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Gao Y, Cao F, Tian X, Zhang Q, Xu C, Ji B, Zhang YA, Du L, Han J, Li L, Zhou S, Gong Y, Ying B, Gao-Smith F, Jin S. Inhibition the ubiquitination of ENaC and Na,K-ATPase with erythropoietin promotes alveolar fluid clearance in sepsis-induced acute respiratory distress syndrome. Biomed Pharmacother 2024; 174:116447. [PMID: 38518606 DOI: 10.1016/j.biopha.2024.116447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/08/2024] [Accepted: 03/15/2024] [Indexed: 03/24/2024] Open
Abstract
Sepsis-induced acute respiratory distress syndrome (ARDS) causes significant fatalities worldwide and lacks pharmacological intervention. Alveolar fluid clearance (AFC) plays a pivotal role in the remission of ARDS and is markedly impaired in the pathogenesis of ARDS. Here, we demonstrated that erythropoietin could effectively ameliorate lung injury manifestations and lethality, restore lung function and promote AFC in a rat model of lipopolysaccharide (LPS)-induced ARDS. Moreover, it was proven that EPO-induced restoration of AFC occurs through triggering the total protein expression of ENaC and Na,K-ATPase channels, enhancing their protein abundance in the membrane, and suppressing their ubiquitination for degeneration. Mechanistically, the data indicated the possible involvement of EPOR/JAK2/STAT3/SGK1/Nedd4-2 signaling in this process, and the pharmacological inhibition of the pathway markedly eliminated the stimulating effects of EPO on ENaC and Na,K-ATPase, and subsequently reversed the augmentation of AFC by EPO. Consistently, in vitro studies of alveolar epithelial cells paralleled with that EPO upregulated the expression of ENaC and Na,K-ATPase, and patch-clamp studies further demonstrated that EPO substantially strengthened sodium ion currents. Collectively, EPO could effectively promote AFC by improving ENaC and Na,K-ATPase protein expression and abundance in the membrane, dependent on inhibition of ENaC and Na,K-ATPase ubiquitination, and resulting in diminishing LPS-associated lung injuries.
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Affiliation(s)
- Ye Gao
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Fei Cao
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China; Department of Anesthesiology, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Xinyi Tian
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Qianping Zhang
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Congcong Xu
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Bowen Ji
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Ye-An Zhang
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Linan Du
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Jun Han
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Li Li
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Siyu Zhou
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Yuqiang Gong
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Binyu Ying
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China
| | - Fang Gao-Smith
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China; Centre for Translational Inflammation Research, Institute of Inflammation and Aging, University of Birmingham, Birmingham, United Kingdom.
| | - Shengwei Jin
- Department of Anaesthesia, Pain and Critical Care, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China; Key Laboratory of Pediatric Anesthesiology, Ministry of Education, Wenzhou Medical University, Zhejiang, China; Laboratory of Anesthesiology of Zhejiang Province, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Zhejiang, China.
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Ostrosky-Frid M, Chávez-Canales M, Zhang J, Andrukhova O, Argaiz ER, Lerdo-de-Tejada F, Murillo-de-Ozores A, Sanchez-Navarro A, Rojas-Vega L, Bobadilla NA, Vazquez N, Castañeda-Bueno M, Alessi DR, Gamba G. Role of KLHL3 and dietary K + in regulating KS-WNK1 expression. Am J Physiol Renal Physiol 2021; 320:F734-F747. [PMID: 33682442 PMCID: PMC8174809 DOI: 10.1152/ajprenal.00575.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 03/03/2021] [Accepted: 03/03/2021] [Indexed: 02/08/2023] Open
Abstract
The physiological role of the shorter isoform of with no lysine kinase (WNK)1 that is exclusively expressed in the kidney (KS-WNK1), with particular abundance in the distal convoluted tubule, remains elusive. KS-WNK1, despite lacking the kinase domain, is nevertheless capable of stimulating the NaCl cotransporter, apparently through activation of WNK4. It has recently been shown that a less severe form of familial hyperkalemic hypertension featuring only hyperkalemia is caused by missense mutations in the WNK1 acidic domain that preferentially affect cullin 3 (CUL3)-Kelch-like protein 3 (KLHL3) E3-induced degradation of KS-WNK1 rather than that of full-length WNK1. Here, we show that full-length WNK1 is indeed less impacted by the CUL3-KLHL3 E3 ligase complex compared with KS-WNK1. We demonstrated that the unique 30-amino acid NH2-terminal fragment of KS-WNK1 is essential for its activating effect on the NaCl cotransporter and recognition by KLHL3. We identified specific amino acid residues in this region critical for the functional effect of KS-WNK1 and KLHL3 sensitivity. To further explore this, we generated KLHL3-R528H knockin mice that mimic human mutations causing familial hyperkalemic hypertension. These mice revealed that the KLHL3 mutation specifically increased expression of KS-WNK1 in the kidney. We also observed that in wild-type mice, the expression of KS-WNK1 was only detectable after exposure to a low-K+ diet. These findings provide new insights into the regulation and function of KS-WNK1 by the CUL3-KLHL3 complex in the distal convoluted tubule and indicate that this pathway is regulated by dietary K+ levels.NEW & NOTEWORTHY In this work, we demonstrated that the kidney-specific isoform of with no lysine kinase 1 (KS-WNK1) in the kidney is modulated by dietary K+ and activity of the ubiquitin ligase protein Kelch-like protein 3. We analyzed the role of different amino acid residues of KS-WNK1 in its activity against the NaCl cotransporter and sensitivity to Kelch-like protein 3.
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Affiliation(s)
- Mauricio Ostrosky-Frid
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
- PECEM (MD/PhD), Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Chávez-Canales
- Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter, United Kingdom
| | - Olena Andrukhova
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Eduardo R Argaiz
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Fernando Lerdo-de-Tejada
- Unidad de Investigación UNAM-INC, Instituto Nacional de Cardiología Ignacio Chávez and Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Adrian Murillo-de-Ozores
- Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Andrea Sanchez-Navarro
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Lorena Rojas-Vega
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Norma A Bobadilla
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Norma Vazquez
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Dario R Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
- PECEM (MD/PhD), Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Ware AW, Rasulov SR, Cheung TT, Lott JS, McDonald FJ. Membrane trafficking pathways regulating the epithelial Na + channel. Am J Physiol Renal Physiol 2019; 318:F1-F13. [PMID: 31657249 DOI: 10.1152/ajprenal.00277.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Renal Na+ reabsorption, facilitated by the epithelial Na+ channel (ENaC), is subject to multiple forms of control to ensure optimal body blood volume and pressure through altering both the ENaC population and activity at the cell surface. Here, the focus is on regulating the number of ENaCs present in the apical membrane domain through pathways of ENaC synthesis and targeting to the apical membrane as well as ENaC removal, recycling, and degradation. Finally, the mechanisms by which ENaC trafficking pathways are regulated are summarized.
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Affiliation(s)
- Adam W Ware
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Sahib R Rasulov
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Tanya T Cheung
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - J Shaun Lott
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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Liu Y, Jiang BJ, Zhao RZ, Ji HL. Epithelial Sodium Channels in Pulmonary Epithelial Progenitor and Stem Cells. Int J Biol Sci 2016; 12:1150-4. [PMID: 27570489 PMCID: PMC4997059 DOI: 10.7150/ijbs.15747] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/11/2016] [Indexed: 11/05/2022] Open
Abstract
Regeneration of the epithelium of mammalian lungs is essential for restoring normal function following injury, and various cells and mechanisms contribute to this regeneration and repair. Club cells, bronchioalveolar stem cells (BASCs), and alveolar type II epithelial cells (ATII) are dominant stem/progenitor cells for maintaining epithelial turnover and repair. Epithelial Na(+) channels (ENaC), a critical pathway for transapical salt and fluid transport, are expressed in lung epithelial progenitors, including club and ATII cells. Since ENaC activity and expression are development- and differentiation-dependent, apically located ENaC activity has therefore been used as a functional biomarker of lung injury repair. ENaC activity may be involved in the migration and differentiation of local and circulating stem/progenitor cells with diverse functions, eventually benefiting stem cells spreading to re-epithelialize injured lungs. This review summarizes the potential roles of ENaC expressed in native progenitor and stem cells in the development and regeneration of the respiratory epithelium.
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Affiliation(s)
- Yang Liu
- Institute of Lung and Molecular Therapy, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Bi-Jie Jiang
- School of Public Health, Xinxiang Medical University, Xinxiang, Henan 453003, China
| | - Run-Zhen Zhao
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708, USA
- Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas 75708, USA
| | - Hong-Long Ji
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708, USA
- Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas 75708, USA
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Lou Y, Zhang F, Luo Y, Wang L, Huang S, Jin F. Serum and Glucocorticoid Regulated Kinase 1 in Sodium Homeostasis. Int J Mol Sci 2016; 17:ijms17081307. [PMID: 27517916 PMCID: PMC5000704 DOI: 10.3390/ijms17081307] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
The ubiquitously expressed serum and glucocorticoid regulated kinase 1 (SGK1) is tightly regulated by osmotic and hormonal signals, including glucocorticoids and mineralocorticoids. Recently, SGK1 has been implicated as a signal hub for the regulation of sodium transport. SGK1 modulates the activities of multiple ion channels and carriers, such as epithelial sodium channel (ENaC), voltage-gated sodium channel (Nav1.5), sodium hydrogen exchangers 1 and 3 (NHE1 and NHE3), sodium-chloride symporter (NCC), and sodium-potassium-chloride cotransporter 2 (NKCC2); as well as the sodium-potassium adenosine triphosphatase (Na+/K+-ATPase) and type A natriuretic peptide receptor (NPR-A). Accordingly, SGK1 is implicated in the physiology and pathophysiology of Na+ homeostasis. Here, we focus particularly on recent findings of SGK1’s involvement in Na+ transport in renal sodium reabsorption, hormone-stimulated salt appetite and fluid balance and discuss the abnormal SGK1-mediated Na+ reabsorption in hypertension, heart disease, edema with diabetes, and embryo implantation failure.
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Affiliation(s)
- Yiyun Lou
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Department of Gynaecology, Hangzhou Hospital of Traditional Chinese Medicine, Hangzhou 310007, Zhejiang, China.
| | - Fan Zhang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Yuqin Luo
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Liya Wang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Shisi Huang
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
| | - Fan Jin
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou 310006, Zhejiang, China.
- Key Laboratory of Reproductive Genetics, National Ministry of Education (Zhejiang University), Women's Reproductive Healthy Laboratory of Zhejiang Province, Hangzhou 310058, Zhejiang, China.
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Kielgast F, Schmidt H, Braubach P, Winkelmann VE, Thompson KE, Frick M, Dietl P, Wittekindt OH. Glucocorticoids Regulate Tight Junction Permeability of Lung Epithelia by Modulating Claudin 8. Am J Respir Cell Mol Biol 2016; 54:707-17. [DOI: 10.1165/rcmb.2015-0071oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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The neuronal-specific SGK1.1 (SGK1_v2) kinase as a transcriptional modulator of BAG4, Brox, and PPP1CB genes expression. Int J Mol Sci 2015; 16:7462-77. [PMID: 25849655 PMCID: PMC4425028 DOI: 10.3390/ijms16047462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/25/2015] [Accepted: 03/30/2015] [Indexed: 01/12/2023] Open
Abstract
The Serum- and Glucocorticoid-induced Kinase 1, SGK1, exhibits a broad range of cellular functions that include regulation of the number of ion channels in plasma membrane and modulation of signaling pathways of cell survival. This diversity of functions is made possible by various regulatory processes acting upon the SGK1 gene, giving rise to various isoforms: SGK1_v1–5, each with distinct properties and distinct aminotermini that serve to target proteins to different subcellular compartments. Among cellular effects of SGK1 expression is to indirectly modulate gene transcription by phosphorylating transcriptional factors of the FOXO family. Here we examined if SGK1.1 (SGK1_v2; NM_001143676), which associates primarily to the plasma membrane, is also able to regulate gene expression. Using a differential gene expression approach we identified six genes upregulated by SGK1.1 in HeLa cells. Further analysis of transcript and protein levels validated two genes: BCL2-associated athanogene 4 (BAG-4) and Brox. The results indicate that SGK1.1 regulates gene transcription upon a different set of genes some of which participate in cell survival pathways (BAG-4) and others in intracellular vesicular traffic (Brox).
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Janér C, Pitkänen OM, Süvari L, Turpeinen U, Palojärvi A, Andersson S, Helve O. Duration of gestation and mode of delivery affect the genes of transepithelial sodium transport in pulmonary adaptation. Neonatology 2015; 107:27-33. [PMID: 25301528 DOI: 10.1159/000363729] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/19/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND Respiratory distress due to inadequate lung liquid clearance is a significant problem in infants delivered late preterm or early term, especially by elective cesarean delivery (CD). Lung liquid clearance depends on epithelial ion transport and in animals is induced by glucocorticoids. OBJECTIVES In newborn late preterm and term infants to study airway epithelial gene expressions of epithelial sodium channel (ENaC), and the serum and glucocorticoid-inducible kinase 1 (SGK1), and their association with cortisol, mode of delivery, and gestational age (GA). METHODS Infants were delivered at 35(0/7)-41(6/7) weeks. Cortisol in umbilical cord plasma was analyzed with liquid chromatography-tandem mass spectrometry. ENaC and SGK1 mRNAs in airway epithelial cells obtained within 3 h and at 1 day postnatally were quantified with real-time PCR. RESULTS ENaC and SGK1 mRNAs were significantly lower in late preterm and early term infants than in those ≥ 39(0/7) weeks. Significant correlations existed between both ENaC and SGK1 and cord cortisol and GA. In term infants, SGK1 mRNA at 1.5 h was higher after vaginal delivery than elective CD. CONCLUSIONS In late preterm and early term infants, low expression of ENaC and SGK1 may parallel insufficient lung liquid clearance predisposing to respiratory distress. Lower SGK1 expression after term CD could translate into insufficient sodium and lung liquid absorption. The findings demonstrate a central role for cortisol in regulation of ENaC and potentially perinatal sodium and lung liquid clearance.
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Affiliation(s)
- Cecilia Janér
- Children's Hospital, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland
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Land SC, Scott CL, Walker D. mTOR signalling, embryogenesis and the control of lung development. Semin Cell Dev Biol 2014; 36:68-78. [PMID: 25289569 DOI: 10.1016/j.semcdb.2014.09.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 09/07/2014] [Accepted: 09/11/2014] [Indexed: 12/15/2022]
Abstract
The existence of a nutrient sensitive "autocatakinetic" regulator of embryonic tissue growth has been hypothesised since the early 20th century, beginning with pioneering work on the determinants of foetal size by the Australian physiologist, Thorburn Brailsford-Robertson. We now know that the mammalian target of rapamycin complexes (mTORC1 and 2) perform this essential function in all eukaryotic tissues by balancing nutrient and energy supply during the first stages of embryonic cleavage, the formation of embryonic stem cell layers and niches, the highly specified programmes of tissue growth during organogenesis and, at birth, paving the way for the first few breaths of life. This review provides a synopsis of the role of the mTOR complexes in each of these events, culminating in an analysis of lung branching morphogenesis as a way of demonstrating the central role mTOR in defining organ structural complexity. We conclude that the mTOR complexes satisfy the key requirements of a nutrient sensitive growth controller and can therefore be considered as Brailsford-Robertson's autocatakinetic centre that drives tissue growth programmes during foetal development.
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Affiliation(s)
- Stephen C Land
- Division of Cardiovascular and Diabetes Medicine, Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK.
| | - Claire L Scott
- Prostrakan Pharmaceuticals, Galabank Business Park, Galashiels TD1 1PR, UK
| | - David Walker
- School of Psychology & Neuroscience, Westburn Lane, St Andrews KY16 9JP, UK
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The phosphorylation of endogenous Nedd4-2 In Na(+)-absorbing human airway epithelial cells. Eur J Pharmacol 2014; 732:32-42. [PMID: 24657276 PMCID: PMC4022840 DOI: 10.1016/j.ejphar.2014.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/03/2014] [Accepted: 03/10/2014] [Indexed: 11/24/2022]
Abstract
Neural precursor cell expressed, developmentally down-regulated protein 4-2 (Nedd4-2) mediates the internalisation / degradation of epithelial Na+ channel subunits (α-, β- and γ-ENaC). Serum / glucocorticoid inducible kinase 1 (SGK1) and protein kinase A (PKA) both appear to inhibit this process by phosphorylating Nedd4-2-Ser221, -Ser327 and -Thr246. This Nedd4-2 inactivation process is thought to be central to the hormonal control of Na+ absorption. The present study of H441 human airway epithelial cells therefore explores the effects of SGK1 and / or PKA upon the phosphorylation / abundance of endogenous Nedd4-2; the surface expression of ENaC subunits, and electrogenic Na+ transport. Effects on Nedd4-2 phosphorylation/abundance and the surface expression of ENaC were monitored by western analysis, whilst Na+ absorption was quantified electrometrically. Acutely (20 min) activating PKA in glucocorticoid-deprived (24 h) cells increased the abundance of Ser221-phosphorylated, Ser327-phosphorylated and total Nedd4-2 without altering the abundance of Thr246-phosphorylated Nedd4-2. Activating PKA under these conditions did not cause a co-ordinated increase in the surface abundance of α-, β- and γ-ENaC and had only a very small effect upon electrogenic Na+ absorption. Activating PKA (20 min) in glucocorticoid-treated (0.2 µM dexamethasone, 24 h) cells, on the other hand, increased the abundance of Ser221-, Ser327- and Thr246-phosphorylated and total Nedd4-2; increased the surface abundance of α-, β- and γ-ENaC and evoked a clear stimulation of Na+ transport. Chronic glucocorticoid stimulation therefore appears to allow cAMP-dependent control of Na+ absorption by facilitating the effects of PKA upon the Nedd4-2 and ENaC subunits.
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Kim BG, Kim JY, Kim M, Kim CH, Choi JY, Kim SH. Gene regulation by glucocorticoid in ENaC-mediated Na⁺ transport by middle ear epithelial cells. Laryngoscope 2013; 124:E27-33. [PMID: 24114932 DOI: 10.1002/lary.24397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 08/02/2013] [Accepted: 08/19/2013] [Indexed: 11/11/2022]
Abstract
OBJECTIVES/HYPOTHESIS The epithelial sodium channel (ENaC) is a Na(+) transport channel located in the apical membrane of the human middle ear epithelium. Although ENaC-mediated sodium transport has been reported to be upregulated by dexamethasone in human middle ear epithelium, there has been no study of the downstream pathways for increased ENaC expression mediated by glucocorticoids in this tissue. We investigated the effect of dexamethasone on the expression of ENaC and glucocorticoid regulatory genes for ENaC expression in human middle ear epithelial cells (HMEECs). STUDY DESIGN In vitro investigation. METHODS Real-time RT-PCR and Western blot analysis were used to determine the expression level of ENaC and its regulatory genes in HMEECs. RESULTS The transcript and protein expression of the α-, β-, and γ-ENaC subunits were all upregulated by dexamethasone (100 nM) in HMEECs. Dexamethasone treatment also increased the transcript expression of serum/glucocorticoid-regulated kinase1 (SGK1) and neural precursor cell-expressed developmentally downregulated (Nedd) 4-2, and decreased the transcript expression of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). ENaC transcript expression was not changed after mifepristone (a glucocorticoid antagonist, 100 nM) + dexamethasone treatment when compared to the control, but increased after spironolactone (a mineralocorticoid antagonist, 100 nM) + dexamethasone treatment. CONCLUSIONS These findings indicate that dexamethasone increases the transcript and protein expression of the α-, β-, and γ-ENaC subunits via the GR-SGK1-Nedd4-2 pathway and provides insight into the molecular mechanism of the increased sodium transport mediated by ENaC with steroid treatment in HMEECs. LEVEL OF EVIDENCE N/A.
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Affiliation(s)
- Bo G Kim
- Department of Otorhinolaryngology, Yonsei University, College of Medicine, Seoul
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Lang F, Voelkl J. Therapeutic potential of serum and glucocorticoid inducible kinase inhibition. Expert Opin Investig Drugs 2013; 22:701-14. [PMID: 23506284 DOI: 10.1517/13543784.2013.778971] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Expression of serum-and-glucocorticoid-inducible kinase-1 (SGK1) is low in most cells, but dramatically increases under certain pathophysiological conditions, such as glucocorticoid or mineralocorticoid excess, inflammation with TGFβ release, hyperglycemia, cell shrinkage and ischemia. SGK1 is activated by insulin and growth factors via phosphatidylinositide-3-kinase, 3-phosphoinositide-dependent kinase and mammalian target of rapamycin. SGK1 sensitive functions include activation of ion channels (including epithelial Na(+) channel ENaC, voltage gated Na(+) channel SCN5A transient receptor potential channels TRPV4 - 6, Ca(2+) release activated Ca(2+) channel Orai1/STIM1, renal outer medullary K(+) channel ROMK, voltage gated K(+) channels KCNE1/KCNQ1, kainate receptor GluR6, cystic fibrosis transmembrane regulator CFTR), carriers (including Na(+),Cl(-) symport NCC, Na(+),K(+),2Cl(-) symport NKCC, Na(+)/H(+) exchangers NHE1 and NHE3, Na(+), glucose symport SGLT1, several amino acid transporters), and Na(+)/K(+)-ATPase. SGK1 regulates several enzymes (e.g., glycogen synthase kinase-3, ubiquitin-ligase Nedd4-2) and transcription factors (e.g., forkhead transcription factor 3a, β-catenin, nuclear factor kappa B). AREAS COVERED The phenotype of SGK1 knockout mice is mild and SGK1 is apparently dispensible for basic functions. Excessive SGK1 expression and activity, however, contributes to the pathophysiology of several disorders, including hypertension, obesity, diabetes, thrombosis, stroke, fibrosing disease, infertility and tumor growth. A SGK1 gene variant (prevalence ∼ 3 - 5% in Caucasians and ∼ 10% in Africans) is associated with hypertension, stroke, obesity and type 2 diabetes. SGK1 inhibitors have been developed and shown to reduce blood pressure of hyperinsulinemic mice and to counteract tumor cell survival. EXPERT OPINION Targeting SGK1 may be a therapeutic option in several clinical conditions, including metabolic syndrome and tumor growth.
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Affiliation(s)
- Florian Lang
- University of Tuebingen, Department of Physiology, Tuebingen, Germany.
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Lang F, Shumilina E. Regulation of ion channels by the serum- and glucocorticoid-inducible kinase SGK1. FASEB J 2012; 27:3-12. [PMID: 23012321 DOI: 10.1096/fj.12-218230] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The ubiquitously expressed serum- and glucocorticoid-inducible kinase-1 (SGK1) is genomically regulated by cell stress (including cell shrinkage) and several hormones (including gluco- and mineralocorticoids). SGK1 is activated by insulin and growth factors through PI3K and 3-phosphoinositide-dependent kinase PDK1. SGK1 activates a wide variety of ion channels (e.g., ENaC, SCN5A, TRPV4-6, ROMK, Kv1.3, Kv1.5, Kv4.3, KCNE1/KCNQ1, KCNQ4, ASIC1, GluR6, ClCKa/barttin, ClC2, CFTR, and Orai/STIM), which participate in the regulation of transport, hormone release, neuroexcitability, inflammation, cell proliferation, and apoptosis. SGK1-sensitive ion channels participate in the regulation of renal Na(+) retention and K(+) elimination, blood pressure, gastric acid secretion, cardiac action potential, hemostasis, and neuroexcitability. A common (∼3-5% prevalence in Caucasians and ∼10% in Africans) SGK1 gene variant is associated with increased blood pressure and body weight as well as increased prevalence of type II diabetes and stroke. SGK1 further contributes to the pathophysiology of allergy, peptic ulcer, fibrosing disease, ischemia, tumor growth, and neurodegeneration. The effect of SGK1 on channel activity is modest, and the channels do not require SGK1 for basic function. SGK1-dependent ion channel regulation may thus become pathophysiologically relevant primarily after excessive (pathological) expression. Therefore, SGK1 may be considered an attractive therapeutic target despite its broad range of functions.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tuebingen, Gmelinstrasse 5, 72076 Tuebingen, Germany.
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