Imaging of Fibroblast Activation Protein Alpha Expression in a Preclinical Mouse Model of Glioma Using Positron Emission Tomography.

Glioblastoma multiforme (GBM) is the most aggressive glioma of the primary central nervous system. Due to the lack of effective treatment options, the prognosis for patients remains bleak. Fibroblast activation protein alpha (FAP), a 170 kDa type II transmembrane serine protease was observed to be expressed on glioma cells and within the glioma tumor microenvironment.

Dysregulated Pyrimidine Biosynthesis Contributes to 5-FU Resistance in SCLC Patient-Derived Organoids but Response to a Novel Polymeric Fluoropyrimidine, CF10.

Chemo-immunotherapy is central to the treatment of small cell lung cancer (SCLC). Despite modest progress made with the addition of immunotherapy, current cytotoxic regimens display minimal survival benefit and new treatments are needed. Thymidylate synthase (TS) is a well-validated anti-cancer drug target, but conventional TS inhibitors display limited clinical efficacy in refractory or recurrent SCLC.

Tumor-associated stromal cells as key contributors to the tumor microenvironment.

The tumor microenvironment is a heterogeneous population of cells consisting of the tumor bulk plus supporting cells. It is becoming increasingly evident that these supporting cells are recruited by cancer cells from nearby endogenous host stroma and promote events such as tumor angiogenesis, proliferation, invasion, and metastasis, as well as mediate mechanisms of therapeutic resistance. In addition, recruited stromal cells range in type and include vascular endothelial cells, pericytes, adipocytes, fibroblasts, and bone-marrow mesenchymal stromal cells.

Effects of nanoparticles on the adhesion and cell viability on astrocytes.

In recent years, both pharmaceutical companies and manufacturing industries have expressed heightened interest in the potential applications of magnetic nanoparticles for therapeutic and technological purposes. Specifically, pharmaceutical companies seek to employ magnetic nanoparticles as carriers to facilitate effective drug delivery, especially in areas of the brain. Manufacturing industries desire to use these nanoparticles as ferrofluids and in magnetic resonance imaging.

Mercuric chloride inhibits the in vitro uptake of glutamate in GLAST- and GLT-1-transfected mutant CHO-K1 cells.

Glutamate is removed mainly by astrocytes from the extracellular fluid via high-affinity astroglial Na+ -dependent excitatory amino acid transporters, glutamate/aspartate transporter (GLAST), and glutamate transporter-1 (GLT-1). Mercuric chloride (HgCl2) is a highly toxic compound that inhibits glutamate uptake in astrocytes, resulting in excessive extracellular glutamate accumulation, leading to excitotoxicity and neuronal cell death. The mechanisms associated with the inhibitory effects of HgCl2 on glutamate uptake are unknown.

Methylmercury alters the in vitro uptake of glutamate in GLAST- and GLT-1-transfected mutant CHO-K1 cells.

In order to maintain normal functioning of the brain, glutamate homeostasis and extracellular levels of excitotoxic amino acids (EAA) must be tightly controlled. This is accomplished, in large measure, by the astroglial high-affinity Na+-dependent EAA transporters glutamate/ aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1). Methylmercury (MeHg) is a potent neurotoxicant.

The in vitro uptake of glutamate in GLAST and GLT-1 transfected mutant CHO-K1 cells is inhibited by manganese.

In the central nervous system (CNS), extracellular concentrations of amino acids (e.g., aspartate, glutamate) and divalent metals (e.

Acrylamide stimulates glutamine uptake in Fischer 344 rat astrocytes by a mechanism involving upregulation of the amino acid transport system N.

High demand of neoplastic tissues for glutamine (Gln) is met by its active transport across cell membranes. Chronic treatment with acrylamide in rodents is associated with an increased incidence of neoplasms, including astrocytomas. In this study, 24-h acrylamide treatment significantly increased the initial rate of l-[G-3H]glutamine uptake in astrocyte cultures derived from the acrylamide-sensitive Fischer 344 rat, and this effect could be fully inhibited by histidine, a model substrate for the amino acid transport system N.

In vitro uptake of glutamate in GLAST- and GLT-1-transfected mutant CHO-K1 cells is inhibited by the ethylmercury-containing preservative thimerosal.

Thimerosal, also known as thimersal, Merthrolate, or sodiumethyl-mercurithiosalicylate, is an organic mercurial compound that is used in a variety of commercial as well as biomedical applications. As a preservative, it is used in a number of vaccines and pharmaceutical products. Its active ingredient is ethylmercury.

Chronic ethanol produces increased taurine transport and efflux in cultured astrocytes.

Due to ethanol's low potency and low level of toxicity, high amounts of ethanol are consumed to achieve pharmacological effects. Blood levels of ethanol in chronic alcoholics may reach as high as 80-100 mM. We undertook a series of studies to determine if these high levels of ethanol stimulated osmoregulatory processes in cultured astrocytes.

CARD15 mutations in familial granulomatosis syndromes: a study of the original Blau syndrome kindred and other families with large-vessel arteritis and cranial neuropathy.

Objective: To analyze the CARD15 gene in families with heritable multi-organ granulomatoses, including the original Blau syndrome kindred as well as other families with related granulomatous conditions.

Methods: Linkage mapping was performed in 10 families. Observed recombination events were used to exclude regions centromeric or telomeric to 16q12.

Methylmercury enhances arachidonic acid release and cytosolic phospholipase A2 expression in primary cultures of neonatal astrocytes.

Cytosolic phospholipase A(2) (cPLA(2)) stimulates the hydrolysis of sn-2 ester bond in membrane phospholipids releasing arachidonic acid (AA) and lysophospholipids. The present study examined the effect of methylmercury (MeHg) on cPLA(2) activation and AA release in primary cultures of neonatal rat cerebral astrocytes. Astrocytes were preloaded overnight at 37 degrees C with 3H-AA to metabolically label phospholipids.

The uptake of manganese in brain endothelial cultures.

The present study focused on central nervous system (CNS) transport kinetics of manganese phosphate and manganese sulfate; these findings were correlated with the transport kinetics of manganese chloride (MnCl2), a model Mn compound that has been previously studied. A series of studies was performed to address the transport of Mn salts in confluent cultured endothelial cells. The initial rate of uptake (5 min) of Mn salts (chloride, sulfate, and phosphate) in rat brain endothelial (RBE4) cell cultures is salt-dependent, with the highest rates of uptake for Mn chloride and Mn sulfate (as reflected by the greatest displacement of 54Mn compared with control).

Aspartate and glutamate transport in acutely and chronically ethanol exposed neonatal rat primary astrocyte cultures.

Maintenance of the ionic and osmotic composition of the extracellular fluid (ECF) is essential for the optimal functioning of the central nervous system (CNS). Changes in ion and neurotransmitter levels in the cerebrospinal fluid (CSF) can have profound effects on the processing and transmission of neuronal signals. Cell swelling during correction of isotonic imbalances can produce a series of events leading to inappropriate release of excitatory amino acids (EAA).

Transendothelial permeability of chlorpyrifos in RBE4 monolayers is modulated by astrocyte-conditioned medium.

The immortalized rat brain endothelium 4 (RBE4) cell line preserves many features of the in vivo brain endothelium. It has been used as an in vitro model of the blood-brain barrier (BBB). Astrocyte-endothelial cell interactions are crucial for maintenance of BBB characteristics.

Methylmercury inhibits cysteine uptake in cultured primary astrocytes, but not in neurons.

The maintenance of adequate intracellular glutathione (GSH) concentrations is dependent on the availability and transport of the rate-limiting substrate, cysteine. A suggested mechanism of methylmercury (MeHg) neurotoxicity in brain involves the formation of oxygen radicals, and a decrease in intracellular levels of GSH. Recently, we have characterized various cysteine transport systems (both Na(+)-dependent and -independent) in cerebrocortical astrocytes and hippocampal neurons.

The uptake of cysteine in cultured primary astrocytes and neurons.

One of the vitally important functions of glutathione (GSH) is to adequately protect cells against toxic chemicals, reactive oxygen metabolites and free radical species. The amino acid, cysteine, is the key rate-limiting substrate for the biosynthesis of GSH, and the maintenance of adequate intracellular GSH levels is dependent upon the extracellular availability and transport of cysteine into cells. In the present study, primary cultures of astrocytes and neurons were employed to characterize cysteine transport systems.

Methylmercury-mediated inhibition of 3H-D-aspartate transport in cultured astrocytes is reversed by the antioxidant catalase.

Astrocytes are essential for removal of glutamate from the extracellular space in the central nervous system. The neurotoxic heavy metal methylmercury potently and specifically inhibits the transport of glutamate in cultured astrocytes by an unknown mechanism. Glutamate transport in astrocytes is also inhibited by reactive oxygen species.

Ethanol-induced swelling in neonatal rat primary astrocyte cultures.

We tested the hypothesis that astrocytes swell in response to ethanol (EtOH) exposure. The experimental approach consisted of an electrical impedance method designed to measure cell volume. In chronic experiments, EtOH (100 mM) was added to the culture media for 1, 3, or 7 days.

Isolation of neonatal rat cortical astrocytes for primary cultures.

There is increasing interest in the role of astrocytes as mediators of neurotoxicity. This unit describes a method for preparing astrocyte cultures of greater than 95% purity by enzymatic dissociation from neonatal rat brain. These preparations have both high yield and high viability.

Mercuric chloride, but not methylmercury, inhibits glutamine synthetase activity in primary cultures of cortical astrocytes.

Methylmercury (MeHg) is highly neurotoxic with an apparent dose-related latency period between time of exposure and the appearance of symptoms. Astrocytes are known targets for MeHg toxicity and a site of mercury localization within the central nervous system (CNS). Glutamine synthetase (GS) is an enzyme localized predominately within astrocytes.

Foreign metallothionein-I expression by transient transfection in MT-I and MT-II null astrocytes confers increased protection against acute methylmercury cytotoxicity.

The mechanisms associated with metallothionein (MT) gene regulation are complex and poorly understood. Only a modest increase in brain MT expression levels is attained by exposure to metals, MT gene transfection, and MT gene knock-in techniques. Accordingly, in the present study, MT null astrocytes isolated from transgenic mice deficient in MT-I and MT-II genes were introduced as a zero background model of MT expression.