1
|
Li Y, Chaurasia B, Rahman MM, Kaddai V, Maschek JA, Berg JA, Wilkerson JL, Mahmassani ZS, Cox J, Wei P, Meikle PJ, Atkinson D, Wang L, Poss AM, Playdon MC, Tippetts TS, Mousa EM, Nittayaboon K, Anandh Babu PV, Drummond MJ, Clevers H, Shayman JA, Hirabayashi Y, Holland WL, Rutter J, Edgar BA, Summers SA. Ceramides Increase Fatty Acid Utilization in Intestinal Progenitors to Enhance Stemness and Increase Tumor Risk. Gastroenterology 2023; 165:1136-1150. [PMID: 37541526 PMCID: PMC10592225 DOI: 10.1053/j.gastro.2023.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 08/06/2023]
Abstract
BACKGROUND & AIMS Cancers of the alimentary tract, including esophageal adenocarcinomas, colorectal cancers, and cancers of the gastric cardia, are common comorbidities of obesity. Prolonged, excessive delivery of macronutrients to the cells lining the gut can increase one's risk for these cancers by inducing imbalances in the rate of intestinal stem cell proliferation vs differentiation, which can produce polyps and other aberrant growths. We investigated whether ceramides, which are sphingolipids that serve as a signal of nutritional excess, alter stem cell behaviors to influence cancer risk. METHODS We profiled sphingolipids and sphingolipid-synthesizing enzymes in human adenomas and tumors. Thereafter, we manipulated expression of sphingolipid-producing enzymes, including serine palmitoyltransferase (SPT), in intestinal progenitors of mice, cultured organoids, and Drosophila to discern whether sphingolipids altered stem cell proliferation and metabolism. RESULTS SPT, which diverts dietary fatty acids and amino acids into the biosynthetic pathway that produces ceramides and other sphingolipids, is a critical modulator of intestinal stem cell homeostasis. SPT and other enzymes in the sphingolipid biosynthesis pathway are up-regulated in human intestinal adenomas. They produce ceramides, which serve as prostemness signals that stimulate peroxisome-proliferator activated receptor-α and induce fatty acid binding protein-1. These actions lead to increased lipid utilization and enhanced proliferation of intestinal progenitors. CONCLUSIONS Ceramides serve as critical links between dietary macronutrients, epithelial regeneration, and cancer risk.
Collapse
Affiliation(s)
- Ying Li
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Bhagirath Chaurasia
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah; Division of Endocrinology, Department of Internal Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa.
| | - M Mahidur Rahman
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, Utah
| | - Vincent Kaddai
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - J Alan Maschek
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Jordan A Berg
- Department of Biochemistry, University of Utah, Salt Lake City, Utah
| | - Joseph L Wilkerson
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Ziad S Mahmassani
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah
| | - James Cox
- Department of Biochemistry, University of Utah, Salt Lake City, Utah
| | - Peng Wei
- Department of Biochemistry, University of Utah, Salt Lake City, Utah
| | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Donald Atkinson
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Liping Wang
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Annelise M Poss
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Mary C Playdon
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Trevor S Tippetts
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Esraa M Mousa
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah; Faculty of Science, Tanta University, Tanta, Egypt
| | - Kesara Nittayaboon
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah; Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand
| | - Pon Velayutham Anandh Babu
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Micah J Drummond
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah
| | - Hans Clevers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, The Netherlands; Oncode Institute, Utrecht, The Netherlands; Princess Maxima Center (PMC) for Pediatric Oncology, Utrecht, The Netherlands
| | - James A Shayman
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Yoshio Hirabayashi
- Cellular Informatics Laboratory, RIKEN Cluster for Pioneering Research, RIKEN, Wako-shi, Saitama Japan
| | - William L Holland
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah
| | - Jared Rutter
- Department of Biochemistry, University of Utah, Salt Lake City, Utah; Howard Hughes Medical Institute, Salt Lake City, Utah
| | - Bruce A Edgar
- Huntsman Cancer Institute and Department of Oncological Sciences, University of Utah, Salt Lake City, Utah
| | - Scott A Summers
- Department of Nutrition and Integrative Physiology and the Diabetes and Metabolism Research Center, University of Utah, Salt Lake City, Utah.
| |
Collapse
|
2
|
Poquet L, Wooster TJ. Infant digestion physiology and the relevance of in vitro biochemical models to test infant formula lipid digestion. Mol Nutr Food Res 2017; 60:1876-95. [PMID: 27279140 DOI: 10.1002/mnfr.201500883] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 03/05/2016] [Accepted: 05/31/2016] [Indexed: 01/30/2023]
Abstract
Lipids play an important role in the diet of preterm and term infants providing a key energy source and essential lipid components for development. While a lot is known about adult lipid digestion, our understanding of infant digestion physiology is still incomplete, the greatest gap being on the biochemistry of the small intestine, particularly the activity and relative importance of the various lipases active in the intestine. The literature has been reviewed to identify the characteristics of lipid digestion of preterm and term infants, but also to better understand the physiology of the infant gastrointestinal tract compared to adults that impacts the absorption of lipids. The main differences are a higher gastric pH, submicellar bile salt concentration, a far more important role of gastric lipases as well as differences at the level of the intestinal barrier. Importantly, the consequences of improper in vitro replication of gastric digestions conditions (pH and lipase specificity) are demonstrated using examples from the most recent of studies. It is true that some animal models could be adapted to study infant lipid digestion physiology, however the ethical relevance of such models is questionable, hence the development of accurate in vitro models is a must. In vitro models that combine up to date knowledge of digestion biochemistry with intestinal cells in culture are the best choice to replicate digestion and absorption in infant population, this would allow the adaptation of infant formula for a better digestion and absorption of dietary lipids by preterm and term infants.
Collapse
Affiliation(s)
- Laure Poquet
- Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, Switzerland
| | - Tim J Wooster
- Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne 26, Switzerland
| |
Collapse
|
3
|
Rodriguez Sawicki L, Bottasso Arias NM, Scaglia N, Falomir Lockhart LJ, Franchini GR, Storch J, Córsico B. FABP1 knockdown in human enterocytes impairs proliferation and alters lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1587-1594. [PMID: 28919479 DOI: 10.1016/j.bbalip.2017.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 09/06/2017] [Accepted: 09/10/2017] [Indexed: 12/17/2022]
Abstract
Fatty Acid-Binding Proteins (FABPs) are abundant intracellular proteins that bind long chain fatty acids (FA) and have been related with inmunometabolic diseases. Intestinal epithelial cells express two isoforms of FABPs: liver FABP (LFABP or FABP1) and intestinal FABP (IFABP or FABP2). They are thought to be associated with intracellular dietary lipid transport and trafficking towards diverse cell fates. But still their specific functions are not well understood. To study FABP1's functions, we generated an FABP1 knockdown model in Caco-2 cell line by stable antisense cDNA transfection (FABP1as). In these cells FABP1 expression was reduced up to 87%. No compensatory increase in FABP2 was observed, strengthening the idea of differential functions of both isoforms. In differentiated FABP1as cells, apical administration of oleate showed a decrease in its initial uptake rate and in long term incorporation compared with control cells. FABP1 depletion also reduced basolateral oleate secretion. The secreted oleate distribution showed an increase in FA/triacylglyceride ratio compared to control cells, probably due to FABP1's role in chylomicron assembly. Interestingly, FABP1as cells exhibited a dramatic decrease in proliferation rate. A reduction in oleate uptake as well as a decrease in its incorporation into the phospholipid fraction was observed in proliferating cells. Overall, our studies indicate that FABP1 is essential for proper lipid metabolism in differentiated enterocytes, particularly concerning fatty acids uptake and its basolateral secretion. Moreover, we show that FABP1 is required for enterocyte proliferation, suggesting that it may contribute to intestinal homeostasis.
Collapse
Affiliation(s)
- Luciana Rodriguez Sawicki
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Natalia María Bottasso Arias
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Natalia Scaglia
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Lisandro Jorge Falomir Lockhart
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Gisela Raquel Franchini
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Judith Storch
- Department of Nutritional Sciences and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ, USA
| | - Betina Córsico
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina.
| |
Collapse
|
4
|
Dixon JB, Raghunathan S, Swartz MA. A tissue-engineered model of the intestinal lacteal for evaluating lipid transport by lymphatics. Biotechnol Bioeng 2009; 103:1224-35. [PMID: 19396808 DOI: 10.1002/bit.22337] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Lacteals are the entry point of all dietary lipids into the circulation, yet little is known about the active regulation of lipid uptake by these lymphatic vessels, and there lacks in vitro models to study the lacteal-enterocyte interface. We describe an in vitro model of the human intestinal microenvironment containing differentiated Caco-2 cells and lymphatic endothelial cells (LECs). We characterize the model for fatty acid, lipoprotein, albumin, and dextran transport, and compare to qualitative uptake of fatty acids into lacteals in vivo. We demonstrate relevant morphological features of both cell types and strongly polarized transport of fatty acid in the intestinal-to-lymphatic direction. We found much higher transport rates of lipid than of dextran or albumin across the lymphatic endothelial monolayer, suggesting most lipid transport is active and intracellular. This was confirmed with confocal imaging of Bodipy, a fluorescent fatty acid, along with transmission electron microscopy. Since our model recapitulates crucial aspects of the in vivo lymphatic-enterocyte interface, it is useful for studying the biology of lipid transport by lymphatics and as a tool for screening drugs and nanoparticles that target intestinal lymphatics.
Collapse
Affiliation(s)
- J Brandon Dixon
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | | | | |
Collapse
|
5
|
Thumser AE, Storch J. Characterization of a BODIPY-labeled fluorescent fatty acid analogue. Binding to fatty acid-binding proteins, intracellular localization, and metabolism. Mol Cell Biochem 2007; 299:67-73. [PMID: 16645726 DOI: 10.1007/s11010-005-9041-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The BODIPY-labeled fatty acid analogues are a useful addition to the tools employed to study the cellular uptake and metabolism of lipids. In this study, we show that BODIPY FL C(16) binds to purified liver and intestinal fatty acid-binding proteins with high affinity at a site similar to that for the physiological fatty acid oleic acid. Further, in human intestinal Caco-2 cells BODIPY FL C(16) co-localizes extensively with mitochondria, endoplasmic reticulum/Golgi, and L-FABP. Virtually no esterification of BODIPY FL C(16) was observed under the experimental conditions employed. We conclude that BODIPY FL C(16) may be a useful tool for studying the distribution and function of FABPs in a cellular environment.
Collapse
Affiliation(s)
- Alfred E Thumser
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK.
| | | |
Collapse
|
6
|
Luci S, König B, Giemsa B, Huber S, Hause G, Kluge H, Stangl GI, Eder K. Feeding of a deep-fried fat causes PPARα activation in the liver of pigs as a non-proliferating species. Br J Nutr 2007; 97:872-82. [PMID: 17381980 DOI: 10.1017/s0007114507669256] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recent studies have shown that dietary oxidised fats influence the lipid metabolism in rats by activation of PPARα. In this study, we investigated whether a mildly oxidised fat causes activation of PPARα in pigs which are non-proliferators like man. Eighteen pigs were assigned to two groups and received either a diet containing 90 g/kg of a fresh fat or the same diet with 90 g/kg of an oxidised fat prepared by heating for 24 h at 180°C in a deep fryer. Pigs fed the oxidised fat had a higher peroxisome count, a higher activity of catalase and a higher mRNA concentration of mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase in the liver and a higher concentration of 3-hydroxybutyrate in plasma than pigs fed the fresh fat (P < 0·05). Hepatic mRNA concentrations of acyl-CoA oxidase and carnitine palmitoyltransferase-1 tended to be increased in pigs fed the oxidised fat compared to pigs fed the fresh fat (P < 0·10). Pigs fed the oxidised fat, moreover, had higher mRNA concentrations of sterol regulatory element-binding protein (SREBP)-1 and its target genes acetyl-CoA carboxylase and stearoyl-CoA desaturase in the liver and higher mRNA concentrations of SREBP-2 and its target genes 3-hydroxy-3-methylglutary-CoA reductase and LDL receptor in liver and small intestine. In conclusion, this study shows that even a mildly oxidised fat causes activation of PPARα in the liver of pigs. Up-regulation of SREBP and its target genes in liver and small intestine suggests that the oxidised fat could stimulate synthesis of cholesterol and TAG in these tissues.
Collapse
Affiliation(s)
- Sebastian Luci
- Institute of Agricultural and Nutritional Sciences, Martin-Luther- University of Halle- Wittenberg, Emil-Abderhalden-Strasse 26, D-06108 Halle (Saale), Germany
| | | | | | | | | | | | | | | |
Collapse
|
7
|
Helwig U, Rubin D, Kiosz J, Schreiber S, Fölsch UR, Nothnagel M, Döring F, Schrezenmeir J. The minor allele of the PPARγ2 Pro12Ala polymorphism is associated with lower postprandial TAG and insulin levels in non-obese healthy men. Br J Nutr 2007; 97:847-54. [PMID: 17408525 DOI: 10.1017/s0007114507665179] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The PPARγ Pro12Ala polymorphism has been associated in several studies with a decreased risk of obesity, type 2 diabetes and insulin resistance. Weak hints are available about the influence of PPARγ Pro12Ala on postprandial metabolism. In 708 men, aged 45 to 65 years the PPARγ2 Pro12Ala genotypes were determined and postprandial TAG, insulin, glucose and NEFA after a standardized mixed fat meal and insulin and glucose after a glucose load (oral glucose tolerance test; OGTT) were assessed. Using the total sample, we did not find a significant impact of the genotype on the postprandial metabolism. In the subgroup with BMI < 30 kg/m2, fasting and postprandial TAG and insulin levels as well as homeostasis model assessment of insulin resistance (HOMA) were significantly lower in the Ala12Ala group than in the Pro12Pro group after the mixed meal. In contrast, the groups did not differ in insulin levels and HOMA after the OGTT. To investigate if differences between a fat-containing meal and OGTT are caused by adiponectin, we examined a BMI- and age-matched subgroup. No differences were found between the genotypic groups. The effects of the PPARγ2 polymorphism on insulin sensitivity are mediated by affluent dietary fat. We did not find evidence that adiponectin as a fatty-acid-dependent adipocyte factor is a causative factor for this phenomenon.
Collapse
Affiliation(s)
- Ulf Helwig
- Federal Research Centre for Nutrition and Food, Location Kiel; Hermann-Weigmann Str.1, 24103 Kiel, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Klapper M, Böhme M, Nitz I, Döring F. Type 2 diabetes-associated fatty acid binding protein 2 promoter haplotypes are differentially regulated by GATA factors. Hum Mutat 2007; 29:142-9. [DOI: 10.1002/humu.20618] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
9
|
Hossain Z, Kurihara H, Hosokawa M, Takahashi K. Docosahexaenoic acid and eicosapentaenoic acid-enriched phosphatidylcholine liposomes enhance the permeability, transportation and uptake of phospholipids in Caco-2 cells. Mol Cell Biochem 2006; 285:155-63. [PMID: 16477371 DOI: 10.1007/s11010-005-9074-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Accepted: 11/04/2005] [Indexed: 11/29/2022]
Abstract
The influence of docosahexaenoic acid (DHA)- and eicosapentaenoic acid (EPA)-enriched phosphatidylcholine (PC) on the permeability, transport and uptake of phospholipids was evaluated in Caco-2 cells. The cells were grown on permeable polycarbonate transwell filters, thus allowing separate access to the apical and basolateral chambers. The monolayers of the cells were used to measure lucifer yellow permeability and transepithelial electrical resistance (TEER). Transcellular transportation of diphenylhexatriene (DPH) labeled-PC small unilamellar vesicles (SUV) from the apical to basolateral chamber, and uptake of the same SUV was monitored in the cell monolayers. Cell-membrane perturbation was evaluated to measure the release of lactate dehydrogenase and to determine the cell viability with sodium 2-(4-iodophenyl)-3-(4-nitrophenyl) -5-(2, 4-disulfophenyl)-2H-tetrazolium dye reduction assay. The lucifer yellow flux was 1.0 and 1.5 nmol/h/cm(2) with 50 microM PC, and 17.0 and 23.0 nmol/h/cm(2) with 100 microM PC when monolayers of Caco-2 cells were treated with DHA- and EPA-enriched PC, respectively. TEER decreased to 24 and 27% with 50 and 100 microM DHA-enriched PC, and to 25 and 30% with 50 and 100 microM EPA-enriched PC, respectively. Our results show that DHA- and EPA-enriched PC increases tight junction permeability across the Caco-2 cell monolayer whereas soy PC has no effect on tight junction permeability. Transportation and uptake of DHA- and EPA-enriched PC SUV differed significantly (P < 0.01) from those of soy PC SUV at all doses. We found that PC SUV transported across Caco-2 monolayer and was taken up by Caco-2 cells with very slight injury of the cell membrane up to 100 microM PC. Lactate dehydrogenase release and cell viability did not differ significantly between the treatment and control, emphasizing that injury was minimal. Our results suggest that DHA- and EPA-enriched PC enhance the permeability, transport and uptake of PC SUV across monolayers of Caco-2 cells.
Collapse
Affiliation(s)
- Zakir Hossain
- Division of Marine Biosciences, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, 041-8611, Japan.
| | | | | | | |
Collapse
|
10
|
|
11
|
Stierum R, Gaspari M, Dommels Y, Ouatas T, Pluk H, Jespersen S, Vogels J, Verhoeckx K, Groten J, van Ommen B. Proteome analysis reveals novel proteins associated with proliferation and differentiation of the colorectal cancer cell line Caco-2. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1650:73-91. [PMID: 12922171 DOI: 10.1016/s1570-9639(03)00204-8] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Here, we describe a proteomics approach to study protein expression changes in differentiating Caco-2 cells. Caco-2 is a colorectal carcinoma cell line, which upon differentiation loses its tumorigenic phenotype and displays characteristics of mature enterocytes, including brush borders with microvilli. Cells were grown in culture flasks and harvested at different stages of differentiation (days post-confluence: -3, 0, 3, 7, 10, 14, and 18). Two-dimensional gel electrophoresis was used to analyse proteome changes. Approximately 1400 protein spots were detected within the Caco-2 proteome, within the pH 4-7 range. Two-dimensional gel electrophoresis allowed for the detection of 18 proteins from which the levels of expression were found to be associated with differentiation. Of these proteins, 11 were identified by means of MALDI-TOF or NANO-ESI-MS/MS mass spectrometry and include liver fatty acid binding protein (FABL), three forms of alpha-enolase (ENOA), nucleoside diphosphate kinase A (NDKA), cofilin-1 (COF1), translationally controlled tumour protein (TCTP), mitochondrial 60-kDa heat shock protein (CH60), probable protein disulfide isomerase (ER60), creatine kinase B (KCRB), and glutathione S-transferase alpha (GTA1). Thus, proteomics revealed that the differentiation-related change in phenotype of Caco-2 involves changes in a variety of distinct biochemical pathways. Some of these proteins have not been shown before to be associated with Caco-2 differentiation (ER60; COF1; CH60; NDKA; TCTP and ENOA). Therefore, processes related to protein folding and disulfide bridge formation, cytoskeleton formation and maintenance, nucleotide metabolism, glycolysis as well as tumorigenesis-associated proteins may be involved in Caco-2 differentiation. Changes in the expression of CH60, TCTP, GTA1, NDKA, and FABL have also been reported to be associated with in vivo colon carcinogenesis. These findings illustrate that a combination of proteomics and cell culture is a useful approach to find markers for Caco-2 differentiation, which could contribute to the comprehension of the process of colon carcinogenesis.
Collapse
Affiliation(s)
- Rob Stierum
- TNO Nutrition and Food Research, Department of Biomolecular Sciences, P.O. Box 360, 3700 AJ, Zeist, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Ho SY, Delgado L, Storch J. Monoacylglycerol metabolism in human intestinal Caco-2 cells: evidence for metabolic compartmentation and hydrolysis. J Biol Chem 2002; 277:1816-23. [PMID: 11682480 DOI: 10.1074/jbc.m108027200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Free fatty acids (FFA) and sn-2-monoacylglycerol (MG), the two major hydrolysis products of dietary triacylglycerol (TG), are absorbed from the lumen into polarized enterocytes that line the small intestine. Intensive studies regarding FFA metabolism in the intestine have been published; however, little is known regarding the metabolism of MG. In these studies, we examined the metabolism of sn-2-monoolein (sn-2-18:1) by human intestinal Caco-2 cells. To mimic the physiological presentation of MG to the enterocyte, the metabolism of [(3)H]sn-2-monoolein was examined by adding taurocholate-mixed sn-2-18:1 and albumin-bound sn-2-18:1 at the apical (AP) and basolateral (BL) surfaces of the Caco-2 cell, respectively. The results demonstrate that more sn-2-18:1 was incorporated into TG from AP taurocholate-mixed sn-2-18:1, whereas more phospholipid was synthesized from BL albumin-bound sn-2-18:1. The TG:phospholipid ratio was approximately 5-fold higher for AP relative to BL MG incubation. Qualitatively similar results were observed for bovine serum albumin-bound MG added at the apical surface. It was also found that substantial sn-2-18:1 radioactivity was recovered in the FFA fraction, suggesting that sn-2-18:1 may be directly hydrolyzed within the Caco-2. We therefore used reverse transcription-PCR with primers designed from the murine MG lipase (MGL) gene, and detected the presence of MG lipase mRNA in Caco-2. The human MGL gene was cloned and found to be 83% identical to the murine MGL, and identical to a previously described lysophospholipase-like protein. Northern blot analysis showed the expression of MGL throughout Caco-2 differentiation. Thus, MG metabolism in Caco-2 cells may include not only well established anabolic processes, but also catabolic processes. Further, the observed polarity of MG metabolism suggests that, as for fatty acids, separate precursor and/or product pools of lipid may exist in the intestinal enterocyte.
Collapse
Affiliation(s)
- Shiu-Ying Ho
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey 08901-8525, USA
| | | | | |
Collapse
|
13
|
Gedde-Dahl A, Kulseth MA, Ranheim T, Drevon CA, Rustan AC. Reduced secretion of triacylglycerol in CaCo-2 cells transfected with intestinal fatty acid-binding protein. Lipids 2002; 37:61-8. [PMID: 11876264 DOI: 10.1007/s11745-002-0864-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The fatty acid-binding proteins are hypothesized to be involved in cellular fatty acid transport and trafficking. We established CaCo-2 cells stably transfected with intestinal fatty acid-binding protein (I-FABP) and examined how the expression of this protein may influence fatty acid metabolism. I-FABP expression was detectable in I-FABP-transfected cells, whereas parent CaCo-2 cells as well as mock-transfected cells failed to express detectable levels of I-FABP mRNA or protein at any stage of differentiation. For studies of lipid metabolism, cells were incubated with [14C]oleic acid in taurocholate micelles containing monoolein, and distribution of labeled fatty acid in cellular and secreted lipids was examined. In one transfected cell clone, expressing the highest level of I-FABP, labeled cellular triacylglycerol increased approximately twofold as compared to control cells. The level of intracellular triacylglycerol in two other I-FABP-transfected clones resembled that of control cells. However, secretion of triacylglycerol was markedly reduced in all the I-FABP-expressing cell lines. Our data suggest that increased expression of I-FABP leads to reduced triacylglycerol secretion in intestinal cells.
Collapse
Affiliation(s)
- Ane Gedde-Dahl
- Department of Pharmacology, School of Pharmacy, University of Oslo, Norway.
| | | | | | | | | |
Collapse
|
14
|
Ho SY, Storch J. Common mechanisms of monoacylglycerol and fatty acid uptake by human intestinal Caco-2 cells. Am J Physiol Cell Physiol 2001; 281:C1106-17. [PMID: 11546646 DOI: 10.1152/ajpcell.2001.281.4.c1106] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Free fatty acids (FFA) and sn-2-monoacylglycerol (sn-2-MG), the two hydrolysis products of dietary triacylglycerol, are absorbed from the lumen into polarized enterocytes that line the small intestine. Intensive studies regarding FFA transport across the brush-border membrane of the enterocyte are available; however, little is known about sn-2-MG transport. We therefore studied the kinetics of sn-2-MG transport, compared with those of long-chain FFA (LCFA), by human intestinal Caco-2 cells. To mimic postprandial luminal and plasma environments, we examined the uptake of taurocholate-mixed lipids and albumin-bound lipids at the apical (AP) and basolateral (BL) surfaces of Caco-2 cells, respectively. The results demonstrate that the uptake of sn-2-monoolein at both the AP and BL membranes appears to be a saturable function of the monomer concentration of sn-2-monoolein. Furthermore, trypsin preincubation inhibits sn-2-monoolein uptake at both AP and BL poles of cells. These results suggest that sn-2-monoolein uptake may be a protein-mediated process. Competition studies also support a protein-mediated mechanism and indicate that LCFA and LCMG may compete through the same membrane protein(s) at the AP surface of Caco-2 cells. The plasma membrane fatty acid-binding protein (FABP(pm)) is known to be expressed in Caco-2, and here we demonstrate that fatty acid transport protein (FATP) is also expressed. These putative plasma membrane LCFA transporters may be involved in the uptake of sn-2-monoolein into Caco-2 cells.
Collapse
Affiliation(s)
- S Y Ho
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey 08901-8525, USA
| | | |
Collapse
|
15
|
Storch J, Thumser AE. The fatty acid transport function of fatty acid-binding proteins. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1486:28-44. [PMID: 10856711 DOI: 10.1016/s1388-1981(00)00046-9] [Citation(s) in RCA: 331] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The intracellular fatty acid-binding proteins (FABPs) comprise a family of 14-15 kDa proteins which bind long-chain fatty acids. A role for FABPs in fatty acid transport has been hypothesized for several decades, and the accumulated indirect and correlative evidence is largely supportive of this proposed function. In recent years, a number of experimental approaches which more directly examine the transport function of FABPs have been taken. These include molecular level in vitro modeling of fatty acid transfer mechanisms, whole cell studies of fatty acid uptake and intracellular transfer following genetic manipulation of FABP type and amount, and an examination of cells and tissues from animals engineered to lack expression of specific FABPs. Collectively, data from these studies have provided strong support for defining the FABPs as fatty acid transport proteins. Further studies are necessary to elucidate the fundamental mechanisms by which cellular fatty acid trafficking is modulated by the FABPs.
Collapse
Affiliation(s)
- J Storch
- Department of Nutritional Sciences, Cook College, Rutgers University, New Brunswick, NJ 08901-8525,USA.
| | | |
Collapse
|
16
|
Darimont C, Gradoux N, Persohn E, Cumin F, De Pover A. Effects of intestinal fatty acid-binding protein overexpression on fatty acid metabolism in Caco-2 cells. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32077-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
17
|
Darimont C, Gradoux N, de Pover A. Epidermal growth factor regulates fatty acid uptake and metabolism in Caco-2 cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:G606-12. [PMID: 10070036 DOI: 10.1152/ajpgi.1999.276.3.g606] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Epidermal growth factor (EGF) has been reported to stimulate carbohydrate, amino acid, and electrolyte transport in the small intestine, but its effects on lipid transport are poorly documented. This study aimed to investigate EGF effects on fatty acid uptake and esterification in a human enterocyte cell line (Caco-2). EGF inhibited cell uptake of [14C]palmitate and markedly reduced its incorporation into triglycerides. In contrast, the incorporation in phospholipids was enhanced. To elucidate the mechanisms involved, key steps of lipid synthesis were investigated. The amount of intestinal fatty acid-binding protein (I-FABP), which is thought to be important for fatty acid absorption, and the activity of diacylglycerol acyltransferase (DGAT), an enzyme at the branch point of diacylglycerol utilization, were reduced. EGF effects on DGAT and on palmitate esterification occurred at 2-10 ng/ml, whereas effects on I-FABP and palmitate uptake occurred only at 10 ng/ml. This suggests that EGF inhibited palmitate uptake by reducing the I-FABP level and shifted its utilization from triglycerides to phospholipids by inhibiting DGAT. This increase in phospholipid synthesis might play a role in the restoration of enterocyte absorption function after intestinal mucosa injury.
Collapse
Affiliation(s)
- C Darimont
- Metabolic and Cardiovascular Diseases, Novartis Pharma AG, CH-4002 Basel, Switzerland
| | | | | |
Collapse
|
18
|
Horrobin DF, Bennett CN. New gene targets related to schizophrenia and other psychiatric disorders: enzymes, binding proteins and transport proteins involved in phospholipid and fatty acid metabolism. Prostaglandins Leukot Essent Fatty Acids 1999; 60:141-67. [PMID: 10359017 DOI: 10.1054/plef.1999.0027] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phospholipids make up about 60% of the brain's dry weight. In spite of this, phospholipid metabolism has received relatively little attention from those seeking genetic factors involved in psychiatric and neurological disorders. However, there is now increasing evidence from many quarters that abnormal phospholipid and related fatty acid metabolism may contribute to illnesses such as schizophrenia, bipolar disorder, depression and attention deficit hyperactivity disorder. To date the possible specific proteins and genes involved have been relatively ill-defined. This paper reviews the main pathways of phospholipid metabolism, emphasizing the roles of phospholipases of the A2 and C series in signal transduction processes. It identifies some likely protein candidates for involvement in psychiatric and neurological disorders. It also reviews the chromosomal locations of regions likely to be involved in these disorders, and relates these to the known locations of genes directly or indirectly involved in phospholipid and fatty acid metabolism.
Collapse
Affiliation(s)
- D F Horrobin
- Laxdale Research, Kings Park House, Laurelhill Business Park, Stirling, UK
| | | |
Collapse
|