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Yao W, Wang T, Huang L, Bao Z, Wen S, Huang F. Embelin alleviates weaned piglets intestinal inflammation and barrier dysfunction via PCAF/NF-κB signaling pathway in intestinal epithelial cells. J Anim Sci Biotechnol 2022; 13:139. [PMID: 36514139 DOI: 10.1186/s40104-022-00787-z] [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: 05/10/2022] [Accepted: 10/03/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Intestinal barrier plays key roles in maintaining intestinal homeostasis. Inflammation damage can severely destroy the intestinal integrity of mammals. This study was conducted to investigate the protective effects of embelin and its molecular mechanisms on intestinal inflammation in a porcine model. One hundred sixty 21-day-old castrated weaned pigs (Duroc × Landrace × Yorkshire, average initial body weight was 7.05 ± 0.28 kg, equal numbers of castrated males and females) were allotted to four groups and fed with a basal diet or a basal diet containing 200, 400, or 600 mg embelin/kg for 28 d. The growth performance, intestinal inflammatory cytokines, morphology of jejunum and ileum, tight junctions in the intestinal mucosa of piglets were tested. IPEC-1 cells with overexpression of P300/CBP associating factor (PCAF) were treated with embelin, the activity of PCAF and acetylation of nuclear factor-κB (NF-κB) were analyzed to determine the effect of embelin on PCAF/NF-κB pathway in vitro. RESULTS The results showed that embelin decreased (P < 0.05) serum D-lactate and diamine oxidase (DAO) levels, and enhanced the expression of ZO-1, occludin and claudin-1 protein in jejunum and ileum. Moreover, the expression levels of critical inflammation molecules (interleukin-1β, interleukin-6, tumor necrosis factor-α, and NF-κB) were down-regulated (P < 0.05) by embelin in jejunal and ileal mucosa. Meanwhile, the activity of PCAF were down-regulated (P < 0.05) by embelin. Importantly, transfection of PCAF siRNAs to IPEC-1 cell decreased NF-κB activities; embelin treatment downregulated (P < 0.05) the acetylation and activities of NF-κB by 31.7%-74.6% in IPEC-1 cells with overexpression of PCAF. CONCLUSIONS These results suggested that embelin ameliorates intestinal inflammation in weaned pigs, which might be mediated by suppressing the PCAF/NF-κB signaling pathway.
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Affiliation(s)
- Weilei Yao
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Tongxin Wang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lu Huang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhengxi Bao
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shu Wen
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Feiruo Huang
- Department of Animal Nutrition and Feed Science, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
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2
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Cao YG, Bae S, Villarreal J, Moy M, Chun E, Michaud M, Lang JK, Glickman JN, Lobel L, Garrett WS. Faecalibaculum rodentium remodels retinoic acid signaling to govern eosinophil-dependent intestinal epithelial homeostasis. Cell Host Microbe 2022; 30:1295-1310.e8. [PMID: 35985335 PMCID: PMC9481734 DOI: 10.1016/j.chom.2022.07.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/20/2022] [Accepted: 07/21/2022] [Indexed: 12/19/2022]
Abstract
The intestinal epithelium plays critical roles in sensing and integrating dietary and microbial signals. How microbiota and intestinal epithelial cell (IEC) interactions regulate host physiology in the proximal small intestine, particularly the duodenum, is unclear. Using single-cell RNA sequencing of duodenal IECs under germ-free (GF) and different conventional microbiota compositions, we show that specific microbiota members alter epithelial homeostasis by increasing epithelial turnover rate, crypt proliferation, and major histocompatibility complex class II (MHCII) expression. Microbiome profiling identified Faecalibaculum rodentium as a key species involved in this regulation. F. rodentium decreases enterocyte expression of retinoic-acid-producing enzymes Adh1, Aldh1a1, and Rdh7, reducing retinoic acid signaling required to maintain certain intestinal eosinophil populations. Eosinophils suppress intraepithelial-lymphocyte-mediated production of interferon-γ that regulates epithelial cell function. Thus, we identify a retinoic acid-eosinophil-interferon-γ-dependent circuit by which the microbiota modulates duodenal epithelial homeostasis.
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Affiliation(s)
- Y Grace Cao
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Sena Bae
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Jannely Villarreal
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Madelyn Moy
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Eunyoung Chun
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Monia Michaud
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Jessica K Lang
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Jonathan N Glickman
- Beth Israel Deaconess Medical Center, Boston, MA 02115, USA; Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
| | - Lior Lobel
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA
| | - Wendy S Garrett
- Departments of Immunology & Infectious Diseases and Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Harvard T.H. Chan Microbiome in Public Health Center, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
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3
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Silverman RB. Inactivators of Ornithine Aminotransferase for the Treatment of Hepatocellular Carcinoma. ACS Med Chem Lett 2021; 13:38-49. [PMID: 35059122 PMCID: PMC8762738 DOI: 10.1021/acsmedchemlett.1c00526] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/22/2021] [Indexed: 01/16/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is the second or third leading cause of cancer mortality worldwide (depending on which statistics are used), yet there is no effective treatment. Currently, there are nine FDA-approved drugs for HCC, five monoclonal antibodies and four tyrosine kinase inhibitors. Ornithine aminotransferase (OAT) has been validated as a target in preclinical studies, which demonstrates that it is a potential target to treat HCC. Currently, there are no OAT inactivators in clinical trials for HCC. This Innovation describes evidence to support inhibition of OAT as a novel approach for HCC tumor growth inhibition. After the mechanism of OAT is discussed, the origins of our involvement in OAT inactivation, based on our previous work on mechanism-based inactivation of GABA-AT, are described. Once it was demonstrated that OAT inactivation does lead to HCC tumor growth inhibition, new selective OAT inactivators were designed and their inactivation mechanisms were elucidated. A summary of these mechanistic studies is presented. Inactivators of OAT provide the potential for treatment of HCC, targeting the Wnt/β-catenin pathway.
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Ginguay A, Cynober L, Curis E, Nicolis I. Ornithine Aminotransferase, an Important Glutamate-Metabolizing Enzyme at the Crossroads of Multiple Metabolic Pathways. BIOLOGY 2017; 6:biology6010018. [PMID: 28272331 PMCID: PMC5372011 DOI: 10.3390/biology6010018] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 02/06/2023]
Abstract
Ornithine δ-aminotransferase (OAT, E.C. 2.6.1.13) catalyzes the transfer of the δ-amino group from ornithine (Orn) to α-ketoglutarate (aKG), yielding glutamate-5-semialdehyde and glutamate (Glu), and vice versa. In mammals, OAT is a mitochondrial enzyme, mainly located in the liver, intestine, brain, and kidney. In general, OAT serves to form glutamate from ornithine, with the notable exception of the intestine, where citrulline (Cit) or arginine (Arg) are end products. Its main function is to control the production of signaling molecules and mediators, such as Glu itself, Cit, GABA, and aliphatic polyamines. It is also involved in proline (Pro) synthesis. Deficiency in OAT causes gyrate atrophy, a rare but serious inherited disease, a further measure of the importance of this enzyme.
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Affiliation(s)
- Antonin Ginguay
- Clinical Chemistry, Cochin Hospital, GH HUPC, AP-HP, 75014 Paris, France.
- Laboratory of Biological Nutrition, EA 4466 PRETRAM, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
| | - Luc Cynober
- Clinical Chemistry, Cochin Hospital, GH HUPC, AP-HP, 75014 Paris, France.
- Laboratory of Biological Nutrition, EA 4466 PRETRAM, Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
| | - Emmanuel Curis
- Laboratoire de biomathématiques, plateau iB², Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
- UMR 1144, INSERM, Université Paris Descartes, 75006 Paris, France.
- UMR 1144, Université Paris Descartes, 75006 Paris, France.
- Service de biostatistiques et d'informatique médicales, hôpital Saint-Louis, Assistance publique-hôpitaux de Paris, 75010 Paris, France.
| | - Ioannis Nicolis
- Laboratoire de biomathématiques, plateau iB², Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
- EA 4064 "Épidémiologie environnementale: Impact sanitaire des pollutions", Faculté de Pharmacie, Université Paris Descartes, 75006 Paris, France.
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5
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Kong X, Wang X, Yin Y, Li X, Gao H, Bazer FW, Wu G. Putrescine stimulates the mTOR signaling pathway and protein synthesis in porcine trophectoderm cells. Biol Reprod 2014; 91:106. [PMID: 25253735 DOI: 10.1095/biolreprod.113.113977] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Insufficient placental growth is a major factor contributing to intrauterine growth retardation in mammals. There is growing evidence that putrescine produced from arginine (Arg) and proline via ornithine decarboxylase is a key regulator of angiogenesis, embryogenesis, as well as placental and fetal growth. However, the underlying mechanisms are largely unknown. The present study tested the hypothesis that putrescine stimulates protein synthesis by activating the mechanistic target of rapamycin (mTOR) signaling pathway in porcine trophectoderm cell line 2 cells. The cells were cultured for 2 to 4 days in customized Arg-free Dulbecco modified Eagle Ham medium containing 0, 10, 25, or 50 μM putrescine or 100 μM Arg. Cell proliferation, protein synthesis, and degradation, as well as the abundance of total and phosphorylated mTOR, ribosomal protein S6 kinase 1, and eukaryotic initiation factor 4E-binding protein-1 (4EBP1), were determined. Our results indicate that putrescine promotes cell proliferation and protein synthesis in a dose- and time-dependent manner, which was inhibited by difluoro-methylornithine (an inhibitor of ornithine decarboxylase). Moreover, supplementation of culture medium with putrescine increased the abundance of phosphorylated mTOR and its downstream targets, 4EBP1 and p70 S6K1 proteins. Collectively, these findings reveal a novel and important role for putrescine in regulating the mTOR signaling pathway in porcine placental cells. We suggest that dietary supplementation with or intravenous administration of putrescine may provide a new and effective strategy to improve survival and growth of embryos/fetuses in mammals.
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Affiliation(s)
- Xiangfeng Kong
- Department of Animal Science, Texas A&M University, College Station, Texas Hunan Provincial Engineering Research Center of Healthy Livestock and Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Xiaoqiu Wang
- Department of Animal Science, Texas A&M University, College Station, Texas
| | - Yulong Yin
- Hunan Provincial Engineering Research Center of Healthy Livestock and Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Xilong Li
- Department of Animal Science, Texas A&M University, College Station, Texas
| | - Haijun Gao
- Department of Animal Science, Texas A&M University, College Station, Texas
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University, College Station, Texas
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, Texas State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
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6
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Selicharová I, Kořínek M, Demianová Z, Chrudinová M, Mládková J, Jiráček J. Effects of hyperhomocysteinemia and betaine–homocysteine S-methyltransferase inhibition on hepatocyte metabolites and the proteome. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1596-606. [DOI: 10.1016/j.bbapap.2013.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/30/2013] [Accepted: 05/10/2013] [Indexed: 12/11/2022]
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7
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Xi P, Jiang Z, Dai Z, Li X, Yao K, Zheng C, Lin Y, Wang J, Wu G. Regulation of protein turnover by l-glutamine in porcine intestinal epithelial cells. J Nutr Biochem 2012; 23:1012-7. [DOI: 10.1016/j.jnutbio.2011.05.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 05/15/2011] [Accepted: 05/19/2011] [Indexed: 01/28/2023]
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8
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Mandal TK, Parvin N, Mondal S, Saxena V, Saxena AK, Sarkar S, Saha M. Relation of soya bean meal level to the concentration of plasma free amino acids and body growth in white rats. J Anim Physiol Anim Nutr (Berl) 2012; 96:191-7. [PMID: 21429046 DOI: 10.1111/j.1439-0396.2011.01136.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Amino acid (AA) levels in plasma and body growth were determined in rats (n20) fed diets with different soya bean meal levels. Free AA in plasma was determined by reversed-phase high-pressure liquid chromatography. We have used four levels of protein diets like 8%, 15%, 23% and 35% in this trial. Rats which were fed the low-protein (8%) diet with low percentage of soya bean meal were found to be growth-retarded. The body weight gain of high protein group (35%) was lower than that of the 23% groups. In the rats fed with the low-soya bean meal diet, some nonessential AA (NEAA) in plasma like asparagine, aspartic acid, cysteine, glutamic acid and serine increased, whereas the essential AA (EAA), with the exception of arginine, methionine and valine decreased. Here, plasma EAA-to-NEAA ratios were not correlated to growth and experimental diet. We hypothesize that AA metabolism is associated to changes in growth in rats on different protein intake. This study has showed the sensitivity of body mass gain, feed intake, feed conversion rate of rats to four levels of protein in the diet under controlled experimental conditions.
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Affiliation(s)
- Tapas K Mandal
- D.A.-V.P.G. College, Department of Zoology, CSJM University, Kanpur, India.
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9
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Kong X, Tan B, Yin Y, Gao H, Li X, Jaeger LA, Bazer FW, Wu G. L-Arginine stimulates the mTOR signaling pathway and protein synthesis in porcine trophectoderm cells. J Nutr Biochem 2011; 23:1178-83. [PMID: 22137265 DOI: 10.1016/j.jnutbio.2011.06.012] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 06/01/2011] [Accepted: 06/29/2011] [Indexed: 11/24/2022]
Abstract
Impairment of placental growth is a major factor contributing to intrauterine growth retardation (IUGR) in both human pregnancy and animal production. Results of recent studies indicate that administration of L-arginine (Arg) to gestating pigs or sheep with IUGR fetuses can enhance fetal growth. However, the underlying mechanisms are largely unknown. The present study tested the hypothesis that Arg stimulates the mammalian target of rapamycin (mTOR) signaling pathway and protein synthesis in porcine conceptus trophectoderm (pTr2) cells. The cells were cultured for 4 days in Arg-free Dulbecco's modified Eagle's Ham medium containing 10, 50, 100, 200, 350 or 500 μM Arg. Cell numbers, protein synthesis and degradation, as well as total and phosphorylated levels of mTOR, ribosomal protein S6 kinase 1 (p70S6K) and eukaryotic initiation factor 4E-binding protein-1 (4EBP1), were determined. The pTr2 cells exhibited time (0-6 days)- and Arg concentration (10-350 μM)-dependent increases in proliferation. Addition of 100 and 350 μM Arg to culture medium dose-dependently increased (a) protein synthesis and decreased protein degradation and (b) the abundance of total and phosphorylated mTOR, p70S6K and 4EBP1 proteins. Effects of 350 μM Arg on intracellular protein turnover were only modestly affected when nitric oxide synthesis was inhibited. Collectively, these results indicate a novel and important role for Arg in promoting growth of porcine placental cells largely via a nitric-oxide-independent pathway. Additionally, these findings help to explain beneficial effects of Arg supplementation on improving survival and growth of embryos/fetuses in mammals.
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Affiliation(s)
- Xiangfeng Kong
- Research Center for Healthy Breeding of Livestock and Poultry and Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, 410125 Hunan, China
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10
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Alpha-ketoglutarate inhibits glutamine degradation and enhances protein synthesis in intestinal porcine epithelial cells. Amino Acids 2011; 42:2491-500. [DOI: 10.1007/s00726-011-1060-6] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 08/09/2011] [Indexed: 12/14/2022]
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11
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Humann FC, Hartfelder K. Representational Difference Analysis (RDA) reveals differential expression of conserved as well as novel genes during caste-specific development of the honey bee (Apis mellifera L.) ovary. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 41:602-612. [PMID: 21477651 DOI: 10.1016/j.ibmb.2011.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/18/2011] [Accepted: 03/29/2011] [Indexed: 05/28/2023]
Abstract
In highly eusocial insects, such as the honey bee, Apis mellifera, the reproductive bias has become embedded in morphological caste differences. These are most expressively denoted in ovary size, with adult queens having large ovaries consisting of 150-200 ovarioles each, while workers typically have only 1-20 ovarioles per ovary. This morphological differentiation is a result of hormonal signals triggered by the diet change in the third larval instar, which eventually generate caste-specific gene expression patterns. To reveal these we produced differential gene expression libraries by Representational Difference Analysis (RDA) for queen and worker ovaries in a developmental stage when cell death is a prominent feature in the ovarioles of workers, whereas all ovarioles are maintained and extend in length in queens. In the queen library, 48% of the gene set represented homologs of known Drosophila genes, whereas in the worker ovary, the largest set (59%) were ESTs evidencing novel genes, not even computationally predicted in the honey bee genome. Differential expression was confirmed by quantitative RT-PCR for a selected gene set, denoting major differences for two queen and two worker library genes. These included two unpredicted genes located in chromosome 11 (Group11.35 and Group11.31, respectively) possibly representing long non-coding RNAs. Being candidates as modulators of ovary development, their expression and functional analysis should be a focal point for future studies.
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Affiliation(s)
- Fernanda C Humann
- Departamento de Biologia Celular e Molecular e de Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil.
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12
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Geng M, Li T, Kong X, Song X, Chu W, Huang R, Yin Y, Wu G. Reduced expression of intestinal N-acetylglutamate synthase in suckling piglets: a novel molecular mechanism for arginine as a nutritionally essential amino acid for neonates. Amino Acids 2010; 40:1513-22. [DOI: 10.1007/s00726-010-0761-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 09/23/2010] [Indexed: 10/19/2022]
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13
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Jortzik E, Fritz-Wolf K, Sturm N, Hipp M, Rahlfs S, Becker K. Redox regulation of Plasmodium falciparum ornithine δ-aminotransferase. J Mol Biol 2010; 402:445-59. [PMID: 20673832 DOI: 10.1016/j.jmb.2010.07.039] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 07/16/2010] [Accepted: 07/20/2010] [Indexed: 11/16/2022]
Abstract
Ornithine δ-aminotransferase (OAT) of the malaria parasite Plasmodium falciparum catalyzes the reversible conversion of ornithine into glutamate-5-semialdehyde and glutamate and is-in contrast to its human counterpart-activated by thioredoxin (Trx) by a factor of 10. Trx, glutaredoxin, and plasmoredoxin are redox-active proteins that play a crucial role in the maintenance and control of redox reactions, and were shown to interact with P. falciparum OAT. OAT, which is involved in ornithine homeostasis and proline biosynthesis, is essential for mitotic cell division in rapidly growing cells, thus representing a potential target for chemotherapeutic intervention. Here we report the three-dimensional crystal structure of P. falciparum OAT at 2.3 Å resolution. The overall structure is very similar to that of the human OAT. However, in plasmodial OAT, the loop involved in substrate binding contains two cysteine residues, which are lacking in human OAT. Site-directed mutagenesis of these cysteines and functional analysis demonstrated that Cys154 and Cys163 mediate the interaction with Trx. Interestingly, the Cys154→Ser mutant has a strongly reduced specific activity, most likely due to impaired binding of ornithine. Cys154 and Cys163 are highly conserved in Plasmodium but do not exist in other organisms, suggesting that redox regulation of OAT by Trx is specific for malaria parasites. Plasmodium might require a tight Trx-mediated control of OAT activity for coordinating ornithine homeostasis, polyamine synthesis, proline synthesis, and mitotic cell division.
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Affiliation(s)
- Esther Jortzik
- Interdisciplinary Research Center, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany
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14
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Tan B, Yin Y, Kong X, Li P, Li X, Gao H, Li X, Huang R, Wu G. L-Arginine stimulates proliferation and prevents endotoxin-induced death of intestinal cells. Amino Acids 2010; 38:1227-35. [PMID: 19669080 PMCID: PMC2850530 DOI: 10.1007/s00726-009-0334-8] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 07/22/2009] [Indexed: 12/18/2022]
Abstract
This study tested the hypothesis that L-arginine (Arg) may stimulate cell proliferation and prevent lipopolysaccharide (LPS)-induced death of intestinal cells. Intestinal porcine epithelial cells (IPEC-1) were cultured for 4 days in Arg-free Dulbecco's modified Eagle's-F12 Ham medium (DMEM-F12) containing 10, 100 or 350 microM Arg and 0 or 20 ng/ml LPS. Cell numbers, protein concentrations, protein synthesis and degradation, as well as mammalian target of rapamycin (mTOR) and Toll-like receptor 4 (TLR4) signaling pathways were determined. Without LPS, IPEC-1 cells exhibited time- and Arg-dependent growth curves. LPS treatment increased cell death and reduced protein concentrations in IPEC-1 cells. Addition of 100 and 350 microM Arg to culture medium dose-dependently attenuated LPS-induced cell death and reduction of protein concentrations, in comparison with the basal medium containing 10 microM Arg. Furthermore, supplementation of 100 and 350 microM Arg increased protein synthesis and reduced protein degradation in both control and LPS-treated IPEC-1 cells. Consistent with the data on cell growth and protein turnover, addition of 100 or 350 microM Arg to culture medium increased relative protein levels for phosphorylated mTOR and phosphorylated ribosomal protein S6 kinase-1, while reducing the relative levels of TLR4 and phosphorylated levels of nuclear factor-kappaB in LPS-treated IPEC-1 cells. These results demonstrate a protective effect of Arg against LPS-induced enterocyte damage through mechanisms involving mTOR and TLR4 signaling pathways, as well as intracellular protein turnover.
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Affiliation(s)
- Bie Tan
- Hunan Engineering Technology Research Center of Healthy Animal Husbandry and Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, 410125 Hunan, China
- Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
- The Graduate School of the Chinese Academy of Sciences, 100039 Beijing, China
| | - Yulong Yin
- Hunan Engineering Technology Research Center of Healthy Animal Husbandry and Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, 410125 Hunan, China
| | - Xiangfeng Kong
- Hunan Engineering Technology Research Center of Healthy Animal Husbandry and Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, 410125 Hunan, China
- Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
| | - Peng Li
- Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
| | - Xilong Li
- Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
| | - Haijun Gao
- Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
| | - Xinguo Li
- Hunan Institute of Animal Husbandry and Veterinary Medicine, Changsha, 410131 Hunan, China
| | - Ruilin Huang
- Hunan Engineering Technology Research Center of Healthy Animal Husbandry and Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, 410125 Hunan, China
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
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Fu WJ, Stromberg AJ, Viele K, Carroll RJ, Wu G. Statistics and bioinformatics in nutritional sciences: analysis of complex data in the era of systems biology. J Nutr Biochem 2010; 21:561-72. [PMID: 20233650 DOI: 10.1016/j.jnutbio.2009.11.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 11/10/2009] [Accepted: 11/12/2009] [Indexed: 10/19/2022]
Abstract
Over the past 2 decades, there have been revolutionary developments in life science technologies characterized by high throughput, high efficiency, and rapid computation. Nutritionists now have the advanced methodologies for the analysis of DNA, RNA, protein, low-molecular-weight metabolites, as well as access to bioinformatics databases. Statistics, which can be defined as the process of making scientific inferences from data that contain variability, has historically played an integral role in advancing nutritional sciences. Currently, in the era of systems biology, statistics has become an increasingly important tool to quantitatively analyze information about biological macromolecules. This article describes general terms used in statistical analysis of large, complex experimental data. These terms include experimental design, power analysis, sample size calculation, and experimental errors (Type I and II errors) for nutritional studies at population, tissue, cellular, and molecular levels. In addition, we highlighted various sources of experimental variations in studies involving microarray gene expression, real-time polymerase chain reaction, proteomics, and other bioinformatics technologies. Moreover, we provided guidelines for nutritionists and other biomedical scientists to plan and conduct studies and to analyze the complex data. Appropriate statistical analyses are expected to make an important contribution to solving major nutrition-associated problems in humans and animals (including obesity, diabetes, cardiovascular disease, cancer, ageing, and intrauterine growth retardation).
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Affiliation(s)
- Wenjiang J Fu
- Department of Epidemiology, Michigan State University, East Lansing, MI 48824, USA
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Amino acids: metabolism, functions, and nutrition. Amino Acids 2009; 37:1-17. [PMID: 19301095 DOI: 10.1007/s00726-009-0269-0] [Citation(s) in RCA: 1603] [Impact Index Per Article: 106.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Accepted: 03/01/2009] [Indexed: 02/06/2023]
Abstract
Recent years have witnessed the discovery that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. Additionally, AA are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of AA and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the functions. However, elevated levels of AA and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among AA in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional AA, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these AA may be beneficial for (1) ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaning-associated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility); (2) optimizing efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, AA have important functions in both nutrition and health.
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Chen L, Li P, Wang J, Li X, Gao H, Yin Y, Hou Y, Wu G. Catabolism of nutritionally essential amino acids in developing porcine enterocytes. Amino Acids 2009; 37:143-52. [DOI: 10.1007/s00726-009-0268-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 02/23/2009] [Indexed: 12/14/2022]
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High fat feeding and dietary L-arginine supplementation differentially regulate gene expression in rat white adipose tissue. Amino Acids 2009; 37:187-98. [PMID: 19212806 DOI: 10.1007/s00726-009-0246-7] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Accepted: 01/20/2009] [Indexed: 12/17/2022]
Abstract
Dietary L-arginine (Arg) supplementation reduces white-fat gain in diet-induced obese rats but the underlying mechanisms are unknown. This study tested the hypothesis that Arg treatment affects expression of genes related to lipid metabolism in adipose tissue. Four-week-old male Sprague-Dawley rats were fed a low-fat (LF) or high-fat (HF) diet for 15 weeks. Thereafter, lean or obese rats continued to be fed their same respective diets and received drinking water containing 1.51% Arg-HCl or 2.55% L: -alanine (isonitrogenous control). After 12 weeks of Arg supplementation, rats were euthanized to obtain retroperitoneal adipose tissue for analyzing global changes in gene expression by microarray. The results were confirmed by RT-PCR analysis. HF feeding decreased mRNA levels for lipogenic enzymes, AMP-activated protein kinase, glucose transporters, heme oxygenase 3, glutathione synthetase, superoxide dismutase 3, peroxiredoxin 5, glutathione peroxidase 3, and stress-induced protein, while increasing expression of carboxypeptidase-A, peroxisome proliferator activated receptor (PPAR)-alpha, caspase 2, caveolin 3, and diacylglycerol kinase. In contrast, Arg supplementation reduced mRNA levels for fatty acid binding protein 1, glycogenin, protein phosphates 1B, caspases 1 and 2, and hepatic lipase, but increased expression of PPARgamma, heme oxygenase 3, glutathione synthetase, insulin-like growth factor II, sphingosine-1-phosphate receptor, and stress-induced protein. Biochemical analysis revealed oxidative stress in white adipose tissue of HF-fed rats, which was prevented by Arg supplementation. Collectively, these results indicate that HF diet and Arg supplementation differentially regulate gene expression to affect energy-substrate oxidation, redox state, fat accretion, and adipocyte differentiation in adipose tissue. Our findings provide a molecular mechanism to explain a beneficial effect of Arg on ameliorating diet-induced obesity in mammals.
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L-Glutamine or L-alanyl-L-glutamine prevents oxidant- or endotoxin-induced death of neonatal enterocytes. Amino Acids 2009; 37:131-42. [PMID: 19189199 DOI: 10.1007/s00726-009-0243-x] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 01/14/2009] [Indexed: 02/08/2023]
Abstract
This study tested the hypothesis that L-glutamine (Gln) or L-alanyl-L-glutamine (Ala-Gln) prevents oxidant- or endotoxin-induced death of neonatal enterocytes. Enterocytes of neonatal pigs rapidly hydrolyzed Ala-Gln and utilized Gln. To determine whether Gln or Ala-Gln has a cytoprotective effect, IPEC-1 cells were cultured for 24 h in Gln-free Dulbecco's modified Eagle's-F12 Ham medium containing 0, 0.5, 2.0 or 5.0 mM Gln or Ala-Gln, and 0, 0.5 mM H(2)O(2) or 30 ng/ml lipopolysaccharide (LPS). Without Gln or Ala-Gln, H(2)O(2)- or LPS-treated cells exhibited almost complete death. Gln or Ala-Gln at 0.5, 2 and 5 mM dose-dependently reduced H(2)O(2)- or LPS-induced cell death by 14, 54 and 95%, respectively, whereas D: -glutamine, alanine, glutamate, ornithine, proline, glucosamine or nucleosides had no effect. To evaluate the effectiveness of Gln or Ala-Gln in vivo, 7-day-old piglets received one-week oral administration of Gln or Ala-Gln (3.42 mmol/kg body weight) twice daily and then a single intraperitoneal injection of LPS (0.1 mg/kg body weight); piglets were euthanized in 24 and 48 h to analyze intestinal apoptotic proteins and morphology. Administration of Gln or Ala-Gln to LPS-challenged piglets increased Gln concentrations in small-intestinal lumen and plasma, reduced intestinal expression of Toll-like receptor-4, active caspase-3 and NFkB, ameliorated intestinal injury, decreased rectal temperature, and enhanced growth performance. These results demonstrate a protective effect of Gln or Ala-Gln against H(2)O(2)- or LPS-induced enterocyte death. The findings support addition of Gln or Ala-Gln to current Gln-free pediatric amino acid solutions to prevent intestinal oxidative injury and inflammatory disease in neonates.
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Wu G, Bazer FW, Davis TA, Kim SW, Li P, Marc Rhoads J, Carey Satterfield M, Smith SB, Spencer TE, Yin Y. Arginine metabolism and nutrition in growth, health and disease. Amino Acids 2008; 37:153-68. [PMID: 19030957 DOI: 10.1007/s00726-008-0210-y] [Citation(s) in RCA: 800] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 11/05/2008] [Indexed: 12/11/2022]
Abstract
L-Arginine (Arg) is synthesised from glutamine, glutamate, and proline via the intestinal-renal axis in humans and most other mammals (including pigs, sheep and rats). Arg degradation occurs via multiple pathways that are initiated by arginase, nitric-oxide synthase, Arg:glycine amidinotransferase, and Arg decarboxylase. These pathways produce nitric oxide, polyamines, proline, glutamate, creatine, and agmatine with each having enormous biological importance. Arg is also required for the detoxification of ammonia, which is an extremely toxic substance for the central nervous system. There is compelling evidence that Arg regulates interorgan metabolism of energy substrates and the function of multiple organs. The results of both experimental and clinical studies indicate that Arg is a nutritionally essential amino acid (AA) for spermatogenesis, embryonic survival, fetal and neonatal growth, as well as maintenance of vascular tone and hemodynamics. Moreover, a growing body of evidence clearly indicates that dietary supplementation or intravenous administration of Arg is beneficial in improving reproductive, cardiovascular, pulmonary, renal, gastrointestinal, liver and immune functions, as well as facilitating wound healing, enhancing insulin sensitivity, and maintaining tissue integrity. Additionally, Arg or L-citrulline may provide novel and effective therapies for obesity, diabetes, and the metabolic syndrome. The effect of Arg in treating many developmental and health problems is unique among AAs, and offers great promise for improved health and wellbeing of humans and animals.
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Affiliation(s)
- Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA.
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Wang J, Wu G, Zhou H, Wang F. Emerging technologies for amino acid nutrition research in the post-genome era. Amino Acids 2008; 37:177-86. [DOI: 10.1007/s00726-008-0193-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 10/05/2008] [Indexed: 12/30/2022]
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