A Molecular Mechanism for Abnormal Prion Protein Accumulation

A fundamental event in the pathogenesis of prion disease is the conversion of cellular prion protein into an abnormally folded isoform (PrPSc), which is the infectious causative agent of disease. With progression of disease, PrPSc is replicated and excessively accumulated in most cases. However, the molecular mechanism for excessive accumulation of PrPSc is not well understood. Recently, Sortilin, a member of the VPS10P domain receptor family, has been identified as a sorting receptor that directs prion protein (PrP) to the lysosomal degradation pathway. Moreover, it has been shown that prion infection impairs Sortilin function, resulting in delayed PrPSc degradation. In this chapter, we explain the mechanisms for PrP trafficking into the lysosomal degradation pathway mediated by Sortilin and overaccumulation of PrPSc caused by Sortilin dysfunction

Prion accumulation via sortilin dysfunction

Conformational conversion of the cellular prion protein, PrPC, into the abnormally folded isoform of prion protein, PrPSc, which leads to marked accumulation of PrPSc in brains, is a key pathogenic event in prion diseases, a group of fatal neurodegenerative disorders caused by prions. However, the exact mechanism of PrPSc accumulation in prion-infected neurons remains unknown. We recently reported a novel cellular mechanism to support PrPSc accumulation in prion-infected neurons, in which PrPSc itself promotes its accumulation by evading the cellular inhibitory mechanism, which is newly identified in our recent study. We showed that the VPS10P sorting receptor sortilin negatively regulates PrPSc accumulation in prion-infected neurons, by interacting with PrPC and PrPSc and trafficking them to lysosomes for degradation. However, PrPSc stimulated lysosomal degradation of sortilin, disrupting the sortilin-mediated degradation of PrPC and PrPSc and eventually evoking further accumulation of PrPSc in prion-infected neurons. These findings suggest a positive feedback amplification mechanism for PrPSc accumulation in prion-infected neurons

Intracellular secretion analysis of therapeutic antibodies in engineered high- producible CHO cells

The Chinese Hamster Ovary (CHO) cell is the most commonly used cell line for the production of therapeutic recombinant proteins. The improvements in target gene amplification and culture method have contributed in achieving a very high productivity. Some studies have focused on post-translational secretion processes, and overexpression of proteins which work in the secretion pathway successfully increased the productivity [1]. However, those studies were performed based on the knowledge obtained from the normal, adherent cultured cells, and the detailed secretion processes of recombinant proteins in engineered, suspension cultured cells is still unclear. To clarify problems and to find new targets for a more efficient establishment of high producers, the basic analyses about the secretion in engineered, high-producible CHO cells were performed. Please click Additional Files below to see the full abstract

Oviposition Factors of Ponticulothrips diospyrosi on Persimmon Seedling Leaves

The thrips Ponticulothrips diospyrosi Haga et Okajima is an univoltine species which aestivates and overwinters in the adult form in the fields. The oviposition factors of the thrips were investigated on persimmon seedling leaves. The adult female could make a gall and oviposit inside it in vitro. Female could make a gall and oviposit at 20℃, but only make a gall at 15℃. Although it could neither make a gall nor oviposit at 25℃, it oviposited at than temperature when placed on a gall. Female neither made a gall nor oviposited on an extended young leat. However, it could oviposit on the young leaf rolled artificially in a line tube (3.2 mm diam.), but not on the old one. These findings show that univoltine of the thrips may be regulated by the phenology of the host plant and females can oviposit whenever they are placed on the seedlings at the optimum oviposition temperature.カキ芽出し苗を用いてカキクダアザミウマ（Ponticulothrips diospyrosi Haga et Okajima）の産卵要因を解析した。羽化した新成虫は、高温及び低温条件を経なくても、本葉が展開する以前の苗があればゴールを形成し産卵した。温度に関しては、15℃、20℃でゴールを形成したが、15℃では産卵しなかった。しかし、15℃でゴールを形成した後、25℃に移すと産卵した。25℃ではゴールは形成されず、従って産卵もしなかった。日長は産卵に影響しなかった。本葉の展開した苗に雌成虫を放飼してもゴールは形成されず。産卵もしなかったが、展開直後の本葉を直径3.2mmのビーバーラインチューブに巻入れると産卵した。一方、老熟した本葉を巻入れても産卵しなかった。さらに、葉に食害痕のみられなかった場合にも産卵しなかった。以上の結果、野外で年一化の生活史をする本アザミウマの雌成虫の産卵には、高温長日及び低温短日を経る必要がなく、20℃～25℃で巻いた状態のカキの若葉が存在すれば産卵可能であると推定される

Neurotropic influenza A virus infection causes prion protein misfolding into infectious prions in neuroblastoma cells

Misfolding of the cellular prion protein, PrPC, into the amyloidogenic isoform, PrPSc, which forms infectious protein aggregates, the so-called prions, is a key pathogenic event in prion diseases. No pathogens other than prions have been identified to induce misfolding of PrPC into PrPSc and propagate infectious prions in infected cells. Here, we found that infection with a neurotropic influenza A virus strain (IAV/WSN) caused misfolding of PrPC into PrPSc and generated infectious prions in mouse neuroblastoma cells through a hit-and-run mechanism. The structural and biochemical characteristics of IAV/WSN-induced PrPSc were different from those of RML and 22L laboratory prions-evoked PrPSc, and the pathogenicity of IAV/WSN-induced prions were also different from that of RML and 22L prions, suggesting IAV/WSN-specific formation of PrPSc and infectious prions. Our current results may open a new avenue for the role of viral infection in misfolding of PrPC into PrPSc and formation of infectious prions

子宮筋層の内外層に発生する子宮腺筋症おける、それぞれの組織学的特徴

OBJECTIVE: To estimate the phenotypic characterization of fibrotic process in adenomyosis occurring at the inner or the outer myometrium. METHODS: Eight cases of adenomyosis occurring at the inner myometrium (Subtype I) and 10 cases of adenomyosis occurring at the outer myometrium (Subtype II), and 10 normal counterparts were used in this study. A immunohistochemical study for smooth muscle cells (SMCs) was performed using cytoskeletal proteins, Type I and III collagen, TGF-β and its signaling molecules. RESULTS: An increased expression of Type I collagen was observed in the extracellular matrix of adenomyotic foci. In normal uteri, immunostaining of SMC differentiation marker proteins (Desmin, Smoothelin, Myosin heavy chain (MHC)) were absent or only found in low numbers at the inner myometrium, while all of these marker proteins were clearly stained at the outer myometrium. In both types of adenomyotic foci, Desmin, Smoothelin, and MHC commonly showed a negative staining at the adjacent area to the glands. A significant staining of Non-muscle myosin IIB, TGF-β, and phosphorylated TGF-β type I receptors were found only at the SMCs of Subtype II adenomyosis. The Smad3/2 ratio of Subtype II adenomyosis was significantly higher than that of Subtype I. CONCLUSIONS: The inner myometrium of normal uteri was composed of undifferentiated phenotypes of SMCs, while the outer myometrium was composed of terminally differentiated SMCs. Various fibrotic processes have been suggested in the development of uterine adenomyosis. Distinct expression patterns of fibrosis related proteins have been shown to be implicated with differences in the subtypes of adenomyosis.博士（医学）・甲第681号・平成30年3月15日Copyright: © 2017 Kishi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

The localization and phosphorylation of p47 are important for Golgi disassembly–assembly during the cell cycle

In mammalian cells, the Golgi apparatus is disassembled at the onset of mitosis and reassembled at the end of mitosis. This disassembly–reassembly is generally believed to be essential for the equal partitioning of Golgi into two daughter cells. For Golgi disassembly, membrane fusion, which is mediated by NSF and p97, needs to be blocked. For the NSF pathway, the tethering of p115-GM130 is disrupted by the mitotic phosphorylation of GM130, resulting in the inhibition of NSF-mediated fusion. In contrast, the p97/p47 pathway does not require p115-GM130 tethering, and its mitotic inhibitory mechanism has been unclear. Now, we have found that p47, which mainly localizes to the nucleus during interphase, is phosphorylated on Serine-140 by Cdc2 at mitosis. The phosphorylated p47 does not bind to Golgi membranes. An in vitro assay shows that this phosphorylation is required for Golgi disassembly. Microinjection of p47(S140A), which is unable to be phosphorylated, allows the cell to keep Golgi stacks during mitosis and has no effect on the equal partitioning of Golgi into two daughter cells, suggesting that Golgi fragmentation-dispersion may not be obligatory for equal partitioning even in mammalian cells

Ethanolamine Is a New Anti-Prion Compound

Prion diseases are a group of fatal neurodegenerative disorders caused by accumulation of proteinaceous infectious particles, or prions, which mainly consist of the abnormally folded, amyloidogenic prion protein, designated PrPSc. PrPSc is produced through conformational conversion of the cellular isoform of prion protein, PrPC, in the brain. To date, no effective therapies for prion diseases have been developed. In this study, we incidentally noticed that mouse neuroblastoma N2a cells persistently infected with 22L scrapie prions, termed N2aC24L1-3 cells, reduced PrPSc levels when cultured in advanced Dulbecco’s modified eagle medium (DMEM) but not in classic DMEM. PrPC levels remained unchanged in prion-uninfected parent N2aC24 cells cultured in advanced DMEM. These results suggest that advanced DMEM may contain an anti-prion compound(s). We then successfully identified ethanolamine in advanced DMEM has an anti-prion activity. Ethanolamine reduced PrPSc levels in N2aC24L1-3 cells, but not PrPC levels in N2aC24 cells. Also, oral administration of ethanolamine through drinking water delayed prion disease in mice intracerebrally inoculated with RML scrapie prions. These results suggest that ethanolamine could be a new anti-prion compound

Structure of the inhibitor complex of old yellow enzyme from Trypanosoma cruzi

The structures of old yellow enzyme from Trypanosoma cruzi which produces prostaglandin F2α from PGH2 have been determined in the presence or absence of menadione

Vaporized Hydrogen Peroxide and Ozone Gas Synergistically Reduce Prion Infectivity on Stainless Steel Wire

Prions are infectious agents causing prion diseases, which include Creutzfeldt–Jakob disease (CJD) in humans. Several cases have been reported to be transmitted through medical instruments that were used for preclinical CJD patients, raising public health concerns on iatrogenic transmissions of the disease. Since preclinical CJD patients are currently difficult to identify, medical instruments need to be adequately sterilized so as not to transmit the disease. In this study, we investigated the sterilizing activity of two oxidizing agents, ozone gas and vaporized hydrogen peroxide, against prions fixed on stainless steel wires using a mouse bioassay. Mice intracerebrally implanted with prion-contaminated stainless steel wires treated with ozone gas or vaporized hydrogen peroxide developed prion disease later than those implanted with control prion-contaminated stainless steel wires, indicating that ozone gas and vaporized hydrogen peroxide could reduce prion infectivity on wires. Incubation times were further elongated in mice implanted with prion-contaminated stainless steel wires treated with ozone gas-mixed vaporized hydrogen peroxide, indicating that ozone gas mixed with vaporized hydrogen peroxide reduces prions on these wires more potently than ozone gas or vaporized hydrogen peroxide. These results suggest that ozone gas mixed with vaporized hydrogen peroxide might be more useful for prion sterilization than ozone gas or vaporized hydrogen peroxide alone