Expression of junctional proteins in choroid plexus epithelial cell lines: a comparative study

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Amyloid-beta transporter expression at the blood-CSF barrier is age-dependent

<p>Abstract</p> <p>Background</p> <p>Age is the major risk factor for many neurodegenerative diseases, including Alzheimer's disease (AD). There is an accumulation of amyloid-beta peptides (Aβ) in both the AD brain and the normal aging brain. Clearance of Aβ from the brain occurs via active transport at the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). With increasing age, the expression of the Aβ efflux transporters is decreased and the Aβ influx transporter expression is increased at the BBB, adding to the amyloid burden in the brain. Expression of the Aβ transporters at the choroid plexus (CP) epithelium as a function of aging was the subject of this study.</p> <p>Methods</p> <p>This project investigated the changes in expression of the Aβ transporters, the low density lipoprotein receptor-related protein-1 (LRP-1), P-glycoprotein (P-gp), LRP-2 (megalin) and the receptor for advanced glycation end-products (RAGE) at the BCSFB in Brown-Norway/Fischer rats at ages 3, 6, 9, 12, 20, 30 and 36 months, using real time RT-PCR to measure transporter mRNA expression, and immunohistochemistry (IHC) to measure transporter protein in isolated rat CP.</p> <p>Results</p> <p>There was an increase in the transcription of the Aβ efflux transporters, LRP-1 and P-gp, no change in RAGE expression and a decrease in LRP-2, the CP epithelium influx transporter, at the BCSFB with aging. Decreased Aβ42 concentration in the CP, as measured by quantitative IHC, was associated with these Aβ transporter alterations.</p> <p>Conclusions</p> <p>Age-dependent alterations in the CP Aβ transporters are associated with a decrease in Aβ42 accumulation in the CP, and are reciprocal to the changes seen in these transporters at the BBB, suggesting a possible compensatory role for the BCSFB in Aβ clearance in aging.</p

Cigarette Smoke Initiates Oxidative Stress-Induced Cellular Phenotypic Modulation Leading to Cerebral Aneurysm Pathogenesis.

OBJECTIVE: Cigarette smoke exposure (CSE) is a risk factor for cerebral aneurysm (CA) formation, but the molecular mechanisms are unclear. Although CSE is known to contribute to excess reactive oxygen species generation, the role of oxidative stress on vascular smooth muscle cell (VSMC) phenotypic modulation and pathogenesis of CAs is unknown. The goal of this study was to investigate whether CSE activates a NOX (NADPH oxidase)-dependent pathway leading to VSMC phenotypic modulation and CA formation and rupture. APPROACH AND RESULTS: In cultured cerebral VSMCs, CSE increased expression of NOX1 and reactive oxygen species which preceded upregulation of proinflammatory/matrix remodeling genes (MCP-1, MMPs [matrix metalloproteinase], TNF-α, IL-1β, NF-κB, KLF4 [Kruppel-like factor 4]) and downregulation of contractile genes (SM-α-actin [smooth muscle α actin], SM-22α [smooth muscle 22α], SM-MHC [smooth muscle myosin heavy chain]) and myocardin. Inhibition of reactive oxygen species production and knockdown of NOX1 with siRNA or antisense decreased CSE-induced upregulation of NOX1 and inflammatory genes and downregulation of VSMC contractile genes and myocardin. p47phox-/- NOX knockout mice, or pretreatment with the NOX inhibitor, apocynin, significantly decreased CA formation and rupture compared with controls. NOX1 protein and mRNA expression were similar in p47phox-/- mice and those pretreated with apocynin but were elevated in unruptured and ruptured CAs. CSE increased CA formation and rupture, which was diminished with apocynin pretreatment. Similarly, NOX1 protein and mRNA and reactive oxygen species were elevated by CSE, and in unruptured and ruptured CAs. CONCLUSIONS: CSE initiates oxidative stress-induced phenotypic modulation of VSMCs and CA formation and rupture. These molecular changes implicate oxidative stress in the pathogenesis of CAs and may provide a potential target for future therapeutic strategies

Western blot analysis of expression of junctional proteins in CP cell lines

<p><b>Copyright information:</b></p><p>Taken from "Expression of junctional proteins in choroid plexus epithelial cell lines: a comparative study"</p><p>http://www.cerebrospinalfluidresearch.com/content/4/1/11</p><p>Cerebrospinal Fluid Research 2007;4():11-11.</p><p>Published online 27 Dec 2007</p><p>PMCID:PMC2241822.</p><p></p> A, B, and C. Expression of TJ proteins, claudin 1, claudin 2, and occludin. D. Expression of AJ protein, E-cadherin. Z310 and TR-CSFB3 cell lines were derived from rat CP epithelium, whereas the CPC-2 cell line was derived from human CP carcinoma. The amount of protein loaded is shown for each lane. rCP and hCP are rat and human CP tissues used as a positive control

Cigarette Smoke Initiates Oxidative Stress-Induced Phenotypic Modulation of Vascular Smooth Muscle Cells Leading to Cerebral Aneurysm Formation and Rupture

Abstract INTRODUCTION: To investigate the role of cigarette smoke exposure (CSE) in the regulation of cerebral smooth muscle cell (SMC) phenotypic modulation in a NAPDH (NOX)-dependent manner and its effect on cerebral aneurysm (CA) formation and rupture. METHODS: Cultured rat cerebral vascular SMCs and mice following cerebral aneurysm induction surgery underwent CSE during both in vitro and in vivo experiments. RESULTS: In cultured cerebral vascular SMCs, CSE increased expression of NOX-1 and reactive oxygen species (ROS) as early as 4 hours after treatment, with maximal upregulation of proinflammatory/matrix remodeling genes (MCP-1, MMPs, TNF-α, IL-1β, NF-κB, KLF4) at 24 hours. SMC contractile genes (SM-a-actin, SM-22a, SM-MHC) and myocardin were maximally decreased at 24 hours. Inhibition with superoxide dismutase and viral Ad/AS-NOX1 decreased CSE-induced upregulation of NOX-1 and inflammatory genes and downregulation of SMC contractile genes and myocardin. NOX p47phox−/− mice and those pretreated with apocynin had significantly decreased incidence of CA formation and rupture. Additionally, mice exposed to cigarette smoke had an increased incidence of CA formation and rupture, which was diminished with apocynin pretreatment. NOX-1 protein, mRNA, and ROS were elevated in animals exposed to cigarette smoke, and in unruptured and furthermore in ruptured CAs. CONCLUSION: CSE initiates oxidative stress-induced phenotypic modulation of SMCs leading to CA formation and rupture. These molecular changes implicate oxidative stress in the pathogenesis of CAs and may provide a potential target for future therapeutic strategies

Lymphocytes influence intracranial aneurysm formation and rupture: role of extracellular matrix remodeling and phenotypic modulation of vascular smooth muscle cells

BACKGROUND: Intracranial aneurysms (IA) are increasingly recognized as a disease driven by chronic inflammation. Recent research has identified key mediators and processes underlying IA pathogenesis, but mechanistic understanding remains incomplete. Lymphocytic infiltrates have been demonstrated in patient IA tissue specimens and have also been shown to play an important role in abdominal aortic aneurysms (AAA) and related diseases such as atherosclerosis. However, no study has systematically examined the contribution of lymphocytes in a model of IA. METHODS: Lymphocyte-deficient (Rag1) and wild-type (WT; C57BL/6 strain) mice were subjected to a robust IA induction protocol. Rates of IA formation and rupture were measured, and cerebral artery tissue was collected and utilized for histology and gene expression analysis. RESULTS: At 2 weeks, the Rag1 group had significantly fewer IA formations and ruptures than the WT group. Histological analysis of unruptured IA tissue showed robust B and T lymphocyte infiltration in the WT group, while there were no differences in macrophage infiltration, IA diameter, and wall thickness. Significant differences in interleukin-6 (IL-6), matrix metalloproteinases 2 (MMP2) and 9 (MMP9), and smooth muscle myosin heavy chain (MHC) were observed between the groups. CONCLUSIONS: Lymphocytes are key contributors to IA pathogenesis and provide a novel target for the prevention of IA progression and rupture in patients

Dimethyl Fumarate Mediates Sustained Vascular Smooth Muscle Cell Remodeling in a Mouse Model of Cerebral Aneurysm

Cerebral aneurysms (CA) are a type of vascular disease that causes significant morbidity and mortality with rupture. Dysfunction of the vascular smooth muscle cells (VSMCs) from circle of Willis (CoW) vessels mediates CA formation, as they are the major cell type of the arterial wall and play a role in maintaining vessel integrity. Dimethyl fumarate (DMF), a first-line oral treatment for relapsing-remitting multiple sclerosis, has been shown to inhibit VSMC proliferation and reduce CA formation in a mouse model. Potential unwanted side effects of DMF on VSMC function have not been investigated yet. The present study characterizes the impact of DMF on VSMC using single-cell RNA-sequencing (scRNA-seq) in CoW vessels following CA induction and further explores its role in mitochondrial function using in vitro VSMC cultures. Two weeks of DMF treatment following CA induction impaired the transcription of the glutathione redox system and downregulated mitochondrial respiration genes in VSMCs. In vitro, DMF treatment increased lactate formation and enhanced the mitochondrial production of reactive oxygen species (ROS). These effects rendered VSMCs vulnerable to oxidative stress and led to mitochondrial dysfunction and enhancement of apoptosis. Taken together, our data support the concept that the DMF-mediated antiproliferative effect on VSMCs is linked to disturbed antioxidative functions resulting in altered mitochondrial metabolism. This negative impact of DMF treatment on VSMCs may be linked to preexisting alterations of cerebrovascular function due to renal hypertension. Therefore, before severe adverse effects emerge, it would be clinically relevant to develop indices or biomarkers linked to this disturbed antioxidative function to monitor patients undergoing DMF treatment