• Beta-amyloid
• Blood-brain barrier
• LRP1
• Mitochondria
• RAGE
• Redox status

• Russian Science Foundation

• Alzheimer’s disease
• cell-cell signaling
• neural integrity
• neurodegeneration
• neuroinflammation

• Fundação para a Ciência e a Tecnologia

• 3D models
• blood-brain barrier
• human
• in vitro model
• transwell

• aging
• angiogenesis
• blood-brain barrier
• cerebral blood flow
• cerebrovascular abnormalities
• neurodegeneration
• neurodevelopment and intellectual disabilities

• blood–brain barrier
• cell-to-cell communication
• exosomes
• extracellular vesicles
• neuroinflammation

Synergistic impairment of the blood-brain barrier (BBB) induced by methamphetamine (METH) and HIV-Tat protein increases the risk of HIV-associated neurocognitive disorders (HAND) in HIV-positive METH abusers. Studies have shown that oxidative stress plays a vital role in METH- and HIV-Tat-induced damage to the BBB but have not clarified the mechanism. This study uses the human brain microvascular endothelial cell line hCMEC/D3 and tree shrews to investigate whether the transient receptor potential melastatin 2 (TRPM2) channel, a cellular effector of the oxidative stress, might regulate synergistic damage to the BBB caused by METH and HIV-Tat. We showed that METH and HIV-Tat damaged the BBB in vitro, producing abnormal cell morphology, increased apoptosis, reduced protein expression of the tight junctions (TJ) including Junctional adhesion molecule A (JAMA) and Occludin, and a junctional associated protein Zonula occludens 1 (ZO1), and increased the flux of sodium fluorescein (NaF) across the hCMEC/D3 cells monolayer. METH and HIV-Tat co-induced the oxidative stress response, reducing catalase (CAT), glutathione peroxidase (GSH-PX), and superoxide dismutase (SOD) activity, as well as increased reactive oxygen species (ROS) and malonaldehyde (MDA) level. Pretreatment with n-acetylcysteine amide (NACA) alleviated the oxidative stress response and BBB damage characterized by improving cell morphology, viability, apoptosis levels, TJ protein expression levels, and NaF flux. METH and HIV-Tat co-induced the activation and high protein expression of the TRPM2 channel, however, early intervention using 8-Bromoadenosine-5′-O-diphosphoribose (8-Br-ADPR), an inhibitor of TPRM2 channel, or TRPM2 gene knockdown attenuated the BBB damage. Oxidative stress inhibition reduced the activation and high protein expression of the TRPM2 channel in the in vitro model, which in turn reduced the oxidative stress response. Further, 8-Br-ADPR attenuated the effects of METH and HIV-Tat on the BBB in tree shrews—namely, down-regulated TJ protein expression and increased BBB permeability to Evans blue (EB) and NaF. In summary, the TRPM2 channel can regulate METH- and HIV-Tat-induced oxidative stress and BBB injury, giving the channel potential for developing drug interventions to reduce BBB injury and neuropsychiatric symptoms in HIV-infected METH abusers.

• HIV-tat protein
• blood-brain barrier
• methamphetamine
• oxidative stress
• transient receptor potential melastatin 2 channel

In vascular dementia (VaD) and Alzheimer’s disease (AD), cerebral hypoperfusion and blood‐brain barrier (BBB) leakiness contribute to brain damage. In this study, we have measured biochemical markers and mediators of cerebral hypoperfusion and BBB in the frontal (BA6) and parietal (BA7) cortex and underlying white matter, to investigate the pathophysiology of vascular dysfunction in AD, VaD and mixed dementia. The ratio of myelin‐associated glycoprotein to proteolipid protein‐1 (MAG:PLP1), a post‐mortem biochemical indicator of the adequacy of ante‐mortem cerebral perfusion; the concentration of fibrinogen adjusted for haemoglobin level, a marker of blood‐brain barrier (BBB) leakiness; the level of vascular endothelial growth factor‐A (VEGF), a marker of tissue hypoxia; and endothelin‐1 (EDN1), a potent vasoconstrictor, were measured by ELISA in the frontal and parietal cortex and underlying white matter in 94 AD, 20 VaD, 33 mixed dementia cases and 58 age‐matched controls. All cases were assessed neuropathologically for small vessel disease (SVD), cerebral amyloid angiopathy (CAA) severity, Aβ and phospho‐tau parenchymal load, and Braak tangle stage. Aβ40 and Aβ42 were measured by ELISA in guanidine‐HCl tissue extracts. We found biochemical evidence of cerebral hypoperfusion in AD, VaD and mixed dementia to be associated with SVD, Aβ level, plaque load, EDN1 level and Braak tangle stage, and to be most widespread in mixed dementia. There was evidence of BBB leakiness in AD—limited to the cerebral cortex and related to EDN1 level. In conclusion, abnormalities of cerebral perfusion and BBB function in common types of dementia can largely be explained by a combination of arteriolosclerosis, and Aβ‐, tau‐ and endothelin‐related vascular dysfunction. The relative contributions of these processes vary considerably both between and within the diseases.

• Alzheimer’s disease
• blood-brain barrier
• cerebral hypoperfusion
• mixed dementia
• pathophysiology
• vascular dementia

• BBB
• GLUTs
• HIV-Tat protein
• TJs
• gastrodin
• methamphetamine

• Angiotensin receptor blockers
• Angiotensin-converting enzyme inhibitors
• Angiotensin-converting enzyme-2
• COVID-19
• Cognitive impairment
• Dementia
• SARS-CoV-2
• Stroke
• White matter ischaemia

• Brain Diseases/epidemiology
• Brain Diseases/virology
• COVID-19/complications
• Cognition Disorders/epidemiology
• Cognition Disorders/virology
• Humans
• SARS-CoV-2

• MC_PC_13088 Medical Research Council
• Alzheimer's Society (UK)
• Alzheimer's Research UK
• BrightFocus Foundation

The function and regulation of amyloid-beta (Aβ) in healthy and diseased liver remains unexplored. Because Aβ reduces the integrity of the blood-brain barrier we have examined its potential role in regulating the sinusoidal permeability of normal and cirrhotic liver. Aβ and key proteins that generate (beta-secretase 1 and presenilin-1) and degrade it (neprilysin and myelin basic protein) were decreased in human cirrhotic liver. In culture, activated hepatic stellate cells (HSC) internalized Aβ more efficiently than astrocytes and HSC degraded Aβ leading to suppressed expression of α-smooth muscle actin (α-SMA), collagen 1 and transforming growth factor β (TGFβ). Aβ also upregulated sinusoidal permeability marker endothelial NO synthase (eNOS) and decreased TGFβ in cultured human liver sinusoidal endothelial cells (hLSEC). Liver Aβ levels also correlate with the expression of eNOS in transgenic Alzheimer’s disease mice and in human and rodent cirrhosis/fibrosis. These findings suggest a previously unexplored role of Aβ in the maintenance of liver sinusoidal permeability and in protection against cirrhosis/fibrosis via attenuation of HSC activation.

• Alzheimer’s disease
• astrocytes
• beta secretase
• endothelial nitric oxide synthase
• hepatic stellate cells
• liver cirrhosis
• liver sinusoidal endothelial cells
• liver sinusoidal permeability
• myelin basic protein
• neprilysin
• presenilin

• Amyloid beta-Peptides/pharmacology
• Amyloid beta-Peptides/therapeutic use
• Animals
• Disease Models, Animal
• Fibrosis/drug therapy
• Gene Expression/genetics
• Humans
• Liver Cirrhosis/physiopathology
• Liver Cirrhosis/therapy
• Male
• Mice
• Mice, Transgenic
• Middle Aged
• Peptide Fragments/pharmacology
• Peptide Fragments/therapeutic use
• Rats
• Rats, Sprague-Dawley

The blood-brain barrier (BBB) dysfunction is an initial event of various neuroinflammatory diseases. However, the absence of reliable markers and mechanisms for BBB damage greatly limits the diagnosis and treatment of neuroinflammatory diseases. Soluble CD146 (sCD146) is mainly derived from vascular endothelial cells (ECs) and highly elevated in inflammatory settings. Based on a small cohort, our previous study showed that sCD146 is elevated in the cerebrospinal fluid (CSF) of multiple sclerosis (MS), which is accompanied with BBB damage. Nevertheless, whether sCD146 monitors and regulates the BBB dysfunction remains unknown.

Methods: Coupled serum and CSF samples from patients with or without neuroinflammatory diseases were collected via multicenter collaborations. sCD146 was measured by sandwich ELISA using anti-CD146 antibodies AA1 and AA98, both of which were generated in our laboratory. The correlations between sCD146 and other clinical parameters or inflammatory factors were analyzed by Spearman's correlation coefficient analysis. The role of sCD146 on BBB function was examined in an in vitro BBB model.

Results: Between July 20, 2011, and February 31, 2017, we collected coupled serum and CSF samples from 823 patients, of which 562 (68.3%) had neuroinflammatory diseases, 44 (5.3%) had remitting MS, and 217 (26.4%) had non-inflammatory neurological diseases (NIND). We found that sCD146 in CSF, but not in serum, is abnormally elevated in neuroinflammatory diseases (37.3 ± 13.3 ng/mL) compared with NIND (4.7 ± 2.9 ng/mL) and remitting MS (4.6 ± 3.5 ng/mL). Abnormally elevated CSF sCD146 is significantly correlated with the hyperpermeability-related clinical parameters of BBB and neuroinflammation-related factors. Moreover, CSF sCD146 shows higher sensitivity and specificity for evaluating BBB damage. Using an in vitro BBB model, we found that sCD146 impairs BBB function by promoting BBB permeability via an association with integrin αvβ1. Blocking integrin αvβ1 significantly attenuates sCD146-induced hyperpermeability of the BBB.

Conclusion: Our study provides convincing evidence that CSF sCD146 is a sensitive marker of BBB damage and neuroinflammation. Furthermore, sCD146 is actively involved in BBB dysfunction.

• blood-brain barrier damage and neuroinflammation.
• cerebrospinal fluid
• sCD146

• TEER
• blood brain barrier
• endothelial cells
• gene expression
• microvesicles
• neutrophils
• permeability

• Blood-Brain Barrier/cytology
• Blood-Brain Barrier/metabolism
• Capillary Permeability
• Cells, Cultured
• Endocytosis
• Endothelial Cells/metabolism
• Endothelium, Vascular/cytology
• Endothelium, Vascular/metabolism
• Extracellular Vesicles/metabolism
• Humans
• Neutrophils/metabolism

• MR/J004308/1 Medical Research Council
• G0900582 Medical Research Council
• ARUK-PhD2016-5 Alzheimer's Research UK
• G9901400 Medical Research Council
• G0300126 Medical Research Council

• 3D Alzheimer's disease model
• Alzheimer's disease
• blood–brain barrier

• R01 AG061891 NIA NIH HHS
• R01 AG062547 NIA NIH HHS
• R21 NS105027 NINDS NIH HHS
• RF1 AG048080 NIA NIH HHS
• Cure Alzheimer's Fund
• JPB Foundation

The major limitation of organ transplantation is the shortage of available organs. Xenotransplantation is considered to be an effective way to resolve the problem. Immune rejection is a major hurdle for the successful survival of pig xenografts in primate recipients. Cytokines play important roles in inflammation and many diseases including allotransplantation, however, their roles in xenotransplantation have been less well investigated.

We assessed the role of several cytokines in xenotransplantation using an in vitro model of human antibody-mediated complement-dependent cytotoxicity (CDC). Porcine aortic endothelial cells (PAECs) and porcine iliac endothelial cells (PIECs) were selected as target cells. The complement regulators (CD46, CD55 and CD59) and junction protein genes were assessed by real-time PCR, flow cytometry, or western-blotting assay. Flow cytometry assay was also used to evaluate C3 and C5b-9 deposition, as well as the extent of human IgM and IgG binding to PIECs. Gene silencing was used to reduce genes expression in PIECs. Gene overexpression was mediated by adenovirus or retrovirus.

Recombinant human TNF-α increased the cytotoxicity of PAECs and PIECs in a human antibody-mediated CDC model. Unexpectedly, we found that the expression of complement regulators (CD46, CD55 and CD59) increased in PIECs exposed to human TNF-α. Human TNF-α did not modify C3 or C5b-9 deposition on PIECs. The extent of human IgM and IgG binding to PIECs was not affected by human TNF-α. Human TNF-α decreased the expression of Occludin in PIECs. Gene silencing and overexpression assay suggested that Occludin was required for human TNF-α-mediated cytotoxicity of PIECs in this model. P38 gene silencing or inhibition of P38 signaling pathway with a specific inhibitor, SB203580, inhibited the reduction of Occludin expression induced by TNF-α, and suppressed TNF-α-augmented cytotoxicity of PIECs.

Our data suggest that human TNF-α increases the cytotoxicity of porcine endothelial cells in a human antibody-mediated CDC model by downregulating P38-dependent Occludin expression. Pharmacologic blockade of TNF-α is likely to increase xenograft survival in pig-to-primate organ xenotransplantation.

The online version of this article (10.1186/s12964-019-0386-7) contains supplementary material, which is available to authorized users.

• Antibody-mediated complement-dependent cytotoxicity
• P38
• Porcine endothelial cells
• TNF-α
• Xenotransplantation

• Antiretroviral drugs
• Dolutegravir
• Emtricitabine
• HIV
• Mass spectrometry
• Tenofovir

• Analytic Sample Preparation Methods
• Anti-HIV Agents/analysis
• Anti-HIV Agents/isolation & purification
• Brain/cytology
• Cell Line
• Chromatography, Liquid/methods
• Emtricitabine/analysis
• Emtricitabine/isolation & purification
• Endothelial Cells/cytology
• Heterocyclic Compounds, 3-Ring/analysis
• Heterocyclic Compounds, 3-Ring/isolation & purification
• Humans
• Intracellular Space/chemistry
• Linear Models
• Oxazines
• Piperazines
• Pyridones
• Reproducibility of Results
• Tandem Mass Spectrometry/methods
• Tenofovir/analysis
• Tenofovir/isolation & purification

• K02 DA027374 NIDA NIH HHS
• R21 DA045630 NIDA NIH HHS

• Alzheimer’s
• Amyloid-β peptide
• Azelnidipine
• NFκB
• cytosolic phospholipase A2
• endothelial cells

• APP/PS1 transgenic mouse
• Alzheimer’s disease
• blood-brain barrier
• brain endothelium
• nanoparticle
• pioglitazone

• Alzheimer Disease/drug therapy
• Amyloid beta-Protein Precursor/genetics
• Animals
• Blood-Brain Barrier/drug effects
• Cells, Cultured
• Disease Models, Animal
• Drug Carriers/chemistry
• Humans
• Hypoglycemic Agents/administration & dosage
• Hypoglycemic Agents/chemistry
• Hypoglycemic Agents/pharmacology
• In Vitro Techniques
• Male
• Memory Disorders/prevention & control
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Nanoparticles/administration & dosage
• Nanoparticles/chemistry
• PPAR gamma/agonists
• Pioglitazone
• Polyesters/chemistry
• Polyethylene Glycols/chemistry
• Presenilin-1/genetics
• Thiazolidinediones/administration & dosage
• Thiazolidinediones/chemistry
• Thiazolidinediones/pharmacology

• 3×Tg-AD mouse
• Amyloid plaque
• Neurofibrillary tangle
• Neuroinflammation
• Sex difference
• Spatial memory

• blood-brain barrier
• brain metastasis
• cell adhesion molecules signaling
• claudin-5
• permeability

Brain capillary endothelial cells form the blood-brain barrier (BBB), which is covered with basement membranes and is also surrounded by pericytes and astrocyte end-feet in the neurovascular unit. The BBB tightly regulates the molecular exchange between the blood flow and brain parenchyma, thereby regulating the homeostasis of the central nervous system (CNS). Thus, dysfunction of the BBB is likely involved in the pathogenesis of several neurological diseases, including Alzheimer’s disease (AD). While amyloid-β (Aβ) deposition and neurofibrillary tangle formation in the brain are central pathological hallmarks in AD, cerebrovascular lesions and BBB alteration have also been shown to frequently coexist. Although further clinical studies should clarify whether BBB disruption is a specific feature of AD pathogenesis, increasing evidence indicates that each component of the neurovascular unit is significantly affected in the presence of AD-related pathologies in animal models and human patients. Conversely, since some portions of Aβ are eliminated along the neurovascular unit and across the BBB, disturbing the pathways may result in exacerbated Aβ accumulation in the brain. Thus, current evidence suggests that BBB dysfunction may causatively and consequently contribute to AD pathogenesis, forming a vicious cycle between brain Aβ accumulation and neurovascular unit impairments during disease progression.

• amyloid-β
• astrocytes
• basement membrane
• cerebral amyloid angiopathy
• endothelial cells
• neurovascular unit
• pericytes
• tight junctions

• Albumins/cerebrospinal fluid
• Alzheimer Disease/complications
• Alzheimer Disease/metabolism
• Amyloid beta-Peptides/metabolism
• Animals
• Astrocytes/metabolism
• Basement Membrane/pathology
• Biological Transport
• Blood-Brain Barrier/metabolism
• Brain/metabolism
• Central Nervous System
• Cerebral Amyloid Angiopathy/metabolism
• Cerebrovascular Disorders/physiopathology
• Disease Progression
• Endothelial Cells
• Homeostasis
• Humans
• Peptide Fragments/metabolism
• Pericytes/metabolism
• Serum Albumin
• Tight Junctions

• R01 AG051574 NIA NIH HHS

• 5xFAD
• Alzheimer’s disease
• BBB
• Crocus Sativus extract
• amyloid-β clearance
• crocin
• neuroinflammation

• Alzheimer’s disease
• amyloid-β peptides
• blood-brain barrier
• cyclooxygenase-2
• cytokine
• fibrillar amyloid-β peptides
• luteolin
• mitogen-activated protein kinases
• nuclear factor κB

• Amyloid beta-Peptides/adverse effects
• Apoptosis/drug effects
• Astrocytes/cytology
• Astrocytes/drug effects
• Astrocytes/immunology
• Blood-Brain Barrier/drug effects
• Blood-Brain Barrier/immunology
• Brain/blood supply
• Brain/cytology
• Brain/immunology
• Cell Survival
• Cells, Cultured
• Coculture Techniques
• Cytokines/metabolism
• Endothelial Cells/drug effects
• Endothelial Cells/immunology
• Gene Expression Regulation/drug effects
• Humans
• Luteolin/pharmacology
• MAP Kinase Signaling System/drug effects
• Models, Biological
• NF-kappa B/metabolism
• Neuroprotective Agents/pharmacology
• Peptide Fragments/adverse effects

• Alzheimer’s
• angiogenesis
• blood–brain barrier
• cerebrovascular disease
• endothelium
• pericytes

• amyloid-β
• blood-brain barrier
• clearance
• hCMEC/D3
• in vitro model

• Amyloid-β
• blood-brain barrier
• high-throughput screening
• permeability
• repurposing

• Amyloid beta-Peptides/chemistry
• Amyloid beta-Peptides/toxicity
• Animals
• Biological Transport/drug effects
• Blood-Brain Barrier/drug effects
• Brain/cytology
• Cell Line, Transformed
• Claudin-5/metabolism
• Coculture Techniques
• Drug Repositioning/methods
• Endothelial Cells/drug effects
• In Vitro Techniques
• Libraries, Special
• Mice
• Models, Biological
• Peptide Fragments
• Permeability/drug effects

• P20 GM103424 NIGMS NIH HHS
• R15 NS091934 NINDS NIH HHS

Astrocytes and cerebral endothelial cells are important components of the blood-brain barrier (BBB). Disruption to this barrier through inflammation is a major contributor to Alzheimer’s disease (AD) pathology. The amyloid beta (Aβ) protein is known to exist in several forms and is a key modulator of AD that is known to cause inflammation and changes to BBB function. While one of these forms, fibrillary Aβ (fAβ), is known to cause endothelial cell death at the BBB, no studies have looked specifically at its role on inflammation in a model of the human BBB.

To determine if fAβ is inflammatory to the human BBB. As statins have been shown to be anti-inflammatory and protective in AD, we also tested if these could inhibit the inflammatory effect of fAβ.

Using cultured cerebral endothelial cells and astrocytes we determined changes in cytokine release, cell toxicity and barrier function in response to fibrillary β-amyloid_1–42 (fAβ_1–42) alone and in combination with statins.

fAβ_1–42 induced inflammatory cytokine release from endothelial cells in the absence of cell toxicity. It also induced astrocyte cytokine release and cell death and caused a loss of barrier integrity. Statin treatment inhibited all of these effects.

We conclude that fAβ_1–42 has both inflammatory and cytotoxic effects on the BBB and the protective effect of statins in AD may in part be through inhibiting these effects.

• Amyloid beta-Peptides/antagonists & inhibitors
• Amyloid beta-Peptides/pharmacology
• Anti-Inflammatory Agents, Non-Steroidal/pharmacology
• Anticholesteremic Agents/pharmacology
• Astrocytes/cytology
• Astrocytes/drug effects
• Astrocytes/metabolism
• Blood-Brain Barrier/drug effects
• Cell Death/drug effects
• Cell Line
• Chemokine CCL2/antagonists & inhibitors
• Chemokine CCL2/metabolism
• Chemokine CCL5/antagonists & inhibitors
• Chemokine CCL5/metabolism
• Coculture Techniques
• Endothelial Cells/cytology
• Endothelial Cells/drug effects
• Endothelial Cells/metabolism
• Humans
• Interleukin-6/antagonists & inhibitors
• Interleukin-6/metabolism
• Interleukin-8/antagonists & inhibitors
• Interleukin-8/metabolism
• Lovastatin/pharmacology
• Models, Biological
• Peptide Fragments/antagonists & inhibitors
• Peptide Fragments/pharmacology
• Simvastatin/pharmacology
• Vascular Endothelial Growth Factor A/antagonists & inhibitors
• Vascular Endothelial Growth Factor A/metabolism

• Maurice and Phyllis Paykel Trust
• Lottery Health New Zealand

• Blood–brain barrier
• astrocytes
• endothelium
• pericytes
• stem cells

Cerebrovascular disease (CVD) and Alzheimer’s disease (AD) have more in common than their association with ageing. They share risk factors and overlap neuropathologically. Most patients with AD have Aβ amyloid angiopathy and degenerative changes affecting capillaries, and many have ischaemic parenchymal abnormalities. Structural vascular disease contributes to the ischaemic abnormalities in some patients with AD. However, the stereotyped progression of hypoperfusion in this disease, affecting first the precuneus and cingulate gyrus, then the frontal and temporal cortex and lastly the occipital cortex, suggests that other factors are more important, particularly in early disease. Whilst demand for oxygen and glucose falls in late disease, functional MRI, near infrared spectroscopy to measure the saturation of haemoglobin by oxygen, and biochemical analysis of myelin proteins with differential susceptibility to reduced oxygenation have all shown that the reduction in blood flow in AD is primarily a problem of inadequate blood supply, not reduced metabolic demand. Increasing evidence points to non-structural vascular dysfunction rather than structural abnormalities of vessel walls as the main cause of cerebral hypoperfusion in AD. Several mediators are probably responsible. One that is emerging as a major contributor is the vasoconstrictor endothelin-1 (EDN1). Whilst there is clearly an additive component to the clinical and pathological effects of hypoperfusion and AD, experimental and clinical observations suggest that the disease processes also interact mechanistically at a cellular level in a manner that exacerbates both. The elucidation of some of the mechanisms responsible for hypoperfusion in AD and for the interactions between CVD and AD has led to the identification of several novel therapeutic approaches that have the potential to ameliorate ischaemic damage and slow the progression of neurodegenerative disease.

• Ageing
• Alzheimer’s disease
• Cerebrovascular disease
• Endothelin-1
• Hypoperfusion
• Myelin proteins

• Aging/pathology
• Alzheimer Disease/complications
• Alzheimer Disease/diagnostic imaging
• Animals
• Blood Vessels/diagnostic imaging
• Blood Vessels/pathology
• Brain/diagnostic imaging
• Brain/pathology
• Catenins
• Cerebrovascular Disorders/diagnostic imaging
• Cerebrovascular Disorders/etiology
• Humans
• Delta Catenin

• MC_PC_14095 Medical Research Council
• MR/K015397/1 Medical Research Council
• PG/10/47/28285 British Heart Foundation
• Alzheimer’s Research UK
• BRACE (Bristol Research into Alzheimer's and Care of the Elderly)

• Alzheimer's disease
• Amyloid precursor protein
• High glucose
• Human umbilical vein endothelial cells
• Junctional permeability

• alzheimer’s disease
• blood-brain barrier
• tight junctions
• claudin-5
• occludin
• rna interference
• amyloid-beta

• R01 AG046275 NIA NIH HHS
• Science Foundation Ireland
• National Institutes of Health
• BrightFocus Foundation (US)

• Aging
• Alzheimer’s disease
• Blood–brain barrier
• Glial activation
• Neurodegeneration
• Vascular dysfunction

• Alzheimer’s disease
• Amyloid β
• Astrocyte
• Microglia
• Neuroinflammation
• T cell

Cerebrovascular accumulation of amyloid-β (Aβ) peptides in Alzheimer's disease (AD) may contribute to disease progression through Aβ-induced microvascular endothelial pathogenesis. Pinocembrin has been shown to have therapeutic effects in AD models. These effects correlate with preservation of microvascular function, but the effect on endothelial cells under Aβ-damaged conditions is unclear. The present study focuses on the in vitro protective effect of pinocembrin on fibrillar Aβ₁₋₄₀ (fAβ₁₋₄₀) injured human brain microvascular endothelial cells (hBMECs) and explores potential mechanisms. The results demonstrate that fAβ₁₋₄₀-induced cytotoxicity in hBMECs can be rescued by pinocembrin treatment. Pinocembrin increases cell viability, reduces the release of LDH, and relieves nuclear condensation. The mechanisms of this reversal from Aβ may be associated with the inhibition of inflammatory response, involving inhibition of MAPK activation, downregulation of phosphor-IKK level, relief of IκBα degradation, blockage of NF-κB p65 nuclear translocation, and reduction of the release of proinflammatory cytokines. Pinocembrin does not show obvious effects on regulating the redox imbalance after exposure to fAβ₁₋₄₀. Together, the suppression of MAPK and the NF-κB signaling pathways play a significant role in the anti-inflammation of pinocembrin in hBMECs subjected to fAβ₁₋₄₀. This may serve as a therapeutic agent for BMEC protection in Alzheimer's-related deficits.

• Alzheimer's disease
• Amyloid-β
• Blood–brain barrier
• Clearance

• ATP Binding Cassette Transporter, Subfamily B/metabolism
• Amyloid beta-Peptides/chemistry
• Amyloid beta-Peptides/pharmacology
• Biological Transport
• Blood-Brain Barrier/drug effects
• Blood-Brain Barrier/metabolism
• Blotting, Western
• Brain/metabolism
• Brain/pathology
• Cells, Cultured
• Dimerization
• Endothelium, Vascular/metabolism
• Endothelium, Vascular/pathology
• Humans
• Low Density Lipoprotein Receptor-Related Protein-1/metabolism
• Microvessels/metabolism
• Microvessels/pathology
• Plaque, Amyloid/metabolism
• Plaque, Amyloid/pathology
• Receptor for Advanced Glycation End Products
• Receptors, Immunologic/metabolism

• P20 GM103424 NIGMS NIH HHS
• P20GM103424 NIGMS NIH HHS

We have adapted an in vitro model of the human blood-brain barrier, the immortalized human cerebral microvascular endothelial cells (hCMEC/D3), to quantitatively measure protein transcytosis. After validating the receptor-mediated transport using transferrin, the system was used to measure transcytosis rates of antibodies directed against potential brain shuttle receptors. While an antibody to the insulin-like growth factor 1 receptor (IGF1R) was exclusively recycled to the apical compartment, the fate of antibodies to the transferrin receptor (TfR) was determined by their relative affinities at extracellular and endosomal pH. An antibody with reduced affinity at pH5.5 showed significant transcytosis, while pH-independent antibodies of comparable affinities at pH 7.4 remained associated with intracellular vesicular compartments and were finally targeted for degradation.

• Antibodies/immunology
• Antibodies/metabolism
• Antigens, CD/immunology
• Blood-Brain Barrier/metabolism
• Cell Line
• Humans
• Hydrogen-Ion Concentration
• Receptor, IGF Type 1/immunology
• Receptors, Transferrin/immunology
• Transcytosis

Interleukin-8 (IL-8) is a common inflammatory factor, which involves in various non-specific pathological processes of inflammation. It has been found that increased endothelial permeability accompanied with high expression of IL-8 at site of injured endothelium and atherosclerotic plaque at early stages, suggesting that IL-8 participated in regulating endothelial permeability in the developing processes of vascular disease. The purpose of this study is to investigate the regulation effects of IL-8 on the vascular endothelial permeability, and the mRNA and protein expression of tight junction components (i.e., ZO-1, Claudin-5 and Occludin). Endothelial cells were stimulated by IL-8 with the dose of 50, 100 and 200 ng/mL, and duration of 2, 4, 6, 8h, respectively. The mRNA and protein expression level of tight junction components with IL-8 under different concentration and duration was examined by RT-PCR and Western blot, respectively. Meanwhile, the integrins induced focal adhesions event with IL-8 stimulation was also investigated. The results showed that IL-8 regulated the permeability of endothelium by down-regulation of tight junction in a dose- and time-dependence manner, but was not by integrins induced focal adhesions. This finding reveals the molecular mechanism in the increase of endothelial cell permeability induced by IL-8, which is expected to provide a new idea as a therapeutic target in vascular diseases.

• Claudin-5
• Endothelial permeability
• IL-8
• Occludin
• Tight junction
• ZO-1.

As fundamental research advances, it is becoming increasingly clear that a clinically expressed disease implies a mixture of intertwining molecular disturbances. Oxidative stress is one of such pathogenic pathways involved in virtually all central nervous system pathologies, infectious, inflammatory, or degenerative in nature. Since brain homeostasis largely depends on integrity of blood-brain barrier (BBB), many studies focused lately on BBB alteration in a wide spectrum of brain diseases. The proper two-way molecular transfer through BBB depends on several factors, including the functional status of its tight junction (TJ) complexes of proteins sealing neighbour endothelial cells. Although there is abundant experimental work showing that oxidative stress associates BBB permeability alteration, less is known about its implications, at molecular level, in TJ protein expression or TJ-related cell signalling. In this paper, oxidative stress is presented as a common pathway for different brain pathogenic mechanisms which lead to BBB dysregulation. We revise here oxidative-induced molecular mechanisms of BBB disruption and TJ protein expression alteration, in relation to ageing and neurodegeneration.

The Blood–brain barrier (BBB), present at the level of the endothelium of cerebral blood vessels, selectively restricts the blood-to-brain paracellular diffusion of compounds; it is mandatory for cerebral homeostasis and proper neuronal function. The barrier properties of these specialized endothelial cells notably depend on tight junctions (TJs) between adjacent cells: TJs are dynamic structures consisting of a number of transmembrane and membrane-associated cytoplasmic proteins, which are assembled in a multimolecular complex and acting as a platform for intracellular signaling. Although the structural composition of these complexes has been well described in the recent years, our knowledge about their functional regulation still remains fragmentary. Importantly, pericytes, embedded in the vascular basement membrane, and perivascular microglial cells, astrocytes and neurons contribute to the regulation of endothelial TJs and BBB function, altogether constituting the so-called neurovascular unit.

The present review summarizes our current understanding of the structure and functional regulation of endothelial TJs at the BBB. Accumulating evidence points to a correlation between BBB dysfunction, alteration of TJ complexes and progression of a variety of CNS diseases, such as stroke, multiple sclerosis and brain tumors, as well as neurodegenerative diseases like Parkinson’s and Alzheimer’s diseases. Understanding how TJ integrity is controlled may thus help improve drug delivery across the BBB and the design of therapeutic strategies for neurological disorders.

• Amyloid beta-Peptides/metabolism
• Animals
• Cerebral Amyloid Angiopathy/metabolism
• Cerebral Amyloid Angiopathy/pathology
• Cerebrovascular Circulation
• Endothelium, Vascular/metabolism
• Endothelium, Vascular/pathology
• Humans
• Peptide Fragments/metabolism

• P50 AG023501 NIA NIH HHS
• R01 AG040311 NIA NIH HHS
• R01AG040311-01A1 NIA NIH HHS
• P50 AG023501-06 NIA NIH HHS

AIM: To investigate the effect of emodin on pancreatic claudin-5 and occludin expression, and pancreatic paracellular permeability in acute pancreatitis (AP).

METHODS: Experimental pancreatitis was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. Emodin was injected via the external jugular vein 0 or 6 h after induction of AP. Rats from sham operation and AP groups were injected with normal saline at the same time. Samples of pancreas were obtained 6 or 12 h after drug administration. Pancreatic morphology was examined with hematoxylin and eosin staining. Pancreatic edema was estimated by measuring tissue water content. Tumor necrosis factor (TNF)-α and interleukin (IL)-6 level were measured by enzyme-linked immunosorbent assay. Pancreatic paracellular permeability was assessed by tissue dye extravasation. Expression of pancreatic claudin-5 and occludin was examined by immunohistology, quantitative real-time reverse transcriptase polymerase chain reaction and western blotting.

RESULTS: Pancreatic TNF-α and IL-6 levels, wet/dry ratio, dye extravasation, and histological score were significantly elevated at 3, 6 and 12 h following sodium taurocholate infusion; treatment with emodin prevented these changes at all time points. Immunostaining of claudin-5 and occludin was detected in rat pancreas, which was distributed in pancreatic acinar cells, ductal cells and vascular endothelial cells, respectively. Sodium taurocholate infusion significantly decreased pancreatic claudin-5 and occludin mRNA and protein levels at 3, 6 and 12 h, and that could be promoted by intravenous administration of emodin at all time points.

CONCLUSION: These results demonstrate that emodin could promote pancreatic claudin-5 and occludin expression, and reduce pancreatic paracellular permeability.

• Acute pancreatitis
• Paracellular permeability
• Emodin
• Claudin
• Occludin

The hemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia and renal dysfunction. The typical form of HUS is generally associated with infections by Gram-negative Shiga toxin (Stx)-producing Escherichia coli (STEC). Endothelial dysfunction induced by Stx is central, but bacterial lipopolysaccharide (LPS) and neutrophils (PMN) contribute to the pathophysiology. Although renal failure is characteristic of this syndrome, neurological complications occur in severe cases and is usually associated with death. Impaired blood-brain barrier (BBB) is associated with damage to cerebral endothelial cells (ECs) that comprise the BBB. Astrocytes (ASTs) are inflammatory cells in the brain and determine the BBB function. ASTs are in close proximity to ECs, hence the study of the effects of Stx1 and LPS on ASTs, and the influence of their response on ECs is essential. We have previously demonstrated that Stx1 and LPS induced activation of rat ASTs and the release of inflammatory factors such as TNF-α, nitric oxide and chemokines. Here, we demonstrate that rat ASTs-derived factors alter permeability of ECs with brain properties (HUVECd); suggesting that functional properties of BBB could also be affected. Additionally, these factors activate HUVECd and render them into a proagregant state promoting PMN and platelets adhesion. Moreover, these effects were dependent on ASTs secreted-TNF-α. Stx1 and LPS-induced ASTs response could influence brain ECs integrity and BBB function once Stx and factors associated to the STEC infection reach the brain parenchyma and therefore contribute to the development of the neuropathology observed in HUS.

Hemolytic-uremic syndrome (HUS) is generally caused by Shiga toxin (Stx)-producing Escherichia coli but bacterial lipopolysaccharide (LPS) and neutrophils (PMN) contribute to the pathophysiology. Acute renal failure is the main feature of HUS, but in severe cases, patients develop neurological complications, which are usually associated with death. Although the mechanisms of neurological damage remain uncertain, alterations/injury of brain endothelial cells (ECs) which constitute the blood-brain barrier (BBB) is clear. Astrocytes (ASTs) are inflammatory cells enclosing ECs and are responsible of the normal function of the barrier. We have recently demonstrated that Stx1, one of the most common types of Stx, induce an inflammatory response in LPS-treated ASTs. We then study the effects of factors released by ASTs in response to LPS and/or Stx1 on brain-like ECs. We demonstrate that Stx1 induces in LPS-treated ASTs the release of factors that alter brain properties in ECs, including the permeability; turning them more susceptible to Stx1 toxic effects. Furthermore, they activate ECs, neutrophils (PMN) and platelets and render ECs into a proagregant state promoting PMN and platelet adhesion. Our results suggest that ASTs could influence brain ECs integrity and BBB function once Stx in combination with bacterial factors reach the brain parenchyma.