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Volume 43 (2018)
- Issue 6 Pages 252-
- Issue 5 Pages 194-
- Issue 4 Pages 122-
- Issue 3 Pages 80-
- Issue 2 Pages 34-
- Issue 1 Pages 2-
Volume 43, Issue 5
Displaying 1-9 of 9 articles from this issue
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Special Topic : Mechanisms of Trafficking Processes of Ion Channels and Transporters Between The Plasma Membrane and The Intracellular Space
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Takuto Fujii, Hideki Sakai2018 Volume 43 Issue 5 Pages 194-198
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSCancer cells generally display glucose metabolic reprograming characterized by an increased rate of aerobic glycolysis even under normoxic conditions (also known as Warburg effect). To achieve the rapid proliferation of cancer cells in hypoxic environment, expression level of facilitative glucose transporter GLUT1 is elevated in several cancer cells including hepatocellular carcinoma. Recently, we found that cardiac glycosides, specific inhibitors of Na+, K+– ATPase, induce GLUT1 endocytosis and dramatically suppress the glucose uptake of human hepatocellular carcinoma cells. In this review, we introduce our recent findings concerning inhibitory mechanism of GLUT1 induced by cardiac glycosides in human cancer cells.View full abstractDownload PDF (808K) -
Kotoku Kawaguchi, Ryo Hatano, Shinji Asano2018 Volume 43 Issue 5 Pages 199-205
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSTubular reabsorption of electrolytes in the kidney is an essential function in regulating fluid balance in the body. Na+–K+–2Cl– cotransporter type 2 (NKCC2) is specifically expressed in luminal cell surface of the thick ascending limb of the loop of Henle and the macula densa. The reabsorption of NKCC2 plays important roles in regulating fluid balance and glomerular filtration rate (GFR). In general, luminal surface expression level of NKCC2 is regulated by intracellular membrane trafficking involving exocytosis and endocytosis. It is well known that exocytosis of NKCC2 is promoted by the cAMP/PKA pathway via some hormone stimulation. On the other hand, the molecular mechanisms of endocytosis of NKCC2 are not clear. In this review, I will discuss the roles of moesin, which was reported as a NKCC2–binding protein, in the regulation of endocytosis of NKCC2 and renal function in vivo by using moesin–null (Msn–/y) mice.View full abstractDownload PDF (916K) -
Naomi Niisato2018 Volume 43 Issue 5 Pages 206-210
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSEpithelial Na+ channel (ENaC)–mediated Na+ reabsorption in the distal tubule and cortical collecting duct has a crucial role for controlling ECF volume and blood pressure. ENaC surface expression in the apical membrane is strongly correlated to the ubiquitination–dependent ENaC degradation by activating Nedd4–2 through p38 inhibition. So far, plasma membrane proteins containing ENaC have been considered to be degraded in the endosome–lysosome system, although several reports suggest that proteasome inhibitors affect ENaC surface expression. On the other hand, misfolded membrane proteins are pulled out of lipid bilayer through a p97 (a AAA+ ATPase)–dependent mechanism in ERAD (endoplasmic reticulum associated degradation) and the pulled out proteins are ubiquitinated and targeted to proteasome for its degradation. In this study, we hypothesized that ENaC might be degraded in the proteasome through a similar mechanism to the “retrotranslocation” in ERAD and obtained results that 1) p97 inhibition induced accumulation of ENaC in the apical membrane when ENaC degradation elevated by a p38 inhibitor, 2) ENaC colocalized with p97 and a composition of proteasome by inducing ENaC degradation with a p38 inhibitor. These observations suggest that ENaC might be pulled out of plasma membrane for targeting to proteasome through a p97–dependent mechanism.View full abstractDownload PDF (766K) -
Yoshinori Marunaka2018 Volume 43 Issue 5 Pages 211-214
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSEpithelial Na+ channels (ENaC) play a crucial role in control of blood pressure by regulating renal Na+ reabsorption. Cleavage of ENaC’s extracellular loop is known to increase the open probability of ENaC. Intracellular trafficking of ENaC is also one of the key regulators of ENaC function, but little information is available on regulation of intracellular ENaC recycling. This study determined the rate constant of intracellular ENaC trafficking by applying a protease inhibitor under hypotonic conditions. We measured the transepithelial Na+ transport as short–circuit currents using a four–state mathematical ENaC trafficking model in renal A6 epithelial cells with application of hypotonicity and aprotinin (a protease inhibitor) blocking protease–induced cleavage of the extracellular loop of γENaC subunit. We found that aprotinin significantly diminished the ENaC insertion rate to the apical membrane by 40%, and the ENaC recycling rate by 81%, diminishing the transepithelial Na+ transport (Cell. Physiol. Biochem., 41, 1865- 1880 (2017)).View full abstractDownload PDF (953K)
Special Topic : Membranous tissue and device succeeding in clinical practice
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Guoping Chen, Naoki Kwazoe2018 Volume 43 Issue 5 Pages 215-223
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSPorous scaffolds play an important role in regenerative medicine to provide necessary space for cell assembly and to control cell functions for regeneration of functional tissues and organs. Biodegradable synthetic polymers such as poly(L–lactic acid) (PLLA) and poly(lactic acid–co–glycolic acid) (PLGA) and naturally derived polymers such as collagen and gelatin have been most frequently used for preparation of biodegradable porous scaffolds. To improve the porous structures of scaffolds, we have developed a method using pre–prepared ice particulates as a porogen material. Free ice particulates can be used to increase pore interconnectivity while embossing ice particulates can be used to make surface pores open and to prepare micropatterned pore structures. The open and interconnected pore structures can facilitate homogenous cell distribution and therefore promote functional tissue regeneration. The micropatterned porous scaffolds can be used to control cell orientation and to promote cell bundle formation. We have also developed a hybridization method to combine the advantages of both biodegradable synthetic polymers and naturally derived polymers. The hybrid scaffolds have high mechanical strength, easy handling, good water wettability and cell interaction. The polymeric porous scaffolds have been used for regeneration of cartilage, bone, skin, muscle and ligament. This review summarizes these polymeric porous scaffolds prepared by ice particulates and hybridization and their applications for regenerative medicine.View full abstractDownload PDF (1164K)
Special Topic : Membrane Award for Young Scientists (2018)
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Shunsuke Tanaka2018 Volume 43 Issue 5 Pages 224-230
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSMetal organic framework (MOF) has been recognized as a unique molecular sieving material with flexible framework, enabling interesting “gate-opening” functionality. Recently, it is recognized that such structural transition is induced by molecular adsorption and controlling the crystal size and shape is an effective factor for regulating the structural flexibilities and mass transport properties. This review discusses recent progress in MOF membranes and the challenges and opportunities for future membrane separation technology, and provides an overview of seedingfree aqueous synthesis of crystal–size–engineered ZIF–8 MOF membranes.View full abstractDownload PDF (1365K)
Original Contribution
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Takeshi Nagatani, Takaaski Sasaki, Kyoichi Saito2018 Volume 43 Issue 5 Pages 231-237
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL FREE ACCESSAnion–exchange membranes with permselectivity for mono–valent ions were prepared by three step processes: (1)graft polymerization of chloromethylstyrene (CMS) onto an ultrahigh–molecular–weight polyethylene (UHMWPE) film that had previously been irradiated with an electron beam, (2) reaction between N, N, N, N–tetramethyl–1, 6–hexanediamine (TMHDA) and the CMS graft chains via exclusive crosslinking near both sides of the CMS–grafted UHMWPE film, and (3) introduction of trimethylammonium groups into the remaining CMS graft chains by reaction with trimethylamine. The resulting TMHDA–treated anion–exchange membrane and currently used cationexchange membrane, Selemion® CSO, were both installed in an elecrodialyzer to evaluate their chloride ion selectivity, as well as the resulting brine concentration in the concentrating chamber. Crosslinking of the CMS graft chain with TMHDA and the subsequent introduction of a trimethylammonium group onto the CMS–grafted films with a degree of grafting of >50% clearly exhibited the membrane resistance and a chloride-ion permeability that is comparable with that of the currently used anion–exchange membrane, Selemion® ASA. In addition, the prepared membranes with the same membrane resistance as Selemion® ASA produced brine with 5 ～ 10% higher concentrations than ASA membrane.View full abstractDownload PDF (1049K) -
Hirohito Yamazaki, Yuma Yamamoto, Shiho Hamahara, Tomoya Masuda, Izumi ...2018 Volume 43 Issue 5 Pages 238-245
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL FREE ACCESSIn this study, we focused on acetylated–cyclodextrins (AcCD) as a microporous material to improve the performance of cellulose acetate (CA) membrane. Separation membranes, CA/AcCD, were prepared by adding AcCD to CA up to 50 wt%. Permeability coefficients (P) and ideal separation factor of CA/AcCD were determined by the vacuum time-lag method at 2 atm and 35 ℃ for He, H2, O2, N2, CH4 and CO2 gases. CA/AcCD was obtained as a transparent membrane with a thickness of 14 ～ 47 μm. Permeability coefficients of CA/AcCD was high compared to CA membrane, especially for methane having the largest kinetic diameter among the measured gases. Gas permeability was investigated using AcCD closed the pores with molecular inclusion, and it was found that the gas did not permeate the micropore of CD contained in the membrane. Thus, it was considered that the increase in the P values by the addition of AcCD was caused by the increase in the diffusivity coefficients due to the expansion of the gap between the polymer chains.View full abstractDownload PDF (1171K)
Products Spotlight
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Takahiro Kawakatsu, Kazuki Ishii2018 Volume 43 Issue 5 Pages 246-249
Published: 2018
Released on J-STAGE: October 02, 2018
JOURNAL RESTRICTED ACCESSKurita’s RO chemical lineup is presented. The lineup includes chemicals for coagulation pretreatment, slime control, foulant dispersion, cleaning and rejuvenation. Unique chemicals of Kurita help the RO membrane performance to be highly maintained, for example, KURIVERTER ® BP–201, IK–110, MC–119, KURIDYNE ® M–141, MP–800, and KURIVERTER® RC-200, 300, 400.View full abstractDownload PDF (918K)
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