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Blaner WS, Brun PJ, Calderon RM, Golczak M. Retinol-binding protein 2 (RBP2): biology and pathobiology. Crit Rev Biochem Mol Biol 2020; 55:197-218. [PMID: 32466661 DOI: 10.1080/10409238.2020.1768207] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Retinol-binding protein 2 (RBP2; originally cellular retinol-binding protein, type II (CRBPII)) is a 16 kDa cytosolic protein that in the adult is localized predominantly to absorptive cells of the proximal small intestine. It is well established that RBP2 plays a central role in facilitating uptake of dietary retinoid, retinoid metabolism in enterocytes, and retinoid actions locally within the intestine. Studies of mice lacking Rbp2 establish that Rbp2 is not required in times of dietary retinoid-sufficiency. However, in times of dietary retinoid-insufficiency, the complete lack of Rbp2 gives rise to perinatal lethality owing to RBP2 absence in both placental (maternal) and neonatal tissues. Moreover, when maintained on a high-fat diet, Rbp2-knockout mice develop obesity, glucose intolerance and a fatty liver. Unexpectedly, recent investigations have demonstrated that RBP2 binds long-chain 2-monoacylglycerols (2-MAGs), including the canonical endocannabinoid 2-arachidonoylglycerol, with very high affinity, equivalent to that of retinol binding. Crystallographic studies establish that 2-MAGs bind to a site within RBP2 that fully overlaps with the retinol binding site. When challenged orally with fat, mucosal levels of 2-MAGs in Rbp2 null mice are significantly greater than those of matched controls establishing that RBP2 is a physiologically relevant MAG-binding protein. The rise in MAG levels is accompanied by elevations in circulating levels of the hormone glucose-dependent insulinotropic polypeptide (GIP). It is not understood how retinoid and/or MAG binding to RBP2 affects the functions of this protein, nor is it presently understood how these contribute to the metabolic and hormonal phenotypes observed for Rbp2-deficient mice.
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Affiliation(s)
- William S Blaner
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Pierre-Jacques Brun
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Rossana M Calderon
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Marcin Golczak
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH, USA
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Xie Y, Wang C, Zhao D, Zhou G, Li C. Processing Method Altered Mouse Intestinal Morphology and Microbial Composition by Affecting Digestion of Meat Proteins. Front Microbiol 2020; 11:511. [PMID: 32322243 PMCID: PMC7156556 DOI: 10.3389/fmicb.2020.00511] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/10/2020] [Indexed: 12/12/2022] Open
Abstract
Our previous study showed that the intake of meat proteins dynamically affected fecal microbial composition. However, the digestion of processed meat proteins in vivo and its relationship with gut microbiota and host remain unclear. In this study, we collected cecal contents and intestinal tissue from the mice fed with casein, soybean protein (SP), and four processed pork proteins for 8 months, and analyzed the amino acid (AA) files, cecum microbial composition and metabolites, and intestinal morphology. Dry-cured pork protein and stewed pork protein (SPP) groups had significantly higher total AA content in gut content than the other groups, but the content of the SPP group was relatively lower in the serum. The microbial composition of the processed meat protein groups differed from the casein or SP group, which is consistent with changes in AA composition. Emulsion sausage protein and SP diets upregulated the microbial AA metabolism, energy metabolism, signaling molecules and interaction, translation, and digestive system function but downregulated the microbial membrane transport, signal transduction and cell motility function compared to the casein diet. The SPP diets increased concentrations of acetate, propionate, butyrate, and isovalerate by specific gut microbes, but it decreased the relative abundance of Akkermansia. Moreover, the mice fed SP diet had relatively lower crypt depth, higher villus height and V/C ratio in duodenum, with the longer small intestines and the heavier cecum than other diets. These results suggested that processing methods altered bioavailability of meat proteins, which affected the intestinal morphology and the cecum microbial composition and function.
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Affiliation(s)
- Yunting Xie
- Key Laboratory of Meat Processing and Quality Control, MOE, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Key Laboratory of Meat Products Processing, MARA, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Chong Wang
- Key Laboratory of Meat Processing and Quality Control, MOE, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Key Laboratory of Meat Products Processing, MARA, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Di Zhao
- Key Laboratory of Meat Processing and Quality Control, MOE, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Key Laboratory of Meat Products Processing, MARA, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Guanghong Zhou
- Key Laboratory of Meat Processing and Quality Control, MOE, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Key Laboratory of Meat Products Processing, MARA, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China
- International Joint Laboratory of Animal Health and Food Safety, MOE, Nanjing Agricultural University, Nanjing, China
| | - Chunbao Li
- Key Laboratory of Meat Processing and Quality Control, MOE, Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, Key Laboratory of Meat Products Processing, MARA, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, China
- International Joint Laboratory of Animal Health and Food Safety, MOE, Nanjing Agricultural University, Nanjing, China
- National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, China
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Li M, Li C, Song S, Zhao F, Xu X, Zhou G. Meat proteins had different effects on oligopeptide transporter PEPT1 in the small intestine of young rats. Int J Food Sci Nutr 2016; 67:995-1004. [PMID: 27455889 DOI: 10.1080/09637486.2016.1210574] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The peptide transporter 1 (PEPT1) in the apical membrane of enterocytes is the central mechanism for regulating the absorption of di- and tripeptides. Dietary proteins may affect PEPT1 abundance and peptide absorption. The present study aimed to characterize changes in PEPT1 mRNA and PEPT1 protein levels in the duodenum and jejunum of young rats after 7-day diet intervention with casein (reference), soy, beef, pork, chicken and fish proteins and further evaluate the impact on the epithelial absorption capacity. RT-PCR and western blot analyses showed that: (1) PEPT1 protein level in duodenum was higher (p < 0.05) for soy protein group than that for casein group. However, no difference was observed in jejunal PEPT1 protein level between any two diet groups (p > 0.05). The soy protein group had lower crypt depth and higher V/C ratio in the jejunum (p < 0.05). (2) PEPT1 mRNA levels were lower (p < 0.05) in rat duodenum and jejunum in pork, chicken and fish protein groups, whose trend was contrary to the results of jejunual histological observation with lower crypt depth, greater villus height and higher V/C ratio. In conclusion, different meat proteins alter distinct PEPT1 expression level and absorption capacity as reflected by gut morphology in small intestine.
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Affiliation(s)
- Mengjie Li
- a Key Laboratory of Meat Processing and Quality Control, MOE , Nanjing Agricultural University , Nanjing , P.R. China ;,b Key Laboratory of Animal Products Processing, MOA , Nanjing Agricultural University , Nanjing , P.R. China ;,c Jiang Collaborative Innovation Center of Meat Production, Processing and Quality Control , Nanjing Agricultural University , Nanjing , P.R. China
| | - Chunbao Li
- a Key Laboratory of Meat Processing and Quality Control, MOE , Nanjing Agricultural University , Nanjing , P.R. China ;,b Key Laboratory of Animal Products Processing, MOA , Nanjing Agricultural University , Nanjing , P.R. China ;,c Jiang Collaborative Innovation Center of Meat Production, Processing and Quality Control , Nanjing Agricultural University , Nanjing , P.R. China
| | - Shangxin Song
- a Key Laboratory of Meat Processing and Quality Control, MOE , Nanjing Agricultural University , Nanjing , P.R. China ;,b Key Laboratory of Animal Products Processing, MOA , Nanjing Agricultural University , Nanjing , P.R. China ;,c Jiang Collaborative Innovation Center of Meat Production, Processing and Quality Control , Nanjing Agricultural University , Nanjing , P.R. China
| | - Fan Zhao
- a Key Laboratory of Meat Processing and Quality Control, MOE , Nanjing Agricultural University , Nanjing , P.R. China ;,b Key Laboratory of Animal Products Processing, MOA , Nanjing Agricultural University , Nanjing , P.R. China ;,c Jiang Collaborative Innovation Center of Meat Production, Processing and Quality Control , Nanjing Agricultural University , Nanjing , P.R. China
| | - Xinglian Xu
- a Key Laboratory of Meat Processing and Quality Control, MOE , Nanjing Agricultural University , Nanjing , P.R. China ;,b Key Laboratory of Animal Products Processing, MOA , Nanjing Agricultural University , Nanjing , P.R. China ;,c Jiang Collaborative Innovation Center of Meat Production, Processing and Quality Control , Nanjing Agricultural University , Nanjing , P.R. China
| | - Guanghong Zhou
- a Key Laboratory of Meat Processing and Quality Control, MOE , Nanjing Agricultural University , Nanjing , P.R. China ;,b Key Laboratory of Animal Products Processing, MOA , Nanjing Agricultural University , Nanjing , P.R. China ;,c Jiang Collaborative Innovation Center of Meat Production, Processing and Quality Control , Nanjing Agricultural University , Nanjing , P.R. China
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Suzuki T, Mochizuki K, Goda T. Localized expression of genes related to carbohydrate and lipid absorption along the crypt-villus axis of rat jejunum. Biochim Biophys Acta Gen Subj 2009; 1790:1624-35. [PMID: 19715743 DOI: 10.1016/j.bbagen.2009.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 08/13/2009] [Accepted: 08/18/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND Enterocytes of the jejunum express several genes related to digestion/absorption of nutrients and ions when these cells rapidly differentiate from crypt to villus cells. However, it is unknown whether the distribution of extensive gene expression along the villus-crypt axis of the jejunum is altered during differentiation. METHODS We investigated the changes in jejunal gene expression during differentiation from crypt to villus cells in rats using DNA microarray analysis on cryostat sections of the villus-crypt columns. RESULTS During differentiation, the expression of many genes related to cell growth rapidly decreased, while expression of genes related to digestion and absorption of nutrients and ions increased. Expression of a subset of genes related to the digestion and absorption of starch and sucrose was highest at the middle of the villi, whereas expression of genes related to dietary fat absorption was highest at the top of the villi. Several transcriptional factors such as Pdx1, Foxa2 and Thra were expressed in the crypt, whereas Klf15 was highly expressed during the crypt-villus transition. Expression of Klf4 and Pparg was highest at the top of the villi. CONCLUSIONS Subsets of genes related to the digestion and absorption of starch/sucrose and dietary fat as well as their transcriptional factors/co-factors are expressed in the specific locations along the crypt-villus axis. GENERAL SIGNIFICANCE The jejunum may absorb nutrients effectively by simultaneously expressing subsets of genes along the villus-crypt axis.
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Affiliation(s)
- Takuji Suzuki
- Laboratory of Nutritional Physiology, The University of Shizuoka Graduate School of Nutritional and Environmental Sciences and Global COE, Shizuoka, Japan
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