The Influence of the Microbiome on Allergic Sensitization to Food

Author: Plunkett, Catherine H.; Nagler, Cathryn R. Description: The alarming increase in the incidence and severity of food allergies has coincided with lifestyle changes in Western societies, such as dietary modifications and increased antibiotic use. These demographic shifts have profoundly altered the coevolved relationship between host and microbiota, depleting bacterial populations critical for the maintenance of mucosal homeostasis. There is increasing evidence that the dysbiosis associated with sensitization to food fails to stimulate protective tolerogenic pathways, leading to the development of the type 2 immune responses that characterize allergic disease….

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Microbiota in pancreatic health and disease: the next frontier in microbiome research

Author: Thomas, R. M., & Jobin, C. Description: Diseases intrinsic to the pancreas such as pancreatitis, pancreatic cancer and type 1 diabetes mellitus impart substantial health and financial burdens on society but identification of novel mechanisms contributing to these pathologies are slow to emerge. A novel area of research suggests that pancreatic-specific disorders might be modulated by the gut microbiota, either through a local (direct pancreatic influence) or in a remote (nonpancreatic) fashion. In this Perspectives, we examine literature implicating microorganisms in diseases of the pancreas, specifically pancreatitis, type 1…

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Why does the microbiome affect behaviour?

Author: Johnson, K. V.-A., & Foster, K. R. Description: Growing evidence indicates that the mammalian microbiome can affect behaviour, and several symbionts even produce neurotransmitters. One common explanation for these observations is that symbionts have evolved to manipulate host behaviour for their benefit. Here, we evaluate the manipulation hypothesis by applying evolutionary theory to recent work on the gut-brain axis. Although the theory predicts manipulation by symbionts under certain conditions, these appear rarely satisfied by the genetically diverse communities of the mammalian microbiome. Specifically, any symbiont investing its resources to…

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Of the bugs that shape us: maternal obesity, the gut microbiome, and long-term disease risk

Author: Gohir, W., Ratcliffe, E. M., & Sloboda, D. M. Description: Chronic disease risk is inextricably linked to our early-life environment, where maternal, fetal, and childhood factors predict disease risk later in life. Currently, maternal obesity is a key predictor of childhood obesity and metabolic complications in adulthood. Although the mechanisms are unclear, new and emerging evidence points to our microbiome, where the bacterial composition of the gut modulates the weight gain and altered metabolism that drives obesity. Over the course of pregnancy, maternal bacterial load increases, and gut bacterial…

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Current explorations of nutrition and the gut microbiome: a comprehensive evaluation of the review literature

Author: Frame, L. A., Costa, E., & Jackson, S. A. Description: CONTEXT: The ability to measure the gut microbiome led to a surge in understanding and knowledge of its role in health and disease. The diet is a source of fuel for and influencer of composition of the microbiome. OBJECTIVE: To assess the understanding of the interactions between nutrition and the gut microbiome in healthy adults. DATA SOURCES: PubMed and Google Scholar searches were conducted in March and August 2018 and were limited to the following: English, 2010-2018, healthy adults,…

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Bacteriophage-mediated manipulation of the gut microbiome – promises and present limitations

Author: Rasmussen, T. S.; Koefoed, A. K.; Jakobsen, R. R.; Deng, L.; Castro-Mejía, J. L.; Brunse, A.; Neve, H.; Vogensen, F. K. & Nielsen, D. S. Description: Gut microbiome (GM) composition and function are linked to human health and disease, and routes for manipulating the GM have become an area of intense research. Due to its high treatment efficacy, the use of fecal microbiota transplantation (FMT) is generally accepted as a promising experimental treatment for patients suffering from GM imbalances (dysbiosis), e.g. caused by recurrent Clostridioides difficile infections (rCDI). Mounting…

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The Bacteroides fragilis pathogenicity island links virulence and strain competition

Author: Casterline, Benjamin W.; Hecht, Aaron L.; Choi, Vivian M.; Bubeck Wardenburg, Juliane Description: The mature microbiome is a stable ecosystem that resists perturbation despite constant host exposure to exogenous microbes. However, the microbial mechanisms determining microbiome development and composition are poorly understood. We recently demonstrated that a non-toxigenic B. fragilis (NTBF) strain restricts enteric colonization by an enterotoxigenic (ETBF) strain dependent on a type VI secretion system (T6SS). We show here that a second enterotoxigenic strain is competent to colonize, dependent on the Bacteroides fragilis pathogenicity island (BFPAI). Additional…

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Microbiota depletion promotes browning of white adipose tissue and reduces obesity

Author: Suarez-Zamorano, Nicolas; Fabbiano, Salvatore; Chevalier, Claire; Stojanovic, Ozren; Colin, Didier J.; Stevanovic, Ana; Veyrat-Durebex, Christelle; Tarallo, Valentina; Rigo, Dorothee; Germain, Stephane; Ilievska, Miroslava; Montet, Xavier; Seimbille, Yann; Hapfelmeier, Siegfried; Trajkovski, Mirko Description: Brown adipose tissue (BAT) promotes a lean and healthy phenotype and improves insulin sensitivity. In response to cold or exercise, brown fat cells also emerge in the white adipose tissue (WAT; also known as beige cells), a process known as browning. Here we show that the development of functional beige fat in the inguinal subcutaneous adipose tissue…

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Autoimmune host-microbiota interactions at barrier sites and beyond

Author: Ruff, William E.; Kriegel, Martin A. Description: The microbiota is considered to be an important factor influencing the pathogenesis of autoimmunity at both barrier sites and internal organs. Impinging on innate and adaptive immunity, commensals exert protective or detrimental effects on various autoimmune animal models. Human microbiome studies of autoimmunity remain largely descriptive, but suggest a role for dysbiosis in autoimmune disease. Humanized gnotobiotic approaches have advanced our understanding of immune-commensal interactions, but little is known about the mechanisms in autoimmunity. We propose that, similarly to infectious agents, the…

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Immune-microbiota interactions in health and disease

Author: Palm, Noah W.; de Zoete, Marcel R.; Flavell, Richard A. Description: Recent studies have revealed that the intestinal microbiota plays an important role in host physiology and pathophysiology in health and disease. One of the major mechanisms by which the gut microbiota influences the host is through its interactions with and effects on the host immune system. In this review, we discuss the reciprocal interactions between the host immune system and the gut microbiota, with a particular focus on individual microbes that impact the host through dramatic and specific…

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