Heian Jogakuin University

www.heian.ac.jp
Osaka, Japan

Heian Jogakuin University also known at St. Agnes' University, is a private women's college with campuses in Kyoto, Kyoto and Takatsuki, Osaka in Japan. The university's foundation history can be traced through the establishment of St. Agnes' School to 1875. The university received its official charter as an accredited four year university in 2000. The university is an affiliated educational institution of the Nippon Sei Ko Kai, the province of the Anglican Communion in Japan. Wikipedia.

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Hosogi S.,Kyoto Prefectural University of Medicine | Hosogi S.,Heian Jogakuin University | Kusuzaki K.,Heian Jogakuin University | Kusuzaki K.,Kyoto Kujo Hospital | And 6 more authors.
Journal of Cellular and Molecular Medicine | Year: 2014

The purpose of the present study was to clarify roles of cytosolic chloride ion (Cl-) in regulation of lysosomal acidification [intra-lysosomal pH (pHlys)] and autophagy function in human gastric cancer cell line (MKN28). The MKN28 cells cultured under a low Cl- condition elevated pHlys and reduced the intra-lysosomal Cl- concentration ([Cl-]lys) via reduction of cytosolic Cl- concentration ([Cl-]c), showing abnormal accumulation of LC3II and p62 participating in autophagy function (dysfunction of autophagy) accompanied by inhibition of cell proliferation via G0/G1 arrest without induction of apoptosis. We also studied effects of direct modification of H+ transport on lysosomal acidification and autophagy. Application of bafilomycin A1 (an inhibitor of V-type H+-ATPase) or ethyl isopropyl amiloride [EIPA; an inhibitor of Na+/H+ exchanger (NHE)] elevated pHlys and decreased [Cl-]lys associated with inhibition of cell proliferation via induction of G0/G1 arrest similar to the culture under a low Cl- condition. However, unlike low Cl- condition, application of the compound, bafilomycin A1 or EIPA, induced apoptosis associated with increases in caspase 3 and 9 without large reduction in [Cl-]c compared with low Cl- condition. These observations suggest that the lowered [Cl-]c primarily causes dysfunction of autophagy without apoptosis via dysfunction of lysosome induced by disturbance of intra-lysosomal acidification. This is the first study showing that cytosolic Cl- is a key factor of lysosome acidification and autophagy. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.


Hosogi S.,Kyoto Prefectural University of Medicine | Miyazaki H.,Kyoto Prefectural University of Medicine | Nakajima K.-I.,Kyoto Prefectural University of Medicine | Ashihara E.,Kyoto Prefectural University of Medicine | And 6 more authors.
Cellular Physiology and Biochemistry | Year: 2012

Background/Aims: Tumor cells produce a large amount of acidic metabolites due to their high metabolic condition. However, cytosolic pH (pHc) of tumor cells is identical to or even slightly higher than that of normal cells. To maintain pHc at a normal or higher level, tumor cells would have to have higher expression and/or activity of H+ transporting systems than normal cells. The purpose of the present study was to identify effects of ethyl-isopropyl amiloride (EIPA, an inhibitor of Na+/H+ exchanger (NHE)) on proliferation of human gastric cancer MKN28 cells. Methods: Effects of EIPA on proliferation, pHc, [Cl-]c and expression of proteins regulating cell cycle and MAPKs were studied in MKN28 expressing NHE exposed to EIPA for 48 h. Results: EIPA suppressed proliferation of MKN28 cells by causing G0/G1 arrest without any signifcant effects on pHc, but associated with reduction of [Cl -]c. Although EIPA alone had no effects on pHc, EIPA co-applied with DIDS (an inhibitor of Cl-/HCO3 - exchangers; i.e., anion exchanger (AE) and Na+-driven Cl-/HCO 3 - exchanger (NDCBE)) reduced pHc, suggesting that DIDS-sensitive Cl-/HCO3 - transporters such as AE and/or NDCBE keep pHc normal by stimulating HCO 3 - uptake coupled with Cl- release under an NHE-inhibited condition. EIPA-induced lowered [Cl-]c up-regulated expression of p21associated with phosphorylation of MAPKs, suppressing proliferation associated with G0/G1 arrest. Conclusions: EIPA suppressed proliferation of MKN28 cells through up-regulation of p21 expression via reduction of [Cl-]c as a result from DIDS-sensitive Cl-/HCO3 - exchanger-mediated compensation for keeping pHc normal under an NHE-inhibited condition. This is the frst study revealing that an NHE inhibitor suppressed the proliferation of cancer cells by reducing [Cl-]c but not pHc. Copyright © 2012 S. Karger AG, Basel.


Niisato N.,Kyoto Prefectural University of Medicine | Niisato N.,Heian Jogakuin University | Ohta M.,Kyoto Prefectural University of Medicine | Eaton D.C.,Emory University | And 2 more authors.
American Journal of Physiology - Renal Physiology | Year: 2012

We investigated a physiological role for ERK, a member of the MAPK family, in the hypotonic stimulation of epithelial Na+ channel (ENaC)-mediated Na+ reabsorption in renal epithelial A6 cells. We show that hypotonic stress causes a major dephosphorylation of ERK following a rapid transient phosphorylation. PD98059 (a MEK inhibitor) increases dephosphorylated ERK and enhances the hypotonic-stress-stimulated Na+ reabsorption. ERK dephosphorylation is mediated by MAPK phosphatase (MKP). Hypotonic stress activates p38, which in turn induces MKP-1 and to a lesser extent MKP-3 mRNA expression. Inhibition of p38 suppresses MKP-1 induction, preventing hypotonic stress from dephosphorylating ERK. Inhibition of MKP-1 and -3 by the inhibitor NSC95397 also suppresses the hypotonicity-induced dephosphorylation of ERK. NSC95397 reduces both β- and γ-ENaC mRNA expression and ENaC-mediated Na+ reabsorption stimulated by hypotonic stress. In contrast, pretreatment with PD98059 significantly enhances mRNA and protein expression of β- and γ-ENaC even under isotonic conditions. However, PD98059 only stimulates Na+ reabsorption in response to hypotonic stress, suggesting that ERK inactivation by itself (i.e., under isotonic conditions) is not sufficient to stimulate Na+ reabsorption, even though ERK inactivation enhances β- and γ-ENaC expression. Based on these results, we conclude that hypotonic stress stimulates Na+ reabsorption through at least two signaling pathways: 1) induction of MKP-1 that suppresses ERK activity and induces β- and γ-ENaC expression, and 2) promotion of translocation of the newly synthesized ENaC to the apical membrane. © 2012 the American Physiological Society.


Nagao H.,Kyoto Prefectural University of Medicine | Nakajima K.-I.,Kyoto Prefectural University of Medicine | Niisato N.,Kyoto Prefectural University of Medicine | Niisato N.,Heian Jogakuin University | And 6 more authors.
Cellular Physiology and Biochemistry | Year: 2012

Potassium chloride cotransporters (KCCs) mediate electroneutrally-coupled transport of K+ and Cl-, and play crucial roles in various cell functions including regulation of cell volume and homeostasis of cellular Cl-content. Four isoforms of KCCs (KCC1, 2, 3, and 4) have been identified. KCC1 is ubiquitously expressed, whereas KCC2 is mainly expressed in neuronal cells of central nervous system. KCC3 is highly expressed in heart, skeletal muscle, kidney, lung and placenta. KCC4 is mainly expressed in epithelial cells. In this study, we investigated roles of KCCs in NGF-induced neurite outgrowth of rat pheochromocytoma PC12 cells. The most abundantly expressed isoform in PC12 cells was KCC1. Inhibition of KCCs using [(dihydronindenyl)oxy] alkanoic acid (DIOA), an inhibitor of KCCs, enhanced the NGF-induced neurite outgrowth of PC12 cells in a dose-dependent manner. Treatment of PC12 cells with NGF significantly decreased mRNA expression of KCC1, whereas other isoforms, KCC2-4, showed no changes in their mRNA expression in response to NGF treatment. Knockdown of KCC1 using small interfering RNA (siRNA) enhanced the NGF-induced neurite outgrowth. These results suggest that KCC1 negatively regulates the NGF-induced neurite outgrowth of PC12 cells. Copyright © 2012 S. Karger AG, Basel.


Nakajima K.-I.,Kyoto Prefectural University of Medicine | Niisato N.,Kyoto Prefectural University of Medicine | Niisato N.,Heian Jogakuin University | Marunaka Y.,Kyoto Prefectural University of Medicine | Marunaka Y.,Heian Jogakuin University
Biomedical Research | Year: 2011

In the present report, we studied if an isoflavone, genistein, enhances the nerve growth factor (NGF)-induced neurite outgrowth of PC12 cells. Application of genistein enhanced the NGFinduced neurite outgrowth. Knockdown of Na +/K +/2Cl - cotransporter isoform 1 (NKCC1) abolished the stimulatory effect of genistein on the neurite outgrowth. These observations indicate that NKCC1 is essential for genistein to stimulate the NGF-induced neurite outgrowth, although genistein had no effect on the protein expression of NKCC1. On the other hand, genistein activates NKCC1 as shown in our previous study. Taken together, these observations indicate that genistein enhanced the NGF-induced neurite outgrowth in PC12 cells via activation of NKCC1.


Hayata H.,Kyoto Prefectural University of Medicine | Miyazaki H.,Kyoto Prefectural University of Medicine | Miyazaki H.,Heian Jogakuin University | Niisato N.,Kyoto Prefectural University of Medicine | And 4 more authors.
Biochemical and Biophysical Research Communications | Year: 2014

Insulin resistance in the skeletal muscle is manifested by diminished insulin-stimulated glucose uptake and is a core factor in the pathogenesis of type 2 diabetes mellitus (DM), but the mechanism causing insulin resistance is still unknown. Our recent study has shown that pH of interstitial fluids was lowered in early developmental stage of insulin resistance in OLETF rats, a model of type 2 DM. Therefore, in the present study, we confirmed effects of the extracellular pH on the insulin signaling pathway in a rat skeletal muscle-derived cell line, L6 cell. The phosphorylation level (activation) of the insulin receptor was significantly diminished in low pH media. The phosphorylation level of Akt, which is a downstream target of the insulin signaling pathway, also decreased in low pH media. Moreover, the insulin binding to its receptor was reduced by lowering extracellular pH, while the expression of insulin receptors on the plasma membrane was not affected by the extracellular pH. Finally, insulin-stimulated 2-deoxyglucose uptake in L6 cells was diminished in low pH media. Our present study suggests that lowered extracellular pH conditions may produce the pathogenesis of insulin resistance in skeletal muscle cells. © 2014 Elsevier Inc. All rights reserved.


Nakajima K.-I.,Kyoto Prefectural University of Medicine | Niisato N.,Kyoto Prefectural University of Medicine | Niisato N.,Heian Jogakuin University | Marunaka Y.,Kyoto Prefectural University of Medicine | Marunaka Y.,Heian Jogakuin University
Biochemical and Biophysical Research Communications | Year: 2012

In growing neurite of neuronal cells, it is suggested that α/β-tubulin heterodimers assemble to form microtubule, and assembly of microtubule promotes neurite elongation. On the other hand, recent studies reveal importance of intracellular Cl- in regulation of various cellular functions such as cell cycle progression, differentiation, cell migration, and elongation of neurite in neuronal cells. In this study, we investigated effects of Cl- on in vitro tubulin polymerization. We found that efficiency of in vitro tubulin polymerization (the number of microtubule) was higher (3 to 5-fold) in Cl--containing solutions than that in Cl--free solutions containing Br- or NO3- On the other hand, GTPase activity of tubulin was lower (2/3-fold) in Cl--containing solutions than that in Cl--free solutions containing Br- or NO3- Efficiency of in vitro tubulin polymerization in solutions containing a non-hydrolyzable analogue of GTP (GpCpp) instead of GTP was much higher than that in the presence of GTP. Effects of replacement of GTP with GpCpp on in vitro tubulin polymerization was weaker in Cl- solutions (10-fold increases) than that in Br- or NO3- solutions (20-fold increases), although the efficiency of in vitro tubulin polymerization in Cl- solutions containing GpCpp was still higher than that in Br- or NO3- solutions containing GpCpp. Our results suggest that a part of stimulatory effects of Cl- on in vitro tubulin polymerization is mediated via an inhibitory effect on GTPase activity of tubulin, although Cl- would also regulate in vitro tubulin polymerization by factors other than an inhibitory effect on GTPase activity. © 2012 Elsevier Inc.


Nakamura K.,Heian Jogakuin University | Fusaoka A.,Ritsumeikan University
Proceedings of the SICE Annual Conference | Year: 2011

In this paper, we introduce a subclass of hybrid automaton called a symmetric hybrid automaton in which the continuous dynamics for each state is given by a transformation (diffeomorphism) from a core dynamics. Since the continuous dynamics is collapsed into the core dynamics in the symmetric hybrid automaton, we can deal with the properties of systems such as stability and reachability in the core dynamics. We focus on the discrete dynamics and the geometric properties, especially Zeno behavior, of a symmetric hybrid automaton. © 2011 SICE.


Nakamura K.,Heian Jogakuin University | Fusaoka A.,Ritsumeikan University
Proceedings of the IEEE International Conference on Control Applications | Year: 2010

In this paper, we introduce an enlargement of a standard hybrid automaton (HA) called a nonstandard hybrid automaton (NHA) which is another model of HA in the domain of *ℝ rather than ℝ. We define two kinds of almost periodic trajectories called the z-*cycle and p-*cycle on NHA, and we discuss a slightly extended Zeno (*Zeno) and a limit cycle in terms of these cycles. Moreover, we classify the ω-limit set of hybrid dynamics into 4 types and present an example of NHA for each type. © 2010 IEEE.


Takechi T.,Heian Jogakuin University | Maekawa Z.-I.,Heian Jogakuin University | Sugimura Y.,Kyoto Institute of Technology
Food Science and Technology Research | Year: 2011

Sericin is a structural polypetide of silk, consisting of a unique composition of amino acids. The use of sericin as an ingredient for salad dressing was evaluated in an o/w emulsion system with rape oil and vinegar. The low-viscosity sericin from white cocoon showed poor emulsifying activity, whereas non-separable dressing with a low peroxide value (POV) could be produced by the addition of high-viscosity sericin. The use of colored sericin, prepared from yellow-green cocoon shell, maintained a relatively low POV in spite of low viscosity and emulsifying activity levels. Total content of flavonol aglycons in yellow-green sericin was quantified after acid hydrolysis, showing that relatively high amounts of quercetin and kaempferol were detected in the colored sericin.

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