Bacterial resistance leads to severe public health and safety issues worldwide. Alternatives to antibiotics are currently needed. A promising lasso peptide, microcin J25 (MccJ25), is considered to be the best potential substitute for antibiotics to treat pathogen infection, including enterotoxigenic Escherichia coli (ETEC). This study evaluated the efficacy of MccJ25 in the prevention of ETEC infection. Forty-five female BALB/c mice of clean grade (aged seven weeks, approximately 16.15 g) were randomly divided into three experimental groups as follows: (i) control group (uninfected); (ii) ETEC infection group; (iii) MccJ25 + ETEC group. Fifteen mice per group in five cages, three mice/cage. MccJ25 conferred effective protection against ETEC-induced body weight loss, decrease in rectal temperature and increase in diarrhea scores in mice. Moreover, in ETEC-challenged mice model, MccJ25 significantly improved intestinal morphology, decreased intestinal histopathological scores and attenuated intestinal inflammation by decreasing proinflammatory cytokines and intestinal permeability, including reducing serum diamine oxidase and D-lactate levels. MccJ25 enhanced epithelial barrier function by increasing occludin expression in the colon and claudin-1 expression in the jejunum, ultimately improving intestinal health of host. MccJ25 was further found to alleviate gut inflammatory responses by decreasing inflammatory cytokine production and expression via the activation of the mitogen-activated protein kinase and nuclear factor κB signaling pathways. Taken together, the results indicated that MccJ25 protects against ETEC-induced intestinal injury and intestinal inflammatory responses, suggesting the potential application of MccJ25 as an excellent antimicrobial or anti-inflammation agent against pathogen infections.

Background: Ulcerative colitis is an emerging global health concern that poses a significant threat to human health and can progress to colorectal cancer if not diagnosed and treated promptly. Currently, the biomarkers used clinically for diagnosis and dynamic severity monitoring lack disease specificity.Methods: Mouse models induced with 2%, 2.5%, and 3% DSS were utilized to simulate human UC with varying severities of inflammation. Transcriptome sequencing technology was employed to identify differentially expressed genes (DEGs) between the control group and each treatment group. Functional enrichment analysis of the KEGG database was performed for shared DEGs among the three treatment groups. DEGs that were significantly and strongly correlated with DSS concentrations were identified using Spearman correlation analysis. Human homologous genes of the interested DEGs were searched in the HomoloGene database, and their regulation patterns in UC patients were validated using the GSE224758 dataset. These genes were then submitted to the DisGeNET database to identify their known associations with human diseases. Online tools, including SignalP 6.0 and DeepTMHMM 1.0, were used to predict signal peptides and transmembrane helices in the amino acid sequences of human genes homologous to the DEGs of interest.Results: A total of 1,230, 995, and 2,214 DEGs were identified in the 2%, 2.5%, and 3% DSS-induced groups, respectively, with 668 DEGs common across all three groups. These shared DEGs were primarily associated with signaling transport, pathogenesis, and immune response. Through extensive screening, LGI2 and PRSS22 were identified as potentially novel biomarkers with higher specificity and ease of detection for the early diagnosis and dynamic severity monitoring of human UC, respectively.Conclusion: We have identified two potentially novel biomarkers, LGI2 and PRSS22, which are easy of detection and more specific for human UC. These findings provide new insights into the accurate diagnosis and dynamic monitoring of this persistent disease.

With the prohibition of antibiotics in animal feed, the livestock industry faces significant challenges, including increased morbidity and mortality rates and reduced farming efficiency. Developing green, natural, and safe antibiotic alternatives has become a research hotspot. This study evaluated the effects of octapeptin as a feed additive on growth performance, diarrhea incidence, serum biochemistry, serum immune factors, and gut microbiota of weaned piglets. Seventy-two weaned piglets were randomly assigned to three groups based on body weight and sex, with each group receiving different dietary treatments: a negative control group (CON, basal diet), a positive control group (MC, basal diet + 5 mg/kg Microcin C7), and an octapeptin supplement group (OP, basal diet + 40 mg/kg octapeptin). After 28 days of feeding experimental diets, the results demonstrated that supplementing the diet of weaned piglets with octapeptin significantly improved the feed conversion ratio compared to the control group (p < 0.05) over the entire experimental period. Furthermore, a reduction in diarrhea incidence was observed during the late nursery period (14–28 d), resulting in an overall improvement in diarrhea compared to the other two groups (p < 0.01). Serum biochemical analysis results revealed a trend towards decreased alanine aminotransferase level in the octapeptin group, with no significant differences in other indicators, suggesting potential improvements in liver function without causing liver damage. In addition, compared to the control group, octapeptin enhanced mucosal immunity by decreasing TNF-α level (p < 0.05). Fecal microbiota analysis results showed a significant increase in beneficial bacteria such as Collinsella and Olsenella in the octapeptin group compared to the other two groups (p < 0.05), indicating a positive impact on gut health. These findings supported the potential of octapeptin as an alternative to antibiotic growth promoters in weaned piglets’ diets.