Lipopolysaccharide causes an increase in intestinal tight junction permeability in vitro and in vivo by inducing enterocyte membrane expression and localization of TLR-4 and CD14

Oral Lipid-Based Nanomedicine for the Inhibition of the cGAS-STING Pathway in Inflammatory Bowel Disease Treatment

Harnessing the effect of the cyclic GMP-AMP Synthase-STimulator of INterferon Genes (cGAS-STING) signaling pathway has emerged as a promising approach to developing novel strategies for the oral treatment of inflammatory bowel disease (IBD). In this work, we screened different cGAS-STING inhibitors in vitro in murine macrophages. Then, we encapsulated the cGAS-STING inhibitor H-151 within lipid nanocapsules (LNCs), owing to their inherent ability to induce the secretion of glucagon-like peptide 2 (GLP-2), a re-epithelizing peptide, upon oral administration. We demonstrated that our formulation (LNC(H-151)) could induce GLP-2 secretion and selectively target the cGAS-STING pathway and its downstream key markers (including TBK1 and pTBK1) while reducing the expression of pro-inflammatory cytokines associated with the cGAS-STING pathway (TNF-α and CXCL10) in murine macrophages. In an in vivo acute dextran sodium sulfate (DSS)-induced colitis mouse model, the oral administration of LNC(H-151) significantly reduced pro-inflammatory cytokines to levels comparable to the CTRL Healthy group while promoting mucosal healing. The therapeutic potential of this scalable and cost-effective nanomedicine warrants further investigation as an alternative for the oral treatment of IBD.

Glucagon-Like Peptide-1 Is Prognostic of Mortality in Acute Respiratory Failure

OBJECTIVES

The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) have therapeutic effects in diabetes mellitus. Prior clinical studies suggest incretins are prognostic of adverse outcomes in critical illness. We investigated whether incretin levels indicate disease severity and clinical outcomes in patients with acute respiratory failure, a common cause of critical illness.

DESIGN

Retrospective cohort study.

SETTING

ICUs in UPMC Health Systems hospitals within Western Pennsylvania.

PATIENTS

Two hundred ninety-seven critically ill adults with acute respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured GLP-1 and GIP levels in baseline samples collected at the time of study enrollment. We compared incretin levels across subgroups differing by severity of illness and investigated associations between incretins and markers of systemic host responses and intestinal permeability. In our primary analysis, we tested the association of each incretin level with 90-day mortality by logistic regression in unadjusted analyses and in analyses adjusted for age, Sequential Organ Failure Assessment score, and circulating interleukin-6 levels. GLP-1 levels were higher in nonsurvivors and patients with or at-risk for acute respiratory distress syndrome compared to those intubated for airway protection. GLP-1 levels also positively correlated with systemic immune response biomarkers but not with markers of intestinal permeability. GLP-1 levels positively correlated with mortality in unadjusted (odds ratio, 1.99 [1.55-2.56]; p < 0.01) and adjusted (2.02 [1.23-3.31]; p < 0.01) analyses. GIP levels were not associated with mortality or with host response biomarkers.

CONCLUSIONS

GLP-1 but not GIP levels were positively associated with systemic inflammation and mortality in critically ill patients with acute respiratory failure. Increased circulating GLP-1 levels may serve as prognostic biomarkers to identify patients who are likely to have worse outcomes.

Immunomodulatory Properties of Live and Thermally-Inactivated Food-Origin Lactic Acid Bacteria-In Vitro Studies

The study investigates the strain-specific immunomodulatory properties of live and thermally-inactivated (TI) lactic acid bacteria (LAB) derived from traditional Polish fermented foods, focusing on their potential as probiotics and postbiotics. LAB strains, known for their role in food fermentation, were assessed for their ability to influence cytokine production in THP-1 macrophages, maintain intestinal epithelial barrier integrity in Caco-2 monolayers, exhibit antioxidant activity, and produce specific organic acids and sugars. The research demonstrated that live LAB strains significantly upregulated the anti-inflammatory cytokine IL-10, particularly under inflammatory conditions, while TI strains exhibited notable antioxidant and anti-inflammatory properties. TI strains showed a greater ability to protect epithelial barrier function and reduce pro-inflammatory cytokine secretion than live strains, suggesting a promising role for postbiotics. The findings underscore the potential of LAB from fermented foods, demonstrating that postbiotic derivatives can differently influence inflammation compared to live bacteria, highlighting their potential as immune-enhancing agents, capable of modulating immune responses and offering therapeutic benefits against inflammation-related disorders. However, the limitations of in vitro models highlight the need for further in vivo and clinical studies to validate these effects and fully uncover the health benefits of these LAB strains for humans.

Simulated Microplastic Release from Cutting Boards and Evaluation of Intestinal Inflammation and Gut Microbiota in Mice

BACKGROUND

Plastic cutting boards are commonly used in food preparation, increasing human exposure to microplastics (MPs). However, the health implications are still not well understood.

OBJECTIVES

The objective of this study was to assess the impacts of long-term exposure to MPs released from cutting boards on intestinal inflammation and gut microbiota.

METHODS

MPs were incorporated into mouse diets by cutting the food on polypropylene (PP), polyethylene (PE), and willow wooden (WB) cutting boards, and the diets were fed to mice over periods of 4 and 12 wk. Serum levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α ), interleukin-10 (IL-10), lipopolysaccharide (LPS, an endotoxin), and carcinoembryonic antigen (CEA), along with ileum and colon levels of interleukin-1β (IL-1 β ), TNF-α , malondialdehyde (MDA), superoxide dismutase (SOD), secretory immunoglobulin A (sIgA), and myosin light chain kinase (MLCK), were measured using mouse enzyme-linked immunosorbent assay (ELISA) kits. The mRNA expression of mucin 2 and intestinal tight junction proteins in mouse ileum and colon tissues was quantified using real-time quantitative reverse transcription polymerase chain reaction. Fecal microbiota, fecal metabolomics, and liver metabolomics were characterized.

RESULTS

PP and PE cutting boards released MPs, with concentrations reaching 1,088 ± 95.0 and 1,211 ± 322 μ g / g in diets, respectively, and displaying mean particle sizes of 10.4 ± 0.96 vs. 27.4 ± 1.45 μ m . Mice fed diets prepared on PP cutting boards for 12 wk exhibited significantly higher serum levels of LPS, CRP, TNF-α , IL-10, and CEA, as well as higher levels of IL-1β , TNF-α , MDA, SOD, and MLCK in the ileum and colon compared with mice fed diets prepared on WB cutting boards. These mice also showed lower relative expression of Occludin and Zonula occludens-1 in the ileum and colon. In contrast, mice exposed to diets prepared on PE cutting boards for 12 wk did not show evident inflammation; however, there was a significant decrease in the relative abundance of Firmicutes and an increase in Desulfobacterota compared with those fed diets prepared on WB cutting boards, and exposure to diets prepared on PE cutting boards over 12 wk also altered mouse fecal and liver metabolites compared with those fed diets prepared on WB cutting boards.

DISCUSSION

The findings suggest that MPs from PP cutting boards impair intestinal barrier function and induce inflammation, whereas those from PE cutting boards affect the gut microbiota, gut metabolism, and liver metabolism in the mouse model. These findings offer crucial insights into the safe use of plastic cutting boards. https://doi.org/10.1289/EHP15472.

Alterations in gut microbial community structure in obstructive sleep apnea /hypopnea syndrome (OSAHS): A systematic review and meta-analysis

OBJECTIVES

This systematic review investigates gut bacterial diversity and composition in patients with Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) and examines how these changes may contribute to cardiovascular complications.

METHODS

A comprehensive search was conducted in PubMed, Web of Science, and Scopus up to March 2025. After removing duplicates, titles and abstracts were screened by two reviewers, and full texts were assessed for inclusion. Data extraction on study characteristics and outcomes was performed. Methodological quality was evaluated using the Joanna Briggs Institute checklist. α-diversity was assessed using richness and diversity indices, while β-diversity examined community structure differences. Meta-analysis was conducted using standardized mean differences (SMD) and confidence intervals (CIs), and heterogeneity was assessed with the Cochrane I2 test.

RESULTS

The review included 18 studies (16 adults, 2 pediatrics) examining the gut microbiome in OSAHS. Meta-analysis revealed significant reductions in α-diversity indices (Shannon, Chao1, observed species, ACE) in OSAHS patients, while Simpson's index showed no difference. β-diversity analyses showed distinct gut microbiome differences in OSA. Key differential bacteria included Bacteroides, Proteobacteria, Faecalibacterium, Ruminococcaceae, Megamonas, Oscillibacter, Dialister, Roseburia, and Lachnospira. Study quality was medium to high.

CONCLUSION

OSAHS is associated with significant gut microbiome alterations, including a reduction in beneficial bacteria and an increase in LPS-producing bacteria, leading to intestinal barrier dysfunction. These changes may contribute to systemic inflammation and elevate the risk of cardiovascular diseases.

Sublethal systemic LPS in mice enables gut-luminal pathogens to bloom through oxygen species-mediated microbiota inhibition

Endotoxin-driven systemic immune activation is a common hallmark across various clinical conditions. During acute critical illness, elevated plasma lipopolysaccharide triggers non-specific systemic immune activation. In addition, a compositional shift in the gut microbiota, including an increase in gut-luminal opportunistic pathogens, is observed. Whether a causal link exists between acute endotoxemia and abundance of gut-luminal opportunistic pathogens is incompletely understood. Here, we model acute, pathophysiological lipopolysaccharide concentrations in mice and show that systemic exposure promotes a 100-10'000-fold expansion of Klebsiella pneumoniae, Escherichia coli, Enterococcus faecium and Salmonella Typhimurium in the gut within one day, without overt enteropathy. Mechanistically, this is driven by a Toll-like receptor 4-dependent increase in gut-luminal oxygen species levels, which transiently halts microbiota fermentation and fuels growth of gut-luminal facultative anaerobic pathogens through oxidative respiration. Thus, systemic immune activation transiently perturbs microbiota homeostasis and favours opportunistic pathogens, potentially increasing the risk of infection in critically ill patients.

In vitro liver models for toxicological research

Drug-induced liver injury (DILI) presents a major challenge not only in new drug development but also in post-marketing withdrawals and the safety of food, cosmetics, and chemicals. Experimental model organisms such as the rodents have been widely used for preclinical toxicological testing. However, the tension exists associated with the ethical and sustainable use of animals in part because animals do not necessarily inform the human-specific ADME (adsorption, dynamics, metabolism and elimination) profiling. To establish alternative models in humans, in vitro hepatic tissue models have been proposed, ranging from primary hepatocytes, immortal hepatocytes, to the development of new cell resources such as stem cell-derived hepatocytes. Given the evolving number of novel alternative methods, understanding possible combinations of cell sources and culture methods will be crucial to develop the context-of-use assays. This review primarily focuses on 3D liver organoid models for conducting. We will review the relevant cell sources, bioengineering methods, selection of training compounds, and biomarkers towards the rationale design of in vitro toxicology testing.

Chlorogenic acid mitigates avian pathogenic Escherichia coli-induced intestinal barrier damage in broiler chickens via anti-inflammatory and antioxidant effects: CHLOROGENIC ACID AND BROILER CHICKENS

This study was conducted to investigate the protective effects of chlorogenic acid (CGA) on intestinal health in broilers challenged with avian pathogenic Escherichia coli (APEC). One hundred and eighty one-day-old male broiler chicks were divided into three groups with six replicates of ten chicks each for a 21-day trial. The birds in the control and APEC groups were fed a basal diet, while birds in the CGA-treated group received a basal diet supplemented with 1000 mg/kg of CGA. At 14 days, birds in the APEC and CGA groups were administered with an APEC suspension Compared with the APEC group, CGA incorporation decreased mortality and cecal Escherichia coli colonies in bacterially challenged broilers (P < 0.05). Additionally, CGA reduced the relative weight of the heart, liver, kidney, gizzard, proventriculus, and intestine, as well as serum triglyceride level and alanine aminotransferase activity in APEC-challenged broilers (P < 0.05). Supplementing CGA reduced the concentrations of interferon-γ, tumor necrosis factor-α, interleukin-1β, and/or interleukin-6 in serum, duodenum, jejunum, and/or ileum in APEC-challenged broilers presumably through the inactivation of the toll-like receptor 4/myeloid differentiation factor 88 pathway (P < 0.05). CGA administration reduced serum diamine oxidase activity and d-lactate and endotoxin concentrations, but increased the ratio between villus height and crypt depth in duodenum and jejunum of APEC-infected chickens, accompanied by the restored intestinal expression of tight junction proteins (claudin-1, claudin-2, occludin, and zonula occludens-1) and genes involved in apoptosis (B cell lymphoma-2 associated X protein, B cell lymphoma-2, and cysteine-requiring aspartate protease 9) (P < 0.05). Additionally, CGA increased superoxide dismutase, glutathione peroxidase, and catalase activities, and glutathione levels in serum and intestinal mucosa, but inhibited the accumulation of intestinal malondialdehyde in APEC-challenged broilers possibly via activating the nuclear factor-erythroid 2-related factor-2/heme oxygenase-1 pathway (P < 0.05). The results suggested that CGA alleviated APEC-induced intestinal damage in broilers by inhibiting inflammation and oxidative stress. However, its potential application in practical poultry production is contingent upon both its efficacy and cost-effectiveness.

Association of Low-Calorie Sweeteners with Selected Circulating Biomarkers of Intestinal Permeability in the Cancer Prevention Study-3 Diet Assessment Substudy

BACKGROUND

Low-calorie sweeteners (LCSs) are popular sugar substitutes and have been shown to alter the gut microbiota, which raises concerns about potential impacts on intestinal permeability.

OBJECTIVES

This study aimed to examine cross-sectional associations between LCS consumption and circulating biomarkers of intestinal permeability.

METHODS

We analyzed data from 572 United States adults participating in the Cancer Prevention Study-3 Diet Assessment Substudy who provided ≤2 fasting blood samples, collected 6 mo apart, to measure biomarkers of intestinal permeability including antibodies to flagellin (anti-flagellin), lipopolysaccharide (anti-LPS), and total antibodies; and ≤6 24-h dietary recalls, collected over the course of 12 mo, to estimate average intake of LCS including aspartame, sucralose, acesulfame-potassium, and saccharin. Multivariable linear regression, adjusted for sociodemographic characteristics, lifestyle factors, and medical history, was used to examine associations between LCS consumption and levels of intestinal permeability biomarkers by comparing mean differences in biomarkers among lower (>0 to ≤50th percentile) (n = 158) and higher (>50th percentile) LCS consumers (n = 157) than nonconsumers. A linear trend across nonconsumers and the 2 consumption categories was evaluated using a continuous variable based on the median LCS intake (median = 0, 11.3, and 124.2 mg/d for non-, lower, and higher consumers, respectively).

RESULTS

Among the 572 study participants, the mean age was 52.5 y, 63.3% were female, 60.7% were on-Hispanic White, and 55.1% reported consuming LCS-containing products. Greater LCS consumption was not associated with anti-flagellin, anti-LPS, or total antibodies. Additionally, no associations between specific types of LCS and intestinal permeability biomarkers were observed.

CONCLUSIONS

The results of our study did not demonstrate an association between LCS consumption and intestinal permeability biomarkers. Further research with larger sample sizes and randomized controlled trials is needed to confirm our findings.

Maternal protein restriction impairs intestinal morphophysiology and antioxidant system in young male offspring rats

The developmental origins of health and disease (DOHaD) concept suggests that adverse conditions during gestation can influence the development and function of multiple organs, including the gastrointestinal tract. Maternal protein restriction (MPR) exposure has been associated with negative effects on reproduction, the endocrine system, and liver metabolic health. However, limited research has explored the impact of MPR on the offspring's intestinal morphophysiology. This study investigated the effects of gestational and lactational MPR on the duodenum and colon of young male offspring rats at postnatal (PND)21. We hypothesize that MPR affects intestinal morphophysiology and development early in life. Our findings revealed tachygastria in offspring exposed to MPR. The ultrastructural analysis uncovered a reduction in goblet cell numbers and changes in collagen deposition in the duodenum and colon. We also identified imbalances in inflammatory markers (IL-6 and TGF-β1) and antioxidant enzymes (CAT and SOD). These results demonstrate that MPR significantly affects gastrointestinal morphophysiology early in life by disrupting gastric motility and altering duodenal and colonic histoarchitecture, antioxidant defense, and inflammatory pathways. Such alterations may predispose the descendants to long-term gastrointestinal disorders, underscoring the importance of further research on the developmental origins of intestinal health and disease.

Lipopolysaccharide, arbiter of the gut-liver axis, modulates hepatic cell pathophysiology in alcoholism

Over the last four decades, clinical research and experimental studies have established that lipopolysaccharide (LPS)-a component of the outer membrane of gram-negative bacteria-is a potent hepatotoxic molecule in humans and animals. Alcohol abuse is commonly associated with LPS endotoxemia. This review highlights LPS molecular structures and modes of release from bacteria, plasma LPS concentrations, induction of microbiota dysbiosis, disruption of gut epithelial barrier, and translocation of LPS into the portal circulation impacting the pathophysiology of hepatic cells via the gut-liver axis. We describe and illustrate the portal vein circulation and its distributaries draining the gastrointestinal tract. We also elaborate on the gut-liver axis coupled with enterohepatic circulation that represents a bidirectional communication between the gut and liver. The review also updates the data on how circulating LPS is cleared in a coordinated effort between Kupffer cells, hepatocytes, and liver sinusoidal endothelial cells. Significantly, the article reviews and updates the modes/mechanisms of action by which LPS mediates the diverse pathophysiology of Kupffer cells, hepatocytes, sinusoidal endothelial cells, and hepatic stellate cells primarily in association with alcohol consumption. Specifically, we review the intricate linkages between ethanol, microbiota dysbiosis, LPS production, gut-liver axis, and pathophysiology of various hepatic cells. The maintenance of the gut barrier structural and functional integrity and microbiome homeostasis is essential in mitigating alcoholic liver disease and improving liver health.

Escherichia coli HPI-induced duodenitis through ubiquitin regulation of the TLR4/NF-κB pathway

BACKGROUND

The Highly Pathogenic Island (HPI) found in Yersinia pestis can be horizontally transferred to E. coli, enhancing its virulence and pathogenicity. Ubiquitin (Ub) acts as an activator of the NF-κB pathway and plays a critical role in the inflammatory response. However, the precise mechanism by which Ub and the regulated TLR4/NF-κB pathway contribute to HPI-induced intestinal inflammation in E. coli remains unclear.

RESULTS

In this study, we established Ub overexpression models of small intestinal epithelial cells (in vitro) and BALB/c mice (in vivo) and infected these models with HPI-rich E. coli. We investigated the role of the Ub-regulated TLR4/NF-κB pathway in E. coli HPI-induced intestinal inflammation through qPCR, ELISA, immunofluorescence, immunohistochemistry, and H&E staining. Our findings confirmed that E. coli HPI promoted the expression of Ub, TLR4, and NF-κB in IPEC-J2 cells and induced the translocation of NF-κB p65 protein to the nucleus. Further investigations revealed that Ub overexpression enhanced epithelial cell damage induced by E. coli HPI. This was accompanied by up-regulation of mRNA levels of TLR4, MyD88, NF-κB, IL-1β, and TNF-α, as well as increased release of the inflammatory factors IL-1β and TNF-α. In a mouse model with Ub overexpression infected with E. coli HPI, we observed that Ub overexpression promoted E. coli HPI-induced intestinal inflammation. Mechanistically, E. coli HPI induced intestinal epithelial cell damage by inducing Ub overexpression and modulating the TLR4/NF-κB pathway.

CONCLUSIONS

In conclusion, this study sheds light on the significant role of the Ub-regulated TLR4/NF-κB pathway in E. coli HPI-induced duodenitis, offering novel insights into the pathogenesis of E. coli infections.

Neurotensin via Type I Receptor Modulates the Endotoxemia Induced Oxido-Inflammatory Stress on the Sympathetic Adrenomedullary System of Mice Regulating NF-κβ/Nor-Epinephrine Pathway

The present study investigated the role of the neurotensin/NTS in the modulation of the lipopolysaccharide/LPS induced dysfunction of the sympatho-adrenal-medullary system/SAM using both the NTS receptor 1/NTSR1 agonist PD149163/PD and antagonist SR48692 /SR. Forty eight mice were maintained in eight groups; Group I/control, Groups II, III, IV, and VII received LPS for 5 days further Group III/IV/VII received PD low dose/PDL, PD high dose /PDH and SR for 28 days respectively. Group V/VI received similar only PDL and PDH dose respectively whereas Group VIII was exposed to only SR for 28 days. Adrenal tissues histopathology examined through hematoxylin-eosin staining. The plasma levels of pro-inflammatory mediators (NF-kβ, TNF-α, IL-6), IL-10, corticosterone/CORT, nor-epinephrine/NE and NTS were assessed through ELISA. Biochemical detection was adopted to check the level of oxidative stress, assessed by measuring the thiobarbituric acid reactive substance/TBARS, superoxide dismutase/SOD and catalase/CAT in adrenal tissue to determine the therapeutic effect of NTS receptor 1 analogs. Compared with LPS group, PD ameliorated the adrenal medulla histopathology by significantly decreasing pro-inflammatory mediators, CORT and NE as well as enhancing IL-10, normalizing NTS level via down-regulating NF-κβ level. PD inhibited the oxidative stress in SAM system of adrenal by reducing TBARS, while enhancing SOD and CAT activity via regulating the CORT and NE levels. Conversely, SR administration could not normalize the deleterious effect caused by the LPS due to up-regulation of NF-κβ level. Therefore, PD ameliorates the inflammation and oxidative stress of SAM system by inhibiting NF-kβ/NE signaling pathway. Thus, PD could be used as a biological tool in SAM dysfunction for therapeutic evaluation of chronic inflammatory diseases.

Dietary Influences on Gut Microbiota and Their Role in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major contributor to liver-related morbidity, cardiovascular disease, and metabolic complications. Lifestyle interventions, including diet and exercise, are first line in treating MASLD. Dietary approaches such as the low-glycemic-index Mediterranean diet, the ketogenic diet, intermittent fasting, and high fiber diets have demonstrated potential in addressing the metabolic dysfunction underlying this condition. The development and progression of MASLD are closely associated with taxonomic shifts in gut microbial communities, a relationship well-documented in the literature. Given the importance of diet as a primary treatment for MASLD, it is important to understand how gut microbiota and their metabolic byproducts mediate favorable outcomes induced by healthy dietary patterns. Conversely, microbiota changes conferred by unhealthy dietary patterns such as the Western diet may induce dysbiosis and influence steatotic liver disease through promoting hepatic inflammation, up-regulating lipogenesis, dysregulating bile acid metabolism, increasing insulin resistance, and causing oxidative damage in hepatocytes. Although emerging evidence has identified links between diet, microbiota, and development of MASLD, significant gaps remain in understanding specific microbial roles, metabolite pathways, host interactions, and causal relationships. Therefore, this review aims to provide mechanistic insights into the role of microbiota-mediated processes through the analysis of both healthy and unhealthy dietary patterns and their contribution to MASLD pathophysiology. By better elucidating the interplay between dietary nutrients, microbiota-mediated processes, and the onset and progression of steatotic liver disease, this work aims to identify new opportunities for targeted dietary interventions to treat MASLD efficiently.

Brd4 modulates metabolic endotoxemia-induced inflammation by regulating colonic macrophage infiltration in high-fat diet-fed mice

High-fat diet (HFD) induces low-grade chronic inflammation, contributing to obesity and insulin resistance. However, the precise mechanisms triggering obesity-associated metabolic inflammation remain elusive. In this study, we identified epigenetic factor Brd4 as a key player in this process by regulating the expression of Ccr2/Ccr5 in colonic macrophage. Upon 4-week HFD, myeloid-lineage-specific Brd4 deletion (Brd4-CKO) mice showed reduced colonic inflammation and macrophage infiltration with decreased expression of Ccr2 and Ccr5. Mechanistically, Brd4 was recruited by NF-κB to the enhancer regions of Ccr2 and Ccr5, promoting enhancer RNA expression, which facilitated Ccr2/Ccr5 expression and macrophage migration. Furthermore, decreased infiltration of Ccr2/Ccr5-positive colonic macrophages in Brd4-CKO mice altered gut microbiota composition and reduced intestinal permeability, thereby lowering metabolic endotoxemia. Finally, Brd4-CKO mice subjected to a 4-week LPS infusion exhibited restored susceptibility to HFD-induced obesity and insulin resistance. This study identifies Brd4 as a critical initiator of colonic macrophage-mediated inflammation and metabolic endotoxemia upon HFD, suggesting Brd4 as a potential target for mitigating HFD-induced inflammation, obesity, and its metabolic complications.

Gut microbiota has important roles in the obstructive sleep apnea-induced inflammation and consequent neurocognitive impairment

Obstructive sleep apnea (OSA) is a state of sleep disorder, characterized by repetitive episodes of apnea and chronic intermittent hypoxia. OSA has an extremely high prevalence worldwide and represents a serious challenge to public health, yet its severity is frequently underestimated. It is now well established that neurocognitive dysfunction, manifested as deficits in attention, memory, and executive functions, is a common complication observed in patients with OSA, whereas the specific pathogenesis remains poorly understood, despite the likelihood of involvement of inflammation. Here, we provide an overview of the current state of the art, demonstrating the intimacy of OSA with inflammation and cognitive impairment. Subsequently, we present the recent findings on the investigation of gut microbiota alteration in the OSA conditions, based on both patients-based clinical studies and animal models of OSA. We present an insightful discussion on the role of changes in the abundance of specific gut microbial members, including short-chain fatty acid (SCFA)-producers and/or microbes with pathogenic potential, in the pathogenesis of inflammation and further cognitive dysfunction. The transplantation of fecal microbiota from the mouse model of OSA can elicit inflammation and neurobehavioral disorders in naïve mice, thereby validating the causal relationship to inflammation and cognitive abnormality. This work calls for greater attention on OSA and the associated inflammation, which require timely and effective therapy to protect the brain from irreversible damage. This work also suggests that modification of the gut microbiota using prebiotics, probiotics or fecal microbiota transplantation may represent a potential adjuvant therapy for OSA.

Gut Microbiota and Immune System Dynamics in Parkinson's and Alzheimer's Diseases

The gut microbiota, a diverse collection of microorganisms in the gastrointestinal tract, plays a critical role in regulating metabolic, immune, and cognitive functions. Disruptions in the composition of these microbial communities, termed dysbiosis, have been linked to various neurodegenerative diseases (NDs), such as Parkinson's disease (PD) and Alzheimer's disease (AD). One of the key pathological features of NDs is neuroinflammation, which involves the activation of microglia and peripheral immune cells. The gut microbiota modulates immune responses through the production of metabolites and interactions with immune cells, influencing the inflammatory processes within the central nervous system. This review explores the impact of gut dysbiosis on neuroinflammation, focusing on the roles of microglia, immune cells, and potential therapeutic strategies targeting the gut microbiota to alleviate neuroinflammatory processes in NDs.

Oxidative Stress in Poultry and the Therapeutic Role of Herbal Medicine in Intestinal Health

The intensive broiler farming model has accelerated the development of the poultry farming industry. However, it has also inevitably brought about many stressors that lead to oxidative stress in the organism. The intestine is the leading site of nutrient digestion, absorption, and metabolism, as well as a secretory and immune organ. Oxidative stress in animal production can harm the intestine, potentially leading to significant losses for the farming industry. Under conditions of oxidative stress, many free radicals are produced in the animal's body, attacking the intestinal mucosal tissues and destroying the barrier integrity of the intestinal tract, leading to disease. Recently, herbs have been shown to have a favorable safety profile and promising application in improving intestinal oxidative stress in poultry. Therefore, future in-depth studies on the specific mechanisms of herbs and their extracts for treating intestinal oxidative stress can provide a theoretical basis for the clinical application of herbs and new therapeutic options for intestinal oxidative stress injury during poultry farming. This review focuses on the causes and hazards of oxidative stress in the intestinal tract of poultry, and on herbs and their extracts with therapeutic potential, to provide a reference for developing and applying new antioxidants.

Role of the Gut Microbiome in Metabolic Dysfunction-Associated Steatotic Liver Disease

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD)-previously described as nonalcoholic fatty liver disease-continues to rise globally. Despite this, therapeutic measures for MASLD remain limited. Recently, there has been a growing interest in the gut microbiome's role in the pathogenesis of MASLD. Understanding this relationship may allow for the administration of therapeutics that target the gut microbiome and/or its metabolic function to alleviate MASLD development or progression. This review will discuss the interplay between the gut microbiome's structure and function in relation to the development of MASLD, assess the diagnostic yield of gut microbiome-based signatures as a noninvasive tool to identify MASLD severity, and examine current and emerging therapies targeting the gut microbiome-liver axis.

Cyclooxygenase-2 (COX-2)-dependent mechanisms mediate sleep responses to microbial and thermal stimuli

Prostaglandins (PGs) play a crucial role in sleep regulation, yet the broader physiological context that leads to the activation of the prostaglandin-mediated sleep-promoting system remains elusive. In this study, we explored sleep-inducing mechanisms potentially involving PGs, including microbial, immune and thermal stimuli as well as homeostatic sleep responses induced by short-term sleep deprivation using cyclooxygenase-2 knockout (COX-2 KO) mice and their wild-type littermates (WT). Systemic administration of 0.4 µg lipopolysaccharide (LPS) induced increased non-rapid-eye movement sleep (NREMS) and fever in WT animals, these effects were completely absent in COX-2 KO mice. This finding underscores the essential role of COX-2-dependent prostaglandins in mediating sleep and febrile responses to LPS. In contrast, the sleep and fever responses induced by tumor necrosis factor α, a proinflammatory cytokine which activates COX-2, were preserved in COX-2 KO animals, indicating that these effects are independent of COX-2-related signaling. Additionally, we examined the impact of ambient temperature on sleep. The sleep-promoting effects of moderate warm ambient temperature were suppressed in COX-2 KO animals, resulting in significantly reduced NREMS at ambient temperatures of 30 °C and 35 °C compared to WT mice. However, rapid-eye-movement sleep responses to moderately cold or warm temperatures did not differ between the two genotypes. Furthermore, 6 h of sleep deprivation induced rebound increases in sleep with no significant differences observed between COX-2 KO and WT mice. This suggests that while COX-2-derived prostaglandins are crucial for the somnogenic effects of increased ambient temperature, the homeostatic responses to sleep loss are COX-2-independent. Overall, the results highlight the critical role of COX-2-derived prostaglandins as mediators of the sleep-wake and thermoregulatory responses to various physiological challenges, including microbial, immune, and thermal stimuli. These findings emphasize the interconnected regulation of body temperature and sleep, with peripheral mechanisms emerging as key players in these integrative processes.

Bacterial lipopolysaccharide inhibits free thiamin uptake along the intestinal tract via interference with membrane expression of thiamin transporters 1 and 2

This study examined the effect of exposure of small and large intestinal epithelial cells to the bacterial lipopolysaccharide (LPS) on uptake of free form of vitamin B1, i.e., thiamin. The intestinal tract encounters two sources of thiamin: diet and the gut microbiota. Absorption of thiamin in both the small and large intestine occurs via a carrier-mediated process that involves thiamin transporters 1 and 2 (THTR-1 and -2). Complementary in vitro (human duodenal epithelial HuTu-80 cells and human colonic epithelial NCM460 cells), in vivo (mice), and ex vivo (human primary differentiated enteroid and colonoid monolayers) models were used. The results showed that exposure to LPS causes a significant inhibition in carrier-mediated [3H]-thiamin uptake by small and large intestinal epithelia, with no change in the levels of expression of THTR-1 and -2 mRNAs and their total cellular proteins. However, a significant decrease in the fractions of the THTR-1 and -2 proteins that are expressed at the cell membranes of these epithelial cells was observed. These effects of LPS appeared to involve a protein kinase A (PKA) signaling pathway as activating this pathway caused a reversal in the inhibition of thiamin uptake and level of expression of its transporters at the cell membrane. These findings demonstrate that exposure of gut epithelia to LPS (a situation that occurs under different pathological conditions) leads to inhibition in thiamin uptake due to a decrease in level of expression of its transporters at the cell membrane that is likely mediated via a PKA signaling pathway. NEW & NOTEWORTHY This study shows that the exposure of gut epithelial cells to bacterial LPS negatively impact the uptake process of the free form of vitamin B1 (i.e., thiamin). This appears to be mediated via suppression in the level of thiamin transporters 1 and 2 (THTR-1 and -2) expression at the cell membrane and involves a protein kinase A (PKA) signaling pathway.

Experimental models of antibiotic exposure and atopic disease

In addition to numerous clinical studies, research using experimental models have contributed extensive evidence to the link between antibiotic exposure and atopic disease. A number of mouse models of allergy have been developed and used to uncover the specific effects of various microbiota members and perturbations on allergy development. Studies in mice that lack microbes entirely have also demonstrated the various components of the immune system that require microbial exposure. The importance of the early-life period and the mechanisms by which atopy "protective" species identified in human cohorts promote immune development have been elucidated in mice. Finally, non-animal models involving human-derived cells shed light on specific effects of bacteria on human epithelial and immune responses. When considered alongside clinical cohort studies, experimental model systems have provided crucial evidence for the link between the neonatal gut microbiota and allergic disease, immensely supporting the stewardship of antibiotic administration in infants. The following review aims to describe the range of experimental models used for studying factors that affect the relationship between the gut microbiota and allergic disease and summarize key findings that have come from research in animal and in vitro models.

GYY4137, as a slow-releasing H2S donor, ameliorates sodium deoxycholate-induced chronic intestinal barrier injury and gut microbiota dysbiosis

Introduction

Numerous studies have revealed that a long-term high-fat diet can raise intestinal deoxycholate acid concentration, which can harm intestinal mucosal barrier function in several ways. This study aims to verify the protective effect of GYY4137, as a slow-releasing H2S donor, on microbiome disturbance and the chronic injury of the intestinal mucosal barrier function caused by sodium deoxycholate.

Methods

Caco-2 monolayer and mouse models were treated with a relatively high concentration of sodium deoxycholate (1.0 mM and 0.2%, respectively) for longer periods (32 h and 12 weeks, respectively) to understand the effects of GYY4137 on sodium deoxycholate-induced chronic intestinal barrier dysfunction and its fundamental mechanisms.

Results

A relatively long period of sodium deoxycholate treatment can remarkably increase the intestinal barrier permeability, alter the distribution and expression of tight junction proteins and generate the production of pro-inflammatory cytokines (TNF-α and IL-1β) in the Caco-2 monolayers and mouse models. Moreover, it can activate the MLCK-P-MLC2 pathway in the Caco-2 monolayers, which was further confirmed using RNA sequencing. The body weight, intestinal barrier histological score, and TUNEL index of sodium deoxycholate-treated mice worsened. In addition, an induced microbiome imbalance was observed in these mice. The above variations can be reversed with the administration of GYY4137.

Conclusion

This study demonstrates that GYY4137 ameliorates sodium deoxycholate-induced chronic intestinal barrier injury by restricting the MLCK-P-MLC2 pathway while elevating the expression level of tight junction proteins, anti-apoptosis and maintaining the microbiome's homeostasis.

Atypical gut microbiota composition in a mouse model of developmental stuttering

Developmental stuttering is a complex neurodevelopmental disorder characterized by disfluent speech. It has been associated with mutations in genes involved in lysosomal enzyme trafficking. Mice with mutations in one such gene, Gnptab, exhibit atypical vocalizations analogous to stuttering in humans. This mouse model has enabled the study of various molecular mechanisms related to the disorder. Simultaneously, an increasing number of reports have suggested the role of gut microbiota in altered brain function and development in neurological disorders. In this study, we compared gut microbiota profiles from Gnptab mutant mice to wildtype control mice. Microbiome analysis demonstrated a distinct microbiota profile in Gnptab mutant mice. The most significant alteration was an increased relative abundance of Akkermansia, a genus of mucin degrading bacteria, which has previously been associated with multiple neurological disorders. Moreover, the altered microbiota profile of these mice was predicted to result in differences in abundance of several metabolic pathways, including short chain fatty acid and lipopolysaccharide synthesis. These pathways may play a role in the onset, progression and persistence of developmental stuttering. This is the first study to show a potential link between developmental stuttering and changes in the gut microbiota, laying the groundwork for a new research direction.

Changes in the Tissue Barrier after Exposure to Lipopolysaccharide on the Apical Side of Enterocytes and the Follicle-Associated Epithelium in Peyer's Patches of the Rat Intestine

To study the para- and transcellular permeability of columnar epithelium and follicle-associated epithelium of Peyer's patches in the rat intestine, LPS was applied from the mucosal side to simulate the action of endotoxins from gram-negative bacteria of gut microbiota. LPS did not affect transepithelial resistance or sodium fluorescein permeability, but increased the levels of claudin-3 and claudin-4 in enterocytes, suggesting strengthening of the paracellular intestinal barrier. Transcellular permeability was evaluated by electron microscopy based on the number of vesicular structures in the cytoplasm of different cell types. LPS increased the number of small vesicles in follicle-associated epithelium of Peyers' patches. In columnar epithelial cells, LPS reduced the number of smaller vesicles and increased the number of larger ones. LPS did not damage the tissue barrier, but enhanced transcytosis, which could potentiate the effects of endotoxin on its receptors in the intestinal mucosa.

Microbiome as an endocrine organ and its relationship with eye diseases: Effective factors and new targeted approaches

Microbiome is an endocrine organ that refers to both the complicated biological system of microbial species that colonize our bodies and their genomes and surroundings. Recent studies confirm the connection between the microbiome and eye diseases, which are involved in the pathogenesis of eye diseases, including age-related macular disorders, diabetic retinopathy, glaucoma, retinitis pigmentosa, dry eye, and uveitis. The aim of this review is to investigate the microbiome in relation to eye health. First, a brief introduction of the characteristics of the gut microorganisms terms of composition and work, the role of dysbiosis, the gut microbiome and the eye microbiome in the progression of eye illnesses are highlighted, then the relationship among the microbiome and the function of the immune system and eye diseases, the role of inflammation and aging and the immune system, It has been reviewed and finally, the control and treatment goals of microbiome and eye diseases, the role of food factors and supplements, biotherapy and antibiotics in relation to microbiome and eye health have been reviewed.

The complex link between the gut microbiome and obesity-associated metabolic disorders: Mechanisms and therapeutic opportunities

Microbial interactions are widespread and important processes that support the link between disease and microbial ecology. The gut microbiota is a major source of microbial stimuli that can have detrimental or beneficial effects on human health. It is also an endocrine organ that maintains energy homeostasis and host immunity. Obesity is a highly and increasingly prevalent metabolic disease and the leading cause of preventable death worldwide. An imbalance in the gut microbiome is associated with several diseases including obesity-related metabolic disorders. This review summarizes the complex association between the gut microbiome and obesity-associated metabolic diseases and validates the role and mechanisms of ecological dysregulation in the gut in obesity-associated metabolic disorders. Therapies that could potentially alleviate obesity-associated metabolic diseases by modulating the gut microbiota are discussed.

Inhibition of colorectal cancer in Alzheimer's disease is mediated by gut microbiota via induction of inflammatory tolerance

Epidemiological studies have revealed an inverse relationship between the incidence of Alzheimer's disease (AD) and various cancers, including colorectal cancer (CRC). We aimed to determine whether the incidence of CRC is reduced in AD-like mice and whether gut microbiota confers resistance to tumorigenesis through inducing inflammatory tolerance using 16S ribosomal RNA gene sequencing and fecal microbiota transplantation (FMT). AD-like mice experienced a significantly decreased incidence of CRC tumorigenesis induced by azoxymethane-dextran sodium sulfate as evidenced by suppressed intestinal inflammation compared with control mice. However, FMT from age-matched control mice reversed the inhibitory effects on the tumorigenesis of CRC and inflammatory response in AD-like mice. The key bacterial genera in gut microbiota, including Prevotella, were increased in both the AD-like mice and in patients with amnestic mild cognitive impairment (aMCI) but were decreased in patients with CRC. Pretreatment with low-dose Prevotella-derived lipopolysaccharides (LPS) induced inflammatory tolerance both in vivo and in vitro and inhibited CRC tumorigenesis in mice. Imbalanced gut microbiota increased intestinal barrier permeability, which facilitated LPS absorption from the gut into the blood, causing cognitive decline in AD-like mice and patients with aMCI. These data reveal that intestinal Prevotella-derived LPS exerts a resistant effect to CRC tumorigenesis via inducing inflammatory tolerance in the presence of AD. These findings provide biological evidence demonstrating the inverse relationship between the incidence of AD and CRC.

Bifidobacterium bifidum Strain BB1 Inhibits Tumor Necrosis Factor-α-Induced Increase in Intestinal Epithelial Tight Junction Permeability via Toll-Like Receptor-2/Toll-Like Receptor-6 Receptor Complex-Dependent Stimulation of Peroxisome Proliferator-Activated Receptor γ and Suppression of NF-κB p65

Bifidobacterium bifidum strain BB1 causes a strain-specific enhancement in intestinal epithelial tight junction (TJ) barrier. Tumor necrosis factor (TNF)-α induces an increase in intestinal epithelial TJ permeability and promotes intestinal inflammation. The major purpose of this study was to delineate the protective effect of BB1 against the TNF-α-induced increase in intestinal TJ permeability and to unravel the intracellular mechanisms involved. TNF-α produces an increase in intestinal epithelial TJ permeability in Caco-2 monolayers and in mice. Herein, the addition of BB1 inhibited the TNF-α increase in Caco-2 intestinal TJ permeability and mouse intestinal permeability in a strain-specific manner. BB1 inhibited the TNF-α-induced increase in intestinal TJ permeability by interfering with TNF-α-induced enterocyte NF-κB p50/p65 and myosin light chain kinase (MLCK) gene activation. The BB1 protective effect against the TNF-α-induced increase in intestinal permeability was mediated by toll-like receptor-2/toll-like receptor-6 heterodimer complex activation of peroxisome proliferator-activated receptor γ (PPAR-γ) and PPAR-γ pathway inhibition of TNF-α-induced inhibitory kappa B kinase α (IKK-α) activation, which, in turn, resulted in a step-wise inhibition of NF-κB p50/p65, MLCK gene, MLCK kinase activity, and MLCK-induced opening of the TJ barrier. In conclusion, these studies unraveled novel intracellular mechanisms of BB1 protection against the TNF-α-induced increase in intestinal TJ permeability. The current data show that BB1 protects against the TNF-α-induced increase in intestinal epithelial TJ permeability via a PPAR-γ-dependent inhibition of NF-κB p50/p65 and MLCK gene activation.

The microbiome-driven impact of western diet in the development of noncommunicable chronic disorders

Noncommunicable chronic disorders (NCDs) are multifactorial disorders that share a state of chronic, low-grade inflammation together with an imbalance of gut microbiota. NCDs are becoming increasingly prevalent worldwide, and mainly in Western countries, with a significant impact on global health. Societal changes, together with the widespread diffusion of modern agricultural methods and food processing, have led to a significant shift in dietary habits over the past century, with an increased diffusion of the Western diet (WD). WD includes foods high in saturated fat, refined sugars, salt, sweeteners, and low in fiber, and is characterized by overeating, frequent snacking, and a prolonged postprandial state. An increasing body of evidence supports the association between the diffusion of WD and the rising prevalence of NCDs. WD also negatively affects both gut microbiota and the immune system by driving to microbial alterations, gut barrier dysfunction, increased intestinal permeability, and leakage of harmful bacterial metabolites into the bloodstream, with consequent contribution to the development of systemic low-grade inflammation. In this review article we aim to dissect the role of gut microbiota imbalance and gut barrier impairment in mediating the detrimental effects of WD on the development of NCDs, and to identify potential therapeutic strategies.

High-intensity interval training and medium-intensity continuous training may affect cognitive function through regulation of intestinal microbial composition and its metabolite LPS by the gut-brain axis

AIMS

The gut-brain axis is the communication mechanism between the gut and the central nervous system, and the intestinal flora and lipopolysaccharide (LPS) play a crucial role in this mechanism. Exercise regulates the gut microbiota composition and metabolite production (i.e., LPS). We aimed to investigate the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on cognitive function in C57BL/6 J mice through gut-brain axis regulation of gut microbiota composition and LPS displacement.

MAIN METHODS

C57BL/6 J male mice were randomly divided into sedentary, HIIT, and MICT groups. After 12 weeks of exercise intervention, the cognitive function of the brain and mRNA levels of related inflammatory factors were measured. RNA sequencing, Golgi staining, intestinal microbial 16 s rDNA sequencing, and ELISA were performed.

KEY FINDINGS

HIIT and MICT affect brain cognitive function by regulating the gut microbiota composition and its metabolite, LPS, through the gut microbiota-gut-brain axis. HIIT is suspected to have a risk: it can induce "intestinal leakage" by regulating intestinal permeability-related microbiota, resulting in excessive LPS in the blood and brain and activating M1 microglia in the brain, leading to reduced dendritic spine density and affecting cognitive function.

SIGNIFICANCE

This study revealed a potential link between changes in the gut microbiota and cognitive function. It highlighted the possible risk of HIIT in reducing dendritic spine density and affecting cognitive function.

Effects of Limosilactobacillus reuteri strains PTA-126787 and PTA-126788 on intestinal barrier integrity and immune homeostasis in an alcohol-induced leaky gut model

Intestinal barrier is a first line of defense that prevents entry of various harmful substances from the lumen into the systemic environment. Impaired barrier function with consequent translocation of harmful substances into systemic circulation ("leaky gut") is a central theme in many gastrointestinal, autoimmune, mental, and metabolic diseases. Probiotics have emerged as a promising strategy to maintain intestinal integrity and address "leaky gut". Using in silico, in vitro and avian in vivo analyses, we previously showed that two novel L. reuteri strains, PTA-126787 (L. reuteri 3630) and PTA-126788 (L. reuteri 3632), isolated from broiler chickens possess favorable safety profiles. Consistent with a recent study, here we show that L. reuteri 3630 and 3632 are phylogenetically similar to human L. reuteri strains. Daily administration of high doses of L. reuteri 3630 and 3632 to Sprague Dawley rats for 28 days was found to be safe with no adverse effects. More importantly, administration of L. reuteri 3630 and 3632 significantly reduced markers associated with alcohol-induced leaky gut, by downregulating inflammatory cytokines and upregulating anti-inflammatory cytokines in an alcohol model of leaky gut in mice. While L. reuteri 3630 cells and supernatant showed no activation, L. reuteri 3632 cells but not supernatant showed activation of AhR, a key transcription factor that regulates gut and immune homeostasis. L. reuteri 3630 is creamish white in morphology typical of Lactobacillus species and L. reuteri 3632 displays a unique orange pigmentation, which was stable even after passaging for 480 generations. We identified a rare polyketide biosynthetic gene cluster in L. reuteri 3632 that likely encodes for the orange-pigmented secondary metabolite. Similar to L. reuteri 3632 cells, the purified orange metabolite activated AhR. All together, these data provide evidence on the phylogenetic relatedness, safety, efficacy, and one of the likely mechanisms of action of L. reuteri 3630 and 3632 for potential probiotic applications to address "leaky gut" and associated pathologies in humans.

Brain-Gut and Microbiota-Gut-Brain Communication in Type-2 Diabetes Linked Alzheimer's Disease

The gastrointestinal (GI) tract, home to the largest microbial population in the human body, plays a crucial role in overall health through various mechanisms. Recent advancements in research have revealed the potential implications of gut-brain and vice-versa communication mediated by gut-microbiota and their microbial products in various diseases including type-2 diabetes and Alzheimer's disease (AD). AD is the most common type of dementia where most of cases are sporadic with no clearly identified cause. However, multiple factors are implicated in the progression of sporadic AD which can be classified as non-modifiable (e.g., genetic) and modifiable (e.g. Type-2 diabetes, diet etc.). Present review focusses on key players particularly the modifiable factors such as Type-2 diabetes (T2D) and diet and their implications in microbiota-gut-brain (MGB) and brain-gut (BG) communication and cognitive functions of healthy brain and their dysfunction in Alzheimer's Disease. Special emphasis has been given on elucidation of the mechanistic aspects of the impact of diet on gut-microbiota and the implications of some of the gut-microbial products in T2D and AD pathology. For example, mechanistically, HFD induces gut dysbiosis with driven metabolites that in turn cause loss of integrity of intestinal barrier with concomitant colonic and systemic chronic low-grade inflammation, associated with obesity and T2D. HFD-induced obesity and T2D parallel neuroinflammation, deposition of Amyloid β (Aβ), and ultimately cognitive impairment. The review also provides a new perspective of the impact of diet on brain-gut and microbiota-gut-brain communication in terms of transcription factors as a commonly spoken language that may facilitates the interaction between gut and brain of obese diabetic patients who are at a higher risk of developing cognitive impairment and AD. Other commonality such as tyrosine kinase expression and functions maintaining intestinal integrity on one hand and the phagocytic clarence by migratory microglial functions in brain are also discussed. Lastly, the characterization of the key players future research that might shed lights on novel potential pharmacological target to impede AD progression are also discussed.

FXR deletion attenuates intestinal barrier dysfunction in murine acute intestinal inflammation

Accumulating literature suggests that the farnesoid-X receptor (FXR), a nuclear bile acid receptor best known for its role in bile acid homeostasis, is also a potent context-dependent regulator of inflammation. FXR may thus be relevant to several intestinal disease states including inflammatory bowel disease, necrotizing enterocolitis, and sepsis. In this study, we tested the effects of FXR deletion on acute murine intestinal inflammation. We found that FXR knockout (KO) mice were protected from intestinal injury and barrier dysfunction induced by lipopolysaccharide (LPS) injection, dithizone (DI)/Klebsiella, and cecal ligation/puncture models. In the LPS model, RNA sequencing and qPCR analysis showed that this protection correlated with substantial reduction in LPS-induced proinflammatory gene expression, including lower tissue levels of Il1a, Il1b, and Tnf. Examining functional effects on the epithelium, we found that LPS-induced tight junctional disruption as assessed by internalization of ZO-1 and occludin was ameliorated in FXR KO animals. Taken together, these data suggest a role for FXR in the intestinal barrier during inflammatory injury.NEW & NOTEWORTHY Intestinal barrier failure is a hallmark in gut-origin sepsis. We demonstrate that the intestinal barriers of farnesoid-X receptor (FXR) knockout (KO) animals are protected from inflammatory insult using multiple models of acute intestinal inflammation. This protection is due to decreased inflammatory cytokine production and maintenance of tight junctional architecture seen within the KO animals. This is the first report of FXR deletion being protective to the intestinal barrier.

Intestinal Epithelial Co-Culture Sensitivity to Pro-Inflammatory Stimuli and Polyphenols Is Medium-Independent

The complexification of in vitro models requires the compatibility of cells with the same medium. Since immune cells are the most sensitive to growth conditions, growing intestinal epithelial cells in their usual medium seems to be necessary. This work was aimed at comparing the sensitivity of these epithelial cells to pro-inflammatory stimuli but also to dietary polyphenols in both DMEM and RPMI-1640 media. Co-cultures of Caco-2 and HT29-MTX cells were grown for 21 days in the two media before their stimulation with a cocktail of TNF-α (20 ng/mL), IL-1β (1 ng/mL), and IFN-γ (10 ng/mL) or with LPS (10 ng/mL) from E. coli (O111:B4). The role of catechins (15 µM), a dietary polyphenol, was evaluated after its incubation with the cells before their stimulation for 6 h. The RPMI-1640 medium did not alter the intensity of the inflammatory response observed with the cytokines. By contrast, LPS failed to stimulate the co-culture in inserts regardless of the medium used. Lastly, catechins were unable to prevent the pro-inflammatory response observed with the cytokines in the two media. The preservation of the response of this model of intestinal epithelium in RPMI-1640 medium is promising when considering its complexification to evaluate the complex cellular crosstalk leading to intestinal homeostasis.

Gut microbiota DPP4-like enzymes are increased in type-2 diabetes and contribute to incretin inactivation

BACKGROUND

The gut microbiota controls broad aspects of human metabolism and feeding behavior, but the basis for this control remains largely unclear. Given the key role of human dipeptidyl peptidase 4 (DPP4) in host metabolism, we investigate whether microbiota DPP4-like counterparts perform the same function.

RESULTS

We identify novel functional homologs of human DPP4 in several bacterial species inhabiting the human gut, and specific associations between Parabacteroides and Porphyromonas DPP4-like genes and type 2 diabetes (T2D). We also find that the DPP4-like enzyme from the gut symbiont Parabacteroides merdae mimics the proteolytic activity of the human enzyme on peptide YY, neuropeptide Y, gastric inhibitory polypeptide (GIP), and glucagon-like peptide 1 (GLP-1) hormones in vitro. Importantly, administration of E. coli overexpressing the P. merdae DPP4-like enzyme to lipopolysaccharide-treated mice with impaired gut barrier function reduces active GIP and GLP-1 levels, which is attributed to increased DPP4 activity in the portal circulation and the cecal content. Finally, we observe that linagliptin, saxagliptin, sitagliptin, and vildagliptin, antidiabetic drugs with DPP4 inhibitory activity, differentially inhibit the activity of the DPP4-like enzyme from P. merdae.

CONCLUSIONS

Our findings confirm that proteolytic enzymes produced by the gut microbiota are likely to contribute to the glucose metabolic dysfunction that underlies T2D by inactivating incretins, which might inspire the development of improved antidiabetic therapies.

Bacterial peptidoglycan serves as a critical modulator of the gut-immune-brain axis in Drosophila

Metabolites and compounds derived from gut-associated bacteria can modulate numerous physiological processes in the host, including immunity and behavior. Using a model of oral bacterial infection, we previously demonstrated that gut-derived peptidoglycan (PGN), an essential constituent of the bacterial cell envelope, influences female fruit fly egg-laying behavior by activating the NF-κB cascade in a subset of brain neurons. These findings underscore PGN as a potential mediator of communication between gut bacteria and the brain in Drosophila, prompting further investigation into its impact on all brain cells. Through high-resolution mass spectrometry, we now show that PGN fragments produced by gut bacteria can rapidly reach the central nervous system. In Addition, by employing a combination of whole-genome transcriptome analyses, comprehensive genetic assays, and reporter gene systems, we reveal that gut bacterial infection triggers a PGN dose-dependent NF-κB immune response in perineurial glia, forming the continuous outer cell layer of the blood-brain barrier. Furthermore, we demonstrate that persistent PGN-dependent NF-κB activation in perineurial glial cells correlates with a reduction in lifespan and early neurological decline. Overall, our findings establish gut-derived PGN as a critical mediator of the gut-immune-brain axis in Drosophila.

Improved Gut Health May Be a Potential Therapeutic Approach for Managing Prediabetes: A Literature Review

Given the growing global threat and rising prevalence of type 2 diabetes mellitus (T2DM), addressing this metabolic disease is imperative. T2DM is preceded by prediabetes (PD), an intermediate hyperglycaemia that goes unnoticed for years in patients. Several studies have shown that gut microbial diversity and glucose homeostasis in PD or T2DM patients are affected. Therefore, this review aims to synthesize the existing literature to elucidate the association between high-calorie diets, intestinal permeability and their correlation with PD or T2DM. Moreover, it discusses the beneficial effects of different dietary interventions on improving gut health and glucose metabolism. The primary factor contributing to complications seen in PD or T2DM patients is the chronic consumption of high-calorie diets, which alters the gut microbial composition and increases the translocation of toxic substances from the intestinal lumen into the bloodstream. This causes an increase in inflammatory response that further impairs glucose regulation. Several dietary approaches or interventions have been implemented. However, only a few are currently in use and have shown promising results in improving beneficial microbiomes and glucose metabolism. Therefore, additional well-designed studies are still necessary to thoroughly investigate whether improving gut health using other types of dietary interventions can potentially manage or reverse PD, thereby preventing the onset of T2DM.

The Importance of Maintaining and Improving a Healthy Gut Microbiota in Athletes as a Preventive Strategy to Improve Heat Tolerance and Acclimatization

Exposure to passive heat (acclimation) and exercise under hot conditions (acclimatization), known as heat acclimation (HA), are methods that athletes include in their routines to promote faster recovery and enhance physiological adaptations and performance under hot conditions. Despite the potential positive effects of HA on health and physical performance in the heat, these stimuli can negatively affect gut health, impairing its functionality and contributing to gut dysbiosis. Blood redistribution to active muscles and peripheral vascularization exist during exercise and HA stimulus, promoting intestinal ischemia. Gastrointestinal ischemia can impair intestinal permeability and aggravate systemic endotoxemia in athletes during exercise. Systemic endotoxemia elevates the immune system as an inflammatory responses in athletes, impairing their adaptive capacity to exercise and their HA tolerance. Better gut microbiota health could benefit exercise performance and heat tolerance in athletes. This article suggests that: (1) the intestinal modifications induced by heat stress (HS), leading to dysbiosis and altered intestinal permeability in athletes, can decrease health, and (2) a previously acquired microbial dysbiosis and/or leaky gut condition in the athlete can negatively exacerbate the systemic effects of HA. Maintaining or improving the healthy gut microbiota in athletes can positively regulate the intestinal permeability, reduce endotoxemic levels, and control the systemic inflammatory response. In conclusion, strategies based on positive daily habits (nutrition, probiotics, hydration, chronoregulation, etc.) and preventing microbial dysbiosis can minimize the potentially undesired effects of applying HA, favoring thermotolerance and performance enhancement in athletes.

Biogenic selenium nanoparticles alleviate intestinal barrier injury in mice through TBC1D15/Fis1/Rab7 pathway

Intestinal diseases often stem from a compromised intestinal barrier. This barrier relies on a functional epithelium and proper turnover of intestinal cells, supported by mitochondrial health. Mitochondria and lysosomes play key roles in cellular balance. Our previous researches indicate that biogenic selenium nanoparticles (SeNPs) can alleviate intestinal epithelial barrier damage by enhancing mitochondria-lysosome crosstalk, though the detailed mechanism is unclear. This study aimed to investigate the role of mitochondria-lysosome crosstalk in the protective effect of SeNPs on intestinal barrier function in mice exposed to lipopolysaccharide (LPS). The results showed that LPS exposure increased intestinal permeability in mice, leding to structural and functional damage to mitochondrial and lysosomal. Oral administration of SeNPs significantly upregulated the expression levels of TBC1D15 and Fis1, downregulated the expression levels of Rab7, Caspase-3, Cathepsin B, and MCOLN2, effectively alleviated LPS-induced mitochondrial and lysosomal dysfunction and maintained the intestinal barrier integrity in mice. Furthermore, SeNPs notably inhibited mitophagy caused by adenovirus-associated virus (AAV)-mediated RNA interference the expression of TBC1D15 in the intestine of mice, maintained mitochondrial and lysosomal homeostasis, and effectively alleviated intestinal barrier damage. These results suggested that SeNPs can regulate mitochondria-lysosome crosstalk and inhibit its damage by regulating the TBC1D15/Fis1/Rab7- signaling pathway. thereby alleviating intestinal barrier damage. It lays a theoretical foundation for elucidating the mechanism of mitochondria-lysosome crosstalk in regulating intestinal barrier damage and repair, and provides new ideas and new ways to establish safe and efficient nutritional regulation strategies to prevent and treat intestinal diseases caused by inflammation.

Western diet components that increase intestinal permeability with implications on health

Intestinal permeability is a physiological property that allows necessary molecules to enter the organism. This property is regulated by tight junction proteins located between intestinal epithelial cells. However, various factors can increase intestinal permeability (IIP), including diet. Specific components in the Western diet (WD), such as monosaccharides, fat, gluten, salt, alcohol, and additives, can affect the tight junctions between enterocytes, leading to increased permeability. This review explains how these components promote IIP and outlines their potential implications for health. In addition, we describe how a reduction in WD consumption may help improve dietary treatment of diseases associated with IIP. Research has shown that some of these components can cause changes in the gut microbiota, leading to dysbiosis, which can promote greater intestinal permeability and displacement of endotoxins into the bloodstream. These endotoxins include lipopolysaccharides derived from gram-negative bacteria, and their presence has been associated with various diseases, such as autoimmune, neurological, and metabolic diseases like diabetes and cardiovascular disease. Therefore, nutrition professionals should promote the reduction of WD consumption and consider the inclusion of healthy diet components as part of the nutritional treatment for diseases associated with increased intestinal permeability.

Exploring the therapeutic potential of cinnamoyl derivatives in attenuating inflammation in lipopolysaccharide-induced Caco-2 cells

Aim: In gastrointestinal (GI) diseases, lipopolysaccharide (LPS) exacerbates gut-barrier dysfunction and inflammation. Cinnamoyl derivatives show potential in mitigating LPS-induced inflammation.Materials & methods: We assessed intestinal epithelial barrier function using Trans-epithelial electrical resistance values and measured inflammatory mediators through real-time PCR and ELISA in Caco-2 cells.Results: LPS treatment increased IL-6, IL-1β, TNF-α, PGE2 and TRL4 expression in Caco-2 cells. Pre-treatment with DM1 (1 or 10 μM) effectively countered LPS-induced TLR4 overexpression and reduced IL-6, IL-1β, TNF-α and PGE2 levels.Conclusion: DM1 holds promise in regulating inflammation and maintaining intestinal integrity by suppressing TLR4 and inflammatory mediators in Caco-2 cells. These findings suggest a potential therapeutic avenue for GI diseases.

Role of sulfidogenic members of the gut microbiota in human disease

The human gut flora comprises a dynamic network of bacterial species that coexist in a finely tuned equilibrium. The interaction with intestinal bacteria profoundly influences the host's development, metabolism, immunity, and overall health. Furthermore, dysbiosis, a disruption of the gut microbiota, can induce a variety of diseases, not exclusively associated with the intestinal tract. The increased consumption of animal protein, high-fat and high-sugar diets in Western countries has been implicated in the rise of chronic and inflammatory illnesses associated with dysbiosis. In particular, this diet leads to the overgrowth of sulfide-producing bacteria, known as sulfidogenic bacteria, which has been linked to inflammatory bowel diseases and colorectal cancer, among other disorders. Sulfidogenic bacteria include sulfate-reducing bacteria (Desulfovibrio spp.) and Bilophila wadsworthia among others, which convert organic and inorganic sulfur compounds to sulfide through the dissimilatory sulfite reduction pathway. At high concentrations, sulfide is cytotoxic and disrupts the integrity of the intestinal epithelium and mucus barrier, triggering inflammation. Besides producing sulfide, B. wadsworthia has revealed significant pathogenic potential, demonstrated in the ability to cause infection, adhere to intestinal cells, promote inflammation, and compromise the integrity of the colonic mucus layer. This review delves into the mechanisms by which taurine and sulfide-driven gut dysbiosis contribute to the pathogenesis of sulfidogenic bacteria, and discusses the role of these gut microbes, particularly B. wadsworthia, in human diseases.

Study on the Protective Effect and Mechanism of Umbilicaria esculenta Polysaccharide in DSS-Induced Mice Colitis and Secondary Liver Injury

This study aimed to explore the ameliorative effects and potential mechanisms of Huangshan Umbilicaria esculenta polysaccharide (UEP) in dextran sulfate sodium-induced acute ulcerative colitis (UC) and UC secondary liver injury (SLI). Results showed that UEP could ameliorate both colon and liver pathologic injuries, upregulate mouse intestinal tight junction proteins (TJs) and MUC2 expression, and reduce LPS exposure, thereby attenuating the effects of the gut-liver axis. Importantly, UEP significantly downregulated the secretion levels of TNF-α, IL-1β, and IL-6 through inhibition of the NF-κB pathway and activated the Nrf2 signaling pathway to increase the expression levels of SOD and GSH-Px. In vitro, UEP inhibited the LPS-induced phosphorylation of NF-κB P65 and promoted nuclear translocation of Nrf2 in RAW264.7 cells. These results revealed that UEP ameliorated UC and SLI through NF-κB and Nrf2-mediated inflammation and oxidative stress. The study first investigated the anticolitis effect of UEP, suggesting its potential for the treatment of colitis and colitis-associated liver disease.

Systemic LPS Administration Stimulates the Activation of Non-Neuronal Cells in an Experimental Model of Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by deficiency of the survival motor neuron (SMN) protein. Although SMA is a genetic disease, environmental factors contribute to disease progression. Common pathogen components such as lipopolysaccharides (LPS) are considered significant contributors to inflammation and have been associated with muscle atrophy, which is considered a hallmark of SMA. In this study, we used the SMNΔ7 experimental mouse model of SMA to scrutinize the effect of systemic LPS administration, a strong pro-inflammatory stimulus, on disease outcome. Systemic LPS administration promoted a reduction in SMN expression levels in CNS, peripheral lymphoid organs, and skeletal muscles. Moreover, peripheral tissues were more vulnerable to LPS-induced damage compared to CNS tissues. Furthermore, systemic LPS administration resulted in a profound increase in microglia and astrocytes with reactive phenotypes in the CNS of SMNΔ7 mice. In conclusion, we hereby show for the first time that systemic LPS administration, although it may not precipitate alterations in terms of deficits of motor functions in a mouse model of SMA, it may, however, lead to a reduction in the SMN protein expression levels in the skeletal muscles and the CNS, thus promoting synapse damage and glial cells' reactive phenotype.

Good girl goes bad: Understanding how gut commensals cause disease

This review examines the complex connection between commensal microbiota and the development of opportunistic infections. Several underlying conditions, such as metabolic diseases and weakened immune systems, increase the vulnerability of patients to opportunistic infections. The increasing antibiotic resistance adds significant complexity to the management of infectious diseases. Although commensals have long been considered beneficial, recent research contradicts this notion by uncovering chronic illnesses linked to atypical pathogens or commensal bacteria. This review examines conditions in which commensal bacteria, which are usually beneficial, contribute to developing diseases. Commensals' support for opportunistic infections can be categorized based on factors such as colonization fitness, pathoadaptive mutation, and evasion of host immune response. Individuals with weakened immune systems are especially susceptible, highlighting the importance of mucosal host-microbiota interaction in promoting infection when conditions are inappropriate. Dysregulation of gut microbial homeostasis, immunological modulation, and microbial interactions are caused by several factors that contribute to the development of chronic illnesses. Knowledge about these mechanisms is essential for developing preventive measures, particularly for susceptible populations, and emphasizes the importance of maintaining a balanced gut microbiota in reducing the impact of opportunistic infections.

Black rice anthocyanins nanoparticles based on bovine serum albumin and hyaluronic acid: Preparation, characterization, absorption and intestinal barrier function protection in Caco-2 monolayers

Black rice anthocyanins (BRA) nanoparticles (NPs) were prepared using hyaluronic acid (HA), oxidized hyaluronic acid (OHA) and bovine serum albumin (BSA) to enhance the absorption and bioactivity of anthocyanins (ACNs). Results showed that HA/OHA-BSA-BRA NPs had a spherical morphology and excellent dispensability, with hydrated radius ~ 500 nm, zeta potential ~ - 30 mV, and encapsulation efficiency ~21 %. Moreover, using in vitro gastrointestinal release assay, we demonstrated that both BRA-loaded NPs exhibited effective controlled release properties of ACNs, significantly enhancing the accessibility of ACNs to the intestine. Cellular experiments showed that both two NPs had good biocompatibility and increased uptake of BRA. Furthermore, in comparison to the free BRA group, both BRA NPs groups significantly decreased the TEER value and increased the expression of tight junction proteins (Claudin 1, Occludin and ZO-1) in Caco-2 cell monolayers with LPS-induced damage. Therefore, our study demonstrated that HA/OHA-BSA-BRA NPs are promising carriers of ACNs and can effectively prevent the LPS-induced intestinal barrier injury in vitro.

Fructooligosaccharides act on the gut-bone axis to improve bone independent of Tregs and alter osteocytes in young adult C57BL/6 female mice

Targeting the gut-bone axis with probiotics and prebiotics is considered as a promising strategy to reduce the risk of osteoporosis. Gut-derived short chain fatty acids (SCFA) mediate the effects of probiotics on bone via Tregs, but it is not known whether prebiotics act through a similar mechanism. We investigated how 2 different prebiotics, tart cherry (TC) and fructooligosaccharide (FOS), affect bone, and whether Tregs are required for this response. Eight-wk-old C57BL/6 female mice were fed with diets supplemented with 10% w/w TC, FOS, or a control diet (Con; AIN-93M) diet, and they received an isotype control or CD25 Ab to suppress Tregs. The FOS diet increased BMC, density, and trabecular bone volume in the vertebra (~40%) and proximal tibia (~30%) compared to the TC and control diets (Con), irrespective of CD25 treatment. Both prebiotics increased (P < .01) fecal SCFAs, but the response was greater with FOS. To determine how FOS affected bone cells, we examined genes involved in osteoblast and osteoclast differentiation and activity as well as genes expressed by osteocytes. The FOS increased the expression of regulators of osteoblast differentiation (bone morphogenetic protein 2 [Bmp2], Wnt family member 10b [Wnt10b] and Osterix [Osx]) and type 1 collagen). Osteoclasts regulators were unaltered. The FOS also increased the expression of genes associated with osteocytes, including (Phex), matrix extracellular phosphoglycoprotein (Mepe), and dentin matrix acidic phosphoprotein 1 (Dmp-1). However, Sost, the gene that encodes for sclerostin was also increased by FOS as the number and density of osteocytes increased. These findings demonstrate that FOS has a greater effect on the bone mass and structure in young adult female mice than TC and that its influence on osteoblasts and osteocytes is not dependent on Tregs.

The accessible chromatin landscape of lipopolysaccharide-induced systemic inflammatory response identifying epigenome signatures and transcription regulatory networks in chickens

Lipopolysaccharide (LPS) can induce systemic inflammatory response (SIR) in animals. Understanding the regulatory mechanism of SIR and therapies to ensure healthy growth is urgently needed. Chromatin remodeling plays a crucial role in the expression of genes involved in immune diseases. In the present study, the ATAC-seq analysis revealed 3491 differential open chromatin sites in the spleen of chicks with SIR induced by LPS challenge, and we presented the motifs on these sites and the associated transcription factors. The regulatory network was presented by combining the differential open chromatin data with the mRNAs and exploded cytokines. Interestingly, the LPS challenge could regulate the mRNA expression of 202 genes through chromatin reprogramming, including critical genes such as TLE1 and JUN, which regulate signaling pathways such as I-κB kinase/NF-κB, Toll-like receptor, and downstream cytokine genes. Furthermore, dietary daidzein could inhibit DNA topoisomerase II, which reprograms the spatial conformation of chromatin in the inflammatory response and attenuates SIR. In conclusion, we successfully identified key genes directly regulated by chromatin reprogramming in SIR and demonstrated the chromatin epigenome signatures and transcriptional regulatory network, which provides an important reference for further research on avian epigenetics. There is great potential for alleviating SIR using dietary daidzein.

Diet-Induced Gut Dysbiosis and Leaky Gut Syndrome

Chronic gut inflammation promotes the development of metabolic diseases such as obesity. There is growing evidence which suggests that dysbiosis in gut microbiota and metabolites disrupt the integrity of the intestinal barrier and significantly impact the level of inflammation in various tissues, including the liver and adipose tissues. Moreover, dietary sources are connected to the development of leaky gut syndrome through their interaction with the gut microbiota. This review examines the effects of these factors on intestinal microorganisms and the communication pathways between the gut-liver and gut-brain axis. The consumption of diets rich in fats and carbohydrates has been found to weaken the adherence of tight junction proteins in the gastrointestinal tract. Consequently, this allows endotoxins, such as lipopolysaccharides produced by detrimental bacteria, to permeate through portal veins, leading to metabolic endotoxemia and alterations in the gut microbiome composition with reduced production of metabolites, such as short-chain fatty acids. However, the precise correlation between gut microbiota and alternative sweeteners remains uncertain, necessitating further investigation. This study highlights the significance of exploring the impact of diet on gut microbiota and the underlying mechanisms in the gut-liver and gut-brain axis. Nevertheless, limited research on the gut-liver axis poses challenges in comprehending the intricate connections between diet and the gut-brain axis. This underscores the need for comprehensive studies to elucidate the intricate gut-brain mechanisms underlying intestinal health and microbiota.