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Dr. Jekyll and Mr. Hide: How Enterococcus faecalis Subverts the Host Immune Response to Cause Infection. J Mol Biol 2019; 431:2932-2945. [DOI: 10.1016/j.jmb.2019.05.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 05/15/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023]
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Enterococcus faecalis Gluconate Phosphotransferase System Accelerates Experimental Colitis and Bacterial Killing by Macrophages. Infect Immun 2019; 87:IAI.00080-19. [PMID: 31036600 DOI: 10.1128/iai.00080-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/21/2019] [Indexed: 02/07/2023] Open
Abstract
Enterococcus faecalis strains are resident intestinal bacteria associated with invasive infections, inflammatory bowel diseases, and colon cancer. Although factors promoting E. faecalis colonization of intestines are not fully known, one implicated pathway is a phosphotransferase system (PTS) in E. faecalis strain OG1RF that phosphorylates gluconate and contains the genes OG1RF_12399 to OG1RF_12402 (OG1RF_12399-12402). We hypothesize that this PTS permits growth in gluconate, facilitates E. faecalis intestinal colonization, and exacerbates colitis. We generated E. faecalis strains containing deletions/point mutations in this PTS and measured bacterial growth and PTS gene expression in minimal medium supplemented with selected carbohydrates. We show that E. faecalis upregulates OG1RF_12399 transcription specifically in the presence of gluconate and that E. faecalis strains lacking, or harboring a single point mutation in, OG1RF_12399-12402 are unable to grow in minimal medium containing gluconate. We colonized germfree wild-type and colitis-prone interleukin-10-deficient mice with defined bacterial consortia containing the E. faecalis strains and measured inflammation and bacterial abundance in the colon. We infected macrophage and intestinal epithelial cell lines with the E. faecalis strains and measured intracellular bacterial survival and proinflammatory cytokine secretion. The presence of OG1RF_12399-12402 is not required for E. faecalis colonization of the mouse intestine but is associated with an accelerated onset of experimental colitis in interleukin-10-deficient mice, altered bacterial composition in the colon, enhanced E. faecalis survival within macrophages, and increased proinflammatory cytokine secretion by colon tissue and macrophages. Further studies of bacterial carbohydrate metabolism in general, and E. faecalis PTS-gluconate in particular, during inflammation may identify new mechanisms of disease pathogenesis.
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Lengfelder I, Sava IG, Hansen JJ, Kleigrewe K, Herzog J, Neuhaus K, Hofmann T, Sartor RB, Haller D. Complex Bacterial Consortia Reprogram the Colitogenic Activity of Enterococcus faecalis in a Gnotobiotic Mouse Model of Chronic, Immune-Mediated Colitis. Front Immunol 2019; 10:1420. [PMID: 31281321 PMCID: PMC6596359 DOI: 10.3389/fimmu.2019.01420] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/05/2019] [Indexed: 12/17/2022] Open
Abstract
Inflammatory bowel diseases (IBD) are associated with compositional and functional changes of the intestinal microbiota, but specific contributions of individual bacteria to chronic intestinal inflammation remain unclear. Enterococcus faecalis is a resident member of the human intestinal core microbiota that has been linked to the pathogenesis of IBD and induces chronic colitis in susceptible monoassociated IL-10-deficient (IL-10−/−) mice. In this study, we characterized the colitogenic activity of E. faecalis as part of a simplified human microbial consortium based on seven enteric bacterial strains (SIHUMI). RNA sequencing analysis of E. faecalis isolated from monoassociated wild type and IL-10−/− mice identified 408 genes including 14 genes of the ethanolamine utilization (eut) locus that were significantly up-regulated in response to inflammation. Despite considerable up-regulation of eut genes, deletion of ethanolamine utilization (ΔeutVW) had no impact on E. faecalis colitogenic activity in monoassociated IL-10−/− mice. However, replacement of the E. faecalis wild type bacteria by a ΔeutVW mutant in SIHUMI-colonized IL-10−/− mice resulted in exacerbated colitis, suggesting protective functions of E. faecalis ethanolamine utilization in complex bacterial communities. To better understand E. faecalis gene response in the presence of other microbes, we purified wild type E. faecalis cells from the colon content of SIHUMI-colonized wild type and IL-10−/− mice using immuno-magnetic separation and performed RNA sequencing. Transcriptional profiling revealed that the bacterial environment reprograms E. faecalis gene expression in response to inflammation, with the majority of differentially expressed genes not being shared between monocolonized and SIHUMI conditions. While in E. faecalis monoassociation a general bacterial stress response could be observed, expression of E. faecalis genes in SIHUMI-colonized mice was characterized by up-regulation of genes involved in growth and replication. Interestingly, in mice colonized with SIHUMI lacking E. faecalis enhanced inflammation was observed in comparison to SIHUMI-colonized mice, supporting the hypothesis that E. faecalis ethanolamine metabolism protects against colitis in complex consortia. In conclusion, this study demonstrates that complex bacterial consortia interactions reprogram the gene expression profile and colitogenic activity of the opportunistic pathogen E. faecalis toward a protective function.
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Affiliation(s)
- Isabella Lengfelder
- Chair of Nutrition and Immunology, Technische Universität München, Freising, Germany
| | - Irina G Sava
- Chair of Nutrition and Immunology, Technische Universität München, Freising, Germany
| | - Jonathan J Hansen
- Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC, United States
| | - Karin Kleigrewe
- Bavarian Center for Biomolecular Mass Spectrometry, Technische Universität München, Freising, Germany
| | - Jeremy Herzog
- Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC, United States
| | - Klaus Neuhaus
- ZIEL - Institute for Food & Health, Technische Universität München, Freising, Germany.,ZIEL Core Facility Microbiome, Technische Universität München, Freising, Germany
| | - Thomas Hofmann
- Bavarian Center for Biomolecular Mass Spectrometry, Technische Universität München, Freising, Germany.,ZIEL - Institute for Food & Health, Technische Universität München, Freising, Germany
| | - R Balfour Sartor
- Division of Gastroenterology and Hepatology, University of North Carolina, Chapel Hill, NC, United States
| | - Dirk Haller
- Chair of Nutrition and Immunology, Technische Universität München, Freising, Germany.,ZIEL - Institute for Food & Health, Technische Universität München, Freising, Germany
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Chen CC, Chen YN, Liou JM, Wu MS. From germ theory to germ therapy. Kaohsiung J Med Sci 2019; 35:73-82. [DOI: 10.1002/kjm2.12011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 11/22/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Chieh-Chang Chen
- Division of Gastroenterology and Hepatology, Department of Internal Medicine; National Taiwan University Hospital; Taipei Taiwan
- Department of Internal Medicine, College of Medicine; National Taiwan University; Taipei Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine; National Taiwan University; Taipei Taiwan
| | - Yen-Nien Chen
- Division of Gastroenterology and Hepatology, Department of Internal Medicine; National Taiwan University Hospital; Taipei Taiwan
- Department of Internal Medicine, College of Medicine; National Taiwan University; Taipei Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine; National Taiwan University; Taipei Taiwan
| | - Jyh-Ming Liou
- Division of Gastroenterology and Hepatology, Department of Internal Medicine; National Taiwan University Hospital; Taipei Taiwan
- Department of Internal Medicine, College of Medicine; National Taiwan University; Taipei Taiwan
| | - Ming-Shiang Wu
- Division of Gastroenterology and Hepatology, Department of Internal Medicine; National Taiwan University Hospital; Taipei Taiwan
- Department of Internal Medicine, College of Medicine; National Taiwan University; Taipei Taiwan
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55
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Khalil M, Zhang Z, Engel MA. Neuro-Immune Networks in Gastrointestinal Disorders. Visc Med 2019; 35:52-60. [PMID: 31312651 DOI: 10.1159/000496838] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/11/2019] [Indexed: 12/13/2022] Open
Abstract
Tissue homeostasis is controlled by multilateral cell interactions. Established in autoimmune diseases of the central nervous system, growing evidence shows a fundamental role of bidirectional communication between the nervous and immune systems in various gastrointestinal disorders. Primarily the primary sensory nervous system seems to play an important role in this cross talk because of its ability for transducing inflammatory signals and to convey them to the central nervous system, which in turn responds in an efferent manner (gut-brain axis vs. brain-gut axis). Moreover, sensory neurons that play a central role in pain processing immediately respond to inflammatory stimuli through releasing a myriad of immunomodulatory neuropeptides and neurotransmitters whose receptors are expressed in different immune cell populations. Thus, a better understanding of neuro-immune networks will pave the way to novel therapeutic strategies in inflammatory as well as functional gastrointestinal disorders.
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Affiliation(s)
- Mohammad Khalil
- Department of Medicine 1, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Zehua Zhang
- Department of Medicine 1, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Matthias A Engel
- Department of Medicine 1, Universitätsklinikum Erlangen, Erlangen, Germany
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56
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Yu LCH. Microbiota dysbiosis and barrier dysfunction in inflammatory bowel disease and colorectal cancers: exploring a common ground hypothesis. J Biomed Sci 2018; 25:79. [PMID: 30413188 PMCID: PMC6234774 DOI: 10.1186/s12929-018-0483-8] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023] Open
Abstract
Inflammatory bowel disease (IBD) is a multifactorial disease which arises as a result of the interaction of genetic, environmental, barrier and microbial factors leading to chronic inflammation in the intestine. Patients with IBD had a higher risk of developing colorectal carcinoma (CRC), of which the subset was classified as colitis-associated cancers. Genetic polymorphism of innate immune receptors had long been considered a major risk factor for IBD, and the mutations were also recently observed in CRC. Altered microbial composition (termed microbiota dybiosis) and dysfunctional gut barrier manifested by epithelial hyperpermeability and high amount of mucosa-associated bacteria were observed in IBD and CRC patients. The findings suggested that aberrant immune responses to penetrating commensal microbes may play key roles in fueling disease progression. Accumulative evidence demonstrated that mucosa-associated bacteria harbored colitogenic and protumoral properties in experimental models, supporting an active role of bacteria as pathobionts (commensal-derived opportunistic pathogens). Nevertheless, the host factors involved in bacterial dysbiosis and conversion mechanisms from lumen-dwelling commensals to mucosal pathobionts remain unclear. Based on the observation of gut leakiness in patients and the evidence of epithelial hyperpermeability prior to the onset of mucosal histopathology in colitic animals, it was postulated that the epithelial barrier dysfunction associated with mucosal enrichment of specific bacterial strains may predispose the shift to disease-associated microbiota. The speculation of leaky gut as an initiating factor for microbiota dysbiosis that eventually led to pathological consequences was proposed as the "common ground hypothesis", which will be highlighted in this review. Overall, the understanding of the core interplay between gut microbiota and epithelial barriers at early subclinical phases will shed light to novel therapeutic strategies to manage chronic inflammatory disorders and colitis-associated cancers.
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Affiliation(s)
- Linda Chia-Hui Yu
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Suite 1020, #1 Jen-Ai Rd. Sec. 1, Taipei, 100, Taiwan, Republic of China.
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57
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Jie Z, Yang JY, Gu M, Wang H, Xie X, Li Y, Liu T, Zhu L, Shi J, Zhang L, Zhou X, Joo D, Brightbill HD, Cong Y, Lin D, Cheng X, Sun SC. NIK signaling axis regulates dendritic cell function in intestinal immunity and homeostasis. Nat Immunol 2018; 19:1224-1235. [PMID: 30250187 PMCID: PMC6195481 DOI: 10.1038/s41590-018-0206-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 08/13/2018] [Indexed: 12/12/2022]
Abstract
Dendritic cells (DCs) play an integral role in regulating mucosal immunity and homeostasis, but the signaling network mediating this function of DCs is poorly defined. We identified the noncanonical NF-κB-inducing kinase (NIK) as a crucial mediator of mucosal DC function. DC-specific NIK deletion impaired intestinal immunoglobulin A (IgA) secretion and microbiota homeostasis, rendering mice sensitive to an intestinal pathogen, Citrobacter rodentium. DC-specific NIK was required for expression of the IgA transporter polymeric immunoglobulin receptor (pIgR) in intestinal epithelial cells, which in turn relied on the cytokine IL-17 produced by TH17 cells and innate lymphoid cells (ILCs). NIK-activated noncanonical NF-κB induced expression of IL-23 in DCs, contributing to the maintenance of TH17 cells and type 3 ILCs. Consistent with the dual functions of IL-23 and IL-17 in mucosal immunity and inflammation, NIK deficiency also ameliorated colitis induction. Thus, our data suggest a pivotal role for the NIK signaling axis in regulating DC functions in intestinal immunity and homeostasis.
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Affiliation(s)
- Zuliang Jie
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jin-Young Yang
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Meidi Gu
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Hui Wang
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | - Xiaoping Xie
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yanchuan Li
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ting Liu
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Laboratory Medicine, West China Second University Hospital, State Key Laboratory of Biotherapy and Collaborative Innovation Center for Biotherapy, Sichuan University, Chengdu, China
| | - Lele Zhu
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jianhong Shi
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Central Laboratory, Affiliated Hospital of Hebei University, Baoding, China
| | - Lingyun Zhang
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Center for Reproductive Medicine, Henan Key Laboratory of Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaofei Zhou
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Donghyun Joo
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Hans D Brightbill
- Department of Immunology, Genentech, Inc., South San Francisco, CA, USA
| | - Yingzi Cong
- Department of Pathology and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Daniel Lin
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xuhong Cheng
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA.
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58
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Druzhinin VG, Matskova LV, Fucic A. Induction and modulation of genotoxicity by the bacteriome in mammals. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 776:70-77. [PMID: 29807578 DOI: 10.1016/j.mrrev.2018.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 04/19/2018] [Accepted: 04/20/2018] [Indexed: 02/07/2023]
Abstract
The living environment is a multilevel physical and chemical xenobiotic complex with potentially mutagenic effects and health risks. In addition to inorganic exposures, all terrestrial and aquatic living forms interact with microbiota as selectively established communities of bacteria, viruses and fungi. Along these lines, the human organism should then be considered a "meta-organism" with complex dynamics of interaction between the environment and microbiome. Bacterial communities within the microbiome, bacteriome, by its mass, symbiotic or competitive position and composition are in a fragile balance with the host organisms and have a crucial impact on their homeostasis. Bacteriome taxonomic composition is modulated by age, sex and host genetic profile and may be changed by adverse environmental exposures and life style factors such as diet or drug intake. A changed and/or misbalanced bacteriome has genotoxic potential with significant impact on the pathogenesis of acute, chronic and neoplastic diseases in the host organism. Bacteria may produce genotoxins, express a variety of pathways in which they generate free radicals or affect DNA repair causing genome damage, cell cycle arrest and apoptosis, modulate immune response and launch carcinogenesis in the host organism. Future investigations should focus on the interplay between exposure to xenobiotics and bacteriome composition, immunomodulation caused by misbalanced bacteriome, impact of the environment on bacteriome composition in children and its lifelong effect on health risks.
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Affiliation(s)
- V G Druzhinin
- Department of Genetics, Kemerovo State University, Kemerovo. Russia; Federal Research Center of Coal and Coal Chemistry of Siberian Branch of the Russian Academy of Sciences, Kemerovo, Russia
| | - L V Matskova
- Department of Microbiology and Tumor Biology, Karolinska Institute, Stockholm. Sweden
| | - A Fucic
- Institute for Medical Research and Occupational Health, Zagreb, Croatia.
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59
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Marlicz W, Skonieczna-Żydecka K, Dabos KJ, Łoniewski I, Koulaouzidis A. Emerging concepts in non-invasive monitoring of Crohn's disease. Therap Adv Gastroenterol 2018; 11:1756284818769076. [PMID: 29707039 PMCID: PMC5912292 DOI: 10.1177/1756284818769076] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Inflammatory bowel disease (IBD) is an umbrella term for Crohn's disease (CD) and ulcerative colitis (UC). In light of evolving epidemiology of CD, its clinical management is still complex and remains a challenge for contemporary physicians. With the advent of new diagnostic and treatment paradigms, there is a growing need for new biomarkers to guide decision-making, differential diagnosis, disease activity monitoring, as well as prognosis. However, both clinical and endoscopic scoring systems, widely utilized for disease monitoring and prognosis, have drawbacks and limitations. In recent years, biochemical peptides have become available for IBD monitoring and more frequently used as surrogate markers of gut inflammation. Emerging concepts that revolve around molecular, stem cell, epigenetic, microbial or metabolomic pathways associated with vascular and epithelial gut barrier could lead to development of new CD biomarkers. Measurement of cell-derived microvesicles (MVs) in the blood of IBD patients is another emerging concept helpful in future disease management. In this review, we discuss novel concepts of non-invasive biomarkers, which may become useful in monitoring of CD activity and prognosis. We discuss metabolomics as a new powerful tool for clinicians to guide differential IBD diagnosis. In the coming years, new developments of prognostic tools are expected, aiming for breakthroughs in the management of patients with CD.
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Affiliation(s)
- Wojciech Marlicz
- Department of Gastroenterology, Pomeranian Medical University, Unii Lubelskiej 1, 71-252 Szczecin, Poland
| | | | | | - Igor Łoniewski
- Department of Biochemistry and Human Nutrition, Pomeranian Medical University, Szczecin, Poland
- Sanprobi Sp. z o.o. Sp. K., Szczecin, Poland
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60
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Chronic stress promotes colitis by disturbing the gut microbiota and triggering immune system response. Proc Natl Acad Sci U S A 2018. [PMID: 29531080 DOI: 10.1073/pnas.1720696115] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chronic stress is known to promote inflammatory bowel disease (IBD), but the underlying mechanism remains largely unresolved. Here, we found chronic stress to sensitize mice to dextran sulfate sodium (DSS)-induced colitis; to increase the infiltration of B cells, neutrophils, and proinflammatory ly6Chi macrophages in colonic lamina propria; and to present with decreased thymus and mesenteric lymph node (MLN) coefficients. Circulating total white blood cells were significantly increased after stress, and the proportion of MLN-associated immune cells were largely changed. Results showed a marked activation of IL-6/STAT3 signaling by stress. The detrimental action of stress was not terminated in IL-6-/- mice. Interestingly, the composition of gut microbiota was dramatically changed after stress, with expansion of inflammation-promoting bacteria. Furthermore, results showed stress-induced deficient expression of mucin-2 and lysozyme, which may contribute to the disorder of gut microbiota. Of note is that, in the case of cohousing, the stress-induced immune reaction and decreased body weight were abrogated, and transferred gut microbiota from stressed mice to control mice was sufficient to facilitate DSS-induced colitis. The important role of gut microbiota was further reinforced by broad-spectrum antibiotic treatment. Taken together, our results reveal that chronic stress disturbs gut microbiota, triggering immune system response and facilitating DSS-induced colitis.
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61
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Alam R, Abdolmaleky HM, Zhou JR. Microbiome, inflammation, epigenetic alterations, and mental diseases. Am J Med Genet B Neuropsychiatr Genet 2017; 174:651-660. [PMID: 28691768 PMCID: PMC9586840 DOI: 10.1002/ajmg.b.32567] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/12/2017] [Indexed: 12/16/2022]
Abstract
Major mental diseases such as autism, bipolar disorder, schizophrenia, and major depressive disorder are debilitating illnesses with complex etiologies. Recent findings show that the onset and development of these illnesses cannot be well described by the one-gene; one-disease approach. Instead, their clinical presentation is thought to result from the regulative interplay of a large number of genes. Even though the involvement of many genes are likely, up regulating and activation or down regulation and silencing of these genes by the environmental factors play a crucial role in contributing to their pathogenesis. Much of this interplay may be moderated by epigenetic changes. Similar to genetic mutations, epigenetic modifications such as DNA methylation, histone modifications, and RNA interference can influence gene expression and therefore may cause behavioral and neuronal changes observed in mental disorders. Environmental factors such as diet, gut microbiota, and infections have significant role in these epigenetic modifications. Studies show that bioactive nutrients and gut microbiota can alter either DNA methylation and histone signatures through a variety of mechanisms. Indeed, microbes within the human gut may play a significant role in the regulation of various elements of "gut-brain axis," via their influence on inflammatory cytokines and production of antimicrobial peptides that affect the epigenome through their involvement in generating short chain fatty acids, vitamin synthesis, and nutrient absorption. In addition, they may participate in-gut production of many common neurotransmitters. In this review we will consider the potential interactions of diet, gastrointestinal microbiome, inflammation, and epigenetic alterations in psychiatric disorders.
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Affiliation(s)
- Reza Alam
- Nutrition/Metabolism Laboratory; Beth Israel Deaconess Medical Center; Harvard Medical School; Boston Massachusetts
| | - Hamid M. Abdolmaleky
- Nutrition/Metabolism Laboratory; Beth Israel Deaconess Medical Center; Harvard Medical School; Boston Massachusetts
| | - Jin-Rong Zhou
- Nutrition/Metabolism Laboratory; Beth Israel Deaconess Medical Center; Harvard Medical School; Boston Massachusetts
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