Attenuation of prostaglandin E2 elimination across the mouse blood-brain barrier in lipopolysaccharide-induced inflammation and additive inhibitory effect of cefmetazole

<p>Abstract</p> <p>Background</p> <p>Peripheral administration of lipopolysaccharide (LPS) induces inflammation and increases cerebral prostaglandin E₂(PGE₂) concentration. PGE₂is eliminated from brain across the blood-brain barrier (BBB) in mice, and this process is inhibited by intracerebral or intravenous pre-administration of anti-inflammatory drugs and antibiotics such as cefmetazole and cefazolin that inhibit multidrug resistance-associated protein 4 (Mrp4/Abcc4)-mediated PGE₂transport. The purpose of this study was to examine the effect of LPS-induced inflammation on PGE₂elimination from brain, and whether antibiotics further inhibit PGE₂elimination in LPS-treated mice.</p> <p>Methods</p> <p>[³H]PGE₂elimination across the BBB of intraperitoneally LPS-treated mice was assessed by the brain efflux index (BEI) method. Transporter protein amounts in brain capillaries were quantified by liquid chromatography-tandem mass spectrometry.</p> <p>Results</p> <p>The apparent elimination rate of [³H]PGE₂from brain was lower by 87%, in LPS-treated mice compared with saline-treated mice. The Mrp4 protein amount was unchanged in brain capillaries of LPS-treated mice compared with saline-treated mice, while the protein amounts of organic anion transporter 3 (Oat3/Slc22a8) and organic anion transporting polypeptide 1a4 (Oatp1a4/Slco1a4) were decreased by 26% and 39%, respectively. Either intracerebral or intravenous pre-administration of cefmetazole further inhibited PGE₂elimination in LPS-treated mice. However, intracerebral or intravenous pre-administration of cefazolin had little effect on PGE₂elimination in LPS-treated mice, or in LPS-untreated mice given Oat3 and Oatp1a4 inhibitors. These results indicate that peripheral administration of cefmetazole inhibits PGE₂elimination across the BBB in LPS-treated mice.</p> <p>Conclusion</p> <p>PGE₂elimination across the BBB is attenuated in an LPS-induced mouse model of inflammation. Peripheral administration of cefmetazole further inhibits PGE₂elimination in LPS-treated mice.</p

Crystal Spectroscopy for Kα X-rays from Silicon Bombarded with Protons and Alpha Particles

An automated Bragg spectrometer in which an organic electron multiplier is employed as an X-ray detector has been designed, and the Kₐ diagram and satellite X-rays from silicon bombarded with hydrogen and helium ions at MeV energies have been analyzed. The procedures of deriving the ionization cross sections from the satellite intensities are described. The multiple KL" ionization cross sections are compared with the theoretical binomial distribution, which means a statistical superposition of single ionizations

Impact of Cationic Amino Acid Transporter 1 on Blood- Retinal Barrier Transport of L-Ornithine

PURPOSE. To elucidate L-ornithine transport at the blood-retinal barrier (BRB). METHODS. Integration plot and retinal uptake index (RUI) were used to investigate the in vivo [ 3 H]L-ornithine transport across the BRB. In vitro transport studies of [ 3 H]L-ornithine were performed with TR-iBRB2 cells and RPE-J cells, the model cells of the inner and outer BRB, respectively. Immunohistochemistry was performed on cationic amino acid transporter 1 (CAT1/SLC7A1). RESULTS. The apparent influx permeability clearance of [ 3 H]L-ornithine was found to be 18. 7 lL/(minÁg retina), and the RUI of [ 3 H]L-ornithine was reduced by L-ornithine and L-arginine, suggesting the blood-to-retina transport of L-ornithine at the BRB. [ 3 H]L-Ornithine uptake by TR-iBRB2 cells showed a time-, temperature-and concentration-dependence with a MichaelisMenten constant (K m ) of 33.2 lM and a nonsaturable uptake rate (K d ) of 2.18 lL/(minÁmg protein). The uptake was Na þ -independent, and was inhibited by L-ornithine, L-arginine, and L-lysine, suggesting the involvement of CAT1 in L-ornithine transport at the inner BRB. Immunohistochemistry revealed the luminal and abluminal localization of CAT1 at the inner BRB, and at the basal localization at the outer BRB. Retinal pigment epithelium-J cells showed that the basal-to-cell (B-to-C) uptake of [ 3 H]L-ornithine was greater than that of the apical-tocell (A-to-C) uptake, and the B-to-C transport was inhibited by unlabeled L-ornithine, suggesting the involvement of CAT1 in the blood-to-cell transport of L-ornithine across the basal membrane at the outer BRB. CONCLUSIONS. These suggest the involvement of CAT1 in L-ornithine transport at the luminal and abluminal sides of the inner BRB and the basal side of the outer BRB

Birth of Archaeal Cells: Molecular Phylogenetic Analyses of G1P Dehydrogenase, G3P Dehydrogenases, and Glycerol Kinase Suggest Derived Features of Archaeal Membranes Having G1P Polar Lipids

Bacteria and Eukarya have cell membranes with sn-glycerol-3-phosphate (G3P), whereas archaeal membranes contain sn-glycerol-1-phosphate (G1P). Determining the time at which cells with either G3P-lipid membranes or G1P-lipid membranes appeared is important for understanding the early evolution of terrestrial life. To clarify this issue, we reconstructed molecular phylogenetic trees of G1PDH (G1P dehydrogenase; EgsA/AraM) which is responsible for G1P synthesis and G3PDHs (G3P dehydrogenase; GpsA and GlpA/GlpD) and glycerol kinase (GlpK) which is responsible for G3P synthesis. Together with the distribution of these protein-encoding genes among archaeal and bacterial groups, our phylogenetic analyses suggested that GlpA/GlpD in the Commonote (the last universal common ancestor of all extant life with a cellular form, Commonote commonote) acquired EgsA (G1PDH) from the archaeal common ancestor (Commonote archaea) and acquired GpsA and GlpK from a bacterial common ancestor (Commonote bacteria). In our scenario based on this study, the Commonote probably possessed a G3P-lipid membrane synthesized enzymatically, after which the archaeal lineage acquired G1PDH followed by the replacement of a G3P-lipid membrane with a G1P-lipid membrane

Total Synthesis of Decahydroquinoline Poison Frog Alkaloids ent-cis-195A and cis-211A

The total synthesis of two decahydroquinoline poison frog alkaloids ent-cis-195A and cis-211A were achieved in 16 steps (38% overall yield) and 19 steps (31% overall yield), respectively, starting from known compound 1. Both alkaloids were synthesized from the common key intermediate 11 in a divergent fashion, and the absolute stereochemistry of natural cis-211A was determined to be 2R, 4aR, 5R, 6S, and 8aS. Interestingly, the absolute configuration of the parent decahydroquinoline nuclei of cis-211A was the mirror image of that of cis-195A, although both alkaloids were isolated from the same poison frog species, Oophaga (Dendrobates) pumilio, from Panama

Total Synthesis of Decahydroquinoline Poison Frog Alkaloids ent-\u3ci\u3ecis\u3c/i\u3e-195A and \u3ci\u3ecis\u3c/i\u3e-211A

The total synthesis of two decahydroquinoline poison frog alkaloids ent-cis-195A and cis-211A were achieved in 16 steps (38% overall yield) and 19 steps (31% overall yield), respectively, starting from known compound 1. Both alkaloids were synthesized from the common key intermediate 11 in a divergent fashion, and the absolute stereochemistry of natural cis-211A was determined to be 2R, 4aR, 5R, 6S, and 8aS. Interestingly, the absolute configuration of the parent decahydroquinoline nuclei of cis-211A was the mirror image of that of cis-195A, although both alkaloids were isolated from the same poison frog species, Oophaga (Dendrobates) pumilio, from Panama

γ-Aminobutyric Acid Transporter 2 Mediates the Hepatic Uptake of Guanidinoacetate, the Creatine Biosynthetic Precursor, in Rats

Guanidinoacetic acid (GAA) is the biosynthetic precursor of creatine which is involved in storage and transmission of phosphate-bound energy. Hepatocytes readily convert GAA to creatine, raising the possibility that the active uptake of GAA by hepatocytes is a regulatory factor. The purpose of this study is to investigate and identify the transporter responsible for GAA uptake by hepatocytes. The characteristics of [14C]GAA uptake by hepatocytes were elucidated using the in vivo liver uptake method, freshly isolated rat hepatocytes, an expression system of Xenopus laevis oocytes, gene knockdown, and an immunohistochemical technique. In vivo injection of [14C]GAA into the rat femoral vein and portal vein results in the rapid uptake of [14C]GAA by the liver. The uptake was markedly inhibited by γ-aminobutyric acid (GABA) and nipecotinic acid, an inhibitor of GABA transporters (GATs). The characteristics of Na+- and Cl−-dependent [14C]GAA uptake by freshly isolated rat hepatocytes were consistent with those of GAT2. The Km value of the GAA uptake (134 µM) was close to that of GAT2-mediated GAA transport (78.9 µM). GABA caused a marked inhibition with an IC50 value of 8.81 µM. The [14C]GAA uptake exhibited a significant reduction corresponding to the reduction in GAT2 protein expression. GAT2 was localized on the sinusoidal membrane of the hepatocytes predominantly in the periportal region. This distribution pattern was consistent with that of the creatine biosynthetic enzyme, S-adenosylmethionine∶guanidinoacetate N-methyltransferase. GAT2 makes a major contribution to the sinusoidal GAA uptake by periportal hepatocytes, thus regulating creatine biosynthesis in the liver

Role of cationic drug-sensitive transport systems at the blood-cerebrospinal fluid barrier in para-tyramine elimination from rat brain

Abstract Background para-Tyramine (p-TA) is a biogenic amine which is involved in multiple neuronal signal transductions. Since the concentration of p-TA in dog cerebrospinal fluid (CSF) has been reported to be greater than that in plasma, it is proposed that clearance of cerebral p-TA is important for normal function. The purpose of this study was to examine the role of the blood–brain barrier and blood-cerebrospinal fluid barrier (BCSFB) in p-TA clearance from the brain. Methods In vivo [3H]p-TA elimination from rat cerebral cortex and from CSF was examined after intracerebral and intracerebroventricular administration, respectively. To evaluate BCSFB-mediated p-TA transport, [3H]p-TA uptake by isolated rat choroid plexus and conditionally immortalized rat choroid plexus epithelial cells, TR-CSFB3 cells, was performed. Results The half-life of [3H]p-TA elimination from rat CSF was found to be 2.9 min, which is 62-fold faster than that from rat cerebral cortex. In addition, this [3H]p-TA elimination from the CSF was significantly inhibited by co-injection of excess unlabeled p-TA. Thus, carrier-mediated p-TA transport process(es) are assumed to take part in p-TA elimination from the CSF. Since it is known that transporters at the BCSFB participate in compound elimination from the CSF, [3H]p-TA transport in ex vivo and in vitro models of rat BCSFB was examined. The [3H]p-TA uptake by isolated rat choroid plexus and TR-CSFB3 cells was time-dependent and was inhibited by unlabeled p-TA, indicating carrier-mediated p-TA transport at the BCSFB. The p-TA uptake by isolated choroid plexus and TR-CSFB3 cells was not reduced in the absence of extracellular Na+ and Cl−, and in the presence of substrates of typical organic cation transporters. However, this p-TA uptake was significantly inhibited by cationic drugs such as propranolol, imipramine, amantadine, verapamil, and pyrilamine. Moreover, p-TA uptake by TR-CSFB3 cells took place in an oppositely-directed H+ gradient manner. Therefore, this suggested that p-TA transport at the BCSFB involves cationic drug-sensitive transport systems which are distinct from typical plasma membrane organic cation transporters. Conclusion Our study indicates that p-TA elimination from the CSF is greater than that from the cerebral cortex. Moreover, it is suggested that cationic drug-sensitive transport systems in the BCSFB participate in this p-TA elimination from the CSF