Catechol-O-Methyltransferase Loss Drives Cell-Specific Nociceptive Signaling via the Enteric Catechol-O-Methyltransferase/microRNA-155/Tumor Necrosis Factor α Axis

Colonic epithelial-derived FGF1 drives intestinal stem cell commitment toward goblet cells to suppress inflammatory bowel disease

Understanding the molecular mechanisms that regulate intestinal epithelial cell (IEC) renewal provides potential targets for inflammatory bowel disease (IBD). Growing evidence has highlighted the importance of epithelial signals in regulating intestinal stem cell (ISC) differentiation. However, it remains unclear which IEC-derived cytokines can precisely regulate ISC commitment toward specific mature cells. Here we systematically analyze all fibroblast growth factors (FGFs) expression and find that colonic FGF1 levels are inversely correlated with the severity of IBD in mouse models and patients. IEC-specific Fgf1 deletion leads to impaired goblet cell differentiation and exacerbated colitis, while pharmacological administration of recombinant FGF1 (rFGF1) alleviates colitis by enhancing goblet cell differentiation and improving colonic epithelial integrity. Mechanistic studies reveal that rFGF1 directs ISC differentiation toward goblet cells via FGFR2-TCF4-ATOH1 signaling axis. In conclusion, our study identifies an epithelial niche-derived FGF1 that regulates ISC commitment toward goblet cells, shedding light on strategies for treating IBD.

Intestinal organoid coculture systems: current approaches, challenges, and future directions

The intestinal microenvironment represents a complex and dynamic ecosystem, comprising a diverse range of epithelial and nonepithelial cells, a protective mucus layer, and a diverse community of gut microbiota. Understanding the intricate interplay between these components is essential for uncovering the mechanisms underlying intestinal health and disease. The development of intestinal organoids, three-dimensional (3-D) mini-intestines that closely mimic the architecture, cellular diversity, and functionality of the intestine, offers a powerful platform for investigating different aspects of intestinal physiology and pathology. However, current intestinal organoid models, mainly adult stem cell-derived organoids, lack the nonepithelial and microbial components of the intestinal microenvironment. As such, several coculture systems have been developed to coculture intestinal organoids with other intestinal elements including microbes (bacteria and viruses) and immune, stromal, and neural cells. These coculture models allow researchers to recreate the complex intestinal environment and study the intricate cross talk between different components of the intestinal ecosystem under healthy and pathological conditions. Currently, there are several approaches and methodologies to establish intestinal organoid cocultures, and each approach has its own strengths and limitations. This review discusses the existing methods for coculturing intestinal organoids with different intestinal elements, focusing on the methodological approaches, strengths and limitations, and future directions.

Cerebrospinal fluid profiles of targeted metabolomics on neurotransmitters in patients with post-neurosurgical bacterial meningitis

Background

Post-neurosurgical bacterial meningitis (PNBM) is a severe complication in patients receiving neurosurgical treatments. Pathogens and neuroinflammation have been reported to influence metabolites in the microenvironment of the central nervous system. However, information about the relationship between neurotransmitter levels and PNBM is still limited. In this study, we aimed to investigate the diagnostic potential of neurotransmitters for PNBM in the patients with stroke.

Methods

In this study, a total of 66 stroke patients were recruited. Among them, 40 patients were complicated with PNBM. We profiled cerebrospinal fluid (CSF) levels of neurotransmitter precursors and metabolites using the targeted metabolomics method, which contained 26 precursors and metabolites of neurotransmitters, using ultra-performance liquid chromatography coupled with mass spectrometry (UPLC/MS).

Results

We found that 14 biomarkers were downregulated but 3,4-dihydroxyphenylacetic acid (DOPAC) was upregulated in the CSF of PNBM patients. Among the biomarkers, D-glutamine (AUC=1.000), Boc-D-Tyr-OH (AUC=0.9447), L(+)-arginine (AUC=0.9418), and DOPAC (AUC=0.9173) had strong diagnostic efficiency for PNBM. Bioinformatic analysis showed that tyrosine metabolism, butanoate metabolism, histidine metabolism, alanine, aspartate and glutamate metabolism, glycerophospholipid metabolism, arginine and proline metabolism, and tryptophan metabolism might be involved in the pathogenesis of PNBM. After reviewing previous studies, we found a probable diverse pathophysiological alteration between PNBM and community-acquired bacterial meningitis.

Conclusions

In summary, we identified downregulated levels of D-glutamine, Boc-D-Tyr-OH, L(+)-arginine, and phenprobamate, and an upregulated level of DOPAC in CSF to have strong diagnostic efficiencies. The results also offered potential targets for the treatment of PNBM.

The role of miRNA in IBS pathogenesis, diagnosis and therapy: The latest thought

IBS is a prevalent clinical condition affecting bowel function. There is a restricted comprehension of its pathogenesis, an absence of particular diagnostic tools, and an insufficiency of efficient pharmacological remedies. MiRNAs are a highly conserved class of non-coding small molecule RNAs, with a length of 20-24 nucleotides. Research has shown the presence of a number of differentially expressed miRNAs in the colonic tissue and peripheral blood of IBS patients. Meanwhile, miRNAs have a critical role in gene expression and the pathology of IBS as they act as significant mediators of post-transcriptional gene silencing. The investigation of miRNA molecular regulatory networks proves useful in examining the convoluted pathogenesis of IBS. This paper presents a review of recent literature on miRNAs associated with IBS, explains how miRNAs contribute to the development of IBS, and assesses the potential usefulness of miRNA analysis for diagnosing and treating IBS.

Macrophages and Gut Barrier Function: Guardians of Gastrointestinal Health in Post-Inflammatory and Post-Infection Responses

The gut barrier is essential for protection against pathogens and maintaining homeostasis. Macrophages are key players in the immune system, are indispensable for intestinal health, and contribute to immune defense and repair mechanisms. Understanding the multifaceted roles of macrophages can provide critical insights into maintaining and restoring gastrointestinal (GI) health. This review explores the essential role of macrophages in maintaining the gut barrier function and their contribution to post-inflammatory and post-infectious responses in the gut. Macrophages significantly contribute to gut barrier integrity through epithelial repair, immune modulation, and interactions with gut microbiota. They demonstrate active plasticity by switching phenotypes to resolve inflammation, facilitate tissue repair, and regulate microbial populations following an infection or inflammation. In addition, tissue-resident (M2) and infiltration (M1) macrophages convert to each other in gut problems such as IBS and IBD via major signaling pathways mediated by NF-κB, JAK/STAT, PI3K/AKT, MAPK, Toll-like receptors, and specific microRNAs such as miR-155, miR-29, miR-146a, and miR-199, which may be good targets for new therapeutic approaches. Future research should focus on elucidating the detailed molecular mechanisms and developing personalized therapeutic approaches to fully harness the potential of macrophages to maintain and restore intestinal permeability and gut health.