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Heyman SN, Abassi Z, Rosenberger C, Yaseen H, Skarjinski G, Shina A, Mathia S, Krits N, Khamaisi M. Cyclosporine A induces endothelin-converting enzyme-1: Studies in vivo and in vitro. Acta Physiol (Oxf) 2018; 223:e13033. [PMID: 29330945 DOI: 10.1111/apha.13033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 01/04/2018] [Accepted: 01/08/2018] [Indexed: 11/27/2022]
Abstract
AIM Cyclosporine A (CsA) induces renal vasoconstriction and hypoxia and enhances the expression of endothelin-1 (ET-1) pro-hormone (pre-pro-ET-1), plausibly leading to a feed-forward loop of renal vasoconstriction, hypoxia and enhanced synthesis of the potent vasoconstrictor ET-1. Endothelin-converting enzyme (ECE)-1 cleaves big endothelin to generate endothelin (ET)-1 and is upregulated by hypoxia via hypoxia-inducible factor (HIF). We hypothesized that in addition to the direct induction of ET-1 synthesis, CsA might also intensify renal ECE-1 expression, thus contributing to enhanced ET-1 synthesis following CsA. METHODS CsA was administered to Sprague Dawley rats (120 mg/kg/SC) for 4 days, and renal HIF and ECE-1 expression were assessed with Western blots and immunostaining. Human umbilical vein endothelial cells (HUVEC) and proximal tubular cell line (HK-2) were subjected to CsA, and ECE-1 induction was evaluated using real-time mRNA PCR and Western blots. RESULTS Cyclosporine A intensified renal parenchymal ECE-1 expression in the rat kidney, particularly in distal nephron segments, along with renal hypoxia (detected by pimonidazole adducts) and HIF expression, in line with our recent observations showing episodic hypoxia in mice subjected to CsA. Furthermore, in cultured normoxic HUVEC and HK-2 cells, CsA dose-dependently induced both pre-pro-ET-1 and ECE-1 mRNA and protein expression, with enhanced ET-1 generation. CONCLUSION CsA induces ECE-1 via both hypoxic and non-hypoxic pathways. ECE-1 may contribute to increased renal ET-1 generation following CsA, participating in a feed-forward loop of renal parenchymal hypoxia and ET synthesis.
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Affiliation(s)
- S. N. Heyman
- Department of Medicine; Hadassah Hebrew University Hospital; Jerusalem Israel
| | - Z. Abassi
- Department of Physiology, Ruth and Bruce Rappaport Faculty of Medicine; Technion-IIT; Haifa Israel
- Department of Laboratory Medicine; Rambam Health Care Campus; Haifa Israel
| | - C. Rosenberger
- Department of Nephrology and Medical Intensive Care; Charité - Universitätsmedizin; Berlin Germany
| | - H. Yaseen
- Department of Medicine D; Rambam Health Care Campus; Haifa Israel
- Ruth and Bruce Rappaport Faculty of Medicine; Technion-IIT; Haifa Israel
| | - G. Skarjinski
- Department of Medicine; Hadassah Hebrew University Hospital; Jerusalem Israel
| | - A. Shina
- Department of Medicine; Hadassah Hebrew University Hospital; Jerusalem Israel
| | - S. Mathia
- Department of Nephrology and Medical Intensive Care; Charité - Universitätsmedizin; Berlin Germany
| | - N. Krits
- Department of Medicine D; Rambam Health Care Campus; Haifa Israel
- Ruth and Bruce Rappaport Faculty of Medicine; Technion-IIT; Haifa Israel
| | - M. Khamaisi
- Department of Medicine D; Rambam Health Care Campus; Haifa Israel
- Ruth and Bruce Rappaport Faculty of Medicine; Technion-IIT; Haifa Israel
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Itoh K, Izumi Y, Inoue T, Inoue H, Nakayama Y, Uematsu T, Fukuyama T, Yamazaki T, Yasuoka Y, Makino T, Nagaba Y, Tomita K, Kobayashi N, Kawahara K, Mukoyama M, Nonoguchi H. Expression of three isoforms of Na-K-2Cl cotransporter (NKCC2) in the kidney and regulation by dehydration. Biochem Biophys Res Commun 2014; 453:356-61. [PMID: 25265491 DOI: 10.1016/j.bbrc.2014.09.089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 09/19/2014] [Indexed: 10/24/2022]
Abstract
Sodium reabsorption via Na-K-2Cl cotransporter 2 (NKCC2) in the thick ascending limbs has a major role for medullary osmotic gradient and subsequent water reabsorption in the collecting ducts. We investigated intrarenal localization of three isoforms of NKCC2 mRNA expressions and the effects of dehydration on them in rats. To further examine the mechanisms of dehydration, the effects of hyperosmolality on NKCC2 mRNA expression in microdissected renal tubules was studied. RT-PCR and RT-competitive PCR were employed. The expressions of NKCC2a and b mRNA were observed in the cortical thick ascending limbs (CAL) and the distal convoluted tubules (DCT) but not in the medullary thick ascending limbs (MAL), whereas NKCC2f mRNA expression was seen in MAL and CAL. Two-day dehydration did not affect these mRNA expressions. In contrast, hyperosmolality increased NKCC2 mRNA expression in MAL in vitro. Bradykinin dose-dependently decreased NKCC2 mRNA expression in MAL. However, dehydration did not change NKCC2 protein expression in membrane fraction from cortex and outer medulla and in microdissected MAL. These data show that NKCC2a/b and f types are mainly present in CAL and MAL, respectively. Although NKCC2 mRNA expression was stimulated by hyperosmolality in vitro, NKCC2 mRNA and protein expressions were not stimulated by dehydration in vivo. These data suggest the presence of the inhibitory factors for NKCC2 expression in dehydration. Considering the role of NKCC2 for the countercurrent multiplier system, NKCC2f expressed in MAL might be more important than NKCC2a/b.
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Affiliation(s)
- Kazuko Itoh
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Yuichiro Izumi
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Takeaki Inoue
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Hideki Inoue
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Yushi Nakayama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Takayuki Uematsu
- Biomedical Laboratory, Division of Biomedical Research, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan
| | - Takashi Fukuyama
- Biomedical Laboratory, Division of Biomedical Research, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan
| | - Taiga Yamazaki
- Research Center for Medical Environment, Division of Biomedical Research, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan
| | - Yukiko Yasuoka
- Department of Physiology, Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara, Kanagawa 252-0374, Japan
| | - Takeshi Makino
- Department of Nephrology, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan
| | - Yasushi Nagaba
- Department of Nephrology, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan
| | - Kimio Tomita
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Noritada Kobayashi
- Biomedical Laboratory, Division of Biomedical Research, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan
| | - Katsumasa Kawahara
- Department of Physiology, Kitasato University School of Medicine, 1-15-1 Kitasato, Sagamihara, Kanagawa 252-0374, Japan
| | - Masashi Mukoyama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Faculty of Life Sciences, 1.1.1. Honjo, Chuo-ku, Kumamoto, Kumamoto 860-8556, Japan
| | - Hiroshi Nonoguchi
- Department of Internal Medicine and Education & Research Center, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama 364-8501, Japan.
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3
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Erdem ŞR, Emre-Aydıngöz S, Atilla P, Çakar AN, Dalkara T, Bolay H, Tuncer M. Cyclosporine A-induced acute hepatotoxicity in guinea pigs is associated with endothelin-mediated decrease in local hepatic blood flow. Life Sci 2011; 88:753-60. [DOI: 10.1016/j.lfs.2011.02.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 01/13/2011] [Accepted: 02/03/2011] [Indexed: 10/18/2022]
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4
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Memetimin H, Izumi Y, Nakayama Y, Kohda Y, Inoue H, Nonoguchi H, Tomita K. Low pH stimulates vasopressin V2 receptor promoter activity and enhances downregulation induced by V1a receptor stimulation. Am J Physiol Renal Physiol 2009; 297:F620-8. [PMID: 19587140 DOI: 10.1152/ajprenal.90520.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Arginine vasopressin (AVP) plays a key role in the urine concentration mechanism via the vasopressin V2 receptor (V2R) and aquaporin 2 (AQP2) in the kidney. It is well known that V2R is localized on the basolateral side and the V1a receptor (V1aR) is distributed on the luminal side of the collecting ducts. Previously, we reported an increase of V1aR mRNA and a decrease of V2R mRNA in the collecting ducts under chronic metabolic acidosis. However, the regulatory mechanism of V2R in acidic conditions has not yet been determined. In the present study, we investigated the effect of changes in pH on V2R promoter activity, using the LLC-PK(1) cell line stably expressing rat V1aR (LLC-PK(1)/rV1aR). The rV2R promoter activity was significantly increased at 12 h after the incubation in low-pH conditions, which was sustained for 24 h. mRNA and protein expressions of V2R were also increased in low-pH conditions. V1aR stimulation suppressed rV2R promoter activity in a pH-dependent manner. PKA and JNK inhibitors suppressed rV2R promoter activity in both neutral and low-pH conditions without FBS. However, a JNK inhibitor prevented the increase of V2R promoter activity only in low-pH conditions in the presence of FBS. In summary, V2R expression is increased at transcriptional, mRNA, and protein levels in LLC-PK(1)/rV1aR cells under low-pH conditions. Acidic condition-induced V2R enhancement was suppressed by V1aR stimulation, suggesting the crucial role of V1aR in water and electrolyte homeostasis in acidosis.
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Affiliation(s)
- Hasiyet Memetimin
- Dept. of Nephrology, Graduate School of Medical Sciences, Kumamoto Univ., 1-1-1 Honjo, Kumamoto, Kumamoto 860-8556, Japan
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5
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Wakamatsu S, Nonoguchi H, Ikebe M, Machida K, Izumi Y, Memetimin H, Nakayama Y, Nakanishi T, Kohda Y, Tomita K. Vasopressin and hyperosmolality regulate NKCC1 expression in rat OMCD. Hypertens Res 2009; 32:481-7. [PMID: 19390537 DOI: 10.1038/hr.2009.52] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Secretory-type Na-K-2Cl cotransporter (NKCC1) is known to play roles in both acid and sodium excretion, and is more abundant in dehydration. To determine the mechanisms by which dehydration stimulates NKCC1 expression, the effects of vasopressin, oxytocin and hyperosmolality on NKCC1 mRNA and protein expressions in the outer medullary collecting duct (OMCD) of rats were investigated using RT-competitive PCR and western blot analysis. Microdissected OMCD was incubated in isotonic or hypertonic solution, or with AVP or oxytocin for 60 min at 37 degrees C. Hyperosmolality induced by NaCl, mannitol or raffinose increased NKCC1 mRNA expression in OMCD by 130-240% in vitro. The stimulation of NKCC1 mRNA expression by NaCl was highest at 690 mosmol kg(-1) H(2)O and gradually decreased at higher osmolalities. The incubation of OMCD with AVP (10(-7) M) for 60 min increased NKCC1 mRNA expression by 100%. The administration of AVP to rats for 4 days using an osmotic mini-pump also increased NKCC1 mRNA and protein expressions in OMCD by 130%. In contrast, oxytocin (10(-7) M) did not stimulate the NKCC1 mRNA expression in OMCD in vitro. Chronic injection of oxytocin increased the NKCC1 mRNA expression by 36%. These data showed that hyperosmolality and vasopressin stimulate NKCC1 mRNA and protein expressions in rat OMCD. It is concluded that NKCC1 expression is regulated directly and indirectly by vasopressin.
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Affiliation(s)
- Shiho Wakamatsu
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Honjo, Kumamoto, Japan
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6
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Acute and chronic metabolic acidosis interferes with aquaporin-2 translocation in the rat kidney collecting ducts. Hypertens Res 2009; 32:358-63. [DOI: 10.1038/hr.2009.19] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Goettsch W, Schubert A, Morawietz H. Expression of human endothelin-converting enzyme isoforms: role of angiotensin II. Can J Physiol Pharmacol 2008; 86:299-309. [PMID: 18516092 DOI: 10.1139/y08-023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A key step in endothelin-1 (ET-1) synthesis is the proteolytic cleavage of big ET-1 by the endothelin-converting enzyme-1 (ECE-1). Four alternatively spliced isoforms, ECE-1a to ECE-1d, have been discovered; however, regulation of the expression of specific ECE-1 isoforms is not well understood. Therefore, we stimulated primary human umbilical vein endothelial cells (HUVECs) with angiotensin II (Ang II). Furthermore, expression of ECE-1 isoforms was determined in internal mammary arteries of patients undergoing coronary artery bypass grafting surgery. Patients had received one of 4 therapies: angiotensin-converting enzyme inhibitors (ACE-I), Ang II type 1 receptor blockers (ARB), HMG-CoA reductase inhibitors (statins), and a control group that had received neither ACE-I, ARB (that is, treatment not interfering in the renin-angiotensin system), nor statins. Under control conditions, ECE-1a is the dominant isoform in HUVECs (4.5+/-2.8 amol/microg RNA), followed by ECE-1c (2.7+/-1.0 amol/microg), ECE-1d (0.49+/-0.17 amol/microg), and ECE-1b (0.17+/-0.04 amol/microg). Stimulation with Ang II did not change the ECE-1 expression pattern or the ET-1 release. We found that ECE-1 mRNA expression was higher in patients treated with statins than in patients treated with ARB therapy (5.8+/-0.76 RU versus 3.0+/-0.4 RU), mainly attributed to ECE-1a. In addition, ECE-1a mRNA expression was higher in patients receiving ACE-I therapy than in patients receiving ARB therapy (1.68+/-0.27 RU versus 0.83+/-0.07 RU). We conclude that ECE-1a is the major ECE-1 isoform in primary human endothelial cells. Its expression in internal mammary arteries can be regulated by statin therapy and differs between patients with ACE-I and ARB therapy.
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Affiliation(s)
- W Goettsch
- Department of Vascular Endothelium and Microcirculation, Medical Clinic and Policlinic III, University of Technology Dresden, Fetscherstr. 74, D-01307 Dresden, Germany
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8
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Khamaisi M, Raz I, Shilo V, Shina A, Rosenberger C, Dahan R, Abassi Z, Meidan R, Lecht S, Heyman S. Diabetes and radiocontrast media increase endothelin converting enzyme-1 in the kidney. Kidney Int 2008; 74:91-100. [DOI: 10.1038/ki.2008.112] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Smith CP, Fenton RA. Genomic organization of the mammalian SLC14a2 urea transporter genes. J Membr Biol 2007; 212:109-17. [PMID: 17264986 DOI: 10.1007/s00232-006-0870-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2006] [Indexed: 11/28/2022]
Abstract
Urea transporters encoded by the UT-A gene play fundamental roles in the kidney and possibly other tissues. Knowledge of the genomic organization of the mouse, rat and human UT-A genes has enabled the engineering of transgenic and knockout animals and these have helped refine our understanding of the role of UT-A proteins. This review summarizes the published work that has accrued on the structure and regulation of these genes. It also documents a novel cDNA, human UT-A3, which has enabled a major refinement of the human UT-A gene structure. This and other information contained in this review should prove useful for future comparative genomic analysis, studies addressing gene regulation and for the engineering of transgenic and knockout animal strains.
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Affiliation(s)
- C P Smith
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9NT, UK.
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10
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Izumi Y, Nakayama Y, Mori T, Miyazaki H, Inoue H, Kohda Y, Inoue T, Nonoguchi H, Tomita K. Downregulation of vasopressin V2 receptor promoter activity via V1a receptor pathway. Am J Physiol Renal Physiol 2007; 292:F1418-26. [PMID: 17213462 DOI: 10.1152/ajprenal.00358.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vasopressin V(1a) and V(2) receptors (V(1a)R and V(2)R, respectively) distribute in the collecting duct of the kidney. Although the function of V(2)R mediating the antidiuretic effect of AVP has been investigated in detail, the role of V(1a)R in the collecting ducts has not been elucidated. In the present study, we have investigated the role of the V(1a)R pathway in V(2)R promoter activity. We cloned the 5'-flanking region of rat V(2)R (rV(2)R) and investigated rV(2)R promoter activity in the LLC-PK(1) cell line transfected to express rat V(1a)R (rV(1a)R) dominantly (LLC-PK(1)/rV(1a)R). AVP induced a transient increase, followed by a sustained decrease, of rV(2)R promoter activity in these cells. This AVP-induced decrease of rV(2)R promoter activity was inhibited by V(1a)R, but not V(2)R, antagonist. PMA mimicked this decrease of rV(2)R promoter activity. On the contrary, 8-(4-chlorophenylthio)-cAMP increased rV(2)R promoter activity. These PMA- and 8-(4-chlorophenylthio)-cAMP-induced effects were not observed on the deletion segment of the 5'-flanking region lacking CAAT and SP1 sites. In conclusion, 1) expression of the V(2)R is downregulated via the V(1a)R pathway in LLC-PK(1)/rV(1a)R cells, and 2) expression of the V(2)R is downregulated by the PMA-induced PKC pathway and upregulated by the cAMP-PKA pathway. These opposite effects of PKC and PKA appear to be regulated by the same promoter region of CAAT and SP1.
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Affiliation(s)
- Yuichiro Izumi
- Department of Nephrology, Graduate School of Medical Sciences, Kumamoto University, Kunamoto, Japan.
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11
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Machida K, Wakamatsu S, Izumi Y, Yosifovska T, Matsuzaki T, Nakayama Y, Kohda Y, Inoue T, Saito H, Tomita K, Nonoguchi H. Downregulation of the V2 vasopressin receptor in dehydration: mechanisms and role of renal prostaglandin synthesis. Am J Physiol Renal Physiol 2006; 292:F1274-82. [PMID: 17190913 DOI: 10.1152/ajprenal.00154.2006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vasopressin-aquaporin 2 system plays a key role in urine concentration in dehydration. In contrast to the upregulation of aquaporin 2, the downregulation of the vasopressin V2 receptor in dehydration is known. We investigated the mechanisms of this downregulation in dehydration using reverse transcription-competitive polymerase chain reaction (RT-competitive PCR) and Western blot analysis. The incubation of microdissected inner medullary collecting ducts (IMCDs) in a hypertonic medium or with vasopressin stimulated V2 receptor mRNA and protein expression, showing that dehydration-induced hyperosmolality in renal medulla and increased plasma arginine vasopressin (AVP) concentration should upregulate V2 receptor. The presence of inhibitory factors on the V2 receptor in dehydration was suggested. Prostaglandin E(2) (PGE(2)) is known to inhibit AVP-induced cAMP production and to increase production in dehydration. PGE(2) slightly stimulated V2 receptor mRNA expression in IMCD in vitro. However, PGE(2) inhibited V2 receptor mRNA expression in IMCD in the presence of 10(-9) M vasopressin. The blockade of PGE(2) synthesis by indomethacin in dehydrated rats increased V2 receptor protein expression after 24-48 h with an early increase in V2 receptor mRNA expression. In summary, these data suggest that increased production of PGE(2) in renal medulla plays a key role in the downregulation of V2 receptor in dehydration.
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Affiliation(s)
- Kenji Machida
- Dept. of Nephrology, Kumamoto Univ. Graduate School of Medical Sciences, Kumamoto, Kumamoto 860-8556, Japan
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12
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Machida K, Nonoguchi H, Wakamatsu S, Inoue H, Yosifovska T, Inoue T, Tomita K. Acute regulation of the epithelial sodium channel gene by vasopressin and hyperosmolality. Hypertens Res 2004; 26:629-34. [PMID: 14567502 DOI: 10.1291/hypres.26.629] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The amiloride-sensitive epithelial sodium channel (ENaC) plays a key role in sodium reabsorption in the collecting ducts. We examined ENaC mRNA distribution along the nephron and acute effects of vasopressin and hyperosmolality on ENaC mRNA expression. ENaCalpha, beta, and gamma mRNA expressions were observed in cortical, outer medullary and initial inner medullary collecting ducts (CCD, OMCD and ilMCD, respectively). ENaCalpha mRNA expression was also observed in medullary and cortical thick ascending limbs (MAL and CAL, respectively), while ENaCbeta and gamma mRNA expressions were not observed. Furthermore, ENaCalpha mRNA expression in MAL but not in collecting ducts was stimulated by acute exposure to arginine vasopressin (AVP), 8-(4-chlorophenylthio) (CPT)-cAMP and hyperosmolality. However, the physiological significance of these effects is not known, since ENaC protein is reported to be absent in MAL. These data suggest that ENaCalpha mRNA expression in MAL but not in collecting ducts is acutely regulated by AVP and hyperosmolality. The absence of stimulation of ENaCalpha mRNA expression in collecting ducts suggests the physiological significance of ENaCbeta and gamma mRNA for acute regulation by vasopressin. Determining the physiological significance of the acute effect of vasopressin in MAL will require further investigations.
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Affiliation(s)
- Kenji Machida
- Department of Nephrology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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Imanishi K, Nonoguchi H, Nakayama Y, Machida K, Ikebe M, Tomita K. Type 1A angiotensin II receptor is regulated differently in proximal and distal nephron segments. Hypertens Res 2003; 26:405-11. [PMID: 12887132 DOI: 10.1291/hypres.26.405] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Angiotensin II plays important roles in renal vasoconstriction, sodium reabsorption in proximal tubules, and cell proliferation. Angiotensin II receptors are present not only in proximal but also in distal tubules. We investigated the effects of dehydration on the mRNA expression of type 1A angiotensin II receptor (AT1A) in proximal and distal nephron segments and on the expression of type 1 angiotensin II receptor (AT1) protein. Competitive polymerase chain reaction was employed to quantitatively examine mRNA expression, and AT1-specific polyclonal antibody was used for Western blot analysis. AT1A mRNA expression was most abundant in glomeruli. Collecting ducts showed higher expressions than did proximal tubules or thick ascending limbs. Dehydration caused an increase of AT1A mRNA expression in glomeruli, proximal straight tubules (PST), and medullary and cortical thick ascending limbs (MAL and CAL, respectively). In contrast, dehydration decreased AT1A mRNA expression in cortical, outer medullary, and inner medullary collecting ducts (CCD, OMCD, and IMCD, respectively). Incubation of isolated glomeruli, PST, and IMCD in hypertonic solution made by NaCl and mannitol in vitro increased AT1A mRNA expression. Incubation of IMCD with AVP (10(-7) mol/l) also increased AT1A mRNA expression. AT1 was detected at 45 kDa by Western blotting. Dehydration caused a decrease and increase of AT1 expression in the cortex and the medulla, respectively. In summary, these data showed that the mechanisms of the regulation of AT1A differ between proximal and distal tubules. The finding that AT1 was up-regulated in the medulla during dehydration may suggest that this receptor plays an important role in dehydration in the distal tubules.
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Affiliation(s)
- Ken Imanishi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
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14
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Shiraishi N, Kitamura K, Kohda Y, Narikiyo T, Adachi M, Miyoshi T, Iwashita K, Nonoguchi H, Miller RT, Tomita K. Increased endothelin-1 expression in the kidney in hypercalcemic rats. Kidney Int 2003; 63:845-52. [PMID: 12631065 DOI: 10.1046/j.1523-1755.2003.00801.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Although hypercalcemia causes diuresis and natriuresis, the molecular mechanisms of these effects are not well established. Recently, the important role of the calcium-sensing receptor (CaR) in hypercalcemia-induced polyuria was reported. Endothelin-1 (ET-1) that is locally produced in the nephron has been suggested to have the natriuretic and/or diuretic effects in the kidney. Therefore, we hypothesized that ET-1 expression could be increased through the activation of CaR in the kidney in hypercalcemia. METHODS Rats were made hypercalcemic by dihydrotachysterol (DHT) treatment. The urinary concentration of ET-1 and the mRNA expression of ET-1 in the kidney were determined. Immunohistochemistry was performed to determine types of the cells that produce ET-1. CaR and ET-1 promoter luciferase constructs were co-expressed in COS-7 cells and the ET-1 promoter activity following the addition of extracellular calcium was measured by the luciferase assay. RESULTS In hypercalcemic rat, urinary ET-1 excretion was increased by twofold, and ET-1 mRNA expression was increased in the kidney cortex by threefold. In cortical collecting duct (CCD), both principal cells and intercalated cells synthesized ET-1. In cells that express CaR, ET-1 promoter was activated in a dose-dependent manner by extracellular calcium over the range of 0.5 to 3.0 mmol/L. CONCLUSIONS First, activation of CaR increases ET-1 transcription in a dose-dependent manner. Second, hypercalcemia increases ET-1 production in the kidney cortex. These data suggest the possibility that CaR might play an important role in hypercalcemia-induced increase in ET-1 production.
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Affiliation(s)
- Naoki Shiraishi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Kumamoto, Japan
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Kikuchi Y, Nonoguchi H, Machida K, Wakamatsu S, Koga H, Tomita K. Regulation of the apoptosis-related genes, Bax and Bcl-2, in the early stage of diabetes mellitus. Nephrology (Carlton) 2002. [DOI: 10.1046/j.1440-1797.2002.00127.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Adachi M, Kitamura K, Miyoshi T, Narikiyo T, Iwashita K, Shiraishi N, Nonoguchi H, Tomita K. Activation of epithelial sodium channels by prostasin in Xenopus oocytes. J Am Soc Nephrol 2001; 12:1114-1121. [PMID: 11373334 DOI: 10.1681/asn.v1261114] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Prostasin, a novel serine protease, was purified from seminal fluid, and its cDNA sequence was determined. Expression of prostasin was detected in human tissues, including prostate, kidney, and lung, as well as bodily fluids, including seminal fluid and urine. However, its physiologic role in the human body is not known. Recently, a novel regulatory mechanism by which serine proteases activate epithelial sodium channel in the Xenopus oocyte was identified. Therefore, it was hypothesized that prostasin could activate sodium currents, and a rat prostasin cDNA clone was isolated to investigate its physiologic function. Rat prostasin mRNA is expressed predominantly in kidney, and lower levels of expression were detected in prostate, lung, colon, stomach, and skin. These all are epithelial tissues in which the epithelial sodium channel (ENaC) is expressed. Coexpression of rat prostasin and rat ENaC in Xenopus oocytes increased the amiloride-sensitive sodium current by twofold. Preincubation of oocytes that expressed prostasin with aprotinin did not result in an increase in sodium current, compared with the control. The removal of aprotinin from the bath solution resulted in a twofold increase of the current only in oocytes that expressed prostasin, which indicates that protease activity of prostasin is required for the ENaC activation. Expression of rat prostasin had no effect on the potassium current when expressed with rat renal outer medulla K channel, which shows specificity of prostasin action for ENAC: These results indicate that prostasin acts as an extracellular regulator of ENAC:
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Affiliation(s)
- Masataka Adachi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Kenichiro Kitamura
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Taku Miyoshi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Takefumi Narikiyo
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Kozo Iwashita
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Naoki Shiraishi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Hiroshi Nonoguchi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Kimio Tomita
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
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Capodicasa E, Tassi C, Rossi R, Biondi R. Plasma endothelin-1 and big endothelin-1 levels in superior and inferior vena cava during protracted antiorthostatic hypokinetic/hypodynamia in rats. Clin Chem Lab Med 2001; 39:509-13. [PMID: 11506463 DOI: 10.1515/cclm.2001.085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The plasma levels of endothelin-1 and big endothelin-1 were evaluated in blood of rats in the superior and inferior vena cava, in normal posture (synchronous controls), and after 12 days head-down suspension and 1 day recovery in normal posture. In synchronous controls, the mean plasma concentration of endothelin-1 in inferior vena cava or superior vena cava was almost the same (5.89+/-0.63 pmol/l and 5.67+/-0.64 pmol/l, respectively), whereas the mean plasma concentration of big endothelin-1 was higher (p<0.05) in superior vena cava compared to inferior vena cava (5.49+/-0.75 pmol/l and 1.39+/-0.15 pmol/l, respectively). In samples from superior vena cava of head-down suspended rats big endothelin-1 levels were significantly lower (p<0.05) up to day 9 of suspension, compared to non-suspended synchronous controls, whereas endothelin-1 values were higher (p<0.05). Big endothelin-1 concentration was higher (p<0.05) in inferior vena cava compared to non-suspended synchronous controls. The behaviour of endothelin-1 was more complex, endothelin-1 levels were lower (p<0.05) on day 1 of head-down suspension and higher (p<0.05) in samples taken on days 9 and 12. After 1 day recovery endothelin-1 and big endothelin-1 concentrations returned to normal in both superior vena cava and inferior vena cava. These data indicate that the endothelial system involvement for the two venous beds is different and suggest that local rather than systemic evaluation could better explain endothelial involvement and the contribution of different anatomic sites to the biosynthesis, conversion and clearance of the various involved molecules.
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Affiliation(s)
- E Capodicasa
- Dipartimento di Medicina Clinica e Sperimentale, Università degli Studi di Perugia, Policlinico Monteluce, Italy
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Ikebe M, Nonoguchi H, Nakayama Y, Tashima Y, Tomita K. Upregulation of the secretory-type Na(+)/K(+)/2Cl(-)-cotransporter in the kidney by metabolic acidosis and dehydration in rats. J Am Soc Nephrol 2001; 12:423-430. [PMID: 11181789 DOI: 10.1681/asn.v123423] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The functional role and mechanisms of regulation of the Na(+)/K(+)/2Cl(-)-cotransporter NKCC1 in the kidney have not yet been clarified. NKCC1 mRNA and protein expression in control rats, rats with dehydration (2 d), and rats with metabolic acidosis (NH(4)Cl in the food for 6 to 7 d) was examined using reverse transcription-PCR and Western blotting. In contrast to the abundant NKCC1 mRNA expression in the terminal inner medullary collecting ducts in mice, expression was found to be most abundant in the outer medullary collecting ducts (OMCD) in rats. Dehydration and metabolic acidosis increased NKCC1 mRNA expression three- to fivefold not only in the OMCD but also in the cortical collecting ducts and inner medullary collecting ducts. Dehydration and metabolic acidosis increased NKCC1 protein expression twofold in the membrane fraction from the outer medulla. NKCC1 protein expression was observed not in the microdissected medullary thick ascending limbs but in the OMCD, and it was stimulated twofold by dehydration and metabolic acidosis. Incubation of OMCD in low-pH medium increased NKCC1 mRNA expression. In summary, NKCC1 mRNA and protein expression is upregulated with dehydration and metabolic acidosis. NKCC1 may play an important role in adaptation to these physiologic conditions. Low pH and possibly hypertonicity stimulate NKCC1 mRNA expression in OMCD.
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Affiliation(s)
- Mika Ikebe
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Hiroshi Nonoguchi
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Yushi Nakayama
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Yuka Tashima
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
| | - Kimio Tomita
- Third Department of Internal Medicine, Kumamoto University School of Medicine, Kumamoto, Japan
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Affiliation(s)
- A Benigni
- Istituto di Ricerche Farmacologiche Mario Negri, Bergamo, Italy
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