1
|
Takei Y, Ando M, Wong MKS, Tsukada T. Molecular mechanisms underlying guanylin-induced transcellular Cl - secretion into the intestinal lumen of seawater-acclimated eels. Gen Comp Endocrinol 2022; 318:113986. [PMID: 35114197 DOI: 10.1016/j.ygcen.2022.113986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 12/20/2021] [Accepted: 01/27/2022] [Indexed: 11/19/2022]
Abstract
Guanylin (GN) stimulates Cl- secretion into the intestinal lumen of seawater-acclimated eels, but the molecular mechanisms of transepithelial Cl- transport are still unknown. In Ussing chamber experiments, we confirmed that mucosal application of eel GN reversed intestinal serosa-negative potential difference, indicating Cl- secretion. Serosal application of DNDS or mucosal application of DPC inhibited the GN effect, but serosal application of bumetanide had no effect. Removal of HCO3- from the serosal fluid also inhibited the GN effect. In intestinal sac experiments, mucosal GN stimulated luminal secretion of both Cl- and Na+, which was blocked by serosal DNDS. These results suggest that Cl- is taken up at the serosal side by DNDS-sensitive anion exchanger (AE) coupled with Na+-HCO3- cotransporter (NBC) but not by Na+-K+-2Cl- cotransporter 1 (NKCC1), and Cl- is secreted by unknown DPC-sensitive Cl- channel (ClC) at the mucosal side. The transcriptomic analysis combined with qPCR showed low expression of NKCC1 gene and no upregulation of the gene after seawater transfer, while high expression of ClC2 gene and upregulation after seawater transfer. In addition, SO42- transporters (apical Slc26a3/6 and basolateral Slc26a1) are also candidates for transcellular Cl- secretion in exchange of luminal SO42. Na+ secretion could occur through a paracellular route, as Na+-leaky claudin15 was highly expressed and upregulated after seawater transfer. High local Na+ concentration in the lateral interspace produced by Na+/K+-ATPase (NKA) coupled with K+ channels (Kir5.1b) seems to facilitate the paracellular transport. In situ hybridization confirmed the expression of the candidate genes in the epithelial enterocytes. Together with our previous results, we suggest that GN stimulates basolateral NBCela/AE2 and apical ClC2 to increase transcellular Cl- secretion in seawater eel intestine, which differs from the involvement of apical CFTR and basolateral NKCC1 as suggested in mammals and other teleosts.
Collapse
Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
| | - Masaaki Ando
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Marty K S Wong
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan
| | - Takehiro Tsukada
- Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Chiba 274-8510, Japan
| |
Collapse
|
2
|
Takei Y. Evolution of the membrane/particulate guanylyl cyclase: From physicochemical sensors to hormone receptors. Gen Comp Endocrinol 2022; 315:113797. [PMID: 33957096 DOI: 10.1016/j.ygcen.2021.113797] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/19/2021] [Accepted: 04/28/2021] [Indexed: 12/26/2022]
Abstract
Guanylyl cyclase (GC) is an enzyme that produces 3',5'-cyclic guanosine monophosphate (cGMP), one of the two canonical cyclic nucleotides used as a second messenger for intracellular signal transduction. The GCs are classified into two groups, particulate/membrane GCs (pGC) and soluble/cytosolic GCs (sGC). In relation to the endocrine system, pGCs include hormone receptors for natriuretic peptides (GC-A and GC-B) and guanylin peptides (GC-C), while sGC is a receptor for nitric oxide and carbon monoxide. Comparing the functions of pGCs in eukaryotes, it is apparent that pGCs perceive various environmental factors such as light, temperature, and various external chemical signals in addition to endocrine hormones, and transmit the information into the cell using the intracellular signaling cascade initiated by cGMP, e.g., cGMP-dependent protein kinases, cGMP-sensitive cyclic nucleotide-gated ion channels and cGMP-regulated phosphodiesterases. Among vertebrate pGCs, GC-E and GC-F are localized on retinal epithelia and are involved in modifying signal transduction from the photoreceptor, rhodopsin. GC-D and GC-G are localized in olfactory epithelia and serve as sensors at the extracellular domain for external chemical signals such as odorants and pheromones. GC-G also responds to guanylin peptides in the urine, which alters sensitivity to other chemicals. In addition, guanylin peptides that are secreted into the intestinal lumen, a pseudo-external environment, act on the GC-C on the apical membrane for regulation of epithelial transport. In this context, GC-C and GC-G appear to be in transition from exocrine pheromone receptor to endocrine hormone receptor. The pGCs also exist in various deuterostome and protostome invertebrates, and act as receptors for environmental, exocrine and endocrine factors including hormones. Tracing the evolutionary history of pGCs, it appears that pGCs first appeared as a sensor for physicochemical signals in the environment, and then evolved to function as hormone receptors. In this review, the author proposes an evolutionary history of pGCs that highlights the emerging role of the GC/cGMP system for signal transduction in hormone action.
Collapse
Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba 277-8564, Japan.
| |
Collapse
|
3
|
Takei Y. The digestive tract as an essential organ for water acquisition in marine teleosts: lessons from euryhaline eels. ZOOLOGICAL LETTERS 2021; 7:10. [PMID: 34154668 PMCID: PMC8215749 DOI: 10.1186/s40851-021-00175-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 04/16/2021] [Indexed: 05/17/2023]
Abstract
Adaptation to a hypertonic marine environment is one of the major topics in animal physiology research. Marine teleosts lose water osmotically from the gills and compensate for this loss by drinking surrounding seawater and absorbing water from the intestine. This situation is in contrast to that in mammals, which experience a net osmotic loss of water after drinking seawater. Water absorption in fishes is made possible by (1) removal of monovalent ions (desalinization) by the esophagus, (2) removal of divalent ions as carbonate (Mg/CaCO3) precipitates promoted by HCO3- secretion, and (3) facilitation of NaCl and water absorption from diluted seawater by the intestine using a suite of unique transporters. As a result, 70-85% of ingested seawater is absorbed during its passage through the digestive tract. Thus, the digestive tract is an essential organ for marine teleost survival in the hypertonic seawater environment. The eel is a species that has been frequently used for osmoregulation research in laboratories worldwide. The eel possesses many advantages as an experimental animal for osmoregulation studies, one of which is its outstanding euryhalinity, which enables researchers to examine changes in the structure and function of the digestive tract after direct transfer from freshwater to seawater. In recent years, the molecular mechanisms of ion and water transport across epithelial cells (the transcellular route) and through tight junctions (the paracellular route) have been elucidated for the esophagus and intestine. Thanks to the rapid progress in analytical methods for genome databases on teleosts, including the eel, the molecular identities of transporters, channels, pumps and junctional proteins have been clarified at the isoform level. As 10 y have passed since the previous reviews on this subject, it seems relevant and timely to summarize recent progress in research on the molecular mechanisms of water and ion transport in the digestive tract in eels and to compare the mechanisms with those of other teleosts and mammals from comparative and evolutionary viewpoints. We also propose future directions for this research field to achieve integrative understanding of the role of the digestive tract in adaptation to seawater with regard to pathways/mechanisms including the paracellular route, divalent ion absorption, metabolon formation and cellular trafficking of transporters. Notably, some of these have already attracted practical attention in laboratories.
Collapse
Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
| |
Collapse
|
4
|
Ruhr IM, Schauer KL, Takei Y, Grosell M. Renoguanylin stimulates apical CFTR translocation and decreases HCO 3- secretion through PKA activity in the Gulf toadfish ( Opsanus beta). ACTA ACUST UNITED AC 2018; 221:jeb.173948. [PMID: 29361605 DOI: 10.1242/jeb.173948] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/15/2018] [Indexed: 01/07/2023]
Abstract
The guanylin peptides - guanylin, uroguanylin and renoguanylin (RGN) - are endogenously produced hormones in teleost fish enterocytes that are activators of guanylyl cyclase-C (GC-C) and are potent modulators of intestinal physiology, particularly in seawater teleosts. Most notably, they reverse normal net ion-absorbing mechanisms that are vital to water absorption, an important process for seawater teleost survival. The role of guanylin-peptide stimulation of the intestine remains unclear, but it is hypothesized to facilitate the removal of solids from the intestine by providing fluid to enable their removal by peristalsis. The present study used one member of this group of peptides - RGN - to provide evidence for the prominent role that protein kinase A (PKA) plays in mediating the effects of guanylin-peptide stimulation in the posterior intestine of the Gulf toadfish (Opsanus beta). Protein kinase G was found to not mediate the intracellular effects of RGN, despite previous evidence showing that GC-C activation leads to higher cyclic guanosine monophosphate formation. RGN reversed the absorptive short-circuit current and increased conductance in the Gulf toadfish intestine. These effects are correlated to increased trafficking of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel to the apical membrane, which is negated by PKA inhibition. Moreover, RGN decreased HCO3- secretion, likely by limiting apical HCO3-/Cl- exchange (possibly by reducing SLC26a6 activity), a reduction that was enhanced by PKA inhibition. RGN seems to alter PKA activity in the posterior intestine to recruit CFTR to the apical membrane and reduce HCO3- secretion.
Collapse
Affiliation(s)
- Ilan M Ruhr
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, FL 33149, USA
| | - Kevin L Schauer
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, FL 33149, USA
| | - Yoshio Takei
- Department of Marine Bioscience, The Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Martin Grosell
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, FL 33149, USA
| |
Collapse
|
5
|
Hu H, Kortner TM, Gajardo K, Chikwati E, Tinsley J, Krogdahl Å. Intestinal Fluid Permeability in Atlantic Salmon (Salmo salar L.) Is Affected by Dietary Protein Source. PLoS One 2016; 11:e0167515. [PMID: 27907206 PMCID: PMC5132168 DOI: 10.1371/journal.pone.0167515] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 11/15/2016] [Indexed: 12/05/2022] Open
Abstract
In Atlantic salmon (Salmo salar L.), and also in other fish species, certain plant protein ingredients can increase fecal water content creating a diarrhea-like condition which may impair gut function and reduce fish growth. The present study aimed to strengthen understanding of the underlying mechanisms by observing effects of various alternative plant protein sources when replacing fish meal on expression of genes encoding proteins playing key roles in regulation of water transport across the mucosa of the distal intestine (DI). A 48-day feeding trial was conducted with five diets: A reference diet (FM) in which fish meal (72%) was the only protein source; Diet SBMWG with a mix of soybean meal (30%) and wheat gluten (22%); Diet SPCPM with a mix of soy protein concentrate (30%) and poultry meal (6%); Diet GMWG with guar meal (30%) and wheat gluten (14.5%); Diet PM with 58% poultry meal. Compared to fish fed the FM reference diet, fish fed the soybean meal containing diet (SBMWG) showed signs of enteritis in the DI, increased fecal water content of DI chyme and higher plasma osmolality. Altered DI expression of a battery of genes encoding aquaporins, ion transporters, tight junction and adherens junction proteins suggested reduced transcellular transport of water as well as a tightening of the junction barrier in fish fed the SBMWG diet, which may explain the observed higher fecal water content and plasma osmolality. DI structure was not altered for fish fed the other experimental diets but alterations in target gene expression and fecal water content were observed, indicating that alterations in water transport components may take place without clear effects on intestinal structure.
Collapse
Affiliation(s)
- Haibin Hu
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway
- Key Laboratory of Aquaculture Nutrition and Feed (Ministry of Agriculture) & Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, Shandong, P. R. China
| | - Trond M. Kortner
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Karina Gajardo
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway
| | - Elvis Chikwati
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway
| | - John Tinsley
- BioMar Ltd., Grangemouth Docks, Grangemouth, United Kingdom
| | - Åshild Krogdahl
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway
| |
Collapse
|
6
|
Ruhr IM, Takei Y, Grosell M. The role of the rectum in osmoregulation and the potential effect of renoguanylin on SLC26a6 transport activity in the Gulf toadfish (Opsanus beta). Am J Physiol Regul Integr Comp Physiol 2016; 311:R179-91. [PMID: 27030664 DOI: 10.1152/ajpregu.00033.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/28/2016] [Indexed: 01/14/2023]
Abstract
Teleosts living in seawater continually absorb water across the intestine to compensate for branchial water loss to the environment. The present study reveals that the Gulf toadfish (Opsanus beta) rectum plays a comparable role to the posterior intestine in ion and water absorption. However, the posterior intestine appears to rely more on SLC26a6 (a HCO3 (-)/Cl(-) antiporter) and the rectum appears to rely on NKCC2 (SLC12a1) for the purposes of solute-coupled water absorption. The present study also demonstrates that the rectum responds to renoguanylin (RGN), a member of the guanylin family of peptides that alters the normal osmoregulatory processes of the distal intestine, by inhibited water absorption. RGN decreases rectal water absorption more greatly than in the posterior intestine and leads to net Na(+) and Cl(-) secretion, and a reversal of the absorptive short-circuit current (ISC). It is hypothesized that maintaining a larger fluid volume within the distal segments of intestinal tract facilitates the removal of CaCO3 precipitates and other solids from the intestine. Indeed, the expression of the components of the Cl(-)-secretory response, apical CFTR, and basolateral NKCC1 (SLC12a2), are upregulated in the rectum of the Gulf toadfish after 96 h in 60 ppt, an exposure that increases CaCO3 precipitate formation relative to 35 ppt. Moreover, the downstream intracellular effects of RGN appear to directly inhibit ion absorption by NKCC2 and anion exchange by SLC26a6. Overall, the present findings elucidate key electrophysiological differences between the posterior intestine and rectum of Gulf toadfish and the potent regulatory role renoguanylin plays in osmoregulation.
Collapse
Affiliation(s)
- Ilan M Ruhr
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, Florida; and
| | - Yoshio Takei
- Department of Marine Bioscience, The Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Martin Grosell
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, Florida; and
| |
Collapse
|
7
|
Ruhr IM, Mager EM, Takei Y, Grosell M. The differential role of renoguanylin in osmoregulation and apical Cl−/HCO3− exchange activity in the posterior intestine of the Gulf toadfish (Opsanus beta). Am J Physiol Regul Integr Comp Physiol 2015; 309:R399-409. [DOI: 10.1152/ajpregu.00118.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 05/20/2015] [Indexed: 11/22/2022]
Abstract
The guanylin family of peptides are effective regulators of intestinal physiology in marine teleosts. In the distal intestinal segments, they inhibit or reverse fluid absorption by inhibiting the absorptive short-circuit current ( Isc). The present findings demonstrate that mRNA from guanylin and uroguanylin, as well as at least one isoform of the guanylin peptide receptor, apical guanylyl cyclase-C (GC-C), was highly expressed in the intestine and rectum of the Gulf toadfish ( Opsanus beta). In the posterior intestine, GC-C, as well as the cystic fibrosis transmembrane conductance regulator and basolateral Na+/K+/2Cl− cotransporter, which comprise a Cl−-secretory pathway, were transcriptionally upregulated in 60 parts per thousand (ppt). The present study also shows that, in intestinal tissues from Gulf toadfish held in 35 ppt, renoguanylin (RGN) expectedly causes net Cl− secretion, inhibits both the absorptive Isc and fluid absorption, and decreases HCO3− secretion. Likewise, in intestinal tissues from Gulf toadfish acclimated to 60 ppt, RGN also inhibits the absorptive Isc and fluid absorption but to an even greater extent, corresponding with the mRNA expression data. In contrast, RGN does not alter Cl− flux and, instead, elevates HCO3− secretion in the 60-ppt group, suggesting increased apical Cl−/HCO3− exchange activity by SLC26a6. Overall, these findings reinforce the hypotheses that the guanylin peptide system is important for salinity acclimatization and that the secretory response could facilitate the removal of solids, such as CaCO3 precipitates, from the intestine.
Collapse
Affiliation(s)
- Ilan M. Ruhr
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, Florida
| | - Edward M. Mager
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, Florida
| | - Yoshio Takei
- Department of Marine Bioscience, The Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Martin Grosell
- Department of Marine Biology and Ecology, The Rosenstiel School of Marine and Atmospheric Science, The University of Miami, Miami, Florida
| |
Collapse
|
8
|
Takei Y. From Aquatic to Terrestrial Life: Evolution of the Mechanisms for Water Acquisition. Zoolog Sci 2015; 32:1-7. [DOI: 10.2108/zs140142] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
9
|
Ando M, Takei Y. Guanylin activates Cl(-) secretion into the lumen of seawater eel intestine via apical Cl(-) channel under simulated in vivo conditions. Am J Physiol Regul Integr Comp Physiol 2014; 308:R400-10. [PMID: 25540100 DOI: 10.1152/ajpregu.00333.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Guanylin (GN) action on seawater eel intestine was examined under simulated in vivo conditions, where isotonic luminal fluid has low NaCl and high MgSO4 (MgSO4 Ringer). In Ussing chamber, MgSO4 Ringer induced serosa-negative potential difference (PD) even after bumetanide treatment, which is due to the higher paracellular Na(+) permeability over Cl(-), as confirmed by the replacement by MgCl2 (no Cl(-) gradient) or Na2SO4 Ringer (no Na(+) gradient). Luminal GN reversed serosa-negative PD, probably by enhancing Cl(-) secretion into the lumen, as the GN effect was blocked by apical Cl(-) channel blockers [diphenylamine-2-carboxylic acid (DPC), 5-nitro-2-(3-phenylpropylamino) benzoic acid, glibenclamide but not cystic fibrosis transmembrane regulator (CFTR)inh-172] or replacement of luminal fluid by MgCl2 Ringer. The blockers' effect was undetectable when normal Ringer was on both sides. In the sac preparation, NaCl secretion occurred into the lumen (Na(+) > Cl(-)), and GN further enhanced Cl(-) secretion (Cl(-) > Na(+)), resulting in water secretion. These GN effects were also blocked by DPC. Quantitative analyses showed that isotonic NaCl is absorbed when luminal fluid is normal Ringer, but, when luminal fluid is MgSO4 Ringer, hypertonic NaCl, almost equivalent to seawater, is secreted into the lumen after GN. These results indicate that GN stimulates the secretion of hypertonic NaCl into the lumen of seawater eel intestine, like rectal gland of marine elasmobranchs, to get rid of excess NaCl although marine teleost intestine is thought to have only absorptive-type cells with a unique Na-K-Cl cotransport system. The secreted NaCl may activate the cotransport system and further help absorb water in the final segment of seawater eel intestine.
Collapse
Affiliation(s)
- Masaaki Ando
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| |
Collapse
|
10
|
Wong MKS, Ozaki H, Suzuki Y, Iwasaki W, Takei Y. Discovery of osmotic sensitive transcription factors in fish intestine via a transcriptomic approach. BMC Genomics 2014; 15:1134. [PMID: 25520040 PMCID: PMC4377849 DOI: 10.1186/1471-2164-15-1134] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 12/09/2014] [Indexed: 11/10/2022] Open
Abstract
Background Teleost intestine is crucial for seawater acclimation by sensing osmolality of imbibed seawater and regulating drinking and water/ion absorption. Regulatory genes for transforming intestinal function have not been identified. A transcriptomic approach was used to search for such genes in the intestine of euryhaline medaka. Results Quantitative RNA-seq by Illumina Hi-Seq Sequencing method was performed to analyze intestinal gene expression 0 h, 1 h, 3 h, 1 d, and 7 d after seawater transfer. Gene ontology (GO) enrichment results showed that cell adhesion, signal transduction, and protein phosphorylation gene categories were augmented soon after transfer, indicating a rapid reorganization of cellular components and functions. Among >50 transiently up-regulated transcription factors selected via co-expression correlation and GO selection, five transcription factors, including CEBPB and CEBPD, were confirmed by quantitative PCR to be specific to hyperosmotic stress, while others were also up-regulated after freshwater control transfer, including some well-known osmotic-stress transcription factors such as SGK1 and TSC22D3/Ostf1. Protein interaction networks suggest a high degree of overlapping among the signaling of transcription factors that respond to osmotic and general stresses, which sheds light on the interpretation of their roles during hyperosmotic stress and emergency. Conclusions Since cortisol is an important hormone for seawater acclimation as well as for general stress in teleosts, emergency and osmotic challenges could have been evolved in parallel and resulted in the overlapped signaling networks. Our results revealed important interactions among transcription factors and offer a multifactorial perspective of genes involved in seawater acclimation. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1134) contains supplementary material, which is available to authorized users.
Collapse
|
11
|
Ruhr IM, Bodinier C, Mager EM, Esbaugh AJ, Williams C, Takei Y, Grosell M. Guanylin peptides regulate electrolyte and fluid transport in the Gulf toadfish (Opsanus beta) posterior intestine. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1167-79. [DOI: 10.1152/ajpregu.00188.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The physiological effects of guanylin (GN) and uroguanylin (UGN) on fluid and electrolyte transport in the teleost fish intestine have yet to be thoroughly investigated. In the present study, the effects of GN, UGN, and renoguanylin (RGN; a GN and UGN homolog) on short-circuit current ( Isc) and the transport of Cl−, Na+, bicarbonate (HCO3−), and fluid in the Gulf toadfish ( Opsanus beta) intestine were determined using Ussing chambers, pH-stat titration, and intestinal sac experiments. GN, UGN, and RGN reversed the Isc of the posterior intestine (absorptive-to-secretory), but not of the anterior intestine. RGN decreased baseline HCO3− secretion, but increased Cl− and fluid secretion in the posterior intestine. The secretory response of the posterior intestine coincides with the presence of basolateral NKCC1 and apical cystic fibrosis transmembrane conductance regulator (CFTR), the latter of which is lacking in the anterior intestine and is not permeable to HCO3− in the posterior intestine. However, the response to RGN by the posterior intestine is counterintuitive given the known role of the marine teleost intestine as a salt- and water-absorbing organ. These data demonstrate that marine teleosts possess a tissue-specific secretory response, apparently associated with seawater adaptation, the exact role of which remains to be determined.
Collapse
Affiliation(s)
- Ilan M. Ruhr
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida; and
| | - Charlotte Bodinier
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida; and
| | - Edward M. Mager
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida; and
| | - Andrew J. Esbaugh
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida; and
| | - Cameron Williams
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida; and
| | - Yoshio Takei
- Ocean Research Institute, University of Tokyo, Tokyo, Japan
| | - Martin Grosell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida; and
| |
Collapse
|
12
|
Ando M, Wong MKS, Takei Y. Mechanisms of guanylin action on water and ion absorption at different regions of seawater eel intestine. Am J Physiol Regul Integr Comp Physiol 2014; 307:R653-63. [PMID: 24990857 DOI: 10.1152/ajpregu.00543.2013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Guanylin (GN) inhibited water absorption and short-circuit current (Isc) in seawater eel intestine. Similar inhibition was observed after bumetanide, and the effect of bumetanide was abolished by GN or vice versa, suggesting that both act on the same target, Na(+)-K(+)-2Cl(-) cotransporter (NKCC), which is a key player for the Na(+)-K(+)-Cl(-) transport system responsible for water absorption in marine teleost intestine. However, effect of GN was always greater than that of bumetanide: 10% greater in middle intestine (MI) and 40% in posterior intestine (PI) for Isc, and 25% greater in MI and 34% in PI for water absorption. After treatment with GN, Isc decreased to zero, but 20-30% water absorption still remained. The remainder may be due to the Cl(-)/HCO3 (-) exchanger and Na(+)-Cl(-) cotransporter (NCC), since inhibitors for these transporters almost nullified the remaining water absorption. Quantitative PCR analysis revealed the presence of major proteins involved in water absorption; the NKCC2β and AQP1 genes whose expression was markedly upregulated after seawater acclimation. The SLC26A6 (anion exchanger) and NCCβ genes were also expressed in small amounts. Consistent with the inhibitors' effect, expression of NKCC2β was MI > PI, and that of NCCβ was MI << PI. The present study showed that GN not only inhibits the bumetanide-sensitive Na(+)-K(+)-Cl(-) transport system governed by NKCC2β, but also regulates unknown ion transporters different from GN-insensitive SLC26A6 and NCC. A candidate is cystic fibrosis transmembrane conductance regulator Cl(-) channel, as demonstrated in mammals, but its expression is low in eel intestine, and its role may be minor, as indicated by the small effect of its inhibitors.
Collapse
Affiliation(s)
- Masaaki Ando
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | - Marty K S Wong
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| | - Yoshio Takei
- Laboratory of Physiology, Department of Marine Bioscience, Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan
| |
Collapse
|
13
|
|
14
|
The gastrointestinal tract as an endocrine/neuroendocrine/paracrine organ: organization, chemical messengers and physiological targets. FISH PHYSIOLOGY 2010. [DOI: 10.1016/s1546-5098(10)03007-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
15
|
Lessa LMA, Amorim JBO, Fonteles MC, Malnic G. Effect of renoguanylin on hydrogen/bicarbonate ion transport in rat renal tubules. ACTA ACUST UNITED AC 2009; 157:37-43. [PMID: 19540271 DOI: 10.1016/j.regpep.2009.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 03/26/2009] [Accepted: 06/03/2009] [Indexed: 12/28/2022]
Abstract
Renoguanylin (REN) is a recently described member of the guanylin family, which was first isolated from eels and is expressed in intestinal and specially kidney tissues. In the present work we evaluate the effects of REN on the mechanisms of hydrogen transport in rat renal tubules by the stationary microperfusion method. We evaluated the effect of 1 muM and 10 muM of renoguanylin (REN) on the reabsorption of bicarbonate in proximal and distal segments and found that there was a significant reduction in bicarbonate reabsorption. In proximal segments, REN promoted a significant effect at both 1 and 10 muM concentrations. Comparing control and REN concentration of 1 muM, JHCO(3)(-), nmol cm(-2) s(-1)-1,76+/-0,11(control)x1,29+/-0,08(REN 10 muM); P<0.05, was obtained. In distal segments the effect of both concentrations of REN was also effective, being significant e.g. at a concentration of 1 muM (JHCO(3)(-), nmol cm(-2) s(-)1-0.80+/-0.07(control)x0.60+/-0.06(REN 1 muM); P<0.05), although at a lower level than in the proximal tubule. Our results suggest that the action of REN on hydrogen transport involves the inhibition of Na(+)/H(+)exchanger and H(+)-ATPase in the luminal membrane of the perfused tubules by a PKG dependent pathway.
Collapse
Affiliation(s)
- L M A Lessa
- Dept. Physiology and Biophysics, Inst. of Biomedical Sciences, Univ. São Paulo, Av. Prof. Lineu Prestes 1524, 05508-900 São Paulo, Brazil
| | | | | | | |
Collapse
|
16
|
Takei Y. Exploring novel hormones essential for seawater adaptation in teleost fish. Gen Comp Endocrinol 2008; 157:3-13. [PMID: 18452919 DOI: 10.1016/j.ygcen.2008.03.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Revised: 03/11/2008] [Accepted: 03/12/2008] [Indexed: 12/29/2022]
Abstract
Marine fish are dehydrated in hyperosmotic seawater (SW), but maintain water balance by drinking surrounding SW if they are capable of excreting the excess ions, particularly Na(+) and Cl(-), absorbed with water by the intestine. An integrative approach is essential for understanding the mechanisms for SW adaptation, in which hormones play pivotal roles. Comparative genomic analyses have shown that hormones that have Na(+)-extruding and vasodepressor properties are greatly diversified in teleost fish. Physiological studies at molecular to organismal levels have revealed that these diversified hormones are much more potent and efficacious in teleost fish than in mammals and are important for survival in SW and for maintenance of low arterial pressure in a gravity-free aquatic environment. This is typified by the natriuretic peptide (NP) family, which is diversified into seven members (ANP, BNP, VNP and CNP1, 2, 3 and 4) and exerts potent hyponatremic and vasodepressor actions in marine fish. Another example is the guanylin family, which consists of three paralogs (guanylin, uroguanylin and renoguanylin), and stimulates Cl(-) secretion into the intestinal lumen and activates the absorptive-type Na-K-2Cl cotransporter by local luminocrine actions. The most recent addition is the adrenomedullin (AM) family, which has five members (AM1, 2, 3, 4 and 5), with AM2 and AM5 showing the most potent or efficacious vasodepressor and osmoregulatory effects among known hormones in teleost fish. Accumulating evidence strongly indicates that members of these diversified hormone families play essential roles in SW adaptation in teleost fish. In this short review, the author has attempted to propose a novel approach for identification of new hormones that are important for SW adaptation using comparative genomic and functional studies. The author has also suggested potential hormone families that are diversified in teleost fish and appear to be involved in SW adaptation through their ion-extruding actions.
Collapse
Affiliation(s)
- Yoshio Takei
- Laboratory of Physiology, Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano, Tokyo 164-8639, Japan.
| |
Collapse
|