Enteric Delivery of Regenerating Family Member 3 alpha Alters the Intestinal Microbiota and Controls Inflammation in Mice With Colitis

CXCR2, as a key regulatory gene of HDP-PG-1, maintains intestinal mucosal homeostasis

The intestine defends against pathogenic microbial invasion via the secretion of host defense peptides (HDPs). Nutritional immunomodulation can stimulate the expression of endogenous HDPs and enhance the body's immune defense, representing a novel non-antibiotic strategy for disease prevention. The project aims to explore the regulatory mechanism of protegrin-1 (PG-1) expression using sodium phenylbutyrate (PBA) by omics sequencing technology and further investigate the role of key regulatory genes on intestinal health. The results showed that PBA promoted PG-1 expression in intestinal epithelial cells based on cell density through epidermal growth factor receptor (EGFR) and G protein-coupled receptor (GPR43). Transcriptome sequencing and microRNA sequencing revealed that C-X-C motif chemokine receptor 2 (CXCR2) exhibited interactions with PG-1. Pre-treatment cells with a CXCR2 inhibitor (SB225002) effectively suppressed the induction of PG-1 by PBA. Furthermore, SB225002 significantly suppressed the gene expression of HDPs in the jejunum of mice without influencing on the morphology, number of goblet cells, and proliferation of the intestine. CXCR2 inhibition significantly reduced the expression of HDPs during E. coli infection, and resulted in the edema of jejunal epithelial cells. The 16S rDNA analysis of cecal contents showed that the E. coli and SB225002 treatments changed gut microbiota diversity and composition at different taxonomic levels. Correlation analysis suggested a potential regulatory relationship between gut microbiota and HDPs. To that end, a gene involved in the HDP expression, CXCR2, has been identified in the study, which contributes to improving intestinal immune function. PBA may be used as a functional additive to regulate intestinal mucosal function, thereby enhancing the health of the intestinal and host.

Population pharmacokinetics and pharmacodynamics of efmarodocokin alfa (IL-22Fc)

Efmarodocokin alfa (IL-22Fc) is a fusion protein of human IL-22 linked to the crystallizable fragment (Fc) of human IgG4. It has been tested in multiple indications including inflammatory bowel disease (IBD). The purposes of the present analyses were to describe the population pharmacokinetics (PK) of efmarodocokin alfa and perform pharmacodynamic (PD) analysis on the longitudinal changes of the PD biomarker REG3A after efmarodocokin alfa treatment as well as identify covariates that affect efmarodocokin alfa PK and REG3A PD. The data used for this analysis included 182 subjects treated with efmarodocokin alfa in two clinical studies. The population PK and PD analyses were conducted sequentially. Efmarodocokin alfa concentration-time data were analyzed using a nonlinear mixed-effects modeling approach, and an indirect response model was adopted to describe the REG3A PD data with efmarodocokin alfa serum concentration linked to the increase in REG3A. The analysis software used were NONMEM and R. A 3-compartment model with linear elimination best described the PK of efmarodocokin alfa. The estimated population-typical value for clearance (CL) was 1.12 L/day, and volume of central compartment was 6.15 L. Efmarodocokin alfa CL increased with higher baseline body weight, C-reactive protein, and CL was 27.6% higher in IBD patients compared to healthy subjects. The indirect response PD model adequately described the longitudinal changes of REG3A after efmarodocokin alfa treatment. A popPK and PD model for efmarodocokin alfa and REG3A was developed and covariates affecting the PK and PD were identified.

Intestinal melatonin levels and gut microbiota homeostasis are independent of the pineal gland in pigs

Introduction

Melatonin (MEL) is a crucial neuroendocrine hormone primarily produced by the pineal gland. Pinealectomy (PINX) has been performed on an endogenous MEL deficiency model to investigate the functions of pineal MEL and its relationship with various diseases. However, the effect of PINX on the gastrointestinal tract (GIT) MEL levels and gut microbiome in pigs has not been previously reported.

Methods

By using a newly established pig PINX model, we detected the levels of MEL in the GIT by liquid chromatography-tandem mass spectrometry. In addition, we examined the effects of PINX on the expression of MEL synthesis enzymes, intestinal histomorphology, and the intestinal barrier. Furthermore, 16S rRNA sequencing was performed to analyze the colonic microbiome.

Results

PINX reduced serum MEL levels but did not affect GIT MEL levels. Conversely, MEL supplementation increased MEL levels in the GIT and intestinal contents. Neither PINX nor MEL supplementation had any effect on weight gain, organ coefficient, serum biochemical indexes, or MEL synthetase arylalkylamine N-acetyltransferase (AANAT) expression in the duodenum, ileum, and colon. Furthermore, no significant differences were observed in the intestinal morphology or intestinal mucosal barrier function due to the treatments. Additionally, 16S rRNA sequencing revealed that PINX had no significant impact on the composition of the intestinal microbiota. Nevertheless, MEL supplementation decreased the abundance of Fibrobacterota and increased the abundance of Actinobacteriota, Desulfobacterota, and Chloroflexi.

Conclusion

We demonstrated that synthesis of MEL in the GIT is independent of the pineal gland. PINX had no influence on intestinal MEL level and microbiota composition in pigs, while exogenous MEL alters the structure of the gut microbiota.

Evidence that the loss of colonic anti-microbial peptides may promote dysbiotic Gram-negative inflammaging-associated bacteria in aging mice

Introduction: Aging studies in humans and mice have played a key role in understanding the intestinal microbiome and an increased abundance of "inflammaging" Gram-negative (Gn) bacteria. The mechanisms underlying this inflammatory profile in the aging microbiome are unknown. We tested the hypothesis that an aging-related decrease in colonic crypt epithelial cell anti-microbial peptide (AMP) gene expression could promote colonic microbiome inflammatory Gn dysbiosis and inflammaging. Methods: As a model of aging, C57BL/6J mice fecal (colonic) microbiota (16S) and isolated colonic crypt epithelial cell gene expression (RNA-seq) were assessed at 2 months (mth) (human: 18 years old; yo), 15 mth (human: 50 yo), and 25 mth (human: 84 yo). Informatics examined aging-related microbial compositions, differential colonic crypt epithelial cell gene expressions, and correlations between colonic bacteria and colonic crypt epithelial cell gene expressions. Results: Fecal microbiota exhibited significantly increased relative abundances of pro-inflammatory Gn bacteria with aging. Colonic crypt epithelial cell gene expression analysis showed significant age-related downregulation of key AMP genes that repress the growth of Gn bacteria. The aging-related decrease in AMP gene expressions is significantly correlated with an increased abundance in Gn bacteria (dysbiosis), loss of colonic barrier gene expression, and senescence- and inflammation-related gene expression. Conclusion: This study supports the proposed model that aging-related loss of colonic crypt epithelial cell AMP gene expression promotes increased relative abundances of Gn inflammaging-associated bacteria and gene expression markers of colonic inflammaging. These data may support new targets for aging-related therapies based on intestinal genes and microbiomes.

The gut microbiota contributes to the infection of bovine viral diarrhea virus in mice

Bovine viral diarrhea virus (BVDV) is prevalent worldwide and causes significant economic losses. Gut microbiota is a large microbial community and has a variety of biological functions. However, whether there is a correlation between gut microbiota and BVDV infection and what kind of relation between them have not been reported. Here, we found that gut microbiota composition changed in normal mice after infecting with BVDV, but mainly the low abundance microbe was affected. Interestingly, BVDV infection significantly reduced the diversity of gut microbiota and changed its composition in gut microbiota-dysbiosis mice. Furthermore, compared with normal mice of BVDV infection, there were more viral loads in the duodenum, jejunum, spleen, and liver of the gut microbiota-dysbiosis mice. However, feces microbiota transplantation (FMT) reversed these effects. The data above indicated that the dysbiosis of gut microbiota was a key factor in the high infection rate of BVDV. It is found that the IFN-I signal was involved by investigating the underlying mechanisms. The inhibition of the proliferation and increase in the apoptosis of peripheral blood lymphocytes (PBL) were also observed. However, FMT treatment reversed these changes by regulating PI3K/Akt, ERK, and Caspase-9/Caspase-3 pathways. Furthermore, the involvement of butyrate in the pathogenesis of BVDV was also further confirmed. Our results showed for the first time that gut microbiota acts as a key endogenous defense mechanism against BVDV infection; moreover, targeting regulation of gut microbiota structure and abundance may serve as a new strategy to prevent and control the disease.IMPORTANCEWhether the high infection rate of BVDV is related to gut microbiota has not been reported. In addition, most studies on BVDV focus on in vitro experiments, which limits the study of its prevention and control strategy and its pathogenic mechanism. In this study, we successfully confirmed the causal relationship between gut microbiota and BVDV infection as well as the potential molecular mechanism based on a mouse model of BVDV infection and a mouse model of gut microbiota dysbiosis. Meanwhile, a mouse model which is more susceptible to BVDV provided in this study lays an important foundation for further research on prevention and control strategy of BVDV and its pathogenesis. In addition, the antiviral effect of butyrate, the metabolites of butyrate-producing bacteria, has been further revealed. Overall, our findings provide a promising prevention and control strategy to treat this infectious disease which is distributed worldwide.

Major urinary protein (Mup) gene family deletion drives sex-specific alterations in the house-mouse gut microbiota

The gut microbiota is shaped by host metabolism. In house mice (Mus musculus), major urinary protein (MUP) pheromone production represents a considerable energy investment, particularly in sexually mature males. Deletion of the Mup gene family shifts mouse metabolism toward an anabolic state, marked by lipogenesis, lipid accumulation, and body mass increases. Given the metabolic implications of MUPs, they may also influence the gut microbiota. Here, we investigated the effect of a deletion of the Mup gene family on the gut microbiota of sexually mature mice. Shotgun metagenomics revealed distinct taxonomic and functional profiles between wild-type and knockout males but not females. Deletion of the Mup gene cluster significantly reduced diversity in microbial families and functions in male mice. Additionally, a species of Ruminococcaceae and several microbial functions, such as transporters involved in vitamin B5 acquisition, were significantly depleted in the microbiota of Mup knockout males. Altogether, these results show that MUPs significantly affect the gut microbiota of house mouse in a sex-specific manner.IMPORTANCEThe community of microorganisms that inhabits the gastrointestinal tract can have profound effects on host phenotypes. The gut microbiota is in turn shaped by host genes, including those involved with host metabolism. In adult male house mice, expression of the major urinary protein (Mup) gene cluster represents a substantial energy investment, and deletion of the Mup gene family leads to fat accumulation and weight gain in males. We show that deleting Mup genes also alters the gut microbiota of male, but not female, mice in terms of both taxonomic and functional compositions. Male mice without Mup genes harbored fewer gut bacterial families and reduced abundance of a species of Ruminococcaceae, a family that has been previously shown to reduce obesity risk. Studying the impact of the Mup gene family on the gut microbiota has the potential to reveal the ways in which these genes affect host phenotypes.

Gut microbiota dysbiosis alters chronic pain behaviors in a humanized transgenic mouse model of sickle cell disease

ABSTRACT

Pain is the most common symptom experienced by patients with sickle cell disease (SCD) throughout their lives and is the main cause of hospitalization. Despite the progress that has been made towards understanding the disease pathophysiology, major gaps remain in the knowledge of SCD pain, the transition to chronic pain, and effective pain management. Recent evidence has demonstrated a vital role of gut microbiota in pathophysiological features of SCD. However, the role of gut microbiota in SCD pain is yet to be explored. We sought to evaluate the compositional differences in the gut microbiota of transgenic mice with SCD and nonsickle control mice and investigate the role of gut microbiota in SCD pain by using antibiotic-mediated gut microbiota depletion and fecal material transplantation (FMT). The antibiotic-mediated gut microbiota depletion did not affect evoked pain but significantly attenuated ongoing spontaneous pain in mice with SCD. Fecal material transplantation from mice with SCD to wild-type mice resulted in tactile allodynia (0.95 ± 0.17 g vs 0.08 ± 0.02 g, von Frey test, P < 0.001), heat hyperalgesia (15.10 ± 0.79 seconds vs 8.68 ± 1.17 seconds, radiant heat, P < 0.01), cold allodynia (2.75 ± 0.26 seconds vs 1.68 ± 0.08 seconds, dry ice test, P < 0.01), and anxiety-like behaviors (Elevated Plus Maze Test, Open Field Test). On the contrary, reshaping gut microbiota of mice with SCD with FMT from WT mice resulted in reduced tactile allodynia (0.05 ± 0.01 g vs 0.25 ± 0.03 g, P < 0.001), heat hyperalgesia (5.89 ± 0.67 seconds vs 12.25 ± 0.76 seconds, P < 0.001), and anxiety-like behaviors. These findings provide insights into the relationship between gut microbiota dysbiosis and pain in SCD, highlighting the importance of gut microbial communities that may serve as potential targets for novel pain interventions.

Hybrid nutraceutical of 2-ketoglutaric acid in improving inflammatory bowel disease: Role of prebiotics and TAK1 inhibitor

The main cause of inflammatory bowel disease (IBD) is abnormal intestinal permeability due to the disruption of the tight junction of the intestinal barrier through a pathogen-mediated inflammatory mechanism and an imbalance of the gut microbiota. This study aimed to evaluate whether 2-ketoglutaric acid alleviated permeability dysfunction with tight junction localization, activated the transforming growth factor beta-activated kinase 1 (TAK1) inflammation pathway, and regulated the homeostasis of the intestinal microbiome in vitro and in vivo IBD model. Our findings revealed that 2-ketoglutaric acid significantly suppressed abnormal intestinal permeability, delocalization of tight junction proteins from the intestinal cell, expression of inflammatory cytokines, such as TNF-α, both in vitro and in vivo. 2-Ketoglutaric acid was found to directly bind to TAK1 and inhibit the TNF receptor-associated factor 6 (TRAF6)-TAK1 interaction, which is related to the activation of nuclear factor kappa B (NF-κB) pathways, thereby regulating the expression of mitogen-activated protein kinase. Dietary 2-ketoglutaric acid also alleviated gut microbiota dysbiosis and IBD symptoms, as demonstrated by improvements in the intestine length and the abundance of Ligilactobacillus, Coriobacteriaceae_UCG_002, and Ruminococcaceae_unclassified in mice with colitis. This study indicated that 2-ketoglutaric acid binds to TAK1 for activity inhibition which is related to the NF-κB pathway and alleviates abnormal permeability by regulating tight junction localization and gut microbiome homeostasis. Therefore, 2-ketoglutaric acid is an effective nutraceutical agent and prebiotic for the treatment of IBD.

A Comparative Analysis of the Stomach, Gut, and Lung Microbiomes in Rattus norvegicus

Urban rats serve as reservoirs for several zoonotic pathogens that seriously endanger public health, destroy stored food, and damage infrastructure due to their close interaction with humans and domestic animals. Here, we characterize the core microbiomes of R. norvegicus's stomach, gut, and lung using 16S rRNA next-generation Illumina HiSeq sequencing. The USEARCH software (v11) assigned the dataset to operational taxonomic units (OTUs). The alpha diversity index was calculated using QIIME1, while the beta diversity index was determined using the Bray-Curtis and Euclidean distances between groups. Principal component analyses visualized variation across samples based on the OTU information using the R package. Linear discriminant analysis, effect sizes (LEfSe), and phylogenetic investigation were used to identify differentially abundant taxa among groups. We reported an abundance of microbiota in the stomach, and they shared some of them with the gut and lung microbiota. A close look at the microbial family level reveals abundant Lactobacillaceae and Bifidobacteriaceae in the stomach, whereas Lactobacillaceae and Erysipelotrichaceae were more abundant in the gut; in contrast, Alcaligenaceae were abundant in the lungs. At the species level, some beneficial bacteria, particularly Lactobacillus reuteri and Lactobacillus johnsonii, and some potential pathogens, such as Bordetella hinzii, Streptococcus parauberis, Porphyromonas pogonae, Clostridium perfringens, etc., were identified in stomach, gut, and lung samples. Moreover, the alpha and beta diversity indexes revealed significant differences between the groups. Further analysis revealed abundant differential taxonomic biomarkers, i.e., increased Prevotellaceae and Clostridia in the lungs, whereas Campylobacteria and Lachnospirales were richest in the stomachs. In conclusion, we identified many beneficial, opportunistic, and highly pathogenic bacteria, confirming the importance of urban rats for public health. This study recommends a routine survey program to monitor rodent distribution and the pathogens they carry and transmit to humans and other domestic mammals.

Antimicrobial overproduction sustains intestinal inflammation by inhibiting Enterococcus colonization

Loss of antimicrobial proteins such as REG3 family members compromises the integrity of the intestinal barrier. Here, we demonstrate that overproduction of REG3 proteins can also be detrimental by reducing a protective species in the microbiota. Patients with inflammatory bowel disease (IBD) experiencing flares displayed heightened levels of secreted REG3 proteins that mediated depletion of Enterococcus faecium (Efm) from the gut microbiota. Efm inoculation of mice ameliorated intestinal inflammation through activation of the innate immune receptor NOD2, which was associated with the bacterial DL-endopeptidase SagA that generates NOD2-stimulating muropeptides. NOD2 activation in myeloid cells induced interleukin-1β (IL-1β) secretion to increase the proportion of IL-22-producing CD4+ T helper cells and innate lymphoid cells that promote tissue repair. Finally, Efm was unable to protect mice carrying a NOD2 gene variant commonly found in IBD patients. Our findings demonstrate that inflammation self-perpetuates by causing aberrant antimicrobial activity that disrupts symbiotic relationships with gut microbes.

Decoding the IBD paradox: A triadic interplay between REG3, enterococci, and NOD2

In this issue of Cell Host & Microbe, Jang et al. decode an intriguing paradox: excessive antimicrobial peptide-regenerating family member 3 (REG3) expression in inflammatory bowel disease (IBD) patients depletes protective enterococci. This depletion impairs the NOD2 anti-inflammatory pathway and perpetuates inflammation, thus providing insight into IBD pathogenesis.

Daphnetin attenuates intestinal inflammation, oxidative stress, and apoptosis in ulcerative colitis via inhibiting REG3A-dependent JAK2/STAT3 signaling pathway

Daphnetin is a natural coumarin compound with anti-inflammatory, anti-oxidant, and anti-apoptotic effects, which has been previously demonstrated to ameliorate DSS-induced ulcerative colitis (UC). However, the molecular mechanism involved in the daphnetin-mediated pathological process of UC remains unclarified. The current study used DSS-induced mice and LPS-challenged Caco-2 cells as UC models. Bodyweight, disease activity index (DAI) score, and colon length were used to evaluate the severity of colitis. The histological changes in colon tissues were observed using H&E and PAS staining. Protein levels were detected by western blot. The malondialdehyde (MDA) and superoxide dismutase (SOD) activities were used to assess oxidative stress. Inflammatory responses were evaluated by detecting the levels of inflammatory cytokines (IFN-r, IL-1β, IL-6, and TNF-α) using flow cytometry. CCK-8 and TUNEL assay were employed to determine cell growth and cell death, respectively. The results showed that daphnetin could ameliorate the severity of colitis and attenuate the damage to intestinal structure in DSS-induced mice. Compared with the DSS group, the expression of ZO-1, occludin, and anti-apoptotic protein (BCL-2) was increased while the level of pro-apoptotic proteins (Bax and cleaved caspase 3) was decreased in DSS + daphnetin group. The activity of MDA and SOD, as well as the levels of inflammatory cytokines were substantially suppressed by daphnetin. In consistency, in vitro assays indicated that daphnetin protected Caco-2 cells from LPS-stimulated viability impairment, apoptosis, oxidative stress, and inflammation. Furthermore, daphnetin suppressed the activity of JAK2/STAT signaling in LPS-induced Caco-2 cells in a REG3A-dependent manner. REG3A overexpression abated the ameliorative effects of daphnetin while JAK2/STAT signaling inhibition functioned synergically with daphnetin in LPS-stimulated Caco-2 cells. Collectively, this study deepened the understanding of the therapeutic effects of daphnetin on UC and uncovered for the first time that daphnetin functioned through REG3A-activated JAK2/STAT3 signaling in UC, which may provide novel insights for the treatment of UC.

Major urinary protein (Mup) gene family deletion drives sex-specific alterations on the house mouse gut microbiota

The gut microbiota is shaped by host metabolism. In house mice (Mus musculus), major urinary protein (MUP) pheromone production represents a considerable energy investment, particularly in sexually mature males. Deletion of the Mup gene family shifts mouse metabolism towards an anabolic state, marked by lipogenesis, lipid accumulation, and body mass increases. Given the metabolic implications of MUPs, they may also influence the gut microbiota. Here, we investigated the effect of deletion of the Mup gene family on the gut microbiota of sexually mature mice. Shotgun metagenomics revealed distinct taxonomic and functional profiles between wildtype and knockout males, but not females. Deletion of the Mup gene cluster significantly reduced diversity in microbial families and functions in male mice. Additionally, specific taxa of the Ruminococcaceae family, which is associated with gut health and reduced risk of developing metabolic syndrome, and several microbial functions, such as transporters involved in vitamin B5 acquisition, were significantly depleted in the microbiota of Mup-knockout males. Altogether these results show that major urinary proteins significantly affect the gut microbiota of house mouse in a sex-specific manner.

Reg3γ: current understanding and future therapeutic opportunities in metabolic disease

Regenerating family member gamma, Reg3γ (the mouse homolog of human REG3A), belonging to the antimicrobial peptides (AMPs), functions as a part of the host immune system to maintain spatial segregation between the gut bacteria and the host in the intestine via bactericidal activity. There is emerging evidence that gut manipulations such as bariatric surgery, dietary supplementation or drug treatment to produce metabolic benefits alter the gut microbiome. In addition to changes in a wide range of gut hormones, these gut manipulations also induce the expression of Reg3γ in the intestine. Studies over the past decades have revealed that Reg3γ not only plays a role in the gut lumen but can also contribute to host physiology through interaction with the gut microbiota. Herein, we discuss the current knowledge regarding the biology of Reg3γ, its role in various metabolic functions, and new opportunities for therapeutic strategies to treat metabolic disorders.

Plant Polyphenols Attenuate DSS-induced Ulcerative Colitis in Mice via Antioxidation, Anti-inflammation and Microbiota Regulation

The pathogenesis of ulcerative colitis (UC) is associated with inflammation, oxidative stress, and gut microbiota imbalance. Although most researchers have demonstrated the antioxidant bioactivity of the phenolic compounds in plants, their UC-curing ability and underlying mechanisms still need to be further and adequately explored. Herein, we studied the antioxidation-structure relationship of several common polyphenols in plants including gallic acid, proanthocyanidin, ellagic acid, and tannic acid. Furthermore, the in vivo effects of the plant polyphenols on C57BL/6 mice with dextran-sulfate-sodium-induced UC were evaluated and the action mechanisms were explored. Moreover, the interplay of several mechanisms was determined. The higher the number of phenolic hydroxyl groups, the stronger the antioxidant activity. All polyphenols markedly ameliorated the symptoms and pathological progression of UC in mice. Furthermore, inflammatory cytokine levels were decreased and the intestinal barrier was repaired. The process was regulated by the antioxidant-signaling pathway of nuclear-erythroid 2-related factor 2. Moreover, the diversity of the intestinal microbiota, Firmicutes-to-Bacteroides ratio, and relative abundance of beneficial bacteria were increased. An interplay was observed between microbiota regulation and oxidative stress, immunity, and inflammatory response. Furthermore, intestinal barrier repair was found to be correlated with inflammatory responses. Our study results can form a basis for comprehensively developing plant-polyphenol-related medicinal products.

Microbiota-derived short-chain fatty acids and modulation of host-derived peptides formation: Focused on host defense peptides

The byproducts of bacterial fermentation known as short-chain fatty acids (SCFAs) are chemically comprised of a carboxylic acid component and a short hydrocarbon chain. Recent investigations have demonstrated that SCFAs can affect intestinal immunity by inducing endogenous host defense peptides (HDPs) and their beneficial effects on barrier integrity, gut health, energy supply, and inflammation. HDPs, which include defensins, cathelicidins, and C-type lectins, perform a significant function in innate immunity in gastrointestinal mucosal membranes. SCFAs have been demonstrated to stimulate HDP synthesis by intestinal epithelial cells via interactions with G protein-coupled receptor 43 (GPR43), activation of the Jun N-terminal kinase (JNK) and Mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathways, and the cell growth pathways. Furthermore, SCFA butyrate has been demonstrated to enhance the number of HDPs released from macrophages. SCFAs promote monocyte-to-macrophage development and stimulate HDP synthesis in macrophages by inhibiting histone deacetylase (HDAC). Understanding the etiology of many common disorders might be facilitated by studies into the function of microbial metabolites, such as SCFAs, in the molecular regulatory processes of immune responses (e.g., HDP production). This review will focus on the current knowledge of the role and mechanism of microbiota-derived SCFAs in influencing the synthesis of host-derived peptides, particularly HDPs.

The relationship between gut microbiota and inflammatory response, learning and memory in mice by sleep deprivation

Objective

Sleep deprivation has developed into a common phenomenon, which can lead to inflammatory responses and cognitive impairment, but the underlying mechanism is ambiguous. Emerging evidence shows that gut microbiota plays a crucial role in theoccurrence and development of inflammatory and psychiatric diseases, possibly through neuroinflammation and the brain-gut axis. The current study investigated the influence of sleep deprivation on gut microbiota composition, pro-inflammatory cytokines, learning and memory in mice. Further, it explored whether changes in gut microbiota increase pro-inflammatory cytokine and induce learning and memory impairment.

Methods

Healthy 8-week-old male C57BL/6J mice were randomly divided into the regular control group (RC), environmental control group (EC), and sleep deprivation group (SD). The sleep deprivation model was established by the Modified Multiple Platform Method. The experimental mice were subjected to sleep deprivation for 6h/d (8:00 am∼14:00 pm) in a sleep deprivation chamber, and the duration of sleep deprivation was 8 weeks. Morris water maze test to assess learning and memory in mice. Enzyme-Linked Immunosorbent Assay determined the concentrations of inflammatory cytokines. The changes in gut microbiota in mice were analyzed by 16S rRNA sequencing.

Results

We found that SD mice had elevated latency of exploration to reach the hidden platform (p>0.05) and significantly decreased traversing times, swimming distance, and swimming time in the target zone when the hidden platform was removed (p<0.05). Sleep deprivation caused dysregulated expression in serum IL-1β, IL-6, and TNF-α in mice, and the difference was significant (all p<0.001). Tannerellaceae, Rhodospirillales, Alistipes, and Parabacteroides were significantly increased in SD mice. Correlation analysis showed IL-1β was positively correlated with the abundance of Muribaculaceae (r=0.497, p<0.05) and negatively correlated with the abundance of Lachnospiraceae (r=-0.583, p<0.05). The TNF-α was positively correlated with the abundances of Erysipelotrichaceae, Burkholderiaceae, and Tannerellaceae (r=0.492, r=0.646, r=0.726, all p<0.05).

Conclusion

Sleep deprivation can increase pro-inflammatory cytokine responses and learning and memory impairment in mice and may be caused by the disorder of the microbiota. These findings of this study may open avenues for potential interventions that can relieve the detrimental consequences of sleep loss.

Plasma Proteomic Analysis Reveals the Potential Role of Lectin and Alternative Complement Pathways in IgA Vasculitis Pathogenesis

BACKGROUND

IgA vasculitis (IgAV) is the most common form of childhood vasculitis. A better understanding of its pathophysiology is required to identify new potential biomarkers and treatment targets.

OBJECTIVE

to assess the underlying molecular mechanisms in the pathogenesis of IgAV using an untargeted proteomics approach.

METHODS

Thirty-seven IgAV patients and five healthy controls were enrolled. Plasma samples were collected on the day of diagnosis before any treatment was initiated. We used nano-liquid chromatography-tandem mass spectrometry (nLC-MS/MS) to investigate the alterations in plasma proteomic profiles. For the bioinformatics analyses, databases including Uniprot, PANTHER, KEGG, Reactome, Cytoscape, and IntAct were used.

RESULTS

Among the 418 proteins identified in the nLC-MS/MS analysis, 20 had significantly different expressions in IgAV patients. Among them, 15 were upregulated and 5 were downregulated. According to the KEGG pathway and function classification analysis, complement and coagulation cascades were the most enriched pathways. GO analyses showed that the differentially expressed proteins were mainly involved in defense/immunity proteins and the metabolite interconversion enzyme family. We also investigated molecular interactions in the identified 20 proteins of IgAV patients. We extracted 493 interactions from the IntAct database for the 20 proteins and used Cytoscape for the network analyses.

CONCLUSION

Our results clearly suggest the role of the lectin and alternate complement pathways in IgAV. The proteins defined in the pathways of cell adhesion may serve as biomarkers. Further functional studies may lead the way to better understanding of the disease and new therapeutic options for IgAV treatment.

Oral Delivery of Mouse β-Defensin 14 (mBD14)-Producing Lactococcus lactis NZ9000 Attenuates Experimental Colitis in Mice

Antimicrobial peptides (AMPs) play essential roles in maintaining intestinal health and have been suggested as possible therapeutic strategies against inflammatory bowel disease (IBD). However, the instability of AMPs in the process of transmission in vivo limits their application in the treatment of IBD. In this study, we constructed the mBD14-producing Lactococcus lactis NZ9000 (L. lactis/mBD14) to achieve enteric delivery of mBD14 and evaluated its protective effect on dextran sodium sulfate (DSS)-induced colitis. Mice treated with L. lactis/mBD14 exhibited milder symptoms of colitis (P < 0.01). Additionally, L. lactis/mBD14 treatment reversed DSS-induced epithelial dysfunction and reduced the production of pro-inflammatory cytokines in colon (P < 0.01). Mechanistically, L. lactis/mBD14 significantly inhibited NOD-like receptor pyrin domain containing three inflammasome-mediated pro-inflammatory response (P < 0.05) and regulated microbiota homeostasis by promoting the abundance of probiotic bacteria Akkermansia muciniphila and Faecalibacterium prausnitzii and decreasing the pathogenic Escherichia coli (P < 0.01). Taken together, this study demonstrates the protective effect of L. lactis/mBD14 in DSS-induced colitis, and suggests that oral administration of L. lactis/mBD14 may represent a potential therapeutic strategy for IBD.

Jinhong decoction protects sepsis-associated acute lung injury by reducing intestinal bacterial translocation and improving gut microbial homeostasis

Background: Currently no specific treatments are available for sepsis and the associated syndromes including acute lung injury (ALI). Jinhong Decoction (JHD) is a traditional Chinese prescription, and it has been applied clinically as an efficient and safe treatment for sepsis, but the underlying mechanism remains unknown. The aim of the study was to explore the potential mechanisms of JHD ameliorating sepsis and concurrent ALI.

Methods: The cecum ligation puncture (CLP)- induced murine sepsis model was established for determining the efficacy of JHD protecting CLP and ALI. The role of gut microbiota involved in the efficacy of JHD was evaluated by 16S rRNA sequencing and fecal microbiota transplantation (FMT). Translocation of intestinal Escherichia coli (E. coli) to lungs after CLP was verified by qPCR and in vivo-imaging. Intestinal permeability was analyzed by detecting FITC-dextran leakness. Junction proteins were evaluated by Western blotting and immunofluorescence.

Results: JHD treatment remarkably increased survival rate of septic mice and alleviated sepsis-associated lung inflammation and injury. FMT suggested that the protective role for JHD was mediated through the regulation of gut microbiota. We further revealed that JHD administration partially restored the diversity and configuration of microbiome that was distorted by CLP operation. Of interest, the intestinal bacteria, E. coli particularly, was found to translocate into the lungs upon CLP via disrupting the intestinal mucosal barrier, leading to the inflammatory response and tissue damage in lungs. JHD impeded the migration and hence lung accumulation of intestinal E. coli, and thereby prevented severe ALI associated with sepsis. This effect is causatively related with the ability of JHD to restore intestinal barrier by up-regulating tight junctions.

Conclusion: Our study unveils a mechanism whereby the migration of gut bacteria leads to sepsis-associated ALI, and we demonstrate the potential of JHD as an effective strategy to block this bacterial migration for treating sepsis and the associated immunopathology in the distal organs.

Antimicrobial protein REG3A regulates glucose homeostasis and insulin resistance in obese diabetic mice

Innate immune mediators of pathogen clearance, including the secreted C-type lectins REG3 of the antimicrobial peptide (AMP) family, are known to be involved in the regulation of tissue repair and homeostasis. Their role in metabolic homeostasis remains unknown. Here we show that an increase in human REG3A improves glucose and lipid homeostasis in nutritional and genetic mouse models of obesity and type 2 diabetes. Mice overexpressing REG3A in the liver show improved glucose homeostasis, which is reflected in better insulin sensitivity in normal weight and obese states. Delivery of recombinant REG3A protein to leptin-deficient ob/ob mice or wild-type mice on a high-fat diet also improves glucose homeostasis. This is accompanied by reduced oxidative protein damage, increased AMPK phosphorylation and insulin-stimulated glucose uptake in skeletal muscle tissue. Oxidative damage in differentiated C2C12 myotubes is greatly attenuated by REG3A, as is the increase in gp130-mediated AMPK activation. In contrast, Akt-mediated insulin action, which is impaired by oxidative stress, is not restored by REG3A. These data highlight the importance of REG3A in controlling oxidative protein damage involved in energy and metabolic pathways during obesity and diabetes, and provide additional insight into the dual function of host-immune defense and metabolic regulation for AMP.

Mycobacterium potentiates protection from colorectal cancer by gut microbial alterations

Not only are many Mycobacteria pathogens, but they can act as strong non-specific immunopotentiators, generating beneficial effects on the pathogenesis of some diseases. However, there has been no direct evidence of the effect of mycobacterial species on colorectal cancer (CRC). Herein, we showed that there may be a meaningful inverse correlation between the incidence of tuberculosis and CRC based on global statistics and that heat-killed Mycobacterial tuberculosis and live Mycobacterium bovis (Bacillus Calmette-Guérin strain) could ameliorate CRC development. In particular, using a faecal microbiota transplantation and a comparison between separate housing and cohousing, we demonstrated that the gut microbiota is involved in the protective effects. The microbial alterations can be elucidated by the modulation of antimicrobial activities including those of the Reg3 family genes. Furthermore, interleukin-22 production by T helper cells contributed to the anti-inflammatory activity of Mycobacteria. Our results revealed a novel role of Mycobacteria involving gut microbial alterations in dampening inflammation-associated CRC and an immunological mechanism underlying the interaction between microbes and host immunity.

Passion fruit peel and its zymolyte enhance gut function in Sanhuang broilers by improving antioxidation and short-chain fatty acids and decreasing inflammatory cytokines

The passion fruit peel (PFP) is the by-product of juice processing and is rich in phenolic compounds and dietary fibers. As the high ADF content in PFP (34.20%), we proceeded to treat PFP with cellulase. The ADF decreased to 16.70% after enzymatic processing, and we supposed that enzymolytic passion fruit peel (EPF) should have a greater growth performance than PFP to broilers. Two trials were conducted to evaluate the effects of dietary PFP or EPF supplementation on growth performance, serum biochemical indices, meat quality, and cecal short-chain fatty acids, microbiota, and metabolites in broilers. In Exp. 1, 180 1-day-old Sanhuang broilers (male, 36.17 ± 2.47 g) were randomly allocated into 3 treatments, with 6 replicates in each treatment. The 3 experimental diets included 1 basal diet (control) and 2 PFP-added diets supplemented with 1 and 2% PFP, respectively. The trial lasted for 42 d. In Exp. 2, 144 Sanhuang broilers (male, 112-day-old, 1.62 ± 0.21 kg) were randomly allocated to 3 treatments. Each treatment was distributed among 6 pens, and each pen contained 8 broilers. The 3 treatment diets included: a control diet, a positive control diet supplementing 75 mg/kg chlortetracycline, and the experimental diet supplementing 3% EPF. The trial lasted for 56 d. Results showed that dietary 1 and 2% PFP addition did not affect growth performance in Exp. 1, and the 3% EPF supplementation had a negative effect on ADFI (P < 0.05) in Exp. 2. A decreased serum triglyceride (P < 0.05) in broilers was observed in Exp. 1. Broilers fed EPF had a higher glutathione peroxidase (GSH-Px) (P < 0.05), and lower levels of tumor necrosis factor-α (TNF-α) (P < 0.05) and glucose (P < 0.05) in Exp. 2. We also found that broilers from PFP or EPF-treated treatments had an increased butyrate content and higher microbial diversity in the cecum. The effects of antioxidation, anti-inflammatory function, and elevated SCFAs were confirmed after the microbe and untargeted metabolomic analysis. Dietary EPF supplementation significantly increased the SCFA-generating bacteria, anti-inflammatory-related bacteria, the antioxidant-related and anti-inflammatory-related metabolites. Moreover, dietary 3% EPF addition positively affects the biosynthesis of phenylpropanoids, which strongly correlate with the antioxidant and anti-inflammatory properties. In conclusion, the proper addition level did not affect the growth performance, and the PFP and EPF could improve the antioxidation state, anti-inflammatory activity, and intestinal functions of Sanhuang broilers to some extent.

Antimicrobial overproduction sustains intestinal inflammation by inhibiting Enterococcus colonization

Loss of antimicrobial proteins such as REG3 family members compromises the integrity of the intestinal barrier. Here, we demonstrate that overproduction of REG3 proteins can also be detrimental by reducing a protective species in the microbiota. Patients with inflammatory bowel disease (IBD) experiencing flares displayed heightened levels of secreted REG3 proteins that mediated depletion of Enterococcus faecium ( Efm ) from the gut microbiota. Efm inoculation of mice ameliorated intestinal inflammation through activation of the innate immune receptor NOD2, which was associated with the bacterial DL-endopeptidase SagA. Microbiota sensing by NOD2 in myeloid cells mediated IL-1β secretion and increased the proportion of IL-22-producing CD4 + T helper cells and innate lymphoid cells. Finally, Efm was unable to protect mice carrying a NOD2 gene variant commonly found in IBD patients. Our findings demonstrate that inflammation self-perpetuates by causing aberrant antimicrobial activity that disrupts symbiotic relationships with gut microbes.

Immunological consequences of microbiome-based therapeutics

The complex network of microscopic organisms living on and within humans, collectively referred to as the microbiome, produce wide array of biologically active molecules that shape our health. Disruption of the microbiome is associated with susceptibility to a range of diseases such as cancer, diabetes, allergy, obesity, and infection. A new series of next-generation microbiome-based therapies are being developed to treat these diseases by transplanting bacteria or bacterial-derived byproducts into a diseased individual to reset the recipient's microbiome and restore health. Microbiome transplantation therapy is still in its early stages of being a routine treatment option and, with a few notable exceptions, has had limited success in clinical trials. In this review, we highlight the successes and challenges of implementing these therapies to treat disease with a focus on interactions between the immune system and microbiome-based therapeutics. The immune activation status of the microbiome transplant recipient prior to transplantation has an important role in supporting bacterial engraftment. Following engraftment, microbiome transplant derived signals can modulate immune function to ameliorate disease. As novel microbiome-based therapeutics are developed, consideration of how the transplants will interact with the immune system will be a key factor in determining whether the microbiome-based transplant elicits its intended therapeutic effect.

Relevance of biomarkers indicating gut damage and microbial translocation in people living with HIV

The intestinal barrier has the daunting task of allowing nutrient absorption while limiting the entry of microbial products into the systemic circulation. HIV infection disrupts the intestinal barrier and increases intestinal permeability, leading to microbial product translocation. Convergent evidence has shown that gut damage and an enhanced level of microbial translocation contribute to the enhanced immune activation, the risk of non-AIDS comorbidity, and mortality in people living with HIV (PLWH). Gut biopsy procedures are invasive, and are not appropriate or feasible in large populations, even though they are the gold standard for intestinal barrier investigation. Thus, validated biomarkers that measure the degree of intestinal barrier damage and microbial translocation are needed in PLWH. Hematological biomarkers represent an objective indication of specific medical conditions and/or their severity, and should be able to be measured accurately and reproducibly via easily available and standardized blood tests. Several plasma biomarkers of intestinal damage, i.e., intestinal fatty acid-binding protein (I-FABP), zonulin, and regenerating islet-derived protein-3α (REG3α), and biomarkers of microbial translocation, such as lipopolysaccharide (LPS) and (1,3)-β-D-Glucan (BDG) have been used as markers of risk for developing non-AIDS comorbidities in cross sectional analyses and clinical trials, including those aiming at repair of gut damage. In this review, we critically discuss the value of different biomarkers for the estimation of gut permeability levels, paving the way towards developing validated diagnostic and therapeutic strategies to repair gut epithelial damage and to improve overall disease outcomes in PLWH.

The efficacy of probiotics on the prevention of pouchitis for patients after ileal pouch-anal anastomosis: A meta-analysis

BACKGROUND

To date, a few studies indicated that probiotics are beneficial to pouchitis, but no meta-analyses summarized the outcomes of probiotics in pouchitis in detail.

OBJECTIVE

This meta-analysis discusses probiotics in the prevention of pouchitis for patients after ileal pouch-anal anastomosis (IPAA) and the relationship between probiotics preventive effect and the duration of therapy and history.

METHODS

PubMed, EMBASE and Cochrane Library databases were searched from inception until February 2022. Risk ratio (RR), mean difference (MD) and their 95% confidence interval (CI) were analyzed by Review Manager 5.3. The subgroup analysis was also performed to explore the agent for influencing outcomes.

RESULTS

A total of 8 studies were included in this meta-analysis. The incidence of pouchitis in probiotics was significantly lower than that in the control (RR = 0.19, 95%CI [0.12, 0.32], P⁢ï⁢¼⁢ 0.00001), and the PDAI (pouchitis disease activity index) in probiotics was also significantly lower (MD =-5.65, 95%CI [-9.48, -1.83]). After the subgroup analysis, we found that probiotics work better in the short-term (RR = 0.12, 95%CI [0.04, 0.40], P= 0.0004), but may not achieve the desired effect in the long-term (RR = 1.20, 95%CI [0.40, 3.60], P= 0.75).

CONCLUSIONS

Probiotics are beneficial in the prevention of pouchitis after IPAA, especially in the short-term.

Gut-Derived Metabolites from Dietary Tryptophan Supplementation Quench Intestinal Inflammation through the AMPK-SIRT1-Autophagy Pathway

Tryptophan has drawn wide attention due to its involvement in improving intestinal immune defense directly and indirectly by regulating metabolic pathways. The study aims to elucidate the potential modulating roles of tryptophan to protect against intestinal inflammation and elucidate the underlying molecular mechanisms. The protective effects of tryptophan against intestinal inflammation are examined in the lipopolysaccharide (LPS)-induced inflammatory model. We first found that tryptophan markedly (p < 0.01) inhibited proinflammatory cytokines production and nuclear factor κB (NF-κB) pathway activation upon LPS challenge. Next, we demonstrated that tryptophan (p < 0.05) attenuated LPS-caused intestinal mucosal barrier damage by increasing the number of goblet cells, mucins, and antimicrobial peptides (AMPs) in the ileum of mice. In addition, tryptophan (p < 0.05) inhibited LPS-induced autophagic flux through the AMP-activated protein kinase (AMPK)-sirtuin 1 (SIRT1) pathway in the intestinal systems to maintain autophagy homeostasis. Meanwhile, tryptophan also reshaped the gut microbiota composition in LPS-challenge mice by increasing the abundance of short-chain fatty acid (SCFA)-producing bacteria such as Acetivibrio (0.053 ± 0.017 to 0.21 ± 0.0041%). Notably, dietary tryptophan resulted in the activation of metabolic pathways during the inflammatory response. Furthermore, exogenous treatment of tryptophan metabolites kynurenine (Kyn) and 5-HT in porcine intestinal epithelial cells (IPEC-J2 cells) reproduced similar protective effects as tryptophan to attenuate LPS-induced intestinal inflammation through regulating the AMPK-SIRT1-autophagy. Taken together, the present study indicates that tryptophan exhibits intestinal protective and immunoregulatory effects resulting from the activation of metabolic pathways, maintenance of gut mucosal barrier integrity, microbiota composition, and AMPK-SIRT1-autophagy level.

The gut peptide Reg3g links the small intestine microbiome to the regulation of energy balance, glucose levels, and gut function

Changing composition of the gut microbiome is an important component of the gut adaptation to various environments, which have been implicated in various metabolic diseases including obesity and type 2 diabetes, but the mechanisms by which the microbiota influence host physiology remain contentious. Here we find that both diets high in the fermentable fiber inulin and vertical sleeve gastrectomy increase intestinal expression and circulating levels of the anti-microbial peptide Reg3g. Moreover, a number of beneficial effects of these manipulations on gut function, energy balance, and glucose regulation are absent in Reg3g knockout mice. Peripheral administration of various preparations of Reg3g improves glucose tolerance, and this effect is dependent on the putative receptor Extl3 in the pancreas. These data suggest Reg3g acts both within the lumen and as a gut hormone to link the intestinal microbiome to various aspects of host physiology that may be leveraged for novel treatment strategies.

Effects of Donepezil Treatment on Brain Metabolites, Gut Microbiota, and Gut Metabolites in an Amyloid Beta-Induced Cognitive Impairment Mouse Pilot Model

Accumulated clinical and biomedical evidence indicates that the gut microbiota and their metabolites affect brain function and behavior in various central nervous system disorders. This study was performed to investigate the changes in brain metabolites and composition of the fecal microbial community following injection of amyloid β (Aβ) and donepezil treatment of Aβ-injected mice using metataxonomics and metabolomics. Aβ treatment caused cognitive dysfunction, while donepezil resulted in the successful recovery of memory impairment. The Aβ + donepezil group showed a significantly higher relative abundance of Verrucomicrobia than the Aβ group. The relative abundance of 12 taxa, including Blautia and Akkermansia, differed significantly between the groups. The Aβ + donepezil group had higher levels of oxalate, glycerol, xylose, and palmitoleate in feces and oxalate, pyroglutamic acid, hypoxanthine, and inosine in brain tissues than the Aβ group. The levels of pyroglutamic acid, glutamic acid, and phenylalanine showed similar changes in vivo and in vitro using HT-22 cells. The major metabolic pathways in the brain tissues and gut microbiota affected by Aβ or donepezil treatment of Aβ-injected mice were related to amino acid pathways and sugar metabolism, respectively. These findings suggest that alterations in the gut microbiota might influence the induction and amelioration of Aβ-induced cognitive dysfunction via the gut–brain axis. This study could provide basic data on the effects of Aβ and donepezil on gut microbiota and metabolites in an Aβ-induced cognitive impairment mouse model.

Estrogen receptor β deficiency impairs gut microbiota: a possible mechanism of IBD-induced anxiety-like behavior

BACKGROUND

Although the lack of estrogen receptor β (ERβ) is a risk factor for the development of inflammatory bowel disease (IBD) and psychiatric disorders, the underlying cellular and molecular mechanisms are not fully understood. Herein, we revealed the role of gut microbiota in the development of IBD and related anxiety-like behavior in ERβ-deficient mice.

RESULTS

In response to dextran sodium sulfate (DSS) insult, the ERβ knockout mice displayed significant shift in α and β diversity in the fecal microbiota composition and demonstrated worsening of colitis and anxiety-like behaviors. In addition, DSS-induced colitis also induced hypothalamic-pituitary-adrenal (HPA) axis hyperactivity in ERβ-deficient mice, which was associated with colitis and anxiety-like behaviors. In addition, RNA sequencing data suggested that ErbB4 might be the target of ERβ that is involved in regulating the HPA axis hyperactivity caused by DSS insult. Gut microbiota remodeling by co-housing showed that both the colitis and anxiety-like behaviors were aggravated in co-housed wild-type mice compared to single-housed wild-type mice. These findings suggest that gut microbiota play a critical role in mediating colitis disease activity and anxiety-like behaviors via aberrant neural processing within the gut-brain axis.

CONCLUSIONS

ERβ has the potential to inhibit colitis development and anxiety-like behaviors via remodeling of the gut microbiota, which suggests that ERβ is a promising therapeutic target for the treatment of IBD and related anxiety-like behaviors. Video Abstract.

Huangshan Maofeng Green Tea Extracts Prevent Obesity-Associated Metabolic Disorders by Maintaining Homeostasis of Gut Microbiota and Hepatic Lipid Classes in Leptin Receptor Knockout Rats

Huangshan Maofeng green tea (HMGT) is one of the most well-known green teas consumed for a thousand years in China. Research has demonstrated that consumption of green tea effectively improves metabolic disorders. However, the underlying mechanisms of obesity prevention are still not well understood. This study investigated the preventive effect and mechanism of long-term intervention of Huangshan Maofeng green tea water extract (HTE) on obesity-associated metabolic disorders in leptin receptor knockout (Lepr^−/−) rats by using gut microbiota and hepatic lipidomics data. The Lepr^−/− rats were administered with 700 mg/kg HTE for 24 weeks. Our results showed that HTE supplementation remarkably reduced excessive fat accumulation, as well as ameliorated hyperlipidemia and hepatic steatosis in Lepr^−/− rats. In addition, HTE increased gut microbiota diversity and restored the relative abundance of the microbiota responsible for producing short chain fatty acids, including Ruminococcaceae, Faecalibaculum, Veillonellaceae, etc. Hepatic lipidomics analysis found that HTE significantly recovered glycerolipid and glycerophospholipid classes in the liver of Lepr^−/− rats. Furthermore, nineteen lipid species, mainly from phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), and triglycerides (TGs), were significantly restored increases, while nine lipid species from TGs and diglycerides (DGs) were remarkably recovered decreases by HTE in the liver of Lepr^−/− rats. Our results indicated that prevention of obesity complication by HTE may be possible through maintaining homeostasis of gut microbiota and certain hepatic lipid classes.

Neonatal microbiota-epithelial interactions that impact infection

Despite modern therapeutic developments and prophylactic use of antibiotics during birth or in the first few months of life, enteric infections continue to be a major cause of neonatal mortality and morbidity globally. The neonatal period is characterized by initial intestinal colonization with microbiota and concurrent immune system development. It is also a sensitive window during which perturbations to the environment or host can significantly impact colonization by commensal microbes. Extensive research has demonstrated that these early life alterations to the microbiota can lead to enhanced susceptibility to enteric infections and increased systemic dissemination in newborns. Various contributing factors continue to pose challenges in prevention and control of neonatal enteric infections. These include alterations in the gut microbiota composition, impaired immune response, and effects of maternal factors. In addition, there remains limited understanding for how commensal microbes impact host-pathogen interactions in newborns. In this review, we discuss the recent recognition of initial microbiota-epithelial interactions that occur in neonates and can regulate susceptibility to intestinal infection. These studies suggest the development of neonatal prophylactic or therapeutic regimens that include boosting epithelial defense through microbiota-directed interventions.

Research progress on the relationship between intestinal microecology and intestinal bowel disease

Intestinal microecology is the main component of human microecology. Intestinal microecology consists of intestinal microbiota, intestinal epithelial cells, and intestinal mucosal immune system. These components are interdependent and establish a complex interaction network that restricts each other. According to the impact on the human body, there are three categories of symbiotic bacteria, opportunistic pathogens, and pathogenic bacteria. The intestinal microecology participates in digestion and absorption, and material metabolism, and inhibits the growth of pathogenic microorganisms. It also acts as the body's natural immune barrier, regulates the innate immunity of the intestine, controls the mucosal barrier function, and also participates in the intestinal epithelial cells' physiological activities such as hyperplasia or apoptosis. When the steady‐state balance of the intestinal microecology is disturbed, the existing core intestinal microbiota network changes and leads to obesity, diabetes, and many other diseases, especially irritable bowel syndrome, inflammatory bowel disease (IBD), and colorectal malignancy. Intestinal diseases, including tumors, are particularly closely related to intestinal microecology. This article systematically discusses the research progress on the relationship between IBD and intestinal microecology from the pathogenesis, treatment methods of IBD, and the changes in intestinal microbiota.

Regenerating islet-derived protein 3α: A promising therapy for diabetes. Preliminary data in rodents and in humans

The aim of our study was to test the hypothesis that administration of Regenerating islet-derived protein 3α (Reg3α), a protein described as having protective effects against oxidative stress and anti-inflammatory activity, could participate in the control of glucose homeostasis and potentially be a new target of interest in the treatment of type 2 diabetes. To that end the recombinant human Reg3α protein was administered for one month in insulin-resistant mice fed high fat diet. We performed glucose and insulin tolerance tests, assayed circulating chemokines in plasma and measured glucose uptake in insulin sensitive tissues. We evidenced an increase in insulin sensitivity during an oral glucose tolerance test in ALF-5755 treated mice vs controls and decreased the pro-inflammatory cytokine C-X-C Motif Chemokine Ligand 5 (CXCL5). We also demonstrated an increase in glucose uptake in skeletal muscle. Finally, correlation studies using human and mouse muscle biopsies showed negative correlation between intramuscular Reg3α mRNA expression (or its murine isoform Reg3γ) and insulin resistance. Thus, we have established the proof of concept that Reg3α could be a novel molecule of interest in the treatment of T2D by increasing insulin sensitivity via a skeletal muscle effect.

Longitudinal 16S rRNA Sequencing Reveals Relationships among Alterations of Gut Microbiota and Nonalcoholic Fatty Liver Disease Progression in Mice

Nonalcoholic fatty liver disease (NAFLD) is a prevalent and progressive disease spectrum ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), yet there is no effective treatment and efficient noninvasive diagnostic method for NASH. The present study investigated the longitudinal alternations of gut microbiota in the Western diet (WD) induced murine NAFLD model using 16S rRNA sequencing. Evident steatosis and inflammation were detected in the liver at the 8th and 12th week, while prompted hepatic oxidative injury and fibrosis were found at the 16th week. In this progressive process, impaired bile acid (BA) metabolism plays a vital part. Long-term WD intervention alters microbial richness and composition in the intestine, shaping characteristic microbial feature correspondence to each NAFLD stage. Descending abundances of Clostridia and Ruminococcaceae were found in NAFLD progression, while inflammation-related microbes [Eubacterium]_fissicatena_group, Romboutsia, and Erysipelatoclostridium were verified to identify borderline NASH at 8th and 12th week, and BA-associated taxa Dubosiella, Bosea, Helicobacter, and Alistipes were recognized as special symbols reflecting the state of oxidative damage and fibrosis in NASH at 16th week. Further, feces and colon abundances of Akkermansia were verified to be depleted in the process of borderline NASH progressed to NASH, and exhibited substantial correlations with NAFLD indexes ALT, AST, TC, and TBA. These characteristic taxa were effective to identify NAFLD and NASH, and microbiota-derived predictive models for NAFLD and NASH exhibited great potential (AUC 0.983 and 0.784). These findings demonstrate that a core set of gut microbiome especially BA-related taxa may be adopted as a noninvasive diagnostic tool for NAFLD and NASH.

IMPORTANCE This study concentrates on longitudinal alternations of gut microbiota in NAFLD progression and discovers the interrelationships between them. These findings may uncover the role of gut microbiota in NAFLD progression and identify novel noninvasive diagnostic tools for NAFLD based on microbial biomarkers.

Oral antimicrobial peptide-EGCG nanomedicines for synergistic treatment of ulcerative colitis

The pathogenesis of ulcerative colitis (UC) is associated with severe inflammation, damaged colonic barriers, increased oxidative stress, and intestinal dysbiosis. The majority of current medications strive to alleviate inflammation but fail to target additional disease pathologies. Addressing multiple symptoms using a single 'magic bullet' remains a challenge. To overcome this, a smart epigallocatechin-3-gallate (EGCG)-loaded silk fibroin-based nanoparticle (NP) with the surface functionalization of antimicrobial peptides (Cathelicidin-BF, CBF) was constructed, which were internalized by Colon-26 cells and RAW 264.7 macrophages with high efficiencies. These CBF-EGCG-NPs efficiently restored colonic epithelial barriers by relieving oxidative stress and promoting epithelium migration. They also alleviated immune responses through the downregulation of pro-inflammatory factors, upregulation of anti-inflammatory factors, M2 macrophage polarization, and lipopolysaccharide (LPS) elimination. Interestingly, oral administration of hydrogel (chitosan/alginate)-embedding CBF-EGCG-NPs could not only retard progression and treat UC, but also modulate intestinal microbiota by increasing their overall diversity and richness and augmenting the abundance of beneficial bacteria (e.g., Firmicutes and Lactobacillaceae). Our work provides a "many birds with one stone" strategy for addressing UC symptoms using a single NP-based oral platform that targets immune microenvironment modulation, LPS clearance, and microbial remodeling.

Methamphetamine induces intestinal injury by altering gut microbiota and promoting inflammation in mice

Methamphetamine (METH) is a psychostimulant abused worldwide. Its abuse induces intestinal toxicity. Moreover, the gut microbiota is altered by drugs, which induces intestinal injury. Whether gut microbiota mediates METH-induced intestinal toxicity remains to be validated. In the present study, wild-type and TLR4^-/- mice were treated with METH. Gut microbiota was determined using 16S rRNA gene sequencing. Transcriptomics of the intestinal mucosa was performed by RNA-Sequencing. Blood levels of pro-inflammatory cytokines and lipopolysaccharide (LPS), the intestinal barrier, and inflammation were also assessed. METH treatment weakened the intestinal barrier and increased pro-inflammatory cytokines and LPS levels in the blood. Moreover, METH treatment significantly decreased the diversity of probiotics but increased the abundance of pathogenic gut microbiota, contributing to the over-production of LPS and disruption of intestinal barrier. Inflammatory pathways were enriched in the intestinal mucosa of METH-treated mice by KEGG analysis. Consistently, activation of the TLR4 pathway was determined in METH-treated mice, which confirmed intestinal inflammation. However, pretreatment with antibiotics or Tlr4 silencing significantly alleviated METH-induced gut microbiota dysbiosis, LPS over-production, intestinal inflammation, and disruption of the intestinal barrier. These findings suggested that the gut microbiota and LPS-mediated inflammation took an important role in METH-induced intestinal injury. Taken together, these findings suggest that METH-induced intestinal injury is mediated by gut microbiota dysbiosis and LPS-associated inflammation.

Role of metabolites derived from gut microbiota in inflammatory bowel disease

Over the past two decades, it is improved gut microbiota plays an important role in the health and disease pathogenesis. Metabolites, small molecules produced as intermediate or end products of microbial metabolism, is considered as one of the major interaction way for gut microbiota with the host. Bacterial metabolisms of dietary substrates, modification of host molecules or bacteria are the major source of metabolites. Signals from microbial metabolites affect immune maturation and homeostasis, host energy metabolism as well as mucosal integrity maintenance. Based on many researches, the composition and function of the microbiota can be changed, which is also seen in the metabolite profiles of patients with inflammatory bowel disease (IBD). Additionally, some specific classes of metabolites also can trigger IBD. In this paper, definition of the key classes of microbial-derived metabolites which are changed in IBD, description of the pathophysiological basis of association and identification of the precision therapeutic modulation in the future are the major contents.

Role of metabolites derived from gut microbiota in inflammatory bowel disease

Over the past two decades, it is improved gut microbiota plays an important role in the health and disease pathogenesis. Metabolites, small molecules produced as intermediate or end products of microbial metabolism, is considered as one of the major interaction way for gut microbiota with the host. Bacterial metabolisms of dietary substrates, modification of host molecules or bacteria are the major source of metabolites. Signals from microbial metabolites affect immune maturation and homeostasis, host energy metabolism as well as mucosal integrity maintenance. Based on many researches, the composition and function of the microbiota can be changed, which is also seen in the metabolite profiles of patients with inflammatory bowel disease (IBD). Additionally, some specific classes of metabolites also can trigger IBD. In this paper, definition of the key classes of microbial-derived metabolites which are changed in IBD, description of the pathophysiological basis of association and identification of the precision therapeutic modulation in the future are the major contents.

Postnatal intestinal mucosa and gut microbial composition develop hand in hand: A mouse study

BACKGROUND

During the early postnatal life, gut microbiota development experiences dynamic changes in their structural and functional composition. The postnatal period is the critical window to develop a host defense mechanism. The maturation of intestinal mucosal barrier integrity is one of the essential defense mechanisms to prevent the entry of pathogens. However, the co-development of intestinal microbial colonization, formation of barrier integrity, and intestinal epithelial cell layer is not entirely understood.

METHODS

We studied the gut microbial composition and diversity using 16S rRNA marker gene-based sequencing in mice to understand postnatal age-dependent association kinetics between gut microbial and intestinal development. Next, we assessed the intestinal development by in vivo gut permeability assay, mRNA gene expression of different tight junction proteins and intestinal epithelial cell markers, goblet cells population, villus length, and cecal IgA quantification.

RESULTS

Our results showed a significant shift in gut microbial structural and functional composition from postnatal day 14 onwards with early life Proteobacteria abundance. Relative abundance of Verrucomicrobia was maximum at postnatal day 14 and showed a gradual decrease over time. We also observed an age-dependent biphasic pattern in barrier integrity improvement and differentiation of intestinal epithelial cells (IECs). A significant improvement in barrier integrity between days 1 and 7 showed the host factor contribution, while that beyond day 14 revealed an association with changes in microbiota composition. Our temporal correlation analysis associated Bacteroidetes phylum with the mucosal barrier formation during postnatal development.

CONCLUSIONS

The present study revealed the importance and interplay of host factors and the microbiome in gut development and intestinal mucosal homeostasis.

Effects of different courses of moxibustion treatment on intestinal flora and inflammation of a rat model of knee osteoarthritis

OBJECTIVE

This study was done to determine the effects of different courses of moxibustion on a rat knee osteoarthritis (KOA) model, and explore the dose-effect relationship of moxibustion on KOA from the perspectives of intestinal flora and inflammatory factors.

METHODS

Wistar rats were randomly divided into five groups: normal, model, moxibustion for 2 weeks, moxibustion for 4 weeks and moxibustion for 6 weeks groups (n = 5 each group). A KOA rat model was induced by monosodium iodoacetate, and moxibustion intervention was performed at the acupoints "Dubi" (ST35) and "Zusanli" (ST36), once every other day. Pathologic changes in the cartilage of rat knee joints were assessed after intervention, and fecal samples were subjected to 16S rRNA high-throughput sequencing for microbial diversity analysis.

RESULTS

Damage to the knee articular cartilage was obvious in the model group, which also had increased levels of pro-inflammatory factors, decreased levels of anti-inflammatory factors, and intestinal flora disorders with decreased diversity. The degree of cartilage damage in the 4 and 6 weeks of moxibustion groups was significantly improved compared with the model group. The 4 and 6 weeks of moxibustion groups also demonstrated reduced levels of interleukin-1β and tumor necrosis factor-α and increased levels of interleukin-10 (P < 0.05). Both the abundance and diversity of the intestinal flora were increased, approaching those of the normal group. Abundances of probiotics Eubacterium coprostanoligenes group and Ruminococcaceae UCG-014 increased, while that of the pathogenic bacteria Lachnospiraceae NK4A136 group decreased (P < 0.05). Although the abundance of Lachnospiraceae NK4A136 group decreased in the 2 weeks of moxibustion group compared with the model group (P < 0.05), there was no statistically significant difference in serum inflammatory factors, flora species diversity or degree of pathological damage compared with the model group.

CONCLUSION

Moxibustion treatment led to significant improvements in the intestinal flora and inflammatory factors of rats with KOA. Moxibustion treatment of 4 and 6 weeks led to better outcomes than the 2-week course. Moxibustion for 4 and 6 weeks can regulate intestinal flora dysfunction with increased probiotics and reduced pathogenic bacteria, reduce pro-inflammatory factors and increase anti-inflammatory factors. No significant differences were seen between the effects of moxibustion for 4 weeks and 6 weeks.

Molecular Patterns in Acute Pancreatitis Reflect Generalizable Endotypes of the Host Response to Systemic Injury in Humans

OBJECTIVE

Acute Pancreatitis (AP) is sudden onset pancreas inflammation that causes systemic injury with a wide and markedly heterogeneous range of clinical consequences. Here, we hypothesized that this observed clinical diversity corresponds to diversity in molecular subtypes that can be identified in clinical and multiomics data.

SUMMARY BACKGROUND DATA

Observational cohort study. n = 57 for the discovery cohort (clinical, transcriptomics, proteomics, and metabolomics data) and n = 312 for the validation cohort (clinical and metabolomics data).

METHODS

We integrated coincident transcriptomics, proteomics, and metabolomics data at serial time points between admission to hospital and up to 48 hours after recruitment from a cohort of patients presenting with acute pancreatitis. We systematically evaluated 4 different metrics for patient similarity using unbiased mathematical, biological, and clinical measures of internal and external validity.We next compared the AP molecular endotypes with previous descriptions of endotypes in a critically ill population with acute respiratory distress syndrome (ARDS).

RESULTS

Our results identify 4 distinct and stable AP molecular endotypes. We validated our findings in a second independent cohort of patients with AP.We observed that 2 endotypes in AP recapitulate disease endotypes previously reported in ARDS.

CONCLUSIONS

Our results show that molecular endotypes exist in AP and reflect biological patterns that are also present in ARDS, suggesting that generalizable patterns exist in diverse presentations of critical illness.

Roseburia intestinalis: A Beneficial Gut Organism From the Discoveries in Genus and Species

Roseburia intestinalis is an anaerobic, Gram-positive, slightly curved rod-shaped flagellated bacterium that produces butyrate in the colon. R. intestinalis has been shown to prevent intestinal inflammation and maintain energy homeostasis by producing metabolites. Evidence shows that this bacterium contributes to various diseases, such as inflammatory bowel disease, type 2 diabetes mellitus, antiphospholipid syndrome, and atherosclerosis. This review reveals the potential therapeutic role of R. intestinalis in human diseases. Patients with inflammatory bowel disease exhibit significant changes in R. intestinalis abundance, and they may benefit a lot from modulations targeting R. intestinalis. The data reviewed here demonstrate that R. intestinalis plays its role in regulating barrier homeostasis, immune cells, and cytokine release through its metabolite butyrate, flagellin and other. Recent advancements in the application of primary culture technology, culture omics, single-cell sequencing, and metabonomics technology have improved research on Roseburia and revealed the benefits of this bacterium in human health and disease treatment.

Colonization resistance against multi-drug-resistant bacteria: a narrative review

Colonization resistance by gut microbiota is a fundamental phenomenon in infection prevention and control. Hospitalized patients may be exposed to multi-drug-resistant bacteria when hand hygiene compliance among healthcare workers is not adequate. An additional layer of defence is provided by the healthy gut microbiota, which helps clear the exogenous bacteria and acts as a safety net when hand hygiene procedures are not followed. This narrative review focuses on the role of the gut microbiota in colonization resistance against multi-drug-resistant bacteria, and its implications for infection control. The review discusses the underlying mechanisms of colonization resistance (direct or indirect), the concept of resilience of the gut microbiota, the link between the antimicrobial spectrum and gut dysbiosis, and possible therapeutic strategies. Antimicrobial stewardship is crucial to maximize the effects of colonization resistance. Avoiding unnecessary antimicrobial therapy, shortening the antimicrobial duration as much as possible, and favouring antibiotics with low anti-anaerobe activity may decrease the acquisition and expansion of multi-drug-resistant bacteria. Even after antimicrobial therapy, the resilience of the gut microbiota often occurs spontaneously. Spontaneous resilience explains the existence of a window of opportunity for colonization of multi-drug-resistant bacteria during or just after antimicrobial therapy. Strategies favouring resilience of the gut microbiota, such as high-fibre diets or precision probiotics, should be evaluated.

An engineered probiotic secreting Sj16 ameliorates colitis via Ruminococcaceae/butyrate/retinoic acid axis

Most inflammatory bowel disease (IBD) patients are unable to maintain a lifelong remission. Developing a novel therapeutic strategy is urgently needed. In this study, we adopt a new strategy to attenuate colitis using the Escherichia coli Nissle 1917 probiotic strain to express a schistosome immunoregulatory protein (Sj16) in the gastrointestinal tract. The genetically engineered Nissle 1917 (EcN-Sj16) highly expressed Sj16 in the gastrointestinal tracts of dextran sulfate sodium-induced colitis mice and significantly attenuated the clinical activity of colitis mice. Mechanistically, EcN-Sj16 increased the intestinal microbiota diversity and selectively promoted the growth of Ruminococcaceae and therefore enhanced the butyrate production. Butyrate induced the expression of retinoic acid, which further attenuated the clinical activity of colitis mice by increasing Treg cells and decreasing Th17. Strikingly, retinoic acid inhibitor inhibited the therapeutic effects of EcN-Sj16 in colitis mice. These findings suggest that EcN-Sj16 represents a novel engineered probiotic that may be used to treat IBD.