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Fehsenfeld S, Quijada-Rodriguez AR, Zhouyao H, Durant AC, Donini A, Sachs M, Eck P, Weihrauch D. Hiat1 as a new transporter involved in ammonia regulation. Sci Rep 2023; 13:4416. [PMID: 36932112 PMCID: PMC10023664 DOI: 10.1038/s41598-023-31503-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/13/2023] [Indexed: 03/19/2023] Open
Abstract
The orphan transporter hippocampus-abundant transcript 1 (Hiat1) was first identified in the mammalian brain. Its specific substrate specificity, however, has not been investigated to date. Here, we identified and analyzed Hiat1 in a crustacean, the green crab Carcinus maenas. Our phylogenetic analysis showed that Hiat1 protein is conserved at a considerable level between mammals and this invertebrate (ca. 78% identical and conserved amino acids). Functional expression of Carcinus maenas Hiat1 in Xenopus laevis oocytes demonstrated the capability to transport ammonia (likely NH4+) in a sodium-dependent manner. Furthermore, applying quantitative polymerase chain reaction, our results indicated a physiological role for Carcinus maenas Hiat1 in ammonia homeostasis, as mRNA abundance increased in posterior gills in response to elevated circulating hemolymph ammonia upon exposure to high environmental ammonia. Its ubiquitous mRNA expression pattern also suggests an essential role in general cellular detoxification of ammonia. Overall, our results introduce a new ubiquitously expressed ammonia transporter, consequently demanding revision of our understanding of ammonia handling in key model systems from mammalian kidneys to crustacean and fish gills.
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Affiliation(s)
- Sandra Fehsenfeld
- Département de Biologie, Chimie et Géographie, Université du Quebec à Rimouski, 300 Allée des Ursulines, Rimouski, QC, G5L 3A1, Canada.
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada.
| | - Alex R Quijada-Rodriguez
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada
| | - Haonan Zhouyao
- Department of Food and Human Nutritional Sciences, University of Manitoba, 35 Chancellor's Circle, Winnipeg, MB, R3T 2N2, Canada
| | - Andrea C Durant
- Department of Biology, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada
| | - Andrew Donini
- Department of Biology, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - Maria Sachs
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada
| | - Peter Eck
- Department of Food and Human Nutritional Sciences, University of Manitoba, 35 Chancellor's Circle, Winnipeg, MB, R3T 2N2, Canada
| | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, MB, R3T 2N2, Canada
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2
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Huang M, Shang ZH, Wu MX, Zhang LJ, Zhang YL. Regulation of Rhesus glycoprotein-related genes in large-scale loach Paramisgurnus dabryanus during ammonia loading. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 244:114077. [PMID: 36108439 DOI: 10.1016/j.ecoenv.2022.114077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/04/2022] [Accepted: 09/10/2022] [Indexed: 06/15/2023]
Abstract
Waterborne ammonia is one of the crucial issues that limited production and animal health in aquaculture. Ammonia-tolerant varieties are highly desired in intensive fish farming. Screening for the key regulatory genes of ammonia tolerance is essential for variety breeding. According to the previous hypothesis, Rh glycoproteins play an important role in ammonia excretion in teleosts. However, the ammonia defensive mechanisms are not well described at present for large-scale loach (Paramisgurnus dabryanus), a typical air-breathing and commercially important fish in East Asia. Here we show that the transcription of Rh glycoprotein-related genes was significantly affected by ammonia exposure in this species. Probit analysis showed that 96 h-LC50 of NH4Cl at 23 ℃ and pH 7.2 was 92.64 mmol/L. A significant increase of Rhcg expression in gills was observed after 48 h of 60 mmol/L and 36 h of 80 mmol/L NH4Cl exposure, suggesting that Rhcg present on the apical side of the branchial epithelium facilitates NH3 excretion out of gills. A high concentration of acute ammonia exposure induced elevated Rhbg transcript in the gills of large-scale loaches, while a slight change in Rhbg expression was observed in response to lower ammonia, suggesting that transcriptions of Rhbg genes are activated by a considerably high level of ambient ammonia to eliminate excessive endogenous nitrogen. The Rhag mRNA level in gills of large-scale loaches increased markedly with the prolonging of exposure time from 0 to 36 h of ammonia loading, suggesting Rhag localized in gills may be primarily associated with ammonia handling. During 7-21 days of ammonia exposure, the expression of most Rh glycoproteins-related genes in the gills decreased, indicating that the functional role of Rh glycoproteins is not primarily associated with ammonia defense over a long period (more than 7 days). Although a significant transcript of Rhbg was found in the skin of a large-scale loach, the lack of Rhcg and down-regulation of Rhag may indicate that the skin is not an essential location of ammonia excretion, at least when submerged to high levels of ammonia in the environment. In conclusion, Rh glycoproteins localized in gills as ammonia transporters play a momentous role in ammonia detoxification in this species during acute ammonia loading. However, it does not show a positive function during long-term ammonia exposure. Furthermore, the physiological function of Rh glycoproteins localized in the skin is still unclear and deserves further study.
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Affiliation(s)
- Mei Huang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ze-Hao Shang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Meng-Xiao Wu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Lin-Jiang Zhang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Yun-Long Zhang
- College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.
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3
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Chng YR, Ong JLY, Ching B, Chen XL, Hiong KC, Wong WP, Chew SF, Lam SH, Ip YK. Molecular characterization of three Rhesus glycoproteins from the gills of the African lungfish, Protopterus annectens, and effects of aestivation on their mRNA expression levels and protein abundance. PLoS One 2017; 12:e0185814. [PMID: 29073147 PMCID: PMC5657625 DOI: 10.1371/journal.pone.0185814] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 09/20/2017] [Indexed: 11/19/2022] Open
Abstract
African lungfishes are ammonotelic in water. They can aestivate for long periods on land during drought. During aestivation, the gills are covered with dried mucus and ammonia excretion ceases. In fishes, ammonia excretion through the gills involves Rhesus glycoproteins (RhGP/Rhgp). This study aimed to obtain the complete cDNA coding sequences of rhgp from the gills of Protopterus annectens, and to determine their branchial mRNA and protein expression levels during the induction, maintenance and arousal phases of aestivation. Three isoforms of rhgp (rhag, rhbg and rhcg) were obtained in the gills of P. annectens. Their complete cDNA coding sequences ranged between 1311 and 1398 bp, coding for 436 to 465 amino acids with estimated molecular masses between 46.8 and 50.9 kDa. Dendrogramic analyses indicated that Rhag was grouped closer to fishes, while Rhbg and Rhcg were grouped closer to tetrapods. During the induction phase, the protein abundance of Rhag, but not its transcript level, was down-regulated in the gills, suggesting that there could be a decrease in the release of ammonia from the erythrocytes to the plasma. Furthermore, the branchial transcript levels of rhbg and rhcg decreased significantly, in preparation for the subsequent shutdown of gill functions. During the maintenance phase, the branchial expression levels of rhag/Rhag, rhbg/Rhbg and rhcg/Rhcg decreased significantly, indicating that their transcription and translation were down-regulated. This could be part of an overall mechanism to shut down branchial functions and save metabolic energy used for transcription and translation. It could also be regarded as an adaptive response to stop ammonia excretion. During the arousal phase, it is essential for the lungfish to regain the ability to excrete ammonia. Indeed, the protein abundance of Rhag, Rhbg and Rhcg recovered to the corresponding control levels after 1 day or 3 days of recovery from 6 months of aestivation.
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Affiliation(s)
- You R. Chng
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Jasmine L. Y. Ong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Biyun Ching
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Xiu L. Chen
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Kum C. Hiong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Wai P. Wong
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Shit F. Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore
| | - Siew H. Lam
- Department of Biological Sciences, National University of Singapore, Singapore
- NUS Environmental Research Institute, National University of Singapore, Singapore
| | - Yuen K. Ip
- Department of Biological Sciences, National University of Singapore, Singapore
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4
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Chen XL, Zhang B, Chng YR, Ong JLY, Chew SF, Wong WP, Lam SH, Nakada T, Ip YK. Ammonia exposure affects the mRNA and protein expression levels of certain Rhesus glycoproteins in the gills of climbing perch. ACTA ACUST UNITED AC 2017; 220:2916-2931. [PMID: 28576822 DOI: 10.1242/jeb.157123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 05/30/2017] [Indexed: 01/08/2023]
Abstract
The freshwater climbing perch, Anabas testudineus, is an obligate air-breathing and euryhaline teleost capable of active ammonia excretion and tolerant of high concentrations of environmental ammonia. As Rhesus glycoproteins (RhGP/Rhgp) are known to transport ammonia, this study aimed to obtain the complete cDNA coding sequences of various rhgp isoforms from the gills of A. testudineus, and to determine their mRNA and protein expression levels during 6 days of exposure to 100 mmol l-1 NH4Cl. The subcellular localization of Rhgp isoforms in the branchial epithelium was also examined in order to elucidate the type of ionocyte involved in active ammonia excretion. Four rhgp (rhag, rhbg, rhcg1 and rhcg2) had been identified from the gills of A. testudineus They had conserved amino acid residues for NH4+ binding, NH4+ deprotonation, channel gating and lining of the vestibules. Despite inwardly directed NH3 and NH4+ gradients, there were significant increases in the mRNA expression levels of the four branchial rhgp in A. testudineus at certain time points during 6 days of ammonia exposure, with significant increases in the protein abundances of Rhag and Rhcg2 on day 6. Immunofluorescence microscopy revealed a type of ammonia-inducible Na+/K+-ATPase α1c-immunoreactive ionocyte with apical Rhag and basolateral Rhcg2 in the gills of fish exposed to ammonia for 6 days. Hence, active ammonia excretion may involve NH4+ entering the ionocyte through the basolateral Rhcg2 and being excreted through the apical Rhag, driven by a transapical membrane electrical potential generated by the apical cystic fibrosis transmembrane conductance regulator Cl- channel, as suggested previously.
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Affiliation(s)
- Xiu L Chen
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Biyan Zhang
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - You R Chng
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Jasmine L Y Ong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616, Republic of Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
| | - Siew H Lam
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore.,NUS Environmental Research Institute, National University of Singapore, Kent Ridge, Singapore 117411, Republic of Singapore
| | - Tsutomu Nakada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore 117543, Republic of Singapore
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5
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Yeam CT, Chng YR, Ong JLY, Wong WP, Chew SF, Ip YK. Molecular characterization of two Rhesus glycoproteins from the euryhaline freshwater white-rimmed stingray, Himantura signifer, and changes in their transcript levels and protein abundance in the gills, kidney, and liver during brackish water acclimation. J Comp Physiol B 2017; 187:911-929. [PMID: 28324156 DOI: 10.1007/s00360-017-1067-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 02/05/2017] [Accepted: 02/21/2017] [Indexed: 11/29/2022]
Abstract
Himantura signifer is a freshwater stingray which inhabits rivers in Southeast Asia. It is ammonotelic in fresh water, but retains the capacities of urea synthesis and ureosmotic osmoregulation to survive in brackish water. This study aimed to elucidate the roles of Rhesus glycoproteins (Rhgp), which are known to transport ammonia, in conserving nitrogen (N) in H. signifer during brackish water acclimation when N became limited resulting from increased hepatic urea synthesis. The complete coding sequence of rhbg from H. signifer consisted of 1383 bp, encoding 460 amino acids with an estimated molecular mass of 50.5 kDa, while that of rhcg comprised 1395 bp, encoding for 464 amino acids with an estimated molecular mass of 50.8 kDa. The deduced amino sequences of Rhbg and Rhcg contained ammonia binding sites, which could recruit NH4+ to be deprotonated, and a hydrophobic pore with two histidine residues, which could mediate the transport of NH3. Our results indicated for the first time that brackish water acclimation resulted in significant decreases in the expression levels of rhbg/Rhbg and rhcg/Rhcg in the gills of H. signifer, which offered a mechanistic explanation of brackish water-related decreased ammonia excretion reported elsewhere. Furthermore, rhbg/Rhbg expression levels increased significantly in the liver of H. signifer during brackish water acclimation, indicating that the ammonia produced by extra-hepatic tissues and released into the blood could be channeled into the liver for increased urea synthesis. Overall, these results lend support to the proposition that H. signifer becomes N-limited upon utilizing urea as an osmolyte in brackish water.
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Affiliation(s)
- Cheng T Yeam
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - You R Chng
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - Jasmine L Y Ong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - Wai P Wong
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore
| | - Shit F Chew
- Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore, 637616, Singapore
| | - Yuen K Ip
- Department of Biological Sciences, National University of Singapore, Kent Ridge, Singapore, 117543, Singapore. .,The Tropical Marine Science Institute, National University of Singapore, Kent Ridge, Singapore, 119227, Singapore.
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6
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Chasiotis H, Ionescu A, Misyura L, Bui P, Fazio K, Wang J, Patrick M, Weihrauch D, Donini A. An animal homolog of plant Mep/Amt transporters promotes ammonia excretion by the anal papillae of the disease vector mosquito Aedes aegypti. ACTA ACUST UNITED AC 2016; 219:1346-55. [PMID: 26944496 DOI: 10.1242/jeb.134494] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/22/2016] [Indexed: 12/16/2022]
Abstract
The transcripts of three putative ammonia (NH3/NH4 (+)) transporters, Rhesus-like glycoproteins AeRh50-1, AeRh50-2 and Amt/Mep-like AeAmt1 were detected in the anal papillae of larval Aedes aegypti Quantitative PCR studies revealed 12-fold higher transcript levels of AeAmt1 in anal papillae relative to AeRh50-1, and levels of AeRh50-2 were even lower. Immunoblotting revealed AeAmt1 in anal papillae as a pre-protein with putative monomeric and trimeric forms. AeAmt1 was immunolocalized to the basal side of the anal papillae epithelium where it co-localized with Na(+)/K(+)-ATPase. Ammonium concentration gradients were measured adjacent to anal papillae using the scanning ion-selective electrode technique (SIET) and used to calculate ammonia efflux by the anal papillae. dsRNA-mediated reductions in AeAmt1 decreased ammonia efflux at larval anal papillae and significantly increased ammonia levels in hemolymph, indicating a principal role for AeAmt1 in ammonia excretion. Pharmacological characterization of ammonia transport mechanisms in the anal papillae suggests that, in addition to AeAmt1, the ionomotive pumps V-type H(+)-ATPase and Na(+)/K(+)-ATPase as well as NHE3 are involved in ammonia excretion at the anal papillae.
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Affiliation(s)
- Helen Chasiotis
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Adrian Ionescu
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Lidiya Misyura
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Phuong Bui
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
| | - Kimberly Fazio
- Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Jason Wang
- Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Marjorie Patrick
- Department of Biology, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Dirk Weihrauch
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba, Canada R3T 2N2
| | - Andrew Donini
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3
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