Blood-Brain Barrier Overview: Structural and Functional Correlation

The pivotal role of microglia in injury and the prognosis of subarachnoid hemorrhage

Subarachnoid hemorrhage leads to a series of pathological changes, including vascular spasm, cellular apoptosis, blood-brain barrier damage, cerebral edema, and white matter injury. Microglia, which are the key immune cells in the central nervous system, maintain homeostasis in the neural environment, support neurons, mediate apoptosis, participate in immune regulation, and have neuroprotective effects. Increasing evidence has shown that microglia play a pivotal role in the pathogenesis of subarachnoid hemorrhage and affect the process of injury and the prognosis of subarachnoid hemorrhage. Moreover, microglia play certain neuroprotective roles in the recovery phase of subarachnoid hemorrhage. Several approaches aimed at modulating microglia function are believed to attenuate subarachnoid hemorrhage injury. This provides new targets and ideas for the treatment of subarachnoid hemorrhage. However, an in-depth and comprehensive summary of the role of microglia after subarachnoid hemorrhage is still lacking. This review describes the activation of microglia after subarachnoid hemorrhage and their roles in the pathological processes of vasospasm, neuroinflammation, neuronal apoptosis, blood-brain barrier disruption, cerebral edema, and cerebral white matter lesions. It also discusses the neuroprotective roles of microglia during recovery from subarachnoid hemorrhage and therapeutic advances aimed at modulating microglial function after subarachnoid hemorrhage. Currently, microglia in subarachnoid hemorrhage are targeted with TLR inhibitors, nuclear factor-κB and STAT3 pathway inhibitors, glycine/tyrosine kinases, NLRP3 signaling pathway inhibitors, Gasdermin D inhibitors, vincristine receptor α receptor agonists, ferroptosis inhibitors, genetic modification techniques, stem cell therapies, and traditional Chinese medicine. However, most of these are still being evaluated at the laboratory stage. More clinical studies and data on subarachnoid hemorrhage are required to improve the treatment of subarachnoid hemorrhage.

The piper at the gates of brain: A systematic review of surface modification strategies on lipid nanoparticles to overcome the Blood-Brain-Barrier

The Blood-Brain Barrier (BBB) significantly impedes drug delivery to the central nervous system. Nanotechnology, especially surface-functionalized lipid nanoparticles, offers innovative approaches to overcome this barrier. However, choosing an effective functionalization strategy is challenging due to the lack of detailed comparative analysis in current literature. Our systematic review examined various functionalization strategies and their impact on BBB permeability from 2041 identified articles, of which 80 were included for data extraction. Peptides were the most common modification (18) followed by mixed strategies (12) proteins (9), antibodies (7), and other strategies (8). Interestingly, 26 studies showed BBB penetration with unmodified or modified nanoparticles using commonly applied strategies such as PEGylation or surfactant addition. Statistical analysis across 42 studies showed correlation between higher in vivo permeation improvements and nanoparticle type, size, and functionalization category. The highest ratios were found for nanostructured lipid carriers or biomimetic systems, in studies with particle sizes under 150 nm, and in those applying mixed functionalization strategies. The interstudy heterogeneity we observed highlights the importance of adopting standardized evaluation protocols to enhance comparability. Our systematic review aims to provide a comparative insight and identify future research directions in the development of more effective lipid nanoparticle systems for drug delivery to the brain to help improve the treatment of neurological and psychiatric disorders and brain tumours.

Real-time monitoring of a 3D blood-brain barrier model maturation and integrity with a sensorized microfluidic device

A significant challenge in the treatment of central nervous system (CNS) disorders is represented by the presence of the blood-brain barrier (BBB), a highly selective membrane that regulates molecular transport and restricts the passage of pathogens and therapeutic compounds. Traditional in vivo models are constrained by high costs, lengthy experimental timelines, ethical concerns, and interspecies variations. In vitro models, particularly microfluidic BBB-on-a-chip devices, have been developed to address these limitations. These advanced models aim to more accurately replicate human BBB conditions by incorporating human cells and physiological flow dynamics. In this framework, here we developed an innovative microfluidic system that integrates thin-film electrodes for non-invasive, real-time monitoring of BBB integrity using electrochemical impedance spectroscopy (EIS). EIS measurements showed frequency-dependent impedance changes, indicating BBB integrity and distinguishing well-formed from non-mature barriers. The data from EIS monitoring was confirmed by permeability assays performed with a fluorescence tracer. The model incorporates human endothelial cells in a vessel-like arrangement to mimic the vascular component and three-dimensional cell distribution of human astrocytes and microglia to simulate the parenchymal compartment. By modeling the BBB-on-a-chip with an equivalent circuit, a more accurate trans-endothelial electrical resistance (TEER) value was extracted. The device demonstrated successful BBB formation and maturation, confirmed through live/dead assays, immunofluorescence and permeability assays. Computational fluid dynamics (CFD) simulations confirmed that the device mimics in vivo shear stress conditions. Drug crossing assessment was performed with two chemotherapy drugs: doxorubicin, with a known poor BBB penetration, and temozolomide, conversely a specific drug for CNS disorders and able to cross the BBB, to validate the model predictive capability for drug crossing behavior. The proposed sensorized microfluidic device represents a significant advancement in BBB modeling, offering a versatile platform for CNS drug development, disease modeling, and personalized medicine.

The enigma of mitochondrial epigenetic alterations in air pollution-induced neurodegenerative diseases

The incidence of neurodegenerative diseases is a growing concern worldwide, affecting individuals from diverse backgrounds. Although these pathologies are primarily associated with aging and genetic susceptibility, their severity varies among the affected population. Numerous studies have indicated air pollution as a significant contributor to the increasing prevalence of neurodegeneration. Cohort studies have provided compelling evidence of the association between prolonged exposure to different air toxicants and cognitive decline, behavioural deficits, memory impairment, and overall neuronal health deterioration. Furthermore, molecular research has revealed that air pollutants can disrupt the body's protective mechanisms, participate in neuroinflammatory pathways, and cause neuronal epigenetic modifications. The mitochondrial epigenome is particularly interesting to the scientific community due to its potential to significantly impact our understanding of neurodegenerative diseases' pathogenesis and their release in the peripheral circulation. While protein hallmarks have been extensively studied, the possibility of using circulating epigenetic signatures, such as methylated DNA fragments, miRNAs, and genome-associated factors, as diagnostic tools and therapeutic targets requires further groundwork. The utilization of circulating epigenetic signatures holds promise for developing novel prognostic strategies, creating paramount point-of-care devices for disease diagnosis, identifying therapeutic targets, and developing clinical data-based disease models utilizing multi-omics technologies and artificial intelligence, ultimately mitigating the threat and prevalence of neurodegeneration.

Short-chain fatty acid on blood-brain barrier and glial function in ischemic stroke

Stroke is the second most common cause of death and one of the most common causes of disability worldwide. The intestine is home to several microorganisms that fulfill essential functions for the natural and physiological functioning of the human body. There is an interaction between the central nervous system (CNS) and the gastrointestinal system that enables bidirectional communication between them, the so-called gut-brain axis. Based on the gut-brain axis, there is evidence of a link between the gut microbiota and the regulation of microglial functions through glial activation. This interaction is partly due to the immunological properties of the microbiota and its connection with the CNS, such that metabolites produced by the microbiota can cross the gut barrier, enter the bloodstream and reach the CNS and significantly affect microglia, astrocytes and other cells of the immune system. Studies addressing the effects of short-chain fatty acids (SCFAs) on glial function and the BBB in ischemic stroke are still scarce. Therefore, this review aims to stimulate the investigation of these associations, as well as to generate new studies on this topic that can clarify the role of SCFAs after stroke in a more robust manner.

The role of integrins in brain health and neurodegenerative diseases

Integrins are heterodimeric membrane proteins expressed on the surface of most cells. They mediate adhesion and signaling processes relevant for a wealth of physiological processes, including nervous system development and function. Interestingly, integrins are also recognized therapeutic targets for inflammatory diseases, such as multiple sclerosis. Here, we discuss the role of integrins in brain development and function, as well as in neurodegenerative diseases affecting the brain (Alzheimer's disease, multiple sclerosis, stroke). Furthermore, we discuss therapeutic targeting of these adhesion receptors in inflammatory diseases of the brain.

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.

Neuroprotective effects of salvianolic acids combined with Panax notoginseng saponins in cerebral ischemia/reperfusion rats concerning the neurovascular unit and trophic coupling

BACKGROUND

The neurovascular unit (NVU) and neurovascular trophic coupling (NVTC) play a key regulatory role in brain injury caused by ischemic stroke. Salvianolic acids (SAL) and Panax notoginseng saponins (PNS) are widely used in China to manage ischemic stroke. Neuroprotective effects of SAL and PNS, either taken alone or in combination, were examined in this research.

METHODS

Wistar rats were randomly divided into the following groups: Sham group (Sham), cerebral ischemia/reperfusion group (I/R), I/R with SAL group (SAL), I/R with PNS group (PNS), I/R with SAL combined with PNS (SAL + PNS), and I/R with edaravone group (EDA). Treatment was administered once daily for two days after modeling of middle cerebral artery occlusion/reperfusion (MCAO/R).

RESULTS

Compared with the I/R group, SAL, PNS, or SAL + PNS treatment reduced infarct size, improved neurological deficit score, reduced Evans blue extravasation, increased expression of CD31 and tight junction proteins (TJs), including zonula occludens-1 (ZO-1), zonula occludens-2 (ZO-2), and junctional adhesion molecule-1 (JAM-1). Furthermore, SAL, PNS, or SAL + PNS suppressed the activations of microglia and astrocyte and led to the amelioration of neuron and pericyte injury. Treatment also inhibited NVU dissociation of GFAP/PDGFRβ and Collagen IV/GFAP while upregulated the expression level of BDNF/TrkB and BDNF/NeuN.

CONCLUSIONS

SAL and PNS have significantly remedied structural and functional disorders of NVU and NVTC in I/R injury. These effects were more pronounced when SAL and PNS were combined than when used separately.

Structural and Functional Dysregulation of the Brain Endothelium in HIV Infection and Substance Abuse

Blood-brain barrier (BBB) injury and dysfunction following infection with the human immunodeficiency virus (HIV) enables viral entry into the brain, infection of resident brain cells, neuronal injury and subsequent neurodegeneration leading to HIV-associated neurocognitive disorders (HAND). Although combination antiretroviral therapy has significantly reduced the incidence and prevalence of acquired immunodeficiency syndrome and increased the life expectancy of people living with HIV, the prevalence of HAND remains high. With aging of people living with HIV associated with increased comorbidities, the prevalence of HIV-related central nervous system (CNS) complications is expected to remain high. Considering the principal role of the brain endothelium in HIV infection of the CNS and HAND, the purpose of this manuscript is to review the current literature on the pathobiology of the brain endothelium structural and functional dysregulation in HIV infection, including in the presence of HIV-1 and viral proteins (gp120, Tat, Nef, and Vpr). We summarize evidence from human and animal studies, in vitro studies, and associated mechanisms. We further summarize evidence of synergy or lack thereof between commonly abused substances (cocaine, methamphetamine, alcohol, tobacco, opioids, and cannabinoids) and HIV- or viral protein-induced BBB injury and dysfunction.

Oligomeric Tau-induced oxidative damage and functional alterations in cerebral endothelial cells: Role of RhoA/ROCK signaling pathway

Despite of yet unknown mechanism, microvascular deposition of oligomeric Tau (oTau) has been implicated in alteration of the Blood-Brain Barrier (BBB) function in Alzheimer's disease (AD) brains. In this study, we employed an in vitro BBB model using primary mouse cerebral endothelial cells (CECs) to investigate the mechanism underlying the effects of oTau on BBB function. We found that exposing CECs to oTau induced oxidative stress through NADPH oxidase, increased oxidative damage to proteins, decreased proteasome activity, and expressions of tight junction (TJ) proteins including occludin, zonula occludens-1 (ZO-1) and claudin-5. These effects were suppressed by the pretreatment with Fasudil, a RhoA/ROCK signaling inhibitor. Consistent with the biochemical alterations, we found that exposing the basolateral side of CECs to oTau in the BBB model disrupted the integrity of the BBB, as indicated by an increase in FITC-dextran transport across the model, and a decrease in trans endothelial electrical resistance (TEER). oTau also increased the transmigration of peripheral blood mononuclear cells (PBMCs) in the BBB model. These functional alterations in the BBB induced by oTau were also suppressed by Fasudil. Taken together, our findings suggest that targeting the RhoA/ROCK pathway can be a potential therapeutic strategy to maintain BBB function in AD.

circRNAs as Epigenetic Regulators of Integrity in Blood-Brain Barrier Architecture: Mechanisms and Therapeutic Strategies in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease leading to progressive demyelination and neuronal loss, with extensive neurological symptoms. As one of the most widespread neurodegenerative disorders, with an age onset of about 30 years, it turns out to be a socio-health and economic issue, thus necessitating therapeutic interventions currently unavailable. Loss of integrity in the blood-brain barrier (BBB) is one of the distinct MS hallmarks. Brain homeostasis is ensured by an endothelial cell-based monolayer at the interface between the central nervous system (CNS) and systemic bloodstream, acting as a selective barrier. MS results in enhanced barrier permeability, mainly due to the breakdown of tight (TJs) and adherens junctions (AJs) between endothelial cells. Specifically, proinflammatory mediator release causes failure in cytoplasmic exposure of junctions, resulting in compromised BBB integrity that enables blood cells to cross the barrier, establishing iron deposition and neuronal impairment. Cells with a compromised cytoskeletal protein network, fiber reorganization, and discontinuous junction structure can occur, resulting in BBB dysfunction. Recent investigations on spatial transcriptomics have proven circularRNAs (circRNAs) to be powerful multi-functional molecules able to epigenetically regulate transcription and structurally support proteins. In the present review, we provide an overview of the recent role ascribed to circRNAs in maintaining BBB integrity/permeability via cytoskeletal stability. Increased knowledge of the mechanisms responsible for impairment and circRNA's role in driving BBB damage and dysfunction might be helpful for the recognition of novel therapeutic targets to overcome BBB damage and unrestrained neurodegeneration.

Exosomes as therapeutic and drug delivery vehicle for neurodegenerative diseases

Neurodegenerative disorders are complex, progressive, and life-threatening. They cause mortality and disability for millions of people worldwide. Appropriate treatment for neurodegenerative diseases (NDs) is still clinically lacking due to the presence of the blood-brain barrier (BBB). Developing an effective transport system that can cross the BBB and enhance the therapeutic effect of neuroprotective agents has been a major challenge for NDs. Exosomes are endogenous nano-sized vesicles that naturally carry biomolecular cargoes. Many studies have indicated that exosome content, particularly microRNAs (miRNAs), possess biological activities by targeting several signaling pathways involved in apoptosis, inflammation, autophagy, and oxidative stress. Exosome content can influence cellular function in healthy or pathological ways. Furthermore, since exosomes reflect the features of the parental cells, their cargoes offer opportunities for early diagnosis and therapeutic intervention of diseases. Exosomes have unique characteristics that make them ideal for delivering drugs directly to the brain. These characteristics include the ability to pass through the BBB, biocompatibility, stability, and innate targeting properties. This review emphasizes the role of exosomes in alleviating NDs and discusses the associated signaling pathways and molecular mechanisms. Furthermore, the unique biological features of exosomes, making them a promising natural transporter for delivering various medications to the brain to combat several NDs, are also discussed.

Interplay between microglia and environmental risk factors in Alzheimer's disease

Alzheimer's disease, among the most common neurodegenerative disorders, is characterized by progressive cognitive impairment. At present, the Alzheimer's disease main risk remains genetic risks, but major environmental factors are increasingly shown to impact Alzheimer's disease development and progression. Microglia, the most important brain immune cells, play a central role in Alzheimer's disease pathogenesis and are considered environmental and lifestyle "sensors." Factors like environmental pollution and modern lifestyles (e.g., chronic stress, poor dietary habits, sleep, and circadian rhythm disorders) can cause neuroinflammatory responses that lead to cognitive impairment via microglial functioning and phenotypic regulation. However, the specific mechanisms underlying interactions among these factors and microglia in Alzheimer's disease are unclear. Herein, we: discuss the biological effects of air pollution, chronic stress, gut microbiota, sleep patterns, physical exercise, cigarette smoking, and caffeine consumption on microglia; consider how unhealthy lifestyle factors influence individual susceptibility to Alzheimer's disease; and present the neuroprotective effects of a healthy lifestyle. Toward intervening and controlling these environmental risk factors at an early Alzheimer's disease stage, understanding the role of microglia in Alzheimer's disease development, and targeting strategies to target microglia, could be essential to future Alzheimer's disease treatments.

The Role of Glutamate and Blood-Brain Barrier Disruption as a Mechanistic Link between Epilepsy and Depression

Epilepsy is associated with substantial neuropsychiatric impairments that persist long after the onset of the condition, significantly impacting quality of life. The goal of this review was to uncover how the pathological consequences of epilepsy, such as excessive glutamate release and a disrupted blood-brain barrier (BBB), contribute to the emergence of neuropsychiatric disorders. We hypothesize that epilepsy induces a dysfunctional BBB through hyperexcitation, which then further amplifies post-ictal glutamate levels and, thus, triggers neurodegenerative and neuropsychiatric processes. This review identifies the determinants of glutamate concentration levels in the brain and explores potential therapeutic interventions that restore BBB integrity. Our focus on therapeutic BBB restoration is guided by the premise that it may improve glutamate regulation, consequently mitigating the neurotoxicity that contributes to the onset of neuropsychiatric symptoms.

Neuroinflammation in Glioblastoma: Progress and Perspectives

Glioblastoma is the most common and malignant primary brain tumor, with high morbidity and mortality. Despite an aggressive, multimodal treatment regimen, including surgical resection followed by chemotherapy and radiotherapy, the prognosis of glioblastoma patients remains poor. One formidable challenge to advancing glioblastoma therapy is the complexity of the tumor microenvironment. The tumor microenvironment of glioblastoma is a highly dynamic and heterogeneous system that consists of not only cancerous cells but also various resident or infiltrating inflammatory cells. These inflammatory cells not only provide a unique tumor environment for glioblastoma cells to develop and grow but also play important roles in regulating tumor aggressiveness and treatment resistance. Targeting the tumor microenvironment, especially neuroinflammation, has increasingly been recognized as a novel therapeutic approach in glioblastoma. In this review, we discuss the components of the tumor microenvironment in glioblastoma, focusing on neuroinflammation. We discuss the interactions between different tumor microenvironment components as well as their functions in regulating glioblastoma pathogenesis and progression. We will also discuss the anti-tumor microenvironment interventions that can be employed as potential therapeutic targets.

Nanozymes: Potential Therapies for Reactive Oxygen Species Overproduction and Inflammation in Ischemic Stroke and Traumatic Brain Injury

Nanozymes, which can selectively scavenge reactive oxygen species (ROS), have recently emerged as promising candidates for treating ischemic stroke and traumatic brain injury (TBI) in preclinical models. ROS overproduction during the early phase of these diseases leads to oxidative brain damage, which has been a major cause of mortality worldwide. However, the clinical application of ROS-scavenging enzymes is limited by their short in vivo half-life and inability to cross the blood-brain barrier. Nanozymes, which mimic the catalytic function of natural enzymes, have several advantages, including cost-effectiveness, high stability, and easy storage. These advantages render them superior to natural enzymes for disease diagnosis and therapeutic interventions. This review highlights recent advancements in nanozyme applications for ischemic stroke and TBI, emphasizing their potential to mitigate the detrimental effect of ROS overproduction, oxidative brain damage, inflammation, and blood-brain barrier compromise. Therefore, nanozymes represent a promising treatment modality for ROS overproduction conditions in future medical practices.

Discovery of a Novel Dual Targeting Peptide for Human Glioma: From In Silico Simulation to Acting as Targeting Ligand

Purpose

Receptor-mediated transcytosis (RMT) is a more specific, highly efficient, and reliable approach to crossing the blood-brain-barrier (BBB) and releasing the therapeutic cargos into the brain parenchyma.

Methods

Here, we introduced and characterized a human/mouse-specific novel leptin-derived peptide using in silico, in vitro and in vivo experiments.

Results

Based on the bioinformatics analysis and molecular dynamics (MD) simulation, a 14 amino acid peptide sequence (LDP 14) was introduced and its interaction with leptin-receptor (ObR) was analyzed in comparison with an well known leptin-derived peptide, Lep 30. MD simulation data revealed a significant stable interaction between ligand binding domains (LBD) of ObR with LDP 14. Analyses demonstrated suitable cellular uptake of LDP 14 alone and its derivatives (LDP 14-modified G4 PAMAM dendrimer and LDP 14-modified G4 PAMAM/pEGFP-N1 plasmid complexes) via ObR, energy and species dependent manner (preferred uptake by human/mouse cell lines compared to rat cell line). Importantly, our findings illustrated that the entry of LDP 14-modified dendrimers in hBCEC-D3 cells not only is not affected by protein corona (PC) formation, as the main reason for diminishing the cellular uptake, but also PC per se can enhance uptake rate. Finally, fluorescein labeled LDP 14-modified G4 PAMAM dendrimers efficiently accumulated in the mice brain with lower biodistribution in other organs, in our in vivo study.

Conclusion

LDP 14 introduced as a novel and highly efficient ligand, which can be used for drugs/genes delivery to brain tissue in different central nervous system (CNS) disorders.

An Overview on the Physiopathology of the Blood-Brain Barrier and the Lipid-Based Nanocarriers for Central Nervous System Delivery

The state of well-being and health of our body is regulated by the fine osmotic and biochemical balance established between the cells of the different tissues, organs, and systems. Specific districts of the human body are defined, kept in the correct state of functioning, and, therefore, protected from exogenous or endogenous insults of both mechanical, physical, and biological nature by the presence of different barrier systems. In addition to the placental barrier, which even acts as a linker between two different organisms, the mother and the fetus, all human body barriers, including the blood-brain barrier (BBB), blood-retinal barrier, blood-nerve barrier, blood-lymph barrier, and blood-cerebrospinal fluid barrier, operate to maintain the physiological homeostasis within tissues and organs. From a pharmaceutical point of view, the most challenging is undoubtedly the BBB, since its presence notably complicates the treatment of brain disorders. BBB action can impair the delivery of chemical drugs and biopharmaceuticals into the brain, reducing their therapeutic efficacy and/or increasing their unwanted bioaccumulation in the surrounding healthy tissues. Recent nanotechnological innovation provides advanced biomaterials and ad hoc customized engineering and functionalization methods able to assist in brain-targeted drug delivery. In this context, lipid nanocarriers, including both synthetic (liposomes, solid lipid nanoparticles, nanoemulsions, nanostructured lipid carriers, niosomes, proniosomes, and cubosomes) and cell-derived ones (extracellular vesicles and cell membrane-derived nanocarriers), are considered one of the most successful brain delivery systems due to their reasonable biocompatibility and ability to cross the BBB. This review aims to provide a complete and up-to-date point of view on the efficacy of the most varied lipid carriers, whether FDA-approved, involved in clinical trials, or used in in vitro or in vivo studies, for the treatment of inflammatory, cancerous, or infectious brain diseases.

History of the Development of Knowledge about the Neuroendocrine Control of Ovulation-Recent Knowledge on the Molecular Background

The physiology of reproduction has been of interest to researchers for centuries. The purpose of this work is to review the development of our knowledge on the neuroendocrine background of the regulation of ovulation. We first describe the development of the pituitary gland, the structure of the median eminence (ME), the connection between the hypothalamus and the pituitary gland, the ovarian and pituitary hormones involved in ovulation, and the pituitary cell composition. We recall the pioneer physiological and morphological investigations that drove development forward. The description of the supraoptic-paraventricular magnocellular and tuberoinfundibular parvocellular systems and recognizing the role of the hypophysiotropic area were major milestones in understanding the anatomical and physiological basis of reproduction. The discovery of releasing and inhibiting hormones, the significance of pulse and surge generators, the pulsatile secretion of the gonadotropin-releasing hormone (GnRH), and the subsequent pulsatility of luteinizing (LH) and follicle-stimulating hormones (FSH) in the human reproductive physiology were truly transformative. The roles of three critical neuropeptides, kisspeptin (KP), neurokinin B (NKB), and dynorphin (Dy), were also identified. This review also touches on the endocrine background of human infertility and assisted fertilization.

A Big Prospect for Hydrogel Nano-System in Glioma

Patients diagnosed with glioma typically face a limited life expectancy (around 15 months on average), a bleak prognosis, and a high likelihood of recurrence. As such, glioma is recognized as a significant form of malignancy. Presently, the treatment options for glioma include traditional approaches such as surgery, chemotherapy, and radiotherapy. Regrettably, the efficacy of these treatments has been less than optimal. Nevertheless, a promising development in glioma treatment lies in the use of hydrogel nano-systems as sophisticated delivery systems. These nano-systems have demonstrated exceptional therapeutic effects in the treatment of glioma by various responsive ways, including temperature-response, pH-response, liposome-response, ROS-response, light-response, and enzyme-response. This study seeks to provide a comprehensive summary of both the therapeutic application of hydrogel nano-systems in managing glioma and the underlying immune action mechanisms.

Cerebral endothelial cells mediated enhancement of brain pericyte number and migration in oxygen-glucose deprivation involves the HIF-1α/PDGF-β signaling

The present study focused on whether hypoxia-inducible factor-1alpha (HIF-1α) and platelet-derived factor-beta (PDGF-β) are involved in the crosstalk between brain microvascular endothelial cells (BMECs) and brain vascular pericytes (BVPs) under ischaemic-hypoxic conditions. Mono-cultures or co-cultures of BVPs and BMECs were made for the construction of the blood-brain barrier (BBB) model in vitro and then exposed to control and oxygen-glucose deprivation (OGD) conditions. BBB injury was determined by assessing the ability, apoptosis, and migration of BVPs and the transendothelial electrical resistance and horseradish peroxidase permeation of BMECs. Relative mRNA and protein levels of HIF-1α and PDGF-β, as well as tight junction proteins ZO-1 and claudin-5 were analyzed by western blotting, reverse transcription quantitative PCR, and/or immunofluorescence staining. Dual-luciferase reporter assays assessed the relationship between PDGF-β and HIF-1α. Co-culturing with BMECs alleviated OGD-induced reduction in BVP viability, elevation in BVP apoptosis, and repression in BVP migration. Co-culturing with BVPs protected against OGD-induced impairment on BMEC permeability. OGD-induced HIF-1α upregulation enhanced PDGF-β expression in mono-cultured BMECs and co-cultured BMECs with BVPs. Knockdown of HIF-1α impaired the effect of BMECs on BVPs under OGD conditions, and PDGFR-β silencing in BVPs blocked the crosstalk between BMECs and BVPs under OGD conditions. The crosstalk between BMECs and BVPs was implicated in OGD-induced BBB injury through the HIF-1α/PDGF-β signaling.

Cubosomes as versatile lipid nanocarriers for neurological disorder therapeutics: a comprehensive review

Cubosomes are novel vesicular drug delivery systems with lipidic liquid crystal nanoparticles formed of predetermined proportions of amphiphilic lipids. They have a honeycomb-like structure and are thermodynamically stable. These bicontinuous lipid layers are separated into two water-based channels internally that can be used by various bioactive substances, including drugs, proteins, and peptides. This complex structure is responsible for its high drug-loading capacity. Cubosomes are thought to be promising vehicles for various routes of administration because of their extraordinary characteristics, including bioadhesion, the capacity to encapsulate hydrophilic, and hydrophobic, as well as amphiphilic substances, high resistance to environmental stress, and their ability to achieve controlled release through modification. One of the essential elements for improving patient compliance is the ability of these well-defined nano-drug delivery systems to boost the effectiveness of targeting while lowering the side effects/toxicities of payloads. The large internal surface area, a sufficiently uncomplicated fabrication procedure, and biodegradability make it an attractive nano lipid carrier for drug delivery. This review outlines the recent advancement of cubosomes for managing various neurological disorders, highlighting their potential in this field.

The effectiveness of hesperidin on bisphenol A-induced spinal cord toxicity in a diabetic rat model

The potential health risks of bisphenol A (BS) and diabetes (DI) has sparked public concern due to be ubiquitous worldwide. The purpose of this study was to investigate the detrimental impact of BS (200 mg/kg) on the spinal cord tissue in a rat diabetic model. We also evaluated the antioxidant capacity of hesperidin (HS) (100 mg/kg) on spinal cord in BS-treated diabetic rat. Seventy male Wistar albino rats, weighing 180-230 g and 8 weeks old, were randomly chosen, and assigned into seven groups of 10 rats: Control (KON), BS, DI, BS + DI, HS + BS, HS + DI, HS + BS + DI. At the end of the 14-day experimental period, all samples were examined using stereological, biochemical, and histopathological techniques. Our biochemical findings revealed that the SOD level was significantly lower in the BS, DI, and BS + DI groups compared to the KON group (p < 0.05). Compared to the KON group, there was a significant decrease in the number of motor neurons and an increase in the mean volume of central canals in the BS, DI, and BS + DI groups (p < 0.05). In the HS + BC group than the BS group and in the HS + DI group than the DI group, SOD activity and the number of motor neurons were significantly higher; also, the mean volume of spinal central canal was significantly lower (p < 0.05). The novel findings gathered from the histopathological assessment supported our quantitative results. Our speculation was that the exposure to BS and DI was the main cause of neurological alteration in the spinal cord tissues. The administration of HS had the therapeutic potential to mitigate spinal cord abnormalities resulting from BS and DI. However, HS supplementation did not alleviate spinal cord complications in BS-treated diabetic rats.

Neutrophils in glioma microenvironment: from immune function to immunotherapy

Glioma is a malignant tumor of the central nervous system (CNS). Currently, effective treatment options for gliomas are still lacking. Neutrophils, as an important member of the tumor microenvironment (TME), are widely distributed in circulation. Recently, the discovery of cranial-meningeal channels and intracranial lymphatic vessels has provided new insights into the origins of neutrophils in the CNS. Neutrophils in the brain may originate more from the skull and adjacent vertebral bone marrow. They cross the blood-brain barrier (BBB) under the action of chemokines and enter the brain parenchyma, subsequently migrating to the glioma TME and undergoing phenotypic changes upon contact with tumor cells. Under glycolytic metabolism model, neutrophils show complex and dual functions in different stages of cancer progression, including participation in the malignant progression, immune suppression, and anti-tumor effects of gliomas. Additionally, neutrophils in the TME interact with other immune cells, playing a crucial role in cancer immunotherapy. Targeting neutrophils may be a novel generation of immunotherapy and improve the efficacy of cancer treatments. This article reviews the molecular mechanisms of neutrophils infiltrating the central nervous system from the external environment, detailing the origin, functions, classifications, and targeted therapies of neutrophils in the context of glioma.

Harnessing the potential of nanoengineered siRNAs carriers for target responsive glioma therapy: Recent progress and future opportunities

Past scientific testimonials in the field of glioma research, the deadliest tumor among all brain cancer types with the life span of 10-15 months after diagnosis is considered as glioblastoma multiforme (GBM). Even though the availability of treatment options such as chemotherapy, radiotherapy, and surgery, are unable to completely cure GBM due to tumor microenvironment complexity, intrinsic cellular signalling, and genetic mutations which are involved in chemoresistance. The blood-brain barrier is accountable for restricting drugs entry at the tumor location and related biological challenges like endocytic degradation, short systemic circulation, and insufficient cellular penetration lead to tumor aggression and progression. The above stated challenges can be better mitigated by small interfering RNAs (siRNA) by knockdown genes responsible for tumor progression and resistance. However, siRNA encounters with challenges like inefficient cellular transfection, short circulation time, endogenous degradation, and off-target effects. The novel functionalized nanocarrier approach in conjunction with biological and chemical modification offers an intriguing potential to address challenges associated with the naked siRNA and efficiently silence STAT3, coffilin-1, EGFR, VEGF, SMO, MGMT, HAO-1, GPX-4, TfR, LDLR and galectin-1 genes in GBM tumor. This review highlights the nanoengineered siRNA carriers, their recent advancements, future perspectives, and strategies to overcome the systemic siRNA delivery challenges for glioma treatment.

Revolutionizing neurotherapeutics: blood-brain barrier-on-a-chip technologies for precise drug delivery

Introduction

The blood-brain barrier (BBB) is a critical neurovascular unit regulating substances' passage from the bloodstream to the brain. Its selective permeability poses significant challenges in drug delivery for neurological disorders. Conventional methods often fail due to the BBB's complex structure.

Aim

The study aims to shed light on their pivotal role in revolutionizing neurotherapeutics and explores the transformative potential of BBB-on-a-Chip technologies in drug delivery research to comprehensively review BBB-on-a-chip technologies, focusing on their design, and substantiate advantages over traditional models.

Methods

A detailed analysis of existing literature and experimental data pertaining to BBB-on-a-Chip technologies was conducted. Various models, their physiological relevance, and innovative design considerations were examined through databases like Scopus, EbscoHost, PubMed Central, and Medline. Case studies demonstrating enhanced drug transport through BBB-on-a-Chip models were also reviewed, highlighting their potential impact on neurological disorders.

Results

BBB-on-a-Chip models offer a revolutionary approach, accurately replicating BBB properties. These microphysiological systems enable high-throughput screening, real-time monitoring of drug transport, and precise localization of drugs. Case studies demonstrate their efficacy in enhancing drug penetration, offering potential therapies for diseases like Parkinson's and Alzheimer's.

Conclusion

BBB-on-a-Chip models represent a transformative milestone in drug delivery research. Their ability to replicate BBB complexities, offer real-time monitoring, and enhance drug transport holds immense promise for neurological disorders. Continuous research and development are imperative to unlock BBB-on-a-Chip models' full potential, ushering in a new era of targeted, efficient, and safer drug therapies for challenging neurological conditions.

Emerging Role of ABC Transporters in Glia Cells in Health and Diseases of the Central Nervous System

ATP-binding cassette (ABC) transporters play a crucial role for the efflux of a wide range of substrates across different cellular membranes. In the central nervous system (CNS), ABC transporters have recently gathered significant attention due to their pivotal involvement in brain physiology and neurodegenerative disorders, such as Alzheimer's disease (AD). Glial cells are fundamental for normal CNS function and engage with several ABC transporters in different ways. Here, we specifically highlight ABC transporters involved in the maintenance of brain homeostasis and their implications in its metabolic regulation. We also show new aspects related to ABC transporter function found in less recognized diseases, such as Huntington's disease (HD) and experimental autoimmune encephalomyelitis (EAE), as a model for multiple sclerosis (MS). Understanding both their impact on the physiological regulation of the CNS and their roles in brain diseases holds promise for uncovering new therapeutic options. Further investigations and preclinical studies are warranted to elucidate the complex interplay between glial ABC transporters and physiological brain functions, potentially leading to effective therapeutic interventions also for rare CNS disorders.

Blood-brain barrier biomarkers

The blood-brain barrier (BBB) is a dynamic interface that regulates the exchange of molecules and cells between the brain parenchyma and the peripheral blood. The BBB is mainly composed of endothelial cells, astrocytes and pericytes. The integrity of this structure is essential for maintaining brain and spinal cord homeostasis and protection from injury or disease. However, in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, and multiple sclerosis, the BBB can become compromised thus allowing passage of molecules and cells in and out of the central nervous system parenchyma. These agents, however, can serve as biomarkers of BBB permeability and neuronal damage, and provide valuable information for diagnosis, prognosis and treatment. Herein, we provide an overview of the BBB and changes due to aging, and summarize current knowledge on biomarkers of BBB disruption and neurodegeneration, including permeability, cellular, molecular and imaging biomarkers. We also discuss the challenges and opportunities for developing a biomarker toolkit that can reliably assess the BBB in physiologic and pathophysiologic states.

TAK-3 Inhibits Lipopolysaccharide-Induced Neuroinflammation in Traumatic Brain Injury Rats Through the TLR-4/NF-κB Pathway

Purpose

The activation of the inflammatory response is regarded as a pivotal factor in the pathogenesis of TBI. Central nervous system infection often leads to the exacerbation of neuroinflammation following TBI, primarily caused by Gram-negative bacteria. This study aims to elucidate the effects of the novel anti-inflammatory drug TAK-3 on LPS-induced neuroinflammation in TBI rats.

Methods

In conjunction with the rat controlled cortical impact model, we administered local injections of Lipopolysaccharide to the impact site. Subsequently, interventions were implemented through intraperitoneal injections of TAK-3 and NF-κB activitor2 to modulate the TLR4/NF-κB axis The impact of LPS on neurological function was assessed using mNSS, open field test, and brain water content measurement. Inflammatory markers, including TNF-α, IL-1β, IL-6 and IL-10 were assessed to evaluate the condition of neuritis by Elisa. The activation of the TLR-4/NF-κB signaling pathway was detected by immunofluorescence staining and Western blot to assess the anti-inflammatory effects of TAK-3.

Results

The administration of LPS exacerbated neurological damage in rats with TBI, as evidenced by a reduction in motor activity and an increase in anxiety-like behavior. Furthermore, LPS induced disruption of the blood-brain barrier integrity and facilitated the development of brain edema. The activation of microglia and astrocytes by LPS at the cellular and molecular levels has been demonstrated to induce a significant upregulation of neuroinflammatory factors. The injection of TAK-3 attenuated the neuroinflammatory response induced by LPS.

Conclusion

The present study highlights the exacerbating effects of LPS on neuroinflammation in TBI through activation of the TLR-4/NF-κB signaling pathway. TAK-3 can modulate the activity of this signaling axis, thereby attenuating neuroinflammation and ultimately reducing brain tissue damage.

Circadian Rhythms of the Blood-Brain Barrier and Drug Delivery

The blood-brain barrier (BBB) is a critical interface separating the central nervous system from the peripheral circulation, ensuring brain homeostasis and function. Recent research has unveiled a profound connection between the BBB and circadian rhythms, the endogenous oscillations synchronizing biological processes with the 24-hour light-dark cycle. This review explores the significance of circadian rhythms in the context of BBB functions, with an emphasis on substrate passage through the BBB. Our discussion includes efflux transporters and the molecular timing mechanisms that regulate their activities. A significant focus of this review is the potential implications of chronotherapy, leveraging our knowledge of circadian rhythms for improving drug delivery to the brain. Understanding the temporal changes in BBB can lead to optimized timing of drug administration, to enhance therapeutic efficacy for neurological disorders while reducing side effects. By elucidating the interplay between circadian rhythms and drug transport across the BBB, this review offers insights into innovative therapeutic interventions.

Silica Nanoparticles Decrease Glutamate Uptake in Blood-Brain Barrier Components

Glutamate is the major excitatory amino acid in the vertebrate brain, playing an important role in most brain functions. It exerts its activity through plasma membrane receptors and transporters, expressed both in neurons and glia cells. Overstimulation of neuronal glutamate receptors is linked to cell death in a process known as excitotoxicity, that is prevented by the efficient removal of the neurotransmitter through glutamate transporters enriched in the glia plasma membrane and in the components of the blood-brain barrier (BBB). Silica nanoparticles (SiO2-NPs) have been widely used in biomedical applications and directed to enter the circulatory system; however, little is known about the potential adverse effects of SiO2-NPs exposure on the BBB transport systems that support the critical isolation function between the central nervous system (CNS) and the peripheral circulation. In this contribution, we investigated the plausible SiO2-NPs-mediated disruption of the glutamate transport system expressed by BBB cell components. First, we evaluated the cytotoxic effect of SiO2-NPs on human brain endothelial (HBEC) and Uppsala 87 Malignant glioma (U-87MG) cell lines. Transport kinetics were evaluated, and the exposure effect of SiO2-NPs on glutamate transport activity was determined in both cell lines. Exposure of the cells to different SiO2-NP concentrations (0.4, 4.8, 10, and 20 µg/ml) and time periods (3 and 6 h) did not affect cell viability. We found that the radio-labeled D-aspartate ([3H]-D-Asp) uptake is mostly sodium-dependent, and downregulated by its own substrate (glutamate). Furthermore, SiO2-NPs exposure on endothelial and astrocytes decreases [3H]-D-Asp uptake in a dose-dependent manner. Interestingly, a decrease in the transporter catalytic efficiency, probably linked to a diminution in the affinity of the transporter, was detected upon SiO2-NPs. These results favor the notion that exposure to SiO2-NPs could disrupt BBB function and by these means shed some light into our understanding of the deleterious effects of air pollution on the CNS.

NeuroClick: software for mimicking click reaction to generate drug-like molecules permeating the blood-brain barrier

Background: Traditional methods for chemical library generation in virtual screening often impose limitations on the accessible chemical space or produce synthetically irrelevant structures. Incorporating common chemical reactions into generative algorithms could offer significant benefits. Materials & methods: In this study, we developed NeuroClick, a graphical user interface software designed to perform in silico azide-alkyne cycloaddition, a widely utilized synthetic approach in modern medicinal chemistry. Results & conclusion: NeuroClick facilitates the generation and filtering of large combinatorial libraries at a remarkable rate of 10,000 molecules per minute. Moreover, the generated products can be filtered to identify subsets of pharmaceutically relevant compounds based on Lipinski's rule of five and blood-brain barrier permeability prediction. We demonstrate the utility of NeuroClick by generating and filtering several thousand molecules for dopamine D3 receptor ligand screening.

Temporal changes of gene expression in health, schizophrenia, bipolar disorder, and major depressive disorder

The molecular events underlying the development, manifestation, and course of schizophrenia, bipolar disorder, and major depressive disorder span from embryonic life to advanced age. However, little is known about the early dynamics of gene expression in these disorders due to their relatively late manifestation. To address this, we conducted a secondary analysis of post-mortem prefrontal cortex datasets using bioinformatics and machine learning techniques to identify differentially expressed gene modules associated with aging and the diseases, determine their time-perturbation points, and assess enrichment with expression quantitative trait loci (eQTL) genes. Our findings revealed early, mid, and late deregulation of expression of functional gene modules involved in neurodevelopment, plasticity, homeostasis, and immune response. This supports the hypothesis that multiple hits throughout life contribute to disease manifestation rather than a single early-life event. Moreover, the time-perturbed functional gene modules were associated with genetic loci affecting gene expression, highlighting the role of genetic factors in gene expression dynamics and the development of disease phenotypes. Our findings emphasize the importance of investigating time-dependent perturbations in gene expression before the age of onset in elucidating the molecular mechanisms of psychiatric disorders.

Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

Phenolic Compounds of Therapeutic Interest in Neuroprotection

The number of elderly people is projected to double in the next 50 years worldwide, resulting in an increased prevalence of neurodegenerative diseases. Aging causes changes in brain tissue homeostasis, thus contributing to the development of neurodegenerative disorders. Current treatments are not entirely effective, so alternative treatments or adjuvant agents are being actively sought. Antioxidant properties of phenolic compounds are of particular interest for neurodegenerative diseases whose psychopathological mechanisms strongly rely on oxidative stress at the brain level. Moreover, phenolic compounds display other advantages such as the permeability of the blood-brain barrier (BBB) and the interesting molecular mechanisms that we reviewed in this work. We began by briefly outlining the physiopathology of neurodegenerative diseases to understand the mechanisms that result in irreversible brain damage, then we provided an overall classification of the phenolic compounds that would be addressed later. We reviewed in vitro and in vivo studies, as well as some clinical trials in which neuroprotective mechanisms were demonstrated in models of different neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), ischemia, and traumatic brain injury (TBI).

Cellular junction dynamics and Alzheimer's disease: a comprehensive review

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by progressive neuronal damage and cognitive decline. Recent studies have shed light on the involvement of not only the blood-brain barrier (BBB) dysfunction but also significant alterations in cellular junctions in AD pathogenesis. In this review article, we explore the role of the BBB and cellular junctions in AD pathology, with a specific focus on the hippocampus. The BBB acts as a crucial protective barrier between the bloodstream and the brain, maintaining brain homeostasis and regulating molecular transport. Preservation of BBB integrity relies on various junctions, including gap junctions formed by connexins, tight junctions composed of proteins such as claudins, occludin, and ZO-1, as well as adherence junctions involving molecules like vascular endothelial (VE) cadherin, Nectins, and Nectin-like molecules (Necls). Abnormalities in these junctions and junctional components contribute to impaired neuronal signaling and increased cerebrovascular permeability, which are closely associated with AD advancement. By elucidating the underlying molecular mechanisms governing BBB and cellular junction dysfunctions within the context of AD, this review offers valuable insights into the pathogenesis of AD and identifies potential therapeutic targets for intervention.

[Mechanobiological Mechanisms Involved in the Regualation of the Blood-Brain Barrier by Fluid Shear Force]

Objective

To explore the mechanobiological mechanism of fluid shear force (FSF) on the protection, injury, and destruction of the structure and function of the blood-brain barrier (BBB) under normal physiological conditions, ischemic hypoperfusion, and postoperative hyperperfusion conditions. BBB is mainly composed of brain microvascular endothelial cells. Rat brain microvascular endothelial cells (rBMECs) were used as model cells to conduct the investigation.

Methods

rBMECs were seeded at a density of 1×105 cells/cm2 and incubated for 48 h. FSF was applied to the rBMECs at 0.5, 2, and 20 dyn/cm2, respectively, simulating the stress BBB incurs under low perfusion, normal physiological conditions, and high FSF after bypass grafting when there is cerebral vascular stenosis. In addition, a rBMECs static culture group was set up as the control (no force was applied). Light microscope, scanning electron microscope (SEM), and laser confocal microscope (LSCM) were used to observe the changes in cell morphology and cytoskeleton. Transmission electron microscope (TEM) was used to observe the tight junctions. Immunofluorescence assay was performed to determine changes in the distribution of tight junction-associated proteins claudin-5, occludin, and ZO-1 and adherens junction-associated proteins VE-cadherin and PECAM-1. Western blot was performed to determine the expression levels of tight junction-associated proteins claudin-5, ZO-1, and JAM4, adherens junction-associated protein VE-cadherin, and key proteins in Rho GTPases signaling (Rac1, Cdc42, and RhoA) under FSF at different intensities.

Results

Microscopic observation showed that the cytoskeleton exhibited disorderly arrangement and irregular orientation under static culture and low shear force (0.5 dyn/cm2). Under normal physiological shear force (2 dyn/cm2), the cytoskeleton was rearranged in the orientation of the FSF and an effective tight junction structure was observed between cells. Under high shear force (20 dyn/cm2), the intercellular space was enlarged and no effective tight junction structure was observed. Immunofluorescence results showed that, under low shear force, the gap between the cells decreased, but there was also decreased distribution of tight junction-associated proteins and adherens junction-associated proteins at the intercellular junctions. Under normal physiological conditions, the cells were tightly connected and most of the tight junction-associated proteins were concentrated at the intercellular junctions. Under high shear force, the gap between the cells increased significantly and the tight junction and adherens junction structures were disrupted. According to the Western blot results, under low shear force, the expression levels of claudin-5, ZO-1, and VE-cadherin were significantly up-regulated compared with those of the control group (P<0.05). Under normal physiological shear force, claudin-5, ZO-1, JAM4, and VE-cadherin were highly expressed compared with those of the control group (P<0.05). Under high shear force, the expressions of claudin-5, ZO-1, JAM4, and VE-cadherin were significantly down-regulated compared with those of the normal physiological shear force group (P<0.05). Under normal physiological shear force, intercellular expressions of Rho GTPases proteins (Rac1, Cdc42, and RhoA) were up-regulated and were higher than those of the other experimental groups (P<0.05). The expressions of Rho GTPases under low and high shear forces were down-regulated compared with that of the normal physiological shear force group (P<0.05).

Conclusion

Under normal physiological conditions, FSF helps maintain the integrity of the BBB structure, while low or high shear force can damage or destroy the BBB structure. The regulation of BBB by FSF is closely related to the expression and distribution of tight junction-associated proteins and adherens junction-associated proteins.

Application of LRG mechanism in normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a prevalent type of hydrocephalus, including secondary normal pressure hydrocephalus (SNPH) and idiopathic normal pressure hydrocephalus (INPH). However, its clinical diagnosis and pathological mechanism are still unclear. Leucine-rich α-2 glycoprotein (LRG) is involved in various human diseases, including cancer, diabetes, cardiovascular disease, and nervous system diseases. Now the physiological mechanism of LRG is still being explored. According to the current research results on LRG, we found that the agency of LRG has much to do with the known pathological process of NPH. This review focuses on analyzing the LRG signaling pathways and the pathological mechanism of NPH. According to the collected literature evidence, we speculated that LRG probably be involved in the pathological process of NPH. Finally, based on the mechanism of LRG and NPH, we also summarized the evidence of molecular targeted therapies for future research and clinical application.

A New Frontier in Phytotherapy: Harnessing the Therapeutic Power of Medicinal Herb-derived miRNAs

Medicinal herbs have been utilized in the treatment of various pathologic conditions, including neoplasms, organ fibrosis, and diabetes mellitus. However, the precise pharmacological actions of plant miRNAs in animals remain to be fully elucidated, particularly in terms of their therapeutic efficacy and mechanism of action. In this review, some important miRNAs from foods and medicinal herbs are presented. Plant miRNAs exhibit a range of pharmacological properties, such as anti-cancer, anti-fibrosis, anti-viral, anti-inflammatory effects, and neuromodulation, among others. These results have not only demonstrated a cross-species regulatory effect, but also suggested that the miRNAs from medicinal herbs are their bioactive components. This shows a promising prospect for plant miRNAs to be used as drugs. Here, the pharmacological properties of plant miRNAs and their underlying mechanisms have been highlighted, which can provide new insights for clarifying the therapeutic mechanisms of medicinal herbs and suggest a new way for developing therapeutic drugs.

Nanoparticle-mediated delivery of non-viral gene editing technology to the brain

Neurological disorders pose a significant burden on individuals and society, affecting millions worldwide. These disorders, including but not limited to Alzheimer's disease, Parkinson's disease, and Huntington's disease, often have limited treatment options and can lead to progressive degeneration and disability. Gene editing technologies, including Zinc Finger Nucleases (ZFN), Transcription Activator-Like Effector Nucleases (TALEN), and Clustered Regularly Interspaced Short Palindromic Repeats-associated Protein 9 (CRISPR-Cas9), offer a promising avenue for potential cures by targeting and correcting the underlying genetic mutations responsible for neurologic disorders. However, efficient delivery methods are crucial for the successful application of gene editing technologies in the context of neurological disorders. The central nervous system presents unique challenges to treatment development due to the blood-brain barrier, which restricts the entry of large molecules. While viral vectors are traditionally used for gene delivery, nonviral delivery methods, such as nanoparticle-mediated delivery, offer safer alternatives that can efficiently transport gene editing components. Herein we aim to introduce the three main gene editing nucleases as nonviral treatments for neurologic disorders, the delivery barriers associated with brain targeting, and the current nonviral techniques used for brain-specific delivery. We highlight the challenges and opportunities for future research in this exciting and growing field that could lead to blood-brain barrier bypassing therapeutic gene editing.

Immunopathology of herpes simplex virus-associated neuroinflammation: Unveiling the mysteries

The immunopathology of herpes simplex virus (HSV)-associated neuroinflammation is a captivating and intricate field of study within the scientific community. HSV, renowned for its latent infection capability, gives rise to a spectrum of neurological expressions, ranging from mild symptoms to severe encephalitis. The enigmatic interplay between the virus and the host's immune responses profoundly shapes the outcome of these infections. This review delves into the multifaceted immune reactions triggered by HSV within neural tissues, intricately encompassing the interplay between innate and adaptive immunity. Furthermore, this analysis delves into the delicate equilibrium between immune defence and the potential for immunopathology-induced neural damage. It meticulously dissects the roles of diverse immune cells, cytokines, and chemokines, unravelling the intricacies of neuroinflammation modulation and its subsequent effects. By exploring HSV's immune manipulation and exploitation mechanisms, this review endeavours to unveil the enigmas surrounding the immunopathology of HSV-associated neuroinflammation. This comprehensive understanding enhances our grasp of viral pathogenesis and holds promise for pioneering therapeutic strategies designed to mitigate the neurological ramifications of HSV infections.

Blood-brain barrier permeability in the ischemic stroke: An update

Stroke is the second leading cause of death globally and the major cause of long-term disability. Among the types of strokes, ischemic stroke, which occurs due to obstruction of blood vessels responsible for cerebral irrigation, is considered the most prevalent, accounting for approximately 86 % of all stroke cases. This interruption of blood supply leads to a critical pathophysiological mechanism, including oxidative stress and neuroinflammation which are responsible for structural alterations of the blood-brain barrier (BBB). The increased BBB permeability associated with cerebral ischemia-reperfusion may contribute to a worse outcome after stroke. Thus, this narrative review aims to update the pathophysiological mechanisms involved in the increase in BBB permeability and to list the possible therapeutic strategies.

Food-Derived Peptides: Beneficial CNS Effects and Cross-BBB Transmission Strategies

Food-derived peptides, as dietary supplements, have significant effects on promoting brain health and relieving central nervous system (CNS) diseases. However, the blood-brain barrier (BBB) greatly limits their in-brain bioavailability. Thus, overcoming the BBB to target the CNS is a major challenge for bioactive peptides in the prevention and treatment of CNS diseases. This review discusses improvement in the neuroprotective function of food-derived active peptides in CNS diseases, as well as the source of BBB penetrating peptides (BBB-shuttles) and the mechanism of transmembrane transport. Notably, this review also discusses various peptide modification methods to overcome the low permeability and stability of the BBB. Lipification, glycosylation, introduction of disulfide bonds, and cyclization are effective strategies for improving the penetration efficiency of peptides through the BBB. This review provides a new prospective for improving their neuroprotective function and developing treatments to delay or even prevent CNS diseases.

The role of microRNAs involved in the disorder of blood-brain barrier in the pathogenesis of multiple sclerosis

miRNAs are involved in various vital processes, including cell growth, development, apoptosis, cellular differentiation, and pathological cellular activities. Circulating miRNAs can be detected in various body fluids including serum, plasma, saliva, and urine. It is worth mentioning that miRNAs remain stable in the circulation in biological fluids and are released from membrane-bound vesicles called exosomes, which protect them from RNase activity. It has been shown that miRNAs regulate blood-brain barrier integrity by targeting both tight junction and adherens junction molecules and can also influence the expression of inflammatory cytokines. Some recent studies have examined the impact of certain commonly used drugs in Multiple Sclerosis on miRNA levels. In this review, we will focus on the recent findings on the role of miRNAs in multiple sclerosis, including their role in the cause of MS and molecular mechanisms of the disease, utilizing miRNAs as diagnostic and clinical biomarkers, using miRNAs as a therapeutic modality or target for Multiple Sclerosis and drug responses in patients, elucidating their importance as prognosticators of disease progression, and highlighting their potential as a future treatment for MS.

Development and validation of PAMPA-BBB QSAR model to predict brain penetration potential of novel drug candidates

Efficiently circumventing the blood-brain barrier (BBB) poses a major hurdle in the development of drugs that target the central nervous system. Although there are several methods to determine BBB permeability of small molecules, the Parallel Artificial Membrane Permeability Assay (PAMPA) is one of the most common assays in drug discovery due to its robust and high-throughput nature. Drug discovery is a long and costly venture, thus, any advances to streamline this process are beneficial. In this study, ∼2,000 compounds from over 60 NCATS projects were screened in the PAMPA-BBB assay to develop a quantitative structure-activity relationship model to predict BBB permeability of small molecules. After analyzing both state-of-the-art and latest machine learning methods, we found that random forest based on RDKit descriptors as additional features provided the best training balanced accuracy (0.70 ± 0.015) and a message-passing variant of graph convolutional neural network that uses RDKit descriptors provided the highest balanced accuracy (0.72) on a prospective validation set. Finally, we correlated in vitro PAMPA-BBB data with in vivo brain permeation data in rodents to observe a categorical correlation of 77%, suggesting that models developed using data from PAMPA-BBB can forecast in vivo brain permeability. Given that majority of prior research has relied on in vitro or in vivo data for assessing BBB permeability, our model, developed using the largest PAMPA-BBB dataset to date, offers an orthogonal means to estimate BBB permeability of small molecules. We deposited a subset of our data into PubChem bioassay database (AID: 1845228) and deployed the best performing model on the NCATS Open Data ADME portal (https://opendata.ncats.nih.gov/adme/). These initiatives were undertaken with the aim of providing valuable resources for the drug discovery community.

Therapeutic strategies for HER2-positive breast cancer with central nervous system involvement: a literature review and future perspectives

Background and Objective

Brain metastases (BMs) are present in approximately 55% of patients with HER2-positive breast cancer (HER2+ BC). The introduction of anti-HER2 agents has radically changed the prognosis of these patients by prolonging overall survival.

Methods

In this review, we describe the biology of central nervous system (CNS) spreading in patients with HER2+ BC. We also provide a literature review of current treatment strategies of brain metastatic BC, focusing on HER2+ disease, and future perspectives.

Key Content and Findings

Treatment of symptomatic BMs includes traditionally neurosurgery and/or radiotherapy, depending on the number of metastases, performance status and systemic disease control. Local treatments, such as surgical excision of BM and stereotactic radiosurgery (SRS), when feasible, are preferred over whole-brain radiotherapy, because of related cognitive impairment. These treatments can lead to a local control of the disease, however, systemic relapses can affect the prognosis of these patients. Recently, new anti-HER2 agents have demonstrated to be effective on BMs, thereby leading to improved survival outcomes with an acceptable quality of life. Despite the clinical benefit of these approaches, BMs still represent a cause of death and effective therapeutic strategies are needed.

Conclusions

Different targeted agents have demonstrated significant efficacy with tolerable safety profiles in HER2+ BC patients with BM, and have already been approved for clinical use in this setting. A better understanding of the molecular mechanisms underlying the onset of BMs could suggest novel targeted approaches in order to prevent CNS localization or delay progression to CNS in HER-2 metastatic patients.

Blood-Brain Barrier Breakdown in Alzheimer's Disease: Mechanisms and Targeted Strategies

The blood-brain barrier (BBB) is a unique and selective feature of the central nervous system's vasculature. BBB dysfunction has been observed as an early sign of Alzheimer's Disease (AD) before the onset of dementia or neurodegeneration. The intricate relationship between the BBB and the pathogenesis of AD, especially in the context of neurovascular coupling and the overlap of pathophysiology in neurodegenerative and cerebrovascular diseases, underscores the urgency to understand the BBB's role more deeply. Preserving or restoring the BBB function emerges as a potentially promising strategy for mitigating the progression and severity of AD. Molecular and genetic changes, such as the isoform ε4 of apolipoprotein E (ApoEε4), a significant genetic risk factor and a promoter of the BBB dysfunction, have been shown to mediate the BBB disruption. Additionally, receptors and transporters like the low-density lipoprotein receptor-related protein 1 (LRP1), P-glycoprotein (P-gp), and the receptor for advanced glycation end products (RAGEs) have been implicated in AD's pathogenesis. In this comprehensive review, we endeavor to shed light on the intricate pathogenic and therapeutic connections between AD and the BBB. We also delve into the latest developments and pioneering strategies targeting the BBB for therapeutic interventions, addressing its potential as a barrier and a carrier. By providing an integrative perspective, we anticipate paving the way for future research and treatments focused on exploiting the BBB's role in AD pathogenesis and therapy.

A Nanostructured Protein Filtration Device for Possible Use in the Treatment of Alzheimer's Disease-Concept and Feasibility after In Vivo Tests

BACKGROUND

Alzheimer's disease (AD), along with other neurodegenerative disorders, remains a challenge for clinicians, mainly because of the incomplete knowledge surrounding its etiology and inefficient therapeutic options. Considering the central role of amyloid beta (Aβ) in the onset and evolution of AD, Aβ-targeted therapies are among the most promising research directions. In the context of decreased Aβ elimination from the central nervous system in the AD patient, the authors propose a novel therapeutic approach based on the "Cerebrospinal Fluid Sink Therapeutic Strategy" presented in previous works. This article aims to demonstrate the laborious process of the development and testing of an effective nanoporous ceramic filter, which is the main component of an experimental device capable of filtrating Aβ from the cerebrospinal fluid in an AD mouse model.

METHODS

First, the authors present the main steps needed to create a functional filtrating nanoporous ceramic filter, which represents the central part of the experimental filtration device. This process included synthesis, functionalization, and quality control of the functionalization, which were performed via various spectroscopy methods and thermal analysis, selectivity measurements, and a biocompatibility assessment. Subsequently, the prototype was implanted in APP/PS1 mice for four weeks, then removed, and the nanoporous ceramic filter was tested for its filtration capacity and potential structural damages.

RESULTS

In applying the multi-step protocol, the authors developed a functional Aβ-selective filtration nanoporous ceramic filter that was used within the prototype. All animal models survived the implantation procedure and had no significant adverse effects during the 4-week trial period. Post-treatment analysis of the nanoporous ceramic filter showed significant protein loading, but no complete clogging of the pores.

CONCLUSIONS

We demonstrated that a nanoporous ceramic filter-based system that filtrates Aβ from the cerebrospinal fluid is a feasible and safe treatment modality in the AD mouse model. The presented prototype has a functional lifespan of around four weeks, highlighting the need to develop advanced nanoporous ceramic filters with anti-biofouling properties to ensure the long-term action of this therapy.

Protein corona on brain targeted nanocarriers: Challenges and prospects

Safe and efficient medical therapy for brain diseases is still an unmet clinical need due to various barriers represented by the blood-brain barrier. Well-designed brain targeted nanocarriers are potential solutions for enhanced brain drug delivery; however, the complicated in vivo process attenuates performance of nanocarriers, which severely hampers clinical translation. The formation of protein corona (PC) is inevitable for nanocarriers circulation and transport in biofluids, acting as an important factor to regulate in vivo performance of nanocarriers. In this review, the reported strategies have been retrospected for better understanding current situation in developing brain targeted nanocarriers. The interplay between brain targeted nanocarriers and plasma proteins is emphasized to comprehend how the nanocarriers adsorb proteins by certain synthetic identity, and following regulations on in vivo performance of nanocarriers. More importantly, the mainstream methods to promote efficiency of nanocarriers by regulating PC, defined as in vitro functionalization and in vivo functionalization strategies, are also discussed. Finally, viewpoints about future development of brain targeted nanocarriers according to the understanding on nanocarriers-PC interaction are proposed.

PRELP secreted from mural cells protects the function of blood brain barrier through regulation of endothelial cell-cell integrity

Introduction: Proline/arginine-rich end leucine-rich repeat protein (PRELP), is a small secreted proteoglycan expressed by pericytes and vascular smooth muscle cells surrounding the brain vasculature of adult mouse. Methods: We utilised a Prelp knockout (Prelp -/-) mouse model to interrogate vasculature integrity in the brain alongside performing in vitro assays to characterise PRELP application to endothelial cells lines. Our findings were supplemented with RNA expression profiling to elucidate the mechanism of how PRELP maintains neurovasculature function. Results: Prelp -/- mice presented with neuroinflammation and reducedneurovasculature integrity, resulting in IgG and dextran leakage in the cerebellum and cortex. Histological analysis of Prelp -/- mice revealed reducedcell-cell integrity of the blood brain barrier, capillary attachment of pericytes andastrocyte end-feet. RNA-sequencing analysis found that cell-cell adhesion andinflammation are affected in Prelp -/- mice and gene ontology analysis as well as gene set enrichment analysis demonstrated that inflammation related processes and adhesion related processes such as epithelial-mesenchymal transition and apical junctions were significantly affected, suggesting PRELP is a regulator of cell-cell adhesion. Immunofluorescence analysis showed that adhesion junction protein expression levels of cadherin, claudin-5, and ZO-1, was suppressed in Prelp -/- mice neurovasculature. Additionally, in vitro studies revealed that PRELP application to endothelial cells enhances cell-cell integrity, induces mesenchymal-endothelial transition and inhibits TGF-β mediated damage to cell-cell adhesion. Discussion: Our study indicates that PRELP is a novel endogenous secreted regulator of neurovasculature integrity and that PRELP application may be a potential treatment for diseases associated with neurovascular damage.