145 results on '"Harada, Nagakatsu"'
Search Results
102. Taurine Alters Respiratory Gas Exchange and Nutrient Metabolism in Type 2 Diabetic Rats
- Author
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Harada, Nagakatsu, primary, Ninomiya, Chika, additional, Osako, Yoshie, additional, Morishima, Masaki, additional, Mawatari, Kazuaki, additional, Takahashi, Akira, additional, and Nakaya, Yutaka, additional
- Published
- 2004
- Full Text
- View/download PDF
103. Differentiation phenotypes of pancreatic islet β- and α-cells are closely related with homeotic genes and a group of differentially expressed genes
- Author
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Mizusawa, Noriko, primary, Hasegawa, Tomoko, additional, Ohigashi, Izumi, additional, Tanaka-Kosugi, Chisato, additional, Harada, Nagakatsu, additional, Itakura, Mitsuo, additional, and Yoshimoto, Katsuhiko, additional
- Published
- 2004
- Full Text
- View/download PDF
104. Effect of Sarpogrelate Hydrochloride, A 5-HT2 Blocker, on Insulin Resistance in Otsuka Long-Evans Tokushima Fatty Rats (OLETF rats), A Type 2 Diabetic Rat Model
- Author
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Takishita, Eiko, primary, Takahashi, Akira, additional, Harada, Nagakatsu, additional, Yamato, Masaki, additional, Yoshizumi, Masanori, additional, and Nakaya, Yutaka, additional
- Published
- 2004
- Full Text
- View/download PDF
105. Exercise training improves acetylcholine-induced endothelium-dependent hyperpolarization in type 2 diabetic rats, Otsuka Long-Evans Tokushima fatty rats
- Author
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Minami, Asako, primary, Ishimura, Noriko, additional, Harada, Nagakatsu, additional, Sakamoto, Sadaichi, additional, Niwa, Yasuharu, additional, and Nakaya, Yutaka, additional
- Published
- 2002
- Full Text
- View/download PDF
106. Combination Therapy of Exercise and Angiotensin-Converting Enzyme Inhibitor Markedly Improves Insulin Sensitivities in Hypertensive Patients With Insulin Resistance
- Author
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Kinoshita, Manabu, primary, Nakaya, Yutaka, additional, Harada, Nagakatsu, additional, Takahashi, Akira, additional, Nomura, Masahiro, additional, and Bando, Shigenobu, additional
- Published
- 2002
- Full Text
- View/download PDF
107. Glutamine protects the small intestinal mucosa in anticancer drug-induced rat enteritis model
- Author
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Takechi, Hirokazu, primary, Mawatari, Kazuaki, additional, Harada, Nagakatsu, additional, Nakaya, Yutaka, additional, Asakura, Megumi, additional, Aihara, Mutsumi, additional, Takizawa, Hiromitsu, additional, Goto, Masakazu, additional, Nishino, Takeshi, additional, Minato, Takuya, additional, Furukita, Yoshihito, additional, Yamamoto, Yota, additional, Yuasa, Yasuhiro, additional, Yamai, Hiromichi, additional, Yoshida, Takahiro, additional, Seike, Junichi, additional, and Tangoku, Akira, additional
- Published
- 2000
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- View/download PDF
108. Membrane topology of murine glycerol-3-phosphate acyltransferase 2
- Author
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Nakagawa, Tadahiko, Harada, Nagakatsu, Miyamoto, Aiko, Kawanishi, Yukiko, Yoshida, Masaki, Shono, Masayuki, Mawatari, Kazuaki, Takahashi, Akira, Sakaue, Hiroshi, and Nakaya, Yutaka
- Subjects
- *
ACYLTRANSFERASES , *GLYCERIN , *TRIGLYCERIDES , *EPITOPES , *BIOINFORMATICS , *HYDROPHOBIC surfaces , *TRYPSIN , *BIOLOGICAL membranes - Abstract
Abstract: Glycerol-3-phosphate acyltransferase (GPAT) is a rate-limiting enzyme in mammalian triacylglycerol biosynthesis. GPAT is a target for the treatment of metabolic disorders associated with high lipid accumulation. Although the molecular basis for GPAT1 activation has been investigated extensively, the activation of other isoforms, such as GPAT2, is less well understood. Here the membrane topology of the GPAT2 protein was examined using an epitope-tag-based method. Exogenously expressed GPAT2 protein was present in the membrane fraction of transformed HEK293 cells even in the presence of Na2CO3 (100mM), indicating that GPAT2 is a membrane-bound protein. Trypsin treatment of the membrane fraction degraded the N-terminal (FLAG) and C-terminal (myc-epitope) protein tags of the GPAT2 protein. Bioinformatic analysis of the GPAT2 protein sequence indicated four hydrophobic sequences as potential membrane-spanning regions (TM1–TM4). Immunoblotting of the myc-epitope tag, which was inserted between each TM region of the GPAT2 protein, showed that the amino acid sequence between TM3 and TM4 was protected from trypsin digestion. These results suggest that the GPAT2 protein has two transmembrane segments and that the N-terminal and C-terminal regions of this protein face the cytoplasm. These results also suggest that the enzymatically active motifs I–III of the GPAT2 protein face the cytosol, while motif IV is within the membrane. It is expected that the use of this topological model of GPAT2 will be essential in efforts to elucidate the molecular mechanisms of GPAT2 activity in mammalian cells. [Copyright &y& Elsevier]
- Published
- 2012
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- View/download PDF
109. Vibrio parahaemolyticus elevates interferon alpha production in intestinal-like epithelial Caco-2 cells.
- Author
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Xin Lian, Takahashi, Akira, Nakano, Masayuki, Hori, Emiko, Mawatari, Kazuaki, Harada, Nagakatsu, Hosaka, Toshio, and Nakaya, Yutaka
- Subjects
VIBRIO parahaemolyticus ,POLYMERASE chain reaction ,GASTROENTERITIS treatment ,GENETIC regulation ,GENE expression ,GENETIC transcription ,INTERFERONS ,GLYCOPROTEINS ,EPITHELIAL cells ,DISEASES - Abstract
Copyright of Canadian Journal of Microbiology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2007
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110. Haemolysin produced by Vibrio mimicus activates two Cl– secretory pathways in cultured intestinal-like Caco-2 cells.
- Author
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Takahashi, Akira, Miyoshi, Shin-ichi, Takata, Noriko, Nakano, Masayuki, Hamamoto, Akiko, Mawatari, Kazuaki, Harada, Nagakatsu, Shinoda, Sumio, and Nakaya, Yutaka
- Subjects
CELLS ,DIARRHEA ,EXCRETION ,GLANDS ,INTESTINAL diseases ,BIOLOGICAL transport - Abstract
Haemolysin (VMH) is a virulent factor produced by Vibrio mimicus, a human pathogen that causes diarrhoea. As intestinal epithelial cells are the primary targets of haemolysin, we investigated its effects on ion transport in human colonic epithelial Caco-2 cells. VMH increased the cellular short circuit current (Isc), used to estimated ion fluxes, and
125 I efflux of the cells. The VMH-induced increases in Isc and125 I efflux were suppressed by depleting Ca2+ from the medium or by pretreating the cells with BAPTA-AM or by Rp-adenosin 3′,5′-cyclic monophosphorothioate triethylammonium salt (Rp-cAMPS). The Cl– channel inhibitors 4,4′-disothiocyanatostibene-2,2′-disulfonic acid (DIDS), glybenclamide, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) suppressed the VMH-induced increases in Isc and125 I efflux. Moreover, VMH increased the intracellular concentrations of Ca2+ and cAMP. Thus, VMH stimulates Caco-2 cells to secrete Cl– by activating both Ca2+ -dependent and cAMP-dependent Cl– secretion mechanisms. VMH forms ion-permeable pores in the lipid bilayer that are non-selectively permeable to small ions. However, the ion permeability of these pores was not inhibited by glybenclamide and DIDS, and VMH did not change the cell membrane potential. These observations indicate that the pores formed on the cell membrane by VMH are unlikely to be involved in VMH-induced Cl– secretion. Notably, VMH stimulated fluid accumulation in the iliac loop test that was fully suppressed by a combination of DIDS and glybenclamide. Thus, Ca2+ -dependent and cAMP-dependent Cl– secretion may be important therapeutic targets with regard to the diarrhoea that is induced by Vibrio mimicus. [ABSTRACT FROM AUTHOR]- Published
- 2007
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111. Effect of TRB3 on Insulin and Nutrient-stimulated Hepatic p70 56 Kinase Activity.
- Author
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Matsushima, Rie, Harada, Nagakatsu, Webster, Nicholas J. G., Tsutsumi, Yasuo M., and Nakaya, Yutaka
- Subjects
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INSULIN , *PROTEIN synthesis , *LIVER , *INSULIN resistance , *CELL culture , *RAPAMYCIN , *LABORATORY mice - Abstract
Insulin and nutrients activate hepatic p70 S6 kinase (S6K1) to regulate protein synthesis. Paradoxically, activation of S6K1 also leads to the development of insulin resistance. In this study, we investigated the effect of TRB3, which acts as an endogenous inhibitor of Akt, on S6K1 activity in vitro and in vivo. In cultured cells, overexpression of TRB3 completely inhibited insulin- stimulated S6K1 activation by mammalian target of rapamycin, whereas knockdown of endogenous TRB3 increased both basal and insulin-stimulated activity. In C57BL/6 mice, adenoviral overexpression of TRB3 inhibited insulin-stimulated activation of hepatic S6K1. In contrast, overexpression of TRB3 did not inhibit nutrient-stimulated S6K1 activity. We also investigated the effect of starvation, feeding, or insulin treatment on TRB3 levels and S6K1 activity in the liver of C57BL/6 and db/db mice. Both insulin and feeding activate S6K1 in db/db mice, but only insulin activates in the C57BL/6 strain, TRB3 levels were 3.5-fold higher in db/db mice than C57BL/6 mice and were unresponsive to feeding or insulin, whereas both treatments reduced TRB3 in C57BL16 mice. Akt was activated by insulin alone in the C57BL/6 strain and but not in db/db mice. Both insulin and feeding activated mammalian target of rapamycin similarly in these mice; however, feeding was unable to activate the downstream target S6K1 in C57BL/6 mice. These results suggest that the nutrient excess in the hyperphagic, hyperinsuilnemic db/db mouse primes the hepatocyte to respond to nutrients resulting in elevated S6K1 activity. The combination of elevated TRB3 and constitutive S6K1 activity results in decreased insulin signaling via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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112. Aeromonas sobria hemolysin causes diarrhea by increasing secretion of HCO3 −.
- Author
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Takahashi, Akira, Nakano, Masayuki, Okamoto, Keinosuke, Fujii, Yoshio, Mawatari, Kazuaki, Harada, Nagakatsu, and Nakaya, Yutaka
- Subjects
DIARRHEA ,AEROMONAS ,MICROBIAL virulence ,ANIONS ,EPITHELIAL cells ,INTESTINES ,CARBONIC anhydrase ,ARTERIES ,VEINS ,ENZYME inhibitors - Abstract
Aeromonas sobria hemolysin (ASH) is one of the major virulence factors produced by A. sobria, a causative agent of diarrhea in humans. We investigated the effects of ASH on anion transport in human colonic epithelial cells. ASH increased short circuit currents across the intestinal epithelia, which were suppressed by anion channel antagonists, such as carbonic anhydrase inhibitors, and by the removal of external HCO
3 − . Iliac fluid accumulation was also inhibited by carbonic anhydrase inhibitors. The results suggest that ASH activates HCO3 − secretion, whose level correlates with the severity of diarrhea. [ABSTRACT FROM AUTHOR]- Published
- 2006
- Full Text
- View/download PDF
113. A pore-forming toxin produced by Aeromonas sobria activates cAMP-dependent Cl− secretory pathways to cause diarrhea
- Author
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Tanoue, Naomi, Takahashi, Akira, Okamoto, Keinosuke, Fujii, Yoshio, Taketani, Yutaka, Harada, Nagakatsu, Nakano, Masayuki, and Nakaya, Yutaka
- Subjects
INTESTINAL diseases ,BIOLOGICAL transport ,EPITHELIAL cells ,DIARRHEA ,CYCLIC adenylic acid - Abstract
Abstract: Aeromonas sobria hemolysin (ASH) is one of the major virulence factors produced by A. sobria, a human pathogen that causes diarrhea. We investigated the effects of ASH on Cl
− transport in human colonic epithelial cells. ASH increased short-circuit currents (Isc) and125 I efflux from Caco-2 cells, indicating ASH activate Cl− secretion. Additions of inhibitors of cyclic AMP dependent Cl− channels, glybenclamide and NPPB suppressed the Isc and125 I efflux increases induced by ASH. And ASH increased the intracellular cyclic AMP concentration. Moreover, ASH stimulated fluid accumulation in the iliac loop test, and glybenclamide and NPPB suppressed this fluid accumulation. Thus, cAMP-dependent Cl− secretory pathway could be related with diarrhea induced by A. sobria. [Copyright &y& Elsevier]- Published
- 2005
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- View/download PDF
114. Taurine Alters Respiratory Gas Exchange and Nutrient Metabolism in Type 2 Diabetic Rats**.
- Author
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Harada, Nagakatsu, Ninomiya, Chika, Osako, Yoshie, Morishima, Masaki, Mawatari, Kazuaki, Takahashi, Akira, and Nakaya, Yutaka
- Published
- 2004
- Full Text
- View/download PDF
115. Effect of Sarpogrelate Hydrochloride, A 5-HT2Blocker, on Insulin Resistance in Otsuka Long-Evans Tokushima Fatty Rats (OLETF rats), A Type 2 Diabetic Rat Model
- Author
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Takishita, Eiko, Takahashi, Akira, Harada, Nagakatsu, Yamato, Masaki, Yoshizumi, Masanori, and Nakaya, Yutaka
- Abstract
5-hydroxytryptamine (5-HT) is closely related to pathogenesis of angiopathy in type 2 diabetes. Acute and chronic effects of sarpogrelate hydrochloride (sarpogrelate), a 5-HT2blocker, on glucose tolerance and insulin resistance were examined. Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes, were randomly assigned to 2 groups; those with 30 mg/kg BW/d sarpogrelate treatment of 4 weeks (HTB group) and without (control group). The glucose infusion rate was significantly increased in the HTB group compared with the control group. The blood glucose levels after oral glucose tolerance test and levels of plasma insulin and lipids were significantly lower in the HTB group than in the control group. To investigate mechanism of the improvement by sarpogrelate, acute effect of 5-HT and its blocking effect by sarpogrelate on blood levels of glucose were examined in 25-week-old Sprague-Dawley rats. Blood glucose levels were significantly increased by administration of 5-HT. This increase was reversed by pretreatment of sarpogrelate. A plasma adrenaline level also rose significantly by injection of the 5-HT and was prevented by pretreatment of sarpogrelate. These results indicate that sarpogrelate improves insulin resistance in type 2 diabetic rats.
- Published
- 2004
116. Reducing Effect of Feeding Powdered Nacre of Pinctada maxima on the Visceral Fat of Rats.
- Author
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Shono, Masayuki, Shimizu, Ichiro, Aoyagi, Eriko, Taniguchi, Tatsuya, Takenaka, Hidetaka, Ishikawa, Momoko, Urata, Mari, Sannomiya, Katsutaka, Tamaki, Katsuyoshi, Harada, Nagakatsu, Nakaya, Yutaka, and Takayama, Tetsuji
- Subjects
PINCTADA ,PEARL oysters ,TRIGLYCERIDES ,WEIGHT loss ,ADIPOSE tissues ,METABOLIC syndrome ,MEDICAL sciences - Abstract
The article studies how feeding the powdered nacre of Pinctada maxima caused a reduction in the levels of blood triglycerides, visceral fat amount and body weight in rats. It includes an in-depth analysis of the role of the accumulation of abdominal fat complicated by high blood triglycerides as a risk factor for metabolic syndromes, as well as a discussion on the issues' implications for the medical sciences.
- Published
- 2008
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117. Reducing Effect of Feeding Powdered Nacre of Pinctada maximaon the Visceral Fat of Rats
- Author
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SHONO, Masayuki, SHIMIZU, Ichiro, AOYAGI, Eriko, TANIGUCHI, Tatsuya, TAKENAKA, Hidetaka, ISHIKAWA, Momoko, URATA, Mari, SANNOMIYA, Katsutaka, TAMAKI, Katsuyoshi, HARADA, Nagakatsu, NAKAYA, Yutaka, and TAKAYAMA, Tetsuji
- Abstract
An abdominal fat accumulation complicated by high blood triglycerides is regarded as a risk factor of metabolic syndrome. Feeding powdered nacre, mother of pearl, from Pinctada maxima, resulted in reduced body weight, visceral fat amount, and blood triglyceride level without influencing the food intake, body length, or amount of muscular tissue, suggesting that nacre powder specifically could decrease visceral fat.
- Published
- 2008
- Full Text
- View/download PDF
118. Endothelin-1(1–31) levels are increased in atherosclerotic lesions of the thoracic aorta of hypercholesterolemic hamsters
- Author
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Mawatari, Kazuaki, Kakui, Sae, Harada, Nagakatsu, Ohnishi, Takamasa, Niwa, Yasuharu, Okada, Kazuko, Takahashi, Akira, Izumi, Keisuke, and Nakaya, Yutaka
- Subjects
- *
AMINO acids , *ARBITRATION & award , *MEDIATION , *DIET - Abstract
Objective: The novel vaso-constricting 31-amino acid-length endothelin-1 [ET-1(1–31)] is selectively produced by human mast cell chymase via its action on big ET-1. However, the pathological role of ET-1(1–31) in atherosclerosis remains unclear. The aim of this study was to clarify vasoconstrictive response and expression of ET-1(1–31) in atherosclerotic aorta. Methods and results: Syrian golden hamster, was used for preparing the atherosclerotic models by the administration of a high cholesterol diet (HC), treatment with the nitric oxide synthase inhibitor (Nω-nitro-l-arginine methylester, l-NAME) alone, or both (HC and l-NAME) for 40 weeks. Early atherosclerosis was observed in the case of HC or l-NAME alone treatments respectively and severe atherosclerosis was observed in the case of combined HC and l-NAME treatment. Vasoconstriction induced by ET-1(1–31) was not altered by the atherosclerotic changes, but the expression pattern of ET-1(1–31) was different at each stage of the atherosclerotic aorta. ET-1(1–31) was observed rarely in normal aortas or in early atherosclerotic lesions, but ET-1(1–31) expression was dramatically increased in aortic neointima and adventitia in a state of atherosclerosis with severe inflammation. Conclusion: ET-1(1–31) might play in a role of promoting atherosclerosis, and especially be involved in inflammatory mediation during the progression of atherosclerosis. [Copyright &y& Elsevier]
- Published
- 2004
- Full Text
- View/download PDF
119. Aeromonas sobria hemolysin causes diarrhea by increasing secretion of HCO3 −.
- Author
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Takahashi, Akira, Nakano, Masayuki, Okamoto, Keinosuke, Fujii, Yoshio, Mawatari, Kazuaki, Harada, Nagakatsu, and Nakaya, Yutaka
- Subjects
- *
DIARRHEA , *AEROMONAS , *MICROBIAL virulence , *ANIONS , *EPITHELIAL cells , *INTESTINES , *CARBONIC anhydrase , *ARTERIES , *VEINS , *ENZYME inhibitors - Abstract
Aeromonas sobria hemolysin (ASH) is one of the major virulence factors produced by A. sobria, a causative agent of diarrhea in humans. We investigated the effects of ASH on anion transport in human colonic epithelial cells. ASH increased short circuit currents across the intestinal epithelia, which were suppressed by anion channel antagonists, such as carbonic anhydrase inhibitors, and by the removal of external HCO3−. Iliac fluid accumulation was also inhibited by carbonic anhydrase inhibitors. The results suggest that ASH activates HCO3− secretion, whose level correlates with the severity of diarrhea. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
120. A pore-forming toxin produced by Aeromonas sobria activates Ca2+ dependent Cl− secretion
- Author
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Takahashi, Akira, Tanoue, Naomi, Nakano, Masayuki, Hamamoto, Akiko, Okamoto, Keinosuke, Fujii, Yoshio, Harada, Nagakatsu, and Nakaya, Yutaka
- Subjects
- *
BIOLOGICAL transport , *INTESTINAL diseases , *ELECTRIC circuit breakers , *ELECTRIC currents - Abstract
Abstract: Bacteria produce many types of hemolysin that induce diarrhea by mechanisms that are not completely understood. Aeromonas sobria hemolysin (ASH) is a major virulence factor produced by A. sobria, a human pathogen that causes diarrhea. Since epithelial cells in the intestine are the primary targets of hemolysin, we investigated the effects of ASH on ion transport in human colonic epithelial (Caco-2) cells. ASH increased short-circuit currents (Isc) in a dose-dependent manner, and it also activated a 125I efflux from Caco-2 cells. ASH-induced Isc increases and 125I efflux activations were both suppressed by low Ca2+ levels in the extracellular solution or by pretreatment with the Ca2+ chlelator BAPTA-AM. Intracellular Ca2+ levels were increased by ASH in a biphasic fashion characterized by a rapid sharp increase (peak 1) followed by a sustained low plateau (peak 2). ASH-induced peak 1 was inhibited by pretreatment with pertussis toxin, indicating that Ca2+ was mobilized from intracellular stores, and peak 2 was induced by an influx of extracellular Ca2+. Peak 2 but not peak 1 was related to Cl− secretion. These results indicate that ASH activates Ca2+-dependent Cl− secretion. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
121. 2-Deoxy-D-Glucose Downregulates Fatty Acid Synthase Gene Expression Via an Endoplasmic Reticulum Stress-Dependent Pathway in HeLa Cells.
- Author
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Harada N, Yoshikatsu A, Yamamoto H, and Nakaya Y
- Abstract
Fatty acid synthase (FASN) catalyzes the rate-limiting step of cellular lipogenesis. FASN expression is upregulated in various types of cancer cells, implying that FASN is a potential target for cancer therapy. 2-Deoxy-D-glucose (2-DG) specifically targets cancer cells by inhibiting glycolysis and glucose metabolism, resulting in multiple anticancer effects. However, whether the effects of 2-DG involve lipogenic metabolism remains to be elucidated. We investigated the effect of 2-DG administration on FASN expression in HeLa human cervical cancer cells. 2-DG treatment for 24 h decreased FASN mRNA and protein levels and suppressed the activity of an exogenous rat Fasn promoter. The use of a chemical activator or inhibitors or of a mammalian expression plasmid showed that neither AMPK nor the Sp1 transcription factor is responsible for the inhibitory effect of 2-DG on FASN expression. Administration of thapsigargin, an endoplasmic reticulum (ER) stress inducer, or 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF), a site 1 protease inhibitor, mimicked the inhibitory effect of 2-DG on FASN expression. 2-DG did not further decrease FASN expression in the presence of thapsigargin or AEBSF. Site 1 protease mediates activation of ATF6, an ER stress mediator, as well as sterol regulatory element-binding protein 1 (SREBP1), a robust transcription factor for FASN. Administration of 2-DG or thapsigargin for 24 h suppressed activation of ATF6 and SREBP1, as did AEBSF. We speculated that these effects of 2-DG or thapsigargin are due to feedback inhibition via increased GRP78 expression following ER stress. Supporting this, exogenous overexpression of GRP78 in HeLa cells suppressed SREBP1 activation and Fasn promoter activity. These results suggest that 2-DG suppresses FASN expression via an ER stress-dependent pathway, providing new insight into the molecular basis of FASN regulation in cancer., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2024
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122. Identification of protease serine S1 family member 53 as a mitochondrial protein in murine islet beta cells.
- Author
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Mizusawa N, Harada N, Iwata T, Ohigashi I, Itakura M, and Yoshimoto K
- Subjects
- Animals, Glucose, Insulin, Mice, Insulin-Secreting Cells, Islets of Langerhans, Mitochondrial Proteins genetics, Serine Proteases genetics
- Abstract
The aim of this study was to identify genes that are specifically expressed in pancreatic islet β-cells (hereafter referred to as β-cells). Large-scale complementary DNA-sequencing analysis was performed for 3,429 expressed sequence tags derived from murine MIN6 β-cells, through homology comparisons using the GenBank database. Three individual ESTs were found to code for protease serine S1 family member 53 ( Prss53 ). Prss53 mRNA is processed into both a short and long form, which encode 482 and 552 amino acids, respectively. Transient overexpression of myc-tagged Prss53 in COS-7 cells showed that Prss53 was strongly associated with the luminal surfaces of organellar membranes and that it underwent signal peptide cleavage and N-glycosylation. Immunoelectron microscopy and western blotting revealed that Prss53 localized to mitochondria in MIN6 cells. Short hairpin RNA-mediated Prss53 knockdown resulted in Ppargc1a downregulation and Ucp2 and Glut2 upregulation. JC-1 staining revealed that the mitochondria were depolarized in Prss53 -knockdown MIN6 cells; however, no change was observed in glucose-stimulated insulin secretion. Our results suggest that mitochondrial Prss53 expression plays an important role in maintaining the health of β-cells.
- Published
- 2022
- Full Text
- View/download PDF
123. Long-chain monounsaturated fatty acids improve endothelial function with altering microbial flora.
- Author
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Tsutsumi R, Yamasaki Y, Takeo J, Miyahara H, Sebe M, Bando M, Tanba Y, Mishima Y, Takeji K, Ueshima N, Kuroda M, Masumoto S, Harada N, Fukuda D, Yoshimoto R, Tsutsumi YM, Aihara KI, Sata M, and Sakaue H
- Subjects
- Animals, Biomarkers, Blood Glucose, Butter, Dietary Fats, Double-Blind Method, Fatty Acids, Monounsaturated chemistry, Female, Fish Oils analysis, Humans, Lipids blood, Male, Mice, Mice, Knockout, ApoE, Olive Oil, Young Adult, Endothelium, Vascular drug effects, Fatty Acids, Monounsaturated pharmacology, Fish Oils pharmacology, Gastrointestinal Microbiome drug effects
- Abstract
Fish oil-derived long-chain monounsaturated fatty acids (LCMUFAs) with a carbon chain length longer than 18 units ameliorate cardiovascular risk in mice. In this study, we investigated whether LCMUFAs could improve endothelial functions in mice and humans. In a double-blind, randomized, placebo-controlled, parallel-group, multi-center study, healthy subjects were randomly assigned to either an LCMUFA oil (saury oil) or a control oil (olive and tuna oils) group. Sixty subjects were enrolled and administrated each oil for 4 weeks. For the animal study, ApoE
-/- mice were fed a Western diet supplemented with 3% of either gadoleic acid (C20:1) or cetoleic acid (C22:1) for 12 weeks. Participants from the LCMUFA group showed improvements in endothelial function and a lower trimethylamine-N-oxide level, which is a predictor of coronary artery disease. C20:1 and C22:1 oils significantly improved atherosclerotic lesions and plasma levels of several inflammatory cytokines, including IL-6 and TNF-α. These beneficial effects were consistent with an improvement in the gut microbiota environment, as evident from the decreased ratio of Firmicutes and/ or Bacteroidetes, increase in the abundance of Akkermansia, and upregulation of short-chain fatty acid (SCFA)-induced glucagon-like peptide-1 (GLP-1) expression and serum GLP-1 level. These data suggest that LCMUFAs alter the microbiota environment that stimulate the production of SCFAs, resulting in the induction of GLP-1 secretion. Fish oil-derived long-chain monounsaturated fatty acids might thus help to protect against cardiovascular disease., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)- Published
- 2021
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124. Differential regulation of Actn2 and Actn3 expression during unfolded protein response in C2C12 myotubes.
- Author
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Harada N, Gotoda Y, Hatakeyama A, Nakagawa T, Miyatake Y, Kuroda M, Masumoto S, Tsutsumi R, Nakaya Y, and Sakaue H
- Subjects
- Actinin genetics, Actinin metabolism, Animals, Computational Biology methods, Humans, Mice, Muscle Fibers, Skeletal cytology, Transfection, Actinin biosynthesis, Muscle Fibers, Skeletal metabolism, Unfolded Protein Response genetics
- Abstract
ACTN2 and ACTN3 encode sarcomeric α-actinin-2 and α-actinin-3 proteins, respectively, that constitute the Z-line in mammalian skeletal muscle fibers. In human ACTN3, a nonsense mutation at codon 577 that encodes arginine (R) produces the R577X polymorphism. Individuals having a homozygous 577XX genotype do not produce α-actinin-3 protein. The 577XX genotype reportedly occurs in sprint and power athletes in frequency lower than in the normal population, suggesting that α-actinin-3 deficiency diminishes fast-type muscle function. Among humans who carry 577R alleles, varying ACTN3 expression levels under certain conditions can have diverse effects on atheletic and muscle performance. However, the factors that regulate ACTN3 expression are unclear. Here we investigated whether the unfolded protein response (UPR) under endoplasmic reticulum (ER) stress regulates expression of Actn3 and its isoform Actn2 in mouse C2C12 myotubes. Among UPR-related transcription factors, XBP1 upregulated Actn2, whereas XBP1, ATF4 and ATF6 downregulated Actn3 promoter activity. Chemical induction of ER stress increased Actn2 mRNA levels, but decreased those for Actn3. ER stress also decreased α-actinin-3 protein levels, whereas levels of α-actinin-2 were unchanged. The intracellular composition of muscle contraction-related proteins was altered under ER stress, in that expression of parvalbumin (a fast-twitch muscle-specific protein) and troponin I type 1 (skeletal, slow) was suppressed. siRNA-induced suppression of Actn3 mimicked the inhibitory effect of ER stress on parvalbumin levels. Thus, endogenous expression levels of α-actinin-3 can be altered by ER stress, which may modulate muscle performance and athletic aptitudes, particularly in humans who carry ACTN3 577R alleles.
- Published
- 2020
- Full Text
- View/download PDF
125. Sterol regulatory element binding protein 1 trans-activates 25-hydroxy vitamin D 3 24-hydroxylase gene expression in renal proximal tubular cells.
- Author
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Kagawa T, Kozai M, Masuda M, Harada N, Nakahashi O, Tajiri M, Yoshikawa R, Nakao M, Takei Y, Iwano M, Takeda E, Taketani Y, and Yamamoto H
- Subjects
- Animals, Base Sequence, Cell Line, Humans, Mice, Promoter Regions, Genetic, Protein Binding, RNA, Messenger genetics, RNA, Messenger metabolism, Transcription, Genetic, Gene Expression Regulation, Enzymologic, Kidney Tubules, Proximal cytology, Kidney Tubules, Proximal metabolism, Sterol Regulatory Element Binding Protein 1 metabolism, Transcriptional Activation genetics, Vitamin D3 24-Hydroxylase genetics
- Abstract
The physiological activity of the steroid derived hormone vitamin D is regulated by several enzymatic steps. Both 25-hydroxy vitamin D
3 1α-hydroxylase (CYP27B1) and 25-hydroxyvitamin D3 24-hydroxylase (CYP24A1) modulate blood levels of 1,25-dihydroxyvitamin D3 , an activated form of vitamin D. We previously demonstrated that CYP27B1 expression was trans-activated by sterol regulatory element binding protein 1 (SREBP1), although whether SREBP1 also regulates CYP24A1 transcription was unclear. Here we investigated the ability of SREBP1 to affect CYP24A1 transcription. In a luciferase reporter assay, mouse and human CYP24A1 promoter activity was strongly activated by SREBP1 in opossum kidney proximal tubular cells (OK-P). Three putative SREs (pSREs) were found in the mouse Cyp24a1 gene promoter and the SREBP1 protein showed specific binding to the pSRE1 element in EMSAs. Site-directed mutagenesis of the pSRE1 element strongly decreased SREBP1-mediated Cyp24a1 gene transcription. Moreover, siRNA-mediated SREBP1 knock-down repressed CYP24A1 expression in human renal proximal tubular epithelial cells (HKC-8). In animal studies, mice given various doses of thyroid hormone (T3 ) showed dose-dependent reductions in renal Srebp1c and Cyp24a1 mRNA levels. Taken together, our results suggest that SREBP1 trans-activates CYP24A1 expression through SREBP binding elements present in the promoter., (Copyright © 2018 Elsevier Inc. All rights reserved.)- Published
- 2018
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126. Intracerebroventricular injection of ghrelin decreases wheel running activity in rats.
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Miyatake Y, Shiuchi T, Mawatari K, Toda S, Taniguchi Y, Futami A, Sato F, Kuroda M, Sebe M, Tsutsumi R, Harada N, Minokoshi Y, Kitamura T, Gotoh K, Ueno M, Nakaya Y, and Sakaue H
- Subjects
- Animals, Arcuate Nucleus of Hypothalamus drug effects, Arcuate Nucleus of Hypothalamus metabolism, Eating drug effects, Ghrelin administration & dosage, Infusions, Intraventricular, Motor Activity physiology, Neurons drug effects, Neurons metabolism, Rats, Rats, Wistar, Sodium Glutamate administration & dosage, Ghrelin metabolism, Motor Activity drug effects, Physical Conditioning, Animal, Running physiology
- Abstract
There is an increasing interest in elucidating the molecular mechanisms by which voluntary exercise is regulated. In this study, we examined how the central nervous system regulates exercise. We used SPORTS rats, which were established in our laboratory as a highly voluntary murine exercise model. SPORTS rats showed lower levels of serum ghrelin compared with those of the parental line of Wistar rats. Intracerebroventricular and intraperitoneal injection of ghrelin decreased wheel-running activity in SPORTS rats. In addition, daily injection of the ghrelin inhibitor JMV3002 into the lateral ventricles of Wistar rats increased wheel-running activity. Co-administration of obestatin inhibited ghrelin-induced increases in food intake but did not inhibit ghrelin-induced suppression of voluntary exercise in rats. Growth hormone secretagogue receptor (GHSR) in the hypothalamus and hippocampus of SPORTS rats was not difference that in control rats. We created an arcuate nucleus destruction model by administering monosodium glutamate (MSG) to neonatal SPORTS rats. Injection of ghrelin into MSG-treated rats decreased voluntary exercise but did not increase food intake, suggesting that wheel-running activity is not controlled by the arcuate nucleus neurons that regulate feeding. These results provide new insights into the mechanism by which ghrelin regulates voluntary activity independent of arcuate nucleus neurons., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2017
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127. C-terminal region of GADD34 regulates eIF2α dephosphorylation and cell proliferation in CHO-K1 cells.
- Author
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Otsuka R, Harada N, Aoki S, Shirai K, Nishitsuji K, Nozaki A, Hatakeyama A, Shono M, Mizusawa N, Yoshimoto K, Nakaya Y, Kitahata H, and Sakaue H
- Subjects
- Animals, CHO Cells, Cell Cycle Proteins genetics, Cell Line, Codon, Nonsense genetics, Cricetinae, Cricetulus, Endoplasmic Reticulum Stress physiology, Enzyme Activation, Glycogen Synthase Kinase 3 beta, Phosphorylation, Wnt Signaling Pathway genetics, Cell Proliferation genetics, Cyclin-Dependent Kinase Inhibitor p21 biosynthesis, Eukaryotic Initiation Factor-2 metabolism, Glycogen Synthase Kinase 3 metabolism, Protein Phosphatase 1 genetics, Protein Phosphatase 1 metabolism
- Abstract
GADD34 is a member of a growth arrest and DNA damage (GADD)-inducible gene family. Here, we established a novel Chinese hamster ovary (CHO)-K1-derived cell line, CHO-K1-G34M, which carries a nonsense mutation (termed the Q525X mutation) in the GADD34 gene. The Q525X mutant protein lacks the C-terminal 66 amino acids required for GADD34 to bind to and activate protein phosphatase 1 (PP1). We investigated the effects of GADD34 with or without the Q525X mutation on the phosphorylation status of PP1 target proteins, including the α subunit of eukaryotic initiation factor 2 (eIF2α) and glycogen synthase kinase 3β (GSK3β). CHO-K1-G34M cells had higher levels of eIF2α phosphorylation compared to the control CHO-K1-normal cells both in the presence and absence of endoplasmic reticulum stress. Overexpression of the wild-type GADD34 protein in CHO-K1-normal cells largely reduced eIF2α phosphorylation, while overexpression of the Q525X mutant did not produce similar reductions. Meanwhile, neither wild type nor Q525X mutation of GADD34 affected the GSK3β phosphorylation status. GADD34 also did not affect the canonical Wnt signaling pathway downstream of GSK3β. Cell proliferation rates were higher, while expression levels of the cyclin-dependent kinase inhibitor p21 were lower in CHO-K1-G34M cells compared to the CHO-K1-normal cells. The GADD34 Q525X mutant had a reduced ability to inhibit cell proliferation and enhance p21 expression of the CHO-K1-normal cells compared to the wild-type GADD34 protein. These results suggest that the GADD34 protein C-terminal plays important roles in regulating not only eIF2α dephosphorylation but also cell proliferation in CHO-K1 cells.
- Published
- 2016
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128. Islet infiltration, cytokine expression and beta cell death in the NOD mouse, BB rat, Komeda rat, LEW.1AR1-iddm rat and humans with type 1 diabetes.
- Author
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Jörns A, Arndt T, Meyer zu Vilsendorf A, Klempnauer J, Wedekind D, Hedrich HJ, Marselli L, Marchetti P, Harada N, Nakaya Y, Wang GS, Scott FW, Gysemans C, Mathieu C, and Lenzen S
- Subjects
- Animals, B-Lymphocytes immunology, Diabetes Mellitus, Type 1 immunology, Gene Expression Regulation, Humans, Immunohistochemistry, Insulin-Secreting Cells immunology, Insulin-Secreting Cells metabolism, Interferon-gamma metabolism, Mice, Mice, Inbred NOD, Rats, Rats, Inbred BB, Rats, Inbred Lew, Real-Time Polymerase Chain Reaction, Tumor Necrosis Factor-alpha metabolism, Apoptosis immunology, B-Lymphocytes pathology, Cytokines metabolism, Diabetes Mellitus, Experimental metabolism, Diabetes Mellitus, Experimental pathology, Diabetes Mellitus, Type 1 metabolism, Diabetes Mellitus, Type 1 pathology, Insulin-Secreting Cells pathology
- Abstract
Aims/hypothesis: Research on the pathogenesis of type 1 diabetes relies heavily on good animal models. The aim of this work was to study the translational value of animal models of type 1 diabetes to the human situation., Methods: We compared the four major animal models of spontaneous type 1 diabetes, namely the NOD mouse, BioBreeding (BB) rat, Komeda rat and LEW.1AR1-iddm rat, by examining the immunohistochemistry and in situ RT-PCR of immune cell infiltrate and cytokine pattern in pancreatic islets, and by comparing findings with human data., Results: After type 1 diabetes manifestation CD8(+) T cells, CD68(+) macrophages and CD4(+) T cells were observed as the main immune cell types with declining frequency, in infiltrated islets of all diabetic pancreases. IL-1β and TNF-α were the main proinflammatory cytokines in the immune cell infiltrate in NOD mice, BB rats and LEW.1AR1-iddm rats, as well as in humans. The Komeda rat was the exception, with IFN-γ and TNF-α being the main cytokines. In addition, IL-17 and IL-6 and the anti-inflammatory cytokines IL-4, IL-10 and IL-13 were found in some infiltrating immune cells. Apoptotic as well as proliferating beta cells were observed in infiltrated islets. In healthy pancreases no proinflammatory cytokine expression was observed., Conclusions/interpretation: With the exception of the Komeda rat, the animal models mirror very well the situation in humans with type 1 diabetes. Thus animal models of type 1 diabetes can provide meaningful information on the disease processes in the pancreas of patients with type 1 diabetes.
- Published
- 2014
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129. Albumin-normalized serum zinc: a clinically useful parameter for detecting taste impairment in patients undergoing dialysis.
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Tsutsumi R, Ohashi K, Tsutsumi YM, Horikawa YT, Minakuchi J, Minami S, Harada N, Sakaue H, Sakai T, and Nakaya Y
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Humans, Kidney Failure, Chronic blood, Kidney Failure, Chronic therapy, Male, Middle Aged, Serum Albumin metabolism, Taste Disorders etiology, Renal Dialysis adverse effects, Serum Albumin analysis, Taste Disorders blood, Zinc blood
- Abstract
Patients with renal failure often experience decreased serum zinc that remains uncorrected after dialysis. A complication of this depletion is taste impairment, which can detrimentally influence diet and nutrition. However, because more than half of all serum zinc is bound to albumin, we hypothesized that normalizing serum zinc to albumin levels may be associated with taste impairment. A total of 65 patients undergoing dialysis but not receiving supplementary zinc and 120 control patients not undergoing dialysis (60 malnourished patients and 60 healthy controls) were tested for their receptiveness to saltiness using various salt concentrations. Patients' total protein and albumin levels were measured, and linear regressions were extrapolated between serum zinc levels and total protein or albumin. Patients undergoing dialysis had significantly lower levels of total serum zinc compared with control patients. However, uncorrected zinc levels were not correlated with taste impairment. Normalizing zinc levels against total protein or albumin resulted in extrapolated equations that revealed a significant correlation with taste impairment. Our data suggest a statistical correlation between zinc and albumin in both healthy subjects and patients undergoing maintenance hemodialysis, or protein-energy malnutrition without hemodialysis, allowing for a quantitative measure for taste impairment., (© 2013.)
- Published
- 2014
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130. Thyroid hormones decrease plasma 1α,25-dihydroxyvitamin D levels through transcriptional repression of the renal 25-hydroxyvitamin D3 1α-hydroxylase gene (CYP27B1).
- Author
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Kozai M, Yamamoto H, Ishiguro M, Harada N, Masuda M, Kagawa T, Takei Y, Otani A, Nakahashi O, Ikeda S, Taketani Y, Takeyama K, Kato S, and Takeda E
- Subjects
- Animals, Enzyme Repression, Humans, Kidney Tubules, Proximal drug effects, Mice, RNA, Messenger metabolism, Response Elements drug effects, Thyroid Hormones metabolism, Transcription, Genetic drug effects, Triiodothyronine pharmacology, 25-Hydroxyvitamin D3 1-alpha-Hydroxylase biosynthesis, Calcitriol blood, Kidney enzymology
- Abstract
The primary determinant of circulating 1α,25-dihydroxyvitamin D (1,25[OH](2)D) levels is the activity of 25-hydroxyvitamin D-1α-hydroxylase (cytochrome P450 27B1 [CYP27B1]) in the kidney. Hyperthyroid patients have been reported to have low levels of plasma 1,25(OH)(2)D. However, the detailed mechanism of thyroid hormone action on vitamin D metabolism is still poorly understood. The present study determined whether renal CYP27B1 gene expression was negatively regulated by thyroid hormones. T(3)-induced hyperthyroid mice showed marked decreases in plasma 1,25(OH)(2)D levels and in renal expression of CYP27B1 mRNA but no changes in plasma concentrations of calcium, PTH, or fibroblast growth factor-23. In addition, we observed that T(3) administration significantly decreased plasma 1,25(OH)(2)D and renal CYP27B1 mRNA levels that were increased by low-calcium or low-phosphorus diets and induced hypocalcemia in mice fed a low-calcium diet. Promoter analysis revealed that T(3) decreases the basal transcriptional activity of the CYP27B1 gene through thyroid hormone receptors (TRα and TRβ1) and the retinoid X receptor α (RXRα) in renal proximal tubular cells. Interestingly, we identified an everted repeat negative thyroid hormone response element (1α-nTRE) overlapping the sterol regulatory element (1α-SRE) and the TATA-box -50 to -20 base pairs from the human CYP27B1 gene transcription start site. Finally, we established that CYP27B1 gene transcription is positively regulated by SRE-binding proteins and that a T(3)-bound TRβ1/RXRα heterodimer inhibits SRE-binding protein-1c-induced transcriptional activity through the 1α-nTRE. These results suggest that transcriptional repression of the CYP27B1 gene by T(3)-bound TRs/RXRα, acting through the 1α-nTRE, results in decreased renal CYP27B1 expression and plasma 1,25(OH)(2)D levels.
- Published
- 2013
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131. Decline in anthropometric evaluation predicts a poor prognosis in geriatric patients.
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Tsutsumi R, Tsutsumi YM, Horikawa YT, Takehisa Y, Hosaka T, Harada N, Sakai T, and Nakaya Y
- Subjects
- Aged, Aged, 80 and over, Analysis of Variance, Anti-Bacterial Agents, Biomarkers, Female, Follow-Up Studies, Geriatric Assessment statistics & numerical data, Humans, Hypoalbuminemia blood, Hypoalbuminemia epidemiology, Japan epidemiology, Length of Stay statistics & numerical data, Male, Malnutrition blood, Nutrition Assessment, Nutrition Surveys statistics & numerical data, Nutritional Status, Predictive Value of Tests, Pressure Ulcer epidemiology, Prevalence, Prognosis, Prospective Studies, Risk Factors, Serum Albumin, Severity of Illness Index, Survival Analysis, Anthropometry methods, Geriatric Assessment methods, Malnutrition epidemiology, Nutrition Surveys methods
- Abstract
Objective: Malnutrition is frequent in the geriatric population and is often undetected and untreated. Although we often use serum albumin as a nutritional marker, it has limitations in elderly patients in terms of predicting diseases and infections. Anthropometric measurements are not commonly used, despite their simple, easy, and effective characteristics. We evaluated the associations between anthropometric measurements with other nutritional factors and examined its relationship with mortality, decubitus ulcer, length of hospital stay and antibiotic usage., Research Methods and Procedures: We enrolled 223 patients, performed anthropometric measurements and then followed them for a mean of 24 months., Results: Patients with hypoalbuminemia but with normal body measurements tended to increase serum albumin levels over the next 24 months and had more favorable outcomes including being discharged. Patients with normal albumin but decreased body measurements resulted in a progressive drop in serum albumin and had a higher mortality rate. Additionally, patients with hypoalbuminemia had higher antibiotic usage than patients without hypoalbuminemia. Decreases in anthropometric measurements were related to mortality, length of hospital stay, and decubitus ulcer., Conclusions: Anthropometric measurements are easily obtained and closely associated with mortality, decubitus ulcer, and length of hospital stay. Anthropometric measurements used in conjunction with serum albumin are more predictive of patient outcome then serum albumin alone.
- Published
- 2012
132. Severe catabolic state after an overnight fast in patients with chronic renal failure.
- Author
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Nakaya Y, Shimohata T, Haraguchi S, Nakao T, Minaguchi J, Sumitani H, Harada N, and Sakaue H
- Subjects
- Aged, Carbon Dioxide metabolism, Dietary Carbohydrates pharmacology, Dietary Carbohydrates therapeutic use, Female, Humans, Lipid Metabolism, Male, Middle Aged, Proteins metabolism, Creatinine blood, Energy Metabolism, Fasting physiology, Kidney Failure, Chronic metabolism, Oxygen Consumption physiology
- Abstract
Objective: Starvation causes more rapid development of a catabolic state in patients with liver cirrhosis than in normal subjects. Because the kidneys have a gluconeogenic activity similar to that of the liver, we tested whether patients with chronic renal failure develop a catabolic state after an overnight fast., Methods: The effect of an overnight fast on diurnal changes in respiratory quotient (RQ) was studied in 12 normal subjects and 12 patients with stable chronic renal failure. Changes in RQ in the early morning after an overnight fast were also studied in 27 patients with chronic renal failure not on dialysis. We also examined the effect on RQ of consuming a light snack in the evening before the measurements., Results: The RQ before breakfast, but not at other times, was significantly lower in patients with renal failure than in normal subjects (0.824 ± 0.051 versus 0.868 ± 0.038, P < 0.05). This indicated that patients with renal failure had higher fat use and developed a catabolic state early in the morning. The RQ before breakfast showed significant inverse correlations with creatinine levels (r = -0.604, P < 0.001). Supplementation with a carbohydrate-rich snack in the evening resulted in a significant increase of 0.07 ± 0.04 (P < 0.05) in mean RQ in the early morning. This suggested that a late evening snack is useful for improving the catabolic state of patients with renal failure., Conclusion: Starvation involving an overnight fast facilitates catabolism of visceral and muscle proteins in renal failure. This suggests that nutritional management of renal failure should focus not only on the contents of a meal, but also on the timing of the meal., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
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133. Vibrio parahaemolyticus infection induces modulation of IL-8 secretion through dual pathway via VP1680 in Caco-2 cells.
- Author
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Shimohata T, Nakano M, Lian X, Shigeyama T, Iba H, Hamamoto A, Yoshida M, Harada N, Yamamoto H, Yamato M, Mawatari K, Tamaki T, Nakaya Y, and Takahashi A
- Subjects
- Caco-2 Cells, Humans, Phosphorylation, Interleukin-8 metabolism, Mitogen-Activated Protein Kinases metabolism, Signal Transduction, Vibrio parahaemolyticus immunology, Vibrio parahaemolyticus pathogenicity, Viral Proteins immunology, Virulence Factors immunology
- Abstract
Background: Vibrio parahaemolyticus causes acute gastroenteritis and inflammations in humans. A variety of pathogenic bacteria can stimulate mitogen-activated protein kinases (MAPKs) in host cells. Phosphorylation of MAPKs leads to production of interleukin (IL)- 8 and subsequently causes inflammations. Thus, MAPK cascades were strong candidates for the main signaling pathway of V. parahaemolyticus-induced acute inflammation., Methods: To determine whether the signaling pathway on V. parahaemolyticus infection induces inflammation, we analyzed the secretion level of IL-8 and phosphorylation of MAPKs by use of intestinal epithelial Caco-2 cells., Results: V. parahaemolyticus infection of Caco-2 cells activated extracellular signal-regulated kinase (ERK) 1/2 and p38 MAPK signal pathways, leading to IL-8 secretion, whereas MAPK inhibitors, UO126 or SB203580, suppressed IL-8 secretion. A strain carrying a deletion of VP1680, a type three secretion system 1 (T3SS1) effector protein, failed to activate phosphorylation of ERK1/2 and p38 MAPK and secretion of IL-8. ERK1/2 pathway inhibitor, UO126, failed IL-8 promoter activity, whereas p38 MAPK inhibitor, SB203580, decreased the stabilization of IL-8 messenger RNA following V. parahaemolyticus infection., Conclusions: We showed that V. parahaemolyticus infection of Caco-2 cells results in the secretion of IL-8, and that VP1680 plays a pivotal role in manipulating host cell signaling and is responsible for triggering IL-8 secretion.
- Published
- 2011
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134. Beta-adrenergic-AMPK pathway phosphorylates acetyl-CoA carboxylase in a high-epinephrine rat model, SPORTS.
- Author
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Hattori A, Mawatari K, Tsuzuki S, Yoshioka E, Toda S, Yoshida M, Yasui S, Furukawa H, Morishima M, Ono K, Ohnishi T, Nakano M, Harada N, Takahashi A, and Nakaya Y
- Subjects
- Adrenergic beta-Antagonists pharmacology, Analysis of Variance, Animals, Blood Glucose metabolism, Blotting, Western, Body Weight drug effects, Body Weight physiology, Eating, Enzyme-Linked Immunosorbent Assay, Glucose Tolerance Test, Insulin blood, Intra-Abdominal Fat drug effects, Male, Obesity metabolism, Phosphorylation drug effects, Propranolol pharmacology, Pyrazoles pharmacology, Pyrimidines pharmacology, Rats, Up-Regulation drug effects, AMP-Activated Protein Kinases metabolism, Acetyl-CoA Carboxylase metabolism, Epinephrine metabolism, Intra-Abdominal Fat metabolism, Receptors, Adrenergic, beta metabolism
- Abstract
We established a new animal model called SPORTS (Spontaneously-Running Tokushima-Shikoku) rats, which show high-epinephrine (Epi) levels. Recent reports show that Epi activates adenosine monophosphate (AMP)-activated protein kinase (AMPK) in adipocytes. Acetyl-CoA carboxylase (ACC) is the rate-limiting enzyme in fatty acid synthesis, and the enzymatic activity is suppressed when its Ser-79 is phosphorylated by AMPK. The aim of this study was to investigate the in vivo effect of Epi on ACC and abdominal visceral fat accumulation. We divided both 6-week male control and SPORTS rats into two groups, which were fed either normal diet or high fat and sucrose (HFS) diet for 16 weeks. At the end of diet treatment, retroperitoneal fat was collected for western blotting and histological analysis. Food intake was not different among the groups, but SPORTS rats showed significantly lower weight gain than control rats in both diet groups. After 10 weeks of diet treatment, glucose tolerance tests (GTTs) revealed that SPORTS rats had increased insulin sensitivity. Furthermore, SPORTS rats had lower quantities of both abdominal fat and plasma triglyceride (TG). In abdominal fat, elevated ACC Ser-79 phosphorylation was observed in SPORTS rats and suppressed by an antagonist of beta-adrenergic receptor (AR), propranolol, or an inhibitor of AMPK, Compound C. From these results, high level of Epi induced ACC phosphorylation mediated through beta-AR and AMPK signaling pathways in abdominal visceral fat of SPORTS rats, which may contribute to reduce abdominal visceral fat accumulation and increase insulin sensitivity. Our results suggest that beta-AR-regulated ACC activity would be a target for treating lifestyle-related diseases, such as obesity.
- Published
- 2010
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135. L-DOPA inhibits nitric oxide-dependent vasorelaxation via production of reactive oxygen species in rat aorta.
- Author
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Yinhua, Harada N, Mawatari K, Yasui S, Segawa H, Takahashi A, Oshita S, and Nakaya Y
- Subjects
- Animals, Aorta, Thoracic drug effects, Aorta, Thoracic physiology, Cells, Cultured, Cyclic GMP physiology, Drug Synergism, Endothelium, Vascular drug effects, Endothelium, Vascular physiology, Guanylate Cyclase physiology, In Vitro Techniques, Levodopa administration & dosage, Male, Myocytes, Smooth Muscle drug effects, Myocytes, Smooth Muscle physiology, Phenylephrine administration & dosage, Rats, Rats, Wistar, Reactive Oxygen Species metabolism, Receptors, Cytoplasmic and Nuclear physiology, Soluble Guanylyl Cyclase, Vasodilation physiology, Levodopa pharmacology, Nitric Oxide physiology, Vasodilation drug effects
- Abstract
Objectives: To clarify the underlying mechanisms of L-DOPA induced vasoconstriction in rat aorta., Methods: The effect of L-DOPA on phenylephrine-induced contractile force of blood vessels was examined in vitro using rat aortic ring preparations by isometric tension experiment. Involvement of nitric oxide (NO) in the effect of L-DOPA on vascular smooth muscle was studied by using N(omega)-Nitro-L-arginine (L-NNA), Sodium nitroprusside (SNP) in endothelium-intact and endothelium-denuded aortic rings., Results: L-DOPA potentiated alpha-adrenergic receptor- and depolarization-induced vascular contraction and inhibited acetylcholine-induced vasorelaxation. This effect was diminished by pretreatment of the aortic rings with L-NNA, an inhibitor of NO synthesis, or by removing the endothelium from the ring preparations. In endothelium-denuded rings, L-DOPA inhibited exogenous NO-dependent but not cGMP-mediated vasorelaxation. Increases in cGMP levels in response to an NO donor were attenuated by L-DOPA in cultured rat aortic smooth muscle cells. L-DOPA could not contract rings (without endothelium) pretreated with 3-(5'-hydroxymethyl- 2'-furyl)-1-benzyl indazole (YC-1), an activator of guanylyl cyclase, but SOD (150 U/ml) pretreatment of rings with endothelium inhibited contraction by L-DOPA., Conclusions: These results suggest that L-DOPA inhibits nitric-dependent vasorelaxation on vascular smooth muscle cells via production of reactive oxygen species.
- Published
- 2009
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136. Hypocaloric high-protein diet improves fatty liver and hypertriglyceridemia in sucrose-fed obese rats via two pathways.
- Author
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Uebanso T, Taketani Y, Fukaya M, Sato K, Takei Y, Sato T, Sawada N, Amo K, Harada N, Arai H, Yamamoto H, and Takeda E
- Subjects
- Animals, Blood Glucose metabolism, Cells, Cultured, Diet, Reducing methods, Dietary Proteins pharmacology, Fasting blood, Fasting metabolism, Fatty Liver etiology, Feeding Behavior drug effects, Feeding Behavior physiology, Hypertriglyceridemia etiology, Male, Obesity chemically induced, Obesity complications, Rats, Rats, Sprague-Dawley, Signal Transduction drug effects, Sucrose, Caloric Restriction, Dietary Proteins therapeutic use, Fatty Liver diet therapy, Hypertriglyceridemia diet therapy, Obesity diet therapy
- Abstract
The mechanism by which replacement of some dietary carbohydrates with protein during weight loss favors lipid metabolism remains obscure. In this study, we investigated the effect of an energy-restricted, high-protein/low-carbohydrate diet on lipid metabolism in obese rats. High-sucrose-induced obese rats were assigned randomly to one of two energy-restricted dietary interventions: a carbohydrate-based control diet (CD) or a high-protein diet (HPD). Lean rats of the same age were assigned as normal control. There was significantly greater improvement in fatty liver and hypertriglyceridemia with the HPD diet relative to the CD diet. Expression of genes regulated by fibroblast growth factor-21 (FGF21) and involved in liver lipolysis and lipid utilitization, such as lipase and acyl-CoA oxidase, increased in obese rats fed the HPD. Furthermore, there was an inverse correlation between levels of FGF21 gene expression (regulated by glucagon/insulin balance) and increased triglyceride concentrations in liver from obese rats. Expression of hepatic stearoyl-CoA desaturase-1 (SCD1), regulated primarily by the dietary carbohydrate, was also markedly reduced in the HPD group (similar to plasma triglyceride levels in fasting animals) relative to the CD group. In conclusion, a hypocaloric high-protein diet improves fatty liver and hypertriglyceridemia effectively relative to a carbohydrate diet. The two cellular pathways at work behind these benefits include stimulation of hepatic lipolysis and lipid utilization mediated by FGF21 and reduction of hepatic VLDL-TG production by SCD1 regulation.
- Published
- 2009
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137. Effect of iron-quercetin complex on reduction of nitrite in in vitro and in vivo systems.
- Author
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Ohnishi H, Iwanaga S, Kawazoe K, Ishizawa K, Orino S, Tomita S, Tsuchiya K, Kanematsu Y, Harada N, Mori K, Tsuchihashi T, Ishikawa Y, and Tamaki T
- Subjects
- Animals, Antioxidants chemistry, Iron chemistry, Male, Nitrates chemistry, Nitrates metabolism, Nitric Oxide chemistry, Nitric Oxide metabolism, Nitrites chemistry, Oxidation-Reduction, Quercetin chemistry, Rats, Rats, Sprague-Dawley, Antioxidants metabolism, Iron metabolism, Nitrites metabolism, Quercetin metabolism
- Abstract
This study investigated whether reducing agents such as quercetin and iron(II) facilitate formation of nitric oxide (NO) gas from orally ingested nitrite in an vivo study. When 3 mg/kg Na (15)NO2 was orally administered to rats with or without iron(II) or quercetin, Hb (15)NO, which is indicative of systemic (15)NO, was detected in the blood, with the maximum blood concentration of Hb (15)NO at 15 min after nitrite or nitrite plus quercetin treatment, whereas after administration of nitrite plus iron(II) or nitrite plus iron(II) and quercetin, the time was shortened to 10 min. Interestingly, iron(II), quercetin, or iron(II) plus quercetin did not affect the total amount of Hb (15)NO generated from orally administered Na (15)NO2. However, the systemic nitrite concentration was significantly decreased in the presence of iron(II) or iron(II) plus quercetin. These results may indicate that iron(II) is critical to the generation of NO gas from nitrite, whereas quercetin contributed little under the in vivo experimental conditions.
- Published
- 2008
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138. NO-1886, a lipoprotein lipase activator, attenuates contraction of rat intestinal ring preparations.
- Author
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Wu Q, Harada N, Nakamura A, Yoshida M, Mawatari K, Hattori A, Li Q, Shimohata T, Yinhua, Lian X, Nakano M, Hosaka T, Takahashi A, and Nakaya Y
- Subjects
- Animals, Calcium physiology, Diabetes Mellitus, Type 2 complications, In Vitro Techniques, Lipoprotein Lipase Activators, Male, Myosin-Light-Chain Kinase physiology, Obesity complications, Rats, Rats, Inbred OLETF, Rats, Wistar, Benzamides pharmacology, Gastrointestinal Motility drug effects, Hypolipidemic Agents pharmacology, Intestinal Diseases etiology, Intestinal Diseases physiopathology, Intestines drug effects, Muscle Contraction drug effects, Muscle, Smooth drug effects, Organophosphorus Compounds pharmacology, Peptides pharmacology
- Abstract
Various intestinal symptoms or diseases are closely associated with intestinal motility, which may be altered by metabolic disturbances associated with diabetes and obesity. It is therefore important that drugs used in the treatment of metabolic disorders should not have any adverse effects on the intestine. In the present study, we examined whether [4-(4-bromo-2-cyano-phenylcarbamoyl)-benzyl]-phosphonic acid diethyl ester (NO-1886), a lipoprotein lipase activator with anti-diabetic and/or anti-obese activity, affects stimulant-induced intestinal contractility. Administration of NO-1886 to intestinal ring preparations of ileum, rectum and colon isolated from Wistar rats attenuated or relaxed contraction induced by a high K+ environment or acetylcholine (ACh). This effect of NO-1886 was dependent on extracellular Ca(2+) and intracellular myosin light chain kinase activity. Our results also showed that ACh-induced colonic contraction was significantly higher in the obese Otsuka Long-Evans Tokushima Fatty (OLETF) than in the non-obese Long-Evans Tokushima Otsuka (LETO) rats. The hypercontractility observed in the colons of OLETF rats occurred concomitantly with an elevation in muscarinic M3 ACh receptor protein levels. Administration of NO-1886 attenuated the obesity-induced hypercontractility of the colonic rings of OLETF rats. Thus, intestinal contractile system would be a novel pharmacological target of the lipoprotein lipase activator NO-1886.
- Published
- 2008
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139. Reactive oxygen species induced by diamide inhibit insulin-induced ATP-sensitive potassium channel activation in cultured vascular smooth muscle cells.
- Author
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Mawatari K, Yasui S, Morizumi R, Hamamoto A, Furukawa H, Koyama K, Hattori A, Yoshioka E, Yoshida M, Nakano M, Teshigawara K, Harada N, Hosaka T, Takahashi A, and Nakaya Y
- Subjects
- Animals, Cells, Cultured, Diamide pharmacology, Enzyme Activation drug effects, Insulin Resistance, Myocytes, Smooth Muscle cytology, Oxidative Stress, Proto-Oncogene Proteins metabolism, Rats, Myocytes, Smooth Muscle metabolism, Potassium Channels metabolism, Reactive Oxygen Species pharmacology, Receptor, Insulin metabolism, Signal Transduction
- Abstract
Both insulin resistance and reactive oxygen species (ROS) have been reported to play essential pathophysiological roles in cardiovascular diseases. However, the mechanistic link between ROS and insulin resistance in the vasculature remains unclear. Recently we have shown that insulin causes KATP channel activation mediated by PI3K in cultured vascular smooth muscle cells (VSMCs). KATP channel in VSMCs is critical in the regulation of vascular tonus. Here we examined the effects of ROS induced by a thol-oxidizing agent, diamide, on the insulin signalling pathway and KATP channel activities in cultured VSMCs (A10 cells). Diamide (100 microM) increased intercellular ROS and extracellular signal-regulated kinases (ERK) activity. Treatment with 100 M diamide suppressed significantly insulin-induced IRS and Akt phosphorylation. In addition to IRS and Akt, diamide inhibited insulin receptor auto-phosphorylation. Patch-clamp study showed that diamide suppressed insulin-induced but did not pinacidil-induced KATP channel activities in A10 cells. From these data, we conclude that ROS inhibit critical insulin signal transduction components including IRS and Akt, and these effects cause down-regulation of insulin's action in the vasculature including KATP channel activation. This study may contribute to our understanding of mechanisms of insulin resistance-associated cardiovascular disease.
- Published
- 2008
140. Bezafibrate improves bacterial lipopolysaccharide-induced dyslipidemia and anorexia in rats.
- Author
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Harada N, Kusuyama A, Morishima M, Okada K, Takahashi A, and Nakaya Y
- Subjects
- Animals, Anorexia chemically induced, Blood Glucose analysis, Blood Proteins analysis, Blotting, Northern, Body Weight, Dyslipidemias chemically induced, Energy Metabolism, Ion Channels genetics, Lipoprotein Lipase genetics, Male, Mitochondrial Proteins genetics, Muscle Proteins analysis, Organ Size, RNA, Messenger genetics, Rats, Rats, Wistar, Uncoupling Protein 3, Anorexia drug therapy, Bezafibrate therapeutic use, Dyslipidemias drug therapy, Hypolipidemic Agents therapeutic use, Lipopolysaccharides pharmacology
- Abstract
Bacterial endotoxin/lipopolysaccharide (LPS)-induced cachexia is characterized by weight loss, anorexia, and a disturbance in lipid metabolism, namely, hypertriacylglycerolemia. The aim of this study in rats with acute endotoxicity induced by an injection of LPS was to investigate whether bezafibrate, a ligand for peroxisome proliferator-activated receptor alpha and a lipoprotein lipase (LPL) activator, improved cachectic conditions, including impaired lipid metabolism. Short-term administration of LPS in the rats resulted in impairment of triacylglycerol clearance in plasma after the intake of fresh cream. In addition, LPS increased whole-body energy expenditure, reduced fasting body weight and caused anorexia in the rats. Bezafibrate treatment resulted in significant improvements in LPS-induced dyslipidemia and anorexia, but had no effect on energy expenditure, respiratory quotient, or fasting body weight in the endotoxic rats. Administration of LPS was also associated with a decrease in the level of messenger RNA (mRNA) expression for LPL in white adipose tissue and skeletal muscle and an increase in the mRNA levels for uncoupling protein 3 in skeletal muscle. Bezafibrate treatment reversed the decline in LPL mRNA levels in white adipose tissue but not in the skeletal muscle tissue of the rats. The enhanced uncoupling protein 3 mRNA level in the endotoxic rats was not affected by bezafibrate treatment. Plasma concentration of leptin was increased by short-term LPS treatment. Bezafibrate decreased the level of plasma leptin significantly without affecting the level of leptin mRNA expression. These results suggest that bezafibrate may be an effective drug not only for impaired triacylglycerol metabolism, but also for anorexia in cachectic states induced by bacterial infections.
- Published
- 2007
- Full Text
- View/download PDF
141. Molecular cloning of a murine glycerol-3-phosphate acyltransferase-like protein 1 (xGPAT1).
- Author
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Harada N, Hara S, Yoshida M, Zenitani T, Mawatari K, Nakano M, Takahashi A, Hosaka T, Yoshimoto K, and Nakaya Y
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, CHO Cells, Cell Line, Chromosomes, Mammalian genetics, Cloning, Molecular, Cricetinae, Cricetulus, Epitopes, Exons genetics, Gene Expression Profiling, Gene Expression Regulation, Enzymologic, Glycerol-3-Phosphate O-Acyltransferase chemistry, Introns genetics, Mice, Mice, Inbred C57BL, Mitochondria enzymology, Molecular Sequence Data, RNA, Messenger genetics, RNA, Messenger metabolism, Sequence Homology, Amino Acid, Glycerol-3-Phosphate O-Acyltransferase genetics
- Abstract
A novel murine glycerol-3-phosphate acyltransferase-like protein 1 (named xGPAT1) has been cloned. The mouse xGPAT1 gene is located on mouse Chromosome 2, spans >19 kb, and consists of at least 23 exons. The protein is 32% identical and 72% similar to mouse mitochondrial GPAT (mtGPAT) on the amino acid level. Sequencing analysis confirmed that xGPAT1 has a 2403-bp open reading frame (ORF) that encodes an 801-amino acid protein with an estimated molecular mass of 89.1 kDa. A hydropathy plot of the deduced xGPAT1 protein showed a high degree of similarity with that of the mtGPAT protein. Using 5'-rapid amplification of cDNA ends, two alternate, untranslated exon 1 (1a and b) isoforms were obtained, generating variants xGPAT1-v1 and xGPAT1-v2. xGPAT1-v1 is expressed in mouse heart, liver, spleen, kidney and murine inner medullary collecting duct 3 (mIMCD3) cells, while xGPAT1-v2 is expressed in mouse liver, spleen, kidney, white and brown adipose tissues and 3T3-L1 pre- and post-adipocytes. xGPAT1 was distributed in the membrane fraction and showed GPAT activity when epitope-tagged xGPAT1 was expressed in Chinese hamster ovary (CHO)-K1 cells.
- Published
- 2007
- Full Text
- View/download PDF
142. Haemolysin produced by Vibrio mimicus activates two Cl- secretory pathways in cultured intestinal-like Caco-2 cells.
- Author
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Takahashi A, Miyoshi S, Takata N, Nakano M, Hamamoto A, Mawatari K, Harada N, Shinoda S, and Nakaya Y
- Subjects
- 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid pharmacology, Animals, Bacterial Proteins isolation & purification, Biological Transport drug effects, Caco-2 Cells, Calcium metabolism, Cyclic AMP metabolism, Egtazic Acid analogs & derivatives, Egtazic Acid pharmacology, Glyburide pharmacology, Hemolysin Proteins isolation & purification, Humans, Intestinal Mucosa metabolism, Intestines drug effects, Intestines pathology, Iodine Radioisotopes metabolism, Membrane Potentials drug effects, Mice, Bacterial Proteins pharmacology, Chlorides metabolism, Hemolysin Proteins pharmacology, Vibrio mimicus metabolism
- Abstract
Haemolysin (VMH) is a virulent factor produced by Vibrio mimicus, a human pathogen that causes diarrhoea. As intestinal epithelial cells are the primary targets of haemolysin, we investigated its effects on ion transport in human colonic epithelial Caco-2 cells. VMH increased the cellular short circuit current (Isc), used to estimated ion fluxes, and 125I efflux of the cells. The VMH-induced increases in Isc and 125I efflux were suppressed by depleting Ca2+ from the medium or by pretreating the cells with BAPTA-AM or by Rp-adenosin 3',5'-cyclic monophosphorothioate triethylammonium salt (Rp-cAMPS). The Cl- channel inhibitors 4,4'-disothiocyanatostibene-2,2'-disulfonic acid (DIDS), glybenclamide, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) suppressed the VMH-induced increases in Isc and 125I efflux. Moreover, VMH increased the intracellular concentrations of Ca2+ and cAMP. Thus, VMH stimulates Caco-2 cells to secrete Cl- by activating both Ca2+ -dependent and cAMP-dependent Cl- secretion mechanisms. VMH forms ion-permeable pores in the lipid bilayer that are non-selectively permeable to small ions. However, the ion permeability of these pores was not inhibited by glybenclamide and DIDS, and VMH did not change the cell membrane potential. These observations indicate that the pores formed on the cell membrane by VMH are unlikely to be involved in VMH-induced Cl- secretion. Notably, VMH stimulated fluid accumulation in the iliac loop test that was fully suppressed by a combination of DIDS and glybenclamide. Thus, Ca2+-dependent and cAMP-dependent Cl- secretion may be important therapeutic targets with regard to the diarrhoea that is induced by Vibrio mimicus.
- Published
- 2007
- Full Text
- View/download PDF
143. A pore-forming toxin produced by Aeromonas sobria activates cAMP-dependent Cl- secretory pathways to cause diarrhea.
- Author
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Tanoue N, Takahashi A, Okamoto K, Fujii Y, Taketani Y, Harada N, Nakano M, and Nakaya Y
- Subjects
- Animals, Caco-2 Cells, Cells, Cultured drug effects, Cells, Cultured metabolism, Chloride Channels metabolism, Diarrhea metabolism, Humans, Intestinal Mucosa metabolism, Mice, Aeromonas chemistry, Bacterial Toxins toxicity, Chlorides metabolism, Cyclic AMP metabolism, Diarrhea microbiology, Hemolysin Proteins toxicity, Intestinal Mucosa drug effects
- Abstract
Aeromonas sobria hemolysin (ASH) is one of the major virulence factors produced by A. sobria, a human pathogen that causes diarrhea. We investigated the effects of ASH on Cl(-) transport in human colonic epithelial cells. ASH increased short-circuit currents (Isc) and (125)I efflux from Caco-2 cells, indicating ASH activate Cl(-) secretion. Additions of inhibitors of cyclic AMP dependent Cl(-) channels, glybenclamide and NPPB suppressed the Isc and (125)I efflux increases induced by ASH. And ASH increased the intracellular cyclic AMP concentration. Moreover, ASH stimulated fluid accumulation in the iliac loop test, and glybenclamide and NPPB suppressed this fluid accumulation. Thus, cAMP-dependent Cl(-) secretory pathway could be related with diarrhea induced by A. sobria.
- Published
- 2005
- Full Text
- View/download PDF
144. Differentiation phenotypes of pancreatic islet beta- and alpha-cells are closely related with homeotic genes and a group of differentially expressed genes.
- Author
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Mizusawa N, Hasegawa T, Ohigashi I, Tanaka-Kosugi C, Harada N, Itakura M, and Yoshimoto K
- Subjects
- Animals, Blotting, Northern, Cell Line, Transformed, Cell Line, Tumor, DNA, Complementary genetics, DNA, Complementary metabolism, Islets of Langerhans cytology, Mice, NIH 3T3 Cells, Oligonucleotide Array Sequence Analysis methods, Phenotype, RNA, Messenger genetics, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction methods, Cell Differentiation genetics, Gene Expression Profiling, Genes, Homeobox genetics, Islets of Langerhans metabolism
- Abstract
To identify the genes that determine differentiation phenotypes, we compared gene expression of pancreatic islet beta- and alpha-cells, which are derived from the common precursor and secrete insulin and glucagon, respectively. The expression levels of homeotic genes including Hox genes known to determine region specificity in the antero-posterior (AP) body axis, tissue-specific homeobox genes, and other 8,734 genes were compared in a beta- and alpha-cell line of MIN6 and alpha TC1.6. The expression of homeotic genes were surveyed with reverse transcription-polymerase chain reaction (RT-PCR) using degenerate primers corresponding to invariant amino acid sequences within the homeodomain and subsequently with specific primers. Expression of Hoxc6, Hoxc9, Hoxc10, Pdx1, Cdx2, Gbx2, Pax4, and Hlxb9 genes in MIN6 was higher than those in alpha TC1.6, while expression of Hoxa2, Hoxa3, Hoxa5, Hoxa6, Hoxa7, Hoxa9, Hoxa10, Hoxa13, Hoxb3, Hoxb5, Hoxb6, Hoxb13, Hoxb8, and Brain4 genes in alpha TC1.6 was higher than those in MIN6. Out of 8,734 mouse genes screened with high-density mouse cDNA microarrays for MIN6- and alpha TC1.6-derived cDNA, 58 and 25 genes were differentially over- and under-expressed in MIN6, respectively. GLUTag, which is derived from a large bowel tumor and expresses the proglucagon gene, showed a comparatively similar expression profile to that of alpha TC1.6 in both homeotic and other genes analyzed in cDNA microarray. Our results are consistent with the interpretation that not only the tissue-specific homeotic genes, but also Hox genes are related to differentiation phenotypes of pancreatic beta- and alpha-cells rather than their regional specification of the body in vertebrates.
- Published
- 2004
- Full Text
- View/download PDF
145. Decreased blood levels of lactic acid and urinary excretion of 3-methylhistidine after exercise by chronic taurine treatment in rats.
- Author
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Manabe S, Kurroda I, Okada K, Morishima M, Okamoto M, Harada N, Takahashi A, Sakai K, and Nakaya Y
- Subjects
- Animals, Blood Glucose analysis, Blood Proteins analysis, Body Weight, Cholesterol blood, Creatinine blood, Cysteine blood, Dietary Supplements, Eating, Fatty Acids, Nonesterified blood, Male, Rats, Rats, Wistar, Triglycerides blood, Lactic Acid blood, Methylhistidines urine, Physical Exertion, Taurine pharmacology
- Abstract
Taurine is reported to increase contractility of skeletal muscle and cardiac myocyte, which can increase exercise performance. The present study aimed to clarify taurine's effect on chronic endurance exercise, especially accumulation of lactic acid (LA), a marker of fatigue and ability of aerobic exercise, and urinary secretion of 3-methylhistidine (3-MH), a marker of muscle breakdown in rats. After exercise blood levels of LA and urinary excretion of 3-MH were significantly increased and this increase was significantly less in those with chronic treatment of taurine. Taurine treatment also significantly decreased fat accumulation and blood levels of cholesterol and triglyceride, which might improve insulin resistance and utilization of fat and glucose. These results indicate taurine treatment is useful for reducing physical fatigue and muscle damage during exercise training in rats, presumably due to antioxidant property and improvement of muscle and cardiac functions by taurine.
- Published
- 2003
- Full Text
- View/download PDF
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