scholarly journals A host-gut microbial co-metabolite of aromatic amino acids, p-cresol glucuronide, promotes blood-brain barrier integrity in vivo

2022 ◽  
Author(s):  
Andrew V Stachulski ◽  
Tobias B-A Knausenberger ◽  
Sita N Shah ◽  
Lesley Hoyles ◽  
Simon McArthur
Keyword(s):  
Amino Acids ◽  
Blood Brain Barrier ◽  
Aromatic Amino Acids ◽  
Biologically Active ◽  
Brain Barrier ◽  
Whole Brain ◽  
Blood Brain ◽  
Bbb Permeability

Purpose: The sequential activity of gut microbial and host processes can exert a powerful modulatory influence on dietary components, as exemplified by the metabolism of the amino acids tyrosine and phenylalanine to p-cresol by gut microbes, and then to p-cresol glucuronide (pCG) by host enzymes. Although such glucuronide conjugates are classically thought to be biologically inert, there is accumulating evidence that this may not always be the case. We investigated the activity of pCG, studying its interactions with the cerebral vasculature and the brain in vitro and in vivo. Methods: Male C57Bl/6J mice were used to assess blood-brain barrier (BBB) permeability and whole brain transcriptomic changes in response to pCG treatment. Effects were then further explored using the human cerebromicrovascular endothelial cell line hCMEC/D3, assessing paracellular permeability, transendothelial electrical resistance and barrier protein expression. Results: Mice exposed to pCG showed reduced BBB permeability and significant changes in whole brain transcriptome expression. Surprisingly, treatment of hCMEC/D3 cells with pCG had no notable effects until co-administered with bacterial lipopolysaccharide, at which point it was able to prevent the permeabilising effects of endotoxin. Further analysis suggested that pCG acts as an antagonist at the principal lipopolysaccharide receptor TLR4. Conclusion: The amino acid phase II metabolic product pCG is biologically active at the BBB, highlighting the complexity of gut microbe to host communication and the gut-brain axis.

scholarly journals Yuzu and Hesperidin Ameliorate Blood-Brain Barrier Disruption during Hypoxia via Antioxidant Activity

Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 843
Author(s):  
Bo Kyung Lee ◽  
Soo-Wang Hyun ◽  
Yi-Sook Jung
Keyword(s):  
Endothelial Cell ◽  
Blood Brain Barrier ◽  
Cell Model ◽  
Antioxidant Properties ◽  
Brain Barrier ◽  
Blood Brain ◽  
In Vivo Animal Model ◽  
Bbb Permeability

Yuzu and its main component, hesperidin (HSP), have several health benefits owing to their anti-inflammatory and antioxidant properties. We examined the effects of yuzu and HSP on blood–brain barrier (BBB) dysfunction during ischemia/hypoxia in an in vivo animal model and an in vitro BBB endothelial cell model, and also investigated the underlying mechanisms. In an in vitro BBB endothelial cell model, BBB permeability was determined by measurement of Evans blue extravasation in vivo and in vitro. The expression of tight junction proteins, such as claudin-5 and zonula occludens-1 (ZO-1), was detected by immunochemistry and western blotting, and the reactive oxygen species (ROS) level was measured by 2′7′-dichlorofluorescein diacetate intensity. Yuzu and HSP significantly ameliorated the increase in BBB permeability and the disruption of claudin-5 and ZO-1 in both in vivo and in vitro models. In bEnd.3 cells, yuzu and HSP were shown to inhibit the disruption of claudin-5 and ZO-1 during hypoxia, and the protective effects of yuzu and HSP on claudin-5 degradation seemed to be mediated by Forkhead box O 3a (FoxO3a) and matrix metalloproteinase (MMP)-3/9. In addition, well-known antioxidants, trolox and N-acetyl cysteine, significantly attenuated the BBB permeability increase, disruption of claudin-5 and ZO-1, and FoxO3a activation during hypoxia, suggesting that ROS are important mediators of BBB dysfunction during hypoxia. Collectively, these results indicate that yuzu and HSP protect the BBB against dysfunction via maintaining integrity of claudin-5 and ZO-1, and these effects of yuzu and HSP appear to be a facet of their antioxidant properties. Our findings may contribute to therapeutic strategies for BBB-associated neurodegenerative diseases.

scholarly journals Increase in Blood-Brain Barrier (BBB) Permeability Is Regulated by MMP3 via the ERK Signaling Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Qin Zhang ◽  
Mei Zheng ◽  
Cristian E. Betancourt ◽  
Lifeng Liu ◽  
Albert Sitikov ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Erk Signaling ◽  
Anesthesia Induction ◽  
Matrix Metalloproteinase 3 ◽  
Blood Brain ◽  
Bbb Permeability

Background. The blood-brain barrier (BBB) regulates the exchange of molecules between the brain and peripheral blood and is composed primarily of microvascular endothelial cells (BMVECs), which form the lining of cerebral blood vessels and are linked via tight junctions (TJs). The BBB is regulated by components of the extracellular matrix (ECM), and matrix metalloproteinase 3 (MMP3) remodels the ECM’s basal lamina, which forms part of the BBB. Oxidative stress is implicated in activation of MMPs and impaired BBB. Thus, we investigated whether MMP3 modulates BBB permeability. Methods. Experiments included in vivo assessments of isoflurane anesthesia and dye extravasation from brain in wild-type (WT) and MMP3-deficient (MMP3-KO) mice, as well as in vitro assessments of the integrity of monolayers of WT and MMP3-KO BMVECs and the expression of junction proteins. Results. Compared to WT mice, measurements of isoflurane usage and anesthesia induction time were higher in MMP3-KO mice and lower in WT that had been treated with MMP3 (WT+MMP3), while anesthesia emergence times were shorter in MMP3-KO mice and longer in WT+MMP3 mice than in WT. Extravasation of systemically administered dyes was also lower in MMP3-KO mouse brains and higher in WT+MMP3 mouse brains, than in the brains of WT mice. The results from both TEER and Transwell assays indicated that MMP3 deficiency (or inhibition) increased, while MMP3 upregulation reduced barrier integrity in either BMVEC or the coculture. MMP3 deficiency also increased the abundance of TJs and VE-cadherin proteins in BMVECs, and the protein abundance declined when MMP3 activity was upregulated in BMVECs, but not when the cells were treated with an inhibitor of extracellular signal related-kinase (ERK). Conclusion. MMP3 increases BBB permeability following the administration of isoflurane by upregulating the ERK signaling pathway, which subsequently reduces TJ and VE-cadherin proteins in BMVECs.

Modulators of Blood-Brain Barrier (BBB) Permeability: In Vitro and in Vivo Drug Transport to the Brain

2001 ◽  
pp. 83-97
Author(s):  
A. G. De Boer ◽  
P. J. Gaillard ◽  
I. C. J. Van Der Sandt ◽  
E. C. M. De Lange ◽  
D. D. Breimer
Keyword(s):  
Blood Brain Barrier ◽  
Drug Transport ◽  
Brain Barrier ◽  
Blood Brain ◽  
Bbb Permeability ◽  
The Brain

scholarly journals Blood–Brain Barrier Permeability: Is 5-Hydroxytryptamine Receptor Type 4 a Game Changer?

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1856
Author(s):  
Guillaume Becker ◽  
Sylvia Da Silva ◽  
Amelia-Naomi Sabo ◽  
Maria Cristina Antal ◽  
Véronique Kemmel ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Serotonin Receptor ◽  
Brain Parenchyma ◽  
The Body ◽  
Brain Barrier ◽  
Blood Brain ◽  
Junction Protein ◽  
Bbb Permeability

Serotonin affects many functions in the body, both in the central nervous system (CNS) and the periphery. However, its effect on the blood–brain barrier (BBB) in separating these two worlds has been scarcely investigated. The aim of this work was to characterize the serotonin receptor 5-HT4 in the hCMEC/D3 cell line, in the rat and the human BBB. We also examined the effect of prucalopride, a 5-HT4 receptor agonist, on the permeability of the hCMEC/D3 in an in vitro model of BBB. We then confirmed our observations by in vivo experiments. In this work, we show that the 5-HT4 receptor is expressed by hCMEC/D3 cells and in the capillaries of rat and human brains. Prucalopride increases the BBB permeability by downregulating the expression of the tight junction protein, occludin. This effect is prevented by GR113808, a 5-HT4 receptor antagonist, and is mediated by the Src/ERK1/2 signaling pathway. The canonical G-protein-dependent pathway does not appear to be involved in this phenomenon. Finally, the administration of prucalopride increases the diffusion of Evans blue in the rat brain parenchyma, which is synonymous with BBB permeabilization. All these data indicate that the 5-HT4 receptor contributes to the regulation of BBB permeability.

scholarly journals LC–MS/MS-based in vitro and in vivo investigation of blood–brain barrier integrity by simultaneous quantitation of mannitol and sucrose

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Behnam Noorani ◽  
Ekram Ahmed Chowdhury ◽  
Faleh Alqahtani ◽  
Yeseul Ahn ◽  
Dhavalkumar Patel ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Stable Isotope ◽  
Blood Brain Barrier ◽  
Critical Role ◽  
Brain Barrier ◽  
Uptake Mechanism ◽  
Blood Brain ◽  
Bbb Permeability

Abstract Background Understanding the pathophysiology of the blood brain–barrier (BBB) plays a critical role in diagnosis and treatment of disease conditions. Applying a sensitive and specific LC–MS/MS technique for the measurement of BBB integrity with high precision, we have recently introduced non-radioactive [13C12]sucrose as a superior marker substance. Comparison of permeability markers with different molecular weight, but otherwise similar physicochemical properties, can provide insights into the uptake mechanism at the BBB. Mannitol is a small hydrophilic, uncharged molecule that is half the size of sucrose. Previously only radioactive [3H]mannitol or [14C]mannitol has been used to measure BBB integrity. Methods We developed a UPLC–MS/MS method for simultaneous analysis of stable isotope-labeled sucrose and mannitol. The in vivo BBB permeability of [13C6]mannitol and [13C12]sucrose was measured in mice, using [13C6]sucrose as a vascular marker to correct for brain intravascular content. Moreover, a Transwell model with induced pluripotent stem cell-derived brain endothelial cells was used to measure the permeability coefficient of sucrose and mannitol in vitro both under control and compromised (in the presence of IL-1β) conditions. Results We found low permeability values for both mannitol and sucrose in vitro (permeability coefficients of 4.99 ± 0.152 × 10−7 and 3.12 ± 0.176 × 10−7 cm/s, respectively) and in vivo (PS products of 0.267 ± 0.021 and 0.126 ± 0.025 µl g−1 min−1, respectively). Further, the in vitro permeability of both markers substantially increased in the presence of IL-1β. Corrected brain concentrations (Cbr), obtained by washout vs. vascular marker correction, were not significantly different for either mannitol (0.071 ± 0.007 and 0.065 ± 0.009 percent injected dose per g) or sucrose (0.035 ± 0.003 and 0.037 ± 0.005 percent injected dose per g). These data also indicate that Cbr and PS product values of mannitol were about twice the corresponding values of sucrose. Conclusions We established a highly sensitive, specific and reproducible approach to simultaneously measure the BBB permeability of two classical low molecular weight, hydrophilic markers in a stable isotope labeled format. This method is now available as a tool to quantify BBB permeability in vitro and in vivo in different disease models, as well as for monitoring treatment outcomes.

Abstract 544: Increase in Isoflurane-mediated Blood-brain-barrier (bbb) Permeability is Regulated by Mmp3 via the Erk Signal Pathway

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Rongxue Wu ◽  
Mei Zheng ◽  
Lifeng Liu ◽  
Cristian Betancourt ◽  
Albert Sitikov ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Control Group ◽  
Anesthesia Induction ◽  
Anesthetic Effect ◽  
Blood Brain ◽  
Junctional Protein ◽  
Bbb Permeability

Introduction: The blood-brain barrier (BBB) normally maintains the CNS microenvironment. The effect of isoflurane, widely used in clinical anesthesia, on the BBB permeability has not been well studied. Matrix metalloproteinase 3 (MMP3) is implicated in the disruption of BBB. However, the direct role for MMP3 in regulating BBB and the underlying molecular mechanism has not yet been elucidated. We hypothesized that MMP3 plays a critical role in isoflurane mediated increase in BBB permeability. Methods: We used MMP3 deficient (MMP3 -/- ) mice and its littermate, wild-type (MMP3 +/+ ), as a control. Animals were assigned to either vehicle-air or isoflurane in 3 different groups: control, MMP3 -/- and control+MMP3 administration. We evaluated the anesthetic effect of isoflurane by the time of anesthesia induction, emergency time and volume of isoflurane. MMP3 levels were measured in different organs. We monitored the permeability of mouse BBB through in vivo (Evans blue dye extravasation, Sodium-FITC, and brain water content) and an in vitro model of BBB (Electrical cell impedance sensor assay and transwell permeability assay). To determine the mechanism of MMP3 on BBB permeability, we also used an ERK-inhibitor. Expression of the endothelial tight junctional protein was detected by both western blot and immunofluorescence staining. Results: The use of MMP3 increased the anesthetic sensitivity of isoflurane compared with the control group. In contrast, MMP3 KO mice displayed significantly longer induction time, higher isoflurane usage volume, and lower emergency time. Data showed that MMP3 increased BBB permeability in both in vivo and in vitro experiments, which is associated with a reduction in occluding, ZO-1 and claudin-5. We found mmp3 levels had negative correlations with tight junctional proteins and positive associations with p-ERK. Moreover, the use of an ERK-inhibitor abolished the effect of MMP3 on the junctional protein and in vitro BBB permeability. Conclusion: Our data suggest that MMP3 is required for modulation of isoflurane mediated BBB permeability by the reduction of tight junctional protein expression via the ERK pathway. Thus, mmp3 enhances the anesthetic effect of isoflurane, while the deletion of MMP3 protects against BBB disruption.

scholarly journals C-Type Natriuretic Peptide Modulates Permeability of the Blood–Brain Barrier

2014 ◽  
Vol 34 (4) ◽  
pp. 589-596 ◽  
Author(s):  
Manoj Bohara ◽  
Yuki Kambe ◽  
Tetsuya Nagayama ◽  
Hiroshi Tokimura ◽  
Kazunori Arita ◽  
...  
Keyword(s):  
Natriuretic Peptide ◽  
Blood Brain Barrier ◽  
Messenger Rna ◽  
Brain Barrier ◽  
Sodium Fluorescein ◽  
Blood Brain ◽  
Protein Expressions ◽  
Bbb Permeability

C-type natriuretic peptide (CNP) is abundant in brain and is reported to exert autocrine function in vascular cells, but its effect on blood–brain barrier (BBB) permeability has not been clarified yet. Here, we examined this effect. Transendothelial electrical resistance (TEER) of in vitro BBB model, composed of bovine brain microvascular endothelial cells and astrocytes, was significantly dose dependently decreased by CNP (1, 10, and 100 nmol/L). C-type natriuretic peptide treatment reduced both the messenger RNA (mRNA) and protein expressions of tight junction (TJ) protein zonula occludens-1 (ZO-1). The effects on TEER, mRNA, and protein expressions of ZO-1 were mimicked by cyclic GMP (cGMP) analog 8-bromo-cGMP (1  μmol/L) and reversed by protein kinase G (PKG) inhibitor Rp-8-CPT-cGMPS (100  μmol/L), thus implying the role of PKG and cGMP signaling in BBB function. Transcription factor JunD knockdown by small interfering RNA resulted in no change of permeability by CNP. In vivo study of mouse brain by fluorimetric analysis with intravenous administration of sodium fluorescein (40 mg/kg) also showed a significant increase in BBB permeability by CNP (10 nmol/kg, intravenously). These findings suggest that CNP modulates the BBB permeability by altering ZO-1 expression.

scholarly journals β-Amyloid Protein Induces Mitophagy-Dependent Ferroptosis Through the CD36/PINK/PARKIN Pathway Leading to Blood-Brain Barrier Destruction in Alzheimer's Disease

2021 ◽  
Author(s):  
li Jianhua ◽  
Li mengyu ◽  
Ge Yangyang ◽  
Chen Jiayi ◽  
Ma Jiamin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Mechanism ◽  
Blood Brain Barrier ◽  
Amyloid Β ◽  
Brain Barrier ◽  
Blood Brain ◽  
Bbb Permeability

Abstract Background Blood-brain barrier (BBB) dysfunction may occur in the onset of Alzheimer's disease (AD). While pericytes are a vital part of the neurovascular unit and the BBB, acting as the gatekeeper of the BBB. Amyloid β (Aβ) deposition and neurofibrillary tangles in the brain are the central pathological features of AD. CD36 promotes vascular amyloid deposition and leads to vascular brain damage, neurovascular dysfunction, and cognitive deficits. However, the molecular mechanism in destroying pericytes of the BBB are still unclear. Objectives To investigate the effect of low-dose Aβ1-40 administration on pericyte outcome and BBB injury molecular mechanism. Methods We selected 6-month-old and 9-month-old APP/PS1 mice and wild-type (WT) mice of the same strain, age, and sex as controls. We assessed the BBB by PET/CT. Brain pericytes were extracted and cocultured with endothelial cells (bEnd.3) to generate an in vitro BBB model to observe the effect of Aβ1-40 on the BBB. Furthermore, we explored the intracellular degradation and related molecular mechanisms of Aβ1-40 after being engulfed in cells through CD36. Results BBB permeability and the number of pericytes decreased in APP/PS1 mice. Aβ1-40 increases the permeability of the BBB in an in vivo model and downregulates the expression of CD36, which reversed the Aβ-induced changes in BBB permeability. Aβ1-40 was phagocytized in pericytes with high expression of CD36. We observed that this molecule inhibited pericyte proliferation, caused mitochondrial damage, and increased mitophagy. Finally, we confirmed that Aβ1-40 induced pericyte mitophagy-dependent ferroptosis through the CD36/PINK1/Parkin pathway. Conclusions PDGFRβ (a marker of pericytes), CD36, and amyloid β colocalized in vitro and in vivo and that Aβ1-40 caused BBB destruction by upregulating the expression of CD36 in pericytes. The mechanism by which Aβ1-40 destroys the BBB involves induction of pericyte mitophagy-dependent ferroptosis through the CD36/PINK1/Parkin pathway.

scholarly journals Pseudogene ACTBP2 increases blood–brain barrier permeability by promoting KHDRBS2 transcription through recruitment of KMT2D/WDR5 in Aβ1–42 microenvironment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Qianshuo Liu ◽  
Xiaobai Liu ◽  
Defeng Zhao ◽  
Xuelei Ruan ◽  
Rui Su ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Vital Role ◽  
Brain Barrier ◽  
Blood Brain ◽  
Bbb Permeability ◽  
Novel Target ◽  
And Function

AbstractThe blood–brain barrier (BBB) has a vital role in maintaining the homeostasis of the central nervous system (CNS). Changes in the structure and function of BBB can accelerate Alzheimer’s disease (AD) development. β-Amyloid (Aβ) deposition is the major pathological event of AD. We elucidated the function and possible molecular mechanisms of the effect of pseudogene ACTBP2 on the permeability of BBB in Aβ1–42 microenvironment. BBB model treated with Aβ1–42 for 48 h were used to simulate Aβ-mediated BBB dysfunction in AD. We proved that pseudogene ACTBP2, RNA-binding protein KHDRBS2, and transcription factor HEY2 are highly expressed in ECs that were obtained in a BBB model in vitro in Aβ1–42 microenvironment. In Aβ1–42-incubated ECs, ACTBP2 recruits methyltransferases KMT2D and WDR5, binds to KHDRBS2 promoter, and promotes KHDRBS2 transcription. The interaction of KHDRBS2 with the 3′UTR of HEY2 mRNA increases the stability of HEY2 and promotes its expression. HEY2 increases BBB permeability in Aβ1–42 microenvironment by transcriptionally inhibiting the expression of ZO-1, occludin, and claudin-5. We confirmed that knocking down of Khdrbs2 or Hey2 increased the expression levels of ZO-1, occludin, and claudin-5 in APP/PS1 mice brain microvessels. ACTBP2/KHDRBS2/HEY2 axis has a crucial role in the regulation of BBB permeability in Aβ1–42 microenvironment, which may provide a novel target for the therapy of AD.

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