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Simas AM, Kramer CD, Genco CA. Diet-Induced Non-alcoholic Fatty Liver Disease and Associated Gut Dysbiosis Are Exacerbated by Oral Infection. FRONTIERS IN ORAL HEALTH 2022; 2:784448. [PMID: 35141703 PMCID: PMC8820505 DOI: 10.3389/froh.2021.784448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/29/2021] [Indexed: 11/13/2022] Open
Abstract
Increasing evidence indicates that chronic inflammation due to periodontal disease is associated with progression of non-alcoholic fatty liver disease (NAFLD) caused by a Western diet. NAFLD has also been associated with oral infection with the etiological agent of periodontal disease, Porphyromonas gingivalis. P. gingivalis oral infection has been shown to induce cardiometabolic disease features including hepatic lipid accumulation while also leading to dysbiosis of the gut microbiome. However, the impact of P. gingivalis infection on the gut microbiota of mice with diet-induced NAFLD and the potential for those changes to mediate NAFLD progression has yet to be determined. In the current study, we have demonstrated that P. gingivalis infection induced sustained alterations of the gut microbiota composition and predicted functions, which was associated with the promotion of NAFLD in steatotic mice. Reduced abundance of short-chain fatty acid-producing microbiota was observed after both acute and chronic P. gingivalis infection. Collectively, our findings demonstrate that P. gingivalis infection produces a persistent change in the gut microbiota composition and predicted functions that promotes steatosis and metabolic disease.
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Affiliation(s)
- Alexandra M. Simas
- Gerald J. and Dorothy R. Friedman School of Nutrition and Science Policy, Graduate Program in Biochemical and Molecular Nutrition, Tufts University, Boston, MA, United States
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
| | - Carolyn D. Kramer
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
| | - Caroline A. Genco
- Department of Immunology, Tufts University School of Medicine, Boston, MA, United States
- Graduate Program in Immunology, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States
- Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States
- *Correspondence: Caroline A. Genco
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Diet, Gut Microbiota, and Colorectal Cancer Prevention: A Review of Potential Mechanisms and Promising Targets for Future Research. CURRENT COLORECTAL CANCER REPORTS 2017; 13:429-439. [PMID: 29333111 DOI: 10.1007/s11888-017-0389-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Diet plays an important role in the development of colorectal cancer. Emerging data have implicated the gut microbiota in colorectal cancer. Diet is a major determinant for the gut microbial structure and function. Therefore, it has been hypothesized that alterations in gut microbes and their metabolites may contribute to the influence of diet on the development of colorectal cancer. We review several major dietary factors that have been linked to gut microbiota and colorectal cancer, including major dietary patterns, fiber, red meat and sulfur, and obesity. Most of the epidemiologic evidence derives from cross-sectional or short-term, highly controlled feeding studies that are limited in size. Therefore, high-quality large-scale prospective studies with dietary data collected over the life course and comprehensive gut microbial composition and function assessed well prior to neoplastic occurrence are critically needed to identify microbiome-based interventions that may complement or optimize current diet-based strategies for colorectal cancer prevention and management.
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Kramer CD, Simas AM, He X, Ingalls RR, Weinberg EO, Genco CA. Distinct roles for dietary lipids and Porphyromonas gingivalis infection on atherosclerosis progression and the gut microbiota. Anaerobe 2017; 45:19-30. [PMID: 28442421 DOI: 10.1016/j.anaerobe.2017.04.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 02/08/2023]
Abstract
Mounting evidence in humans supports an etiological role for the microbiota in inflammatory atherosclerosis. Atherosclerosis is a progressive disease characterized by accumulation of inflammatory cells and lipids in vascular tissue. While retention of lipoprotein into the sub-endothelial vascular layer is believed to be the initiating stimulus leading to the development of atherosclerosis, activation of multiple pathways related to vascular inflammation and endothelial dysfunction sustain the process by stimulating recruitment of leukocytes and immune cells into the sub-endothelial layer. The Gram-negative oral pathogen Porphyromonas gingivalis has been associated with the development and acceleration of atherosclerosis in humans and these observations have been validated in animal models. It has been proposed that common mechanisms of immune signaling link stimulation by lipids and pathogens to vascular inflammation. Despite the common outcome of P. gingivalis and lipid feeding on atherosclerosis progression, we established that these pro-atherogenic stimuli induced distinct gene signatures in the ApoE-/- mouse model of atherosclerosis. In this study, we further defined the distinct roles of dietary lipids and P. gingivalis infection on atherosclerosis progression and the gut microbiota. We demonstrate that diet-induced lipid lowering resulted in less atherosclerotic plaque in ApoE-/- mice compared to ApoE-/- mice continuously fed a Western diet. However, the effect of diet-induced lipid lowering on plaque accumulation was blunted by P. gingivalis infection. Using principal component analysis and hierarchical clustering, we demonstrate that dietary intervention as well as P. gingivalis infection result in distinct bacterial communities in fecal and cecal samples of ApoE-/- mice as compared to ApoE-/- mice continuously fed either a Western diet or a normal chow diet. Collectively, we identified distinct microbiota changes accompanying atherosclerotic plaque, suggesting a future avenue for investigation on the impact of the gut microbiota, diet, and P. gingivalis infection on atherosclerosis.
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Affiliation(s)
- Carolyn D Kramer
- Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA; Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Ave, M & V 701, Boston, MA 02111, USA.
| | - Alexandra M Simas
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Ave, M & V 701, Boston, MA 02111, USA; Graduate Program in Biochemical and Molecular Nutrition, Gerald J. and Dorothy R. Friedman School of Nutrition and Science Policy, Tufts University, Boston, MA 02111, USA.
| | - Xianbao He
- Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA; Boston Medical Center, Evans Biomedical Research Center, 650 Albany Street, Boston, MA 02118, USA.
| | - Robin R Ingalls
- Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA; Boston Medical Center, Evans Biomedical Research Center, 650 Albany Street, Boston, MA 02118, USA.
| | - Ellen O Weinberg
- Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA; Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Ave, M & V 701, Boston, MA 02111, USA.
| | - Caroline Attardo Genco
- Department of Medicine, Section of Infectious Diseases, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA; Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, 136 Harrison Ave, M & V 701, Boston, MA 02111, USA; Graduate Program in Immunology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Ave, M & V 701, Boston, MA 02111, USA; Graduate Program in Microbiology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Ave, M & V 701, Boston, MA 02111, USA.
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Shaik-Dasthagirisaheb YB, Mekasha S, He X, Gibson FC, Ingalls RR. Signaling events in pathogen-induced macrophage foam cell formation. Pathog Dis 2016; 74:ftw074. [PMID: 27481727 DOI: 10.1093/femspd/ftw074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2016] [Indexed: 12/31/2022] Open
Abstract
Macrophage foam cell formation is a key event in atherosclerosis. Several triggers induce low-density lipoprotein (LDL) uptake by macrophages to create foam cells, including infections with Porphyromonas gingivalis and Chlamydia pneumoniae, two pathogens that have been linked to atherosclerosis. While gene regulation during foam cell formation has been examined, comparative investigations to identify shared and specific pathogen-elicited molecular events relevant to foam cell formation are not well documented. We infected mouse bone marrow-derived macrophages with P. gingivalis or C. pneumoniae in the presence of LDL to induce foam cell formation, and examined gene expression using an atherosclerosis pathway targeted plate array. We found over 30 genes were significantly induced in response to both pathogens, including PPAR family members that are broadly important in atherosclerosis and matrix remodeling genes that may play a role in plaque development and stability. Six genes mainly involved in lipid transport were significantly downregulated. The response overall was remarkably similar and few genes were regulated in a pathogen-specific manner. Despite very divergent lifestyles, P. gingivalis and C. pneumoniae activate similar gene expression profiles during foam cell formation that may ultimately serve as targets for modulating infection-elicited foam cell burden, and progression of atherosclerosis.
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Affiliation(s)
- Yazdani B Shaik-Dasthagirisaheb
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA
| | - Samrawit Mekasha
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA
| | - Xianbao He
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA
| | - Frank C Gibson
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA
| | - Robin R Ingalls
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA 02118, USA
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Slocum C, Kramer C, Genco CA. Immune dysregulation mediated by the oral microbiome: potential link to chronic inflammation and atherosclerosis. J Intern Med 2016; 280:114-28. [PMID: 26791914 DOI: 10.1111/joim.12476] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cardiovascular disease is an inflammatory disorder characterized by the progressive formation of plaque in coronary arteries, termed atherosclerosis. It is a multifactorial disease that is one of the leading causes of death worldwide. Although a number of risk factors have been associated with disease progression, the underlying inflammatory mechanisms contributing to atherosclerosis remain to be fully delineated. Within the last decade, the potential role for infection in inflammatory plaque progression has received considerable interest. Microbial pathogens associated with periodontal disease have been of particular interest due to the high levels of bacteremia that are observed after routine dental procedures and every day oral activities, such as tooth brushing. Here, we explore the potential mechanisms that may explain how periodontal pathogens either directly or indirectly elicit immune dysregulation and consequently progressive inflammation manifested as atherosclerosis. Periodontal pathogens have been shown to contribute directly to atherosclerosis by disrupting endothelial cell function, one of the earliest indicators of cardiovascular disease. Oral infection is thought to indirectly induce elevated production of inflammatory mediators in the systemic circulation. Recently, a number of studies have been conducted focusing on how disruption of the gut microbiome influences the systemic production of proinflammatory cytokines and consequently exacerbation of inflammatory diseases such as atherosclerosis. It is clear that the immune mechanisms leading to atherosclerotic plaque progression, by oral infection, are complex. Understanding the immune pathways leading to disease progression is essential for the future development of anti-inflammatory therapies for this chronic disease.
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Affiliation(s)
| | - C Kramer
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, MA, USA
| | - C A Genco
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, MA, USA
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Specific Inflammatory Stimuli Lead to Distinct Platelet Responses in Mice and Humans. PLoS One 2015; 10:e0131688. [PMID: 26148065 PMCID: PMC4493099 DOI: 10.1371/journal.pone.0131688] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 06/05/2015] [Indexed: 01/08/2023] Open
Abstract
Introduction Diverse and multi-factorial processes contribute to the progression of cardiovascular disease. These processes affect cells involved in the development of this disease in varying ways, ultimately leading to atherothrombosis. The goal of our study was to compare the differential effects of specific stimuli – two bacterial infections and a Western diet – on platelet responses in ApoE-/- mice, specifically examining inflammatory function and gene expression. Results from murine studies were verified using platelets from participants of the Framingham Heart Study (FHS; n = 1819 participants). Methods Blood and spleen samples were collected at weeks 1 and 9 from ApoE-/- mice infected with Porphyromonas gingivalis or Chlamydia pneumoniae and from mice fed a Western diet for 9 weeks. Transcripts based on data from a Western diet in ApoE-/- mice were measured in platelet samples from FHS using high throughput qRT-PCR. Results At week 1, both bacterial infections increased circulating platelet-neutrophil aggregates. At week 9, these cells individually localized to the spleen, while Western diet resulted in increased platelet-neutrophil aggregates in the spleen only. Microarray analysis of platelet RNA from infected or Western diet-fed mice at week 1 and 9 showed differential profiles. Genes, such as Serpina1a, Ttr, Fgg, Rpl21, and Alb, were uniquely affected by infection and diet. Results were reinforced in platelets obtained from participants of the FHS. Conclusion Using both human studies and animal models, results demonstrate that variable sources of inflammatory stimuli have the ability to influence the platelet phenotype in distinct ways, indicative of the diverse function of platelets in thrombosis, hemostasis, and immunity.
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Campbell LA, Rosenfeld ME. Infection and Atherosclerosis Development. Arch Med Res 2015; 46:339-50. [PMID: 26004263 PMCID: PMC4524506 DOI: 10.1016/j.arcmed.2015.05.006] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 05/12/2015] [Indexed: 01/19/2023]
Abstract
Atherosclerosis is a chronic disease hallmarked by chronic inflammation, endothelial dysfunction and lipid accumulation in the vasculature. Although lipid modification and deposition are thought to be a major source of the continuous inflammatory stimulus, a large body of evidence suggests that infectious agents may contribute to atherosclerotic processes. This could occur by either direct effects through infection of vascular cells and/or through indirect effects by induction of cytokine and acute phase reactant proteins by infection at other sites. Multiple bacterial and viral pathogens have been associated with atherosclerosis by seroepidemiological studies, identification of the infectious agent in human atherosclerotic tissue, and experimental studies demonstrating an acceleration of atherosclerosis following infection in animal models of atherosclerosis. This review will focus on those infectious agents for which biological plausibility has been demonstrated in animal models and on the challenges of proving a role of infection in human atherosclerotic disease.
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Affiliation(s)
- Lee Ann Campbell
- Department of Epidemiology, School of Public Health, Seattle, Washington, USA.
| | - Michael E Rosenfeld
- Departments of Environmental, Health and Occupational Sciences and Pathology, University of Washington, Seattle, Washington, USA
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