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Con P, Nitzan T, Cnaani A. Corrigendum: Salinity-Dependent Shift in the Localization of Three Peptide Transporters along the Intestine of the Mozambique Tilapia ( Oreochromis mossambicus). Front Physiol 2020; 11:62. [PMID: 32116772 PMCID: PMC7017804 DOI: 10.3389/fphys.2020.00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/21/2020] [Indexed: 11/23/2022] Open
Affiliation(s)
- Pazit Con
- Agricultural Research Organization, Institute of Animal Science, Rishon Letziyon, Israel.,Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tali Nitzan
- Agricultural Research Organization, Institute of Animal Science, Rishon Letziyon, Israel
| | - Avner Cnaani
- Agricultural Research Organization, Institute of Animal Science, Rishon Letziyon, Israel
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Con P, Nitzan T, Slosman T, Harpaz S, Cnaani A. Peptide Transporters in the Primary Gastrointestinal Tract of Pre-Feeding Mozambique Tilapia Larva. Front Physiol 2019; 10:808. [PMID: 31333482 PMCID: PMC6624445 DOI: 10.3389/fphys.2019.00808] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 06/06/2019] [Indexed: 01/19/2023] Open
Abstract
Fish larvae differ greatly from the adult form in their morphology and organ functionality. The functionality of the gastrointestinal tract depends on the expression of various pumps, transporters, and channels responsible for feed digestion and nutrients absorption. During the larval period, the gastrointestinal tract develops from a simple closed tube, into its complex form with differentiated segments, crypts and villi, as found in the adult. In this study, we characterized the expression of three peptide transporters (PepT1a, PepT1b, and PepT2) in the gastrointestinal tract of Mozambique tilapia (Oreochromis mossambicus) larvae along 12 days of development, from pre-hatching to the completion of yolk sac absorption. Gene expression analysis revealed differential and complimentary time-dependent expression of the PepT1 variants and PepT2 along the larval development period. Immunofluorescence analysis showed differential protein localization of the three peptide transporters (PepTs) along the gastrointestinal tract, in a similar pattern to the adult. In addition, PepT1a was localized in mucosal cells in the larvae esophagus, in much higher abundance than in the adults. The results of this study demonstrate specialization of intestinal sections and absorbance potential of the enterocytes prior to the onset of active exogenous feeding, thus pointing to an uncharacterized function and role of the gastrointestinal tract and its transporters during the larval period.
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Affiliation(s)
- Pazit Con
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeZion, Israel.,Department of Animal Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tali Nitzan
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeZion, Israel
| | - Tatiana Slosman
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeZion, Israel
| | - Sheenan Harpaz
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeZion, Israel
| | - Avner Cnaani
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeZion, Israel
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Abstract
The objective of this study was to characterize the expression profile, transport kinetics, and regulation of peptide transporters in bovine mammary epithelial cells (BMECs). Quantitative reverse-transcription real-time PCR, Western blotting, and immunofluorescence staining were used to investigate the expression of peptide transporters in bovine mammary tissues. The effects of time, pH, concentration, and specific inhibitors on β-alanyl-l-lysyl- Nε-7-amino-4-methyl-coumarin-3-acetic acid (β-Ala-Lys-AMCA) uptake in BMECs were also studied. The results showed that the peptide transporters PepT2 and PhT1 are both expressed in bovine mammary glands. The optimal pH for the uptake of β-Ala-Lys-AMCA in BMECs was 6.5. The transport-kinetics study suggested that the uptake of β-Ala-Lys-AMCA in BMECs is saturable over the tested concentration, with a Km value of 82 ± 18 μM and a Vmax of 124 ± 11 pmol/min per milligram of protein. Other dipeptides, including Gly-Sar, Met-Gly, and Met-Met, competitively inhibited β-Ala-Lys-AMCA uptake in BMECs. However, histidine had no effect on β-Ala-Lys-AMCA uptake. Furthermore, knocking down PepT2 could significantly reduce β-Ala-Lys-AMCA uptake, but PhT1 interference had no effect on peptide uptake in BMECs. The inhibition of PI3K and Akt decreased the uptake of β-Ala-Lys-AMCA. The above results revealed functional characteristics of peptide transporters and demonstrated that PepT2 may play a major role in β-Ala-Lys-AMCA uptake in BMECs. Moreover, the PI3K-Akt signaling pathway may regulate the uptake of β-Ala-Lys-AMCA in BMECs.
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Affiliation(s)
- Caihong Wang
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
| | - Yalu Sun
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
| | - Feng-Qi Zhao
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
- Department of Animal and Veterinary Sciences , University of Vermont , Burlington , Vermont 05405 , United States
| | - Jianxin Liu
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
| | - Hongyun Liu
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
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Chourasia TK, D'Cotta H, Baroiller JF, Slosman T, Cnaani A. Effects of the acclimation to high salinity on intestinal ion and peptide transporters in two tilapia species that differ in their salinity tolerance. Comp Biochem Physiol A Mol Integr Physiol 2018; 218:16-23. [PMID: 29366921 DOI: 10.1016/j.cbpa.2018.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/11/2018] [Accepted: 01/11/2018] [Indexed: 02/06/2023]
Abstract
Tilapiine species, widely distributed across habitats with diverse water salinities, are important to aquaculture as well as a laboratory model. The effects of water salinity on two tilapia species, that differ in their salinity tolerance, was evaluated. Oreochromis niloticus reared in brackish-water, showed a significant decrease in growth and feed efficiency, whereas O. mossambicus reared in seawater did not show any significant changes. The expression and activity of Na+/K+-ATPase (NKA), V-type H+-ATPase (VHA) and carbonic anhydrase (CA), as well as expression levels of genes encoding two HCO3- and three peptide transporters (nbc1, slc26a6, slc15a1a, slc15a1b and slc15a2) were measured in three intestinal sections of these two species, grown in freshwater and brackish/sea-water. Overall, the spatial distribution along the intestine of the genes examined in this study was similar between the two species, with the exception of tcaIV. The salinity response, on the other hand, varied greatly between these species. In O. mossambicus, there was a salinity-dependent increased expression of most of the examined genes (except slc26a6 and slc15a2), while in O. niloticus the expression of most genes did not change, or even decreased (tcaIV, nbc1 and slc15a1b). This study highlighted differences in the intestinal response to salinity acclimation between closely- related species that differ in their salinity tolerance. O. mossambicus, which has a high salinity tolerance, showed expression patterns and responses similar to marine species, and differed from the low-salinity-tolerance O. niloticus, which showed a response that differed from the accepted models, that are based on marine and diadromous fishes.
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Con P, Nitzan T, Cnaani A. Salinity-Dependent Shift in the Localization of Three Peptide Transporters along the Intestine of the Mozambique Tilapia ( Oreochromis mossambicus). Front Physiol 2017; 8:8. [PMID: 28167916 PMCID: PMC5253378 DOI: 10.3389/fphys.2017.00008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/05/2017] [Indexed: 12/15/2022] Open
Abstract
The peptide transporter (PepT) systems are well-known for their importance to protein absorption in all vertebrate species. These symporters use H+ gradient at the apical membrane of the intestinal epithelial cells to mediate the absorption of small peptides. In fish, the intestine is a multifunctional organ, involved in osmoregulation, acid-base regulation, and nutrient absorption. Therefore, we expected environmental stimuli to affect peptide absorption. We examined the effect of three environmental factors; salinity, pH and feeding, on the expression, activity and localization of three PepT transporters (PepT1a, PepT1b, PepT2) along the intestine of the Mozambique tilapia (Oreochromis mossambicus). Quantitative real time PCR (qPCR) analysis demonstrated that the two PepT1 variants are typical to the proximal intestinal section while PepT2 is typical to the distal intestinal sections. Immunofluorescence analysis with custom-made antibodies supported the qPCR results, localized both transporters on the apical membrane of enterocytes and provided the first evidence for the participation of PepT2 in nutrient absorption. This first description of segment-specific expression and localization points to a complementary role of the different peptide transporters, corresponding to the changes in nutrient availability along the intestine. Both gene expression and absorption activity assays showed that an increase in water salinity shifted the localization of the PepT genes transcription and activity down along the intestinal tract. Additionally, an unexpected pH effect was found on the absorption of small peptides, with increased activity at higher pH levels. This work emphasizes the relationships between different functions of the fish intestine and how they are affected by environmental conditions.
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Affiliation(s)
- Pazit Con
- Agricultural Research Organization, Institute of Animal ScienceRishon Letziyon, Israel; Department of Animal Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of JerusalemRehovot, Israel
| | - Tali Nitzan
- Agricultural Research Organization, Institute of Animal Science Rishon Letziyon, Israel
| | - Avner Cnaani
- Agricultural Research Organization, Institute of Animal Science Rishon Letziyon, Israel
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Hart HR, Evans AN, Gelsleichter J, Ahearn GA. Molecular identification and functional characteristics of peptide transporters in the bonnethead shark (Sphyrna tiburo). J Comp Physiol B 2016; 186:855-66. [PMID: 27188191 DOI: 10.1007/s00360-016-0999-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 04/18/2016] [Accepted: 05/10/2016] [Indexed: 12/27/2022]
Abstract
Elasmobranchs are considered to be top marine predators, and in general play important roles in the transfer of energy within marine ecosystems. Despite this, little is known regarding the physiological processes of digestion and nutrient absorption in these fishes. One topic that is particularly understudied is the process of nutrient uptake across the elasmobranch gastrointestinal tract. Given their carnivorous diet, the present study sought to expand knowledge on dietary nutrient uptake in elasmobranchs by focusing on the uptake of products of protein digestion. To accomplish this, a full-length cDNA encoding peptide transporter 1 (PepT1), a protein previously identified within the brush border membrane of vertebrates that is responsible for the translocation of peptides released during digestion by luminal and membrane-bound proteases, was isolated from the bonnethead shark (Sphyrna tiburo). A cDNA encoding the related peptide transporter PepT2 was also isolated from S. tiburo using the same methodology. The presence of PepT1 was then localized in multiple components of the bonnethead digestive tract (esophagus, stomach, duodenum, intestine, rectum, and pancreas) using immunohistochemistry. Vesicle studies were used to identify the apparent affinity of PepT1 and to quantify the rate of dipeptide uptake by its H(+)-dependent cotransporter properties. The results of this study provide insight into the properties of peptide uptake within the bonnethead gut, and can facilitate future work on physiological regulation of protein metabolism and absorption including how these processes may vary in elasmobranchs that exhibit different feeding strategies.
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Affiliation(s)
- Hannah R Hart
- Department of Biology, University of North Florida, 1 UNF Dr., Jacksonville, FL, 32224, USA
| | - Andrew N Evans
- Department of Coastal Sciences, Gulf Coast Research Laboratory, University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS, 39564, USA
| | - James Gelsleichter
- Department of Biology, University of North Florida, 1 UNF Dr., Jacksonville, FL, 32224, USA
| | - Gregory A Ahearn
- Department of Biology, University of North Florida, 1 UNF Dr., Jacksonville, FL, 32224, USA.
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Hu Y, Xie Y, Keep RF, Smith DE. Divergent developmental expression and function of the proton-coupled oligopeptide transporters PepT2 and PhT1 in regional brain slices of mouse and rat. J Neurochem 2014; 129:955-65. [PMID: 24548120 DOI: 10.1111/jnc.12687] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/26/2014] [Accepted: 02/13/2014] [Indexed: 01/22/2023]
Abstract
This study evaluated the developmental gene and protein expression of proton-coupled oligopeptide transporters (POTs: peptide transporter, PepT1 and PepT2; peptide-histidine transporter, PhT1 and PhT2) in different regions of rodent brain, and the age-dependent uptake of a POT substrate, glycylsarcosine (GlySar), in brain slices. Slices were obtained from cerebral cortex, cerebellum and hippocampus of wildtype and PepT2 null mice, and from rats at different ages. Gene and protein expression were determined by real-time PCR and immunoblot analyses. Brain slice uptakes of radiolabeled glycylsarcosine were determined in the absence and presence of excess unlabeled glycylsarcosine or l-histidine, the latter being an inhibitor of PhT1/2 but not PepT1/2. As PepT2 and PhT1 transcripts were abundantly expressed in all three regions of mouse brain, little to no expression was observed for PepT1 and PhT2. PhT1 protein was present in brain regions of adult but not neonatal mice and expression levels increased with age in rats. Glycylsarcosine uptake, inhibition and transporter dominance did not show regional brain or species differences. However, there were clear age-related differences in functional activity, with PepT2 dominating in neonatal mice and rats, and PhT1 dominating in adult rodents. These developmental changes may markedly impact the neural activity of both endogenous and exogenous (drug) peptides/mimetics. Developmental gene and protein expression of peptide transporters was evaluated in various regions of rodent brain, along with age-dependent uptake of dipeptide. We found marked changes in protein expression and functional activity of PhT1 and PepT2, the former predominating in adult and the latter in neonate. These developmental changes may markedly impact the neural activity of endogenous and exogenous peptides/mimetics.
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Affiliation(s)
- Yongjun Hu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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