Dietary supplementation with low-dose xylooligosaccharide promotes the anti-Salmonella activity of probiotic Lactiplantibacillus plantarum ZS2058 in a murine model

Diet xylo-oligosaccharide supplementation improves growth performance, immune function, and intestinal health of broilers

The effects of xylo-oligosaccharides (XOS) on broiler growth performance, immune function, and intestinal health were investigated. A total of 540 one-d-old Arbor Acres Plus broilers were randomly divided into 5 groups with 6 replicates per group and 18 chickens per replicate. Broilers in the control (CON) group received a corn-soybean meal based basal diet, those in the antibiotics (ANT) group received the basal diet plus 500 mg/kg oxytetracycline, and those in XOS groups received the basal diet plus 150, 300, or 450 mg/kg XOS. Compared with CON, the body weight at 42 d and average daily gain from 1 to 42 d were significantly increased in the 150, 450 mg/kg XOS-added and ANT groups (P = 0.018), and the relative expression of claudin-1 and ZO-1 mRNA in the ileum was significantly higher in the 300 and 450 mg/kg XOS-added groups (P < 0.001). The feed conversion ratios (P < 0.001) and abdominal fat rates (P = 0.012) of broilers from 1 to 42 d of age were significantly lower in all XOS-added groups than in the control group. Splenic index (P = 0.036) and bursa of Fabricius index (P = 0.009) were significantly better in the ANT group and each XOS-added group than in the control group. Compared to CON and ANT, serum IgA (P = 0.007) and IgG (P = 0.002) levels were significantly higher in the 300 mg/kg XOS-added group, and the relative abundance of short-chain fatty acid-producing genera (Alistipes) was also significantly higher (P < 0.001). Meanwhile, ileal villus height (P < 0.001) and ratio of villus height to crypt depth (V:C) (P = 0.001) were significantly increased in XOS-added broilers. In analysis of relationships between cecal microbes and the physical barrier of the gut, [Ruminococcus]_torques_group was positively correlated with mRNA expression of ileal ZO-1 and claudin-1 (P < 0.05), and Bacteroides was positively correlated with increased ileal villus height and V:C (P < 0.05). Overall, XOS addition to broiler diets improved growth performance, promoted intestinal health by enhancing intestinal barrier function and regulating cecal microbiota diversity, and had positive effects on immunity.

SUMOylation inhibitors activate anti-tumor immunity by reshaping the immune microenvironment in a preclinical model of hepatocellular carcinoma

PURPOSE

High levels of heterogeneity and immunosuppression characterize the HCC immune microenvironment (TME). Unfortunately, the majority of hepatocellular carcinoma (HCC) patients do not benefit from immune checkpoint inhibitors (ICIs) therapy. New small molecule therapies for the treatment of HCC are the goal of our research.

METHODS

SUMOylation inhibitors (TAK-981 and ML-792) were evaluated for the treatment of preclinical mouse HCC models (including subcutaneous and orthotopic HCC models). We profile immune cell subsets from tumor samples after SUMOylation inhibitors treatment using single-cell RNA sequencing (scRNA-seq), mass cytometry (CyTOF), flow cytometry, and multiple immunofluorescences (mIF).

RESULTS

We discover that SUMOylation is higher in HCC patient samples compared to normal liver tissue. TAK-981 and ML-792 decrease SUMOylation at nanomolar levels in HCC cells and also successfully reduced the tumor burden. Analysis combining scRNA-seq and CyTOF demonstrate that treatment with SUMOylation inhibitors reduces the exhausted CD8+T (Tex) cells while enhancing the cytotoxic NK cells, M1 macrophages and cytotoxic T lymphocytes (CTL) in preclinical mouse HCC model. Furthermore, SUMOylation inhibitors have the potential to activate innate immune signals from CD8+T, NK and macrophages while promoting TNFα and IL-17 secretion. Most notably, SUMOylation inhibitors can directly alter the TME by adjusting the abundance of intestinal microbiota, thereby restoring anti-tumor immunity in HCC models.

CONCLUSIONS

This preclinical study suggests that SUMO signaling inhibitors may be beneficial for the treatment of HCC.

Effective reduction of Salmonella Enteritidis in broiler chickens using the UPWr_S134 phage cocktail

Salmonella is a poultry-associated pathogen that is considered one of the most important zoonotic bacterial agents of contaminated food of animal origin including poultry products. Many efforts are taken to eliminate it from the food chain, and phages are one of the most promising tools to control Salmonella in poultry production. We investigated the usefulness of the UPWr_S134 phage cocktail in reducing Salmonella in broiler chickens. For this purpose, we analyzed the survivability of phages in the harsh environment encountered in the chicken gastrointestinal tract, which has low pH, high temperatures, and digestive activity. Phages in the cocktail UPWr_S134 showed the ability to remain active after storage at temperatures ranging from 4 to 42°C, reflecting temperatures of storage conditions, broiler handling, and the chicken body, and exhibited robust pH stability. We found that although simulated gastric fluids (SGF) caused phage inactivation, the addition of feed to gastric juice allows maintenance of UPWr_S134 phage cocktail activity. Further, we analyzed UPWr_S134 phage cocktail anti-Salmonella activity in live animals such as mice and broilers. In an acute infection model in mice, the application of doses of 10⁷ and 10¹⁴ PFU/ml UPWr_S134 phage cocktail resulted in delaying symptoms of intrinsic infection in all analyzed treatment schedules. In Salmonella-infected chickens orally treated with the UPWr_S134 phage cocktail the number of pathogens in internal organs in comparison to untreated birds was significantly lower. Therefore we concluded that the UPWr_S134 phage cocktail could be an effective tool against this pathogen in the poultry industry.

Characterization and evaluation of anti-Salmonella enteritidis activity of indigenous probiotic lactobacilli in mice

Lactobacilli (n = 24), isolated from human infants and yogurt, showed variable in vitro activity against Salmonella enteritidis (8.0 ± 1.0 to 16.6 ± 0.5 mm) and other gut pathogens (9.0 ± 1.0 to 15.3 ± 0.5 mm), as determined by a well diffusion assay. The isolates were identified as Limosilactobacillus fermentum (FY1, FY3, FY4, IL2, and IL5), Lactobacillus delbrueckii (FY6 and FY7), Lactobacillus sp. (IL7), and Lactobacillus gasseri (IL12). All isolates showed variable in vitro tolerance to acidic pH for 3 h and visible growth at pH 4 and in the presence of 0.3% ox-bile. The antibiotic susceptibility profile of Lactobacillus isolates indicated resistance against vancomycin, ciprofloxacin, streptomycin, and lincomycin. Isolates had variable auto-aggregation and showed variable capabilities to co-aggregate with S. enteritidis. Based on all tested parameters, L. fermentum IL2, L. fermentum IL5, and L. gasseri IL12 were selected for co-culture experiments, followed by in vivo evaluation in Balb/c mice. All the selected isolates resulted in a 100% reduction in S. enteritidis in broth. Lactobacillus isolates efficiently colonized mouse guts and inhibited S. enteritidis colonization. Overall, there was ≥99.06% and ≤4.32 Mean log₁₀ reduction in Salmonella counts in mice feces within 7 days. The study, thus, provided characterized lactobacilli that could be considered as potential ingredients for probiotic formulations intended to prevent S. enteritidis infection in humans.

Bacteriocinogenic probiotic bacteria isolated from an aquatic environment inhibit the growth of food and fish pathogens

The conditions of aquatic environments have a great influence on the microbiota of several animals, many of which are a potential source of microorganisms of biotechnological interest. In this study, bacterial strains isolated from aquatic environments were bioprospected to determine their probiotic profile and antimicrobial effect against fish and food pathogens. Two isolates, identified via 16S rRNA sequencing as Lactococcus lactis (L1 and L2) and one as Enterococcus faecium 135 (EF), produced a bacteriocin-like antimicrobial substance (BLIS), active against Listeria monocytogenes, Salmonella Choleraesuis and Salmonella Typhimurium. Antimicrobial activity of BLIS was reduced when exposed to high temperatures and proteolytic enzymes (trypsin, pepsin, papain and pancreatin). All strains were sensitive to 7 types of antibiotics (vancomycin, clindamycin, streptomycin, gentamicin, chloramphenicol, rifampicin and ampicillin), exhibited a high rate of adherence to Caco-2 cells and expressed no hemolysin and gelatinase virulence factors. EF showed some resistance at pH 2.5 and 3.0, and L2/EF showed higher resistance to the action of bile salts. Finally, the presence of bacteriocin genes encoding for proteins, including Nisin (L1 and L2), Enterocin A, B, P, and Mundticin KS (EF) was detected. The molecular and physiological evidence suggests that the bacterial isolates in this study could be used as natural antimicrobial agents and may be considered safe for probiotic application.