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Burckhardt JC, Chong DHY, Pett N, Tropini C. Gut commensal Enterocloster species host inoviruses that are secreted in vitro and in vivo. MICROBIOME 2023; 11:65. [PMID: 36991500 PMCID: PMC10061712 DOI: 10.1186/s40168-023-01496-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 02/17/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND Bacteriophages in the family Inoviridae, or inoviruses, are under-characterized phages previously implicated in bacterial pathogenesis by contributing to biofilm formation, immune evasion, and toxin secretion. Unlike most bacteriophages, inoviruses do not lyse their host cells to release new progeny virions; rather, they encode a secretion system that actively pumps them out of the bacterial cell. To date, no inovirus associated with the human gut microbiome has been isolated or characterized. RESULTS In this study, we utilized in silico, in vitro, and in vivo methods to detect inoviruses in bacterial members of the gut microbiota. By screening a representative genome library of gut commensals, we detected inovirus prophages in Enterocloster spp. (formerly Clostridium spp.). We confirmed the secretion of inovirus particles in in vitro cultures of these organisms using imaging and qPCR. To assess how the gut abiotic environment, bacterial physiology, and inovirus secretion may be linked, we deployed a tripartite in vitro assay that progressively evaluated bacterial growth dynamics, biofilm formation, and inovirus secretion in the presence of changing osmotic environments. Counter to other inovirus-producing bacteria, inovirus production was not correlated with biofilm formation in Enterocloster spp. Instead, the Enterocloster strains had heterogeneous responses to changing osmolality levels relevant to gut physiology. Notably, increasing osmolality induced inovirus secretion in a strain-dependent manner. We confirmed inovirus secretion in a gnotobiotic mouse model inoculated with individual Enterocloster strains in vivo in unperturbed conditions. Furthermore, consistent with our in vitro observations, inovirus secretion was regulated by a changed osmotic environment in the gut due to osmotic laxatives. CONCLUSION In this study, we report on the detection and characterization of novel inoviruses from gut commensals in the Enterocloster genus. Together, our results demonstrate that human gut-associated bacteria can secrete inoviruses and begin to elucidate the environmental niche filled by inoviruses in commensal bacteria. Video Abstract.
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Affiliation(s)
- Juan C Burckhardt
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Derrick H Y Chong
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Nicola Pett
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Carolina Tropini
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.
- School of Biomedical Engineering, University of British Columbia, Vancouver, Canada.
- Humans and the Microbiome Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Canada.
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2
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Mazi TA, Stanhope KL. Erythritol: An In-Depth Discussion of Its Potential to Be a Beneficial Dietary Component. Nutrients 2023; 15:nu15010204. [PMID: 36615861 PMCID: PMC9824470 DOI: 10.3390/nu15010204] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/26/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
The sugar alcohol erythritol is a relatively new food ingredient. It is naturally occurring in plants, however, produced commercially by fermentation. It is also produced endogenously via the pentose phosphate pathway (PPP). Consumers perceive erythritol as less healthy than sweeteners extracted from plants, including sucrose. This review evaluates that perspective by summarizing current literature regarding erythritol's safety, production, metabolism, and health effects. Dietary erythritol is 30% less sweet than sucrose, but contains negligible energy. Because it is almost fully absorbed and excreted in urine, it is better tolerated than other sugar alcohols. Evidence shows erythritol has potential as a beneficial replacement for sugar in healthy and diabetic subjects as it exerts no effects on glucose or insulin and induces gut hormone secretions that modulate satiety to promote weight loss. Long-term rodent studies show erythritol consumption lowers body weight or adiposity. However, observational studies indicate positive association between plasma erythritol and obesity and cardiometabolic disease. It is unlikely that dietary erythritol is mediating these associations, rather they reflect dysregulated PPP due to impaired glycemia or glucose-rich diet. However, long-term clinical trials investigating the effects of chronic erythritol consumption on body weight and risk for metabolic diseases are needed. Current evidence suggests these studies will document beneficial effects of dietary erythritol compared to caloric sugars and allay consumer misperceptions.
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Affiliation(s)
- Tagreed A. Mazi
- Department of Community Health Sciences-Clinical Nutrition, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia
- Department of Nutrition, University of California Davis, 3135 Meyer Hall, One Shields Avenue, Davis, CA 95616, USA
| | - Kimber L. Stanhope
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
- Correspondence: ; Tel.: 530-752-3720
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3
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Glover JS, Browning BD, Ticer TD, Engevik AC, Engevik MA. Acinetobacter calcoaceticus is Well Adapted to Withstand Intestinal Stressors and Modulate the Gut Epithelium. Front Physiol 2022; 13:880024. [PMID: 35685287 PMCID: PMC9170955 DOI: 10.3389/fphys.2022.880024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/12/2022] [Indexed: 12/22/2022] Open
Abstract
Background: The gastrointestinal tract has been speculated to serve as a reservoir for Acinetobacter, however little is known about the ecological fitness of Acinetobacter strains in the gut. Likewise, not much is known about the ability of Acinetobacter to consume dietary, or host derived nutrients or their capacity to modulate host gene expression. Given the increasing prevalence of Acinetobacter in the clinical setting, we sought to characterize how A. calcoaceticus responds to gut-related stressors and identify potential microbe-host interactions. Materials and Methods: To accomplish these aims, we grew clinical isolates and commercially available strains of A. calcoaceticus in minimal media with different levels of pH, osmolarity, ethanol and hydrogen peroxide. Utilization of nutrients was examined using Biolog phenotypic microarrays. To examine the interactions of A. calcoaceticus with the host, inverted murine organoids where the apical membrane is exposed to bacteria, were incubated with live A. calcoaceticus, and gene expression was examined by qPCR. Results: All strains grew modestly at pH 6, 5 and 4; indicating that these strains could tolerate passage through the gastrointestinal tract. All strains had robust growth in 0.1 and 0.5 M NaCl concentrations which mirror the small intestine, but differences were observed between strains in response to 1 M NaCl. Additionally, all strains tolerated up to 5% ethanol and 0.1% hydrogen peroxide. Biolog phenotypic microarrays revealed that A. calcoaceticus strains could use a range of nutrient sources, including monosaccharides, disaccharides, polymers, glycosides, acids, and amino acids. Interestingly, the commercially available A. calcoaceticus strains and one clinical isolate stimulated the pro-inflammatory cytokines Tnf, Kc, and Mcp-1 while all strains suppressed Muc13 and Muc2. Conclusion: Collectively, these data demonstrate that A. calcoaceticus is well adapted to dealing with environmental stressors of the gastrointestinal system. This data also points to the potential for Acinetobacter to influence the gut epithelium.
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Affiliation(s)
- Janiece S. Glover
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Brittney D. Browning
- Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC, United States
| | - Taylor D. Ticer
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
| | - Amy C. Engevik
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Melinda A. Engevik
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, United States
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, United States
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4
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Michel AM, Borrero-de Acuña JM, Molinari G, Ünal CM, Will S, Derksen E, Barthels S, Bartram W, Schrader M, Rohde M, Zhang H, Hoffmann T, Neumann-Schaal M, Bremer E, Jahn D. Cellular adaptation of Clostridioides difficile to high salinity encompasses a compatible solute-responsive change in cell morphology. Environ Microbiol 2022; 24:1499-1517. [PMID: 35106888 DOI: 10.1111/1462-2920.15925] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 11/27/2022]
Abstract
Infections by the pathogenic gut bacterium Clostridioides difficile cause severe diarrheas up to a toxic megacolon and are currently among the major causes of lethal bacterial infections. Successful bacterial propagation in the gut is strongly associated with the adaptation to changing nutrition-caused environmental conditions; e.g. environmental salt stresses. Concentrations of 350 mM NaCl, the prevailing salinity in the colon, led to significantly reduced growth of C. difficile. Metabolomics of salt- stressed bacteria revealed a major reduction of the central energy generation pathways, including the Stickland-fermentation reactions. No obvious synthesis of compatible solutes was observed up to 24 h of growth. The ensuing limited tolerance to high salinity and absence of compatible solute synthesis might result from an evolutionary adaptation to the exclusive life of C. difficile in the mammalian gut. Addition of the compatible solutes carnitine, glycine-betaine, γ-butyrobetaine, crotonobetaine, homobetaine, proline-betaine and dimethylsulfoniopropionate (DMSP) restored growth (choline and proline failed) under conditions of high salinity. A bioinformatically-identified OpuF-type ABC-transporter imported most of the used compatible solutes. A long-term adaptation after 48 h included a shift of the Stickland fermentation-based energy metabolism from the utilization to the accumulation of L-proline and resulted in restored growth. Surprisingly, salt stress resulted in the formation of coccoid C. difficile cells instead of the typical rod-shaped cells, a process reverted by the addition of several compatible solutes. Hence, compatible solute import via OpuF is the major immediate adaptation strategy of C. difficile to high salinity-incurred cellular stress. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Annika-Marisa Michel
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - José Manuel Borrero-de Acuña
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany.,Universidad de Sevilla, Facultad de Biología, Departamento de Microbiología, Av. de la Reina Mercedes, n° 6, CP, 41012, Sevilla, Spain
| | - Gabriella Molinari
- Central Facility for Microscopy, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Can Murat Ünal
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Sabine Will
- Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Elisabeth Derksen
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stefan Barthels
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Wiebke Bartram
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Michel Schrader
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - Hao Zhang
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,School of Life Science and Technology, Changchun University of Science and Technology, No. 7186 Weixing Road, 130022, Changchun, China
| | - Tamara Hoffmann
- Laboratory for Microbiology, Department of Biology, Philipps-Universität Marburg, Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
| | - Meina Neumann-Schaal
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany.,Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Erhard Bremer
- Laboratory for Microbiology, Department of Biology, Philipps-Universität Marburg, Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
| | - Dieter Jahn
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
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Chu N, Ling J, Jie H, Leung K, Poon E. The potential role of lactulose pharmacotherapy in the treatment and prevention of diabetes. Front Endocrinol (Lausanne) 2022; 13:956203. [PMID: 36187096 PMCID: PMC9519995 DOI: 10.3389/fendo.2022.956203] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
The non-absorbable disaccharide lactulose is mostly used in the treatment of various gastrointestinal disorders such as chronic constipation and hepatic encephalopathy. The mechanism of action of lactulose remains unclear, but it elicits more than osmotic laxative effects. As a prebiotic, lactulose may act as a bifidogenic factor with positive effects in preventing and controlling diabetes. In this review, we summarized the current evidence for the effect of lactulose on gut metabolism and type 2 diabetes (T2D) prevention. Similar to acarbose, lactulose can also increase the abundance of the short-chain fatty acid (SCFA)-producing bacteria Lactobacillus and Bifidobacterium as well as suppress the potentially pathogenic bacteria Escherichia coli. These bacterial activities have anti-inflammatory effects, nourishing the gut epithelial cells and providing a protective barrier from microorganism infection. Activation of peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP1) can influence secondary bile acids and reduce lipopolysaccharide (LPS) endotoxins. A low dose of lactulose with food delayed gastric emptying and increased the whole gut transit times, attenuating the hyperglycemic response without adverse gastrointestinal events. These findings suggest that lactulose may have a role as a pharmacotherapeutic agent in the management and prevention of type 2 diabetes via actions on the gut microbiota.
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6
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Nunez-Salces M, Li H, Young RL, Page AJ. The secretion of total and acyl ghrelin from the mouse gastric mucosa: Role of nutrients and the lipid chemosensors FFAR4 and CD36. Peptides 2021; 146:170673. [PMID: 34627956 DOI: 10.1016/j.peptides.2021.170673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022]
Abstract
AIMS This study investigated the nutrient-mediated modulation of total ghrelin (TG) and acyl ghrelin (AG) secretion from the mouse gastric mucosa, and the role of long-chain fatty acid chemosensors, FFAR4 and CD36, in lipid-mediated modulation of TG and AG release. METHODS Ex-vivo experiments were conducted using mouse gastric mucosa to examine the effects of nutrients (D-glucose, L-phenylalanine, peptone (mixture of oligopeptides & single amino acids), D-mannitol, α-linolenic acid and fat emulsion (intralipid)) on TG and AG secretion. Additionally, inhibition of FFAR4 and CD36 on α-linolenic acid and intralipid-mediated regulation of TG and AG secretion was assessed. RESULTS TG and AG secretion were unaffected by glucose and D-mannitol. Peptone stimulated the release of TG and AG. In contrast, L-phenylalanine reduced AG secretion only. Intralipid reduced TG secretion and stimulated AG secretion, and α-linolenic acid reduced AG release, without affecting TG mobilisation. Modulation of ghrelin secretion by lipids occurred in an FFAR4 and CD36-independent manner. CONCLUSION Ghrelin secretion is modulated in a nutrient-specific manner by proteins and lipids, with TG and AG displaying independent responses to the same stimuli. In addition, FFAR4 and CD36 do not participate in modulation of TG and AG secretion by α-linolenic acid and intralipid.
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Affiliation(s)
- Maria Nunez-Salces
- Vagal Afferent Research Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Hui Li
- Vagal Afferent Research Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Richard L Young
- Intestinal Nutrient Sensing Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Australia; Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia; Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia.
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7
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Li JV, Ashrafian H, Sarafian M, Homola D, Rushton L, Barker G, Cabrera PM, Lewis MR, Darzi A, Lin E, Gletsu-Miller NA, Atkin SL, Sathyapalan T, Gooderham NJ, Nicholson JK, Marchesi JR, Athanasiou T, Holmes E. Roux-en-Y gastric bypass-induced bacterial perturbation contributes to altered host-bacterial co-metabolic phenotype. MICROBIOME 2021; 9:139. [PMID: 34127058 PMCID: PMC8201742 DOI: 10.1186/s40168-021-01086-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 04/27/2021] [Indexed: 05/04/2023]
Abstract
BACKGROUND Bariatric surgery, used to achieve effective weight loss in individuals with severe obesity, modifies the gut microbiota and systemic metabolism in both humans and animal models. The aim of the current study was to understand better the metabolic functions of the altered gut microbiome by conducting deep phenotyping of bariatric surgery patients and bacterial culturing to investigate causality of the metabolic observations. METHODS Three bariatric cohorts (n = 84, n = 14 and n = 9) with patients who had undergone Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG) or laparoscopic gastric banding (LGB), respectively, were enrolled. Metabolic and 16S rRNA bacterial profiles were compared between pre- and post-surgery. Faeces from RYGB patients and bacterial isolates were cultured to experimentally associate the observed metabolic changes in biofluids with the altered gut microbiome. RESULTS Compared to SG and LGB, RYGB induced the greatest weight loss and most profound metabolic and bacterial changes. RYGB patients showed increased aromatic amino acids-based host-bacterial co-metabolism, resulting in increased urinary excretion of 4-hydroxyphenylacetate, phenylacetylglutamine, 4-cresyl sulphate and indoxyl sulphate, and increased faecal excretion of tyramine and phenylacetate. Bacterial degradation of choline was increased as evidenced by altered urinary trimethylamine-N-oxide and dimethylamine excretion and faecal concentrations of dimethylamine. RYGB patients' bacteria had a greater capacity to produce tyramine from tyrosine, phenylalanine to phenylacetate and tryptophan to indole and tryptamine, compared to the microbiota from non-surgery, normal weight individuals. 3-Hydroxydicarboxylic acid metabolism and urinary excretion of primary bile acids, serum BCAAs and dimethyl sulfone were also perturbed following bariatric surgery. CONCLUSION Altered bacterial composition and metabolism contribute to metabolic observations in biofluids of patients following RYGB surgery. The impact of these changes on the functional clinical outcomes requires further investigation. Video abstract.
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Affiliation(s)
- Jia V Li
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Hutan Ashrafian
- Division of Surgery, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, UK
| | - Magali Sarafian
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Daniel Homola
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Laura Rushton
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
- Division of Systems Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Grace Barker
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Paula Momo Cabrera
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Matthew R Lewis
- Division of Systems Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Ara Darzi
- Division of Surgery, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, UK
| | - Edward Lin
- Division of General and Gastrointestinal Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, Georgia, 30322, USA
| | - Nana Adwoa Gletsu-Miller
- Department of Applied Health Science, School of Public Health, Indiana University Bloomington, 1025 E 7th Street, Bloomington, IN, 47405, USA
| | | | - Thozhukat Sathyapalan
- Department of Academic Endocrinology, Diabetes and Metabolism, Hull-York Medical School, Hull, UK
| | - Nigel J Gooderham
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Jeremy K Nicholson
- Centre for Computational and Systems Medicine, The Health Futures Institute, Murdoch University, Harry Perkins Building, Perth, WA, 6150, Australia
| | - Julian R Marchesi
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
| | - Thanos Athanasiou
- Division of Surgery, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, UK
| | - Elaine Holmes
- Division of Digestive Disease, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK.
- Centre for Computational and Systems Medicine, The Health Futures Institute, Murdoch University, Harry Perkins Building, Perth, WA, 6150, Australia.
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Nunez‐Salces M, Li H, Feinle‐Bisset C, Young RL, Page AJ. The regulation of gastric ghrelin secretion. Acta Physiol (Oxf) 2021; 231:e13588. [PMID: 33249751 DOI: 10.1111/apha.13588] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022]
Abstract
Ghrelin is a gastric hormone with multiple physiological functions, including the stimulation of food intake and adiposity. It is well established that circulating ghrelin levels are closely associated with feeding patterns, rising strongly before a meal and lowering upon food intake. However, the mechanisms underlying the modulation of ghrelin secretion are not fully understood. The purpose of this review is to discuss current knowledge on the circadian oscillation of circulating ghrelin levels, the neural mechanisms stimulating fasting ghrelin levels and peripheral mechanisms modulating postprandial ghrelin levels. Furthermore, the therapeutic potential of targeting the ghrelin pathway is discussed in the context of the treatment of various metabolic disorders, including obesity, type 2 diabetes, diabetic gastroparesis and Prader-Willi syndrome. Moreover, eating disorders including anorexia nervosa, bulimia nervosa and binge-eating disorder are also discussed.
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Affiliation(s)
- Maria Nunez‐Salces
- Vagal Afferent Research Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
| | - Hui Li
- Vagal Afferent Research Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
| | - Christine Feinle‐Bisset
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
| | - Richard L. Young
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
- Intestinal Nutrient Sensing Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
| | - Amanda J. Page
- Vagal Afferent Research Group Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health Adelaide Medical School The University of Adelaide Adelaide SA Australia
- Nutrition, Diabetes & Gut Health, Lifelong Health Theme South Australian Health & Medical Research Institute (SAHMRI) Adelaide SA Australia
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Thiemicke A, Neuert G. Kinetics of osmotic stress regulate a cell fate switch of cell survival. SCIENCE ADVANCES 2021; 7:7/8/eabe1122. [PMID: 33608274 PMCID: PMC7895434 DOI: 10.1126/sciadv.abe1122] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/06/2021] [Indexed: 05/02/2023]
Abstract
Exposure of cells to diverse types of stressful environments differentially regulates cell fate. Although many types of stresses causing this differential regulation are known, it is unknown how changes over time of the same stressor regulate cell fate. Changes in extracellular osmolarity are critically involved in physiological and pathophysiological processes in several tissues. We observe that human cells survive gradual but not acute hyperosmotic stress. We find that stress, caspase, and apoptosis signaling do not activate during gradual stress in contrast to acute treatments. Contrary to the current paradigm, we see a substantial accumulation of proline in cells treated with gradual but not acute stresses. We show that proline can protect cells from hyperosmotic stress similar to the osmoprotection in plants and bacteria. Our studies found a cell fate switch that enables cells to survive gradually changing stress environments by preventing caspase activation and protect cells through proline accumulation.
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Affiliation(s)
- Alexander Thiemicke
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Gregor Neuert
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, USA.
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, TN, USA
- Department of Biomedical Engineering, School of Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, USA
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Sorrentino ZA, Smith G, Palm L, Motwani K, Butterfield J, Archer C, Henderson R, Heldermon C, Gautam S, Brantly ML. An Erythritol-Sweetened Beverage Induces Satiety and Suppresses Ghrelin Compared to Aspartame in Healthy Non-Obese Subjects: A Pilot Study. Cureus 2020; 12:e11409. [PMID: 33194505 PMCID: PMC7657312 DOI: 10.7759/cureus.11409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 11/09/2020] [Indexed: 11/28/2022] Open
Abstract
Despite the reduced caloric content of artificially sweetened beverages (ASBs) relative to those sweetened with sucrose, consumption of ASBs fail to consistently decrease the risk of obesity and associated diseases. This failure may be due to the inability of ASBs to effectively reduce appetite and hence overall caloric intake. A variety of non-nutritive sweeteners (NNS), however, remain to be screened for effectiveness in promoting satiety and reducing calorie consumption. Erythritol is well-tolerated, low-calorie sugar alcohol widely used as a sugar substitute. It is unique among NNS due to its low sweetness index relative to glucose, meaning that it is typically served at much higher concentrations than other common NNS. Animal and human studies have noted correlations between osmolarity, satiety, and levels of satiety hormones, independent of the effects of sweetness or nutritive value. We hypothesized that consumption of a beverage sweetened with erythritol to the sweetness and osmolarity of a common soft drink will improve self-reported satiety and more strongly affect the magnitude of changes in the hormone ghrelin than would an iso sweet beverage sweetened only with aspartame, a sweetener with a high sweetness index relative to glucose. Using a randomized double-blind crossover trial, we found that serum ghrelin was significantly decreased after consumption of an erythritol-sweetened beverage compared to aspartame. Likewise, consumption of the erythritol-sweetened beverage increased various measures of satiety in volunteers. Knowledge gained from this project demonstrates that high-osmolarity NNS may be useful in formulating ASBs that are satiating and low in calories.
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Affiliation(s)
| | - Garrett Smith
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - Lindsey Palm
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - Kartik Motwani
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - John Butterfield
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - Christian Archer
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - Rebecca Henderson
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - Coy Heldermon
- Medicine, University of Florida College of Medicine, Gainesville, USA
| | - Shiva Gautam
- Medicine, University of Florida College of Medicine, Jacksonville, USA
| | - Mark L Brantly
- Medicine, University of Florida College of Medicine, Gainesville, USA
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11
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Li Y, Chen M, Hu J, Sheng R, Lin Q, He X, Guo M. Volumetric Compression Induces Intracellular Crowding to Control Intestinal Organoid Growth via Wnt/β-Catenin Signaling. Cell Stem Cell 2020; 28:63-78.e7. [PMID: 33053374 DOI: 10.1016/j.stem.2020.09.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 02/26/2020] [Accepted: 09/14/2020] [Indexed: 12/14/2022]
Abstract
Enormous amounts of essential intracellular events are crowdedly packed inside picoliter-sized cellular space. However, the significance of the physical properties of cells remains underappreciated because of a lack of evidence of how they affect cellular functionalities. Here, we show that volumetric compression regulates the growth of intestinal organoids by modifying intracellular crowding and elevating Wnt/β-catenin signaling. Intracellular crowding varies upon stimulation by different types of extracellular physical/mechanical cues and leads to significant enhancement of Wnt/β-catenin signaling by stabilizing the LRP6 signalosome. By enhancing intracellular crowding using osmotic and mechanical compression, we show that expansion of intestinal organoids was facilitated through elevated Wnt/β-catenin signaling and greater intestinal stem cell (ISC) self-renewal. Our results provide an entry point for understanding how intracellular crowdedness functions as a physical regulator linking extracellular physical cues with intracellular signaling and potentially facilitate the design of engineering approaches for expansion of stem cells and organoids.
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Affiliation(s)
- Yiwei Li
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Maorong Chen
- F. M. Kirby Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jiliang Hu
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ren Sheng
- F. M. Kirby Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; College of Life and Health Science, Northeastern University, Shenyang, Liaoning, 110004, China
| | - Qirong Lin
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xi He
- F. M. Kirby Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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12
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Yang J, Zhang H, Sun S, Wang X, Guan Y, Mi Q, Zeng W, Xiang H, Zhu H, Zou X, You Y, Xiang Y, Gao Q. Autophagy and Hsp70 activation alleviate oral epithelial cell death induced by food-derived hypertonicity. Cell Stress Chaperones 2020; 25:253-264. [PMID: 31975220 PMCID: PMC7058754 DOI: 10.1007/s12192-020-01068-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/12/2019] [Accepted: 01/06/2020] [Indexed: 01/16/2023] Open
Abstract
Stable intracellular and intercellular osmolarity is vital for all physiological processes. Although it is the first organ that receives food, the osmolarity around the mouth epithelium has never been systematically investigated. We found that oral epithelial cells are a population of ignored cells routinely exposed to hypertonic environments mainly composed of saline, glucose, etc. in vivo after chewing food. By using cultured oral epithelial cells as an in vitro model, we found that the hypotonic environments caused by both high NaCl and high glucose induced cell death in a dose- and time-dependent manner. Transcriptomics revealed similar expression profiles after high NaCl and high glucose stimulation. Most of the common differentially expressed genes were enriched in "mitophagy" and "autophagy" according to KEGG pathway enrichment analysis. Hypertonic stimulation for 1 to 6 h resulted in autophagosome formation. The activation of autophagy protected cells from high osmolarity-induced cell death. The activation of Hsp70 by the pharmacological activator handelin significantly improved the cell survival rate after hypertonic stimulation. The protective role of Hsp70 activation was partially dependent on autophagy activation, indicating a crosstalk between Hsp70 and autophagy in hypertonic stress response. The extract of the handelin-containing herb Chrysanthemum indicum significantly protected oral epithelial cells from hypertonic-induced death, providing an inexpensive way to protect against hypertonic-induced oral epithelial damage. In conclusion, the present study emphasized the importance of changes in osmolarity in oral health for the first time. The identification of novel compounds or herbal plant extracts that can activate autophagy or HSPs may contribute to oral health and the food industry.
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Affiliation(s)
- Ji Yang
- Technology Center of China Tobacco Yunnan Industrial Co. Ltd., No. 41 Keyi Road, Kunming, 650106, China
| | - Huijie Zhang
- Key Laboratory of Human Aging in Jiangxi Province, Human Aging Research Institute, Nanchang University, No. 999 Xuefu Road, Nanchang, 330031, China
| | - Sujiao Sun
- Medical Cosmetology Teaching and Research Section, School of Clinical Medicine, Dali University, No.32 Jiashibo Road, Dali, 532901, China
| | - Xue Wang
- School of Pharmaceutical Science &Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, No. 1168 West Chunrong Road, Kunming, 650504, China
| | - Ying Guan
- Technology Center of China Tobacco Yunnan Industrial Co. Ltd., No. 41 Keyi Road, Kunming, 650106, China
| | - Qili Mi
- Technology Center of China Tobacco Yunnan Industrial Co. Ltd., No. 41 Keyi Road, Kunming, 650106, China
| | - Wanli Zeng
- Technology Center of China Tobacco Yunnan Industrial Co. Ltd., No. 41 Keyi Road, Kunming, 650106, China
| | - Haiying Xiang
- Technology Center of China Tobacco Yunnan Industrial Co. Ltd., No. 41 Keyi Road, Kunming, 650106, China
| | - Huadong Zhu
- Key Laboratory of Human Aging in Jiangxi Province, Human Aging Research Institute, Nanchang University, No. 999 Xuefu Road, Nanchang, 330031, China
| | - Xin Zou
- Key Laboratory of Human Aging in Jiangxi Province, Human Aging Research Institute, Nanchang University, No. 999 Xuefu Road, Nanchang, 330031, China
| | - Yunfei You
- Key Laboratory of Human Aging in Jiangxi Province, Human Aging Research Institute, Nanchang University, No. 999 Xuefu Road, Nanchang, 330031, China
| | - Yang Xiang
- Key Laboratory of Human Aging in Jiangxi Province, Human Aging Research Institute, Nanchang University, No. 999 Xuefu Road, Nanchang, 330031, China.
| | - Qian Gao
- Technology Center of China Tobacco Yunnan Industrial Co. Ltd., No. 41 Keyi Road, Kunming, 650106, China.
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13
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Sun X, Yi Y, Liang B, Yang Y, He N, Ode KL, Uc A, Wang K, Gibson-Corley KN, Engelhardt JF, Norris AW. Incretin dysfunction and hyperglycemia in cystic fibrosis: Role of acyl-ghrelin. J Cyst Fibros 2019; 18:557-565. [PMID: 30738804 DOI: 10.1016/j.jcf.2019.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 01/05/2019] [Accepted: 01/21/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Insulin secretion is insufficient in cystic fibrosis (CF), even before diabetes is present, though the mechanisms involved remain unclear. Acyl-ghrelin (AG) can diminish insulin secretion and is elevated in humans with CF. METHODS We tested the hypothesis that elevated AG contributes to reduced insulin secretion and hyperglycemia in CF ferrets. RESULTS Fasting AG was elevated in CF versus non-CF ferrets. Similar to its effects in other species, AG administration in non-CF ferrets acutely reduced insulin, increased growth hormone, and induced hyperglycemia. During oral glucose tolerance testing, non-CF ferrets had responsive insulin, glucagon like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) levels and maintained normal glucose levels, whereas CF ferrets had insufficient responses and became hyperglycemic. Interestingly in wild-type ferrets, the acyl-ghrelin receptor antagonist [D-Lys3]-GHRP-6 impaired glucose tolerance, and abolished insulin, GLP-1, and GIP responses during glucose tolerance testing. By contrast, in CF ferrets [D-Lys3]-GHRP-6 improved glucose tolerance, enhanced the insulin-to-glucose ratio, but did not impact the already low GLP-1 and GIP levels. CONCLUSIONS These results suggest a mechanism by which elevated AG contributes to CF hyperglycemia through inhibition of insulin secretion, an effect magnified by low GLP-1 and GIP. Interventions that lower ghrelin, ghrelin action, and/or raise GLP-1 or GIP might improve glycemia in CF.
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Affiliation(s)
- Xingshen Sun
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Yaling Yi
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Bo Liang
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Yu Yang
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Nan He
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Katie Larson Ode
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Aliye Uc
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Kai Wang
- Department of Biostatistics, University of Iowa, Iowa City, IA 52242, USA
| | - Katherine N Gibson-Corley
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pathology, University of Iowa, Iowa City, IA 52242, USA
| | - John F Engelhardt
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA.
| | - Andrew W Norris
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA; Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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14
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Veedfald S, Wu T, Bound M, Grivell J, Hartmann B, Rehfeld JF, Deacon CF, Horowitz M, Holst JJ, Rayner CK. Hyperosmolar Duodenal Saline Infusion Lowers Circulating Ghrelin and Stimulates Intestinal Hormone Release in Young Men. J Clin Endocrinol Metab 2018; 103:4409-4418. [PMID: 30053031 DOI: 10.1210/jc.2018-00699] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/17/2018] [Indexed: 02/07/2023]
Abstract
CONTEXT The mechanisms regulating the postprandial suppression of ghrelin secretion remain unclear, but recent observations in rats indicate that an increase in duodenal osmolarity is associated with a reduction in ghrelin levels. Several hormones have been implicated in the regulation of ghrelin. OBJECTIVE We hypothesized that intraduodenal infusion of a hyperosmolar solution would lower plasma ghrelin concentrations. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTIONS Eighteen healthy young men were studied after an overnight fast on two occasions in a randomized double-blinded fashion. A nasoduodenal catheter was positioned and isoosmolar (300 mOsm/L) or hyperosmolar (1500 mOsm/L) saline was infused intraduodenally (4 mL/min, t = 0 to 45 minutes). Venous blood was sampled at t = -45, -30, -15, 0, 15, 30, 45, 60, 75, 90, 120, and 180 minutes. MAIN OUTCOME MEASURES Plasma concentrations of ghrelin, glucagonlike peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), cholecystokinin (CCK), glucagon, pancreatic polypeptide (PP), neurotensin (NT), peptide YY (PYY), motilin, and glucose. RESULTS Ghrelin concentrations were suppressed with hyperosmolar when compared with isoosmolar saline, and remained lower until t = 180 minutes. CCK, NT, GLP-1, PYY, and glucagon all increased during hyperosmolar, but not isoosmolar, saline infusion (P < 0.01 for all), whereas GIP, PP, and motilin levels were not affected by either infusion. CONCLUSIONS Plasma ghrelin concentrations are lowered, whereas CCK, GLP-1, PYY, NT, and glucagon concentrations are augmented, by hyperosmolar duodenal content in healthy individuals. These observations have implications for the evaluation of studies comparing the effects of different types and loads of nutrients and chemicals on gut hormone secretion.
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Affiliation(s)
- Simon Veedfald
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tongzhi Wu
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Michelle Bound
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Jacqueline Grivell
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Bolette Hartmann
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens F Rehfeld
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Carolyn F Deacon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Michael Horowitz
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
| | - Jens J Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Christopher K Rayner
- Discipline of Medicine and National Health and Medical Research Council Centre of Research Excellence in Nutritional Physiology, Interventions and Outcomes, University of Adelaide, Adelaide, South Australia, Australia
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15
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Xiong X, Bales ES, Ir D, Robertson CE, McManaman JL, Frank DN, Parkinson J. Perilipin-2 modulates dietary fat-induced microbial global gene expression profiles in the mouse intestine. MICROBIOME 2017; 5:117. [PMID: 28877764 PMCID: PMC5588750 DOI: 10.1186/s40168-017-0327-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 08/20/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Intestinal microbiota are critical determinants of obesity and metabolic disease risk. In previous work, we showed that deletion of the cytoplasmic lipid droplet (CLD) protein perilipin-2 (Plin2) modulates gut microbial community structure and abrogates long-term deleterious effects of a high-fat (HF) diet in mice. However, the impact of Plin2 on microbiome function is unknown. RESULTS Here, we used metatranscriptomics to identify differences in microbiome transcript expression in WT and Plin2-null mice following acute exposure to high-fat/low-carbohydrate (HF) or low-fat/high-carbohydrate (LF) diets. Consistent with previous studies, dietary changes resulted in significant taxonomic shifts. Unexpectedly, when fed a HF diet, the microbiota of Plin2-null and WT mice exhibited dramatic shifts in transcript expression despite no discernible shift in community structure. For Plin2-null mice, these changes included the coordinated upregulation of metabolic enzymes directing flux towards the production of growth metabolites such as fatty acids, nucleotides, and amino acids. In contrast, the LF diet did not appear to induce the same dramatic changes in transcript or pathway expression between the two genotypes. CONCLUSIONS Our data shows that a host genotype can modulate microbiome function without impacting community structure and identify Plin2 as a specific host determinant of diet effects on microbial function. Along with uncovering potential mechanisms for integrating how diet modulates host and microbial metabolism, our findings demonstrate the limits of 16S rRNA surveys to inform on community functional activities and the need to prioritize metatranscriptomic studies to gain more meaningful insights into microbiome function.
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Affiliation(s)
- Xuejian Xiong
- Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, M5G 0A4 ON Canada
| | - Elise S. Bales
- Division of Reproductive Sciences, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
| | - Diana Ir
- Division of Infectious Diseases, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
| | - Charles E. Robertson
- Division of Infectious Diseases, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
- Microbiome Research Consortium, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
| | - James L. McManaman
- Division of Reproductive Sciences, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
- The Center for Human Nutrition, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
| | - Daniel N. Frank
- Division of Infectious Diseases, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
- Microbiome Research Consortium, University of Colorado, 12700 E. 19th Avenue, Aurora, 80045 CO USA
| | - John Parkinson
- Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, M5G 0A4 ON Canada
- Department of Molecular Genetics, University of Toronto, 1 King’s College Circle, Toronto, M5S 1A8 ON Canada
- Department of Biochemistry, University of Toronto, 1 King’s College Circle, Toronto, M5S 1A8 ON Canada
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16
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Tamboli RA, Sidani RM, Garcia AE, Antoun J, Isbell JM, Albaugh VL, Abumrad NN. Jejunal administration of glucose enhances acyl ghrelin suppression in obese humans. Am J Physiol Endocrinol Metab 2016; 311:E252-9. [PMID: 27279247 PMCID: PMC4967145 DOI: 10.1152/ajpendo.00082.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/26/2016] [Indexed: 01/03/2023]
Abstract
Ghrelin is a gastric hormone that stimulates hunger and worsens glucose metabolism. Circulating ghrelin is decreased after Roux-en-Y gastric bypass (RYGB) surgery; however, the mechanism(s) underlying this change is unknown. We tested the hypothesis that jejunal nutrient exposure plays a significant role in ghrelin suppression after RYGB. Feeding tubes were placed in the stomach or jejunum in 13 obese subjects to simulate pre-RYGB or post-RYGB glucose exposure to the gastrointestinal (GI) tract, respectively, without the confounding effects of caloric restriction, weight loss, and surgical stress. On separate study days, the plasma glucose curves obtained with either gastric or jejunal administration of glucose were replicated with intravenous (iv) infusions of glucose. These "isoglycemic clamps" enabled us to determine the contribution of the GI tract and postabsorptive plasma glucose to acyl ghrelin suppression. Plasma acyl ghrelin levels were suppressed to a greater degree with jejunal glucose administration compared with gastric glucose administration (P < 0.05). Jejunal administration of glucose also resulted in a greater suppression of acyl ghrelin than the corresponding isoglycemic glucose infusion (P ≤ 0.01). However, gastric and isoglycemic iv glucose infusions resulted in similar degrees of acyl ghrelin suppression (P > 0.05). Direct exposure of the proximal jejunum to glucose increases acyl ghrelin suppression independent of circulating glucose levels. The enhanced suppression of acyl ghrelin after RYGB may be due to a nutrient-initiated signal in the jejunum that regulates ghrelin secretion.
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Affiliation(s)
- Robyn A Tamboli
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Reem M Sidani
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Anna E Garcia
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Joseph Antoun
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - James M Isbell
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Vance L Albaugh
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Naji N Abumrad
- Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
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