研究者詳細 - 佐藤（沼田）　かお理

TRPM7 is an essential regulator for volume-sensitive outwardly rectifying anion channel

Tomohiro Numata, Kaori Sato-Numata, Meredith C. Hermosura, Yasuo Mori, Yasunobu Okada

Communications Biology ( Springer Science and Business Media LLC ) 4 ( 1 ) 599 2021年12月 [査読有り]

研究論文（学術雑誌）国際共著

<title>Abstract</title>Animal cells can regulate their volume after swelling by the regulatory volume decrease (RVD) mechanism. In epithelial cells, RVD is attained through KCl release mediated via volume-sensitive outwardly rectifying Cl− channels (VSOR) and Ca2+-activated K+ channels. Swelling-induced activation of TRPM7 cation channels leads to Ca2+ influx, thereby stimulating the K+ channels. Here, we examined whether TRPM7 plays any role in VSOR activation. When TRPM7 was knocked down in human HeLa cells or knocked out in chicken DT40 cells, not only TRPM7 activity and RVD efficacy but also VSOR activity were suppressed. Heterologous expression of TRPM7 in TRPM7-deficient DT40 cells rescued both VSOR activity and RVD, accompanied by an increase in the expression of LRRC8A, a core molecule of VSOR. TRPM7 exerts the facilitating action on VSOR activity first by enhancing molecular expression of LRRC8A mRNA through the mediation of steady-state Ca2+ influx and second by stabilizing the plasmalemmal expression of LRRC8A protein through the interaction between LRRC8A and the <italic>C</italic>-terminal domain of TRPM7. Therefore, TRPM7 functions as an essential regulator of VSOR activity and LRRC8A expression.

Cell Death Induction and Protection by Activation of Ubiquitously Expressed Anion/Cation Channels. Part 2: Functional and Molecular Properties of ASOR/PAC Channels and Their Roles in Cell Volume Dysregulation and Acidotoxic Cell Death

Yasunobu Okada, Kaori Sato-Numata, Ravshan Z. Sabirov, Tomohiro Numata

Frontiers in Cell and Developmental Biology 9 702317 2021年07月 [査読有り] [招待有り]

研究論文（学術雑誌）国際共著

For survival and functions of animal cells, cell volume regulation (CVR) is essential. Major hallmarks of necrotic and apoptotic cell death are persistent cell swelling and shrinkage, and thus they are termed the necrotic volume increase (NVI) and the apoptotic volume decrease (AVD), respectively. A number of ubiquitously expressed anion and cation channels play essential roles not only in CVR but also in cell death induction. This series of review articles address the question how cell death is induced or protected with using ubiquitously expressed ion channels such as swelling-activated anion channels, acid-activated anion channels, and several types of TRP cation channels including TRPM2 and TRPM7. In the Part 1, we described the roles of swelling-activated VSOR/VRAC anion channels. Here, the Part 2 focuses on the roles of the acid-sensitive outwardly rectifying (ASOR) anion channel, also called the proton-activated chloride (PAC) anion channel, which is activated by extracellular protons in a manner sharply dependent on ambient temperature. First, we summarize phenotypical properties, the molecular identity, and the three-dimensional structure of ASOR/PAC. Second, we highlight the unique roles of ASOR/PAC in CVR dysfunction and in the induction of or protection from acidotoxic cell death under acidosis and ischemic conditions.

BK Channels Are Activated by Functional Coupling With L-Type Ca²⁺ Channels in Cricket Myocytes

Tomohiro Numata, Kaori Sato-Numata, Masami Yoshino

Frontiers in Insect Science ( Frontiers Media SA ) 1 2021年04月 [査読有り]

研究論文（学術雑誌）国内共著

Large-conductance calcium (Ca2+)-activated potassium (K+) (BK) channel activation is important for feedback control of Ca2+influx and cell excitability during spontaneous muscle contraction. To characterize endogenously expressed BK channels and evaluate the functional relevance of Ca2+sources leading to BK activity, patch-clamp electrophysiology was performed on cricket oviduct myocytes to obtain single-channel recordings. The single-channel conductance of BK channels was 120 pS, with increased activity resulting from membrane depolarization or increased intracellular Ca2+concentration. Extracellular application of tetraethylammonium (TEA) and iberiotoxin (IbTX) suppressed single-channel current amplitude. These results indicate that BK channels are endogenously expressed in cricket oviduct myocytes. Ca2+release from internal Ca2+stores and Ca2+influx via the plasma membrane, which affect BK activity, were investigated. Extracellular Ca2+removal nullified BK activity. Administration of ryanodine and caffeine reduced BK activity. Administration of L-type Ca2+channel activity regulators (Bay K 8644 and nifedipine) increased and decreased BK activity, respectively. Finally, the proximity between the L-type Ca2+channel and BK was investigated. Administration of Bay K 8644 to the microscopic area within the pipette increased BK activity. However, this increase was not observed at a sustained depolarizing potential. These results show that BK channels are endogenously expressed in cricket oviduct myocytes and that BK activity is regulated by L-type Ca2+channel activity and Ca2+release from Ca2+stores. Together, these results show that functional coupling between L-type Ca2+and BK channels may underlie the molecular basis of spontaneous rhythmic contraction.

Vasopressin Neurons Respond to Hyperosmotic Stimulation with Regulatory Volume Increase and Secretory Volume Decrease by Activating Ion Transporters and Ca²⁺ Channels.

Kaori Sato-Numata, Tomohiro Numata, Yoichi Ueta, Yasunobu Okada

Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology 55 ( S1 ) 119 - 134 2021年03月 [査読有り] [招待有り]

研究論文（学術雑誌）国内共著

BACKGROUND/AIMS: Arginine vasopressin (AVP) neurons play an important role for sensing a change in the plasma osmolarity and thereby responding with regulated AVP secretion in order to maintain the body fluid homeostasis. The osmo-sensing processes in magnocellular neurosecretory cells (MNCs) including AVP and oxytocin (OXT) neurons of the hypothalamus were reported to be coupled to sustained osmotic shrinkage or swelling without exhibiting discernible cell volume regulation. Since increasing evidence has shown some important differences in properties between AVP and OXT neurons, osmotic volume responses are to be reexamined with distinguishing these cell types from each other. We previously reported that AVP neurons identified by transgenic expression of enhanced green fluorescence protein (eGFP) possess the ability of regulatory volume decrease (RVD) after hypoosmotic cell swelling. Thus, in the present study, we examined the ability of regulatory volume increase (RVI) after hyperosmotic cell shrinkage in AVP neurons. METHODS: Here, we used eGFP-identified AVP neurons acutely dissociated from AVP-eGFP transgenic rats. We performed single-cell size measurements, cytosolic RT-PCR analysis, AVP secretion measurements, and patch-clamp studies. RESULTS: The AVP neurons were found to respond to a hyperosmotic challenge with physiological cell shrinkage caused by massive secretion of AVP, called a secretory volume decrease (SVD), superimposed onto physical osmotic cell shrinkage, and also to exhibit the ability of RVI coping with osmotic and secretory cell shrinkage. Furthermore, our pharmacological and molecular examinations indicated that AVP secretion and its associated SVD event are triggered by activation of T-type Ca2+ channels, and the RVI event is attained by parallel operation of Na+/H+ exchanger and Cl-/HCO3- anion exchanger. CONCLUSION: Thus, it is concluded that AVP neurons respond to hyperosmotic stimulation with the regulatory volume increase and the secretory volume increase by activating ion transporters and Ca2+ channels, respectively.

DOI PubMed

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潤腸湯に含まれる生薬成分による分泌性細胞縮小作用の検討

沼田朋大, 佐藤(沼田)かお理, 岡田泰伸, 岡田泰伸, 井上隆司

日本生理学雑誌(Web) 82 ( 2 ) 2020年

J-GLOBAL

慢性便秘漢方薬「潤腸湯」の作用機序の解明

沼田朋大, 佐藤(沼田)かお理, 岡田泰伸, 井上隆司

生体機能と創薬シンポジウム要旨集 2018 2018年

J-GLOBAL

慢性便秘薬「潤腸湯」の作用メカニズムの解明

沼田朋大, 佐藤(沼田)かお理, 佐藤(沼田)かお理, 井上隆司

日本生理学雑誌(Web) 80 ( 2 ) 2018年

J-GLOBAL

Anion Channels Involved in Cell Survival-Death Switching.

Y. Okada, K. Sato-Numata, T. Shimizu, H. Sakai, T. Akita, T. Okada

JOURNAL OF GENERAL PHYSIOLOGY ( ROCKEFELLER UNIV PRESS ) 142 ( 2 ) 12A - 13A 2013年08月

Study on the hypoosmolarity sensing mechanism in arginine - vasopressin neurons : Reexamination on the taurine hypothesis

Kaori Sato-Numata, Yoichi Ueta, Yasunobu Okada

JOURNAL OF PHYSIOLOGICAL SCIENCES ( SPRINGER JAPAN KK ) 63 S188 - S188 2013年

研究発表要旨（全国大会，その他学術会議）

学術関係受賞【表示／非表示】

女性研究者支援コンソーシアムあきた賞

2022年12月女性研究者支援コンソーシアムあきたバソプレシンニューロンの容積調節、及び分泌機構の全容解明

受賞者：佐藤　かお理
入澤宏・彩記念若手研究奨励賞

2017年03月日本生理学会 LRRC8 family is involved in volume-sensitive outwardly rectifying anion channel (VSOR) activity but not in acid-sensitive outwardly rectifying anion channel (ASOR) activity

受賞者：佐藤（沼田）かお理
入澤宏・彩記念若手研究奨励賞

2017年03月日本生理学会 LRRC8ファミリーは容積感受性外向整流性アニオンチャネル(VSOR)の活性に関与するが酸感受性外向整流性アニオンチャネル(ASOR)の活性には関与しない

受賞者：佐藤(沼田) かお理
日本生理学会九州奨励賞

2015年10月09日西日本生理学会ニューロン酸感受性外向整流性アニオンチャネル（ASOR）のアシドーシス性脳神経細胞障害に対する低温救済への関与

受賞者：佐藤（沼田）かお理
日本生理学会九州奨励賞

2015年10月西日本生理学会ニューロン酸感受性外向整流性アニオンチャネル（ASOR）のアシドーシス性脳神経細胞障害に対する低温救済への関与

受賞者：佐藤(沼田) かお理

科研費（文科省・学振）獲得実績【表示／非表示】

バソプレシンの分泌調節を担う浸透圧検知性イオンチャネルの同定と機能解析

基盤研究(C)

研究期間: 2021年04月 - 2024年03月代表者: 佐藤（沼田）かお理
バソプレシンニューロン細胞内塩化物イオンの高濃度維持機構とその生理学的意義の解明

特別研究員奨励費

研究期間: 2018年10月 - 2022年03月代表者: 佐藤（沼田）かお理
細胞生存に係る酸感受性アニオンチャネルの生理的役割の解明

基盤研究(C)

研究期間: 2017年04月 - 2020年03月代表者: 佐藤（沼田）かお理
ES細胞の浸透圧応答とAVPニューロンへの再生・分化メカニズムの解明

特別研究員奨励費

研究期間: 2015年04月 - 2019年03月代表者: 佐藤（沼田）かお理
容積感受性アニオンチャネルVSORと新規関連タンパク質LRRC8Aの相互作用機構

挑戦的研究（開拓・萌芽）

研究期間: 2015年04月 - 2017年03月代表者: 岡田泰伸

学会等発表【表示／非表示】

LRRC8Dのヒト上皮細胞における調節性容積減少への役割

佐藤（沼田）かお理, 鈴木太郎, 酒井彩子, 森俊太郎, 岡田泰伸, 沼田朋大

日本生理学会第100回記念大会 (国立京都国際会館) 2023年03月 - 2023年03月日本生理学会第100回記念大会
バソプレシンニューロンは高浸透圧刺激に対して分泌性容積減少（SVD）と調節性容積増加（RVI）という相反性容積応答をする

佐藤（沼田）かお理，沼田朋大，上田陽一，岡田泰伸

第126回日本解剖学会総会・全国学術集会, 第98回日本生理学会大会 2021年03月 - 2021年03月
Ni⁺感受性Ca²⁺チャネルはバソプレシンニューロンの細胞体/樹状突起からのエクソサイトーシス分泌に関与する

佐藤(沼田)かお理，沼田朋大，上田陽一，井上隆司，岡田泰伸

第97回日本生理学会大会 2020年03月 - 2020年03月
Sensitivity of voltage-dependent Ca²⁺ channels in rat AVP neurons to an anthranilic acid derivative

Kaori Sato-Numata，Tomohiro Numata，Yoichi Ueta，Yasunobu Okada

The 9th Federation of Asian and Oceanian Physiological Societies (FAOPS) Congress 2019年03月 - 2019年03月
AVP産生ニューロンからの浸透圧応答性AVP分泌と容積調節メカニズム

佐藤(沼田)かお理

第3回イオンチャネル研究会 2018年07月 - 2018年07月