1
|
Kang MJ, Ioannou S, Lougheide Q, Dittmar M, Hsu Y, Pastor-Soler NM. The study of intercalated cells using ex vivo techniques: primary cell culture, cell lines, kidney slices, and organoids. Am J Physiol Cell Physiol 2024; 326:C229-C251. [PMID: 37899748 DOI: 10.1152/ajpcell.00479.2022] [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: 10/27/2022] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 10/31/2023]
Abstract
This review summarizes methods to study kidney intercalated cell (IC) function ex vivo. While important for acid-base homeostasis, IC dysfunction is often not recognized clinically until it becomes severe. The advantage of using ex vivo techniques is that they allow for the differential evaluation of IC function in controlled environments. Although in vitro kidney tubular perfusion is a classical ex vivo technique to study IC, here we concentrate on primary cell cultures, immortalized cell lines, and ex vivo kidney slices. Ex vivo techniques are useful in evaluating IC signaling pathways that allow rapid responses to extracellular changes in pH, CO2, and bicarbonate (HCO3-). However, these methods for IC work can also be challenging, as cell lines that recapitulate IC do not proliferate easily in culture. Moreover, a "pure" IC population in culture does not necessarily replicate its collecting duct (CD) environment, where ICs are surrounded by the more abundant principal cells (PCs). It is reassuring that many findings obtained in ex vivo IC systems signaling have been largely confirmed in vivo. Some of these newly identified signaling pathways reveal that ICs are important for regulating NaCl reabsorption, thus suggesting new frontiers to target antihypertensive treatments. Moreover, recent single-cell characterization studies of kidney epithelial cells revealed a dual developmental origin of IC, as well as the presence of novel CD cell types with certain IC characteristics. These exciting findings present new opportunities for the study of IC ex vivo and will likely rediscover the importance of available tools in this field.NEW & NOTEWORTHY The study of kidney intercalated cells has been limited by current cell culture and kidney tissue isolation techniques. This review is to be used as a reference to select ex vivo techniques to study intercalated cells. We focused on the use of cell lines and kidney slices as potential useful models to study membrane transport proteins. We also review how novel collecting duct organoids may help better elucidate the role of these intriguing cells.
Collapse
Affiliation(s)
- Min Ju Kang
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of USC, Los Angeles, California, United States
| | - Silvia Ioannou
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of USC, Los Angeles, California, United States
| | - Quinn Lougheide
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of USC, Los Angeles, California, United States
| | - Michael Dittmar
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of USC, Los Angeles, California, United States
| | - Young Hsu
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of USC, Los Angeles, California, United States
| | - Nuria M Pastor-Soler
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of USC, Los Angeles, California, United States
| |
Collapse
|
2
|
Shi M, McCracken KW, Patel AB, Zhang W, Ester L, Valerius MT, Bonventre JV. Human ureteric bud organoids recapitulate branching morphogenesis and differentiate into functional collecting duct cell types. Nat Biotechnol 2023; 41:252-261. [PMID: 36038632 PMCID: PMC9957856 DOI: 10.1038/s41587-022-01429-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 07/13/2022] [Indexed: 12/29/2022]
Abstract
Directed differentiation of human pluripotent stem cells (hPSCs) into functional ureteric and collecting duct (CD) epithelia is essential to kidney regenerative medicine. Here we describe highly efficient, serum-free differentiation of hPSCs into ureteric bud (UB) organoids and functional CD cells. The hPSCs are first induced into pronephric progenitor cells at 90% efficiency and then aggregated into spheres with a molecular signature similar to the nephric duct. In a three-dimensional matrix, the spheres form UB organoids that exhibit branching morphogenesis similar to the fetal UB and correct distal tip localization of RET expression. Organoid-derived cells incorporate into the UB tips of the progenitor niche in chimeric fetal kidney explant culture. At later stages, the UB organoids differentiate into CD organoids, which contain >95% CD cell types as estimated by single-cell RNA sequencing. The CD epithelia demonstrate renal electrophysiologic functions, with ENaC-mediated vectorial sodium transport by principal cells and V-type ATPase proton pump activity by FOXI1-induced intercalated cells.
Collapse
Affiliation(s)
- Min Shi
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Division of Nephrology, Kidney Research Institute, West China Hospital of Sichuan University, Chengdu, China
| | - Kyle W McCracken
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. .,Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA. .,Division of Nephrology, Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, USA.
| | - Ankit B Patel
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Weitao Zhang
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Lioba Ester
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Department II of Internal Medicine, University of Cologne, Faculty of Medicine, and University Hospital Cologne, Cologne, Germany
| | - M Todd Valerius
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Harvard Stem Cell Institute, Cambridge and Boston, Boston, MA, USA
| | - Joseph V Bonventre
- Division of Renal Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. .,Harvard Stem Cell Institute, Cambridge and Boston, Boston, MA, USA. .,Division of Engineering in Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
3
|
Papadimitriou A, Romagnani P, Angelotti ML, Noor M, Corcoran J, Raby K, Wilson PD, Li J, Fraser D, Piedagnel R, Hendry BM, Xu Q. Collecting duct cells show differential retinoic acid responses to acute versus chronic kidney injury stimuli. Sci Rep 2020; 10:16683. [PMID: 33028882 PMCID: PMC7542174 DOI: 10.1038/s41598-020-73099-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/07/2020] [Indexed: 01/14/2023] Open
Abstract
Retinoic acid (RA) activates RA receptors (RAR), resulting in RA response element (RARE)-dependent gene expression in renal collecting duct (CD). Emerging evidence supports a protective role for this activity in acute kidney injury (AKI) and chronic kidney disease (CKD). Herein, we examined this activity in RARE-LacZ transgenic mice and by RARE-Luciferase reporter assays in CD cells, and investigated how this activity responds to neurotransmitters and mediators of kidney injury. In RARE-LacZ mice, Adriamycin-induced heavy albuminuria was associated with reduced RA/RAR activity in CD cells. In cultured CD cells, RA/RAR activity was repressed by acetylcholine, albumin, aldosterone, angiotensin II, high glucose, cisplatin and lipopolysaccharide, but was induced by aristolochic acid I, calcitonin gene-related peptide, endothelin-1, gentamicin, norepinephrine and vasopressin. Compared with age-matched normal human CD cells, CD-derived renal cystic epithelial cells from patients with autosomal recessive polycystic kidney disease (ARPKD) had significantly lower RA/RAR activity. Synthetic RAR agonist RA-568 was more potent than RA in rescuing RA/RAR activity repressed by albumin, high glucose, angiotensin II, aldosterone, cisplatin and lipopolysaccharide. Hence, RA/RAR in CD cells is a convergence point of regulation by neurotransmitters and mediators of kidney injury, and may be a novel therapeutic target.
Collapse
Affiliation(s)
- Alexandros Papadimitriou
- Renal Sciences and Integrative Chinese Medicine Laboratory, Department of Inflammation Biology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Paola Romagnani
- Department of Clinical and Experimental Biomedical Sciences, University of Florence, Florence, Italy
| | - Maria Lucia Angelotti
- Department of Clinical and Experimental Biomedical Sciences, University of Florence, Florence, Italy
| | - Mazhar Noor
- Renal Sciences and Integrative Chinese Medicine Laboratory, Department of Inflammation Biology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Jonathan Corcoran
- The Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Katie Raby
- University College London, UCL Centre for Nephrology, Royal Free Hospital, London, UK
| | - Patricia D Wilson
- University College London, UCL Centre for Nephrology, Royal Free Hospital, London, UK
| | - Joan Li
- Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
| | - Donald Fraser
- Wales Kidney Research Unit, Heath Park Campus, Cardiff, UK
| | - Remi Piedagnel
- National Institute for Health and Medical Research (INSERM), Unité Mixte de Recherche (UMR)-S1155, Tenon Hospital, Sorbonne Universités, Paris, France
| | - Bruce M Hendry
- Renal Sciences and Integrative Chinese Medicine Laboratory, Department of Inflammation Biology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Qihe Xu
- Renal Sciences and Integrative Chinese Medicine Laboratory, Department of Inflammation Biology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
| |
Collapse
|
4
|
Leipziger J, Praetorius H. Renal Autocrine and Paracrine Signaling: A Story of Self-protection. Physiol Rev 2020; 100:1229-1289. [PMID: 31999508 DOI: 10.1152/physrev.00014.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Autocrine and paracrine signaling in the kidney adds an extra level of diversity and complexity to renal physiology. The extensive scientific production on the topic precludes easy understanding of the fundamental purpose of the vast number of molecules and systems that influence the renal function. This systematic review provides the broader pen strokes for a collected image of renal paracrine signaling. First, we recapitulate the essence of each paracrine system one by one. Thereafter the single components are merged into an overarching physiological concept. The presented survey shows that despite the diversity in the web of paracrine factors, the collected effect on renal function may not be complicated after all. In essence, paracrine activation provides an intelligent system that perceives minor perturbations and reacts with a coordinated and integrated tissue response that relieves the work load from the renal epithelia and favors diuresis and natriuresis. We suggest that the overall function of paracrine signaling is reno-protection and argue that renal paracrine signaling and self-regulation are two sides of the same coin. Thus local paracrine signaling is an intrinsic function of the kidney, and the overall renal effect of changes in blood pressure, volume load, and systemic hormones will always be tinted by its paracrine status.
Collapse
Affiliation(s)
- Jens Leipziger
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| | - Helle Praetorius
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
| |
Collapse
|
5
|
Le Billan F, Amazit L, Bleakley K, Xue QY, Pussard E, Lhadj C, Kolkhof P, Viengchareun S, Fagart J, Lombès M. Corticosteroid receptors adopt distinct cyclical transcriptional signatures. FASEB J 2018; 32:5626-5639. [PMID: 29733691 DOI: 10.1096/fj.201800391rr] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) are two closely related hormone-activated transcription factors that regulate major pathophysiologic functions. High homology between these receptors accounts for the crossbinding of their corresponding ligands, MR being activated by both aldosterone and cortisol and GR essentially activated by cortisol. Their coexpression and ability to bind similar DNA motifs highlight the need to investigate their respective contributions to overall corticosteroid signaling. Here, we decipher the transcriptional regulatory mechanisms that underlie selective effects of MRs and GRs on shared genomic targets in a human renal cellular model. Kinetic, serial, and sequential chromatin immunoprecipitation approaches were performed on the period circadian protein 1 ( PER1) target gene, providing evidence that both receptors dynamically and cyclically interact at the same target promoter in a specific and distinct transcriptional signature. During this process, both receptors regulate PER1 gene by binding as homo- or heterodimers to the same promoter region. Our results suggest a novel level of MR-GR target gene regulation, which should be considered for a better and integrated understanding of corticosteroid-related pathophysiology.-Le Billan, F., Amazit, L., Bleakley, K., Xue, Q.-Y., Pussard, E., Lhadj, C., Kolkhof, P., Viengchareun, S., Fagart, J., Lombès, M. Corticosteroid receptors adopt distinct cyclical transcriptional signatures.
Collapse
Affiliation(s)
- Florian Le Billan
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Université Paris-Saclay, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche S1185, Le Kremlin-Bicêtre, France
| | - Larbi Amazit
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Université Paris-Saclay, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche S1185, Le Kremlin-Bicêtre, France.,Unité Mixte de Service 32, Institut Biomédical de Bicêtre, Le Kremlin-Bicêtre, France
| | - Kevin Bleakley
- Institut National de Recherche en Informatique et Automatique-Saclay, Palaiseau, France.,Département de Mathématiques d'Orsay, Orsay, France
| | - Qiong-Yao Xue
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital de Bicêtre, Service de Génétique Moléculaire, Pharmacogénomique et Hormonologie, Le Kremlin Bicêtre, France
| | - Eric Pussard
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital de Bicêtre, Service de Génétique Moléculaire, Pharmacogénomique et Hormonologie, Le Kremlin Bicêtre, France
| | - Christophe Lhadj
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Université Paris-Saclay, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche S1185, Le Kremlin-Bicêtre, France
| | - Peter Kolkhof
- Department of Cardiology Research, Bayer AG, Global Drug Discovery, Wuppertal, Germany
| | - Say Viengchareun
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Université Paris-Saclay, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche S1185, Le Kremlin-Bicêtre, France
| | - Jérôme Fagart
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Université Paris-Saclay, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche S1185, Le Kremlin-Bicêtre, France
| | - Marc Lombès
- INSERM, U1185, Le Kremlin-Bicêtre, France.,Université Paris-Sud, Université Paris-Saclay, Faculté de Médecine Paris-Sud, Unité Mixte de Recherche S1185, Le Kremlin-Bicêtre, France.,(AP-HP), Hôpital de Bicêtre, Service d'Endocrinologie et des Maladies de la Reproduction, Le Kremlin Bicêtre, France
| |
Collapse
|
6
|
Pirat C, Dacquet C, Leclerc V, Hennuyer N, Beucher-Gaudin M, Zanirato G, Géant A, Staels B, Ktorza A, Farce A, Caignard DH, Berthelot P, Lebegue N. Anti-diabetic activity of fused PPARγ-SIRT1 ligands with limited body-weight gain by mimicking calorie restriction and decreasing SGK1 expression. Eur J Med Chem 2017; 137:310-326. [DOI: 10.1016/j.ejmech.2017.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/31/2017] [Accepted: 06/02/2017] [Indexed: 12/27/2022]
|
7
|
Forschbach V, Goppelt-Struebe M, Kunzelmann K, Schreiber R, Piedagnel R, Kraus A, Eckardt KU, Buchholz B. Anoctamin 6 is localized in the primary cilium of renal tubular cells and is involved in apoptosis-dependent cyst lumen formation. Cell Death Dis 2015; 6:e1899. [PMID: 26448322 PMCID: PMC4632301 DOI: 10.1038/cddis.2015.273] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 08/11/2015] [Accepted: 08/27/2015] [Indexed: 02/07/2023]
Abstract
Primary cilia are antenna-like structures projected from the apical surface of various mammalian cells including renal tubular cells. Functional or structural defects of the cilium lead to systemic disorders comprising polycystic kidneys as a key feature. Here we show that anoctamin 6 (ANO6), a member of the anoctamin chloride channel family, is localized in the primary cilium of renal epithelial cells in vitro and in vivo. ANO6 was not essential for cilia formation and had no effect on in vitro cyst expansion. However, knockdown of ANO6 impaired cyst lumen formation of MDCK cells in three-dimensional culture. In the absence of ANO6, apoptosis was reduced and epithelial cells were incompletely removed from the center of cell aggregates, which form in the early phase of cystogenesis. In line with these data, we show that ANO6 is highly expressed in apoptotic cyst epithelial cells of human polycystic kidneys. These data identify ANO6 as a cilium-associated protein and suggest its functional relevance in cyst formation.
Collapse
Affiliation(s)
- V Forschbach
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - M Goppelt-Struebe
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - K Kunzelmann
- Department of Physiology, University of Regensburg, 93053 Regensburg, Germany
| | - R Schreiber
- Department of Physiology, University of Regensburg, 93053 Regensburg, Germany
| | - R Piedagnel
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1155, F-75005 Paris, France
- INSERM, UMR_S 1155, F-75005 Paris, France
| | - A Kraus
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - K-U Eckardt
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - B Buchholz
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| |
Collapse
|
8
|
Ribeiro A, Merkle M, Motamedi N, Nitschko H, Köppel S, Wörnle M. BK virus infection activates the TNFα/TNF receptor system in Polyomavirus-associated nephropathy. Mol Cell Biochem 2015; 411:191-9. [PMID: 26446017 DOI: 10.1007/s11010-015-2581-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 09/26/2015] [Indexed: 12/16/2022]
Abstract
Polyomavirus-associated nephropathy due to BK virus infection (BKVAN) is recognized as an important cause of significant kidney transplant dysfunction often leading to renal graft loss. The activation of innate immune defense mechanisms during BKVAN is still poorly understood and an altered regulation of inflammatory mediators by resident kidney cells upon viral infection can be expected to contribute to the onset and progression of disease. TNFα interacting with its receptors, TNF receptor 1 (TNFR1) and TNF receptor 2 (TNFR2), is largely accepted to be involved in viral responses, exhibiting both proinflammatory and immunosuppressive effects. Our aim was to examine the expressions of TNFα and TNFR1 and 2 in human collecting duct epithelial cells (HCDC) after infection with BKV as well as to study the effect of TNFα and poly(I:C), a synthetic analog of viral RNA, on the expressions of TNF receptors and proinflammatory cytokines and chemokines in HCDC. Quantitative RT-PCR analyses showed a downregulation of TNFα and an upregulation of both TNFR1 and 2 upon exposure of HCDC to the BK virus. TNFα stimulation induced the expressions of IL-6, IL-8, RANTES, and TNFR2. Poly(I:C) upregulated the expressions of both TNFR1 and TNFR2, a response that could be effectively blocked by siRNA to TLR3 and RIG-I, two double-stranded (ds) RNA receptors of the innate immune system. Poly(I:C)-dependent expression of TNFR2 but not TNFR1 was enhanced by TNFα. Taken together, our results suggest an involvement of TNF/TNFR system in virus-associated nephropathy.
Collapse
Affiliation(s)
- Andrea Ribeiro
- Medizinische Klinik und Poliklinik IV, Innenstadt, Klinikum der Universität München, Ziemssenstrasse 1, 80336, Munich, Germany
| | - Monika Merkle
- Medizinische Klinik und Poliklinik IV, Innenstadt, Klinikum der Universität München, Ziemssenstrasse 1, 80336, Munich, Germany
| | | | | | - Simone Köppel
- Medizinische Klinik und Poliklinik IV, Innenstadt, Klinikum der Universität München, Ziemssenstrasse 1, 80336, Munich, Germany
| | - Markus Wörnle
- Medizinische Klinik und Poliklinik IV, Innenstadt, Klinikum der Universität München, Ziemssenstrasse 1, 80336, Munich, Germany.
| |
Collapse
|
9
|
Le Billan F, Khan JA, Lamribet K, Viengchareun S, Bouligand J, Fagart J, Lombès M. Cistrome of the aldosterone-activated mineralocorticoid receptor in human renal cells. FASEB J 2015; 29:3977-89. [PMID: 26054365 DOI: 10.1096/fj.15-274266] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 05/26/2015] [Indexed: 01/01/2023]
Abstract
Aldosterone exerts its effects mainly by activating the mineralocorticoid receptor (MR), a transcription factor that regulates gene expression through complex and dynamic interactions with coregulators and transcriptional machinery, leading to fine-tuned control of vectorial ionic transport in the distal nephron. To identify genome-wide aldosterone-regulated MR targets in human renal cells, we set up a chromatin immunoprecipitation (ChIP) assay by using a specific anti-MR antibody in a differentiated human renal cell line expressing green fluorescent protein (GFP)-MR. This approach, coupled with high-throughput sequencing, allowed identification of 974 genomic MR targets. Computational analysis identified an MR response element (MRE) including single or multiple half-sites and palindromic motifs in which the AGtACAgxatGTtCt sequence was the most prevalent motif. Most genomic MR-binding sites (MBSs) are located >10 kb from the transcriptional start sites of target genes (84%). Specific aldosterone-induced recruitment of MR on the first most relevant genomic sequences was further validated by ChIP-quantitative (q)PCR and correlated with concomitant and positive aldosterone-activated transcriptional regulation of the corresponding gene, as assayed by RT-qPCR. It was notable that most MBSs lacked MREs but harbored DNA recognition motifs for other transcription factors (FOX, EGR1, AP1, PAX5) suggesting functional interaction. This work provides new insights into aldosterone MR-mediated renal signaling and opens relevant perspectives for mineralocorticoid-related pathophysiology.
Collapse
Affiliation(s)
- Florian Le Billan
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| | - Junaid A Khan
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| | - Khadija Lamribet
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| | - Say Viengchareun
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| | - Jérôme Bouligand
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| | - Jérôme Fagart
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| | - Marc Lombès
- *Unité 1185, Institut National de la Santé et de la Recherche Médicale, Le Kremlin-Bicêtre, France; Faculté de Médecine Paris-Sud, Unité Mixte de Recherche-S1185, Université Paris-Sud, Le Kremlin-Bicêtre, France; and Service de Génétique Moléculaire, Pharmacogénétique et d'Hormonologie and Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France
| |
Collapse
|
10
|
Ribeiro A, Wörnle M, Motamedi N, Anders HJ, Gröne EF, Nitschko H, Kurktschiev P, Debiec H, Kretzler M, Cohen CD, Gröne HJ, Schlöndorff D, Schmid H. Activation of innate immune defense mechanisms contributes to polyomavirus BK-associated nephropathy. Kidney Int 2012; 81:100-11. [PMID: 21918500 DOI: 10.1038/ki.2011.311] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Polyomavirus-associated nephropathy (PVAN) is a significant complication after kidney transplantation, often leading to premature graft loss. In order to identify antiviral responses of the renal tubular epithelium, we studied activation of the viral DNA and the double-stranded RNA (dsRNA) sensors Toll-like receptor 3 (TLR3) and retinoic acid inducible gene-I (RIG-I) in allograft biopsy samples of patients with PVAN, and in human collecting duct cells in culture after stimulation by the dsRNA mimic polyriboinosinic:polyribocytidylic acid (poly(I:C)), cytokines, or infection with BK virus. Double staining using immunofluorescence for BK virus and TLR3 showed strong signals in epithelial cells of distal cortical tubules and the collecting duct. In biopsies microdissected to isolate tubulointerstitial lesions, TLR3 but not RIG-I mRNA expression was found to be increased in PVAN. Collecting duct cells in culture expressed TLR3 intracellularly, and activation of TLR3 and RIG-I by poly(I:C) enhanced expression of cytokine, chemokine, and IFN-β mRNA. This inflammatory response could be specifically blocked by siRNA to TLR3. Finally, infection of the collecting duct cells with BK virus enhanced the expression of cytokines and chemokines. This led to an efficient antiviral immune response with TLR3 and RIG-I upregulation without activation of IL-1β or components of the inflammasome pathway. Thus, PVAN activation of innate immune defense mechanisms through TLR3 is involved in the antiviral and anti-inflammatory response leading to the expression of proinflammatory cytokines and chemokines.
Collapse
Affiliation(s)
- Andrea Ribeiro
- Medizinische Poliklinik Campus Innenstadt, Klinikum der LMU, Munich, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Mutel E, Gautier-Stein A, Abdul-Wahed A, Amigó-Correig M, Zitoun C, Stefanutti A, Houberdon I, Tourette JA, Mithieux G, Rajas F. Control of blood glucose in the absence of hepatic glucose production during prolonged fasting in mice: induction of renal and intestinal gluconeogenesis by glucagon. Diabetes 2011; 60:3121-31. [PMID: 22013018 PMCID: PMC3219939 DOI: 10.2337/db11-0571] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Since the pioneering work of Claude Bernard, the scientific community has considered the liver to be the major source of endogenous glucose production in all postabsorptive situations. Nevertheless, the kidneys and intestine can also produce glucose in blood, particularly during fasting and under protein feeding. The aim of this study was to better define the importance of the three gluconeogenic organs in glucose homeostasis. RESEARCH DESIGN AND METHODS We investigated blood glucose regulation during fasting in a mouse model of inducible liver-specific deletion of the glucose-6-phosphatase gene (L-G6pc(-/-) mice), encoding a mandatory enzyme for glucose production. Furthermore, we characterized molecular mechanisms underlying expression changes of gluconeogenic genes (G6pc, Pck1, and glutaminase) in both the kidneys and intestine. RESULTS We show that the absence of hepatic glucose release had no major effect on the control of fasting plasma glucose concentration. Instead, compensatory induction of gluconeogenesis occurred in the kidneys and intestine, driven by glucagon, glucocorticoids, and acidosis. Moreover, the extrahepatic action of glucagon took place in wild-type mice. CONCLUSIONS Our study provides a definitive quantitative estimate of the capacity of extrahepatic gluconeogenesis to sustain fasting endogenous glucose production under the control of glucagon, regardless of the contribution of the liver. Thus, the current dogma relating to the respective role of the liver and of extrahepatic gluconeogenic organs in glucose homeostasis requires re-examination.
Collapse
|
12
|
Fernandes-Rosa FL, Hubert EL, Fagart J, Tchitchek N, Gomes D, Jouanno E, Benecke A, Rafestin-Oblin ME, Jeunemaitre X, Antonini SR, Zennaro MC. Mineralocorticoid receptor mutations differentially affect individual gene expression profiles in pseudohypoaldosteronism type 1. J Clin Endocrinol Metab 2011; 96:E519-27. [PMID: 21159846 DOI: 10.1210/jc.2010-1486] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Type 1 pseudohypoaldosteronism (PHA1), a primary form of mineralocorticoid resistance, is due to inactivating mutations of the NR3C2 gene, coding for the mineralocorticoid receptor (MR). OBJECTIVE The objective of the study was to assess whether different NR3C2 mutations have distinct effects on the pattern of MR-dependent transcriptional regulation of aldosterone-regulated genes. DESIGN AND METHODS Four MR mutations affecting residues in the ligand binding domain, identified in families with PHA1, were tested. MR proteins generated by site-directed mutagenesis were analyzed for their binding to aldosterone and were transiently transfected into renal cells to explore the functional effects on the transcriptional activity of the receptors by cis-trans-cotransactivation assays and by measuring the induction of endogenous gene transcription. RESULTS Binding assays showed very low or absent aldosterone binding for mutants MR(877Pro), MR(848Pro), and MR(947stop) and decreased affinity for aldosterone of MR(843Pro). Compared with wild-type MR, the mutations p.Leu843Pro and p.Leu877Pro displayed half-maximal aldosterone-dependent transactivation of reporter genes driven by mouse mammary tumor virus or glucocorticoid response element-2 dependent promoters, whereas MR(848Pro) and MR(947stop) nearly or completely lost transcriptional activity. Although MR(848Pro) and MR(947stop) were also incapable of inducing aldosterone-dependent gene expression of endogenous sgk1, GILZ, NDRG2, and SCNN1A, MR(843Pro) retained complete transcriptional activity on sgk1 and GILZ gene expression, and MR(877Pro) negatively affected the expression of sgk1, NDRG2, and SCNN1A. CONCLUSIONS Our data demonstrate that MR mutations differentially affect individual gene expression in a promoter-dependent manner. Investigation of differential gene expression profiles in PHA1 may allow a better understanding of the molecular substrate of phenotypic variability and to elucidate pathogenic mechanisms underlying the disease.
Collapse
Affiliation(s)
- Fábio L Fernandes-Rosa
- Department of Puericulture and Pediatrics, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto 14040-900, Brazil
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Bardet-Biedl syndrome highlights the major role of the primary cilium in efficient water reabsorption. Kidney Int 2011; 79:1013-25. [PMID: 21270763 DOI: 10.1038/ki.2010.538] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Studies of the primary cilium, now known to be present in all cells, have undergone a revolution, in part, because mutation of many of its proteins causes a large number of diseases, including cystic kidney disease. Bardet-Biedl syndrome (BBS) is an inherited ciliopathy characterized, among other dysfunctions, by renal defects for which the precise role of the cilia in kidney function remains unclear. We studied a cohort of patients with BBS where we found that these patients had a urinary concentration defect even when kidney function was near normal and in the absence of major cyst formation. Subsequent in vitro analysis showed that renal cells in which a BBS gene was knocked down were unciliated, but did not exhibit cell cycle defects. As the vasopressin receptor 2 is located in the primary cilium, we studied BBS-derived unciliated renal epithelial cells and found that they were unable to respond to luminal arginine vasopressin treatment and activate their luminal aquaporin 2. The ability to reabsorb water was restored by treating these unciliated renal epithelial cells with forskolin, a receptor-independent adenylate cyclase activator, showing that the intracellular machinery for water absorption was present but not activated. These findings suggest that the luminal receptor located on the primary cilium may be important for efficient transepithelial water absorption.
Collapse
|
14
|
Viengchareun S, Kamenicky P, Teixeira M, Butlen D, Meduri G, Blanchard-Gutton N, Kurschat C, Lanel A, Martinerie L, Sztal-Mazer S, Blot-Chabaud M, Ferrary E, Cherradi N, Lombès M. Osmotic stress regulates mineralocorticoid receptor expression in a novel aldosterone-sensitive cortical collecting duct cell line. Mol Endocrinol 2009; 23:1948-62. [PMID: 19846540 DOI: 10.1210/me.2009-0095] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Aldosterone effects are mediated by the mineralocorticoid receptor (MR), a transcription factor highly expressed in the distal nephron. Given that MR expression level constitutes a key element controlling hormone responsiveness, there is much interest in elucidating the molecular mechanisms governing MR expression. To investigate whether hyper- or hypotonicity could affect MR abundance, we established by targeted oncogenesis a novel immortalized cortical collecting duct (CCD) cell line and examined the impact of osmotic stress on MR expression. KC3AC1 cells form domes, exhibit a high transepithelial resistance, express 11beta-hydroxysteroid dehydrogenase 2 and functional endogenous MR, which mediates aldosterone-stimulated Na(+) reabsorption through the epithelial sodium channel activation. MR expression is tightly regulated by osmotic stress. Hypertonic conditions induce expression of tonicity-responsive enhancer binding protein, an osmoregulatory transcription factor capable of binding tonicity-responsive enhancer response elements located in MR regulatory sequences. Surprisingly, hypertonicity leads to a severe reduction in MR transcript and protein levels. This is accompanied by a concomitant tonicity-induced expression of Tis11b, a mRNA-destabilizing protein that, by binding to the AU-rich sequences of the 3'-untranslated region of MR mRNA, may favor hypertonicity-dependent degradation of labile MR transcripts. In sharp contrast, hypotonicity causes a strong increase in MR transcript and protein levels. Collectively, we demonstrate for the first time that optimal adaptation of CCD cells to changes in extracellular fluid composition is accompanied by drastic modification in MR abundance via transcriptional and posttranscriptional mechanisms. Osmotic stress-regulated MR expression may represent an important molecular determinant for cell-specific MR action, most notably in renal failure, hypertension, or mineralocorticoid resistance.
Collapse
|
15
|
Bengatta S, Arnould C, Letavernier E, Monge M, de Préneuf HM, Werb Z, Ronco P, Lelongt B. MMP9 and SCF protect from apoptosis in acute kidney injury. J Am Soc Nephrol 2009; 20:787-97. [PMID: 19329763 DOI: 10.1681/asn.2008050515] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Apoptosis of tubular epithelial cells is a hallmark of acute kidney injury (AKI), but the cellular events preceding apoptosis in this setting are incompletely understood. Because matrix metalloproteinase 9 (MMP9) degrades matrix components involved in cell survival, we studied the role of MMP9 in AKI. In the mouse model of folic acid-induced AKI, we observed a marked increase of MMP9 activity in the S3 segment of the proximal tubule (S3PT), correlating with the apoptotic phase. MMP9 deficiency increased apoptosis and the severity of renal lesions and substantially delayed recovery of renal function. MMP9-/- mice exhibited significant apoptosis in the S3PT and the intercalated cells of the collecting duct (I-CD), whereas wild-type mice exhibited none in these segments. Stem cell factor (SCF), an MMP9 substrate, was identified in the S3PT, and its receptor, c-Kit, was expressed in both the S3PT and I-CD. MMP9 released the soluble form of SCF (sSCF) from kidney cells in vivo and in vitro. In addition, SCF inhibited apoptosis of tubular cells in vitro, rescued MMP9-/- S3PT and I-CD from apoptosis in vivo, and improved renal function. An ischemia-reperfusion model of AKI produced similar results. In patients with AKI, urinary sSCF increased with acute tubular necrosis but not with prerenal azotemia. In conclusion, these data show that MMP9 protects the S3 segment of the proximal tubule and the I-CD from apoptosis in AKI, most likely by releasing sSCF.
Collapse
|
16
|
Bens M, Vandewalle A. Cell models for studying renal physiology. Pflugers Arch 2008; 457:1-15. [DOI: 10.1007/s00424-008-0507-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 03/22/2008] [Indexed: 12/24/2022]
|
17
|
Michell A, Debnam E, Unwin R. Regulation of Renal Function by the Gastrointestinal Tract: Potential Role of Gut-Derived Peptides and Hormones. Annu Rev Physiol 2008; 70:379-403. [DOI: 10.1146/annurev.physiol.69.040705.141330] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A.R. Michell
- Department of Biochemical Pharmacology, William Harvey Research Institute, St. Bartholomew's Hospital Medical School, London EC1M 6BQ, United Kingdom;
| | - E.S. Debnam
- Department of Physiology, Royal Free and University College Medical School, London NW3 2PF, United Kingdom;
| | - R.J. Unwin
- Department of Physiology, Royal Free and University College Medical School, London NW3 2PF, United Kingdom;
- Centre for Nephrology, Royal Free and University College Medical School, London NW3 2PF, United Kingdom;
| |
Collapse
|
18
|
Bens M, Chassin C, Vandewalle A. Regulation of NaCl transport in the renal collecting duct: lessons from cultured cells. Pflugers Arch 2006; 453:133-46. [PMID: 16937117 DOI: 10.1007/s00424-006-0123-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 06/14/2006] [Accepted: 06/19/2006] [Indexed: 11/29/2022]
Abstract
The fine control of NaCl absorption regulated by hormones takes place in the distal nephron of the kidney. In collecting duct principal cells, the epithelial sodium channel (ENaC) mediates the apical entry of Na(+), which is extruded by the basolateral Na(+),K(+)-ATPase. Simian virus 40-transformed and "transimmortalized" collecting duct cell lines, derived from transgenic mice carrying a constitutive, conditionally, or tissue-specific promoter-regulated large T antigen, have been proven to be valuable tools for studying the mechanisms controlling the cell surface expression and trafficking of ENaC and Na(+),K(+)-ATPase. These cell lines have made it possible to identify sets of aldosterone- and vasopressin-stimulated proteins, and have provided new insights into the concerted mechanism of action of serum- and glucocorticoid-inducible kinase 1 (Sgk1), ubiquitin ligase Nedd4-2 (neural precursor cell-expressed, developmentally down-regulated protein 4-2), and 14-3-3 regulatory proteins in modulating ENaC-mediated Na(+) currents. Epidermal growth factor and induced leucine zipper protein have also been shown to repress and stimulate ENaC-dependent Na(+) absorption, respectively, by activating or repressing the mitogen-activated protein kinase externally regulated kinase(1/2). Overall, these findings have provided evidence suggesting that multiple pathways are involved in regulating NaCl absorption in the distal nephron.
Collapse
Affiliation(s)
- M Bens
- INSERM, U773, Centre de Recherche Biomédicale Bichat-Beaujon, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, BP 416, 75870 Paris, France
| | | | | |
Collapse
|
19
|
Abstract
In this review we outline the unique effects of the autacoid adenosine in the kidney. Adenosine is present in the cytosol of renal cells and in the extracellular space of normoxic kidneys. Extracellular adenosine can derive from cellular adenosine release or extracellular breakdown of ATP, AMP, or cAMP. It is generated at enhanced rates when tubular NaCl reabsorption and thus transport work increase or when hypoxia is induced. Extracellular adenosine acts on adenosine receptor subtypes in the cell membranes to affect vascular and tubular functions. Adenosine lowers glomerular filtration rate (GFR) by constricting afferent arterioles, especially in superficial nephrons, and acts as a mediator of the tubuloglomerular feedback, i.e., a mechanism that coordinates GFR and tubular transport. In contrast, it leads to vasodilation in deep cortex and medulla. Moreover, adenosine tonically inhibits the renal release of renin and stimulates NaCl transport in the cortical proximal tubule but inhibits it in medullary segments including the medullary thick ascending limb. These differential effects of adenosine are subsequently analyzed in a more integrative way in the context of intrarenal metabolic regulation of kidney function, and potential pathophysiological consequences are outlined.
Collapse
Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California, San Diego, USA
| | | | | |
Collapse
|
20
|
Hills CE, Bland R, Bennett J, Ronco PM, Squires PE. High Glucose Up-Regulates ENaC and SGK1 Expression in HCD-Cells. Cell Physiol Biochem 2006; 18:337-46. [PMID: 17170520 DOI: 10.1159/000097611] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIM Diabetic nephropathy is associated with progressive renal damage, leading to impaired function and end-stage renal failure. Secondary hypertension stems from a deranged ability of cells within the kidney to resolve and appropriately regulate sodium resorption in response to hyperglycaemia. However, the mechanisms by which glucose alters sodium re-uptake have not been fully characterised. METHODS Here we present RT-PCR, western blot and immunocytochemistry data confirming mRNA and protein expression of the serum and glucocorticoid inducible kinase (SGK1) and the alpha conducting subunit of the epithelial sodium channel (ENaC) in a model in vitro system of the human cortical collecting duct (HCD). We examined changes in expression of these elements in response to glucose challenge, designed to mimic hyperglycaemia associated with type 2 diabetes mellitus. Changes in Na+ concentration were assessed using single-cell microfluorimetry. RESULTS Incubation with glucose, the Ca2+-ionophore ionomycin and the cytokine TGF-beta1 were all found to evoke significant and time-dependent increases in both SGK1 and alphaENaC protein expression. These molecular changes were correlated to an increase in Na+-uptake at the single-cell level. CONCLUSION Together these data offer a potential explanation for glucose-evoked Na+-resorption and a potential contributory role of SGK1 and ENaCs in development of secondary hypertension, commonly linked to diabetic nephropathy.
Collapse
Affiliation(s)
- Claire E Hills
- Molecular Physiology, Biomedical Research Institute, Department of Biological Sciences, University of Warwick, Coventry, UK
| | | | | | | | | |
Collapse
|
21
|
Sartorato P, Cluzeaud F, Fagart J, Viengchareun S, Lombès M, Zennaro MC. New Naturally Occurring Missense Mutations of the Human Mineralocorticoid Receptor Disclose Important Residues Involved in Dynamic Interactions with Deoxyribonucleic Acid, Intracellular Trafficking, and Ligand Binding. Mol Endocrinol 2004; 18:2151-65. [PMID: 15192075 DOI: 10.1210/me.2003-0408] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have investigated the functional consequences of three naturally occurring amino acid substitutions of the human mineralocorticoid receptor (hMR). These mutations are located in the DNA-binding domain and the ligand-binding domain (LBD) and are associated with autosomal dominant or sporadic type I pseudohypoaldosteronism. All mutant receptors bound specifically to glucocorticoid-responsive elements but presented modified transcriptional properties. The DNA-binding domain mutant G633R, which possesses a normal affinity for a glucocorticoid-responsive element, displayed altered interaction with, and a reduced dissociation rate from, DNA. Its intracellular localization in the absence of hormone was predominantly nuclear in comparison with predominant cytoplasmic location of hMR. Hormone-dependent nuclear cluster formation was comparable to wild-type hMR. These results and the three-dimensional modeling of the interaction of R633 with DNA suggest that altered interaction dynamics with DNA as well as modified intracellular localization may be responsible for submaximal transcriptional potency of hMR. Two LBD mutations, Q776R and L979P, were also investigated. Our data confirm the fundamental role of amino acid Q776 for anchoring the C3 ketone group of steroids in the ligand-binding pocket. Analysis of LBD conformation of mutant P979 demonstrates the relevance of hydrophobic interactions in the extreme C-terminal tail of the hMR for the correct ligand-binding competent state of the receptor. Our data underline the importance of studying naturally occurring mutants to identify crucial residues involved in hMR function.
Collapse
Affiliation(s)
- Paola Sartorato
- Institut National de la Santé et de la Recherche Médicale U478, Faculté de Médecine Xavier Bichat, B.P. 416, 16, rue Henri Huchard, 75870 Paris Cedex 18, France
| | | | | | | | | | | |
Collapse
|
22
|
Hong G, Lockhart A, Davis B, Rahmoune H, Baker S, Ye L, Thompson P, Shou Y, O'Shaughnessy K, Ronco P, Brown J. PPARgamma activation enhances cell surface ENaCalpha via up-regulation of SGK1 in human collecting duct cells. FASEB J 2003; 17:1966-8. [PMID: 12923071 DOI: 10.1096/fj.03-0181fje] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent transcription factor that belongs to the nuclear receptor family that plays a critical role in adipocyte differentiation and lipid metabolism. Here we report for the first time that PPARgamma is expressed in human renal cortical collecting ducts (CCD), segments of the nephor involved in regulation of sodium and water homeostasis via action of the epithelial sodium channel (ENaC). ENaC activity is regulated by the hormones aldosterone and insulin, primarily through co-ordinate actions on serum and glucocorticoid regulated kinase 1 (SGK1). We show that SGK1 activity is stimulated by treatment of a human CCD cell line with PPARgamma agonists, paralleled by an increase in SGK1 mRNA that is abolished by pretreatment with a specific PPARgamma antagonist, and that this leads to increased levels of cell surface ENaCalpha. Electrophoretic mobility shift assays suggest that these effects are caused by binding of PPARgamma to a specific response element in the SGK1 promoter. Our results identify SGK1 as a target for PPARgamma and suggest a novel role for PPARgamma in regulation of sodium re-absorption in the CCD via stimulation of ENaC activity. This pathway may play a role in sodium retention caused by activation of PPARgamma in man.
Collapse
Affiliation(s)
- Guizhu Hong
- Translational Medicine and Technology, GlaxoSmithKline, ACCI, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 2GG, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Tallec LPL, Kirsh O, Lecomte MC, Viengchareun S, Zennaro MC, Dejean A, Lombès M. Protein inhibitor of activated signal transducer and activator of transcription 1 interacts with the N-terminal domain of mineralocorticoid receptor and represses its transcriptional activity: implication of small ubiquitin-related modifier 1 modification. Mol Endocrinol 2003; 17:2529-42. [PMID: 14500761 DOI: 10.1210/me.2003-0299] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Molecular mechanisms underlying mineralocorticoid receptor (MR)-mediated gene expression are not fully understood but seem to largely depend upon interactions with specific coregulators. To identify novel human MR (hMR) molecular partners, yeast two-hybrid screenings performed using the N-terminal domain as bait, allowed us to isolate protein inhibitor of activated signal transducer and activator of transcription (PIAS)1 and PIASxbeta, described as SUMO (small ubiquitin-related modifier) E3-ligases. Specific interaction between PIAS1 and hMR was confirmed by glutathione-S-transferase pull-down experiments and N-terminal subdomains responsible for physical contacts were delineated. Transient transfections demonstrated that PIAS1 is a corepressor of aldosterone-activated MR transactivation but has no significant effect on human glucocorticoid receptor transactivation. The agonist or antagonist nature of the bound ligand also determines PIAS1 corepressive action. We provided evidence that PIAS1 conjugated SUMO-1 to hMR both in vitro and in vivo. Deciphering the unique sumoylation pattern of hMR, which possesses five consensus SUMO-1 binding sites, by combinatorial lysine substitutions, revealed a major impact of sumoylation on hMR properties. Using a murine mammary tumor virus promoter, PIAS1 action was independent of sumoylation whereas with glucocorticoid response element promoter, PIAS1 corepressive action depended on hMR sumoylation status. Taken together, our results identify a novel function for PIAS1 which interacts with the N-terminal domain of hMR and represses its ligand-dependent transcriptional activity, at least in part, through SUMO modifications.
Collapse
Affiliation(s)
- Laurent Pascual-Le Tallec
- Institut National de la Santé et de la Recherche Médicale, U478, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, 75870 Paris cedex 18, France
| | | | | | | | | | | | | |
Collapse
|
24
|
Régnauld K, Nguyen QD, Vakaet L, Bruyneel E, Launay JM, Endo T, Mareel M, Gespach C, Emami S. G-protein alpha(olf) subunit promotes cellular invasion, survival, and neuroendocrine differentiation in digestive and urogenital epithelial cells. Oncogene 2002; 21:4020-31. [PMID: 12037684 DOI: 10.1038/sj.onc.1205498] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2001] [Revised: 03/06/2002] [Accepted: 03/18/2002] [Indexed: 12/26/2022]
Abstract
The heterotrimeric G-protein subunits Galpha and Gbetagamma are involved in cellular transformation and tumor development. Here, we report the expression of Galpha(olf) in human digestive and urogenital epithelial cells using RT-PCR and Western blot. When the constitutively activated form of Galpha(olf)Q214L (AGalpha(olf)) was stably transfected in canine kidney MDCKts.src and human colonic HCT-8/S11 epithelial cells, it induced cellular invasion in collagen gels. AGalpha(olf)-mediated invasion was abrogated by agonists of platelet activating factor receptors (PAF-R) and protease-activated receptors -1 (PAR-1), pharmacological inhibitors of PI3'-Kinase (wortmannin), protein kinase C (Gö6976 and GF109203X), Rho GTPase (C3T exoenzyme), but was independent of protein kinase A. Accordingly, the invasive phenotype induced by AGalpha(olf) in HCT-8/S11 cells was reversed by the RhoA antagonist RhoD (G26V). Although AGalpha(olf) protected MDCKts.src cells against serum starvation-mediated apoptosis via a Rho-independent pathway, both AGalpha(olf) and Rho inhibition by C3T induced neuroendocrine-like differentiation linked to extensive neurite outgrowth and parathyroid hormone-related protein expression in human prostatic LNCaP-AGalpha(olf) cells. Since prostate tumors with a larger neuroendocrine cell population display increased invasiveness, persistent activation of the G-protein alpha(olf) may exert convergent adverse effects on cellular invasion and survival in solid tumors during the neoplastic progression towards metastasis. doi:10.1038/sj.onc.1205498
Collapse
Affiliation(s)
- Karine Régnauld
- INSERM U482, Signal transduction and cellular functions in Diabetes and Digestive Cancers, Hôpital Saint-Antoine, 75571 Paris Cedex 12, France
| | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Nawrocki AR, Goldring CE, Kostadinova RM, Frey FJ, Frey BM. In vivo footprinting of the human 11beta-hydroxysteroid dehydrogenase type 2 promoter: evidence for cell-specific regulation by Sp1 and Sp3. J Biol Chem 2002; 277:14647-56. [PMID: 11850421 DOI: 10.1074/jbc.m111549200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
11beta-Hydroxysteroid dehydrogenase type 2 is selectively expressed in aldosterone target tissues, where it confers aldosterone selectivity for the mineralocorticoid receptor by inactivating 11beta-hydroxyglucocorticoids with a high affinity for the mineralocorticoid receptor. The present investigation aimed to elucidate the mechanisms accounting for the rigorous control of the HSD11B2 gene in humans. Using dimethyl sulfate in vivo footprinting via ligation-mediated PCR, we identified potentially important regions for HSD11B2 regulation in human cell lines: two GC-rich regions in the first exon (I and II) and two upstream elements (III and IV). The footprints suggest a correlation between the extent of in vivo protein occupancy at three of these regions (I, II, and III) and the rate of HSD11B2 transcription in cells with high (SW620), intermediate (HCD, MCF-7, and HK-2), or low HSD11B2 mRNA levels (SUT). Moreover, gel shift assays with nuclear extracts from these cell lines revealed that decreased HSD11B2 expression is related to a decreased binding activity with oligonucleotides containing the putative regulatory elements. Antibody supershifts identified the majority of the components of the binding complexes as the transcription factors Sp1 and Sp3. Finally, transient transfections with various deletion mutant reporters define positive regulatory elements that might account for basal and selective expression of 11beta-hydroxysteroid dehydrogenase type 2.
Collapse
Affiliation(s)
- Andrea R Nawrocki
- Division of Nephrology and Hypertension, Department of Internal Medicine, University Hospital of Berne, CH-3010 Berne, Switzerland.
| | | | | | | | | |
Collapse
|
26
|
Régnauld KL, Leteurtre E, Gutkind SJ, Gespach CP, Emami S. Activation of adenylyl cyclases, regulation of insulin status, and cell survival by G(alpha)olf in pancreatic beta-cells. Am J Physiol Regul Integr Comp Physiol 2002; 282:R870-80. [PMID: 11832410 DOI: 10.1152/ajpregu.00374.2001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Because we recently identified the G(alpha)olf subunit in rat pancreatic beta-cells, we investigated the downstream effectors and the biological functions of this G protein in HEK-293T cells and the insulin-secreting mouse betaTC-3 cell line. With the use of transient transfection of HEK-293T cells with constitutively activated G(alpha)olf (G(alpha)olfQ214L, i.e., AG(alpha)olf), together with expression vectors encoding the adenylyl cyclase (AC) isoforms (AC-I to -VIII and soluble AC), compared with cotransfections using AG(alphas) (G(alphas)R201C), we observed that AG(alpha)olf preferentially activates AC-I and -VIII, which are also expressed in beta-cells. Stable overexpression of wild-type or AG(alpha)olf in betaTC-3 cells resulted in partial attenuation of insulin secretion and biosynthesis, suggesting that chronic activation of the G(alpha)olf-signaling pathway is associated with beta-cell desensitization. In agreement, transfected betaTC-3 cells present a decreased insulin content with respect to parental cells, whereas the proinsulin convertases PC-1 and PC-2 were unaffected. Furthermore, betaTC-3-AG(alpha)olf cells are resistant to serum starvation-induced apoptosis. Our findings suggest that G(alpha)olf is involved in insulin status, cell survival, and regeneration of the insulin-secreting beta-cells during development and diabetes.
Collapse
Affiliation(s)
- Karine L Régnauld
- Institut National de la Santé et de la Recherche Médicale U482, Signal Transduction and Cellular Function in Diabetes and Digestive Cancers, Saint-Antoine Hospital, 75571 Paris Cedex 12, France
| | | | | | | | | |
Collapse
|
27
|
Bland R, Zehnder D, Hughes SV, Ronco PM, Stewart PM, Hewison M. Regulation of vitamin D-1alpha-hydroxylase in a human cortical collecting duct cell line. Kidney Int 2001; 60:1277-86. [PMID: 11576342 DOI: 10.1046/j.1523-1755.2001.00966.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Recent studies have shown that renal expression of 25-hydroxyvitamin D3-1alpha-hydroxylase (1alpha-OHase) is not restricted to proximal tubules. To investigate the significance of this expression, we characterized the regulation of 1alpha-OHase expression and activity in a human cortical collecting duct cell line (HCD). METHODS Expression of 1alpha-OHase mRNA and protein was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses. Enzyme activity was quantified using 25-hydroxyvitamin D3 as the substrate; conversion to 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and 24,25-dihydroxyvitamin D3 was then determined by thin-layer chromatography. RESULTS HCD cells expressed mRNA and protein for 1alpha-OHase. However, basal 1,25(OH)2D3 production was lower than that observed in proximal tubule HKC-8 cells. In both cell lines, synthesis of 1,25(OH)2D3 was increased by forskolin, parathyroid hormone, and low calcium medium. Conversely, treatment with 1,25(OH)2D3 itself decreased 1alpha-OHase activity. This effect was more pronounced in HCD cells, which also demonstrated significantly higher levels of 24-hydroxylase activity. The most striking induction of 1alpha-OHase activity was observed in the HCD cells following incubation with lipopolysaccharide, which was coincident with the expression of mRNA for both CD14 and Toll-like receptor 4. CONCLUSIONS These results highlight the capacity for synthesis of 1,25(OH)2D3 in cells from more distal areas of the nephron. However, more sensitive feedback regulation and immune induction of 1alpha-OHase in the HCD cells suggest a more localized role for 1,25(OH)2D3 production in the distal nephron.
Collapse
Affiliation(s)
- R Bland
- Division of Medical Sciences, The University of Birmingham, Queen Elizabeth Hospital, Birmingham, England, United Kingdom
| | | | | | | | | | | |
Collapse
|
28
|
Helbert MJ, Dauwe SE, De Broe ME. Flow cytometric immunodissection of the human distal tubule and cortical collecting duct system. Kidney Int 2001; 59:554-64. [PMID: 11168937 DOI: 10.1046/j.1523-1755.2001.059002554.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In recent years, considerable efforts were drawn to isolate human distal tubule (DT) and collecting duct (CD) cells with more or less success. Here, we present a procedure for isolating human DT cells [thick ascending limb (TAL)/distal convoluted tubule (DCT)] and CD system cells (connecting tubule/initial CD) as separate populations within the same kidney specimen, applying monoclonal antibodies in fluorescence-activated cell sorting (FACS) and culturing them. METHODS We tested antibodies directed against the DT/CD system antigens, epithelial membrane antigen (EMA) and L1-cell adhesion molecule (L1-CAM). Segmental and subsegmental expressions were first assessed by using morphologic and histotopographic criteria, and by comparing sections with adjacent sections stained for expression of well-defined distal subsegment-specific markers. Immunoreactive cells were further characterized by dual immunostaining using cell type-specific markers. As a second step, cells obtained by collagenase digestion of normal renal cortical tissue were flow sorted following labeling with aforementioned antibodies and cultured. RESULTS EMA expression was found on all cells present in the DT and in the CD system. Its expression was most abundant in TAL and from thereon decreased gradually along the course of the DT and CD system. Flow sorting of all EMA-expressing cells resulted in identification/isolation of DT and CD system cells as a heterogeneous mixture. Flow sorting of only the most strongly EMA-positive cells allowed purification of DT cells only, mainly TAL cells as shown by Tamm-Horsfall protein expression on> 80% of sorted cells. L1-CAM was expressed in only the CD system, and sorting of all L1-CAM-positive cells allowed> 95% purification of CD system cells (connecting tubule/cortical CD). Primary cultures of DT and CD system cells rapidly developed into confluent monolayers, and retained antigenic and functional properties inherent to their segments of origin. CONCLUSION Our study presents a procedure for isolating and culturing pure populations of human DT cells and CD system cells as separate populations, using antibodies to the best available markers in FACS.
Collapse
Affiliation(s)
- M J Helbert
- Department of Nephrology, University of Antwerp, Belgium
| | | | | |
Collapse
|
29
|
Sciorsci RL, Bianchi P, Minoia P. High levels of endorphin and related pathologies of veterinary concern. A review. Immunopharmacol Immunotoxicol 2000; 22:575-626. [PMID: 11105777 DOI: 10.3109/08923970009016428] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The authors report information about endogenous opioid peptides (EOP), receptors, antagonists and their interference with pain, stress, endocrine and immune system. A relationship between EOP and calcium homeostasis, both at extracellular and intracellular level, has been observed. In vitro, beta-endorphin exerts different actions through calcium channel functionality in epithelial cells. In rat aorta and cerebral cortex: beta-endorphin or Naloxone alternatively influence oocyte maturation through the mu-receptor gene expression and intracellular calcium concentration in granulosa and cumulus cells. Calcium channel block is removed by administrating Naloxone and calcium. In vivo, Naloxone and calcium removes EOP induced apoptosis in granulosa cells; is the most safe therapy in cow's milk fever; allow to remove ovarian follicular cysts. A negative influence of opioids on immune response after vaccination was established; EOP-related metabolic problems in post-partum cows. Abnormal intestinal motility, in which a Ca++ influence is well known, can be removed by Naloxone and calcium administration. Calcium-related function and neuromodulation must be re-evaluated since high level of EOP are involved in many pathologies through their influence on calcium activity. The use of calcium salts and Naloxone offers a safe and supplementary therapeutical possibility, active in any condition of altered endogenous opioids.
Collapse
Affiliation(s)
- R L Sciorsci
- Department of Veterinary and Agro-Alimentary Sciences, Veterinary Medicine, University of Teramo, Italy
| | | | | |
Collapse
|
30
|
Calmont A, Reichwald K, Ronco P, Rossert J. Identification of a short cis-acting element in the human vasopressin type 2 receptor gene which confers high-level expression of a reporter gene specifically in collecting duct cells. Mol Endocrinol 2000; 14:1682-95. [PMID: 11043582 DOI: 10.1210/mend.14.10.0540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In the kidney, water reabsorption is mainly regulated by the binding of arginine vasopressin to vasopressin type 2 (V2) receptors. These receptors are expressed selectively in principal cells of the collecting ducts. To identify molecular mechanisms responsible for the cell-specific expression of the V2 receptor, we have analyzed the proximal promoter of the corresponding gene. We report the identification of a 33-bp enhancer [collecting duct tissue-specific element 1 (CSE1)] that induced high levels of expression of the luciferase reporter gene in three collecting duct cell lines, but not in other renal cell lines. In gel shift assays, CSE1 bound a DNA-binding protein expressed selectively in collecting duct cell lines, and a 7-bp mutation, which abolished the activity of CSE1 in transient transfection experiments, also abolished the binding of this protein. Furthermore, decoy experiments performed using CSE1 showed that this sequence was involved not only in the expression of a construct containing 4.2 kb of the V2 receptor proximal promoter, but also in the expression of the endogenous V2 receptor gene. CSE1 appears to act mostly by counteracting the inhibitory effects of a strong ubiquitous repressor element that we called CIE1. Collectively, these results identify the first functional collecting duct-specific cis-acting element.
Collapse
|
31
|
Agarwal AK. Expression of HSD11K (NAD+ dependent 11beta-hydroxysteroid dehydrogenase) promoter constructs in renal cell lines. Endocr Res 2000; 26:289-302. [PMID: 10921454 DOI: 10.3109/07435800009066168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The kidney (11-HSD2 or 11-HSDK) isozyme of 11beta-hydroxysteroid dehydrogenase confers specificity for aldosterone on mineralocorticoid receptors in target tissues. In rodent kidney, this isozyme is expressed mainly in cortical collecting ducts and is undetectable in proximal tubules. Using mouse M-1 and rabbit RCD cortical collecting duct cells, we analyzed the 5'-flanking region of the human HSD11K gene encoding this enzyme in an attempt to identify transcriptional regulatory elements responsible for gene expression in the kidney. M-1 and RCD cells had high levels of NAD+ dependent 11-HSD activity with corticosterone as the substrate. Luciferase reporter constructs containing 1785 or 327 nucleotides (nt) upstream of the initiator ATG codon were expressed at similar levels in each cell line, but deletion to 167 nt almost completely abolished expression in both cell types. This region is GC-rich and contain Sp1 binding sites. Electrophoretic mobility shift assays of the region containing the putative Sp1 sites showed several DNA-protein complexes in both the cell types. Mutations of the Sp1 sites decreased transcriptional activity in M-1 cells; however, these mutations had a marginal effect in the RCD cells. These results suggest that elements controlling renal cell type expression are located in the proximal 327 nucleotides of the 5' flanking region of HSD11K.
Collapse
Affiliation(s)
- A K Agarwal
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9063, USA.
| |
Collapse
|
32
|
Vandewalle A, Bens M, Duong Van Huyen JP. Immortalized kidney epithelial cells as tools for hormonally regulated ion transport studies. Curr Opin Nephrol Hypertens 1999; 8:581-7. [PMID: 10541221 DOI: 10.1097/00041552-199909000-00009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The development of transgenic mice carrying the simian virus-40 large T antigen gene or the temperature-sensitive simian virus-40 large T antigen gene, either alone or placed under the control of the 5'-regulatory regions of tissue-specific or ubiquitous genes, has permitted the production of differentiated, polarized kidney epithelial cells. This review covers the immortalized cell lines issued from the various parts of the renal tubule and, in particular, the recently established collecting duct cell lines that have been used as ex-vivo cell models to analyze the regulation of ion transport processes by hormones.
Collapse
Affiliation(s)
- A Vandewalle
- Institut National de la Santé et de la Recherche Médicale, Unité 478, Institut Fédératif de Recherche 02, Faculté de Médecine Xavier Bichat, Paris, France.
| | | | | |
Collapse
|
33
|
Debiec H, Christensen EI, Ronco PM. The cell adhesion molecule L1 is developmentally regulated in the renal epithelium and is involved in kidney branching morphogenesis. J Cell Biol 1998; 143:2067-79. [PMID: 9864376 PMCID: PMC2175226 DOI: 10.1083/jcb.143.7.2067] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We immunopurified a surface antigen specific for the collecting duct (CD) epithelium. Microsequencing of three polypeptides identified the antigen as the neuronal cell adhesion molecule L1, a member of the immunoglobulin superfamily. The kidney isoform showed a deletion of exon 3. L1 was expressed in the mesonephric duct and the metanephros throughout CD development. In the adult CD examined by electron microscopy, L1 was not expressed on intercalated cells but was restricted to CD principal cells and to the papilla tall cells. By contrast, L1 appeared late in the distal portion of the elongating nephron in the mesenchymally derived epithelium and decreased during postnatal development. Immunoblot analysis showed that expression, proteolytic cleavage, and the glycosylation pattern of L1 protein were regulated during renal development. L1 was not detected in epithelia of other organs developing by branching morphogenesis. Addition of anti-L1 antibody to kidney or lung organotypic cultures induced dysmorphogenesis of the ureteric bud epithelium but not of the lung. These results suggest a functional role for L1 in CD development in vitro. We further postulate that L1 may be involved in the guidance of developing distal tubule and in generation and maintenance of specialized cell phenotypes in CD.
Collapse
Affiliation(s)
- H Debiec
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 489, Hôpital Tenon, 75020 Paris, France.
| | | | | |
Collapse
|
34
|
Thomas CP, Auerbach S, Stokes JB, Volk KA. 5' heterogeneity in epithelial sodium channel alpha-subunit mRNA leads to distinct NH2-terminal variant proteins. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:C1312-23. [PMID: 9612219 DOI: 10.1152/ajpcell.1998.274.5.c1312] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The amiloride-sensitive epithelial sodium channel (ENaC) is composed of three subunits: alpha, beta, and gamma. The human alpha-ENaC subunit is expressed as at least two transcripts (N. Voilley, E. Lingueglia, G. Champigny, M. G. Mattei, R. Waldmann, M. Lazdunski, and P. Barbry. Proc. Natl. Acad. Sci. USA 91: 247-251, 1994). To determine the origin of these transcripts, we characterized the 5' end of the alpha-ENaC gene. Four transcripts that differ at their first exon were identified. Exon 1A splices to exon 2 to form the 5' end of alpha-ENaC1, whereas exon 1B arises separately and continues into exon 2 to form alpha-ENaC2. Other variant mRNAs, alpha-ENaC3 and alpha-ENaC4, are formed by activating 5' splice sites within exon 1B. Although alpha-ENaC3 and -4 did not change the open reading frame for alpha-ENaC, alpha-ENaC2 contains upstream ATGs that add 59 amino acids to the previous (alpha-ENaC1) protein. To address the significance of these isoforms, both proteins were expressed in Xenopus oocytes. The cRNA for each alpha-ENaC transcript when combined with beta- and gamma-ENaC cRNA reconstituted a low-conductance ion channel with amiloride-sensitive currents of similar characteristics. We have thus identified variant alpha-ENaC mRNAs that lead to functional ENaC peptides.
Collapse
Affiliation(s)
- C P Thomas
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, USA
| | | | | | | |
Collapse
|
35
|
Zennaro MC, Le Menuet D, Viengchareun S, Walker F, Ricquier D, Lombès M. Hibernoma development in transgenic mice identifies brown adipose tissue as a novel target of aldosterone action. J Clin Invest 1998; 101:1254-60. [PMID: 9502766 PMCID: PMC508679 DOI: 10.1172/jci1915] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Aldosterone is a major regulator of salt balance and blood pressure, exerting its effects via the mineralocorticoid receptor (MR). To analyze the regulatory mechanisms controlling tissue-specific expression of the human MR (hMR) in vivo, we have developed transgenic mouse models expressing the SV40 large T antigen (TAg) under the control of each of the two promoters of the hMR gene (P1 or P2). Unexpectedly, all five P1-TAg founder animals died prematurely from voluminous malignant liposarcomas originating from brown adipose tissue, as evidenced by the expression of the mitochondrial uncoupling protein ucp1, indicating that the proximal P1 promoter was transcriptionally active in brown adipocytes. No such hibernoma occurred in P2-TAg transgenic mice. Appropriate tissue-specific usage of P1 promoter sequences was confirmed by demonstrating the presence of endogenous MR in both neoplastic and normal brown adipose tissue. Several cell lines were derived from hibernomas; among them, the T37i cells can undergo terminal differentiation into brown adipocytes, which remain capable of expressing ucp1 upon adrenergic or retinoic acid stimulation. These cells possess endogenous functional MR, thus providing a new model to explore molecular mechanisms of mineralocorticoid action. Our data broaden the known functions of aldosterone and suggest a potential role for MR in adipocyte differentiation and regulation of thermogenesis.
Collapse
MESH Headings
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/pathology
- Aldosterone/metabolism
- Animals
- Antigens, Polyomavirus Transforming/genetics
- Blotting, Northern
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cloning, Molecular
- Gene Expression
- Histocytochemistry
- Humans
- Immunohistochemistry
- Ion Channels
- Lipoma/genetics
- Lipoma/metabolism
- Lipoma/pathology
- Liposarcoma/genetics
- Liposarcoma/metabolism
- Liposarcoma/pathology
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Transgenic
- Mitochondrial Proteins
- Polymerase Chain Reaction
- Promoter Regions, Genetic
- Receptors, Mineralocorticoid/genetics
- Receptors, Mineralocorticoid/metabolism
- Transcription, Genetic
- Triglycerides/analysis
- Triglycerides/metabolism
- Tumor Cells, Cultured
- Uncoupling Protein 1
Collapse
Affiliation(s)
- M C Zennaro
- INSERM U 246, Institut Fédératif de Recherche Cellules Epithéliales, Faculté de Mé decine Xavier Bichat, Paris, France
| | | | | | | | | | | |
Collapse
|
36
|
Massaad C, Lombès M, Aggerbeck M, Rafestin-Oblin ME, Barouki R. Cell-specific, promoter-dependent mineralocorticoid agonist activity of spironolactone. Mol Pharmacol 1997; 51:285-92. [PMID: 9203634 DOI: 10.1124/mol.51.2.285] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The agonist activity of the antimineralocorticoid spironolactone was evaluated in various cell lines through the use of transfection experiments. The target promoters were derived from the deltaMTV promoter in which one or several glucocorticoid-responsive elements (GRE) were inserted in tandem. Spironolactone at 100 nM activated by 6-fold the GRE/deltaMTV promoter in the human hepatoma HepG2 cell line and only partially prevented the 10-fold activation of this promoter by 0.1 nM aldosterone. Both effects were completely dependent on the cotransfection of an expression vector for the mineralocorticoid receptor. The half-maximal agonist effect of spironolactone was similar to its half-maximal antagonist effect (approximately 10 nM). For the GRE-2/deltaMTV, GRE-4/deltaMTV, and wild-type MMTV promoters, the activation by aldosterone was much more potent (70-, 100-, and 110-fold, respectively), whereas spironolactone elicited a 10-, 24-, and 25-fold activation, respectively. Thus, the effect of both compounds and the relative efficiency of spironolactone, compared with that of aldosterone, were dependent on the number of GREs present in the regulatory region of the promoter. The agonist effect of spironolactone was cell specific. Indeed, although spironolactone agonist activity was observed in H5 kidney tubule cells, none could be detected at concentrations of < or = 1 microM in the CV1 monkey fibroblast cells. In contrast, the antagonist effect was observed in all cells. Furthermore, other antimineralocorticoids, such as RU 26752 and progesterone, also displayed mineralocorticoid receptor-dependent agonist activity in the HepG2 cells. The antiprogesterone RU 486 and the antiandrogen cyproterone acetate were ineffective at < or = 1 microM. In conclusion, we show that under certain experimental conditions, several antimineralocorticoids display significant agonist activity in a cell-specific and promoter-dependent manner.
Collapse
Affiliation(s)
- C Massaad
- Institute National de la Santé et de la Recherche Médicale Unité 99,Hôpital Henri Mondor, Créteil, France
| | | | | | | | | |
Collapse
|
37
|
Ankorina-Stark I, Haxelmans S, Schlatter E. Functional evidence for the regulation of cytosolic Ca2+ activity via V1A-receptors and beta-adrenoceptors in rat CCD. Cell Calcium 1997; 21:163-71. [PMID: 9132299 DOI: 10.1016/s0143-4160(97)90040-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In freshly isolated rat CCD segments, the effects of arginine vasopressin (AVP), oxytocin (OT), adrenaline (Ad), and their specific receptor agonists and antagonists on the intracellular Ca2+ activity ([Ca2+]i) were measured using the Ca2+ sensitive dye Fura-2 as fluorescence indicator. We observed that AVP, the V1-receptor agonist [Phe2Orn8] vasotocin ([Phe2]OVT), and OT increased [Ca2+]i biphasically. AVP (n = 9) and OT (n = 8) induced increases in [Ca2+]i were completely blocked by the V1A-receptor antagonist d(CH2)5Tyr(Me)2AVP. However, neither the V2-receptor agonist [Val4-D-Arg8]AVP (100 nM, n = 5), nor the OT-receptor agonist [Thr4,Gly7]OT (100 nM, n = 5) nor forskolin (1 microM, n = 4 and 10 microM, n = 5) did significantly change [Ca2+]i. Ad and the beta-adrenoceptor agonist isoproterenol (ISO) increased [Ca2+]i, which was not mimicked by the alpha 2-adrenoceptor agonist clonidine (1 microM, n = 10) or the alpha 1-adrenoceptor agonist phenylephrine (1 microM, n = 5). The beta-adrenoceptor antagonist propranolol (1 microM) completely blocked this Ad (1 microM, n = 4) induced [Ca2+]i increase. Insulin (INS 10 nM, n = 8), endothelin (ET 1 microM, n = 6), and angiotensin II (Ang II 1 pM to 10 nM; each n = 4) had no significant effect on [Ca2+]i. Considering the present results we propose a V1A-receptor and beta-adrenoceptor dependent modulation of [Ca2+]i in rat CCD.
Collapse
Affiliation(s)
- I Ankorina-Stark
- Medizinische Poliklinik, Westfälische Wilhelms-Universität, Münster, Germany
| | | | | |
Collapse
|
38
|
Millul V, Ardaillou N, Placier S, Baudouin B, Ronco PM. Receptors for natriuretic peptides in a human cortical collecting duct cell line. Kidney Int 1997; 51:281-7. [PMID: 8995744 DOI: 10.1038/ki.1997.34] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aim of the present study was to analyze the expression of natriuretic peptide receptors in human collecting duct, by using a newly established SV40 cell line (HCD). ANP and C-type natriuretic peptide (CNP) induced a concentration-dependent increase in cGMP suggesting the presence of type-A (NPR-A) and type-B (NPR-B) receptors, respectively. Threshold concentrations were 1 pM and 1 nM, respectively, and stimulated over basal cGMP ratios were 500 and 160 at 0.1 microM ANP and CNP. The urodilatin concentration-response curve was similar to that of ANP. [125I]-ANP bound specifically to HCD cells in a time-dependent fashion, reaching a plateau-phase between one and two hours at 4 degrees C. Equilibrium saturation binding curves suggested a single group of receptor sites (Kd = 421 +/- 55 pM, Bmax = 49.2 +/- 8.8 fmol/mg protein, Hill coefficient = 1.44 +/- 0.1, N = 6). Binding of [125I]-ANP was not displaced by CNP or by C-ANP (4-23), a specific ligand of clearance receptors (NPR-C), and thus occurred mainly via NPR-A. Neither Northern blot analysis nor RT-PCR could detect NPR-C mRNA, although the latter was clearly identified in control human glomerular visceral epithelial cells. In contrast, PCR products with the expected lengths were obtained for NPR-A and NPR-B. In conclusion, HCD cells express both NPR-A and NPR-B, as demonstrated by mRNA and cGMP production studies, but fail to produce NPR-C. This suggests that the human cortical collecting duct is a target for ANP, CNP and urodilatin.
Collapse
MESH Headings
- Atrial Natriuretic Factor/pharmacology
- Binding Sites/physiology
- Binding, Competitive/physiology
- Blotting, Northern
- Cell Line, Transformed/chemistry
- Cell Line, Transformed/metabolism
- Cyclic GMP/metabolism
- Humans
- Iodine Radioisotopes
- Kidney Cortex/cytology
- Kidney Cortex/ultrastructure
- Kidney Tubules, Collecting/chemistry
- Kidney Tubules, Collecting/cytology
- Polymerase Chain Reaction
- RNA, Messenger/analysis
- Receptors, Atrial Natriuretic Factor/analysis
- Receptors, Atrial Natriuretic Factor/chemistry
- Receptors, Atrial Natriuretic Factor/genetics
- Transcription, Genetic/physiology
Collapse
Affiliation(s)
- V Millul
- INSERM U64, Hôpital Tenon, Paris, France
| | | | | | | | | |
Collapse
|
39
|
Thomas CP, Doggett NA, Fisher R, Stokes JB. Genomic organization and the 5' flanking region of the gamma subunit of the human amiloride-sensitive epithelial sodium channel. J Biol Chem 1996; 271:26062-6. [PMID: 8824247 DOI: 10.1074/jbc.271.42.26062] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The amiloride-sensitive epithelial sodium channel (ENaC) complex is made up of at least three different subunits alpha, beta, and gamma, which are developmentally regulated, selectively expressed, and variously up-regulated by steroid hormones. To understand mechanisms involved in regulation of the gamma subunit, we have determined the structure of the human gammaENaC gene. By 5' rapid amplification of cDNA ends, primer extension analysis, and nuclease protection assay, we identified transcription start sites in human brain, kidney, and lung. A human genomic library was screened and overlapping cosmid clones that span approximately 50 kilobases and contain the hgammaENaC gene were identified. The 5'-untranslated region is 141 bases long, and the translation start codon is contained within the second exon. The human gene spans at least 35 kilobases. The 5' end of the gene including portions of 5' flanking genomic DNA and the first intron are G + C rich and contain several CpG dinucleotides, consistent with a CpG island. The 5' flanking region contains no CCAAT or TATA-like elements but does contain two GC boxes as well as several putative transcription factor binding sites including AP-2, Sp1, CRE, PEA-3, and NF-IL6. This is the first description of the structural organization and the 5' flanking region of a member of the epithelial sodium channel complex.
Collapse
Affiliation(s)
- C P Thomas
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA 52242-1081, USA
| | | | | | | |
Collapse
|
40
|
Valenti G, Frigeri A, Ronco PM, D'Ettorre C, Svelto M. Expression and functional analysis of water channels in a stably AQP2-transfected human collecting duct cell line. J Biol Chem 1996; 271:24365-70. [PMID: 8798691 DOI: 10.1074/jbc.271.40.24365] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In this study, we describe the establishment of a stably transfected epithelial cell line with the cDNA for the rat aquaporin 2 (AQP2). To this end, we used a human cell line (HCD) derived from the cortical collecting duct and having characteristics of principal cells (Prié, D., Friedlander, G., Coureau, C., Vandewalle, A., Cassigena, R., and Ronco, P. M. (1995) Kidney Int. 47, 1310-1318). The HCD cells were first screened for the constitutive expression of AQPs. By Western blot analysis, we found a low expression of immunoreactive AQP2 and AQP4 proteins. In contrast, transfected cells (clone CD8) probed with AQP2 antiserum expressed an intense 29-kDa protein on immunoblot in addition to a broad band between 35-45 kDa corresponding to the glycosylated form of the protein, indicating that full maturity of the protein is attained in transfected cells. Immunofluorescence demonstrated that AQP2 was located in intracellular vesicles. After vasopressin stimulation, the staining redistributed from an intracellular site to the apical pole of the cells, an effect similar to that described on collecting duct principal cells in vivo (Sabolic, I., Katsura, T., Verbavatz, J. M., and Brown, D. (1995) J. Membr. Biol. 143, 165-175) and in perfused tubules (Nielsen, S., Chou, C. L., Marples, D., Christensen, E. I., Kishore, B. K., and Knepper, M. A. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 1013-1017). The redistribution of AQP2 in CD8 cells was accompanied by an approximately 6-fold increase in osmotic water permeability coefficient (Pf), which was inhibited by 0.3 m HgCl2. These data indicate that functional vasopressin-sensitive water channels are expressed in transfected cells. The stably transfected cells represent a suitable model to unravel by direct experimental approach the intracellular signals involved in the translocation of AQP2 to the apical plasma membrane in the presence of vasopressin.
Collapse
Affiliation(s)
- G Valenti
- Istituto di Fisiologia Generale, Università degli Studi di Bari, Via Amendola 165/A, 70126 Bari, Italy
| | | | | | | | | |
Collapse
|
41
|
Czekalski S, Chansel D, Vandermeersch S, Ronco P, Ardaillou R. Evidence for angiotensin IV receptors in human collecting duct cells. Kidney Int 1996; 50:1125-31. [PMID: 8887269 DOI: 10.1038/ki.1996.419] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Because angiotensin II (Ang II) has been found at high concentrations in the proximal tubule fluid and because tubular brush border membranes exhibit a marked capacity for degrading Ang II, we thought it of interest to examine the binding sites for Ang II (3-8) (referred to as Ang IV), a metabolite of Ang II, downstream in the nephron. We studied the binding of [125I]-Ang IV and also of [125I]-Sar1, Ala8, Ang II to SV-40 transformed human collecting duct cell (HCD) membranes. No specific binding site for [125I]-Sar1, Ala8, Ang II and no Ang II-dependent cytosolic calcium response could be observed. Moreover, no signal for the human type I Ang II receptor (hAT1) mRNA was present in HCD cells. In contrast, [125I]-Ang IV bound specifically to HCD cell membranes. Mean Kd and Bmax values derived from saturation binding studies were 5.6 +/- 2.0 nM and 1007.6 +/- 140.2 fmol/mg protein, respectively. The rank order of affinity for competitive Ang II-related peptides was: Ang IV > Ang III > Ang II > Ang II (4-8) > Ang II (1-7). [125I]-Ang IV binding was not modified by nonpeptide AT1 (losartan) or AT2 (PD123177) antagonists. GTP gamma S and dithiotreitol did not affect [125I]-Ang IV binding. Ang IV stimulated cAMP production by intact HCD cells in the presence of forskolin but did not modify cGMP production or cytosolic calcium concentration. Taken together, these results indicate that HCD cells represent a target site for Ang IV but do not possess Ang II receptors.
Collapse
|
42
|
Kruidering M, van de Water B, Nagelkerke JF. Methods for studying renal toxicity. ARCHIVES OF TOXICOLOGY. SUPPLEMENT. = ARCHIV FUR TOXIKOLOGIE. SUPPLEMENT 1996; 18:173-83. [PMID: 8678793 DOI: 10.1007/978-3-642-61105-6_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- M Kruidering
- Leiden Amsterdam Center for Drug Research, Sylvius Laboratories, University of Leiden, The Netherlands
| | | | | |
Collapse
|