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Nemeth Z, Hildebrandt E, Parsa N, Fleming AB, Wasson R, Pittman K, Bell X, Granger JP, Ryan MJ, Drummond HA. Epithelial sodium channels in macrophage migration and polarization: role of proinflammatory cytokines TNFα and IFNγ. Am J Physiol Regul Integr Comp Physiol 2022; 323:R763-R775. [PMID: 36189990 PMCID: PMC9639769 DOI: 10.1152/ajpregu.00207.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/13/2022] [Accepted: 09/26/2022] [Indexed: 11/22/2022]
Abstract
Migration of monocytes-macrophages plays an important role in phagocytosis of pathogens and cellular debris in a variety of pathophysiological conditions. Although epithelial Na+ channels (ENaCs) are required for normal migratory responses in other cell types, their role in macrophage migration signaling is unknown. To address this possibility, we determined whether ENaC message is present in several peripheral blood monocyte cell populations and tissue-resident macrophages in healthy humans using the Human Protein Atlas database (www.proteinatlas.org) and the mouse monocyte cell line RAW 264.7 using RT-PCR. We then determined that selective ENaC inhibition with amiloride inhibited chemotactic migration (∼50%), but not phagocytosis, of the mouse monocyte-macrophage cell line RAW 264.7. Furthermore, we generated a cell line stably expressing an NH2-terminal truncated αENaC to interrupt normal channel trafficking and found it suppressed migration. Prolonged exposure (48 h) of RAW 264.7 cells to proinflammatory cytokines interferon γ (IFNγ) and/or tumor necrosis factor α (TNFα) inhibited RAW 264.7 migration and abolished the amiloride (1 µM)-sensitive component of migration, a finding consistent with ENaC downregulation. To determine if proinflammatory cytokines regulate αENaC protein expression, cells were exposed to proinflammatory cytokines IFNγ (10 ng/mL, last 48 h) and TNFα (10 ng/mL, last 24 h). By Western blot analysis, we found whole cell αENaC protein is reduced ≥50%. Immunofluorescence demonstrated heterogeneous αENaC inhibition. Finally, we found that overnight exposure to amiloride stimulated morphological changes and increased polarization marker expression. Our findings suggest that ENaC may be a critical molecule in macrophage migration and polarization.
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Affiliation(s)
- Zoltan Nemeth
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Emily Hildebrandt
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Nicholas Parsa
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Adam B Fleming
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Robert Wasson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Katarina Pittman
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xavier Bell
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael J Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Xiu M, Li L, Li Y, Gao Y. An update regarding the role of WNK kinases in cancer. Cell Death Dis 2022; 13:795. [PMID: 36123332 PMCID: PMC9485243 DOI: 10.1038/s41419-022-05249-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 01/23/2023]
Abstract
Mammalian WNK kinases (WNKs) are serine/threonine kinases that contain four members, WNK1-4. They function to maintain ion homeostasis and regulate blood pressure in mammals. Recent studies have revealed that the dysregulation of WNKs contributes to tumor growth, metastasis, and angiogenesis through complex mechanisms, especially through phosphorylating kinase substrates SPS1-related proline/alanine-rich kinase (SPAK) and oxidative stress-responsive kinase 1 (OSR1). Here, we review and discuss the relationships between WNKs and several key factors/biological processes in cancer, including ion channels, cation chloride cotransporters, sodium bicarbonate cotransporters, signaling pathways, angiogenesis, autophagy, and non-coding RNAs. In addition, the potential drugs for targeting WNK-SPAK/OSR1 signaling have also been discussed. This review summarizes and discusses knowledge of the roles of WNKs in cancer, which provides a comprehensive reference for future studies.
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Affiliation(s)
- Mengxi Xiu
- grid.24516.340000000123704535Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, 200120 Shanghai, China
| | - Li Li
- grid.24516.340000000123704535Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, 200120 Shanghai, China
| | - Yandong Li
- grid.24516.340000000123704535Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, 200120 Shanghai, China
| | - Yong Gao
- grid.24516.340000000123704535Department of Oncology, Shanghai East Hospital, Tongji University School of Medicine, 200120 Shanghai, China
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Lu Y, Stec DE, Liu R, Ryan M, Drummond HA. βENaC and ASIC2 associate in VSMCs to mediate pressure-induced constriction in the renal afferent arteriole. Am J Physiol Renal Physiol 2022; 322:F498-F511. [PMID: 35285274 PMCID: PMC8977180 DOI: 10.1152/ajprenal.00003.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/17/2022] [Accepted: 03/03/2022] [Indexed: 11/22/2022] Open
Abstract
In independent studies, our laboratory has shown the importance of the degenerin proteins β-epithelial Na+ channel (βENaC) and acid-sensing ion channel 2 (ASIC2) in pressure-induced constriction (PIC) in renal interlobar arteries. Most, but not all, of the PIC response is abolished in mice lacking normal levels of βENaC or in ASIC2-null mice, indicating that the functions of βENaC and ASIC2 cannot fully compensate for the loss of the other. Degenerin proteins are known to associate and form heteromeric channels in expression systems, but whether they interact biochemically and functionally in vascular smooth muscle cells is unknown. We hypothesized that βENaC and ASIC2 interact to mediate PIC responses in renal vessels. To address this possibility, we 1) used biochemical approaches to show that βENaC associates into high-molecular-weight complexes and immunoprecipitants with ASIC2 in vascular smooth muscle cells and then 2) examined PIC in renal afferent arterioles in mice lacking normal levels of βENaC (βENaCm/m) or/and ASIC2 (ASIC2-/-) using the isolated afferent arteriole-attached glomerulus preparation. We found that the sensitivity of the PIC response (slope of the relationship between intraluminal pressure and percent myogenic tone) decreased to 26%, 27%, and -8% of wild-type controls in ASIC2-/-, βENaCm/m, and ASIC2-/-/βENaCm/m groups, respectively, suggesting that the PIC response was totally abolished in mice deficient in both ASIC2 and βENaC. Surprisingly, we found that resting internal diameters were 20-30% lower (60 mmHg, Ca2+ free) in ASIC2-/-/βENaCm/m (11.3 ± 0.5 µm) mice compared with control (14.4 ± 0.6 µm, P = 0.0007, independent two-tailed t test) or singly modified (15.7 ± 1.0 to 16.3 ± 1.1 µm) mice, suggesting compensatory vasoconstriction or remodeling. We then examined mean arterial blood pressure (MAP) using radiotelemetry and glomerular injury using histological examination of renal sections. We found that 24-h MAP was mildly elevated (+8 mmHg) in ASIC2-/-/βENaCm/m mice versus wild-type controls and the glomerular injury score was modestly increased by 38%. These findings demonstrate that myogenic constriction in afferent arterioles is dependent on normal expression of βENaC and ASIC2 and that mice lacking normal levels of ASIC2 and βENaC have mild renal injury and increased MAP.NEW & NOTEWORTHY Transmission of systemic blood pressure to delicate renal microvessels is a primary determinant of vascular injury in chronic kidney disease progression to end-stage renal disease. Here, we identified two degenerin family members, with an evolutionary link to mechanosensing, that interact biochemically and functionally to regulate systemic blood pressure and renal injury. Thus, degenerin proteins may serve as a target for the development of therapies to prevent or delay renal disease progression.
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Affiliation(s)
- Yan Lu
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - David E Stec
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, University of South Florida, College of Medicine, Tampa, Florida
| | - Michael Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Heather A Drummond
- Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular Renal Research, University of Mississippi Medical Center, Jackson, Mississippi
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Ion Channel Involvement in Tumor Drug Resistance. J Pers Med 2022; 12:jpm12020210. [PMID: 35207698 PMCID: PMC8878471 DOI: 10.3390/jpm12020210] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 01/28/2022] [Accepted: 02/02/2022] [Indexed: 11/30/2022] Open
Abstract
Over 90% of deaths in cancer patients are attributed to tumor drug resistance. Resistance to therapeutic agents can be due to an innate property of cancer cells or can be acquired during chemotherapy. In recent years, it has become increasingly clear that regulation of membrane ion channels is an important mechanism in the development of chemoresistance. Here, we review the contribution of ion channels in drug resistance of various types of cancers, evaluating their potential in clinical management. Several molecular mechanisms have been proposed, including evasion of apoptosis, cell cycle arrest, decreased drug accumulation in cancer cells, and activation of alternative escape pathways such as autophagy. Each of these mechanisms leads to a reduction of the therapeutic efficacy of administered drugs, causing more difficulty in cancer treatment. Thus, targeting ion channels might represent a good option for adjuvant therapies in order to counteract chemoresistance development.
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Nemeth Z, Ryan MJ, Granger JP, Drummond HA. Expression of Exogenous Epithelial Sodium Channel Beta Subunit in the Mouse Middle Cerebral Artery Increases Pressure-Induced Constriction. Am J Hypertens 2021; 34:1227-1235. [PMID: 34161569 PMCID: PMC9526803 DOI: 10.1093/ajh/hpab098] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/18/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Pressure-induced constriction (PIC) is inherent to small arteries and arterioles, in which intraluminal pressure-induced vascular smooth muscle cell stretch elicits vasoconstriction. Degenerin (Deg) proteins, such as beta-epithelial Na+ channel (βENaC), have been studied in the PIC response because they are evolutionarily linked to known mechanosensors. While loss of Deg function phenotypes are plentiful, a gain-of-function phenotype has not been studied. The aim of this study was to determine if expression of exogenous βENaC in the isolated middle cerebral artery (MCA) enhances the PIC response. METHODS Isolated MCA segments from female mice (24 weeks, n = 5) were transfected with enhanced green fluorescent protein-βENaC (EGFP-βENaC) or with EGFP alone, incubated overnight at 37 °C, then studied in a pressure myograph. RESULTS Mechanical/morphological properties and vasoconstrictor responses to KCl and phenylephrine were identical in EGFP-βENaC and EGFP MCAs. In contrast, PIC responses were greater in EGFP-βENaC segments with ~2-fold greater peak myogenic tone. CONCLUSIONS These data confirm previous findings that βENaC is critical in the PIC response. These data provide proof-of-concept that upregulating βENaC can enhance PIC responses and lay the foundation to test the hypothesis that inflammation-mediated downregulation of βENaC contributes to cerebrovascular dysfunction.
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Affiliation(s)
- Zoltan Nemeth
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Michael J Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
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Zhang J, Yuan HK, Chen S, Zhang ZR. Detrimental or beneficial: Role of endothelial ENaC in vascular function. J Cell Physiol 2021; 237:29-48. [PMID: 34279047 DOI: 10.1002/jcp.30505] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 12/19/2022]
Abstract
In the past, it was believed that the expression of the epithelial sodium channel (ENaC) was restricted to epithelial tissues, such as the distal nephron, airway, sweat glands, and colon, where it is critical for sodium homeostasis. Over the past two decades, this paradigm has shifted due to the finding that ENaC is also expressed in various nonepithelial tissues, notably in vascular endothelial cells. In this review, the recent findings of the expression, regulation, and function of the endothelial ENaC (EnNaC) are discussed. The expression of EnNaC subunits is reported in a variety of endothelial cell lines and vasculatures, but this is controversial across different species and vessels and is not a universal finding in all vascular beds. The expression density of EnNaC is very faint compared to ENaC in the epithelium. To date, little is known about the regulatory mechanism of EnNaC. Through it can be regulated by aldosterone, the detailed downstream signaling remains elusive. EnNaC responds to increased extracellular sodium with the feedforward activation mechanism, which is quite different from the Na+ self-inhibition mechanism of ENaC. Functionally, EnNaC was shown to be a determinant of cellular mechanics and vascular tone as it can sense shear stress, and its activation or insertion into plasma membrane causes endothelial stiffness and reduced nitric oxide production. However, in some blood vessels, EnNaC is essential for maintaining the integrity of endothelial barrier function. In this context, we discuss the possible reasons for the distinct role of EnNaC in vasculatures.
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Affiliation(s)
- Jun Zhang
- School of Biomedical Sciences and Li Ka Shing Institute of Health Science, The Chinese University of Hong Kong, Hong Kong, China
| | - Hui-Kai Yuan
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Shuo Chen
- Department of Biopharmaceutical Sciences, School of Pharmacy, Harbin Medical University (Daqing), Daqing, China
| | - Zhi-Ren Zhang
- Departments of Pharmacy and Cardiology, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Heilongjiang Key Laboratory for Metabolic Disorder & Cancer Related Cardiovascular Diseases, NHC Key Laboratory of Cell Transplantation, Harbin Medical University & Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
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Duncan JW, Nemeth Z, Hildebrandt E, Granger JP, Ryan MJ, Drummond HA. Interleukin-17 induces hypertension but does not impair cerebrovascular function in pregnant rats. Pregnancy Hypertens 2021; 24:50-57. [PMID: 33677419 PMCID: PMC8159853 DOI: 10.1016/j.preghy.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 01/20/2021] [Accepted: 02/16/2021] [Indexed: 11/24/2022]
Abstract
Preeclampsia affects 5-8% of pregnancies and is characterized by hypertension, placental ischemia, neurological impairment, and an increase in circulating inflammatory cytokines, including Interleukin-17 (IL17). While placental ischemia has also been shown to impair cerebrovascular function, it is not known which placental-associated factor(s) drive this effect. The purpose of this study was to examine the effects of IL17 on cerebrovascular function during pregnancy. To achieve this goal, pregnant rats were infused with either IL17 (150 pg/day, 5 days, osmotic minipump), or vehicle (saline/0.7% BSA osmotic minipump) starting at gestational day (GD) 14. On GD 19, the cerebral blood flow (CBF) response to increases in mean arterial pressure (MAP) was measured in vivo, and myogenic constrictor responses of the middle cerebral artery (MCA) were assessed ex vivo. IL17 increased MAP but impaired CBF responses only at the highest arterial pressure measured (190 mmHg). Myogenic constrictor responses overall were mostly unaffected by IL17 infusion; however, the intraluminal pressure at which peak myogenic tone was generated was lower in the IL17 infused group (120 vs 165 mm Hg), suggesting maximal tone is exerted at lower intraluminal pressures in IL17-treated pregnant rats. Consistent with the lack of substantial change in overall myogenic responsiveness, there was no difference in cerebral vessel expression of putative mechanosensitive protein βENaC, but a tendency towards a decrease in ASIC2 (p = 0.067) in IL17 rats. This study suggests that infusion of IL17 independent of other placental ischemia-associated factors is insufficient to recapitulate the features of impaired cerebrovascular function during placental ischemia. Further studies to examine of the role of other pro-inflammatory cytokines, individually or a combination, are necessary to determine mechanisms of cerebral vascular dysfunction during preeclampsia.
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Affiliation(s)
- Jeremy W Duncan
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39206, USA
| | - Zoltan Nemeth
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39206, USA
| | - Emily Hildebrandt
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39206, USA
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39206, USA
| | - Michael J Ryan
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39206, USA
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39206, USA.
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Ware AW, Harris JJ, Slatter TL, Cunliffe HE, McDonald FJ. The epithelial sodium channel has a role in breast cancer cell proliferation. Breast Cancer Res Treat 2021; 187:31-43. [PMID: 33630195 DOI: 10.1007/s10549-021-06133-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 02/05/2021] [Indexed: 01/22/2023]
Abstract
PURPOSE Breast cancer is the most common cancer affecting women worldwide with half a million associated deaths annually. Despite a huge global effort, the pathways of breast cancer progression are not fully elucidated. Ion channels have recently emerged as novel regulators of cancer cell proliferation and metastasis. The epithelial sodium channel, ENaC, made up of α, β and γ subunits is well known for its role in Na+ reabsorption in epithelia, but a number of novel roles for ENaC have been described, including potential roles in cancer. A role for ENaC in breast cancer, however, has yet to be described. Therefore, the effects of ENaC level and activity on breast cancer proliferation were investigated. METHODS Through the publicly available SCAN-B dataset associations between αENaC mRNA expression and breast cancer subtypes, proliferation markers and epithelial-mesenchymal transition markers (EMT) were assessed. αENaC expression, through overexpression or siRNA-mediated knockdown, and activity, through the ENaC-specific inhibitor amiloride, were altered in MCF7, T47D, BT549, and MDAMB231 breast cancer cells. MTT and EdU cell proliferation assays were used to determine the effect of these manipulations on breast cancer cell proliferation. RESULTS High αENaC mRNA expression was associated with less aggressive and less proliferative breast cancer subtypes and with reduced expression of proliferation markers. Decreased αENaC expression or activity, in the mesenchymal breast cancer cell lines BT549 and MDAMB231, increased breast cancer cell proliferation. Conversely, increased αENaC expression decreased breast cancer cell proliferation. CONCLUSION αENaC expression is associated with a poor prognosis in breast cancer and is a novel regulator of breast cancer cell proliferation. Taken together, these results identify ENaC as a potential future therapeutic target.
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Affiliation(s)
- Adam W Ware
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Joshua J Harris
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Tania L Slatter
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Heather E Cunliffe
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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Interleukin-17 Reduces βENaC via MAPK Signaling in Vascular Smooth Muscle Cells. Int J Mol Sci 2020; 21:ijms21082953. [PMID: 32331392 PMCID: PMC7215799 DOI: 10.3390/ijms21082953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/08/2020] [Accepted: 04/14/2020] [Indexed: 11/23/2022] Open
Abstract
Degenerin proteins, such as the beta epithelial Na+ channel (βENaC), are essential in the intracellular signaling of pressure-induced constriction, an important vascular smooth muscle cell (VSMC) function. While certain cytokines reduce ENaC protein in epithelial tissue, it is unknown if interleukin-17 (IL-17), a potent pro-inflammatory cytokine, directly mediates changes in membrane-associated βENaC in VSMCs. Therefore, we tested the hypothesis that exposure to IL-17 reduces βENaC in VSMCs through canonical mitogen-activated protein kinase (MAPK) signaling pathways. We treated cultured rat VSMCs (A10 cell line) with IL-17 (1–100 ng/mL) for 15 min to 16 h and measured expression of βENaC, p38MAPK, c-jun kinase (JNK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB). IL-17 reduced βENaC protein expression in a concentration-dependent fashion and increased phosphorylation of p38MAPK by 15 min and JNK by 8 h. NFκB was unaffected by IL-17 in VSMCs. IL-17 treatment reduced VSMC viability but had no effect on cell death. To determine the underlying signaling pathway involved in this response, VSMCs were treated before and during IL-17 exposure with p38MAPK or JNK inhibitors. We found that JNK blockade prevented IL-17-mediated βENaC protein suppression. These data demonstrate that the pro-inflammatory cytokine IL-17 regulates VSMC βENaC via canonical MAPK signaling pathways, raising the possibility that βENaC-mediated loss of VSMC function may occur in inflammatory disorders.
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Baldin JP, Barth D, Fronius M. Epithelial Na + Channel (ENaC) Formed by One or Two Subunits Forms Functional Channels That Respond to Shear Force. Front Physiol 2020; 11:141. [PMID: 32256376 PMCID: PMC7090232 DOI: 10.3389/fphys.2020.00141] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/11/2020] [Indexed: 12/19/2022] Open
Abstract
Canonical epithelial sodium channels (ENaCs) are heterotrimers formed by α, β, and γ ENaC subunits in vertebrates and belong to the Degenerin/ENaC family of proteins. Proteins from this family form mechanosensitive channels throughout the animal kingdom. Activity of canonical ENaC is regulated by shear force (SF) mediating Na+ absorption in the kidney and vascular tone of arteries. Expression analysis suggests that non-canonical ENaC, formed by single or only two subunits, exist in certain tissues, but it is unknown if these channels respond to SF. α, β, γ, and δ ENaC subunits were expressed either alone or in combinations of two subunits in Xenopus oocytes. Amiloride-sensitive currents and the responses to SF were assessed using two-electrode voltage clamp recordings. With the exception of γ ENaC, all homomeric channels provided amiloride-sensitive currents and responded to SF applied via a fluid stream directed onto the oocytes. Channels containing two subunits were also activated by SF. Here, the presence of the γ ENaC subunit when co-expressed with α or δ augmented the SF response in comparison to the αβγ/δβγ ENaC. Overall, we provide evidence that non-canonical ENaC can form channels that respond to SF. This supports a potential function of non-canonical ENaC as mechanosensors in epithelial, vascular, and sensory cells.
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Affiliation(s)
- Jan-Peter Baldin
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Daniel Barth
- Institute of Physiology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany
| | - Martin Fronius
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,HeartOtago, University of Otago, Dunedin, New Zealand
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Duncan JW, Younes ST, Hildebrandt E, Ryan MJ, Granger JP, Drummond HA. Tumor necrosis factor-α impairs cerebral blood flow in pregnant rats: role of vascular β-epithelial Na + channel. Am J Physiol Heart Circ Physiol 2020; 318:H1018-H1027. [PMID: 32167780 DOI: 10.1152/ajpheart.00744.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Preeclampsia is a pregnancy-related disorder characterized by hypertension, vascular dysfunction and an increase in circulating inflammatory factors including the cytokine, tumor necrosis factor-α (TNF-α). Studies have shown that placental ischemia is associated with 1) increased circulating TNF-α, 2) attenuated pressure-induced cerebral vascular tone, and 3) suppression of β-epithelial Na+ channel (βENaC) protein in cerebral vessels. In addition to its role in epithelial Na+ and water transport, βENaC is an essential signaling element in transduction of pressure-induced (aka "myogenic") constriction, a critical mechanism of blood flow autoregulation. While cytokines inhibit expression of certain ENaC proteins in epithelial tissue, it is unknown if the increased circulating TNF-α associated with placental ischemia mediates the loss of cerebrovascular βENaC and cerebral blood flow regulation. Therefore, the purpose of this study was to test the hypothesis that increasing plasma TNF-α in normal pregnant rats reduces cerebrovascular βENaC expression and impairs cerebral blood flow (CBF) regulation. In vivo TNF-α infusion (200 ng/day, 5 days) inhibited cerebrovascular expression of βENaC and impaired CBF regulation in pregnant rats. To determine the direct effects of TNF-α and underlying pathways mediating vascular smooth muscle cell βENaC reduction, we exposed cultured VSMCs (A10 cell line) to TNF-α (1-100 ng/mL) for 16-24 h. TNF-α reduced βENaC protein expression in a concentration-dependent fashion from 0.1 to 100 ng/mL, without affecting cell death. To assess the role of canonical MAPK signaling in this response, VSMCs were treated with p38MAPK or c-Jun kinase (JNK) inhibitors in the presence of TNF-α. We found that both p38MAPK and JNK blockade prevented TNF-α-mediated βENaC protein suppression. These data provide evidence that disorders associated with increased circulating TNF-α could lead to impaired cerebrovascular regulation, possibly due to reduced βENaC-mediated vascular function.NEW & NOTEWORTHY This manuscript identifies TNF-α as a possible placental-derived cytokine that could be involved in declining cerebrovascular health observed in preeclampsia. We found that infusion of TNF-α during pregnancy impaired cerebral blood flow control in rats at high arterial pressures. We further discovered that cerebrovascular β-epithelial sodium channel (βENaC) protein, a degenerin protein involved in mechanotransduction, was reduced by TNF-α in pregnant rats, indicating a potential link between impaired blood flow and this myogenic player. We next examined this effect in vitro using a rat vascular smooth muscle cell line. TNF-α reduced βENaC through canonical MAPK-signaling pathways and was not dependent on cell death. This study demonstrates the pejorative effects of TNF-α on cerebrovascular function during pregnancy and warrants future investigations to study the role of cytokines on vascular function during pregnancy.
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Affiliation(s)
- Jeremy W Duncan
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Subhi Talal Younes
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Emily Hildebrandt
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael J Ryan
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Chambers L, Dorrance AM. Regulation of ion channels in the microcirculation by mineralocorticoid receptor activation. CURRENT TOPICS IN MEMBRANES 2020; 85:151-185. [PMID: 32402638 DOI: 10.1016/bs.ctm.2020.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mineralocorticoid receptor (MR) has classically been studied in the renal epithelium for its role in regulating sodium and water balance and, subsequently, blood pressure. However, the MR also plays a critical role in the microvasculature by regulating ion channel expression and function. Activation of the MR by its endogenous agonist aldosterone results in translocation of the MR into the nucleus, where it can act as a transcription factor. Although most of the actions of the aldosterone can be attributed to its genomic activity though MR activation, it can also act by nongenomic mechanisms. Activation of this ubiquitous receptor increases the expression of epithelial sodium channels (ENaC) in both the endothelium and smooth muscle cells of peripheral and cerebral vessels. MR activation also regulates activity of calcium channels, calcium-activated potassium channels, and various transient receptor potential (TRP) channels. Modification of these ion channels results in a myriad of negative consequences, including impaired endothelium-dependent vasodilation, alterations in generation of myogenic tone, and increased inflammation and oxidative stress. Taken together, these studies demonstrate the importance of studying the impact of the MR on ion channel function in the vasculature. While research in this area has made advances in recent years, there are still many large gaps in knowledge that need to be filled. Crucial future directions of study include defining the molecular mechanisms involved in this interaction, as well as elucidating the potential sex differences that may exist, as these areas of understanding are currently lacking.
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Affiliation(s)
- Laura Chambers
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States.
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Blockade of Acid-Sensing Ion Channels Attenuates Recurrent Hypoglycemia-Induced Potentiation of Ischemic Brain Damage in Treated Diabetic Rats. Neuromolecular Med 2019; 21:454-466. [PMID: 31134484 DOI: 10.1007/s12017-019-08546-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/17/2019] [Indexed: 12/18/2022]
Abstract
Diabetes is a chronic metabolic disease and cerebral ischemia is a serious complication of diabetes. Anti-diabetic therapy mitigates this complication but increases the risk of exposure to recurrent hypoglycemia (RH). We showed previously that RH exposure increases ischemic brain damage in insulin-treated diabetic (ITD) rats. The present study evaluated the hypothesis that increased intra-ischemic acidosis in RH-exposed ITD rats leads to pronounced post-ischemic hypoperfusion via activation of acid-sensing (proton-gated) ion channels (ASICs). Streptozotocin-diabetic rats treated with insulin were considered ITD rats. ITD rats were exposed to RH for 5 days and were randomized into Psalmotoxin1 (PcTx1, ASIC1a inhibitor), APETx2 (ASIC3 inhibitor), or vehicle groups. Transient global cerebral ischemia was induced overnight after RH. Cerebral blood flow was measured using laser Doppler flowmetry. Ischemic brain injury in hippocampus was evaluated using histopathology. Post-ischemic hypoperfusion in RH-exposed rats was of greater extent than that in control rats. Inhibition of ASICs prevented RH-induced increase in the extent of post-ischemic hypoperfusion and ischemic brain injury. Since ASIC activation-induced store-operated calcium entry (SOCE) plays a role in vascular tone, next we tested if acidosis activates SOCE via activating ASICs in vascular smooth muscle cells (VSMCs). We observed that SOCE in VSMCs at lower pH is ASIC3 dependent. The results show the role of ASIC in post-ischemic hypoperfusion and increased ischemic damage in RH-exposed ITD rats. Understanding the pathways mediating exacerbated ischemic brain injury in RH-exposed ITD rats may help lower diabetic aggravation of ischemic brain damage.
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Downs CA, Johnson NM, Coca C, Helms MN. Angiotensin II regulates δ-ENaC in human umbilical vein endothelial cells. Microvasc Res 2018; 116:26-33. [DOI: 10.1016/j.mvr.2017.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/19/2017] [Accepted: 10/15/2017] [Indexed: 11/24/2022]
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15
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Zhang W, Bei M. Kcnh2 and Kcnj8 interactively regulate skin wound healing and regeneration. Wound Repair Regen 2016. [PMID: 26220146 DOI: 10.1111/wrr.12347] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Previous studies indicate that ion channels are mediators of bioelectricity promoting wound closure/regeneration in nonmammalian, lower vertebrate systems. The role of ion channels however in regeneration of wounds in mammalian systems that do not regenerate as adults is not yet defined. Using a mammalian model system that allows us to determine differentially expressed genes when skin regenerates and when skin does not regenerate after wound induction, we identified two potassium channels, kcnh2 and kcnj8, to be (1) differentially expressed between the two states and (2) highly expressed after wound induction at the nonregenerative state. We also found that kcnh2 small molecule inhibitor enhanced wound healing while kcnj8 small molecule inhibitor did not. In contrast, kcnj8 activator accelerated wound healing and even augmented the effect of kcnh2 inhibition. These results provide evidence for the first time that potassium channels may mediate skin wound healing and regeneration interactively.
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Affiliation(s)
- Wengeng Zhang
- Department of Surgery, Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.,Shriners Burns Hospital, Boston, Massachusetts
| | - Marianna Bei
- Department of Surgery, Center for Engineering in Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.,Shriners Burns Hospital, Boston, Massachusetts.,Center for Surgery, Innovation and Biotechnology, Massachusetts General Hospital, Boston, Massachusetts
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16
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Yu D, Davis RM, Aita M, Burns KA, Clapp PW, Gilmore RC, Chua M, O'Neal WK, Schlegel R, Randell SH, C Boucher R. Characterization of Rat Meibomian Gland Ion and Fluid Transport. Invest Ophthalmol Vis Sci 2016; 57:2328-43. [PMID: 27127933 PMCID: PMC4855829 DOI: 10.1167/iovs.15-17945] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Purpose We establish novel primary rat meibomian gland (MG) cell culture systems and explore the ion transport activities of the rat MG. Methods Freshly excised rat MG tissues were characterized as follows: (1) mRNA expression of selected epithelial ion channels/transporters were measured by RT-PCR, (2) localization of epithelial sodium channel (ENaC) mRNAs was performed by in situ hybridization, and (3) protein expression and localization of βENaC, the Na+/K+/Cl− cotransporter (NKCC), and the Na+/K+ ATPase were evaluated by immunofluorescence. Primary isolated rat MG cells were cocultured with 3T3 feeder cells and a Rho-associated kinase (ROCK) inhibitor (Y-27632) for expansion. Passaged rat MG cells were cultured as planar sheets under air-liquid interface (ALI) conditions for gene expression and electrophysiologic studies. Passaged rat MG cells also were cultured in matrigel matrices to form spheroids, which were examined ultrastructurally by transmission electron microscopy (TEM) and functionally using swelling assays. Results Expression of multiple ion channel/transporter genes was detected in rat MG tissues. β-ENaC mRNA and protein were localized more to MG peripheral acinar cells than central acinar cells or ductular epithelial cells. Electrophysiologic studies of rat MG cell planar cultures demonstrated functional sodium, chloride, and potassium channels, and cotransporters activities. Transmission electron microscopic analyses of rat MG spheroids revealed highly differentiated MG cells with abundant lysosomal lamellar bodies. Rat MG spheroids culture-based measurements demonstrated active volume regulation by ion channels. Conclusions This study demonstrates the presence and function of ion channels and volume transport by rat MG. Two novel primary MG cell culture models that may be useful for MG research were established.
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Affiliation(s)
- Dongfang Yu
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Richard M Davis
- Department of Ophthalmology, The University of North Carolina, Chapel Hill, North Carolina, United States
| | - Megumi Aita
- Neuroscience Center, The University of North Carolina, Chapel Hill, North Carolina, United States
| | - Kimberlie A Burns
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Phillip W Clapp
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Rodney C Gilmore
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Michael Chua
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Wanda K O'Neal
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Richard Schlegel
- Department of Pathology, Georgetown University Medical School, Washington District of Columbia, United States
| | - Scott H Randell
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Richard C Boucher
- Marsico Lung Institute/UNC Cystic Fibrosis Research Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
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The Epithelial Sodium Channel and the Processes of Wound Healing. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5675047. [PMID: 27493961 PMCID: PMC4963570 DOI: 10.1155/2016/5675047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/15/2016] [Indexed: 12/19/2022]
Abstract
The epithelial sodium channel (ENaC) mediates passive sodium transport across the apical membranes of sodium absorbing epithelia, like the distal nephron, the intestine, and the lung airways. Additionally, the channel has been involved in the transduction of mechanical stimuli, such as hydrostatic pressure, membrane stretch, and shear stress from fluid flow. Thus, in vascular endothelium, it participates in the control of the vascular tone via its activity both as a sodium channel and as a shear stress transducer. Rather recently, ENaC has been shown to participate in the processes of wound healing, a role that may also involve its activities as sodium transporter and as mechanotransducer. Its presence as the sole channel mediating sodium transport in many tissues and the diversity of its functions probably underlie the complexity of its regulation. This brief review describes some aspects of ENaC regulation, comments on evidence about ENaC participation in wound healing, and suggests possible regulatory mechanisms involved in this participation.
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Herbert LM, Nitta CH, Yellowhair TR, Browning C, Gonzalez Bosc LV, Resta TC, Jernigan NL. PICK1/calcineurin suppress ASIC1-mediated Ca2+ entry in rat pulmonary arterial smooth muscle cells. Am J Physiol Cell Physiol 2015; 310:C390-400. [PMID: 26702130 DOI: 10.1152/ajpcell.00091.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 12/16/2015] [Indexed: 11/22/2022]
Abstract
Acid-sensing ion channel 1 (ASIC1) contributes to Ca(2+) influx and contraction in pulmonary arterial smooth muscle cells (PASMC). ASIC1 binds the PDZ (PSD-95/Dlg/ZO-1) domain of the protein interacting with C kinase 1 (PICK1), and this interaction is important for the subcellular localization and/or activity of ASIC1. Therefore, we first hypothesized that PICK1 facilitates ASIC1-dependent Ca(2+) influx in PASMC by promoting plasma membrane localization. Using Duolink to determine protein-protein interactions and a biotinylation assay to assess membrane localization, we demonstrated that the PICK1 PDZ domain inhibitor FSC231 diminished the colocalization of PICK1 and ASIC1 but did not limit ASIC1 plasma membrane localization. Although stimulation of store-operated Ca(2+) entry (SOCE) greatly enhanced colocalization between ASIC1 and PICK1, both FSC231 and shRNA knockdown of PICK1 largely augmented SOCE. These data suggest PICK1 imparts a basal inhibitory effect on ASIC1 Ca(2+) entry in PASMC and led to an alternative hypothesis that PICK1 facilitates the interaction between ASIC1 and negative intracellular modulators, namely PKC and/or the calcium-calmodulin-activated phosphatase calcineurin. FSC231 limited PKC-mediated inhibition of SOCE, supporting a potential role for PICK1 in this response. Additionally, we found PICK1 inhibits ASIC1-mediated SOCE through an effect of calcineurin to dephosphorylate the channel. Furthermore, it appears PICK1/calcineurin-mediated regulation of SOCE opposes PKA phosphorylation and activation of ASIC1. Together our data suggest PKA and PICK1/calcineurin differentially regulate ASIC1-mediated SOCE and these modulatory complexes are important in determining downstream Ca(2+) signaling.
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Affiliation(s)
- Lindsay M Herbert
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Carlos H Nitta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Tracylyn R Yellowhair
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Carly Browning
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Laura V Gonzalez Bosc
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Thomas C Resta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
| | - Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
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Liu HB, Zhang J, Sun YY, Li XY, Jiang S, Liu MY, Shi J, Song BL, Zhao D, Ma HP, Zhang ZR. Dietary salt regulates epithelial sodium channels in rat endothelial cells: adaptation of vasculature to salt. Br J Pharmacol 2015; 172:5634-46. [PMID: 25953733 DOI: 10.1111/bph.13185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 04/03/2015] [Accepted: 04/26/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE The epithelial sodium channel (ENaC) is expressed in vascular endothelial cells and is a negative modulator of vasodilation. However, the role of endothelial ENaCs in salt-sensitive hypertension remains unclear. Here, we have investigated how endothelial ENaCs in Sprague-Dawley (SD) rats respond to high-salt (HS) challenge. EXPERIMENTAL APPROACH BP and plasma aldosterone levels were measured. We used patch-clamp technique to record ENaC activity in split-open mesenteric arteries (MAs). Western blot and Griess assay were used to detect expression of α-ENaCs, eNOS and NO. Vasorelaxation in second-order MAs was measured with wire myograph assays. KEY RESULTS Functional ENaCs were observed in endothelial cells and their activity was significantly decreased after 1 week of HS diet. After 3 weeks of HS diet, ENaC expression was also reduced. When either ENaC activity or expression was reduced, endothelium-dependent relaxation (EDR) of MAs, in response to ACh, was enhanced. This enhancement of EDR was mimicked by amiloride, a blocker of ENaCs. By contrast, HS diet significantly increased contractility of MAs, accompanied by decreased eNOS activity and NO levels. However, ACh-induced release of NO was much higher in MAs isolated from HS rats than those from NS rats. CONCLUSIONS AND IMPLICATIONS HS intake increased the BP of SD rats, but simultaneously enhanced EDR by reducing ENaC activity and expression due to feedback inhibition. Therefore, ENaCs may play an important role in endothelial cells allowing the vasculature to adapt to HS conditions.
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Affiliation(s)
- Hui-Bin Liu
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Jun Zhang
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Ying-Ying Sun
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Xin-Yuan Li
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Shuai Jiang
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Ming-Yu Liu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Jing Shi
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Bin-Lin Song
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Dan Zhao
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - He-Ping Ma
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Zhi-Ren Zhang
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
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Rooj AK, Liu Z, McNicholas CM, Fuller CM. Physical and functional interactions between a glioma cation channel and integrin-β1 require α-actinin. Am J Physiol Cell Physiol 2015; 309:C308-19. [PMID: 26108662 DOI: 10.1152/ajpcell.00036.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/17/2015] [Indexed: 11/22/2022]
Abstract
Major plasma membrane components of the tumor cell, ion channels, and integrins play crucial roles in metastasis. Glioma cells express an amiloride-sensitive nonselective cation channel composed of acid-sensing ion channel (ASIC)-1 and epithelial Na(+) channel (ENaC) α- and γ-subunits. Inhibition of this channel is associated with reduced cell migration and proliferation. Using the ASIC-1 subunit as a reporter for the channel complex, we found a physical and functional interaction between this channel and integrin-β1. Short hairpin RNA knockdown of integrin-β1 attenuated the amiloride-sensitive current, which was due to loss of surface expression of ASIC-1. In contrast, upregulation of membrane expression of integrin-β1 increased the surface expression of ASIC-1. The link between the amiloride-sensitive channel and integrin-β1 was mediated by α-actinin. Downregulation of α-actinin-1 or -4 attenuated the amiloride-sensitive current. Mutation of the putative binding site for α-actinin on the COOH terminus of ASIC-1 reduced the membrane localization of ASIC-1 and also resulted in attenuation of the amiloride-sensitive current. Our data suggest a novel interaction between the amiloride-sensitive glioma cation channel and integrin-β1, mediated by α-actinin. This interaction may form a mechanism by which channel activity can regulate glioma cell proliferation and migration.
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Affiliation(s)
- Arun K Rooj
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Zhiyong Liu
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Carmel M McNicholas
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Catherine M Fuller
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
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Li XM, Wang H, Zhu LL, Zhao RZ, Ji HL. Genes Regulating Epithelial Polarity Are Critical Suppressors of Esophageal Oncogenesis. J Cancer 2015; 6:694-700. [PMID: 26185530 PMCID: PMC4504104 DOI: 10.7150/jca.11709] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/05/2015] [Indexed: 02/06/2023] Open
Abstract
Esophageal cancer is an aggressive disease featured by early lymphatic and hematogenous dissemination, and is the sixth leading cause of cancer-related deaths worldwide. The proper formation of apicobasal polarity is essential for normal epithelium physiology and tissue homeostasis, while loss of polarity is a hallmark of cancer development including esophageal oncogenesis. In this review, we summarized the stages of esophageal cancer development associated with the loss or deregulation of epithelial cell apicobasal polarity. Loss of epithelial apicobasal polarity exerts an indispensable role in the initiation of esophageal oncogenesis, tumor progression, and the advancement of tumors from benign to malignant. In particular, we reviewed the involvement of several critical genes, including Lkb1, claudin-4, claudin-7, Par3, Lgl1, E-cadherin, and the Scnn1 gene family. Understanding the role of apicobasal regulators may lead to new paradigms for treatment of esophageal tumors, including improvement of prognostication, early diagnosis, and individually tailored therapeutic interventions in esophageal oncology.
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Affiliation(s)
- Xiu-Min Li
- 1. Center for Cancer Research, Xinxiang Medical University, Xinxiang Henan, 453003, China
| | - Hui Wang
- 2. Ontario Cancer Institute, Campbell Family Institute for Breast Cancer Research, University of Toronto, Toronto, Ontario, M5G 2M9, Canada
| | - Li-Li Zhu
- 1. Center for Cancer Research, Xinxiang Medical University, Xinxiang Henan, 453003, China
| | - Run-Zhen Zhao
- 3. Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, USA
| | - Hong-Long Ji
- 3. Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, USA ; 4. Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, USA
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Jeggle P, Smith ESJ, Stewart AP, Haerteis S, Korbmacher C, Edwardson JM. Atomic force microscopy imaging reveals the formation of ASIC/ENaC cross-clade ion channels. Biochem Biophys Res Commun 2015; 464:38-44. [PMID: 26032502 DOI: 10.1016/j.bbrc.2015.05.091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 05/28/2015] [Indexed: 01/02/2023]
Abstract
ASIC and ENaC are co-expressed in various cell types, and there is evidence for a close association between them. Here, we used atomic force microscopy (AFM) to determine whether ASIC1a and ENaC subunits are able to form cross-clade hybrid ion channels. ASIC1a and ENaC could be co-isolated from detergent extracts of tsA 201 cells co-expressing the two subunits. Isolated proteins were incubated with antibodies against ENaC and Fab fragments against ASIC1a. AFM imaging revealed proteins that were decorated by both an antibody and a Fab fragment with an angle of ∼120° between them, indicating the formation of ASIC1a/ENaC heterotrimers.
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Affiliation(s)
- Pia Jeggle
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Ewan St J Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Andrew P Stewart
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Silke Haerteis
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstrasse 6, 91054 Erlangen, Germany
| | - Christoph Korbmacher
- Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Waldstrasse 6, 91054 Erlangen, Germany
| | - J Michael Edwardson
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom.
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Yang Y, He G, Xu W, Liu X. ENaC mediates human extravillous trophblast cell line (HTR8/SVneo) invasion by regulating levels of matrix metalloproteinase 2 (MMP2). Placenta 2015; 36:587-93. [PMID: 25707741 DOI: 10.1016/j.placenta.2015.01.201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/12/2015] [Accepted: 01/28/2015] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Placenta dysfunction is thought to be the major etiological factor related to preeclampsia. The epithelial sodium channel (ENaC) has been localized in the apical plasma membrane of epithelia, mediating the active reabsorption of sodium in kidney, and be involved in the regulation of blood pressure. In previous studies, we found that the reduced expression of ENaC on placenta in preeclampsia patients. The aim of this study was to determine the role of MMP2 in the ENaC-induced trophoblast cell invasion ability, which is closely related to the occurrence of preeclampsia. METHODS Here we checked whether pregnancy related hormones human chorionic gonadotropin (HCG), prolactin and aldosterone could affect ENaC expression in the first trimester extravillous trophoblast cell line (HTR8/SVneo) by RT-PCR and Western blot. Cell invasion was studied by matrigel invasion assay. Tube formation assay was used to investigate the interaction between trophoblast cells and endothelial cells. The effects of ENaC on MMP2 were further determined by RT-PCR, western blot and gelatin zymography. RESULTS We demonstrated that HCG, prolactin and aldosterone could up-regulate the expression of αENaC in protein levels. Trophoblast cell invasion ability is stimulated when αENaC was up-regulated by aldosterone, and inhibited when ENaC was down-regulated by amiloride and αENaC specific RNAi (SiENA/ENaC). The interaction between HTR8/SVneo cells and HUVEC cells was enhanced when treated with aldosterone and weakened when treated with amiloride and SiRNA/ENaC. Amiloride and SiRNA/ENaC could inhibit MMP2 expression and activity. DISSCUTION Aldosterone induced ENaC activity is important for trophoblast cells invasion. The results also indicate that ENaC could mediate trophoblast cells invasion ability through regulating expression and activity of matrix metalloproteinase-2 (MMP2).
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Affiliation(s)
- Y Yang
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu 610041, China
| | - G He
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu 610041, China
| | - W Xu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu 610041, China; Joint Laboratory of Reproductive Medicine, Key Laboratory of BirthDefects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
| | - X Liu
- Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
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Jernigan NL. Smooth muscle acid-sensing ion channel 1: pathophysiological implication in hypoxic pulmonary hypertension. Exp Physiol 2015; 100:111-20. [DOI: 10.1113/expphysiol.2014.081612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/04/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Nikki L. Jernigan
- Vascular Physiology Group; Department of Cell Biology and Physiology; University of New Mexico Health Sciences Center; Albuquerque, NM 87131-0001 USA
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25
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George EM, Warrington JP, Spradley FT, Palei AC, Granger JP. The heme oxygenases: important regulators of pregnancy and preeclampsia. Am J Physiol Regul Integr Comp Physiol 2014; 307:R769-77. [PMID: 24898840 DOI: 10.1152/ajpregu.00132.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The heme oxygenase system has long been believed to act largely as a housekeeping unit, converting prooxidant free heme from heme protein degradation into the benign bilirubin for conjugation and safe excretion. In recent decades, however, heme oxygenases have emerged as important regulators of cardiovascular function, largely through the production of their biologically active metabolites: carbon monoxide, bilirubin, and elemental iron. Even more recently, a number of separate lines of evidence have demonstrated an important role for the heme oxygenases in the establishment and maintenance of pregnancy. Early preclinical and clinical studies have associated defects in the heme oxygenase with the obstetrical complication preeclampsia, as well as failure to establish adequate placental blood flow, an underlying mechanism of the disorder. Several recent preclinical studies have suggested, however, that the heme oxygenase system could serve as a valuable therapeutic tool for the management of preeclampsia, which currently has few pharmacological options. This review will summarize the role of heme oxygenases in pregnancy and highlight their potential in advancing the management of patients with preeclampsia.
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Affiliation(s)
- Eric M George
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi; and Department of Biochemistry, The University of Mississippi Medical Center, Jackson, Mississippi
| | - Junie P Warrington
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Frank T Spradley
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Ana C Palei
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Joey P Granger
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi; and
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Warrington JP, Coleman K, Skaggs C, Hosick PA, George EM, Stec DE, Ryan MJ, Granger JP, Drummond HA. Heme oxygenase-1 promotes migration and β-epithelial Na+ channel expression in cytotrophoblasts and ischemic placentas. Am J Physiol Regul Integr Comp Physiol 2014; 306:R641-6. [PMID: 24553299 DOI: 10.1152/ajpregu.00566.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Preeclampsia is thought to arise from inadequate cytotrophoblast migration and invasion of the maternal spiral arteries, resulting in placental ischemia and hypertension. Evidence suggests that altered expression of epithelial Na(+) channel (ENaC) proteins may be a contributing mechanism for impaired cytotrophoblast migration. ENaC activity is required for normal cytotrophoblast migration. Moreover, β-ENaC, the most robustly expressed placental ENaC message, is reduced in placentas from preeclamptic women. We recently demonstrated that heme oxygenase-1 (HO-1) protects against hypertension in a rat model of placental ischemia; however, whether HO-1 regulation of β-ENaC contributes to the beneficial effects of HO-1 is unknown. The purpose of this study was to determine whether β-ENaC mediates cytotrophoblast migration and whether HO-1 enhances ENaC-mediated migration. We showed that placental ischemia, induced by reducing uterine perfusion suppressed, and HO-1 induction restored, β-ENaC expression in ischemic placentas. Using an in vitro model, we found that HO-1 induction, using cobalt protoporphyrin, stimulates cytotrophoblast β-ENaC expression by 1.5- and 1.8-fold (10 and 50 μM). We then showed that silencing of β-ENaC in cultured cytotrophoblasts (BeWo cells), by expression of dominant-negative constructs, reduced migration to 56 ± 13% (P < 0.05) of control. Importantly, HO-1 induction enhanced migration (43 ± 5% of control, P < 0.05), but the enhanced migratory response was entirely blocked by ENaC inhibition with amiloride (10 μM). Taken together, our results suggest that β-ENaC mediates cytotrophoblast migration and increasing β-ENaC expression by HO-1 induction enhances migration. HO-1 regulation of cytotrophoblast β-ENaC expression and migration may be a potential therapeutic target in preeclamptic patients.
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Affiliation(s)
- Junie P Warrington
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Nitta CH, Osmond DA, Herbert LM, Beasley BF, Resta TC, Walker BR, Jernigan NL. Role of ASIC1 in the development of chronic hypoxia-induced pulmonary hypertension. Am J Physiol Heart Circ Physiol 2014; 306:H41-52. [PMID: 24186095 PMCID: PMC3920158 DOI: 10.1152/ajpheart.00269.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 10/30/2013] [Indexed: 11/22/2022]
Abstract
Chronic hypoxia (CH) associated with respiratory disease results in elevated pulmonary vascular intracellular Ca(2+) concentration, which elicits enhanced vasoconstriction and promotes vascular arterial remodeling and thus has important implications in the development of pulmonary hypertension (PH). Store-operated Ca(2+) entry (SOCE) contributes to this elevated intracellular Ca(2+) concentration and has also been linked to acute hypoxic pulmonary vasoconstriction (HPV). Since our laboratory has recently demonstrated an important role for acid-sensing ion channel 1 (ASIC1) in mediating SOCE, we hypothesized that ASIC1 contributes to both HPV and the development of CH-induced PH. To test this hypothesis, we examined responses to acute hypoxia in isolated lungs and assessed the effects of CH on indexes of PH, arterial remodeling, and vasoconstrictor reactivity in wild-type (ASIC1(+/+)) and ASIC1 knockout (ASIC1(-/-)) mice. Restoration of ASIC1 expression in pulmonary arterial smooth muscle cells from ASIC1(-/-) mice rescued SOCE, confirming the requirement for ASIC1 in this response. HPV responses were blunted in lungs from ASIC1(-/-) mice. Both SOCE and receptor-mediated Ca(2+) entry, along with agonist-dependent vasoconstrictor responses, were diminished in small pulmonary arteries from control ASIC(-/-) mice compared with ASIC(+/+) mice. The effects of CH to augment receptor-mediated vasoconstrictor and SOCE responses in vessels from ASIC1(+/+) mice were not observed after CH in ASIC1(-/-) mice. In addition, ASIC1(-/-) mice exhibited diminished right ventricular systolic pressure, right ventricular hypertrophy, and arterial remodeling in response to CH compared with ASIC1(+/+) mice. Taken together, these data demonstrate an important role for ASIC1 in both HPV and the development of CH-induced PH.
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Affiliation(s)
- Carlos H Nitta
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico
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Stock C, Ludwig FT, Hanley PJ, Schwab A. Roles of ion transport in control of cell motility. Compr Physiol 2013; 3:59-119. [PMID: 23720281 DOI: 10.1002/cphy.c110056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell motility is an essential feature of life. It is essential for reproduction, propagation, embryonic development, and healing processes such as wound closure and a successful immune defense. If out of control, cell motility can become life-threatening as, for example, in metastasis or autoimmune diseases. Regardless of whether ciliary/flagellar or amoeboid movement, controlled motility always requires a concerted action of ion channels and transporters, cytoskeletal elements, and signaling cascades. Ion transport across the plasma membrane contributes to cell motility by affecting the membrane potential and voltage-sensitive ion channels, by inducing local volume changes with the help of aquaporins and by modulating cytosolic Ca(2+) and H(+) concentrations. Voltage-sensitive ion channels serve as voltage detectors in electric fields thus enabling galvanotaxis; local swelling facilitates the outgrowth of protrusions at the leading edge while local shrinkage accompanies the retraction of the cell rear; the cytosolic Ca(2+) concentration exerts its main effect on cytoskeletal dynamics via motor proteins such as myosin or dynein; and both, the intracellular and the extracellular H(+) concentration modulate cell migration and adhesion by tuning the activity of enzymes and signaling molecules in the cytosol as well as the activation state of adhesion molecules at the cell surface. In addition to the actual process of ion transport, both, channels and transporters contribute to cell migration by being part of focal adhesion complexes and/or physically interacting with components of the cytoskeleton. The present article provides an overview of how the numerous ion-transport mechanisms contribute to the various modes of cell motility.
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Affiliation(s)
- Christian Stock
- Institute of Physiology II, University of Münster, Münster, Germany.
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Hypotonic Regulation of Mouse Epithelial Sodium Channel in Xenopus laevis Oocytes. J Membr Biol 2013; 246:949-58. [DOI: 10.1007/s00232-013-9598-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/24/2013] [Indexed: 10/26/2022]
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ENaC contribution to epithelial wound healing is independent of the healing mode and of any increased expression in the channel. Cell Tissue Res 2013; 353:53-64. [DOI: 10.1007/s00441-013-1635-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/05/2013] [Indexed: 12/13/2022]
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Yang HY, Charles RP, Hummler E, Baines DL, Isseroff RR. The epithelial sodium channel mediates the directionality of galvanotaxis in human keratinocytes. J Cell Sci 2013; 126:1942-51. [PMID: 23447677 DOI: 10.1242/jcs.113225] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cellular directional migration in an electric field (galvanotaxis) is one of the mechanisms guiding cell movement in embryogenesis and in skin epidermal repair. The epithelial sodium channel (ENaC), in addition to its function of regulating sodium transport in kidney, has recently been found to modulate cell locomotory speed. Here we tested whether ENaC has an additional function of mediating the directional migration of galvanotaxis in keratinocytes. Genetic depletion of ENaC completely blocks only galvanotaxis and does not decrease migration speed. Overexpression of ENaC is sufficient to drive galvanotaxis in otherwise unresponsive cells. Pharmacologic blockade or maintenance of the open state of ENaC also decreases or increases, respectively, galvanotaxis, suggesting that the channel open state is responsible for the response. Stable lamellipodial extensions formed at the cathodal sides of wild-type cells at the start of galvanotaxis; these were absent in the ENaC knockout keratinocytes, suggesting that ENaC mediates galvanotaxis by generating stable lamellipodia that steer cell migration. We provide evidence that ENaC is required for directional migration of keratinocytes in an electric field, supporting a role for ENaC in skin wound healing.
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Affiliation(s)
- Hsin-Ya Yang
- Department of Dermatology, University of California, Davis, CA 95616, USA
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Marino G, Kotsias B. Expression of the epithelial sodium channel sensitive to amiloride (ENaC) in normal and preeclamptic human placenta. Placenta 2013; 34:197-200. [DOI: 10.1016/j.placenta.2012.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/22/2012] [Accepted: 11/11/2012] [Indexed: 10/27/2022]
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The migratory capacity of human trophoblastic BeWo cells: effects of aldosterone and the epithelial sodium channel. J Membr Biol 2013; 246:243-55. [PMID: 23354843 DOI: 10.1007/s00232-013-9526-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Accepted: 01/08/2013] [Indexed: 01/08/2023]
Abstract
Aldosterone is a key regulator of the epithelial sodium channel (ENaC) and stimulates protein methylation on the β-subunit of the ENaC. We found that aldosterone (100 nM) promotes cellular migration in a wound-healing model in trophoblastic BeWo cells. Here, we tested if the positive influence of aldosterone on wound healing is related to methylation reactions. Cell migration and proliferation were measured in BeWo cells at 6 h, when mitosis is still scarce. Cell migration covered 12.4, 25.3, 19.6 and 45.1 % of the wound when cultivated under control, aldosterone (12 h), 8Br-cAMP and aldosterone plus 8Br-cAMP, respectively. Amiloride blocked the effects of aldosterone alone or in the presence of 8Br-cAMP on wound healing. Wound healing decreased in aldosterone (plus 8Br-cAMP) coexposed with the methylation inhibitor 3-deaza-adenosine (3-DZA, 12.9 % reinvasion of the wound). There was an increase in wound healing in aldosterone-, 8Br-cAMP- and 3-DZA-treated cells in the presence of AdoMet, a methyl donor, compared to cells in the absence of AdoMet (27.3 and 12.9 % reinvasion of the wound, respectively). Cell proliferation assessed with the reagent MTT was not changed in any of these treatments, suggesting that cellular migration is the main factor for reinvasion of wound healing. Electrophysiological studies showed an increase in ENaC current in the presence of aldosterone. This effect was higher with 8Br-cAMP, and there was a decrease when 3-DZA was present. AdoMet treatment partially reversed this phenomenon. We suggest that aldosterone positively influences wound healing in BeWo cells, at least in part through methylation of the ENaC.
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Schwab A, Fabian A, Hanley PJ, Stock C. Role of ion channels and transporters in cell migration. Physiol Rev 2013; 92:1865-913. [PMID: 23073633 DOI: 10.1152/physrev.00018.2011] [Citation(s) in RCA: 315] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cell motility is central to tissue homeostasis in health and disease, and there is hardly any cell in the body that is not motile at a given point in its life cycle. Important physiological processes intimately related to the ability of the respective cells to migrate include embryogenesis, immune defense, angiogenesis, and wound healing. On the other side, migration is associated with life-threatening pathologies such as tumor metastases and atherosclerosis. Research from the last ≈ 15 years revealed that ion channels and transporters are indispensable components of the cellular migration apparatus. After presenting general principles by which transport proteins affect cell migration, we will discuss systematically the role of channels and transporters involved in cell migration.
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Jernigan NL, Herbert LM, Walker BR, Resta TC. Chronic hypoxia upregulates pulmonary arterial ASIC1: a novel mechanism of enhanced store-operated Ca2+ entry and receptor-dependent vasoconstriction. Am J Physiol Cell Physiol 2012; 302:C931-40. [PMID: 22205392 PMCID: PMC3311238 DOI: 10.1152/ajpcell.00332.2011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 12/23/2011] [Indexed: 12/19/2022]
Abstract
Acid-sensing ion channel 1 (ASIC1) is a newly characterized contributor to store-operated Ca(2+) entry (SOCE) in pulmonary vascular smooth muscle (VSM). Since SOCE is implicated in elevated basal VSM intracellular Ca(2+) concentration ([Ca(2+)](i)) and augmented vasoconstriction in chronic hypoxia (CH)-induced pulmonary hypertension, we hypothesized that ASIC1 contributes to these responses. To test this hypothesis, we examined effects of the specific pharmacologic ASIC1a inhibitor, psalmotoxin 1 (PcTX1), on vasoconstrictor and vessel wall [Ca(2+)](i) responses to UTP and KCl (depolarizing stimulus) in fura-2-loaded, pressurized small pulmonary arteries from control and CH (4 wk at 0.5 atm) Wistar rats. PcTX1 had no effect on basal vessel wall [Ca(2+)](i), but attenuated vasoconstriction and increases in vessel wall [Ca(2+)](i) to UTP in arteries from control and CH rats; normalizing responses between groups. In contrast, responses to the depolarizing stimulus, KCl, were unaffected by CH exposure or PcTX1. Upon examining potential Ca(2+) influx mechanisms, we found that PcTX1 prevented augmented SOCE following CH. Exposure to CH resulted in a significant increase in pulmonary arterial ASIC1 protein. This study supports a novel role of ASIC1 in elevated receptor-stimulated vasoconstriction following CH which is likely mediated through increased ASIC1 expression and SOCE.
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Affiliation(s)
- Nikki L Jernigan
- Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, USA.
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Abstract
The epithelial Na(+) channel (ENaC) and acid-sensitive ion channel (ASIC) branches of the ENaC/degenerin superfamily of cation channels have drawn increasing attention as potential therapeutic targets in a variety of diseases and conditions. Originally thought to be solely expressed in fluid absorptive epithelia and in neurons, it has become apparent that members of this family exhibit nearly ubiquitous expression. Therapeutic opportunities range from hypertension, due to the role of ENaC in maintaining whole body salt and water homeostasis, to anxiety disorders and pain associated with ASIC activity. As a physiologist intrigued by the fundamental mechanics of salt and water transport, it was natural that Dale Benos, to whom this series of reviews is dedicated, should have been at the forefront of research into the amiloride-sensitive sodium channel. The cloning of ENaC and subsequently the ASIC channels has revealed a far wider role for this channel family than was previously imagined. In this review, we will discuss the known and potential roles of ENaC and ASIC subunits in the wide variety of pathologies in which these channels have been implicated. Some of these, such as the role of ENaC in Liddle's syndrome are well established, others less so; however, all are related in that the fundamental defect is due to inappropriate channel activity.
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Affiliation(s)
- Yawar J Qadri
- Department of Physiology and Biophysics, University of Alabama at Birmingham, AL 35294, USA
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The plasma membrane potential and the organization of the actin cytoskeleton of epithelial cells. Int J Cell Biol 2012; 2012:121424. [PMID: 22315611 PMCID: PMC3272338 DOI: 10.1155/2012/121424] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Accepted: 10/08/2011] [Indexed: 12/22/2022] Open
Abstract
The establishment and maintenance of the polarized epithelial phenotype require a characteristic organization of the cytoskeletal components. There are many cellular effectors involved in the regulation of the cytoskeleton of epithelial cells. Recently, modifications in the plasma membrane potential (PMP) have been suggested to participate in the modulation of the cytoskeletal organization of epithelia. Here, we review evidence showing that changes in the PMP of diverse epithelial cells promote characteristic modifications in the cytoskeletal organization, with a focus on the actin cytoskeleton. The molecular paths mediating these effects may include voltage-sensitive integral membrane proteins and/or peripheral proteins sensitive to surface potentials. The voltage dependence of the cytoskeletal organization seems to have implications in several physiological processes, including epithelial wound healing and apoptosis.
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Chifflet S, Justet C, Hernández JA, Nin V, Escande C, Benech JC. Early and late calcium waves during wound healing in corneal endothelial cells. Wound Repair Regen 2011; 20:28-37. [DOI: 10.1111/j.1524-475x.2011.00749.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Accepted: 09/12/2011] [Indexed: 01/18/2023]
Affiliation(s)
- Silvia Chifflet
- Departamento de Bioquímica, Facultad de Medicina; Universidad de la República; Montevideo; Uruguay
| | - Cristian Justet
- Departamento de Bioquímica, Facultad de Medicina; Universidad de la República; Montevideo; Uruguay
| | - Julio A. Hernández
- Sección Biofísica, Facultad de Ciencias; Universidad de la República; Montevideo; Uruguay
| | - Verónica Nin
- Departamento de Histología y Embriología, Facultad de Medicina; Universidad de la República; Montevideo; Uruguay
| | - Carlos Escande
- Laboratorio de Señalización Celular y Nanobiología; IIBCE; Montevideo; Uruguay
| | - Juan C. Benech
- Laboratorio de Señalización Celular y Nanobiología; IIBCE; Montevideo; Uruguay
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Rooj AK, McNicholas CM, Bartoszewski R, Bebok Z, Benos DJ, Fuller CM. Glioma-specific cation conductance regulates migration and cell cycle progression. J Biol Chem 2011; 287:4053-65. [PMID: 22130665 DOI: 10.1074/jbc.m111.311688] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we have investigated the role of a glioma-specific cation channel assembled from subunits of the Deg/epithelial sodium channel (ENaC) superfamily, in the regulation of migration and cell cycle progression in glioma cells. Channel inhibition by psalmotoxin-1 (PcTX-1) significantly inhibited migration and proliferation of D54-MG glioma cells. Both PcTX-1 and benzamil, an amiloride analog, caused cell cycle arrest of D54-MG cells in G(0)/G(1) phases (by 30 and 40%, respectively) and reduced cell accumulation in S and G(2)/M phases after 24 h of incubation. Both PcTX-1 and benzamil up-regulated expression of cyclin-dependent kinase inhibitor proteins p21(Cip1) and p27(Kip1). Similar results were obtained in U87MG and primary glioblastoma multiforme cells maintained in primary culture and following knockdown of one of the component subunits, ASIC1. In contrast, knocking down δENaC, which is not a component of the glioma cation channel complex, had no effect on cyclin-dependent kinase inhibitor expression. Phosphorylation of ERK1/2 was also inhibited by PcTX-1, benzamil, and knockdown of ASIC1 but not δENaC in D54MG cells. Our data suggest that a specific cation conductance composed of acid-sensing ion channels and ENaC subunits regulates migration and cell cycle progression in gliomas.
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Affiliation(s)
- Arun K Rooj
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Del Mónaco SM, Marino GI, Assef YA, Damiano AE, Kotsias BA. Cell migration in BeWo cells and the role of epithelial sodium channels. J Membr Biol 2009; 232:1-13. [PMID: 19911219 DOI: 10.1007/s00232-009-9206-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 09/23/2009] [Indexed: 01/08/2023]
Abstract
Cell migration/proliferation processes associated with wound healing were measured in BeWo cells at 6 h, when mitosis is still scarce. Cells were cultured in medium with 1% fetal bovine serum to minimize proliferation. BeWo cell migration covered 20.6 +/- 7.0%, 38.0 +/- 5.4%, 16.6 +/- 4.8% and 13.7 +/- 3.6% of the wound when cultivated under control, aldosterone (100 nM, 12 h), aldosterone plus amiloride (10 muM) and amiloride treatments, respectively. When BeWo cells were treated with aldosterone, there was an increase in wound healing (P < 0.05), which was prevented by adding the ENaC blocker amiloride (P < 0.05, n = 16). Immunocytochemistry studies showed that the three ENaC subunits showed greater expression at the leading edge of the wound 3 h after injury, supporting the notion that these proteins participate in a postinjury signal. Antisense oligonucleotides directed against the alpha-ENaC subunit decreased the migratory response of the cells compared to the sense treated cells or the cells without oligonucleotides (P < 0.001, n = 16): 30.2 +/- 3.7%, 17.6 +/- 1.3%, 27.5 +/- 1.5% and 20.2 +/- 1.5% reinvasion of the wound with aldosterone, aldosterone plus antisense, aldosterone plus sense treatments and control conditions, respectively. Aldosterone and amiloride influence wound healing in BeWo cells, probably by their effects upon ENaCs, transmitting a signal to the cell cytoplasm for the release of several agents that promote cell migration.
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Affiliation(s)
- Silvana M Del Mónaco
- Laboratorio de Canales Iónicos, Instituto de Investigaciones Médicas A. Lanari, Universidad de Buenos Aires, C. de Malvinas 3150, 1427 Buenos Aires, Argentina
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Jernigan NL, Paffett ML, Walker BR, Resta TC. ASIC1 contributes to pulmonary vascular smooth muscle store-operated Ca(2+) entry. Am J Physiol Lung Cell Mol Physiol 2009; 297:L271-85. [PMID: 19482897 DOI: 10.1152/ajplung.00020.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Acid-sensing ion channels (ASIC) are voltage-insensitive, cationic channels that have recently been identified in vascular smooth muscle (VSM). It is possible that ASIC contribute to vascular reactivity via Na(+) and Ca(2+) conductance; however, their function in VSM is largely unknown. In pulmonary VSM, store-operated Ca(2+) entry (SOCE) plays a significant role in vasoregulatory mechanisms such as hypoxic pulmonary vasoconstriction and receptor-mediated arterial constriction. Therefore, we hypothesized that ASIC contribute to SOCE in pulmonary VSM. We examined SOCE resulting from depletion of intracellular Ca(2+) stores with cyclopiazonic acid in isolated small pulmonary arteries and primary cultured pulmonary arterial smooth muscle cells by measuring 1) changes in VSM [Ca(2+)](i) using fura-2 indicator dye, 2) Mn(2+) quenching of fura-2 fluorescence, and 3) store-operated Ca(2+) and Na(+) currents using conventional whole cell patch-clamp configuration in voltage-clamp mode. The role of ASIC was assessed by the use of the ASIC inhibitors, amiloride, benzamil, and psalmotoxin 1, or siRNA directed towards ASIC1, ASIC2, or ASIC3 isoforms. We found that store-operated VSM [Ca(2+)](i) responses, Mn(2+) influx, and inward cationic currents were attenuated by either pharmacological ASIC inhibition or treatment with ASIC1 siRNA. These data establish a unique role for ASIC1 in mediating SOCE in pulmonary VSM and provide new insight into mechanisms of VSM Ca(2+) entry and pulmonary vasoregulation.
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Affiliation(s)
- Nikki L Jernigan
- Dept. of Cell Biology and Physiology, Univ. of New Mexico Health Sciences Center, Albuquerque, 87131-0001, USA.
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Backlund M, Paukku K, Daviet L, De Boer RA, Valo E, Hautaniemi S, Kalkkinen N, Ehsan A, Kontula KK, Lehtonen JYA. Posttranscriptional regulation of angiotensin II type 1 receptor expression by glyceraldehyde 3-phosphate dehydrogenase. Nucleic Acids Res 2009; 37:2346-58. [PMID: 19246543 PMCID: PMC2673440 DOI: 10.1093/nar/gkp098] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Regulation of angiotensin II type 1 receptor (AT1R) has a pathophysiological role in hypertension, atherosclerosis and heart failure. We started from an observation that the 3′-untranslated region (3′-UTR) of AT1R mRNA suppressed AT1R translation. Using affinity purification for the separation of 3′-UTR-binding proteins and mass spectrometry for their identification, we describe glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as an AT1R 3′-UTR-binding protein. RNA electrophoretic mobility shift analysis with purified GAPDH further demonstrated a direct interaction with the 3′-UTR while GAPDH immunoprecipitation confirmed this interaction with endogenous AT1R mRNA. GAPDH-binding site was mapped to 1–100 of 3′-UTR. GAPDH-bound target mRNAs were identified by expression array hybridization. Analysis of secondary structures shared among GAPDH targets led to the identification of a RNA motif rich in adenines and uracils. Silencing of GAPDH increased the expression of both endogenous and transfected AT1R. Similarly, a decrease in GAPDH expression by H2O2 led to an increased level of AT1R expression. Consistent with GAPDH having a central role in H2O2-mediated AT1R regulation, both the deletion of GAPDH-binding site and GAPDH overexpression attenuated the effect of H2O2 on AT1R mRNA. Taken together, GAPDH is a translational suppressor of AT1R and mediates the effect of H2O2 on AT1R mRNA.
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Affiliation(s)
- Michael Backlund
- Biomedicum Helsinki, Department of Medicine, University of Helsinki, Helsinki, Finland
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Meguro K, Iida H, Takano H, Morita T, Sata M, Nagai R, Nakajima T. Function and role of voltage-gated sodium channel NaV1.7 expressed in aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2008; 296:H211-9. [PMID: 18978189 DOI: 10.1152/ajpheart.00960.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Voltage-gated Na(+) channel currents (I(Na)) are expressed in several types of smooth muscle cells. The purpose of this study was to evaluate the expression of I(Na), its functional role, pathophysiology in cultured human (hASMCs) and rabbit aortic smooth muscle cells (rASMCs), and its association with vascular intimal hyperplasia. In whole cell voltage clamp, I(Na) was observed at potential positive to -40 mV, was blocked by tetrodotoxin (TTX), and replacing extracellular Na(+) with N-methyl-d-glucamine in cultured hASMCs. In contrast to native aorta, cultured hASMCs strongly expressed SCN9A encoding Na(V)1.7, as determined by quantitative RT-PCR. I(Na) was abolished by the treatment with SCN9A small-interfering (si)RNA (P < 0.01). TTX and SCN9A siRNA significantly inhibited cell migration (P < 0.01, respectively) and horseradish peroxidase uptake (P < 0.01, respectively). TTX also significantly reduced the secretion of matrix metalloproteinase-2 6 and 12 h after the treatment (P < 0.01 and P < 0.05, respectively). However, neither TTX nor siRNA had any effect on cell proliferation. L-type Ca(2+) channel current was recorded, and I(Na) was not observed in freshly isolated rASMCs, whereas TTX-sensitive I(Na) was recorded in cultured rASMCs. Quantitative RT-PCR and immunostaining for Na(V)1.7 revealed the prominent expression of SCN9A in cultured rASMCs and aorta 48 h after balloon injury but not in native aorta. In conclusion, these studies show that I(Na) is expressed in cultured and diseased conditions but not in normal aorta. The Na(V)1.7 plays an important role in cell migration, endocytosis, and secretion. Na(V)1.7 is also expressed in aorta after balloon injury, suggesting a potential role for Na(V)1.7 in the progression of intimal hyperplasia.
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Affiliation(s)
- Kentaro Meguro
- Dept. of Cardiovascular Medicine, Univ. of Tokyo Graduate School of Medicine, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8655, Japan.
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Zhu H, Guo D, Li K, Yan W, Tan Y, Wang X, Treiber FA, Chao J, Snieder H, Dong Y. Prostasin: a possible candidate gene for human hypertension. Am J Hypertens 2008; 21:1028-33. [PMID: 18583984 DOI: 10.1038/ajh.2008.224] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Prostasin, a serine protease, is suggested to be a novel mechanism regulating the epithelial sodium channel (ENaC) expressed in the distal nephron. This study aimed to evaluate whether the human prostasin gene is a novel candidate gene underlying blood pressure (BP) elevation. METHODS In a sample of healthy African-American (AA) and European-American (EA) twin subjects aged 17.6 +/- 3.3 years (n = 920, 45% AAs), race-specific tagging single-nucleotide polymorphisms (tSNPs) were identified to tag all the available SNPs +/- 2 kb up- and downstream of the prostasin gene from HapMap at r2 of 0.8-1.0. Selection yielded four tSNPs in AAs and one in EAs, with one tSNP (rs12597511: C to T) present in both AAs and EAs. RESULTS For rs12597511, CT and TT genotypes exhibited higher systolic BP (SBP) than CC genotype (115.9 +/- 1.1 mm Hg vs. 113.7 +/- 0.6 mm Hg, P = 0.025 (AAs); and 110.7 +/- 0.5 mm Hg vs. 109.6 +/- 0.6 mm Hg, P = 0.115 (EAs)). CT and TT genotypes compared with CC genotype showed a significant increase in diastolic BP (DBP) in both racial groups (62.5 +/- 0.7 mm Hg vs. 60.4 +/- 0.4 mm Hg, P = 0.003 (AAs); and 58.2 +/- 0.3 mm Hg vs. 56.7 +/- 0.4 mm Hg, P = 0.007 (EAs)). Furthermore, there was an increase in radial pulse wave velocity (PWV) in subjects with CT and TT genotype as compared with those with CC genotype (6.5 +/- 0.1 vs. 6.1 +/- 0.1 m/s, P < 0.0001) (EAs); and 6.7 +/- 0.1 vs. 6.6 +/- 0.1 m/s, P = 0.354 (AAs)). Analyses combining AAs and EAs consistently demonstrated a statistical significance of rs12597511 on all the phenotypes including SBP/DBP and PWV. CONCLUSION Genetic variation of the prostasin gene may be implicated in the development of hypertension in youths..
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Paukku K, Kalkkinen N, Silvennoinen O, Kontula KK, Lehtonen JYA. p100 increases AT1R expression through interaction with AT1R 3'-UTR. Nucleic Acids Res 2008; 36:4474-87. [PMID: 18603592 PMCID: PMC2490763 DOI: 10.1093/nar/gkn411] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
p100 protein (SND1, Tudor-SN) is a multifunctional protein that functions as a co-activator for several transcription factors, has a role in mRNA processing and participates in RNAi-induced silencing complex (RISC) with yet unknown function. In this study we identified a novel function for p100 as a regulator of angiotensin II type 1 receptor (AT1R) expression. The binding of p100 to AT1R 3′-untranslated region (3′-UTR) via staphylococcal nuclease-like (SN-like) domains increased receptor expression by decreasing the rate of mRNA decay and enhancing its translation. Overexpression of p100 increased AT1R expression, whereas decrease in p100 binding to 3′-UTR either by p100 silencing or by the deletion of p100 binding site downregulated receptor expression. The effect of p100 through AT1R 3′-UTR was independent of Argonaute2 (Ago2), a known p100 partner, and was thus RISC-independent. Nucleotides 118 to 120 of the AT1R 3′-UTR were found to be critical for the binding of p100 to 3′-UTR. In summary, p100 is a multifunctional regulator of gene expression that regulates transcription, mRNA maturation, and as described in this article, also mRNA stability and translation.
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Affiliation(s)
- Kirsi Paukku
- Research Program for Molecular Medicine, Biomedicum Helsinki, University of Helsinki, Finland.
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Fuller CM, Benos DJ. Putting the brakes on vascular smooth muscle cell migration. Am J Physiol Heart Circ Physiol 2008; 294:H1987-8. [DOI: 10.1152/ajpheart.00249.2008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Drummond HA, Grifoni SC, Jernigan NL. A new trick for an old dogma: ENaC proteins as mechanotransducers in vascular smooth muscle. Physiology (Bethesda) 2008; 23:23-31. [PMID: 18268362 DOI: 10.1152/physiol.00034.2007] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Myogenic constriction is a vasoconstriction of blood vessels to increases in perfusion pressure. In renal preglomerular vasculature, it is an established mechanism of renal blood flow autoregulation. Recently, myogenic constriction has been identified as an important protective mechanism, preventing the transmission of systemic pressure to the fragile glomerular vasculature. Although the signal transduction pathways mediating vasoconstriction are well known, how the increases in pressure trigger vasoconstriction is unclear. The response is initiated by pressure-induced stretch of the vessel wall and thus is dependent on mechanical signaling. The identity of the sensor detecting VSMC stretch is unknown. Previous studies have considered the role of extracellular matrix-integrin interactions, ion conduction units (channels and/or transporters), and the cytoskeleton as pressure detectors. Whether, and how, these structures fit together in VSMCs is poorly understood. However, a model of mechanotransduction in the nematode Caenorhadbditis elegans (C. elegans) has been established that ties together extracellular matrix, ion channels, and cytoskeletal proteins into a large mechanosensing complex. In the C. elegans mechanotransducer model, a family of evolutionarily conserved proteins, referred to as the DEG/ENaC/ASIC family, form the ion-conducting pore of the mechanotransducer. Members of this protein family are expressed in VSMC where they may participate in pressure detection. This review will address how the C. elegans mechanotransducer model can be used to model pressure detection in mammalian VSMCs and provide a new perspective to pressure detection in VSMCs.
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Affiliation(s)
- Heather A Drummond
- Department of Physiology and Biophysics, and Center for Excellence in Cardio-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi, USA.
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Gannon KP, VanLandingham LG, Jernigan NL, Grifoni SC, Hamilton G, Drummond HA. Impaired pressure-induced constriction in mouse middle cerebral arteries of ASIC2 knockout mice. Am J Physiol Heart Circ Physiol 2008; 294:H1793-803. [DOI: 10.1152/ajpheart.01380.2007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies from our laboratory demonstrated the importance of mechanosensitive epithelial Na+channel (ENaC) proteins in pressure-induced constriction in renal and cerebral arteries. ENaC proteins are closely related to acid-sensing ion channel 2 (ASIC2), a protein known to be required for normal mechanotransduction in certain sensory neurons. However, the role of the ASIC2 protein in pressure-induced constriction has never been addressed. The goal of the current study was to investigate the role of ASIC2 proteins in pressure-induced, or myogenic, constriction in the mouse middle cerebral arteries (MCAs) from ASIC2 wild-type (+/+), heterozygous (+/−), and null (−/−) mice. Constrictor responses to KCl (20–80 mM) and phenylephrine (10−7–10−4M) were not different among groups. However, vasoconstrictor responses to increases in intraluminal pressure (15–90 mmHg) were impaired in MCAs from ASIC2−/−and+/−mice. At 60 and 90 mmHg, MCAs from ASIC2+/+mice generated 13.7 ± 2.1% and 15.8 ± 2.0% tone and ASIC2−/−mice generated 7.4 ± 2.8% and 12.5 ± 2.4% tone, respectively. Surprisingly, MCAs from ASIC2+/−mice generated 1.2 ± 2.2% and 3.9 ± 1.8% tone at 60 and 90 mmHg. The reason underlying the total loss of myogenic tone in the ASIC2+/−is not clear, although the loss of mechanosensitive β- and γ-ENaC proteins may be a contributing factor. These results demonstrate that normal ASIC2 expression is required for normal pressure-induced constriction in the MCA. Furthermore, ASIC2 may be involved in establishing the basal level of myogenic tone.
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