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Yalta K, Palabıyık O, Gurdogan M, Yetkın E. Hyponatremia and takotsubo syndrome: a review of pathogenetic and clinical implications. Heart Fail Rev 2024; 29:27-44. [PMID: 37698728 DOI: 10.1007/s10741-023-10344-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/01/2023] [Indexed: 09/13/2023]
Abstract
Hyponatremia is a common electrolyte abnormality with important prognostic and therapeutic implications. It might exert detrimental effects on various organ systems including the central nervous system (CNS), bone, and heart along with its potential association with poor quality of life. These adverse effects might be largely mediated through a variety of mechanisms including osmotic stress, dysfunctional transmembrane exchangers, and enhanced oxidative stress.Interestingly, hyponatremia might also have an important association with takotsubo syndrome (TTS) that has been universally considered as a reversible form of cardiomyopathy usually emerging in response to various stressors. In this context, severe hyponatremia was previously reported to serve as a direct trigger of TTS evolution largely through its potential impact on CNS and heart. However, pathogenetic and clinical implications of hyponatremia still need to be thoroughly evaluated in patients with TTS. This paper aims to analyze the clinical features of published cases with TTS primarily triggered by hyponatremia and also aims to discuss the association between hyponatremia and TTS from a broader perspective.
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Affiliation(s)
- Kenan Yalta
- Cardiology Department, School of Medicine, TrakyaUniversity, Balkan Yerleşkesi, 22030, Edirne, Turkey.
| | - Orkide Palabıyık
- Trakya University, Vocational Collage of Health Services, Edirne, Turkey
| | - Muhammet Gurdogan
- Cardiology Department, School of Medicine, TrakyaUniversity, Balkan Yerleşkesi, 22030, Edirne, Turkey
| | - Ertan Yetkın
- Türkiye Hastanesi, Cardiology Department, Istanbul, Turkey
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2
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Singlet Oxygen, Photodynamic Therapy, and Mechanisms of Cancer Cell Death. JOURNAL OF ONCOLOGY 2022; 2022:7211485. [PMID: 35794980 PMCID: PMC9252714 DOI: 10.1155/2022/7211485] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/07/2022] [Accepted: 05/11/2022] [Indexed: 01/06/2023]
Abstract
Photodynamic therapy (PDT) can be developed into an important arsenal against cancer; it is a minimally invasive therapy, which is used in the treatment or/and palliation of a variety of cancers and benign diseases. The removal of cancerous tissue is achieved with the use of photosensitizer and a light source, which excites the photosensitizer. This excitation causes the photosensitizer to generate singlet oxygen and other reactive oxygen species. PDT has been used in several types of cancers including nonmelanoma skin cancer, bladder cancer, esophageal cancer, head and neck cancer, and non-small cell lung cancer (NSCLC). Although it is routinely used in nonmelanoma skin cancer, it has not been widely adopted in other solid cancers due to a lack of clinical data showing the superiority of PDT over other forms of treatment. Singlet oxygen used in PDT can alter the activity of the catalase, which induces immunomodulation through HOCl signaling. The singlet oxygen can induce apoptosis through both the extrinsic and intrinsic pathways. The extrinsic pathway of apoptosis starts with the activation of the Fas receptor by singlet oxygen that leads to activation of the caspase-7 and caspase-3. In the case of the intrinsic pathway, disruption caused by singlet oxygen in the mitochondria membrane leads to the release of cytochrome c, which binds with APAF-1 and procaspase-9, forming a complex, which activates caspase-3. Mechanisms of PDT action can vary according to organelles affected. In the plasma membrane, membrane disruption is caused by the oxidative stress leading to the intake of calcium ions, which causes swelling and rupture of cells due to excess intake of water, whereas disruption of lysosome causes the release of the cathepsins B and D, which cleave Bid into tBid, which changes the mitochondrial outer membrane permeability (MOMP). Oxidative stress causes misfolding of protein in the endoplasmic reticulum. When misfolding exceeds the threshold, it triggers unfolding protein response (UPR), which leads to activation of caspase-9 and caspase-3. Finally, the activation of p38 MAPK works as an alternative pathway for the induction of MOMP.
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Yamada K, Ding WG, Omatsu-Kanbe M, Toyoda F, Tsuji S, Katsura D, Kimura F, Matsuura H, Murakami T. Expression and functional maintenance of volume-regulated anion channels in myometrial smooth muscles of pregnant mice. Exp Anim 2022; 71:123-130. [PMID: 34789619 PMCID: PMC9130036 DOI: 10.1538/expanim.21-0111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 10/13/2021] [Indexed: 11/15/2022] Open
Abstract
Pregnancy causes changes in the uterus, such as increased cell volume and altered water content. However, the mechanisms that protect the structure and maintain the function of uterine smooth muscle cells against these changes during pregnancy have not been clarified. This study focused on the volume-regulated anion channel (VRAC), which opens with cell swelling under low osmotic pressure and releases Cl- ions and various organic osmolytes to resist cell swelling and regulates a wide range of biological processes such as cell death. In this study, myometrial smooth muscle (MSM) tissues and cells (MSMCs) were collected from non-pregnant and pregnant mice. Using western blotting and immunocytochemistry, leucine-rich repeat containing protein 8A (LRRC8A), an essential membrane protein that constitutes part of the VRAC, was determined to be diffused throughout MSMCs including in the cell membrane. Patch-clamp experiments were performed to investigate the electrophysiology of swelling-induced Cl- currents (ICl, swell) mediated by the VRAC. No significant changes between non-pregnancy and pregnancy groups were observed in either the expression density of LRRC8A or the current density of ICl, swell, however the presence of LRRC8A on the cell membrane was significantly increased in the third trimester of pregnancy compared to the non-pregnancy. This study suggests that the VRAC may play a role, such as maintaining cellular homeostasis in the pregnant MSM.
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Affiliation(s)
- Kazutaka Yamada
- Department of Obstetrics and Gynecology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga, 520-2192, Japan
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga 520-2192, Japan
| | - Mariko Omatsu-Kanbe
- Department of Physiology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga 520-2192, Japan
| | - Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga 520-2192, Japan
| | - Shunichiro Tsuji
- Department of Obstetrics and Gynecology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga, 520-2192, Japan
| | - Daisuke Katsura
- Department of Obstetrics and Gynecology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga, 520-2192, Japan
| | - Fuminori Kimura
- Department of Obstetrics and Gynecology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga, 520-2192, Japan
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga 520-2192, Japan
| | - Takashi Murakami
- Department of Obstetrics and Gynecology, Shiga University of Medical Science, Setatsukinowa-cho, Otsu-shi, Shiga, 520-2192, Japan
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Abstract
PURPOSE OF REVIEW Total ceramide levels in cardiac tissue relate to cardiac dysfunction in animal models. However, emerging evidence suggests that the fatty acyl chain length of ceramides also impacts their relationship to cardiac function. This review explores evidence regarding the relationship between ceramides and left ventricular dysfunction and heart failure. It further explores possible mechanisms underlying these relationships. RECENT FINDINGS In large, community-based cohorts, a higher ratio of specific plasma ceramides, C16 : 0/C24 : 0, related to worse left ventricular dysfunction. Increased left ventricular mass correlated with plasma C16 : 0/C24 : 0, but this relationship became nonsignificant after adjustment for multiple comparisons. Decreased left atrial function and increased left atrial size also related to C16 : 0/C24 : 0. Furthermore, increased incident heart failure, overall cardiovascular disease (CVD) mortality and all-cause mortality were associated with higher C16 : 0/C24 : 0 (or lower C24 : 0/C16 : 0). Finally, a number of possible biological mechanisms are outlined supporting the link between C16 : 0/C24 : 0 ceramides, ceramide signalling and CVD. SUMMARY High cardiac levels of total ceramides are noted in heart failure. In the plasma, C16 : 0/C24 : 0 ceramides may be a valuable biomarker of preclinical left ventricular dysfunction, remodelling, heart failure and mortality. Continued exploration of the mechanisms underlying these profound relationships may help develop specific lipid modulators to combat cardiac dysfunction and heart failure.
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Affiliation(s)
- Lauren K. Park
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Valene Garr-Barry
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Juan Hong
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - John Heebink
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Rajan Sah
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Linda R. Peterson
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
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Tureckova J, Kamenicka M, Kolenicova D, Filipi T, Hermanova Z, Kriska J, Meszarosova L, Pukajova B, Valihrach L, Androvic P, Zucha D, Chmelova M, Vargova L, Anderova M. Compromised Astrocyte Swelling/Volume Regulation in the Hippocampus of the Triple Transgenic Mouse Model of Alzheimer’s Disease. Front Aging Neurosci 2022; 13:783120. [PMID: 35153718 PMCID: PMC8829436 DOI: 10.3389/fnagi.2021.783120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/27/2021] [Indexed: 11/13/2022] Open
Abstract
In this study, we aimed to disclose the impact of amyloid-β toxicity and tau pathology on astrocyte swelling, their volume recovery and extracellular space (ECS) diffusion parameters, namely volume fraction (α) and tortuosity (λ), in a triple transgenic mouse model of Alzheimer’s disease (3xTg-AD). Astrocyte volume changes, which reflect astrocyte ability to take up ions/neurotransmitters, were quantified during and after exposure to hypo-osmotic stress, or hyperkalemia in acute hippocampal slices, and were correlated with alterations in ECS diffusion parameters. Astrocyte volume and ECS diffusion parameters were monitored during physiological aging (controls) and during AD progression in 3-, 9-, 12- and 18-month-old mice. In the hippocampus of controls α gradually declined with age, while it remained unaffected in 3xTg-AD mice during the entire time course. Moreover, age-related increases in λ occurred much earlier in 3xTg-AD animals than in controls. In 3xTg-AD mice changes in α induced by hypo-osmotic stress or hyperkalemia were comparable to those observed in controls, however, AD progression affected α recovery following exposure to both. Compared to controls, a smaller astrocyte swelling was detected in 3xTg-AD mice only during hyperkalemia. Since we observed a large variance in astrocyte swelling/volume regulation, we divided them into high- (HRA) and low-responding astrocytes (LRA). In response to hyperkalemia, the incidence of LRA was higher in 3xTg-AD mice than in controls, which may also reflect compromised K+ and neurotransmitter uptake. Furthermore, we performed single-cell RT-qPCR to identify possible age-related alterations in astrocytic gene expression profiles. Already in 3-month-old 3xTg-AD mice, we detected a downregulation of genes affecting the ion/neurotransmitter uptake and cell volume regulation, namely genes of glutamate transporters, α2β2 subunit of Na+/K+-ATPase, connexin 30 or Kir4.1 channel. In conclusion, the aged hippocampus of 3xTg-AD mice displays an enlarged ECS volume fraction and an increased number of obstacles, which emerge earlier than in physiological aging. Both these changes may strongly affect intercellular communication and influence astrocyte ionic/neurotransmitter uptake, which becomes impaired during aging and this phenomenon is manifested earlier in 3xTg-AD mice. The increased incidence of astrocytes with limited ability to take up ions/neurotransmitters may further add to a cytotoxic environment.
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Affiliation(s)
- Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Jana Tureckova,
| | - Monika Kamenicka
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Denisa Kolenicova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Tereza Filipi
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Zuzana Hermanova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Lenka Meszarosova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Barbora Pukajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Lukas Valihrach
- Laboratory of Gene Expression, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
| | - Peter Androvic
- Laboratory of Gene Expression, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
| | - Daniel Zucha
- Laboratory of Gene Expression, Institute of Biotechnology, Czech Academy of Sciences, Vestec, Czechia
- Faculty of Chemical Technology, University of Chemistry and Technology, Prague, Czechia
| | - Martina Chmelova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Lydia Vargova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
- Second Faculty of Medicine, Charles University, Prague, Czechia
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The Important Role of Ion Transport System in Cervical Cancer. Int J Mol Sci 2021; 23:ijms23010333. [PMID: 35008759 PMCID: PMC8745646 DOI: 10.3390/ijms23010333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 12/26/2021] [Accepted: 12/27/2021] [Indexed: 12/15/2022] Open
Abstract
Cervical cancer is a significant gynecological cancer and causes cancer-related deaths worldwide. Human papillomavirus (HPV) is implicated in the etiology of cervical malignancy. However, much evidence indicates that HPV infection is a necessary but not sufficient cause in cervical carcinogenesis. Therefore, the cellular pathophysiology of cervical cancer is worthy of study. This review summarizes the recent findings concerning the ion transport processes involved in cell volume regulation and intracellular Ca2+ homeostasis of epithelial cells and how these transport systems are themselves regulated by the tumor microenvironment. For cell volume regulation, we focused on the volume-sensitive Cl− channels and K+-Cl− cotransporter (KCC) family, important regulators for ionic and osmotic homeostasis of epithelial cells. Regarding intracellular Ca2+ homeostasis, the Ca2+ store sensor STIM molecules and plasma membrane Ca2+ channel Orai proteins, the predominant Ca2+ entry mechanism in epithelial cells, are discussed. Furthermore, we evaluate the potential of these membrane ion transport systems as diagnostic biomarkers and pharmacological interventions and highlight the challenges.
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Fibbi B, Marroncini G, Anceschi C, Naldi L, Peri A. Hyponatremia and Oxidative Stress. Antioxidants (Basel) 2021; 10:1768. [PMID: 34829639 PMCID: PMC8614907 DOI: 10.3390/antiox10111768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 12/15/2022] Open
Abstract
Hyponatremia, i.e., the presence of a serum sodium concentration ([Na+]) < 136 mEq/L, is the most frequent electrolyte imbalance in the elderly and in hospitalized patients. Symptoms of acute hyponatremia, whose main target is the central nervous system, are explained by the "osmotic theory" and the neuronal swelling secondary to decreased extracellular osmolality, which determines cerebral oedema. Following the description of neurological and systemic manifestations even in mild and chronic hyponatremia, in the last decade reduced extracellular [Na+] was associated with detrimental effects on cellular homeostasis independently of hypoosmolality. Most of these alterations appeared to be elicited by oxidative stress. In this review, we focus on the role of oxidative stress on both osmolality-dependent and -independent impairment of cell and tissue functions observed in hyponatremic conditions. Furthermore, basic and clinical research suggested that oxidative stress appears to be a common denominator of the degenerative processes related to aging, cancer progression, and hyponatremia. Of note, low [Na+] is able to exacerbate multiple manifestations of senescence and to decrease progression-free and overall survival in oncologic patients.
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Affiliation(s)
- Benedetta Fibbi
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Giada Marroncini
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Cecilia Anceschi
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Laura Naldi
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Alessandro Peri
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
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Sphingosine-1-Phosphate Induces ATP Release via Volume-Regulated Anion Channels in Breast Cell Lines. Life (Basel) 2021; 11:life11080851. [PMID: 34440595 PMCID: PMC8401269 DOI: 10.3390/life11080851] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 12/25/2022] Open
Abstract
High interstitial level of ATP and its lysate adenosine in the cancer microenvironment are considered a halo mark of cancer. Adenosine acts as a strong immune suppressor. However, the source of ATP release is unclear. We clarified the release of ATP via volume-regulated anion channels (VRACs) in breast cell lines using an ATP luminescence imaging system. We detected a slowly rising diffuse pattern of ATP release that was only observed in undifferentiated cells, not in differentiated primary cultured cells. This was confirmed by suppression with DCPIB, a blocker of VRACs, and shRNA for LRRC8A, an indispensable subunit of VRACs. We herein demonstrated that the inflammatory mediator sphingosine-1-phosphate (S1P), which exists abundantly in the cancer microenvironment, induced a diffuse pattern of ATP release isovolumetrically. The response was dose-dependent and suppressed by the knock-down of LRRC8A. It was also suppressed by blockers of S1P receptor 1 and 2 (W146 and JTE013, respectively). RTqPCR demonstrated the prominent presence of S1PR1 and S1PR2 mRNAs. We discussed the roles of S1P-induced ATP release in the cancer microenvironment.
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9
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Kuznetsov ML. Strength of the [Z-I···Hal] - and [Z-Hal···I] - Halogen Bonds: Electron Density Properties and Halogen Bond Length as Estimators of Interaction Energy. Molecules 2021; 26:2083. [PMID: 33916483 PMCID: PMC8038634 DOI: 10.3390/molecules26072083] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 11/29/2022] Open
Abstract
Bond energy is the main characteristic of chemical bonds in general and of non-covalent interactions in particular. Simple methods of express estimates of the interaction energy, Eint, using relationships between Eint and a property which is easily accessible from experiment is of great importance for the characterization of non-covalent interactions. In this work, practically important relationships between Eint and electron density, its Laplacian, curvature, potential, kinetic, and total energy densities at the bond critical point as well as bond length were derived for the structures of the [Z-I···Hal]- and [Z-Hal···I]- types bearing halogen bonds and involving iodine as interacting atom(s) (totally 412 structures). The mean absolute deviations for the correlations found were 2.06-4.76 kcal/mol.
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Affiliation(s)
- Maxim L. Kuznetsov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal; ; Tel.: +351-218-419-236
- Institute of Chemistry, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia
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10
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Boente-Juncal A, Raposo-García S, Louzao MC, Vale C, Botana LM. Targeting Chloride Ion Channels: New Insights into the Mechanism of Action of the Marine Toxin Azaspiracid. Chem Res Toxicol 2021; 34:865-879. [PMID: 33512997 DOI: 10.1021/acs.chemrestox.0c00494] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Azaspiracids (AZAs) are marine toxins produced by dinoflagellates belonging to the genera Azadinium and Amphidoma that caused human intoxications after consumption of contaminated fishery products, such as mussels. However, the exact mechanism for the AZA induced cytotoxic and neurotoxic effects is still unknown. In this study several pharmacological approaches were employed to evaluate the role of anion channels on the AZA effects that demonstrated that cellular anion dysregulation was involved in the toxic effects of these compounds. The results presented here demonstrated that volume regulated anion channels (VRACs) are affected by this group of toxins, and, because there is not any specific activator of VRACs besides the intracellular application of GTPγ-S molecule, this group of natural compounds could represent a powerful tool to analyze the role of these channels in cellular homeostasis. In addition to this, in this work, a detailed pharmacological approach was performed in order to elucidate the anion channels present in human HEK293 cells as well as their regulation by the marine toxins azaspiracids. Altogether, the data presented here demonstrated that the effect of azaspiracids in human cells was completely dependent on ATP-regulated anion channels, whose upregulation by these toxins could lead to regulatory volume decrease and underlie the reported toxicity of these compounds.
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Affiliation(s)
- Andrea Boente-Juncal
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - Sandra Raposo-García
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - M Carmen Louzao
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - Carmen Vale
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
| | - Luis M Botana
- Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus Universitario s/n, 27002 Lugo, España
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11
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Wang SC, Parpura V, Wang YF. Astroglial Regulation of Magnocellular Neuroendocrine Cell Activities in the Supraoptic Nucleus. Neurochem Res 2020; 46:2586-2600. [PMID: 33216313 DOI: 10.1007/s11064-020-03172-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 01/02/2023]
Abstract
Studies on the interactions between astrocytes and neurons in the hypothalamo-neurohypophysial system have significantly facilitated our understanding of the regulation of neural activities. This has been exemplified in the interactions between astrocytes and magnocellular neuroendocrine cells (MNCs) in the supraoptic nucleus (SON), specifically during osmotic stimulation and lactation. In response to changes in neurochemical environment in the SON, astrocytic morphology and functions change significantly, which further modulates MNC activity and the secretion of vasopressin and oxytocin. In osmotic regulation, short-term dehydration or water overload causes transient retraction or expansion of astrocytic processes, which increases or decreases the activity of SON neurons, respectively. Prolonged osmotic stimulation causes adaptive change in astrocytic plasticity in the SON, which allows osmosensory neurons to reserve osmosensitivity at new levels. During lactation, changes in neurochemical environment cause retraction of astrocytic processes around oxytocin neurons, which increases MNC's ability to secrete oxytocin. During suckling by a baby/pup, astrocytic processes in the mother/dams exhibit alternative retraction and expansion around oxytocin neurons, which mirrors intermittently synchronized activation of oxytocin neurons and the post-excitation inhibition, respectively. The morphological and functional plasticities of astrocytes depend on a series of cellular events involving glial fibrillary acidic protein, aquaporin 4, volume regulated anion channels, transporters and other astrocytic functional molecules. This review further explores mechanisms underlying astroglial regulation of the neuroendocrine neuronal activities in acute processes based on the knowledge from studies on the SON.
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Affiliation(s)
- Stephani C Wang
- Division of Cardiology, Department of Medicine, University of California-Irvine, Irvine, CA, USA
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, 35242, USA.
| | - Yu-Feng Wang
- Department of Physiology School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150086, China.
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12
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Woo J, Jang MW, Lee J, Koh W, Mikoshiba K, Lee CJ. The molecular mechanism of synaptic activity-induced astrocytic volume transient. J Physiol 2020; 598:4555-4572. [PMID: 32706443 DOI: 10.1113/jp279741] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/20/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Neuronal activity causes astrocytic volume change via K+ uptake through TREK-1 containing two-pore domain potassium channels. The volume transient is terminated by Cl- efflux through the Ca2+ -activated anion channel BEST1. The source of the Ca2+ required to open BEST1 appears to be the stretch-activated TRPA1 channel. Intense neuronal activity is synaptically coupled with a physical change in astrocytes via volume transients. ABSTRACT The brain volume changes dynamically and transiently upon intense neuronal activity through a tight regulation of ion concentrations and water movement across the plasma membrane of astrocytes. We have recently demonstrated that an intense neuronal activity and subsequent astrocytic AQP4-dependent volume transient are critical for synaptic plasticity and memory. We have also pharmacologically demonstrated a functional coupling between synaptic activity and the astrocytic volume transient. However, the precise molecular mechanisms of how intense neuronal activity and the astrocytic volume transient are coupled remain unclear. Here we utilized an intrinsic optical signal imaging technique combined with fluorescence imaging using ion sensitive dyes and molecular probes and electrophysiology to investigate the detailed molecular mechanisms in genetically modified mice. We report that a brief synaptic activity induced by a train stimulation (20 Hz, 1 s) causes a prolonged astrocytic volume transient (80 s) via K+ uptake through TREK-1 containing two-pore domain potassium (K2P) channels, but not Kir4.1 or NKCC1. This volume change is terminated by Cl- efflux through the Ca2+ -activated anion channel BEST1, but not the volume-regulated anion channel TTYH. The source of the Ca2+ required to open BEST1 appears to be the stretch-activated TRPA1 channel in astrocytes, but not IP3 R2. In summary, our study identifies several important astrocytic ion channels (AQP4, TREK-1, BEST1, TRPA1) as the key molecules leading to the neuronal activity-dependent volume transient in astrocytes. Our findings reveal new molecular and cellular mechanisms for the synaptic coupling of intense neuronal activity with a physical change in astrocytes via volume transients.
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Affiliation(s)
- Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Minwoo Wendy Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - Jaekwang Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Biology, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama, 351-0198, Japan
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, 02792, Republic of Korea
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13
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Measurement of Multi Ion Transport through Human Bronchial Epithelial Cell Line Provides an Insight into the Mechanism of Defective Water Transport in Cystic Fibrosis. MEMBRANES 2020; 10:membranes10030043. [PMID: 32178452 PMCID: PMC7142439 DOI: 10.3390/membranes10030043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/28/2022]
Abstract
We measured concentration changes of sodium, potassium, chloride ions, pH and the transepithelial potential difference by means of ion-selective electrodes, which were placed on both sides of a human bronchial epithelial 16HBE14σ cell line grown on a porous support in the presence of ion channel blockers. We found that, in the isosmotic transepithelial concentration gradient of either sodium or chloride ions, there is an electroneutral transport of the isosmotic solution of sodium chloride in both directions across the cell monolayer. The transepithelial potential difference is below 3 mV. Potassium and pH change plays a minor role in ion transport. Based on our measurements, we hypothesize that in a healthy bronchial epithelium, there is a dynamic balance between water absorption and secretion. Water absorption is caused by the action of two exchangers, Na/H and Cl/HCO3, secreting weakly dissociated carbonic acid in exchange for well dissociated NaCl and water. The water secretion phase is triggered by an apical low volume-dependent factor opening the Cystic Fibrosis Transmembrane Regulator CFTR channel and secreting anions that are accompanied by paracellular sodium and water transport.
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14
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Jia X, Liu Y, Li X, Huo C, Li D, Xu R, Hou L, Wang X. Norcepharadione B attenuates H 2O 2-induced neuronal injury by upregulating cellular antioxidants and inhibiting volume-sensitive Cl - channel. Exp Biol Med (Maywood) 2019; 244:1463-1474. [PMID: 31583895 DOI: 10.1177/1535370219881358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Oxidative stress acts as an essential culprit factor in the development of stroke and Alzheimer’s disease. Norcepharadione B possesses various pharmacologic features as an extract obtained from Houttuynia cordata. Nevertheless, the anti-apoptotic and neuroprotective characteristics of norcepharadione B remain unclear. In this study, the neuronal protection effect provided by norcepharadione B against injury caused by hydrogen peroxide (H2O2) in HT22 cell as well as the fundamental mechanism was systematically explored. The neurotoxicity assays of hippocampal cells, which were co-cultured with H2O2, showed that norcepharadione B had the ability to insulate the toxicity induced by H2O2 with significant reduced cell apoptosis. Besides, norcepharadione B potentiated the activity of superoxide dismutase (SOD), increased the level of glutathione (GSH), and decreased malondialdehyde content. The H2O2-induced apoptotic protein Bax was suppressed, and the anti-apoptotic protein Bcl-2 was boosted by norcepharadione B. Norcepharadione B promoted Akt phosphorylation and further upregulated heme oxygenase (HO-1) in cells exposed to oxidative stress. However, the inductive effect of HO-1 by norcepharadione B was shut off via the PI3K/Akt inhibitor LY294002. Furthermore, 2-h incubation with H2O2 substantially increased cell volume in HT22 cells, while norcepharadione B effectively alleviated such effect by interrupting the activation of VSOR Cl− channel. Collectively, our data revealed protective properties of norcepharadione B in resisting oxidative stress induced by H2O2 through elevation of HO-1 in the dependence of PI3K/Akt and in inhibiting H2O2-induced cell swelling by VSOR Cl− channel obstruction in HT22 cells. Impact statement Norcepharadione B is an aporphine alkaloid compound extracted from Chinese herb Houttuynia cordata. It was well known for its anti-inflammatory, anti-cancer, and anti-platelet aggregation outcomes. Our study demonstrated that Norcepharadione B protected hippocampal neurons against oxidative stress and the resultant cell apoptosis upon H2O2 exposure. Meanwhile, Norcepharadione B also substantially reduced cell swelling induced by H2O2 via inhibiting VSOR Cl− channel in neurons. These findings uncovered the potential mechanisms of Norcepharadione B in protecting neuron apoptosis under oxidative stress and propose that Norcepharadione B may serve as a favorable herb medicine for restoring neuronal injury in the pathogenesis of stroke together with other neurodegenerative diseases.
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Affiliation(s)
- Xin Jia
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Yan Liu
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Xing Li
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Cong Huo
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Dongtao Li
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Rong Xu
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Liming Hou
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
| | - Xiaoming Wang
- Department of Geriatrics, Xijing Hospital, Airforce Military Medical University, Xi'an, Shaanxi 710032, China
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15
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Han YE, Kwon J, Won J, An H, Jang MW, Woo J, Lee JS, Park MG, Yoon BE, Lee SE, Hwang EM, Jung JY, Park H, Oh SJ, Lee CJ. Tweety-homolog ( Ttyh) Family Encodes the Pore-forming Subunits of the Swelling-dependent Volume-regulated Anion Channel (VRAC swell) in the Brain. Exp Neurobiol 2019; 28:183-215. [PMID: 31138989 PMCID: PMC6526117 DOI: 10.5607/en.2019.28.2.183] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 11/19/2022] Open
Abstract
In the brain, a reduction in extracellular osmolality causes water-influx and swelling, which subsequently triggers Cl-- and osmolytes-efflux via volume-regulated anion channel (VRAC). Although LRRC8 family has been recently proposed as the pore-forming VRAC which is activated by low cytoplasmic ionic strength but not by swelling, the molecular identity of the pore-forming swelling-dependent VRAC (VRACswell) remains unclear. Here we identify and characterize Tweety-homologs (TTYH1, TTYH2, TTYH3) as the major VRACswell in astrocytes. Gene-silencing of all Ttyh1/2/3 eliminated hypo-osmotic-solution-induced Cl- conductance (ICl,swell) in cultured and hippocampal astrocytes. When heterologously expressed in HEK293T or CHO-K1 cells, each TTYH isoform showed a significant ICl,swell with similar aquaporin-4 dependency, pharmacological properties and glutamate permeability as ICl,swell observed in native astrocytes. Mutagenesis-based structure-activity analysis revealed that positively charged arginine residue at 165 in TTYH1 and 164 in TTYH2 is critical for the formation of the channel-pore. Our results demonstrate that TTYH family confers the bona fide VRACswell in the brain.
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Affiliation(s)
- Young-Eun Han
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jea Kwon
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Joungha Won
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Heeyoung An
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Minwoo Wendy Jang
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Je Sun Lee
- Molecular Neurobiology Laboratory, Dept. of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu 41068, Korea
| | - Min Gu Park
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul, 02841, Korea
| | - Bo-Eun Yoon
- Department of molecular biology, Dankook University, Cheonan 31116, Korea
| | - Seung Eun Lee
- Virus Facility, Research Animal Resource Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Eun Mi Hwang
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jae-Young Jung
- Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Hyungju Park
- Molecular Neurobiology Laboratory, Dept. of Structure and Function of Neural Network, Korea Brain Research Institute, Daegu 41068, Korea
| | - Soo-Jin Oh
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon 34126, Korea.,Department of Neuroscience, Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
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16
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Ion Channels: New Actors Playing in Chemotherapeutic Resistance. Cancers (Basel) 2019; 11:cancers11030376. [PMID: 30884858 PMCID: PMC6468599 DOI: 10.3390/cancers11030376] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/07/2019] [Accepted: 03/12/2019] [Indexed: 01/23/2023] Open
Abstract
In the battle against cancer cells, therapeutic modalities are drastically limited by intrinsic or acquired drug resistance. Resistance to therapy is not only common, but expected: if systemic agents used for cancer treatment are usually active at the beginning of therapy (i.e., 90% of primary breast cancers and 50% of metastases), about 30% of patients with early-stage breast cancer will have recurrent disease. Altered expression of ion channels is now considered as one of the hallmarks of cancer, and several ion channels have been linked to cancer cell resistance. While ion channels have been associated with cell death, apoptosis and even chemoresistance since the late 80s, the molecular mechanisms linking ion channel expression and/or function with chemotherapy have mostly emerged in the last ten years. In this review, we will highlight the relationships between ion channels and resistance to chemotherapy, with a special emphasis on the underlying molecular mechanisms.
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17
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Woo J, Han YE, Koh W, Won J, Park MG, An H, Lee CJ. Pharmacological Dissection of Intrinsic Optical Signal Reveals a Functional Coupling between Synaptic Activity and Astrocytic Volume Transient. Exp Neurobiol 2019; 28:30-42. [PMID: 30853822 PMCID: PMC6401548 DOI: 10.5607/en.2019.28.1.30] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 11/19/2022] Open
Abstract
The neuronal activity-dependent change in the manner in which light is absorbed or scattered in brain tissue is called the intrinsic optical signal (IOS), and provides label-free, minimally invasive, and high spatial (~100 µm) resolution imaging for visualizing neuronal activity patterns. IOS imaging in isolated brain slices measured at an infrared wavelength (>700 nm) has recently been attributed to the changes in light scattering and transmittance due to aquaporin-4 (AQP4)-dependent astrocytic swelling. The complexity of functional interactions between neurons and astrocytes, however, has prevented the elucidation of the series of molecular mechanisms leading to the generation of IOS. Here, we pharmacologically dissected the IOS in the acutely prepared brain slices of the stratum radiatum of the hippocampus, induced by 1 s/20 Hz electrical stimulation of Schaffer-collateral pathway with simultaneous measurement of the activity of the neuronal population by field potential recordings. We found that 55% of IOSs peak upon stimulation and originate from postsynaptic AMPA and NMDA receptors. The remaining originated from presynaptic action potentials and vesicle fusion. Mechanistically, the elevated extracellular glutamate and K+ during synaptic transmission were taken up by astrocytes via a glutamate transporter and quinine-sensitive K2P channel, followed by an influx of water via AQP-4. We also found that the decay of IOS is mediated by the DCPIB- and NPPB-sensitive anion channels in astrocytes. Altogether, our results demonstrate that the functional coupling between synaptic activity and astrocytic transient volume change during excitatory synaptic transmission is the major source of IOS.
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Affiliation(s)
- Junsung Woo
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Young-Eun Han
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Wuhyun Koh
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
| | - Joungha Won
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,Department of Biological Sciences, Korea Advanced Institutes of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Min Gu Park
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - Heeyoung An
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea.,KU-KIST, Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea
| | - C Justin Lee
- Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.,Department of Neuroscience, Division of Bio-medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34126, Korea
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18
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König B, Stauber T. Biophysics and Structure-Function Relationships of LRRC8-Formed Volume-Regulated Anion Channels. Biophys J 2019; 116:1185-1193. [PMID: 30871717 PMCID: PMC6451053 DOI: 10.1016/j.bpj.2019.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 01/31/2019] [Accepted: 02/19/2019] [Indexed: 01/25/2023] Open
Abstract
Volume-regulated anion channels (VRACs) are key players in regulatory volume decrease of vertebrate cells by mediating the extrusion of chloride and organic osmolytes. They play additional roles in various physiological processes beyond their role in osmotic volume regulation. VRACs are formed by heteromers of LRRC8 proteins; LRRC8A (also called SWELL1) is an essential subunit that combines with any of its paralogs, LRRC8B–E, to form hexameric VRAC complexes. The subunit composition of VRACs determines electrophysiological characteristics of their anion transport such as single-channel conductance, outward rectification, and depolarization-dependent inactivation kinetics. In addition, differently composed VRACs conduct diverse substrates, such as LRRC8D enhancing VRAC permeability to organic substances like taurine or cisplatin. Here, after a recapitulation of the biophysical properties of VRAC-mediated ion and osmolyte transport, we summarize the insights gathered since the molecular identification of VRACs. We describe the recently solved structures of LRRC8 complexes and discuss them in terms of their structure-function relationships. These studies open up many potential avenues for future research.
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Affiliation(s)
- Benjamin König
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany
| | - Tobias Stauber
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany.
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19
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Okada Y, Okada T, Sato-Numata K, Islam MR, Ando-Akatsuka Y, Numata T, Kubo M, Shimizu T, Kurbannazarova RS, Marunaka Y, Sabirov RZ. Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties. Pharmacol Rev 2019; 71:49-88. [PMID: 30573636 DOI: 10.1124/pr.118.015917] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
There are a number of mammalian anion channel types associated with cell volume changes. These channel types are classified into two groups: volume-activated anion channels (VAACs) and volume-correlated anion channels (VCACs). VAACs can be directly activated by cell swelling and include the volume-sensitive outwardly rectifying anion channel (VSOR), which is also called the volume-regulated anion channel; the maxi-anion channel (MAC or Maxi-Cl); and the voltage-gated anion channel, chloride channel (ClC)-2. VCACs can be facultatively implicated in, although not directly activated by, cell volume changes and include the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, the Ca2+-activated Cl- channel (CaCC), and the acid-sensitive (or acid-stimulated) outwardly rectifying anion channel. This article describes the phenotypical properties and activation mechanisms of both groups of anion channels, including accumulating pieces of information on the basis of recent molecular understanding. To that end, this review also highlights the molecular identities of both anion channel groups; in addition to the molecular identities of ClC-2 and CFTR, those of CaCC, VSOR, and Maxi-Cl were recently identified by applying genome-wide approaches. In the last section of this review, the most up-to-date information on the pharmacological properties of both anion channel groups, especially their half-maximal inhibitory concentrations (IC50 values) and voltage-dependent blocking, is summarized particularly from the standpoint of pharmacological distinctions among them. Future physiologic and pharmacological studies are definitely warranted for therapeutic targeting of dysfunction of VAACs and VCACs.
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Affiliation(s)
- Yasunobu Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Toshiaki Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Kaori Sato-Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Md Rafiqul Islam
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yuhko Ando-Akatsuka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Tomohiro Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Machiko Kubo
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Takahiro Shimizu
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ranohon S Kurbannazarova
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yoshinori Marunaka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ravshan Z Sabirov
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
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20
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Wilson CS, Mongin AA. Cell Volume Control in Healthy Brain and Neuropathologies. CURRENT TOPICS IN MEMBRANES 2018; 81:385-455. [PMID: 30243438 DOI: 10.1016/bs.ctm.2018.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Regulation of cellular volume is a critical homeostatic process that is intimately linked to ionic and osmotic balance in the brain tissue. Because the brain is encased in the rigid skull and has a very complex cellular architecture, even minute changes in the volume of extracellular and intracellular compartments have a very strong impact on tissue excitability and function. The failure of cell volume control is a major feature of several neuropathologies, such as hyponatremia, stroke, epilepsy, hyperammonemia, and others. There is strong evidence that such dysregulation, especially uncontrolled cell swelling, plays a major role in adverse pathological outcomes. To protect themselves, brain cells utilize a variety of mechanisms to maintain their optimal volume, primarily by releasing or taking in ions and small organic molecules through diverse volume-sensitive ion channels and transporters. In principle, the mechanisms of cell volume regulation are not unique to the brain and share many commonalities with other tissues. However, because ions and some organic osmolytes (e.g., major amino acid neurotransmitters) have a strong impact on neuronal excitability, cell volume regulation in the brain is a surprisingly treacherous process, which may cause more harm than good. This topical review covers the established and emerging information in this rapidly developing area of physiology.
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Affiliation(s)
- Corinne S Wilson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Alexander A Mongin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Biophysics and Functional Diagnostics, Siberian State Medical University, Tomsk, Russian Federation
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21
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Nakajima K, Takakura H, Shimizu Y, Ogawa M. Changes in plasma membrane damage inducing cell death after treatment with near-infrared photoimmunotherapy. Cancer Sci 2018; 109:2889-2896. [PMID: 29949672 PMCID: PMC6125438 DOI: 10.1111/cas.13713] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 06/25/2018] [Indexed: 12/12/2022] Open
Abstract
Near‐infrared photoimmunotherapy (NIR‐PIT) is a new cancer phototherapy modality using an antibody conjugated to a photosensitizer, IRDye700DX. When the conjugate binds to the plasma membrane and is exposed to NIR light, NIR‐PIT‐treated cells undergo swelling, and target‐selective necrotic/immunogenic cell death is induced. However, the cytotoxic mechanism of NIR‐PIT has not been elucidated. In order to understand the mechanism, it is important to elucidate how the damage to the plasma membrane induced by NIR light irradiation changes over time. Thus, in the present study, we investigated the changes in plasma membrane permeability using ions and molecules of various sizes. Na+ flowed into cells immediately after NIR light irradiation, even when the function of transporters or channels was blocked. Subsequently, fluorescent molecules larger than Na+ entered the cells, but the damage was not large enough for dextran to pass through at early time points. To assess these phenomena quantitatively, membrane permeability was estimated using radiolabeled ions and molecules: 111InCl3, 111In‐DTPA, and 3H‐H2O, and comparable results were obtained. Although minute plasma membrane perforations usually do not induce cell death, our results suggest that the minute damage induced by NIR‐PIT was irreversibly extended with time. In conclusion, minute plasma membrane damage is a trigger for the increase in plasma membrane permeability, cell swelling, and necrotic/immunogenic cell death in NIR‐PIT. Our findings provide new insight into the cytotoxic mechanism of NIR‐PIT.
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Affiliation(s)
- Kohei Nakajima
- Laboratory of Bioanalysis and Molecular Imaging, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Hideo Takakura
- Laboratory of Bioanalysis and Molecular Imaging, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Yoichi Shimizu
- Laboratory of Bioanalysis and Molecular Imaging, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Mikako Ogawa
- Laboratory of Bioanalysis and Molecular Imaging, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Japan
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22
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Abstract
Insulin secretion is initiated by activation of voltage-gated Ca2+ channels (VGCC) to trigger Ca2+-mediated insulin vesicle fusion with the β-cell plasma membrane. The firing of VGCC requires β-cell membrane depolarization, which is regulated by a balance of depolarizing and hyperpolarizing ionic currents. Here, we show that SWELL1 mediates a swell-activated, depolarizing chloride current (ICl,SWELL) in both murine and human β-cells. Hypotonic and glucose-stimulated β-cell swelling activates SWELL1-mediated ICl,SWELL and this contributes to membrane depolarization and activation of VGCC-dependent intracellular calcium signaling. SWELL1 depletion in MIN6 cells and islets significantly impairs glucose-stimulated insulin secretion. Tamoxifen-inducible β-cell-targeted Swell1 KO mice have normal fasting serum glucose and insulin levels but impaired glucose-stimulated insulin secretion and glucose tolerance; and this is further exacerbated in mild obesity. Our results reveal that β-cell SWELL1 modulates insulin secretion and systemic glycaemia by linking glucose-mediated β-cell swelling to membrane depolarization and activation of VGCC-triggered calcium signaling.
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23
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Kang C, Xie L, Gunasekar SK, Mishra A, Zhang Y, Pai S, Gao Y, Kumar A, Norris AW, Stephens SB, Sah R. SWELL1 is a glucose sensor regulating β-cell excitability and systemic glycaemia. Nat Commun 2018; 9:367. [PMID: 29371604 PMCID: PMC5785485 DOI: 10.1038/s41467-017-02664-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 12/15/2017] [Indexed: 12/11/2022] Open
Abstract
Insulin secretion is initiated by activation of voltage-gated Ca2+ channels (VGCC) to trigger Ca2+-mediated insulin vesicle fusion with the β-cell plasma membrane. The firing of VGCC requires β-cell membrane depolarization, which is regulated by a balance of depolarizing and hyperpolarizing ionic currents. Here, we show that SWELL1 mediates a swell-activated, depolarizing chloride current (ICl,SWELL) in both murine and human β-cells. Hypotonic and glucose-stimulated β-cell swelling activates SWELL1-mediated ICl,SWELL and this contributes to membrane depolarization and activation of VGCC-dependent intracellular calcium signaling. SWELL1 depletion in MIN6 cells and islets significantly impairs glucose-stimulated insulin secretion. Tamoxifen-inducible β-cell-targeted Swell1 KO mice have normal fasting serum glucose and insulin levels but impaired glucose-stimulated insulin secretion and glucose tolerance; and this is further exacerbated in mild obesity. Our results reveal that β-cell SWELL1 modulates insulin secretion and systemic glycaemia by linking glucose-mediated β-cell swelling to membrane depolarization and activation of VGCC-triggered calcium signaling.
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Affiliation(s)
- Chen Kang
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Litao Xie
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Susheel K Gunasekar
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Anil Mishra
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Yanhui Zhang
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Saachi Pai
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Yiwen Gao
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Ashutosh Kumar
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
| | - Andrew W Norris
- Department of Pediatrics, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
- Fraternal Order of the Eagles Diabetes Research Center, Iowa City, IA, 52242, USA
| | - Samuel B Stephens
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA
- Fraternal Order of the Eagles Diabetes Research Center, Iowa City, IA, 52242, USA
| | - Rajan Sah
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242, USA.
- Fraternal Order of the Eagles Diabetes Research Center, Iowa City, IA, 52242, USA.
- Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, USA.
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24
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Gradogna A, Gavazzo P, Boccaccio A, Pusch M. Subunit-dependent oxidative stress sensitivity of LRRC8 volume-regulated anion channels. J Physiol 2017; 595:6719-6733. [PMID: 28841766 DOI: 10.1113/jp274795] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 08/16/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Swelling-activated anion currents are modulated by oxidative conditions, but it is unknown if oxidation acts directly on the LRRC8 channel-forming proteins or on regulatory factors. We found that LRRC8A-LRRC8E heteromeric channels are dramatically activated by oxidation of intracellular cysteines, whereas LRRC8A-LRRC8C and LRRC8A-LRRC8D heteromers are inhibited by oxidation. Volume-regulated anion currents in Jurkat T lymphocytes were inhibited by oxidation, in agreement with a low expression of the LRRC8E subunit in these cells. Our results show that LRRC8 channel proteins are directly modulated by oxidation in a subunit-specific manner. ABSTRACT The volume-regulated anion channel (VRAC) is formed by heteromers of LRRC8 proteins containing the essential LRRC8A subunit and at least one among the LRRC8B-E subunits. Reactive oxygen species (ROS) play physiological and pathophysiological roles and VRAC channels are highly ROS sensitive. However, it is unclear if ROS act directly on the channels or on molecules involved in the activation pathway. We used fluorescently tagged LRRC8 proteins that yield large constitutive currents to test direct effects of oxidation. We found that 8A/8E heteromers are dramatically potentiated (more than 10-fold) by oxidation of intracellular cysteine residues by chloramine-T or tert-butyl hydroperoxide. Oxidation was, however, not necessary for hypotonicity-induced activation. In contrast, 8A/8C and 8A/8D heteromers were strongly inhibited by oxidation. Endogenous VRAC currents in Jurkat T lymphocytes were similarly inhibited by oxidation, in agreement with the finding that LRRC8C and LRRC8D subunits were more abundantly expressed than LRRC8E in Jurkat cells. Our results show that LRRC8 channels are directly modulated by oxidation in a subunit-dependent manner.
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Affiliation(s)
- Antonella Gradogna
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini 6, I-16149, Genova, Italy
| | - Paola Gavazzo
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini 6, I-16149, Genova, Italy
| | - Anna Boccaccio
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini 6, I-16149, Genova, Italy
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Via De Marini 6, I-16149, Genova, Italy
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25
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Marunaka Y. The Mechanistic Links between Insulin and Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Cl - Channel. Int J Mol Sci 2017; 18:ijms18081767. [PMID: 28805732 PMCID: PMC5578156 DOI: 10.3390/ijms18081767] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 07/31/2017] [Accepted: 08/10/2017] [Indexed: 12/30/2022] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel belongs to the ATP-binding cassette (ABC) transporter superfamily and regulates Cl− secretion in epithelial cells for water secretion. Loss-of-function mutations to the CFTR gene cause dehydrated mucus on the apical side of epithelial cells and increase the susceptibility of bacterial infection, especially in the airway and pulmonary tissues. Therefore, research on the molecular properties of CFTR, such as its gating mechanism and subcellular trafficking, have been intensively pursued. Dysregulated CFTR trafficking is one of the major pathological hallmarks in cystic fibrosis (CF) patients bearing missense mutations in the CFTR gene. Hormones that activate cAMP signaling, such as catecholamine, have been found to regulate the intracellular trafficking of CFTR. Insulin is one of the hormones that regulate cAMP production and promote trafficking of transmembrane proteins to the plasma membrane. The functional interactions between insulin and CFTR have not yet been clearly defined. In this review article, I review the roles of CFTR in epithelial cells, its regulatory role in insulin secretion, and a mechanism of CFTR regulation by insulin.
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Affiliation(s)
- Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan.
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26
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Zhang Y, Xie L, Gunasekar SK, Tong D, Mishra A, Gibson WJ, Wang C, Fidler T, Marthaler B, Klingelhutz A, Abel ED, Samuel I, Smith JK, Cao L, Sah R. SWELL1 is a regulator of adipocyte size, insulin signalling and glucose homeostasis. Nat Cell Biol 2017; 19:504-517. [PMID: 28436964 PMCID: PMC5415409 DOI: 10.1038/ncb3514] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 03/16/2017] [Indexed: 12/15/2022]
Abstract
Adipocytes undergo considerable volumetric expansion in the setting of obesity. It has been proposed that such marked increases in adipocyte size may be sensed via adipocyte-autonomous mechanisms to mediate size-dependent intracellular signalling. Here, we show that SWELL1 (LRRC8a), a member of the Leucine-Rich Repeat Containing protein family, is an essential component of a volume-sensitive ion channel (VRAC) in adipocytes. We find that SWELL1-mediated VRAC is augmented in hypertrophic murine and human adipocytes in the setting of obesity. SWELL1 regulates adipocyte insulin-PI3K-AKT2-GLUT4 signalling, glucose uptake and lipid content via SWELL1 C-terminal leucine-rich repeat domain interactions with GRB2/Cav1. Silencing GRB2 in SWELL1 KO adipocytes rescues insulin-pAKT2 signalling. In vivo, shRNA-mediated SWELL1 knockdown and adipose-targeted SWELL1 knockout reduce adiposity and adipocyte size in obese mice while impairing systemic glycaemia and insulin sensitivity. These studies identify SWELL1 as a cell-autonomous sensor of adipocyte size that regulates adipocyte growth, insulin sensitivity and glucose tolerance.
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Affiliation(s)
- Yanhui Zhang
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Litao Xie
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Susheel K. Gunasekar
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Dan Tong
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Anil Mishra
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | | | - Chuansong Wang
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, Ohio
| | - Trevor Fidler
- Fraternal Order of the Eagles Diabetes Research Center, Iowa City, IA, 52242
| | - Brodie Marthaler
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Aloysius Klingelhutz
- Department of Microbiology, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - E. Dale Abel
- Fraternal Order of the Eagles Diabetes Research Center, Iowa City, IA, 52242
| | - Isaac Samuel
- Department of Surgery, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Jessica K. Smith
- Department of Surgery, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
| | - Lei Cao
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, Ohio
| | - Rajan Sah
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA, 52242
- Fraternal Order of the Eagles Diabetes Research Center, Iowa City, IA, 52242
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27
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Wang L, Shen M, Guo X, Wang B, Xia Y, Wang N, Zhang Q, Jia L, Wang X. Volume-sensitive outwardly rectifying chloride channel blockers protect against high glucose-induced apoptosis of cardiomyocytes via autophagy activation. Sci Rep 2017; 7:44265. [PMID: 28300155 PMCID: PMC5353972 DOI: 10.1038/srep44265] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 02/07/2017] [Indexed: 12/14/2022] Open
Abstract
Hyperglycemia is a well-characterized contributing factor for cardiac dysfunction and heart failure among diabetic patients. Apoptosis of cardiomyocytes plays a major role during the onset and pathogenesis of diabetic cardiomyopathy (DCM). Nonetheless, the molecular machinery underlying hyperglycemia-induced cardiac damage and cell death remains elusive. In the present study, we found that chloride channel blockers, 4,4'-diisothiocya-natostilbene-2,2'- disulfonic acid (DIDS) and 4-(2-butyl-6,7-dichlor-2-cyclopentyl-indan-1-on-5-yl) oxybutyric acid (DCPIB), inhibited high glucose-activated volume-sensitive outwardly rectifying (VSOR) Cl- channel and improved the viability of cardiomyocytes. High glucose induced cardiomyocyte apoptosis by suppressing the autophagic stress, which can be reversed via blockade of VSOR Cl- channel. VSOR activation in high glucose-treated cardiomyocytes was attributed to increased intracellular levels of reactive oxygen species (ROS). Taken together, our study unraveled a role of VSOR chloride currents in impaired autophagy and increased apoptosis of high glucose-exposed cardiomyocyte, and has implications for a therapeutic potential of VSOR chloride channel blockers in DCM.
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Affiliation(s)
- Lin Wang
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Mingzhi Shen
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.,Department of Cardiology, Hainan Branch of PLA General Hospital, Sanya 572031, China
| | - Xiaowang Guo
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Bo Wang
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Yuesheng Xia
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Ning Wang
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Qian Zhang
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Lintao Jia
- Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi'an 710032, China
| | - Xiaoming Wang
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
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28
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Gradogna A, Gaitán-Peñas H, Boccaccio A, Estévez R, Pusch M. Cisplatin activates volume sensitive LRRC8 channel mediated currents in Xenopus oocytes. Channels (Austin) 2017; 11:254-260. [PMID: 28121479 DOI: 10.1080/19336950.2017.1284717] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
LRRC8 proteins have been shown to underlie the ubiquitous volume regulated anion channel (VRAC). VRAC channels are composed of the LRRC8A subunit and at least one among the LRRC8B-E subunits. In addition to their role in volume regulation, LRRC8 proteins have been implicated in the uptake of chemotherapeutic agents. We had found that LRRC8 channels can be conveniently expressed in Xenopus oocytes, a system without endogenous VRAC activity. The fusion with fluorescent proteins yielded constitutive activity for A/C, A/D and A/E heteromers. Here we tested the effect of the anticancer drug cisplatin on LRRC8A-VFP/8E-mCherry and LRRC8A-VFP/8D-mCherry co-expressing oocytes. Incubation with cisplatin dramatically activated currents for both subunit combinations, confirming that VRAC channels provide an uptake pathway for cisplatin and that intracellular cisplatin accumulation strongly activates the channels. Thus, specific activators of LRRC8 proteins might be useful tools to counteract chemotherapeutic drug resistance.
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Affiliation(s)
| | - Héctor Gaitán-Peñas
- b Departament de Ciències Fisiològiques II , Unitat de Fisiologia, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat , Barcelona , Spain.,c Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII , Barcelona , Spain
| | - Anna Boccaccio
- a Institute of Biophysics, National Research Council , Genova , Italy
| | - Raúl Estévez
- b Departament de Ciències Fisiològiques II , Unitat de Fisiologia, IDIBELL-Universitat de Barcelona, L'Hospitalet de Llobregat , Barcelona , Spain.,c Centro de Investigación en red de enfermedades raras (CIBERER), ISCIII , Barcelona , Spain
| | - Michael Pusch
- a Institute of Biophysics, National Research Council , Genova , Italy
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29
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Choi H, Ettinger N, Rohrbough J, Dikalova A, Nguyen HN, Lamb FS. LRRC8A channels support TNFα-induced superoxide production by Nox1 which is required for receptor endocytosis. Free Radic Biol Med 2016; 101:413-423. [PMID: 27838438 PMCID: PMC5206799 DOI: 10.1016/j.freeradbiomed.2016.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 11/23/2022]
Abstract
Leucine Rich Repeat Containing 8A (LRRC8A) is a required component of volume-regulated anion channels (VRACs). In vascular smooth muscle cells, tumor necrosis factor-α (TNFα) activates VRAC via type 1 TNFα receptors (TNFR1), and this requires superoxide (O2•-) production by NADPH oxidase 1 (Nox1). VRAC inhibitors suppress the inflammatory response to TNFα by an unknown mechanism. We hypothesized that LRRC8A directly supports Nox1 activity, providing a link between VRAC current and inflammatory signaling. VRAC inhibition by 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) impaired NF-κB activation by TNFα. LRRC8A siRNA reduced the magnitude of VRAC and inhibited TNFα-induced NF-κB activation, iNOS and VCAM expression, and proliferation of VSMCs. Signaling steps disrupted by both siLRRC8A and DCPIB included; extracellular O2•- production by Nox1, c-Jun N-terminal kinase (JNK) phosphorylation and endocytosis of TNFR1. Extracellular superoxide dismutase, but not catalase, selectively inhibited TNFR1 endocytosis and JNK phosphorylation. Thus, O2•- is the critical extracellular oxidant for TNFR signal transduction. Reducing JNK expression (siJNK) increased extracellular O2•- suggesting that JNK provides important negative feedback regulation to Nox1 at the plasma membrane. LRRC8A co-localized by immunostaining, and co-immunoprecipitated with, both Nox1 and its p22phox subunit. LRRC8A is a component of the Nox1 signaling complex. It is required for extracellular O2•- production, which is in turn essential for TNFR1 endocytosis. These data are the first to provide a molecular mechanism for the potent anti-proliferative and anti-inflammatory effects of VRAC inhibition.
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Affiliation(s)
- Hyehun Choi
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Nicholas Ettinger
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, United States
| | - Jeffrey Rohrbough
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Anna Dikalova
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Hong N Nguyen
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, United States
| | - Fred S Lamb
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, United States.
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ClC-3 Chloride Channel Proteins Regulate the Cell Cycle by Up-regulating cyclin D1-CDK4/6 through Suppressing p21/p27 Expression in Nasopharyngeal Carcinoma Cells. Sci Rep 2016; 6:30276. [PMID: 27451945 PMCID: PMC4959003 DOI: 10.1038/srep30276] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/03/2016] [Indexed: 12/24/2022] Open
Abstract
It was shown in this study that knockdown of ClC-3 expression by ClC-3 siRNA prevented the activation of hypotonicity-induced chloride currents, and arrested cells at the G0/G1 phase in nasopharyngeal carcinoma CNE-2Z cells. Reconstitution of ClC-3 expression with ClC-3 expression plasmids could rescue the cells from the cell cycle arrest caused by ClC-3 siRNA treatments. Transfection of cells with ClC-3 siRNA decreased the expression of cyclin D1, cyclin dependent kinase 4 and 6, and increased the expression of cyclin dependent kinase inhibitors (CDKIs), p21 and p27. Pretreatments of cells with p21 and p27 siRNAs depleted the inhibitory effects of ClC-3 siRNA on the expression of CDK4 and CDK6, but not on that of cyclin D1, indicating the requirement of p21 and p27 for the inhibitory effects of ClC-3 siRNA on CDK4 and CDK6 expression. ClC-3 siRNA inhibited cells to progress from the G1 phase to the S phase, but pretreatments of cells with p21 and p27 siRNAs abolished the inhibitory effects of ClC-3 siRNA on the cell cycle progress. Our data suggest that ClC-3 may regulate cell cycle transition between G0/G1 and S phases by up-regulation of the expression of CDK4 and CDK6 through suppression of p21 and p27 expression.
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Kudou M, Shiozaki A, Kosuga T, Ichikawa D, Konishi H, Morimura R, Komatsu S, Ikoma H, Fujiwara H, Okamoto K, Hosogi S, Nakahari T, Marunaka Y, Otsuji E. Inhibition of Regulatory Volume Decrease Enhances the Cytocidal Effect of Hypotonic Shock in Hepatocellular Carcinoma. J Cancer 2016; 7:1524-33. [PMID: 27471568 PMCID: PMC4964136 DOI: 10.7150/jca.15181] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/04/2016] [Indexed: 12/16/2022] Open
Abstract
Background: Hypotonic shock induces cytocidal effects through cell rupture, and cancer therapy based on this mechanism has been clinically administered to hepatocellular carcinoma patients. We herein investigated the effectiveness of hypotonic shock combined with the inhibition of regulatory volume decrease as cancer therapy for hepatocellular carcinoma. Methods: Morphological changes in human hepatocellular carcinoma cell lines were observed under a differential interference contrast microscope connected to a high-speed digital video camera. Cell volume changes under hypotonic shock with or without chloride, potassium, or water channel blockers were observed using a high-resolution flow cytometer. In order to investigate cytocidal effects, the number of surviving cells was compared after exposure to hypotonic solution with and without each channel blocker (re-incubation experiment). Results: Video recordings showed that cells exposed to distilled water rapidly swelled and then ruptured. Cell volume measurements revealed regulatory volume decrease under mild hypotonic shock, whereas severe hypotonic shock increased the number of broken fragments as a result of cell rupture. Moreover, regulatory volume decrease was inhibited in cells treated with each channel blocker. Re-incubation experiments showed the cytocidal effects of hypotonic shock in cells exposed to hypotonic solution, and additional treatments with each channel blocker enhanced these effects. Conclusion: The inhibition of regulatory volume decrease with chloride, potassium, or water channel blockers may enhance the cytocidal effects of hypotonic shock in hepatocellular carcinoma. Hypotonic shock combined with the inhibition of regulatory volume decrease was a more effective therapy than hypotonic shock alone.
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Affiliation(s)
- Michihiro Kudou
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Atsushi Shiozaki
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Toshiyuki Kosuga
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Daisuke Ichikawa
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hirotaka Konishi
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Ryo Morimura
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shuhei Komatsu
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hisashi Ikoma
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hitoshi Fujiwara
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Kazuma Okamoto
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shigekuni Hosogi
- 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Takashi Nakahari
- 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Yoshinori Marunaka
- 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;; 3. Japan Institute for Food Education and Health, Heian Jogakuin (St. Agnes') University, Kyoto, 602-8013, Japan
| | - Eigo Otsuji
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
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Microglial Contact Prevents Excess Depolarization and Rescues Neurons from Excitotoxicity. eNeuro 2016; 3:eN-NWR-0004-16. [PMID: 27390772 PMCID: PMC4916329 DOI: 10.1523/eneuro.0004-16.2016] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 04/29/2016] [Accepted: 05/18/2016] [Indexed: 12/20/2022] Open
Abstract
Microglia survey and directly contact neurons in both healthy and damaged brain, but the mechanisms and functional consequences of these contacts are not yet fully elucidated. Combining two-photon imaging and patch clamping, we have developed an acute experimental model for studying the role of microglia in CNS excitotoxicity induced by neuronal hyperactivity. Our model allows us to simultaneously examine the effects of repetitive supramaximal stimulation on axonal morphology, neuronal membrane potential, and microglial migration, using cortical brain slices from Iba-1 eGFP mice. We demonstrate that microglia exert an acute and highly localized neuroprotective action under conditions of neuronal hyperactivity. Evoking repetitive action potentials in individual layer 2/3 pyramidal neurons elicited swelling of axons, but not dendrites, which was accompanied by a large, sustained depolarization of soma membrane potential. Microglial processes migrated to these swollen axons in a mechanism involving both ATP and glutamate release via volume-activated anion channels. This migration was followed by intensive microglial wrapping of affected axons and, in some cases, the removal of axonal debris that induced a rapid soma membrane repolarization back to resting potentials. When the microglial migration was pharmacologically blocked, the activity-induced depolarization continued until cell death ensued, demonstrating that the microglia–axon contact served to prevent pathological depolarization of the soma and maintain neuronal viability. This is a novel aspect of microglia surveillance: detecting, wrapping, and rescuing neuronal soma from damage due to excessive activity.
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Ullrich F, Reincke SM, Voss FK, Stauber T, Jentsch TJ. Inactivation and Anion Selectivity of Volume-regulated Anion Channels (VRACs) Depend on C-terminal Residues of the First Extracellular Loop. J Biol Chem 2016; 291:17040-8. [PMID: 27325695 DOI: 10.1074/jbc.m116.739342] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Indexed: 11/06/2022] Open
Abstract
Canonical volume-regulated anion channels (VRACs) are crucial for cell volume regulation and have many other important roles, including tumor drug resistance and release of neurotransmitters. Although VRAC-mediated swelling-activated chloride currents (ICl,vol) have been studied for decades, exploration of the structure-function relationship of VRAC has become possible only after the recent discovery that VRACs are formed by differently composed heteromers of LRRC8 proteins. Inactivation of ICl,vol at positive potentials, a typical hallmark of VRACs, strongly varies between native cell types. Exploiting the large differences in inactivation between different LRRC8 heteromers, we now used chimeras assembled from isoforms LRRC8C and LRRC8E to uncover a highly conserved extracellular region preceding the second LRRC8 transmembrane domain as a major determinant of ICl,vol inactivation. Point mutations identified two amino acids (Lys-98 and Asp-100 in LRRC8A and equivalent residues in LRRC8C and -E), which upon charge reversal strongly altered the kinetics and voltage dependence of inactivation. Importantly, charge reversal at the first position also reduced the iodide > chloride permeability of ICl,vol This change in selectivity was stronger when both the obligatory LRRC8A subunit and the other co-expressed isoform (LRR8C or -E) carried such mutations. Hence, the C-terminal part of the first extracellular loop not only determines VRAC inactivation but might also participate in forming its outer pore. Inactivation of VRACs may involve a closure of the extracellular mouth of the permeation pathway.
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Affiliation(s)
- Florian Ullrich
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, the Graduate Program, Freie Universität Berlin, D-14195 Berlin, and
| | - S Momsen Reincke
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin
| | - Felizia K Voss
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin
| | - Tobias Stauber
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin
| | - Thomas J Jentsch
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, Neurocure, Charité Universitätsmedizin, D-10117 Berlin, Germany
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34
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Xie C, Cao X, Chen X, Wang D, Zhang WK, Sun Y, Hu W, Zhou Z, Wang Y, Huang P. Mechanosensitivity of wild-type and G551D cystic fibrosis transmembrane conductance regulator (CFTR) controls regulatory volume decrease in simple epithelia. FASEB J 2016; 30:1579-89. [PMID: 26683699 PMCID: PMC6137689 DOI: 10.1096/fj.15-283002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/08/2015] [Indexed: 12/22/2022]
Abstract
Mutations of cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial ligand-gated anion channel, are associated with the lethal genetic disease cystic fibrosis. The CFTR G551D mutation impairs ATP hydrolysis and thereby makes CFTR refractory to cAMP stimulation. Both wild-type (WT) and G551D CFTR have been implicated in regulatory volume decrease (RVD), but the underlying mechanism remains incompletely understood. Here, we show that the channel activity of both WT and G551D CFTR is directly stimulated by mechanical perturbation induced by cell swelling at the single-channel, cellular, and tissue levels. Hypotonicity activated CFTR single channels in cell-attached membrane patches and WT-CFTR-mediated short-circuit current (Isc) in Calu-3 cells, and this was independent of Ca(2+)and cAMP/PKA signaling. Genetic suppression and ablation but not G551D mutation of CFTR suppressed the hypotonicity- and stretch-inducedIscin Calu-3 cells and mouse duodena. Moreover, ablation but not G551D mutation of the CFTR gene inhibited the RVD of crypts isolated from mouse intestine; more importantly, CFTR-specific blockers markedly suppressed RVD in both WT- and G551D CFTR mice, demonstrating for the first time that the channel activity of both WT and G551D CFTR is required for epithelial RVD. Our findings uncover a previously unrecognized mechanism underlying CFTR involvement in epithelial RVD and suggest that the mechanosensitivity of G551D CFTR might underlie the mild phenotypes resulting from this mutation.-Xie, C., Cao, X., Chen, X, Wang, D., Zhang, W. K., Sun, Y., Hu, W., Zhou, Z., Wang, Y., Huang, P. Mechanosensitivity of wild-type and G551D cystic fibrosis transmembrane conductance regulator (CFTR) controls regulatory volume decrease in simple epithelia.
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Affiliation(s)
- Changyan Xie
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xu Cao
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xibing Chen
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Dong Wang
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wei Kevin Zhang
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ying Sun
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wenbao Hu
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zijing Zhou
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yan Wang
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Pingbo Huang
- *Division of Life Science, Division of Biomedical Engineering, and State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
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35
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Jentsch TJ. VRACs and other ion channels and transporters in the regulation of cell volume and beyond. Nat Rev Mol Cell Biol 2016; 17:293-307. [PMID: 27033257 DOI: 10.1038/nrm.2016.29] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cells need to regulate their volume to counteract osmotic swelling or shrinkage, as well as during cell division, growth, migration and cell death. Mammalian cells adjust their volume by transporting potassium, sodium, chloride and small organic osmolytes using plasma membrane channels and transporters. This generates osmotic gradients, which drive water in and out of cells. Key players in this process are volume-regulated anion channels (VRACs), the composition of which has recently been identified and shown to encompass LRRC8 heteromers. VRACs also transport metabolites and drugs and function in extracellular signal transduction, apoptosis and anticancer drug resistance.
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Affiliation(s)
- Thomas J Jentsch
- Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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36
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Sato-Numata K, Numata T, Inoue R, Okada Y. Distinct pharmacological and molecular properties of the acid-sensitive outwardly rectifying (ASOR) anion channel from those of the volume-sensitive outwardly rectifying (VSOR) anion channel. Pflugers Arch 2016; 468:795-803. [DOI: 10.1007/s00424-015-1786-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/23/2015] [Accepted: 12/28/2015] [Indexed: 11/24/2022]
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37
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Akita T, Kumada T, Yoshihara SI, Egea J, Yamagishi S. Ion channels, guidance molecules, intracellular signaling and transcription factors regulating nervous and vascular system development. J Physiol Sci 2015; 66:175-88. [PMID: 26507418 PMCID: PMC4752580 DOI: 10.1007/s12576-015-0416-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 09/30/2015] [Indexed: 01/13/2023]
Abstract
Our sophisticated thoughts and behaviors are based on the miraculous development of our complex nervous network system, in which many different types of proteins and signaling cascades are regulated in a temporally and spatially ordered manner. Here we review our recent attempts to grasp the principles of nervous system development in terms of general cellular phenomena and molecules, such as volume-regulated anion channels, intracellular Ca2+ and cyclic nucleotide signaling, the Npas4 transcription factor and the FLRT family of axon guidance molecules. We also present an example illustrating that the same FLRT family may regulate the development of vascular networks as well. The aim of this review is to open up new vistas for understanding the intricacy of nervous and vascular system development.
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Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan.
| | - Tatsuro Kumada
- Department of Occupational Therapy, Faculty of Health and Medical Sciences, Tokoha University, 1230 Miyakoda-cho, Kita-ku, Hamamatsu, Shizuoka, 431-2102, Japan
| | - Sei-ichi Yoshihara
- Laboratory for Molecular Biology of Neural System, Advanced Medical Research Center, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Joaquim Egea
- Molecular and Developmental Neurobiology Group, Biomedical Research Institute of Lleida (IRBLleida), University of Lleida, 25198, Lleida, Spain
| | - Satoru Yamagishi
- Department of Anatomy and Neuroscience, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
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38
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Affiliation(s)
- Philipp Burow
- a Julius-Bernstein-Institute for Physiology ; Martin-Luther-University Halle ; D-Halle/Saale , Germany
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Brignone MS, Lanciotti A, Camerini S, De Nuccio C, Petrucci TC, Visentin S, Ambrosini E. MLC1 protein: a likely link between leukodystrophies and brain channelopathies. Front Cell Neurosci 2015; 9:66. [PMID: 25883547 PMCID: PMC4381631 DOI: 10.3389/fncel.2015.00106] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/09/2015] [Indexed: 01/12/2023] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLCs) disease is a rare inherited, autosomal recessive form of childhood-onset spongiform leukodystrophy characterized by macrocephaly, deterioration of motor functions, epileptic seizures and mental decline. Brain edema, subcortical fluid cysts, myelin and astrocyte vacuolation are the histopathological hallmarks of MLC. Mutations in either the MLC1 gene (>75% of patients) or the GlialCAM gene (<20% of patients) are responsible for the disease. Recently, the GlialCAM adhesion protein was found essential for the membrane expression and function of the chloride channel ClC-2 indicating MLC disease caused by mutation in GlialCAM as the first channelopathy among leukodystrophies. On the contrary, the function of MLC1 protein, which binds GlialCAM, its functional relationship with ClC-2 and the molecular mechanisms underlying MLC1 mutation-induced functional defects are not fully understood yet. The human MLC1 gene encodes a 377-amino acid membrane protein with eight predicted transmembrane domains which shows very low homology with voltage-dependent potassium (K+) channel subunits. The high expression of MLC1 in brain astrocytes contacting blood vessels and meninges and brain alterations observed in MLC patients have led to hypothesize a role for MLC1 in the regulation of ion and water homeostasis. Recent studies have shown that MLC1 establishes structural and/or functional interactions with several ion/water channels and transporters and ion channel accessory proteins, and that these interactions are affected by MLC1 mutations causing MLC. Here, we review data on MLC1 functional properties obtained in in vitro and in vivo models and discuss evidence linking the effects of MLC1 mutations to brain channelopathies.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Angela Lanciotti
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Serena Camerini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Chiara De Nuccio
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Tamara C Petrucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Sergio Visentin
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
| | - Elena Ambrosini
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità Rome, Italy
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40
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Cai S, Zhang T, Zhang D, Qiu G, Liu Y. Volume-sensitive chloride channels are involved in cisplatin treatment of osteosarcoma. Mol Med Rep 2014; 11:2465-70. [PMID: 25503821 PMCID: PMC4337627 DOI: 10.3892/mmr.2014.3068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 11/14/2014] [Indexed: 01/23/2023] Open
Abstract
Chemotherapy is the most common therapeutic strategy used to treat osteosarcoma. The present study aimed to investigate the effects of functionally activated chloride channels on cisplatin-induced apoptosis of MG-63 human osteosarcoma cells. An MTT assay and flow cytometry were used to detect proliferation and apoptosis of the cells, respectively. Live cell imaging was used to detect volume changes in response to treatment with cisplatin and/or chloride channel blockers. The effects of these treatments on chloride currents were also assayed using the patch-clamp technique. The results of the present study indicate that chloride channel blockers may suppress cisplatin-induced apoptosis. The MG-63 cells cultured with cisplatin demonstrated an apoptotic volume decrease, as well as suppression of cell proliferation; which were reversed by co-treatment with chloride channel blockers. These results suggest that cisplatin may activate chloride channels, and that channel activation is an early signal in the pathways that lead to cisplatin-induced apoptosis and inhibition of proliferation in MG-63 cells. In conclusion, these results indicate that chloride channels have an important role in cisplatin treatment of osteosarcoma.
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Affiliation(s)
- Siyi Cai
- Department of Orthopedics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100032, P.R. China
| | - Tao Zhang
- Department of Internal Medicine, First Affiliated Hospital of Jinan University, Guangzhou, Guangdong 510630, P.R. China
| | - Dandan Zhang
- Department of Histology and Embryology, Medical College of Jinan University; Guangzhou, Guangdong 510632, P.R. China
| | - Guixing Qiu
- Department of Orthopedics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100032, P.R. China
| | - Yong Liu
- Department of Orthopedics, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100032, P.R. China
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Activation of volume-sensitive outwardly rectifying chloride channel by ROS contributes to ER stress and cardiac contractile dysfunction: involvement of CHOP through Wnt. Cell Death Dis 2014; 5:e1528. [PMID: 25412307 PMCID: PMC4260737 DOI: 10.1038/cddis.2014.479] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/30/2014] [Accepted: 10/02/2014] [Indexed: 12/21/2022]
Abstract
Endoplasmic reticulum (ER) stress occurring in stringent conditions is critically involved in cardiomyocytes apoptosis and cardiac contractile dysfunction (CCD). However, the molecular machinery that mediates cardiac ER stress and subsequent cell death remains to be fully deciphered, which will hopefully provide novel therapeutic targets for these disorders. Here, we establish tunicamycin-induced model of cardiomyocyte ER stress, which effectively mimicks pathological stimuli to trigger CCD. Tunicamycin activates volume-sensitive outward rectifying Cl− currents. Blockade of the volume-sensitive outwardly rectifying (VSOR) Cl− channel by 4,4'-diisothiocya-natostilbene-2,2'-disulfonic acid (DIDS), a non-selective Cl− channel blocker, and 4-(2-butyl-6,7-dichlor-2-cyclopentyl-indan-1-on-5-yl) oxybutyric acid (DCPIB), a selective VSOR Cl− channel blocker, improves cardiac contractility, which correlates with suppressed ER stress through inhibiting the canonical GRP78/eIF2α/ATF4 and XBP1 pathways, and promotes survival of cardiomyocytes by inverting tunicamycin-induced decrease of Wnt through the CHOP pathway. VSOR activation of tunicamycin-treated cardiomyocytes is attributed to increased intracellular levels of reactive oxygen species (ROS). Our study demonstrates a pivotal role of ROS/VSOR in mediating ER stress and functional impairment of cardiomyocytes via the CHOP-Wnt pathway, and suggests the therapeutic values of VSOR Cl− channel blockers against ER stress-associated cardiac anomalies.
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Sun H, Niisato N, Inui T, Marunaka Y. Insulin is involved in transcriptional regulation of NKCC and the CFTR Cl(-) channel through PI3K activation and ERK inactivation in renal epithelial cells. J Physiol Sci 2014; 64:433-43. [PMID: 25239597 PMCID: PMC10717268 DOI: 10.1007/s12576-014-0338-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 08/31/2014] [Indexed: 01/26/2023]
Abstract
It is is well known that insulin stimulates glucose transport and epithelial Na(+) channel (ENaC)-mediated Na(+) reabsorption; however, the action of insulin on Cl(-) secretion is not fully understood. In this study, we investigated the action of insulin on Na(+)-K(+)-2Cl(-) cotransporter (NKCC)-mediated Cl(-) secretion in epithelial A6 cells. Interestingly, insulin treatment remarkably enhanced the forskolin-stimulated Cl(-) secretion associated with an increase in apical Cl(-) conductance by upregulating mRNA expression of both CFTR and NKCC, although insulin treatment alone had no effect on the basal Cl(-) secretion or apical Cl(-) conductance without forskolin application. We next elucidated a role of phosphoinositide 3-kinase (PI3K) in the insulin-induced enhancement of the Cl(-) secretion, since insulin actually activated PI3K, resulting in activation of Akt, a downstream molecule of PI3K. LY294002 (a PI3K inhibitor) reduced the Cl(-) secretion by suppressing mRNA expression of NKCC, whereas insulin still had a stimulatory action on mRNA expression of CFTR even in the presence of LY294002. On the other hand, we found that a MEK inhibitor (PD98059) further enhanced the insulin-stimulated CFTR mRNA expression and the Cl(-) secretion in forskolin-stimulated A6 cells and that insulin induced slight, transient activation of ERK followed by significant inactivation of ERK. These observations suggest that: (1) insulin respectively upregulates mRNA expression of NKCC and CFTR through activation of PI3K and inactivation of ERK; (2) insulin signals on mRNA expression of NKCC and CFTR are not enough to stimulate transepithelial Cl(-) secretion, but enhance the stimulatory action of cAMP on transepithelial Cl(-) secretion.
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Affiliation(s)
- Hongxin Sun
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
| | - Naomi Niisato
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
- Japan Institute for Food Education and Health, St. Agnes’ University, Kyoto, 602-8013 Japan
| | - Toshio Inui
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
- Saisei Mirai Clinics, Moriguchi, 570-0012 Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566 Japan
- Japan Institute for Food Education and Health, St. Agnes’ University, Kyoto, 602-8013 Japan
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43
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Giuliani C, Peri A. Effects of Hyponatremia on the Brain. J Clin Med 2014; 3:1163-77. [PMID: 26237597 PMCID: PMC4470176 DOI: 10.3390/jcm3041163] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/18/2014] [Accepted: 10/10/2014] [Indexed: 12/31/2022] Open
Abstract
Hyponatremia is a very common electrolyte disorder, especially in the elderly, and is associated with significant morbidity, mortality and disability. In particular, the consequences of acute hyponatremia on the brain may be severe, including permanent disability and death. Also chronic hyponatremia can affect the health status, causing attention deficit, gait instability, increased risk of falls and fractures, and osteoporosis. Furthermore, an overly rapid correction of hyponatremia can be associated with irreversible brain damage, which may be the result of the osmotic demyelination syndrome. This review analyzes the detrimental consequences of acute and chronic hyponatremia and its inappropriate correction on the brain and the underlying physiopathological mechanisms, with a particular attention to the less known in vivo and in vitro effects of chronic hyponatremia.
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Affiliation(s)
- Corinna Giuliani
- Endocrine Unit, Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence 50139, Italy.
| | - Alessandro Peri
- Endocrine Unit, Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence 50139, Italy.
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Huang W, Liu M, Zhu L, Liu S, Luo H, Ma L, Wang H, Lu R, Sun X, Chen L, Wang L. Functional expression of chloride channels and their roles in the cell cycle and cell proliferation in highly differentiated nasopharyngeal carcinoma cells. Physiol Rep 2014; 2:2/9/e12137. [PMID: 25214521 PMCID: PMC4270222 DOI: 10.14814/phy2.12137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
We previously demonstrated that the growth of the poorly differentiated nasopharyngeal carcinoma cells (CNE‐2Z) was more dependent on the activities of volume‐activated chloride channels than that of the normal nasopharyngeal epithelial cells (NP69‐SV40T). However, the activities and roles of such volume‐activated chloride channels in highly differentiated nasopharyngeal carcinoma cells (CNE‐1) are not clarified. In this study, it was found that a volume‐activated chloride current and a regulatory volume decrease (RVD) were induced by 47% hypotonic challenges. The current density and the capacity of RVD in the highly differentiated CNE‐1 cells were lower than those in the poorly differentiated CNE‐2Z cells, and higher than those in the normal cells (NP69‐SV40T). The chloride channel blockers, 5‐nitro‐2‐(3‐phenylpropylamino) benzoic acid (NPPB) and tamoxifen inhibited the current and RVD. Depletion of intracellular Cl− abolished the RVD. The chloride channel blockers reversibly inhibited cell proliferation in a concentration‐ and time‐dependent manner, and arrested cells at the G0/G1 phases, but did not change cell viability. The sensitivity of the three cell lines to the chloride channel blockers was different, with the highest in poorly differentiated cells (CNE‐2Z) and the lowest in the normal cells (NP69‐SV40T). ClC‐3 proteins were expressed in the three cells and distributed inside the cells as well as on the cell membrane. In conclusion, the highly differentiated nasopharyngeal carcinoma CNE‐1 cells functionally expressed the volume‐activated chloride channels, which may play important roles in controlling cell proliferation through modulating the cell cycle, and may be associated with cell differentiation. Chloride channels may be a potential target of anticancer therapy. In this paper, we demonstrated that the volume‐activated chloride channels were involved in regulating CNE‐1 cells proliferation and cell cycle progress. Thus, volume‐activated chloride channels may be a potential target of anticancer therapy.
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Affiliation(s)
- Weiyuan Huang
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
| | - Mei Liu
- Department of Pharmacology, Medical College, Jinan University, Guangzhou, China
| | - Linyan Zhu
- Department of Pharmacology, Medical College, Jinan University, Guangzhou, China
| | - Shanwen Liu
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
| | - Hai Luo
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
| | - Lianshun Ma
- Department of Pharmacology, Medical College, Jinan University, Guangzhou, China
| | - Haibo Wang
- Department of Pharmacology, Medical College, Jinan University, Guangzhou, China
| | - Ruiling Lu
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
| | - Xiaoxue Sun
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
| | - Lixin Chen
- Department of Pharmacology, Medical College, Jinan University, Guangzhou, China
| | - Liwei Wang
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
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Qiu Z, Dubin AE, Mathur J, Tu B, Reddy K, Miraglia LJ, Reinhardt J, Orth AP, Patapoutian A. SWELL1, a plasma membrane protein, is an essential component of volume-regulated anion channel. Cell 2014; 157:447-458. [PMID: 24725410 DOI: 10.1016/j.cell.2014.03.024] [Citation(s) in RCA: 416] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/24/2014] [Accepted: 03/18/2014] [Indexed: 12/23/2022]
Abstract
Maintenance of a constant cell volume in response to extracellular or intracellular osmotic changes is critical for cellular homeostasis. Activation of a ubiquitous volume-regulated anion channel (VRAC) plays a key role in this process; however, its molecular identity in vertebrates remains unknown. Here, we used a cell-based fluorescence assay and performed a genome-wide RNAi screen to find components of VRAC. We identified SWELL1 (LRRC8A), a member of a four-transmembrane protein family with unknown function, as essential for hypotonicity-induced iodide influx. SWELL1 is localized to the plasma membrane, and its knockdown dramatically reduces endogenous VRAC currents and regulatory cell volume decrease in various cell types. Furthermore, point mutations in SWELL1 cause a significant change in VRAC anion selectivity, demonstrating that SWELL1 is an essential VRAC component. These findings enable further molecular characterization of the VRAC channel complex and genetic studies for understanding the function of VRAC in normal physiology and disease.
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Affiliation(s)
- Zhaozhu Qiu
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA; Department of Molecular and Cellular Neuroscience, Howard Hughes Medical Institute, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adrienne E Dubin
- Department of Molecular and Cellular Neuroscience, Howard Hughes Medical Institute, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jayanti Mathur
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Buu Tu
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Kritika Reddy
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Loren J Miraglia
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Jürgen Reinhardt
- Novartis Institutes for Biomedical Research, Basel 4056, Switzerland
| | - Anthony P Orth
- Genomics Institute of the Novartis Research Foundation, San Diego, CA 92121, USA
| | - Ardem Patapoutian
- Department of Molecular and Cellular Neuroscience, Howard Hughes Medical Institute, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Yan Y, Ding Y, Ming B, Du W, Kong X, Tian L, Zheng F, Fang M, Tan Z, Gong F. Increase in hypotonic stress-induced endocytic activity in macrophages via ClC-3. Mol Cells 2014; 37:418-25. [PMID: 24850147 PMCID: PMC4044314 DOI: 10.14348/molcells.2014.0031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 04/01/2014] [Indexed: 12/26/2022] Open
Abstract
Extracellular hypotonic stress can affect cellular function. Whether and how hypotonicity affects immune cell function remains to be elucidated. Macrophages are immune cells that play key roles in adaptive and innate in immune reactions. The purpose of this study was to investigate the role and underlying mechanism of hypotonic stress in the function of bone marrow-derived macrophages (BMDMs). Hypotonic stress increased endocytic activity in BMDMs, but there was no significant change in the expression of CD80, CD86, and MHC class II molecules, nor in the secretion of TNF-α or IL-10 by BMDMs. Furthermore, the enhanced endocytic activity of BMDMs triggered by hypotonic stress was significantly inhibited by chloride channel-3 (ClC-3) siRNA. Our findings suggest that hypotonic stress can induce endocytosis in BMDMs and that ClC-3 plays a central role in the endocytic process.
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Affiliation(s)
- Yutao Yan
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
- Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Yu Ding
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Bingxia Ming
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Wenjiao Du
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Xiaoling Kong
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Li Tian
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Fang Zheng
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Min Fang
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Zheng Tan
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
| | - Feili Gong
- Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 4340030,
China
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47
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Voss FK, Ullrich F, Münch J, Lazarow K, Lutter D, Mah N, Andrade-Navarro MA, von Kries JP, Stauber T, Jentsch TJ. Identification of LRRC8 heteromers as an essential component of the volume-regulated anion channel VRAC. Science 2014; 344:634-8. [PMID: 24790029 DOI: 10.1126/science.1252826] [Citation(s) in RCA: 428] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Regulation of cell volume is critical for many cellular and organismal functions, yet the molecular identity of a key player, the volume-regulated anion channel VRAC, has remained unknown. A genome-wide small interfering RNA screen in mammalian cells identified LRRC8A as a VRAC component. LRRC8A formed heteromers with other LRRC8 multispan membrane proteins. Genomic disruption of LRRC8A ablated VRAC currents. Cells with disruption of all five LRRC8 genes required LRRC8A cotransfection with other LRRC8 isoforms to reconstitute VRAC currents. The isoform combination determined VRAC inactivation kinetics. Taurine flux and regulatory volume decrease also depended on LRRC8 proteins. Our work shows that VRAC defines a class of anion channels, suggests that VRAC is identical to the volume-sensitive organic osmolyte/anion channel VSOAC, and explains the heterogeneity of native VRAC currents.
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Affiliation(s)
- Felizia K Voss
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin
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Furukawa T, Yamada J, Akita T, Matsushima Y, Yanagawa Y, Fukuda A. Roles of taurine-mediated tonic GABAA receptor activation in the radial migration of neurons in the fetal mouse cerebral cortex. Front Cell Neurosci 2014; 8:88. [PMID: 24734001 PMCID: PMC3975117 DOI: 10.3389/fncel.2014.00088] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 03/10/2014] [Indexed: 11/15/2022] Open
Abstract
γ-Aminobutyric acid (GABA) depolarizes embryonic cerebrocortical neurons and continuous activation of the GABAA receptor (GABAAR) contributes to their tonic depolarization. Although multiple reports have demonstrated a role of GABAAR activation in neocortical development, including in migration, most of these studies have used pharmacological blockers. Herein, we performed in utero electroporation in GABA synthesis-lacking homozygous GAD67-GFP knock-in mice (GAD67GFP/GFP) to label neurons born in the ventricular zone. Three days after electroporation, there were no differences in the distribution of labeled cells between the genotypes. The dose–response properties of labeled cells to GABA were equivalent among genotypes. However, continuous blockade of GABAAR with the GABAAR antagonist SR95531 accelerated radial migration. This effect of GABAAR blockade in GAD67GFP/GFP mice suggested a role for alternative endogenous GABAAR agonists. Thus, we tested the role of taurine, which is derived from maternal blood but is abundant in the fetal brain. The taurine-evoked currents in labeled cells were mediated by GABAAR. Taurine uptake was blocked by a taurine transporter inhibitor, 2-(guanidino)ethanesulfonic acid (GES), and taurine release was blocked by a volume-sensitive anion channel blocker, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid, as examined through high-performance liquid chromatography. GES increased the extracellular taurine concentration and induced an inward shift of the holding current, which was reversed by SR95531. In a taurine-deficient mouse model, the GABAAR-mediated tonic currents were greatly reduced, and radial migration was accelerated. As the tonic currents were equivalent among the genotypes of GAD67-GFP knock-in mice, taurine, rather than GABA, might play a major role as an endogenous agonist of embryonic tonic GABAAR conductance, regulating the radial migration of neurons in the developing neocortex.
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Affiliation(s)
- Tomonori Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Junko Yamada
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan ; Department of Neurophysiology, Hirosaki University Graduate School of Medicine Hirosaki, Aomori, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yoshitaka Matsushima
- Department of Chemistry, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Gunma, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Shizuoka, Japan
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Stauber T, Weinert S, Jentsch TJ. Cell biology and physiology of CLC chloride channels and transporters. Compr Physiol 2013; 2:1701-44. [PMID: 23723021 DOI: 10.1002/cphy.c110038] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Proteins of the CLC gene family assemble to homo- or sometimes heterodimers and either function as Cl(-) channels or as Cl(-)/H(+)-exchangers. CLC proteins are present in all phyla. Detailed structural information is available from crystal structures of bacterial and algal CLCs. Mammals express nine CLC genes, four of which encode Cl(-) channels and five 2Cl(-)/H(+)-exchangers. Two accessory β-subunits are known: (1) barttin and (2) Ostm1. ClC-Ka and ClC-Kb Cl(-) channels need barttin, whereas Ostm1 is required for the function of the lysosomal ClC-7 2Cl(-)/H(+)-exchanger. ClC-1, -2, -Ka and -Kb Cl(-) channels reside in the plasma membrane and function in the control of electrical excitability of muscles or neurons, in extra- and intracellular ion homeostasis, and in transepithelial transport. The mainly endosomal/lysosomal Cl(-)/H(+)-exchangers ClC-3 to ClC-7 may facilitate vesicular acidification by shunting currents of proton pumps and increase vesicular Cl(-) concentration. ClC-3 is also present on synaptic vesicles, whereas ClC-4 and -5 can reach the plasma membrane to some extent. ClC-7/Ostm1 is coinserted with the vesicular H(+)-ATPase into the acid-secreting ruffled border membrane of osteoclasts. Mice or humans lacking ClC-7 or Ostm1 display osteopetrosis and lysosomal storage disease. Disruption of the endosomal ClC-5 Cl(-)/H(+)-exchanger leads to proteinuria and Dent's disease. Mouse models in which ClC-5 or ClC-7 is converted to uncoupled Cl(-) conductors suggest an important role of vesicular Cl(-) accumulation in these pathologies. The important functions of CLC Cl(-) channels were also revealed by human diseases and mouse models, with phenotypes including myotonia, renal loss of salt and water, deafness, blindness, leukodystrophy, and male infertility.
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Affiliation(s)
- Tobias Stauber
- Leibniz-Institut für Molekulare Pharmakologie FMP and Max-Delbrück-Centrum für Molekulare Medizin MDC, Berlin, Germany
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50
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Catacuzzeno L, Michelucci A, Sforna L, Aiello F, Sciaccaluga M, Fioretti B, Castigli E, Franciolini F. Identification of key signaling molecules involved in the activation of the swelling-activated chloride current in human glioblastoma cells. J Membr Biol 2013; 247:45-55. [PMID: 24240542 DOI: 10.1007/s00232-013-9609-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/14/2013] [Indexed: 12/17/2022]
Abstract
The swelling-activated chloride current (I Cl,Vol) is abundantly expressed in glioblastoma (GBM) cells, where it controls cell volume and invasive migration. The transduction pathway mediating I Cl,Vol activation in GBM cells is, however, poorly understood. By means of pharmacological and electrophysiological approaches, on GL-15 human GBM cells we found that I Cl,Vol activation by hypotonic swelling required the activity of a U73122-sensitive phospholipase C (PLC). I Cl,Vol activation could also be induced by the membrane-permeable diacylglycerol (DAG) analog OAG. In contrast, neither calcium (Ca(2+)) chelation by BAPTA-AM nor changes in PKC activity were able to affect I Cl,Vol activation by hypotonic swelling. We further found that R59022, an inhibitor of diacylglycerol kinase (DGK), reverted I Cl,Vol activation, suggesting the involvement of phosphatidic acid. In addition, I Cl,Vol activation required the activity of a EHT1864-sensitive Rac1 small GTPase and the resulting actin polymerization, as I Cl,Vol activation was prevented by cytochalasin B. We finally show that I Cl,Vol can be activated by the promigratory fetal calf serum in a PLC- and DGK-dependent manner. This observation is potentially relevant because blood serum can likely come in contact with glioblastoma cells in vivo as a result of the tumor-related partial breakdown of the blood-brain barrier. Given the relevance of I Cl,Vol in GBM cell volume regulation and invasiveness, the several key signaling molecules found in this study to be involved in the activation of the I Cl,Vol may represent potential therapeutic targets against this lethal cancer.
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Affiliation(s)
- Luigi Catacuzzeno
- Dipartimento di Biologia Cellulare e Ambientale, Universita' di Perugia, Via Pascoli 1, 06123, Perugia, Italy,
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