O-Yu Kwon

Drosophila short neuropeptide F signalling regulates growth by ERK-mediated insulin signalling.

Insulin and insulin growth factor have central roles in growth, metabolism and ageing of animals, including Drosophila melanogaster. In Drosophila, insulin-like peptides (Dilps) are produced by specialized neurons in the brain. Here we show that Drosophila short neuropeptide F (sNPF), an orthologue of mammalian neuropeptide Y (NPY), and sNPF receptor sNPFR1 regulate expression of Dilps. Body size was increased by overexpression of sNPF or sNPFR1. The fat body of sNPF mutant Drosophila had downregulated Akt, nuclear localized FOXO, upregulated translational inhibitor 4E-BP and reduced cell size. Circulating levels of glucose were elevated and lifespan was also extended in sNPF mutants. We show that these effects are mediated through activation of extracellular signal-related kinases (ERK) in insulin-producing cells of larvae and adults. Insulin expression was also increased in an ERK-dependent manner in cultured Drosophila central nervous system (CNS) cells and in rat pancreatic cells treated with sNPF or NPY peptide, respectively. Drosophila sNPF and the evolutionarily conserved mammalian NPY seem to regulate ERK-mediated insulin expression and thus to systemically modulate growth, metabolism and lifespan.

Minibrain/Dyrk1a Regulates Food Intake through the Sir2-FOXO-sNPF/NPY Pathway in Drosophila and Mammals

Feeding behavior is one of the most essential activities in animals, which is tightly regulated by neuroendocrine factors. Drosophila melanogaster short neuropeptide F (sNPF) and the mammalian functional homolog neuropeptide Y (NPY) regulate food intake. Understanding the molecular mechanism of sNPF and NPY signaling is critical to elucidate feeding regulation. Here, we found that minibrain (mnb) and the mammalian ortholog Dyrk1a target genes of sNPF and NPY signaling and regulate food intake in Drosophila melanogaster and mice. In Drosophila melanogaster neuronal cells and mouse hypothalamic cells, sNPF and NPY modulated the mnb and Dyrk1a expression through the PKA-CREB pathway. Increased Dyrk1a activated Sirt1 to regulate the deacetylation of FOXO, which potentiated FOXO-induced sNPF/NPY expression and in turn promoted food intake. Conversely, AKT-mediated insulin signaling suppressed FOXO-mediated sNPF/NPY expression, which resulted in decreasing food intake. Furthermore, human Dyrk1a transgenic mice exhibited decreased FOXO acetylation and increased NPY expression in the hypothalamus, as well as increased food intake. Our findings demonstrate that Mnb/Dyrk1a regulates food intake through the evolutionary conserved Sir2-FOXO-sNPF/NPY pathway in Drosophila melanogaster and mammals.

Mucilaginibacter angelicae sp. nov., isolated from the rhizosphere of Angelica polymorpha Maxim

A Gram-negative-staining, non-motile rod, designated GG-w14(T), was isolated from the rhizosphere of Angelica polymorpha Maxim. Phylogenetic analysis of 16S rRNA gene sequences revealed that the isolate belonged to the genus Mucilaginibacter and exhibited 93.9-97.4% 16S rRNA gene sequence similarity with recognized members of the genus Mucilaginibacter (closest relative Mucilaginibacter gossypii Gh-67(T)). DNA-DNA relatedness between strain GG-w14(T) and M. gossypii KCTC 22380(T) was <41%. Strain GG-w14(T) grew at 4-35 °C, at pH 5.0-8.0 and with 0-1% (w/v) NaCl. The isolate hydrolysed casein, CM-cellulose and starch and contained menaquinone 7 as the major menaquinone. The major cellular fatty acids were summed feature 3 (C(16:1)ω7c and/or iso-C(15:0) 2-OH; 39.9%), iso-C(15:0) (24.2%) and iso-C(17:0) 3-OH (12.4%). The DNA G+C content was 42.5 mol%. These data suggest that strain GG-w14(T) should be considered as a representative of a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter angelicae sp. nov. is proposed. The type strain is GG-w14(T) (=KCTC 23250(T)=NCAIM B 02415(T)).

Molecular cloning and characterization of a cDNA encoding a transferrin homolog from Bombyx mori.

Abstract We isolated a cDNA representing a message that was strongly induced by injection with E. coli in Bombyx mori. The 2160 bp cDNA has an open reading frame of 644 amino acids and the deduced product a predicted molecular mass of 71 kDa. The cDNA sequence shared high homology with the transferrins known so far, and its deduced peptide had unique features of transferrins, that is, sites of cystein residues and iron binding. We suggest that the B. mori transferrin plays an important role in the self-defense system.

Delayed postanoxic encephalopathy after carbon monoxide poisoning

Delayed postanoxic encephalopathy causes deterioration and relapse of cognitive ability and behavioural movement a few weeks after complete recovery from initial hypoxic injury. A case is reported of delayed postanoxic encephalopathy after carbon monoxide poisoning, which was diagnosed with diffusion weighted magnetic resonance imaging. The literature is also reviewed.

Processed short neuropeptide F peptides regulate growth through the ERK-insulin pathway in Drosophila melanogaster.

The Drosophila sNPF gene regulates growth through the ERK‐insulin pathway. sNPF encodes a precursor protein that is processed and produces biologically active sNPF peptides. However, the functions of these peptides are not known. In Drosophila neuronal cells in culture and in flies in vivo, sNPF1 and sNPF2 activated the ERK‐insulin pathway and regulated body growth. In addition, the sNPF precursor and the processed sNPF peptide were co‐localized in the neurons of the central nervous system. These results indicate that sNPF1 and sNPF2 peptides processed from the sNPF precursor are sufficient for regulating body growth through the ERK‐insulin pathway in Drosophila.

Bombyx mori transferrin: genomic structure, expression and antimicrobial activity of recombinant protein.

Transferrin (Tf) is a multifunctional, iron binding protein found in both vertebrates and invertebrates. Although transferrin has been suggested to play a role in innate immunity, its immunological function during infection has not been characterized. In this study, we identified and characterized Bombyx mori transferrin (BmTf). The promoter region of BmTf has numerous putative NF-kappaB binding sites, suggesting its possible function in innate immunity. Analysis of BmTf gene expression shows that it is highly inducible in response to a wide variety of pathogens including bacteria, fungus, and viruses. Recombinant BmTf protein produced in a baculovirus system exhibits iron binding capacity and antibacterial activity against various Gram-positive and -negative bacteria. Taken together, our results indicate that BmTf is an inducible immune effector molecule that may play an important role in pathogen clearance of insect innate immunity.

Molecular characterization of a Bombyx mori protein disulfide isomerase (bPDI)

Abstract We have isolated a complementary deoxyribonucleic acid clone that encodes the protein disulfide isomerase of Bombyx mori (bPDI). This protein has a putative open reading frame of 494 amino acids and a predicted size of 55.6 kDa. In addition, 2 thioredoxin active sites, each with a CGHC sequence, and an endoplasmic reticulum (ER) retention signal site with a KDEL motif were found at the C-terminal. Both sites are typically found in members of the PDI family of proteins. The expression of bPDI messenger ribonucleic acid (mRNA) was markedly increased during ER stress induced by stimulation with calcium ionophore A23187, tunicamycin, and dithiothreitol, all of which are known to cause an accumulation of unfolded proteins in the ER. We also examined the tissue distribution of bPDI mRNA and found pronounced expression in the fat body of insects. Hormonal regulation studies showed that juvenile hormone, insulin, and a combination of juvenile hormone and transferrin (although not transferrin alone) affected bPDI mRNA expression. A challenge with exogenous bacteria also affected expression, and the effect peaked 16 hours after infection. These results suggest that bPDI is a member of the ER-stress protein group, that it may play an important role in exogenous bacterial infection of the fat body, and that its expression is hormone regulated.

Overexpression of ERp29 in the thyrocytes of FRTL-5 cells

AbstractIt was previously reported that the up-regulation of ERp29 mRNA depends on the levels of thyroid stimulating hormone (TSH) in the thyrocytes of FRTL-5 cells. In order to investigate the putative new function of ERp29 as an endoplasmic molecular (ER) chaperone, an ERp29-overexpressing FRTL-5 cell line was established. This cell line had approximately three times the levels of ERp29 protein and an enhanced level of thyroglobulin (Tg) secretion. The results showed both enhanced ERp29 expression and an interaction with the other ER chaperones such as GRP94, BiP, ERp72 and calnexin. In addition, ERp29 enhanced the expression of PKR-like ER kinase (PERK), which is a transmembrane protein located in the ER membrane. These findings suggest that ERp29 assists in protein folding as well as in the secretion of the secretory/plasma membrane proteins under close co-operation with other ER chaperones and the ER stress signaler, PERK.

Photoexcited Porphyrins as a Strong Suppressor of β‐Amyloid Aggregation and Synaptic Toxicity

The abnormal assembly of β-amyloid (Aβ) peptides into neurotoxic, β-sheet-rich amyloid aggregates is a major pathological hallmark of Alzheimers disease (AD). Light-induced photosensitizing molecules can regulate Aβ amyloidogenesis. Multiple photochemical analyses using circular dichroism, atomic force microscopy, dot blot, and native gel electrophoresis verified that photoactivated meso-tetra(4-sulfonatophenyl)porphyrin (TPPS with M = 2H(+), Zn(2+), Cu(2+), Mn(2+)) successfully inhibits Aβ aggregation in vitro. Furthermore, Aβ toxicity was relieved in the photoexcited-TPPS-treated Drosophila AD model. TPPS suppresses neural cell death, synaptic toxicity, and behavioral defects in the Drosophila AD model under blue light illumination. Behavioral phenotypes, including larval locomotion defect and short lifespan caused by Aβ overexpression, were also rescued by blue light-excited TPPS.