Cerebrospinal Fluid Barrier Research Articles

Choroid plexus extracellular vesicle transport of blood-borne insulin-like growth factor 1 to the hippocampus of the immature brain

Abstract Reduced serum level of insulin-like growth factor 1 (IGF-1), a major regulator of perinatal development, in extremely preterm infants has been shown to be associated with neurodevelopmental impairment. To clarify the mechanism of IGF-1 transport at the blood-cerebrospinal fluid (CSF) barrier of the immature brain, we combined studies of in vivo preterm piglet and rabbit models with an in vitro transwell cell culture model of neonatal primary murine choroid plexus epithelial (ChPE) cells. We identified IGF-1 positive intracellular vesicles in ChPE cells and provided data indicating a directional transport of IGF-1 from the basolateral to the apical media in extracellular vesicles (EVs). Exposure of the ChPE cells to human IGF-1 on the basolateral side increased the secretion of IGF-1 positive EVs in the apical media. Mass spectrometry analysis displayed similarities in protein content between EVs derived from preterm piglet CSF and ChPE derived EVs. Furthermore, exposure of ChPE cells to human IGF-1 caused an enrichment of human IGF-1 and transmembrane p24 trafficking protein 2, proteins important for perinatal development, in apical media derived EVs. Moreover, intraventricular injections of ChPE cell-derived EVs in preterm rabbit pups resulted in an uptake of EVs in the brain, displaying penetration through the ependymal lining and deep into the hippocampus. Finally, exposure of rat hippocampus neurons to ChPE cell derived EVs resulted in internalization of the EVs in hippocampal soma and neurites. In summary, we describe a transport pathway for blood-borne IGF-1 in EVs, through the blood–CSF barrier to the hippocampus in the immature brain.

Free Kappa light chain in a sample of Egyptian multiple sclerosis patients (a pilot study)

BackgroundMultiple sclerosis is a chronic autoimmune-mediated demyelinating disease of the central nervous system that is usually associated with varying degrees of progressive disability. Free Kappa light chain (FKLC) has attracted growing attention as a significant diagnostic marker of MS. Our aim was to study the diagnostic utility of cerebrospinal fluid free Kappa light chain and related indices in a sample of Egyptian MS patients vs. CSF IgG oligoclonal bands. It was a prospective case–control study of MS patients carried in our hospital during the period from January 2021 till January 2022. Our study carried on 30 patients with multiple sclerosis and other inflammatory neurologic diseases and 20 age and sex matched controls. The study measured FKLC in the CSF and serum sample pairs of patients and control group. Indices calculated using FKLC measured in CSF and serum included; FKLC index, FKLC intrathecal fraction and quotient of FKLC. Indices were used to assess intrathecal synthesis of FKLC considering blood–CSF barrier function. Receiver operating characteristic curve analysis was used to determine diagnostic performance of FKLC and related indices in comparison to CSF–OCB testing.ResultsMeasured FKLC levels as well as its calculated indices have shown statistically significant higher values among MS patients against OIND patients and healthy control group. Both FKLC index and FKLC IF were similarly showing 100% diagnostic sensitivity and 100% diagnostic specificity for MS diagnosis.ConclusionsFKLC biomarkers are proposed to be highly sensitive and easy to detect first-line markers of intrathecal immunoglobulin synthesis with accurate performance and low cost that might prove to be promising diagnostic markers of MS.

Comparative study on the immune surveillance injury of blood cerebrospinal fluid barrier induced by exposure to lead acetate and nano-lead sulfide

Objective: To investigate the differences in terms of blood cerebrospinal fluid barrier immune surveillance injury by lead acetate and nano-lead sulfide exposure in order to provide basis for the study of their mechanism of nerve injury caused by exposure to lead and nano lead. Methods: In June 2015, forty-five SPF SD male rats were randomly divided into control group, lead acetate group (20 mg/kg) and nano-lead sulfide group (20 mg/kg), with 15 rats in each group. The rats were intragastric five times a week, for nine weeks. The numbers of CD4(+) T lymphocytes in blood and cerebrospinal fluid were detected by flow cytometry. The levels of interleukin-4 (IL-4) and interferon-γ (IFN-γ) in serum and cerebrospinal fluid were detected by ELISA. The expressions and distribution of intercellular cell adhesion molecule-1 (ICAM-1) and CD4(+) T lymphocytes in choroid plexus were detected by laser confocal fluorescence immunoassay. The mRNA expression levels of IL-4, IFN-γ and ICAM-1 in the choroid plexus were detected by real-time PCR. Results: Compared with the control group, the proportion of CD4(+) T lymphocytes in blood of rats in lead acetate group was increased, the proportions of CD4(+) T lymphocytes in cerebrospinal fluid of rats in lead acetate group and nano-lead sulfide group were increased, the contents of IL-4 and IFN-γ in serum of rats in lead acetate group and nano-lead sulfide group were increased, the content of IL-4 in cerebrospinal fluid of rats in lead acetate group and the contents of IL-4 and IFN-γ in cerebrospinal fluid of rats in nano-lead sulfide group were increased, the differences were statistically significant (P<0.05). The fluorescence intensity of ICAM-1 and CD4(+) T lymphocytes in choriochoroid plexus of rats in lead acetate group and nano-lead sulfide group were stronger than those in control group, and the fluorescence intensity of CD4(+) T lymphocytes of rats in nano-lead sulfide group was weaker than that in lead acetate group. Compared with the control group, the mRNA expression levels of ICAM-1, IL-4 and IFN-γ in choriochoroids plexus of rats in lead acetate group and nano-lead sulfide group were increased, and the mRNA expression levels of ICAM-1 and IL-4 in nano-lead sulfide group were higher than those in lead acetate group, while the mRNA expression level of IFN-γ in nano-lead sulfide group was lower than that in lead acetate group (P<0.05) . Conclusion: Exposure to lead and nano-lead sulfide can cause the increase of CD4(+) T lymphocytes, IL-4, IFN-γ and ICAM-1, which may be related to the damage to the immune surveillance of the blood cerebrospinal fluid barrier. And there is a difference in the injury caused by lead and nano-lead sulfide exposure.

Highly restrictive and directional penetration of the blood cerebral spinal fluid barrier by JCPyV.

The human polyomavirus JCPyV is an opportunistic pathogen that infects greater than 60% of the world's population. The virus establishes a persistent and asymptomatic infection in the urogenital system but can cause a fatal demyelinating disease in immunosuppressed or immunomodulated patients following invasion of the CNS. The mechanisms responsible for JCPyV invasion into CNS tissues are not known but direct invasion from the blood to the cerebral spinal fluid via the choroid plexus has been hypothesized. To study the potential of the choroid plexus as a site of neuroinvasion, we used an adult human choroid plexus epithelial cell line to model the blood-cerebrospinal fluid (B-CSF) barrier in a transwell system. We found that these cells formed a highly restrictive barrier to virus penetration either as free virus or as virus associated with extracellular vesicles (EVJC+). The restriction was not absolute and small amounts of virus or EVJC+ penetrated and were able to establish foci of infection in primary astrocytes. Disruption of the barrier with capsaicin did not increase virus or EVJC+ penetration leading us to hypothesize that virus and EVJC+ were highly cell-associated and crossed the barrier by an active process. An inhibitor of macropinocytosis increased virus penetration from the basolateral (blood side) to the apical side (CSF side). In contrast, inhibitors of clathrin and raft dependent transcytosis reduced virus transport from the basolateral to the apical side of the barrier. None of the drugs inhibited apical to basolateral transport suggesting directionality. Pretreatment with cyclosporin A, an inhibitor of P-gp, MRP2 and BCRP multidrug resistance transporters, restored viral penetration in cells treated with raft and clathrin dependent transcytosis inhibitors. Because choroid plexus epithelial cells are known to be susceptible to JCPyV infection both in vitro and in vivo we also examined the release of infectious virus from the barrier. We found that virus was preferentially released from the cells into the apical (CSF) chamber. These data show clearly that there are two mechanisms of penetration, direct transcytosis which is capable of seeding the CSF with small amounts of virus, and infection followed by directional release of infectious virions into the CSF compartment.

The recent research progress in neurobiological characteristics and pain regulation of the cerebrospinal fluid-contacting nucleus

AbstractThe ependymal epithelium forms the cerebrospinal fluid barrier, separating the brain and spinal cord from the cerebrospinal fluid. However, in specific regions of the central nervous system, there are neurons that directly interface with the cerebrospinal fluid, including neuronal bodies, dendrites, or axons, This constitutes what is referred to as the "cerebrospinal fluid contacting neurons system (CSF-CNS)". The research team led by Professor Zhang has successfully utilized cholera toxin subunit B coupled horseradish peroxidase complex (CB-HRP) to selectively label the specialized neuron system that interfaces with cerebrospinal fluid, pioneeringly designating it as the "cerebrospinal fluid-contacting nucleus", commonly referred to as the "CSF-contacting nucleus". For the first time, the discovery of the CSF-contacting nucleus provides compelling morphological evidence for the existence of a distinct neural structure within the brain parenchyma that establishes a connection with the cerebrospinal fluid, thereby suggesting its potential significance in facilitating material and information exchange between the brain parenchyma and cerebrospinal fluid. After conducting a comprehensive series of studies on the morphological structure, material expression, gene analysis and functional aspects of the CSF-contacting nucleus in rodents and non-human primates, it has been revealed that there are fibrous connections between the CSF-contacting nucleus and the cerebral cortex and subcortical nuclei being involved in the regulatory mechanisms of pain, cognition, learning and memory, emotion, addiction, stress and anxiety responses, visceral activity, olfaction, vision processing and perception, auditory processing, perception, motor control and coordination, homeostasis regulation including maintenance of body energy and fluid balance, as well as the control of sleep–wake cycles and synchronization of biological rhythms. Current experiments have confirmed that the CSF-contacting nucleus is related to pain, morphine dependence and withdrawal, learning and memory, as well as stress. This present article offers a comprehensive review of the neurobiological characteristics and recent advancements in pain regulation of the CSF-contacting nucleus. The aim is to provide novel insights into the investigation of pain regulation within bidirectional regulatory pathway between the brain and cerebrospinal fluid, with a specific focus on elucidating the role of the CSF-contacting nucleus as a bridge structure. Additionally, the objective of this research is to propose innovative strategies for pain management and associated disorders in the future.

CNS Viral Infections-What to Consider for Improving Drug Treatment: A Plea for Using Mathematical Modeling Approaches.

Neurotropic viruses may cause meningitis, myelitis, encephalitis, or meningoencephalitis. These inflammatory conditions of the central nervous system (CNS) may have serious and devastating consequences if not treated adequately. In this review, we first summarize how neurotropic viruses can enter the CNS by (1) crossing the blood-brain barrier or blood-cerebrospinal fluid barrier; (2) invading the nose via the olfactory route; or (3) invading the peripheral nervous system. Neurotropic viruses may then enter the intracellular space of brain cells via endocytosis and/or membrane fusion. Antiviral drugs are currently used for different viral CNS infections, even though their use and dosing regimens within the CNS, with the exception of acyclovir, are minimally supported by clinical evidence. We therefore provide considerations to optimize drug treatment(s) for these neurotropic viruses. Antiviral drugs should cross the blood-brain barrier/blood cerebrospinal fluid barrier and pass the brain cellular membrane to inhibit these viruses inside the brain cells. Some antiviral drugs may also require intracellular conversion into their active metabolite(s). This illustrates the need to better understand these mechanisms because these processes dictate drug exposure within the CNS that ultimately determine the success of antiviral drugs for CNS infections. Finally, we discuss mathematical model-based approaches for optimizing antiviral treatments. Thereby emphasizing the potential of CNS physiologically based pharmacokinetic models because direct measurement of brain intracellular exposure in living humans faces ethical restrictions. Existing physiologically based pharmacokinetic models combined with in vitro pharmacokinetic/pharmacodynamic information can be used to predict drug exposure and evaluate efficacy of antiviral drugs within the CNS, to ultimately optimize the treatments of CNS viral infections.

Bacterial and host factors involved in zoonotic Streptococcal meningitis

Zoonotic streptococci cause several invasive diseases with high mortality rates, especially meningitis. Numerous studies elucidated the meningitis pathogenesis of zoonotic streptococci, some specific to certain bacterial species. In contrast, others are shared among different bacterial species, involving colonization and invasion of mucosal barriers, survival in the bloodstream, breaching the blood–brain and/or blood–cerebrospinal fluid barrier to access the central nervous system, and triggering inflammation of the meninges. This review focuses on the recent advancements in comprehending the molecular and cellular events of five major zoonotic streptococci responsible for causing meningitis in humans or animals, including Streptococcus agalactiae, Streptococcus equi subspecies zooepidemicus, Streptococcus suis, Streptococcus dysgalactiae, and Streptococcus iniae. The underlying mechanism was summarized into four themes, including 1) bacterial survival in blood, 2) brain microvascular endothelial cell adhesion and invasion, 3) penetration of the blood–brain barrier, and 4) activation of the immune system and inflammatory reaction within the brain. This review may contribute to developing therapeutics to prevent or mitigate injury of streptococcal meningitis and improve risk stratification.

Magnetic resonance imaging with upconversion nanoprobes capable of crossing the blood-cerebrospinal fluid barrier

The central nervous system (CNS) maintains homeostasis with its surrounding environment by restricting the ingress of large hydrophilic molecules, immune cells, pathogens, and other external harmful substances to the brain. This function relies heavily on the blood-cerebrospinal fluid (B-CSF) and blood-brain barrier (BBB). Although considerable research has examined the structure and function of the BBB, the B-CSF barrier has received little attention. Therapies for disorders associated with the central nervous system have the potential to benefit from targeting the B-CSF barrier to enhance medication penetration into the brain. In this study, we synthesized a nanoprobe ANG-PEG-UCNP capable of crossing the B-CSF barrier with high targeting specificity using a hydrocephalus model for noninvasive magnetic resonance ventriculography to understand the mechanism by which the CSF barrier may be crossed and identify therapeutic targets of CNS diseases. This magnetic resonance nanoprobe ANG-PEG-UCNP holds promising potential as a safe and effective means for accurately defining the ventricular anatomy and correctly locating sites of CSF obstruction.

Enhancing of cerebral Abeta clearance by modulation of ABC transporter expression: a review of experimental approaches.

Clearance of amyloid-beta (Aβ) from the brain is impaired in both early-onset and late-onset Alzheimer's disease (AD). Mechanisms for clearing cerebral Aβ include proteolytic degradation, antibody-mediated clearance, blood brain barrier and blood cerebrospinal fluid barrier efflux, glymphatic drainage, and perivascular drainage. ATP-binding cassette (ABC) transporters are membrane efflux pumps driven by ATP hydrolysis. Their functions include maintenance of brain homeostasis by removing toxic peptides and compounds, and transport of bioactive molecules including cholesterol. Some ABC transporters contribute to lowering of cerebral Aβ. Mechanisms suggested for ABC transporter-mediated lowering of brain Aβ, in addition to exporting of Aβ across the blood brain and blood cerebrospinal fluid barriers, include apolipoprotein E lipidation, microglial activation, decreased amyloidogenic processing of amyloid precursor protein, and restricting the entrance of Aβ into the brain. The ABC transporter superfamily in humans includes 49 proteins, eight of which have been suggested to reduce cerebral Aβ levels. This review discusses experimental approaches for increasing the expression of these ABC transporters, clinical applications of these approaches, changes in the expression and/or activity of these transporters in AD and transgenic mouse models of AD, and findings in the few clinical trials which have examined the effects of these approaches in patients with AD or mild cognitive impairment. The possibility that therapeutic upregulation of ABC transporters which promote clearance of cerebral Aβ may slow the clinical progression of AD merits further consideration.

Cerebrospinal fluid findings in patients with neurological manifestations in post-COVID-19 syndrome

BackgroundInformation on cerebrospinal fluid (CSF) findings in patients with neurological manifestations in post-COVID-19 syndrome is scarce.MethodsRetrospective evaluation of 84 CSF samples in patients fulfilling post-COVID-19 criteria in two neurological post-COVID-19 outpatient clinics.ResultsIn 68% of samples, all CSF parameters were normal. The most frequent pathological CSF finding was elevation of total protein (median total protein 33.3 mg/dl [total range 18.5–116.2]) in 20 of 83 (24%) samples. The second most prevalent pathological finding was a blood–CSF barrier dysfunction as measured by elevation of QAlb (median QAlb 4.65 [2.4–13.2]) in 11/84 (13%). Pleocytosis was found in only 5/84 (6%) samples and was mild in all of them. CSF-restricted oligoclonal bands were found in 5/83 (6%) samples. Anti-neuronal autoantibodies in CSF were negative in most cases, whilst 12/68 (18%) samples were positive for anti-myelin autoantibodies in serum. PCR for herpesviridae (HSV-1/-2, VZV, EBV, CMV, HHV6) showed, if at all, only weakly positive results in CSF or EDTA whole blood/plasma.ConclusionsThe majority of samples did not show any pathologies. The most frequent findings were elevation of total protein and blood–CSF barrier dysfunction with no signs of intrathecal inflammation. CSF analysis still keeps its value for exclusion of differential diagnoses.

Expression of Collagen VI, Anticollagenase, Laminin, MM9, Claudins 1 and 5, N and E Cadherins in Choroid Plexus Tumors

Background: CPTs are rare intraventricular papillary neoplasms derived from the choroid plexus epithelium. Anti-collagenase and extracellular matrix which have not been expressed in brain tumors. Objective: The purpose of this study was to investigate the expression levels of collagen type VI, anti-collagenase, laminin, MM9, claudins 1 and 5, N and E cadherins, and collagen VII, tejido, and collagen degradation enzyme complexes in choroid plexus tumors. Materials and methods: We studied the expression of adhesion molecules, extracellular matrix, and anticollagenase with an immunohistochemistry approach and electron microscopy analysis in 42 choroid plexus tumors. Results: 28(67%) were choroid plexus papillomas, 8 (19%) were atypical choroid plexus papillomas and 6 (14%) were choroid plexus carcinomas. The Ki67-li and MVD increased from CPC to ACPP, being the highest in malignant tumors as well as a strong immunoexpression of anti-collagenase and were inverse correlation with claudin 5, E, and N cadherin and collagen IV immunoexpressions which added further significant information to the prognosis and varied according to the histologic classification. By ultrastructure, the loss of basal membrane and cilia, disorganization, and proliferation of ECM were observed in CPC. Cerebral homeostasis largely results from the ability of both the Blood–Brain Barrier (BBB) at the brain microvascular endothelium and the Blood–Cerebrospinal Fluid Barrier (BCSFB) at the epithelium of the Choroid Plexuses (CPs), to control the composition of the CSF and cerebral extracellular fluid. Under expression of the tight junction proteins occludin, claudin-1 and claudin-5 are key molecular abnormalities responsible for the increased permeability of tumor endothelial tight junctions. Conclusion: The loss of basement membrane and ECM overexpression could be considered as a poor prognosis predictor in CPT. Anti-collagenase and MMP9 overexpression could be related to basal membrane and BBB plasticity in CPTs.

Enhancing Antibody Exposure in the Central Nervous System: Mechanisms of Uptake, Clearance, and Strategies for Improved Brain Delivery

Antibodies (mAbs) are attractive molecules for their application as a diagnostic and therapeutic agent for diseases of the central nervous system (CNS). mAbs can be generated to have high affinity and specificity to target molecules in the CNS. Unfortunately, only a very small number of mAbs have been specifically developed and approved for neurological indications. This is primarily attributed to their low exposure within the CNS, hindering their ability to reach and effectively engage their potential targets in the brain. This review discusses aspects of various barriers such as the blood–brain barrier (BBB) and blood–cerebrospinal fluid (CSF) barrier (BCSFB) that regulate the entry and clearance of mAbs into and from the brain. The roles of the glymphatic system on brain exposure and clearance are being described. We also discuss the proposed mechanisms of the uptake of mAbs into the brain and for clearance. Finally, several methods of enhancing the exposure of mAbs in the CNS were discussed, including receptor-mediated transcytosis, osmotic BBB opening, focused ultrasound (FUS), BBB-modulating peptides, and enhancement of mAb brain retention.

ICAM2 initiates trans-blood-CSF barrier migration and stemness properties in leptomeningeal metastasis of triple-negative breast cancer

Leptomeningeal metastasis (LM) occurs when tumor cells spread to the leptomeningeal space surrounding the brain and the spinal cord, thereby causing poor clinical outcomes. The triple-negative breast cancer (TNBC) has been associated with symptoms of LM and mechanism remained unclear. Through proteomic analysis, we identified high expression of ICAM2 in leptomeningeal metastatic TNBC cells, which promoted the colonization of the spinal cord and resulted in poor survival in vivo. Two-way demonstration indicated that high levels of ICAM2 promoted blood–cerebrospinal fluid barrier (BCB) adhesion, trans-BCB migration, and stemness abilities and determined the specificity of LM in vivo. Furthermore, pull-down and antibody neutralizing assay revealed that ICAM2 determined the specificity of LM through interactions with ICAM1 in the choroid plexus epithelial cells. Therefore, neutralizing ICAM2 can attenuate the progression of LM and prolong survival in vivo. The results suggested that targeting ICAM2 is a potential therapeutic strategy for LM in TNBC.

Increased CCL-5 (RANTES) Gene Expression in the Choroid Plexus of Dogs with Canine Leishmaniosis

Visceral canine leishmaniasis (CanL) can cause several clinical manifestations, including neurological lesions. Few reports have characterized the lesions observed in the central nervous system (CNS) during CanL; however, its pathogenesis remains unclear. The choroid plexus (CP) is a specialized structure responsible for the production and secretion of cerebrospinal fluid (CSF) and considered an interface between the peripheral immune system and CNS. It can allow the passage of inflammatory cells or pathogens and has the potential to act as a source of inflammatory mediators in several diseases. Thus, this study aimed to evaluate the role of CP as a possible route of inflammatory cells in the development of brain lesions in dogs with CanL, as well as its association with blood–CSF barrier (BCSFB) dysfunction. Samples were collected from 19 dogs that were naturally infected with CanL. We evaluated the histopathological lesions in the brain and investigated the gene expression of the cytokines. Capture enzyme-linked immunosorbent assay (ELISA) was used to evaluate the presence of the same cytokines in the CSF. Biochemical analysis was performed to compare the presence of albumin in the serum and CSF. Indirect ELISA was performed to measure the presence of anti-Leishmania antibodies in the CSF, which would suggest the disruption of the BCSFB. Histopathological evaluation of the dogs’ brains revealed mild-to-severe inflammatory infiltrates, mainly in the CP and meninges. We also detected the presence of anti-Leishmania antibodies and albumin in the CSF, as well as Leishmania DNA in the CP. The gene expression of CCL-5 was increased in the CP of infected dogs compared with that of controls, and there was a tendency for the increase in the gene expression of CXCL-10. Thus, our findings confirm the disfunction of the BCSFB during CanL and suggest that the chemokines CCL-5 and CXCL-10 can be responsible for the recruitment of inflammatory cells found in CP.

Focused Ultrasound-Mediated Blood–Brain Barrier Opening Best Promotes Neuroimmunomodulation through Brain Macrophage Redistribution

Neuroimmunomodulation is a promising form of drug-free treatment for neurological diseases ranging from Alzheimer’s disease to depression. The evidence supporting the efficacy of focused ultrasound (FUS) neuroimmunomodulation is encouraging; however, the method has yet to be standardized, and its mechanism remains poorly understood. Methods of FUS neuroimmunomodulation can be categorized into three paradigms based on the parameters used. In the first paradigm, focused ultrasound blood–brain barrier opening (FUS-BBBO) combines FUS with microbubbles (MB) to transiently and safely induce BBB opening. In the second paradigm, focused ultrasound neuromodulation (FUS-N) harnesses the acoustic effects of FUS alone (without MB). In the third paradigm, focused ultrasound with microbubbles without BBBO (FUS + MB) combines MB with FUS below the BBBO pressure threshold—harnessing the mechanical effects of FUS without opening the barrier. Due to the recent evidence of brain macrophage modulation in response to FUS-BBBO, we provide the first direct comparison of brain macrophage modulation between all three paradigms both in the presence and absence of Alzheimer’s disease (AD) pathology. Flow cytometry and single-cell sequencing are employed to identify FUS-BBBO as the FUS paradigm, which maximizes brain macrophage modulation, including an increase in the population of neuroprotective, disease-associated microglia and direct correlation between treatment cavitation dose and brain macrophage phagocytosis. Next, we combine spatial and single-cell transcriptomics with immunohistochemical validation to provide the first characterization of brain macrophage distribution in response to FUS-BBBO. Given their relevance within neurodegeneration and perturbation response, we emphasize the analysis of three brain macrophage populations—disease- and interferon-associated microglia and central-nervous-system-associated macrophages. We find and validate the redistribution of each population with an overall trend toward increased interaction with the brain–cerebrospinal fluid barrier (BCSFB) after FUS-BBBO, an effect that is found to be more pronounced in the presence of disease pathology. This study addresses the prior lack of FUS neuroimmunomodulation paradigm optimization and mechanism characterization, identifying that FUS-BBBO best modulates brain macrophage response via complex redistribution.

Cerebrospinal Fluid-Basic Concepts Review.

Cerebrospinal fluid plays a crucial role in protecting the central nervous system (CNS) by providing mechanical support, acting as a shock absorber, and transporting nutrients and waste products. It is produced in the ventricles of the brain and circulates through the brain and spinal cord in a continuous flow. In the current review, we presented basic concepts related to cerebrospinal fluid history, cerebrospinal fluid production, circulation, and its main components, the role of the blood-brain barrier and the blood-cerebrospinal fluid barrier in the maintenance of cerebrospinal fluid homeostasis, and the utility of Albumin Quotient (QAlb) evaluation in the diagnosis of CNS diseases. We also discussed the collection of cerebrospinal fluid (type, number of tubes, and volume), time of transport to the laboratory, and storage conditions. Finally, we briefly presented the role of cerebrospinal fluid examination in CNS disease diagnosis of various etiologies and highlighted that research on identifying cerebrospinal fluid biomarkers indicating disease presence or severity, evaluating treatment effectiveness, and enabling understanding of pathogenesis and disease mechanisms is of great importance. Thus, in our opinion, research on cerebrospinal fluid is still necessary for both the improvement of CNS disease management and the discovery of new treatment options.

Polymeric nanocarriers for nose-to-brain drug delivery in neurodegenerative diseases and neurodevelopmental disorders.

Neurodegenerative diseases are progressive conditions that affect the neurons of the central nervous system (CNS) and result in their damage and death. Neurodevelopmental disorders include intellectual disability, autism spectrum disorder, and attention-deficit/hyperactivity disorder and stem from the disruption of essential neurodevelopmental processes. The treatment of neurodegenerative and neurodevelopmental conditions, together affecting ∼120 million people worldwide, is challenged by the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier that prevent the crossing of drugs from the systemic circulation into the CNS. The nose-to-brain pathway that bypasses the BBB and increases the brain bioavailability of intranasally administered drugs is promising to improve the treatment of CNS conditions. This pathway is more efficient for nanoparticles than for solutions, hence, the research on intranasal nano-drug delivery systems has grown exponentially over the last decade. Polymeric nanoparticles have become key players in the field owing to the high design and synthetic flexibility. This review describes the challenges faced for the treatment of neurodegenerative and neurodevelopmental conditions, the molecular and cellular features of the nasal mucosa and the contribution of intranasal nano-drug delivery to overcome them. Then, a comprehensive overview of polymeric nanocarriers investigated to increase drug bioavailability in the brain is introduced.

Inflammatory Response and Exosome Biogenesis of Choroid Plexus Organoids Derived from Human Pluripotent Stem Cells.

The choroid plexus (ChP) is a complex structure in the human brain that is responsible for the secretion of cerebrospinal fluid (CSF) and forming the blood-CSF barrier (B-CSF-B). Human-induced pluripotent stem cells (hiPSCs) have shown promising results in the formation of brain organoids in vitro; however, very few studies to date have generated ChP organoids. In particular, no study has assessed the inflammatory response and the extracellular vesicle (EV) biogenesis of hiPSC-derived ChP organoids. In this study, the impacts of Wnt signaling on the inflammatory response and EV biogenesis of ChP organoids derived from hiPSCs was investigated. During days 10-15, bone morphogenetic protein 4 was added along with (+/-) CHIR99021 (CHIR, a small molecule GSK-3β inhibitor that acts as a Wnt agonist). At day 30, the ChP organoids were characterized by immunocytochemistry and flow cytometry for TTR (~72%) and CLIC6 (~20%) expression. Compared to the -CHIR group, the +CHIR group showed an upregulation of 6 out of 10 tested ChP genes, including CLIC6 (2-fold), PLEC (4-fold), PLTP (2-4-fold), DCN (~7-fold), DLK1 (2-4-fold), and AQP1 (1.4-fold), and a downregulation of TTR (0.1-fold), IGFBP7 (0.8-fold), MSX1 (0.4-fold), and LUM (0.2-0.4-fold). When exposed to amyloid beta 42 oligomers, the +CHIR group had a more sensitive response as evidenced by the upregulation of inflammation-related genes such as TNFα, IL-6, and MMP2/9 when compared to the -CHIR group. Developmentally, the EV biogenesis markers of ChP organoids showed an increase over time from day 19 to day 38. This study is significant in that it provides a model of the human B-CSF-B and ChP tissue for the purpose of drug screening and designing drug delivery systems to treat neurological disorders such as Alzheimer's disease and ischemic stroke.

Leptomeningeal Disease (LMD) in Patients with Melanoma Metastases.

Leptomeningeal disease (LMD) is a devastating complication caused by seeding malignant cells to the cerebrospinal fluid (CSF) and the leptomeningeal membrane. LMD is diagnosed in 5-15% of patients with systemic malignancy. Management of LMD is challenging due to the biological and metabolic tumor microenvironment of LMD being largely unknown. Patients with LMD can present with a wide variety of signs and/or symptoms that could be multifocal and include headache, nausea, vomiting, diplopia, and weakness, among others. The median survival time for patients with LMD is measured in weeks and up to 3-6 months with aggressive management, and death usually occurs due to progressive neurologic dysfunction. In melanoma, LMD is associated with a suppressive immune microenvironment characterized by a high number of apoptotic and exhausted CD4+ T-cells, myeloid-derived suppressor cells, and a low number of CD8+ T-cells. Proteomics analysis revealed enrichment of complement cascade, which may disrupt the blood-CSF barrier. Clinical management of melanoma LMD consists primarily of radiation therapy, BRAF/MEK inhibitors as targeted therapy, and immunotherapy with anti-PD-1, anti-CTLA-4, and anti-LAG-3 immune checkpoint inhibitors. This review summarizes the biology and anatomic features of melanoma LMD, as well as the current therapeutic approaches.

NLRP3-dependent lipid droplet formation contributes to posthemorrhagic hydrocephalus by increasing the permeability of the blood–cerebrospinal fluid barrier in the choroid plexus

Hydrocephalus is a severe complication that can result from intracerebral hemorrhage, especially if this hemorrhage extends into the ventricles. Our previous study indicated that the NLRP3 inflammasome mediates cerebrospinal fluid hypersecretion in the choroid plexus epithelium. However, the pathogenesis of posthemorrhagic hydrocephalus remains unclear, and therapeutic strategies for prevention and treatment are lacking. In this study, an Nlrp3−/− rat model of intracerebral hemorrhage with ventricular extension and primary choroid plexus epithelial cell culture were used to investigate the potential effects of NLRP3-dependent lipid droplet formation and its role in the pathogenesis of posthemorrhagic hydrocephalus. The data indicated that NLRP3-mediated dysfunction of the blood–cerebrospinal fluid barrier (B-CSFB) accelerated neurological deficits and hydrocephalus, at least in part, through the formation of lipid droplets in the choroid plexus; these lipid droplets interacted with mitochondria and increased the release of mitochondrial reactive oxygen species that destroyed tight junctions in the choroid plexus after intracerebral hemorrhage with ventricular extension. This study broadens the current understanding of the relationship among NLRP3, lipid droplets and the B-CSFB and provides a new therapeutic target for the treatment of posthemorrhagic hydrocephalus. Strategies to protect the B-CSFB may be effective therapeutic approaches for posthemorrhagic hydrocephalus.