Establishing and maintaining beneficial interactions between the host and its associated microbiota are key requirements for host health. Although the gut microbiota has previously been studied in ...the context of inflammatory diseases, it has recently become clear that this microbial community has a beneficial role during normal homeostasis, modulating the host's immune system as well as influencing host development and physiology, including organ development and morphogenesis, and host metabolism. The underlying molecular mechanisms of host-microorganism interactions remain largely unknown, but recent studies have begun to identify the key signalling pathways of the cross-species homeostatic regulation between the gut microbiota and its host.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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Gastrointestinal biofilms in health and disease Motta, Jean-Paul; Wallace, John L; Buret, André G ...
Nature reviews. Gastroenterology & hepatology,
05/2021, Volume:
18, Issue:
5
Journal Article
Peer reviewed
Microorganisms colonize various ecological niches in the human habitat, as they do in nature. Predominant forms of multicellular communities called biofilms colonize human tissue surfaces. The ...gastrointestinal tract is home to a profusion of microorganisms with intertwined, but not identical, lifestyles: as isolated planktonic cells, as biofilms and in biofilm-dispersed form. It is therefore of major importance in understanding homeostatic and altered host-microorganism interactions to consider not only the planktonic lifestyle, but also biofilms and biofilm-dispersed forms. In this Review, we discuss the natural organization of microorganisms at gastrointestinal surfaces, stratification of microbiota taxonomy, biogeographical localization and trans-kingdom interactions occurring within the biofilm habitat. We also discuss existing models used to study biofilms. We assess the contribution of the host-mucosa biofilm relationship to gut homeostasis and to diseases. In addition, we describe how host factors can shape the organization, structure and composition of mucosal biofilms, and how biofilms themselves are implicated in a variety of homeostatic and pathological processes in the gut. Future studies characterizing biofilm nature, physical properties, composition and intrinsic communication could shed new light on gut physiology and lead to potential novel therapeutic options for gastrointestinal diseases.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
Within the human gut reside diverse microbes coexisting with the host in a mutually advantageous relationship. Evidence has revealed the pivotal role of the gut microbiota in shaping the immune ...system. To date, only a few of these microbes have been shown to modulate specific immune parameters. Herein, we broadly identify the immunomodulatory effects of phylogenetically diverse human gut microbes. We monocolonized mice with each of 53 individual bacterial species and systematically analyzed host immunologic adaptation to colonization. Most microbes exerted several specialized, complementary, and redundant transcriptional and immunomodulatory effects. Surprisingly, these were independent of microbial phylogeny. Microbial diversity in the gut ensures robustness of the microbiota’s ability to generate a consistent immunomodulatory impact, serving as a highly important epigenetic system. This study provides a foundation for investigation of gut microbiota-host mutualism, highlighting key players that could identify important therapeutics.
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•Human gut microbiota comprises a treasure trove of immunomodulatory bacteria•Diverse and redundant immune and transcriptional responses follow monocolonization•Immunologic and transcriptional changes are not related to microbial phylogeny•Following monocolonization, immune recalibration varies to strains within a species
Each of 53 human-resident bacterial species studied in monoculture in mice modulates the host immune system, providing a baseline for investigating how consortia of gut microbes interact with their host.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The intestinal crypt is a site of potential interactions between microbiota products, stem cells, and other cell types found in this niche, including Paneth cells, and thus offers a potential for ...commensal microbes to influence the host epithelium. However, the complexity of this microenvironment has been a challenge to deciphering the underlying mechanisms. We used in vitro cultured organoids of intestinal crypts from mice, reinforced with in vivo experiments, to examine the crypt-microbiota interface. We find that within the intestinal crypt, Lgr5+ stem cells constitutively express the cytosolic innate immune sensor Nod2 at levels much higher than in Paneth cells. Nod2 stimulation by its bona fide agonist, muramyl-dipeptide (MDP), a peptidoglycan motif common to all bacteria, triggers stem cell survival, which leads to a strong cytoprotection against oxidative stress-mediated cell death. Thus, gut epithelial restitution is Nod2 dependent and triggered by the presence of microbiota-derived molecules.
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•The bacterial peptidoglycan motif MDP induces higher yield of intestinal organoids in vitro•Nod2 is expressed in Lgr5+ intestinal epithelial stem cells•Stem cell-expressed Nod2 is sufficient to provide cytoprotection•MDP protects stem cells from stress in vivo in a Nod2-dependent manner
The intestinal crypt is the site of epithelial regeneration and of potential interactions between microbiota products and stem cells. Nigro et al. show that intestinal Lgr5+ stem cells express the cytosolic innate immune sensor Nod2, whose stimulation by the bacterial ligand muramyl-dipeptide affords potent cytoprotection to the stem cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Although COVID-19 is primarily a respiratory illness, there is mounting evidence suggesting that the GI tract is involved in this disease. We investigated whether the gut microbiome is linked to ...disease severity in patients with COVID-19, and whether perturbations in microbiome composition, if any, resolve with clearance of the SARS-CoV-2 virus.
In this two-hospital cohort study, we obtained blood, stool and patient records from 100 patients with laboratory-confirmed SARS-CoV-2 infection. Serial stool samples were collected from 27 of the 100 patients up to 30 days after clearance of SARS-CoV-2. Gut microbiome compositions were characterised by shotgun sequencing total DNA extracted from stools. Concentrations of inflammatory cytokines and blood markers were measured from plasma.
Gut microbiome composition was significantly altered in patients with COVID-19 compared with non-COVID-19 individuals irrespective of whether patients had received medication (p<0.01). Several gut commensals with known immunomodulatory potential such as
,
and bifidobacteria were underrepresented in patients and remained low in samples collected up to 30 days after disease resolution. Moreover, this perturbed composition exhibited stratification with disease severity concordant with elevated concentrations of inflammatory cytokines and blood markers such as C reactive protein, lactate dehydrogenase, aspartate aminotransferase and gamma-glutamyl transferase.
Associations between gut microbiota composition, levels of cytokines and inflammatory markers in patients with COVID-19 suggest that the gut microbiome is involved in the magnitude of COVID-19 severity possibly via modulating host immune responses. Furthermore, the gut microbiota dysbiosis after disease resolution could contribute to persistent symptoms, highlighting a need to understand how gut microorganisms are involved in inflammation and COVID-19.
Asthma is a common chronic respiratory disease affecting more than 300 million people worldwide. Clinical features of asthma and its immunological and molecular etiology vary significantly among ...patients. An understanding of the complexities of asthma has evolved to the point where precision medicine approaches, including microbiome analysis, are being increasingly recognized as an important part of disease management. Lung and gut microbiota play several important roles in the development, regulation, and maintenance of healthy immune responses. Dysbiosis and subsequent dysregulation of microbiota-related immunological processes affect the onset of the disease, its clinical characteristics, and responses to treatment. Bacteria and viruses are the most extensively studied microorganisms relating to asthma pathogenesis, but other microbes, including fungi and even archaea, can potently influence airway inflammation. This review focuses on recently discovered connections between lung and gut microbiota, including bacteria, fungi, viruses, and archaea, and their influence on asthma.
Dysregulation of microbiota-related immunological processes affects the onset of asthma, its clinical characteristics, and responses to treatment. Finlay et al. review connections between gut and lungs microbiota and its influence on allergic airway inflammation. This review covers not only the most well-known populations of microbes in the context of asthma—bacteria—but also discusses viruses, fungi, and archaea.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abdominal tuberculosis is an increasingly common disease that poses diagnostic challenge,as the nonspecific features of the disease which may lead to diagnostic delays and development of ...complications.This condition is regarded as a great mimicker of other abdominal pathology.A high index of suspicion is an important factor in early diagnosis.Abdominal involvement mayoccur in the gastrointestinal tract,peritoneum,lymphnodes or solid viscera.Various investigative methods have been used to aid in the diagnosis of abdominal tuberculosis.Early diagnosis and initiation of antituberculous therapy and surgical treatment are essential to prevent morbidity and mortality.Most of the patients respond very well to standard antitubercular therapy and surgery is required only in a minority of cases.Imaging plays an important role in diagnosis of abdominal tuberculosis because early recognition of this condition is important.We reviewed our experience with the findings on various imaging modalities for diagnosis of this potentially treatable disease.
Abstract Autism spectrum disorder (ASD) is a serious neurodevelopmental disorder that affects one in 45 children in the United States, with a similarly striking prevalence in countries around the ...world. However, mechanisms underlying its etiology and manifestations remain poorly understood. While ASD is diagnosed based on the presence and severity of impaired social communication and repetitive behavior, immune dysregulation and gastrointestinal issues are common co-morbidities. The microbiome is an integral part of human physiology; recent studies show that changes in the gut microbiota can modulate gastrointestinal physiology, immune function and even behavior. Links between particular bacteria from the indigenous gut microbiota and phenotypes relevant to ASD raise the important question of whether microbial dysbiosis plays a role in the development or presentation of ASD symptoms. Here we review reports of microbial dysbiosis in ASD. We further discuss potential effects of the microbiota on ASD-associated symptoms, drawing upon signaling mechanisms for reciprocal interactions between the microbiota, immunity, gut function and behavior. In addition, we discuss recent findings supporting a role for the microbiome as an interface between environmental and genetic risk factors that are associated with ASD. These studies highlight the integration of pathways across multiple body systems that together can impact brain and behavior and suggest that changes in the microbiome may contribute to symptoms of neurodevelopmental disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The gastrointestinal tract has recently come to the forefront of multiple research fields. It is now recognized as a major source of signals modulating food intake, insulin secretion and energy ...balance. It is also a key player in immunity and, through its interaction with microbiota, can shape our physiology and behavior in complex and sometimes unexpected ways. The insect intestine had remained, by comparison, relatively unexplored until the identification of adult somatic stem cells in the
intestine over a decade ago. Since then, a growing scientific community has exploited the genetic amenability of this insect organ in powerful and creative ways. By doing so, we have shed light on a broad range of biological questions revolving around stem cells and their niches, interorgan signaling and immunity. Despite their relatively recent discovery, some of the mechanisms active in the intestine of flies have already been shown to be more widely applicable to other gastrointestinal systems, and may therefore become relevant in the context of human pathologies such as gastrointestinal cancers, aging, or obesity. This review summarizes our current knowledge of both the formation and function of the
digestive tract, with a major focus on its main digestive/absorptive portion: the strikingly adaptable adult midgut.
Intestinal peristalsis is a dynamic physiologic process influenced by dietary and microbial changes. It is tightly regulated by complex cellular interactions; however, our understanding of these ...controls is incomplete. A distinct population of macrophages is distributed in the intestinal muscularis externa. We demonstrate that, in the steady state, muscularis macrophages regulate peristaltic activity of the colon. They change the pattern of smooth muscle contractions by secreting bone morphogenetic protein 2 (BMP2), which activates BMP receptor (BMPR) expressed by enteric neurons. Enteric neurons, in turn, secrete colony stimulatory factor 1 (CSF1), a growth factor required for macrophage development. Finally, stimuli from microbial commensals regulate BMP2 expression by macrophages and CSF1 expression by enteric neurons. Our findings identify a plastic, microbiota-driven crosstalk between muscularis macrophages and enteric neurons that controls gastrointestinal motility.
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•Muscularis macrophages produce BMP2 that activates BMPR on enteric neurons•Enteric neurons produce CSF1 that promotes homeostasis of muscularis macrophages•Macrophage-neuronal crosstalk regulates constitutive gastrointestinal motility•Macrophage-neuronal crosstalk is driven by gut microbiota
A unique population of macrophages residing in the smooth muscle of the gut regulates gastrointestinal motility by communicating with enteric neurons. This macrophage-neuronal dialog is plastic and is affected by intestinal microbiota, a discovery that offers mechanistic insights into gastrointestinal motility disorders.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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