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Lu X, Luo C, Wu J, Deng Y, Mu X, Zhang T, Yang X, Liu Q, Li Z, Tang S, Hu Y, Du Q, Xu J, Xie R. Ion channels and transporters regulate nutrient absorption in health and disease. J Cell Mol Med 2023; 27:2631-2642. [PMID: 37638698 PMCID: PMC10494301 DOI: 10.1111/jcmm.17853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/03/2023] [Accepted: 07/06/2023] [Indexed: 08/29/2023] Open
Abstract
Ion channels and transporters are ubiquitously expressed on cell membrane, which involve in a plethora of physiological process such as contraction, neurotransmission, secretion and so on. Ion channels and transporters is of great importance to maintaining membrane potential homeostasis, which is essential to absorption of nutrients in gastrointestinal tract. Most of nutrients are electrogenic and require ion channels and transporters to absorb. This review summarizes the latest research on the role of ion channels and transporters in regulating nutrient uptake such as K+ channels, Ca2+ channels and ion exchangers. Revealing the mechanism of ion channels and transporters associated with nutrient uptake will be helpful to provide new methods to diagnosis and find potential targets for diseases like diabetes, inflammatory bowel diseases, etc. Even though some of study still remain ambiguous and in early stage, we believe that ion channels and transporters will be novel therapeutic targets in the future.
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Affiliation(s)
- Xianmin Lu
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Chen Luo
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Jiangbo Wu
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Ya Deng
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Xingyi Mu
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Ting Zhang
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Xiaoxu Yang
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Qi Liu
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Zhuo Li
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Siqi Tang
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Yanxia Hu
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Qian Du
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Jingyu Xu
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
| | - Rui Xie
- Department of GastroenterologyDigestive Disease Hospital, Affiliated Hospital of Zunyi Medical UniversityZunyiChina
- The Collaborative InnovAffiliated Hospital of Zunyi Medical Universityation Center of Tissue Damage Repair and Regeneration Medicine of Zunyi Medical UniversityZunyiChina
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Abid S, Bnouham M. A Review on Experimental Models to Test Medicinal Plants on Postprandial Blood Glucose in Diabetes. Curr Diabetes Rev 2023; 19:e080422203278. [PMID: 35400346 DOI: 10.2174/1573399818666220408100830] [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: 10/12/2021] [Revised: 12/07/2021] [Accepted: 01/31/2022] [Indexed: 11/22/2022]
Abstract
Due to the gravity of postprandial hyperglycemia in the development of microvascular and macrovascular diseases in diabetics, many medicinal plants are tested to determine their effectiveness in glycemic control and the mechanisms of action of the products. Consequently, various diabetic models have been developed and enhanced over the years. The objective of this review is to describe some of the experimental models to study the effect of medicinal plants used to control postprandial hyperglycemia. Data was collected from PubMed, ScienceDirect, Scopus, and Google scholar (1953-2021). Fiftyseven (57) studies were included in this review article. Ten models were identified and described. For each model, we described the targets involved and their roles in postprandial blood glucose control. The experimental design and procedures described the targets such as an α-glucosidase enzyme, SGLT1, GLUT2, DPP-IV, Na+/K+ ATPase pump, or intestinal motility in the models, experiment design and procedures were described. This review will facilitate the selection of the most appropriate model for studying agents used to investigate postprandial blood glucose.
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Affiliation(s)
- Sanae Abid
- Laboratory of Bio-Resources, Biotechnologies, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, University Mohamed Ist 60 000, Oujda, Morocco
| | - Mohamed Bnouham
- Laboratory of Bio-Resources, Biotechnologies, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, University Mohamed Ist 60 000, Oujda, Morocco
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Abstract
Nephrolithiasis is a worldwide problem with increasing prevalence, enormous costs, and significant morbidity. Calcium-containing kidney stones are by far the most common kidney stones encountered in clinical practice. Consequently, hypercalciuria is the greatest risk factor for kidney stone formation. Hypercalciuria can result from enhanced intestinal absorption, increased bone resorption, or altered renal tubular transport. Kidney stone formation is complex and driven by high concentrations of calcium-oxalate or calcium-phosphate in the urine. After discussing the mechanism mediating renal calcium salt precipitation, we review recent discoveries in renal tubular calcium transport from the proximal tubule, thick ascending limb, and distal convolution. Furthermore, we address how calcium is absorbed from the intestine and mobilized from bone. The effect of acidosis on bone calcium resorption and urinary calcium excretion is also considered. Although recent discoveries provide insight into these processes, much remains to be understood in order to provide improved therapies for hypercalciuria and prevent kidney stone formation. Expected final online publication date for the Annual Review of Physiology, Volume 84 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- R T Alexander
- Departments of Physiology and Pediatrics, University of Alberta, Edmonton, Canada; .,Membrane Protein Disease Research Group, University of Alberta, Edmonton, Canada
| | - D G Fuster
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - H Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
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Wongon M, Limpeanchob N. Artocarpus lacucha Extract and Oxyresveratrol Inhibit Glucose Transporters in Human Intestinal Caco-2 Cells. PLANTA MEDICA 2021; 87:709-715. [PMID: 33511623 DOI: 10.1055/a-1324-3570] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Reduction of intestinal glucose absorption might result from either delayed carbohydrate digestion or blockage of glucose transporters. Previously, oxyresveratrol was shown to inhibit α-glucosidase, but its effect on glucose transporters has not been explored. The present study aimed to assess oxyresveratrol-induced inhibition of the facilitative glucose transporter 2 and the active sodium-dependent glucose transporter 1. An aqueous extract of Artocarpus lacucha, Puag Haad, which is oxyresveratrol-enriched, was also investigated. Glucose transport was measured by uptake into Caco-2 cells through either glucose transporter 2 or sodium-dependent glucose transporter 1 according to the culture conditions. Oxyresveratrol (40 to 800 µM) dose-dependently reduced glucose transport, which appeared to inhibit both glucose transporter 2 and sodium-dependent glucose transporter 1. Puag Haad at similar concentrations also inhibited these transporters but with greater efficacy. Oxyresveratrol and Puag Haad could help reduce postprandial hyperglycemic peaks, which are considered to be most damaging in diabetics.
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Affiliation(s)
- Matusorn Wongon
- Department of Pharmacy Practice and Center of Excellence for Innovation in Chemistry, Pharmacological Research Unit, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand
| | - Nanteetip Limpeanchob
- Department of Pharmacy Practice and Center of Excellence for Innovation in Chemistry, Pharmacological Research Unit, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, Thailand
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Zhang F, Wan H, Chu F, Lu C, Chen J, Dong H. Small intestinal glucose and sodium absorption through calcium-induced calcium release and store-operated Ca 2+ entry mechanisms. Br J Pharmacol 2020; 178:346-362. [PMID: 33080043 DOI: 10.1111/bph.15287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 08/27/2020] [Accepted: 10/06/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE Luminal glucose enhances intestinal Ca2+ absorption through apical Cav 1.3 channels necessary for GLUT2-mediated glucose absorption. As these reciprocal mechanisms are not well understood, we investigated the regulatory mechanisms of intestinal [Ca2+ ]cyt and SGLT1-mediated Na+ -glucose co-transports. EXPERIMENTAL APPROACH Glucose absorption and channel expression were examined in mouse upper jejunal epithelium using an Ussing chamber, immunocytochemistry and Ca2+ and Na+ imaging in single intestinal epithelial cells. KEY RESULTS Glucose induced jejunal Isc via Na+ -glucose cotransporter 1 (SGLT1) operated more efficiently in the presence of extracellular Ca2+ . A crosstalk between luminal Ca2+ entry via plasma Cav 1.3 channels and the ER Ca2+ release through ryanodine receptor (RYR) activation in small intestinal epithelial cell (IEC) or Ca2+ -induced Ca2+ release (CICR) mechanism was involve in Ca2+ -mediated jejunal glucose absorption. The ER Ca2+ release through RyR triggered basolateral Ca2+ entry or store-operated Ca2+ entry (SOCE) mechanism and the subsequent Ca2+ entry via Na+ /Ca2+ exchanger 1 (NCX1) were found to be critical in Na+ -glucose cotransporter-mediated glucose absorption. Blocking RyR, SOCE and NCX1 inhibited glucose induced [Na+ ]cyt and [Ca2+ ]cyt in single IEC and protein expression and co-localization of STIM1/Orai1, RyR1 and NCX1 were detected in IEC and jejunal mucosa. CONCLUSION AND IMPLICATIONS Luminal Ca2+ influx through Cav 1.3 triggers the CICR through RyR1 to deplete the ER Ca2+ , which induces the basolateral STIM1/Orai1-mediated SOCE mechanism and the subsequent Ca2+ entry via NCX1 to regulate intestinal glucose uptake via Ca2+ signalling. Targeting these mechanisms in IEC may help to modulate blood glucose and sodium in the metabolic disease.
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Affiliation(s)
- Fenglian Zhang
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hanxing Wan
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Fenglan Chu
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Cheng Lu
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Jun Chen
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hui Dong
- Department of Gastroenterology, Xinqiao Hospital, Army Medical University, Chongqing, China.,Department of Medicine, School of Medicine, University of California, San Diego, CA, USA
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Narang BJ, Wallis GA, Gonzalez JT. The effect of calcium co-ingestion on exogenous glucose oxidation during endurance exercise in healthy men: A pilot study. Eur J Sport Sci 2020; 21:1156-1164. [DOI: 10.1080/17461391.2020.1813336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Gareth A. Wallis
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
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Koepsell H. Glucose transporters in the small intestine in health and disease. Pflugers Arch 2020; 472:1207-1248. [PMID: 32829466 PMCID: PMC7462918 DOI: 10.1007/s00424-020-02439-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/11/2020] [Accepted: 07/17/2020] [Indexed: 12/23/2022]
Abstract
Absorption of monosaccharides is mainly mediated by Na+-D-glucose cotransporter SGLT1 and the facititative transporters GLUT2 and GLUT5. SGLT1 and GLUT2 are relevant for absorption of D-glucose and D-galactose while GLUT5 is relevant for D-fructose absorption. SGLT1 and GLUT5 are constantly localized in the brush border membrane (BBM) of enterocytes, whereas GLUT2 is localized in the basolateral membrane (BLM) or the BBM plus BLM at low and high luminal D-glucose concentrations, respectively. At high luminal D-glucose, the abundance SGLT1 in the BBM is increased. Hence, D-glucose absorption at low luminal glucose is mediated via SGLT1 in the BBM and GLUT2 in the BLM whereas high-capacity D-glucose absorption at high luminal glucose is mediated by SGLT1 plus GLUT2 in the BBM and GLUT2 in the BLM. The review describes functions and regulations of SGLT1, GLUT2, and GLUT5 in the small intestine including diurnal variations and carbohydrate-dependent regulations. Also, the roles of SGLT1 and GLUT2 for secretion of enterohormones are discussed. Furthermore, diseases are described that are caused by malfunctions of small intestinal monosaccharide transporters, such as glucose-galactose malabsorption, Fanconi syndrome, and fructose intolerance. Moreover, it is reported how diabetes, small intestinal inflammation, parental nutrition, bariatric surgery, and metformin treatment affect expression of monosaccharide transporters in the small intestine. Finally, food components that decrease D-glucose absorption and drugs in development that inhibit or downregulate SGLT1 in the small intestine are compiled. Models for regulations and combined functions of glucose transporters, and for interplay between D-fructose transport and metabolism, are discussed.
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Affiliation(s)
- Hermann Koepsell
- Institute for Anatomy and Cell Biology, University of Würzburg, Koellikerstr 6, 97070, Würzburg, Germany.
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Romanet S, Aschenbach JR, Pieper R, Zentek J, Htoo JK, Whelan RA, Mastrototaro L. Dietary Supplementation of dl-Methionine Potently Induces Sodium-Dependent l-Methionine Absorption in Porcine Jejunum Ex Vivo. J Nutr 2020; 150:1782-1789. [PMID: 32359147 DOI: 10.1093/jn/nxaa115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/21/2020] [Accepted: 04/01/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Methionine is an essential amino acid (AA) with many fundamental roles. Humans often supplement l-Met, whereas dl-Met and dl-2-hydroxy-4-(methylthio)butanoic acid (dl-HMTBA) are more frequently used to supplement livestock. OBJECTIVES The study aimed to investigate whether dietary Met source alters the absorptive capacity for Met isomers in the small intestine of piglets. METHODS A total of 27 male 10-wk-old piglets in 3 feeding groups received a diet supplemented with 0.21% dl-Met, 0.21% l-Met, or 0.31% dl-HMTBA to meet the Met + cystine requirement. After ≥10 d, absorptive fluxes of d-Met or l-Met were measured at a physiological concentration of 50 μM and a high concentration of 5 mM in duodenum, middle jejunum, and ileum ex vivo. Data were compared by 2-factor ANOVA. RESULTS Across diets, fluxes of both Met isomers at both tested concentrations increased from duodenum to ileum by a factor of ∼2-5.5 (P < 0.05). Pigs supplemented with dl-Met had greater (P < 0.085) absorptive fluxes at 50 μM l-Met (0.50, 2.07, and 3.86 nmol · cm-2 · h-1) and d-Met (0.62, 1.41, and 1.19 nmol · cm-2 · h-1) than did pigs supplemented with dl-HMTBA (l-Met: 0.28, 0.76, and 1.08 nmol · cm-2 · h-1; d-Met: 0.34, 0.58, and 0.64 nmol · cm-2 · h-1) in duodenum, jejunum, and ileum, respectively. Only in jejunum of dl-Met-fed pigs, fluxes at 50 μM l-Met were reduced by the omission of luminal Na+ (from 3.27 to 0.86 nmol · cm-2 · h-1; P < 0.05) and by a cocktail of 22 luminal AAs (to 1.05 nmol · cm-2 · h-1; P < 0.05). CONCLUSIONS Dietary supplementation of dl-Met increases the efficiency of l-Met and d-Met absorption at physiologically relevant luminal Met concentrations along the small intestine of pigs, including a very prominent induction of an Na+-dependent transport system with preference for l-Met in the mid-jejunum. Dietary supplementation with dl-Met could be a promising tool to improve the absorption of Met and other AAs.
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Affiliation(s)
- Stella Romanet
- Institute of Veterinary Physiology, Freie Universtität Berlin, Berlin, Germany
| | - Jörg R Aschenbach
- Institute of Veterinary Physiology, Freie Universtität Berlin, Berlin, Germany
| | - Robert Pieper
- Institute of Animal Nutrition, Freie Universtität Berlin, Berlin, Germany
| | - Jürgen Zentek
- Institute of Animal Nutrition, Freie Universtität Berlin, Berlin, Germany
| | - John K Htoo
- Animal Nutrition Services, Evonik Nutrition & Care GmbH, Hanau-Wolfgang, Germany
| | - Rose A Whelan
- Animal Nutrition Services, Evonik Nutrition & Care GmbH, Hanau-Wolfgang, Germany
| | - Lucia Mastrototaro
- Institute of Veterinary Physiology, Freie Universtität Berlin, Berlin, Germany
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Wilkens MR, Nelson CD, Hernandez LL, McArt JA. Symposium review: Transition cow calcium homeostasis—Health effects of hypocalcemia and strategies for prevention. J Dairy Sci 2020; 103:2909-2927. [DOI: 10.3168/jds.2019-17268] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/18/2019] [Indexed: 12/14/2022]
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Kaji I. Dynamics of Intestinal Calcium Absorption in Neonates. Cell Mol Gastroenterol Hepatol 2019; 8:647-648. [PMID: 31536717 PMCID: PMC6889640 DOI: 10.1016/j.jcmgh.2019.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 08/20/2019] [Accepted: 08/23/2019] [Indexed: 12/10/2022]
Affiliation(s)
- Izumi Kaji
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee.
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Wongdee K, Rodrat M, Teerapornpuntakit J, Krishnamra N, Charoenphandhu N. Factors inhibiting intestinal calcium absorption: hormones and luminal factors that prevent excessive calcium uptake. J Physiol Sci 2019; 69:683-696. [PMID: 31222614 PMCID: PMC10717634 DOI: 10.1007/s12576-019-00688-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/09/2019] [Indexed: 12/11/2022]
Abstract
Besides the two canonical calciotropic hormones, namely parathyroid hormone and 1,25-dihydroxyvitamin D [1,25(OH)2D3], there are several other endocrine and paracrine factors, such as prolactin, estrogen, and insulin-like growth factor that have been known to directly stimulate intestinal calcium absorption. Generally, to maintain an optimal plasma calcium level, these positive regulators enhance calcium absorption, which is indirectly counterbalanced by a long-loop negative feedback mechanism, i.e., through calcium-sensing receptor in the parathyroid chief cells. However, several lines of recent evidence have revealed the presence of calcium absorption inhibitors present in the intestinal lumen and extracellular fluid in close vicinity to enterocytes, which could also directly compromise calcium absorption. For example, luminal iron, circulating fibroblast growth factor (FGF)-23, and stanniocalcin can decrease calcium absorption, thereby preventing excessive calcium uptake under certain conditions. Interestingly, the intestinal epithelial cells themselves could lower their rate of calcium uptake after exposure to high luminal calcium concentration, suggesting a presence of an ultra-short negative feedback loop independent of systemic hormones. The existence of neural regulation is also plausible but this requires more supporting evidence. In the present review, we elaborate on the physiological significance of these negative feedback regulators of calcium absorption, and provide evidence to show how our body can efficiently restrict a flood of calcium influx in order to maintain calcium homeostasis.
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Affiliation(s)
- Kannikar Wongdee
- Faculty of Allied Health Sciences, Burapha University, Chonburi, Thailand
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Mayuree Rodrat
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Jarinthorn Teerapornpuntakit
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Nateetip Krishnamra
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.
- The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, Thailand.
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Selle P, Liu SY. The Relevance of Starch and Protein Digestive Dynamics in Poultry. J APPL POULTRY RES 2019. [DOI: 10.3382/japr/pfy026] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Beggs MR, Lee JJ, Busch K, Raza A, Dimke H, Weissgerber P, Engel J, Flockerzi V, Alexander RT. TRPV6 and Ca v1.3 Mediate Distal Small Intestine Calcium Absorption Before Weaning. Cell Mol Gastroenterol Hepatol 2019; 8:625-642. [PMID: 31398491 PMCID: PMC6889763 DOI: 10.1016/j.jcmgh.2019.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/15/2019] [Accepted: 07/17/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Intestinal Ca2+ absorption early in life is vital to achieving optimal bone mineralization. The molecular details of intestinal Ca2+ absorption have been defined in adults after peak bone mass is obtained, but they are largely unexplored during development. We sought to delineate the molecular details of transcellular Ca2+ absorption during this critical period. METHODS Expression of small intestinal and renal calcium transport genes was assessed by using quantitative polymerase chain reaction. Net calcium flux across small intestinal segments was measured in Ussing chambers, including after pharmacologic inhibition or genetic manipulation of TRPV6 or Cav1.3 calcium channels. Femurs were analyzed by using micro-computed tomography and histology. RESULTS Net TRPV6-mediated Ca2+ flux across the duodenum was absent in pre-weaned (P14) mice but present after weaning. In contrast, we found significant transcellular Ca2+ absorption in the jejunum at 2 weeks but not 2 months of age. Net jejunal Ca2+ absorption observed at P14 was not present in either Trpv6 mutant (D541A) mice or Cav1.3 knockout mice. We observed significant nifedipine-sensitive transcellular absorption across the ileum at P14 but not 2 months. Cav1.3 knockout pups exhibited delayed bone mineral accrual, compensatory nifedipine-insensitive Ca2+ absorption in the ileum, and increased expression of renal Ca2+ reabsorption mediators at P14. Moreover, weaning pups at 2 weeks reduced jejunal and ileal Cav1.3 expression. CONCLUSIONS We have detailed novel pathways contributing to transcellular Ca2+ transport across the distal small intestine of mice during development, highlighting the complexity of the multiple mechanisms involved in achieving a positive Ca2+ balance early in life.
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Affiliation(s)
- Megan R. Beggs
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada,The Women’s & Children’s Health Research Institute, Edmonton, Alberta, Canada
| | - Justin J. Lee
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada,The Women’s & Children’s Health Research Institute, Edmonton, Alberta, Canada
| | - Kai Busch
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, Homburg, Germany
| | - Ahsan Raza
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, Homburg, Germany
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Petra Weissgerber
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, Homburg, Germany
| | - Jutta Engel
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine (CIPMM), Saarland University, School of Medicine, Homburg, Germany
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Saarland University, Homburg, Germany
| | - R. Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada,The Women’s & Children’s Health Research Institute, Edmonton, Alberta, Canada,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada,Correspondence Address correspondence to: R. Todd Alexander, MD, PhD, Department of Pediatrics, 4-585 Edmonton Clinic Health Academy, 11405 – 87 Avenue, University of Alberta, Edmonton, Alberta T6G 2R7, Canada. fax: (780) 248-5556.
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14
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Xie B, Wang P, Yan Z, Ren Y, Dong K, Song Z, Zhang J, Zhang C. Growth performance, nutrient digestibility, carcass traits, body composition, and meat quality of goat fed Chinese jujube (Ziziphus Jujuba Mill) fruit as a replacement for maize in diet. Anim Feed Sci Technol 2018. [DOI: 10.1016/j.anifeedsci.2018.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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15
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Müller U, Stübl F, Schwarzinger B, Sandner G, Iken M, Himmelsbach M, Schwarzinger C, Ollinger N, Stadlbauer V, Höglinger O, Kühne T, Lanzerstorfer P, Weghuber J. In Vitro and In Vivo Inhibition of Intestinal Glucose Transport by Guava (Psidium Guajava) Extracts. Mol Nutr Food Res 2018; 62:e1701012. [PMID: 29688623 PMCID: PMC6001447 DOI: 10.1002/mnfr.201701012] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 03/15/2018] [Indexed: 12/21/2022]
Abstract
SCOPE Known pharmacological activities of guava (Psidium guajava) include modulation of blood glucose levels. However, mechanistic details remain unclear in many cases. METHODS AND RESULTS This study investigated the effects of different guava leaf and fruit extracts on intestinal glucose transport in vitro and on postprandial glucose levels in vivo. Substantial dose- and time-dependent glucose transport inhibition (up to 80%) was observed for both guava fruit and leaf extracts, at conceivable physiological concentrations in Caco-2 cells. Using sodium-containing (both glucose transporters, sodium-dependent glucose transporter 1 [SGLT1] and glucose transporter 2 [GLUT2], are active) and sodium-free (only GLUT2 is active) conditions, we show that inhibition of GLUT2 was greater than that of SGLT1. Inhibitory properties of guava extracts also remained stable after digestive juice treatment, indicating a good chemical stability of the active substances. Furthermore, we could unequivocally show that guava extracts significantly reduced blood glucose levels (≈fourfold reduction) in a time-dependent manner in vivo (C57BL/6N mice). Extracts were characterized with respect to their main putative bioactive compounds (polyphenols) using HPLC and LC-MS. CONCLUSION The data demonstrated that guava leaf and fruit extracts can potentially contribute to the regulation of blood glucose levels.
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Affiliation(s)
- Ulrike Müller
- University of Applied Sciences Upper Austria4600WelsAustria
| | - Flora Stübl
- University of Applied Sciences Upper Austria4600WelsAustria
| | - Bettina Schwarzinger
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
| | - Georg Sandner
- University of Applied Sciences Upper Austria4600WelsAustria
| | | | - Markus Himmelsbach
- Johannes Kepler UniversityInstitute for Analytical Chemistry4040LinzAustria
| | - Clemens Schwarzinger
- Johannes Kepler UniversityInstitute for Chemical Technology of Organic Materials4040LinzAustria
| | - Nicole Ollinger
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
| | - Verena Stadlbauer
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
| | | | | | | | - Julian Weghuber
- University of Applied Sciences Upper Austria4600WelsAustria
- Austrian Competence Center for Feed and Food QualitySafety and Innovation4600WelsAustria
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16
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Fiscaletti M, Lebel MJ, Alos N, Benoit G, Jantchou P. Two Cases of Mistaken Polyuria and Nephrocalcinosis in Infants with Glucose-Galactose Malabsorption: A Possible Role of 1,25(OH)2D3
. Horm Res Paediatr 2018; 87:277-282. [PMID: 28152538 DOI: 10.1159/000454951] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 12/01/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND/AIMS Glucose-galactose malabsorption (GGM) is a rare and potentially fatal disorder. The autosomal recessive mutation of the SGLT1 gene interferes with the active glucose transport in the gut resulting in osmotic diarrhea and failure to thrive (FTT). Two nonrelated infants with GGM are presented as well as a novel mutation in SGLT1. CASE PRESENTATION The first case consulted for FTT and presented with hypercalcemia and hypercalciuria. His mother had self-medicated with high doses of vitamin D. The second case consulted for macroscopic hematuria, and presented with dehydration and secondary acute kidney injury. In both cases, the profuse diarrhea, initially mistaken for polyuria, promptly resolved after the introduction of glucose-galactose-free milk. Investigations showed bilateral nephrocalcinosis and high levels of 1,25(OH)2D3 in both patients. We hypothesize that the upregulation of epithelial calcium channels (TRPV6) and 1,25(OH)2D3 are possible factors involved in the pathophysiology of nephrocalcinosis sometimes seen in GGM. Furthermore, a novel intronic SGLT1 mutation (c.207+2dup) is described. CONCLUSION These 2 cases demonstrate that a malabsorption disorder such as GGM can present with nephrocalcinosis and/or hypercalcemia, with increased 1,25(OH)2D3 levels in infants. Prompt recognition of GGM is sometimes difficult but crucial.
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Affiliation(s)
- Melissa Fiscaletti
- Sainte Justine University Health Center, University of Montreal, Montreal, Québec, Canada
| | - Marie-Jeanne Lebel
- Sainte Justine University Health Center, University of Montreal, Montreal, Québec, Canada
| | - Nathalie Alos
- Sainte Justine University Health Center, University of Montreal, Montreal, Québec, Canada.,Research Center of Sainte Justine Health Center, Montreal, Québec, Canada
| | - Geneviève Benoit
- Sainte Justine University Health Center, University of Montreal, Montreal, Québec, Canada
| | - Prévost Jantchou
- Sainte Justine University Health Center, University of Montreal, Montreal, Québec, Canada.,Research Center of Sainte Justine Health Center, Montreal, Québec, Canada
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17
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Gauer JS, Tumova S, Lippiat JD, Kerimi A, Williamson G. Differential patterns of inhibition of the sugar transporters GLUT2, GLUT5 and GLUT7 by flavonoids. Biochem Pharmacol 2018; 152:11-20. [PMID: 29548810 DOI: 10.1016/j.bcp.2018.03.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/09/2018] [Indexed: 11/16/2022]
Abstract
Only limited data are available on the inhibition of the sugar transporter GLUT5 by flavonoids or other classes of bioactives. Intestinal GLUT7 is poorly characterised and no information exists concerning its inhibition. We aimed to study the expression of GLUT7 in Caco-2/TC7 intestinal cells, and evaluate inhibition of glucose transport by GLUT2 and GLUT7, and of fructose transport by GLUT2, GLUT5 and GLUT7, by flavonoids. Differentiated Caco-2/TC7 cell monolayers were used to investigate GLUT7 expression, as well as biotinylation and immunofluorescence to assess GLUT7 location. For mechanistic sugar transport studies, X. laevis oocytes were injected with individual mRNA, and GLUT protein expression on oocyte membranes was confirmed. Oocytes were incubated with D-[14C(U)]-glucose or D-[14C(U)]-fructose in the presence of flavonoids, and uptake was estimated by liquid scintilation counting. In differentiated Caco-2/TC7 cell monolayers, GLUT7 was mostly expressed apically. When applied apically, or to both compartments, sorbitol, galactose, L-glucose or sucrose did not affect GLUT7 mRNA expression. Fructose applied to both sides increased GLUT7 mRNA (13%, p ≤ 0.001) and total GLUT7 protein (2.7-fold, p ≤ 0.05), while the ratio between apical, basolateral and total GLUT7 protein was unchanged. In the X. laevis oocyte model, GLUT2-mediated glucose and fructose transport were inhibited by quercetin, (-)-epigallocatechin gallate (EGCG) and apigenin, GLUT5-mediated fructose transport was inhibited by apigenin and EGCG, but not by quercetin, and GLUT7-mediated uptake of both glucose and fructose was inhibited by apigenin, but not by quercetin nor EGCG. Expression of GLUT7 was increased by fructose, but only when applied to Caco-2/TC7 cells both apically and basolaterally. Since GLUT2, GLUT5 and GLUT7 show different patterns of inhibition by the tested flavonoids, we suggest that they have the potential to be used as investigational tools to distinguish sugar transporter activity in different biological settings.
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Affiliation(s)
- Julia S Gauer
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
| | - Sarka Tumova
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Asimina Kerimi
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK
| | - Gary Williamson
- School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, UK.
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18
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Moss AF, Liu SY, Selle PH. Progress in comprehending the phytate–phytase axis in chicken-meat production. ANIMAL PRODUCTION SCIENCE 2018. [DOI: 10.1071/an17594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
After an extended delay, the level of acceptance of exogenous phytases by the global chicken-meat industry is now almost complete. Contemporary bacterial phytases degrade phytate primarily in the gizzard. The extent of phytate degradation determines the extent to which phytate-bound phosphorus (P) is liberated; however, studies designed to investigate phytate degradation along the digestive tract have generated some confusing outcomes. This may be related to the reactivity of the phytate moiety, coupled with problems with inert dietary markers and perhaps a lack of complete and uniform extractions of phytate from digesta due to variations in digesta pH and phytate solubility. Quite recently, phytase was shown to have profound impacts on sodium (Na) digestibility coefficients in four segments of the small intestine. This has obvious implications for intestinal uptakes of glucose and amino acids via their respective Na+-dependent transport systems and it is possible that phytate and phytase have reciprocal impacts on ‘sodium pump’ (Na+, K+-ATPase) activity. It has been recently demonstrated unequivocally that phytase has the capacity to increase amino acid digestibility coefficients to the extent that phytase may generate a ‘proximal shift’ in the sites of amino acid absorption. The impact of phytase on starch digestibility is more equivocal and phytase responses may stem more from enhanced glucose absorption rather than starch digestion. The acceptance of phytase is hardly surprising, given its capacity to increase P utilisation coupled with numerous other positive influences that are still being properly realised.
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19
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Thammayon N, Wongdee K, Lertsuwan K, Suntornsaratoon P, Thongbunchoo J, Krishnamra N, Charoenphandhu N. Na +/H + exchanger 3 inhibitor diminishes the amino-acid-enhanced transepithelial calcium transport across the rat duodenum. Amino Acids 2016; 49:725-734. [PMID: 27981415 DOI: 10.1007/s00726-016-2374-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/29/2016] [Indexed: 12/22/2022]
Abstract
Na+/H+ exchanger (NHE)-3 is important for intestinal absorption of nutrients and minerals, including calcium. The previous investigations have shown that the intestinal calcium absorption is also dependent on luminal nutrients, but whether aliphatic amino acids and glucose, which are abundant in the luminal fluid during a meal, similarly enhance calcium transport remains elusive. Herein, we used the in vitro Ussing chamber technique to determine epithelial electrical parameters, i.e., potential difference (PD), short-circuit current (Isc), and transepithelial resistance, as well as 45Ca flux in the rat duodenum directly exposed on the mucosal side to glucose or various amino acids. We found that mucosal glucose exposure led to the enhanced calcium transport, PD, and Isc, all of which were insensitive to NHE3 inhibitor (100 nM tenapanor). In the absence of mucosal glucose, several amino acids (12 mM in the mucosal side), i.e., alanine, isoleucine, leucine, proline, and hydroxyproline, markedly increased the duodenal calcium transport. An inhibitor for NHE3 exposure on the mucosal side completely abolished proline- and leucine-enhanced calcium transport, but not transepithelial transport of both amino acids themselves. In conclusion, glucose and certain amino acids in the mucosal side were potent stimulators of the duodenal calcium absorption, but only amino-acid-enhanced calcium transport was NHE3-dependent.
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Affiliation(s)
- Nithipak Thammayon
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Kannikar Wongdee
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Faculty of Allied Health Sciences, Burapha University, Chonburi, 20131, Thailand
| | - Kornkamon Lertsuwan
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Department of Biochemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand
| | - Panan Suntornsaratoon
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Jirawan Thongbunchoo
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Nateetip Krishnamra
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Narattaphol Charoenphandhu
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok, 10400, Thailand. .,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. .,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, 73170, Thailand.
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20
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Dotimas JR, Lee AW, Schmider AB, Carroll SH, Shah A, Bilen J, Elliott KR, Myers RB, Soberman RJ, Yoshioka J, Lee RT. Diabetes regulates fructose absorption through thioredoxin-interacting protein. eLife 2016; 5. [PMID: 27725089 PMCID: PMC5059142 DOI: 10.7554/elife.18313] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/01/2016] [Indexed: 01/17/2023] Open
Abstract
Metabolic studies suggest that the absorptive capacity of the small intestine for fructose is limited, though the molecular mechanisms controlling this process remain unknown. Here we demonstrate that thioredoxin-interacting protein (Txnip), which regulates glucose homeostasis in mammals, binds to fructose transporters and promotes fructose absorption by the small intestine. Deletion of Txnip in mice reduced fructose transport into the peripheral bloodstream and liver, as well as the severity of adverse metabolic outcomes resulting from long-term fructose consumption. We also demonstrate that fructose consumption induces expression of Txnip in the small intestine. Diabetic mice had increased expression of Txnip in the small intestine as well as enhanced fructose uptake and transport into the hepatic portal circulation. The deletion of Txnip in mice abolished the diabetes-induced increase in fructose absorption. Our results indicate that Txnip is a critical regulator of fructose metabolism and suggest that a diabetic state can promote fructose uptake.
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Affiliation(s)
- James R Dotimas
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Austin W Lee
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Angela B Schmider
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Charlestown, United States
| | - Shannon H Carroll
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Anu Shah
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Julide Bilen
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Kayla R Elliott
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Ronald B Myers
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Roy J Soberman
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Charlestown, United States.,Molecular Imaging Core, Massachusetts General Hospital, Charlestown, United States
| | - Jun Yoshioka
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
| | - Richard T Lee
- Department of Stem Cell and Regenerative Biology, Harvard University, Harvard Stem Cell Institute, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, United States
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21
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Fothergill LJ, Callaghan B, Rivera LR, Lieu T, Poole DP, Cho HJ, Bravo DM, Furness JB. Effects of Food Components That Activate TRPA1 Receptors on Mucosal Ion Transport in the Mouse Intestine. Nutrients 2016; 8:nu8100623. [PMID: 27735854 PMCID: PMC5084011 DOI: 10.3390/nu8100623] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 11/16/2022] Open
Abstract
TRPA1 is a ligand-activated cation channel found in the intestine and other tissues. Components of food that stimulate TRPA1 receptors (phytonutrients) include allyl isothiocyanate, cinnamaldehyde and linalool, but these may also act at other receptors. Cells lining the intestinal mucosa are immunoreactive for TRPA1 and Trpa1 mRNA occurs in mucosal extracts, suggesting that the TRPA1 receptor is the target for these agonists. However, in situ hybridisation reveals Trpa1 expression in 5-HT containing enteroendocrine cells, not enterocytes. TRPA1 agonists evoke mucosal secretion, which may be indirect (through release of 5-HT) or direct by activation of enterocytes. We investigated effects of the phytonutrients on transmucosal ion currents in mouse duodenum and colon, and the specificity of the phytonutrients in cells transfected with Trpa1, and in Trpa1-deficient mice. The phytonutrients increased currents in the duodenum with the relative potencies: allyl isothiocyanate (AITC) > cinnamaldehyde > linalool (0.1 to 300 μM). The rank order was similar in the colon, but linalool was ineffective. Responses to AITC were reduced by the TRPA1 antagonist HC-030031 (100 μM), and were greatly diminished in Trpa1−/− duodenum and colon. Responses were not reduced by tetrodotoxin, 5-HT receptor antagonists, or atropine, but inhibition of prostaglandin synthesis reduced responses. Thus, functional TRPA1 channels are expressed by enterocytes of the duodenum and colon. Activation of enterocyte TRPA1 by food components has the potential to facilitate nutrient absorption.
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Affiliation(s)
- Linda J Fothergill
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville VIC 3010, Australia.
| | - Brid Callaghan
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville VIC 3010, Australia.
| | - Leni R Rivera
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville VIC 3010, Australia.
- Metabolic Research Unit, School of Medicine, Deakin University, Geelong VIC 3216, Australia.
| | - TinaMarie Lieu
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville VIC 3052, Australia.
| | - Daniel P Poole
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville VIC 3010, Australia.
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville VIC 3052, Australia.
| | - Hyun-Jung Cho
- Biological Optical Microscopy Platform, University of Melbourne, Parkville VIC 3010, Australia.
| | - David M Bravo
- In Vivo Animal Nutrition & Health, Talhouët, Saint-Nolff 56250, France.
| | - John B Furness
- Department of Anatomy & Neuroscience, University of Melbourne, Parkville VIC 3010, Australia.
- Florey Institute of Neuroscience and Mental Health, Parkville VIC 3010, Australia.
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22
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Klinger S, Schröder B, Gemmer A, Reimers J, Breves G, Herrmann J, Wilkens MR. Gastrointestinal transport of calcium and glucose in lactating ewes. Physiol Rep 2016; 4:4/11/e12817. [PMID: 27273883 PMCID: PMC4908493 DOI: 10.14814/phy2.12817] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/29/2016] [Indexed: 01/26/2023] Open
Abstract
During lactation, mineral and nutrient requirements increase dramatically, particularly those for Ca and glucose. In contrast to monogastric species, in ruminants, it is rather unclear to which extend this physiological change due to increased demand for milk production is accompanied by functional adaptations of the gastrointestinal tract (GIT). Therefore, we investigated potential modulations of Ca and glucose transport mechanisms in the GIT of lactating and dried‐off sheep. Ussing‐chamber technique was applied to determine the ruminal and jejunal Ca flux rates. In the jejunum, electrophysiological properties in response to glucose were recorded. Jejunal brush‐border membrane vesicles (BBMV) served to characterize glucose uptake via sodium‐linked glucose transporter 1 (SGLT1), and RNA and protein expression levels of Ca and glucose transporting systems were determined. Ruminal Ca flux rate data showed a trend for higher absorption in lactating sheep. In the jejunum, small Ca absorption could only be observed in lactating ewes. From the results, it may be assumed that lactating ewes compensate for the Ca loss by increasing bone mobilization rather than by increasing supply through absorption from the GIT. Presence of SGLT1 in the jejunum of both groups was shown by RNA and protein identification, but glucose uptake into BBMV could only be detected in lactating sheep. This, however, could not be attributed to electrogenic glucose absorption in lactating sheep under Ussing‐chamber conditions, providing evidence that changes in jejunal glucose uptake may include additional factors, that is, posttranslational modifications such as phosphorylation.
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Affiliation(s)
- Stefanie Klinger
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Bernd Schröder
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Anja Gemmer
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Julia Reimers
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Gerhard Breves
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Jens Herrmann
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Mirja R Wilkens
- Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
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23
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Morimoto M, Azuma N, Kadowaki H, Abe T, Suto Y. Regulation of type 2 diabetes by helminth-induced Th2 immune response. J Vet Med Sci 2016; 78:1855-1864. [PMID: 27665994 PMCID: PMC5240765 DOI: 10.1292/jvms.16-0183] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Helminth-induced type 2 cytokines increase the number of regulatory T cells and
alternatively activated macrophages, resulting in modulation of the host–immune system.
Studies on these parasite-induced immunoregulatory mechanisms might contribute to the
development of new therapies for inflammatory diseases, including type 2 diabetes (T2D).
Previous studies have suggested that progression of obesity-associated metabolic
abnormalities is under pathophysiological control of CD4+ T cells. Glucose absorption
through the intestinal epithelium reduced after infection in a STAT-6-dependent manner. In
this study, we investigated whether infection with the gastrointestinal nematode parasite
Heligmosomoides polygyrus (Hp) can modulate T2D-associated pathology in
a mouse model (KK-Ay/TaJcl). KK-Ay/TaJcl mice were inoculated with infective third-stage
Hp larvae and studied at Day 8 following infection. Uninfected KK-Ay/TaJcl mice showed
high blood glucose levels even 120 min after administration of glucose by IP injection.
However, it was significantly improved in the infected group. HOMA-IR, fat accumulation
and FAS gene expression in the liver were significantly decreased by Hp infection. GLUT2
gene expression in this group was significantly lower than that in the uninfected diabetic
mice, which might be related to the decrease in glucose absorption in the
parasite-infected intestine. In conclusion, helminth-induced type 2 immune responses might
contribute to T2D disease control.
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Affiliation(s)
- Motoko Morimoto
- School of Food, Agricultural, and Environmental Sciences, Miyagi University, Sendai City, Miyagi 982-0215, Japan
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24
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López-Yoldi M, Castilla-Madrigal R, Lostao MP, Barber A, Prieto J, Martínez JA, Bustos M, Moreno-Aliaga MJ. Cardiotrophin-1 decreases intestinal sugar uptake in mice and in Caco-2 cells. Acta Physiol (Oxf) 2016; 217:217-26. [PMID: 26972986 DOI: 10.1111/apha.12674] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 10/12/2015] [Accepted: 03/04/2016] [Indexed: 12/15/2022]
Abstract
AIM Cardiotrophin-1 (CT-1) is a member of the IL-6 family of cytokines with a key role in glucose and lipid metabolism. In the current investigation, we examined the in vivo and in vitro effects of CT-1 treatment on intestinal sugar absorption in different experimental models. METHODS rCT-1 effects on α-Methyl-D-glucoside uptake were assessed in everted intestinal rings from wild-type and CT-1(-/-) mice and in Caco-2 cells. rCT-1 actions on SGLT-1 expression in brush border membrane vesicles and the identification of the potential signalling pathways involved were determined by Western blot. RESULTS In vivo administration (0.2 mg kg(-1) ) of rCT-1 caused a significant decrease on α-Methyl-D-glucoside uptake in everted intestinal rings from wild-type and CT-1(-/-) mice after short-term and long-term treatments. Similarly, in vitro treatment (1-50 ng mL(-1) ) with rCT-1 reduced α-Methyl-D-glucoside uptake in everted intestinal rings. In Caco-2 cells, rCT-1 treatment (20 ng mL(-1) , 1 and 24 h) lowered apical uptake of α-Methyl-D-glucoside in parallel with a decrease on SGLT-1 protein expression. rCT-1 promoted the phosphorylation of STAT-3 after 5 and 15 min treatment, but inhibited the activation by phosphorylation of AMPK after 30 and 60 min. Interestingly, pre-treatment with the JAK/STAT inhibitor (AG490) and with the AMPK activator (AICAR) reversed the inhibitory effects of rCT-1 on α-Methyl-D-glucoside uptake. AICAR also prevented the inhibition of SGLT-1 observed in rCT-1-treated cells. CONCLUSIONS CT-1 inhibits intestinal sugar absorption by the reduction of SGLT-1 levels through the AMPK pathway, which could also contribute to explain the hypoglycaemic and anti-obesity properties of CT-1.
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Affiliation(s)
- M. López-Yoldi
- Department of Nutrition, Food Science and Physiology; University of Navarra; Pamplona Navarra Spain
- Centre for Nutrition Research; University of Navarra; Pamplona Navarra Spain
| | - R. Castilla-Madrigal
- Department of Nutrition, Food Science and Physiology; University of Navarra; Pamplona Navarra Spain
- Centre for Nutrition Research; University of Navarra; Pamplona Navarra Spain
| | - M. P. Lostao
- Department of Nutrition, Food Science and Physiology; University of Navarra; Pamplona Navarra Spain
- Centre for Nutrition Research; University of Navarra; Pamplona Navarra Spain
- IdiSNA; Navarra Institute for Health Research; Pamplona Spain
| | - A. Barber
- Department of Nutrition, Food Science and Physiology; University of Navarra; Pamplona Navarra Spain
| | - J. Prieto
- Department of Gene Therapy and Hepatology; CIMA; University of Navarra; Pamplona Navarra Spain
- CIBERehd; Institute of Health Carlos III; Madrid Spain
| | - J. A. Martínez
- Department of Nutrition, Food Science and Physiology; University of Navarra; Pamplona Navarra Spain
- Centre for Nutrition Research; University of Navarra; Pamplona Navarra Spain
- IdiSNA; Navarra Institute for Health Research; Pamplona Spain
- CIBERobn; Physiopathology of Obesity and Nutrition; Institute of Health Carlos III; Madrid Spain
| | - M. Bustos
- Department of Gene Therapy and Hepatology; CIMA; University of Navarra; Pamplona Navarra Spain
| | - M. J. Moreno-Aliaga
- Department of Nutrition, Food Science and Physiology; University of Navarra; Pamplona Navarra Spain
- Centre for Nutrition Research; University of Navarra; Pamplona Navarra Spain
- IdiSNA; Navarra Institute for Health Research; Pamplona Spain
- CIBERobn; Physiopathology of Obesity and Nutrition; Institute of Health Carlos III; Madrid Spain
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Oat β-glucan depresses SGLT1- and GLUT2-mediated glucose transport in intestinal epithelial cells (IEC-6). Nutr Res 2016; 36:541-52. [DOI: 10.1016/j.nutres.2016.02.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/10/2016] [Accepted: 02/16/2016] [Indexed: 01/28/2023]
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Chen L, Tuo B, Dong H. Regulation of Intestinal Glucose Absorption by Ion Channels and Transporters. Nutrients 2016; 8:nu8010043. [PMID: 26784222 PMCID: PMC4728656 DOI: 10.3390/nu8010043] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/18/2015] [Accepted: 01/06/2016] [Indexed: 12/14/2022] Open
Abstract
The absorption of glucose is electrogenic in the small intestinal epithelium. The major route for the transport of dietary glucose from intestinal lumen into enterocytes is the Na+/glucose cotransporter (SGLT1), although glucose transporter type 2 (GLUT2) may also play a role. The membrane potential of small intestinal epithelial cells (IEC) is important to regulate the activity of SGLT1. The maintenance of membrane potential mainly depends on the activities of cation channels and transporters. While the importance of SGLT1 in glucose absorption has been systemically studied in detail, little is currently known about the regulation of SGLT1 activity by cation channels and transporters. A growing line of evidence suggests that cytosolic calcium ([Ca2+]cyt) can regulate the absorption of glucose by adjusting GLUT2 and SGLT1. Moreover, the absorption of glucose and homeostasis of Ca2+ in IEC are regulated by cation channels and transporters, such as Ca2+ channels, K+ channels, Na+/Ca2+ exchangers, and Na+/H+ exchangers. In this review, we consider the involvement of these cation channels and transporters in the regulation of glucose uptake in the small intestine. Modulation of them may be a potential strategy for the management of obesity and diabetes.
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Affiliation(s)
- Lihong Chen
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi 563003, China.
| | - Biguang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi 563003, China.
| | - Hui Dong
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical College, and Digestive Disease Institute of Guizhou Province, Zunyi 563003, China.
- Department of Gastroenterology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
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Arakawa H, Ohmachi T, Ichiba K, Kamioka H, Tomono T, Kanagawa M, Idota Y, Hatano Y, Yano K, Morimoto K, Ogihara T. Interaction of Peptide Transporter 1 With d-Glucose and l-Glutamic Acid; Possible Involvement of Taste Receptors. J Pharm Sci 2016; 105:339-42. [DOI: 10.1016/j.xphs.2015.11.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/22/2015] [Accepted: 11/09/2015] [Indexed: 11/30/2022]
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Reyes-Fernandez PC, Fleet JC. Luminal glucose does not enhance active intestinal calcium absorption in mice: evidence against a role for Ca(v)1.3 as a mediator of calcium uptake during absorption. Nutr Res 2015; 35:1009-15. [PMID: 26403486 DOI: 10.1016/j.nutres.2015.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/25/2015] [Accepted: 08/27/2015] [Indexed: 12/12/2022]
Abstract
Intestinal Ca absorption occurs through a 1,25-dihydroxyvitamin D3 (1,25(OH)2D3)-regulated transcellular pathway, especially when habitual dietary Ca intake is low. Recently the L-type voltage-gated Ca channel, Cav1.3, was proposed to mediate active, transcellular Ca absorption in response to membrane depolarization caused by elevated luminal glucose levels after a meal. We tested the hypothesis that high luminal glucose could reveal a role for Cav1.3 in active intestinal Ca absorption in mice. Nine-week-old male C57BL/6 J mice were fed AIN93G diets containing either low (0.125%) or high (1%) Ca for 1 week, and Ca absorption was examined by an oral gavage method using a 45Ca-transport buffer containing 25 mmol/L of glucose or fructose. Transient receptor potential vanilloid 6 (TRPV6), calbindin D9k (CaBPD9k), and Cav1.3 messenger RNA (mRNA) levels were measured in the duodenum, jejunum, and ileum. TRPV6 and CaBPD9k expressions were highest in the duodenum, where active, 1,25(OH)2D3-regulated Ca absorption occurs, whereas Cav1.3 mRNA levels were similar across the intestinal segments. As expected, the low-Ca diet increased renal cytochrome p450-27B1 (CYP27B1) mRNA (P = .003), serum 1,25(OH)2D3 (P < .001), and Ca absorption efficiency by 2-fold with the fructose buffer. However, the glucose buffer used to favor Cav1.3 activation did not increase Ca absorption efficiency (P = .6) regardless of the dietary Ca intake level. Collectively, our results show that glucose did not enhance Ca absorption and they do not support a critical role for Cav1.3 in either basal or vitamin D-regulated intestinal Ca absorption in vivo.
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Affiliation(s)
| | - James C Fleet
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907-2059, USA.
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29
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Mace OJ, Tehan B, Marshall F. Pharmacology and physiology of gastrointestinal enteroendocrine cells. Pharmacol Res Perspect 2015. [PMID: 26213627 PMCID: PMC4506687 DOI: 10.1002/prp2.155] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Gastrointestinal (GI) polypeptides are secreted from enteroendocrine cells (EECs). Recent technical advances and the identification of endogenous and synthetic ligands have enabled exploration of the pharmacology and physiology of EECs. Enteroendocrine signaling pathways stimulating hormone secretion involve multiple nutrient transporters and G protein-coupled receptors (GPCRs), which are activated simultaneously under prevailing nutrient conditions in the intestine following a meal. The majority of studies investigate hormone secretion from EECs in response to single ligands and although the mechanisms behind how individual signaling pathways generate a hormonal output have been well characterized, our understanding of how these signaling pathways converge to generate a single hormone secretory response is still in its infancy. However, a picture is beginning to emerge of how nutrients and full, partial, or allosteric GPCR ligands differentially regulate the enteroendocrine system and its interaction with the enteric and central nervous system. So far, activation of multiple pathways underlies drug discovery efforts to harness the therapeutic potential of the enteroendocrine system to mimic the phenotypic changes observed in patients who have undergone Roux-en-Y gastric surgery. Typically obese patients exhibit ∼30% weight loss and greater than 80% of obese diabetics show remission of diabetes. Targeting combinations of enteroendocrine signaling pathways that work synergistically may manifest with significant, differentiated EEC secretory efficacy. Furthermore, allosteric modulators with their increased selectivity, self-limiting activity, and structural novelty may translate into more promising enteroendocrine drugs. Together with the potential to bias enteroendocrine GPCR signaling and/or to activate multiple divergent signaling pathways highlights the considerable range of therapeutic possibilities available. Here, we review the pharmacology and physiology of the EEC system.
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Affiliation(s)
- O J Mace
- Heptares Therapeutics Ltd BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
| | - B Tehan
- Heptares Therapeutics Ltd BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
| | - F Marshall
- Heptares Therapeutics Ltd BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
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Abstract
For humans and rodents, duodenum is a very important site of calcium absorption since it is exposed to ionized calcium released from dietary complexes by gastric acid. Calcium traverses the duodenal epithelium via both transcellular and paracellular pathways in a vitamin D-dependent manner. After binding to the nuclear vitamin D receptor, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] upregulates the expression of several calcium transporter genes, e.g., TRPV5/6, calbindin-D9k, plasma membrane Ca(2+)-ATPase1b, and NCX1, thereby enhancing the transcellular calcium transport. This action has been reported to be under the regulation of parathyroid-kidney-intestinal and bone-kidney-intestinal axes, in which the plasma calcium and fibroblast growth factor-23 act as negative feedback regulators, respectively. 1,25(OH)2D3 also modulates the expression of tight junction-related genes and convective water flow, presumably to increase the paracellular calcium permeability and solvent drag-induced calcium transport. However, vitamin D-independent calcium absorption does exist and plays an important role in calcium homeostasis under certain conditions, particularly in neonatal period, pregnancy, and lactation as well as in naturally vitamin D-impoverished subterranean mammals.
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Abstract
It has been proposed that the non-saturable component of intestinal glucose absorption, apparent following prolonged exposure to high intraluminal glucose concentrations, is mediated via the low affinity glucose and fructose transporter, GLUT2, upregulated within the small intestinal apical border. The evidence that the non-saturable transport component is mediated via an apical membrane sugar transporter is that it is inhibited by phloretin, after exposure to phloridzin. Since the other apical membrane sugar transporter, GLUT5, is insensitive to inhibition by either cytochalasin B, or phloretin, GLUT2 was deduced to be the low affinity sugar transport route. As in its uninhibited state, polarized intestinal glucose absorption depends both on coupled entry of glucose and sodium across the brush border membrane and on the enterocyte cytosolic glucose concentration exceeding that in both luminal and submucosal interstitial fluids, upregulation of GLUT2 within the intestinal brush border will usually stimulate downhill glucose reflux to the intestinal lumen from the enterocytes; thereby reducing, rather than enhancing net glucose absorption across the luminal surface. These states are simulated with a computer model generating solutions to the differential equations for glucose, Na and water flows between luminal, cell, interstitial and capillary compartments. The model demonstrates that uphill glucose transport via SGLT1 into enterocytes, when short-circuited by any passive glucose carrier in the apical membrane, such as GLUT2, will reduce transcellular glucose absorption and thereby lead to increased paracellular flow. The model also illustrates that apical GLUT2 may usefully act as an osmoregulator to prevent excessive enterocyte volume change with altered luminal glucose concentrations.
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Affiliation(s)
- Richard J Naftalin
- Department of Physiology and BHF Centre of Research Excellence, King's College London, School of Medicine, London, SE1 9HN, UK
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Röder PV, Geillinger KE, Zietek TS, Thorens B, Koepsell H, Daniel H. The role of SGLT1 and GLUT2 in intestinal glucose transport and sensing. PLoS One 2014; 9:e89977. [PMID: 24587162 PMCID: PMC3935955 DOI: 10.1371/journal.pone.0089977] [Citation(s) in RCA: 271] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022] Open
Abstract
Intestinal glucose absorption is mediated by SGLT1 whereas GLUT2 is considered to provide basolateral exit. Recently, it was proposed that GLUT2 can be recruited into the apical membrane after a high luminal glucose bolus allowing bulk absorption of glucose by facilitated diffusion. Moreover, SGLT1 and GLUT2 are suggested to play an important role in intestinal glucose sensing and incretin secretion. In mice that lack either SGLT1 or GLUT2 we re-assessed the role of these transporters in intestinal glucose uptake after radiotracer glucose gavage and performed Western blot analysis for transporter abundance in apical membrane fractions in a comparative approach. Moreover, we examined the contribution of these transporters to glucose-induced changes in plasma GIP, GLP-1 and insulin levels. In mice lacking SGLT1, tissue retention of tracer glucose was drastically reduced throughout the entire small intestine whereas GLUT2-deficient animals exhibited higher tracer contents in tissue samples than wild type animals. Deletion of SGLT1 resulted also in reduced blood glucose elevations and abolished GIP and GLP-1 secretion in response to glucose. In mice lacking GLUT2, glucose-induced insulin but not incretin secretion was impaired. Western blot analysis revealed unchanged protein levels of SGLT1 after glucose gavage. GLUT2 detected in apical membrane fractions mainly resulted from contamination with basolateral membranes but did not change in density after glucose administration. SGLT1 is unequivocally the prime intestinal glucose transporter even at high luminal glucose concentrations. Moreover, SGLT1 mediates glucose-induced incretin secretion. Our studies do not provide evidence for GLUT2 playing any role in either apical glucose influx or incretin secretion.
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Affiliation(s)
- Pia V. Röder
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
| | - Kerstin E. Geillinger
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
| | - Tamara S. Zietek
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
| | - Bernard Thorens
- Center for Integrative Genomics, Université de Lausanne, Lausanne, Switzerland
| | - Hermann Koepsell
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Julius-Maximilians-Universität Würzburg, Würzburg, Bavaria, Germany
| | - Hannelore Daniel
- ZIEL Research Center for Nutrition and Food Sciences, Biochemistry Unit, Technische Universität München, Freising, Bavaria, Germany
- * E-mail:
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33
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Regulation of glucose transporter expression in human intestinal Caco-2 cells following exposure to an anthocyanin-rich berry extract. PLoS One 2013; 8:e78932. [PMID: 24236070 PMCID: PMC3827299 DOI: 10.1371/journal.pone.0078932] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 09/25/2013] [Indexed: 02/06/2023] Open
Abstract
Polyphenols contained within plant tissues are consumed in significant amounts in the human diet and are known to influence a number of biological processes. This study investigated the effects of an anthocyanin-rich berry-extract on glucose uptake by human intestinal Caco-2 cells. Acute exposure (15 min) to berry extract (0.125%, w/v) significantly decreased both sodium-dependent (Total uptake) and sodium-independent (facilitated uptake) ³H-D-glucose uptake. In longer-term studies, SGLT1 mRNA and GLUT2 mRNA expression were reduced significantly. Polyphenols are known to interact directly with glucose transporters to regulate the rate of glucose absorption. Our in vitro data support this mechanism and also suggest that berry flavonoids may modulate post-prandial glycaemia by decreasing glucose transporter expression. Further studies are warranted to investigate the longer term effects of berry flavonoids on the management of glycaemia in human volunteers.
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34
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Mace OJ, Marshall F. DIGESTIVE PHYSIOLOGY OF THE PIG SYMPOSIUM: Gut chemosensing and the regulation of nutrient absorption and energy supply1. J Anim Sci 2013; 91:1932-45. [DOI: 10.2527/jas.2012-5906] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- O. J. Mace
- Heptares Therapeutics, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
| | - F. Marshall
- Heptares Therapeutics, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
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35
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Kopic S, Geibel JP. Gastric acid, calcium absorption, and their impact on bone health. Physiol Rev 2013; 93:189-268. [PMID: 23303909 DOI: 10.1152/physrev.00015.2012] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Calcium balance is essential for a multitude of physiological processes, ranging from cell signaling to maintenance of bone health. Adequate intestinal absorption of calcium is a major factor for maintaining systemic calcium homeostasis. Recent observations indicate that a reduction of gastric acidity may impair effective calcium uptake through the intestine. This article reviews the physiology of gastric acid secretion, intestinal calcium absorption, and their respective neuroendocrine regulation and explores the physiological basis of a potential link between these individual systems.
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Affiliation(s)
- Sascha Kopic
- Department of Surgery and Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
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36
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Pang G, Xie J, Chen Q, Hu Z. How functional foods play critical roles in human health. FOOD SCIENCE AND HUMAN WELLNESS 2012. [DOI: 10.1016/j.fshw.2012.10.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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37
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Woudenberg-Vrenken TE, Lameris AL, Weißgerber P, Olausson J, Flockerzi V, Bindels RJM, Freichel M, Hoenderop JGJ. Functional TRPV6 channels are crucial for transepithelial Ca2+ absorption. Am J Physiol Gastrointest Liver Physiol 2012; 303:G879-85. [PMID: 22878123 DOI: 10.1152/ajpgi.00089.2012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
TRPV6 is considered the primary protein responsible for transcellular Ca2+ absorption. In vitro studies demonstrate that a negatively charged amino acid (D) within the putative pore region of mouse TRPV6 (position 541) is critical for Ca2+ permeation of the channel. To elucidate the role of TRPV6 in transepithelial Ca2+ transport in vivo, we functionally analyzed a TRPV6D541A/D541A knockin mouse model. After weaning, mice were fed a regular (1% wt/wt) or Ca2+-deficient (0.02% wt/wt) diet and housed in metabolic cages. Blood was sampled for Ca2+ measurements, and the expression of Ca2+ transport proteins was analyzed in kidney and duodenum. Intestinal 45Ca2+ uptake was measured in vivo by an absorption assay. Challenging the mice with the Ca2+-deficient diet resulted in hypocalcemia in wild-type and TRPV6D541A/D541A mice. On a low-Ca2+ diet both mouse strains displayed increased expression of intestinal TRPV6, calbindin-D(9K), and renal TRPV5. TRPV6D541A/D541A mice showed significantly impaired intestinal Ca2+ uptake compared with wild-type mice, and duodenal TRPV5 expression was increased in TRPV6D541A/D541A mice. On a normal diet, serum Ca2+ concentrations normalized in both mouse strains. Under these conditions, intestinal Ca2+ uptake was similar, and the expression levels of renal and intestinal Ca2+ transport proteins were not affected. We demonstrate that TRPV6D541A/D541A mice exhibit impaired transcellular Ca2+ absorption. Duodenal TRPV5 expression was increased in TRPV6D541A/D541A mice, albeit insufficient to correct for the diminished Ca2+ absorption. Under normal conditions, when passive Ca2+ transport is predominant, no differences between wild-type and TRPV6D541A/D541A mice were observed. Our results demonstrate a specific role for TRPV6 in transepithelial Ca2+ absorption.
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Affiliation(s)
- Titia E Woudenberg-Vrenken
- Department of Physiology, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Duodenal calcium transporter mRNA expression in stressed male rats treated with diazepam, fluoxetine, reboxetine, or venlafaxine. Mol Cell Biochem 2012; 369:87-94. [DOI: 10.1007/s11010-012-1371-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 06/20/2012] [Indexed: 01/22/2023]
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39
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Zheng Y, Sarr MG. Translocation of transfected GLUT2 to the apical membrane in rat intestinal IEC-6 cells. Dig Dis Sci 2012; 57:1203-12. [PMID: 22116644 PMCID: PMC3331913 DOI: 10.1007/s10620-011-1984-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 11/10/2011] [Indexed: 02/01/2023]
Abstract
AIM In this study, we transfected the full length cDNA of glucose transporter 2 (GLUT2) into IEC-6 cells (which lack GLUT2 expression) to investigate GLUT2 translocation in enterocytes. The purpose of this study was to investigate cellular mechanisms of GLUT2 translocation and its signaling pathway. METHODS Rat GLUT2 cDNA was transfected into IEC-6 cells. Glucose uptake was measured by incubating cell monolayers with glucose (0.5-50 mM), containing (14)C-D-glucose and (3)H-L-glucose, to measure stereospecific, carrier-mediated and passive uptake. We imaged GLUT2 immunoreactivity by confocal fluorescence microscopy. We evaluated the GLUT2 inhibitor (1 mM phloretin), SGLT1 inhibitor (0.5 mM phlorizin), disrupting microtubular integrity (2 μM nocodazole and 0.5 μM cytochalasin B), protein kinase C (PKC) inhibitors (50 nM calphostin C and 10 μM chelerythrine), and PKC activator (50 nM phorbol 12-myristate 13-acetate: PMA). RESULTS In GLUT2-IEC cells, the K(m) (54.5 mM) increased compared with non-transfected IEC-6 cells (7.8 mM); phloretin (GLUT2 inhibitor) inhibited glucose uptake to that of non-transfected IEC-6 cells (P < 0.05). Nocodazole and cytochalasin B (microtubule disrupters) inhibited uptake by 43-58% only at glucose concentrations ≥25 and 50 mM and the 10-min incubations. Calphostin C (PKC inhibitor) reproduced the inhibition of nocodazole; PMA (a PKC activator) enhanced glucose uptake by 69%. Exposure to glucose increased the GFP signal at the apical membrane of GLUT-1EC cells. CONCLUSION IEC-6 cells lacking GLUT2 translocate GLUT2 apically when transfected to express GLUT2. Translocation of GLUT2 occurs through glucose stimulation via a PKC-dependent signaling pathway and requires integrity of the microtubular skeletal structure.
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Affiliation(s)
- Ye Zheng
- Department of Surgery and The Gastroenterology Research Unit, Mayo Clinic (GU 10-01), 200 1st Street SW, Rochester, MN 55905, USA.
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Mace OJ, Schindler M, Patel S. The regulation of K- and L-cell activity by GLUT2 and the calcium-sensing receptor CasR in rat small intestine. J Physiol 2012; 590:2917-36. [PMID: 22495587 DOI: 10.1113/jphysiol.2011.223800] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Intestinal enteroendocrine cells (IECs) secrete gut peptides in response to both nutrients and non-nutrients. Glucose and amino acids both stimulate gut peptide secretion. Our hypothesis was that the facilitative glucose transporter, GLUT2, could act as a glucose sensor and the calcium-sensing receptor, CasR, could detect amino acids in the intestine to modify gut peptide secretion. We used isolated loops of rat small intestine to study the secretion of gluco-insulinotropic peptide (GIP), glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) secretion stimulated by luminal perfusion of nutrients or bile acid. Inhibition of the sodium-dependent glucose cotransporter 1 (SGLT1) with phloridzin partially inhibited GIP, GLP-1 and PYY secretion by 45%, suggesting another glucose sensor might be involved in modulating peptide secretion. The response was completely abolished in the presence of the GLUT2 inhibitors phloretin or cytochalasin B. Given that GLUT2 modified gut peptide secretion stimulated by glucose, we investigated whether it was involved in the secretion of gut peptide by other gut peptide secretagogues. Phloretin completely abolished gut peptide secretion stimulated by artificial sweetener (sucralose), dipeptide (glycylsarcosine), lipid (oleoylethanolamine), short chain fatty acid (propionate) and major rat bile acid (taurocholate) indicating a fundamental position for GLUT2 in the gut peptide secretory mechanism. We investigated how GLUT2 was able to influence gut peptide secretion mediated by a diverse range of stimulators and discovered that GLUT2 affected membrane depolarisation through the closure of K+(ATP)-sensitive channels. In the absence of SGLT1 activity (or presence of phloridzin), the secretion of GIP, GLP-1 and PYY was sensitive to K+(ATP)-sensitive channel modulators tolbutamide and diazoxide. L-amino acids phenylalanine (Phe), tryptophan (Trp), asparagine (Asn), arginine (Arg) and glutamine (Gln) also stimulated GIP, GLP-1 and PYY secretion, which was completely abolished when extracellular Ca2+ was absent. The gut peptide response stimulated by the amino acids was also blocked by the CasR inhibitor Calhex 231 and augmented by the CasR agonist NPS-R568. GLUT2 and CasR regulate K- and L-cell activity in response to nutrient and non-nutrient stimuli.
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41
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Chaudhry RM, Scow JS, Madhavan S, Duenes JA, Sarr MG. Acute enterocyte adaptation to luminal glucose: a posttranslational mechanism for rapid apical recruitment of the transporter GLUT2. J Gastrointest Surg 2012; 16:312-9; discussion 319. [PMID: 22068967 PMCID: PMC3265642 DOI: 10.1007/s11605-011-1752-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 10/13/2011] [Indexed: 01/31/2023]
Abstract
BACKGROUND Glucose absorption postprandially increases markedly to levels far greater than possible by the classic glucose transporter sodium-glucose cotransporter 1 (SGLT1). HYPOTHESIS Luminal concentrations of glucose >50 mM lead to rapid, phenotypic, non-genomic adaptations by the enterocyte to recruit another transporter, glucose transporter 2 (GLUT2), to the apical membrane to increase glucose absorption. METHODS Isolated segments of jejunum were perfused in vivo with glucose-containing solutions in anesthetized rats. Carrier-mediated glucose uptake was measured in 10 and 100 mM glucose solutions (n = 6 rats each) with and without selective inhibitors of SGLT1 and GLUT2. RESULTS The mean rate of carrier-mediated glucose uptake increased in rats perfused with 100 mM versus 10 mM glucose to 13.9 ± 2.9 μmol from 2.1 ± 0.1 μmol, respectively (p < 0.0001). Using selective inhibitors, the relative contribution of GLUT2 to glucose absorption was 56% in the 100 mM concentration of glucose compared to the 10 mM concentration (27%; p < 0.01). Passive absorption accounted for 6% of total glucose absorption at 100 mM glucose. CONCLUSION A small amount of GLUT2 is active at the lesser luminal concentrations of glucose, but when exposed to concentrations of 100 mM, the enterocyte presumably changes its phenotype by recruiting GLUT2 apically to markedly augment glucose absorption.
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Affiliation(s)
- Rizwan M Chaudhry
- Department of Surgery and Gastroenterology Research Unit, Mayo Clinic (GU 10-01), 200 1st Street SW, Rochester, MN 55905, USA
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Nerveless and gutsy: intestinal nutrient sensing from invertebrates to humans. Semin Cell Dev Biol 2012; 23:614-20. [PMID: 22248674 PMCID: PMC3712190 DOI: 10.1016/j.semcdb.2012.01.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 12/27/2011] [Accepted: 01/04/2012] [Indexed: 12/22/2022]
Abstract
The increasingly recognized role of gastrointestinal signals in the regulation of food intake, insulin production and peripheral nutrient storage has prompted a surge of interest in studying how the gastrointestinal tract senses and responds to nutritional information. Identification of metabolically important intestinal nutrient sensors could provide potential new drug targets for the treatment of diabetes, obesity and gastrointestinal disorders. From a more fundamental perspective, the study of intestinal chemosensation is revealing novel, non-neuronal modes of communication involving differentiated epithelial cells. It is also identifying signalling mechanisms downstream of not only canonical receptors but also nutrient transporters, thereby supporting a chemosensory role for “transceptors” in the intestine. This review describes known and proposed mechanisms of intestinal carbohydrate, protein and lipid sensing, best characterized in mammalian systems. It also highlights the potential of invertebrate model systems such as C. elegans and Drosophila melanogaster by summarizing known examples of molecular evolutionary conservation. Recently developed genetic tools in Drosophila, an emerging model system for the study of physiology and metabolism, allow the temporal, spatial and high-throughput manipulation of putative intestinal sensors. Hence, fruit flies may prove particularly suited to the study of the link between intestinal nutrient sensing and metabolic homeostasis.
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Abstract
Ingestion of a meal triggers a range of physiological responses both within and outside the gut, and results in the remote modulation of appetite and glucose homeostasis. Luminal contents are sensed by specialised chemosensitive cells scattered throughout the intestinal epithelium. These enteroendocrine and tuft cells make direct contact with the gut lumen and release a range of chemical mediators, which can either act in a paracrine fashion interacting with neighbouring cells and nerve endings or as classical circulating hormones. At the molecular level, the chemosensory machinery involves multiple and complex signalling pathways including activation of G-protein-coupled receptors and solute carrier transporters. This chapter will discuss our current knowledge of the molecular mechanisms underlying intestinal chemosensation with a particular focus on the relatively well-characterised nutrient-triggered secretion from the enteroendocrine system.
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Affiliation(s)
- Gwen Tolhurst
- Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0XY, UK
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Goto T, Horita M, Nagai H, Nagatomo A, Nishida N, Matsuura Y, Nagaoka S. Tiliroside, a glycosidic flavonoid, inhibits carbohydrate digestion and glucose absorption in the gastrointestinal tract. Mol Nutr Food Res 2011; 56:435-45. [DOI: 10.1002/mnfr.201100458] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 08/09/2011] [Accepted: 08/18/2011] [Indexed: 12/11/2022]
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Larqué C, Velasco M, Navarro-Tableros V, Duhne M, Aguirre J, Gutiérrez-Reyes G, Moreno J, Robles-Diaz G, Hong E, Hiriart M. Early endocrine and molecular changes in metabolic syndrome models. IUBMB Life 2011; 63:831-9. [PMID: 21905198 DOI: 10.1002/iub.544] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 07/02/2011] [Indexed: 12/12/2022]
Abstract
The twenty-first century arrived in the middle of a global epidemic of metabolic syndrome (MS) and type 2 diabetes mellitus (DM2). It is generally accepted that an excess of nutrients linked to a low physical activity triggers the problem. However, the molecular features that interact to develop the MS are not clear. In an effort to understand and control them, they have been extensively studied, but this goal has not been achieved yet. Nonhuman animal models have been used to explore diet and genetic factors in which experimental conditions are controlled. For example, only one factor in the diet, such as fats or carbohydrates can be modified to better understand a single change that would be impossible in humans. Most of the studies have been done in rodents. However, it is difficult to directly compare them, because experiments are different in more than one variable; genetic strains, amount, and the type of fat used in the diet and sex. Thus, the only possible criteria of comparison are the relevance of the observed changes. We review different animal models and add some original observations on short-term changes in metabolism and beta cells in our own model of adult Wistar rats that are not especially prone to get fat or develop DM2, treated with 20% sucrose in drinking water. One early change observed in pancreatic beta cells is the increase in GLUT2 expression that is located to the membrane of the cells. This change could partially explain the presence of insulin hypersecretion and hyperinsulinemia in these rats. Understanding early changes that lead to MS and in time to pancreatic islet exhaustion is an important biomedical problem that may contribute to learn how to prevent or even reverse MS, before developing DM2.
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Affiliation(s)
- Carlos Larqué
- Neuroscience Division, Department of Neural Development and Physiology, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico DF, Mexico
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Perego S, Cosentino S, Fiorilli A, Tettamanti G, Ferraretto A. Casein phosphopeptides modulate proliferation and apoptosis in HT-29 cell line through their interaction with voltage-operated L-type calcium channels. J Nutr Biochem 2011; 23:808-16. [PMID: 21840696 DOI: 10.1016/j.jnutbio.2011.04.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 03/23/2011] [Accepted: 04/04/2011] [Indexed: 02/03/2023]
Abstract
At the intestinal level, proliferation and apoptosis are modulated by the extracellular calcium concentration; thus, dietary calcium may exert a chemoprotective role on normal differentiated intestinal cells, while it may behave as a carcinogenesis promoter in transformed cells. Calcium in milk is associated with casein and casein phosphopeptides (CPPs), hence is preserved from precipitation. CPPs were demonstrated to induce uptake of extracellular calcium ions by in vitro intestinal tumor HT-29 cells but only upon differentiation. Here, the hypothesis that CPPs could differently affect proliferation and apoptosis in undifferentiated and differentiated HT-29 cells through their binding with calcium ions was investigated. Results showed that CPPs protect differentiated intestinal cells from calcium overload toxicity and prevent their apoptosis favoring proliferation while inducing apoptosis in undifferentiated tumor cells. The CPP effect on undifferentiated HT-29 cells, similar to that exerted by ethyleneglycol-O, O'-bis(2-aminoethyl)-N, N, N', N'-tetraacetic acid (EGTA), is presumably due to the ability in binding the extracellular calcium. The effect on differentiated HT-29 cells is coupled to the interaction of CPPs with the voltage-operated L-type calcium channels, known to activate calcium entry into the cells under depolarization and to exert a mitogenic effect: the use of an agonist potentiates the cell response to CPPs, while the antagonists abolish the response to CPPs (36% of examined cells) or reduce both the percentage of responsive cells and the increase of intracellular calcium concentration. Taken together, these results confirm the potentialities of CPPs as nutraceuticals/functional food and also as modulators of cellular processes connected to the expression of a cancer phenotype.
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Affiliation(s)
- Silvia Perego
- Dipartimento di Chimica, Biochimica e Biotecnologie per la Medicina, Università degli Studi di Milano, Milano, Italy
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47
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Kellett GL. Alternative perspective on intestinal calcium absorption: proposed complementary actions of Ca(v)1.3 and TRPV6. Nutr Rev 2011; 69:347-70. [PMID: 21729089 DOI: 10.1111/j.1753-4887.2011.00395.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcellular models of dietary Ca(2+) absorption by the intestine assign essential roles to TRPV6 and calbindin-D(9K) . However, studies with gene-knockout mice challenge this view. Something fundamental is missing. The L-type channel Ca(v) 1.3 is located in the apical membrane from the duodenum to the ileum. In perfused rat jejunum in vivo and in Caco-2 cells, Ca(v) 1.3 mediates sodium glucose transporter 1 (SGLT1)-dependent and prolactin-induced active, transcellular Ca(2+) absorption, respectively. TRPV6 is activated by hyperpolarization and is vitamin D dependent; in contrast, Ca(v) 1.3 is activated by depolarization and is independent of calbindin-D(9K) and vitamin D. This review considers evidence supporting the idea that Ca(v) 1.3 and TRPV6 have complementary roles in the regulation of intestinal Ca(2+) absorption as depolarization and repolarization of the apical membrane occur during and between digestive periods, respectively, and as chyme moves from one intestinal segment to another and food transit times increase. Reassessment of current arguments for paracellular flow reveals that key phenomena have alternative explanations within the integrated Ca(v) 1.3/TRPV6 view of transcellular Ca(2+) absorption.
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Affiliation(s)
- George L Kellett
- Department of Biology, University of York, Heslington, United Kingdom.
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48
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Fleet JC, Schoch RD. Molecular mechanisms for regulation of intestinal calcium absorption by vitamin D and other factors. Crit Rev Clin Lab Sci 2011; 47:181-95. [PMID: 21182397 DOI: 10.3109/10408363.2010.536429] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Optimal intestinal calcium (Ca) absorption is necessary for the protection of bone and the prevention of osteoporosis. Ca absorption can be represented as the sum of a saturable pathway and a non-saturable pathway that is primarily dependent upon luminal Ca concentration. While models have been proposed to describe these transport components, significant gaps still exist in our understanding of these processes. Habitual low intake of Ca up-regulates the saturable transport pathway, a process mediated by increased renal production of 1,25 dihydroxyvitamin D (1,25(OH)(2)D). Consistent with this, low vitamin D status as well as deletion/mutation of the vitamin D receptor (VDR) or 25 hydroxyvitamin D-1α hydroxylase (CYP27B1) genes limit Ca absorption by reducing the saturable pathway. There is some evidence that non-saturable Ca absorption in the ileum is also regulated by vitamin D status, but the mechanism is unclear. Treatment with a number of hormones can regulate Ca absorption in vivo (e.g. parathyroid hormone (PTH), thyroid hormone, growth hormone (GH)/insulin-like growth factor I (IGF-1), estrogen, testosterone). However, some of these actions are indirect (i.e. mediated through the regulation of vitamin D metabolism or signaling), whereas only a few (e.g. estrogen, IGF-1) have been shown to persist in the absence of vitamin D signaling.
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Affiliation(s)
- James C Fleet
- Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana, USA
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49
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Manzano S, Williamson G. Polyphenols and phenolic acids from strawberry and apple decrease glucose uptake and transport by human intestinal Caco-2 cells. Mol Nutr Food Res 2010; 54:1773-80. [DOI: 10.1002/mnfr.201000019] [Citation(s) in RCA: 194] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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50
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Saksena S, Tyagi S, Goyal S, Gill RK, Alrefai WA, Ramaswamy K, Dudeja PK. Stimulation of apical Cl⁻/HCO₃⁻(OH⁻) exchanger, SLC26A3 by neuropeptide Y is lipid raft dependent. Am J Physiol Gastrointest Liver Physiol 2010; 299:G1334-43. [PMID: 20884887 PMCID: PMC3006247 DOI: 10.1152/ajpgi.00039.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neuropeptide Y (NPY), an important proabsorptive hormone of the gastrointestinal tract has been shown to inhibit chloride secretion and stimulate NaCl absorption. However, mechanisms underlying the proabsorptive effects of NPY are not fully understood. The present studies were designed to examine the direct effects of NPY on apical Cl⁻/HCO₃⁻(OH⁻) exchange activity and the underlying mechanisms involved utilizing Caco2 cells. Our results showed that NPY (100 nM, 30 min) significantly increased Cl⁻/HCO₃⁻(OH⁻) exchange activity (∼2-fold). Selective NPY/Y1 or Y2 receptor agonists mimicked the effects of NPY. NPY-mediated stimulation of Cl⁻/HCO₃⁻(OH⁻) exchange activity involved the ERK1/2 MAP kinase-dependent pathway. Cell surface biotinylation studies showed that NPY does not alter DRA (apical Cl⁻/HCO₃⁻(OH⁻) exchanger) surface expression, ruling out the involvement of membrane trafficking events. Interestingly, DRA was found to be predominantly expressed in the detergent-insoluble (DI) and low-density fractions (LDF) of human colonic apical membrane vesicles (AMVs) representing lipid rafts. Depletion of membrane cholesterol by methyl-β-cyclodextrin (MβCD, 10 mM, 1 h) remarkably decreased DRA expression in the DI fractions. Similar results were obtained in Triton-X 100-treated Caco2 plasma membranes. DRA association with lipid rafts in the DI and LDF fractions of Caco2 cells was significantly enhanced (∼45%) by NPY compared with control. MβCD significantly decreased Cl⁻/HCO₃⁻(OH⁻) exchange activity in Caco2 cells as measured by DIDS- or niflumic acid-sensitive ³⁶Cl⁻ uptake (∼50%). Our results demonstrate that NPY modulates Cl⁻/HCO₃⁻(OH⁻) exchange activity by enhancing the association of DRA with lipid rafts, thereby resulting in an increase in Cl⁻/HCO₃⁻(OH⁻) exchange activity. Our findings suggest that the alteration in the association of DRA with lipid rafts may contribute to the proabsorptive effects of NPY in the human intestine.
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Affiliation(s)
- Seema Saksena
- Dept. of Medicine, University of Illinois at Chicago and Jesse Brown Veterans Affairs Medical Center, Illinois 60612, USA.
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