Long-term territoriality and mate acquisition in the lefteye flounder Engyprosopon grandisquama

Reproductive ecology and function of long-term territoriality in the lefteye flounder Engyprosopon grandisquama were investigated in the southwest of Kyushu Island, Japan. Field observations of marked individuals and monthly sampling suggested that the spawning season was from June to September with a peak in June–July. During the spawning season, males maintained their mating territories, although spawning behavior was not observed in August–September. Some males stayed until the next spawning season and then acquired more mates than newly appearing males, most of which could not acquire mates. Long-term retention of territory may be more advantageous for establishing a mating territory and acquiring mates in the next spawning season.     

Semaphorin3A released from human dental pulp cells inhibits the increase in interleukin-6 and CXC chemokine ligand 10 production induced by tumor necrosis factor-α through suppression of nuclear factor-κB activation

Human dental pulp cells (HDPCs) play an important role in pulpitis. Semaphorin3A (Sema3A), which is an axon guidance molecule, is a member of the secretory semaphorin family. Recently, Sema3A has been reported to be an osteoprotective factor and to be involved in the immune response. However, the role of Sema3A in dental pulp inflammation remains unknown. The aim of this study was to reveal the existence of Sema3A in human dental pulp tissue and the effect of Sema3A which is released from tumor necrosis factor (TNF)-α-stimulated HDPCs on production of proinflammatory cytokines, such as interleukin (IL)-6 and CXC chemokine ligand 10 (CXCL10), from HDPCs stimulated with TNF-α. Sema3A was detected in inflamed pulp as compared to normal pulp. HDPCs expressed Neuropilin-1(Nrp1) which is Sema3A receptor. TNF-α increased the levels of IL-6 and CXCL10 in HDPCs in time-dependent manner. Sema3A inhibited production of these two cytokines from TNF-α-stimulated HDPCs. TNF-α induced soluble Sema3A production from HDPCs. Moreover, antibody-based neutralization of Sema3A further promoted production of IL-6 and CXCL10 from TNF-α-stimulated HDPCs. Sema3A inhibited nuclear factor (NF)-κB P65 phosphorylation and inhibitor κBα degradation in TNF-α-stimulated HDPCs. These results indicated that Sema3A is induced in human dental pulp, and TNF-α acts on HDPCs to produce Sema3A, which partially inhibits the increase in IL-6 and CXCL10 production induced by TNF-α, and that the inhibition leads to suppression of NF-κB activation. Therefore, it is suggested that Sema3A may regulate inflammation in dental pulp and be novel antiinflammatory target molecule for pulpitis.     

The inositol 5-phosphatase SHIP2 is an effector of RhoA and is involved in cell polarity and migration

Cell migration is essential for various physiological and pathological processes. Polarization in motile cells requires the coordination of several key signaling molecules, including RhoA small GTPases and phosphoinositides. Although RhoA participates in a front-rear polarization in migrating cells, little is known about the functional interaction between RhoA and lipid turnover. We find here that src-homology 2-containing inositol-5-phosphatase 2 (SHIP2) interacts with RhoA in a GTP-dependent manner. The association between SHIP2 and RhoA is observed in spreading and migrating U251 glioma cells. The depletion of SHIP2 attenuates cell polarization and migration, which is rescued by wild-type SHIP2 but not by a mutant defective in RhoA binding. In addition, the depletion of SHIP2 impairs the proper localization of phosphatidylinositol 3,4,5-trisphosphate, which is not restored by a mutant defective in RhoA binding. These results suggest that RhoA associates with SHIP2 to regulate cell polarization and migration.     

In Vivo Role of Phosphorylation of Cryptochrome 2 in the Mouse Circadian Clock

The circadian clock is finely regulated by posttranslational modifications of clock components. Mouse CRY2, a critical player in the mammalian clock, is phosphorylated at Ser557 for proteasome-mediated degradation, but its in vivo role in circadian organization was not revealed. Here, we generated CRY2(S557A) mutant mice, in which Ser557 phosphorylation is specifically abolished. The mutation lengthened free-running periods of the behavioral rhythms and PER2::LUC bioluminescence rhythms of cultured liver. In livers from mutant mice, the nuclear CRY2 level was elevated, with enhanced PER2 nuclear occupancy and suppression of E-box-regulated genes. Thus, Ser557 phosphorylation-dependent regulation of CRY2 is essential for proper clock oscillation in vivo.     

OCA4: evidence for a founder effect for the p.D157N mutation of the MATP gene in Japanese and Korean

Oculocutaneous albinism type 4 (OCA4) was identified as a rare form of human OCA among a group of autosomal recessive hypopigmentary disorders. Little is known about the prevailing distribution of patients of OCA4 with mutations of the MATP gene, although one Turkish, five German, one Korean, and 18 Japanese patients have been reported so far. The p.D157N mutation was previously reported to be the most frequent (0.389; 14/36) in Japanese patients and was also found in a Korean patient. On the other hand, this mutation has not been found in Turkish and German patients. We therefore investigated haplotypes of the patients who have the p.D157N mutation. The results showed that OCA4 is prevalent in East Asia including Japan and Korea likely as a result of a founder effect for the p.D157N mutation. Furthermore, it is suspected that the p.D157N mutation might have occurred on an ancestral chromosome after the divergence of Orientals and Caucasians.     

Excess peroxisomes are degraded by autophagic machinery in mammals

Peroxisomes are degraded by autophagic machinery termed "pexophagy" in yeast; however, whether this is essential for peroxisome degradation in mammals remains unknown. Here we have shown that Atg7, an essential gene for autophagy, plays a pivotal role in the degradation of excess peroxisomes in mammals. Following induction of peroxisomes by a 2-week treatment with phthalate esters in control and Atg7-deficient livers, peroxisomal degradation was monitored within 1 week after discontinuation of phthalate esters. Although most of the excess peroxisomes in the control liver were selectively degraded within 1 week, this rapid removal was exclusively impaired in the mutant liver. Furthermore, morphological analysis revealed that surplus peroxisomes, but not mutant hepatocytes, were surrounded by autophagosomes in the control. Our results indicated that the autophagic machinery is essential for the selective clearance of excess peroxisomes in mammals. This is the first direct evidence for the contribution of autophagic machinery in peroxisomal degradation in mammals.     

RNA-based cooperative protein labeling that permits direct monitoring of the intracellular concentration change of an endogenous protein

Imaging the dynamics of proteins in living cells is a powerful means for understanding cellular functions at a deeper level. Here, we report a versatile method for spatiotemporal imaging of specific endogenous proteins in living mammalian cells. The method employs a bifunctional aptamer capable of selective protein recognition and fluorescent probe-binding, which is induced only when the aptamer specifically binds to its target protein. An aptamer for β-actin protein preferentially recognizes its monomer forms over filamentous forms, resulting in selective G-actin staining in both fixed and living cells. Through actin-drug treatment, the method permitted direct monitoring of the intracellular concentration change of endogenous G-actin. This protein-labeling method, which is highly selective and non-covalent, provides rich insights into the study of spatiotemporal protein dynamics in living cells.     

Skeletal defects in VEGF(120/120) mice reveal multiple roles for VEGF in skeletogenesis

Angiogenesis is an essential component of skeletal development and VEGF signaling plays an important if not pivotal role in this process. Previous attempts to examine the roles of VEGF in vivo have been largely unsuccessful because deletion of even one VEGF allele leads to embryonic lethality before skeletal development is initiated. The availability of mice expressing only the VEGF120 isoform (which do survive to term) has offered an opportunity to explore the function of VEGF during embryonic skeletal development. Our study of these mice provides new in vivo evidence for multiple important roles of VEGF in both endochondral and intramembranous bone formation, as well as some insights into isoform-specific functions. There are two key differences in vascularization of developing bones between wild-type and VEGF(120/120) mice. VEGF(120/120) mice have not only a delayed recruitment of blood vessels into the perichondrium but also show delayed invasion of vessels into the primary ossification center, demonstrating a significant role of VEGF at both an early and late stage of cartilage vascularization. These findings are the basis for a two-step model of VEGF-controlled vascularization of the developing skeleton, a hypothesis that is supported by the new finding that VEGF is expressed robustly in the perichondrium and surrounding tissue of cartilage templates of future bones well before blood vessels appear in these regions. We also describe new in vivo evidence for a possible role of VEGF in chondrocyte maturation, and document that VEGF has a direct role in regulating osteoblastic activity based on in vivo evidence and organ culture experiments.