scholarly journals PKC-β Exacerbates in vitro Brain Barrier Damage in Hyperglycemic Settings via Regulation of RhoA/Rho-kinase/MLC2 Pathway

2013 ◽  
Vol 33 (12) ◽  
pp. 1928-1936 ◽  
Author(s):  
Kirtiman Srivastava ◽  
Beili Shao ◽  
Ulvi Bayraktutan
Keyword(s):  
Rho Kinase ◽  
Brain Barrier ◽  
Barrier Dysfunction ◽  
Glucose Levels ◽  
Kinase C ◽  
Junction Protein ◽  
Pkc Β ◽  
Vitro Model ◽  
And Function

Stroke patients with hyperglycemia (HG) develop higher volumes of brain edema emerging from disruption of blood–brain barrier (BBB). This study explored whether inductions of protein kinase C- β (PKC- β) and RhoA/Rho-kinase/myosin-regulatory light chain-2 (MLC2) pathway may account for HG-induced barrier damage using an in vitro model of human BBB comprising human brain microvascular endothelial cells (HBMEC) and astrocytes. Hyperglycemia (25 mmol/L D-glucose) markedly increased RhoA/Rho-kinase protein expressions (in-cell westerns), MLC2 phosphorylation (immunoblotting), and PKC- β (PepTag assay) and RhoA (Rhotekin-binding assay) activities in HBMEC while concurrently reducing the expression of tight junction protein occludin. Hyperglycemia-evoked in vitro barrier dysfunction, confirmed by decreases in transendothelial electrical resistance and concomitant increases in paracellular flux of Evan's blue-labeled albumin, was accompanied by malformations of actin cytoskeleton and tight junctions. Suppression of RhoA and Rho-kinase activities by anti-RhoA immunoglobulin G (IgG) electroporation and Y-27632, respectively prevented morphologic changes and restored plasma membrane localization of occludin. Normalization of glucose levels and silencing PKC- β activity neutralized the effects of HG on occludin and RhoA/Rho-kinase/MLC2 expression, localization, and activity and consequently improved in vitro barrier integrity and function. These results suggest that HG-induced exacerbation of the BBB breakdown after an ischemic stroke is mediated in large part by activation of PKC- β.

scholarly journals Blood–Brain Barrier Dysfunction in a 3D In Vitro Model of Alzheimer's Disease

2019 ◽  
Vol 6 (20) ◽  
pp. 1900962 ◽  
Author(s):  
Yoojin Shin ◽  
Se Hoon Choi ◽  
Eunhee Kim ◽  
Enjana Bylykbashi ◽  
Jeong Ah Kim ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Blood Brain Barrier ◽  
In Vitro Model ◽  
Brain Barrier ◽  
Barrier Dysfunction ◽  
Blood Brain ◽  
Model Of Alzheimer’S Disease ◽  
3D In Vitro Model ◽  
Vitro Model

scholarly journals Development of Physiologically Responsive Human iPSC-Derived Intestinal Epithelium to Study Barrier Dysfunction in IBD

2020 ◽  
Vol 21 (4) ◽  
pp. 1438 ◽  
Author(s):  
John P. Gleeson ◽  
Hannah Q. Estrada ◽  
Michifumi Yamashita ◽  
Clive N. Svendsen ◽  
Stephan R. Targan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Intestinal Permeability ◽  
Intestinal Epithelium ◽  
Adherens Junction ◽  
Induced Pluripotent Stem Cell ◽  
Barrier Dysfunction ◽  
Junction Protein ◽  
Vitro Model ◽  
Induced Pluripotent

In inflammatory bowel disease (IBD), the intestinal epithelium is characterized by increased permeability both in active disease and remission states. The genetic underpinnings of this increased intestinal permeability are largely unstudied, in part due to a lack of appropriate modelling systems. Our aim is to develop an in vitro model of intestinal permeability using induced pluripotent stem cell (iPSC)-derived human intestinal organoids (HIOs) and human colonic organoids (HCOs) to study barrier dysfunction. iPSCs were generated from healthy controls, adult onset IBD, and very early onset IBD (VEO-IBD) patients and differentiated into HIOs and HCOs. EpCAM+ selected cells were seeded onto Transwell inserts and barrier integrity studies were carried out in the presence or absence of pro-inflammatory cytokines TNFα and IFNγ. Quantitative real-time PCR (qRT-PCR), transmission electron microscopy (TEM), and immunofluorescence were used to determine altered tight and adherens junction protein expression or localization. Differentiation to HCO indicated an increased gene expression of CDX2, CD147, and CA2, and increased basal transepithelial electrical resistance compared to HIO. Permeability studies were carried out in HIO- and HCO-derived epithelium, and permeability of FD4 was significantly increased when exposed to TNFα and IFNγ. TEM and immunofluorescence imaging indicated a mislocalization of E-cadherin and ZO-1 in TNFα and IFNγ challenged organoids with a corresponding decrease in mRNA expression. Comparisons between HIO- and HCO-epithelium show a difference in gene expression, electrophysiology, and morphology: both are responsive to TNFα and IFNγ stimulation resulting in enhanced permeability, and changes in tight and adherens junction architecture. This data indicate that iPSC-derived HIOs and HCOs constitute an appropriate physiologically responsive model to study barrier dysfunction and the role of the epithelium in IBD and VEO-IBD.

scholarly journals Therapeutic hypothermia augments the restorative effects of PKC-β and Nox2 inhibition on an in vitro model of human blood–brain barrier

2021 ◽  
Author(s):  
Rais Reskiawan A. Kadir ◽  
Mansour Alwjwaj ◽  
Zoe McCarthy ◽  
Ulvi Bayraktutan
Keyword(s):  
Therapeutic Hypothermia ◽  
Human Blood ◽  
Superoxide Anion ◽  
In Vitro Model ◽  
Superoxide Anion Production ◽  
Anion Production ◽  
Pkc Β ◽  
Vitro Model ◽  
And Function

AbstractTo investigate whether therapeutic hypothermia augments the restorative impact of protein kinase C-β (PKC-β) and Nox2 inhibition on an in vitro model of human blood–brain barrier (BBB). Cells cultured in normoglycaemic (5.5 mM) or hyperglycaemic (25 mM, 6 to 120 h) conditions were treated with therapeutic hypothermia (35 °C) in the absence or presence of a PKC-β inhibitor (LY333531, 0.05 μM) or a Nox2 inhibitor (gp91ds-tat, 50 μM). BBB was established by co-culture of human brain microvascular endothelial cells (HBMECs) with astrocytes (HAs) and pericytes. BBB integrity and function were assessed via transendothelial electrical resistance (TEER) and paracellular flux of sodium fluorescein (NaF, 376 Da). Nox activity (lucigenin assay), superoxide anion production (cytochrome-C reduction assay), cellular proliferative capacity (wound scratch assay) and actin cytoskeletal formation (rhodamine-phalloidin staining) were assessed both in HBMECs and HAs using the specific methodologies indicated in brackets. Therapeutic hypothermia augmented the protective effects of PKC-β or Nox2 inhibition on BBB integrity and function in experimental setting of hyperglycaemia, as evidenced by increases in TEER and concomitant decreases in paracellular flux of NaF. The combinatory approaches were more effective in repairing physical damage exerted on HBMEC and HA monolayers by wound scratch and in decreasing Nox activity and superoxide anion production compared to sole treatment regimen with either agent. Similarly, the combinatory approaches were more effective in suppressing actin stress fibre formation and maintaining normal cytoskeletal structure. Therapeutic hypothermia augments the cerebral barrier-restorative capacity of agents specifically targeting PKC-β or Nox2 pathways.

Glucocorticoids regulate barrier function and claudin expression in intestinal epithelial cells via MKP-1

2014 ◽  
Vol 306 (3) ◽  
pp. G218-G228 ◽  
Author(s):  
Andreas Fischer ◽  
Markus Gluth ◽  
Friderike Weege ◽  
Ulrich-Frank Pape ◽  
Bertram Wiedenmann ◽  
...  
Keyword(s):  
Tight Junction ◽  
Barrier Function ◽  
Collagenous Colitis ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Barrier Dysfunction ◽  
Junction Protein ◽  
Bowel Diseases ◽  
Vitro Model

Barrier dysfunction is pivotal to the pathogenesis of inflammatory bowel diseases (IBD) and collagenous colitis. Glucocorticoids restore barrier function in Crohn's disease, but whether this reflects attenuated inflammation or an epithelial-specific action has not yet been addressed. Using filter-grown Caco-2 monolayers as an in vitro model of the intestinal epithelial barrier, we observed that glucocorticoids induced a time- and dose-dependent increase in transepithelial electrical resistance (TEER) in a glucocorticoid receptor-dependent manner without altering flux of larger solutes or changing principal tight junction architecture. This was accompanied by reduced paracellular cation flux, reduced expression of the pore-forming tight junction component claudin-2, and upregulation of the sealing tight junction protein claudin-4. In contrast, expression of occludin, claudin-1, -7, or -8 was not altered. Dexamethasone increased expression and activity of MAPK phosphatase-1 and inhibition of this phosphatase prevented the glucocorticoid-induced changes in TEER and claudin expression, whereas inhibiting p38 or MEK1/2 was not sufficient to replicate the glucocorticoid effects. Upon exposure to IFN-γ, TNF-α, or IL-1β, TEERs declined in dexamethasone-treated cells but remained consistently higher than in cells not receiving glucocorticoids. Treatment with IFN/TNF resulted in an upregulation of claudin-2 that was significantly attenuated by dexamethasone, whereas increased claudin-2 expression upon IL-1β stimulation was not affected by glucocorticoids. Taken together, barrier augmentation might represent a previously unrecognized mechanism of action, potentially contributing to the therapeutic efficacy of glucocorticoids in IBD and collagenous colitis.

Role of thrombin-PAR1-PKCθ/δ axis in brain pericytes in thrombin-induced MMP-9 production and blood–brain barrier dysfunction in vitro

Neuroscience ◽  
2017 ◽  
Vol 350 ◽  
pp. 146-157 ◽  
Author(s):  
Takashi Machida ◽  
Shinya Dohgu ◽  
Fuyuko Takata ◽  
Junichi Matsumoto ◽  
Ikuya Kimura ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Barrier Dysfunction ◽  
Blood Brain ◽  
Brain Pericytes

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.

Mesothelial Cells

2007 ◽  
Vol 27 (2_suppl) ◽  
pp. 110-115 ◽  
Author(s):  
Susan Yung ◽  
Chan Tak Mao
Keyword(s):  
Mesothelial Cell ◽  
In Vitro Models ◽  
Mesothelial Cells ◽  
Dynamic Membrane ◽  
Peritoneal Mesothelial Cells ◽  
Immunohistochemical Markers ◽  
Vitro Model ◽  
And Function

♦ Background The introduction of peritoneal dialysis (PD) as a modality of renal replacement therapy has provoked much interest in the biology of the peritoneal mesothelial cell. Mesothelial cells isolated from omental tissue have immunohistochemical markers that are identical to those of mesothelial stem cells, and omental mesothelial cells can be cultivated in vitro to study changes to their biologic functions in the setting of PD. ♦ Method The present article describes the structure and function of mesothelial cells in the normal peritoneum and details the morphologic changes that occur after the introduction of PD. Furthermore, this article reviews the literature of mesothelial cell culture and the limitations of in vitro studies. ♦ Results The mesothelium is now considered to be a dynamic membrane that plays a pivotal role in the homeostasis of the peritoneal cavity, contributing to the control of fluid and solute transport, inflammation, and wound healing. These functional properties of the mesothelium are compromised in the setting of PD. Cultures of peritoneal mesothelial cells from omental tissue provide a relevant in vitro model that allows researchers to assess specific molecular pathways of disease in a distinct population of cells. Structural and functional attributes of mesothelial cells are discussed in relation to long-term culture, proliferation potential, age of tissue donor, use of human or animal in vitro models, and how the foregoing factors may influence in vitro data. ♦ Conclusions The ability to propagate mesothelial cells in culture has resulted, over the past two decades, in an explosion of mesothelial cell research pertaining to PD and peritoneal disorders. Independent researchers have highlighted the potential use of mesothelial cells as targets for gene therapy or transplantation in the search to provide therapeutic strategies for the preservation of the mesothelium during chemical or bacterial injury.

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