1
|
Delgado-Ocaña S, Cuesta S. From microbes to mind: germ-free models in neuropsychiatric research. mBio 2024:e0207524. [PMID: 39207144 DOI: 10.1128/mbio.02075-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
The gut-microbiota-brain axis refers to the bidirectional communication system between the gut, its microbial community, and the brain. This interaction involves a complex interplay of neural pathways, chemical transmitters, and immunological mechanisms. Germ-free animal models have been extensively employed to investigate gut-microbiota-brain interactions, significantly contributing to our current understanding of the role of intestinal microbes in brain function. However, despite the many benefits, this absence of microbiota is not futile. Germ-free animals present physiological and neurodevelopmental alterations that can persist even after reconstitution with normal microbiota. Therefore, the main goal of this minireview is to discuss how some of the inherent limitations of this model can interfere with the conclusion obtained when using these animals to study the complex nature of neuropsychiatric disorders. Furthermore, we examine the inclusion and use of antibiotic-based treatments as an alternative in the research of gut-brain interactions.
Collapse
Affiliation(s)
- Susana Delgado-Ocaña
- Department of Cell Biology and Neuroscience, Rutgers the State University of New Jersey, Piscataway, New Jersey, USA
| | - Santiago Cuesta
- Department of Cell Biology and Neuroscience, Rutgers the State University of New Jersey, Piscataway, New Jersey, USA
| |
Collapse
|
2
|
Tannock GW. Gnotobiotic experimentation helps define symbiogenesis in vertebrate evolution. NEW ZEALAND JOURNAL OF ZOOLOGY 2023. [DOI: 10.1080/03014223.2023.2169943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Affiliation(s)
- Gerald W. Tannock
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| |
Collapse
|
3
|
Rasmussen N. René Dubos, the Autochthonous Flora, and the Discovery of the Microbiome. JOURNAL OF THE HISTORY OF BIOLOGY 2022; 55:537-558. [PMID: 36348188 PMCID: PMC9668787 DOI: 10.1007/s10739-022-09692-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
Now characterised by high-throughput sequencing methods that enable the study of microbes without lab culture, the human "microbiome" (the microbial flora of the body) is said to have revolutionary implications for biology and medicine. According to many experts, we must now understand ourselves as "holobionts" like lichen or coral, multispecies superorganisms that consist of animal and symbiotic microbes in combination, because normal physiological function depends on them. Here I explore the 1960s research of biologist René Dubos, a forerunner figure mentioned in some historical accounts of the microbiome, and argue that he arrived at the superorganism concept 40 years before the Human Microbiome Project. This raises the question of why his contribution was not hailed as revolutionary at the time and why Dubos is not remembered for it.
Collapse
Affiliation(s)
- Nicolas Rasmussen
- School of Humanities, University of New South Wales, NSW 2052, Sydney, Australia.
| |
Collapse
|
4
|
Houtz JL, Taff CC, Vitousek MN. Gut Microbiome as a Mediator of Stress Resilience: A Reactive Scope Model Framework. Integr Comp Biol 2022; 62:41-57. [PMID: 35544275 DOI: 10.1093/icb/icac030] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stress resilience is defined as the ability to rebound to a homeostatic state after exposure to a perturbation. Organisms modulate various physiological mediators to respond to unpredictable changes in their environment. The gut microbiome is a key example of a physiological mediator that coordinates a myriad of host functions including counteracting stressors. Here, we highlight the gut microbiome as a mediator of host stress resilience in the framework of the reactive scope model. The reactive scope model integrates physiological mediators with unpredictable environmental changes to predict how animals respond to stressors. We provide examples of how the gut microbiome responds to stressors within the four ranges of the reactive scope model (i.e., predictive homeostasis, reactive homeostasis, homeostatic overload, and homeostatic failure). We identify measurable metrics of the gut microbiome that could be used to infer the degree to which the host is experiencing chronic stress, including microbial diversity, flexibility, and gene richness. The goal of this perspective piece is to highlight the underutilized potential of measuring the gut microbiome as a mediator of stress resilience in wild animal hosts.
Collapse
Affiliation(s)
- Jennifer L Houtz
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Conor C Taff
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
5
|
Boussamet L, Rajoka MSR, Berthelot L. Microbiota, IgA and Multiple Sclerosis. Microorganisms 2022; 10:microorganisms10030617. [PMID: 35336190 PMCID: PMC8954136 DOI: 10.3390/microorganisms10030617] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 12/16/2022] Open
Abstract
Multiple sclerosis (MS) is a neuroinflammatory disease characterized by immune cell infiltration in the central nervous system and destruction of myelin sheaths. Alterations of gut bacteria abundances are present in MS patients. In mouse models of neuroinflammation, depletion of microbiota results in amelioration of symptoms, and gavage with MS patient microbiota exacerbates the disease and inflammation via Th17 cells. On the other hand, depletion of B cells using anti-CD20 is an efficient therapy in MS, and growing evidence shows an important deleterious role of B cells in MS pathology. However, the failure of TACI-Ig treatment in MS highlighted the potential regulatory role of plasma cells. The mechanism was recently demonstrated involving IgA+ plasma cells, specific for gut microbiota and producing IL-10. IgA-coated bacteria in MS patient gut exhibit also modifications. We will focus our review on IgA interactions with gut microbiota and IgA+ B cells in MS. These recent data emphasize new pathways of neuroinflammation regulation in MS.
Collapse
Affiliation(s)
- Léo Boussamet
- Centre for Research in Transplantation and Translation Immunology, Nantes Université, Inserm, CR2TI UMR, 1064 Nantes, France;
| | - Muhammad Shahid Riaz Rajoka
- Laboratory of Animal Food Function, Graduate School of Agricultural Science, Tohoku University, Sendai 980-8572, Japan;
| | - Laureline Berthelot
- Centre for Research in Transplantation and Translation Immunology, Nantes Université, Inserm, CR2TI UMR, 1064 Nantes, France;
- Correspondence:
| |
Collapse
|
6
|
Lawson MAE, Roberts IS, Grencis RK. The interplay between Trichuris and the microbiota. Parasitology 2021; 148:1-8. [PMID: 34075861 PMCID: PMC8660641 DOI: 10.1017/s0031182021000834] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/17/2021] [Accepted: 05/20/2021] [Indexed: 11/30/2022]
Abstract
Parasitic worms are amongst the most common pathogens to infect humans and have a long-established history of inflicting disease in their hosts. There is a large body of evidence that states intestine-dwelling helminths ensure their survival by influencing the host immune response against them. In recent years, it has become apparent that the large and diverse microbial communities that exist in the gastrointestinal (GI) tract of the host and within the parasite itself have a pivotal role in worm survival and persistence. Using a variety of mouse models (including laboratory, germ-free and rewilded mice), there have been new insights into how bacteria and worms interact with each other; this includes the discovery that Trichuris is unable to hatch and/or infect their host in the absence of bacteria, and that these worms contain a Trichuris-specific gut microbiota. These interactions are determined in part by the capacity of the host, gut microbiota and worms to communicate via metabolites such as butyrate, which are microbially derived and have known immunoregulatory properties. By exploring the contribution of gut bacteria to worm infections and the intricate relationship that exists between them, an exciting and emerging field in whipworm parasitology is established.
Collapse
Affiliation(s)
- Melissa A. E. Lawson
- Lydia Becker Institute for Immunology and Inflammation, Manchester, M13 9PT, UK
- Wellcome Trust Centre for Cell Matrix Research, Manchester, M13 9PT, UK
- Division of Infection, Immunity and Respiratory Medicine, Manchester, M13 9PT, UK
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PL, UK
| | - Ian S. Roberts
- Lydia Becker Institute for Immunology and Inflammation, Manchester, M13 9PT, UK
- Division of Infection, Immunity and Respiratory Medicine, Manchester, M13 9PT, UK
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PL, UK
| | - Richard K. Grencis
- Lydia Becker Institute for Immunology and Inflammation, Manchester, M13 9PT, UK
- Wellcome Trust Centre for Cell Matrix Research, Manchester, M13 9PT, UK
- Division of Infection, Immunity and Respiratory Medicine, Manchester, M13 9PT, UK
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PL, UK
| |
Collapse
|
7
|
Rudzki L, Stone TW, Maes M, Misiak B, Samochowiec J, Szulc A. Gut microbiota-derived vitamins - underrated powers of a multipotent ally in psychiatric health and disease. Prog Neuropsychopharmacol Biol Psychiatry 2021; 107:110240. [PMID: 33428888 DOI: 10.1016/j.pnpbp.2020.110240] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/19/2020] [Accepted: 12/30/2020] [Indexed: 02/06/2023]
Abstract
Despite the well-established roles of B-vitamins and their deficiencies in health and disease, there is growing evidence indicating a key role of those nutrients in functions of the central nervous system and in psychopathology. Clinical data indicate the substantial role of B-vitamins in various psychiatric disorders, including major depression, bipolar disorder, schizophrenia, autism, and dementia, including Alzheimer's and Parkinson's diseases. As enzymatic cofactors, B-vitamins are involved in many physiological processes such as the metabolism of glucose, fatty acids and amino acids, metabolism of tryptophan in the kynurenine pathway, homocysteine metabolism, synthesis and metabolism of various neurotransmitters and neurohormones including serotonin, dopamine, adrenaline, acetylcholine, GABA, glutamate, D-serine, glycine, histamine and melatonin. Those vitamins are highly involved in brain energetic metabolism and respiration at the cellular level. They have a broad range of anti-inflammatory, immunomodulatory, antioxidant and neuroprotective properties. Furthermore, some of those vitamins are involved in the regulation of permeability of the intestinal and blood-brain barriers. Despite the fact that a substantial amount of the above vitamins is acquired from various dietary sources, deficiencies are not uncommon, and it is estimated that micronutrient deficiencies affect about two billion people worldwide. The majority of gut-resident microbes and the broad range of bacteria available in fermented food, express genetic machinery enabling the synthesis and metabolism of B-vitamins and, consequently, intestinal microbiota and fermented food rich in probiotic bacteria are essential sources of B-vitamins for humans. All in all, there is growing evidence that intestinal bacteria-derived vitamins play a significant role in physiology and that dysregulation of the "microbiota-vitamins frontier" is related to various disorders. In this review, we will discuss the role of vitamins in mental health and explore the perspectives and potential of how gut microbiota-derived vitamins could contribute to mental health and psychiatric treatment.
Collapse
Affiliation(s)
- Leszek Rudzki
- The Charleston Centre, 49 Neilston Road, Paisley PA2 6LY, UK.
| | | | - Michael Maes
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Department of Psychiatry, Medical University of Plovdiv, Bulgaria; IMPACT Strategic Research Center, Deakin University, Geelong, Australia
| | - Błażej Misiak
- Department of Psychiatry, Wroclaw Medical University, Pasteura 10 Street, 50-367 Wroclaw, Poland
| | - Jerzy Samochowiec
- Department of Psychiatry, Pomeranian Medical University, Broniewskiego 26 Street, 71-460 Szczecin, Poland
| | - Agata Szulc
- Department of Psychiatry, Medical University of Warsaw, Poland
| |
Collapse
|
8
|
Romoli O, Schönbeck JC, Hapfelmeier S, Gendrin M. Production of germ-free mosquitoes via transient colonisation allows stage-specific investigation of host-microbiota interactions. Nat Commun 2021; 12:942. [PMID: 33574256 PMCID: PMC7878806 DOI: 10.1038/s41467-021-21195-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 01/15/2021] [Indexed: 02/07/2023] Open
Abstract
The mosquito microbiota impacts the physiology of its host and is essential for normal larval development, thereby influencing transmission of vector-borne pathogens. Germ-free mosquitoes generated with current methods show larval stunting and developmental deficits. Therefore, functional studies of the mosquito microbiota have so far mostly been limited to antibiotic treatments of emerging adults. In this study, we introduce a method to produce germ-free Aedes aegypti mosquitoes. It is based on reversible colonisation with bacteria genetically modified to allow complete decolonisation at any developmental stage. We show that, unlike germ-free mosquitoes previously produced using sterile diets, reversibly colonised mosquitoes show no developmental retardation and reach the same size as control adults. This allows us to uncouple the study of the microbiota in larvae and adults. In adults, we detect no impact of bacterial colonisation on mosquito fecundity or longevity. In larvae, data from our transcriptome analysis and diet supplementation experiments following decolonisation suggest that bacteria support larval development by contributing to folate biosynthesis and by enhancing energy storage. Our study establishes a tool to study the microbiota in insects and deepens our knowledge on the metabolic contribution of bacteria to mosquito development.
Collapse
Affiliation(s)
- Ottavia Romoli
- grid.418525.f0000 0001 2206 8813Microbiota of Insect Vectors Group, Institut Pasteur de la Guyane, Cayenne, French Guiana France
| | - Johan Claes Schönbeck
- grid.418525.f0000 0001 2206 8813Microbiota of Insect Vectors Group, Institut Pasteur de la Guyane, Cayenne, French Guiana France
| | - Siegfried Hapfelmeier
- grid.5734.50000 0001 0726 5157Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Mathilde Gendrin
- grid.418525.f0000 0001 2206 8813Microbiota of Insect Vectors Group, Institut Pasteur de la Guyane, Cayenne, French Guiana France ,grid.428999.70000 0001 2353 6535Parasites and Insect Vectors Department, Institut Pasteur, Paris, France
| |
Collapse
|
9
|
Al-Khafaji AH, Jepsen SD, Christensen KR, Vigsnæs LK. The potential of human milk oligosaccharides to impact the microbiota-gut-brain axis through modulation of the gut microbiota. J Funct Foods 2020. [DOI: 10.1016/j.jff.2020.104176] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
10
|
Qv L, Yang Z, Yao M, Mao S, Li Y, Zhang J, Li L. Methods for Establishment and Maintenance of Germ-Free Rat Models. Front Microbiol 2020; 11:1148. [PMID: 32670216 PMCID: PMC7326071 DOI: 10.3389/fmicb.2020.01148] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/06/2020] [Indexed: 12/11/2022] Open
Abstract
Numerous studies have demonstrated that the gut microbiota plays a vital role in human health and disease development. Although the number of studies on host–microbiota interactions have increased in recent years, the underlying pathogenesis of dysbiosis-related diseases are still largely unknown. Germ-free (GF) rodent models, with the animals housed in sterile isolators and completely free of microbiota, are useful tools to advance our understanding of host–microbiota relationship in vivo. Although protocols concerning the establishment and maintenance of GF mouse models have previously been reported, the establishment, maintenance and monitoring of GF rodents are labor-intensive, tedious and take experience and skills. The aim of our study was to establish a GF rat model for the following microbiota-related researches and provide an easy-to-use protocol for the establishment and maintenance of GF rat model in detail, including steps to set up the isolator, sterilize the flexible isolator bubble, import food, water and other supplies, and methods to acquire newborn GF rats, hand rearing of suckling GF rats and reproduction of GF offspring. During the hand feeding period, the body weight of suckling GF rats was weighed once a day to ascertain the amount of artificial milk was given. Based on our results, the body weight of suckling GF rats decreased 1 week after birth and then began to increase. Methods for verifying the quality of the model like assessing the sterile status of the rat colony are also described. Moreover, possible difficulties and challenges, especially during gavage, and suggestions to avoid contamination will be discussed. The protocol presented will facilitate the establishment of GF rat models and downstream microbiota-related researches.
Collapse
Affiliation(s)
- Lingling Qv
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Zhenggang Yang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Mingfei Yao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Sunbing Mao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yongjun Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Jia Zhang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| |
Collapse
|
11
|
Carter PB, Norin E, Swennes AG. Gnotobiotics and the Microbiome. THE LABORATORY RAT 2020. [PMCID: PMC7158190 DOI: 10.1016/b978-0-12-814338-4.00021-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This chapter provides an overview of germfree (GF), gnotobiotic (GN), and defined flora (DF) laboratory rats, relating their history, traditional and modern derivation procedures, the anatomy and physiology, and their use in the study of mammalian host–microbiome relationships. Extensive literature on the nutrition and physiology of GF rats and the expanding library of immunological reagents have increased the research utility of GF, GN, or DF rats. Such rats have been extensively used in metabolic experiments as nucleus seed stocks for the production of disease-free animals and as tools for infectious disease studies, among others. The chapter also presents research applications of GF rats that are particularly suitable for testing candidate viral carcinogens since they are uniquely free of all known viruses, for pathology studies in the distinguishing of primary mediation lesions from those associated with infections, and the study of the biological effects of radiation.
Collapse
|
12
|
Romano KA, Rey FE. Is maternal microbial metabolism an early-life determinant of health? Lab Anim (NY) 2018; 47:239-243. [PMID: 30143761 DOI: 10.1038/s41684-018-0129-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 07/25/2018] [Indexed: 12/31/2022]
Abstract
Mounting evidence suggests that environmental stress experienced in utero (for example, maternal nutritional deficits) establishes a predisposition in the newborn to the development of chronic diseases later in life. This concept is often referred to as the "fetal origins hypothesis" or "developmental origins of health and disease". Since its first proposal, epigenetics has emerged as an underlying mechanism explaining how environmental cues become gestationally "encoded". Many of the enzymes that impart and maintain epigenetic modifications are highly sensitive to nutrient availability, which can be influenced by the metabolic activities of the intestinal microbiota. Therefore, the maternal microbiome has the potential to influence epigenetics in utero and modulate offspring's long-term health trajectories. Here we summarize the current understanding of the interactions that occur between the maternal gut microbiome and the essential nutrient choline, that is not only required for fetal development and epigenetic regulation but is also a growth substrate for some microbes. Bacteria able to metabolize choline benefit from the presence of this nutrient and compete with the host for its access, which under extreme conditions may elicit signatures of choline deficiency. Another consequence of bacterial choline metabolism is the accumulation of the pro-inflammatory, pro-thrombotic metabolite trimethylamine-N-oxide (TMAO). Finally, we discuss how these different facets of microbial choline metabolism may influence infant development and health trajectories via epigenetic mechanisms and more broadly place a call to action to better understand how maternal microbial metabolism can shape their offspring's propensity to chronic disease development later in life.
Collapse
Affiliation(s)
| | - Federico E Rey
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
13
|
Kenny DJ, Balskus EP. Engineering chemical interactions in microbial communities. Chem Soc Rev 2018; 47:1705-1729. [PMID: 29210396 DOI: 10.1039/c7cs00664k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Microbes living within host-associated microbial communities (microbiotas) rely on chemical communication to interact with surrounding organisms. These interactions serve many purposes, from supplying the multicellular host with nutrients to antagonizing invading pathogens, and breakdown of chemical signaling has potentially negative consequences for both the host and microbiota. Efforts to engineer microbes to take part in chemical interactions represent a promising strategy for modulating chemical signaling within these complex communities. In this review, we discuss prominent examples of chemical interactions found within host-associated microbial communities, with an emphasis on the plant-root microbiota and the intestinal microbiota of animals. We then highlight how an understanding of such interactions has guided efforts to engineer microbes to participate in chemical signaling in these habitats. We discuss engineering efforts in the context of chemical interactions that enable host colonization, promote host health, and exclude pathogens. Finally, we describe prominent challenges facing this field and propose new directions for future engineering efforts.
Collapse
Affiliation(s)
- Douglas J Kenny
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
| | | |
Collapse
|
14
|
Luczynski P, McVey Neufeld KA, Oriach CS, Clarke G, Dinan TG, Cryan JF. Growing up in a Bubble: Using Germ-Free Animals to Assess the Influence of the Gut Microbiota on Brain and Behavior. Int J Neuropsychopharmacol 2016; 19:pyw020. [PMID: 26912607 PMCID: PMC5006193 DOI: 10.1093/ijnp/pyw020] [Citation(s) in RCA: 356] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 02/18/2016] [Indexed: 12/13/2022] Open
Abstract
There is a growing recognition of the importance of the commensal intestinal microbiota in the development and later function of the central nervous system. Research using germ-free mice (mice raised without any exposure to microorganisms) has provided some of the most persuasive evidence for a role of these bacteria in gut-brain signalling. Key findings show that the microbiota is necessary for normal stress responsivity, anxiety-like behaviors, sociability, and cognition. Furthermore, the microbiota maintains central nervous system homeostasis by regulating immune function and blood brain barrier integrity. Studies have also found that the gut microbiota influences neurotransmitter, synaptic, and neurotrophic signalling systems and neurogenesis. The principle advantage of the germ-free mouse model is in proof-of-principle studies and that a complete microbiota or defined consortiums of bacteria can be introduced at various developmental time points. However, a germ-free upbringing can induce permanent neurodevelopmental deficits that may deem the model unsuitable for specific scientific queries that do not involve early-life microbial deficiency. As such, alternatives and complementary strategies to the germ-free model are warranted and include antibiotic treatment to create microbiota-deficient animals at distinct time points across the lifespan. Increasing our understanding of the impact of the gut microbiota on brain and behavior has the potential to inform novel management strategies for stress-related gastrointestinal and neuropsychiatric disorders.
Collapse
Affiliation(s)
- Pauline Luczynski
- APC Microbiome Institute (Ms Luczynski, Dr McVey Neufeld, Ms Oriach, Dr Clarke, Dr Dinan, and Dr Cryan), Department of Psychiatry and Neurobehavioral Science (Ms Oriach, Dr Clarke, and Dr Dinan), and Department of Anatomy and Neuroscience (Dr Cryan), University College Cork, Cork, Ireland
| | - Karen-Anne McVey Neufeld
- APC Microbiome Institute (Ms Luczynski, Dr McVey Neufeld, Ms Oriach, Dr Clarke, Dr Dinan, and Dr Cryan), Department of Psychiatry and Neurobehavioral Science (Ms Oriach, Dr Clarke, and Dr Dinan), and Department of Anatomy and Neuroscience (Dr Cryan), University College Cork, Cork, Ireland
| | - Clara Seira Oriach
- APC Microbiome Institute (Ms Luczynski, Dr McVey Neufeld, Ms Oriach, Dr Clarke, Dr Dinan, and Dr Cryan), Department of Psychiatry and Neurobehavioral Science (Ms Oriach, Dr Clarke, and Dr Dinan), and Department of Anatomy and Neuroscience (Dr Cryan), University College Cork, Cork, Ireland
| | - Gerard Clarke
- APC Microbiome Institute (Ms Luczynski, Dr McVey Neufeld, Ms Oriach, Dr Clarke, Dr Dinan, and Dr Cryan), Department of Psychiatry and Neurobehavioral Science (Ms Oriach, Dr Clarke, and Dr Dinan), and Department of Anatomy and Neuroscience (Dr Cryan), University College Cork, Cork, Ireland
| | - Timothy G Dinan
- APC Microbiome Institute (Ms Luczynski, Dr McVey Neufeld, Ms Oriach, Dr Clarke, Dr Dinan, and Dr Cryan), Department of Psychiatry and Neurobehavioral Science (Ms Oriach, Dr Clarke, and Dr Dinan), and Department of Anatomy and Neuroscience (Dr Cryan), University College Cork, Cork, Ireland
| | - John F Cryan
- APC Microbiome Institute (Ms Luczynski, Dr McVey Neufeld, Ms Oriach, Dr Clarke, Dr Dinan, and Dr Cryan), Department of Psychiatry and Neurobehavioral Science (Ms Oriach, Dr Clarke, and Dr Dinan), and Department of Anatomy and Neuroscience (Dr Cryan), University College Cork, Cork, Ireland.
| |
Collapse
|
15
|
Ghaisas S, Maher J, Kanthasamy A. Gut microbiome in health and disease: Linking the microbiome-gut-brain axis and environmental factors in the pathogenesis of systemic and neurodegenerative diseases. Pharmacol Ther 2015; 158:52-62. [PMID: 26627987 DOI: 10.1016/j.pharmthera.2015.11.012] [Citation(s) in RCA: 329] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The gut microbiome comprises the collective genome of the trillions of microorganisms residing in our gastrointestinal ecosystem. The interaction between the host and its gut microbiome is a complex relationship whose manipulation could prove critical to preventing or treating not only various gut disorders, like irritable bowel syndrome (IBS) and ulcerative colitis (UC), but also central nervous system (CNS) disorders, such as Alzheimer's and Parkinson's diseases. The purpose of this review is to summarize what is known about the gut microbiome, how it is connected to the development of disease and to identify the bacterial and biochemical targets that should be the focus of future research. Understanding the mechanisms behind the activity and proliferation of the gut microbiome will provide us new insights that may pave the way for novel therapeutic strategies.
Collapse
Affiliation(s)
- Shivani Ghaisas
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Joshua Maher
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Anumantha Kanthasamy
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA.
| |
Collapse
|
16
|
Barcoded pyrosequencing-based metagenomic analysis of the faecal microbiome of three purebred pig lines after cohabitation. Appl Microbiol Biotechnol 2015; 99:5647-56. [PMID: 25652653 DOI: 10.1007/s00253-015-6408-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 01/13/2015] [Accepted: 01/15/2015] [Indexed: 01/11/2023]
Abstract
The microbial communities in the pig gut perform a variety of beneficial functions. Along with host genetics and diet, farm management practices are an important aspect of agricultural animal production that could influence gut microbial diversity. In this study, we used barcoded pyrosequencing of the V1-V3 regions of the 16S ribosomal RNA (rRNA) genes to characterise the faecal microbiome of three common commercial purebred pig lines (Duroc, Landrace and Yorkshire) before and after cohabitation. The diversity of faecal microbiota was characterised by employing phylogenetic, distance-based and multivariate-clustering approaches. Bacterial diversity tended to become more uniform after mixing of the litters. Age-related shifts were also observed at various taxonomic levels, with an increase in the proportion of the phylum Firmicutes and a decrease in Bacteroidetes over time, regardless of the purebred group. Cohabitation had a detectable effect on the microbial shift among purebred pigs. We identified the bacterial genus Parasutterella as having utility in discriminating pigs according to time. Similarly, Dialister and Bacteroides can be used to differentiate the purebred lines used. The microbial communities of the three purebred pigs became more similar after cohabitation, but retained a certain degree of breed specificity, with the microbiota of Landrace and Yorkshire remaining distinct from that of their distant relative, Duroc.
Collapse
|
17
|
Abstract
The gastrointestinal tract is heavily colonized with commensal microbes with the concentration of bacteria increasing longitudinally down the length of the intestine. Bacteria are also spatially distributed transversely from the epithelial surface to the intestinal lumen with the inner mucus layer normally void of bacteria. Maintenance of this equilibrium is extremely important for human health and, as the dominant immunoglobulin at mucosal sites, IgA influences mutualism between the host and its normal microbiota. In this review we focus on the links between immune and microbial geography of the mammalian intestinal tract.
Collapse
|
18
|
Bibiloni R. Rodent models to study the relationships between mammals and their bacterial inhabitants. Gut Microbes 2012; 3:536-43. [PMID: 22918304 PMCID: PMC3495791 DOI: 10.4161/gmic.21905] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Laboratory rodents have been instrumental in helping researchers to unravel the complex interactions that mammals have with their microbial commensals. Progress in defining these interactions has also been possible thanks to the development of culture-independent methods for describing the microbiota associated to body surfaces. Understanding the mechanisms that govern this relationship at the molecular, cellular, and ecological levels is central to both health and disease. The present review of rodent models commonly used to investigate microbial-host "conversations" is focused on those complex bacterial communities residing in the lower gut. Although many types of pathology have been studied using gnotobiotic animals, only the models relevant to commensal bacteria will be described.
Collapse
|
19
|
Fagundes CT, Amaral FA, Teixeira AL, Souza DG, Teixeira MM. Adapting to environmental stresses: the role of the microbiota in controlling innate immunity and behavioral responses. Immunol Rev 2012; 245:250-64. [PMID: 22168425 DOI: 10.1111/j.1600-065x.2011.01077.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Mammals are subject to colonization by an astronomical number of mutualistic and commensal microorganisms on their environmental exposed surfaces. These mutualistic species build up a complex community, called the indigenous microbiota, which aid their hosts in several physiological activities. In this review, we show that the transition between a non-colonized and a colonized state is associated with modification on the pattern of host inflammatory and behavioral responsiveness. There is a shift from innate anti-inflammatory cytokine production to efficient release of proinflammatory mediators and rapid mobilization of leukocytes upon infection or other stimuli. In addition, host responses to hypernociceptive and stressful stimuli are modulated by indigenous microbiota, partly due to the altered pattern of innate and acquired immune responsiveness of the non-colonized host. These altered responses ultimately lead to significant alteration in host behavior to environmental threats. Therefore, host colonization by indigenous microbiota modifies the way the host perceives and reacts to environmental stimuli, improving resilience of the entire host-microorganism consortium to environmental stresses.
Collapse
Affiliation(s)
- Caio T Fagundes
- Immunopharmacology, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | | | | | | |
Collapse
|
20
|
Control of host inflammatory responsiveness by indigenous microbiota reveals an adaptive component of the innate immune system. Microbes Infect 2011; 13:1121-32. [DOI: 10.1016/j.micinf.2011.07.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 07/23/2011] [Accepted: 07/25/2011] [Indexed: 01/15/2023]
|
21
|
Rezzonico E, Mestdagh R, Delley M, Combremont S, Dumas ME, Holmes E, Nicholson J, Bibiloni R. Bacterial adaptation to the gut environment favors successful colonization: microbial and metabonomic characterization of a simplified microbiota mouse model. Gut Microbes 2011; 2:307-18. [PMID: 22157236 PMCID: PMC3337120 DOI: 10.4161/gmic.18754] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Rodent models harboring a simple yet functional human intestinal microbiota provide a valuable tool to study the relationships between mammals and their bacterial inhabitants. In this study, we aimed to develop a simplified gnotobiotic mouse model containing 10 easy-to-grow bacteria, readily available from culture repositories, and of known genome sequence, that overall reflect the dominant commensal bacterial makeup found in adult human feces. We observed that merely inoculating a mix of fresh bacterial cultures into ex-germ free mice did not guarantee a successful intestinal colonization of the entire bacterial set, as mice inoculated simultaneously with all strains only harbored 3 after 21 d. Therefore, several inoculation procedures were tested and levels of individual strains were quantified using molecular tools. Best results were obtained by inoculating single bacterial strains into individual animals followed by an interval of two weeks before allowing the animals to socialize to exchange their commensal microbes. Through this procedure, animals were colonized with almost the complete bacterial set (9/10). Differences in the intestinal composition were also reflected in the urine and plasma metabolic profiles, where changes in lipids, SCFA, and amino acids were observed. We conclude that adaptation of bacterial strains to the host's gut environment (mono-colonization) may predict a successful establishment of a more complex microbiota in rodents.
Collapse
Affiliation(s)
- Enea Rezzonico
- Nestlé Research Centre; Bioanalytical Science Department; Lausanne, Switzerland
| | - Renaud Mestdagh
- Division of Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine; Imperial College London; London, UK
| | - Michèle Delley
- Nestlé Research Centre; Bioanalytical Science Department; Lausanne, Switzerland
| | - Séverine Combremont
- Nestlé Research Centre; Bioanalytical Science Department; Lausanne, Switzerland
| | - Marc-Emmanuel Dumas
- Division of Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine; Imperial College London; London, UK
| | - Elaine Holmes
- Division of Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine; Imperial College London; London, UK
| | - Jeremy Nicholson
- Division of Biomolecular Medicine, Department of Surgery and Cancer, Faculty of Medicine; Imperial College London; London, UK
| | - Rodrigo Bibiloni
- Nestlé Research Centre; Bioanalytical Science Department; Lausanne, Switzerland,Correspondence to: Rodrigo Bibiloni,
| |
Collapse
|
22
|
|
23
|
Axelsson LG, Midtvedt T, Bylund-Fellenius AC. The Role of Intestinal Bacteria, Bacterial Translocation and Endotoxin in Dextran Sodium Sulphate-Induced Colitis in the Mouse. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.3109/08910609609166463] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- L.-G. Axelsson
- Pharmacia and Upjohn AB, Department of Pharmacology, S-751 82, Uppsala, Sweden
- Department of Animal Physiology, Uppsala University, S-751 24, Uppsala, Sweden
| | - T. Midtvedt
- Laboratory of Medical Microbial Ecology, Department of Cell and Molecular Biology, Karolinska Institute, S-104 01, Stockholm, Sweden
| | - A.-C. Bylund-Fellenius
- Department of Food Science, Swedish University of Agricultural Sciences, S-750 07, Uppsala, Sweden
| |
Collapse
|
24
|
Wong WC, Hentges DJ, Dougherty SH. Adequacy of the Human Faecal Microbiota Associated Mouse as a Model for Studying the Ecology of the Human Intestinal Tract. MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.3109/08910609609166459] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- W. C. Wong
- Department of Microbiology and Immunology, Texas Tech. University Health Sciences Center, Lubbock, TexasUSA
| | - D. J. Hentges
- Department of Microbiology and Immunology, Texas Tech. University Health Sciences Center, Lubbock, TexasUSA
| | - S. H. Dougherty
- Department of Microbiology and Immunology, Texas Tech. University Health Sciences Center, Lubbock, TexasUSA
| |
Collapse
|
25
|
Thompson CL, Wang B, Holmes AJ. The immediate environment during postnatal development has long-term impact on gut community structure in pigs. ISME JOURNAL 2008; 2:739-48. [DOI: 10.1038/ismej.2008.29] [Citation(s) in RCA: 152] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
26
|
LEV M. GERM FREE ANIMALS AND THEIR USES IN ELUCIDATING THE ACTION OF THE GUT FLORA ON THE HOST. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1961.tb00263.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
27
|
Smith K, McCoy KD, Macpherson AJ. Use of axenic animals in studying the adaptation of mammals to their commensal intestinal microbiota. Semin Immunol 2006; 19:59-69. [PMID: 17118672 DOI: 10.1016/j.smim.2006.10.002] [Citation(s) in RCA: 531] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Accepted: 10/26/2006] [Indexed: 12/24/2022]
Abstract
Vertebrates are essentially born germ-free but normally acquire a complex intestinal microbiota soon after birth. Most of these organisms are non-pathogenic to immunocompetent hosts; in fact, many are beneficial, supplying vitamins for host nutrition and filling the available microbiological niche to limit access and consequent pathology when pathogens are encountered. Thus, mammalian health depends on mutualism between host and flora. This is evident in inflammatory conditions such as inflammatory bowel disease, where aberrant responses to microbiota can result in host pathology. Studies with axenic (germ-free) or deliberately colonised animals have revealed that commensal organisms are required for the development of a fully functional immune system and affect many physiological processes within the host. Here, we describe the technical requirements for raising and maintaining axenic and gnotobiotic animals, and highlight the extreme diversity of changes within and beyond the immune system that occur when a germ-free animal is colonized with commensal bacteria.
Collapse
Affiliation(s)
- Karen Smith
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | | | | |
Collapse
|
28
|
Macpherson AJ. IgA adaptation to the presence of commensal bacteria in the intestine. Curr Top Microbiol Immunol 2006; 308:117-36. [PMID: 16922088 DOI: 10.1007/3-540-30657-9_5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The lower intestine of mammals is colonised by a dense flora composed mainly of non-pathogenic commensal bacteria. These intestinal bacteria have a wide-ranging impact on host immunity and physiology. One adaptation following intestinal colonisation is increased production and secretion of polyspecific intestinal IgA. In contrast to the strong mucosal immune response to bacterial colonisation, the systemic immune system remains ignorant of these organisms in pathogen-free mice. Small numbers of bacteria can penetrate the epithelial surface overlying Peyer's patches and survive in dendritic cells to induce IgA by T-dependent and T-independent mechanisms. These dendritic cells loaded with live commensal organisms can home to the mesenteric lymph nodes but do not reach systemic secondary lymphoid structures, so induction of mucosal responses is focused in mucosal lymphoid tissues. The secretion of antibodies across the intestinal epithelial surface in turn limits the penetration of commensal organisms, but this is one of many mechanisms which adapt the intestinal mucosa to co-existence with commensal bacteria.
Collapse
Affiliation(s)
- A J Macpherson
- Department of Medicine, McMaster University Medical Center, Room 3N51H, 1200 Main St. West, Hamilton Ontario, L8 N 3Z5, Canada.
| |
Collapse
|
29
|
Lyczak JB. Commensal bacteria increase invasion of intestinal epithelium by Salmonella enterica serovar Typhi. Infect Immun 2003; 71:6610-4. [PMID: 14573683 PMCID: PMC219600 DOI: 10.1128/iai.71.11.6610-6614.2003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intestinal microflora consists of a heterogeneous population of microorganisms and has many effects on the health status of its human host. Here, it is shown that the products of certain strains of bacteria normally present in the intestinal microflora are able to trigger redistribution of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in epithelial cells. CFTR is used by Salmonella enterica serovar Typhi as a receptor on epithelial cells which mediate the translocation of this microorganism to the gastric submucosa. Serovar Typhi-epithelial cell adhesion and CFTR-dependent invasion by serovar Typhi of epithelial cells were increased following commensal-mediated CFTR redistribution. These data suggest that commensal microorganisms present in the intestinal lumen can affect the efficiency of serovar Typhi invasion of the intestinal submucosa. This could be a key factor influencing host susceptibility to typhoid fever.
Collapse
Affiliation(s)
- Jeffrey B Lyczak
- The Channing Laboratory, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA.
| |
Collapse
|
30
|
Horie H, Zeisig M, Hirayama K, Midtvedt T, Möller L, Rafter J. Probiotic mixture decreases DNA adduct formation in colonic epithelium induced by the food mutagen 2-amino-9H-pyrido[2,3-b]indole in a human-flora associated mouse model. Eur J Cancer Prev 2003; 12:101-7. [PMID: 12671533 DOI: 10.1097/00008469-200304000-00003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Consumption of probiotic bacteria such as bifidobacteria has been shown to reduce the risk of colon cancer in animal models. However, the composition and metabolic activities of the intestinal flora of experimental animals are significantly different from those of humans. The aim of the study was to examine whether the probiotic mixture, which consisted of Streptococcus faecalis, Clostridium butyricum and Bacillus mesentericus, could decrease DNA adduct formation induced by 2-amino-9H-pyrido[2,3-b]indole (2-amino-alpha-carboline; AAC) in the colonic epithelium of a human-flora-associated (HFA) mouse model. Ten HFA mice were divided into a control group (n=4) and a probiotic group (n=6). The control group was administered AAC for 3 days and sacrificed 24 h after the last dose. The probiotic group was administered the probiotic mixture for 2 weeks prior to the administration of AAC. Analysis of DNA adducts with the 32P-high-performance liquid chromatography method was performed on stomach, jejunum and colonic epithelium, representing direct exposure sites of AAC, and colon wall, liver and kidney, representing indirect exposure sites. The mean level of the DNA adducts in the colonic epithelium of the probiotic group was significantly lower than that of control group, while the mean levels at the other sites did not differ significantly between the groups. The results indicated that the probiotic mixture could decrease the DNA adduct formation in the colonic epithelium induced by AAC.
Collapse
Affiliation(s)
- H Horie
- Department of Medical Nutrition, Karolinska Institutet, Stockholm, Sweden
| | | | | | | | | | | |
Collapse
|
31
|
FALK P. Exploring the Molecular Basis of Host-Microbial Interactions in the GI Tract. Biosci Microflora 2002. [DOI: 10.12938/bifidus1996.21.83] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
32
|
Falk PG, Hooper LV, Midtvedt T, Gordon JI. Creating and maintaining the gastrointestinal ecosystem: what we know and need to know from gnotobiology. Microbiol Mol Biol Rev 1998; 62:1157-70. [PMID: 9841668 PMCID: PMC98942 DOI: 10.1128/mmbr.62.4.1157-1170.1998] [Citation(s) in RCA: 394] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Studying the cross talk between nonpathogenic organisms and their mammalian hosts represents an experimental challenge because these interactions are typically subtle and the microbial societies that associate with mammalian hosts are very complex and dynamic. A large, functionally stable, climax community of microbes is maintained in the murine and human gastrointestinal tracts. This open ecosystem exhibits not only regional differences in the composition of its microbiota but also regional differences in the differentiation programs of its epithelial cells and in the spatial distribution of its component immune cells. A key experimental strategy for determining whether "nonpathogenic" microorganisms actively create their own regional habitats in this ecosystem is to define cellular function in germ-free animals and then evaluate the effects of adding single or several microbial species. This review focuses on how gnotobiotics-the study of germ-free animals-has been and needs to be used to examine how the gastrointestinal ecosystem is created and maintained. Areas discussed include the generation of simplified ecosystems by using genetically manipulatable microbes and hosts to determine whether components of the microbiota actively regulate epithelial differentiation to create niches for themselves and for other organisms; the ways in which gnotobiology can help reveal collaborative interactions among the microbiota, epithelium, and mucosal immune system; and the ways in which gnotobiology is and will be useful for identifying host and microbial factors that define the continuum between nonpathogenic and pathogenic. A series of tests of microbial contributions to several pathologic states, using germ-free and ex-germ-free mice, are proposed.
Collapse
Affiliation(s)
- P G Falk
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | | | | | | |
Collapse
|
33
|
Abstract
No urobilinogens are present in the feces or urine of germfree rats. After contamination of germfree animals with feces from conventional animals the exgermfree rats produced urobilins to the same extent as conventional animals on the same diet. The negative urobilin test turned positive in germfree animals infected with a single Clostridium-like microorganism isolated from the intestinal contents of rats with urobilins in the feces. The output increased in these monoinfected animals after superinfection with a strain of E. coli but never reached the values of conventional animals.
Collapse
|
34
|
DANIELSSON H, GUSTAFSSON B. On serum-cholesterol levels and neutral fecal sterols in germ-free rats; bile acids and steroids 59. Arch Biochem Biophys 1998; 83:482-5. [PMID: 13813997 DOI: 10.1016/0003-9861(59)90056-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
35
|
Davidson RT, Foley AL, Engelke JA, Suttie JW. Conversion of dietary phylloquinone to tissue menaquinone-4 in rats is not dependent on gut bacteria. J Nutr 1998; 128:220-3. [PMID: 9446847 DOI: 10.1093/jn/128.2.220] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The ability of male rats to accumulate menaquinone-4 (MK-4) in tissues when fed a vitamin K-deficient diet supplemented with intraperitoneal phylloquinone (K) as the sole source of vitamin K for 14 d was assessed. In both conventionally housed controls and gnotobiotic rats, supplementation with the equivalent of 1500 microg vitamin K/kg diet increased (P < 0.001) tissue MK-4 concentrations above those of controls fed a vitamin K-deficient diet. MK-4 concentrations were approximately 5 ng/g (11 pmol/g) in liver, 14 ng/g in heart, 17 ng/g in kidney, 50 ng/g in brain and 250 ng/g in mandibular salivary glands of gnotobiotic rats. MK-4 concentrations in conventionally housed rats were higher than in gnotobiotic rats in heart (P < 0.01), brain (P < 0.01) and kidney (P < 0.05) but lower in salivary gland (P < 0.05). Cultures of a kidney-derived cell line (293) converted K to the expoxide of MK-4 in a manner that was dependent on both time of incubation and concentration of vitamin K in the media. A liver-derived cell line (H-35) was less active in carrying out this conversion. These data offer conclusive proof that the tissue-specific formation of MK-4 from K is a metabolic transformation that does not require bacterial transformation to menadione as an intermediate in the process.
Collapse
Affiliation(s)
- R T Davidson
- Department of Nutritional Sciences, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | | | | |
Collapse
|
36
|
Akiyama Y, Hara K, Matsumoto A, Takahashi S, Tajima T. Comparison of intestinal absorption of vitamin K2 (menaquinone) homologues and their effects on blood coagulation in rats with hypoprothrombinaemia. Biochem Pharmacol 1995; 49:1801-7. [PMID: 7598742 DOI: 10.1016/0006-2952(94)00531-p] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To examine the physiological activities of vitamin K2 (menaquinone, MK) homologues with different numbers of isoprene units, MK with 1-14 isoprene units and menadione (MK-0) were administered to rats with hypoprothrombinaemia, and the absorption, concentration in liver and ameliorating effect of these MK on hypoprothrombinaemia were compared. Hypoprothrombinaemia was induced by giving a vitamin K-deficient diet and warfarin (0.06 mg/kg body weight) for 8 days. Before MK treatment, the MK were undetectable in plasma and liver. At 6 hr after oral MK administration (0.1 mg/kg): MK was not detected in the plasma in rats treated with MK with 1, 2, 3 or more than 12 isoprene units; the MK level in the liver was increased but blood coagulation activity was not improved in rats treated with MK with 0, 9, 10 or 11 isoprene units; the MK level in the liver was increased and hypoprothrombinaemia was slightly improved in rats treated with MK with 7 or 8 isoprene units; and the MK level in the liver was increased and hypoprothrombinaemia was markedly improved in rats treated with MK with 4, 5 or 6 isoprene units. Almost identical results were observed 3 hr after intravenous injection of MK with 4, 5 or 6 isoprene units (10 nmol/kg). These findings suggest that the number of isoprene units of MK is an important factor in its absorption and incorporation into the liver and that the ameliorating effect of MK on hypoprothrombinaemia does not parallel their concentrations in the liver.
Collapse
Affiliation(s)
- Y Akiyama
- Department of Drug Research II, Eisai Co. Ltd., Tokyo, Japan
| | | | | | | | | |
Collapse
|
37
|
Mathers JC, Fernandez F, Hill MJ, McCarthy PT, Shearer MJ, Oxley A. Dietary modification of potential vitamin K supply from enteric bacterial menaquinones in rats. Br J Nutr 1990; 63:639-52. [PMID: 2383538 DOI: 10.1079/bjn19900150] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Rats given a low-fibre diet based on boiled white rice developed symptoms of severe vitamin K deficiency within 23 d. Inclusion of autoclaved black-eye beans (Vigna unguiculata) in the diet prevented the bleeding syndrome. To test the hypothesis that deficiency resulted from low phylloquinone intake exacerbated by inadequate production of menaquinones by the enteric bacteria, a follow-up experiment was carried out in which groups of rats were given an all-rice diet, a rice + beans diet or a stock diet. Rats on the all-rice diet had significantly lower faecal concentrations of the main menaquinone-producing bacterial species (Bacteroides fragilis and Bacteroides vulgatus) than animals on either of the other two diets. This coupled with the much lower faecal output on this diet suggests that total menaquinone production was low for the all-rice diet. The alterations in faecal flora were associated with several significant changes in caecal metabolism. Rats given the stock diet had much shorter caecal transit times and a considerably greater proportion of butyric acid in volatile fatty acid end-products than did rats on either of the other two diets.
Collapse
Affiliation(s)
- J C Mathers
- Department of Agricultural Biochemistry and Nutrition, University of Newcastle, Newcastle upon Tyne
| | | | | | | | | | | |
Collapse
|
38
|
|
39
|
Takahashi O, Hiraga K. Dose--response study of hemorrhagic death by dietary butylated hydroxytoluene (BHT) in male rats. Toxicol Appl Pharmacol 1978; 43:399-406. [PMID: 635926 DOI: 10.1016/0041-008x(78)90019-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
40
|
Brown JP. Role of gut bacterial flora in nutrition and health: a review of recent advances in bacteriological techniques, metabolism, and factors affecting flora composition. CRC CRITICAL REVIEWS IN FOOD SCIENCE AND NUTRITION 1977; 8:229-336. [PMID: 338249 DOI: 10.1080/10408397709527224] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
41
|
Gustafsson BE, Einarsson K, Gustafsson J. Influence of cholesterol feeding on liver microsomal metabolism of steroids and bile acids in conventional and germ-free rats. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)40787-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
42
|
|
43
|
Differences between Germ-free and Conventional Rats in Liver Microsomal Metabolism of Steroids. J Biol Chem 1973. [DOI: 10.1016/s0021-9258(19)43974-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
44
|
The gnotobiotic animal as a tool in the study of host microbial relationships. BACTERIOLOGICAL REVIEWS 1971; 35:390-429. [PMID: 4945725 PMCID: PMC378408 DOI: 10.1128/br.35.4.390-429.1971] [Citation(s) in RCA: 160] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
45
|
Blackmore DK, Green RM. The use of germ-free and specific pathogen-free rats in short-term experiments for the assessment of potentially cariogenic organisms. Arch Oral Biol 1970; 15:1149-55. [PMID: 5280121 DOI: 10.1016/0003-9969(70)90006-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
46
|
Blackmore DK, Drucker DB, Green RM. Caries induction in germ-free rats by streptococci isolated from dental abscesses in man. Arch Oral Biol 1970; 15:1377-9. [PMID: 5280136 DOI: 10.1016/0003-9969(70)90025-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
47
|
Björkhem I, Gustafsson JA, Gustafsson SA. Metabolism of steroids in germfree and conventional rats treated with a 3-beta-Hydroxy-delta-5-steroid oxidoreductase inhibitor. EUROPEAN JOURNAL OF BIOCHEMISTRY 1970; 16:557-66. [PMID: 5477302 DOI: 10.1111/j.1432-1033.1970.tb01117.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
48
|
Gustafsson JA. Steroids in germfree and conventional rats. Steroid monosulphates in urine from female rats. EUROPEAN JOURNAL OF BIOCHEMISTRY 1970; 14:560-6. [PMID: 5479383 DOI: 10.1111/j.1432-1033.1970.tb00324.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
49
|
Eriksson H, Gustafsson JA, Sjövall J. Steroids in germfree and conventional rats. Free steroids in faeces from conventional rats. EUROPEAN JOURNAL OF BIOCHEMISTRY 1969; 9:286-90. [PMID: 5804501 DOI: 10.1111/j.1432-1033.1969.tb00607.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
50
|
Gustafsson JA, Lisboa BP, Sjöval J. Studies on the metabolism of C19-steroids in rat liver. 3. Isolation and biosynthesis of 5alpha-androstanetriols in rat liver microsomes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1968; 6:317-24. [PMID: 5725514 DOI: 10.1111/j.1432-1033.1968.tb00451.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|