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Mihori S, Nichols F, Provatas A, Matz A, Zhou B, Blesso CN, Panier H, Daddi L, Zhou Y, Clark RB. Microbiome-derived bacterial lipids regulate gene expression of proinflammatory pathway inhibitors in systemic monocytes. Front Immunol 2024; 15:1415565. [PMID: 38989285 PMCID: PMC11233717 DOI: 10.3389/fimmu.2024.1415565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/29/2024] [Indexed: 07/12/2024] Open
Abstract
How the microbiome regulates responses of systemic innate immune cells is unclear. In the present study, our purpose was to document a novel mechanism by which the microbiome mediates crosstalk with the systemic innate immune system. We have identified a family of microbiome Bacteroidota-derived lipopeptides-the serine-glycine (S/G) lipids, which are TLR2 ligands, access the systemic circulation, and regulate proinflammatory responses of splenic monocytes. To document the role of these lipids in regulating systemic immunity, we used oral gavage with an antibiotic to decrease the production of these lipids and administered exogenously purified lipids to increase the systemic level of these lipids. We found that decreasing systemic S/G lipids by decreasing microbiome Bacteroidota significantly enhanced splenic monocyte proinflammatory responses. Replenishing systemic levels of S/G lipids via exogenous administration returned splenic monocyte responses to control levels. Transcriptomic analysis demonstrated that S/G lipids regulate monocyte proinflammatory responses at the level of gene expression of a small set of upstream inhibitors of TLR and NF-κB pathways that include Trem2 and Irf4. Consistent with enhancement in proinflammatory cytokine responses, decreasing S/G lipids lowered gene expression of specific pathway inhibitors. Replenishing S/G lipids normalized gene expression of these inhibitors. In conclusion, our results suggest that microbiome-derived S/G lipids normally establish a level of buffered signaling activation necessary for well-regulated innate immune responses in systemic monocytes. By regulating gene expression of inflammatory pathway inhibitors such as Trem2, S/G lipids merit broader investigation into the potential dysfunction of other innate immune cells, such as microglia, in diseases such as Alzheimer's disease.
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Affiliation(s)
- Saki Mihori
- Department of Immunology, UConn Health, Farmington, CT, United States
| | - Frank Nichols
- Department of Periodontology, UConn Health, Farmington, CT, United States
| | - Anthony Provatas
- Center for Environmental Sciences and Engineering, Institute of the Environment, University of Connecticut, Storrs, CT, United States
| | - Alyssa Matz
- Department of Immunology, UConn Health, Farmington, CT, United States
| | - Beiyan Zhou
- Department of Immunology, UConn Health, Farmington, CT, United States
| | - Christopher N. Blesso
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT, United States
| | - Hunter Panier
- Department of Medicine, UConn Health, Farmington, CT, United States
| | - Lauren Daddi
- Department of Medicine, UConn Health, Farmington, CT, United States
| | - Yanjiao Zhou
- Department of Medicine, UConn Health, Farmington, CT, United States
| | - Robert B. Clark
- Department of Immunology, UConn Health, Farmington, CT, United States
- Department of Medicine, UConn Health, Farmington, CT, United States
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Ekwudo MN, Gubert C, Hannan AJ. The microbiota-gut-brain axis in Huntington's disease: pathogenic mechanisms and therapeutic targets. FEBS J 2024. [PMID: 38426291 DOI: 10.1111/febs.17102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/08/2024] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
Huntington's disease (HD) is a currently incurable neurogenerative disorder and is typically characterized by progressive movement disorder (including chorea), cognitive deficits (culminating in dementia), psychiatric abnormalities (the most common of which is depression), and peripheral symptoms (including gastrointestinal dysfunction). There are currently no approved disease-modifying therapies available for HD, with death usually occurring approximately 10-25 years after onset, but some therapies hold promising potential. HD subjects are often burdened by chronic diarrhea, constipation, esophageal and gastric inflammation, and a susceptibility to diabetes. Our understanding of the microbiota-gut-brain axis in HD is in its infancy and growing evidence from preclinical and clinical studies suggests a role of gut microbial population imbalance (gut dysbiosis) in HD pathophysiology. The gut and the brain can communicate through the enteric nervous system, immune system, vagus nerve, and microbiota-derived-metabolites including short-chain fatty acids, bile acids, and branched-chain amino acids. This review summarizes supporting evidence demonstrating the alterations in bacterial and fungal composition that may be associated with HD. We focus on mechanisms through which gut dysbiosis may compromise brain and gut health, thus triggering neuroinflammatory responses, and further highlight outcomes of attempts to modulate the gut microbiota as promising therapeutic strategies for HD. Ultimately, we discuss the dearth of data and the need for more longitudinal and translational studies in this nascent field. We suggest future directions to improve our understanding of the association between gut microbes and the pathogenesis of HD, and other 'brain and body disorders'.
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Affiliation(s)
- Millicent N Ekwudo
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Carolina Gubert
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Australia
- Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
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Ma YY, Li X, Yu JT, Wang YJ. Therapeutics for neurodegenerative diseases by targeting the gut microbiome: from bench to bedside. Transl Neurodegener 2024; 13:12. [PMID: 38414054 PMCID: PMC10898075 DOI: 10.1186/s40035-024-00404-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/12/2024] [Indexed: 02/29/2024] Open
Abstract
The aetiologies and origins of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD), are complex and multifaceted. A growing body of evidence suggests that the gut microbiome plays crucial roles in the development and progression of neurodegenerative diseases. Clinicians have come to realize that therapeutics targeting the gut microbiome have the potential to halt the progression of neurodegenerative diseases. This narrative review examines the alterations in the gut microbiome in AD, PD, ALS and HD, highlighting the close relationship between the gut microbiome and the brain in neurodegenerative diseases. Processes that mediate the gut microbiome-brain communication in neurodegenerative diseases, including the immunological, vagus nerve and circulatory pathways, are evaluated. Furthermore, we summarize potential therapeutics for neurodegenerative diseases that modify the gut microbiome and its metabolites, including diets, probiotics and prebiotics, microbial metabolites, antibacterials and faecal microbiome transplantation. Finally, current challenges and future directions are discussed.
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Affiliation(s)
- Yuan-Yuan Ma
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042, China
- Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042, China
- Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042, China
| | - Xin Li
- Army 953 Hospital, Shigatse Branch of Xinqiao Hospital, Third Military Medical University, Shigatse, 857000, China
| | - Jin-Tai Yu
- Department of Neurology and National Center for Neurological Disorders, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, 200040, China.
| | - Yan-Jiang Wang
- Department of Neurology and Centre for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042, China.
- Institute of Brain and Intelligence, Third Military Medical University, Chongqing, 400042, China.
- Chongqing Key Laboratory of Ageing and Brain Diseases, Chongqing, 400042, China.
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Tarantino G, Citro V. What are the common downstream molecular events between alcoholic and nonalcoholic fatty liver? Lipids Health Dis 2024; 23:41. [PMID: 38331795 PMCID: PMC10851522 DOI: 10.1186/s12944-024-02031-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 01/25/2024] [Indexed: 02/10/2024] Open
Abstract
Liver fat storage, also called hepatic steatosis, is increasingly common and represents a very frequent diagnosis in the medical field. Excess fat is not without consequences. In fact, hepatic steatosis contributes to the progression toward liver fibrosis. There are two main types of fatty liver disease, alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). Although AFLD and NAFLD are similar in their initial morphological features, both conditions involve the same evolutive forms. Moreover, there are various common mechanisms underlying both diseases, including alcoholic liver disease and NAFLD, which are commonalities. In this Review, the authors explore similar downstream signaling events involved in the onset and progression of the two entities but not completely different entities, predominantly focusing on the gut microbiome. Downstream molecular events, such as the roles of sirtuins, cytokeratins, adipokines and others, should be considered. Finally, to complete the feature, some new tendencies in the therapeutic approach are presented.
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Affiliation(s)
| | - Vincenzo Citro
- Department of General Medicine, Umberto I Hospital, Nocera Inferiore, SA, 84014, Italy
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Kolypetri P, Weiner HL. Monocyte regulation by gut microbial signals. Trends Microbiol 2023; 31:1044-1057. [PMID: 37271658 PMCID: PMC10524398 DOI: 10.1016/j.tim.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 06/06/2023]
Abstract
Monocytes are innate immune cells that sense environmental changes and participate in the immunoregulation of autoimmune, neurologic, cardiovascular, and metabolic diseases as well as cancer. Recent studies have suggested that the gut microbiome shapes the biology of monocytes via microbial signals at extraintestinal sites. Interestingly, in chronic diseases, communication between microbial signals and monocytes can either promote or inhibit disease activity, suggesting that some of these pathways can be harnessed for clinical therapies. In this review, we discuss the newer concepts of regulation of monocyte homeostasis and function by gut microbial signals during steady state and inflammation. We also highlight the therapeutic potential of microbial signal-based approaches for modulation in the context of various diseases.
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Affiliation(s)
- Panayota Kolypetri
- Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Howard L Weiner
- Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Mandal RK, Schmidt NW. Mechanistic insights into the interaction between the host gut microbiome and malaria. PLoS Pathog 2023; 19:e1011665. [PMID: 37824458 PMCID: PMC10569623 DOI: 10.1371/journal.ppat.1011665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023] Open
Abstract
Malaria is a devastating infectious disease and significant global health burden caused by the bite of a Plasmodium-infected female Anopheles mosquito. Gut microbiota was recently discovered as a risk factor of severe malaria. This review entails the recent advances on the impact of gut microbiota composition on malaria severity and consequence of malaria infection on gut microbiota in mammalian hosts. Additionally, this review provides mechanistic insight into interactions that might occur between gut microbiota and host immunity which in turn can modulate malaria severity. Finally, approaches to modulate gut microbiota composition are discussed. We anticipate this review will facilitate novel hypotheses to move the malaria-gut microbiome field forward.
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Affiliation(s)
- Rabindra K. Mandal
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Herman B Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indiana, United States of America
| | - Nathan W. Schmidt
- Ryan White Center for Pediatric Infectious Diseases and Global Health, Herman B Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indiana, United States of America
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7
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Jordan CKI, Brown RL, Larkinson MLY, Sequeira RP, Edwards AM, Clarke TB. Symbiotic Firmicutes establish mutualism with the host via innate tolerance and resistance to control systemic immunity. Cell Host Microbe 2023; 31:1433-1449.e9. [PMID: 37582375 DOI: 10.1016/j.chom.2023.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/12/2023] [Accepted: 07/18/2023] [Indexed: 08/17/2023]
Abstract
The intestinal microbiota regulates immunity across organ systems. Which symbionts control systemic immunity, the mechanisms they use, and how they avoid widespread inflammatory damage are unclear. We uncover host tolerance and resistance mechanisms that allow Firmicutes from the human microbiota to control systemic immunity without inducing immunopathology. Intestinal processing releases Firmicute glycoconjugates that disseminate, resulting in release of cytokine IL-34 that stimulates macrophages and enhances defenses against pneumonia, sepsis, and meningitis. Despite systemic penetration of Firmicutes, immune homeostasis is maintained through feedback control whereby IL-34-mediated mTORC1 activation in macrophages clears polymeric glycoconjugates from peripheral tissues. Smaller glycoconjugates evading this clearance mechanism are tolerated through sequestration by albumin, which acts as an inflammatory buffer constraining their immunological impact. Without these resistance and tolerance mechanisms, Firmicutes drive catastrophic organ damage and cachexia via IL-1β. This reveals how Firmicutes are safely assimilated into systemic immunity to protect against infection without threatening host viability.
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Affiliation(s)
- Christine K I Jordan
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK
| | - Rebecca L Brown
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK
| | - Max L Y Larkinson
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK
| | - Richard P Sequeira
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK
| | - Andrew M Edwards
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK
| | - Thomas B Clarke
- Centre for Bacterial Resistance Biology, Department of Infectious Disease, Imperial College London, London SW7 2AZ, UK.
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Chauvin C, Alvarez-Simon D, Radulovic K, Boulard O, Laine W, Delacre M, Waldschmitt N, Segura E, Kluza J, Chamaillard M, Poulin LF. NOD2 in monocytes negatively regulates macrophage development through TNFalpha. Front Immunol 2023; 14:1181823. [PMID: 37415975 PMCID: PMC10320732 DOI: 10.3389/fimmu.2023.1181823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/23/2023] [Indexed: 07/08/2023] Open
Abstract
Objective It is believed that intestinal recruitment of monocytes from Crohn's Disease (CD) patients who carry NOD2 risk alleles may repeatedly give rise to recruitment of pathogenic macrophages. We investigated an alternative possibility that NOD2 may rather inhibit their differentiation from intravasating monocytes. Design The monocyte fate decision was examined by using germ-free mice, mixed bone marrow chimeras and a culture system yielding macrophages and monocyte-derived dendritic cells (mo-DCs). Results We observed a decrease in the frequency of mo-DCs in the colon of Nod2-deficient mice, despite a similar abundance of monocytes. This decrease was independent of the changes in the gut microbiota and dysbiosis caused by Nod2 deficiency. Similarly, the pool of mo-DCs was poorly reconstituted in a Nod2-deficient mixed bone marrow (BM) chimera. The use of pharmacological inhibitors revealed that activation of NOD2 during monocyte-derived cell development, dominantly inhibits mTOR-mediated macrophage differentiation in a TNFα-dependent manner. These observations were supported by the identification of a TNFα-dependent response to muramyl dipeptide (MDP) that is specifically lost when CD14-expressing blood cells bear a frameshift mutation in NOD2. Conclusion NOD2 negatively regulates a macrophage developmental program through a feed-forward loop that could be exploited for overcoming resistance to anti-TNF therapy in CD.
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Affiliation(s)
- Camille Chauvin
- U1019, Institut Pasteur de Lille, Univ. Lille, Centre National de la Recherche Scientifique, Inserm, Centre Hospitalo- Universitaire Lille, Lille, France
- INSERM U1138, Centre de Recherche des Cordeliers, Paris, France
| | - Daniel Alvarez-Simon
- U1019, Institut Pasteur de Lille, Univ. Lille, Centre National de la Recherche Scientifique, Inserm, Centre Hospitalo- Universitaire Lille, Lille, France
| | - Katarina Radulovic
- Unité de Recherche Clinique, Centre Hospitalier de Valenciennes, Valenciennes CEDEX, France
| | | | - William Laine
- UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, University Lille, Lille, France
| | - Myriam Delacre
- U1019, Institut Pasteur de Lille, Univ. Lille, Centre National de la Recherche Scientifique, Inserm, Centre Hospitalo- Universitaire Lille, Lille, France
| | - Nadine Waldschmitt
- Chair of Nutrition and Immunology, School of Life Sciences, Technische Universität München, Freising-Weihenstephan, Germany
| | - Elodie Segura
- INSERM U932, Institut Curie, Paris Sciences et Lettres Research University, Paris, France
| | - Jérome Kluza
- UMR9020-U1277 - CANTHER - Cancer Heterogeneity Plasticity and Resistance to Therapies, University Lille, Lille, France
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Long-distance relationships - regulation of systemic host defense against infections by the gut microbiota. Mucosal Immunol 2022; 15:809-818. [PMID: 35732817 DOI: 10.1038/s41385-022-00539-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/29/2022] [Accepted: 06/04/2022] [Indexed: 02/04/2023]
Abstract
Despite compartmentalization within the lumen of the gastrointestinal tract, the gut microbiota has a far-reaching influence on immune cell development and function throughout the body. This long-distance relationship is crucial for immune homeostasis, including effective host defense against invading pathogens that cause systemic infections. Herein, we review new insights into how commensal microbes that are spatially restricted to the gut lumen can engage in long-distance relationships with innate and adaptive immune cells at systemic sites to fortify host defenses against infections. In addition, we explore the consequences of intestinal dysbiosis on impaired host defense and immune-mediated pathology during infections, including emerging evidence linking dysbiosis with aberrant systemic inflammation and immune-mediated organ damage in sepsis. As such, therapeutic modification of the gut microbiota is an emerging target for interventions to prevent and/or treat systemic infections and sepsis by harnessing the long-distance relationships between gut microbes and systemic immunity.
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