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Chu F, Wan H, Xiao W, Dong H, Lü M. Ca 2+-Permeable Channels/Ca 2+ Signaling in the Regulation of Ileal Na +/Gln Co-Transport in Mice. Front Pharmacol 2022; 13:816133. [PMID: 35281933 PMCID: PMC8905502 DOI: 10.3389/fphar.2022.816133] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/13/2022] [Indexed: 11/13/2022] Open
Abstract
Oral glutamine (Gln) has been widely used in gastrointestinal (GI) clinical practice, but it is unclear if Ca2+ regulates intestinal Gln transport, although both of them are essential nutrients for mammals. Chambers were used to determine Gln (25 mM)-induced Isc through Na+/Gln co-transporters in the small intestine in the absence or the presence of selective activators or blockers of ion channels and transporters. Luminal but not serosal application of Gln induced marked intestinal Isc, especially in the distal ileum. Lowering luminal Na+ almost abolished the Gln-induced ileal Isc, in which the calcium-sensitive receptor (CaSR) activation were not involved. Ca2+ removal from both luminal and serosal sides of the ileum significantly reduced Gln- Isc. Blocking either luminal Ca2+ entry via the voltage-gated calcium channels (VGCC) or endoplasmic reticulum (ER) release via inositol 1,4,5-triphosphate receptor (IP3R) and ryanodine receptor (RyR) attenuated the Gln-induced ileal Isc, Likewise, blocking serosal Ca2+ entry via the store-operated Ca2+ entry (SOCE), TRPV1/2 channels, and Na+/Ca2+ exchangers (NCX) attenuated the Gln-induced ileal Isc. In contrast, activating TRPV1/2 channels enhanced the Gln-induced ileal Isc. We concluded that Ca2+ signaling is critical for intestinal Gln transport, and multiple plasma membrane Ca2+-permeable channels and transporters play roles in this process. The Ca2+ regulation of ileal Na+/Gln transport expands our understanding of intestinal nutrient uptake and may be significant in GI health and disease.
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Affiliation(s)
- Fenglan Chu
- Department of Gastroenterology, Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Weidong Xiao
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Muhan Lü
- Department of Gastroenterology, Affiliated Hospital of Southwest Medical University, Luzhou, China
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Wang S, Bai M, Xu K, Shao Y, Yang Z, Xiong X, Huang R, Li Y, Liu H. Effects of Coated Cysteamine on Oxidative Stress and Inflammation in Weaned Pigs. Animals (Basel) 2021; 11:ani11082217. [PMID: 34438677 PMCID: PMC8388385 DOI: 10.3390/ani11082217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/15/2021] [Accepted: 07/23/2021] [Indexed: 01/11/2023] Open
Abstract
This study aimed to explore the effects of dietary coated cysteamine on oxidative stress and inflammation in diquat-induced weaning pigs. Twenty-four pigs were randomly assigned to three dietary groups with eight replicates: the control (fed base diet), diquat (fed base diet), and coated cysteamine + diquat groups (fed 80 mg/kg cysteamine). The experiment was conducted for 21 d, and consisted of a pre-starter period (14 d) and a starter period (7 d). Coated cysteamine treatment significantly increased (p < 0.05) the final weight and average daily gain (ADG) in pigs. The contents of alkaline phosphatase (ALP), immunoglobulin G (IgG), serine (Ser), and isoleucine (Ile) were elevated (p < 0.05) while the contents of albumin (ALB) and aspartic acid (Asp) were reduced (p < 0.05) in the serum after coated cysteamine supplementation. Coated cysteamine supplementation resulted in greater (p < 0.05) serum superoxide dismutase (SOD) activity, the expression of interleukin-10 (IL-10) mRNA in the colon, and the CuSOD mRNA expression in the jejunum (p < 0.05) and colon (p = 0.073). Coated cysteamine supplementation showed an increasing trend in villus height (p = 0.060), villus height/crypt depth (V/C) (p = 0.056), the expression levels of zonula occludens-1 (ZO-1) mRNA (p = 0.061), and Occludin mRNA (p = 0.074) in the jejunum. In summary, dietary supplementation with coated cysteamine improves the intestinal barrier function of the jejunum by increasing the immunoglobulin content and the relative expression of intestinal immune factor mRNA in pigs while alleviating oxidative stress and inflammatory reactions caused by diquat.
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Affiliation(s)
- Shanshan Wang
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China
| | - Miaomiao Bai
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
| | - Kang Xu
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
| | - Yirui Shao
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
| | - Zhe Yang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China;
| | - Xia Xiong
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
| | - Ruilin Huang
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
| | - Yao Li
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin 150030, China
- Correspondence: (Y.L.); (H.L.)
| | - Hongnan Liu
- Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central, Ministry of Agriculture, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (S.W.); (M.B.); (K.X.); (Y.S.); (X.X.); (R.H.)
- Correspondence: (Y.L.); (H.L.)
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Petro-Sakuma C, Celino-Brady FT, Breves JP, Seale AP. Growth hormone regulates intestinal gene expression of nutrient transporters in tilapia (Oreochromis mossambicus). Gen Comp Endocrinol 2020; 292:113464. [PMID: 32171745 PMCID: PMC7253219 DOI: 10.1016/j.ygcen.2020.113464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 02/07/2023]
Abstract
Among the various ways that growth hormone (GH) underlies the growth physiology of teleost fishes, GH stimulates transport pathways that facilitate the absorption of nutrients across intestinal epithelia. The current study investigated the effects of GH on the gene expression of nutrient transporters in an omnivorous teleost, the Mozambique tilapia (Oreochromis mossambicus). We employed pituitary gland removal (hypophysectomy) and hormone replacement to assess whether GH directs the gene expression of the GH receptor (ghr2), the peptide transporters, pept1a, pept1b and pept2, the amino acid transporter, slc7a9, the Na+/glucose cotransporter, sglt1, the glucose transporter, glut2, and the myo-inositol transporter, smit2, in anterior, middle, and posterior intestine. ghr2 was predominantly expressed in posterior intestine, while pept1a, pept1b, slc7a9, sglt1, glut2, and smit2 exhibited the highest mRNA levels in anterior and/or middle intestine. While hypophysectomized tilapia exhibited diminished expression of ghr2, pept1a, pept1b, slc7a9, and glut2 compared with intact and sham-operated controls, only ghr2, pept1a, pept1b and glut2 levels were restored by GH replacement. Our findings indicate that GH supports growth, at least in part, by stimulating the gene expression of its cognate receptor and key nutrient transporters in the intestine.
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Affiliation(s)
- Cody Petro-Sakuma
- Department of Human Nutrition, Food, and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Fritzie T Celino-Brady
- Department of Human Nutrition, Food, and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA
| | - Jason P Breves
- Department of Biology, Skidmore College, 815 N. Broadway, Saratoga Springs, NY 12866, USA
| | - Andre P Seale
- Department of Human Nutrition, Food, and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, HI 96822, USA; Hawai'i Institute of Marine Biology, University of Hawai'i, Kāne'ohe, HI 96744, USA.
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Abstract
The small intestine mediates the absorption of amino acids after ingestion of protein and sustains the supply of amino acids to all tissues. The small intestine is an important contributor to plasma amino acid homeostasis, while amino acid transport in the large intestine is more relevant for bacterial metabolites and fluid secretion. A number of rare inherited disorders have contributed to the identification of amino acid transporters in epithelial cells of the small intestine, in particular cystinuria, lysinuric protein intolerance, Hartnup disorder, iminoglycinuria, and dicarboxylic aminoaciduria. These are most readily detected by analysis of urine amino acids, but typically also affect intestinal transport. The genes underlying these disorders have all been identified. The remaining transporters were identified through molecular cloning techniques to the extent that a comprehensive portrait of functional cooperation among transporters of intestinal epithelial cells is now available for both the basolateral and apical membranes. Mouse models of most intestinal transporters illustrate their contribution to amino acid homeostasis and systemic physiology. Intestinal amino acid transport activities can vary between species, but these can now be explained as differences of amino acid transporter distribution along the intestine. © 2019 American Physiological Society. Compr Physiol 9:343-373, 2019.
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Affiliation(s)
- Stefan Bröer
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Stephen J Fairweather
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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Zhou P, Luo Y, Zhang L, Li J, Zhang B, Xing S, Zhu Y, Gao F, Zhou G. Effects of cysteamine supplementation on the intestinal expression of amino acid and peptide transporters and intestinal health in finishing pigs. Anim Sci J 2016; 88:314-321. [PMID: 27245869 DOI: 10.1111/asj.12626] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/18/2016] [Accepted: 02/10/2016] [Indexed: 11/30/2022]
Abstract
This study aimed to evaluate the effects of cysteamine supplementation on the expression of jejunal amino acid and peptide transporters and intestinal health in finishing pigs. Sixty barrows were allocated into two experimental diets consisting of a basal control diet supplemented with 0 or 142 mg/kg cysteamine. After 41 days, 10 pigs per treatment were slaughtered. The results showed that cysteamine supplementation increased the apparent digestibility of crude protein (CP) (P < 0.05) and the trypsin activity in jejunal digesta (P < 0.01). Cysteamine supplementation also increased the messenger RNA abundance of SLC7A7, SLC7A9 and SLC15A1, occludin, claudin-1 and zonula occludens protein-1 (P < 0.001) in the jejunum mucosa. Increased glutathione content (P < 0.01) and glutathione peroxidase activity (P < 0.05) and decreased malondialdehyde content (P < 0.01) were observed in pigs receiving cysteamine. Additionally, cysteamine supplementation increased the concentrations of secretory immunoglobulin A (IgA) (P < 0.05), IgM (P < 0.001) and IgG (P < 0.001) in the jejunal mucosa. It is concluded that cysteamine supplementation could influence protein digestion and absorption via increasing trypsin activity, enhancing the digestibility of CP, and promoting the expression of jejunal amino acid and peptide transporters. Moreover, cysteamine improved intestinal integrity, antioxidant capacity and immune function in the jejunum, which were beneficial for intestinal health.
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Affiliation(s)
- Ping Zhou
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Yiqiu Luo
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Lin Zhang
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Jiaolong Li
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Bolin Zhang
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Shen Xing
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Yuping Zhu
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Feng Gao
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
| | - Guanghong Zhou
- College of Animal Science and Technology, Key Laboratory of Animal Origin Food Production and Safety Guarantee of Jiangsu Province, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Nanjing Agricultural University, Nanjing, China
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Zhou J, Fan S, Cao Y, Zhu M, Han Y, Cao X, Li Y. Tumor necrosis factor-α suppresses the protein fractional synthesis rate of the small intestine stimulated by glutamine in rats. Exp Ther Med 2014; 9:547-552. [PMID: 25574232 PMCID: PMC4280961 DOI: 10.3892/etm.2014.2129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 10/21/2014] [Indexed: 12/21/2022] Open
Abstract
The objective of this study was to examine whether and how TNF-α affects glutamine-enhanced protein synthesis and the expression of the amino acid transporter ASCT2 in the small intestine at the mRNA and protein levels. A total of 30 male Sprague-Dawley rats were randomly assigned into three groups, namely the total parenteral nutrition (TPN; control), glutamine-treated (Gln), and glutamine- and tumor necrosis factor-α (TNF-α)-treated (TNF-α) groups. At 30 min prior to examination, all rats were mainlined with [L-15N]leucine. The concentration of TNF-α in plasma and of glutamine in plasma and the small intestine was measured. The fractional synthesis rate (FSR) of protein and the mRNA and protein expression levels of ASCT2 in the small intestine were assessed. The level of TNF-α was highest in the TNF-α group and the glutamine concentration was elevated to a greater extent in the TNF-α group than in the other two groups. However, the FSR of protein in the small intestine was significantly higher in the Gln group compared with that in the TNF-α group. The mRNA and protein expression levels of ASCT2 in the experimental groups were significantly higher that those in the control group, but did not differ significantly between the Gln and TNF-α groups. These results indicate that TNF-α may attenuate glutamine-stimulated protein synthesis in the small intestine in the early stage of sepsis in rats. The mechanism may be that TNF-α inhibits the function of the glutamine transporter in the uptake the glutamine into target cells for protein synthesis. This inhibition may occur at or following protein translation.
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Affiliation(s)
- Jihong Zhou
- Department of Burns and Plastic Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Shengxian Fan
- Department of General Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Yacheng Cao
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210002, P.R. China
| | - Mingfang Zhu
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210002, P.R. China
| | - Yong Han
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210002, P.R. China
| | - Xueying Cao
- Department of Burns and Plastic Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Yousheng Li
- Department of General Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
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Abstract
PURPOSE OF REVIEW We consider recent advances in epithelial amino acid transport physiology and our understanding of the functioning of amino acid transporters as sensors, as well as carriers, of tissue nutrient supplies. RECENT FINDINGS Gut hormones (e.g. leptin) may regulate intestinal amino acid transporter activity by a variety of mechanisms, although the overall functional significance of such regulation is not yet fully understood. Important functional interactions between amino acid transporters and nutrient-signalling pathways which regulate metabolism [e.g. the mammalian target of rapamycin (mTOR)C1 pathway which promotes cell growth] have been revealed in recent studies. Amino acid transporters on endosomal (e.g. lysosomal) membranes may be of unexpected significance as intracellular nutrient sensors. It is also now evident that certain amino acid transporters may have dual receptor-transporter functions and act as 'transceptors' to sense amino acid availability upstream of signal pathways. SUMMARY Increased knowledge on the timescale of the amino acid sensor-signal-effector process(es) should help in the optimization of protein-feeding regimes to gain maximum anabolic effect. New opportunities for nutritional therapy include targeting of amino acid transceptors to promote protein-anabolic signals and mechanisms up-regulating amino acid transporter expression to improve absorptive capacity for nutrients.
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Affiliation(s)
- Nadège Poncet
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, UK
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Glutamine, arginine, and leucine signaling in the intestine. Amino Acids 2009; 37:111-22. [PMID: 19130170 DOI: 10.1007/s00726-008-0225-4] [Citation(s) in RCA: 231] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 12/09/2008] [Indexed: 12/14/2022]
Abstract
Glutamine and leucine are abundant constituents of plant and animal proteins, whereas the content of arginine in foods and physiological fluids varies greatly. Besides their role in protein synthesis, these three amino acids individually activate signaling pathway to promote protein synthesis and possibly inhibit autophagy-mediated protein degradation in intestinal epithelial cells. In addition, glutamine and arginine stimulate the mitogen-activated protein kinase and mammalian target of rapamycin (mTOR)/p70 (s6) kinase pathways, respectively, to enhance mucosal cell migration and restitution. Moreover, through the nitric oxide-dependent cGMP signaling cascade, arginine regulates multiple physiological events in the intestine that are beneficial for cell homeostasis and survival. Available evidence from both in vitro and in vivo animal studies shows that glutamine and arginine promote cell proliferation and exert differential cytoprotective effects in response to nutrient deprivation, oxidative injury, stress, and immunological challenge. Additionally, when nitric oxide is available, leucine increases the migration of intestinal cells. Therefore, through cellular signaling mechanisms, arginine, glutamine, and leucine play crucial roles in intestinal growth, integrity, and function.
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Avissar NE, Sax HC, Toia L. In human entrocytes, GLN transport and ASCT2 surface expression induced by short-term EGF are MAPK, PI3K, and Rho-dependent. Dig Dis Sci 2008; 53:2113-25. [PMID: 18157695 DOI: 10.1007/s10620-007-0120-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 11/05/2007] [Indexed: 01/11/2023]
Abstract
Glutamine, a key nutrient for the enterocyte, is transported among other proteins by ASCT2. Epidermal growth factor (EGF) augments intestinal adaptation. We hypothesized that short-term treatment of human enterocytes with EGF enhances glutamine transport by increasing membranal ASCT2. To elucidate EGF-induced mechanisms, monolayers of C2(BBe)1 w/wo siRho transfection were treated w/wo EGF and w/wo tyrphostin AG1478 (AG1478), wortmanin, or PD98059. Total and system-specific (3)H-glutamine transports were determined w/wo 5 mmol/l amino acid inhibitors. Total and membranal ASCT2 proteins were measured by Westerns. EGF doubled glutamine transport by increasing B(0)/ASCT2 and B(0,+) activities. Despite the doubling of membranal ASCT2 protein with EGF treatment, total ASCT2 did not change. The increases in B(0)/ASCT2 activity and ASCT2 protein were eliminated by AG1478, PD98059, wortmanin, and siRho, while transport by B(0,+) was inhibited only by PD98059 and siRho. Thus, differential pathways are involved in EGF-induced increase in B(0)/ASCT2 glutamine transport and membranal ASCT2 compared to those involved in B(0,+) activity.
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Affiliation(s)
- Nelly E Avissar
- Department of Surgery, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA.
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10
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Bröer S. Amino acid transport across mammalian intestinal and renal epithelia. Physiol Rev 2008; 88:249-86. [PMID: 18195088 DOI: 10.1152/physrev.00018.2006] [Citation(s) in RCA: 614] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The transport of amino acids in kidney and intestine is critical for the supply of amino acids to all tissues and the homeostasis of plasma amino acid levels. This is illustrated by a number of inherited disorders affecting amino acid transport in epithelial cells, such as cystinuria, lysinuric protein intolerance, Hartnup disorder, iminoglycinuria, dicarboxylic aminoaciduria, and some other less well-described disturbances of amino acid transport. The identification of most epithelial amino acid transporters over the past 15 years allows the definition of these disorders at the molecular level and provides a clear picture of the functional cooperation between transporters in the apical and basolateral membranes of mammalian epithelial cells. Transport of amino acids across the apical membrane not only makes use of sodium-dependent symporters, but also uses the proton-motive force and the gradient of other amino acids to efficiently absorb amino acids from the lumen. In the basolateral membrane, antiporters cooperate with facilitators to release amino acids without depleting cells of valuable nutrients. With very few exceptions, individual amino acids are transported by more than one transporter, providing backup capacity for absorption in the case of mutational inactivation of a transport system.
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Affiliation(s)
- Stefan Bröer
- School of Biochemistry and Molecular Biology, Australian National University, Canberra, Australian Capital Territory, Australia.
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11
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Na+-dependent neutral amino acid transporter ASCT2 is downregulated in seriously traumatized human intestinal epithelial cells. J Pediatr Gastroenterol Nutr 2008; 46:71-9. [PMID: 18162837 DOI: 10.1097/01.mpg.0000304457.22670.6f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Serious trauma to the body often is associated with changes in protein metabolism in multiple organs and tissues. Clinically, the catabolic response results in a generalized negative nitrogen balance. Nutrition support has been an important component of the care of seriously traumatized patients. However, during states of severe trauma, enterocyte transport function remains unclear. This study aims to quantitate the Na+-dependent neutral amino acid transport and expression of its transporter in traumatically injured Caco-2 cell lines. MATERIALS AND METHODS Transport and transporter of Na+-dependent neutral amino acid in Caco-2 cell lines were characterized. Then the cell lines were cultured under hypoxic, nutrient-deprived, and ischemic conditions for 1, 2, 4, and 6 hours. After severe trauma was performed, we investigated the transport of Na+-dependent neutral amino acids and the expression of transporter protein and mRNA in apical membrane vesicles. RESULTS Among the neutral amino acid transporters, only ASCT2 mRNA was amplified successfully. Under nutrient-deprived and ischemic conditions, transport of L-alanine and L-glutamine decreased significantly compared with control (P < 0.01), whereas hypoxia had no significant effect. The changes were associated with a decrease in maximum transport velocity without an influence on transport affinity. Expression of relative transporter proteins and mRNA decreased significantly compared with control (P < 0.01). CONCLUSIONS Na+-dependent neutral amino acid transport and its key transporter are differently regulated during state of traumatic injury. It may be of use to provide some strategies targeting the special nutrient requirements and transport capabilities of seriously traumatized patients.
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Huang Q, Li N, Zhu W, Li Q, Li J. Glutamine transporter ASCT2 was down-regulated in ischemic injured human intestinal epithelial cells and reversed by epidermal growth factor. JPEN J Parenter Enteral Nutr 2007; 31:86-93. [PMID: 17308248 DOI: 10.1177/014860710703100286] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Clinically, nutrition support has been an important component of the care of the hypoperfusion traumatized patient who is unable to accept complete volitional nutrition. However, enterocyte transport function during states of intestinal hypoperfusion remains unclear. Glutamine is essential for the viability and growth of intestine epithelial cells, and the Na(+)-dependent neutral amino acid transporter ASCT2 is thought to mainly mediate glutamine transport. This study aims to quantify the change of glutamine transporter ASCT2 expression in ischemic injured Caco-2 cell lines and the regulatory action of epidermal growth factor (EGF) on glutamine transport and its transporter. METHODS Cells were cultured under ischemic conditions for 2 hours. After ischemia was performed, Caco-2 cells were incubated with or without EGF (100 microg/mL) for 0-8 hours. Then we studied the cell membrane l-glutamine transport, the expression of ASCT2 protein, and mRNA. RESULTS After ischemia was performed, Caco-2 cell membrane glutamine transport decreased significantly (p < .01), and the expression of ASCT2 proteins decreased significantly compared with control (p < .01). Under ischemic conditions, expression of ASCT2 mRNA was down-regulated by a real-time polymerase chain reaction (PCR) method. After EGF incubation for 1-2 hours, the proteins and mRNA of ASCT2 were reversed to normal levels (p > .05). CONCLUSIONS In ischemic injured Caco-2 cells, ASCT2 protein expression and mRNA transcription were involved in the down-regulation of Na(+)-dependent glutamine transport. The decrease of glutamine transport and its transporter under ischemic conditions could be reversed by EGF action. These findings may help in the choice of the nutrition support manner and clinical therapy of ischemia-damaged intestinal epithelial cells.
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Affiliation(s)
- Qian Huang
- Research Institute of General Surgery, Jinling Hospital, Nanjing, China
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Casirola DM, Ferraris RP. alpha-Glucosidase inhibitors prevent diet-induced increases in intestinal sugar transport in diabetic mice. Metabolism 2006; 55:832-41. [PMID: 16713445 DOI: 10.1016/j.metabol.2006.02.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 02/01/2006] [Indexed: 10/24/2022]
Abstract
The recommended diet for diabetes mellitus is rich in complex carbohydrates. We have previously shown that high carbohydrate levels in the intestinal lumen induce adaptive increases in sugar absorption which in turn exacerbate postprandial hyperglycemia in diabetic mice. alpha-Glucosidase inhibitors (AGIs) hinder digestion of complex carbohydrates and therefore alleviate postprandial glycemic excursions. In this study, we tested the hypothesis that AGIs prevent the carbohydrate-induced upregulation of intestinal glucose and fructose transport in diabetes. Streptozotocin-diabetic mice were fed the following isocaloric diets: high carbohydrate (H), H plus acarbose (HA), H plus deoxy-nojirimycin (HD), and low carbohydrate (L), then nutrient uptakes were determined after 2 and 4 weeks. Body weight, intestinal weight, and length were independent of diet. Fasting and postprandial blood glucose levels were lower in HA and HD than in H mice. Uptakes of D-glucose and D-fructose were 2 to 3 times greater in H than in L mice, but HA and HM diets gradually reduced D-glucose uptakes to rates similar to L mice. Only HA diets reduced D-fructose uptake. Intestinal proline, aspartate, and glutamine uptakes were each greater in L than in H, HA, and HD mice. alpha-Glucosidase inhibitors did not alter intestinal permeability and amino acid transport rates. alpha-Glucosidase inhibitor-inhibitable increases in total intestinal absorptive capacity for sugars were due to carbohydrate-induced increases in V(max) of glucose transport. Clearly, one potential mechanism by which AGIs blunt postprandial glycemic excursions and lower fasting blood glucose concentrations in individuals consuming carbohydrate-containing diets is by preventing carbohydrate-induced increases in intestinal sugar transport.
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Affiliation(s)
- Donatella M Casirola
- Department of Pharmacology and Physiology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07101-1709, USA
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Sukhotnik I, Coran AG, Kramer A, Shiloni E, Mogilner JG. Advances in short bowel syndrome: an updated review. Pediatr Surg Int 2005; 21:947-53. [PMID: 16267678 DOI: 10.1007/s00383-005-1500-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/07/2005] [Indexed: 01/01/2023]
Abstract
Short bowel syndrome (SBS) continues to be an important clinical problem due to its high mortality and morbidity as well as its devastating socioeconomic effects. The past 3 years have witnessed many advances in the investigation of this condition, with the aim of elucidating the cellular and molecular mechanisms of intestinal adaptation. Such information may provide opportunities to exploit various factors that act as growth agents for the remaining bowel mucosa and may suggest new therapeutic strategies to maintain gut integrity, eliminate dependence on total parenteral nutrition, and avoid the need for intestinal transplantation. This review summarizes current research on SBS over the last few years.
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Affiliation(s)
- Igor Sukhotnik
- Department of Pediatric Surgery B, Bnai Zion Medical Center, 47 Golomb Street, P.O.B. 4940, Haifa, 31048 Israel.
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