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Cuffe JSM, Briffa JF, Rosser S, Siebel AL, Romano T, Hryciw DH, Wlodek ME, Moritz KM. Uteroplacental insufficiency in rats induces renal apoptosis and delays nephrogenesis completion. Acta Physiol (Oxf) 2018; 222. [PMID: 29047216 DOI: 10.1111/apha.12982] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 10/08/2017] [Accepted: 10/10/2017] [Indexed: 12/28/2022]
Abstract
AIM Uteroplacental insufficiency in rats reduces nephron endowment, leptin concentrations and programmes cardiorenal disease in offspring. Cross-fostering growth-restricted (Restricted) offspring onto a mother with normal lactation restores leptin concentrations and nephron endowment. This study aimed to determine whether the reduced nephron endowment in Restricted offspring is due to delayed glomerular formation and dysregulation of renal genes regulating branching morphogenesis, apoptosis or leptin signalling. Furthermore, we aimed to investigate whether cross-fostering Restricted offspring onto Control mothers could improve glomerular maturation and restore renal gene abundance. METHODS Uteroplacental insufficiency was induced by bilateral uterine vessel ligation (Restricted) or sham (Control) surgery on gestation day 18 (E18). Kidneys were collected at E20, postnatal day 1 (PN1) and PN7. An additional cohort was cross-fostered onto separate mothers at birth and kidneys collected at PN7. RESULTS Kidneys were lighter in the Restricted group, but weight was restored with cross-fostering. At E20, abundance of Bax, Flt1 and Vegfa was increased in Restricted offspring, while Ret and Bcl2 transcripts were increased only in Restricted females. At PN7, abundance of Gdnf and Ret was higher in Restricted offspring, as was Casp3. Restricted offspring had a wider nephrogenic zone with more immature glomeruli suggesting a delayed or extended nephrogenic period. Cross-fostering had subtle effects on gene abundance and glomerular maturity. CONCLUSION Uteroplacental insufficiency induced apoptosis in the developing kidney and delayed and extended nephrogenesis. Cross-fostering Restricted offspring onto Control mothers had beneficial effects on kidney growth and renal maturity, which may contribute to the restoration of nephron endowment.
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Affiliation(s)
- J. S. M. Cuffe
- School of Biomedical Sciences; The University of Queensland; St. Lucia Qld Australia
- School of Medical Science; Menzies Health Institute Queensland; Griffith University; Southport Qld Australia
| | - J. F. Briffa
- Department of Physiology; The University of Melbourne; Parkville Vic. Australia
| | - S. Rosser
- School of Biomedical Sciences; The University of Queensland; St. Lucia Qld Australia
| | - A. L. Siebel
- Department of Physiology; The University of Melbourne; Parkville Vic. Australia
| | - T. Romano
- Department of Physiology, Anatomy and Microbiology; La Trobe University; Bundoora Vic. Australia
| | - D. H. Hryciw
- Department of Physiology; The University of Melbourne; Parkville Vic. Australia
| | - M. E. Wlodek
- Department of Physiology; The University of Melbourne; Parkville Vic. Australia
| | - K. M. Moritz
- School of Biomedical Sciences; The University of Queensland; St. Lucia Qld Australia
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2
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Richter VFI, Briffa JF, Moritz KM, Wlodek ME, Hryciw DH. The role of maternal nutrition, metabolic function and the placenta in developmental programming of renal dysfunction. Clin Exp Pharmacol Physiol 2016; 43:135-41. [PMID: 26475203 DOI: 10.1111/1440-1681.12505] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 09/21/2015] [Accepted: 10/12/2015] [Indexed: 11/27/2022]
Abstract
The intrauterine environment is critical for the development of the foetus. Barker and colleagues were the first to identify that adverse perturbations during foetal development are associated with an increased risk of developing diseases in adulthood, including cardiorenal disease. Specifically for the kidney, perturbations in utero can lead to nephron deficits and renal dysfunction by a number of mechanisms. Altered programming of nephron number is associated with an increased risk of developing kidney disease via glomerular hypertrophy and reduced vasodilative capacity of the renal blood vessels; both of which would contribute to hypertension in adulthood, with males being more susceptible to disease outcomes. Additionally, alterations in the renin-angiotensin system (RAS) such as an upregulation or downregulation of specific receptors, depending on the nature of the insult, have also been implicated in the development of renal dysfunction. Sex-specific differences in the expression of the RAS during late gestation and in the early postnatal environment have also been identified. Extensive research has demonstrated that both uteroplacental insufficiency and maternal malnutrition alter renal development in utero. Equally, exposure to maternal diabetes and maternal obesity during development are also associated with an increased risk of developing renal disease, however, the mechanism behind this association is poorly understood. Therefore, identifying the link between an adverse intrauterine environment and the programmed kidney disease risk in adulthood may facilitate the development of strategies to alleviate the epidemics of cardiorenal disease worldwide, in addition to understanding why males are more susceptible to adult-onset cardiovascular diseases.
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Affiliation(s)
- V F I Richter
- Department of Physiology, The University of Melbourne, Parkville, Vic., Australia
| | - J F Briffa
- Department of Physiology, The University of Melbourne, Parkville, Vic., Australia
| | - K M Moritz
- School of Biomedical Sciences, University of Queensland, St. Lucia, Qld, Australia
| | - M E Wlodek
- Department of Physiology, The University of Melbourne, Parkville, Vic., Australia
| | - D H Hryciw
- Department of Physiology, The University of Melbourne, Parkville, Vic., Australia
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Briffa JF, Grinfeld E, Jenkin KA, Mathai ML, Poronnik P, McAinch AJ, Hryciw DH. Diet induced obesity in rats reduces NHE3 and Na(+) /K(+) -ATPase expression in the kidney. Clin Exp Pharmacol Physiol 2016; 42:1118-26. [PMID: 26173747 DOI: 10.1111/1440-1681.12452] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 06/25/2015] [Accepted: 07/01/2015] [Indexed: 01/25/2023]
Abstract
The consumption of a high fat diet (HFD) is associated with proteinuria and altered sodium handling and excretion, which can lead to kidney disease. In the proximal tubule, the Na(+) /H(+) Exchanger 3 (NHE3) is responsible for normal protein reabsorption and the reabsorption of approximately 70% of the renal sodium load. It is the Na(+) /K(+) -ATPase that provides the driving force for the reabsorption of sodium and its exit across the basolateral membrane. This study investigates the effects that consumption of a HFD for 12 weeks has on NHE3 and Na(+) /K(+) -ATPase expression in the kidney. Western blot analysis identified a significant reduction in NHE3 and its modulator, phosphorylated protein kinase B, in renal lysate from obese rats. In the obese rats, a reduction in NHE3 expression in the proximal tubule may impact on the acidification of endosomes which are responsible for albumin uptake, suggesting a key role for the exchanger in protein endocytosis in obesity. Western blot analysis identified a reduction in Na(+) /K(+) -ATPase which could also potentially impact on albumin uptake and sodium reabsorption. This study demonstrates that consumption of a HFD for 12 weeks reduces renal NHE3 and Na(+) /K(+) -ATPase expression, an effect that may contribute to the albuminuria associated with obesity. Furthermore the reduction in these transporters is not likely to contribute to the reduced sodium excretion in obesity. These data highlight a potential link between NHE3 and Na(+) /K(+) -ATPase in the pathophysiological changes in renal protein handling observed in obesity.
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Affiliation(s)
- J F Briffa
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans, Victoria, Australia.,Department of Physiology, The University of Melbourne, Parkville, Victoria, Australia
| | - E Grinfeld
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans, Victoria, Australia
| | - K A Jenkin
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans, Victoria, Australia
| | - M L Mathai
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans, Victoria, Australia
| | - P Poronnik
- Department of Physiology, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - A J McAinch
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans, Victoria, Australia
| | - D H Hryciw
- Department of Physiology, The University of Melbourne, Parkville, Victoria, Australia
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Jenkin KA, O'Keefe L, Simcocks AC, Briffa JF, Mathai ML, McAinch AJ, Hryciw DH. Renal effects of chronic pharmacological manipulation of CB2 receptors in rats with diet-induced obesity. Br J Pharmacol 2015; 173:1128-42. [PMID: 25537025 DOI: 10.1111/bph.13056] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 12/02/2014] [Accepted: 12/11/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE In diabetic nephropathy agonism of CB2 receptors reduces albuminuria and podocyte loss; however, the role of CB2 receptors in obesity-related nephropathy is unknown. The aim of this study was to determine the role of CB2 receptors in a model of diet-induced obesity (DIO) and characterize the hallmark signs of renal damage in response to agonism (AM1241) and antagonism (AM630) of CB2 receptors. EXPERIMENTAL APPROACH Male Sprague Dawley rats were fed a high-fat diet (HFD: 40% digestible energy from lipids) for 10 weeks. In another cohort, after 9 weeks on a HFD, rats were injected daily with either 3 mg·kg(-1) AM1241, 0.3 mg·kg(-1) AM630 or saline for 6 weeks. KEY RESULTS Ten weeks on a HFD significantly reduced renal expression of CB2 receptors and renal function. Treatment with AM1241 or AM630 did not reduce weight gain or food consumption in DIO. Despite this, AM1241 significantly reduced systolic BP, peri-renal adipose accumulation, plasma leptin, urinary protein, urinary albumin, urinary sodium excretion and the fibrotic markers TGF-β1, collagen IV and VEGF in kidney lysate. Treatment with AM630 of DIO rats significantly reduced creatinine clearance and increased glomerular area and kidney weight (gross and standardized for body weight). Diastolic BP, glucose tolerance, insulin sensitivity, plasma creatinine, plasma TGF-β1 and kidney expression of fibronectin and α-smooth muscle actin were not altered by either AM1241 or AM630 in DIO. CONCLUSIONS This study demonstrates that while agonism of CB2 receptors with AM1241 treatment for 6 weeks does not reduce weight gain in obese rats, it leads to improvements in obesity-related renal dysfunction. LINKED ARTICLES This article is part of a themed section on Endocannabinoids. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.7/issuetoc.
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Affiliation(s)
- K A Jenkin
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans Campus, Melbourne, Vic., Australia
| | - L O'Keefe
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans Campus, Melbourne, Vic., Australia
| | - A C Simcocks
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans Campus, Melbourne, Vic., Australia
| | - J F Briffa
- Department of Physiology, University of Melbourne, Melbourne, Vic., Australia
| | - M L Mathai
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans Campus, Melbourne, Vic., Australia.,The Florey Institute of Neuroscience and Mental Health, Melbourne, Vic., Australia
| | - A J McAinch
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St Albans Campus, Melbourne, Vic., Australia
| | - D H Hryciw
- Department of Physiology, University of Melbourne, Melbourne, Vic., Australia
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Slattery C, Jang Y, Kruger WA, Hryciw DH, Lee A, Poronnik P. γ-Secretase inhibition promotes fibrotic effects of albumin in proximal tubular epithelial cells. Br J Pharmacol 2014; 169:1239-51. [PMID: 23594166 DOI: 10.1111/bph.12214] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 01/24/2013] [Accepted: 02/20/2013] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND AND PURPOSE Albuminuria is an important biomarker of renal dysfunction and is a major mediator of renal damage and fibrosis during kidney disease. The mechanisms underlying albumin-induced renal fibrosis remain unclear. There has been significant interest in γ-secretase activity in tubular epithelial cells in recent times; however, its potential role in albumin-induced fibrosis has not been investigated. EXPERIMENTAL APPROACH The primary aim of this study was to examine the role of γ-secretase in albumin-induced fibrotic effects in proximal tubular cells. The effects of increasing albumin concentrations on fibrosis indicators and mediators in the human HK-2 cell line were examined in the presence and absence of a γ-secretase inhibitor, compound E. KEY RESULTS Treatment with albumin resulted in a number of pro-fibrotic effects, including up-regulation of fibronectin, TGF-β1 and the EGF-R. Interestingly, similar effects were observed in response to treatment with the γ-secretase inhibitor, compound E. Co-treatment of cells with albumin and an EGF-R inhibitor, AG-1478, resulted in significant inhibition of the observed pro-fibrotic effects, suggesting a major role for the EGF-R in albumin-induced fibrotic events. Albumin-induced effects on the EGF-R appeared to be mediated through inhibition of γ-secretase activity and were dependent on ERK-MAPK signalling. CONCLUSIONS AND IMPLICATIONS These results provide novel insights into the mechanisms of albumin-induced fibrotic effects in tubular epithelial cells, suggesting important roles for the γ-secretase and the EGF-R. These results suggest that the proposed use of γ-secretase inhibitors as anti-fibrotic agents requires further investigation.
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Affiliation(s)
- C Slattery
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Belfield, Ireland
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6
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O'Keefe L, Simcocks AC, Hryciw DH, Mathai ML, McAinch AJ. The cannabinoid receptor 1 and its role in influencing peripheral metabolism. Diabetes Obes Metab 2014; 16:294-304. [PMID: 23782485 DOI: 10.1111/dom.12144] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/02/2013] [Accepted: 06/11/2013] [Indexed: 12/27/2022]
Abstract
Evidence from in vitro and in vivo studies has demonstrated the deleterious pathological effects of a dysregulated endocannabinoid system. Increased stimulation of the cannabinoid receptor 1 (CB1 ) and subsequent downstream cellular signalling are both causative in the deleterious pathological effects observed in a number of diseases. When the CB1 cell signalling cascade is blocked, this results in whole body weight-loss, leading to a reduction in obesity and associated co-morbidities. In the central nervous system; however, CB1 antagonism results in adverse psychological side effects. Blockade of CB1 via peripheral acting compounds that do not cross the blood-brain barrier have been determined to have beneficial effects in metabolic tissues such as the liver and skeletal muscle. These results support the notion that peripheral blockade of CB1 using pharmacological antagonists is a viable target for the treatment of the current epidemic of obesity and its associated co-morbidities.
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Affiliation(s)
- L O'Keefe
- Biomedical and Lifestyle Disease Unit, College of Health and Biomedicine, Victoria University, Victoria, Australia
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7
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Cornall LM, Mathai ML, Hryciw DH, Simcocks AC, O'Brien PE, Wentworth JM, McAinch AJ. GPR119 regulates genetic markers of fatty acid oxidation in cultured skeletal muscle myotubes. Mol Cell Endocrinol 2013; 365:108-18. [PMID: 23069642 DOI: 10.1016/j.mce.2012.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 10/01/2012] [Accepted: 10/03/2012] [Indexed: 12/16/2022]
Abstract
Gene knockout and agonist studies indicate that activation of the G protein-coupled receptor, GPR119, protects against diet-induced obesity and insulin resistance. It is not known if GPR119 activation in skeletal muscle mediates these effects. To address this uncertainty, we measured GPR119 expression in skeletal muscle and determined the effects of PSN632408, a GPR119 agonist, on the expression of genes and proteins required for fatty acid and glucose oxidation in cultured myotubes. GPR119 expression was readily detected in rat skeletal muscle and mRNAs were induced by 12 weeks of high-fat feeding. Treatment of cultured mouse C₂C₁₂ myotubes with 5 μM PSN632408 or 0.5 mM palmitate reduced expression of mRNAs encoding fatty acid oxidation genes to similar extents. More so, treatment with PSN632408 decreased AMPKα (Thr172 phosphorylation) activity in the absence of palmitate and ACC (Ser79 phosphorylation) activity in the presence of palmitate. In human primary myotubes PSN632408 decreased expression of PDK4 and AMPKα2 mRNA in myotubes derived from obese donors. These data suggest GPR119 activation in skeletal muscle may impair fatty acid and glucose oxidation.
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MESH Headings
- Acids, Heterocyclic/pharmacology
- Adult
- Animals
- Body Mass Index
- Cells, Cultured
- Clone Cells
- Fatty Acids, Nonesterified/metabolism
- Female
- Gene Expression Regulation/drug effects
- Genetic Markers
- Glucose/metabolism
- Humans
- Male
- Mice
- Middle Aged
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Obesity, Morbid/genetics
- Obesity, Morbid/metabolism
- Obesity, Morbid/pathology
- Oxadiazoles/pharmacology
- Random Allocation
- Rats
- Rats, Sprague-Dawley
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
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Affiliation(s)
- L M Cornall
- Biomedical and Lifestyle Diseases Unit, School of Biomedical and Health Sciences, Victoria University, Melbourne 8001, Australia.
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Hryciw DH, Jenkin KA, Simcocks AC, Grinfeld E, McAinch AJ, Poronnik P. The interaction between megalin and ClC-5 is scaffolded by the Na⁺-H⁺ exchanger regulatory factor 2 (NHERF2) in proximal tubule cells. Int J Biochem Cell Biol 2012; 44:815-23. [PMID: 22349218 DOI: 10.1016/j.biocel.2012.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 01/22/2012] [Accepted: 02/05/2012] [Indexed: 11/25/2022]
Abstract
Albumin endocytosis in the proximal tubule is mediated by a number of proteins, including the scavenger receptor megalin/cubilin and the PSD-95/Dlg/ZO-1 (PDZ) scaffolds NHERF1 and NHERF2. In addition, in a number of in vitro and in vivo models, the loss of ClC-5 results in a decreased cell surface expression and whole cell level of megalin, suggesting an interaction between these two proteins in vivo. We investigated if ClC-5 and megalin interact directly, and as ClC-5 binds to NHERF2, we investigated if this PDZ scaffold was required for a megalin/ClC-5 complex. GST-pulldown and immunoprecipitation experiments using rat kidney lysate demonstrated an interaction between ClC-5 and megalin, which was mediated by their C-termini. As this interaction may be controlled by a scaffold protein, we characterised any interaction between megalin and NHERF2. Immunoprecipitation experiments indicated that megalin interacts with NHERF2 in vivo, and that this interaction was via an internal NHERF binding domain in the C-terminus of megalin and PDZ2 and the C-terminus of NHERF2. Silencing NHERF2 had no effect on megalin protein levels in the whole cell or plasma membrane. Using siRNA against NHERF2, we demonstrated that NHERF2 was required to facilitate the interaction between megalin and ClC-5. Using fusion proteins, we characterised a protein complex containing ClC-5 and megalin, which is scaffolded by NHERF2, in the absence of any other proteins. Importantly, these observations are the first to describe an interaction between megalin and ClC-5, which is scaffolded by NHERF2 in proximal tubule cells.
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Affiliation(s)
- D H Hryciw
- Biomedical and Lifestyle Diseases Unit, School of Biomedical and Health Sciences, Victoria University, St Albans, VIC 3021, Australia.
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Hryciw DH, Guggino WB. Cystic fibrosis transmembrane conductance regulator and the outwardly rectifying chloride channel: a relationship between two chloride channels expressed in epithelial cells. Clin Exp Pharmacol Physiol 2000; 27:892-5. [PMID: 11071305 DOI: 10.1046/j.1440-1681.2000.03356.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) result in the primary defect observed in patients with cystic fibrosis. 2. The CFTR is a member of the ATPase-binding cassette (ABC) transporter family but, unlike other members of this group, CFTR conducts a chloride current that is activated by cAMP. 3. In epithelial cells, the cAMP-stimulated chloride current is conducted by both CFTR and the outwardly rectifying chloride channel (ORCC). 4. The present review summarizes the current knowledge of the properties of the two channels, as well as their relationship. Because the gene encoding the ORCC has not been identified, a discussion as to possible candidates for this chloride channel is included.
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Affiliation(s)
- D H Hryciw
- Department of Physiology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
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Abstract
Although hydropathy analysis of the skeletal muscle chloride channel protein, ClC-1, initially predicted 13 potential membrane spanning domains (D1 to D13), later topological studies have suggested that domain D4 is extracellular and that D13, conserved in all eukaryotic ClC channels, is located within the extensive cytoplasmic tail that makes up the carboxyl terminus of the protein. We have examined the effect of deleting D13 (DeltaD13) and the function of the carboxyl tail by removing the final 72 (fs923X), 100 (fs895X), 125 (L869X), 398 (N596X), and 420 (Q574X) amino acids from rat ClC-1. Appropriate cDNA constructs were prepared and expressed using the baculovirus Sf9 insect cell system. Patch clamp analysis of chloride currents in Sf9 cells showed that only relatively insubstantial changes could be attributed to the expressed fs923X, fs895X, and DeltaD13 mutants compared with wild type rat ClC-1. For N596X and Q574X, however, adequate mRNA could be detected, but neither patch clamp nor polyacrylamide gel electrophoresis showed corresponding protein production. By contrast, expression of L869X was demonstrable by polyacrylamide gel electrophoresis, but no chloride conductance attributable to it could be detected. Overall, our results indicate that the domain D13 is dispensable, as are the final 100 amino acids, but not the final 125 amino acids or more, of the carboxyl tail. Some essential region of unknown significance, therefore, appears to reside in the 18 amino acids after D13, from Lys877 to Arg894.
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Affiliation(s)
- D H Hryciw
- Centre for Advanced Biomedical Studies, University of South Australia, North Terrace, Adelaide, South Australia 5000, Australia
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