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Yanda MK, Ciobanu C, Guggino WB, Cebotaru L. CFTR and PC2, partners in the primary cilia in autosomal dominant polycystic kidney disease. Am J Physiol Cell Physiol 2023; 325:C682-C693. [PMID: 37519231 PMCID: PMC10635646 DOI: 10.1152/ajpcell.00197.2023] [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: 05/09/2023] [Revised: 07/13/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
Defects in the primary cilium are associated with autosomal dominant polycystic kidney disease (ADPKD). We used a combination of animal models, Western blotting, and confocal microscopy and discovered that CFTR and polycystin 2 (PC2) are both colocalized to the cilium in normal kidneys, with the levels of both being decreased in cystic epithelia. Cilia were longer in CFTR-null mice and in cystic cells in our ADPKD animal models. We examined septin 2, known to play a role in cilia length, to act as a diffusion barrier and to serve as an enhancer of proliferation. We found that septin 2 protein levels were upregulated and colocalized strongly with CFTR in cystic cells. Application of VX-809, the CFTR corrector, restored CFTR and PC2 toward normal in the cilia, decreased the protein levels of septin 2, and drastically reduced septin 2 colocalization with CFTR. Our data suggest that CFTR is present in the cilia and plays a role there, perhaps through its conductance of Cl-. We also postulate that septin 2 is important for localizing CFTR to the apical membrane in cystic epithelia.NEW & NOTEWORTHY CFTR is present in the primary cilia together with polycystin 2 (PC2). Ablation of CFTR makes cilia longer suggesting that CFTR plays a role there, perhaps through its conductance of Cl.
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Affiliation(s)
- Murali K Yanda
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Cristian Ciobanu
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - William B Guggino
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liudmila Cebotaru
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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2
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Kunzelmann K, Ousingsawat J, Kraus A, Park JH, Marquardt T, Schreiber R, Buchholz B. Pathogenic Relationships in Cystic Fibrosis and Renal Diseases: CFTR, SLC26A9 and Anoctamins. Int J Mol Sci 2023; 24:13278. [PMID: 37686084 PMCID: PMC10487509 DOI: 10.3390/ijms241713278] [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: 06/28/2023] [Revised: 07/31/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
The Cl--transporting proteins CFTR, SLC26A9, and anoctamin (ANO1; ANO6) appear to have more in common than initially suspected, as they all participate in the pathogenic process and clinical outcomes of airway and renal diseases. In the present review, we will therefore concentrate on recent findings concerning electrolyte transport in the airways and kidneys, and the role of CFTR, SLC26A9, and the anoctamins ANO1 and ANO6. Special emphasis will be placed on cystic fibrosis and asthma, as well as renal alkalosis and polycystic kidney disease. In essence, we will summarize recent evidence indicating that CFTR is the only relevant secretory Cl- channel in airways under basal (nonstimulated) conditions and after stimulation by secretagogues. Information is provided on the expressions of ANO1 and ANO6, which are important for the correct expression and function of CFTR. In addition, there is evidence that the Cl- transporter SLC26A9 expressed in the airways may have a reabsorptive rather than a Cl--secretory function. In the renal collecting ducts, bicarbonate secretion occurs through a synergistic action of CFTR and the Cl-/HCO3- transporter SLC26A4 (pendrin), which is probably supported by ANO1. Finally, in autosomal dominant polycystic kidney disease (ADPKD), the secretory function of CFTR in renal cyst formation may have been overestimated, whereas ANO1 and ANO6 have now been shown to be crucial in ADPKD and therefore represent new pharmacological targets for the treatment of polycystic kidney disease.
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Affiliation(s)
- Karl Kunzelmann
- Physiological Institute, University of Regensburg, University Street 31, 93053 Regensburg, Germany; (J.O.); (R.S.)
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University Street 31, 93053 Regensburg, Germany; (J.O.); (R.S.)
| | - Andre Kraus
- Department of Nephrology and Hypertension, Friedrich Alexander University Erlangen Nuremberg, 91054 Erlangen, Germany; (A.K.); (B.B.)
| | - Julien H. Park
- Department of Pediatrics, University Hospital Münster, 48149 Münster, Germany; (J.H.P.); (T.M.)
| | - Thorsten Marquardt
- Department of Pediatrics, University Hospital Münster, 48149 Münster, Germany; (J.H.P.); (T.M.)
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, University Street 31, 93053 Regensburg, Germany; (J.O.); (R.S.)
| | - Björn Buchholz
- Department of Nephrology and Hypertension, Friedrich Alexander University Erlangen Nuremberg, 91054 Erlangen, Germany; (A.K.); (B.B.)
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Yanda MK, Zeidan A, Cebotaru L. Ameliorating liver disease in an autosomal recessive polycystic kidney disease mouse model. Am J Physiol Gastrointest Liver Physiol 2023; 324:G404-G414. [PMID: 36880660 PMCID: PMC10085553 DOI: 10.1152/ajpgi.00255.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023]
Abstract
Systemic and portal hypertension, liver fibrosis, and hepatomegaly are manifestations associated with autosomal recessive polycystic kidney disease (ARPKD), which is caused by malfunctions of fibrocystin/polyductin (FPC). The goal is to understand how liver pathology occurs and to devise therapeutic strategies to treat it. We injected 5-day-old Pkhd1del3-4/del3-4 mice for 1 mo with the cystic fibrosis transmembrane conductance regulator (CFTR) modulator VX-809 designed to rescue processing and trafficking of CFTR folding mutants. We used immunostaining and immunofluorescence techniques to evaluate liver pathology. We assessed protein expression via Western blotting. We detected abnormal biliary ducts consistent with ductal plate abnormalities, as well as a greatly increased proliferation of cholangiocytes in the Pkhd1del3-4/del3-4 mice. CFTR was present in the apical membrane of cholangiocytes and increased in the Pkhd1del3-4/del3-4 mice, consistent with a role for apically located CFTR in enlarged bile ducts. Interestingly, we also found CFTR in the primary cilium, in association with polycystin (PC2). Localization of CFTR and PC2 and overall length of the cilia were increased in the Pkhd1del3-4/del3-4 mice. In addition, several of the heat shock proteins; 27, 70, and 90 were upregulated, suggesting that global changes in protein processing and trafficking had occurred. We found that a deficit of FPC leads to bile duct abnormalities, enhanced cholangiocyte proliferation, and misregulation of heat shock proteins, which all returned toward wild type (WT) values following VX-809 treatment. These data suggest that CFTR correctors can be useful as therapeutics for ARPKD. Given that these drugs are already approved for use in humans, they can be fast-tracked for clinical use.NEW & NOTEWORTHY ARPKD is a multiorgan genetic disorder resulting in newborn morbidity and mortality. There is a critical need for new therapies to treat this disease. We show that persistent cholangiocytes proliferation occurs in a mouse model of ARPKD along with mislocalized CFTR and misregulated heat shock proteins. We found that VX-809, a CFTR modulator, inhibits proliferation and limits bile duct malformation. The data provide a therapeutic pathway for strategies to treat ADPKD.
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Affiliation(s)
- Murali K Yanda
- Departments of Medicine and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Adi Zeidan
- Departments of Medicine and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liudmila Cebotaru
- Departments of Medicine and Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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Zhou JX, Torres VE. Autosomal Dominant Polycystic Kidney Disease Therapies on the Horizon. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:245-260. [PMID: 37088527 DOI: 10.1053/j.akdh.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/21/2022] [Accepted: 01/06/2023] [Indexed: 04/25/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation of numerous kidney cysts which leads to kidney failure. ADPKD is responsible for approximately 10% of patients with kidney failure. Overwhelming evidence supports that vasopressin and its downstream cyclic adenosine monophosphate signaling promote cystogenesis, and targeting vasopressin 2 receptor with tolvaptan and other antagonists ameliorates cyst growth in preclinical studies. Tolvaptan is the only drug approved by Food and Drug Administration to treat ADPKD patients at the risk of rapid disease progression. A major limitation of the widespread use of tolvaptan is aquaretic events. This review discusses the potential strategies to improve the tolerability of tolvaptan, the progress on the use of an alternative vasopressin 2 receptor antagonist lixivaptan, and somatostatin analogs. Recent advances in understanding the pathophysiology of PKD have led to new approaches of treatment via targeting different signaling pathways. We review the new pharmacotherapies and dietary interventions of ADPKD that are promising in the preclinical studies and investigated in clinical trials.
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Devlin L, Dhondurao Sudhindar P, Sayer JA. Renal ciliopathies: promising drug targets and prospects for clinical trials. Expert Opin Ther Targets 2023; 27:325-346. [PMID: 37243567 DOI: 10.1080/14728222.2023.2218616] [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: 03/06/2023] [Revised: 05/12/2023] [Accepted: 05/23/2023] [Indexed: 05/29/2023]
Abstract
INTRODUCTION Renal ciliopathies represent a collection of genetic disorders characterized by deficiencies in the biogenesis, maintenance, or functioning of the ciliary complex. These disorders, which encompass autosomal dominant polycystic kidney disease (ADPKD), autosomal recessive polycystic kidney disease (ARPKD), and nephronophthisis (NPHP), typically result in cystic kidney disease, renal fibrosis, and a gradual deterioration of kidney function, culminating in kidney failure. AREAS COVERED Here we review the advances in basic science and clinical research into renal ciliopathies which have yielded promising small compounds and drug targets, within both preclinical studies and clinical trials. EXPERT OPINION Tolvaptan is currently the sole approved treatment option available for ADPKD patients, while no approved treatment alternatives exist for ARPKD or NPHP patients. Clinical trials are presently underway to evaluate additional medications in ADPKD and ARPKD patients. Based on preclinical models, other potential therapeutic targets for ADPKD, ARPKD, and NPHP look promising. These include molecules targeting fluid transport, cellular metabolism, ciliary signaling and cell-cycle regulation. There is a real and urgent clinical need for translational research to bring novel treatments to clinical use for all forms of renal ciliopathies to reduce kidney disease progression and prevent kidney failure.
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Affiliation(s)
- Laura Devlin
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Praveen Dhondurao Sudhindar
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - John A Sayer
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, UK
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle Upon Tyne, UK
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Zhou JX, Torres VE. Drug repurposing in autosomal dominant polycystic kidney disease. Kidney Int 2023; 103:859-871. [PMID: 36870435 DOI: 10.1016/j.kint.2023.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/23/2023] [Accepted: 02/07/2023] [Indexed: 03/06/2023]
Abstract
Autosomal dominant polycystic kidney disease is characterized by progressive kidney cyst formation that leads to kidney failure. Tolvaptan, a vasopressin 2 receptor antagonist, is the only drug approved to treat patients with autosomal dominant polycystic kidney disease who have rapid disease progression. The use of tolvaptan is limited by reduced tolerability from aquaretic effects and potential hepatotoxicity. Thus, the search for more effective drugs to slow down the progression of autosomal dominant polycystic kidney disease is urgent and challenging. Drug repurposing is a strategy for identifying new clinical indications for approved or investigational medications. Drug repurposing is increasingly becoming an attractive proposition because of its cost-efficiency and time-efficiency and known pharmacokinetic and safety profiles. In this review, we focus on the repurposing approaches to identify suitable drug candidates to treat autosomal dominant polycystic kidney disease and prioritization and implementation of candidates with high probability of success. Identification of drug candidates through understanding of disease pathogenesis and signaling pathways is highlighted.
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Affiliation(s)
- Julie Xia Zhou
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA; Mayo Clinic Robert M. and Billie Kelley Pirnie Translational Polycystic Kidney Disease Center, Rochester, Minnesota, USA.
| | - Vicente E Torres
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA; Mayo Clinic Robert M. and Billie Kelley Pirnie Translational Polycystic Kidney Disease Center, Rochester, Minnesota, USA.
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Bais T, Gansevoort RT, Meijer E. Drugs in Clinical Development to Treat Autosomal Dominant Polycystic Kidney Disease. Drugs 2022; 82:1095-1115. [PMID: 35852784 PMCID: PMC9329410 DOI: 10.1007/s40265-022-01745-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2022] [Indexed: 12/16/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cyst formation that ultimately leads to kidney failure in most patients. Approximately 10% of patients who receive kidney replacement therapy suffer from ADPKD. To date, a vasopressin V2 receptor antagonist (V2RA) is the only drug that has been proven to attenuate disease progression. However, aquaresis-related adverse events limit its widespread use. Data on the renoprotective effects of somatostatin analogues differ largely between studies and medications. This review discusses new drugs that are investigated in clinical trials to treat ADPKD, such as cystic fibrosis transmembrane conductance regulator (CFTR) modulators and micro RNA inhibitors, and drugs already marketed for other indications that are being investigated for off-label use in ADPKD, such as metformin. In addition, potential methods to improve the tolerability of V2RAs are discussed, as well as methods to select patients with (likely) rapid disease progression and issues regarding the translation of preclinical data into clinical practice. Since ADPKD is a complex disease with a high degree of interindividual heterogeneity, and the mechanisms involved in cyst growth also have important functions in various physiological processes, it may prove difficult to develop drugs that target cyst growth without causing major adverse events. This is especially important since long-standing treatment is necessary in this chronic disease. This review therefore also discusses approaches to targeted therapy to minimize systemic side effects. Hopefully, these developments will advance the treatment of ADPKD.
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Yanda MK, Tomar V, Cole R, Guggino WB, Cebotaru L. The Mitochondrial Ca 2+ import complex is altered in ADPKD. Cell Calcium 2022; 101:102501. [PMID: 34823104 PMCID: PMC8840832 DOI: 10.1016/j.ceca.2021.102501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/05/2021] [Accepted: 11/06/2021] [Indexed: 01/03/2023]
Abstract
Mutations in either of the polycystic kidney disease genes, PKD1 or PKD2, engender the growth of cysts, altering renal function. Cystic growth is supported by major changes in cellular metabolism, some of which involve the mitochondrion, a major storage site for Ca2+ and a key organelle in cellular Ca2+ signaling. The goal here was to understand the role of components of the mitochondrial Ca2+ uptake complex in PC1-mutant cells in autosomal dominant polycystic kidney disease (ADPKD). We found that the mitochondrial Ca2+ uniporter (MCU) and voltage-dependent anion channels 1& 3 (VDAC) were down-regulated in different mouse and cell models of ADPKD along with the Ca2+-dependent enzyme, pyruvate dehydrogenase phosphatase (PDHX). The release of Ca2+ from the endoplasmic reticulum, and Ca2+ uptake by the mitochondria were upregulated in PC1(polycystin)-null cells. We also observed an enhanced staining with MitoTracker Red CMXRos in PC1-null cultured cells than in PC1-containing cells and a substantially higher increase in response to ER Ca2+ release. Increased colocalization of the Ca2+ sensitive dye, rhodamine2, with MitoTracker Green suggested an increase Ca2+ entry into the mitochondria in PC1 null cells subsequent to Ca2+ release from the ER or from Ca2+ entry from the extracellular solution. These data clearly demonstrate abnormal release of Ca2+ by the ER and corresponding alterations in Ca2+ uptake by the mitochondria in PC1-null cells. Importantly, inhibiting mitochondrial Ca2+ uptake with the specific inhibitor Ru360 inhibited cyst growth and altered both apoptosis and cell proliferation. We further show that the decrease in mitochondrial proteins and abnormally high Ca2+ signaling can be reversed by application of the cystic fibrosis (CFTR) corrector, VX-809. We conclude that enhanced Ca2+ signaling and alterations in proteins association with the mitochondrial Ca2+ uptake complex are associated with malfunction of PC1. Finally, our results identify novel therapeutic targets for treating ADPKD.
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Affiliation(s)
- Murali K Yanda
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Vartika Tomar
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Robert Cole
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - William B Guggino
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Liudmila Cebotaru
- The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
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Sudarikova A, Vasileva V, Sultanova R, Ilatovskaya D. Recent advances in understanding ion transport mechanisms in polycystic kidney disease. Clin Sci (Lond) 2021; 135:2521-2540. [PMID: 34751394 PMCID: PMC8589009 DOI: 10.1042/cs20210370] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 10/15/2021] [Accepted: 10/26/2021] [Indexed: 12/18/2022]
Abstract
This review focuses on the most recent advances in the understanding of the electrolyte transport-related mechanisms important for the development of severe inherited renal disorders, autosomal dominant (AD) and recessive (AR) forms of polycystic kidney disease (PKD). We provide here a basic overview of the origins and clinical aspects of ARPKD and ADPKD and discuss the implications of electrolyte transport in cystogenesis. Special attention is devoted to intracellular calcium handling by the cystic cells, with a focus on polycystins and fibrocystin, as well as other calcium level regulators, such as transient receptor potential vanilloid type 4 (TRPV4) channels, ciliary machinery, and purinergic receptor remodeling. Sodium transport is reviewed with a focus on the epithelial sodium channel (ENaC), and the role of chloride-dependent fluid secretion in cystic fluid accumulation is discussed. In addition, we highlight the emerging promising concepts in the field, such as potassium transport, and suggest some new avenues for research related to electrolyte handling.
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Affiliation(s)
| | | | - Regina F. Sultanova
- Saint-Petersburg State Chemical Pharmaceutical University, St. Petersburg, Russia
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Olesen ETB, Fenton RA. Aquaporin 2 regulation: implications for water balance and polycystic kidney diseases. Nat Rev Nephrol 2021; 17:765-781. [PMID: 34211154 DOI: 10.1038/s41581-021-00447-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2021] [Indexed: 02/06/2023]
Abstract
Targeting the collecting duct water channel aquaporin 2 (AQP2) to the plasma membrane is essential for the maintenance of mammalian water homeostasis. The vasopressin V2 receptor (V2R), which is a GS protein-coupled receptor that increases intracellular cAMP levels, has a major role in this targeting process. Although a rise in cAMP levels and activation of protein kinase A are involved in facilitating the actions of V2R, studies in knockout mice and cell models have suggested that cAMP signalling pathways are not an absolute requirement for V2R-mediated AQP2 trafficking to the plasma membrane. In addition, although AQP2 phosphorylation is a known prerequisite for V2R-mediated plasma membrane targeting, none of the known AQP2 phosphorylation events appears to be rate-limiting in this process, which suggests the involvement of other factors; cytoskeletal remodelling has also been implicated. Notably, several regulatory processes and signalling pathways involved in AQP2 trafficking also have a role in the pathophysiology of autosomal dominant polycystic kidney disease, although the role of AQP2 in cyst progression is unknown. Here, we highlight advances in the field of AQP2 regulation that might be exploited for the treatment of water balance disorders and provide a rationale for targeting these pathways in autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Emma T B Olesen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Endocrinology and Nephrology, North Zealand Hospital, Hillerød, Denmark.
| | - Robert A Fenton
- Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus, Denmark.
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Yanda MK, Cebotaru L. VX-809 mitigates disease in a mouse model of autosomal dominant polycystic kidney disease bearing the R3277C human mutation. FASEB J 2021; 35:e21987. [PMID: 34662459 DOI: 10.1096/fj.202101315r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/20/2021] [Accepted: 09/28/2021] [Indexed: 12/11/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is associated with the formation of renal cysts. We have devised a therapeutic approach, based on reversing the cyst phenotype from secretion to absorption by using VX-809, a modulator of the cystic fibrosis transmembrane regulator trafficking and processing. Our goal is to test VX-809 in RC/RC mice bearing the R3277C human mutation to demonstrate its therapeutic potential. We found that by 5 months of age, RC/RC mice had large cysts and impaired renal function, but when treated with VX-809 between the ages of 3 and 5 months, or 6 and 8 months, the cyst area was reduced in both groups, suggesting that VX-809 had shrunk previously existing cysts. After 2 months of treatment, the cyst size was lower than that of untreated animals of the same age. Our co-localization studies confirmed that cystic fibrosis transmembrane conductance regulator (CFTR) is found predominately at the apical membrane in the untreated animals of each age group, consistent with its role in Cl- secretion; after VX-809 treatment, the basolateral membrane co-localization of CFTR increased ~4-fold, accompanied by a decrease of ~2-3-fold in its apical co-localization, indicating that VX-809 alters the phenotype to favor fluid absorption. Sodium/hydrogen exchanger and epithelial sodium channel, found in normal kidneys at the apical membrane, were almost absent from the cysts. VX-809 restored both levels toward normal. HSP27 is highly expressed in RC/RC mice and lowered toward normal by VX-809. Our demonstration of cyst reduction, improved renal function, and generation of an absorptive phenotype all strongly support the therapeutic potential of VX-809 as a treatment for ADPKD. We show here in an animal model of slowly progressing cyst formation typical of human ADPKD that VX-809 reduces the growth of already established cysts. The magnitude of the effect in the RC/RC mouse model when compared to previous experiments using the same mouse model to evaluate tolvaptan indicates that CFTR modulators warrant further development as a treatment for ADPKD.
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Affiliation(s)
- Murali K Yanda
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Liudmila Cebotaru
- Division of Gastroenterology and Hepatology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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12
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Talbi K, Cabrita I, Kraus A, Hofmann S, Skoczynski K, Kunzelmann K, Buchholz B, Schreiber R. The chloride channel CFTR is not required for cyst growth in an ADPKD mouse model. FASEB J 2021; 35:e21897. [PMID: 34473378 DOI: 10.1096/fj.202100843r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/09/2021] [Accepted: 08/18/2021] [Indexed: 01/01/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development of bilateral renal cysts which enlarge continuously, leading to compression of adjacent intact nephrons. The growing cysts lead to a progressive decline in renal function. Cyst growth is driven by enhanced cell proliferation and chloride secretion into the cyst lumen. Chloride secretion is believed to occur mainly by the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR), with some contribution by the calcium-activated chloride channel TMEM16A. However, our previous work suggested TMEM16A as a major factor for renal cyst formation. The contribution of CFTR to cyst formation has never been demonstrated in an adult ADPKD mouse model. We used mice with an inducible tubule-specific Pkd1 knockout, which consistently develop polycystic kidneys upon deletion of Pkd1. Cellular properties, ion currents, and cyst development in these mice were compared with that of mice carrying a co-deletion of Pkd1 and Cftr. Knockout of Cftr did not reveal any significant impact on cyst formation in the ADPKD mouse model. Furthermore, knockout of Cftr did not attenuate the largely augmented cell proliferation observed in Pkd1 knockout kidneys. Patch clamp analysis on primary renal epithelial cells lacking expression of Pkd1 indicated an only marginal contribution of CFTR to whole cell Cl- currents, which were clearly dominated by calcium-activated TMEM16A currents. In conclusion, CFTR does not essentially contribute to renal cyst formation in mice caused by deletion of Pkd1. Enhanced cell proliferation and chloride secretion is caused primarily by upregulation of the calcium-activated chloride channel TMEM16A.
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Affiliation(s)
- Khaoula Talbi
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Inês Cabrita
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Andre Kraus
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Sascha Hofmann
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Kathrin Skoczynski
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, Regensburg, Germany
| | - Bjoern Buchholz
- Department of Nephrology and Hypertension, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Rainer Schreiber
- Department of Physiology, University of Regensburg, Regensburg, Germany
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13
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Therapeutic Potential for CFTR Correctors in Autosomal Recessive Polycystic Kidney Disease. Cell Mol Gastroenterol Hepatol 2021; 12:1517-1529. [PMID: 34329764 PMCID: PMC8529398 DOI: 10.1016/j.jcmgh.2021.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Autosomal recessive polycystic kidney disease (ARPKD) is caused by mutations in PKHD1, encoding fibrocystin/polyductin (FPC). Severe disease occurs in perinates. Those who survive the neonatal period face a myriad of comorbidities, including systemic and portal hypertension, liver fibrosis, and hepatosplenomegaly. The goal here was to uncover therapeutic strategies for ARPKD. METHODS We used wild-type and an FPC-mutant cholangiocyte cell line in 3-dimenional cysts and in confluent monolayers to evaluate protein expression using western blotting and protein trafficking using confocal microscopy. RESULTS We found that the protein level of the cystic fibrosis transmembrane conductance regulator (CFTR) was downregulated. The levels of heat shock proteins (HSPs) were altered in the FPC-mutant cholangiocytes, with HSP27 being downregulated and HSP90 and HSP70 upregulated. FPC-mutant cholangiocytes formed cysts, but normal cells did not. Cyst growth could be reduced by increasing HSP27 protein levels, by HSP90 and HSP70 inhibitor treatments, by silencing HSP90 through messenger RNA inhibition, or by the novel approach of treating the cysts with the CFTR corrector VX-809. In wild-type cholangiocytes, CFTR is present in both apical and basolateral membranes. FPC malfunction resulted in altered colocalization of CFTR with both apical and basolateral membranes. Whereas, treatment with VX-809, increasing HSP27 or inhibiting HSP70 or HSP90 restored CFTR localization toward normal values. CONCLUSIONS FPC malfunction induces the formation of cysts, which are fueled by alterations in HSPs and in CFTR protein levels and miss-localization. We suggest that CFTR correctors, already in clinical use to treat cystic fibrosis, could also be used as a treatment for ARPKD.
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Duong Phu M, Bross S, Burkhalter MD, Philipp M. Limitations and opportunities in the pharmacotherapy of ciliopathies. Pharmacol Ther 2021; 225:107841. [PMID: 33771583 DOI: 10.1016/j.pharmthera.2021.107841] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/11/2021] [Indexed: 01/10/2023]
Abstract
Ciliopathies are a family of rather diverse conditions, which have been grouped based on the finding of altered or dysfunctional cilia, potentially motile, small cellular antennae extending from the surface of postmitotic cells. Cilia-related disorders include embryonically arising conditions such as Joubert, Usher or Kartagener syndrome, but also afflictions with a postnatal or even adult onset phenotype, i.e. autosomal dominant polycystic kidney disease. The majority of ciliopathies are syndromic rather than affecting only a single organ due to cilia being found on almost any cell in the human body. Overall ciliopathies are considered rare diseases. Despite that, pharmacological research and the strive to help these patients has led to enormous therapeutic advances in the last decade. In this review we discuss new treatment options for certain ciliopathies, give an outlook on promising future therapeutic strategies, but also highlight the limitations in the development of therapeutic approaches of ciliopathies.
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Affiliation(s)
- Max Duong Phu
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Stefan Bross
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Martin D Burkhalter
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany
| | - Melanie Philipp
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Section of Pharmacogenomics, Eberhard-Karls-University of Tübingen, 72074 Tübingen, Germany.
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K. Rangan G, Raghubanshi A, Chaitarvornkit A, Chandra AN, Gardos R, Munt A, Read MN, Saravanabavan S, Zhang JQ, Wong AT. Current and emerging treatment options to prevent renal failure due to autosomal dominant polycystic kidney disease. Expert Opin Orphan Drugs 2020. [DOI: 10.1080/21678707.2020.1804859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Gopala K. Rangan
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
- Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Westmead, Australia
| | - Aarya Raghubanshi
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
| | - Alissa Chaitarvornkit
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
- Faculty of Engineering, The University of Sydney, Camperdown, Australia
| | - Ashley N. Chandra
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
| | | | - Alexandra Munt
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
- Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Westmead, Australia
| | - Mark N. Read
- The School of Computer Science and the Westmead Initiative, The University of Sydney, Westmead, Australia
| | - Sayanthooran Saravanabavan
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
| | - Jennifer Q.J. Zhang
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
| | - Annette T.Y. Wong
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Westmead, Australia
- Department of Renal Medicine, Westmead Hospital, Western Sydney Local Health District, Westmead, Australia
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Jouret F, Devuyst O. Targeting chloride transport in autosomal dominant polycystic kidney disease. Cell Signal 2020; 73:109703. [PMID: 32619563 DOI: 10.1016/j.cellsig.2020.109703] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent inherited kidney disease. Transepithelial fluid secretion is one of the key factors of cystogenesis in ADPKD. Multiple studies have suggested that fluid secretion across ADPKD cyst-lining cells is driven by the secretion of chloride, essentially mediated by the CFTR channel and stimulated by increased intracellular levels of 3',5'-cyclic adenosine monophosphate. This review focuses on the pathophysiology of fluid secretion in ADPKD based on the pioneering studies of Jared Grantham and colleagues, and on the follow-up investigations from the molecular level to the potential applications in ADPKD patients. Altogether, the studies of fluid and chloride transport in ADPKD paved the way for innovative therapeutic targets to prevent cyst volume expansion and thus, kidney disease progression.
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Affiliation(s)
- François Jouret
- Division of Nephrology, Department of Internal Medicine, ULiège Academic Hospital, Liège, Belgium,; Groupe Interdisciplinaire de Géno-protéomique Appliquée, Cardiovascular Sciences, ULiège Medical School, Liège, Belgium
| | - Olivier Devuyst
- Division of Nephrology, UCLouvain Medical School, B-1200, Brussels, Belgium,; Mechanisms of Inherited Kidney Disorders, University of Zurich, CH-8057 Zurich, Switzerland.
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