Blood-brain barrier dysfunction in ischemic stroke: targeting tight junctions and transporters for vascular protection

Blockage of p38MAPK in astrocytes alleviates brain damage in a mouse model of embolic stroke through the CX43/AQP4 axis

BACKGROUND

Cerebral edema, a significant complication arising from acute ischemic stroke (IS), has a critical influence on morbidity and mortality. p38MAPK has been shown to promote neuronal apoptosis and brain damage. However, the role of the p38MAPK inhibitor SKF-86002 in protecting against ischemic injury and cerebral edema remains unclear.

METHODS

Infarct area was examined by TTC staining in middle cerebral artery occlusion (MCAO) mice. Neurological score and brain water content were evaluated. TUNEL and NeuN staining were used to assess neuronal apoptosis and the survival of neurons. Blood-brain barrier (BBB) permeability was determined by Evans blue. Double immunofluorescence staining detected the colocalization of AQP4 and CX43 in astrocytes. IHC staining revealed CX43 and AQP4 expression. EDU staining detected the proliferation of Oxygen and glucose deprivation/reoxygenation (OGD/R)-treated astrocytes. Levels of oxidative stress markers were determined using commercial kits. ELISA was used to assess the secretion of pro-inflammatory factors. RT-qPCR measured the expression of CX43, AQP4 and pro-inflammatory factors. Western blot analyzed the levels of p-p38/p38, AQP4 and CX43. Co-immunoprecipitation (Co-IP) determined the interaction between CX43 and AQP4.

RESULTS

SKF-86002 attenuated brain damage, edema, and neuronal apoptosis in MCAO mice. Astrocyte proliferation was suppressed, and oxidative stress and inflammation were alleviated by SKF-86002 treatment. SKF-86002 negatively regulated p38 signaling and the expression of AQP4 and CX43. Additionally, the expression of CX43/AQP4 within astrocytes was modulated by SKF-86002.

CONCLUSION

In summary, SKF-86002 alleviated IS injury and cerebral edema by inhibiting astrocyte proliferation, oxidative stress and inflammation. This effect was associated with the suppression of CX43/AQP4, suggesting that SKF-86002 shows promise as a novel therapeutic approach for preventing IS.

Blood-Brain Barrier-Penetrating Metal-Organic Framework Antioxidant Nanozymes for Targeted Ischemic Stroke Therapy

Overproduction of reactive oxygen species (ROS) during reperfusion in ischemic stroke (IS) severely impedes neuronal survival and results in high rates of morbidity and disability. The effective blood-brain barrier (BBB) penetration and brain delivery of antioxidative agents remain the biggest challenge in treating ischemic reperfusion-induced cerebrovascular and neural injury. In this study, a metal-organic framework (MOF) nanozyme (MIL-101-NH2(Fe/Cu)) with ROS scavenging activities to encapsulate neuroprotective agent rapamycin is fabricated and decorating the exterior with BBB-targeting protein ligands (transferrin), thereby realizing enhanced drug retention and controlled release within ischemic lesions for the synergistic treatment of IS. Through the receptor-mediated transcellular pathway, the transferrin-coated MOF nanoparticles achieved efficient transport across the BBB and targeted accumulation at the cerebral ischemic injury site of mice with middle cerebral artery occlusion/reperfusion (MCAO/R), wherein the nanocarrier exhibited catalytic activities of ROS decomposition into O2 and H2O2-responsive rapamycin release. By its BBB-targeting, antioxidative, anti-inflammatory, and antiapoptotic properties, the MOF nanosystem addressed multiple pathological factors of IS and realized remarkable neuroprotective effects, leading to the substantial reduction of cerebral infarction volume and accelerated recovery of nerve functions in the MCAO/R mouse model. This MOF-based nanomedicine provides valuable design principles for effective IS therapy with multi-mechanism synergies.

α7nACh receptor, a promising target to reduce BBB damage by regulating inflammation and autophagy after ischemic stroke

Increased blood-brain barrier (BBB) permeability can lead to cerebral vasogenic edema and hemorrhagic transformation (HT) after reperfusion with tissue plasminogen activator (tPA), the only United States Food and Drug Administration (FDA)-approved treatment for acute ischemia stroke (AIS). The therapeutic benefits of tPA after AIS are partially outweighed by a more than a six-fold increase in the risk of symptomatic intracerebral hemorrhage. Therefore, strategies to protect the integrity of BBB are urgently needed to reduce HT and vasogenic edema after tPA thrombolysis or endovascular thrombectomy. Interestingly, an NIH study showed that smokers treated with tPA had a significantly lower prevalence of brain hemorrhage than nonsmokers, suggesting that cigarette smoking may protect patients treated with tPA from the side effects of cerebral hemorrhage. Importantly, we recently showed that treatment with nicotine reduces AIS-induced BBB damage and that modulating α7nAChR by modulation could reduce ischemia/reperfusion-induced BBB damage, suggesting that α7nAChR could be a potential target to reduce BBB after AIS. In this review, we first provide an overview of stroke and the impact of α7nAChR activation on BBB damage. Next, we discuss the features and mechanism of BBB destruction after AIS. We then discuss the effect of nicotine effect on BBB integrity as well as the mechanism underlying those effects. Finally, we discuss the side effects and potential strategies for modulating α7nAChR to reduce AIS-induced BBB damage.

Targeting PI3K/Akt in Cerebral Ischemia Reperfusion Injury Alleviation: From Signaling Networks to Targeted Therapy

Ischemia/reperfusion (I/R) injury is a pathological event that results in reperfusion due to low blood flow to an organ. Cerebral ischemia is a common cerebrovascular disease with high mortality, and reperfusion is the current standard intervention. However, reperfusion may further induce cellular damage and dysfunction known as cerebral ischemia/reperfusion injury (CIRI). Currently, strategies for the clinical management of CIRI are limited, necessitating the exploration of novel and efficacious treatment modalities for the benefit of patients. PI3K/Akt signaling pathway is an important cellular process associated with the disease. Stimulation of the PI3K/Akt pathway enhances I/R injury in multiple organs such as heart, brain, lung, and liver. It stands as a pivotal signaling pathway crucial for diminishing cerebral infarction size and safeguarding the functionality of brain tissue after CIRI. During CIRI, activation of the PI3K/Akt pathway exhibits a protective effect on CIRI. Furthermore, activation of the PI3K/Akt pathway has the potential to augment the activity of antioxidant enzymes, resulting in a decrease in reactive oxygen species (ROS) and the associated oxidative stress. Meanwhile, PI3K/Akt plays a neuroprotective role by inhibiting inflammatory responses and apoptosis. For example, PI3K/Akt interacts with NF-κB, Nrf2, and MAPK signaling pathways to mitigate CIRI. This article is aimed to explore the pivotal role and underlying mechanism of PI3K/Akt in ameliorating CIRI and investigate the influence of ischemic preconditioning and post-processing, as well as the impact of pertinent drugs or activators targeting the PI3K/Akt pathway on CIRI. The primary objective is to furnish compelling evidence supporting the activation of PI3K/Akt in the context of CIRI, elucidating its mechanistic intricacies. By doing so, the paper aims to underscore the critical contribution of PI3K/Akt in mitigating CIRI, providing a theoretical foundation for considering the PI3K/Akt pathway as a viable target for CIRI treatment.

Integrative microbiomics, proteomics and lipidomics studies unraveled the preventive mechanism of Shouhui Tongbian Capsules on cerebral ischemic stroke injury

ETHNOPHARMACOLOGICAL RELEVANCE

Cerebral ischemic stroke (CIS) is one of the most important factors leading to death and disability, which seriously threaten the survival and health of patients. The intentional flora and its derived metabolites are demonstrated to play vital roles in the physiology and onset of CIS. Shouhui Tongbian Capsules (SHTB), a Traditional Chinese Medicine, could regulate gut microbiota and metabolites. Study has found that SHTB has protective effect on CIS, but the mechanism is still unclear.

AIM OF STUDY

This study was designed to evaluate the preventive effects and the mechanism of SHTB on CIS injury.

MATERIALS AND METHODS

The rats were pretreated with SHTB for 5 days, then the middle cerebral artery occlusion/reperfusion (MCAO/R) was established. Neurological deficit score, TTC staining, brain water content, H&E and Nissl staining were preformed to evaluate the preventive effects of SHTB on CIS. The Occludin and ZO-1 were analyzed to evaluate the blood-brain barrier (BBB). 16S rDNA sequencing and LC-ESI-MS/MS-based metabolomics profiling were performed to analyze the gut microbiota composition and short chain fatty acids (SCFAs) profile in gut. Serum lipopolysaccharide specific IgA antibody (LPS-SIgA) and diamine oxidase (DAO), as well as colon Claudin 5 and ZO-1 were analyzed to evaluate the intestinal barrier. Proteomics was used to evaluated the proteins profile in brain. Lipidomics were used to evaluate the brain SCFAs as well as medium and long chain fatty acids (MCFAs and LCFAs). Malondialdehyde (MDA), Total Superoxide dismutase (T-SOD), Glutathione (GSH), Glutathione peroxidase (GSH-Px), Catalase (CAT) and reactive oxygen species (ROS) were assayed to evaluate the oxidative stress in brain. Western blot was performed to evaluate the expression of PPARγ, Nrf2, SLC3A2, SCL7A11, GPX4, ACSL4 and LOX.

RESULTS

SHTB prevented rats from MCAO/R injury, which was confirmed by lower cerebral infarct rate, brain water content, neurological deficit score and nissl body loss, and improved brain pathology. Meanwhile, SHTB upregulated the expression of ZO-1 and Occludin to maintain the integrity of BBB. 16S rDNA sequencing and LC-ESI-MS/MS-based targeted metabolomics found that SHTB increased the abundance of gut microbiota, regulated the numbers of intestinal bacteria to increase the production of Acetic acid, Propionic acid, and Butyric acid, as well as decrease the production of Valeric acid and Hexanoic acid in the gut. Meanwhile, SHTB improved the intestinal barrier by upregulating the protein levels of Claudin 5 and ZO-1, which was confirmed by low concentrations of LPS-SIgA and DAO in serum. Multi omics and spearman correlation analysis indicated that SHTB regulated the abundance of Escherichia-Shigella and Lactobacillus to increase Acetic acid, Propionic acid, and Butyric acid to induce the expression of PPARγ, thereby regulating fatty acid metabolism and degradation, improving lipid metabolism disorders, downregulating lipid oxidative stress, inhibiting ferroptosis, and alleviating brain injury.

CONCLUSION

This study confirmed that SHTB improved the disturbance of fatty acid metabolism in brain tissue by regulating gut microbiota and the production of fecal SCFAs to inhibit ferroptosis caused by lipid oxidative stress and prevent CIS injury, which provided a potential candidate drug for the prevention of CIS.

Electroacupuncture Promotes the Generation of Intestinal Treg Cells After Ischemic Stroke by Foxp3 Acetylation Regulation

Electroacupuncture (EA) has been shown to ameliorate brain injury and protect against intestinal injury after ischemic stroke. These protective effects are closely associated with the enhancement of regulatory T (Treg) cell numbers and function in the intestine, as well as the inhibition of intestinal γδ T cell production and their migration to the brain. This study aimed to elucidate the potential mechanism by which EA regulates intestinal Treg cell differentiation after stroke. Sprague-Dawley rats were divided into three groups: the sham group, the middle cerebral artery occlusion (MCAO) group, and the MCAO plus EA (MEA) group. The MCAO model was generated by occluding the middle cerebral artery. EA was applied to Baihui (GV20) acupoint once daily. Samples were collected 3 days after reperfusion. Our results showed that EA reduced the inflammatory response in the brain and intestine after ischemic stroke. EA treatment increased the percentage of Treg cells in the small intestine of rats. EA increased the levels of SCFAs, while also inhibiting histone deacetylase activity (HDAC). Additionally, acetylated Foxp3 protein in the small intestine was increased after EA treatment. These results suggest that EA at GV20 alleviates brain and intestinal inflammatory injury in stroke rats, potentially through the enhancement of SCFA-mediated Foxp3 acetylation in Treg cells.

IL-33 in Ischemic Stroke: Brain vs. Periphery

Cerebrovascular disease is the second-leading cause of death and disability worldwide, with stroke being the most common cause. In ischemic stroke, several processes combine to produce immunosuppression, leaving the post-stroke body susceptible to infection, which in turn affects neuroinflammation. Interleukin-33 (IL-33), a member of the interleukin-1 family (IL-1), functions as a modulator of immune responses and inflammation, playing a crucial role in the establishment of immunologic responses. IL-33 has been shown to have a protective effect on brain injury and represents a potential target by modulating inflammatory cytokines and stimulating immune regulatory cells. With an emphasis on preclinical and clinical studies, this review covers the impact of IL-33 on immune system mechanisms following ischemic stroke.

CircRNA_0003307 promoted brain microvascular endothelial cell angiogenesis, invasion, and migration in cerebral ischemia-reperfusion injury: Potential involvement of miRNA-191-5p/CDK6 pathway

BACKGROUNDS

The role of miR-191-5p in cerebral ischemia-reperfusion (I/R) injury has been established, with its expression in endothelial cells demonstrating anti-angiogenic effects. A potential circular RNA, circRNA_0003307, has been identified through bioinformatics analysis as a candidate for interaction with miR-191-5p, yet its functional significance in brain I/R injury remains unexplored. We aimed to investigate whether circRNA_0003307 regulates brain microvascular endothelial cell (BMEC) vascular tube formation, invasion, and migration by regulating the miR-191-5p cascade.

METHODS

Mouse BMECs (bEnd.3) were culturedand exposed to oxygen-glucose deprivation (OGD). The effects of circRNA_0003307 on vessel-like tube formation and cellular migration were examined. In addition, we investigated the protective effects of circRNA_0003307 on I/R injury in mice.

RESULTS

The results showed the level of circRNA_0003307 was concentration-dependently increased in OGD-induced bEnd.3 cells. ODG-induction enhanced angiogenesis, migration, and invasion of bEnd.3 cells, which were further promoted by the transfection of pcDNA-0003307. Silencing circRNA_0003307 expression showed the opposite results. The dual luciferase assay demonstrated miRNA-191-5p interacted with circRNA_00033073' UTR, and miRNA-191-5p could bind with CDK6. Meanwhile, circRNA_0003307 promoted the expression of CDK6 by sponging miRNA-191-5p. The overexpression of circRNA_0003307 activated the angiogenesis, migration, and invasion of OGD-induced bEnd.3 cells, which were hindered by miRNA-191-5p mimic or siRNA-CDK6. Thus, circRNA_0003307 promoted ODG-induced angiogenesis, migration, and invasion of bEnd.3 cells by targeting miR-191-5p/CDK6 axis. In vivo, circRNA_0003307 had protective effects on brain I/R injury, including neuroprotection, anti-apoptosis and angiogenesis.

CONCLUSION

CircRNA_0003307 may be a promisingtherapeutictarget forthe treatment of cerebral I/R injury.

The protective effects of apelin-13 in HIV-1 tat- induced macrophage infiltration and BBB impairment

Impairment of the blood - brain barrier (BBB) and subsequent inflammatory responses contribute to the development of human immunodeficiency virus (HIV)-1-associated neurocognitive disorders (HAND). Apelin-13, the most abundant member of the apelin family, acts as the ligand of the angiotensin receptor-like 1 (APJ). However, its pharmacological function in HAND and its underlying mechanism are unknown. In the current study, we report that the presence of HIV-1 Tat reduced the levels of Apelin-13 and APJ in the cortex tissue of mice. Importantly, Apelin-13 preserved BBB integrity against HIV-1 Tat in mice by increasing the expression of the tight junction protein zonula occludens-1 (ZO-1) and occludin. Interestingly, increased macrophage infiltration, indicated by elevated CD68-positive staining was observed in the cortex after stimulation with HIV-1, which was mitigated by the administration of Apelin-13. Correspondingly, Apelin-13 reduced the expression of monocyte chemoattractant protein-1; (MCP-1). An in vitro two-chamber and two-cell trans-well assay demonstrated that HIV-1 Tat challenge significantly promoted macrophage migration, which was notably attenuated by the introduction of Apelin-13. Accordingly, treatment with Apelin-13 restored the HIV-1 Tat-induced reduction of occludin and ZO-1, while preventing the upregulation of MCP-1 in human brain microvascular endothelial cells (HBMVECs). Our results suggest that Apelin-13 may reduce macrophage infiltration into brain tissues and mitigate BBB dysfunction in patients with HAND.

Candesartan restores blood-brain barrier dysfunction, mitigates aberrant gene expression, and extends lifespan in a knockin mouse model of epileptogenesis

Blockade of Angiotensin type 1 receptor (AT1R) has potential therapeutic utility in the treatment of numerous detrimental consequences of epileptogenesis, including oxidative stress, neuroinflammation, and blood-brain barrier (BBB) dysfunction. We have recently shown that many of these pathological processes play a critical role in seizure onset and propagation in the Scn8a-N1768D mouse model. Here we investigate the efficacy and potential mechanism(s) of action of candesartan (CND), an FDA-approved angiotensin receptor blocker (ARB) indicated for hypertension, in improving outcomes in this model of pediatric epilepsy. We compared length of lifespan, seizure frequency, and BBB permeability in juvenile (D/D) and adult (D/+) mice treated with CND at times after seizure onset. We performed RNAseq on hippocampal tissue to quantify differences in genome-wide patterns of transcript abundance and inferred beneficial and detrimental effects of canonical pathways identified by enrichment methods in untreated and treated mice. Our results demonstrate that treatment with CND gives rise to increased survival, longer periods of seizure freedom, and diminished BBB permeability. CND treatment also partially reversed or 'normalized' disease-induced genome-wide gene expression profiles associated with inhibition of NF-κB, TNFα, IL-6, and TGF-β signaling in juvenile and adult mice. Pathway analyses reveal that efficacy of CND is due to its known dual mechanism of action as both an AT1R antagonist and a PPARγ agonist. The robust effectiveness of CND across ages, sexes and mouse strains is a positive indication for its translation to humans and its suitability of use for clinical trials in children with SCN8A epilepsy.

Senescence-associated microvascular endothelial dysfunction: A focus on the blood-brain and blood-retinal barriers

The blood-brain barrier (BBB) and blood-retinal barrier (BRB) constitute critical physiochemical interfaces, precisely orchestrating the bidirectional communication between the brain/retina and blood. Increased permeability or leakage of these barriers has been demonstrably linked to age-related vascular and parenchymal damage. While it has been suggested that the gradual aging process may coincide with disruptions in these barriers, this phenomenon is significantly exacerbated in individuals with age-related neurodegenerative disorders (ARND). This review focuses on the microvascular endothelium, a key constituent of BBB and BRB, highlighting the impact of endothelial senescence on barrier dysfunction and exploring recent discoveries regarding core pathways implicated in its breakdown. Subsequently, we address the "vascular senescence hypothesis" for ARND, with a particular emphasis on Alzheimer's disease and age-related macular degeneration, centered on endothelial senescence. Finally, we discuss potential senotherapeutic strategies targeting barrier dysfunction.

Rosmarinic acid liposomes suppress ferroptosis in ischemic brain via inhibition of TfR1 in BMECs

BACKGROUND

Iron deposition and ferroptosis are involved in ischemic stroke injury, but the choice of drugs for treatment is limited.

PURPOSE

To investigate the potential neuroprotective effects of Rosmarinic acid (RosA) encapsulated within nanoliposomes (RosA-LIP) on ischemic stroke.

METHODS

Wild-type (WT) and TfR1EC cKO (specific knockout of the TfR1 gene in BMECs) mice used to establish a dMCAO model, with simultaneous administration of RosA-LIP (20 mg/kg/d, i.p.) or RosA (20 mg/kg/d, i.p.).

RESULTS

The successful synthesis of RosA-LIP resulted in enhanced stability and precise delivery in both the serum and brain. The administration of RosA-LIP effectively mitigated ischemia-induced behavioral abnormalities and pathological damage. RosA-LIP inhibited ferroptosis by ameliorating mitochondrial abnormalities, increasing GPX4 levels, and decreasing ACSL4/LPCAT3/Lox-dependent lipid peroxidation. RosA-LIP effectively improved blood‒brain barrier (BBB) permeability, increased tight junctions (TJs) protein expression and reduced iron levels in ischemic tissue and brain microvascular endothelial cells (BMECs) by modulating FPN1 and TfR1 levels. Furthermore, RosA-LIP suppressed TfR1 to attenuate ACSL4/LPCAT3/Lox-mediated ferroptosis in TfR1EC cKO mice subjected to dMCAO.

CONCLUSION

RosA-LIP effectively increased the brain level of RosA and protected against ferroptosis through the regulation of TfR1 in BMECs.

Dynamic changes in key factors of the blood-brain barrier in early diabetic mice

Chronic hyperglycemia can result in damage to the hippocampus and dysfunction of the blood-brain barrier (BBB), potentially leading to neurological disorders. This study examined the histological structure of the hippocampus and the expression of critical genes associated with the BBB at 2 early stage time points in a streptozotocin-induced diabetes mellitus (DM) mouse model. Routine histology revealed vascular congestion and dilation of Virchow-Robin spaces in the hippocampal CA1 region of the DM group. Neuronal alterations included rounding and swelling and reduction in Nissl bodies and increased apoptosis. Compared to the control group, TJP1 mRNA expression in the DM group was significantly lower (P < .05 or P < .01), while mRNA levels of JAM3, TJP3, CLDN5, CLDN3, and OCLN initially increased and then decreased. At 7, 14, and 21 days, mRNA levels of the receptor for advanced glycation end products (AGER) were greater in the DM group than in the control group (P < .05 or P < .01). These findings indicate that early-stage diabetes may cause structural and functional impairments in hippocampal CA1 in mice. These abnormalities may parallel alterations in the expression of key BBB tight junction molecules and elevated AGER expression in early DM patients.

Apolipoprotein E deficiency exacerbates blood-brain barrier disruption and hyperglycemia-associated hemorrhagic transformation after ischemic stroke

BACKGROUND

The polymorphism of the apolipoprotein E (ApoE) gene has been implicated in both the susceptibility to neurodegenerative disease and the prognosis of traumatic brain injury (TBI). However, the influence of ApoE on the risk of hemorrhagic transformation (HT) after acute ischemic stroke remains inconclusive. The present study aimed to investigate the potential impact of ApoE deficiency on the risk of hyperglycemia-associated HT and to elucidate the underlying mechanisms.

METHODS

Wild-type (WT) and ApoE knockout (ApoE-/-) mice were injected with 50 % glucose to induce hyperglycemia and subsequently subjected to 90 min of intraluminal middle cerebral artery occlusion (MCAO). The mortality, neurological function, HT incidence and HT grading-score were evaluated at 24 hours after reperfusion. To evaluate the integrity of blood-brain barrier (BBB), the immunoglobulin G (IgG) leakage and the protein expressions of tight junctions (TJs) were detected using immunofluorescent staining and western blotting. Finally, the levels of matrix metalloproteinases (MMP)-2/9, microglial activation and proinflammatory mediators were investigated using immunofluorescent staining and western blotting.

RESULTS

ApoE-/- mice exhibited increased mortality and exacerbated neurological impairment, concomitant with more severe hyperglycemia-associated HT 24 hours post-reperfusion. Meanwhile, ApoE deficiency exacerbated the disruption of BBB, characterized by increased leakage of IgG, aggravated degradation of TJs and microvascular basement membranes. Furthermore, ApoE deficiency further aggravated the upregulation of MMP-2/9 and microglia-triggered neuroinflammation.

CONCLUSIONS

Our findings demonstrate that the absence of ApoE exacerbates neurological impairment and hyperglycemia-associated HT in ischemic stroke mice, which is closely associated with MMP-2/9 signaling and neuroinflammation-mediated disruption of BBB.

Advancements in strategies for overcoming the blood-brain barrier to deliver brain-targeted drugs

The blood-brain barrier is known to consist of a variety of cells and complex inter-cellular junctions that protect the vulnerable brain from neurotoxic compounds; however, it also complicates the pharmacological treatment of central nervous system disorders as most drugs are unable to penetrate the blood-brain barrier on the basis of their own structural properties. This dramatically diminished the therapeutic effect of the drug and compromised its biosafety. In response, a number of drugs are often delivered to brain lesions in invasive ways that bypass the obstruction of the blood-brain barrier, such as subdural administration, intrathecal administration, and convection-enhanced delivery. Nevertheless, these intrusive strategies introduce the risk of brain injury, limiting their clinical application. In recent years, the intensive development of nanomaterials science and the interdisciplinary convergence of medical engineering have brought light to the penetration of the blood-brain barrier for brain-targeted drugs. In this paper, we extensively discuss the limitations of the blood-brain barrier on drug delivery and non-invasive brain-targeted strategies such as nanomedicine and blood-brain barrier disruption. In the meantime, we analyze their strengths and limitations and provide outlooks on the further development of brain-targeted drug delivery systems.

Secretome of brain microvascular endothelial cells promotes endothelial barrier tightness and protects against hypoxia-induced vascular leakage

Cell-based therapeutic strategies have been proposed as an alternative for brain and blood vessels repair after stroke, but their clinical application is hampered by potential adverse effects. We therefore tested the hypothesis that secretome of these cells might be used instead to still focus on cell-based therapeutic strategies. We therefore characterized the composition and the effect of the secretome of brain microvascular endothelial cells (BMECs) on primary in vitro human models of angiogenesis and vascular barrier. Two different secretome batches produced in high scale (scHSP) were analysed by mass spectrometry. Human primary CD34+-derived endothelial cells (CD34+-ECs) were used as well as in vitro models of EC monolayer (CMECs) and blood-brain barrier (BBB). Cells were also exposed to oxygen-glucose deprivation (OGD) conditions and treated with scHSP during reoxygenation. Protein yield and composition of scHSP batches showed good reproducibility. scHSP increased CD34+-EC proliferation, tubulogenesis, and migration. Proteomic analysis of scHSP revealed the presence of growth factors and proteins modulating cell metabolism and inflammatory pathways. scHSP improved the integrity of CMECs, and upregulated the expression of junctional proteins. Such effects were mediated through the activation of the interferon pathway and downregulation of Wnt signalling. Furthermore, OGD altered the permeability of both CMECs and BBB, while scHSP prevented the OGD-induced vascular leakage in both models. These effects were mediated through upregulation of junctional proteins and regulation of MAPK/VEGFR2. Finally, our results highlight the possibility of using secretome from BMECs as a therapeutic alternative to promote brain angiogenesis and to protect from ischemia-induced vascular leakage.

Role and mechanisms of mast cells in brain disorders

Mast cells serve as crucial effector cells within the innate immune system and are predominantly localized in the skin, airways, gastrointestinal tract, urinary and reproductive tracts, as well as in the brain. Under physiological conditions, brain-resident mast cells secrete a diverse array of neuro-regulatory mediators to actively participate in neuroprotection. Meanwhile, as the primary source of molecules causing brain inflammation, mast cells also function as the "first responders" in brain injury. They interact with neuroglial cells and neurons to facilitate the release of numerous inflammatory mediators, proteases, and reactive oxygen species. This process initiates and amplifies immune-inflammatory responses in the brain, thereby contributing to the regulation of neuroinflammation and blood-brain barrier permeability. This article provides a comprehensive overview of the potential mechanisms through which mast cells in the brain may modulate neuroprotection and their pathological implications in various neurological disorders. It is our contention that the inhibition of mast cell activation in brain disorders could represent a novel avenue for therapeutic breakthroughs.

Blood-brain barrier disruption: a culprit of cognitive decline?

Cognitive decline covers a broad spectrum of disorders, not only resulting from brain diseases but also from systemic diseases, which seriously influence the quality of life and life expectancy of patients. As a highly selective anatomical and functional interface between the brain and systemic circulation, the blood-brain barrier (BBB) plays a pivotal role in maintaining brain homeostasis and normal function. The pathogenesis underlying cognitive decline may vary, nevertheless, accumulating evidences support the role of BBB disruption as the most prevalent contributing factor. This may mainly be attributed to inflammation, metabolic dysfunction, cell senescence, oxidative/nitrosative stress and excitotoxicity. However, direct evidence showing that BBB disruption causes cognitive decline is scarce, and interestingly, manipulation of the BBB opening alone may exert beneficial or detrimental neurological effects. A broad overview of the present literature shows a close relationship between BBB disruption and cognitive decline, the risk factors of BBB disruption, as well as the cellular and molecular mechanisms underlying BBB disruption. Additionally, we discussed the possible causes leading to cognitive decline by BBB disruption and potential therapeutic strategies to prevent BBB disruption or enhance BBB repair. This review aims to foster more investigations on early diagnosis, effective therapeutics, and rapid restoration against BBB disruption, which would yield better cognitive outcomes in patients with dysregulated BBB function, although their causative relationship has not yet been completely established.

Small Scale, Big Impact: Nanotechnology-Enhanced Drug Delivery for Brain Diseases

Central nervous system (CNS) diseases, ranging from brain cancers to neurodegenerative disorders like dementia and acute conditions such as strokes, have been heavily burdening healthcare and have a direct impact on patient quality of life. A significant hurdle in developing effective treatments is the presence of the blood-brain barrier (BBB), a highly selective barrier that prevents most drugs from reaching the brain. The tight junctions and adherens junctions between the endothelial cells and various receptors expressed on the cells make the BBB form a nonfenestrated and highly selective structure that is crucial for brain homeostasis but complicates drug delivery. Nanotechnology offers a novel pathway to circumvent this barrier, with nanoparticles engineered to ferry drugs across the BBB, protect drugs from degradation, and deliver medications to the designated area. After years of development, nanoparticle optimization, including sizes, shapes, surface modifications, and targeting ligands, can enable nanomaterials tailored to specific brain drug delivery settings. Moreover, smart nano drug delivery systems can respond to endogenous and exogenous stimuli that control subsequent drug release. Here, we address the importance of the BBB in brain disease treatment, summarize different delivery routes for brain drug delivery, discuss the cutting-edge nanotechnology-based strategies for brain drug delivery, and further offer valuable insights into how these innovations in nanoparticle technology could revolutionize the treatment of CNS diseases, presenting a promising avenue for noninvasive, targeted therapeutic interventions.

Brain-Targeting Emodin Mitigates Ischemic Stroke via Inhibiting AQP4-Mediated Swelling and Neuroinflammation

Failure to achieve target-specific delivery to ischemic brain sites has hampered the clinical efficacy of newly developed therapies for ischemic stroke. Emodin, an active ingredient isolated from traditional Chinese medicine, has been indicated to alleviate ischemic stroke; however, the underlying mechanism remains unclear. In this study, we aimed to achieve brain-targeted delivery of emodin to maximize its therapeutic efficacy and elucidate the mechanisms by which emodin alleviates ischemic stroke. A polyethylene glycol (PEG)/cyclic Arg-Gly-Asp (cRGD)-modified liposome was used to encapsulate emodin. TTC, HE, Nissl staining, and immunofluorescence staining were employed to evaluate the therapeutic efficacy of brain-targeting emodin in MCAO and OGD/R models. Inflammatory cytokine levels were determined using ELISA. Immunoprecipitation, immunoblotting, and RT-qPCR were utilized for clarifying the changes in key downstream signaling. Lentivirus-mediated gene restoration was employed to verify the core effector of emodin for relieving ischemic stroke. Encapsulating emodin in a PEG/cRGD-modified liposome enhanced its accumulation in the infarct region and substantially raised its therapeutic efficacy. Furthermore, we demonstrated that AQP4, the most abundant water transporter subunit expressed in astrocytes, plays a crucial role in mediating the mechanisms by which emodin inhibits astrocyte swelling, neuroinflammatory blood-brain barrier (BBB) breakdown in vivo and in vitro, and brain edema in general. Our study unveiled the critical target of emodin responsible for alleviating ischemic stroke and a localizable drug delivery vehicle in the therapeutic strategy for ischemic stroke and other brain injuries.

3,3',4,5'-Tetramethoxy-trans-stilbene and 3,4',5-trimethoxy-trans-stilbene prevent oxygen-glucose deprivation-induced injury in brain endothelial cell

Blood-brain barrier (BBB) disruption is a major pathophysiological event of ischemic stroke. Brain microvascular endothelial cells are critical to maintain homeostasis between central nervous system and periphery. Resveratrol protects against ischemic stroke. 3,3',4,5'-tetramethoxy-trans-stilbene (3,3',4,5'-TMS) and 3,4',5-trimethoxy-trans-stilbene (3,4',5-TMS) are resveratrol derivatives with addition of methoxy groups, showing better pharmacokinetic performance. We aimed to explore their protective effects and underlying mechanisms. Oxygen-glucose deprivation (OGD) model was applied in bEnd.3 cell line, mouse brain microvascular endothelium to mimic ischemia. The cells were pre-treated with 3,3',4,5'-TMS or 3,4',5-TMS (1 and 5 μM, 24 h) and then subjected to 2-h OGD injury. Cell viability, levels of proinflammatory cytokines and reactive oxygen species (ROS), and protein expressions were measured by molecular assays and fluorescence staining. OGD injury triggered cell death, inflammatory responses, ROS production and nuclear factor-kappa B (NF-κB) signalling pathway. These impairments were remarkably attenuated by the two stilbenes, 3,3',4,5'-TMS and 3,4',5-TMS. They also alleviated endothelial barrier injuries through upregulating the expression of tight junction proteins. Moreover, 3,3',4,5'-TMS and 3,4',5-TMS activated 5' adenosine monophosphate-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS). Overall, 3,3',4,5'-TMS and 3,4',5-TMS exert protective effects against OGD damage through suppressing cell death, inflammatory responses, oxidative stress, as well as BBB disruption on bEnd.3 cells.

Microphysiological Blood-Brain Barrier Systems for Disease Modeling and Drug Development

The blood-brain barrier (BBB) is a highly controlled microenvironment that regulates the interactions between cerebral blood and brain tissue. Due to its selectivity, many therapeutics targeting various neurological disorders are not able to penetrate into brain tissue. Pre-clinical studies using animals and other in vitro platforms have not shown the ability to fully replicate the human BBB leading to the failure of a majority of therapeutics in clinical trials. However, recent innovations in vitro and ex vivo modeling called organs-on-chips have shown the potential to create more accurate disease models for improved drug development. These microfluidic platforms induce physiological stressors on cultured cells and are able to generate more physiologically accurate BBBs compared to previous in vitro models. In this review, different approaches to create BBBs-on-chips are explored alongside their application in modeling various neurological disorders and potential therapeutic efficacy. Additionally, organs-on-chips use in BBB drug delivery studies is discussed, and advances in linking brain organs-on-chips onto multiorgan platforms to mimic organ crosstalk are reviewed.

Atorvastatin-induced intracerebral hemorrhage is inhibited by berberine in zebrafish

Intracerebral hemorrhage (ICH), for which there are currently no effective preventive or treatment methods, has a very high fatality rate. Statins, such as atorvastatin (ATV), are the first-line drugs for regulating blood lipids and treating hyperlipidemia-related cardiovascular diseases. However, ATV-associated ICH has been reported, although its incidence is rare. In this study, we aimed to investigate the protective action and mechanisms of berberine (BBR) against ATV-induced brain hemorrhage. We established an ICH model in zebrafish induced by ATV (2 μM) and demonstrated the effects of BBR (10, 50, and 100 μM) on ICH via protecting the vascular network using hemocyte staining and three transgenic zebrafish. BBR was found to reduce brain inflammation and locomotion injury in ICH-zebrafish. Mechanism research showed that ATV increased the levels of VE-cadherin and occludin proteins but disturbed their localization at the cell membrane by abnormal phosphorylation, which decreased the number of intercellular junctions between vascular endothelial cells (VECs), disrupting the integrity of vascular walls. BBR reversed the effects of ATV by promoting autophagic degradation of phosphorylated VE-cadherin and occludin in ATV-induced VECs examined by co-immunoprecipitation (co-IP). These findings provide crucial insights into understanding the BBR mechanisms involved in the maintenance of vascular integrity and in mitigating adverse reactions to ATV.

Critical role of Slc22a8 in maintaining blood-brain barrier integrity after experimental cerebral ischemia-reperfusion

Blood-brain barrier (BBB) damage significantly affects the prognosis of ischemic stroke patients. This project employed multi-omics analysis to identify key factors regulating BBB disruption during cerebral ischemia-reperfusion. An integrated analysis of three transcriptome sequencing datasets from mouse middle cerebral artery occlusion/reperfusion (MCAO/R) models identified eight downregulated genes in endothelial cells. Additionally, transcriptome analysis of BBB (cortex) and non-BBB (lung) endothelium of E13.5 mice revealed 2,102 upregulated genes potentially associated with BBB integrity. The eight downregulated genes were intersected with the 2,102 BBB-related genes and mapped using single-cell RNA sequencing data, revealing that solute carrier family 22 member 8 (Slc22a8) is specifically expressed in endothelial cells and pericytes and significantly decreases after MCAO/R. This finding was validated in the mouse MCAO/R model at both protein and mRNA levels in this study. External overexpression of Slc22a8 using a lentivirus carrying Tie2 improved Slc22a8 and tight junction protein levels and reduced BBB leakage after MCAO/R, accompanied by Wnt/β-catenin signaling activation. In conclusion, this study suggested that MCAO/R-induced downregulation of Slc22a8 expression may be a crucial mechanism underlying BBB disruption. Interventions that promote Slc22a8 expression or enhance its function hold promise for improving the prognosis of patients with cerebral ischemia.

Cellular and molecular mechanisms of the blood-brain barrier dysfunction in neurodegenerative diseases

BACKGROUND

Maintaining the structural and functional integrity of the blood-brain barrier (BBB) is vital for neuronal equilibrium and optimal brain function. Disruptions to BBB performance are implicated in the pathology of neurodegenerative diseases.

MAIN BODY

Early indicators of multiple neurodegenerative disorders in humans and animal models include impaired BBB stability, regional cerebral blood flow shortfalls, and vascular inflammation associated with BBB dysfunction. Understanding the cellular and molecular mechanisms of BBB dysfunction in brain disorders is crucial for elucidating the sustenance of neural computations under pathological conditions and for developing treatments for these diseases. This paper initially explores the cellular and molecular definition of the BBB, along with the signaling pathways regulating BBB stability, cerebral blood flow, and vascular inflammation. Subsequently, we review current insights into BBB dynamics in Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. The paper concludes by proposing a unified mechanism whereby BBB dysfunction contributes to neurodegenerative disorders, highlights potential BBB-focused therapeutic strategies and targets, and outlines lessons learned and future research directions.

CONCLUSIONS

BBB breakdown significantly impacts the development and progression of neurodegenerative diseases, and unraveling the cellular and molecular mechanisms underlying BBB dysfunction is vital to elucidate how neural computations are sustained under pathological conditions and to devise therapeutic approaches.

Mitochondria-containing extracellular vesicles from mouse vs . human brain endothelial cells for ischemic stroke therapy

Ischemic stroke-induced mitochondrial dysfunction in the blood-brain barrier-forming brain endothelial cells ( BECs ) results in long-term neurological dysfunction post-stroke. We previously data from a pilot study where intravenous administration of human BEC ( hBEC )-derived mitochondria-containing extracellular vesicles ( EVs ) showed a potential efficacy signal in a mouse middle cerebral artery occlusion ( MCAo ) model of stroke. We hypothesized that EVs harvested from donor species homologous to the recipient species ( e.g., mouse) may improve therapeutic efficacy, and therefore, use of mouse BEC ( mBEC )-derived EVs may improve post-stroke outcomes in MCAo mice. We investigated potential differences in the mitochondria transfer of EVs derived from the same species as the recipient cell (mBEC-EVs and recipient mBECs or hBECs-EVs and recipient hBECs) vs . cross-species EVs and recipient cells (mBEC-EVs and recipient hBECs or vice versa ). Our results showed that while both hBEC- and mBEC-EVs transferred EV mitochondria, mBEC-EVs outperformed hBEC-EVs in increasing ATP levels and improved recipient mBEC mitochondrial function via increasing oxygen consumption rates. mBEC-EVs significantly reduced brain infarct volume and neurological deficit scores compared to vehicle-injected MCAo mice. The superior therapeutic efficacy of mBEC-EVs in a mouse MCAo stroke support the continued use of mBEC-EVs to optimize the therapeutic potential of mitochondria-containing EVs in preclinical mouse models.

MyD88 Inhibition Attenuates Cerebral Ischemia-reperfusion Injury by Regulating the Inflammatory Response and Reducing Blood-brain Barrier Damage

Myeloid differentiation primary response gene 88 (MyD88), a downstream molecule directly linked to Toll-like receptor (TLRs) and IL1 receptor, has been implicated in ischemia-reperfusion injury across various organs. However, its role in cerebral ischemia-reperfusion injury (CIRI) remains unclear. Five transient middle cerebral artery occlusion (tMCAO) microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. We screened these datasets for differentially expressed genes (DEGs) using the GSE35338 and GSE58720 datasets and performed weighted gene co-expression network analysis (WGCNA) using the GSE30655, GSE28731, and GSE32529 datasets to identify the core module related to tMCAO. A protein-protein interaction (PPI) network was constructed using the intersecting DEGs and genes in the core module. Finally, we identified Myd88 was the core gene. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) validated that TNFα, IL17, and MyD88 signaling pathways were significantly enriched in tMCAO. Subsequently, we investigated the mechanistic role of MyD88 in the tMCAO model using male C57BL/6 mice. MyD88 expression increased significantly 24 h after reperfusion. After intraperitoneal administration of TJ-M2010-5, a MyD88-specific inhibitor, during reperfusion, the infarction volumes in the mice were ameliorated. TJ-M2010-5 inhibits the activation of microglia and astrocytes. Moreover, it attenuates the upregulation of inflammatory cytokines TNFα, IL17, and MMP9 while preserving the expression level of ZO1 after tMCAO, thereby safeguarding against blood-brain barrier (BBB) disruption. Finally, our findings suggest that MyD88 regulates the IRAK4/IRF5 signaling pathway associated with microglial activation. MyD88 participates in CIRI by regulating the inflammatory response and BBB damage following tMCAO.

Prediction of blood-brain barrier permeability using machine learning approaches based on various molecular representation

The assessment of compound blood-brain barrier (BBB) permeability poses a significant challenge in the discovery of drugs targeting the central nervous system. Conventional experimental approaches to measure BBB permeability are labor-intensive, cost-ineffective, and time-consuming. In this study, we constructed six machine learning classification models by combining various machine learning algorithms and molecular representations. The model based on ExtraTree algorithm and random partitioning strategy obtains the best prediction result, with AUC value of 0.932±0.004 and balanced accuracy (BA) of 0.837±0.010 for the test set. We employed the SHAP method to identify important features associated with BBB permeability. In addition, matched molecular pair (MMP) analysis and representative substructure derivation method were utilized to uncover the transformation rules and distinctive structural features of BBB permeable compounds. The machine learning models proposed in this work can serve as an effective tool for assessing BBB permeability in the drug discovery for central nervous system disease.

Animal models to study cognitive impairment of chronic kidney disease

Mild cognitive impairment (MCI) is common in people with chronic kidney disease (CKD), and its prevalence increases with progressive loss of kidney function. MCI is characterized by a decline in cognitive performance greater than expected for an individual age and education level but with minimal impairment of instrumental activities of daily living. Deterioration can affect one or several cognitive domains (attention, memory, executive functions, language, and perceptual motor or social cognition). Given the increasing prevalence of kidney disease, more and more people with CKD will also develop MCI causing an enormous disease burden for these individuals, their relatives, and society. However, the underlying pathomechanisms are poorly understood, and current therapies mostly aim at supporting patients in their daily lives. This illustrates the urgent need to elucidate the pathogenesis and potential therapeutic targets and test novel therapies in appropriate preclinical models. Here, we will outline the necessary criteria for experimental modeling of cognitive disorders in CKD. We discuss the use of mice, rats, and zebrafish as model systems and present valuable techniques through which kidney function and cognitive impairment can be assessed in this setting. Our objective is to enable researchers to overcome hurdles and accelerate preclinical research aimed at improving the therapy of people with CKD and MCI.

Novel insight into the role of A-kinase anchoring proteins (AKAPs) in ischemic stroke and therapeutic potentials

Ischemic stroke, a devastating disease associated with high mortality and disability worldwide, has emerged as an urgent public health issue. A-kinase anchoring proteins (AKAPs) are a group of signal-organizing molecules that compartmentalize and anchor a wide range of receptors and effector proteins and have a major role in stabilizing mitochondrial function and promoting neurodevelopmental development in the central nervous system (CNS). Growing evidence suggests that dysregulation of AKAPs expression and activity is closely associated with oxidative stress, ion disorder, mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in ischemic stroke. However, the underlying mechanisms remain inadequately understood. This review provides a comprehensive overview of the composition and structure of A-kinase anchoring protein (AKAP) family members, emphasizing their physiological functions in the CNS. We explored in depth the molecular and cellular mechanisms of AKAP complexes in the pathological progression and risk factors of ischemic stroke, including hypertension, hyperglycemia, lipid metabolism disorders, and atrial fibrillation. Herein, we highlight the potential of AKAP complexes as a pharmacological target against ischemic stroke in the hope of inspiring translational research and innovative clinical approaches.

Blood-brain barrier pathology in cerebral small vessel disease

ABSTRACT

Cerebral small vessel disease is a neurological disease that affects the brain microvasculature and which is commonly observed among the elderly. Although at first it was considered innocuous, small vessel disease is nowadays regarded as one of the major vascular causes of dementia. Radiological signs of small vessel disease include small subcortical infarcts, white matter magnetic resonance imaging hyperintensities, lacunes, enlarged perivascular spaces, cerebral microbleeds, and brain atrophy; however, great heterogeneity in clinical symptoms is observed in small vessel disease patients. The pathophysiology of these lesions has been linked to multiple processes, such as hypoperfusion, defective cerebrovascular reactivity, and blood-brain barrier dysfunction. Notably, studies on small vessel disease suggest that blood-brain barrier dysfunction is among the earliest mechanisms in small vessel disease and might contribute to the development of the hallmarks of small vessel disease. Therefore, the purpose of this review is to provide a new foundation in the study of small vessel disease pathology. First, we discuss the main structural domains and functions of the blood-brain barrier. Secondly, we review the most recent evidence on blood-brain barrier dysfunction linked to small vessel disease. Finally, we conclude with a discussion on future perspectives and propose potential treatment targets and interventions.

Crosstalk among Oxidative Stress, Autophagy, and Apoptosis in the Protective Effects of Ginsenoside Rb1 on Brain Microvascular Endothelial Cells: A Mixed Computational and Experimental Study

OBJECTIVE

Brain microvascular endothelial cells (BMECs) were found to shift from their usually inactive state to an active state in ischemic stroke (IS) and cause neuronal damage. Ginsenoside Rb1 (GRb1), a component derived from medicinal plants, is known for its pharmacological benefits in IS, but its protective effects on BMECs have yet to be explored. This study aimed to investigate the potential protective effects of GRb1 on BMECs.

METHODS

An in vitro oxygen-glucose deprivation/reperfusion (OGD/R) model was established to mimic ischemia-reperfusion (I/R) injury. Bulk RNA-sequencing data were analyzed by using the Human Autophagy Database and various bioinformatic tools, including gene set enrichment analysis (GSEA), Gene Ontology (GO) classification and enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, protein-protein interaction network analysis, and molecular docking. Experimental validation was also performed to ensure the reliability of our findings.

RESULTS

Rb1 had a protective effect on BMECs subjected to OGD/R injury. Specifically, GRb1 was found to modulate the interplay between oxidative stress, apoptosis, and autophagy in BMECs. Key targets such as sequestosome 1 (SQSTM1/p62), autophagy related 5 (ATG5), and hypoxia-inducible factor 1-alpha (HIF-1α) were identified, highlighting their potential roles in mediating the protective effects of GRb1 against IS-induced damage.

CONCLUSION

GRbl protects BMECs against OGD/R injury by influencing oxidative stress, apoptosis, and autophagy. The identification of SQSTM1/p62, ATG5, and HIF-1α as promising targets further supports the potential of GRb1 as a therapeutic agent for IS, providing a foundation for future research into its mechanisms and applications in IS treatment.

Quercetin improves the protection of hydroxysafflor yellow a against cerebral ischemic injury by modulating of blood-brain barrier and src-p-gp-mmp-9 signalling

Protection of the structural and functional integrity of the blood-brain barrier (BBB) is crucial for treating ischemic stroke (IS). Hydroxysafflor yellow A (HSYA) and quercetin (Quer), two main active components in the edible and medicinal plant Carthamus tinctorius L., have been reported to exhibit neuroprotective effects. We investigated the anti-IS and BBB-protective properties of HSYA and Quer and the underlying mechanisms. They decreased neurological deficits in middle cerebral artery occlusion (MCAO) mice, while their combination showed better effects. Importantly, HSYA and Quer ameliorated BBB permeability. Their effects on reduction of both EB leakage and infarct volume were similar, which may contribute to improved locomotor activities. Moreover, HSYA and Quer showed protective effects for hCMEC/D3 monolayer against oxygen-glucose deprivation. Src, p-Src, MMP-9, and P-gp were associated with ingredients treatments. Furthermore, molecular docking and molecular dynamics simulations revealed stable and tight binding modes of ingredients with Src and P-gp. The current study supports the potential role of HSYA, Quer, and their combination in the treatment of IS by regulating BBB integrity.

FGF17 protects cerebral ischemia reperfusion-induced blood-brain barrier disruption via FGF receptor 3-mediated PI3K/AKT signaling pathway

Maintaining blood-brain barrier (BBB) integrity is critical components of therapeutic approach for ischemic stroke. Fibroblast growth factor 17 (FGF17), a member of FGF8 superfamily, exhibits the strongest expression throughout the wall of all major arteries during development. However, its molecular action and potential protective role on brain endothelial cells after stroke remains unclear. Here, we observed reduced levels of FGF17 in the serum of patients with ischemic stroke, as well as in the brains of mice subjected to middle cerebral artery occlusion (MCAO) injury and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced brain microvascular endothelial cells (bEnd.3) cells. Moreover, treatment with exogenous recombinant human FGF17 (rhFGF17) decreased infarct volume, improved neurological deficits, reduced Evans Blue leakage and upregulated the expression of tight junctions in MCAO-injured mice. Meanwhile, rhFGF17 increased cell viability, enhanced trans-endothelial electrical resistance, reduced sodium fluorescein leakage, and alleviated reactive oxygen species (ROS) generation in OGD/R-induced bEnd.3 cells. Mechanistically, the treatment with rhFGF17 resulted in nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and upregulation of heme oxygenase-1 (HO-1) expression. Additionally, based on in-vivo and in-vitro research, rhFGF17 exerted protective effects against ischemia/reperfusion (I/R) -induced BBB disruption and endothelial cell apoptosis through the activation of the FGF receptor 3/PI3K/AKT signaling pathway. Overall, our findings indicated that FGF17 may hold promise as a novel therapeutic strategy for ischemic stroke patients.

Beta-caryophyllene in psychiatric and neurological diseases: Role of blood-brain barrier

Beta-caryophyllene is an abundant terpene in cannabis, cinnamon, black pepper, cloves, and citrus fruit, delivering a striking, woody-spicy, like cloves and a sweet fruity aroma. Beta-caryophyllene is a Food and Drug Administration-approved food additive with Generally Recognized as Safe status. Interestingly, several biologic activities have been described for beta-caryophyllene, including anti-inflammatory and analgesic effects, neuroprotection against cerebral ischemia and neuronal injury, protection of neurovascular unit against oxidative damage, glial activation and neuroinflammation and anticonvulsant effects. In this chapter, we intend to review the beneficial effects of beta-caryophyllene in the context of psychiatric and neurological diseases. Also, we will analyze the possibility that the blood-brain-barrier may be a central target underlying the beneficial actions of beta-caryophyllene.

Delta like 4 regulates cerebrovascular development and endothelial integrity via DLL4-NOTCH-CLDN5 pathway and is vulnerable to neonatal hyperoxia

The mechanisms governing brain vascularization during development remain poorly understood. A key regulator of developmental vascularization is delta like 4 (DLL4), a Notch ligand prominently expressed in endothelial cells (EC). Exposure to hyperoxia in premature infants can disrupt the development and functions of cerebral blood vessels and lead to long-term cognitive impairment. However, its role in cerebral vascular development and the impact of postnatal hyperoxia on DLL4 expression in mouse brain EC have not been explored. We determined the DLL4 expression pattern and its downstream signalling gene expression in brain EC using Dll4+/+ and Dll4+/LacZ mice. We also performed in vitro studies using human brain microvascular endothelial cells. Finally, we determined Dll4 and Cldn5 expression in mouse brain EC exposed to postnatal hyperoxia. DLL4 is expressed in various cell types, with EC being the predominant one in immature brains. Moreover, DLL4 deficiency leads to persistent abnormalities in brain microvasculature and increased vascular permeability both in vivo and in vitro. We have identified that DLL4 insufficiency compromises endothelial integrity through the NOTCH-NICD-RBPJ-CLDN5 pathway, resulting in the downregulation of the tight junction protein claudin 5 (CLDN5). Finally, exposure to neonatal hyperoxia reduces DLL4 and CLDN5 expression in developing mouse brain EC. We reveal that DLL4 is indispensable for brain vascular development and maintaining the blood-brain barrier's function and is repressed by neonatal hyperoxia. We speculate that reduced DLL4 signalling in brain EC may contribute to the impaired brain development observed in neonates exposed to hyperoxia. KEY POINTS: The role of delta like 4 (DLL4), a Notch ligand in vascular endothelial cells, in brain vascular development and functions remains unknown. We demonstrate that DLL4 is expressed at a high level during postnatal brain development in immature brains and DLL4 insufficiency leads to abnormal cerebral vasculature and increases vascular permeability both in vivo and in vitro. We identify that DLL4  regulates endothelial integrity through NOTCH-NICD-RBPJ-CLDN5 signalling. Dll4 and Cldn5 expression are decreased in mouse brain endothelial cells exposed to postnatal hyperoxia.

Dexmedetomidine alleviates blood-brain barrier disruption in rats after cerebral ischemia-reperfusion by suppressing JNK and p38 MAPK signaling

Dexmedetomidine displays multiple mechanisms of neuroprotection in ameliorating ischemic brain injury. In this study, we explored the beneficial effects of dexmedetomidine on blood-brain barrier (BBB) integrity and neuroinflammation in cerebral ischemia/reperfusion injury. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 1.5 h and reperfusion for 24 h to establish a rat model of cerebral ischemia/reperfusion injury. Dexmedetomidine (9 􀁐g/kg) was administered to rats 30 min after MCAO through intravenous injection, and SB203580 (a p38 MAPK inhibitor, 200 􀁐g/kg) was injected intraperitoneally 30 min before MCAO. Brain damages were evaluated by 2,3,5-triphenyltetrazolium chloride staining, hematoxylin-eosin staining, Nissl staining, and brain water content assessment. BBB permeability was examined by Evans blue staining. Expression levels of claudin-5, zonula occludens-1, occludin, and matrix metalloproteinase-9 (MMP-9) as well as M1/M2 phenotypes-associated markers were assessed using immunofluorescence, RT-qPCR, Western blotting, and gelatin zymography. Enzyme-linked immunosorbent assay was used to examine inflammatory cytokine levels. We found that dexmedetomidine or SB203580 attenuated infarct volume, brain edema, BBB permeability, and neuroinflammation, and promoted M2 microglial polarization after cerebral ischemia/reperfusion injury. Increased MMP-9 activity by ischemia/reperfusion injury was inhibited by dexmedetomidine or SB203580. Dexmedetomidine inhibited the activation of the ERK, JNK, and p38 MAPK pathways. Moreover, activation of JNK or p38 MAPK reversed the protective effects of dexmedetomidine against ischemic brain injury. Overall, dexmedetomidine ameliorated brain injury by alleviating BBB permeability and promoting M2 polarization in experimental cerebral ischemia/reperfusion injury model by inhibiting the activation of JNK and p38 MAPK pathways.

Acupuncture Extended the Thrombolysis Window by Suppressing Blood-Brain Barrier Disruption and Regulating Autophagy-Apoptosis Balance after Ischemic Stroke

BACKGROUND

Ischemic stroke (IS) is one of the leading causes of death and disability worldwide. The narrow therapeutic window (within 4.5 h) and severe hemorrhagic potential limits therapeutic efficacy of recombinant tissue type plasminogen activator (rt-PA) intravenous thrombolysis for patients. Xingnao Kaiqiao (XNKQ) acupuncture is an integral part of traditional Chinese medicine, specifically designed to address acute ischemic stroke by targeting key acupoints such as Shuigou (GV26) and Neiguan (PC6). In this study, we explored the therapeutic potential of XNKQ acupuncture in extending the time window for thrombolysis and interrogated the molecular mechanisms responsible for this effect.

METHODS

The effect of extending the thrombolysis window by acupuncture was evaluated via TTC staining, neuronal score evaluation, hemorrhagic transformation assay, and H&E staining. RNA sequencing (RNA-seq) technology was performed to identify the therapeutic targets and intervention mechanisms of acupuncture. Evans blue staining and transmission electron microscopy were used to assess blood-brain barrier (BBB) integrity. Immunofluorescence staining and co-immunoprecipitation were performed to evaluate the level of autophagy and apoptosis and validate their interactions with BBB endothelial cells.

RESULTS

Acupuncture alleviated infarction and neurological deficits and extended the thrombolysis window to 6 h. The RNA-seq revealed 16 potential therapeutic predictors for acupuncture intervention, which related to suppressing inflammation and restoring the function of BBB and blood vessels. Furthermore, acupuncture suppressed BBB leakage and preserved tight junction protein expression. The protective effect was associated with regulation of the autophagy-apoptosis balance in BBB endothelial cells. Acupuncture intervention dissociated the Beclin1/Bcl-2 complex, thereby promoting autophagy and reducing apoptosis.

CONCLUSION

XNKQ acupuncture could serve as an adjunctive therapy for rt-PA thrombolysis, aiming to extend the therapeutic time window and mitigate ischemia-reperfusion injury. Acupuncture suppressed BBB disruption by regulating the autophagy-apoptosis balance, which in turn extended the therapeutic window of rt-PA in IS. These findings provide a rationale for further exploration of acupuncture as a complementary candidate co-administered with rt-PA.

The Temporal Relationship between Blood-Brain Barrier Integrity and Microglial Response following Neonatal Hypoxia Ischemia

Blood-brain barrier (BBB) dysfunction and neuroinflammation are key mechanisms of brain injury. We performed a time-course study following neonatal hypoxia-ischemia (HI) to characterize these events. HI brain injury was induced in postnatal day 10 rats by single carotid artery ligation followed by hypoxia (8% oxygen, 90 min). At 6, 12, 24, and 72 h (h) post-HI, brains were collected to assess neuropathology and BBB dysfunction. A significant breakdown of the BBB was observed in the HI injury group compared to the sham group from 6 h in the cortex and hippocampus (p < 0.001), including a significant increase in albumin extravasation (p < 0.0033) and decrease in basal lamina integrity and tight-junction proteins. There was a decrease in resting microglia (p < 0.0001) transitioning to an intermediate state from as early as 6 h post-HI, with the intermediate microglia peaking at 12 h (p < 0.0001), which significantly correlated to the peak of microbleeds. Neonatal HI insult leads to significant brain injury over the first 72 h that is mediated by BBB disruption within 6 h and a transitioning state of the resident microglia. Key BBB events coincide with the appearance of the intermediate microglial state and this relationship warrants further research and may be a key target for therapeutic intervention.

Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives

Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.

MicroRNA Regulatory Pattern in Diabetic Mouse Cortex at Different Stages Following Ischemic Stroke

After ischemic stroke, microRNAs (miRNAs) participate in various processes, including immune responses, inflammation, and angiogenesis. Diabetes is a key factor increasing the risk of ischemic stroke; however, the regulatory pattern of miRNAs at different stages of diabetic stroke remains unclear. This study comprehensively analyzed the miRNA expression profiles in diabetic mice at 1, 3, and 7 days post-reperfusion following the middle cerebral artery occlusion (MCAO). We identified differentially expressed (DE) miRNAs in diabetic stroke and found significant dysregulation of some novel miRNAs (novel_mir310, novel_mir89, and novel_mir396) post-stroke. These DEmiRNAs were involved in apoptosis and the formation of tight junctions. Finally, we identified three groups of time-dependent DE miRNAs (miR-6240, miR-135b-3p, and miR-672-5p). These have the potential to serve as biomarkers of diabetic stroke. These findings provide a new perspective for future research, emphasizing the dynamic changes in miRNA expression after diabetic stroke and offering potential candidates as biomarkers for future clinical applications.

Clarifying the mechanism of apigenin against blood-brain barrier disruption in ischemic stroke using systems pharmacology

Currently, recombinant tissue plasminogen activator (rtPA) is an effective therapy for ischemic stroke (IS). However, blood-brain barrier (BBB) disruption is a serious side effect of rtPA therapy and may lead to patients' death. The natural polyphenol apigenin has a good therapeutic effect on IS. Apigenin has potential BBB protection, but the mechanism by which it protects the BBB integrity is not clear. In this study, we used network pharmacology, bioinformatics, molecular docking and molecular dynamics simulation to reveal the mechanisms by which apigenin protects the BBB. Among the 146 targets of apigenin for the treatment of IS, 20 proteins were identified as core targets (e.g., MMP-9, TLR4, STAT3). Apigenin protects BBB integrity by inhibiting the activity of MMPs through anti-inflammation and anti-oxidative stress. These mechanisms included JAK/STAT, the toll-like receptor signaling pathway, and Nitrogen metabolism signaling pathways. The findings of this study contribute to a more comprehensive understanding of the mechanism of apigenin in the treatment of BBB disruption and provide ideas for the development of drugs to treat IS.

Exposure to different surface-modified polystyrene nanoparticles caused anxiety, depression, and social deficit in mice via damaging mitochondria in neurons

Nanoplastics (NPs) are unavoidable hazardous materials that result from the human production and use of plastics. While there is evidence that NPs can bioaccumulate in the brain, no enough research regarding the pathways by which NPs reach the brain was conducted, and it is also urgently needed to evaluate the health threat to the nervous system. Here, we observed accumulation of polystyrene nanoplastics (PS-NPs) with different surface modifications (PS, PS-COOH, and PS-NH2) in mouse brains. Further studies showed that PS-NPs disrupted the tight junctions between endothelial cells and transport into endothelial cells via the endocytosis and macropinocytosis pathways. Additionally, NPs exposure induced a series of alternations in behavioral tests, including anxiety- and depression-like changes and impaired social interaction performance. Further results identified that NPs could be internalized into neurons and localized in the mitochondria, bringing about mitochondrial dysfunction and a concurrent decline of ATP production, which might be associated with abnormal animal behaviors. The findings provide novel insights into the neurotoxicity of NPs and provide a basis for the formulation of policy on plastic production and usage by relevant government agencies.

A New Perspective in the Treatment of Ischemic Stroke: Ferroptosis

Ischemic stroke is a common neurological disease. Currently, there are no Food and Drug Administration-approved drugs that can maximize the improvement in ischemic stroke-induced nerve damage. Hence, treating ischemic stroke remains a clinical challenge. Ferroptosis has been increasingly studied in recent years, and it is closely related to the pathophysiological process of ischemic stroke. Iron overload, reactive oxygen species accumulation, lipid peroxidation, and glutamate accumulation associated with ferroptosis are all present in ischemic stroke. This article focuses on describing the relationship between ferroptosis and ischemic stroke and summarizes the relevant substances that ameliorate ischemic stroke-induced neurological damage by inhibiting ferroptosis. Finally, the problems in the treatment of ischemic stroke targeting ferroptosis are discussed, hoping to provide a new direction for its treatment.

Lifibrate attenuates blood-brain barrier damage following ischemic stroke via the MLCK/p-MLC/ZO-1 axis

Dysfunction of tight junction proteins-associated damage to the blood-brain barrier (BBB) plays an important role in the pathogenesis of ischemic stroke. Lifibrate, an inhibitor of cholinephosphotransferase (CPT), has been used as an agent for serum lipid lowering. However, the protective effects of Lifibrate in ischemic stroke and the underlying mechanism have not been clearly elucidated. Here, we employed an in vivo mice model of MCAO and an OGD/R model in vitro. In the mice models, neurological deficit scores and infarct volume were assessed. Evans Blue solution was used to detect the BBB permeability. The TEER was examined to determine brain endothelial monolayer permeability. Here, we found that Lifibrate improved neurological dysfunction in stroke. Additionally, increased BBB permeability during stroke was significantly ameliorated by Lifibrate. Correspondingly, the reduced expression of the tight junction protein ZO-1 was restored by Lifibrate at both the mRNA and protein levels. Using an in vitro model, we found that Lifibrate ameliorated OGD/R-induced injury in human bEnd.3 brain microvascular endothelial cells by increasing cell viability but reducing the release of LDH. Importantly, Lifibrate suppressed the increase in endothelial monolayer permeability and the reduction in TEER induced by OGD/R via the rescue of ZO-1 expression. Mechanistically, Lifibrate blocked activation of the MLCK/ p-MLC signaling pathway in OGD/R-stimulated bEnd.3 cells. In contrast, overexpression of MLCK abolished the protective effects of Lifibrate in endothelial monolayer permeability, TEER, as well as the expression of ZO-1. Our results provide a basis for further investigation into the neuroprotective mechanism of Lifibrate during stroke.

Activation of endothelial TRPM2 exacerbates blood-brain barrier degradation in ischemic stroke

AIMS

Damage of the blood-brain barrier (BBB) is a hallmark of brain injury during the early stages of ischemic stroke. The subsequent endothelial hyperpermeability drives the initial pathological changes and aggravates neuronal death. Transient receptor potential melastatin 2 (TRPM2) is a Ca2+-permeable nonselective cation channel activated by oxidative stress. However, whether TRPM2 is involved in BBB degradation during ischemic stroke remains unknown. We aimed to investigate the role of TRPM2 in BBB degradation during ischemic stroke and the underlying molecular mechanisms.

METHODS AND RESULTS

Specific deletion of Trpm2 in endothelial cells using Cdh5 Cre produces a potent protective effect against brain injury in mice subjected to middle cerebral artery occlusion (MCAO), which is characterized by reduced infarction size, mitigated plasma extravasation, suppressed immune cell invasion, and inhibited oxidative stress. In vitro experiments using cultured cerebral endothelial cells (CECs) demonstrated that either Trpm2 deletion or inhibition of TRPM2 activation attenuates oxidative stress, Ca2+ overload, and endothelial hyperpermeability induced by oxygen-glucose deprivation (OGD) and CD36 ligand thrombospondin-1 (TSP1). In transfected HEK293T cells, OGD and TSP1 activate TRPM2 in a CD36-dependent manner. Noticeably, in cultured CECs, deleting Trpm2 or inhibiting TRPM2 activation also suppresses the activation of CD36 and cellular dysfunction induced by OGD or TSP1.

CONCLUSIONS

In conclusion, our data reveal a novel molecular mechanism in which TRPM2 and CD36 promote the activation of each other, which exacerbates endothelial dysfunction during ischemic stroke. Our study suggests that TRPM2 in endothelial cells is a promising target for developing more effective and safer therapies for ischemic stroke.

Inhibition of EphA4 reduces vasogenic edema after experimental stroke in mice by protecting the blood-brain barrier integrity

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.

Surface-Tailored Nanoplatform for the Diagnosis and Management of Stroke: Current Strategies and Future Outlook

Stroke accounts for one of the top leading reasons for neurological mortality and morbidity around the globe. Both ischemic and hemorrhagic strokes lead to local hypoxia and are brought about by the occlusion or rupturing of the blood vessels. The events taking place after the onset of a stroke include membrane ion pump failure, calcium and glutamate-mediated excitotoxicity, increased ROS production causing DNA damage, mitochondrial dysfunction, oxidative stress, development of brain edema, and microvascular dysfunction. To date, tissue plasminogen activator (tPA) therapy and mechanical removal of blood clots are the only clinically available stroke therapies, approved by Food and Drug Administration (FDA). But because of the narrow therapeutic window of around 4.5 h for tPA therapy and complications like systemic bleeding and anaphylaxis, more clinical trials are ongoing in the same field. Therefore, using nanocarriers with diverse physicochemical properties is a promising strategy in treating and diagnosing stroke as they can efficiently bypass the tight blood-brain barrier (BBB) through mechanisms like receptor-mediated transcytosis and help achieve controlled and targeted drug delivery. In this review, we will mainly focus on the pathophysiology of stroke, BBB alterations following stroke, strategies to target BBB for stroke therapies, different types of nanocarriers currently being used for therapeutic intervention of stroke, and biomarkers as well as imaging techniques used for the detection and diagnosis of stroke.

Knockdown of FOXO4 protects against OGD/R‑induced cerebral microvascular endothelial cell injury and regulates the AMPK/Nrf2/HO‑1 pathway through transcriptional activation of CTRP6

Cerebral ischemia is a type of cerebrovascular disease with high disability and mortality rates. The expression of forkhead box protein O4 (FOXO4) in the brain is increased following traumatic brain injury. To the best of our knowledge, however, the role of FOXO4 as well as its mechanism in cerebral ischemia has not been reported so far. For the establishment of an in vitro cellular injury model, human brain microvascular endothelial HCMEC/D3 cells were induced by oxygen-glucose deprivation/reoxygenation (OGD/R). mRNA and protein expressions of FOXO4 and C1q/tumor necrosis factor-related protein 6 (CTRP6) in OGD/R-induced HCMEC/D3 cells were detected by reverse transcription-quantitative (RT-q)PCR and western blotting. The transfection efficacy of small interfering (si)- and overexpression (Ov)-FOXO4 and si-CTRP6 was assessed using RT-qPCR and western blotting. Cell Counting Kit-8 and TUNEL assay were used to assess viability and apoptosis of HCMEC/D3 cells induced by OGD/R, respectively. A FITC-Dextran assay kit was applied to determine endothelial permeability and immunofluorescence assay was used for the measurement of the tight junction protein zonula occludens-1. The levels of oxidative stress markers and inflammatory cytokines were assessed with corresponding assay kits. The binding sites of transcription factor, FOXO4 and CTRP6 promoter were predicted using HDOCK SERVER. Luciferase reporter assay was used to detect the activity of the CTRP6 promoter while chromatin immunoprecipitation assay was used to evaluate the binding ability of the FOXO4 and CTRP6 promoter. Western blotting was used for the detection of apoptosis- and AMPK/Nrf2/heme oxygenase-1 (HO-1) pathway-associated proteins, along with tight junction proteins. The expression of FOXO4 was increased in OGD/R-induced HCMEC/D3 cells. After interfering with FOXO4 in cells, the viability of the OGD/R-induced HCMEC/D3 cells was increased while apoptosis was decreased. Furthermore, FOXO4 interference improved cellular barrier dysfunction but inhibited oxidative stress and the inflammatory response in HCMEC/D3 cells induced by OGD/R. FOXO4 knockdown regulated CTRP6 transcription in HCMEC/D3 cells. Knockdown of FOXO4 regulated expression of CTRP6 and protected OGD/R-induced HCMEC/D3 cell injury via the AMPK/Nrf2/HO-1 pathway. The present study indicated that FOXO4 knockdown activated CTRP6 to protect against cerebral microvascular endothelial cell injury induced by OGD/R via the AMPK/Nrf2/HO-1 pathway.

Sex differences in physiological response to increased neuronal excitability in a knockin mouse model of pediatric epilepsy

BACKGROUND

Epilepsy is a common neurological disease; however, few if any of the currently marketed antiseizure medications prevent or cure epilepsy. Discovery of pathological processes in the early stages of epileptogenesis has been challenging given the common use of preclinical models that induce seizures in physiologically normal animals. Moreover, despite known sex dimorphism in neurological diseases, females are rarely included in preclinical epilepsy models.

METHODS

We characterized sex differences in mice carrying a pathogenic knockin variant (p.N1768D) in the Scn8a gene that causes spontaneous tonic-clonic seizures (TCs) at ∼3 months of age and found that heterozygous females are more resilient than males in mortality and morbidity. To investigate the cellular mechanisms that underlie female resilience, we utilized blood-brain barrier (BBB) and hippocampal transcriptomic analyses in heterozygous mice before seizure onset (pre-TC) and in mice that experienced ∼20 TCs (post-TC).

RESULTS

In the pre-TC latent phase, both sexes exhibited leaky BBB; however, patterns of gene expression were sexually dimorphic. Females exhibited enhanced oxidative phosphorylation and protein biogenesis, while males activated gliosis and CREB signaling. After seizure onset (chronic phase), females exhibited a metabolic switch to lipid metabolism, while males exhibited increased gliosis and BBB dysfunction and a strong activation of neuroinflammatory pathways.

CONCLUSION

The results underscore the central role of oxidative stress and BBB permeability in the early stages of epileptogenesis, as well as sex dimorphism in response to increasing neuronal hyperexcitability. Our results also highlight the need to include both sexes in preclinical studies to effectively translate results of drug efficacy studies.