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Ilatovskaya DV, Levchenko V, Winsor K, Blass GR, Spires DR, Sarsenova E, Polina I, Zietara A, Paterson M, Kriegel AJ, Staruschenko A. Effects of elevation of ANP and its deficiency on cardiorenal function. JCI Insight 2022; 7:148682. [PMID: 35380994 PMCID: PMC9090260 DOI: 10.1172/jci.insight.148682] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/30/2022] [Indexed: 11/17/2022] Open
Abstract
Atrial natriuretic peptide (ANP), encoded by Nppa, is a vasodilatory hormone that promotes salt excretion. Genome-wide association studies identified Nppa as a causative factor of blood pressure development, and in humans, ANP levels were suggested as an indicator of salt sensitivity. This study aimed to provide insights into the effects of ANP on cardiorenal function in salt-sensitive hypertension. To address this question, hypertension was induced in SSNPPA-/- (knockout of Nppa in the Dahl Salt-Sensitive (SS) rat background) or SSWT (wild type Dahl SS) rats by a high salt diet challenge (HS, 4% NaCl for 21 days). Chronic infusion of ANP in SSWT rats attenuated the increase in blood pressure and cardiorenal damage. Overall, SSNPPA-/- strain demonstrated higher blood pressure and intensified cardiac fibrosis (with no changes in ejection fraction) compared to SSWT rats. Furthermore, SSNPPA-/- rats exhibited kidney hypertrophy and higher glomerular injury scores, reduced diuresis, and lower sodium and chloride excretion than SSWT when fed a HS diet. Additionally, the activity of epithelial Na+ channel (ENaC) was found to be increased in the collecting ducts of the SSNPPA-/- rats. Taken together, these data show promise for the therapeutic benefits of ANP and ANP-increasing drugs for treating salt-sensitive hypertension.
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Affiliation(s)
- Daria V Ilatovskaya
- Department of Physiology, Medical College of Georgia, Augusta, United States of America
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States of America
| | - Kristen Winsor
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States of America
| | - Gregory R Blass
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States of America
| | - Denisha R Spires
- Department of Physiology, Medical College of Georgia, Augusta, United States of America
| | - Elizaveta Sarsenova
- Department of Medicine, Medical University of South Carolina, Charleston, United States of America
| | - Iuliia Polina
- Department of Medicine, Medical University of South Carolina, Charleston, United States of America
| | - Adrian Zietara
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States of America
| | - Mark Paterson
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States of America
| | - Alison J Kriegel
- Department of Physiology, Medical College of Wisconsin, Milwaukee, United States of America
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2
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Haramura T, Ikegami T, Wong MKS, Takei Y. Preparatory Mechanisms for Salinity Tolerance in Two Congeneric Anuran Species Inhabiting Distinct Osmotic Habitats. Zoolog Sci 2019; 36:215-222. [PMID: 31251490 DOI: 10.2108/zs180091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 12/04/2018] [Indexed: 11/17/2022]
Abstract
Anurans occupy a wide variety of habitats of diverse salinities, and their osmoregulatory ability is strongly regulated by hormones. In this study, we compared the adaptability and hormonal responses to osmotic stress between two kajika frogs, Buergeria japonica (B.j.) and B. buergeri, (B.b.), which inhabit coastal brackish waters (BW) in the Ryukyu Islands and freshwater (FW) in the Honshu, respectively. Both hematocrit and plasma Na+ concentration were significantly higher in B.j. than in B.b. when both were kept in FW. After transfer to one-third seawater (simulating the natural BW environment), which is slightly hypertonic to their body fluids, their body mass decreased and plasma Na concentration increased significantly in both species. After transfer, plasma Na+ concentration increased significantly in both species. We examined the gene expression of two major osmoregulatory hormones, arginine vasotocin (AVT) and atrial natriuretic peptide (ANP), after partial cloning of their cDNAs. ANP mRNA levels were more than 10-fold higher in B.j. than in B.b. in FW, but no significant difference was observed for AVT mRNA levels due to high variability, although the mean value of B.j. was twice that of B.b. Both AVT and ANP mRNA levels increased significantly after transfer to BW in B.b. but not in B.j., probably because of the high levels in FW. These results suggest that B.j. maintains high plasma Na+ concentration and anp gene expression to prepare for the future encounter of the high salinity. The unique preparatory mechanism may allow B.j. wide distribution in oceanic islands.
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Affiliation(s)
- Takashi Haramura
- The Hakubi Center for Advanced Research, Kyoto University, Sakyo, Kyoto 606-8501, Japan,
| | - Taro Ikegami
- Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Marty K S Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
| | - Yoshio Takei
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan
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Ji HL, Nie HG, Chang Y, Lian Q, Liu SL. CPT-cGMP Is A New Ligand of Epithelial Sodium Channels. Int J Biol Sci 2016; 12:359-66. [PMID: 27019621 PMCID: PMC4807156 DOI: 10.7150/ijbs.13764] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/11/2015] [Indexed: 12/28/2022] Open
Abstract
Epithelial sodium channels (ENaC) are localized at the apical membrane of the epithelium, and are responsible for salt and fluid reabsorption. Renal ENaC takes up salt, thereby controlling salt content in serum. Loss-of-function ENaC mutations lead to low blood pressure due to salt-wasting, while gain-of-function mutations cause impaired sodium excretion and subsequent hypertension as well as hypokalemia. ENaC activity is regulated by intracellular and extracellular signals, including hormones, neurotransmitters, protein kinases, and small compounds. Cyclic nucleotides are broadly involved in stimulating protein kinase A and protein kinase G signaling pathways, and, surprisingly, also appear to have a role in regulating ENaC. Increasing evidence suggests that the cGMP analog, CPT-cGMP, activates αβγ-ENaC activity reversibly through an extracellular pathway in a dose-dependent manner. Furthermore, the parachlorophenylthio moiety and ribose 2'-hydroxy group of CPT-cGMP are essential for facilitating the opening of ENaC channels by this compound. Serving as an extracellular ligand, CPT-cGMP eliminates sodium self-inhibition, which is a novel mechanism for stimulating salt reabsorption in parallel to the traditional NO/cGMP/PKG signal pathway. In conclusion, ENaC may be a druggable target for CPT-cGMP, leading to treatments for kidney malfunctions in salt reabsorption.
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Affiliation(s)
- Hong-Long Ji
- 1. Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas 75708, USA
| | - Hong-Guang Nie
- 2. Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang 110001, China
| | - Yongchang Chang
- 3. Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, Arizona, 85013, USA
| | - Qizhou Lian
- 4. Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Shan-Lu Liu
- 5. Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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Xu X, Lai R. The chemistry and biological activities of peptides from amphibian skin secretions. Chem Rev 2015; 115:1760-846. [PMID: 25594509 DOI: 10.1021/cr4006704] [Citation(s) in RCA: 235] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Xueqing Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology , Kunming 650223, Yunnan, China
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Guo LJ, Alli AA, Eaton DC, Bao HF. ENaC is regulated by natriuretic peptide receptor-dependent cGMP signaling. Am J Physiol Renal Physiol 2013; 304:F930-7. [PMID: 23324181 DOI: 10.1152/ajprenal.00638.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Epithelial sodium channels (ENaCs) located at the apical membrane of polarized epithelial cells are regulated by the second messenger guanosine 3',5'-cyclic monophosphate (cGMP). The mechanism for this regulation has not been completely characterized. Guanylyl cyclases synthesize cGMP in response to various intracellular and extracellular signals. We investigated the regulation of ENaC activity by natriuretic peptide-dependent activation of guanylyl cyclases in Xenopus 2F3 cells. Confocal microscopy studies show natriuretic peptide receptors (NPRs), including those coupled to guanylyl cyclases, are expressed at the apical membrane of 2F3 cells. Single-channel patch-clamp studies using 2F3 cells revealed that atrial natriuretic peptide (ANP) or 8-(4-chlorophenylthio)-cGMP, but not C-type natriuretic peptide or cANP, decreased the open probability of ENaC. This suggests that NPR-A, but not NPR-B or NPR-C, is involved in the natriuretic peptide-mediated regulation of ENaC activity. Also, it is likely that a signaling pathway involving cGMP and nitric oxide (NO) are involved in this mechanism, since inhibitors of soluble guanylyl cyclase, protein kinase G, inducible NO synthase, or an NO scavenger blocked or reduced the effect of ANP on ENaC activity.
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Affiliation(s)
- Lai-Jing Guo
- Department of Physiology, Emory University School of Medicine and the Center for Cell and Molecular Signaling, Atlanta, GA 30322, USA
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Han DY, Nie HG, Su XF, Shi XM, Bhattarai D, Zhao M, Zhao RZ, Landers K, Tang H, Zhang L, Ji HL. 8-(4-chlorophenylthio)-guanosine-3',5'-cyclic monophosphate-Na stimulates human alveolar fluid clearance by releasing external Na+ self-inhibition of epithelial Na+ channels. Am J Respir Cell Mol Biol 2011; 45:1007-14. [PMID: 21562313 DOI: 10.1165/rcmb.2011-0004oc] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Salt absorption via alveolar epithelial Na(+) channels (ENaC) is a critical step for maintaining an airspace free of flooding. Previously, we found that 8-(4-chlorophenylthio)-guanosine-3',5'-cyclic monophosphate-Na (CPT-cGMP) activated native and heterologous ENaC. To investigate the potential pharmacological relevance, we applied this compound intratracheally to human lungs and found that ex vivo alveolar fluid clearance was increased significantly. Furthermore, this compound eliminated self-inhibition in human lung H441 cells and in oocytes expressing human αβγ but not δβγ channels. To further elucidate this novel mechanism, we constructed mutants abolishing (β(ΔV348) and γ(H233R)) or augmenting (α(Y458A) and γ(M432G)) self-inhibition. The mutants eliminating self-inhibition lost their responses to CPT-cGMP, whereas those enhancing self-inhibition facilitated the stimulatory effects of this compound. CPT-cGMP was unable to activate a high P(o) mutant (β(S520C)) and plasmin proteolytically cleaved channels. Our data suggest that elimination of self-inhibition of αβγ ENaC may be a novel mechanism for CPT-cGMP to stimulate salt reabsorption in human lungs.
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Affiliation(s)
- Dong-Yun Han
- Department of Biochemistry, University of Texas Health Science Center at Tyler, USA
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Kaiya H, Koizumi Y, Konno N, Yamamoto K, Uchiyama M, Kangawa K, Miyazato M. Ghrelin Receptor in Two Species of Anuran Amphibian, Bullfrog (Rana catesbeiana), and Japanese Tree Frog (Hyla japonica). Front Endocrinol (Lausanne) 2011; 2:31. [PMID: 22654801 PMCID: PMC3356126 DOI: 10.3389/fendo.2011.00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 08/26/2011] [Indexed: 12/28/2022] Open
Abstract
We have identified cDNA encoding a functional growth hormone secretagogue-receptor 1a (GHS-R1a, ghrelin receptor) in two species of anuran amphibian, the bullfrog (Rana catesbeiana), and the Japanese tree frog (Hyla japonica). Deduced receptor protein for bullfrog and Japanese tree frog (tree frog) was comprised of 374- and 371-amino acids, respectively. The two receptors shared 86% identity, and are grouped to the clade of the tetrapod homologs by phylogenetic analysis. In functional analyses, ghrelin and GHS-R1a agonists increased intracellular Ca(2+) concentration in GHS-R1a-transfected-HEK293 cell, but ligand selectivity of ghrelin with Ser(3) and Thr(3) was not observed between the two receptors. Bullfrog GHS-R1a mRNA was mainly expressed in the brain, stomach, and testis. In the brain, the gene expression was detected in the diencephalon and mesencephalon, but not in the pituitary. Tree frog GHS-R1a mRNA was predominantly expressed in the gastrointestinal tract and ovary, but not detected in the pituitary. In bullfrog stomach but not the brain, GHS-R1a mRNA expression increased after 10 days of fasting. For tree frog, GHS-R1a mRNA expression was increased in the brain, stomach and ventral skin by 10 days of fasting, and in the stomach and ventral skin by a dehydration treatment. Intracerebroventricular injection of ghrelin in dehydrated tree frog did not affect water absorption from the ventral skin. These results suggest that ghrelin is involved in energy homeostasis and possibly in osmoregulation in frogs.
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Affiliation(s)
- Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
- *Correspondence: Hiroyuki Kaiya, Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan. e-mail:
| | - Yasushi Koizumi
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Norifumi Konno
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Kazutoshi Yamamoto
- Laboratory of Integrative Brain Science, Department of Biology, Waseda UniversityTokyo, Japan
| | - Minoru Uchiyama
- Department of Biological Science, Graduated School of Science and Engineering, University of ToyamaToyama, Japan
| | - Kenji Kangawa
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
| | - Mikiya Miyazato
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research InstituteSuita, Osaka, Japan
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Nie HG, Zhang W, Han DY, Li QN, Li J, Zhao RZ, Su XF, Peng JB, Ji HL. 8-pCPT-cGMP stimulates alphabetagamma-ENaC activity in oocytes as an external ligand requiring specific nucleotide moieties. Am J Physiol Renal Physiol 2009; 298:F323-34. [PMID: 20007351 DOI: 10.1152/ajprenal.00307.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Epithelial sodium channels (ENaC) are regulated by protein kinase A, in addition to a broad spectrum of other protein kinases. It is not clear whether cGMP/PKG signaling might regulate ENaC activity. We examined the responses of alphabetagamma-ENaC channels expressed in Xenopus oocytes to 8-(4-chlorophenylthio)-cGMP (8-pCPT-cGMP), a cell-permeable cGMP analog. This compound stimulated human alphabetagamma-ENaC activity in a dose-dependent fashion, but cell-impermeable cGMP had no effect. Similar stimulatory effects of cGMP were observed in oocytes expressing either mouse or rat alphabetagamma-ENaC channels. The identical ion selectivity and amiloride sensitivity of the 8-pCPT-cGMP-activated currents to those of alphabetagamma-ENaC channels suggest that the cGMP-activated currents are associated with expressed ENaC. The PKGI activator Sp isomer of beta-phenyl-1,N(2)-etheno-8-bromo-cGMP did not elicit a rise in ENaC current and that the 8-pCPT-cGMP-induced activation of ENaC channels was blocked by incubating oocytes with a PKG inhibitor, but not with other cGMP-sensitive kinase inactivators for PKA, MEK, MAP, and PKC. Surprisingly, both site-directed mutation of putative consensus PKG phosphorylation sites and truncation of entire cytosolic NH(2)- and COOH-terminal tails did not alter the response to 8-pCPT-cGMP. The ENaC activity was activated to the same extent by 8-pCPT-cGMP in cells in which PKGII expression was knocked down using small interfering RNA. Analog to 8-CPT-cAMP, 8-pCPT-cGMP was capable of activating ENaC in the identical manner in cell-free outside-out patches. We conclude that the rapid upregulation of human alphabetagamma-ENaC activity in oocytes by external 8-pCPT-cGMP and 4-chlorothiolphenol-cAMP depends on the para-chlorophenylthiol and the hydroxy groups, and 8-pCPT-cGMP may serve as a novel ENaC ligand in addition to activating PKG signal.
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Affiliation(s)
- Hong-Guang Nie
- Department of Biochemistry, University of Texas Health Science Center at Tyler, Tyler, Texas, USA
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Bhalla V, Hallows KR. Mechanisms of ENaC regulation and clinical implications. J Am Soc Nephrol 2008; 19:1845-54. [PMID: 18753254 DOI: 10.1681/asn.2008020225] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The epithelial Na+ channel (ENaC) transports Na+ across tight epithelia, including the distal nephron. Different paradigms of ENaC regulation include extrinsic and intrinsic factors that affect the expression, single-channel properties, and intracellular trafficking of the channel. In particular, recent discoveries highlight new findings regarding proteolytic processing, ubiquitination, and recycling of the channel. Understanding the regulation of this channel is critical to the understanding of various clinical phenomena, including normal physiology and several diseases of kidney and lung epithelia, such as blood pressure (BP) control, edema, and airway fluid clearance. Significant progress has been achieved in this active field of research. Although ENaC is classically thought to be a mediator of BP and volume status through Na+ reabsorption in the distal nephron, several studies in animal models highlight important roles for ENaC in lung pathophysiology, including in cystic fibrosis. The purpose of this review is to highlight the various modes and mechanisms of ENaC regulation, with a focus on more recent studies and their clinical implications.
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Affiliation(s)
- Vivek Bhalla
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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