Human Blood-brain Barrier Model Research Articles

A Novel Dynamic Human In Vitro Model for Studying the Blood-Brain Barrier.

Constructing areliable in vitro blood-brain barrier (BBB) model using human primary cells has been considered a major challenge during the past decades. These systems could provide valuable information regarding the effect of therapeutic compounds on different BBB cell types (endothelial cells, astrocytes, pericytes) and their ability to cross the barrier in order to reach the brain. Several attempts have been made to develop in vitro BBB models, but these studies mainly used rat, bovine, and porcine cells rather than human primary cells. Genetically modified cell lines have also been used, but they do not appear to maintain physiological properties of the BBB. Here, we describe a detailed protocol for co-culturing and maintaining human brain primary endothelial cells, pericytes, and astrocytes under flow to create an in vitro human BBB model, which can be used for toxicity testing and for studying cross-interaction among different cell types involved in the BBB formation.

In Vitro Models of the Blood-Brain Barrier.

Traditional in vitro models can replicate many essential features of drug transport/permeability across the blood-brain barrier (BBB) but are not entirely projecting in vivo central nervous system (CNS) uptake. Species differences fail to translate experimental therapeutics from the research laboratory to the clinic. Improved in vitro modeling of human BBB is vital for both CNS drug discovery and delivery. High-end human BBB models fabricated by microfluidic technologies offer some solutions to this problem. BBB's complex physiological microenvironment has been established by increasing device complexity in terms of multiple cells, dynamic conditions, and 3D designs. It is now possible to predict the therapeutic effects of a candidate drug and identify new druggable targets by studying multicellular interactions using the advanced in vitro BBB models. This chapter reviews the current as well as an ideal in vitro model of the BBB.

Highly cationic cell-penetrating peptides affect the barrier integrity and facilitates mannitol permeation in a human stem cell-based blood-brain barrier model

The blood-brain barrier (BBB) allows passive permeation of only a limited number of, primarily lipophilic, low-molecular weight drugs that obey the so-called “rule of CNS likeness”. Therefore, novel strategies to facilitate drug delivery across the BBB are needed. Cell-penetrating peptides (CPPs) enable delivery of various therapeutic cargoes into cells and may potentially serve as shuttles for delivery of brain-specific drugs across the BBB. The CPPs Tat47–57 and penetratin are prototypical cationic CPPs, whereas apidaecin and oncocin belong to the group of proline-rich cationic antimicrobial peptides displaying CPP-like properties.The aim of the present study was to investigate the potential of Tat47–57, penetratin, apidaecin, and oncocin for interaction with and permeation of the BBB in vitro. We also studied whether the CPPs facilitated permeation of the paracellular flux marker mannitol as well as the transcellular flux marker propranolol. The peptides were labelled with the fluorophore 6-TAMRA (T) for visualization and quantification purposes. CPP membrane-adherence, membrane-embedding, and cellular uptake as well as barrier-permeation were evaluated in murine brain capillary endothelial cells (bEND3) and human induced pluripotent stem cell-derived (Bioni-010c) brain capillary endothelial-like monolayers. The cationic and the proline-rich cationic CPPs were taken up into the Bioni-010c monolayers. T-Tat47–57, T-apidaecin, and T-oncocin also permeated Bioni-010c monolayers, whereas T-penetratin did not. However, both T-Tat47–57 and T-penetratin affected the barrier integrity to a degree that facilitated permeation of 14C-mannitol. These results may therefore pave the way for future CPP-mediated brain delivery of small drugs that do not obey the “rule of CNS likeness”.

New BBB Model Reveals That IL-6 Blockade Suppressed the BBB Disorder, Preventing Onset of NMOSD.

Background and ObjectivesTo evaluate the pathophysiology of neuromyelitis optica spectrum disorder (NMOSD) and the therapeutic mechanism and levels of interleukin-6 (IL-6) blockade (satralizumab), especially with respect to blood-brain barrier (BBB) disruption with the new in vitro and ex vivo human BBB models and in vivo model.MethodsWe constructed new static in vitro and flow-based ex vivo models for evaluating continued barrier function, leukocyte transmigration, and intracerebral transferability of neuromyelitis optica-immunoglobulin G (NMO-IgG) and satralizumab across the BBB using the newly established triple coculture system that are specialized to closely mimic endothelial cell contact of pericytes and endfeet of astrocytes. In the in vivo study, we assessed the effects of an anti–IL-6 receptor antibody for mice (MR16-1) on in vivo BBB disruption in mice with experimental autoimmune encephalomyelitis in which IL-6 concentration in the spinal cord dramatically increases.ResultsIn vitro and ex vivo experiments demonstrated that NMO-IgG increased intracerebral transferability of satralizumab and NMO-IgG and that satralizumab suppressed the NMO-IgG–induced transmigration of T cells and barrier dysfunction. In the in vivo study, the blockade of IL-6 signaling suppressed the migration of T cells into the spinal cord and prevented the increased BBB permeability.DiscussionThese results suggest that (1) our triple-cultured in vitro and in ex vivo BBB models are ideal for evaluating barrier function, leukocyte transmigration, and intracerebral transferability; (2) NMO-IgG increased the intracerebral transferability of NMO-IgG via decreasing barrier function and induced secretion of IL-6 from astrocytes causing more dysfunction of the barrier and disrupting controlled cellular infiltration; and (3) satralizumab, which can pass through the BBB in the presence of NMO-IgG, suppresses the BBB dysfunction and the infiltration of inflammatory cells, leading to prevention of onset of NMOSD.

A Hybrid Nanofiber/Paper Cell Culture Platform for Building a 3D Blood-brain Barrier Model.

The blood brain barrier (BBB) protects the central nervous system from toxins and pathogens in the blood by regulating permeation of molecules through the barrier interface. In vitro BBB models described to date reproduce some aspects of BBB functionality, but also suffer from incomplete phenotypic expression of brain endothelial traits, difficulty in reproducibility and fabrication, or overall cost. To address these limitations, we describe a three-dimensional (3D) BBB model based on a hybrid paper/nanofiber scaffold. The cell culture platform utilizes lens paper as a framework to accommodate 3D culture of astrocytes. An electrospun nanofiber layer is coated onto one face of the paper to mimic the basement membrane and support growth of an organized two-dimensional layer of endothelial cells (ECs). Human induced pluripotent stem cell-derived ECs and astrocytes are co-cultured to develop a human BBB model. Morphological and spatial organization of model are validated with confocal microscopy. Measurements of transendothelial resistance and permeability demonstrate the BBB model develops a high-quality barrier and responds to hyperosmolar treatments. RNA-sequencing shows introduction of astrocytes both regulates EC tight junction proteins and improves endothelial phenotypes related to vasculogenesis. This model shows promise as a model platform for future in vitro studies of the BBB.

Engineered models for studying blood-brain-barrier-associated brain physiology and pathology

The blood-brain barrier (BBB) is a transport barrier that suppresses the translocation of potentially harmful substances to the brain tissue. Although the BBB is known to be associated with many kinds of neuropathology, such as neuroinflammation and neurodegenerative diseases, the conventionally used animal and Transwell models cannot provide sufficient information due to genetic and functional heterogeneity in comparison with humans and limited monitoring capabilities. Recently, human cell-based three-dimensional BBB models have been developed, and these models provide in vivo-like BBB structures and functions. In this review, we provide an overview of the recent advances in BBB models with a particular focus on the simulation of BBB-associated brain physiology and neuropathology. To this end, important factors for recapitulating the in vivo characteristics of the BBB are described. Furthermore, approaches to recapitulate the BBB physiology using engineering methods are summarized. The applications of BBB models in the study of neuropathology, such as inflammation and neurodegenerative diseases, are also presented.

Successful Prediction of Human Steady-State Unbound Brain-to-Plasma Concentration Ratio of P-gp Substrates Using the Proteomics-Informed Relative Expression Factor Approach.

In order to optimize central nervous system (CNS) drug development, accurate prediction of the drug’s human steady‐state unbound brain interstitial fluid‐to‐plasma concentration ratio (Kp,uu,brain) is critical, especially for drugs that are effluxed by the multiple drug resistance transporters (e.g., P‐glycoprotein, P‐gp). Due to lack of good in vitro human blood‐brain barrier models, we and others have advocated the use of a proteomics‐informed relative expressive factor (REF) approach to predict Kp,uu,brain. Therefore, we tested the success of this approach in humans, with a focus on P‐gp substrates, using brain positron emission tomography imaging data for verification. To do so, the efflux ratio (ER) of verapamil, N‐desmethyl loperamide, and metoclopramide was determined in human P‐gp‐transfected MDCKII cells using the Transwell assay. Then, using the ER estimate, Kp,uu,brain of the drug was predicted using REF (ER approach). Alternatively, in vitro passive and P‐gp–mediated intrinsic clearances (CLs) of these drugs, estimated using a five‐compartmental model, were extrapolated to in vivo using REF (active CL) and brain microvascular endothelial cells protein content (passive CL). The ER approach successfully predicted Kp,uu,brain of all three drugs within twofold of observed data and within 95% confidence interval of the observed data for verapamil and N‐desmethyl loperamide. Using the in vitro–to–in vivo extrapolated clearance approach, Kp,uu,brain was reasonably well predicted but not the brain unbound interstitial fluid drug concentration‐time profile. Therefore, we propose that the ER approach be used to predict Kp,uu,brain of CNS candidate drugs to enhance their success in development.

Development, Characterization and Potential Applications of a Multicellular Spheroidal Human Blood–Brain Barrier Model Integrating Three Conditionally Immortalized Cell Lines

In vitro blood-brain barrier (BBB) models are essential research tools for use in developing brain-targeted drugs and understanding the physiological and pathophysiological functions of the BBB. To develop BBB models with better functionalities, three-dimensional (3D) culture methods have gained significant attention as a promising approach. In this study, we report on the development of a human conditionally immortalized cell-based multicellular spheroidal BBB (hiMCS-BBB) model. After being seeded into non-attachment culture wells, HASTR/ci35 (astrocytes) and HBPC/ci37 cells (brain pericytes) self-assemble to form a spheroid core that is then covered with an outer monolayer of HBMEC/ci18 cells (brain microvascular endothelial cells). The results of immunocytochemistry showed the protein expression of several cellular junction and BBB-enriched transporter genes in HBMEC/ci18 cells of the spheroid model. The permeability assays showed that the hiMCS-BBB model exhibited barrier functions against the penetration of dextran (5 kDa and 70 kDa) and rhodamine123 (a P-glycoprotein substrate) into the core. On the other hand, facilitation of 2-NBDG (a fluorescent glucose analog) uptake was observed in the hiMCS-BBB model. Furthermore, tumor necrosis factor-alpha treatment elicited an inflammatory response in HBMEC/ci18 cells, thereby suggesting that BBB inflammation can be recapitulated in the hiMCS-BBB model. To summarize, we have developed an hiMCS-BBB model that possesses fundamental BBB properties, which can be expected to provide a useful and highly accessible experimental platform for accelerating various BBB studies.

Central Nervous System (CNS) Viral Seeding by Mature Monocytes and Potential Therapies To Reduce CNS Viral Reservoirs in the cART Era.

The human immunodeficiency virus (HIV) enters the central nervous system (CNS) within a few days after primary infection, establishing viral reservoirs that persist even with combined antiretroviral therapy (cART). We show that monocytes from people living with HIV (PLWH) on suppressive cART harboring integrated HIV, viral mRNA, and/or viral proteins preferentially transmigrate across the blood-brain barrier (BBB) to CCL2 and are significantly enriched post-transmigration, and even more highly enriched posttransmigration than T cells with similar properties. Using HIV-infected ART-treated mature monocytes cultured in vitro, we recapitulate these findings and demonstrate that HIV+ CD14+ CD16+ ART-treated monocytes also preferentially transmigrate. Cenicriviroc and anti-JAM-A and anti-ALCAM antibodies significantly and preferentially reduce/block transmigration of HIV+ CD14+ CD16+ ART-treated monocytes. These findings highlight the importance of monocytes in CNS HIV reservoirs and suggest targets to eliminate their formation and reseeding.IMPORTANCE We characterized mechanisms of CNS viral reservoir establishment/replenishment using peripheral blood mononuclear cells (PBMC) of PLWH on cART and propose therapeutic targets to reduce/block selective entry of cells harboring HIV (HIV+) into the CNS. Using DNA/RNAscope, we show that CD14+ CD16+ monocytes with integrated HIV, transcriptionally active, and/or with active viral replication from PBMC of PLWH prescribed cART and virally suppressed, selectively transmigrate across a human BBB model. This is the first study to our knowledge demonstrating that monocytes from PLWH with HIV disease for approximately 22 years and with long-term documented suppression can still carry virus into the CNS that has potential to be reactivated and infectious. This selective entry into the CNS-and likely other tissues-indicates a mechanism of reservoir formation/reseeding in the cART era. Using blocking studies, we propose CCR2, JAM-A, and ALCAM as targets on HIV+ CD14+ CD16+ monocytes to reduce and/or prevent CNS reservoir replenishment and to treat HAND and other HIV-associated comorbidities.

Evaluation of a human iPSC-derived BBB model for repeated dose toxicity testing with cyclosporine A as model compound

The blood-brain barrier (BBB) is a highly restrictive barrier that preserves central nervous system homeostasis and ensures optimal brain functioning. Using BBB cell assays makes it possible to investigate whether a compound is likely to compromise BBBs functionality, thereby probably resulting in neurotoxicity. Recently, several protocols to obtain human brain-like endothelial cells (BLECs) from induced pluripotent stem cells (iPSCs) have been reported. Within the framework of the European MSCA-ITN in3 project, we explored the possibility to use an iPSC-derived BBB model to assess the effects of repeated dose treatment with chemicals, using Cyclosporine A (CsA) as a model compound. The BLECs were found to exhibit important BBB characteristics up to 15 days after the end of the differentiation and could be used to assess the effects of repeated dose treatment. Although BLECs were still undergoing transcriptional changes over time, a targeted transcriptome analysis (TempO-Seq) indicated a time and concentration dependent activation of ATF4, XBP1, Nrf2 and p53 stress response pathways under CsA treatment. Taken together, these results demonstrate that this iPSC-derived BBB model and iPSC-derived models in general hold great potential to study the effects of repeated dose exposure with chemicals, allowing personalized and patient-specific studies in the future.

Flow induces barrier and glycocalyx-related genes and negative surface charge in a lab-on-a-chip human blood-brain barrier model

Microfluidic lab-on-a-chip (LOC) devices allow the study of blood-brain barrier (BBB) properties in dynamic conditions. We studied a BBB model, consisting of human endothelial cells derived from hematopoietic stem cells in co-culture with brain pericytes, in an LOC device to study fluid flow in the regulation of endothelial, BBB and glycocalyx-related genes and surface charge. The highly negatively charged endothelial surface glycocalyx functions as mechano-sensor detecting shear forces generated by blood flow on the luminal side of brain endothelial cells and contributes to the physical barrier of the BBB. Despite the importance of glycocalyx in the regulation of BBB permeability in physiological conditions and in diseases, the underlying mechanisms remained unclear. The MACE-seq gene expression profiling analysis showed differentially expressed endothelial, BBB and glycocalyx core protein genes after fluid flow, as well as enriched pathways for the extracellular matrix molecules. We observed increased barrier properties, a higher intensity glycocalyx staining and a more negative surface charge of human brain-like endothelial cells (BLECs) in dynamic conditions. Our work is the first study to provide data on BBB properties and glycocalyx of BLECs in an LOC device under dynamic conditions and confirms the importance of fluid flow for BBB culture models.

Time-Dependent Internalization of Polymer-Coated Silica Nanoparticles in Brain Endothelial Cells and Morphological and Functional Effects on the Blood-Brain Barrier.

Nanoparticle (NP)-assisted procedures including laser tissue soldering (LTS) offer advantages compared to conventional microsuturing, especially in the brain. In this study, effects of polymer-coated silica NPs used in LTS were investigated in human brain endothelial cells (ECs) and blood-brain barrier models. In the co-culture setting with ECs and pericytes, only the cell type directly exposed to NPs displayed a time-dependent internalization. No transfer of NPs between the two cell types was observed. Cell viability was decreased relatively to NP exposure duration and concentration. Protein expression of the nuclear factor ĸ-light-chain-enhancer of activated B cells and various endothelial adhesion molecules indicated no initiation of inflammation or activation of ECs after NP exposure. Differentiation of CD34+ ECs into brain-like ECs co-cultured with pericytes, blood-brain barrier (BBB) characteristics were obtained. The established endothelial layer reduced the passage of integrity tracer molecules. NP exposure did not result in alterations of junctional proteins, BBB formation or its integrity. In a 3-dimensional setup with an endothelial tube formation and tight junctions, barrier formation was not disrupted by the NPs and NPs do not seem to cross the blood-brain barrier. Our findings suggest that these polymer-coated silica NPs do not damage the BBB.

Multifunctional Liposomes Modulate Purinergic Receptor-Induced Calcium Wave in Cerebral Microvascular Endothelial Cells and Astrocytes: New Insights for Alzheimer\u2019s disease

In light of previous results, we assessed whether liposomes functionalized with ApoE-derived peptide (mApoE) and phosphatidic acid (PA) (mApoE-PA-LIP) impacted on intracellular calcium (Ca2+) dynamics in cultured human cerebral microvascular endothelial cells (hCMEC/D3), as an in vitro human blood-brain barrier (BBB) model, and in cultured astrocytes. mApoE-PA-LIP pre-treatment actively increased both the duration and the area under the curve (A.U.C) of the ATP-evoked Ca2+ waves in cultured hCMEC/D3 cells as well as in cultured astrocytes. mApoE-PA-LIP increased the ATP-evoked intracellular Ca2+ waves even under 0 [Ca2+]e conditions, thus indicating that the increased intracellular Ca2+ response to ATP is mainly due to endogenous Ca2+ release. Indeed, when Sarco-Endoplasmic Reticulum Calcium ATPase (SERCA) activity was blocked by cyclopiazonic acid (CPA), the extracellular application of ATP failed to trigger any intracellular Ca2+ waves, indicating that metabotropic purinergic receptors (P2Y) are mainly involved in the mApoE-PA-LIP-induced increase of the Ca2+ wave triggered by ATP. In conclusion, mApoE-PA-LIP modulate intracellular Ca2+ dynamics evoked by ATP when SERCA is active through inositol-1,4,5-trisphosphate-dependent (InsP3) endoplasmic reticulum Ca2+ release. Considering that P2Y receptors represent important pharmacological targets to treat cognitive dysfunctions, and that P2Y receptors have neuroprotective effects in neuroinflammatory processes, the enhancement of purinergic signaling provided by mApoE-PA-LIP could counteract Aβ-induced vasoconstriction and reduction in cerebral blood flow (CBF). Our obtained results could give an additional support to promote mApoE-PA-LIP as effective therapeutic tool for Alzheimer’s disease (AD).

Glycans to improve efficacy and solubility of protein aggregation inhibitors.

Glycans to improve efficacy and solubility of protein aggregation inhibitors.

Isolation of Primary Human and Rodent Brain Microvascular Endothelial Cells: Culturing, Characterization, and High-Efficiency Transfection.

Studies of blood-brain barrier (BBB) require developing of a novel andconvenient in vitro endothelial cell model. We isolated primary human and rodent brain microvascular endothelial cells and developed methods for culturing, characterization, and high-efficiency transfection of endothelial cells. Here, we describe the improved methods to obtain in vitro human and rodent BBB models to study expression of endogenous and exogenous genes of interest.

In Vitro Human Blood-Brain Barrier Model for Drug Permeability Testing.

Blood-brain barrier (BBB), although very important for protection of brain from major neurotoxins, negatively affects the treatment of central nervous system diseases by limiting the passage of neuropharmaceuticals from blood to the brain. Thus, researchers have to investigate the passage of the produced drug molecules through the BBB before they are introduced to the market. Although these experiments have been traditionally performed on experimental animals, drug permeability tests are now carried out mostly by in vitro BBB models due to ethical problems, differences between species, and expensive and troublesome in vivo test procedures. In this method, we explain how to model and characterize a realistic in vitro BBB model using human derived cells and perform a drug permeability test using this model.

Circulating microRNAs Associated With Reversible Cerebral Vasoconstriction Syndrome.

The purpose of this study was to investigate the significance of circulating micro RNAs (miRNAs) in the pathogenesis of reversible cerebral vasoconstriction syndrome (RCVS). We prospectively recruited 3 independent cohorts of patients with RCVS and age-matched and sex-matched controls in a single medical center. Next-generation small RNA sequencing followed by quantitative polymerase chain reaction (PCR) was used to identify and validate differentially expressed miRNAs, which was cross-validated in migraine patients in ictal stage or interictal stage. Computational analysis was used to predict the target genes of miRNAs, followed by in vitro functional analysis. We identified a panel of miRNAs including miR-130a-3p, miR-130b-3p, let-7a-5p, let-7b-5p, and let-7f-5p that well differentiated patients with RCVS from controls (area under the receiver operating characteristics curve [AUC] was 0.906, 0.890, and 0.867 in the 3 cohorts, respectively). The abundance of let-7a-5p, let-7b-5p, and let-7f-5p, but not miR-130a-3p nor miR-130b-3p, was significantly higher in patients with ictal migraine compared with that of controls and patients with interictal migraine. Target prediction and pathway enrichment analysis suggested that the transforming growth factor-β signaling pathway and endothelin-1 responsible for vasomotor control might link these miRNAs to RCVS pathogenesis, which was confirmed in vitro by transfecting miRNAs mimics or incubating the patients' cerebrospinal fluid (CSF) in 3 different vascular endothelial cells. Moreover, miR-130a-3p was associated with imaging-proven disruption of the blood-brain barrier (BBB) in patients with RCVS and its overexpression led to reduced transendothelial electrical resistance (ie, increased permeability) in in vitro human BBB model. We identified the circulating miRNA signatures associated with RCVS, which may be functionally linked to its headache, BBB integrity, and vasomotor function. ANN NEUROL 2021;89:459-473.

Intermittent Hypoxia and Its Impact on Nrf2/HIF-1α Expression and ABC Transporters: An in Vitro Human Blood-Brain Barrier Model Study.

Obstructive sleep apnea (OSA) is characterized by repeated episodes of complete or partial obstruction of the upper airways, leading to chronic intermittent hypoxia (IH). OSA patients are considered at high cerebrovascular risk and may also present cognitive impairment. One hypothesis explored is that disturbances may be linked to blood-brain barrier (BBB) dysfunction. The BBB is a protective barrier separating the brain from blood flow. The BBB limits the paracellular pathway through tight and adherens junctions, and the transcellular passage by efflux pumps (ABC transporters). The aims of this study were to evaluate the impact of IH and sustained hypoxia (SH) on a validated in vitro BBB model and to investigate the factors expressed under both conditions. Exposure of endothelial cells (HBEC-5i) in our in vitro model of BBB to hypoxia was performed using IH cycles: 1% O2-35 min/18% O2-25 min for 6 cycles or 6 h of SH at 1% O2. After exposure, we studied the cytotoxicity and the level of ROS in our cells. We measured the apparent BBB permeability using sodium fluorescein, FITC-dextran and TEER measurement. Whole cell ELISA were performed to evaluate the expression of tight junctions, ABC transporters, HIF-1α and Nrf2. The functionality of ABC transporters was evaluated with accumulation studies. Immunofluorescence assays were also conducted to illustrate the whole cell ELISAs. Our study showed that 6 h of IH or SH induced a BBB disruption marked by a significant decrease in junction protein expressions (claudin-5, VE-cadherin, ZO-1) and an increase in permeability. We also observed an upregulation in P-gp protein expression and functionality and a downregulation in BCRP. Hypoxia induced production of ROS, Nrf2 and HIF-1α. They were expressed in both sustained and intermittent conditions, but the expression and the activity of P-gp and BCRP were different. Understanding these mechanisms seems essential in order to propose new therapeutic strategies for patients with OSA.

Naphthoquinone-Dopamine Hybrids Inhibit α-Synuclein Aggregation, Disrupt Preformed Fibrils, and Attenuate Aggregate-Induced Toxicity.

Accumulation and aggregation of the intrinsically disordered protein α-synuclein (α-Syn) into amyloid fibrils are hallmarks of a series of heterogeneous neurodegenerative disorders, known as synucleinopathies and most notably Parkinson's disease (PD). The crucial role of α-Syn aggregation in PD makes it an attractive target for the development of disease-modifying therapeutics that would inhibit α-Syn aggregation or disrupt its preformed fibrillar assemblies. To this end, we have designed and synthesized two naphthoquinone-dopamine-based hybrid small molecules, NQDA and Cl-NQDA, and demonstrated their ability to inhibit in vitro amyloid formation by α-Syn using ThT assay, CD, TEM, and Congo red birefringence. Moreover, these hybrid molecules efficiently disassembled preformed fibrils of α-Syn into nontoxic species, as evident from LUV leakage assay. NQDA and Cl-NQDA were found to have low cytotoxicity and they attenuated the toxicity induced by α-Syn towards SH-SY5Y neuroblastoma cells. NQDA was found to efficiently cross an in vitro human blood-brain barrier model. These naphthoquinone-dopamine based derivatives can be an attractive scaffold for therapeutic design towards PD.

Lactose-appended β-cyclodextrin as an effective nanocarrier for brain delivery

The blood-brain barrier (BBB) prevents the permeability of drugs into the brain, and as such limits the management of various brain diseases. To overcome this barrier, drug-encapsulating nanoparticles or vesicles, drug conjugates, and other types of drug delivery systems (DDSs) have been developed. However, the brain-targeting ability of nanoparticles or vesicles is still insufficient. Recently, among the various brain-targeting ligands previously studied for facilitating transcellular BBB transport, several sugar-appended nanocarriers for brain delivery were identified. Meanwhile, cyclodextrins (CyDs) have been used as nanocarriers for drug delivery since they can encapsulate hydrophobic compounds with high biocompatibility. Therefore, in this study, we created various sugar-appended β-cyclodextrins (β-CyDs) to discover novel brain-targeting ligands. As a result, of the six sugar-appended CyDs, lactose-appended β-CyD (Lac-β-CyD) showed greater cellular uptake in hCMEC/D3 cells, human brain microvascular endothelial cells, than other sugar-appended β-CyDs did. In addition, the permeability of Lac-β-CyD within the in vitro human BBB model was greater than that of other sugar-appended β-CyDs. Moreover, Lac-β-CyD significantly accumulated in the mouse brain after intravenous administration. Thus, Lac-β-CyD efficiently facilitated the accumulation of the model drug into the mouse brain. These findings suggest that Lac-β-CyD has the potential to be a novel carrier for drugs across the BBB.