Age-Related Mucus Barrier Dysfunction in Mice Is Related to the Changes in Muc2 Mucin in the Colon

Ephedra sinica polysaccharide regulate the anti-inflammatory immunity of intestinal microecology and bacterial metabolites in rheumatoid arthritis

Introduction

Ephedra sinica polysaccharide (ESP) exerts substantial therapeutic effects on rheumatoid arthritis (RA). However, the mechanism through which ESP intervenes in RA remains unclear. A close correlation has been observed between enzymes and derivatives in the gut microbiota and the inflammatory immune response in RA.

Methods

A type II collagen-induced arthritis (CIA) mice model was treated with Ephedra sinica polysaccharide. The therapeutic effect of ESP on collagen-induced arthritis mice was evaluated. The anti-inflammatory and cartilage-protective effects of ESP were also evaluated. Additionally, metagenomic sequencing was performed to identify changes in carbohydrate-active enzymes and resistance genes in the gut microbiota of the ESP-treated CIA mice. Liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry were performed to observe the levels of serum metabolites and short-chain fatty acids in the gut. Spearman's correlational analysis revealed a correlation among the gut microbiota, antibiotic-resistance genes, and microbiota-derived metabolites.

Results

ESP treatment significantly reduced inflammation levels and cartilage damage in the CIA mice. It also decreased the levels of pro-inflammatory cytokines interleukin (IL)-6, and IL-1-β and protected the intestinal mucosal epithelial barrier, inhibiting inflammatory cell infiltration and mucosal damage. Here, ESP reduced the TLR4, MyD88, and TRAF6 levels in the synovium, inhibited the p65 expression and pp65 phosphorylation in the NF-κB signaling pathway, and blocked histone deacetylase (HDAC1 and HDAC2) signals. ESP influenced the gut microbiota structure, microbial carbohydrate-active enzymes, and microbial resistance related to resistance genes. ESP increased the serum levels of L-tyrosine, sn-glycero-3-phosphocholine, octadecanoic acid, N-oleoyl taurine, and decreased N-palmitoyl taurine in the CIA mice.

Conclusion

ESP exhibited an inhibitory effect on RA. Its action mechanism may be related to the ability of ESP to effectively reduce pro-inflammatory cytokines levels, protect the intestinal barrier, and regulate the interaction between mucosal immune systems and abnormal local microbiota. Accordingly, immune homeostasis was maintained and the inhibition of fibroblast-like synoviocyte (FLS) proliferation through the HDAC/TLR4/NF-κB pathway was mediated, thereby contributing to its anti-inflammatory and immune-modulating effects.

Unraveling the role of C1GALT1 in abnormal glycosylation and colorectal cancer progression

C1GALT1 plays a pivotal role in colorectal cancer (CRC) development and progression through its involvement in various molecular mechanisms. This enzyme is central to the O-glycosylation process, producing tumor-associated carbohydrate antigens (TACA) like Tn and sTn, which are linked to cancer metastasis and poor prognosis. The interaction between C1GALT1 and core 3 synthase is crucial for the synthesis of core 3 O-glycans, essential for gastrointestinal health and mucosal barrier integrity. Aberrations in this pathway can lead to CRC development. Furthermore, C1GALT1's function is significantly influenced by its molecular chaperone, Cosmc, which is necessary for the proper folding of T-synthase. Dysregulation in this complex interaction contributes to abnormal O-glycan regulation, facilitating cancer progression. Moreover, C1GALT1 affects downstream signaling pathways and cellular behaviors, such as the epithelial-mesenchymal transition (EMT), by modifying O-glycans on key receptors like FGFR2, enhancing cancer cell invasiveness and metastatic potential. Additionally, the enzyme's relationship with MUC1, a mucin protein with abnormal glycosylation in CRC, highlights its role in cancer cell immune evasion and metastasis. Given these insights, targeting C1GALT1 presents a promising therapeutic strategy for CRC, necessitating further research to develop targeted inhibitors or activators. Future efforts should also explore C1GALT1's potential as a biomarker for early diagnosis, prognosis, and treatment response monitoring in CRC, alongside investigating combination therapies to improve patient outcomes.

Phosphatidylethanolamine Improves Postnatal Growth Retardation by Regulating Mucus Secretion of Intestinal Goblet Cells in Piglets

Phosphatidylethanolamine (PE), a multifunctional phospholipid, is necessary for neonate development. This study aimed to explore the impact of the regulation of exogenous PE on postnatal growth retardation (PGR) by improving intestinal barrier function. Thirty-two neonatal pigs were divided into four groups according to their body weight (BW 2.79 ± 0.50 kg or 1.88 ± 0.40 kg) at 7 days old, CON-NBW, PE-NBW, CON-PGR, and PE-PGR. PE was supplemented to NBW piglets and PGR piglets during lactation and post-weaning periods. Compared with the NBW piglets, the growth performance of PGR piglets was lower, while PE improved the poor growth performance. PGR piglets showed injured intestinal morphology, as evidenced by the reduced ratio of villus height to crypt depth (VH/CD) and goblet cell numbers in the jejunum and ileum. PE recovered the intestinal barrier injury by increasing VH/CD and goblet cell numbers. The decreased MUC2 mRNA and protein expressions were observed in the small intestine of PGR piglets, and PE remarkably increased the expression of MUC2. Mechanistically, PE increased the goblet cell differentiation promoting gene spdef mRNA levels and reduced the mRNA expressions involved in endoplasmic reticulum stress in the jejunal and ileal mucosa of PGR piglets. Overall, we found that PE alleviated growth retardation by regulating intestinal health and generalized its application in neonates.

Characterization of intestinal O-glycome in reactive oxygen species deficiency

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation resulting from an inappropriate inflammatory response to intestinal microbes in a genetically susceptible host. Reactive oxygen species (ROS) generated by NADPH oxidases (NOX) provide antimicrobial defense, redox signaling and gut barrier maintenance. NADPH oxidase mutations have been identified in IBD patients, and mucus layer disruption, a critical aspect in IBD pathogenesis, was connected to NOX inactivation. To gain insight into ROS-dependent modification of epithelial glycosylation the colonic and ileal mucin O-glycome of mice with genetic NOX inactivation (Cyba mutant) was analyzed. O-glycans were released from purified murine mucins and analyzed by hydrophilic interaction ultra-performance liquid chromatography in combination with exoglycosidase digestion and mass spectrometry. We identified five novel glycans in ileum and found minor changes in O-glycans in the colon and ileum of Cyba mutant mice. Changes included an increase in glycans with terminal HexNAc and in core 2 glycans with Fuc-Gal- on C3 branch, and a decrease in core 3 glycans in the colon, while the ileum showed increased sialylation and a decrease in sulfated glycans. Our data suggest that NADPH oxidase activity alters the intestinal mucin O-glycans that may contribute to intestinal dysbiosis and chronic inflammation.

Gut microb-aging and its relevance to frailty aging

This review explores 'microb-aging' in the gut and its potential link to frailty aging. We explore this connection through alterations in microbiota's taxonomy and metabolism, as well as with concepts of ecological resilience, pathobionts emergence, and biogeography. We examine microb-aging in interconnected body organs, emphasizing the bidirectional relationship with 'inflammaging'. Finally, we discuss how targeting microb-aging could improve screening, diagnostic, and therapeutic approaches in geriatrics.