RESUMO
Alzheimer's disease (AD) is the most prevalent form of dementia worldwide and is an emerging global epidemic. Active and passive immune therapies targeting beta amyloid (Aß) have shown very limited evidence in human studies of clinical benefits from these approaches. Epidemiological studies have shown that subjects with type 2 diabetes (T2D) are at higher risk of developing AD. However, whether and how these two conditions are causally linked is unknown. With the purpose of confirming the relationship between T2D and AD, this study specifically focused on effects of insulin in an in vitro model of the human blood-brain barrier (BBB) and on potential mechanisms of action in the treatment of AD. By using a series of assays to establish a BBB model, we demonstrated that insulin treatment alone could induce the increase of brain endothelial barrier properties. The transcriptional response of hCMEC/D3 cells to activation with different concentrations of insulin was determined by RT-PCR, and expression levels of genes involved in the control of barrier permeability, including inter-brain endothelial junctions, integrin-focal adhesions complexes, and transporter system, were found to be altered by the treatment. Notably, the influence of insulin on expression of the ATP-binding cassette (ABC) transporter which contributes to the clearance of Aß was investigated. Insulin up-regulated adherens junction and tight junction transmembrane proteins, as well as the ABC transporter. By treatment with insulin, the models have major advantages: it is fast, it has low cost, it is fit for considerable samples, and its conditions are under control.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Insulina/farmacologia , Transcriptoma/efeitos dos fármacos , Transportadores de Cassetes de Ligação de ATP/genética , Peptídeos beta-Amiloides/metabolismo , Transporte Biológico , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/citologia , Encéfalo/efeitos dos fármacos , Células Cultivadas , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Regulação da Expressão Gênica , Humanos , Hipoglicemiantes/farmacologia , Técnicas In Vitro , Modelos BiológicosRESUMO
We recently established and optimized an immortalized human in vitro blood-brain barrier (BBB) model based on the hBMEC cell line. In the present work, we validated this mono-culture 24-well model with a representative series of drug substances which are known to cross or not to cross the BBB. For each individual compound, a quantitative UHPLC-MS/MS method in Ringer HEPES buffer was developed and validated according to current regulatory guidelines, with respect to selectivity, precision, and reliability. Various biological and analytical challenges were met during method validation, highlighting the importance of careful method development. The positive controls antipyrine, caffeine, diazepam, and propranolol showed mean endothelial permeability coefficients (P e) in the range of 17-70 × 10(-6) cm/s, indicating moderate to high BBB permeability when compared to the barrier integrity marker sodium fluorescein (mean P e 3-5 × 10(-6) cm/s). The negative controls atenolol, cimetidine, and vinblastine showed mean P e values < 10 × 10(-6) cm/s, suggesting low permeability. In silico calculations were in agreement with in vitro data. With the exception of quinidine (P-glycoprotein inhibitor and substrate), BBB permeability of all control compounds was correctly predicted by this new, easy, and fast to set up human in vitro BBB model. Addition of retinoic acid and puromycin did not increase transendothelial electrical resistance (TEER) values of the BBB model.
Assuntos
Barreira Hematoencefálica/metabolismo , Células Endoteliais/metabolismo , Farmacocinética , Encéfalo/irrigação sanguínea , Permeabilidade Capilar , Técnicas de Cultura de Células , Linhagem Celular , Cromatografia Líquida de Alta Pressão , Simulação por Computador , Humanos , Modelos Biológicos , Espectrometria de Massas em TandemRESUMO
The purpose of this study was to clarify the expression of Na(+) -dependent multivitamin transporter (SLC5A6/SMVT) and its contribution to the supply of biotin and pantothenic acid to the human brain via the blood-brain barrier. DNA microarray and immunohistochemical analyses confirmed that SLC5A6 is expressed in microvessels of human brain. The absolute expression levels of SLC5A6 protein in isolated human and monkey brain microvessels were 1.19 and 0.597 fmol/µg protein, respectively, as determined by a quantitative targeted absolute proteomics technique. Using an antibody-free method established by Kubo et al. (2015), we found that SLC5A6 was preferentially localized at the luminal membrane of brain capillary endothelium. Knock-down analysis using SLC5A6 siRNA showed that SLC5A6 accounts for 88.7% and 98.6% of total [(3) H]biotin and [(3) H]pantothenic acid uptakes, respectively, by human cerebral microvascular endothelial cell line hCMEC/D3. SLC5A6-mediated transport in hCMEC/D3 was markedly inhibited not only by biotin and pantothenic acid, but also by prostaglandin E2, lipoic acid, docosahexaenoic acid, indomethacin, ketoprofen, diclofenac, ibuprofen, phenylbutazone, and flurbiprofen. This study is the first to confirm expression of SLC5A6 in human brain microvessels and to provide evidence that SLC5A6 is a major contributor to luminal uptake of biotin and pantothenic acid at the human blood-brain barrier. In humans, it was unclear (not concluded) about what transport system at the blood-brain barrier (BBB) is responsible for the brain uptakes of two vitamins, biotin and pantothenic acid, which are necessary for brain proper function. This study clarified for the first time that the solute carrier 5A6/Na(+) -dependent multivitamin transporter SLC5A6/SMVT is responsible for the supplies of biotin and pantothenic acid into brain across the BBB in humans. DHA, docosahexaenoic acid; NSAID, non-steroidal anti-inflammatory drug; PGE2, prostaglandin E2.
Assuntos
Biotina/metabolismo , Barreira Hematoencefálica/metabolismo , Endotélio Vascular/metabolismo , Ácido Pantotênico/metabolismo , Idoso , Animais , Transporte Biológico Ativo/fisiologia , Barreira Hematoencefálica/citologia , Encéfalo/irrigação sanguínea , Encéfalo/citologia , Encéfalo/metabolismo , Células Cultivadas , Haplorrinos , Humanos , Masculino , Suínos , SimportadoresRESUMO
The blood-brain barrier (BBB) serves as a crucial vascular specialization, shielding and nourishing brain neurons and glia while impeding drug delivery. Here, we conducted single-cell mRNA sequencing of human cerebrovascular cells from 13 surgically resected glioma samples and adjacent normal brain tissue. The transcriptomes of 103,230 cells were mapped, including 57,324 endothelial cells (ECs) and 27,703 mural cells (MCs). Both EC and MC transcriptomes originating from lower-grade glioma were indistinguishable from those of normal brain tissue, whereas transcriptomes from glioblastoma (GBM) displayed a range of abnormalities. Among these, we identified LOXL2-dependent collagen modification as a common GBM-dependent trait and demonstrated that inhibiting LOXL2 enhanced chemotherapy efficacy in both murine and human patient-derived xenograft (PDX) GBM models. Our comprehensive single-cell RNA sequencing-based molecular atlas of the human BBB, coupled with insights into its perturbations in GBM, holds promise for guiding future investigations into brain health, pathology, and therapeutic strategies.
RESUMO
The human blood-brain barrier (hBBB) is a highly specialized structure that regulates passage across blood and central nervous system (CNS) compartments. Despite its critical physiological role, there are no reliable in vitro models that can mimic hBBB development and function. Here, we constructed hBBB assembloids from brain and blood vessel organoids derived from human pluripotent stem cells. We validated the acquisition of blood-brain barrier (BBB)-specific molecular, cellular, transcriptomic, and functional characteristics and uncovered an extensive neuro-vascular crosstalk with a spatial pattern within hBBB assembloids. When we used patient-derived hBBB assembloids to model cerebral cavernous malformations (CCMs), we found that these assembloids recapitulated the cavernoma anatomy and BBB breakdown observed in patients. Upon comparison of phenotypes and transcriptome between patient-derived hBBB assembloids and primary human cavernoma tissues, we uncovered CCM-related molecular and cellular alterations. Taken together, we report hBBB assembloids that mimic the core properties of the hBBB and identify a potentially underlying cause of CCMs.
Assuntos
Barreira Hematoencefálica , Hemangioma Cavernoso do Sistema Nervoso Central , Organoides , Células-Tronco Pluripotentes , Humanos , Organoides/patologia , Organoides/metabolismo , Hemangioma Cavernoso do Sistema Nervoso Central/patologia , Hemangioma Cavernoso do Sistema Nervoso Central/metabolismo , Barreira Hematoencefálica/patologia , Barreira Hematoencefálica/metabolismo , Células-Tronco Pluripotentes/metabolismo , Modelos BiológicosRESUMO
The blood-brain barrier (BBB) is the specialised microvasculature system that shields the central nervous system (CNS) from potentially toxic agents. Attempts to develop therapeutic agents targeting the CNS have been hindered by the lack of predictive models of BBB crossing. In vitro models mimicking the human BBB are of great interest, and advances in induced pluripotent stem cell (iPSC) technologies and the availability of reproducible differentiation protocols have facilitated progress. In this study, we present the efficient differentiation of three different wild-type iPSC lines into brain microvascular endothelial cells (BMECs). Once differentiated, cells displayed several features of BMECs and exhibited significant barrier tightness as measured by trans-endothelial electrical resistance (TEER), ranging from 1500 to >6000 Ωcm2. To assess the functionality of our BBB models, we analysed the crossing efficiency of adeno-associated virus (AAV) vectors and peptide-conjugated antisense oligonucleotides, both currently used in genetic approaches for the treatment of rare diseases. We demonstrated superior barrier crossing by AAV serotype 9 compared to serotype 8, and no crossing by a cell-penetrating peptide-conjugated antisense oligonucleotide. In conclusion, our study shows that iPSC-based models of the human BBB display robust phenotypes and could be used to screen drugs for CNS penetration in culture.
RESUMO
Organ-on-a-chip enables human cell-based 3D tissue culture, which recapitulates the physiological structure and function of the tissue. In terms of the blood-brain barrier (BBB) modeling, the 3D structure of the vessel is essential for studying the cellular interactions among BBB composing cells and investigating the barrier function. Here, we describe a BBB-on-a-chip model with 3D perfusable human vasculature tri-cultured with pericytes and astrocytes. The culture method is based on mimicking angiogenic sprouting since the barrier formation is parallel with angiogenesis during the developmental process. This microfluidic-based 3D tri-culture system enables the comparative study on how surrounding BBB-related cells affect brain angiogenic sprouting. Moreover, the engineered perfusable vasculature is eligible for quantitative analysis on barrier function such as efflux transport system. We expect the BBB-on-a-chip could be used to enhance understanding BBB-related pathologies as well as the drug modulating barrier function of BBB.
Assuntos
Barreira Hematoencefálica , Microfluídica , Encéfalo , Humanos , Dispositivos Lab-On-A-Chip , Neovascularização Patológica/patologia , PericitosRESUMO
There is little information about the functional expression of the multidrug resistance (MDR) transporters P-glycoprotein (P-gp, encoded by ABCB1) and breast cancer resistance protein (BCRP/ABCG2) in the developing blood−brain barrier (BBB). We isolated and cultured primary human fetal brain endothelial cells (hfBECs) from early and mid-gestation brains and assessed P-gp/ABCB1 and BCRP/ABCG2 expression and function, as well as tube formation capability. Immunolocalization of the von Willebrand factor (marker of endothelial cells), zonula occludens-1 and claudin-5 (tight junctions) was detected in early and mid-gestation-derived hfBECs, which also formed capillary-like tube structures, confirming their BEC phenotype. P-gp and BCRP immunostaining was detected in capillary-like tubes and in the cytoplasm and nucleus of hfBECs. P-gp protein levels in the plasma membrane and nuclear protein fractions, as well as P-gp protein/ABCB1 mRNA and BCRP protein levels decreased (p < 0.05) in hfBECs, from early to mid-gestation. No differences in P-gp or BCRP activity in hfBECs were observed between the two age groups. The hfBECs from early and mid-gestation express functionally competent P-gp and BCRP drug transporters and may thus contribute to the BBB protective phenotype in the conceptus from early stages of pregnancy.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Encéfalo/metabolismo , Resistência a Múltiplos Medicamentos , Células Endoteliais/metabolismo , Feminino , Humanos , Proteínas de Neoplasias/metabolismo , GravidezRESUMO
A preclinical blood-brain barrier (BBB) model is important for the study of fundamental transport mechanisms and in accessing the delivery of small molecules and antibodies that target brain. Transwell assays for BBB models are easy to create and use but lack the true 3D anatomy of the brain microvasculature and also often the cell-cell and cell-matrix interactions that are important in ensuring a tight BBB. Here we describe the formation of a BBB that expresses neurovascular membrane transporters, tight junction, and extracellular matrix proteins using the coculture of human-induced pluripotent stem cell-derived endothelial cells (iPSC-EC), brain pericytes (PC), and astrocytes (AC) in a microfluidic device. The BBB model recapitulates human brain vascular permeability with values that are lower than conventional in vitro models and are comparable to in vivo measurements in rat brain. This in vitro BBB model can therefore be used to screen for brain-targeting drugs or to study neurovascular functions.
Assuntos
Reatores Biológicos , Barreira Hematoencefálica/fisiologia , Permeabilidade Capilar , Comunicação Celular , Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/instrumentação , Barreira Hematoencefálica/citologia , Barreira Hematoencefálica/metabolismo , Células Cultivadas , Técnicas de Cocultura , Dextranos/metabolismo , Corantes Fluorescentes/metabolismo , Humanos , Processamento de Imagem Assistida por Computador , Microscopia Confocal , Microscopia de FluorescênciaRESUMO
Polymer nanoparticles (NPs), due to their small size and surface functionalization potential have demonstrated effective drug transport across the blood-brain-barrier (BBB). Currently, the lack of in vitro BBB models that closely recapitulate complex human brain microenvironments contributes to high failure rates of neuropharmaceutical clinical trials. In this work, a previously established microfluidic 3D in vitro human BBB model, formed by the self-assembly of human-induced pluripotent stem cell-derived endothelial cells, primary brain pericytes, and astrocytes in triculture within a 3D fibrin hydrogel is exploited to quantify polymer NP permeability, as a function of size and surface chemistry. Microvasculature are perfused with commercially available 100-400 nm fluorescent polystyrene (PS) NPs, and newly synthesized 100 nm rhodamine-labeled polyurethane (PU) NPs. Confocal images are taken at different timepoints and computationally analyzed to quantify fluorescence intensity inside/outside the microvasculature, to determine NP spatial distribution and permeability in 3D. Results show similar permeability of PS and PU NPs, which increases after surface-functionalization with brain-associated ligand holo-transferrin. Compared to conventional transwell models, the method enables rapid analysis of NP permeability in a physiologically relevant human BBB set-up. Therefore, this work demonstrates a new methodology to preclinically assess NP ability to cross the human BBB.
Assuntos
Barreira Hematoencefálica , Células Endoteliais , Encéfalo , Humanos , Microvasos , PericitosRESUMO
The blood-brain barrier (BBB) regulates molecular trafficking, protects against pathogens, and prevents efficient drug delivery to the brain. Models to date failed to reproduce the human anatomical complexity of brain barriers, contributing to misleading results in clinical trials. To overcome these limitations, a novel 3-dimensional BBB microvascular network model was developed via vasculogenesis to accurately replicate the in vivo neurovascular organization. This microfluidic system includes human induced pluripotent stem cell-derived endothelial cells, brain pericytes, and astrocytes as self-assembled vascular networks in fibrin gel. Gene expression of membrane transporters, tight junction and extracellular matrix proteins, was consistent with computational analysis of geometrical structures and quantitative immunocytochemistry, indicating BBB maturation and microenvironment remodelling. Confocal microscopy validated microvessel-pericyte/astrocyte dynamic contact-interactions. The BBB model exhibited perfusable and selective microvasculature, with permeability lower than conventional in vitro models, and similar to in vivo measurements in rat brain. This robust and physiologically relevant BBB microvascular model offers an innovative and valuable platform for drug discovery to predict neuro-therapeutic transport efficacy in pre-clinical applications as well as recapitulate patient-specific and pathological neurovascular functions in neurodegenerative disease.
Assuntos
Astrócitos/citologia , Barreira Hematoencefálica/citologia , Células Endoteliais/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Pericitos/citologia , Humanos , Dispositivos Lab-On-A-Chip , Microscopia ConfocalRESUMO
BACKGROUND: X-linked adrenoleukodystrophy (X-ALD) is caused by mutations in the ABCD1 gene. 40% of X-ALD patients will convert to the deadly childhood cerebral form (ccALD) characterized by increased permeability of the brain endothelium that constitutes the blood-brain barrier (BBB). Mutation information and molecular markers investigated to date are not predictive of conversion. Prior reports have focused on toxic metabolic byproducts and reactive oxygen species as instigators of cerebral inflammation and subsequent immune cell invasion leading to BBB breakdown. This study focuses on the BBB itself and evaluates differences in brain endothelium integrity using cells from ccALD patients and wild-type (WT) controls. METHODS: The blood-brain barrier of ccALD patients and WT controls was modeled using directed differentiation of induced pluripotent stem cells (iPSCs) into induced brain microvascular endothelial cells (iBMECs). Immunocytochemistry and PCR confirmed characteristic expression of brain microvascular endothelial cell (BMEC) markers. Barrier properties of iBMECs were measured via trans-endothelial electrical resistance (TEER), sodium fluorescein permeability, and frayed junction analysis. Electron microscopy and RNA-seq were used to further characterize disease-specific differences. Oil-Red-O staining was used to quantify differences in lipid accumulation. To evaluate whether treatment with block copolymers of poly(ethylene oxide) and poly(propylene oxide) (PEO-PPO) could mitigate defective properties, ccALD-iBMECs were treated with PEO-PPO block copolymers and their barrier properties and lipid accumulation levels were quantified. RESULTS: iBMECs from patients with ccALD had significantly decreased TEER (2592 ± 110 Ω cm2) compared to WT controls (5001 ± 172 Ω cm2). They also accumulated lipid droplets to a greater extent than WT-iBMECs. Upon treatment with a PEO-PPO diblock copolymer during the differentiation process, an increase in TEER and a reduction in lipid accumulation were observed for the polymer treated ccALD-iBMECs compared to untreated controls. CONCLUSIONS: The finding that BBB integrity is decreased in ccALD and can be rescued with block copolymers opens the door for the discovery of BBB-specific molecular markers that can indicate the onset of ccALD and has therapeutic implications for preventing the conversion to ccALD.
Assuntos
Adrenoleucodistrofia/metabolismo , Barreira Hematoencefálica/metabolismo , Células Endoteliais/metabolismo , Microvasos/metabolismo , Modelos Biológicos , Adrenoleucodistrofia/tratamento farmacológico , Adrenoleucodistrofia/patologia , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Permeabilidade Capilar , Técnicas de Cultura de Células , Diferenciação Celular , Linhagem Celular , Impedância Elétrica , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Gotículas Lipídicas/efeitos dos fármacos , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/patologia , Microvasos/efeitos dos fármacos , Microvasos/patologia , Fármacos Neuroprotetores/farmacologia , Polímeros/farmacologia , TranscriptomaRESUMO
Andrographolide (AG) is a major diterpenoid of the Asian medicinal plant Andrographis paniculata which has shown exciting pharmacological potential for the treatment of inflammation-related pathologies including neurodegenerative disorders. Conversely, the low bioavailability of AG still represents a limiting factor for its use. To overcome these limitations, AG was loaded into human serum albumin based nanoparticles (HSA NPs) and poly ethylcyanoacrylate nanoparticles (PECA NPs). HSA NPs were prepared by thermal (HSAT AG NPs) and chemical cross-linking (HSAC AG NPs), while PECA AG NPs were produced by emulsion-polymerization. NPs were characterized in terms of size, zeta (ζ)-potential, polydispersity, and release studies of AG. In addition, the ability of free AG and AG-loaded in PECA and HSAT NPs to cross the blood-brain barrier (BBB) was assessed using an in vitro BBB model based on human cerebral microvascular endothelial cell line (hCMEC/D3). For BBB drug permeability assays, a quantitative UPLC-MS/MS method for AG in Ringer HEPES buffer was developed and validated according to international regulatory guidelines for industry. Free AG did not permeate the BBB model, as also predicted by in silico studies. HSAT NPs improved by two-fold the permeation of AG while maintaining the integrity of the cell layer, while PECA NPs temporarily disrupted BBB integrity.