Surfactin Mitigates Dextran Sodium Sulfate-Induced Colitis and Behavioral Disorders in Mice by Mediating Gut-Brain-Axis Balance

Microbiome-driven precision medicine: advancing drug development with pharmacomicrobiomics

Pharmacomicrobiomics investigates the complicated relationship between the gut microbiome and medications. Microbial communities can influence the metabolism and efficacy of many medications in two primary ways: directly and indirectly. Direct mechanisms typically entail the induction of biochemical alterations and multiple transformations directly on the drug, whereas indirect mechanisms encompass modifications in host metabolism, alterations in the gut microbial community, the synthesis of various metabolites, and interactions with the host immune system, which indirectly influence the drug's metabolism, absorption, and efficacy. For instance, microbial communities play an important part in activating prodrugs like sulfasalazine, improving the outcomes of immunotherapy, and minimising toxicity through specific interventions. Nonetheless, barriers can also emerge from the microbial breakdown of medications, reducing their therapeutic efficacy, along with adverse reactions mediated by microbiota. Innovations like probiotics, faecal microbiota transplantation, and microbiota profiling have shown promise in enhancing these interactions. Utilising the distinct microbiota composition of individuals, pharmacomicrobiomics offers a route to personalised, precise, and safer therapies, signalling an important evolution in drug development and clinical practice. This study aims to provide a comprehensive overview of microbiome-drug interactions.

Medium-Chain Chlorinated Paraffins Altered Neurobehavior and Induced Neuroinflammation Associated with Disordered Intestinal Homeostasis

Chlorinated paraffins, derivatives of chlorinated n-alkanes, are widely used in agricultural and industrial applications. With the restriction of short-chain chlorinated paraffins (SCCPs), the use of medium-chain chlorinated paraffins (MCCPs) has sharply increased. MCCPs have recently been detected in foods and animal brains, raising concerns about their health effects. However, their impact on intestinal homeostasis and the nervous system is poorly understood. In this study, neurobehavioral, metabolomics, histopathology, inflammatory responses, gut microbiota, and derived metabolites were evaluated after CP-52 (a commercially prevalent MCCP) exposure. The results showed that CP-52 induced abnormal behaviors, reduced gray matter thickness, activated astrocytes, and triggered neuroinflammation. Concurrently, CP-52 significantly altered gut microbiota, reduced short-chain fatty acid (SCFAs) levels, and promoted intestinal inflammation, potentially contributing to neuroinflammation via the microbiota-gut-brain axis. These findings will provide important insights into the safety assessment of MCCPs.

Beta-Sitosterol-Conjugated Sinapic Acid-Engineered Nanoliposome: Biomucoadhesive and Enzyme-Responsive Targeted Oral Therapy in Ulcerative Colitis

Developing oral drug delivery systems is promising for ulcerative colitis (UC). However, the key challenges, including formulation degradation under harsh gastric conditions, poor targeting efficiency, and limited colonic residence, lead to poor therapeutic efficacy that still needs to be tackled. Effective treatment requires a safe, efficacious, enzyme- and pH-responsive, biomucoadhesive oral drug delivery system to overcome these challenges. Therefore, we have developed chitosan-armored 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) nanoliposomes amalgamated with synthesized beta-sitosterol-sinapic acid (Be-S) conjugate, further encapsulated with 3,4-methylenedioxy-β-nitrostyrene (MNS) as NLRP3 inhibitor, termed C@MN@DMBe-S, to overcome the limitation of free MNS and sinapic acid. Formulated by the thin-film hydration method and processed through extrusion, these unilamellar liposomes demonstrated structural stability and mucoadhesive properties due to chitosan coating. This configuration protected the nanoliposomes from the gastric acidic environment and allowed retention in the inflamed colon for 48 h. The enzyme-responsive C@MN@DMBe-S nanoliposome releases sinapic acid at the inflamed colonic site via esterase activity, providing sustained and controlled release of MNS. This synergistic action delivers antioxidant and anti-inflammatory effects while influencing the gut microbiota composition by releasing short-chain fatty acids. Moreover, therapeutic investigations revealed that C@MN@DMBe-S exhibited superior efficacy compared with free MNS when administered orally. The formulation effectively downregulated NF-κB, NLRP3, Caspase-1, and IL-1β expression while upregulating MUC5AC expression, indicating enhanced anti-inflammatory and protective effects and thereby promoting mucosal healing. In addition, C@MN@DMBe-S was found to regulate immune cell expression and effectively downregulate neutrophil infiltration. This armor- and enzyme-responsive strategy elucidates the impact of oral nanomedicines on mitigating UC and is demonstrated as an effective treatment.

Surfactin inhibits enterococcal biofilm formation via interference with pilus and exopolysaccharide biosynthesis

Enterococcus faecalis is a significant pathogen in healthcare settings and is frequently resistant to multiple antibiotics. This resistance is compounded by its ability to form biofilms, dense bacterial communities that are challenging to eliminate via standard antibiotic therapies. As such, targeting biofilm formation is considered a viable strategy for addressing these infections. This study assessed the effectiveness of surfactin, a cyclic lipopeptide biosurfactant synthesized by Bacillus subtilis natto NTU-18, in preventing biofilm formation by E. faecalis. Analytical characterization of surfactin was performed via liquid chromatography‒mass spectrometry (LC‒MS). Additionally, transcriptomic sequencing and quantitative PCR (qPCR) were used to investigate alterations in E. faecalis gene expression following treatment with surfactin. The data revealed notable suppression of crucial virulence-related genes responsible for pilus construction and exopolysaccharide synthesis, both of which are vital for E. faecalis adhesion and biofilm structure. Functional tests confirmed that surfactin treatment substantially reduced E. faecalis attachment to Caco-2 cell monolayers and curtailed exopolysaccharide production. Moreover, confocal laser scanning microscopy revealed significant thinning of the biofilms. These observations support the potential utility of surfactin as a therapeutic agent to manage biofilm-associated infections caused by E. faecalis.

Structural Characterization of Water-Soluble Pectin from the Fruit of Diospyros lotus L. and Its Protective Effects against DSS-Induced Colitis in Mice

Polysaccharides from Diospyros lotus L. were investigated for their structural characterization and anti-inflammatory activity. Four low polymer dispersity index (PDI) subfractions were obtained: DRP-1 (153.95 kDa), DRP-2 (61.22 kDa), DRP-3 (22.80 kDa), and DRP-4 (8.93 kDa), respectively. DRP-4 contained the highest number of RG-I domains (43.25%), while DRP-1 had the highest degree of methyl esterification (37.5%). Results from the dextran sulfate sodium (DSS) salt-induced ulcerative colitis (UC) mice model indicated that DCP promoted mucosal and tight junction protein (caudin-1 and occludin) expression. Moreover, DCP improved the microbial community composition through selective enrichment of beneficial bacteria such as Lachnospiraceae and Lactobacillaceae. The anti-inflammatory activity of DCP was speculated to be related to its neutral sugar side chain and low esterification degree. These results suggested that DCP could prevent DSS-induced colitis and inhibit colon inflammation by maintaining a balanced gut microbiome and protecting the colon mucosal barrier.

Surfactin's impact on gut microbiota and intestinal tumor cells

Surfactin exhibits multifunctional properties, including antimicrobial, anti-inflammatory, and antitumor activities, positioning it as a promising novel food additive. However, its specific effects on the gut environment remain largely unexplored. To investigate this, we conducted in vitro fermentation simulations to assess the impact of surfactin on gut microbiota. Additionally, we evaluated surfactin's inhibitory effects on HCT-116 cells. The results of the fermentation simulation indicated that surfactin significantly increased butyrate production and enhanced the relative abundance of Megamonas, Alistipes, the Oscillospiraceae NK4A214 group, and Methanobrevibacter smithii, while markedly inhibiting Desulfobacterota, potentially facilitating amino acid and lipid metabolism. Furthermore, surfactin significantly inhibited the proliferation of HCT-116 cells and promoted their apoptosis, without exhibiting cytotoxicity towards normal human intestinal epithelial crypt (HIEC) cells. In summary, surfactin demonstrates a favorable safety profile in the intestinal environment. This study contributes to our understanding of the interaction between surfactin and the gut environment.

Bacillus amyloliquefaciens SC06 alleviates LPS-induced intestinal damage by inhibiting endoplasmic reticulum stress and mitochondrial dysfunction in piglets

Endoplasmic reticulum stress (ERS) and mitochondrial dysfunction play an important role in the pathogenesis of intestinal diseases. Our studies investigated the effects of Bacillus amyloliquefaciens SC06 on jejunal mitochondria and ER in piglets under the LPS-induced intestinal injury model. Eighteen piglets (male, 21 days old) were randomly assigned to three treatments: CON (basal diet), LPS (basal diet +100 μg/kg LPS), and SC06 + LPS (basal diet +1 × 108 cfu/kg SC06 + 100 μg/kg LPS). Compared to the LPS group, administration of SC06 improved jejunal morphology and barrier function. In addition, SC06 reduced reactive oxygen species (ROS) and MDA generation in the jejunum by activating the Nrf2/keap1 pathway, which increased the activity of CAT, GSH and SOD in LPS-challenged pigs. In addition, SC06 reduced LPS-induced mitochondrial dysfunction and ERS as evidenced by a decrease in ROS, an improvement in mitochondrial membrane potential and an increase in adenosine triphosphate levels. The results of in vitro IPEC-J2 cell experiments also indicate that SC06 can reduce LPS-induced oxidative stress, mitochondrial dysfunction, ERS, and intestinal barrier function damage by activating the Nrf2/keap1 signaling pathway. Finally, treatment with the Nrf2-specific inhibitor ML-385 inhibited the upregulated effect of SC06 on antioxidant capacity and intestinal barrier function in IPEC-J2 cells. In conclusion, SC06 ameliorated intestinal damage and mitochondrial dysfunction and attenuated endoplasmic reticulum stress via activation of the Nrf2/keap1 signaling pathway in LPS-challenged piglets.

Surfactin from Bacillus subtilis enhances immune response and contributes to the maintenance of intestinal microbial homeostasis

Surfactin, a lipopeptide biosurfactant produced by Bacillus spp., has emerged as a promising bioactive compound due to its potent inhibitory effects on bacterial and viral pathogens. This showcases its potential as a non-antibiotic strategy for managing infectious diseases. Our investigation reveals that surfactin administration significantly promotes weight gain and improves immune organ indices in mice, reflecting enhanced immunity and gut health. Surfactin augments phagocytic function in peritoneal macrophages and boosts proliferative responses in splenic lymphocytes post-chicken red blood cell immunization. Furthermore, it increases intestinal villi height, indicative of superior nutrient absorption. It elevates mucin secretion and expression of intestinal mucosal proteins, such as secretory IgA, Muc1, and Muc2, and tight junction proteins claudin-1, occludin, and Zo-1 in the jejunum and colon. Crucially, surfactin modifies the gut microbiota composition by reducing Escherichia coli populations and ameliorating cyclophosphamide-induced gut dysbiosis. Our data suggest that oral surfactin could be a valuable therapeutic modality to alleviate immune suppression and gut damage, proposing a new pathway for immunomodulatory treatment.

IMPORTANCE

The potential of surfactin as a microbial surfactant extends beyond its surfactant properties, impacting immune regulation and gut health. As the need for alternatives to traditional antibiotics continues to grow, surfactin's ability to enhance host defense mechanisms against common pathogens without directly targeting them with antibiotics offers a strategic advantage. Understanding how surfactin shapes the immune landscape and the gut microbiome can inform innovative interventions against immunosuppression and intestinal impairment, particularly in contexts such as cyclophosphamide-induced toxicity.

Alterations in tryptophan metabolism and de novo NAD+ biosynthesis within the microbiota-gut-brain axis in chronic intestinal inflammation

Background

Inflammatory bowel disease is an incurable and idiopathic disease characterized by recurrent gastrointestinal tract inflammation. Tryptophan metabolism in mammalian cells and some gut microbes comprise intricate chemical networks facilitated by catalytic enzymes that affect the downstream metabolic pathways of de novo nicotinamide adenine dinucleotide (NAD+) synthesis. It is hypothesized that a correlation exists between tryptophan de novo NAD+ synthesis and chronic intestinal inflammation.

Methods

Transcriptome analysis was performed using high-throughput sequencing of mRNA extracted from the distal colon and brain tissue of Winnie mice with spontaneous chronic colitis and C57BL/6 littermates. Metabolites were assessed using ultra-fast liquid chromatography to determine differences in concentrations of tryptophan metabolites. To evaluate the relative abundance of gut microbial genera involved in tryptophan and nicotinamide metabolism, we performed 16S rRNA gene amplicon sequencing of fecal samples from C57BL/6 and Winnie mice.

Results

Tryptophan and nicotinamide metabolism-associated gene expression was altered in distal colons and brains of Winnie mice with chronic intestinal inflammation. Changes in these metabolic pathways were reflected by increases in colon tryptophan metabolites and decreases in brain tryptophan metabolites in Winnie mice. Furthermore, dysbiosis of gut microbiota involved in tryptophan and nicotinamide metabolism was evident in fecal samples from Winnie mice. Our findings shed light on the physiological alterations in tryptophan metabolism, specifically, its diversion from the serotonergic pathway toward the kynurenine pathway and consequential effects on de novo NAD+ synthesis in chronic intestinal inflammation.

Conclusion

The results of this study reveal differential expression of tryptophan and nicotinamide metabolism-associated genes in the distal colon and brain in Winnie mice with chronic intestinal inflammation. These data provide evidence supporting the role of tryptophan metabolism and de novo NAD+ synthesis in IBD pathophysiology.

Bacillus subtilis improves antioxidant capacity and optimizes inflammatory state in broilers

OBJECTIVE

Bacillus subtilis, a kind of probiotic with broad-spectrum antibacterial function, was commonly used in livestock and poultry production. Recent research suggested that Bacillus subtilis may have antioxidant properties and improve immune response. This study aimed to verify the probiotic function of Bacillus subtilis in the production of broiler chickens.

METHODS

A total of 324 (1-day-old) Arbor Acres broilers were selected and randomly divided into three groups: basal diet group (Ctr Group), basal diet + antibiotic growth promoter group (Ctr + AGP) and basal diet + 0.5% Bacillus subtilis preparation group (Ctr + Bac). The experiment lasted for 42 days. Muscle, serum and liver samples were collected at 42 days for determination.

RESULTS

The results showed that Bacillus subtilis could decrease malondialdehyde content in the serum and liver (p<0.05) and increase superoxide dismutase 1 mRNA expression (p<0.01) and total superoxide dismutase (p<0.05) in the liver. In addition, compared with AGP supplementation, Bacillus subtilis supplementation increased interleukin-10 (IL-10) and decreased tumor necrosis factor-α and IL-1β level in the serum (p<0.05). At 45 minutes after slaughter Ctr + Bac presented a higher a* value of breast muscle than Ctr Group (p<0.05), while significant change in leg muscle was not identified. Moreover, there was no difference in weight, shear force, cooking loss and drip loss of breast and leg muscle between treatments.

CONCLUSION

Our results demonstrate that Bacillus subtilis in diet can enhance antioxidant capacity and optimize immune response of broilers.

Novel applications of Yinhua Miyanling tablets in ulcerative colitis treatment based on metabolomics and network pharmacology

BACKGROUND

Yinhua Miyanling tablets (YMT), comprising 10 Chinese medicinal compounds, is a proprietary Chinese medicine used in the clinical treatment of urinary tract infections. Medicinal compounds, extracts, or certain monomeric components in YMT all show good effect on ulcerative colitis (UC). However, no evidence supporting YMT as a whole prescription for UC treatment is available.

PURPOSE

To evaluate the anti-UC activity of YMT and elucidate the underlying mechanisms. The objective of the study was to provide evidence for the add-on development of YMT to treat UC.

METHODS

First, YMT's protective effect on the intestinal barrier was evaluated using a lipopolysaccharide (LPS)-induced Caco-2 intestinal injury model. Second, the UC mouse model was established using dextran sodium sulfate (DSS) to determine YMT's influence on symptoms, inflammatory factors, intestinal barrier, and histopathological changes in the colon. Third, an integrated method combining metabolomics and network pharmacology was employed to screen core targets and key metabolic pathways with crucial roles in YMT's therapeutic effect on UC. Molecular docking was employed to identify the key targets with high affinity. Finally, western blotting was performed to validate the mechanism of YMT action against UC.

RESULTS

YMT enhanced the transepithelial electrical resistance value and improved the expression of proteins of the tight junctions dose-dependently in LPS-induced Caco-2 cells. UC mice treated with YMT exhibited alleviated pathological lesions of the colon tissue in the in vivo pharmacodynamic experiments. The colonic lengths tended to be normal, and the levels of inflammatory factors (TNF-α, IL-6, and iNOS) along with those of the core enzymes (MPO, MDA, and SOD) improved. YMT effectively ameliorated DSS-induced colonic mucosal injury; pathological changes along with ultrastructure damage were significantly alleviated (evidenced by a relatively intact colon tissue, recovery of epithelial damage, repaired gland, reduced infiltration of inflammatory cells and epithelial cells arranged closely with dense microvilli). Seven key targets (IL-6, TNF-α, MPO, COX-2, HK2, TPH, and CYP1A2) and four key metabolic pathways (arachidonic acid metabolism, linoleate metabolism, glycolysis, and gluconeogenesis and tyrosine biosynthesis) were identified to play vital roles in the treatment on UC using YMT.

CONCLUSIONS

YMT exerts beneficial therapeutic effects on UC by regulating multiple endogenous metabolites, targets, and metabolic pathways, suggestive of its potential novel application in UC treatment.

Wheat peptide alleviates DSS-induced colitis by activating the Keap1-Nrf2 signaling pathway and maintaining the integrity of the gut barrier

Inflammatory bowel disease (IBD) is difficult to cure, and formulating a dietary plan is an effective means to prevent and treat this disease. Wheat peptide contains a variety of bioactive peptides with anti-inflammatory and antioxidant functions. The results of this study showed that preventive supplementation with wheat peptide (WP) can significantly alleviate the symptoms of dextran sulfate sodium (DSS)-induced colitis in mice. WP can increase body weight, alleviate colon shortening, and reduce disease activity index (DAI) scores. In addition, WP improved intestinal microbial disorders in mice with colitis. Based on LC-MS, a total of 313 peptides were identified in WP, 4 of which were predicted to be bioactive peptides. The regulatory effects of WP and four bioactive peptides on the Keap1-Nrf2 signaling pathway were verified in Caco-2 cells. In conclusion, this study demonstrated that WP alleviates DSS-induced colitis by helping maintain gut barrier integrity and targeting the Keap1-Nrf2 axis; these results provided a rationale for adding WP to dietary strategies to prevent IBD.

Association of gut microbiota with cerebral cortical thickness: A Mendelian randomization study

BACKGROUND

The causal relationship between gut microbiota and cerebral cortex development remains unclear. We aimed to scrutinize the plausible causal impact of gut microbiota on cortical thickness via Mendelian randomization (MR) study.

METHODS

Genome-wide association study (GWAS) data for 196 gut microbiota phenotypes (N = 18,340) were obtained as exposures, and GWAS data for cortical thickness-related traits (N = 51,665) were selected as outcomes. Inverse variance weighted was used as the main estimate method. A series of sensitivity analyses was used to test the robustness of the estimates including Cochran's Q test, MR-Egger intercept analysis, Steiger filtering, scatter plot funnel plot and leave-one-out analysis.

RESULTS

Genetic prediction of high Bacillales (β = 0.005, P = 0.032) and Lactobacillales (β = 0.010, P = 0.012) abundance was associated with a potential increase in global cortical thickness. For specific functional brain subdivisions, genetically predicted order Lactobacillales would potentially increase the thickness of the fusiform (β = 0.014, P = 0.016) and supramarginal (β = 0.017, P = 0.003). Meanwhile, order Bacillales would increase the thickness of fusiform (β = 0.007, P = 0.039), insula (β = 0.011, P = 0.003), rostralanteriorcingulate (β = 0.014, P = 0.002) and supramarginal (β = 0.006, P = 0.043). No significant estimates of heterogeneity or pleiotropy were found.

CONCLUSIONS

Through MR studies, we discovered genetic prediction of the Lactobacillales and Bacillales orders potentially linked to cortical thickness, affirming gut microbiota may enhance brain structure. Genetically predicted supramarginal and fusiform may be potential targets.

Gut microbiota-derived 5-hydroxyindoleacetic acid from pumpkin polysaccharides supplementation alleviates colitis via MAPKs-PPARγ/NF-κB inhibition

Polysaccharides from Pumpkin (Cucurbita moschata Duchesne) (PPs) have many pharmacological activities, including anti-oxidant, immune, and intestinal microbiota regulation. These activities have provided some reminders of its potential therapeutic effect on ulcerative colitis (UC), but this has not yet been confirmed. This study preliminarily confirmed its significant anti-UC activity superior to Salicylazosulfapyridine. The average molecular weight of PPs was 3.10 × 105 Da, and PPs mainly comprised Mannose, Rhamnose, Galacturonic acid, Galactosamine, Glucose, and Xylose with molar ratios of 1.58:3.51:34.54:1.00:3.25:3.02. PPs (50, 100 mg/kg) could significantly resist dextran sodium sulfate induced UC on C57BL/6 mice by improving gut microbiota dysbiosis, such as the changes of relative abundance of Bacteroides, Culturomica, Mucispirillum, Escherichia-Shigella, Alistipes and Helicobacter. PPs also reverse the abnormal inflammatory reaction, including abnormal level changes of TNF-α, IFN-γ, IL-1β, IL-4, IL-6, IL-10, and IL-18. Metabolomic profiling showed that PPs supplementation resulted in the participation of PPAR and MAPK pathways, as well as the increase of 5-hydroxyindole acetic acid (5-HIAA) level. 5-HIAA also exhibited individual and synergistic anti-UC activities in vivo. Furthermore, combination of PPs and 5-HIAA could also elevate the levels of PPARγ in nuclear and inhibit MAPK/NF-ĸB pathway in the colon. This study revealed that PPs and endogenous metabolite 5-HIAA might be developed to treat UC.

A leaky gut dysregulates gene networks in the brain associated with immune activation, oxidative stress, and myelination in a mouse model of colitis

The gut and brain are increasingly linked in human disease, with neuropsychiatric conditions classically attributed to the brain showing an involvement of the intestine and inflammatory bowel diseases (IBDs) displaying an ever-expanding list of neurological comorbidities. To identify molecular systems that underpin this gut-brain connection and thus discover therapeutic targets, experimental models of gut dysfunction must be evaluated for brain effects. In the present study, we examine disturbances along the gut-brain axis in a widely used murine model of colitis, the dextran sodium sulfate (DSS) model, using high-throughput transcriptomics and an unbiased network analysis strategy coupled with standard biochemical outcome measures to achieve a comprehensive approach to identify key disease processes in both colon and brain. We examine the reproducibility of colitis induction with this model and its resulting genetic programs during different phases of disease, finding that DSS-induced colitis is largely reproducible with a few site-specific molecular features. We focus on the circulating immune system as the intermediary between the gut and brain, which exhibits an activation of pro-inflammatory innate immunity during colitis. Our unbiased transcriptomics analysis provides supporting evidence for immune activation in the brain during colitis, suggests that myelination may be a process vulnerable to increased intestinal permeability, and identifies a possible role for oxidative stress and brain oxygenation. Overall, we provide a comprehensive evaluation of multiple systems in a prevalent experimental model of intestinal permeability, which will inform future studies using this model and others, assist in the identification of druggable targets in the gut-brain axis, and contribute to our understanding of the concomitance of intestinal and neuropsychiatric dysfunction.

The Impact of Intestinal Microbiota and Toll-like Receptor 2 Signaling on α-Synuclein Pathology in Nontransgenic Mice Injected with α-Synuclein Preformed Fibrils

Intestinal microbiota and Toll-like receptor 2 (TLR2), which can bind lipoteichoic acid produced by microbiota, might contribute to the pathogenesis of Parkinson's disease (PD), which is characterized by α-synuclein accumulation. Although the contribution of intestinal microbiota and TLR2 to PD pathology was validated in genetic PD models, evidence suggests that the effects of TLR2 signaling on proteinopathy might depend on the presence of a genetic etiology. We examined the impact of intestinal microbiota and TLR2 signaling on α-synuclein pathology in a nontransgenic mouse model of sporadic PD. While an α-synuclein preformed fibrils injection successfully reproduced PD pathology by inducing accumulation of α-synuclein aggregates, microglial activation and increased TLR2 expression in the brains of nontransgenic mice, antibiotic-induced reduction in the density of intestinal microbiota and TLR2 knockout had small impact on these changes. These findings, which are in contrast to those reported in transgenic mice harboring transgene encoding α-synuclein, indicate that the contribution of intestinal microbiota and TLR2 signaling to α-synuclein pathogenesis might be influenced by the presence of a genetic etiology. Additionally, these findings suggest that integrating insights from this experimental model and genetic models would further advance our understanding of the molecular mechanisms underlying sporadic PD.

Lipopeptides from an isolate of Bacillus subtilis complex have inhibitory and antibiofilm effects on Fusarium solani

Bacillus subtilis species complex is known as lipopeptide-producer with biotechnological potential for pharmaceutical developments. This study aimed to identify lipopeptides from a bacterial isolate and evaluate their antifungal effects. Here, we isolated and identified a lipopeptide-producing bacterium as a species of Bacillus subtilis complex (strain UL-1). Twenty lipopeptides (six iturins, six fengycins, and eight surfactins) were identified in the crude extract (CE) and fractions (F1, F2, F3, and F4), and the highest content of total lipopeptides was observed in CE and F2. The chemical quantification data corroborate with the hemolytic and antifungal activities that CE and F2 were the most hemolytic and inhibited the fungal growth at lower concentrations against Fusarium spp. In addition, they caused morphological changes such as shortening and/or atypical branching of hyphae and induction of chlamydospore-like structure formation, especially in Fusarium solani. CE was the most effective in inhibiting the biofilm formation and in disrupting the mature biofilm of F. solani reducing the total biomass and the metabolic activity at concentrations ≥ 2 µg/mL. Moreover, CE significantly inhibited the adherence of F. solani conidia on contact lenses and nails as well as disrupted the pre-formed biofilms on nails. CE at 100 mg/kg was nontoxic on Galleria mellonella larvae, and it reduced the fungal burden in larvae previously infected by F. solani. Taken together, the lipopeptides obtained from strain UL-1 demonstrated a potent anti-Fusarium effect inducing morphological alterations and antibiofilm activities. Our data open further studies for the biotechnological application of these lipopeptides as potential antifungal agents. KEY POINTS: • Lipopeptides inhibit Fusarium growth and induce chlamydospore-like structures. • Lipopeptides hamper the adherence of conidia and biofilms of Fusarium solani. • Iturins, fengycins, and surfactins were associated with antifungal effects.

A leaky gut dysregulates gene networks in the brain associated with immune activation, oxidative stress, and myelination in a mouse model of colitis

The gut and brain are increasingly linked in human disease, with neuropsychiatric conditions classically attributed to the brain showing an involvement of the intestine and inflammatory bowel diseases (IBDs) displaying an ever-expanding list of neurological comorbidities. To identify molecular systems that underpin this gut-brain connection and thus discover therapeutic targets, experimental models of gut dysfunction must be evaluated for brain effects. In the present study, we examine disturbances along the gut-brain axis in a widely used murine model of colitis, the dextran sodium sulfate (DSS) model, using high-throughput transcriptomics and an unbiased network analysis strategy coupled with standard biochemical outcome measures to achieve a comprehensive approach to identify key disease processes in both colon and brain. We examine the reproducibility of colitis induction with this model and its resulting genetic programs during different phases of disease, finding that DSS-induced colitis is largely reproducible with a few site-specific molecular features. We focus on the circulating immune system as the intermediary between the gut and brain, which exhibits an activation of pro-inflammatory innate immunity during colitis. Our unbiased transcriptomics analysis provides supporting evidence for immune activation in the brain during colitis, suggests that myelination may be a process vulnerable to increased intestinal permeability, and identifies a possible role for oxidative stress and brain oxygenation. Overall, we provide a comprehensive evaluation of multiple systems in a prevalent experimental model of intestinal permeability, which will inform future studies using this model and others, assist in the identification of druggable targets in the gut-brain axis, and contribute to our understanding of the concomitance of intestinal and neuropsychiatric dysfunction.

Oral intake of titanium dioxide nanoparticles affect the course and prognosis of ulcerative colitis in mice: involvement of the ROS-TXNIP-NLRP3 inflammasome pathway

BACKGROUND

Titanium dioxide (TiO2), no matter in nanoscale or micron sizes, has been widely used in food industry as additives for decades. Given the potential impact of TiO2 on the gastrointestinal epithelial and parenchymal cells, including goblet cells, the public consumers may suffer the risk of diseases caused by its widespread dissemination in food products. We therefore set out to investigate the impact of TiO2 NPs on the course and prognosis of ulcerative colitis by oral gavaging TiO2 NPs at the doses levels of 0, 30, 100, and 300 mg/kg during the induction (7 days, from day 1 to day 7) and recovery (10 days, from day 8 to day 17) phases of colitis in mice.

RESULTS

The ulcerative colitis (UC) disease model was established by administrating of 2.5% dextran sulfate sodium (DSS) solution. Our results show that TiO2 NPs significantly enhanced the severity of DSS-induced colitis, decreased the body weight, increased the disease activity index (DAI) and colonic mucosa damage index (CMDI) scores, shortened the colonic length, increased the inflammatory infiltration in the colon. The most significant changes occurred in the low dose (30 mg/kg) group of TiO2 NPs exposure during the development phase of UC and the high dose (300 mg/kg) group of TiO2 NPs during UC self-healing phase. Increased reactive oxygen species (ROS) level and upregulation of anti-oxidant enzymes including total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-PX) and catalase (CAT), demonstrate that the TiO2 NP exposure has triggered oxidative stress in mice. Moreover, the upregulation of caspase-1 mRNA and increased expression of thioredoxin interacting protein (TXNIP) further demonstrate the involvement of the ROS-TXNIP-NLR family pyrin domain containing 3 (NLRP3) inflammasome pathway in aggravating the development of UC.

CONCLUSION

Oral intake of TiO2 NPs could affect the course of acute colitis in exacerbating the development of UC, prolonging the UC course and inhibiting UC recovery.