The AMPAR antagonist perampanel protects the neurovascular unit against traumatic injury via regulating Sirt3

Efficacy of perampanel by etiology in Japanese patients with epilepsy-subpopulation analysis of a prospective post-marketing observational study

OBJECTIVE

To examine the efficacy and safety of perampanel (PER) in patients with post-stroke epilepsy (PSE), brain tumor-related epilepsy (BTRE), and post-traumatic epilepsy (PTE) using Japanese real-world data.

METHODS

The prospective post-marketing observational study included patients with focal seizures with or without focal to bilateral tonic-clonic seizures who received PER combination therapy. The observation period was 24 or 52 weeks after the initial PER administration. The safety and efficacy analysis included 3716 and 3272 patients, respectively. This post hoc analysis examined responder rate (50% reduction in seizure frequency), seizure-free rate (proportion of patients who achieved seizure-free), and safety in patients included in the post-marketing study who had PSE, BTRE, and PTE in the 4 weeks prior to the last observation.

RESULTS

Overall, 402, 272, and 186 patients were included in the PSE, BTRE, and PTE subpopulations, and 2867 controls in the "Other" population (etiologies other than PSE, BTRE, or PTE). Mean modal dose (the most frequently administered dose) values at 52 weeks were 3.38, 3.36, 3.64, and 4.04 mg/day for PSE, BTRE, PTE, and "Other," respectively; PER retention rates were 56.2%, 54.0%, 52.6%, and 59.7%, respectively. Responder rates (% [95% confidence interval]) were 82% (76.3%-86.5%), 78% (70.8%-83.7%), 67% (56.8%-75.6%), and 50% (47.9%-52.7%) for PSE, BTRE, PTE, and "Other," respectively, and seizure-free rates were 71% (64.5%-76.5%), 62% (54.1%-69.0%), 50% (40.6%-60.4%), and 28% (25.8%-30.1%), respectively. Adverse drug reactions tended to occur less frequently in the PSE (14.7%), BTRE (16.5%), and PTE (16.7%) subpopulations than in the "Other" population (26.3%).

SIGNIFICANCE

In real-world clinical conditions, efficacy and tolerability for PER combination therapy were observed at low PER doses for the PSE, BTRE, and PTE subpopulations.

PLAIN LANGUAGE SUMMARY

To find out how well the medication perampanel works and whether it is safe for people who have epilepsy after having had a stroke, brain tumor, or head injury, we used information from real-life medical situations in Japan. We looked at the data of about 3700 Japanese patients with epilepsy who were treated with perampanel. We found that perampanel was used at lower doses and better at controlling seizures, and had fewer side effects for patients with epilepsy caused by these etiologies than the control group.

Anti-Apoptotic Effects of AMPA Receptor Antagonist Perampanel in Early Brain Injury After Subarachnoid Hemorrhage in Mice

This study was aimed to investigate if acute neuronal apoptosis is induced by activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptors (AMPARs) and inhibited by a clinically available selective AMPAR antagonist and antiepileptic drug perampanel (PER) in subarachnoid hemorrhage (SAH), and if the mechanisms include upregulation of an inflammation-related matricellular protein periostin. Sham-operated and endovascular perforation SAH mice randomly received an administration of 3 mg/kg PER or the vehicle intraperitoneally. Post-SAH neurological impairments and increased caspase-dependent neuronal apoptosis were associated with activation of AMPAR subunits GluA1 and GluA2, and upregulation of periostin and proinflammatory cytokines interleukins-1β and -6, all of which were suppressed by PER. PER also inhibited post-SAH convulsion-unrelated increases in the total spectral power on video electroencephalogram (EEG) monitoring. Intracerebroventricularly injected recombinant periostin blocked PER's anti-apoptotic effects on neurons. An intracerebroventricular injection of a selective agonist for GluA1 and GluA2 aggravated neurological impairment, neuronal apoptosis as well as periostin upregulation, but did not increase the EEG total spectral power after SAH. A higher dosage (10 mg/kg) of PER had even more anti-apoptotic effects compared with 3 mg/kg PER. Thus, this study first showed that AMPAR activation causes post-SAH neuronal apoptosis at least partly via periostin upregulation. A clinically available AMPAR antagonist PER appears to be neuroprotective against post-SAH early brain injury through the anti-inflammatory and anti-apoptotic effects, independent of the antiepileptic action, and deserves further study.

SIRT3 Activation a Promise in Drug Development? New Insights into SIRT3 Biology and Its Implications on the Drug Discovery Process

Sirtuins catalyze deacetylation of lysine residues with a NAD+-dependent mechanism. In mammals, the sirtuin family is composed of seven members, divided into four subclasses that differ in substrate specificity, subcellular localization, regulation, as well as interactions with other proteins, both within and outside the epigenetic field. Recently, much interest has been growing in SIRT3, which is mainly involved in regulating mitochondrial metabolism. Moreover, SIRT3 seems to be protective in diseases such as age-related, neurodegenerative, liver, kidney, heart, and metabolic ones, as well as in cancer. In most cases, activating SIRT3 could be a promising strategy to tackle these health problems. Here, we summarize the main biological functions, substrates, and interactors of SIRT3, as well as several molecules reported in the literature that are able to modulate SIRT3 activity. Among the activators, some derive from natural products, others from library screening, and others from the classical medicinal chemistry approach.

Proposed mechanisms of tau: relationships to traumatic brain injury, Alzheimer's disease, and epilepsy

Traumatic brain injury (TBI), Alzheimer's disease (AD), and epilepsy share proposed mechanisms of injury, including neuronal excitotoxicity, cascade signaling, and activation of protein biomarkers such as tau. Although tau is typically present intracellularly, in tauopathies, phosphorylated (p-) and hyper-phosphorylated (hp-) tau are released extracellularly, the latter leading to decreased neuronal stability and neurofibrillary tangles (NFTs). Tau cleavage at particular sites increases susceptibility to hyper-phosphorylation, NFT formation, and eventual cell death. The relationship between tau and inflammation, however, is unknown. In this review, we present evidence for an imbalanced endoplasmic reticulum (ER) stress response and inflammatory signaling pathways resulting in atypical p-tau, hp-tau and NFT formation. Further, we propose tau as a biomarker for neuronal injury severity in TBI, AD, and epilepsy. We present a hypothesis of tau phosphorylation as an initial acute neuroprotective response to seizures/TBI. However, if the underlying seizure pathology or TBI recurrence is not effectively treated, and the pathway becomes chronically activated, we propose a "tipping point" hypothesis that identifies a transition of tau phosphorylation from neuroprotective to injurious. We outline the role of amyloid beta (Aβ) as a "last ditch effort" to revert the cell to programmed death signaling, that, when fails, transitions the mechanism from injurious to neurodegenerative. Lastly, we discuss targets along these pathways for therapeutic intervention in AD, TBI, and epilepsy.

Perampanel attenuates oxidative stress and pyroptosis following subarachnoid hemorrhage via the SIRT3/FOXO3α pathway

Subarachnoid hemorrhage (SAH) occurs most commonly after rupture of an aneurysm, resulting in high disability and mortality due to the absence of effective therapy. Its subsequent stage, early brain injury (EBI), promotes the sustainable development of injury in the brain and ultimately leads to poor prognosis. As a new antiepileptic drug, the effect of perampanel on EBI after SAH is unknown. Pyroptosis, a process of inflammatory programmed cell death, has been confirmed in most studies to play a substantial role in aggravating SAH-post EBI. Similarly, oxidative stress is closely involved in neuronal pyroptosis and the pathophysiological mechanism of SAH-post EBI, leading to a devastating outcome for SAH patients. Nonetheless, no studies have been conducted to determine whether perampanel reduces pyroptosis and oxidative stress in the context of SAH-induced EBI. Rat SAH model via endovascular perforation was constructed in this study, to assess the neuroprotective effect of perampanel on SAH-post EBI, and to clarify the possible molecular mechanism. By means of the neurological score, brain edema detection, FJB staining, immunofluorescence, WB, ELISA, and ROS assay, we found that perampanel can improve neuroscores and reduce brain edema and neuronal degeneration at 24 h after SAH; we also found that perampanel reduced oxidative stress, neuronal pyroptosis, and inhibition of the SIRT3-FOXO3α pathway at 24 h after SAH. When 3-TYP, an inhibitor of SIRT3, was administered, the effects of perampanel on the SIRT3-FOXO3a pathway, antioxidant stress, and neuronal pyroptosis were reversed. Taken together, our data indicate that perampanel attenuates oxidative stress and pyroptosis following subarachnoid hemorrhage via the SIRT3/FOXO3α pathway. This study highlights the application value of perampanel in subarachnoid hemorrhage and lays a foundation for clinical research and later transformation of perampanel in SAH.

Perioperative perampanel administration for early seizure prophylaxis in brain tumor patients

Background

The efficacy of perioperative prophylactic antiepileptic drug therapy in "seizure-naïve" patients with brain tumor, including glioblastoma (GBM), remains controversial. This study investigated whether perampanel (PER) is effective and safe for preventing perioperative onset of epileptic seizures, so-called early seizure, in patients with brain tumors.

Methods

Forty-five patients underwent tumor resection through craniotomy for a primary supratentorial brain tumor at Ehime University Hospital between April 2021 and July 2022. PER was administered from the 1st to the 6th day after surgery for seizure prophylaxis. Occurrence of early seizure, hematological toxicities, and various side effects were recorded on postoperative days 7 and 14. In addition, the clinical course of these patients was compared with 42 brain tumor patients under the same treatment protocol who received levetiracetam (LEV) for seizure prophylaxis between April 2017 and October 2018.

Results

In 45 patients with brain tumor, including GBM, who received PER administration, no early seizures were identified within 7 days postoperatively. No adverse drug reactions such as hematological toxicity, liver or kidney dysfunction, or exanthematous drug eruption were observed in any cases. As side effects, somnolence was reported in 14 patients (31.1%), vertigo in 3 patients (6.7%), and headache in 3 patients (6.7%). Although somnolence and vertigo were difficult to assess in the case of intraparenchymal tumors, particularly GBM, these side effects were not identified in patients with extraparenchymal tumors such as meningiomas, epidermoid cysts, and pituitary adenomas. In addition, no significant differences were identified compared to patients who received LEV.

Conclusion

The efficacy and safety of PER in preventing early seizures among patients with brain tumors were retrospectively evaluated. Perioperative administration of PER to patients with brain tumors may reduce the risk of early seizures without incurring serious side effects, showing no significant differences compared to patients who received LEV.

Ferroptosis and PPAR-gamma in the limelight of brain tumors and edema

Human malignant brain tumors such as gliomas are devastating due to the induction of cerebral edema and neurodegeneration. A major contributor to glioma-induced neurodegeneration has been identified as glutamate. Glutamate promotes cell growth and proliferation in variety of tumor types. Intriguently, glutamate is also an excitatory neurotransmitter and evokes neuronal cell death at high concentrations. Even though glutamate signaling at the receptor and its downstream effectors has been extensively investigated at the molecular level, there has been little insight into how glutamate enters the tumor microenvironment and impacts on metabolic equilibration until recently. Surprisingly, the 12 transmembrane spanning tranporter xCT (SLC7A11) appeared to be a major player in this process, mediating glutamate secretion and ferroptosis. Also, PPARγ is associated with ferroptosis in neurodegeneration, thereby destroying neurons and causing brain swelling. Although these data are intriguing, tumor-associated edema has so far been quoted as of vasogenic origin. Hence, glutamate and PPARγ biology in the process of glioma-induced brain swelling is conceptually challenging. By inhibiting xCT transporter or AMPA receptors in vivo, brain swelling and peritumoral alterations can be mitigated. This review sheds light on the role of glutamate in brain tumors presenting the conceptual challenge that xCT disruption causes ferroptosis activation in malignant brain tumors. Thus, interfering with glutamate takes center stage in forming the basis of a metabolic equilibration approach.

Role of Sirtuin 3 in Degenerative Diseases of the Central Nervous System

An NAD⁺-dependent deacetylase called Sirtuin 3 (Sirt3) is involved in the metabolic processes of the mitochondria, including energy generation, the tricarboxylic acid cycle, and oxidative stress. Sirt3 activation can slow down or prevent mitochondrial dysfunction in response to neurodegenerative disorders, demonstrating a strong neuroprotective impact. The mechanism of Sirt3 in neurodegenerative illnesses has been elucidated over time; it is essential for neuron, astrocyte, and microglial function, and its primary regulatory factors include antiapoptosis, oxidative stress, and the maintenance of metabolic homeostasis. Neurodegenerative disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), may benefit from a thorough and in-depth investigation of Sirt3. In this review, we primarily cover Sirt3's role and its regulation in the nerve cells and the connection between Sirt3 and neurodegenerative disorders.

Role of SIRT3 in mitochondrial biology and its therapeutic implications in neurodegenerative disorders

Sirtuin 3 (SIRT3), a mitochondrial deacetylase expressed preferentially in high-metabolic-demand tissues including the brain, requires NAD⁺ as a cofactor for catalytic activity. It regulates various processes such as energy homeostasis, redox balance, mitochondrial quality control, mitochondrial unfolded protein response (UPRmt), biogenesis, dynamics and mitophagy by altering protein acetylation status. Reduced SIRT3 expression or activity causes hyperacetylation of hundreds of mitochondrial proteins, which has been linked with neurological abnormalities, neuro-excitotoxicity and neuronal cell death. A body of evidence has suggested, SIRT3 activation as a potential therapeutic modality for age-related brain abnormalities and neurodegenerative disorders.

Immune regulation in neurovascular units after traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Survivors may experience movement disorders, memory loss, and cognitive deficits. However, there is a lack of understanding of the pathophysiology of TBI-mediated neuroinflammation and neurodegeneration. The immune regulation process of TBI involves changes in the peripheral and central nervous system (CNS) immunity, and intracranial blood vessels are essential communication centers. The neurovascular unit (NVU) is responsible for coupling blood flow with brain activity, and comprises endothelial cells, pericytes, astrocyte end-feet, and vast regulatory nerve terminals. A stable NVU is the basis for normal brain function. The concept of the NVU emphasizes that cell-cell interactions between different types of cells are essential for maintaining brain homeostasis. Previous studies have explored the effects of immune system changes after TBI. The NVU can help us further understand the immune regulation process. Herein, we enumerate the paradoxes of primary immune activation and chronic immunosuppression. We describe the changes in immune cells, cytokines/chemokines, and neuroinflammation after TBI. The post-immunomodulatory changes in NVU components are discussed, and research exploring immune changes in the NVU pattern is also described. Finally, we summarize immune regulation therapies and drugs after TBI. Therapies and drugs that focus on immune regulation have shown great potential for neuroprotection. These findings will help us further understand the pathological processes after TBI.

Sirtuin-3: A potential target for treating several types of brain injury

Sirtuin-3 (SIRT3) is responsible for maintaining mitochondrial homeostasis by deacetylating substrates in an NAD+-dependent manner. SIRT3, the primary deacetylase located in the mitochondria, controls cellular energy metabolism and the synthesis of essential biomolecules for cell survival. In recent years, increasing evidence has shown that SIRT3 is involved in several types of acute brain injury. In ischaemic stroke, subarachnoid haemorrhage, traumatic brain injury, and intracerebral haemorrhage, SIRT3 is closely related to mitochondrial homeostasis and with the mechanisms of pathophysiological processes such as neuroinflammation, oxidative stress, autophagy, and programmed cell death. As SIRT3 is the driver and regulator of a variety of pathophysiological processes, its molecular regulation is significant. In this paper, we review the role of SIRT3 in various types of brain injury and summarise SIRT3 molecular regulation. Numerous studies have demonstrated that SIRT3 plays a protective role in various types of brain injury. Here, we present the current research available on SIRT3 as a target for treating ischaemic stroke, subarachnoid haemorrhage, traumatic brain injury, thus highlighting the therapeutic potential of SIRT3 as a potent mediator of catastrophic brain injury. In addition, we have summarised the therapeutic drugs, compounds, natural extracts, peptides, physical stimuli, and other small molecules that may regulate SIRT3 to uncover additional brain-protective mechanisms of SIRT3, conduct further research, and provide more evidence for clinical transformation and drug development.

A Promising Strategy to Treat Neurodegenerative Diseases by SIRT3 Activation

SIRT3, the primary mitochondrial deacetylase, regulates the functions of mitochondrial proteins including metabolic enzymes and respiratory chain components. Although SIRT3's functions in peripheral tissues are well established, the significance of its downregulation in neurodegenerative diseases is beginning to emerge. SIRT3 plays a key role in brain energy metabolism and provides substrate flexibility to neurons. It also facilitates metabolic coupling between fuel substrate-producing tissues and fuel-consuming tissues. SIRT3 mediates the health benefits of lifestyle-based modifications such as calorie restriction and exercise. SIRT3 deficiency is associated with metabolic syndrome (MetS), a precondition for diseases including obesity, diabetes, and cardiovascular disease. The pure form of Alzheimer's disease (AD) is rare, and it has been reported to coexist with these diseases in aging populations. SIRT3 downregulation leads to mitochondrial dysfunction, neuroinflammation, and inflammation, potentially triggering factors of AD pathogenesis. Recent studies have also suggested that SIRT3 may act through multiple pathways to reduce plaque formation in the AD brain. In this review, we give an overview of SIRT3's roles in brain physiology and pathology and discuss several activators of SIRT3 that can be considered potential therapeutic agents for the treatment of dementia.

Bioinformatics and network pharmacology analysis of drug targets and mechanisms related to the comorbidity of epilepsy and migraine

OBJECTIVE

The present study aimed to explore the mechanisms underlying the comorbidity of epilepsy and migraine, identify potential common targets for drug intervention, and provide insight into new avenues for disease prevention and treatment using an integrated bioinformatic and network pharmacology approach.

METHODS

Disease targets in epilepsy and migraine were screened using the DisGeNET database to identify intersecting gene targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) enrichment analyses were then performed using the WebGestalt database. Furthermore, the STRING database was used to construct a protein-protein interaction (PPI) network, and Cytoscape software was used to analyze the protein molecular signals at the intersection of epilepsy and migraine. The Drugbank database was used to identify common targets for antiepileptic drugs in epilepsy and migraine to further analyze the disease-gene-target-drug interaction network. Finally, molecular docking simulations were performed to verify the hypothesis that migraine and epilepsy share common diseases and drug targets.

RESULTS

A total of 178 common targets for epilepsy and migraine were identified using the DisGeNET database, and the 24 genes most related to the diseases were screened using the Score_gda gene scoring system. GO enrichment analysis indicated that common targets were mainly enriched in biological processes and molecular functions, including membrane potential regulation, inorganic ion transmembrane transport, axonal signaling, and ion channel activity. KEGG pathway enrichment analysis indicated that the mechanism of action might be related to neuroactive ligand receptors, AGE-RAGE, cAMP, and VEGF signaling pathways. The PPI network construction and analysis results showed that the PPI grid had 23 central nodes and 24 connected edges, with an average node degree of 2.09 and an average clustering coefficient of 0.384. The 10 genes with potentially important roles in epilepsy and migraine were CACNA1A, KCNQ2, KCNA1, SCN1A, PRRT2, SCN8A, KCNQ3, SCN2A, GRIN2A, and GABRG2. Drugbank database results indicated that antiepileptic drugs, including lamotrigine, topiramate, valproic acid, carbamazepine, gabapentin, and perampanel, also had common targets with migraine. The three most important targets exhibited strong binding affinity with drugs in the molecular docking simulations.

CONCLUSION

Our systematic and comprehensive analyses of disease-gene-target-drug interaction networks identified several biological processes and molecular functions common to migraine and epilepsy, most of which were related to neuroactive ligand-receptor interactions. These data provide a new theoretical basis and reference for the clinical treatment of comorbid epilepsy and migraine and may aid in the development of novel pharmacological strategies.

Sirtuins functions in central nervous system cells under neurological disorders

The sirtuins (SIRTs), a class of NAD+ -dependent deacylases, contain seven SIRT family members in mammals, from SIRT1 to SIRT7. Extensive studies have revealed that SIRT proteins regulate virous cell functions. Central nervous system (CNS) decline resulted in progressive cognitive impairment, social and physical abilities dysfunction. Therefore, it is of vital importance to have a better understanding of potential target to promote homeostasis of CNS. SIRTs have merged as the underlying regulating factors of the process of neurological disorders. In this review, we profile multiple functions of SIRT proteins in different cells during brain function and under CNS injury.

Adiponectin/AdiopR1 signaling prevents mitochondrial dysfunction and oxidative injury after traumatic brain injury in a SIRT3 dependent manner

Mitochondrial dysfunction and oxidative injury, which contribute to worsening of neurological deficits and poor clinical outcomes, are hallmarks of secondary brain injury after TBI. Adiponectin (APN), beyond its well-established regulatory effects on metabolism, is also essential for maintaining normal brain functions by binding APN receptors that are ubiquitously expressed in the brain. Currently, the significance of the APN/APN receptor (AdipoR) signaling pathway in secondary injury after TBI and the specific mechanisms have not been conclusively determined. In this study, we found that APN knockout aggravated brain functional deficits, increased brain edema and lesion volume, and exacerbated oxidative stress as well as apoptosis after TBI. These effects were significantly alleviated after APN receptor agonist (AdipoRon) treatment. Moreover, we found that AdipoR1, rather than AdipoR2, mediated the protective effects of APN/AdipoR signaling against oxidative stress and brain injury after TBI. In neuron-specific AdipoR1 knockout mice, mitochondrial damage was more severe after TBI, indicating a potential association between APN/AdipoR1 signaling inactivation and mitochondrial damage. Mechanistically, neuron-specific knockout of SIRT3, the most important deacetylase in the mitochondria, reversed the neuroprotective effects of AdipoRon after TBI. Then, PRDX3, a critical antioxidant enzyme in the mitochondria, was identified as a vital downstream target of the APN/SIRT3 axis to alleviate oxidative injury after TBI. Finally, we revealed that APN/AdipoR1 signaling promotes SIRT3 transcription by activating the AMPK-PGC pathway. In conclusion, APN/AdipoR1 signaling plays a protective role in post-TBI oxidative damage by restoring the SIRT3-mediated mitochondrial homeostasis and antioxidant system.

Application and advantages of zebrafish model in the study of neurovascular unit

The concept of "Neurovascular Unit" (NVU) was put forward, so that the research goal of Central Nervous System (CNS) diseases gradually transitioned from a single neuron to the structural and functional integrity of the NVU. Zebrafish has the advantages of high homology with human genes, strong reproductive capacity and visualization of neural circuits, so it has become an emerging model organism for NVU research and has been applied to a variety of CNS diseases. Based on CNKI (https://www.cnki.net/) and PubMed (https://pubmed.ncbi.nlm.nih.gov/about/) databases, the author of this article sorted out the relevant literature, analyzed the construction of a zebrafish model of various CNS diseases，and the use of diagrams showed the application of zebrafish in the NVU, revealed its relationship, which would provide new methods and references for the treatment and research of CNS diseases.

Blood-Brain Barrier Dysfunction Amplifies the Development of Neuroinflammation: Understanding of Cellular Events in Brain Microvascular Endothelial Cells for Prevention and Treatment of BBB Dysfunction

Neuroinflammation is involved in the onset or progression of various neurodegenerative diseases. Initiation of neuroinflammation is triggered by endogenous substances (damage-associated molecular patterns) and/or exogenous pathogens. Activation of glial cells (microglia and astrocytes) is widely recognized as a hallmark of neuroinflammation and triggers the release of proinflammatory cytokines, leading to neurotoxicity and neuronal dysfunction. Another feature associated with neuroinflammatory diseases is impairment of the blood-brain barrier (BBB). The BBB, which is composed of brain endothelial cells connected by tight junctions, maintains brain homeostasis and protects neurons. Impairment of this barrier allows trafficking of immune cells or plasma proteins into the brain parenchyma and subsequent inflammatory processes in the brain. Besides neurons, activated glial cells also affect BBB integrity. Therefore, BBB dysfunction can amplify neuroinflammation and act as a key process in the development of neuroinflammation. BBB integrity is determined by the integration of multiple signaling pathways within brain endothelial cells through intercellular communication between brain endothelial cells and brain perivascular cells (pericytes, astrocytes, microglia, and oligodendrocytes). For prevention of BBB disruption, both cellular components, such as signaling molecules in brain endothelial cells, and non-cellular components, such as inflammatory mediators released by perivascular cells, should be considered. Thus, understanding of intracellular signaling pathways that disrupt the BBB can provide novel treatments for neurological diseases associated with neuroinflammation. In this review, we discuss current knowledge regarding the underlying mechanisms involved in BBB impairment by inflammatory mediators released by perivascular cells.

Perampanel, an AMPAR antagonist, alleviates experimental intracerebral hemorrhage‑induced brain injury via necroptosis and neuroinflammation

Spontaneous intracerebral hemorrhage (ICH) is a subtype of stroke with high mortality and morbidity due to the lack of effective therapies. The alpha‑amino‑3‑hydroxy‑5‑methyl‑4‑isoxazolepropionic acid receptor antagonist perampanel has been reported to alleviate early brain injury following subarachnoid hemorrhage and traumatic brain injury by reducing reactive oxygen species, apoptosis, autophagy, and necroptosis. Necroptosis is a caspase‑independent programmed cell death mechanism that serves a vital role in neuronal cell death following ICH. However, the precise role of necroptosis in perampanel‑mediated neuroprotection following ICH has not been confirmed. The present study aimed to investigate the neuroprotective effects and potential molecular mechanisms of perampanel in ICH‑induced early brain injury by regulating neural necroptosis in C57BL/6 mice and in a hemin‑induced neuron damage cell culture model. Mortality, neurological score, brain water content, and neuronal death were evaluated. The results demonstrated that perampanel treatment increased the survival rate and neurological score, and increased neuron survival. In addition, perampanel treatment downregulated the protein expression levels of receptor interacting serine/threonine kinase (RIP) 1, RIP3, and mixed lineage kinase domain like pseudokinase, and of the cytokines IL‑1β, IL‑6, TNF‑α, and NF‑κB. These results indicated that perampanel‑mediated inhibition of necroptosis and neuroinflammation ameliorated neuronal death in vitro and in vivo following ICH. The neuroprotective capacity of perampanel was partly dependent on the PTEN pathway. Taken together, the results of the present study demonstrated that perampanel improved neurological outcomes in mice and reduced neuronal death by protecting against neural necroptosis and neuroinflammation.

Effects of Lipotoxicity in Brain Microvascular Endothelial Cells During Sirt3 Deficiency-Potential Role in Comorbid Alzheimer's Disease

Silence information regulator 3 (SIRT3) is an NAD⁺ dependent deacetylase enzyme that enhances the function of key mitochondrial proteins. We have earlier demonstrated that deletion of Sirt3 gene leads to downregulation of metabolic enzymes, mitochondrial dysfunction and neuroinflammation in the brain, the major causes of Alzheimer’s disease (AD). We also reported recently that Sirt3 gene deletion in Alzheimer’s transgenic mice leads to exacerbation of neuroinflammation, amyloid plaque deposition and microglial activation. AD often coexists with other brain lesions caused by comorbidities which can exert their deleterious effects through the neurovascular unit. This unit consists of brain microvascular endothelial cells (BMECs), end feet of astrocytes, and pericytes. BMECs are uniquely different from other vascular endothelial cells because they are glued together by tight-junction proteins. BMECs are in constant contact with circulating factors as they line the luminal side. Therefore, we hypothesized that vascular endothelial injury caused by comorbidities plays a significant role in neuroinflammation. Herein, we investigated the effects of lipotoxicity in BMECs and how Sirt3 deficiency facilitate the deleterious effects of lipotoxicity on them using in vivo and in vitro models. We observed decreases in the levels of SIRT3 and tight junction proteins in the brain samples of western diet-fed APP/PS1 mice. Similar observations were obtained with Alzheimer’s post-mortem samples. Exposure of BEND3 cells, mouse brain-derived Endothelial cells3, to a combination of high glucose and palmitic acid resulted in significant (P < 0.01-P < 0.001) decreases in the levels of SIRT3, claudin-5 and ZO-1. Induction of inflammatory mediators, including Cox-2, CXCL1, RANTES, and GADD45β was also observed in these treated cells. Interestingly, the induction was more with Sirt3-silenced BEND3 cells, suggesting that Sirt3 deficiency exacerbates inflammatory response. Palmitic acid was more potent in inducing the inflammatory mediators. Significant cytotoxicity and changes in microglial morphology were observed when cocultures of Sirt3-silenced BEND3 and Sirt3-silenced BV2 cells were exposed to palmitic acid. Transendothelial electrical resistance measurement with these cocultures suggested decreased barrier integrity. The findings of this study suggest that hyperlipidemia in comorbidities can compromise blood brain barrier integrity by inducing inflammatory mediators and decreasing tight junction proteins in the vascular endothelial cells of the AD brain, leading to activation of microglia.