring protein, was colocalized with AQP4 in astrocyte endfeet, and this colocalization was maintained in ischemic area as observed on confocal microscopy. Moreover, (S)-roscovitine increased AQP4/α1-syntrophin interaction (40%, MW p = .0083) as quantified by proximity ligation assay. The quantified interaction was negatively correlated with brain edema in both treated and placebo groups (R = -.57; p = .0074). We showed for the first time, that a kinase inhibitor modulated AQP4/α1-syntrophin interaction, and was implicated in the reduction of cerebral edema. These findings suggest that (S)-roscovitine may hold promise as a potential treatment for cerebral edema in ischemic stroke and as modulator of AQP4 function in other neurological diseases., (© 2023 The Authors. GLIA published by Wiley Periodicals LLC.)