Lipopolysaccharide (LPS) extracted from Bacteroides vulgatus effectively prevents LPS extracted from Escherichia coli from inducing epithelial‑mesenchymal transition

Lipopolysaccharide induces retention of E-cadherin in the endoplasmic reticulum and promotes hybrid epithelial-to-mesenchymal transition of human embryonic stem cells-derived expandable lung epithelial cells

BACKGROUND

Lipopolysaccharide (LPS)-induced inflammation of lung tissues triggers irreversible alterations in the lung parenchyma, leading to fibrosis and pulmonary dysfunction. While the molecular and cellular responses of immune and connective tissue cells in the lungs are well characterized, the specific epithelial response remains unclear due to the lack of representative cell models. Recently, we introduced human embryonic stem cell-derived expandable lung epithelial (ELEP) cells as a novel model for studying lung injury and regeneration.

METHODS

ELEPs were derived from the CCTL 14 human embryonic stem cell line through activin A-mediated endoderm specification, followed by further induction toward pulmonary epithelium using FGF2 and EGF. ELEPs exhibit a high proliferation rate and express key structural and molecular markers of alveolar progenitors, such as NKX2-1. The effects of Escherichia coli LPS serotype O55:B5 on the phenotype and molecular signaling of ELEPs were analyzed using viability and migration assays, mRNA and protein levels were determined by qRT-PCR, western blotting, and immunofluorescent microscopy.

RESULTS

We demonstrated that purified LPS induces features of a hybrid epithelial-to-mesenchymal transition in pluripotent stem cell-derived ELEPs, triggers the unfolded protein response, and upregulates intracellular β-catenin level through retention of E-cadherin within the endoplasmic reticulum.

CONCLUSIONS

Human embryonic stem cell-derived ELEPs provide a biologically relevant, non-cancerous lung cell model to investigate molecular responses to inflammatory stimuli and address epithelial plasticity. This approach offers novel insights into the fine molecular processes underlying lung injury and repair.

The human gut Bacteroides eggerthii expresses a new galactofuranose-containing lipooligosaccharide with weak immunostimulatory properties

Lipopolysaccharides (LPS) decorating the cell surface of Gram-negative bacteria exhibit nuanced functionalities linked to their precise structural composition. However, despite their critical role in health and disease, information on the structure and function of LPS from members of the human gut microbiota is still limited. Here, we deciphered the complete structure of the LPS isolated from the human gut bacterium Bacteroides eggerthii 1_2_48FAA. We showed that B. eggerthii 1_2_48FAA produces an R-type LPS (or lipooligosaccharide, LOS) composed of a heterogeneous mixture of tetra- and penta-acylated lipid A species with different degree of phosphorylation, and a compact galactofuranose-containing core oligosaccharide. Using in vitro human cell lines, we showed that B. eggerthii 1_2_48FAA LOS acts as a weak activator of TLR4-mediated signaling. Moreover, we observed that expression of maturation markers CD40, CD80 and CD86 on monocytes-derived dendritic cells upon B. eggerthii 1_2_48FAA LOS exposure was significantly lower compared to pro-inflammatory Escherichia coli LPS. Taken together, these data provide new structural and biological insights into LPS from gut bacteria, underscoring the importance of structural features in modulating host immunity.

Isolation, identification and characteristics of Bibersteinia trehalosi from goat

A conditionally pathogenic bacterium called Bibersteinia trehalosi inhabits the upper respiratory tract of ruminants and is becoming a significant cause of pneumonia, especially in goats. In this study, we identified a gram-negative bacteria strain isolated from dead goat's lungs, which was named M01. By integrating the outcomes of its morphological and biochemical characterization with the investigation of the 16S rRNA gene sequence analysis, the isolate was identified as B. trehalosi. Based on antibiotic susceptibility tests, the isolate was shown to be resistant to β-lactams, tetracyclines, and amphenicols. Its genome was discovered to comprise 2115 encoded genes and a circular chromosome measuring 2,345,568 bp using whole genome sequencing. Annotation of the VFBD database revealed that isolate M01 had four virulence genes encoding three virulence factors. The CARD database revealed that its genome has two antibiotic-resistance genes. Based on pathogenicity testing, isolate M01 was highly pathogenic to mice, primarily causing pneumonia, with an LD50 of 1.31 × 107 CFU/ml. Moreover, histopathology showed loss of alveolar structure and infiltration of lung inflammatory cells. Hence, the current study could provide sufficient information for prevention and control strategies for future epidemics of B. trehalosi in goat species.

Elucidation of antioxidant activities of intracellular and extracellular polysaccharides from Cordyceps militaris in vitro and their protective effects on ulcerative colitis in vivo

In this study, we extracted the polysaccharides from C. militaris fruiting bodies (CFIPs), mycelial intracellular polysaccharides (CMIPs), and fermentation broth extracellular polysaccharides (CFEPs) to investigate their physicochemical properties, antioxidant capacities, and effects on oxazolone-induced zebrafish ulcerative colitis (UC). Our results revealed differences in monosaccharide composition and surface structure among CFIPs, CMIPs, and CFEPs. The molar ratios of glucose to mannose in CFIPs, glucose to xylose in CMIPs, and xylose to glucose in CFEPs were 7.57: 1.6, 7.26: 1.81, and 5.44: 2.98 respectively. Moreover, CFEPs exhibited significantly (p < 0.05) higher chemical antioxidant capacity compared to CMIPs and CFIPs. Surprisingly, CFEP treatment didn't show a significant effect in protecting against H2O2-induced oxidative damage in RAW 264.7 cells. After 3 d of treatment, the levels of ROS, MDA, and MPO in the CFIPs group exhibited a significant (p < 0.05) reduction by 37.82 %, 68.15 %, and 22.77 % respectively. Additionally, the ACP and AKP increased by 60.33 % and 96.99 %. Additionally, C. militaris polysaccharides (CMPs) were found to effectively improve UC by activating the MyD88/NF-κB signaling pathway in vivo. These findings confirm the distinct physicochemical properties of these three types of CMP and their potential for development into antioxidant-rich anti-inflammatory health foods.