Trillions of microorganisms transit through and reside in the mammalian gastrointestinal tract each day, collectively producing thousands of small molecules and metabolites with local and systemic ...effects on host physiology. Identifying effector microorganisms that causally affect host phenotype and deciphering the underlying mechanisms have become foci of microbiome research and have begun to enable the development of microbiota-based therapeutics. Two complementary, reductionist approaches have commonly been used: the first starts with an immune phenotype and narrows down the microbiota to identify responsible effector bacteria, while the second starts with bacteria-derived molecules and metabolites and seeks to understand their effects on the host immune system. Together, these strategies provide the basis for the rational design of microbial and metabolite-based therapeutics that target and ameliorate immune deficits in patients.
T Cell Responses to the Microbiota Ivanov, Ivaylo I; Tuganbaev, Timur; Skelly, Ashwin N ...
Annual review of immunology,
04/2022, Letnik:
40, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The immune system employs recognition tools to communicate with its microbial evolutionary partner. Among all the methods of microbial perception, T cells enable the widest spectrum of microbial ...recognition resolution, ranging from the crudest detection of whole groups of microbes to the finest detection of specific antigens. The application of this recognition capability to the crucial task of combatting infections has been the focus of classical immunology. We now appreciate that the coevolution of the immune system and the microbiota has led to development of a lush immunological decision tree downstream of microbial recognition, of which an inflammatory response is but one branch. In this review we discuss known T cell-microbe interactions in the gut and place them in the context of an algorithmic framework of recognition, context-dependent interpretation, and response circuits across multiple levels of microbial recognition resolution. The malleability of T cells in response to the microbiota presents an opportunity to edit immune response cellularity, identity, and functionality by utilizing microbiota-controlled pathways to promote human health.
Centenarians have a decreased susceptibility to ageing-associated illnesses, chronic inflammation and infectious diseases
. Here we show that centenarians have a distinct gut microbiome that is ...enriched in microorganisms that are capable of generating unique secondary bile acids, including various isoforms of lithocholic acid (LCA): iso-, 3-oxo-, allo-, 3-oxoallo- and isoallolithocholic acid. Among these bile acids, the biosynthetic pathway for isoalloLCA had not been described previously. By screening 68 bacterial isolates from the faecal microbiota of a centenarian, we identified Odoribacteraceae strains as effective producers of isoalloLCA both in vitro and in vivo. Furthermore, we found that the enzymes 5α-reductase (5AR) and 3β-hydroxysteroid dehydrogenase (3β-HSDH) were responsible for the production of isoalloLCA. IsoalloLCA exerted potent antimicrobial effects against Gram-positive (but not Gram-negative) multidrug-resistant pathogens, including Clostridioides difficile and Enterococcus faecium. These findings suggest that the metabolism of specific bile acids may be involved in reducing the risk of infection with pathobionts, thereby potentially contributing to the maintenance of intestinal homeostasis.
There is a growing appreciation for the importance of the gut microbiota as a therapeutic target in various diseases. However, there are only a handful of known commensal strains that can potentially ...be used to manipulate host physiological functions. Here we isolate a consortium of 11 bacterial strains from healthy human donor faeces that is capable of robustly inducing interferon-γ-producing CD8 T cells in the intestine. These 11 strains act together to mediate the induction without causing inflammation in a manner that is dependent on CD103
dendritic cells and major histocompatibility (MHC) class Ia molecules. Colonization of mice with the 11-strain mixture enhances both host resistance against Listeria monocytogenes infection and the therapeutic efficacy of immune checkpoint inhibitors in syngeneic tumour models. The 11 strains primarily represent rare, low-abundance components of the human microbiome, and thus have great potential as broadly effective biotherapeutics.
Not all persons recovering from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection develop SARS-CoV-2-specific antibodies. We show that nonseroconversion is associated with ...younger age and higher reverse transcription PCR cycle threshold values and identify SARS-CoV-2 viral loads in the nasopharynx as a major correlate of the systemic antibody response.
Recent advances in sample preparation protocols and instrumentation allow current imaging mass spectrometry (IMS) to enable the visualization of small molecule tissue localization, including that of ...monoamine neurotransmitters, such as serotonin, dopamine, and norepinephrine. Although monoamine-producing neurons, and their projections and synaptic connections, have been thoroughly characterized, in situ monoamine localization within these circuits remains unclear. Moreover, studying the fluctuations in local monoamine concentration in response to physiological stimuli, drug administration, and neurodegenerative disease progression is worthwhile, and can be achieved by analyzing the in situ concentration maps afforded by coupling IMS with on-tissue derivatization protocols. Recent reports have shown that monoamines localize within cell bodies and also translocate to distant nerve terminals, indicating active transport along axons and/or local synthesis at the terminals. Moreover, IMS can reveal regionally segregated monoamine fluctuations, such as rapid dopamine fluctuation within the nucleus accumbens (NAc) subregion during pain sensation. Furthermore, since exogenous drug pharmacokinetics can also be visualized by IMS, this technique could provide powerful methodologies enabling the simultaneous imaging of monoamines and drugs that selectively regulate monoamine signaling, such as serotonin reuptake inhibitors (SSRIs). Therefore, IMS could reveal where SSRIs administered over the long-term accumulate and how they affect local monoamine metabolism.
Host-microbe interactions orchestrate skin homeostasis, the dysregulation of which has been implicated in chronic inflammatory conditions such as atopic dermatitis and psoriasis. Here, we show that ...Staphylococcus cohnii is a skin commensal capable of beneficially inhibiting skin inflammation. We find that Tmem79−/− mice spontaneously develop interleukin-17 (IL-17)-producing T-cell-driven skin inflammation. Comparative skin microbiome analysis reveals that the disease activity index is negatively associated with S. cohnii. Inoculation with S. cohnii strains isolated from either mouse or human skin microbiota significantly prevents and ameliorates dermatitis in Tmem79−/− mice without affecting pathobiont burden. S. cohnii colonization is accompanied by activation of host glucocorticoid-related pathways and induction of anti-inflammatory genes in the skin and is therefore effective at suppressing inflammation in diverse pathobiont-independent dermatitis models, including chemically induced, type 17, and type 2 immune-driven models. As such, S. cohnii strains have great potential as effective live biotherapeutics for skin inflammation.
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•Skin microbiota dysbiosis drives chronic dermatitis in Tmem79−/− mice•Staphylococcus cohnii provides therapeutic benefits in Tmem79−/− mice•S. cohnii suppresses chemically induced atopic dermatitis and psoriasis•S. cohnii induces anti-inflammatory and glucocorticoid-related genes
The skin microbiota is an attractive therapeutic target for the treatment and/or prevention of atopic dermatitis and psoriasis. Ito et al. show that rationally identified Staphylococcus cohnii strains from human and mice are capable of providing therapeutic benefits by potently inhibiting type 2 and type 17 skin inflammation.
After emerging in China in late 2019, the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread worldwide, and as of mid-2021, it remains a significant threat ...globally. Only a few coronaviruses are known to infect humans, and only two cause infections similar in severity to SARS-CoV-2:
, a species closely related to SARS-CoV-2 that emerged in 2002, and
, which emerged in 2012. Unlike the current pandemic, previous epidemics were controlled rapidly through public health measures, but the body of research investigating severe acute respiratory syndrome and Middle East respiratory syndrome has proven valuable for identifying approaches to treating and preventing novel coronavirus disease 2019 (COVID-19). Building on this research, the medical and scientific communities have responded rapidly to the COVID-19 crisis and identified many candidate therapeutics. The approaches used to identify candidates fall into four main categories: adaptation of clinical approaches to diseases with related pathologies, adaptation based on virological properties, adaptation based on host response, and data-driven identification (ID) of candidates based on physical properties or on pharmacological compendia. To date, a small number of therapeutics have already been authorized by regulatory agencies such as the Food and Drug Administration (FDA), while most remain under investigation. The scale of the COVID-19 crisis offers a rare opportunity to collect data on the effects of candidate therapeutics. This information provides insight not only into the management of coronavirus diseases but also into the relative success of different approaches to identifying candidate therapeutics against an emerging disease.
The COVID-19 pandemic is a rapidly evolving crisis. With the worldwide scientific community shifting focus onto the SARS-CoV-2 virus and COVID-19, a large number of possible pharmaceutical approaches for treatment and prevention have been proposed. What was known about each of these potential interventions evolved rapidly throughout 2020 and 2021. This fast-paced area of research provides important insight into how the ongoing pandemic can be managed and also demonstrates the power of interdisciplinary collaboration to rapidly understand a virus and match its characteristics with existing or novel pharmaceuticals. As illustrated by the continued threat of viral epidemics during the current millennium, a rapid and strategic response to emerging viral threats can save lives. In this review, we explore how different modes of identifying candidate therapeutics have borne out during COVID-19.
The novel coronavirus SARS-CoV-2, which emerged in late 2019, has since spread around the world and infected hundreds of millions of people with coronavirus disease 2019 (COVID-19). While this viral ...species was unknown prior to January 2020, its similarity to other coronaviruses that infect humans has allowed for rapid insight into the mechanisms that it uses to infect human hosts, as well as the ways in which the human immune system can respond. Here, we contextualize SARS-CoV-2 among other coronaviruses and identify what is known and what can be inferred about its behavior once inside a human host. Because the genomic content of coronaviruses, which specifies the virus's structure, is highly conserved, early genomic analysis provided a significant head start in predicting viral pathogenesis and in understanding potential differences among variants. The pathogenesis of the virus offers insights into symptomatology, transmission, and individual susceptibility. Additionally, prior research into interactions between the human immune system and coronaviruses has identified how these viruses can evade the immune system's protective mechanisms. We also explore systems-level research into the regulatory and proteomic effects of SARS-CoV-2 infection and the immune response. Understanding the structure and behavior of the virus serves to contextualize the many facets of the COVID-19 pandemic and can influence efforts to control the virus and treat the disease.
COVID-19 involves a number of organ systems and can present with a wide range of symptoms. From how the virus infects cells to how it spreads between people, the available research suggests that these patterns are very similar to those seen in the closely related viruses SARS-CoV-1 and possibly Middle East respiratory syndrome-related CoV (MERS-CoV). Understanding the pathogenesis of the SARS-CoV-2 virus also contextualizes how the different biological systems affected by COVID-19 connect. Exploring the structure, phylogeny, and pathogenesis of the virus therefore helps to guide interpretation of the broader impacts of the virus on the human body and on human populations. For this reason, an in-depth exploration of viral mechanisms is critical to a robust understanding of SARS-CoV-2 and, potentially, future emergent human CoVs (HCoVs).
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