Immunophilin ligands prevent H2O2-induced apoptotic cell death by increasing glutathione levels in neuro 2A neuroblastoma cells.

We examined the effects of FK506 and its non-immunosuppressive derivative, GPI1046, on H2O2-induced reduction of cell viability and apoptotic cell death in Neuro 2A cells. Our results suggest that the protective properties of GPI1046 against H2O2-induced reduction of cell viability are equipotent with those of FK506 and may be mediated by increased intracellular concentrations of glutathione (GSH). In addition, both FK506 and GPI1046 prevented apoptotic cell death in Neuro 2A cells, although the antiapoptotic effect of FK506 was somewhat stronger than that of GPI1046. These findings suggest that non-immunosuppressive immunophilin ligands such as GPI1046 might be potentially useful in treatment of neurodegenerative diseases without serious side effects such as immune deficiency.</p

Application of Single Prolonged Stress Induces Post-traumatic Stress Disorder-like Characteristics in Mice

We tried to clarify the applicability of a single prolonged stress (SPS) protocol as post-traumatic stress disorder (PTSD) model in mice. To investigate PTSD pathophysiology, we conducted hypothalamo-pituitary-adrenal (HPA) negative feedback testing at 1, 4, 8 and 12 weeks after the SPS by administrating a dexamethasone (DEX) suppression test. The SPS induced over-suppression of the HPA system by DEX treatment at 8 and 12 weeks. To investigate PTSD-like behavioral characteristics, we subjected mice to testing in a light/dark box (to assess anxiety), a Y-maze (working memory), a cliff avoidance (visual cognition), and an open field (locomotor activity) at 1, 4, 8 and 12 weeks after the SPS. In the light/dark box test, the SPS-applied mice spent significantly less time in the light box at 8 or 12 weeks. In the cliff avoidance test, the SPS-applied mice spent significantly less time in the open area at 1 week. However, in both the Y-maze test and the open field test, SPS-applied mice tended toward slight decreases in a time-dependent manner until 12 weeks. Therefore, SPS-applied mice may thus be useful for assessing characteristics relevant to PTSD that coincide with changes in the HPA axis

The Molecule Role Ontology: An Ontology for Annotation of Signal Transduction Pathway Molecules in the Scientific Literature

In general, it is not easy to specify a single sequence identity for each molecule name that appears in a pathway in the scientific literature. A molecule name may stand for concepts of various granularities, from concrete objects such as H-Ras and ERK1 to abstract concepts or categories such as Ras and MAPK. Typically, the relations among molecule names derive a hierarchical structure; without a proper way to handle this knowledge, it becomes ever more difficult to develop a reliable pathway database. This paper describes an ontology that is designed to annotate molecules in the scientific literature on signal transduction pathways

Cdc42 regulates cell polarization and contractile actomyosin rings during terminal differentiation of human erythroblasts

The molecular mechanisms involved in the terminal differentiation of erythroblasts have been elucidated by comparing enucleation and cell division. Although various similarities and differences between erythroblast enucleation and cytokinesis have been reported, the mechanisms that control enucleation remain unclear. We previously reported that dynein and microtubule-organizing centers mediated the polarization of nuclei in human erythroblasts. Moreover, the accumulation of F-actin was noted during the enucleation of erythroblasts. Therefore, during enucleation, upstream effectors in the signal transduction pathway regulating dynein or actin, such as cell division control protein 42 homolog (Cdc42), may be crucial. We herein investigated the effects of the Cdc42 inhibitor, CASIN, on cytokinesis and enucleation in colony-forming units-erythroid (CFU-Es) and mature erythroblasts (day 10). CASIN blocked the proliferation of CFU-Es and their enucleation in a dose-dependent manner. Dynein adopted an island-like distribution in the cytoplasm of non-treated CFU-Es, but was concentrated near the nucleus as a dot and co-localized with gamma -tubulin in CASIN-treated cells. CASIN blocked the accumulation of F-actin in CFU-Es and day 10 cells. These results demonstrated that Cdc42 plays an important role in cytokinesis, nuclear polarization and nuclear extrusion through a relationship with dynein and actin filament organization during the terminal differentiation of erythroblasts

Geochemical characteristics of back-arc basin lower crust and upper mantle at final spreading stage of Shikoku Basin: an example of Mado Megamullion

AbstractThis paper explores the evolutional process of back-arc basin (BAB) magma system at final spreading stage of extinct BAB, Shikoku Basin (Philippine Sea) and assesses its tectonic evolution using a newly discovered oceanic core complex, the Mado Megamullion. Bulk and in-situ chemical compositions together with in-situ Pb isotope composition of dolerite, oxide gabbro, gabbro, olivine gabbro, dunite, and peridotite are presented. Compositional ranges and trends of the igneous and peridotitic rocks from the Mado Megamullion are similar to those from the slow- to ultraslow-spreading mid-ocean ridges (MOR). Since the timing of the Mado Megamullion exhumation corresponds to the very end of the Shikoku Basin opening, the magma supply was subdued and highly episodic, leading to extreme magma differentiation to form ferrobasaltic, hydrous magmas. In-situ Pb isotope composition of magmatic brown amphibole in the oxide gabbro is identical to that of depleted source mantle for mid-ocean ridge basalt (MORB). In the context of hydrous BAB magma genesis, the magmatic water was derived solely from the MORB source mantle. The distance from the back-arc spreading center to the arc front increased away through maturing of the Shikoku Basin to cause MORB-like magmatism. After the exhumation of Mado Megamullion along detachment faults, dolerite dikes intruded as a post-spreading magmatism. The final magmatism along with post-spreading Kinan Seamount Chain volcanism were introduced around the extinct back-arc spreading center after the opening of Shikoku Basin by residual mantle upwelling

Endothelial PI3K-C2α, a class II PI3K, has an essential role in angiogenesis and vascular barrier function

The class II α-isoform of phosphatidylinositol 3-kinase (PI3K-C2α) is localized in endosomes, the trans-Golgi network and clathrin-coated vesicles; however, its functional role is not well understood. Global or endothelial-cell-specific deficiency of PI3K-C2α resulted in embryonic lethality caused by defects in sprouting angiogenesis and vascular maturation. PI3K-C2α knockdown in endothelial cells resulted in a decrease in the number of PI3-phosphate-enriched endosomes, impaired endosomal trafficking, defective delivery of VE-cadherin to endothelial cell junctions and defective junction assembly. PI3K-C2α knockdown also impaired endothelial cell signaling, including vascular endothelial growth factor receptor internalization and endosomal RhoA activation. Together, the effects of PI3K-C2α knockdown led to defective endothelial cell migration, proliferation, tube formation and barrier integrity. Endothelial PI3K-C2α deficiency in vivo suppressed postischemic and tumor angiogenesis and diminished vascular barrier function with a greatly augmented susceptibility to anaphylaxis and a higher incidence of dissecting aortic aneurysm formation in response to angiotensin II infusion. Thus, PI3K-C2α has a crucial role in vascular formation and barrier integrity and represents a new therapeutic target for vascular disease.In Press / 2013-03-18公開予定

PHOSPHATIDYLINOSITOL 3,5-BISPHOSPHATE IS AN ESSENTIAL REGULATOR OF LYSOSOME MORPHOLOGY

Phosphoinositides are lipid second messengers that act as key players in endosomal membrane trafficking, and mutations in several phosphatases that metabolize these lipids cause severe genetic diseases. We previously reported that type III phosphatidylinositol phosphate kinase (PIPKIII) is a critical regulator of lysosome size. However, the lipid products that mediate PIPKIII function have not been well characterized. Using a series of phosphoinositide phosphatase expression vectors, we show here that phosphatidylinositol 3,5-bisphosphate is the obligatory lipid for lysosome morphology