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Matchimakul P, Pongkan W, Kongtung P, Mektrirat R. Comparative quantitation of aquaporin-2 and arginine vasopressin receptor-2 localizations among chronic kidney disease and healthy kidney in dogs. Vet World 2021; 14:2773-2781. [PMID: 34903939 PMCID: PMC8654747 DOI: 10.14202/vetworld.2021.2773-2781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/09/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND AND AIM Aquaporin-2 (AQP2) and arginine vasopressin receptor-2 (AVPR2) are proteins that control water homeostasis in principal cells. Chronic kidney disease (CKD) is defined as the impairment and irreversible loss of kidney function and/or structure, which causes water imbalances and polyuria. The study aimed to know the expression of AQPs and AVPR2 in the kidneys of a canine with CKD. MATERIALS AND METHODS The kidneys were collected from two dog carcasses from Small Animal Teaching Hospital, Faculty of Veterinary Medicine, Chiang Mai University. The kidney tissue was prepared for immunohistochemistry and investigated the expression and localization of tissue's AQP2 and AVPR2. For statistical analysis, the Mann-Whitney U-test was applied to the data. RESULTS By immunohistochemistry, AQP2 was expressed strongly in the basolateral and apical membranes of the principal cells, whereas AVPR2 was localized in the principal cell's basolateral membrane in both renal cortex and renal medulla. In the normal kidney, the semi-quantitative immunohistochemistry for the percentage of protein expression of AQP2 and AVPR2 was 5.062±0.4587 and 4.306±0.7695, respectively. In contrast, protein expression of AQP2 and AVPR2 in CKD was found to be 1.218±0.1719 and 0.8536±0.1396, respectively. The data shows that the percentage of AQP2 and AVPR2 expression was decreased, corresponding to a 4-fold and 5-fold in CKD (p<0.001). CONCLUSION Our findings revealed that CKD was a marked decrease in AQP2 and AVPR2 expression. The central role of specific AQP2 and AVPR2 in regulating water homeostasis will provide correlations in case of CKD with polyuria.
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Affiliation(s)
- Pitchaya Matchimakul
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Wanpitak Pongkan
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Piyamat Kongtung
- Central Laboratory, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Raktham Mektrirat
- Department of Veterinary Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
- Integrative Research Center for Veterinary Circulatory Sciences, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
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Corallodiscus flabellata B.L. Burtt Extracts Stimulate Diuretic Activity and Regulate the Renal Expression of Aquaporins. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:6020817. [PMID: 32190088 PMCID: PMC7064869 DOI: 10.1155/2020/6020817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 08/18/2019] [Accepted: 09/25/2019] [Indexed: 11/21/2022]
Abstract
Corallodiscus flabellata B. L. Burtt is a traditional Chinese medicine. Previous studies in our laboratory showed that C. flabellata alleviated symptoms of Alzheimer's disease (AD) in a rat model of AD and increased healthy rats' urine volume. The aims of this study were to explore the diuretic activity of different extracts from C. flabellata and to identify the underlying mechanisms of action. Different doses of a C. flabellata extract (CF-L, CF-M, and CF-H) were administered orally to male KM mice in a single dose. In another procedure, C. flabellata (CF), water extract, and 20%, 30%, and 40% ethanol extracts of C. flabellata (CF-WE, CF-20, CF-30, and CF-40) were administered orally daily for 5 days. The urinary excretion rate, osmolality, and electrolyte levels in urine and serum, renal expression of aquaporins (AQPs), apoptosis-related protein, and MAPK-related protein were analyzed. The results showed that single doses of CF-M and CF-H increased urinary volume significantly, as well as daily administration of CF, CF-WE, CF-20, CF-30, and CF-40. Furthermore, CF-20 and CF-30 increased the concentration of Na+ in the urine. Treatment with CF-40 increased the urine osmolality and Na+ and Cl− concentrations and decreased the concentration of Na+ in the serum. Also, CF, CF-WE, CF-20, CF-30, and CF-40 decreased the renal expression of AQPs, as well as the ratios of Bcl-2/Bax, p-ERK/ERK, p-JNK/JNK, and p-p38/p38. In sum, the medium and high doses of the C. flabellata extract and CF-WE, CF-20, CF-30, and CF-40 were found to have a diuretic activity. They may inhibit the renal expression of AQPs and apoptosis-related proteins by inhibiting the MAPK signaling pathway, thereby achieving diuretic effects.
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Lu TJ, Kan WC, Yang SS, Jiang ST, Wu SN, Ling P, Bao BY, Lin CY, Yang ZY, Weng YP, Chan CH, Lu TL. MST3 is involved in ENaC-mediated hypertension. Am J Physiol Renal Physiol 2019; 317:F30-F42. [PMID: 30969802 DOI: 10.1152/ajprenal.00455.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Liddle syndrome is an inherited form of human hypertension caused by increasing epithelial Na+ channel (ENaC) expression. Increased Na+ retention through ENaC with subsequent volume expansion causes hypertension. In addition to ENaC, the Na+-K+-Cl- cotransporter (NKCC) and Na+-Cl- symporter (NCC) are responsible for Na+ reabsorption in the kidneys. Several Na+ transporters are evolutionarily regulated by the Ste20 kinase family. Ste20-related proline/alanine-rich kinase and oxidative stress-responsive kinase-1 phosphorylate downstream NKCC2 and NCC to maintain Na+ and blood pressure (BP) homeostasis. Mammalian Ste20 kinase 3 (MST3) is another member of the Ste20 family. We previously reported that reduced MST3 levels were found in the kidneys in spontaneously hypertensive rats and that MST3 was involved in Na+ regulation. To determine whether MST3 is involved in BP stability through Na+ regulation, we generated a MST3 hypomorphic mutation and designated MST3+/- and MST3-/- mice to examine BP and serum Na+ and K+ concentrations. MST3-/- mice exhibited hypernatremia, hypokalemia, and hypertension. The increased ENaC in the kidney played roles in hypernatremia. The reabsorption of more Na+ promoted more K+ secretion in the kidney and caused hypokalemia. The hypernatremia and hypokalemia in MST3-/- mice were significantly reversed by the ENaC inhibitor amiloride, indicating that MST3-/- mice reabsorbed more Na+ through ENaC. Furthermore, Madin-Darby canine kidney cells stably expressing kinase-dead MST3 displayed elevated ENaC currents. Both the in vivo and in vitro results indicated that MST3 maintained Na+ homeostasis through ENaC regulation. We are the first to report that MST3 maintains BP stability through ENaC regulation.
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Affiliation(s)
- Te-Jung Lu
- Department of Medical Laboratory Science and Biotechnology, Chung Hwa University of Medical Technology , Tainan , Taiwan
| | - Wei-Chih Kan
- Department of Nephrology, Chi-Mei Medical Center , Tainan , Taiwan.,Department of Biological Science and Technology, Chung Hwa University of Medical Technology , Tainan , Taiwan
| | - Sung-Sen Yang
- Division of Nephrology, Department of Medicine, Tri-service General Hospital, Graduate Institute of Medical Sciences, National Defense Medical Center , Taipei , Taiwan
| | - Si-Tse Jiang
- Department of Research and Development, National Laboratory Animal Center, National Applied Research Laboratories , Tainan , Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Pin Ling
- Department of Physiology, College of Medicine, National Cheng Kung University , Tainan , Taiwan.,Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University , Tainan , Taiwan
| | - Bo-Ying Bao
- School of Pharmacy, China Medical University , Taichung , Taiwan
| | - Chia-Yu Lin
- Department of Medical Laboratory Science and Biotechnology, China Medical University , Taichung , Taiwan
| | - Zin-Ya Yang
- Department of Medical Laboratory Science and Biotechnology, China Medical University , Taichung , Taiwan
| | - Yui-Ping Weng
- Department of Biological Science and Technology, Chung Hwa University of Medical Technology , Tainan , Taiwan
| | - Chee-Hong Chan
- Department of Nephrology, Chang Bing Show Chwan Memorial Hospital, Lukang, Changhua, Taiwan
| | - Te Ling Lu
- School of Pharmacy, China Medical University , Taichung , Taiwan
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Schimming BC, Baumam CAE, Pinheiro PFF, de Matteis R, Domeniconi RF. Aquaporin 9 is expressed in the epididymis of immature and mature pigs. Reprod Domest Anim 2017; 52:617-624. [DOI: 10.1111/rda.12957] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/09/2017] [Indexed: 01/17/2023]
Affiliation(s)
- BC Schimming
- Department of Anatomy; Institute of Biosciences; São Paulo State University (UNESP); Botucatu SP Brazil
| | - CAE Baumam
- School of Veterinary Medicine and Animal Science; São Paulo State University (UNESP); Botucatu SP Brazil
| | - PFF Pinheiro
- Department of Anatomy; Institute of Biosciences; São Paulo State University (UNESP); Botucatu SP Brazil
| | - R de Matteis
- School of Veterinary Medicine and Animal Science; São Paulo State University (UNESP); Botucatu SP Brazil
| | - RF Domeniconi
- Department of Anatomy; Institute of Biosciences; São Paulo State University (UNESP); Botucatu SP Brazil
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Ewida SF, Al-Sharaky DR. Implication of Renal Aquaporin-3 in Fructose-Induced Metabolic Syndrome and Melatonin Protection. J Clin Diagn Res 2016; 10:CF06-11. [PMID: 27190797 DOI: 10.7860/jcdr/2016/18362.7656] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/21/2016] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Metabolic Syndrome (MetS) can be induced by ingestion of large amounts of fructose as a consequence of oxidative stress and dyslipidemia. AIM We investigated the possible protective effects of melatonin administration on MetS induced in fructose-fed rats with special focus on the role of renal aquaporin-3 (AQP-3). MATERIALS AND METHODS Thirty rats were randomly divided into three groups; control, fructose, and fructose plus melatonin. MetS was induced by fructose rich diet and melatonin was injected at a dose of 5 mg/kg dissolved in 1% ethanol in normal saline. After the end of the 6-week experimental period, body weight and fat accretion were assessed. Invasive blood pressure and vascular reactivity were evaluated. Serum lipid profile, glucose, insulin levels, insulin resistance, malondialdehyde (MDA) and uric acid were measured, also underwent renal AQP-3 immunohistochemistry. RESULTS Fructose consumption significantly increased fat accretion, systolic blood pressure, serum lipids, insulin levels and insulin resistance, confirming successful establishment of the MetS model. Also serum MDA, uric acid and renal AQP-3 expression increased compared to the control group. Melatonin supplementation significantly decreased the previously measured parameters compared to fructose group. CONCLUSION Increased AQP-3 expression may be implicated in fructose induced MetS. Melatonin protective effect against metabolic consensus and vascular affection may be linked to its antioxidant and lipid lowering effect with reduced renal AQP-3 expression.
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Affiliation(s)
- Suzy Fayez Ewida
- Faculty of Medicine, Department of Physiology, Menoufia University , Egypt
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Altunbas K, Cevik–Demirkan A, Ozden-Akkaya O, Akosman MS. Renal expression and functions of aquaporin 1 and aquaporin 4 in cattle. Biotech Histochem 2013; 88:350-5. [DOI: 10.3109/10520295.2013.789126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Radin MJ, Yu MJ, Stoedkilde L, Miller RL, Hoffert JD, Frokiaer J, Pisitkun T, Knepper MA. Aquaporin-2 regulation in health and disease. Vet Clin Pathol 2012; 41:455-70. [PMID: 23130944 PMCID: PMC3562700 DOI: 10.1111/j.1939-165x.2012.00488.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Aquaporin-2 (AQP2), the vasopressin-regulated water channel of the renal collecting duct, is dysregulated in numerous disorders of water balance in people and animals, including those associated with polyuria (urinary tract obstruction, hypokalemia, inflammation, and lithium toxicity) and with dilutional hyponatremia (syndrome of inappropriate antidiuresis, congestive heart failure, cirrhosis). Normal regulation of AQP2 by vasopressin involves 2 independent regulatory mechanisms: (1) short-term regulation of AQP2 trafficking to and from the apical plasma membrane, and (2) long-term regulation of the total abundance of the AQP2 protein in the cells. Most disorders of water balance are the result of dysregulation of processes that regulate the total abundance of AQP2 in collecting duct cells. In general, the level of AQP2 in a collecting duct cell is determined by a balance between production via translation of AQP2 mRNA and removal via degradation or secretion into the urine in exosomes. AQP2 abundance increases in response to vasopressin chiefly due to increased translation subsequent to increases in AQP2 mRNA. Vasopressin-mediated regulation of AQP2 gene transcription is poorly understood, although several transcription factor-binding elements in the 5' flanking region of the AQP2 gene have been identified, and candidate transcription factors corresponding to these elements have been discovered in proteomics studies. Here, we review progress in this area and discuss elements of vasopressin signaling in the collecting duct that may impinge on regulation of AQP2 in health and in the context of examples of polyuric diseases.
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Affiliation(s)
- M. Judith Radin
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH
| | - Ming-Jiun Yu
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
- Institute of Biochemistry and Molecular Biology, National Taiwan University College of Medicine, Taipei, TAIWAN
| | - Lene Stoedkilde
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
- The Water and Salt Research Center, University of Aarhus, DK-8000 C, Denmark
| | - R. Lance Miller
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jason D. Hoffert
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jorgen Frokiaer
- The Water and Salt Research Center, University of Aarhus, DK-8000 C, Denmark
| | - Trairak Pisitkun
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Mark A. Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
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Iacovetta C, Rudloff E, Kirby R. The role of aquaporin 4 in the brain. Vet Clin Pathol 2012; 41:32-44. [PMID: 22250904 DOI: 10.1111/j.1939-165x.2011.00390.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Revised: 11/14/2011] [Accepted: 12/10/2011] [Indexed: 11/26/2022]
Abstract
Emerging evidence suggests that aquaporin (AQP) 4 water channels play an important role in water homeostasis in the brain. These water channels are most abundant in the cell membrane of astrocytes, but are also present within ependymal cell membranes and in osmosensory areas of the hypothalamus. Water transport through AQP4 depends on concentration gradients across the membrane, but the rate of transport is determined by the capacity of astrocytes to up- and down-regulate AQP4 numbers, their location within the membrane, and the overall permeability of the channel. Other functions of brain AQP4 involve potassium uptake and release by astrocytes, migration of glial cells, glial scarring, and astrocyte-to-astrocyte cell communication. AQP water channels are involved in formation and control of edema in the brain and in multiple disease processes in the brain, such as seizures and tumors. There is abundant scientific literature on AQP4 describing its structure, function, location, and role in water homeostasis and edema in the brain. Investigation of AQP expression in the canine and feline brain should be pursued so that clinically relevant comparisons between findings in mice, rats, and people and animal patients can be made.
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Abstract
Diabetes insipidus (DI) is a rare disorder of horses characterized by profound polyuria and polydipsia (PU/PD), which can be caused by loss of production of arginine vasopressin (AVP). This condition is termed neurogenic or central DI. DI may also develop with absence or loss of AVP receptors or activity on the basolateral membrane of collecting-duct epithelial cells. This condition is termed nephrogenic DI. Equine clinicians may differentiate true DI from more common causes of PU/PD by a systematic diagnostic approach. DI may not be a correctable disorder, and supportive care of affected horses requires an adequate water source.
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Mobasheri A, Kendall BH, Maxwell JEJ, Sawran AV, German AJ, Marples D, Luck MR, Royal MD. Cellular localization of aquaporins along the secretory pathway of the lactating bovine mammary gland: an immunohistochemical study. Acta Histochem 2011; 113:137-49. [PMID: 19853284 DOI: 10.1016/j.acthis.2009.09.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 09/14/2009] [Accepted: 09/16/2009] [Indexed: 10/20/2022]
Abstract
In this study we examined the cellular localization of aquaporins (AQPs) along the secretory pathway of actively lactating bovine mammary glands using immunohistochemistry. Mammary tissues examined included secretory ducts and acini, gland cisterns, teats, stromal and adipose tissues. Aquaporin 1 (AQP1) was localized in capillary endothelia throughout the mammary gland in addition to myoepithelial cells underlying teat duct epithelia. AQP2 and AQP6 were not detected and AQP9 was found only in leukocytes. AQP3 and AQP4 were observed in selected epithelial cells in the teat, cistern and secretory tubuloalveoli. AQP5 immunopositivity was prominent in the cistern. AQP3 and AQP7 were found in smooth muscle bundles in the teat, secretory epithelial cells and duct epithelial cells. These immunohistochemical findings support a functional role for aquaporins in the transport of water and small solutes across endothelial and epithelial barriers in the mammary gland and in the production and secretion of milk.
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Cornock R, Langley-Evans SC, Mobasheri A, McMullen S. The impact of maternal protein restriction during rat pregnancy upon renal expression of angiotensin receptors and vasopressin-related aquaporins. Reprod Biol Endocrinol 2010; 8:105. [PMID: 20807409 PMCID: PMC2940793 DOI: 10.1186/1477-7827-8-105] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Accepted: 08/31/2010] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Maternal protein restriction during rat pregnancy is known to impact upon fetal development, growth and risk of disease in later life. It is of interest to understand how protein undernutrition influences the normal maternal adaptation to pregnancy. Here we investigated the mechanisms regulating renal haemodynamics and plasma volume during pregnancy, in the context of both normal and reduced plasma volume expansion. The study focused on expression of renal angiotensin receptors (ATR) and vasopressin-related aquaporins (AQP), hypothesising that an alteration in the balance of these proteins would be associated with pregnancy per se and with compromised plasma volume expansion in rats fed a low-protein diet. METHODS Female Wistar rats were mated and fed a control (18% casein) or low-protein (9% casein) diet during pregnancy. Animals were anaesthetised on days 5, 10, 15 and 20 of gestation (n = 8/group/time-point) for determination of plasma volume using Evans Blue dye, prior to euthanasia and collection of tissues. Expression of the ATR subtypes and AQP2, 3 and 4 were assessed in maternal kidneys by PCR and western blotting. 24 non-pregnant Wistar rats underwent the same procedure at defined points of the oestrous cycle. RESULTS As expected, pregnancy was associated with an increase in blood volume and haemodilution impacted upon red blood cell counts and haemoglobin concentrations. Expression of angiotensin II receptors and aquaporins 2, 3 and 4 was stable across all stages of the oestrus cycle. Interesting patterns of intra-renal protein expression were observed in response to pregnancy, including a significant down-regulation of AQP2. In contrast to previous literature and despite an apparent delay in blood volume expansion in low-protein fed rats, blood volume did not differ significantly between groups of pregnant animals. However, a significant down-regulation of AT2R protein expression was observed in low-protein fed animals alongside a decrease in creatinine clearance. CONCLUSION Regulatory systems involved in the pregnancy-induced plasma volume expansion are susceptible to the effects of maternal protein restriction.
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Affiliation(s)
- Ruth Cornock
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Simon C Langley-Evans
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Ali Mobasheri
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Sarah McMullen
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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Summerfield N, Peters ME, Hercock CA, Mobasheri A, Young IS. Immunohistochemical evidence for expression of fast-twitch type sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA1) in German shepherd dogs with dilated cardiomyopathy myocardium. J Vet Cardiol 2010; 12:17-23. [PMID: 20188644 DOI: 10.1016/j.jvc.2009.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 12/04/2009] [Accepted: 12/11/2009] [Indexed: 10/19/2022]
Abstract
OBJECTIVES Dilated cardiomyopathy (DCM) is one of the most common acquired canine heart diseases. It is particularly common in large and giant breed dogs. Although a great deal is known about the clinical progression and manifestations of the disease, the underlying cellular and molecular mechanisms remain poorly understood. One widely held belief is that calcium-handling abnormalities are critically involved in the disease process. This study investigates the changes in expression of the sarco(endo)plasmic reticulum calcium ATPase (SERCA) isoforms in DCM myocardium from German shepherd dogs. ANIMALS, MATERIALS AND METHODS Affected tissue samples were obtained from German shepherd dogs with DCM, euthanized for intractable congestive heart failure while normal myocardial tissue samples were obtained from German shepherd dogs, euthanized for non-cardiovascular reasons. Tissue microarrays containing normal and DCM myocardium samples were prepared, immunostained with SERCA1 and SERCA2 antibodies and analyzed. RESULTS We were able to demonstrate, for the first time, that while there is little change in the expression of the cardiac isoform (SERCA2), there is clear expression of the fast-twitch skeletal muscle isoform SERCA1 in the myocardium of dogs diagnosed with DCM. CONCLUSION We propose that SERCA1 expression is evidence of a natural adaptive response to the impaired Ca2+ handling thought to occur in German shepherd dogs with DCM and heart failure.
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Affiliation(s)
- Nuala Summerfield
- North Downs Specialist Referrals, Bletchingley, Surrey RH1 4QP, United Kingdom
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Floyd RV, Wray S, Quenby S, Martín-Vasallo P, Mobasheri A. Expression and distribution of Na, K-ATPase isoforms in the human uterus. Reprod Sci 2010; 17:366-76. [PMID: 20065300 DOI: 10.1177/1933719109355196] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Na, K-ATPase activity relies on the composition of its catalytic alpha, beta, and FXYD constituents, all of which are expressed as multiple isoforms (4alpha, 4beta, and 7 FXYD). We used reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry to study Na, K-ATPase expression in uterine samples from nonlaboring elective and laboring emergency caesarean sections (CSs). Transcripts of alpha1 to 3, beta1 to 3, and FXYD1 isoforms were detected in all samples, but FXYD2 was only present in hysterectomy samples. Abundant immunoreactivity of alpha1 and moderate alpha2 was localized in myometrial smooth muscle and secretory glands of all groups. Smooth muscle and gland epithelia showed diffuse cytoplasmic alpha3 immunoreactivity. beta isoforms were detected in all groups but beta3 showed much denser immunoreactivity in myometrial samples taken from women in labor. In pregnancy, there was a switch in isoform expression, resulting in increased beta3 and decreased FXYD2 at the protein and messenger RNA (mRNA) levels. Na, K-ATPase isoform alterations may modulate uterine contractility during labor.
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Affiliation(s)
- Rachel V Floyd
- Department of Physiology, School of Biomedical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
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Distribution, expression and functional effects of small conductance Ca-activated potassium (SK) channels in rat myometrium. Cell Calcium 2009; 47:47-54. [PMID: 19969350 DOI: 10.1016/j.ceca.2009.11.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 11/05/2009] [Indexed: 11/21/2022]
Abstract
Calcium-activated potassium channels are important in a variety of smooth muscles, contributing to excitability and contractility. In the myometrium previous work has focussed on the large conductance channels (BK), and the role of small conductance channels (SK) has received scant attention, despite the finding that over-expression of an SK channel isoform (SK3) results in uterine dysfunction and delayed parturition. This study therefore characterises the expression of the three SK channel isoforms (SK1-3) in rat myometrium throughout pregnancy and investigates their effect on cytosolic [Ca] and force and compares this with that of BK channels. Consistent expression of all SK isoform transcripts and clear immunostaining of SK1-3 was found. Inhibition of SK1-3 channels (apamin, scyllatoxin) significantly inhibited outward current, caused membrane depolarisation and elicited action potentials in previously quiescent cells. Apamin or scyllatoxin increased the amplitude of [Ca] and force in spontaneously contracting myometrial strips throughout gestation. The functional effect of SK inhibition was larger than that of BK channel inhibition. Thus we show for the first time that SK1-3 channels are expressed and translated throughout pregnancy and contribute to outward current, regulate membrane potential and hence Ca signals in pregnant rat myometrium. They contribute more to quiescence that BK channels.
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Morphology, Calcium Signaling and Mechanical Activity in Human Ureter. J Urol 2008; 180:398-405. [DOI: 10.1016/j.juro.2008.02.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Indexed: 11/18/2022]
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Aquaporin expression in the human intervertebral disc. J Mol Histol 2008; 39:303-9. [DOI: 10.1007/s10735-008-9166-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 01/22/2008] [Indexed: 12/22/2022]
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