Synthetic LXR agonist inhibits the development of atherosclerosis in New Zealand White rabbits

The nuclear receptors Liver X receptors, LXRα and LXRβ, regulate cholesterol and triglyceride metabolism. We and others have previously reported that synthetic LXR agonists reduced atherosclerosis in models of mouse with no detectable plasma cholesteryl ester transfer protein (CETP) activity, which plays an important role in reverse cholesterol transport. In the present study, we investigated the effect of LXR activation in rabbits to elucidate the influence of CETP activity. First, we cloned rabbit LXRs cDNA. The data indicated that rabbit LXRα was mostly highly expressed in the liver, whereas LXRβ expression was ubiquitous. Next, we investigated the effect of LXR agonist on lipid levels. Treatment with LXR agonist T0901317 increased plasma CETP activity and consequently elevated LDL, but no change in HDL. High cholesterol (HC) diet-feeding, which is thought to provide oxysterols as the natural agonists, could also increase expression of CETP and other LXR target genes. Finally, we tested T0901317 in the atherosclerosis intervention study. Chronic administration of T0901317 significantly reduced atherosclerosis in HC diet-fed rabbits despite less favorable lipid profiles, i.e. increases of plasma triglycerides and no change of HDL. T0901317 induced ATP-binding cassette transporters ABCA1 and ABCG1 and suppressed inflammatory genes expression in the aorta, suggesting that direct actions of LXR agonist on vascular gene expression are likely to contribute to the antiatherogenic effect. The present work strongly supports the idea that LXR agonists could be beneficial as therapeutic agents for treatment of atherosclerosis.     

Roles of rat and human aldo-keto reductases in metabolism of farnesol and geranylgeraniol

Farnesol (FOH) and geranylgeraniol (GGOH) with multiple biological actions are produced from the mevalonate pathway, and catabolized into farnesoic acid and geranylgeranoic acid, respectively, via the aldehyde intermediates (farnesal and geranylgeranial). We investigated the intracellular distribution, sequences and properties of the oxidoreductases responsible for the metabolic steps in rat tissues. The oxidation of FOH and GGOH into their aldehyde intermediates were mainly mediated by alcohol dehydrogenases 1 (in the liver and colon) and 7 (in the stomach and lung), and the subsequent step into the carboxylic acids was catalyzed by a microsomal aldehyde dehydrogenase. In addition, high reductase activity catalyzing the aldehyde intermediates into FOH (or GGOH) was detected in the cytosols of the extra-hepatic tissues, where the major reductase was identified as aldo-keto reductase (AKR) 1C15. Human reductases with similar specificity were identified as AKR1B10 and AKR1C3, which most efficiently reduced farnesal and geranylgeranial among seven enzymes in the AKR1A-1C subfamilies. The overall metabolism from FOH to farnesoic acid in cultured cells was significantly decreased by overexpression of AKR1C15, and increased by addition of AKR1C3 inhibitors, tolfenamic acid and R-flurbiprofen. Thus, AKRs (1C15 in rats, and 1B10 and 1C3 in humans) may play an important role in controlling the bioavailability of FOH and GGOH.     

Neuroprotective Effects of Lacosamide and Memantine on Hyperoxic Brain Injury in Rats

Neurochemical Research - In neonates supraphysiological oxygen therapy has been demonstrated to cause neuronal death in hippocampus, prefrontal cortex, parietal cortex, and retrosplenial cortex....     

The Golgin Tether Giantin Regulates the Secretory Pathway by Controlling Stack Organization within Golgi Apparatus

Golgins are coiled-coil proteins that play a key role in the regulation of Golgi architecture and function. Giantin, the largest golgin in mammals, forms a complex with p115, rab1, GM130, and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs), thereby facilitating vesicle tethering and fusion processes around the Golgi apparatus. Treatment with the microtubule destabilizing drug nocodazole transforms the Golgi ribbon into individual Golgi stacks. Here we show that siRNA-mediated depletion of giantin resulted in more dispersed Golgi stacks after nocodazole treatment than by control treatment, without changing the average cisternal length. Furthermore, depletion of giantin caused an increase in cargo transport that was associated with altered cell surface protein glycosylation. Drosophila S2 cells are known to have dispersed Golgi stacks and no giantin homolog. The exogenous expression of mammalian giantin cDNA in S2 cells resulted in clustered Golgi stacks, similar to the Golgi ribbon in mammalian cells. These results suggest that the spatial organization of the Golgi ribbon is mediated by giantin, which also plays a role in cargo transport and sugar modifications.     

Food exchange behavior between multiple founding queens of Polyrhachis moesta (Hymenoptera: Formicidae) changes during hibernation

In some ant colonies founded by multiple queens, genetically unrelated queens cooperate to establish the colony. To test whether founding queens differentially adjust the amount of food exchange to nestmate and non-nestmate Polyrhachis moesta (Emery) queens before and after hibernation, food exchange in founding queens with different nutritional conditions was investigated. The proportion of non-nestmate queens showing food-begging behavior before hibernation was higher than that of nestmate queens. The number of begging behaviors was greater after hibernation than before hibernation, both between nestmates and between non-nestmates. Weight loss in fed queens performing food exchange with nestmate queens was significantly greater after hibernation than before hibernation. These results suggest that founding queens can discriminate between nestmate and non-nestmate founding queens and change the level of cooperation with founding queens before and after hibernation.     

Introduction of selective intersubunit disulfide bonds into self‐assembly protein scaffold to enhance an artificial multienzyme complex's activity

In nature, many enzymes participating in multienzyme reactions are often assembled to enhance efficiencies of multiple reactions. Therefore, much attention has been focused on self‐assembly of multiple enzymes fused with a protein/peptide that interacts with a specific protein to enhance artificial multienzyme reactions. Sulfolobus solfataricus proliferating cell nuclear antigen (PCNA) is a ring‐shaped symmetric heterotrimer consisting of PCNA1, PCNA2 and PCNA3. Multiple enzymes can be co‐localized on the PCNA ring by fusing them to the C‐termini of the three PCNA subunits. However, an advantage of the specific non‐covalent complex formation is inextricably associated with the disadvantage of its concentration‐dependent dissociation. In this study, disulfide bonds were introduced between the PCNA subunits by Cys substitution at the sites neighboring the interface for heterotrimerization. Selective intersubunit disulfide bond formation between PCNA1 and PCNA3 and between PCNA2 and PCNA3 by a natural oxidizing reagent successfully stabilized an artificial multienzyme complex, which is composed of a bacterial cytochrome P450 and its two redox partner proteins. The covalent stabilization of the multienzyme complex enhanced its cytochrome P450 activity because of the absence of inactive dissociated components. Biotechnol. Bioeng. 2013; 110: 1858–1864. © 2013 Wiley Periodicals, Inc.     

Discovery of 2,8-diazaspiro[4.5]decane-based trisubstituted urea derivatives as highly potent soluble epoxide hydrolase inhibitors and orally active drug candidates for treating hypertension

We identified 2,8-diazaspiro[4.5]decane-based trisubstituted urea derivatives as highly potent soluble epoxide hydrolase (sEH) inhibitors and orally active agents for treating hypertension. Docking studies using human and murine sEH X-ray crystal structures revealed steric hindrance around the side chain of Phe406 of murine sEH. The trifluoromethyl moiety (11) was replaced with a trifluoromethoxy moiety (12) to prevent steric clash, and improved murine sEH inhibitory activity was observed. The oral administration of 12, 20, and 37 at a dose of 30 mg/kg reduced blood pressure in spontaneously hypertensive rat, but had little effect on blood pressure in normotensive rat.     

3′-Hydroxy T-2 and 3′-Hydroxy HT-2 Toxins: New Metabolites of T-2 Toxin,a Trichothecene Mycotoxin,in Animals

A microorganism producing transglutaminase was screened as an indication of hydroxamate- forming activity. The microbial transglutaminase was purified from the culture filtrate of the strain, S- 8112, which was supposed to belong to the genus Streptoverticillium. The molecular weight of the purified enzyme was found to be about 40,000 on SDS-polyacrylamide gel electrophoresis, the isoelectric point 8.9 and the optimal pH of the reaction 6~7. The present enzyme requires no calcium ions for its activity. Thus, it clearly differs from known transglutaminases derived from mammalian organs, which have been defined as calcium-dependent enzymes.     

Neural Progenitor Cells Undergoing Yap/Tead-Mediated Enhanced Self-Renewal Form Heterotopias More Easily in the Diencephalon than in the Telencephalon

Spatiotemporally ordered production of cells is essential for brain development. Normally, most undifferentiated neural progenitor cells (NPCs) face the apical (ventricular) surface of embryonic brain walls. Pathological detachment of NPCs from the apical surface and their invasion of outer neuronal territories, i.e., formation of NPC heterotopias, can disrupt the overall structure of the brain. Although NPC heterotopias have previously been observed in a variety of experimental contexts, the underlying mechanisms remain largely unknown. Yes-associated protein 1 (Yap1) and the TEA domain (Tead) proteins, which act downstream of Hippo signaling, enhance the stem-like characteristics of NPCs. Elevated expression of Yap1 or Tead in the neural tube (future spinal cord) induces massive NPC heterotopias, but Yap/Tead-induced expansion of NPCs in the developing brain has not been previously reported to produce NPC heterotopias. To determine whether NPC heterotopias occur in a regionally characteristic manner, we introduced the Yap1-S112A or Tead-VP16 into NPCs of the telencephalon and diencephalon, two neighboring but distinct forebrain regions, of embryonic day 10 mice by in utero electroporation, and compared NPC heterotopia formation. Although NPCs in both regions exhibited enhanced stem-like behaviors, heterotopias were larger and more frequent in the diencephalon than in the telencephalon. This result, the first example of Yap/Tead-induced NPC heterotopia in the forebrain, reveals that Yap/Tead-induced NPC heterotopia is not specific to the neural tube, and also suggests that this phenomenon depends on regional factors such as the three-dimensional geometry and assembly of these cells.