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The central nervous system (CNS) requires specialized blood vessels to support neural function within specific microenvironments. During neurovascular development, endothelial Wnt/β-catenin signaling is required for BBB development within the brain parenchyma, whereas fenestrated blood vessels that lack BBB properties do not require Wnt/β-catenin signaling. Here, we used zebrafish to further characterize this phenotypic heterogeneity of the CNS vasculature. Using transgenic reporters of Wnt/β-catenin transcriptional activity, we found an inverse correlation between activated Wnt/β-catenin signaling in endothelial cells (ECs) versus non-ECs within these distinct microenvironments. Our results indicated that the level of Wnt/β-catenin signaling in non-ECs may regulate Wnt/β-catenin activity in adjacent ECs. To further test this concept, we generated a transgenic Tet-On inducible system to drive constitutively active β-catenin expression in neural progenitor cells (NPCs). We found that dose-dependent activation of Wnt/β-catenin in NPCs caused severe deficiency in CNS angiogenesis and BBB development. Additionally, we discovered a significant increase in the proliferation of microglia and infiltration of peripheral neutrophils indicative of a stereotypical neuroinflammatory response. In conclusion, our results demonstrate the importance of proper Wnt/β-catenin signaling within specific CNS microenvironments and highlights the potentially deleterious consequences of aberrant Wnt activation. [ABSTRACT FROM AUTHOR]

Introduction: Ischemic stroke is a devastating neurovascular condition that occurs when cerebral tissue fails to receive an adequate supply of oxygen. Despite being a leading cause of death and disability worldwide, therapeutic interventions are currently limited. Polyamidoamine (PAMAM) dendrimers are nanomolecules commonly used in biomedical applications due to their ability to encapsulate small-molecules and improve their pharmacokinetic properties. Curcumin is known to have anti-inflammatory and antioxidant effects yet suffers from poor solubility and bioavailability. The purpose of this study is to investigate the efficacy of curcumin encapsulated in PAMAM dendrimers as a potential therapeutic treatment for ischemic stroke by studying post-stroke lesion size, astrocyte reactivity, and functional recovery in a rat model of cerebral ischemia. Methods: Forty-eight male and female Sprague-Dawley rats (280–380 g) underwent either a 90-min middle cerebral artery occlusion (MCAo) or sham surgery before receiving one of four treatments: (1) Hanks' balanced salt solution (HBSS) control, (2) empty dendrimer control, (3) curcumin control, or (4) curcumin encapsulated in PAMAM dendrimer. Neurobehavioral outcomes were evaluated at 1-, 3-, 5-, and 7-day post-surgery, after which animals were euthanized on day 8 to assess infarct volume and GFAP immunoreactivity. Results: Animals that received formulations containing dendrimers (curcumin encapsulated in dendrimers or empty dendrimers) demonstrated significantly lower levels of GFAP immunoreactivity and improved functional recovery, including weight and neurobehavioral scores, compared to the formulations that did not contain dendrimers (curcumin and HBSS control). Additionally, the dendrimer-curcumin treatment group exhibited a significantly improved paw laterality index over the course of the study compared with the other three treatment groups. Conclusion: Although the post-stroke administration of curcumin encapsulated in PAMAM dendrimers modulates the astrocytic response and promotes functional recovery following ischemic stroke in rats, its therapeutic benefits may be driven by PAMAM dendrimers as the empty dendrimer treatment group also showed significant improvements post-stroke. Further investigation regarding PAMAM dendrimers in treating neuroinflammatory conditions remains warranted. [ABSTRACT FROM AUTHOR]

Brain-on-a-chip is an emerging field involving microfluidic devices capable of mimicking the structure and function of the human brain. Existing research often focuses on single barriers, such as the blood–brain barrier or blood–cerebrospinal fluid barrier (BCSFB). However, the brain has both barriers working together, and mimicking this dual system is crucial for better understanding of brain (patho)physiology. In this work, we present a four-channel microfluidic chip model that incorporates both the BBB and BCSFB, to reproduce physiologically correct architecture. Using computer simulations, we demonstrate that this model can mimic both healthy and diseased states by adjusting the shear stress experienced by the barriers, which is a key factor in their function. These findings offer valuable insights for designing future brain-on-a-chip devices with improved accuracy. This improved technology could contribute to wider advancements in tissue engineering and the study of brain function and diseases. [ABSTRACT FROM AUTHOR]

An ischemic cerebral stroke results from the interruption of blood flow to the brain, triggering rapid and complex cascades of excitotoxicity, oxidative stress, and inflammation. Current reperfusion therapies, including intravenous thrombolysis and mechanical thrombectomy, cause further brain injury due to reperfusion-induced cytotoxicity. To date, novel cytoprotective therapies that could address these challenges have yet to be developed, likely due to the limitations of targeting a single pathologic mechanism. To address these unmet clinical needs, we investigated a synthetic verbenone derivative, SP-8356, as a potential multi-target cytoprotective agent for acute ischemic strokes. In transient middle cerebral artery occlusion (MCAO) rats, SP-8356 significantly reduced brain infarct and edema volumes while improving acute neurological deficits in a dose-dependent manner. Furthermore, SP-8356 improved long-term outcomes, particularly by reducing mortality. These potent cytoprotective effects of SP-8356 were achieved by suppressing the excessive production of free radicals and pro-inflammatory cytokines, reducing the infiltration of inflammatory cells, and mitigating increases in blood–brain barrier permeability. Additional research is needed to determine whether co-administration of SP-8356 can extend the therapeutic time window of reperfusion therapies by mitigating ischemia/reperfusion injury. [ABSTRACT FROM AUTHOR]

Abstract Brain-on-a-chip is an emerging field involving microfluidic devices capable of mimicking the structure and function of the human brain. Existing research often focuses on single barriers, such as the blood–brain barrier or blood–cerebrospinal fluid barrier (BCSFB). However, the brain has both barriers working together, and mimicking this dual system is crucial for better understanding of brain (patho)physiology. In this work, we present a four-channel microfluidic chip model that incorporates both the BBB and BCSFB, to reproduce physiologically correct architecture. Using computer simulations, we demonstrate that this model can mimic both healthy and diseased states by adjusting the shear stress experienced by the barriers, which is a key factor in their function. These findings offer valuable insights for designing future brain-on-a-chip devices with improved accuracy. This improved technology could contribute to wider advancements in tissue engineering and the study of brain function and diseases.

Abstract Background Status epilepticus (SE) is a common severe neurological emergency. Cerebral edema caused by SE is unavoidable and may exacerbate epilepsy. Recent studies have identified cerebrospinal fluid (CSF) as a crucial fluid source of initial cerebral edema following ischemic stroke and cardiac arrest. Moreover, synchronized neuronal firings drive CSF influx into interstitial fluid (ISF). Parenchymal border macrophages (PBMs) have been found to play a role in regulating CSF flow dynamics. However, the involvement of CSF and PBMs in cerebral edema during SE remains unclear. Here, we investigated the fluid source of cerebral edema in the initial phase of SE with the role of PBMs involved. Methods Lithium chloride-pilocarpine was used to induce SE in C57BL/6 J mice. Electroencephalogram (EEG) was acquired to assess changes in relative EEG power pre- and post-seizure onset. Apparent diffusion coefficient (ADC) maps reconstructed from diffusion-weighted imaging (DWI) were utilized to evaluate cytotoxic edema. Blood–brain barrier (BBB) permeability was examined using sodium fluorescein (NaFl). CSF tracer influx into the brain was assessed by transcranial imaging and brain slices. PBMs were depleted using clodronate liposomes. Immunohistochemistry was used to evaluate PBM depletion, severity of vasogenic edema, inflammation, and neuronal damage. Results During the initial stage of SE, relative EEG power sharply increased and ADC values significantly decreased. Concurrently, CSF tracer influx into the cortex significantly elevated, though NaFl leakage from blood to brain parenchyma did not evidently alter. Following depletion of PBM, CSF influx declined but AQP4 expression and polarization remained unaffected. Post-PBM depletion, there was no significant alteration in relative EEG power, yet CSF influx decreased substantially during the initial stage of SE. The degree of ADC decline lessened, IgG extravasation after SE decreased, activated microglia and proliferating astrocytes count fell, and neuronal damage post-SE alleviated. Conclusions CSF appeared to contribute to cerebral edema in SE. Depletion of PBM alleviated cytotoxic edema in the initial phase of SE, and subsequent vasogenic edema, inflammatory response and neurological damage were reduced. These findings may provide potential novel strategies for treating cerebral edema following SE.

Central nervous system diseases negatively affect patients and society. Providing successful noninvasive treatments for these diseases is challenging because of the presence of the blood–brain barrier. While protecting the brain’s homeostasis, the barrier limits the passage of almost all large-molecule drugs and most small-molecule drugs. A noninvasive method, nose-to-brain delivery (N2B delivery) has been proposed to overcome this challenge. By exploiting the direct anatomical interaction between the nose and the brain, the drugs can reach the target, the brain. Moreover, the drugs can be encapsulated into various drug delivery systems to enhance physicochemical characteristics and targeting success. Many preclinical data show that this strategy can effectively deliver biopharmaceuticals to the brain. Therefore, this review focuses on N2B delivery while giving examples of different drug delivery systems suitable for the applications. In addition, we emphasize the importance of the effective delivery of monoclonal antibodies and RNA and stress the recent literature tackling this challenge. While giving examples of nanotechnological approaches for the effective delivery of small or large molecules from the current literature, we highlight the preclinical studies and their results to prove the strategies’ success and limitations.

Abstract Background The most crucial area to focus on when thinking of novel pathways for drug delivery into the CNS is the blood brain barrier (BBB). A number of nanoparticulate formulations have been shown in earlier research to target receptors at the BBB and transport therapeutics into the CNS. However, no mechanism for CNS entrance and movement throughout the CNS parenchyma has been proposed yet. Here, the truncated mini low-density lipoprotein receptor-related protein 1 mLRP1_DIV* was presented as blood to brain transport carrier, exemplified by antibodies and immunoliposomes using a systematic approach to screen the receptor and its ligands’ route across endothelial cells in vitro. Methods The use of mLRP1_DIV* as liposomal carrier into the CNS was validated based on internalization and transport assays across an in vitro model of the BBB using hcMEC/D3 and bEnd.3 cells. Trafficking routes of mLRP1_DIV* and corresponding cargo across endothelial cells were analyzed using immunofluorescence. Modulation of γ-secretase activity by immunoliposomes loaded with the γ-secretase modulator BB25 was investigated in co-cultures of bEnd.3 mLRP1_DIV* cells and CHO cells overexpressing human amyloid precursor protein (APP) and presenilin 1 (PSEN1). Results We showed that while expressed in vitro, mLRP1_DIV* transports both, antibodies and functionalized immunoliposomes from luminal to basolateral side across an in vitro model of the BBB, followed by their mLRP1_DIV* dependent release of the cargo. Importantly, functionalized liposomes loaded with the γ-secretase modulator BB25 were demonstrated to effectively reduce toxic Aß42 peptide levels after mLRP1_DIV* mediated transport across a co-cultured endothelial monolayer. Conclusion Together, the data strongly suggest mLRP1_DIV* as a promising tool for drug delivery into the CNS, as it allows a straight transport of cargo from luminal to abluminal side across an endothelial monolayer and it’s release into brain parenchyma in vitro, where it exhibits its intended therapeutic effect.

The mechanisms underlying pathological changes in the central nervous system (CNS) following Coxsackievirus A16 (CV-A16) infection have not yet been elucidated. IFN-γ-inducible protein-10 (IP-10) is often used as a predictive factor to monitor early virus infection. It has also been reported that IP-10 plays a pivotal role in neuroinflammation. In this study, we aimed to explore the role of IP-10 in the neuropathogenesis of CV-A16 infection. We observed that the level of IP-10, as well as the TLR3-TRIF-TRAF3-TBK1-NF-κB and RIG-I/MDA5-MAVS-TRAFS-TBK1-NF-κB pathways, which are the upstream of IP-10, were significantly elevated during the course of CV-A16 infection. This increase was accompanied by an increase in a series of inflammatory cytokines at different time-points during CV-A16 infection. To determine whether IP-10 influences BBB integrity, we examined junctional complexes. Our results revealed that the expression levels of Claudin5, Occludin, ZO-1 and VE-Cadherin were notably decreased in CV-A16-infected HUVECs, but these indicators were restored in CV-A16-infected HUVECs with Eldelumab treatment. Nevertheless, IP-10 is only a chemokine that primarily traffics CXCR3-positive immune cells to inflammatory sites or promotes the production of inflammatory cytokines. Therefore, the interactions between IP-10 and inflammatory cytokines were evaluated. Our data revealed that IP-10 mediated the production of TNF-α, which was also observed to change the junctional complexes. Moreover, in a suckling mouse model, IP-10 and TNF-α treatments exacerbated clinical symptoms, mortality and pathological changes in the brain of CV-A16-infected mice, but Anti-IP-10 and Anti-TNF-α treatments alleviated these changes. Our data also revealed that IP-10 may be detected early in CV-A16 infection, whereas TNF-α was detected late in CV-A16 infection, and the production of TNF-α was also found to be positively correlated with IP-10. In addition, IP-10 and TNF-α were observed to reduce junctional complexes and enhance virus entry into the CNS. Taken together, this study provides the first evidence that CV-A16 activates the IP-10/TNF-α regulatory axis to cause BBB damage and accelerate the formation of neuroinflammation in infected hosts, which not only provides a new understanding of the neuropathogenesis caused by CV-A16, but also offers a promising target for the development of CV-A16 antiviral drugs. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV-1) remains a persistent global health crisis. Even while successfully virologically suppressed, people with HIV (PWH) experience a higher risk for inflammatory disorders such as HIV-associated neurocognitive disorder (HAND). Tobacco use puts PWH at higher risk for neurocognitive symptoms resulting from HIV-associated neuroinflammation. The NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome has been implicated as a driver of HIV-associated inflammation, including HAND. Nicotine, the psychoactive component of tobacco smoke, has also been shown to signal through the NLRP3 inflammasome and modulate inflammatory signaling in the CNS. Here, we explore the impacts of nicotine and tobacco on the complex neurobiology of HAND, including effects on cognition, inflammation, viral latency, and blood-brain barrier integrity. We outline nicotine's role in the establishment of active and latent infection in the brain and posit the NLRP3 inflammasome as a common pathway by which HIV-1 and nicotine promote neuroinflammation in PWH. [ABSTRACT FROM AUTHOR]

Increased endothelial permeability plays an important role in blood-brain barrier (BBB) dysfunction and is implicated in neuronal injury in many diseased conditions. BBB disruption is primarily determined by dysfunction of endothelial cell-cell junctions. Deprivation of oxygen supply or hypoxia, a common feature of a variety of human diseases, is a major risk factor for BBB disruption. The molecular regulatory mechanisms of hypoxiainduced BBB dysfunction remain incompletely understood. The mitochondrial enzyme, arginase type II (Arg-II), has been shown to promote endothelial dysfunction. However, its role in hypoxia-induced BBB dysfunction has not been explored. In the C57BL/6J mouse model, hypoxia (8% O2, 24 hours) augments vascular Arg-II in the hippocampus, decreases cell-cell junction protein levels of Zonula occludens-1 (ZO-1), occludin, and CD31 in endothelial cells, increases BBB leakage in the brain in old mice (20 to 24 months) but not in young animals (3 to 6 months). These effects of hypoxia in aging are suppressed in arg-ii-/- mice. Moreover, the age-associated vulnerability of endothelial integrity to hypoxia is demonstrated in senescent human brain microvascular endothelial cell (hCMEC/D3) culture model. Further results in the cell culture model show that hypoxia augments Arg-II, decreases ZO-1 and occludin levels, and increases endothelial permeability, which is prevented by arg-ii gene silencing or by inhibition of mitochondrial reactive oxygen species (mtROS) production. Our study demonstrates an essential role of Arg-II in increased endothelial permeability and BBB dysfunction by promoting mtROS generation, resulting in decreased endothelial cell-cell junction protein levels under hypoxic conditions particularly in aging. [ABSTRACT FROM AUTHOR]

Background: The blood–brain barrier (BBB) strictly regulates the penetration of substances into the brain, which, although important for maintaining brain homeostasis, may delay drug development because of the difficulties in predicting pharmacokinetics/pharmacodynamics (PKPD), toxicokinetics/toxicodynamics (TKTD), toxicity, safety, and efficacy in the central nervous system (CNS). Moreover, BBB functional proteins show species differences; therefore, humanized in vitro BBB models are urgently needed to improve the predictability of preclinical studies. Recently, international trends in the 3Rs in animal experiments and the approval of the FDA Modernization Act 2.0 have accelerated the application of microphysiological systems (MPSs) in preclinical studies, and in vitro BBB models have become synonymous with BBB–MPSs. Recently, we developed an industrialized humanized BBB–MPS, BBB–NET. In our previous report, we reproduced transferrin receptor (TfR)–mediated transcytosis with high efficiency and robustness, using hydrogels including fibrin and collagen I microfibers (CMFs). Methods: We investigated how adding CMFs to the fibrin gel benefits BBB-NETs. Results: We showed that CMFs accelerate capillary network formation and maturation by promoting astrocyte (AC) survival, and clarified that integrin β1 is involved in the mechanism of CMFs. Conclusions: Our data suggest that the quality control (QC) of CMFs is important for ensuring the stable production of BBB–NETs. [ABSTRACT FROM AUTHOR]

In recent years, various drug delivery systems circumventing the blood–brain barrier have emerged for treating brain tumors. This study aimed to improve the efficacy of brain tumor treatment in boron neutron capture therapy (BNCT) using cerebrospinal fluid (CSF) circulation to deliver boronophenylalanine (BPA) to targeted tumors. Previous experiments have demonstrated that boron accumulation in the brain cells of normal rats remains comparable to that after intravenous (IV) administration, despite BPA being administered via CSF at significantly lower doses (approximately 1/90 of IV doses). Based on these findings, BNCT was conducted on glioma model rats at the Kyoto University Research Reactor Institute (KUR), with BPA administered via CSF. This method involved implanting C6 cells into the brains of 8-week-old Wistar rats, followed by administering BPA and neutron irradiation after a 10-day period. In this study, the rats were divided into four groups: one receiving CSF administration, another receiving IV administration, and two control groups without BPA administration, with one subjected to neutron irradiation and the other not. In the CSF administration group, BPA was infused from the cisterna magna at 8 mg/kg/h for 2 h, while in the IV administration group, BPA was intravenously administered at 350 mg/kg via the tail vein over 1.5 h. Thermal neutron irradiation (5 MW) for 20 min, with an average fluence of 3.8 × 1012/cm2, was conducted at KUR's heavy water neutron irradiation facility. Subsequently, all of the rats were monitored under identical conditions for 7 days, with pre- and post-irradiation tumor size assessed through MRI and pathological examination. The results indicate a remarkable therapeutic efficacy in both BPA-administered groups (CSF and IV). Notably, the rats treated with CSF administration exhibited diminished BPA accumulation in normal tissue compared to those treated with IV administration, alongside maintaining excellent overall health. Thus, CSF-based BPA administration holds promise as a novel drug delivery mechanism in BNCT. [ABSTRACT FROM AUTHOR]

Background: The most crucial area to focus on when thinking of novel pathways for drug delivery into the CNS is the blood brain barrier (BBB). A number of nanoparticulate formulations have been shown in earlier research to target receptors at the BBB and transport therapeutics into the CNS. However, no mechanism for CNS entrance and movement throughout the CNS parenchyma has been proposed yet. Here, the truncated mini low-density lipoprotein receptor-related protein 1 mLRP1_DIV* was presented as blood to brain transport carrier, exemplified by antibodies and immunoliposomes using a systematic approach to screen the receptor and its ligands' route across endothelial cells in vitro. Methods: The use of mLRP1_DIV* as liposomal carrier into the CNS was validated based on internalization and transport assays across an in vitro model of the BBB using hcMEC/D3 and bEnd.3 cells. Trafficking routes of mLRP1_DIV* and corresponding cargo across endothelial cells were analyzed using immunofluorescence. Modulation of γ-secretase activity by immunoliposomes loaded with the γ-secretase modulator BB25 was investigated in co-cultures of bEnd.3 mLRP1_DIV* cells and CHO cells overexpressing human amyloid precursor protein (APP) and presenilin 1 (PSEN1). Results: We showed that while expressed in vitro, mLRP1_DIV* transports both, antibodies and functionalized immunoliposomes from luminal to basolateral side across an in vitro model of the BBB, followed by their mLRP1_DIV* dependent release of the cargo. Importantly, functionalized liposomes loaded with the γ-secretase modulator BB25 were demonstrated to effectively reduce toxic Aß42 peptide levels after mLRP1_DIV* mediated transport across a co-cultured endothelial monolayer. Conclusion: Together, the data strongly suggest mLRP1_DIV* as a promising tool for drug delivery into the CNS, as it allows a straight transport of cargo from luminal to abluminal side across an endothelial monolayer and it's release into brain parenchyma in vitro, where it exhibits its intended therapeutic effect. [ABSTRACT FROM AUTHOR]

The blood–brain barrier (BBB) is essential for protection and plays a crucial role in chronic neurological disorders like small-vessel disease and Alzheimer's disease. Its complexity poses significant challenges for effective diagnostics and treatments, highlighting the need for novel animal models and comprehensive BBB dysfunction studies. This study investigates chronic BBB dysfunction induction using osmotic disruption via mannitol in healthy adult male Sprague Dawley rats over 12 weeks. Group 1 received 1 bolus/week (2.0 g/kg), Group 2 received 3 boluses/week (1.5 g/kg), and Group 3 received 3 boluses/week (2.5 g/kg). BBB dysfunction was assessed using gadolinium (Gd) infusion and MRI to evaluate location, severity, evolution, and persistence. MR spectroscopy (MRS) examined the brain metabolism changes due to intravenous mannitol, with T2-weighted MRI assessing brain lesions. Biomarkers of neuroinflammation were analyzed in the highest mannitol dose group. Our data show chronic BBB dysfunction primarily in the cortex, hippocampus, and striatum, but not in the corpus callosum of rats under periodic mannitol dosing in groups 1 and 2. MRS identified a distinctive metabolite signature, including changes in alanine, choline, and N-acetyl aspartate in the striatum of Group 1. No significant differences were found in the serum levels of all pro- and anti-inflammatory cytokines analyzed in the high-dose Group 3. This study underscores the feasibility and implications of using osmotic disruption to model chronic BBB dysfunction, offering insights for future neuroprotection and therapeutic strategies research. [ABSTRACT FROM AUTHOR]

Cerebral cavernous malformations (CCMs) are abnormal expansions of brain capillaries that increase the risk of hemorrhagic strokes, with CCM1 mutations responsible for about 50% of familial cases. The disorder can cause irreversible brain damage by compromising the blood–brain barrier (BBB), leading to fatal brain hemorrhages. Studies show that progesterone and its derivatives significantly impact BBB integrity. The three CCM proteins (CCM1, CCM2, and CCM3) form the CCM signaling complex (CSC), linking classic and non-classic progesterone signaling within the CmPn network, which is crucial for maintaining BBB integrity. This study aimed to explore the relationship between CCM1 and key pathways of the CmPn signaling network using three mouse embryonic fibroblast lines (MEFs) with distinct CCM1 expressions. Omics and systems biology analysis investigated CCM1-mediated signaling within the CmPn network. Our findings reveal that CCM1 is essential for regulating cellular processes within progesterone-mediated CmPn/CmP signaling, playing a crucial role in maintaining microvessel integrity. This regulation occurs partly through gene transcription control. The critical role of CCM1 in these processes suggests it could be a promising therapeutic target for CCMs. [ABSTRACT FROM AUTHOR]

IntroductionIschemic stroke is a devastating neurovascular condition that occurs when cerebral tissue fails to receive an adequate supply of oxygen. Despite being a leading cause of death and disability worldwide, therapeutic interventions are currently limited. Polyamidoamine (PAMAM) dendrimers are nanomolecules commonly used in biomedical applications due to their ability to encapsulate small-molecules and improve their pharmacokinetic properties. Curcumin is known to have anti-inflammatory and antioxidant effects yet suffers from poor solubility and bioavailability. The purpose of this study is to investigate the efficacy of curcumin encapsulated in PAMAM dendrimers as a potential therapeutic treatment for ischemic stroke by studying post-stroke lesion size, astrocyte reactivity, and functional recovery in a rat model of cerebral ischemia.MethodsForty-eight male and female Sprague-Dawley rats (280–380 g) underwent either a 90-min middle cerebral artery occlusion (MCAo) or sham surgery before receiving one of four treatments: (1) Hanks’ balanced salt solution (HBSS) control, (2) empty dendrimer control, (3) curcumin control, or (4) curcumin encapsulated in PAMAM dendrimer. Neurobehavioral outcomes were evaluated at 1-, 3-, 5-, and 7-day post-surgery, after which animals were euthanized on day 8 to assess infarct volume and GFAP immunoreactivity.ResultsAnimals that received formulations containing dendrimers (curcumin encapsulated in dendrimers or empty dendrimers) demonstrated significantly lower levels of GFAP immunoreactivity and improved functional recovery, including weight and neurobehavioral scores, compared to the formulations that did not contain dendrimers (curcumin and HBSS control). Additionally, the dendrimer-curcumin treatment group exhibited a significantly improved paw laterality index over the course of the study compared with the other three treatment groups.ConclusionAlthough the post-stroke administration of curcumin encapsulated in PAMAM dendrimers modulates the astrocytic response and promotes functional recovery following ischemic stroke in rats, its therapeutic benefits may be driven by PAMAM dendrimers as the empty dendrimer treatment group also showed significant improvements post-stroke. Further investigation regarding PAMAM dendrimers in treating neuroinflammatory conditions remains warranted.

Recent development of amyloid-β (Aβ)-targeted immunotherapies for Alzheimer’s disease (AD) have highlighted the need for accurate diagnostic methods. Antibody-based positron emission tomography (PET) ligands are well suited for this purpose as they can be directed toward the same target as the therapeutic antibody. Bispecific, brain-penetrating antibodies can achieve sufficient brain concentrations, but their slow blood clearance remains a challenge, since it prolongs the time required to achieve a target-specific PET signal. Here, two antibodies were designed based on the Aβ antibody bapineuzumab (Bapi) – one monospecific IgG (Bapi) and one bispecific antibody with an antigen binding fragment (Fab) of the transferrin receptor (TfR) antibody 8D3 fused to one of the heavy chains (Bapi-Fab8D3) for active, TfR-mediated transport into the brain. A variant of each antibody was designed to harbor a mutation to the neonatal Fc receptor (FcRn) binding domain, to increase clearance. Blood and brain pharmacokinetics of radiolabeled antibodies were studied in wildtype (WT) and AD mice (AppNL-G-F). The FcRn mutation substantially reduced blood half-life of both Bapi and Bapi-Fab8D3. Bapi-Fab8D3 showed high brain uptake and the brain-to-blood ratio of its FcRn mutated form was significantly higher in AppNL-G-F mice than in WT mice 12 h after injection and increased further up to 168 h. Ex vivo autoradiography showed specific antibody retention in areas with abundant Aβ pathology. Taken together, these results suggest that reducing FcRn binding of a full-sized bispecific antibody increases the systemic elimination and could thereby drastically reduce the time from injection to in vivo imaging.

Abstract Primary familial brain calcification (PFBC) is a genetic neurological disorder characterized by symmetric brain calcifications that manifest with variable neurological symptoms. This study aimed to explore the genetic basis of PFBC and elucidate the underlying pathophysiological mechanisms. Six patients from four pedigrees with brain calcification were enrolled. Whole-exome sequencing identified two novel homozygous variants, c.488G > T (p.W163L) and c.2135G > A (p.W712*), within the myogenesis regulating glycosidase (MYORG) gene. Cerebellar ataxia (n = 5) and pyramidal signs (n = 4) were predominant symptoms, with significant clinical heterogeneity noted even within the same family. An autopsy of one patient revealed extensive brainstem calcifications, sparing the cerebral cortex, and marked by calcifications predominantly in capillaries and arterioles. The pathological study suggested morphological alterations characterized by shortened foot processes within astrocytes in regions with pronounced calcification and decreased immunoreactivity of AQP4. The morphology of astrocytes in regions without calcification remains preserved. Neuronal loss and gliosis were observed in the basal ganglia, thalamus, brainstem, cerebellum, and dentate nucleus. Notably, olivary hypertrophy, a previously undescribed feature in MYORG-PFBC, was discovered. Neuroimaging showed reduced blood flow in the cerebellum, highlighting the extent of cerebellar involvement. Among perivascular cells constituting the blood-brain barrier (BBB) and neurovascular unit, MYORG is most highly expressed in astrocytes. Astrocytes are integral components of the BBB, and their dysfunction can precipitate BBB disruption, potentially leading to brain calcification and subsequent neuronal loss. This study presents two novel homozygous variants in the MYORG gene and highlights the pivotal role of astrocytes in the development of brain calcifications, providing insights into the pathophysiological mechanisms underlying PFBC associated with MYORG variants.

Primary familial brain calcification (PFBC) is a genetic neurological disorder characterized by symmetric brain calcifications that manifest with variable neurological symptoms. This study aimed to explore the genetic basis of PFBC and elucidate the underlying pathophysiological mechanisms. Six patients from four pedigrees with brain calcification were enrolled. Whole-exome sequencing identified two novel homozygous variants, c.488G > T (p.W163L) and c.2135G > A (p.W712*), within the myogenesis regulating glycosidase (MYORG) gene. Cerebellar ataxia (n = 5) and pyramidal signs (n = 4) were predominant symptoms, with significant clinical heterogeneity noted even within the same family. An autopsy of one patient revealed extensive brainstem calcifications, sparing the cerebral cortex, and marked by calcifications predominantly in capillaries and arterioles. The pathological study suggested morphological alterations characterized by shortened foot processes within astrocytes in regions with pronounced calcification and decreased immunoreactivity of AQP4. The morphology of astrocytes in regions without calcification remains preserved. Neuronal loss and gliosis were observed in the basal ganglia, thalamus, brainstem, cerebellum, and dentate nucleus. Notably, olivary hypertrophy, a previously undescribed feature in MYORG-PFBC, was discovered. Neuroimaging showed reduced blood flow in the cerebellum, highlighting the extent of cerebellar involvement. Among perivascular cells constituting the blood-brain barrier (BBB) and neurovascular unit, MYORG is most highly expressed in astrocytes. Astrocytes are integral components of the BBB, and their dysfunction can precipitate BBB disruption, potentially leading to brain calcification and subsequent neuronal loss. This study presents two novel homozygous variants in the MYORG gene and highlights the pivotal role of astrocytes in the development of brain calcifications, providing insights into the pathophysiological mechanisms underlying PFBC associated with MYORG variants. [ABSTRACT FROM AUTHOR]

The maturation of brain microvascular endothelial cells leads to the formation of a tightly sealed monolayer, known as the blood-brain barrier (BBB). The BBB damage is associated with the pathogenesis of age-related neurodegenerative diseases including vascular cognitive impairment and Alzheimer's disease. Growing knowledge in the field of epigenetics can enhance the understanding of molecular profile of the BBB and has great potential for the development of novel therapeutic strategies or targets to repair a disrupted BBB. Histone deacetylases (HDACs) inhibitors are epigenetic regulators that can induce acetylation of histones and induce open chromatin conformation, promoting gene expression by enhancing the binding of DNA with transcription factors. We investigated how HDAC inhibition influences the barrier integrity using immortalized human endothelial cells (HCMEC/D3) and the human induced pluripotent stem cell (iPSC)-derived brain vascular endothelial cells. The endothelial cells were treated with or without a novel compound named W2A-16. W2A-16 not only activates Wnt/ß-catenin signaling but also functions as a class I HDAC inhibitor. We demonstrated that the administration with W2A-16 sustained barrier properties of the monolayer of endothelial cells, as evidenced by increased trans-endothelial electrical resistance (TEER). The BBB-related genes and protein expression were also increased compared with non-treated controls. Analysis of transcript profiles through RNA-sequencing in hCMEC/D3 cells indicated that W2A-16 potentially enhances BBB integrity by influencing genes associated with the regulation of the extracellular microenvironment. These findings collectively propose that the HDAC inhibition by W2A-16 plays a facilitating role in the formation of the BBB. Pharmacological approaches to inhibit HDAC may be a potential therapeutic strategy to boost and/or restore BBB integrity. [ABSTRACT FROM AUTHOR]

Cerebral small vessel diseases (CSVD) are neurological disorders associated with microvessels, manifested pathologically as white matter (WM) changes and cortical microbleeds, with hypertension as a risk factor. Additionally, a high-fat diet (HFD) can affect peripheral vessel health. Our study explored how HFD affects cerebral small vessels in normotensive WKY, hypertensive SHR, and SHR/SP rats. The MRI results revealed that HFD specifically increased WM hyperintensity in SHR/SP rats. Pathologically, it increased WM pallor and vacuolation in SHR and SHR/SP rats. Levels of blood–brain barrier (BBB) protein claudin 5 were decreased in SHR and SHR/SP compared to WKY, with HFD having minimal impact on these levels. Conversely, collagen IV levels remained consistent among the rat strains, which were increased by HFD. Consequently, HFD caused vessel leakage in all rat strains, particularly within the corpus callosum of SHR/SP rats. To understand the underlying mechanisms, we assessed the levels of hypoxia-inducible factor-1α (HIF-1α), Gp91-phox, and neuroinflammatory markers astrocytes, and microglia were increased in SHR and SHR/SP compared to WKY and were further elevated by HFD in all rat strains. Gp91-phox was also increased in SHR and SHR/SP compared to WKY, with HFD causing an increase in WKY but little effect in SHR and SHR/SP. In conclusion, our study demonstrates that HFD, in combined with hypertension, intensifies cerebral pathological alterations in CSVD rats. This exacerbation involves increased oxidative stress and HIF-1α in cerebral vessels, triggering neuroinflammation, vascular basement membrane remodeling, IgG leakage, and ultimately WM damage. [ABSTRACT FROM AUTHOR]

The mechanisms underlying pathological changes in the central nervous system (CNS) following Coxsackievirus A16 (CV-A16) infection have not yet been elucidated. IFN-γ-inducible protein-10 (IP-10) is often used as a predictive factor to monitor early virus infection. It has also been reported that IP-10 plays a pivotal role in neuroinflammation. In this study, we aimed to explore the role of IP-10 in the neuropathogenesis of CV-A16 infection. We observed that the level of IP-10, as well as the TLR3-TRIF-TRAF3-TBK1-NF-κB and RIG-I/MDA5-MAVS-TRAFS-TBK1-NF-κB pathways, which are the upstream of IP-10, were significantly elevated during the course of CV-A16 infection. This increase was accompanied by an increase in a series of inflammatory cytokines at different time-points during CV-A16 infection. To determine whether IP-10 influences BBB integrity, we examined junctional complexes. Our results revealed that the expression levels of Claudin5, Occludin, ZO-1 and VE-Cadherin were notably decreased in CV-A16-infected HUVECs, but these indicators were restored in CV-A16-infected HUVECs with Eldelumab treatment. Nevertheless, IP-10 is only a chemokine that primarily traffics CXCR3-positive immune cells to inflammatory sites or promotes the production of inflammatory cytokines. Therefore, the interactions between IP-10 and inflammatory cytokines were evaluated. Our data revealed that IP-10 mediated the production of TNF-α, which was also observed to change the junctional complexes. Moreover, in a suckling mouse model, IP-10 and TNF-α treatments exacerbated clinical symptoms, mortality and pathological changes in the brain of CV-A16-infected mice, but Anti-IP-10 and Anti-TNF-α treatments alleviated these changes. Our data also revealed that IP-10 may be detected early in CV-A16 infection, whereas TNF-α was detected late in CV-A16 infection, and the production of TNF-α was also found to be positively correlated with IP-10. In addition, IP-10 and TNF-α were observed to reduce junctional complexes and enhance virus entry into the CNS. Taken together, this study provides the first evidence that CV-A16 activates the IP-10/TNF-α regulatory axis to cause BBB damage and accelerate the formation of neuroinflammation in infected hosts, which not only provides a new understanding of the neuropathogenesis caused by CV-A16, but also offers a promising target for the development of CV-A16 antiviral drugs.

BACKGROUND Recent advancements in animal studies have demonstrated the potential of normobaric hyperoxia (NBO) as a promising intervention for preserving the integrity of the blood–brain barrier (BBB). However, there is still limited understanding of the effects of NBO on BBB function in patients with clinical stroke. Therefore, the objective of this study was to investigate the efficacy of NBO therapy in attenuating BBB damage and reducing brain injury in individuals undergoing endovascular treatment (EVT) for acute stroke. METHODS AND RESULTS This study enrolled patients from the OPENS‐1 (Normobaric Hyperoxia Combined With Reperfusion for Acute Ischemic Stroke) study, with 43 patients receiving NBO combined with EVT and 43 patients receiving EVT alone. The main outcome measures included serum levels of occludin, MMP‐9 (matrix metalloproteinase‐9), NSE (neuron‐specific enolase), and S100b at 24 hours and 7 days, as well as the intracranial extravasation rate at 24 hours. Serum markers were assessed using ELISA, and intracranial contrast extravasation was visualized using dual‐energy computed tomography scan. We analyzed a total of 86 patients and found that the 24‐hour serum markers levels of BBB damage and brain injury were significantly lower in the group receiving NBO therapy combined with EVT compared with the group receiving EVT alone. Similarly, at 7 days, the levels of occludin, MMP‐9, and NSE were lower in the NBO+EVT group. We also found that the 24‐hour serum levels of occludin and MMP‐9 were correlated with intracranial contrast extravasation. Additionally, the incidence of intracranial contrast extravasation was lower in the NBO+EVT group compared with the EVT group (35.9% versus 60.5%, P=0.031). CONCLUSIONS This study offers valuable insights into the positive impact of NBO on maintaining BBB integrity and reducing brain injury in patients with acute stroke undergoing EVT.

Human immunodeficiency virus (HIV-1) remains a persistent global health crisis. Even while successfully virologically suppressed, people with HIV (PWH) experience a higher risk for inflammatory disorders such as HIV-associated neurocognitive disorder (HAND). Tobacco use puts PWH at higher risk for neurocognitive symptoms resulting from HIV-associated neuroinflammation. The NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome has been implicated as a driver of HIV-associated inflammation, including HAND. Nicotine, the psychoactive component of tobacco smoke, has also been shown to signal through the NLRP3 inflammasome and modulate inflammatory signaling in the CNS. Here, we explore the impacts of nicotine and tobacco on the complex neurobiology of HAND, including effects on cognition, inflammation, viral latency, and blood-brain barrier integrity. We outline nicotine’s role in the establishment of active and latent infection in the brain and posit the NLRP3 inflammasome as a common pathway by which HIV-1 and nicotine promote neuroinflammation in PWH.

Abstract Blood–brain barrier (BBB) peptide-shuttles (BBBpS) are able to translocate the BBB and reach the brain. Despite the importance of brain targeting in pharmacology, BBBpS are poorly characterized. Currently, their development relies on the empiric assumption that cell-penetrating peptides (CPPs), with proven ability to traverse lipid membranes, will likewise behave as a BBBpS. The relationship between CPPs/BBBpS remains elusive and, to the best of our knowledge, has not hitherto been subject to thorough experimental scrutiny. In this work, we have identified/quantified the main physicochemical properties of BBBpS and then searched for CPPs with these properties, hence potential BBBpS. The specific features found for BBBpS are: (i) small size, (ii) none or few aromatic residues, (iii) hydrophobic, and (iv) slight cationic nature. Then, we selected the 10 scoring best in an ordinary least squares analysis, and tested them in vitro and in vivo. Overall, we identified the molecular determinants for brain targeting by peptides, devised a methodology that can be used to assist in the design of peptides with potential brain penetration from amino acid residue sequences, and found four new BBBpS within the CPP library. Graphical Abstract

Abstract Background Brain metastasis (BM) is common among cases of advanced non-small cell lung cancer (NSCLC) and is the leading cause of death for these patients. Mesothelin (MSLN), a tumor-associated antigen expressed in many solid tumors, has been reported to be involved in the progression of multiple tumors. However, its potential involvement in BM of NSCLC and the underlying mechanism remain unknown. Methods The expression of MSLN was validated in clinical tissue and serum samples using immunohistochemistry and enzyme-linked immunosorbent assay. The ability of NSCLC cells to penetrate the blood-brain barrier (BBB) was examined using an in vitro Transwell model and an ex vivo multi-organ microfluidic bionic chip. Immunofluorescence staining and western blotting were used to detect the disruption of tight junctions. In vivo BBB leakiness assay was performed to assess the barrier integrity. MET expression and activation was detected by western blotting. The therapeutic efficacy of drugs targeting MSLN (anetumab) and MET (crizotinib/capmatinib) on BM was evaluated in animal studies. Results MSLN expression was significantly elevated in both serum and tumor tissue samples from NSCLC patients with BM and correlated with a poor clinical prognosis. MSLN significantly enhanced the brain metastatic abilities of NSCLC cells, especially BBB extravasation. Mechanistically, MSLN facilitated the expression and activation of MET through the c-Jun N-terminal kinase (JNK) signaling pathway, which allowed tumor cells to disrupt tight junctions and the integrity of the BBB and thereby penetrate the barrier. Drugs targeting MSLN (anetumab) and MET (crizotinib/capmatinib) effectively blocked the development of BM and prolonged the survival of mice. Conclusions Our results demonstrate that MSLN plays a critical role in BM of NSCLC by modulating the JNK/MET signaling network and thus, provides a potential novel therapeutic target for preventing BM in NSCLC patients.

Abstract Background Although abnormal accumulation of amyloid beta (Aβ) protein is thought to be the main cause of Alzheimer’s disease (AD), emerging evidence suggests a pivotal vascular contribution to AD. Aberrant amyloid β induces neurovascular dysfunction, leading to changes in the morphology and function of the microvasculature. However, little is known about the underlying mechanisms between Aβ deposition and vascular injuries. Recent studies have revealed that pericytes play a substantial role in the vasculopathy of AD. Additional research is imperative to attain a more comprehensive understanding. Methods Two-photon microscopy and laser speckle imaging were used to examine cerebrovascular dysfunction. Aβ oligomer stereotactic injection model was established to explain the relationship between Aβ and vasculopathy. Immunofluorescence staining, western blot, and real-time PCR were applied to detect the morphological and molecular alternations of pericytes. Primary cultured pericytes and bEnd.3 cells were employed to explore the underlying mechanisms. Results Vasculopathy including BBB damage, hypoperfusion, and low vessel density were found in the cortex of 8 to 10-month-old 5xFAD mice. A similar phenomenon accompanied by pericyte degeneration appeared in an Aβ-injected model, suggesting a direct relationship between Aβ and vascular dysfunction. Pericytes showed impaired features including low PDGFRβ expression and increased pro-inflammatory chemokines secretion under the administration of Aβ in vitro, of which supernatant cultured with bEND.3 cells led to significant endothelial dysfunction characterized by TJ protein deficiency. Conclusions Our results provide new insights into the pathogenic mechanism underlying Aβ-induced vasculopathy. Targeting pericyte therapies are promising to ameliorate vascular dysfunction in AD.

Blood–brain barrier (BBB) peptide-shuttles (BBBpS) are able to translocate the BBB and reach the brain. Despite the importance of brain targeting in pharmacology, BBBpS are poorly characterized. Currently, their development relies on the empiric assumption that cell-penetrating peptides (CPPs), with proven ability to traverse lipid membranes, will likewise behave as a BBBpS. The relationship between CPPs/BBBpS remains elusive and, to the best of our knowledge, has not hitherto been subject to thorough experimental scrutiny. In this work, we have identified/quantified the main physicochemical properties of BBBpS and then searched for CPPs with these properties, hence potential BBBpS. The specific features found for BBBpS are: (i) small size, (ii) none or few aromatic residues, (iii) hydrophobic, and (iv) slight cationic nature. Then, we selected the 10 scoring best in an ordinary least squares analysis, and tested them in vitro and in vivo. Overall, we identified the molecular determinants for brain targeting by peptides, devised a methodology that can be used to assist in the design of peptides with potential brain penetration from amino acid residue sequences, and found four new BBBpS within the CPP library. [ABSTRACT FROM AUTHOR]

Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumour that occurs in the pons of the brainstem and accounts for over 80% of all brainstem gliomas. The median age at diagnosis is 6--7 years old, with less than 10% overall survival 2 years after diagnosis and less than 1% after 5 years. DIPGs are surgically inaccessible, and radiation therapy provides only transient benefit, with death ensuing from relentless local tumour infiltration. DIPGs are now the leading cause of brain tumour deaths in children, with a societal cancer burden in years of life lost (YLL) of more than 67 per individual, versus approximately 14 and 16 YLL for lung and breast cancer respectively. More than 95 clinical drug trials have been conducted on children with DIPGs, and all have failed to improve survival. No single or combination chemotherapeutic strategy has been successful to date because of our inability to identify targeted drugs for this disease and to deliver these drugs across an intact blood-brain barrier (BBB). Accordingly, there has been an increased focus on immunotherapy research in DIPG, with explorations into treatments such as chimeric antigen receptor T (CAR-T) cells, immune checkpoint blockades, cancer vaccines, and autologous cell transfer therapy. Here, we review the most recent advances in identifying genetic factors influencing the development of immunotherapy for DIPG. Additionally, we explore emerging technologies such as Magnetic Resonance-guided Focused Ultrasound (MRgFUS) in potential combinatorial approaches to treat DIPG. [ABSTRACT FROM AUTHOR]

This article discusses the challenges and potential strategies for treating glioblastoma (GBM), an aggressive type of brain tumor. It explores the immunosuppressive tumor microenvironment and the blood-brain barrier as barriers to effective treatment. The article discusses various immunotherapy strategies and other approaches for preclinical studies. It also highlights the role of neutrophils and macrophages in promoting tumor growth. The article emphasizes the complexity of GBM and the need for a multidisciplinary approach to improve patient outcomes. The document provides a list of references that offer a comprehensive overview of current research on GBM treatment and the need for further investigation into novel therapeutic approaches. [Extracted from the article]

Overcoming the blood–brain barrier (BBB) remains a significant hurdle in effective drug delivery to the brain. While the BBB serves as a crucial protective barrier, it poses challenges in delivering therapeutic agents to their intended targets within the brain parenchyma. To enhance drug delivery for the treatment of neurological diseases, several delivery technologies to circumvent the BBB have been developed in the last few years. Among them, nanoparticles (NPs) are one of the most versatile and promising tools. Here, we summarize the characteristics of NPs that facilitate BBB penetration, including their size, shape, chemical composition, surface charge, and importantly, their conjugation with various biological or synthetic molecules such as glucose, transferrin, insulin, polyethylene glycol, peptides, and aptamers. Additionally, we discuss the coating of NPs with surfactants. A comprehensive overview of the common in vitro and in vivo models of the BBB for NP penetration studies is also provided. The discussion extends to discussing BBB impairment under pathological conditions and leveraging BBB alterations under pathological conditions to enhance drug delivery. Emphasizing the need for future studies to uncover the inherent therapeutic properties of NPs, the review advocates for their role beyond delivery systems and calls for efforts translating NPs to the clinic as therapeutics. Overall, NPs stand out as a highly promising therapeutic strategy for precise BBB targeting and drug delivery in neurological disorders. [ABSTRACT FROM AUTHOR]

Background: Brain metastasis (BM) is common among cases of advanced non-small cell lung cancer (NSCLC) and is the leading cause of death for these patients. Mesothelin (MSLN), a tumor-associated antigen expressed in many solid tumors, has been reported to be involved in the progression of multiple tumors. However, its potential involvement in BM of NSCLC and the underlying mechanism remain unknown. Methods: The expression of MSLN was validated in clinical tissue and serum samples using immunohistochemistry and enzyme-linked immunosorbent assay. The ability of NSCLC cells to penetrate the blood-brain barrier (BBB) was examined using an in vitro Transwell model and an ex vivo multi-organ microfluidic bionic chip. Immunofluorescence staining and western blotting were used to detect the disruption of tight junctions. In vivo BBB leakiness assay was performed to assess the barrier integrity. MET expression and activation was detected by western blotting. The therapeutic efficacy of drugs targeting MSLN (anetumab) and MET (crizotinib/capmatinib) on BM was evaluated in animal studies. Results: MSLN expression was significantly elevated in both serum and tumor tissue samples from NSCLC patients with BM and correlated with a poor clinical prognosis. MSLN significantly enhanced the brain metastatic abilities of NSCLC cells, especially BBB extravasation. Mechanistically, MSLN facilitated the expression and activation of MET through the c-Jun N-terminal kinase (JNK) signaling pathway, which allowed tumor cells to disrupt tight junctions and the integrity of the BBB and thereby penetrate the barrier. Drugs targeting MSLN (anetumab) and MET (crizotinib/capmatinib) effectively blocked the development of BM and prolonged the survival of mice. Conclusions: Our results demonstrate that MSLN plays a critical role in BM of NSCLC by modulating the JNK/MET signaling network and thus, provides a potential novel therapeutic target for preventing BM in NSCLC patients. [ABSTRACT FROM AUTHOR]

Treating brain disease is challenging, and the Zika virus (ZIKV) presents a unique obstacle due to its neuroinvasive nature. In this review, we discuss the immunopathogenesis of ZIKV and explore how the virus interacts with the body's immune responses and the role of the protein Mfsd2a in maintaining the integrity of the blood–brain barrier (BBB) during ZIKV neuroinvasion. ZIKV has emerged as a significant public health concern due to its association with severe neurological problems, including microcephaly and Gillain–Barré Syndrome (GBS). Understanding its journey through the brain—particularly its interaction with the placenta and BBB—is crucial. The placenta, which is designed to protect the fetus, becomes a pathway for ZIKV when infected. The BBB is composed of brain endothelial cells, acts as a second barrier, and protects the fetal brain. However, ZIKV finds ways to disrupt these barriers, leading to potential damage. This study explores the mechanisms by which ZIKV enters the CNS and highlights the role of transcytosis, which allows the virus to move through the cells without significantly disrupting the BBB. Although the exact mechanisms of transcytosis are unclear, research suggests that ZIKV may utilize this pathway. [ABSTRACT FROM AUTHOR]

In CNS drug discovery, the estimation of brain exposure to lead compounds is critical for their optimization. Compounds need to cross the blood–brain barrier (BBB) to reach the pharmacological targets in the CNS. The BBB is a complex system involving passive and active mechanisms of transport and efflux transporters such as P-glycoproteins (P-gp) and breast cancer resistance protein (BCRP), which play an essential role in CNS penetration of small molecules. Several in vivo, in vitro, and in silico methods are available to estimate human brain penetration. Preclinical species are used as in vivo models to understand unbound brain exposure by deriving the Kp,uu parameter and the brain/plasma ratio of exposure corrected with the plasma and brain free fraction. The MDCK-mdr1 (Madin Darby canine kidney cells transfected with the MDR1 gene encoding for the human P-gp) assay is the commonly used in vitro assay to estimate compound permeability and human efflux. The in silico methods to predict brain exposure, such as CNS MPO, CNS BBB scores, and various machine learning models, help save costs and speed up compound discovery and optimization at all stages. These methods enable the screening of virtual compounds, building of a CNS penetrable compounds library, and optimization of lead molecules for CNS penetration. Therefore, it is crucial to understand the reliability and ability of these methods to predict CNS penetration. We review the in silico, in vitro, and in vivo data and their correlation with each other, as well as assess published experimental and computational approaches to predict the BBB penetrability of compounds. [ABSTRACT FROM AUTHOR]

Background: Although abnormal accumulation of amyloid beta (Aβ) protein is thought to be the main cause of Alzheimer's disease (AD), emerging evidence suggests a pivotal vascular contribution to AD. Aberrant amyloid β induces neurovascular dysfunction, leading to changes in the morphology and function of the microvasculature. However, little is known about the underlying mechanisms between Aβ deposition and vascular injuries. Recent studies have revealed that pericytes play a substantial role in the vasculopathy of AD. Additional research is imperative to attain a more comprehensive understanding. Methods: Two-photon microscopy and laser speckle imaging were used to examine cerebrovascular dysfunction. Aβ oligomer stereotactic injection model was established to explain the relationship between Aβ and vasculopathy. Immunofluorescence staining, western blot, and real-time PCR were applied to detect the morphological and molecular alternations of pericytes. Primary cultured pericytes and bEnd.3 cells were employed to explore the underlying mechanisms. Results: Vasculopathy including BBB damage, hypoperfusion, and low vessel density were found in the cortex of 8 to 10-month-old 5xFAD mice. A similar phenomenon accompanied by pericyte degeneration appeared in an Aβ-injected model, suggesting a direct relationship between Aβ and vascular dysfunction. Pericytes showed impaired features including low PDGFRβ expression and increased pro-inflammatory chemokines secretion under the administration of Aβ in vitro, of which supernatant cultured with bEND.3 cells led to significant endothelial dysfunction characterized by TJ protein deficiency. Conclusions: Our results provide new insights into the pathogenic mechanism underlying Aβ-induced vasculopathy. Targeting pericyte therapies are promising to ameliorate vascular dysfunction in AD. [ABSTRACT FROM AUTHOR]

Glioblastoma multiform (GBM), the most occurring brain tumor comprises radiation therapy, chemotherapy, and surgery as its treatment modalities. A significant hurdle is the insufficient or impeded transport of drugs to the central nervous system (CNS), linked to the protective influence of the blood-brain barrier (BBB). Nanotechnology can help to deliver therapeutic drugs into the central nervous system (CNS) by crossing the BBB. Paclitaxel (PTX) is a broad-spectrum anticancer compound that possesses scientifically proven anticancer activity. Despite having limited applications due to partial solubility and toxicity due to cosolvent preparation, it has shown encouraging outcomes in the treatment of GBM. In these cases, nanotechnology and nanoparticles added certain advantages such as increasing drug half-life, lowering toxicity, and enhancing the permeability and retention across BBB in tumor targeting. This review article is aimed at summarizing the current state of research works on nanotechnology and nanoparticles (NPs) containing PTX in the treatment of Glioblastoma.

The functional and structural integrity of the blood–brain barrier is crucial in maintaining homeostasis in the brain microenvironment; however, the molecular mechanisms underlying the formation and function of the blood–brain barrier remain poorly understood. The major facilitator superfamily domain containing 2A has been identified as a key regulator of blood–brain barrier function. It plays a critical role in promoting and maintaining the formation and functional stability of the blood–brain barrier, in addition to the transport of lipids, such as docosahexaenoic acid, across the blood–brain barrier. Furthermore, an increasing number of studies have suggested that major facilitator superfamily domain containing 2A is involved in the molecular mechanisms of blood–brain barrier dysfunction in a variety of neurological diseases; however, little is known regarding the mechanisms by which major facilitator superfamily domain containing 2A affects the blood–brain barrier. This paper provides a comprehensive and systematic review of the close relationship between major facilitator superfamily domain containing 2A proteins and the blood–brain barrier, including their basic structures and functions, cross-linking between major facilitator superfamily domain containing 2A and the blood–brain barrier, and the in-depth studies on lipid transport and the regulation of blood–brain barrier permeability. This comprehensive systematic review contributes to an in-depth understanding of the important role of major facilitator superfamily domain containing 2A proteins in maintaining the structure and function of the blood–brain barrier and the research progress to date. This will not only help to elucidate the pathogenesis of neurological diseases, improve the accuracy of laboratory diagnosis, and optimize clinical treatment strategies, but it may also play an important role in prognostic monitoring. In addition, the effects of major facilitator superfamily domain containing 2A on blood–brain barrier leakage in various diseases and the research progress on cross-blood–brain barrier drug delivery are summarized. This review may contribute to the development of new approaches for the treatment of neurological diseases.

AbstractThe blood-brain barrier (BBB) is a multicellular neurovascular unit that serves as a highly impermeable cellular barrier to regulate brain homeostasis, protect the central nervous system, and respond to different physiological and pathological states. Recently, new drugs have been discovered to treat neuropathology. However, because BBB blocks the delivery of drugs to the central nervous system (CNS), it is still difficult to translate the treatment of CNS diseases into clinical results. Therefore, overcoming the BBB and realizing efficient delivery of therapeutic drugs is of great significance for the diagnosis and treatment of various neurological diseases such as Alzheimer’s disease, Parkinson’s disease and glioblastoma. Nano drug delivery system (NDDS) has the characteristics of high biocompatibility, high drug load, improving pharmacokinetic behavior of drugs in vivo, achieving targeted drug delivery, controlled drug release, etc. Therefore, in the field of trans-BBB drug delivery, It has broad application prospect for the diagnosis and treatment of various neurological diseases. This paper reviews the latest research on NDDS crossing BBB at home and abroad, providing new ideas for the diagnosis and treatment of CNS diseases.

Abstract Background Blood-brain barrier (BBB) models based on primary murine, bovine, and porcine brain capillary endothelial cell cultures have long been regarded as robust models with appropriate properties to examine the functional transport of small molecules. However, species differences sometimes complicate translating results from these models to human settings. During the last decade, brain capillary endothelial-like cells (BCECs) have been generated from stem cell sources to model the human BBB in vitro. The aim of the present study was to establish and characterize a human BBB model using human induced pluripotent stem cell (hiPSC)-derived BCECs from the hIPSC line SBAD0201. Methods The model was evaluated using transcriptomics, proteomics, immunocytochemistry, transendothelial electrical resistance (TEER) measurements, and, finally, transport assays to assess the functionality of selected transporters and receptor (GLUT-1, LAT-1, P-gp and LRP-1). Results The resulting BBB model displayed an average TEER of 5474 ± 167 Ω·cm2 and cell monolayer formation with claudin-5, ZO-1, and occludin expression in the tight junction zones. The cell monolayers expressed the typical BBB markers VE-cadherin, VWF, and PECAM-1. Transcriptomics and quantitative targeted absolute proteomics analyses revealed that solute carrier (SLC) transporters were found in high abundance, while the expression of efflux transporters was relatively low. Transport assays using GLUT-1, LAT-1, and LRP-1 substrates and inhibitors confirmed the functional activities of these transporters and receptors in the model. A transport assay suggested that P-gp was not functionally expressed in the model, albeit antibody staining revealed that P-gp was localized at the luminal membrane. Conclusions In conclusion, the novel SBAD0201-derived BBB model formed tight monolayers and was proven useful for studies investigating GLUT-1, LAT-1, and LRP-1 mediated transport across the BBB. However, the model did not express functional P-gp and thus is not suitable for the performance of drug efflux P-gp reletated studies.

Background: The blood–brain barrier (BBB) strictly regulates the penetration of substances into the brain, which, although important for maintaining brain homeostasis, may delay drug development because of the difficulties in predicting pharmacokinetics/pharmacodynamics (PKPD), toxicokinetics/toxicodynamics (TKTD), toxicity, safety, and efficacy in the central nervous system (CNS). Moreover, BBB functional proteins show species differences; therefore, humanized in vitro BBB models are urgently needed to improve the predictability of preclinical studies. Recently, international trends in the 3Rs in animal experiments and the approval of the FDA Modernization Act 2.0 have accelerated the application of microphysiological systems (MPSs) in preclinical studies, and in vitro BBB models have become synonymous with BBB–MPSs. Recently, we developed an industrialized humanized BBB–MPS, BBB–NET. In our previous report, we reproduced transferrin receptor (TfR)–mediated transcytosis with high efficiency and robustness, using hydrogels including fibrin and collagen I microfibers (CMFs). Methods: We investigated how adding CMFs to the fibrin gel benefits BBB-NETs. Results: We showed that CMFs accelerate capillary network formation and maturation by promoting astrocyte (AC) survival, and clarified that integrin β1 is involved in the mechanism of CMFs. Conclusions: Our data suggest that the quality control (QC) of CMFs is important for ensuring the stable production of BBB–NETs.

Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumour that occurs in the pons of the brainstem and accounts for over 80% of all brainstem gliomas. The median age at diagnosis is 6–7 years old, with less than 10% overall survival 2 years after diagnosis and less than 1% after 5 years. DIPGs are surgically inaccessible, and radiation therapy provides only transient benefit, with death ensuing from relentless local tumour infiltration. DIPGs are now the leading cause of brain tumour deaths in children, with a societal cancer burden in years of life lost (YLL) of more than 67 per individual, versus approximately 14 and 16 YLL for lung and breast cancer respectively. More than 95 clinical drug trials have been conducted on children with DIPGs, and all have failed to improve survival. No single or combination chemotherapeutic strategy has been successful to date because of our inability to identify targeted drugs for this disease and to deliver these drugs across an intact blood-brain barrier (BBB). Accordingly, there has been an increased focus on immunotherapy research in DIPG, with explorations into treatments such as chimeric antigen receptor T (CAR-T) cells, immune checkpoint blockades, cancer vaccines, and autologous cell transfer therapy. Here, we review the most recent advances in identifying genetic factors influencing the development of immunotherapy for DIPG. Additionally, we explore emerging technologies such as Magnetic Resonance-guided Focused Ultrasound (MRgFUS) in potential combinatorial approaches to treat DIPG.

Hemorrhagic transformation (HT) and restrictive therapeutic time window are significant limitations of delayed t-PA (tissue-type plasminogen activator) thrombolytic therapy in ischemic stroke patients. Plant Momordica charantia-derived exosome-like nanovesicles (MC-ELNs) can protect the blood–brain barrier (BBB) and inhibit neuronal apoptosis in stroke rats by inhibiting matrix metalloproteinase 9(MMP-9) expression. This study explored the therapeutic function and underlying mechanisms of MC-ELNs in treating HT. In delayed t-PA-treated ischemia-reperfusion rats, MC-ELNs significantly reduced mortality, HT, and cell apoptosis; MC-ELNs improved neurological function and BBB's integrity. MC-ELNs reduced ONOO− and MMP-9 expression and inhibited the release of HMGB1 from intracellular to extracellular in vivo and in vitro. ONOO− donor SIN-1 directly induced extracellular secretion of HMGB1, MC-ELNs and FeTmPyP (ONOO− decomposition catalyst, PDC) significantly reduced the expression of HMGB1 and inhibited MMP-9 activation in vitro. These findings indicate that MC-ELNs could protect BBB integrity and improve t-PA-induced HT by inhibiting the ONOO−/HMGB1/MMP-9 pathway.

Traumatic brain injury (TBI) leads to brain damage, comprising both immediate primary damage and a subsequent cascade of secondary injury mechanisms. The primary injury results in localized brain damage, while the secondary damage initiates inflammatory responses, followed by the disruption of the blood-brain barrier, infiltration of peripheral blood cells, brain edema, and the release of various immune mediators, including chemotactic factors and interleukins. TBI disrupts molecular signaling, cell structures, and functions. In addition to physical tissue damage, such as axonal injuries, contusions, and haemorrhages, TBI interferes with brain functioning, impacting cognition, decision-making, memory, attention, and speech capabilities. Despite a deep understanding of the pathophysiology of TBI, an intensive effort to evaluate the underlying mechanisms with effective therapeutic interventions is imperative to manage the repercussions of TBI. Studies have commenced to explore the potential of employing natural compounds as therapeutic interventions for TBI. These compounds are characterized by their low toxicity and limited interactions with conventional drugs. Moreover, many natural compounds demonstrate the capacity to target various aspects of the secondary injury process. While our understanding of the pathophysiology of TBI, there is an urgent need for effective therapeutic interventions to mitigate its consequences. Here, we aimed to summarize the mechanism of action and the role of phytochemicals against TBI progression. This review discusses the therapeutic implications of various phytonutrients and addresses primary and secondary consequences of TBI. In addition, we highlighted the roles of emerging phytochemicals as promising candidates for therapeutic intervention of TBI. The review highlights the neuroprotective roles of phytochemicals against TBI and the mechanistic approach. Furthermore, our efforts focused on the underlying mechanisms, providing a better understanding of the therapeutic potential of phytochemicals in TBI therapeutics. [ABSTRACT FROM AUTHOR]