Host-microbiota interactions and adaptive immunity

Porphyromonas gingivalis: a potential trigger of neurodegenerative disease

Porphyromonas gingivalis (P. gingivalis) is a gram-negative bacterium and the main causative agent of periodontitis, a disease closely associated with the development of periodontal disease. The progression of periodontitis, a chronic infectious disease, is intricately linked to the inflammatory immune response. Inflammatory cytokines act on periodontal tissues via immunomodulation, resulting in the destruction of the periodontal tissue. Recent studies have established connections between periodontitis and various systemic diseases, including cardiovascular diseases, tumors, and neurodegenerative diseases. Neurodegenerative diseases are neurological disorders caused by immune system dysfunction, including Alzheimer's and Parkinson's diseases. One of the main characteristics of neurodegenerative diseases is an impaired inflammatory response, which mediates neuroinflammation through microglial activation. Some studies have shown an association between periodontitis and neurodegenerative diseases, with P. gingivalis as the primary culprit. P. gingivalis can cross the blood-brain barrier (BBB) or mediate neuroinflammation and injury through a variety of pathways, including the gut-brain axis, thereby affecting neuronal growth and survival and participating in the onset and progression of neurodegenerative diseases. However, comprehensive and systematic summaries of studies on the infectious origin of neurodegenerative diseases are lacking. This article reviews and summarizes the relationship between P. gingivalis and neurodegenerative diseases and its possible regulatory mechanisms. This review offers new perspectives into the understanding of neurodegenerative disease development and highlights innovative approaches for investigating and developing tailored medications for treating neurodegenerative conditions, particularly from the viewpoint of their association with P. gingivalis.

Molecular patterns of microbial and metabolic interactions in septic patients with persistent lymphopenia

BACKGROUND

Persistent lymphopenia can be regarded as an important index of acquired immune dysfunction in sepsis. Whether the specific immune factor changes in septic patients with lymphopenia and the correlation to gut microbiota and metabolites remain unclear.

METHODS

This single-center prospective observation conducted lymphocyte subgroup analysis of blood samples and 16S rRNA gene amplicons sequencing and untargeted metabolomics analysis of fecal samples from 36 subjects with the persistent (≥3d) (n = 21) and non-persistent lymphopenia (<3d) (n = 15).

RESULTS

The persistent lymphopenia showed higher the 28d mortality and 90d mortality, while significantly lower CD3+T/LY, CD3+T cells, CD3+CD4+T cells, CD3+CD8+T cells, Th1 cells, Th2 cells, CD45RA + Treg cells. The 16S rRNA results showed that Staphylococcus, Peptostreptococcus, Bulleidia, Leuconostoc were significant enriched in the persistent lymphopenia. The metabolomics analysis showed that α-Ketoisovaleric acid was increased and 7-DHCA, α-MCA, β-MCA, HCA, LCA-3S, CA, UCA and Citramalic acid were decreased in the persistent lymphopenia.

CONCLUSION

In the process of interaction between host receptors and gut microbiota in patients with persistent lymphopenia sepsis, with a significant reduction in gut microbiota diversity and bile acid metabolites. That can affect various inflammatory pathways of gut immune cells, causing immune dysfunction in the body, which may be one of the main causes of death.

A review of the pathogenesis of epilepsy based on the microbiota-gut-brain-axis theory

The pathogenesis of epilepsy is related to the microbiota-gut-brain axis, but the mechanism has not been clarified. The microbiota-gut-brain axis is divided into the microbiota-gut-brain axis (upward pathways) and the brain-gut-microbiota axis (downward pathways) according to the direction of conduction. Gut microorganisms are involved in pathological and physiological processes in the human body and participate in epileptogenesis through neurological, immunological, endocrine, and metabolic pathways, as well as through the gut barrier and blood brain barrier mediated upward pathways. After epilepsy, the downward pathway mediated by the HPA axis and autonomic nerves triggers "leaky brain "and "leaky gut," resulting in the formation of microbial structures and enterobacterial metabolites associated with epileptogenicity, re-initiating seizures via the upward pathway. Characteristic changes in microbial and metabolic pathways in the gut of epileptic patients provide new targets for clinical prevention and treatment of epilepsy through the upward pathway. Based on these changes, this review further redescribes the pathogenesis of epilepsy and provides a new direction for its prevention and treatment.

Bacterial pneumonia patients with elevated globulin levels did not get infected with SARS-CoV-2: two case reports

Background

COVID-19 began in December 2019, rapidly spreading worldwide. China implemented a dynamic zero-COVID strategy and strict control measures after the outbreak. However, Guangzhou city ended closed-off management by the end of November 2022, leading to exposure to SARS-CoV-2. Despite most hospitalized patients being infected or co-infected with SARS-CoV-2, some remained uninfected. We report two cases of bacterial pneumonia with elevated globulin levels not infected with SARS-CoV-2, aiming to identify protection factors of SARS-CoV-2 infection and provide a scientific basis for SARS-CoV-2 prevention.

Case presentation

Case 1, a 92-year-old male, admitted on October 21, 2022, developed worsening cough and sputum after aspiration, diagnosed with bacterial pneumonia with Pseudomonas aeruginosa, Escherichia coli (CRE) and carbapenem-resistant Acinetobacter baumannii (CRAB) infections. He was treated with imipenem anti-infective therapy and mechanical ventilation, then switched to a combination of meropenem, voriconazole and amikacin anti-infective therapy due to recurrent infections and septic shock, and died of sepsis on 8 January 2023. Case 2 is an 82-year-old male admitted on 30 September 2022, with recurrent cough, sputum, and shortness of breath, diagnosed with bacterial pneumonia with carbapenem-resistant Klebsiella pneumoniae (CRKP) and Mycobacterium pneumoniae infections. He was treated with ventilator-assisted ventilation, meropenem, amikacin, tigecycline and mucomycin nebulization and discharged with improvement on 26 October. He was readmitted on 21 November 2022 and diagnosed with bacterial pneumonia. He was treated with cefoperazone sulbactam, amikacin, meropenem and fluconazole and discharged on 31 December. Neither patient was infected with SARS-CoV-2 during hospitalization. Notably, their globulin levels were elevated before SARS-CoV-2 exposure, gradually decreasing afterward.

Conclusions

Patients with bacterial pneumonia with high globulin levels likely have large amounts of immunoglobulin, and that immunoglobulin cross-reactivity causes this protein to be involved in clearing SARS-CoV-2 and preventing infection. Therefore, bacterial pneumonia patients with high globulin levels included in this study were not infected with SARS-CoV-2. After exposure to SARS-CoV-2, the amount of globulin in the patient's body was reduced because it was used to clear SARS-CoV-2. The results of this study are expected to provide a theoretical basis for the study of the mechanism of prevention and treatment of SARS-CoV-2 infection.

Comprehensive analysis of the gut microbiota in patients with chronic obstructive pulmonary disease of varying severity-A prospective, observational study

Accumulating evidence has highlighted the influence of the gut microbiota on lung immunity. We examined the effects of changes in intestinal microecology on the development of Chronic Obstructive Pulmonary Disease (COPD) and identified microbial biomarkers for acute exacerbations of COPD (AECOPD). Fecal samples were collected from 30 patients with stable COPD, 30 patients with AECOPD, and 10 healthy individuals. Fecal microbiological profiles were analyzed using 16S rRNA gene sequencing. The results showed a distinct difference in the bacterial community composition between the AECOPD, COPD, and healthy control groups. The COPD and AECOPD groups had higher levels of Firmicutes but lower levels of Bacteroidetes compared to the healthy control group at the phylum level. At the genus level, there was an increased abundance of Lachnoclostridium, Alistipes, Streptococcus, and Prevotella in COPD and AECOPD patients. Increasing levels of Lachnoclostridium and Prevotella may indicate an acute exacerbation of COPD. This study identified specific microbial biomarkers associated with AECOPD and characterized the composition of gut microbiota in patients with AECOPD.

Effects of the commensal microbiota on spleen and mesenteric lymph node immune function: investigation in a germ-free piglet model

Commensal microbial-host interaction is crucial for host metabolism, growth, development, and immunity. However, research on microbial-host immunity in large animal models has been limited. This study was conducted to investigate the effects of the commensal microbiota on immune function in two model groups: germ-free (GF) and specific-pathogen-free (SPF) piglets. The weight and organ index of the spleen of the GF piglet were larger than those in the SPF piglet (P < 0.05). The histological structure of the red pulp area and mean area of germinal centers were larger in the SPF piglet than in the GF piglet (P < 0.05), whereas the areas of staining of B cells and T cells in the spleen and mesenteric lymph nodes (MLNs) were lower in the GF piglet (P < 0.05). We identified immune-related genes in the spleen and MLNs using RNA sequencing, and used real-time quantitative PCR to analyze the expression of core genes identified in gene set enrichment analysis. The expression levels of genes in the transforming growth factor-β/SMAD3 signaling pathway, Toll-like receptor 2/MyD88/nuclear factor-κB signaling pathway, and pro-inflammatory factor genes IL-6 and TNF-α in the spleen and MLNs were higher in the SPF piglet and in splenic lymphocytes compared with those in the GF and control group, respectively, under treatment with acetic acid, propionic acid, butyric acid, lipopolysaccharide (LPS), or concanavalin A (ConA). The abundances of plasma cells, CD8++ T cells, follicular helper T cells, and resting natural killer cells in the spleen and MLNs were significantly greater in the SPF piglet than in the GF piglet (P < 0.05). In conclusion, the commensal microbiota influenced the immune tissue structure, abundances of immune cells, and expression of immune-related pathways, indicating the importance of the commensal microbiota for spleen and MLNs development and function. In our study, GF piglet was used as the research model, eliminating the interference of microbiota in the experiment, and providing a suitable and efficient large animal research model for exploring the mechanism of "microbial-host" interactions.

Screening, Identification, and Probiotic Properties of Bacillus Pumilus From Yak

The yak has a unique physiological structure suited to life in anoxic and cold environments at high altitudes. The aim of this study was to isolate Bacillus species with good probiotic properties from yak feces. A series of tests were performed on the isolated Bacillus: 16S rRNA identification, antibacterial activity, tolerance to gastroenteric fluid, hydrophobicity, auto-aggregation, antibiotic sensitivity, growth performance, antioxidants, and immune indexes. A safe and harmless Bacillus pumilus DX24 strain with good survival rate, hydrophobicity, auto-aggregation, and antibacterial activity was identified in the yak feces. Feeding mice with Bacillus pumilus DX24 increased their daily weight gain, jejunal villus length, villi/Crypt ratio, blood IgG levels, and jejunum sIgA levels. This study confirmed the probiotic effects of Bacillus pumilus isolated from yak feces and provides the theoretical basis for the clinical application and development of new feed additives.

The Role of the Vagus Nerve in the Microbiome and Digestive System in Relation to Epilepsy

The Enteric Nervous System (ENS) is described as a division of the Peripheral Nervous System (PNS), located within the gut wall and it is formed by two main plexuses: the myenteric plexus (Auerbach's) and the submucosal plexus (Meissner's). The contribution of the ENS to the pathophysiology of various neurological diseases such as Parkinson's or Alzheimer's disease has been described in the literature, while some other studies have found a connection between epilepsy and the gastrointestinal tract. The above could be explained by cholinergic neurons and neurotransmission systems in the myenteric and submucosal plexuses, regulating the vagal excitability effect. It is also understandable, as the discharges arising in the amygdala are transmitted to the intestine through projections the dorsal motor nucleus of the vagus, giving rise to efferent fibers that stimulate the gastrointestinal tract and consequently the symptoms at this level. Therefore, this review's main objective is to argue in favor of the existing relationship of the ENS with the Central Nervous System (CNS) as a facilitator of epileptogenic or ictogenic mechanisms. The gut microbiota also participates in this interaction; however, it depends on many individual factors of each human being. The link between the ENS and the CNS is a poorly studied epileptogenic site with a big impact on one of the most prevalent neurological conditions such as epilepsy.

Refined fiber inulin promotes inflammation-associated colon tumorigenesis by modulating microbial succinate production

BACKGROUND AND AIM

There is an increased risk of colon cancer associated with inflammatory bowel disease (IBD). Dietary fibers (DFs) naturally present in vegetables and whole grains offer numerous beneficial effects on intestinal health. However, the effects of refined DFs on intestinal health remain unclear. Therefore, we elucidated the impact of the refined DF inulin on colonic inflammation and tumorigenesis.

METHODS

Four-week-old wild-type (WT) mice were fed diets containing insoluble DF cellulose (control) or refined DF inulin for 4 weeks. A subgroup of mice was then switched to drinking water containing dextran sulfate sodium (DSS, 1.4% wt/vol) for colitis induction. In another subgroup of mice, colitis-associated colorectal cancer (CRC) was initiated with three 7-day alternate cycles of DSS following an initial dose of mutagenic substance azoxymethane (AOM; 7.5 mg/kg body weight; i.p.). Post 7 weeks of AOM treatment, mice were euthanized and examined for CRC development.

RESULTS

Mice consuming inulin-containing diet exhibited severe colitis upon DSS administration, as evidenced by more body weight loss, rectal bleeding, and increased colonic inflammation than the DSS-treated control group. Correspondingly, histological analysis revealed extensive disruption of colon architecture and massive infiltration of immune cells in the inulin-fed group. We next examined the effect of inulin on CRC development. Surprisingly, significant mortality (~50%) was observed in the inulin-fed but not in the control group during the DSS cycle. Consequently, the remaining inulin-fed mice, which completed the study exhibited extensive colon tumorigenesis. Immunohistochemical characterization showed comparatively high expression of the cell proliferation marker Ki67 and activation of the Wnt signaling in tumor sections obtained from the inulin-fed group. Gut microbiota and metabolite analysis revealed expansion of succinate producers and elevated cecal succinate in inulin-fed mice. Human colorectal carcinoma cells (HCT116) proliferated more rapidly when supplemented with succinate in an inflamed environment, suggesting that elevated luminal succinate may contribute to tumorigenesis.

CONCLUSIONS

Our study uncovers that supplementation of diet with refined inulin induces abnormal succinate accumulation in the intestinal lumen, which in part contributes to promoting colon inflammation and tumorigenesis.

The microbiome-gut-brain axis in epilepsy: pharmacotherapeutic target from bench evidence for potential bedside applications

The gut-brain axis augments the bidirectional communication between the gut and brain and modulates gut homeostasis and the central nervous system through the hypothalamic-pituitary-adrenal axis, enteroendocrine system, neuroendocrine system, inflammatory and immune pathways. Preclinical and clinical reports showed that gut dysbiosis might play a major regulatory role in neurological diseases such as epilepsy, Parkinson's, multiple sclerosis, and Alzheimer's disease. Epilepsy is a chronic neurological disease that causes recurrent and unprovoked seizures, and numerous risk factors are implicated in developing epilepsy. Advanced consideration of the gut-microbiota-brain axis can reduce ambiguity about epilepsy pathology, antiepileptic drugs, and effective therapeutic targets. Gut microbiota sequencing analysis reported that the level of Proteobacteria, Verrucomicrobia, Fusobacteria, and Firmicutes was increased and the level of Actinobacteria and Bacteroidetes was decreased in epilepsy patients. Clinical and preclinical studies also indicated that probiotics, ketogenic diet, faecal microbiota transplantation, and antibiotics can improve gut dysbiosis and alleviate seizure by enhancing the abundance of healthy biota. This study aims to give an overview of the connection between gut microbiota, and epilepsy, how gut microbiome changes may cause epilepsy, and whether gut microbiome restoration could be used as a treatment for epilepsy.

Microbiota-gut-brain axis and ketogenic diet: how close are we to tackling epilepsy?

The microbiota-gut-brain axis refers to the intricate bidirectional communication between commensal microorganisms residing in the digestive tract and the central nervous system, along neuroendocrine, metabolic, immune, and inflammatory pathways. This axis has been suggested to play a role in several neurological disorders, such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, and epilepsy, paving the way for microbiome-based intervention strategies for the mitigation and treatment of symptoms. Epilepsy is a multifaceted neurological condition affecting more than 50 million individuals worldwide, 30% of whom do not respond to conventional pharmacological therapies. Among the first-hand microbiota modulation strategies, nutritional interventions represent an easily applicable option in both clinical and home settings. In this narrative review, we summarize the mechanisms underlying the microbiota-gut-brain axis involvement in epilepsy, discuss the impact of antiepileptic drugs on the gut microbiome, and then the impact of a particular dietary pattern, the ketogenic diet, on the microbiota-gut-brain axis in epileptic patients. The investigation of the microbiota response to non-pharmacological therapies is an ever-expanding field with the potential to allow the design of increasingly accessible and successful intervention strategies.

Arula-7 powder improves diarrhea and intestinal epithelial tight junction function associated with its regulation of intestinal flora in calves infected with pathogenic Escherichia coli O1

BACKGROUND

The effects of Arula-7 powder (ASP) on diarrhea and intestinal barrier function associated with its regulation of intestinal microflora in calves infected with pathogenic Escherichia coli O1 (E. coli O1) were studied.

METHOD

Twenty Holstein calves were randomly divided into four treatment groups: normal control (NC), model control (MC), 0.5 mg/kg ciprofloxacin (CIP) and 2.50 g/kg ASP groups.

RESULTS

ASP inhibited the relative abundance of Proteobacteria, Selenomonadales, and Enterobacteriales, and increased the relative abundance of Lactobacillus, Faecalibacterium, and Alloprevotella. Moreover, we demonstrated for the first time that the ASP and CIP promoted weight gain, reduced the diarrhea rate (P < 0.05), and enhanced antioxidant capacity (P < 0.05) due to the increase in average daily gain (ADG), total protein (TP), and albumin (ALB). In addition, ASP and CIP increased the expression of Zunola occludens-1 (ZO-1), Occludin, and Claudin-1 in the ileum (P < 0.05), and improved immunity due to increase levels of interleukin-2 (IL-2), interleukin-4 (IL-4), interferon-γ (IFN-γ), immunoglobulin A (IgA), and immunoglobulin G (IgG) in the serum, strengthened CD4+T levels in the ileal mucosa and reducing CD8+T and CD11c+T (P < 0.05).

CONCLUSION

Hence, The intestinal microbiota environment formed by early intervention of ASP powder has a protective effect on the intestinal mucosal function of calves infected with pathogenic E. coli. Video Abstract.

Diet- and salinity-induced modifications of the gut microbiota are associated with differential physiological responses to ranavirus infection in Rana sylvatica

Greater knowledge of how host-microbiome interactions vary with anthropogenic environmental change and influence pathogenic infections is needed to better understand stress-mediated disease outcomes. We investigated how increasing salinization in freshwaters (e.g. due to road de-icing salt runoff) and associated increases in growth of nutritional algae influenced gut bacterial assembly, host physiology and responses to ranavirus exposure in larval wood frogs (Rana sylvatica). Elevating salinity and supplementing a basic larval diet with algae increased larval growth and also increased ranavirus loads. However, larvae given algae did not exhibit elevated kidney corticosterone levels, accelerated development or weight loss post-infection, whereas larvae fed a basic diet did. Thus, algal supplementation reversed a potentially maladaptive stress response to infection observed in prior studies in this system. Algae supplementation also reduced gut bacterial diversity. Notably, we observed higher relative abundances of Firmicutes in treatments with algae-a pattern consistent with increased growth and fat deposition in mammals-that may contribute to the diminished stress responses to infection via regulation of host metabolism and endocrine function. Our study informs mechanistic hypotheses about the role of microbiome mediation of host responses to infection that can be tested in future experiments in this host-pathogen system. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.

Avenues within the gut-liver-brain axis linking chronic liver disease and symptoms

Symptoms of fatigue, social withdrawal and mood disturbances are commonly encountered in patients with chronic liver disease and have a detrimental effect on patient quality of life. Treatment options for these symptoms are limited and a current area of unmet medical need. In this review, we will evaluate the potential mechanistic avenues within the gut-liver-brain axis that may be altered in the setting of chronic liver disease that drive the development of these symptoms. Both clinical and pre-clinical studies will be highlighted as we discuss how perturbations in host immune response, microbiome, neural responses, and metabolites composition can affect the central nervous system.

Role of the Gut Microbiome in Diabetes and Cardiovascular Diseases Including Restoration and Targeting Approaches- A Review

Metabolic diseases, including cardiovascular diseases (CVD) and diabetes, have become the leading cause of morbidity and mortality worldwide. Gut microbiota appears to play a vital role in human disease and health, according to recent scientific reports. The gut microbiota plays an important role in sustaining host physiology and homeostasis by creating a cross-talk between the host and microbiome via metabolites obtained from the host's diet. Drug developers and clinicians rely heavily on therapies that target the microbiota in the management of metabolic diseases, and the gut microbiota is considered the biggest immune organ in the human body. They are highly associated with intestinal immunity and systemic metabolic disorders like CVD and diabetes and are reflected as potential therapeutic targets for the management of metabolic diseases. This review discusses the mechanism and interrelation between the gut microbiome and metabolic disorders. It also highlights the role of the gut microbiome and microbially derived metabolites in the pathophysiological effects related to CVD and diabetes. It also spotlights the reasons that lead to alterations of microbiota composition and the prominence of gut microbiota restoration and targeting approaches as effective treatment strategies in diabetes and CVD. Future research should focus onunderstanding the functional level of some specific microbial pathways that help maintain physiological homeostasis, multi-omics, and develop novel therapeutic strategies that intervene with the gut microbiome for the prevention of CVD and diabetes that contribute to a patient's well-being.

Invariant natural killer T cells minimally influence gut microbiota composition in mice

Invariant Natural Killer T (iNKT) cells are unconventional T cells that respond to glycolipid antigens found in microbes in a CD1d-dependent manner. iNKT cells exert innate-like functions and produce copious amounts of cytokines, chemokines and cytotoxic molecules within only minutes of activation. As such, iNKT cells can fuel or dampen inflammation in a context-dependent manner. In addition, iNKT cells provide potent immunity against bacteria, viruses, parasites and fungi. Although microbiota-iNKT cell interactions are not well-characterized, mounting evidence suggests that microbiota colonization early in life impacts iNKT cell homeostasis and functions in disease. In this study, we showed that CD1d^-/- and Vα14 Tg mice, which lack and have increased numbers of iNKT cells, respectively, had no significant alterations in gut microbiota composition compared to their littermate controls. Furthermore, specific iNKT cell activation by glycolipid antigens only resulted in a transient and minimal shift in microbiota composition when compared to the natural drift found in our colony. Our findings demonstrate that iNKT cells have little to no influence in regulating commensal bacteria at steady state.Abbreviations: iNKT: invariant Natural Killer T cell; αGC: α-galactosylceramide.

Dysregulation of intestinal flora: excess prepackaged soluble fibers damage the mucus layer and induce intestinal inflammation

Soluble fiber is commonly used as a dietary supplement to improve intestinal flora, and many prepackaged products are sold in the market. However, whether these prepared soluble fibers are harmless for intestinal flora has not been systematically evaluated. Here, we assessed the dose-effect of fructooligosaccharides (FOSs) on obesity and intestinal flora using a mouse model. Gavage of low- and medium-dose FOS improved the microbiota in high-fat diet fed mice, but high-dose FOS leads to intestinal flatulence, diarrhea and flora disorders, including an increase in Akkermansia muciniphila and Clostridium difficile, which disrupt the mucus barrier and cause intestinal inflammation. Besides, a high dose of xylooligosaccharide by gavage induces symptoms similar to those of FOS in mice. These adverse effects can be alleviated by regulating intestinal flora. In addition, we experimentally proved that supplementary probiotics protect against the negative effects of FOS in obese mice. Therefore, prepackaged soluble fiber supplements need to be taken with caution, and excessive consumption of soluble fibers results in intestinal dysfunction and even induces intestinal inflammation. Combining probiotics and soluble fiber can be considered if necessary.

Effect of sea cucumber peptides on the immune response and gut microbiota composition in ovalbumin-induced allergic mice

The prevalence of food allergies has increased in Asian countries. The aim of this study was to determine the potential value of sea cucumber peptide (SCP) for anti-allergic therapeutics in terms of their effect on immune response and gut microbiota composition. Results exhibited that SCP could significantly improve the allergy symptoms caused by ovalbumin and could reduce the risk of IgE mediated allergic disorders, as well as repair the morphological damage in the colon. Flow cytometry analysis indicated that SCP could improve the ratio of CD4+/CD8+ T lymphocytes. 16S rRNA results indicated that SCP could differently impact the composition of microbiota. The relative abundances of Bacteroidetes and Firmicutes and the Bacteroidetes/Firmicutes ratio were altered in normal mice. When compared with the OVA treated group, the SCP treated groups showed an increase in the relative abundance of Lachnospiraceae, Muribaculaceae and Ruminococcaceae, and a decrease in Bacteroidaceae, Prevotellaceae, and Lactobacillaceae. These results demonstrate that SCP exhibits potential antiallergic activities in a mouse model of ovalbumin allergy by regulating intestinal microbiota diversity and upregulating the immune response of T lymphocyte subpopulations, which might provide important evidence that SCP can be developed into a novel functional food for inhibiting ovalbumin allergy.

Microbiome in cancer: Role in carcinogenesis and impact in therapeutic strategies

Cancer is the world's second-leading cause of death, and the involvement of microbes in a range of diseases, including cancer, is well established. The gut microbiota is known to play an important role in the host's health and physiology. The gut microbiota and its metabolites may activate immunological and cellular pathways that kill invading pathogens and initiate a cancer-fighting immune response. Cancer is a multiplex illness, characterized by the persistence of several genetic and physiological anomalies in malignant tissue, complicating disease therapy and control. Humans have coevolved with a complex bacterial, fungal, and viral microbiome over millions of years. Specific long-known epidemiological links between certain bacteria and cancer have recently been grasped at the molecular level. Similarly, advances in next-generation sequencing technology have enabled detailed research of microbiomes, such as the human gut microbiome, allowing for the finding of taxonomic and metabolomic linkages between the microbiome and cancer. These investigations have found causative pathways for both microorganisms within tumors and bacteria in various host habitats far from tumors using direct and immunological procedures. Anticancer diagnostic and therapeutic solutions could be developed using this review to tackle the threat of anti-cancer medication resistance as well through the wide-ranging involvement of the microbiota in regulating host metabolic and immunological homeostasis. We reviewed the significance of gut microbiota in cancer initiation as well as cancer prevention. We look at certain microorganisms that may play a role in the development of cancer. Several bacteria with probiotic qualities may be employed as bio-therapeutic agents to re-establish the microbial population and trigger a strong immune response to remove malignancies, and further study into this should be conducted.

Dietary κ-carrageenan facilitates gut microbiota-mediated intestinal inflammation

The inflammatory effects of carrageenan (CGN), a ubiquitous food additive, remains controversial. Gut microbiota and intestinal homeostasis may be a breakthrough in resolving this controversy. Here we show that, κ-CGN did not cause significant inflammatory symptoms, but it did cause reduced bacteria-derived short-chain fatty acids (SCFAs) and decreased thickness of the mucus layer by altering microbiota composition. Administration of the pathogenic bacterium Citrobacter rodentium, further aggravated the inflammation and mucosal damage in the presence of κ-CGN. Mucus layer degradation and altered SCFA levels could be reproduced by fecal transplantation from κ-CGN-fed mice, but not from germ-free κ-CGN-fed mice. These symptoms could be partially repaired by administering probiotics. Our results suggest that κ-CGN may not be directly inflammatory, but it creates an environment that favors inflammation by perturbation of gut microbiota composition and then facilitates expansion of pathogens, and this effect may be partially reversed by the introduction of probiotics.

Treatment of inflammatory bowel disease: Potential effect of NMN on intestinal barrier and gut microbiota

Nicotinamide mononucleotide (NMN) exerts physiological effects in mammals through its conversion to nicotinamide adenine dinucleotide (NAD⁺). In this study, we established experimental models of colitis by mixing drinking water of C57BL/6J mice with dextran sodium sulphate (DSS), and then fed them with the same concentration of NMN or at the same time. After NMN treatment, we observed improved morphology of inflamed intestines, slightly restored length of colon, improved barrier function and reduced proinflammatory factors expression in serum. Also, significant alterations in the composition and abundance of intestinal flora in IBD mice were found. The abundance of Firmicutes, Verrucomicrobia, Akkermansia and Lactobacillus, considered as beneficial bacteria, increased, while Bacteroidetes and Muribaculaceae unclassifiably decreased. Taken together, these results suggest that NMN may improve intestinal inflammation, reduce intestinal mucosal permeability and repair gut flora dysbiosis in IBD.

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After NMN feeding, the improved morphology of inflamed intestines, restored length of colon and enhanced mucosal permeability were discovered.

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The expression of pro-inflammatory factors in serum was also decreased after NMN administration.

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Significant alterations in the composition and abundance of intestinal flora in IBD mice were found.

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This study provides some evidences for the application of NMN in the prevention and treatment of IBD, which is important for clinical application.

Porphyromonas gingivalis-Induced Cognitive Impairment Is Associated With Gut Dysbiosis, Neuroinflammation, and Glymphatic Dysfunction

Background

Periodontal pathogen and gut microbiota are closely associated with the pathogenesis of Alzheimer's disease (AD). Porphyromonas gingivalis (Pg), the keystone periodontal pathogen, can induce cognitive impairment. The gut has a connection and communication with the brain, which is an important aspect of the gut-brain axis (GBA). In the present study, we investigate whether Pg induces cognitive impairment through disturbing the GBA.

Methods

In this study, Pg was orally administered to mice, three times a week for 1 month. The effects of Pg administration on the gut and brain were evaluated through behaviors, gut microbiota, immune cells, glymphatic pathway clearance, and neuroinflammation.

Results

Pg induced cognitive impairment and dysbiosis of gut microbiota. The α-diversity parameters did not show significant change after Pg administration. The β-diversity demonstrated that the gut microbiota compositions were different between the Pg-administered and control groups. At the species level, the Pg group displayed a lower abundance of Parabacteroides gordonii and Ruminococcus callidus than the control group, but a higher abundance of Mucispirillum schaedleri. The proportions of lymphocytes in the periphery and myeloid cells infiltrating the brain were increased in Pg-treated animals. In addition, the solute clearance efficiency of the glymphatic system decreased. Neurons in the hippocampus and cortex regions were reduced in mice treated with Pg. Microglia, astrocytes, and apoptotic cells were increased. Furthermore, amyloid plaque appeared in the hippocampus and cortex regions in Pg-treated mice.

Conclusions

These findings indicate that Pg may play an important role in gut dysbiosis, neuroinflammation, and glymphatic system impairment, which may in turn lead to cognitive impairment.

Application of phage display for T-cell receptor discovery

The immune system is tasked to keep our body unharmed and healthy. In the immune system, B- and T-lymphocytes are the two main components working together to stop and eliminate invading threats like virus particles, bacteria, fungi and parasite from attacking our healthy cells. The function of antibodies is relatively more direct in target recognition as compared to T-cell receptors (TCR) which recognizes antigenic peptides being presented on the major histocompatibility complex (MHC). Although phage display has been widely applied for antibody presentation, this is the opposite in the case of TCR. The cell surface TCR is a relatively large and complex molecule, making presentation on phage surfaces challenging. Even so, recombinant versions and modifications have been introduced to allow the growing development of TCR in phage display. In addition, the increasing application of TCR for immunotherapy has made it an important binding motif to be developed by phage display. This review will emphasize on the application of phage display for TCR discovery as well as the engineering aspect of TCR for improved characteristics.

The role of microbiota in respiratory health and diseases, particularly in tuberculosis

Trillions of beneficial and hostile microorganisms live in the human respiratory and gastrointestinal tracts, which act as gatekeepers in maintaining human health, i.e., protecting the body from pathogens by colonizing mucosal surfaces with microbiota-derived antimicrobial metabolites such as short-chain fatty acids or host-derived cytokines and chemokines. It is widely accepted that the microbiome interacts with each other and with the host in a mutually beneficial relationship. Microbiota in the respiratory tract may also play a crucial role in immune homeostasis, maturation, and maintenance of respiratory physiology. Anti-TB antibiotics may cause dysbiosis in the lung and intestinal microbiota, affecting colonization resistance and making the host more susceptible to Mycobacterium tuberculosis (M. tuberculosis) infection. This review discusses recent advances in our understanding of the lung microbiota composition, the lungs and intestinal microbiota related to respiratory health and diseases, microbiome sequencing and analysis, the bloodstream, and the lymphatic system that underpin the gut-lung axis in M. tuberculosis-infected humans and animals. We also discuss the gut-lung axis interactions with the immune system, the role of the microbiome in TB pathogenesis, and the impact of anti-TB antibiotic therapy on the microbiota in animals, humans, and drug-resistant TB individuals.

Microbiota-Gut-Brain Axis and Epilepsy: A Review on Mechanisms and Potential Therapeutics

The gut-brain axis refers to the bidirectional communication between the gut and brain, and regulates intestinal homeostasis and the central nervous system via neural networks and neuroendocrine, immune, and inflammatory pathways. The development of sequencing technology has evidenced the key regulatory role of the gut microbiota in several neurological disorders, including Parkinson's disease, Alzheimer's disease, and multiple sclerosis. Epilepsy is a complex disease with multiple risk factors that affect more than 50 million people worldwide; nearly 30% of patients with epilepsy cannot be controlled with drugs. Interestingly, patients with inflammatory bowel disease are more susceptible to epilepsy, and a ketogenic diet is an effective treatment for patients with intractable epilepsy. Based on these clinical facts, the role of the microbiome and the gut-brain axis in epilepsy cannot be ignored. In this review, we discuss the relationship between the gut microbiota and epilepsy, summarize the possible pathogenic mechanisms of epilepsy from the perspective of the microbiota gut-brain axis, and discuss novel therapies targeting the gut microbiota. A better understanding of the role of the microbiota in the gut-brain axis, especially the intestinal one, would help investigate the mechanism, diagnosis, prognosis evaluation, and treatment of intractable epilepsy.

Cross Talk between Gut Microbiota and Intestinal Mucosal Immunity in the Development of Ulcerative Colitis

Ulcerative colitis (UC), a nonspecific inflammatory disease, is characterized by inflammation and mucosal damage in the colon, and its prevalence in the world is increasing. Nevertheless, the exact pathogenesis of UC is still unclear. Accumulating data have suggested that its pathogenesis is multifactorial, involving genetic predisposition, environmental factors, microbial dysbiosis, and dysregulated immune responses. Generally, UC is aroused by inappropriate immune activation based on the interaction of host and intestinal microbiota. The relationship between microbiota and host immune system in the pathogenesis of UC is complicated. However, increasing evidence indicates that the shift of microbiota composition can substantially influence intestinal immunity. In this review, we primarily focus on the delicate balance between microbiota and gut mucosal immunity during UC progression.

Gut microbiome and thyroid autoimmunity

Intestinal microbiota gained attention due to its pleiotropic effect on intestinal barrier, nutrients metabolism and on immune system development and functions. Recent evidence pointed out a possible role of an altered gut microbiota composition in the pathogenesis and progression of several autoimmune disorders, occurring at gastrointestinal level or far apart. In thyroid autoimmune disorders, encompassing Hashimoto's thyroiditis, Graves' disease and thyroid-associated orbitopathy, the combined effect of environmental triggers and genetic predisposing background, lead to the loss of self-tolerance and to auto-aggressive damage, involving both cellular and humoral networks of immune system. This review is aimed at assessing the current knowledge about the studies published on the fecal microbiota composition in patients bearing thyroid autoimmune diseases. We further examined the reciprocal interaction between gut microbiota composition and the most used treatments for thyroid disorders.

Microbiome-immune interactions in tuberculosis

Tuberculosis (TB) remains an infectious disease of global significance and a leading cause of death in low- and middle-income countries. Significant effort has been directed towards understanding Mycobacterium tuberculosis genomics, virulence, and pathophysiology within the framework of Koch postulates. More recently, the advent of “-omics” approaches has broadened our appreciation of how “commensal” microbes have coevolved with their host and have a central role in shaping health and susceptibility to disease. It is now clear that there is a diverse repertoire of interactions between the microbiota and host immune responses that can either sustain or disrupt homeostasis. In the context of the global efforts to combatting TB, such findings and knowledge have raised important questions: Does microbiome composition indicate or determine susceptibility or resistance to M. tuberculosis infection? Is the development of active disease or latent infection upon M. tuberculosis exposure influenced by the microbiome? Does microbiome composition influence TB therapy outcome and risk of reinfection with M. tuberculosis? Can the microbiome be actively managed to reduce risk of M. tuberculosis infection or recurrence of TB? Here, we explore these questions with a particular focus on microbiome-immune interactions that may affect TB susceptibility, manifestation and progression, the long-term implications of anti-TB therapy, as well as the potential of the host microbiome as target for clinical manipulation.

Inhibition of PD-1 Protects against TNBS-Induced Colitis via Alteration of Enteric Microbiota

METHODS

Colitis was induced in mice using 2,4,6-trinitrobenzene-sulfonic acid (TNBS), and mice were subsequently treated with either a PD-1 inhibitor or 5-amino-salicylic acid (ASA) as a positive control. Body weight, disease activity index (DAI), colon length, and tissue damage were evaluated, and the enteric microbiota was profiled using high-throughput 16S rRNA sequencing of fecal samples from the experimental mice.

RESULTS

TNBS caused mice to experience IBD-like symptoms, which were attenuated by the PD-1 inhibitor, as indicated by a decrease in DAI scores (p = 0.0002). Furthermore, in this mouse model of IBD, PD-1 inhibition improved the alpha diversity as well as restored the beta diversity of the enteric microbiome. It also significantly enriched the abundance of short-chain fatty acid- (SCFA-) producing bacteria of the Firmicutes (p < 0.05) and Bacteroidetes (p < 0.05) phyla but depopulated Proteobacteria (p < 0.05).

CONCLUSION

PD-1 inhibition can partly mitigate TNBS-induced colitis and restore the enteric microbiota by enriching the abundance of SCFA-producing bacteria.

The Gut-Brain Axis: How Microbiota and Host Inflammasome Influence Brain Physiology and Pathology

The human microbiota has a fundamental role in host physiology and pathology. Gut microbial alteration, also known as dysbiosis, is a condition associated not only with gastrointestinal disorders but also with diseases affecting other distal organs. Recently it became evident that the intestinal bacteria can affect the central nervous system (CNS) physiology and inflammation. The nervous system and the gastrointestinal tract are communicating through a bidirectional network of signaling pathways called the gut-brain axis, which consists of multiple connections, including the vagus nerve, the immune system, and bacterial metabolites and products. During dysbiosis, these pathways are dysregulated and associated with altered permeability of the blood-brain barrier (BBB) and neuroinflammation. However, numerous mechanisms behind the impact of the gut microbiota in neuro-development and -pathogenesis remain poorly understood. There are several immune pathways involved in CNS homeostasis and inflammation. Among those, the inflammasome pathway has been linked to neuroinflammatory conditions such as multiple sclerosis, Alzheimer's and Parkinson's diseases, but also anxiety and depressive-like disorders. The inflammasome complex assembles upon cell activation due to exposure to microbes, danger signals, or stress and lead to the production of pro-inflammatory cytokines (interleukin-1β and interleukin-18) and to pyroptosis. Evidences suggest that there is a reciprocal influence of microbiota and inflammasome activation in the brain. However, how this influence is precisely working is yet to be discovered. Herein, we discuss the status of the knowledge and the open questions in the field focusing on the function of intestinal microbial metabolites or products on CNS cells during healthy and inflammatory conditions, such as multiple sclerosis, Alzheimer's and Parkinson's diseases, and also neuropsychiatric disorders. In particular, we focus on the innate inflammasome pathway as immune mechanism that can be involved in several of these conditions, upon exposure to certain microbes.

Microbiome in cancer progression and therapy

A myriad of microbes living together with the host constitute microbiota, which possesses very diverse functions in regulation of host physiology. Recently, it has been unequivocally demonstrated that microbiota regulates cancer initiation, progression and responses to therapy. Here we review known pro-tumorigenic and anti-tumorigenic function of microbiota and mechanisms how microbes can regulate cancer cells and immune and stromal cells within the tumor microenvironment.

Pancreatic Diseases and Microbiota: A Literature Review and Future Perspectives

Gut microbiota represent an interesting worldwide research area. Several studies confirm that microbiota has a key role in human diseases, both intestinal (such as inflammatory bowel disease, celiac disease, intestinal infectious diseases, irritable bowel syndrome) and extra intestinal disorders (such as autism, multiple sclerosis, rheumatologic diseases). Nowadays, it is possible to manipulate microbiota by administering prebiotics, probiotics or synbiotics, through fecal microbiota transplantation in selected cases. In this scenario, pancreatic disorders might be influenced by gut microbiota and this relationship could be an innovative and inspiring field of research. However, data are still scarce and controversial. Microbiota manipulation could represent an important therapeutic strategy in the pancreatic diseases, in addition to standard therapies. In this review, we analyze current knowledge about correlation between gut microbiota and pancreatic diseases, by discussing on the one hand existing data and on the other hand future possible perspectives.

The dialogue between unconventional T cells and the microbiota

The mammalian immune system is equipped with unconventional T cells that respond to microbial molecules such as glycolipids and small-molecule metabolites, which are invisible to conventional CD4 and CD8 T cells. Unconventional T cells include invariant natural killer T (iNKT) cells and mucosa-associated invariant T (MAIT) cells, which are involved in a wide range of infectious and non-infectious diseases, such as cancer and autoimmunity. In addition, their high conservation across mammals, their restriction by non-polymorphic antigen-presenting molecules, and their immediate and robust responses make these 'innate' T cells appealing targets for the development of one-size-fits-all immunotherapies. In this review, we discuss how iNKT and MAIT cells directly and indirectly detect the presence of and respond to pathogenic and commensal microbes. We also explore the current understanding of the bidirectional relationship between the microbiota and innate T cells, and how this crosstalk shapes the immune response in disease.

Comprehensive Analysis of Serum and Fecal Bile Acid Profiles and Interaction with Gut Microbiota in Primary Biliary Cholangitis

Accumulation of bile acids (BAs) contributes significantly to the pathogenesis of primary biliary cholangitis (PBC). Here, we sought to systematically characterize the serum and fecal BA profiles and the linkage between BAs and gut microbiota in PBC. The serum and fecal BAs were compared between 65 UDCA treatment-naive PBC and 109 healthy controls using UPLC-MS in cross-sectional study. In a prospective study, a subgroup of patients was enrolled for BA and microbiota analysis before and after UDCA therapy. BA compositions in serum and feces significantly differed between treatment-naive PBC and controls. Particularly, PBC was associated with decreased conversions of conjugated to unconjugated, and primary to secondary BAs, indicating impaired microbial metabolism of BAs. PBC patients at advanced stage exhibited a more abnormal BA profile compared with early-stage patients. UDCA treatment led to a decreased level of taurine-conjugated BAs, thereby reversing the conjugated/unconjugated ratio in PBC. Moreover, the level of secondary BAs such as DCA and conjugated DCA inversely correlated with PBC-enriched gut microbes (e.g., Veillonella, Klebsiella), while positively correlated with control-enriched microbes (e.g., Faecalibacterium, Oscillospira). Microbiota analysis also revealed a significant increase of taurine-metabolizing bacteria Bilophila spp. in patients after UDCA, which was strongly correlated with decreased taurine-conjugated BAs. In addition, serum FGF19 was remarkably increased in treatment-naïve PBC and decreased after UDCA. Our study established specific alterations of BA compositions in serum and feces of PBC, suggesting the potential for using BAs for diagnosis, and highlighting the possibility of modulating BA profile by altering gut microbiota. Graphical Abstract.

Early life disruption of the microbiota affects organ development and cytokine gene expression in threespine stickleback

The microbiota that inhabits vertebrates exerts strong effects on host physiology and can be crucial to the development of a normal phenotype. This includes development of the immune system, somatic growth and maintenance, and morphogenesis. However, the genetic background of the host can also affect these life history traits. To this end, we investigated the effects of the microbiota on growth, development, and immune gene expression on two populations of threespine stickleback (Gasterosteus aculeatus), one anadromous and one freshwater. We tested the hypotheses that microbial colonization and the genetic background of the host would affect survival, cytokine gene expression, growth, and development. We raised in vitro crosses of stickleback larvae with and without conventional microbiota. We then exposed all these treatments to Vibrio anguillarum, a potential fish pathogen, in a full factorial design. We found stickleback raised without conventional microbiota had smaller swim bladders relative to those raised with conventional microbiota. Stickleback raised with conventional microbiota exhibited small increases in cytokine gene expression. We found no differences in growth or survival regardless of treatment. These results are consistent with other investigations that show microbiota disruption, in early life, can alter host organ and tissue development and immune responses.

Bacteria-immune cells dialog and the homeostasis of the systems

The dialog between microbes and immune cells is critical for the establishment and maintenance of immune homeostasis. Bacterial-derived metabolites or structural components initiate immune signaling pathways and transcriptional factors, inducing a broad range of specificities and functional repertoires of the immune cells. Conversely, the immune system regulates the composition and function of bacterial communities. Elements of the adaptive immunity, including maternal antibodies and mucosal antibody responses, play crucial roles in protecting the hosts from pathogens in addition to promoting colonization of symbiotic bacteria at mucosal surfaces. The complex interactions set from an early stage in life between the microbiota and adaptive immunity, impact other major physiological systems. In this review, we summarize recent advances in our understanding of how gut bacteria regulate systemic homeostasis by highlighting the finely orchestrated interactions between gut bacteria, immune responses and the nervous system.

Gut microbiota maturation during early human life induces enterocyte proliferation via microbial metabolites

BACKGROUND

The intestinal tract undergoes a period of cellular maturation during early life, primarily characterized by the organization of epithelial cells into specialized crypt and villus structures. These processes are in part mediated by the acquisition of microbes. Infants delivered at term typically harbor a stable, low diversity microbiota characterized by an overrepresentation of various Bacilli spp., while pre-term infants are colonized by an assortment of bacteria during the first several weeks after delivery. However, the functional effects of these changes on intestinal epithelium homeostasis and maturation remain unclear. To study these effects, human neonate feces were obtained from term and pre-term infants. Fecal 16S rDNA sequencing and global untargeted LC-MS were performed to characterize microbial composition and metabolites from each population. Murine enteral organoids (enteroids) were cultured with 0.22 μm filtered stool supernatant pooled from term or pre-term infants.

RESULTS

Term and pre-term microbial communities differed significantly from each other by principle components analysis (PCoA, PERMANOVA p < 0.001), with the pre-term microbiome characterized by increased OTU diversity (Wilcox test p < 0.01). Term communities were less diverse and dominated by Bacilli (81.54%). Pre-term stools had an increased abundance of vitamins, amino acid derivatives and unconjugated bile acids. Pathway analysis revealed a significant increase in multiple metabolic pathways in pre-term samples mapped to E. coli using the KEGG database related to the fermentation of various amino acids and vitamin biosynthesis. Enteroids cultured with supernatant from pre-term stools proliferated at a higher rate than those cultured with supernatant from term stools (cell viability: 207% vs. 147.7%, p < 0.01), grew larger (area: 81,189μm2 vs. 41,777μm2, p < 0.001), and bud at a higher rate (6.5 vs. 4, p < 0.01). Additionally, genes involved in stem cell proliferation were upregulated in pre-term stool treated enteroid cultures (Lgr5, Ephb2, Ascl2 Sox9) but not term stool treated enteroids.

CONCLUSIONS

Our findings indicate that microbial metabolites from the more diverse gut microbiome associated with pre-term infants facilitate stem cell proliferation. Therefore, perturbations of the pre-term microbiota may impair intestinal homeostasis.

Rethinking mucosal antibody responses: IgM, IgG and IgD join IgA

Humoral immune responses at mucosal surfaces have historically focused on IgA. Growing evidence highlights the complexity of IgA-inducing pathways and the functional impact of IgA on mucosal commensal bacteria. In the gut, IgA contributes to the establishment of a mutualistic host-microbiota relationship that is required to maintain homeostasis and prevent disease. This Review discusses how mucosal IgA responses occur in an increasingly complex humoral defence network that also encompasses IgM, IgG and IgD. Aside from integrating the protective functions of IgA, these hitherto neglected mucosal antibodies may strengthen the communication between mucosal and systemic immune compartments.

The Plasticity of Newly Formed B Cells

Newly formed B cells (NF-B cells) that emerge from the bone marrow to the periphery have often been referred to as immature or transitional B cells. However, NF-B cells have several striking characteristics, including a distinct BCR repertoire, high expression of AID, high sensitivity to PAMPs, and the ability to produce cytokines. A number of findings do not support their designation as immature because NF-B cells have the potential to become Ab-producing cells and to undergo class-switch recombination. In this review, we provide a fresh perspective on NF-B cell functions and describe some of the signals driving their activation. We summarize growing evidence supporting a role for NF-B cells in protection against infections and as a potential source of autoantibody-producing cells in autoimmune diseases such as systemic lupus erythematosus.

Recent advances in intestinal alkaline phosphatase, inflammation, and nutrition

In recent years, much new data on intestinal alkaline phosphatase (IAP) have been published, and major breakthroughs have been disclosed. The aim of the present review is to critically analyze the publications released over the last 5 years. These breakthroughs include, for example, the direct implication of IAP in intestinal tight junction integrity and barrier function maintenance; chronic intestinal challenge with low concentrations of Salmonella generating long-lasting depletion of IAP and increased susceptibility to inflammation; the suggestion that genetic mutations in the IAP gene in humans contribute to some forms of chronic inflammatory diseases and loss of functional IAP along the gut and in stools; stool IAP as an early biomarker of incipient diabetes in humans; and omega-3 fatty acids as direct inducers of IAP in intestinal tissue. Many recent papers have also explored the prophylactic and therapeutic potential of IAP and other alkaline phosphatase (AP) isoforms in various experimental settings and diseases. Remarkably, nearly all data confirm the potent anti-inflammatory properties of (I)AP and the negative consequences of its inhibition on health. A simplified model of the body AP system integrating the IAP compartment is provided. Finally, the list of nutrients and food components stimulating IAP has continued to grow, thus emphasizing nutrition as a potent lever for limiting inflammation.

Perfect timing: circadian rhythms, sleep, and immunity - an NIH workshop summary

Recent discoveries demonstrate a critical role for circadian rhythms and sleep in immune system homeostasis. Both innate and adaptive immune responses - ranging from leukocyte mobilization, trafficking, and chemotaxis to cytokine release and T cell differentiation -are mediated in a time of day-dependent manner. The National Institutes of Health (NIH) recently sponsored an interdisciplinary workshop, "Sleep Insufficiency, Circadian Misalignment, and the Immune Response," to highlight new research linking sleep and circadian biology to immune function and to identify areas of high translational potential. This Review summarizes topics discussed and highlights immediate opportunities for delineating clinically relevant connections among biological rhythms, sleep, and immune regulation.

Demystifying the manipulation of host immunity, metabolism, and extraintestinal tumors by the gut microbiome

The trillions of microorganisms in the gut microbiome have attracted much attention recently owing to their sophisticated and widespread impacts on numerous aspects of host pathophysiology. Remarkable progress in large-scale sequencing and mass spectrometry has increased our understanding of the influence of the microbiome and/or its metabolites on the onset and progression of extraintestinal cancers and the efficacy of cancer immunotherapy. Given the plasticity in microbial composition and function, microbial-based therapeutic interventions, including dietary modulation, prebiotics, and probiotics, as well as fecal microbial transplantation, potentially permit the development of novel strategies for cancer therapy to improve clinical outcomes. Herein, we summarize the latest evidence on the involvement of the gut microbiome in host immunity and metabolism, the effects of the microbiome on extraintestinal cancers and the immune response, and strategies to modulate the gut microbiome, and we discuss ongoing studies and future areas of research that deserve focused research efforts.

Associations between Monocyte and T Cell Cytokine Profiles in Autism Spectrum Disorders: Effects of Dysregulated Innate Immune Responses on Adaptive Responses to Recall Antigens in a Subset of ASD Children

Changes in monocyte cytokine production with toll like receptor (TLR) agonists in subjects with autism spectrum disorders (ASD) were best reflected by the IL-1β/IL-10 ratios in our previous research. The IL-1β/IL-10 based subgrouping (low, normal, and high) of ASD samples revealed marked differences in microRNA expression, and mitochondrial respiration. However, it is unknown whether the IL-1β/IL-10 ratio based subgrouping is associated with changes in T cell cytokine profiles or monocyte cytokine profiles with non-TLR agonists. In ASD (n = 152) and non-ASD (n = 41) subjects, cytokine production by peripheral blood monocytes (PBMo) with TLR agonists and β-glucan, an inflammasome agonist, and T cell cytokine production by peripheral blood mononuclear cells (PBMCs) with recall antigens (Ags) (food and candida Ags) were concurrently measured. Changes in monocyte cytokine profiles were observed with β-glucan in the IL-1β/IL-10 ratio based ASD subgroups, along with changes in T cell cytokine production and ASD subgroup-specific correlations between T cell and monocyte cytokine production. Non-ASD controls revealed considerably less of such correlations. Altered innate immune responses in a subset of ASD children are not restricted to TLR pathways and correlated with changes in T cell cytokine production. Altered trained immunity may play a role in the above described changes.

The Costs of Living Together: Immune Responses to the Microbiota and Chronic Gut Inflammation

While the vertebrate microbiota is critical to the normal function of many host traits, hosts may expend a large amount of energy to constrain and interface with their microbiota via their immune system to avoid the high fitness costs associated with gut dysbiosis, pathobionts, and opportunistic pathogens. All jawed vertebrates share mucosal immunity dedicated to isolating the microbiota, and a breakdown of this system can result in chronic gut inflammation. In humans, chronic gut inflammation negatively affects growth and development. There is little information available on the prevalence of chronic gut inflammation in wild animals, but given that animals with different life histories emphasize different immune responses, it follows that wild animals may vary in their susceptibility to chronic gut inflammation, and most animals will experience signaling that can lead to this state. These can be top-down signals originating from sources like the central nervous system or bottom-up signals originating from changes in the gut microbiota. The sources of these signals might include stress, developmental transitions, food restriction, and dietary shifts. Here, we briefly discuss host-microbiota interactions from the perspective of life history theory and ecoimmunology, focusing on the mucosal immune system and chronic gut inflammation. We also include future directions for research and the tools necessary to investigate them.

Oral Administration of Compound Probiotics Improved Canine Feed Intake, Weight Gain, Immunity and Intestinal Microbiota

Probiotics have been used successfully to promote human and animal health, but only limited studies have focused on using probiotics to improve the health of hosts of different age. Canine microbiome studies may be predictive of results in humans because of the high structural and functional similarity between dog and human microbiomes. A total of 90 dogs were divided into three groups based on dog age (elderly group, n = 30; young group, n = 24; and training group, n = 36). Each group was subdivided into two subgroups, with and without receiving daily probiotic feed additive. The probiotic feed additive contained three different bacterial strains, namely Lactobacillus casei Zhang, Lactobacillus plantarum P-8, and Bifdobacterium animalis subsp. lactis V9. Serum and fecal samples were collected and analyzed at four different time points, i.e., days 0, 30, and 60 of probiotic treatment, and 15 days after ceasing probiotic treatment. The results demonstrated that probiotics significantly promoted the average daily feed intake of the elderly dogs (P < 0.01) and the average daily weight gain of all dogs (P < 0.05), enhanced the level of serum IgG (P < 0.001), IFN-α (P < 0.05), and fecal SIgA (P < 0.001), while reduced the TNF-α (P < 0.05). Additionally, probiotics could change the gut microbial structure of elderly dogs and significantly increased beneficial bacteria (including some Lactobacillus species and Faecalibacterium prausnitzii) and decreased potentially harmful bacteria (including Escherichia coli and Sutterella stercoricanisin), and the elderly dogs showed the strongest response to the probiotics; the relative abundance of some of these species correlated with certain immune factors and physiological parameters, suggesting that the probiotic treatment improved the host health and enhanced the host immunity by stimulating antibody and cytokine secretion through regulating canine gut microbiota. Furthermore, the gut microbiota of the elderly dogs shifted toward a younger-like composition at day 60 of probiotic treatment. Our findings suggested that the probiotic treatment effects on canine health and immunity were age-related and have provided interesting insights into future development of probiotic-based strategies to improve animal and human health.

Loading ceftriaxone, vancomycin, and Bifidobacteria bifidum TMC3115 to neonatal mice could differently and consequently affect intestinal microbiota and immunity in adulthood

Recent studies have demonstrated that antibiotics/or probiotics administration in early life play key roles on modulating intestinal microbiota and the alterations might cause long-lasting consequences both physiologically and immunologically. We investigated the effects of early life ceftriaxone, vancomycin and Bifidobacterium bifidum TMC3115 (TMC3115) treatment on intestinal microbiota and immunity both in neonates and adults even after termination of antibiotics exposure. We found that ceftriaxone and vancomycin, but not TMC3115, significantly altered the intestinal microbiota, serum total IgE level, and the morphology and function of the intestinal epithelium in the neonatal mice. In the adult stages, the diversity and composition of the intestinal microbiota were significantly different in the antibiotic-treated mice, and ceftriaxone-treated mice exhibited significantly higher serum total IgE and OVA-specific IgE levels. TMC3115 significantly mitigated the alteration of intestinal microbiota caused by ceftriaxone not vancomycin. Antibiotics and TMC3115 can differently modulate intestinal microbiota and SCFAs metabolism, affecting the development and function of the immunity and intestinal epithelium to different degrees in neonatal mice. Neonatal ceftriaxone-induced abnormal intestinal microbiota, immunity and epithelium could last to adulthood partly, which might be associated with the enhancement of host susceptibility to IgE-mediated allergies and related immune responses, TMC3115 may protect against the side effects of antibiotic treatment, at least partly.