Bacteriocins: Curial guardians of gastrointestinal tract.

The human gastrointestinal (GI) tract microbiome secretes various metabolites that play pivotal roles in maintaining host physiological balance and influencing disease progression. Among these metabolites, bacteriocins-small, heat-stable peptides synthesized by ribosomes-are notably prevalent in the GI region. Their multifaceted benefits have garnered significant interest in the scientific community. This review comprehensively explores the methods for mining bacteriocins (traditional separation and purification, bioinformatics, and artificial intelligence), their effects on the stomach and intestines, and their complex bioactive mechanisms. These mechanisms include flora regulation, biological barrier restoration, and intervention in epithelial cell pathways. By detailing each well-documented bacteriocin, we reveal the diverse ways in which bacteriocins interact with the GI environment. Moreover, the future research direction is prospected. By further studying the function and interaction of intestinal bacteriocins, we can discover new pharmacological targets and develop drugs targeting intestinal bacteriocins to regulate and improve human health. It provides innovative ideas and infinite possibilities for further exploration, development, and utilization of bacteriocins. The inevitable fact is that the continuously exploration of bacteriocins is sure to bring the promising future for demic GI health understanding and interference strategy.

A Class IIb Bacteriocin Plantaricin NC8 Modulates Gut Microbiota of Different Enterotypes in vitro.

The gut microbiota is engaged in multiple interactions affecting host health. Bacteriocins showed the ability of impeding the growth of intestinal pathogenic bacteria and modulating gut microbiota in animals. Few studies have also discovered their regulation on human intestinal flora using an in vitro simulated system. However, little is known about their effect on gut microbiota of different enterotypes of human. This work evaluated the modification of the gut microbiota of two enterotypes (ET B and ET P) by the class IIb bacteriocin plantaricin NC8 (PLNC8) by using an in vitro fermentation model of the intestine. Gas chromatography results revealed that PLNC8 had no influence on the gut microbiota's production of short-chain fatty acids in the subjects' samples. PLNC8 lowered the Shannon index of ET B' gut microbiota and the Simpson index of ET P' gut microbiota, according to 16S rDNA sequencing. In ET B, PLNC8 enhanced the abundance of Bacteroides, Bifidobacterium, Megamonas, Escherichia-Shigella, Parabacteroides, and Lactobacillus while decreasing the abundance of Streptococcus. Prevotella_9, Bifidobacterium, Escherichia-Shigella, Mitsuokella, and Collinsella were found more abundant in ET P. The current study adds to our understanding of the impact of PLNC8 on the human gut microbiota and lays the groundwork for future research into PLNC8's effects on human intestinal disease.

A protein-fragment complementation assay reveals that celastrol and gambogic acid suppress ERα mutants in breast cancer.

Somatic gain-of-function mutations within estrogen receptor alpha (ERα) are highly associated with hormone therapy resistance in breast cancer. However, current understanding of abnormal activity of ERα mutants and their relevant targeted intervention is still very limited. Herein, we developed a new, real-time, and reliably Gaussia luciferase-based protein-fragment complementation assay (GLPCA) for evaluating ERα mutants activities. We found that, compared with ER WT, ERα mutants (Y537S/N and D538G) exhibit high ligand-independent activity, suggesting the gain-of-function phenotype of these ERα mutants. Notably, Y537S, the most common ERα mutant type, has the highest intrinsic activation. We then collected and screened a natural product library for potential ERα antagonists via GLPCA and identified celastrol and gambogic acid as new antagonists of the ERα Y537S mutant. Moreover, interactions between these two compounds and the ERα Y537S mutant were confirmed by molecular docking and cellular thermal shift assay. Importantly, we further demonstrated that celastrol and gambogic acid exhibit synergistic antiproliferative and pro-apoptotic effects when combined with an approved CDK4/6 inhibitor abemaciclib in breast cancer cells expressing ERα Y537S. In summary, GLPCA provides a powerful platform for exploring innovative functional biology and drug discovery of antagonists targeting ERα mutants.

Moracin C, A Phenolic Compound Isolated from Artocarpus heterophyllus, Suppresses Lipopolysaccharide-Activated Inflammatory Responses in Murine Raw264.7 Macrophages.

Artocarpus heterophyllus, a popular tropical fruit commonly known as the jackfruit tree, is normally planted in subtropical or tropical areas. Since a variety of phytochemicals isolated from A. heterophyllus have been found to possess potently anti-inflammatory, antiviral and antimalarial activities, researchers have devoted much interest to its potential pharmaceutical value. However, the exact mechanism underlying its anti-inflammatory activity is not well characterized. In this study, seven natural products isolated from A. heterophyllus, including 25-Hydroxycycloart-23-en-3-one (HY), Artocarpin (AR), Dadahol A (DA), Morachalcone A (MA), Artoheterophyllin B (AB), Cycloheterophyllin (CY) and Moracin C (MC) were collected. Lipopolysaccharide (LPS)-stimulated inflammatory response in RAW264.7 macrophages were used in this study. Among these compounds, MC significantly inhibited LPS-activated reactive oxygen species (ROS) and nitric oxide (NO) release without marked cytotoxicity. Furthermore, MC effectively reduced LPS stimulated up-regulation of mRNA and protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and serval pro-inflammatory cytokines (interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α)). Mechanistic studies revealed that the anti-inflammatory effect of MC was associated with the activation of the mitogen activated protein kinases (MAPKs) (including p38, ERK and JNK) and nuclear factor-κB (NF-κB) pathways, especially reducing the nuclear translocation of NF-κB p65 subunit as revealed by nuclear separation experiment and confocal microscopy.