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Seessle J, Liebisch G, Staffer S, Tuma-Kellner S, Merle U, Herrmann T, Chamulitrat W. Enterocyte-specific FATP4 deficiency elevates blood lipids via a shift from polar to neutral lipids in distal intestine. Am J Physiol Gastrointest Liver Physiol 2024; 327:G202-G216. [PMID: 38915276 DOI: 10.1152/ajpgi.00109.2024] [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: 04/11/2024] [Revised: 06/13/2024] [Accepted: 06/20/2024] [Indexed: 06/26/2024]
Abstract
Fatty acid transport protein (FATP)4 was thought to mediate intestinal lipid absorption, which was disputed by a study using keratinocyte-Fatp4-rescued Fatp4-/- mice. These knockouts when fed with a Western diet showed elevated intestinal triglyceride (TG) and fatty acid levels. To investigate a possible role of FATP4 on intestinal lipid processing, ent-Fatp4 (KO) mice were generated by Villin-Cre-specific inactivation of the Fatp4 gene. We aimed to measure circulating and intestinal lipids in control and KO mice after acute or chronic fat intake or during aging. Remarkably, ent-Fatp4 mice displayed an approximately 30% decrease in ileal behenic, lignoceric, and nervonic acids, ceramides containing these FA, as well as, ileal sphingomyelin, phosphatidylcholine, and phosphatidylinositol levels. Such decreases were concomitant with an increase in jejunal cholesterol ester. After a 2-wk recovery from high lipid overload by tyloxapol and oral-lipid treatment, ent-Fatp4 mice showed an increase in plasma TG and chylomicrons. Upon overnight fasting followed by an oral fat meal, ent-Fatp4 mice showed an increase in plasma TG-rich lipoproteins and the particle number of chylomicrons and very low-density lipoproteins. During aging or after feeding with a high-fat high-cholesterol (HFHC) diet, ent-Fatp4 mice showed an increase in plasma TG, fatty acids, glycerol, and lipoproteins as well as intestinal lipids. HFHC-fed KO mice displayed an increase in body weight, the number of lipid droplets with larger sizes in the ileum, concomitant with a decrease in ileal ceramides and phosphatidylcholine. Thus, enterocyte FATP4 deficiency led to a metabolic shift from polar to neutral lipids in distal intestine rendering an increase in plasma lipids and lipoproteins.NEW & NOTEWORTHY Enterocyte-specific Fatp4 deficiency in mice increased intestinal lipid absorption with elevation of blood lipids during fasting and aging, as well as after an acute oral fat-loading or chronic HFHC feeding. Lipidomics revealed that knockout mice displayed a shift from very long-chain to long-chain fatty acids, and from polar to neutral lipids, predominantly in the ileum. Thus, FATP4 may have a physiological function in the control of blood lipids via metabolic shifts in distal intestine.
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Affiliation(s)
- Jessica Seessle
- Department of Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
| | - Gerhard Liebisch
- Institute of Clinical Chemistry and Laboratory Medicine, University of Regensburg, Regensburg, Germany
| | - Simone Staffer
- Department of Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
| | - Sabine Tuma-Kellner
- Department of Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
| | - Uta Merle
- Department of Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
| | - Thomas Herrmann
- Department of Medical Clinic 1, Westkuesten Hospital, Heide, Germany
| | - Walee Chamulitrat
- Department of Internal Medicine IV, University Hospital Heidelberg, Heidelberg, Germany
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2
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Zhang F, Hanif Q, Luo X, Jin X, Zhang J, He Z, Lei C, Liu J, Huang B, Qu K. Muscle transcriptome analysis reveal candidate genes and pathways related to fat and lipid metabolism in Yunling cattle. Anim Biotechnol 2023; 34:1022-1029. [PMID: 34874232 DOI: 10.1080/10495398.2021.2009846] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Yunling cattle (YL) is a recently developed beef breed harboring a quarter of Yunnan ancestral cattle genome, spanning over past 30 years. Compared with Diqing cattle (DQ), a Yunnan native cattle breed, YL presents various advantages, including rapid growth and exquisite meat quality. However, the molecular mechanisms underlying these phenotypic differences are not clearly understood. To further identify the candidate genes responsible for the quality of the meat in the muscle, longissimus dorsi (LD) muscle was used for RNA-Seq analysis. A total of 508 differentially expressed genes (DEGs) were identified in YL (adjusted p-value <0.01 and log2FoldChange >1), of which 243 were up-regulated and 265 were down-regulated. Functional association analysis showed that the identified DEGs mainly enriched the lipid and fat metabolism pathways. Moreover, it was also observed that several fat-related genes were differentially expressed in both cattle breeds, including three up-regulated genes (MOGAT1, ACSM3, PLPP2) and two down-regulated genes (ADIG, GPAT3). In addition, alternative splice analysis was also performed revealing an important 9-11 exon skipping variation of GPAM gene (crucial for beef marbling) in YL, which is three times higher than that in DQ, suggesting that this variation might have played the central role in the 'snow beef' effect in YL. We believe that our results will help in understanding the mechanism of muscle development and promote the further breeding programs in YL cattle.
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Affiliation(s)
- Fengwei Zhang
- Academy of Science and Technology, Chuxiong Normal University, Chuxiong, Yunnan, China
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Quratulain Hanif
- National Institute for Biotechnology and Genetic Engineering, Pakistan Institute of Engineering and Applied Sciences, Faisalabad, Pakistan
| | - Xiaoyu Luo
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Xiandong Jin
- Yunnan Animal Husbandry Station, Kunming, Yunnan, China
| | - Jicai Zhang
- Yunnan Academy of Grassland and Animal Science, Kunming, Yunnan, China
| | - Zhanxing He
- Yunnan Academy of Grassland and Animal Science, Kunming, Yunnan, China
| | - Chuzhao Lei
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Jianyong Liu
- Yunnan Academy of Grassland and Animal Science, Kunming, Yunnan, China
| | - Bizhi Huang
- Yunnan Academy of Grassland and Animal Science, Kunming, Yunnan, China
| | - Kaixing Qu
- Academy of Science and Technology, Chuxiong Normal University, Chuxiong, Yunnan, China
- Yunnan Academy of Grassland and Animal Science, Kunming, Yunnan, China
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Wang Y, Wang X, Luo Y, Zhang J, Lin Y, Wu J, Zeng B, Liu L, Yan P, Liang J, Guo H, Jin L, Tang Q, Long K, Li M. Spatio-temporal transcriptome dynamics coordinate rapid transition of core crop functions in 'lactating' pigeon. PLoS Genet 2023; 19:e1010746. [PMID: 37289658 PMCID: PMC10249823 DOI: 10.1371/journal.pgen.1010746] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 04/14/2023] [Indexed: 06/10/2023] Open
Abstract
Pigeons (Columba livia) are among a select few avian species that have developed a specialized reproductive mode wherein the parents produce a 'milk' in their crop to feed newborn squabs. Nonetheless, the transcriptomic dynamics and role in the rapid transition of core crop functions during 'lactation' remain largely unexplored. Here, we generated a de novo pigeon genome assembly to construct a high resolution spatio-temporal transcriptomic landscape of the crop epithelium across the entire breeding stage. This multi-omics analysis identified a set of 'lactation'-related genes involved in lipid and protein metabolism, which contribute to the rapid functional transitions in the crop. Analysis of in situ high-throughput chromatin conformation capture (Hi-C) sequencing revealed extensive reorganization of promoter-enhancer interactions linked to the dynamic expression of these 'lactation'-related genes between stages. Moreover, their expression is spatially localized in specific epithelial layers, and can be correlated with phenotypic changes in the crop. These results illustrate the preferential de novo synthesis of 'milk' lipids and proteins in the crop, and provides candidate enhancer loci for further investigation of the regulatory elements controlling pigeon 'lactation'.
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Affiliation(s)
- Yujie Wang
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Xun Wang
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
- Animal Breeding and Genetics Key Laboratory of Sichuan Province, Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Yi Luo
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jiaman Zhang
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Yu Lin
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jie Wu
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Bo Zeng
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
- Animal Breeding and Genetics Key Laboratory of Sichuan Province, Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Lei Liu
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Peiqi Yan
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Jiyuan Liang
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Hongrui Guo
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Long Jin
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
- Animal Breeding and Genetics Key Laboratory of Sichuan Province, Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Qianzi Tang
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
- Animal Breeding and Genetics Key Laboratory of Sichuan Province, Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Keren Long
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
- Animal Breeding and Genetics Key Laboratory of Sichuan Province, Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
| | - Mingzhou Li
- Livestock and Poultry Multi-omics Key Laboratory of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
- Animal Breeding and Genetics Key Laboratory of Sichuan Province, Institute of Animal Genetics and Breeding, Sichuan Agricultural University, Chengdu, China
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4
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Fan G, Li Y, Zong Y, Suo X, Jia Y, Gao M, Yang X. GPAT3 regulates the synthesis of lipid intermediate LPA and exacerbates Kupffer cell inflammation mediated by the ERK signaling pathway. Cell Death Dis 2023; 14:208. [PMID: 36964139 PMCID: PMC10039030 DOI: 10.1038/s41419-023-05741-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/09/2023] [Accepted: 03/14/2023] [Indexed: 03/26/2023]
Abstract
In the process of inflammatory activation, macrophages exhibit lipid metabolism disorders and accumulate lipid droplets. Kupffer cells (KCs) are the resident hepatic macrophage with critical defense functions in the pathogenesis of several types of liver disease. How dysregulated lipid metabolism contributes to perturbed KCs functions remains elusive. Here we report that glycerol-3-phosphate acyltransferase 3 (GPAT3) plays a key role in KCs inflammation response. Our findings indicate that lipopolysaccharide (LPS)-mediated inflammatory activation markedly increased lipid droplets (LDs) accumulation in KCs. This increase could be attributed to significantly up-regulated GPAT3. The loss of GPAT3 function obviously reduced KCs inflammation reaction both in vivo and in vitro, and was accompanied by improved mitochondrial function and decreased production of lysophosphatidic acid (LPA), in turn inhibiting extracellular regulated protein kinases (ERK) signaling pathway. Overall, this study highlights the role of GPAT3 in inflammatory activation of KCs and could thus be a potential therapeutic target for the treatment of inflammation-related liver disease.
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Affiliation(s)
- Guoqiang Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Yanfei Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Yibo Zong
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Xiaoyi Suo
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Yimin Jia
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing, 210095, P. R. China
| | - Mingming Gao
- Laboratory of Lipid Metabolism, Hebei Medical University, Shijiazhuang, Hebei, 050017, China
| | - Xiaojing Yang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Nanjing Agricultural University, Nanjing, 210095, P. R. China.
- Key Laboratory of Animal Physiology & Biochemistry, Nanjing Agricultural University, Nanjing, 210095, P. R. China.
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5
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Chen X, Chen Y, Liu Y, Zou L, McClements DJ, Liu W. A review of recent progress in improving the bioavailability of nutraceutical-loaded emulsions after oral intake. Compr Rev Food Sci Food Saf 2022; 21:3963-4001. [PMID: 35912644 DOI: 10.1111/1541-4337.13017] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/27/2022] [Accepted: 07/08/2022] [Indexed: 01/28/2023]
Abstract
Increasing awareness of the health benefits of specific constituents in fruits, vegetables, cereals, and other whole foods has sparked a broader interest in the potential health benefits of nutraceuticals. Many nutraceuticals are hydrophobic substances, which means they must be encapsulated in colloidal delivery systems. Oil-in-water emulsions are one of the most widely used delivery systems for improving the bioavailability and bioactivity of these nutraceuticals. The composition and structure of emulsions can be designed to improve the water dispersibility, physicochemical stability, and bioavailability of the encapsulated nutraceuticals. The nature of the emulsion used influences the interfacial area and properties of the nutraceutical-loaded oil droplets in the gastrointestinal tract, which influences their digestion, as well as the bioaccessibility, metabolism, and absorption of the nutraceuticals. In this article, we review recent in vitro and in vivo studies on the utilization of emulsions to improve the bioavailability of nutraceuticals. The findings from this review should facilitate the design of more efficacious nutraceutical-loaded emulsions with increased bioactivity.
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Affiliation(s)
- Xing Chen
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Yan Chen
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Yikun Liu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - Liqiang Zou
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
| | - David Julian McClements
- Biopolymers & Colloids Research Laboratory, Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Wei Liu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China
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6
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Ghanem M, Lewis GF, Xiao C. Recent advances in cytoplasmic lipid droplet metabolism in intestinal enterocyte. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159197. [PMID: 35820577 DOI: 10.1016/j.bbalip.2022.159197] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 06/03/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
Processing of dietary fats in the intestine is a highly regulated process that influences whole-body energy homeostasis and multiple physiological functions. Dysregulated lipid handling in the intestine leads to dyslipidemia and atherosclerotic cardiovascular disease. In intestinal enterocytes, lipids are incorporated into lipoproteins and cytoplasmic lipid droplets (CLDs). Lipoprotein synthesis and CLD metabolism are inter-connected pathways with multiple points of regulation. This review aims to highlight recent advances in the regulatory mechanisms of lipid processing in the enterocyte, with particular focus on CLDs. In-depth understanding of the regulation of lipid metabolism in the enterocyte may help identify therapeutic targets for the treatment and prevention of metabolic disorders.
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Affiliation(s)
- Murooj Ghanem
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology, University of Toronto, and University Health Network, Toronto, ON, Canada
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
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7
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Stone SJ. Mechanisms of intestinal triacylglycerol synthesis. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159151. [PMID: 35296424 DOI: 10.1016/j.bbalip.2022.159151] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/13/2022] [Accepted: 02/16/2022] [Indexed: 02/07/2023]
Abstract
Triacylglycerols are a major source of stored energy that are obtained either from the diet or can be synthesized to some extent by most tissues. Alterations in pathways of triacylglycerol metabolism can result in their excessive accumulation leading to obesity, insulin resistance, cardiovascular disease and nonalcoholic fatty liver disease. Most tissues in mammals synthesize triacylglycerols via the glycerol 3-phosphate pathway. However, in the small intestine the monoacylglycerol acyltransferase pathway is the predominant pathway for triacylglycerol biosynthesis where it participates in the absorption of dietary triacylglycerol. In this review, the enzymes that are part of both the glycerol 3-phosphate and monoacylglycerol acyltransferase pathways and their contributions to intestinal triacylglycerol metabolism are reviewed. The potential of some of the enzymes involved in triacylglycerol synthesis in the small intestine as possible therapeutic targets for treating metabolic disorders associated with elevated triacylglycerol is briefly discussed.
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Affiliation(s)
- Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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8
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Steenson S, Shojaee-Moradie F, Lovegrove JA, Umpleby AM, Jackson KG, Fielding BA. Dose Dependent Effects of Fructose and Glucose on de novo Palmitate and Glycerol Synthesis in an Enterocyte Cell Model. Mol Nutr Food Res 2021; 66:e2100456. [PMID: 34787358 DOI: 10.1002/mnfr.202100456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/10/2021] [Indexed: 11/11/2022]
Abstract
SCOPE Fructose exacerbates post-prandial hypertriacylglycerolaemia; perhaps partly due to increased enterocyte de novo lipogenesis (DNL). It is unknown whether this is concentration-dependent or if fructose has a greater effect on lipid synthesis than glucose. Dose-dependent effects of fructose and glucose on DNL and de novo triacylglycerol (TAG)-glycerol synthesis are investigated in a Caco-2 cell model. METHODS AND RESULTS Caco-2 cells are treated for 96 h with 5, 25, or 50 mM fructose or glucose, or 12.5 mM fructose/12.5 mM glucose mix. DNL is measured following addition of [13 C2 ]-acetate to apical media. Separately, [13 C6 ]-fructose and [13 C6 ]-glucose are used to measure DNL and de novo TAG-glycerol synthesis. DNL from [13 C2 ]-acetate is detected following all treatments, with greater amounts in intracellular than secreted (media) samples (all p < 0.05). DNL from [13 C6 ]-fructose and [13 C6 ]-glucose is also measurable. Intracellular synthesis is concentration-dependent for both glucose (p = 0.003) and fructose (p = 0.034) tracers and is higher with 25 mM glucose than 25 mM fructose (p = 0.025). DNL from fructose and glucose is <1%, but up to 70% of de novo TAG-glycerol is synthesized from glucose or fructose. CONCLUSION Fructose is not a major source of DNL in Caco-2 cells but contributes substantially to de novo TAG-glycerol synthesis.
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Affiliation(s)
- Simon Steenson
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7WG, UK.,Hugh Sinclair Unit of Human Nutrition, Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading, RG6 6DZ, UK
| | - Fariba Shojaee-Moradie
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7WG, UK
| | - Julie A Lovegrove
- Hugh Sinclair Unit of Human Nutrition, Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading, RG6 6DZ, UK
| | - A Margot Umpleby
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7WG, UK
| | - Kim G Jackson
- Hugh Sinclair Unit of Human Nutrition, Department of Food & Nutritional Sciences and Institute for Cardiovascular and Metabolic Research (ICMR), University of Reading, Reading, RG6 6DZ, UK
| | - Barbara A Fielding
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7WG, UK
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Wang B, Zhao X, Li Z, Luo H, Zhang H, Guo Y, Zhang C, Ma Q. Changes of Metabolites and Gene Expression under Different Feeding Systems Associated with Lipid Metabolism in Lamb Meat. Foods 2021; 10:foods10112612. [PMID: 34828897 PMCID: PMC8619812 DOI: 10.3390/foods10112612] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/23/2021] [Accepted: 10/26/2021] [Indexed: 01/12/2023] Open
Abstract
The effects of the different feeding systems, graze feeding (GSF), time-limited graze feeding (GF), and stall-feeding (SF)) on the fatty acid content, metabolites, and genes expression of the longissimus dorsi (LD) in Tan lambs were investigated in the present study. Thirty-nine 4-month-old male Tan lambs with similar body weight (24.91 ± 1.74 kg) were selected and divided into the three feeding systems (n = 13) randomly. Lambs were slaughtered after 83 days of the feeding trails, and LD muscle samples were collected for further analysis. The results indicated that different feeding systems have no significant effect on short-chain fatty acids in Tan lambs (p > 0.05). However, the total saturated fatty acids (∑SFA) and monounsaturated fatty acids (∑MUFA) in the GSF and GF groups were lower than those in the SF group (p < 0.001). The total polyunsaturated fatty acids (∑PUFA) in the GSF group were higher than those in the GF and SF groups (p < 0.001). Moreover, in the comparison of both GF vs GSF groups and SF vs GSF groups, metabolomic analysis showed that metabolites such as cis-(6,9,12)-linolenic acid, arachidic acid, acetylcarnitine, and L-carnitine with lower concentration were significantly enriched in the biosynthesis of unsaturated fatty acid pathway (p < 0.05), but metabolites such as phosphorylcholine, glycerophosphocholine, cytidine 5'-diphosphocholine, and glycerol-3-phosphate with higher concentrations were enriched in the glycerophospholipid metabolism pathway. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis of the results indicated that in the comparison of the GSF group with the SF group, differentially expressed genes (DEGs) such as LIPC, ERFE, FABP3, PLA2R1, LDLR, and SLC10A6, were enriched in the steroid biosynthesis and cholesterol metabolism pathways. In addition, differential metabolites and genes showed a significant correlation with the content of ∑SFA, ∑MUFA, and ∑PUFA in lamb meat (p < 0.05). These findings demonstrated that the feeding system was an important factor in regulating fatty acid content by affecting lipid-metabolism-related metabolites and gene expression in muscle, and graze-feeding system provided lamb meat with higher ∑PUFA content than time-limited-grazing and stall-feeding systems.
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Affiliation(s)
- Bo Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (B.W.); (X.Z.); (Z.L.); (Y.G.); (C.Z.)
| | - Xingang Zhao
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (B.W.); (X.Z.); (Z.L.); (Y.G.); (C.Z.)
| | - Zhen Li
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (B.W.); (X.Z.); (Z.L.); (Y.G.); (C.Z.)
| | - Hailing Luo
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (B.W.); (X.Z.); (Z.L.); (Y.G.); (C.Z.)
- Correspondence: ; Tel./Fax: +86-010-62734597
| | - Hao Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China;
| | - Yanping Guo
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (B.W.); (X.Z.); (Z.L.); (Y.G.); (C.Z.)
| | - Can Zhang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China; (B.W.); (X.Z.); (Z.L.); (Y.G.); (C.Z.)
| | - Qing Ma
- Research Center of Grass and Livestock, Ningxia Academy of Agriculture and Forestry Science, Yinchuan 750002, China;
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10
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Zembroski AS, Xiao C, Buhman KK. The Roles of Cytoplasmic Lipid Droplets in Modulating Intestinal Uptake of Dietary Fat. Annu Rev Nutr 2021; 41:79-104. [PMID: 34283920 DOI: 10.1146/annurev-nutr-110320-013657] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dietary fat absorption is required for health but also contributes to hyperlipidemia and metabolic disease when dysregulated. One step in the process of dietary fat absorption is the formation of cytoplasmic lipid droplets (CLDs) in small intestinal enterocytes; these CLDs serve as dynamic triacylglycerol storage organelles that influence the rate at which dietary fat is absorbed. Recent studies have uncovered novel factors regulating enterocyte CLD metabolism that in turn influence the absorption of dietary fat. These include peroxisome proliferator-activated receptor α activation, compartmentalization of different lipid pools, the gut microbiome, liver X receptor and farnesoid X receptor activation, obesity, and physiological factors stimulating CLD mobilization. Understanding how enterocyte CLD metabolism is regulated is key in modulating the absorption of dietary fat in the prevention of hyperlipidemia and its associated metabolic disorders. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Alyssa S Zembroski
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Changting Xiao
- Department of Anatomy, Physiology and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana 47907, USA;
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11
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Reilly SM, Hung CW, Ahmadian M, Zhao P, Keinan O, Gomez AV, DeLuca JH, Dadpey B, Lu D, Zaid J, Poirier B, Peng X, Yu RT, Downes M, Liddle C, Evans RM, Murphy AN, Saltiel AR. Catecholamines suppress fatty acid re-esterification and increase oxidation in white adipocytes via STAT3. Nat Metab 2020; 2:620-634. [PMID: 32694788 PMCID: PMC7384260 DOI: 10.1038/s42255-020-0217-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 04/30/2020] [Indexed: 12/12/2022]
Abstract
Catecholamines stimulate the mobilization of stored triglycerides in adipocytes to provide fatty acids (FAs) for other tissues. However, a large proportion is taken back up and either oxidized or re-esterified. What controls the disposition of these FAs in adipocytes remains unknown. Here, we report that catecholamines redirect FAs for oxidation through the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Adipocyte STAT3 is phosphorylated upon activation of β-adrenergic receptors, and in turn suppresses FA re-esterification to promote FA oxidation. Adipocyte-specific Stat3 KO mice exhibit normal rates of lipolysis, but exhibit defective lipolysis-driven oxidative metabolism, resulting in reduced energy expenditure and increased adiposity when they are on a high-fat diet. This previously unappreciated, non-genomic role of STAT3 explains how sympathetic activation can increase both lipolysis and FA oxidation in adipocytes, revealing a new regulatory axis in metabolism.
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Affiliation(s)
- Shannon M Reilly
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
| | - Chao-Wei Hung
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Maryam Ahmadian
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Peng Zhao
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Omer Keinan
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Andrew V Gomez
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Julia H DeLuca
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Benyamin Dadpey
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Donald Lu
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jessica Zaid
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - BreAnne Poirier
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaoling Peng
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Ruth T Yu
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Christopher Liddle
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Ronald M Evans
- Gene Expression Laboratory, Salk Institute for Biological Sciences, La Jolla, CA, USA
| | - Anne N Murphy
- Department of Pharmacology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Cytokinetics, South San Francisco, CA, USA
| | - Alan R Saltiel
- Division of Metabolism and Endocrinology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Pharmacology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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12
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Stahel P, Xiao C, Nahmias A, Lewis GF. Role of the Gut in Diabetic Dyslipidemia. Front Endocrinol (Lausanne) 2020; 11:116. [PMID: 32231641 PMCID: PMC7083132 DOI: 10.3389/fendo.2020.00116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/21/2020] [Indexed: 12/13/2022] Open
Abstract
Type 2 diabetes (T2D) is associated with increased risk of cardiovascular disease (CVD). In insulin resistant states such as the metabolic syndrome, overproduction and impaired clearance of liver-derived very-low-density lipoproteins and gut-derived chylomicrons (CMs) contribute to hypertriglyceridemia and elevated atherogenic remnant lipoproteins. Although ingested fat is the major stimulus of CM secretion, intestinal lipid handling and ultimately CM secretory rate is determined by numerous additional regulatory inputs including nutrients, hormones and neural signals that fine tune CM secretion during fasted and fed states. Insulin resistance and T2D represent perturbed metabolic states in which intestinal sensitivity to key regulatory hormones such as insulin, leptin and glucagon-like peptide-1 (GLP-1) may be altered, contributing to increased CM secretion. In this review, we describe the evidence from human and animal models demonstrating increased CM secretion in insulin resistance and T2D and discuss the molecular mechanisms underlying these effects. Several novel compounds are in various stages of preclinical and clinical investigation to modulate intestinal CM synthesis and secretion. Their efficacy, safety and therapeutic utility are discussed. Similarly, the effects of currently approved lipid modulating therapies such as statins, ezetimibe, fibrates, and PCSK9 inhibitors on intestinal CM production are discussed. The intricacies of intestinal CM production are an active area of research that may yield novel therapies to prevent atherosclerotic CVD in insulin resistance and T2D.
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13
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Lee J, Ridgway ND. Substrate channeling in the glycerol-3-phosphate pathway regulates the synthesis, storage and secretion of glycerolipids. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158438. [PMID: 30959116 DOI: 10.1016/j.bbalip.2019.03.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 01/16/2023]
Abstract
The successive acylation of glycerol-3-phosphate (G3P) by glycerol-3-phosphate acyltransferases and acylglycerol-3-phosphate acyltransferases produces phosphatidic acid (PA), a precursor for CDP-diacylglycerol-dependent phospholipid synthesis. PA is further dephosphorylated by LIPINs to produce diacylglycerol (DG), a substrate for the synthesis of triglyceride (TG) by DG acyltransferases and a precursor for phospholipid synthesis via the CDP-choline and CDP-ethanolamine (Kennedy) pathways. The channeling of fatty acids into TG for storage in lipid droplets and secretion in lipoproteins or phospholipids for membrane biogenesis is dependent on isoform expression, activity and localization of G3P pathway enzymes, as well as dietary and hormonal and tissue-specific factors. Here, we review the mechanisms that control partitioning of substrates into lipid products of the G3P pathway.
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Affiliation(s)
- Jonghwa Lee
- Atlantic Research Center, Depts. of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Neale D Ridgway
- Atlantic Research Center, Depts. of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada.
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14
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Zhang P, Csaki LS, Ronquillo E, Baufeld LJ, Lin JY, Gutierrez A, Dwyer JR, Brindley DN, Fong LG, Tontonoz P, Young SG, Reue K. Lipin 2/3 phosphatidic acid phosphatases maintain phospholipid homeostasis to regulate chylomicron synthesis. J Clin Invest 2018; 129:281-295. [PMID: 30507612 DOI: 10.1172/jci122595] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/09/2018] [Indexed: 12/31/2022] Open
Abstract
The lipin phosphatidic acid phosphatase (PAP) enzymes are required for triacylglycerol (TAG) synthesis from glycerol 3-phosphate in most mammalian tissues. The 3 lipin proteins (lipin 1, lipin 2, and lipin 3) each have PAP activity, but have distinct tissue distributions, with lipin 1 being the predominant PAP enzyme in many metabolic tissues. One exception is the small intestine, which is unique in expressing exclusively lipin 2 and lipin 3. TAG synthesis in small intestinal enterocytes utilizes 2-monoacylglycerol and does not require the PAP reaction, making the role of lipin proteins in enterocytes unclear. Enterocyte TAGs are stored transiently as cytosolic lipid droplets or incorporated into lipoproteins (chylomicrons) for secretion. We determined that lipin enzymes are critical for chylomicron biogenesis, through regulation of membrane phospholipid composition and association of apolipoprotein B48 with nascent chylomicron particles. Lipin 2/3 deficiency caused phosphatidic acid accumulation and mammalian target of rapamycin complex 1 (mTORC1) activation, which were associated with enhanced protein levels of a key phospholipid biosynthetic enzyme (CTP:phosphocholine cytidylyltransferase α) and altered membrane phospholipid composition. Impaired chylomicron synthesis in lipin 2/3 deficiency could be rescued by normalizing phospholipid synthesis levels. These data implicate lipin 2/3 as a control point for enterocyte phospholipid homeostasis and chylomicron biogenesis.
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Affiliation(s)
- Peixiang Zhang
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Lauren S Csaki
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Emilio Ronquillo
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Lynn J Baufeld
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jason Y Lin
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Alexis Gutierrez
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jennifer R Dwyer
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - David N Brindley
- Signal Transduction Research Group, Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Loren G Fong
- Department of Medicine, Division of Cardiology, and
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
| | - Stephen G Young
- Department of Medicine, Division of Cardiology, and.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
| | - Karen Reue
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.,Molecular Biology Institute, UCLA, Los Angeles, California, USA
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15
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Xiao C, Stahel P, Lewis GF. Regulation of Chylomicron Secretion: Focus on Post-Assembly Mechanisms. Cell Mol Gastroenterol Hepatol 2018; 7:487-501. [PMID: 30819663 PMCID: PMC6396431 DOI: 10.1016/j.jcmgh.2018.10.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/23/2018] [Accepted: 10/25/2018] [Indexed: 02/06/2023]
Abstract
Rapid and efficient digestion and absorption of dietary triglycerides and other lipids by the intestine, the packaging of those lipids into lipoprotein chylomicron (CM) particles, and their secretion via the lymphatic duct into the blood circulation are essential in maintaining whole-body lipid and energy homeostasis. Biosynthesis and assembly of CMs in enterocytes is a complex multistep process that is subject to regulation by intracellular signaling pathways as well as by hormones, nutrients, and neural factors extrinsic to the enterocyte. Dysregulation of this process has implications for health and disease, contributing to dyslipidemia and a potentially increased risk of atherosclerotic cardiovascular disease. There is increasing recognition that, besides intracellular regulation of CM assembly and secretion, regulation of postassembly pathways also plays important roles in CM secretion. This review examines recent advances in our understanding of the regulation of CM secretion in relation to mobilization of intestinal lipid stores, drawing particular attention to post-assembly regulatory mechanisms, including intracellular trafficking of triglycerides in enterocytes, CM mobilization from the lamina propria, and regulated transport of CM by intestinal lymphatics.
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Affiliation(s)
- Changting Xiao
- Changting Xiao, PhD, Princess Margaret Cancer Research Tower 10-203, Medical and Related Science Centre, 101 College Street, Toronto, Ontario M5G 1L7, Canada. fax: (416) 581-7487.
| | | | - Gary F. Lewis
- Correspondence Address correspondence to: Gary F. Lewis, MD, FRCPC, Toronto General Hospital, 200 Elizabeth Street, EN12-218, Toronto, Ontario M5G 2C4, Canada. fax: (416) 340-3314.
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16
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Aguayo-Orozco A, Bois FY, Brunak S, Taboureau O. Analysis of Time-Series Gene Expression Data to Explore Mechanisms of Chemical-Induced Hepatic Steatosis Toxicity. Front Genet 2018; 9:396. [PMID: 30279702 PMCID: PMC6153316 DOI: 10.3389/fgene.2018.00396] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 08/30/2018] [Indexed: 12/11/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) represents a wide spectrum of disease, ranging from simple fatty liver through steatosis with inflammation and necrosis to cirrhosis. One of the most challenging problems in biomedical research and within the chemical industry is to understand the underlying mechanisms of complex disease, and complex adverse outcome pathways (AOPs). Based on a set of 28 steatotic chemicals with gene expression data measured on primary hepatocytes at three times (2, 8, and 24 h) and three doses (low, medium, and high), we identified genes and pathways, defined as molecular initiating events (MIEs) and key events (KEs) of steatosis using a combination of a time series and pathway analyses. Among the genes deregulated by these compounds, the study highlighted OSBPL9, ALDH7A1, MYADM, SLC51B, PRDX6, GPAT3, TMEM135, DLGDA5, BCO2, APO10LA, TSPAN6, NEURL1B, and DUSP1. Furthermore, pathway analysis indicated deregulation of pathways related to lipid accumulation, such as fat digestion and absorption, linoleic and linolenic acid metabolism, calcium signaling pathway, fatty acid metabolism, peroxisome, retinol metabolism, and steroid metabolic pathways in a time dependent manner. Such transcription profile analysis can help in the understanding of the steatosis evolution over time generated by chemical exposure.
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Affiliation(s)
- Alejandro Aguayo-Orozco
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Frederic Yves Bois
- Institut National de l'Environnement Industriel et des Risques (INERIS), Unité Modèles pour l'Ecotoxicologie et la Toxicologie (METO), Verneuil en Halatte, France
| | - Søren Brunak
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Olivier Taboureau
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,UMRS 973 INSERM, Université Paris Diderot, Université Sorbonne Paris Cité, Paris, France
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17
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Potts A, Uchida A, Deja S, Berglund ED, Kucejova B, Duarte JA, Fu X, Browning JD, Magnuson MA, Burgess SC. Cytosolic phosphoenolpyruvate carboxykinase as a cataplerotic pathway in the small intestine. Am J Physiol Gastrointest Liver Physiol 2018; 315:G249-G258. [PMID: 29631378 PMCID: PMC6139646 DOI: 10.1152/ajpgi.00039.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cytosolic phosphoenolpyruvate carboxykinase (PEPCK) is a gluconeogenic enzyme that is highly expressed in the liver and kidney but is also expressed at lower levels in a variety of other tissues where it may play adjunct roles in fatty acid esterification, amino acid metabolism, and/or TCA cycle function. PEPCK is expressed in the enterocytes of the small intestine, but it is unclear whether it supports a gluconeogenic rate sufficient to affect glucose homeostasis. To examine potential roles of intestinal PEPCK, we generated an intestinal PEPCK knockout mouse. Deletion of intestinal PEPCK ablated ex vivo gluconeogenesis but did not significantly affect glycemia in chow, high-fat diet, or streptozotocin-treated mice. In contrast, postprandial triglyceride secretion from the intestine was attenuated in vivo, consistent with a role in fatty acid esterification. Intestinal amino acid profiles and 13C tracer appearance into these pools were significantly altered, indicating abnormal amino acid trafficking through the enterocyte. The data suggest that the predominant role of PEPCK in the small intestine of mice is not gluconeogenesis but rather to support nutrient processing, particularly with regard to lipids and amino acids. NEW & NOTEWORTHY The small intestine expresses gluconeogenic enzymes for unknown reasons. In addition to glucose synthesis, the nascent steps of this pathway can be used to support amino acid and lipid metabolisms. When phosphoenolpyruvate carboxykinase, an essential gluconeogenic enzyme, is knocked out of the small intestine of mice, glycemia is unaffected, but mice inefficiently absorb dietary lipid, have abnormal amino acid profiles, and inefficiently catabolize glutamine. Therefore, the initial steps of intestinal gluconeogenesis are used for processing dietary triglycerides and metabolizing amino acids but are not essential for maintaining blood glucose levels.
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Affiliation(s)
- Austin Potts
- 1Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Aki Uchida
- 1Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Stanislaw Deja
- 2Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Eric D. Berglund
- 1Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Blanka Kucejova
- 2Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Joao A. Duarte
- 1Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Xiaorong Fu
- 2Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jeffrey D. Browning
- 3Department of Clinical Nutrition, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mark A. Magnuson
- 5Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Shawn C. Burgess
- 1Advanced Imaging Research Center, The University of Texas Southwestern Medical Center, Dallas, Texas,4Department of Pharmacology, The University of Texas Southwestern Medical Center, Dallas, Texas
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18
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Update on glycerol-3-phosphate acyltransferases: the roles in the development of insulin resistance. Nutr Diabetes 2018; 8:34. [PMID: 29799006 PMCID: PMC5968029 DOI: 10.1038/s41387-018-0045-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 05/03/2018] [Accepted: 05/06/2018] [Indexed: 01/16/2023] Open
Abstract
Glycerol-3-phosphate acyltransferase (GPAT) is the rate-limiting enzyme in the de novo pathway of glycerolipid synthesis. It catalyzes the conversion of glycerol-3-phosphate and long-chain acyl-CoA to lysophosphatidic acid. In mammals, four isoforms of GPATs have been identified based on subcellular localization, substrate preferences, and NEM sensitivity, and they have been classified into two groups, one including GPAT1 and GPAT2, which are localized in the mitochondrial outer membrane, and the other including GPAT3 and GPAT4, which are localized in the endoplasmic reticulum membrane. GPATs play a pivotal role in the regulation of triglyceride and phospholipid synthesis. Through gain-of-function and loss-of-function experiments, it has been confirmed that GPATs play a critical role in the development of obesity, hepatic steatosis, and insulin resistance. In line with this, the role of GPATs in metabolism was supported by studies using a GPAT inhibitor, FSG67. Additionally, the functional characteristics of GPATs and the relation between three isoforms (GPAT1, 3, and 4) and insulin resistance has been described in this review.
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19
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AIDA Selectively Mediates Downregulation of Fat Synthesis Enzymes by ERAD to Retard Intestinal Fat Absorption and Prevent Obesity. Cell Metab 2018; 27:843-853.e6. [PMID: 29617643 DOI: 10.1016/j.cmet.2018.02.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 11/05/2017] [Accepted: 02/21/2018] [Indexed: 01/24/2023]
Abstract
The efficiency of intestinal absorption of dietary fat constitutes a primary determinant accounting for individual vulnerability to obesity. However, how fat absorption is controlled and contributes to obesity remains unclear. Here, we show that inhibition of endoplasmic-reticulum-associated degradation (ERAD) increases the abundance of triacylglycerol synthesis enzymes and fat absorption in small intestine. The C2-domain protein AIDA acts as an essential factor for the E3-ligase HRD1 of ERAD to downregulate rate-limiting acyltransferases GPAT3, MOGAT2, and DGAT2. Aida-/- mice, when grown in a thermal-neutral condition or fed high-fat diet, display increased intestinal fatty acid re-esterification, circulating and tissue triacylglycerol, accompanied with severely increased adiposity without enhancement of adipogenesis. Intestine-specific knockout of Aida largely phenocopies its whole-body knockout, strongly indicating that increased intestinal TAG synthesis is a primary impetus to obesity. The AIDA-mediated ERAD system may thus represent an anti-thrifty mechanism impinging on the enzymes for intestinal fat absorption and systemic fat storage.
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20
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Xiao C, Stahel P, Carreiro AL, Buhman KK, Lewis GF. Recent Advances in Triacylglycerol Mobilization by the Gut. Trends Endocrinol Metab 2018; 29:151-163. [PMID: 29306629 DOI: 10.1016/j.tem.2017.12.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/26/2022]
Abstract
Dietary lipid absorption and lipoprotein secretion by the gut are important in maintaining whole-body energy homeostasis and have significant implications for health and disease. The processing of dietary lipids, including storage within and subsequent mobilization and transport from enterocyte cytoplasmic lipid droplets or other intestinal lipid storage pools (including the secretary pathway, lamina propria and lymphatics) and secretion of chylomicrons, involves coordinated steps that are subject to various controls. This review summarizes recent advances in our understanding of the mechanisms that underlie lipid storage and mobilization by small intestinal enterocytes and the intestinal lymphatic vasculature. Therapeutic targeting of lipid processing by the gut may provide opportunities for the treatment and prevention of dyslipidemia, and for improving health status.
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Affiliation(s)
- Changting Xiao
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Priska Stahel
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada
| | - Alicia L Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Gary F Lewis
- Departments of Medicine and Physiology, Division of Endocrinology and Metabolism, Banting and Best Diabetes Centre, University of Toronto, Toronto, ON, Canada.
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21
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Zhang P, Reue K. Lipin proteins and glycerolipid metabolism: Roles at the ER membrane and beyond. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:1583-1595. [PMID: 28411173 PMCID: PMC5688847 DOI: 10.1016/j.bbamem.2017.04.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/29/2017] [Accepted: 04/09/2017] [Indexed: 01/09/2023]
Abstract
The regulation of glycerolipid biosynthesis is critical for homeostasis of cellular lipid stores and membranes. Here we review the role of lipin phosphatidic acid phosphatase enzymes in glycerolipid synthesis. Lipin proteins are unique among glycerolipid biosynthetic enzymes in their ability to transit among cellular membranes, rather than remain membrane tethered. We focus on the mechanisms that underlie lipin protein interactions with membranes and the versatile roles of lipins in several organelles, including the endoplasmic reticulum, mitochondria, endolysosomes, lipid droplets, and nucleus. We also review the corresponding physiological roles of lipins, which have been uncovered by the study of genetic lipin deficiencies. We propose that the growing body of knowledge concerning the biochemical and cellular activities of lipin proteins will be valuable for understanding the physiological functions of lipin proteins in health and disease. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Peixiang Zhang
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States
| | - Karen Reue
- Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, United States; Molecular Biology Institute, University of California, Los Angeles, United States.
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22
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Paalvast Y, de Boer JF, Groen AK. Developments in intestinal cholesterol transport and triglyceride absorption. Curr Opin Lipidol 2017; 28:248-254. [PMID: 28338522 DOI: 10.1097/mol.0000000000000415] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW To discuss recent advances in research focused on intestinal lipid handling. RECENT FINDINGS An important strategy in reducing atherosclerosis and risk of cardiovascular events is to increase the rate of reverse cholesterol transport, including its final step; cholesterol excretion from the body. The rate of removal is determined by a complex interplay between the factors involved in regulation of intestinal cholesterol absorption. One of these factors is a process known as transintestinal cholesterol excretion. This pathway comprises transport of cholesterol directly from the blood, through the enterocyte, into the intestinal lumen. In humans, this pathway accounts for 35% of cholesterol excretion in the feces. Mechanistic studies in mice revealed that, activation of the bile acid receptor farnesoid X receptor increases cholesterol removal via the transintestinal cholesterol excretion pathway as well as decreases plasma cholesterol and triglyceride providing an interesting target for treatment of dyslipidemia in humans. The physical chemical properties of bile acids are under control of farnesoid X receptor and determine intestinal cholesterol and triglyceride solubilization as well as absorption, providing a direct link between these two important factors in the pathogenesis of cardiovascular disease. Besides bile acids, intestinal phospholipids are important for luminal lipid solubilization. Interestingly, phospholipid remodeling through LPCAT3 was shown to be pivotal for uptake of fatty acids by enterocytes, which may provide a mechanistic handle for therapeutic intervention. SUMMARY The importance of the intestine in control of cholesterol and triglyceride homeostasis is increasingly recognized. Recently, novel factors involved in regulation of cholesterol excretion and intestinal triglyceride and fatty acid uptake have been reported and are discussed in this short review.
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Affiliation(s)
- Yared Paalvast
- aDepartment of Pediatrics bDepartment of Laboratory Medicine, University of Groningen, University Medical Center Groningen cDepartment of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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23
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Maguire M, Bushkofsky JR, Larsen MC, Foong YH, Tanumihardjo SA, Jefcoate CR. Diet-dependent retinoid effects on liver gene expression include stellate and inflammation markers and parallel effects of the nuclear repressor Shp. J Nutr Biochem 2017; 47:63-74. [PMID: 28570941 DOI: 10.1016/j.jnutbio.2017.04.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/24/2017] [Accepted: 04/12/2017] [Indexed: 02/06/2023]
Abstract
For mice, a maternal vitamin A (VA)-deficient diet initiated from midgestation (GVAD) produces serum retinol deficiency in mature offspring. We hypothesize that the effects of GVAD arise from preweaning developmental changes. We compare the effect of this GVAD protocol in combination with a postweaning high-fat diet (HFD) or high-carbohydrate diet (LF12). Each is compared to an equivalent VA-sufficient combination. GVAD extensively decreased serum retinol and liver retinol, retinyl esters, and retinoid homeostasis genes (Lrat, Cyp26b1 and Cyp26a1). These suppressions were each more effective with LF12 than with HFD. Postweaning initiation of VA deficiency with LF12 depleted liver retinoids, but serum retinol was unaffected. Liver retinoid depletion, therefore, precedes serum attenuation. Maternal LF12 decreased the obesity response to the HFD, which was further decreased by GVAD. LF12 fed to the mother and offspring extensively stimulated genes marking stellate activation (Col1a1, Timp2 and Cyp1b1) and novel inflammation markers (Ly6d, Trem2 and Nupr1). The GVAD with LF12 diet combination suppressed these responses. GVAD in combination with the HFD increased these same clusters. A further set of expression differences on the HFD when compared to a high-carbohydrate diet was prevented when GVAD was combined with HFD. Most of these GVAD gene changes match published effects from deletion of Nr0b2/Shp, a retinoid-responsive, nuclear co-repressor that modulates metabolic homeostasis. The stellate and inflammatory increases seen with the high-carbohydrate LF12 diet may represent postprandial responses. They depend on retinol and Shp, but the regulation reverses with an HFD.
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Affiliation(s)
- Meghan Maguire
- Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI 53705; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705
| | - Justin R Bushkofsky
- Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI 53705
| | | | - Yee Hoon Foong
- Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI 53705
| | - Sherry A Tanumihardjo
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI 53705
| | - Colin R Jefcoate
- Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI 53705; Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI 53705.
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D'Aquila T, Hung YH, Carreiro A, Buhman KK. Recent discoveries on absorption of dietary fat: Presence, synthesis, and metabolism of cytoplasmic lipid droplets within enterocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:730-47. [PMID: 27108063 DOI: 10.1016/j.bbalip.2016.04.012] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 03/16/2016] [Accepted: 04/16/2016] [Indexed: 02/07/2023]
Abstract
Dietary fat provides essential nutrients, contributes to energy balance, and regulates blood lipid concentrations. These functions are important to health, but can also become dysregulated and contribute to diseases such as obesity, diabetes, cardiovascular disease, and cancer. Within enterocytes, the digestive products of dietary fat are re-synthesized into triacylglycerol, which is either secreted on chylomicrons or stored within cytoplasmic lipid droplets (CLDs). CLDs were originally thought to be inert stores of neutral lipids, but are now recognized as dynamic organelles that function in multiple cellular processes in addition to lipid metabolism. This review will highlight recent discoveries related to dietary fat absorption with an emphasis on the presence, synthesis, and metabolism of CLDs within this process.
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Affiliation(s)
- Theresa D'Aquila
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Alicia Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.
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