-
Engineering (Beijing, China) Apr 2024Intestinal homeostasis is maintained by specialized host cells and the gut microbiota. Wnt/β-catenin signaling is essential for gastrointestinal development and...
Intestinal homeostasis is maintained by specialized host cells and the gut microbiota. Wnt/β-catenin signaling is essential for gastrointestinal development and homeostasis, and its dysregulation has been implicated in inflammation and colorectal cancer. Axin1 negatively regulates activated Wnt/β-catenin signaling, but little is known regarding its role in regulating host-microbial interactions in health and disease. Here, we aim to demonstrate that intestinal Axin1 determines gut homeostasis and host response to inflammation. Axin1 expression was analyzed in human inflammatory bowel disease datasets. To explore the effects and mechanism of intestinal Axin1 in regulating intestinal homeostasis and colitis, we generated new mouse models with conditional knockout in intestinal epithelial cell (IEC; ) and Paneth cell (PC; ) to compare with control ( ; LoxP: locus of X-over, P1) mice. We found increased Axin1 expression in the colonic epithelium of human inflammatory bowel disease (IBD). mice exhibited altered goblet cell spatial distribution, PC morphology, reduced lysozyme expression, and enriched (). The absence of intestinal epithelial and PC Axin1 decreased susceptibility to dextran sulfate sodium (DSS)-induced colitis . and mice became more susceptible to DSS-colitis after cohousing with control mice. Treatment with reduced DSS-colitis severity. Antibiotic treatment did not change the IEC proliferation in the mice. However, the intestinal proliferative cells in mice with antibiotic treatment were reduced compared with those in mice without treatment. These data suggest non-colitogenic effects driven by the gut microbiome. In conclusion, we found that the loss of intestinal Axin1 protects against colitis, likely driven by epithelial Axin1 and Axin1-associated . Our study demonstrates a novel role of Axin1 in mediating intestinal homeostasis and the microbiota. Further mechanistic studies using specific Axin1 mutations elucidating how Axin1 modulates the microbiome and host inflammatory response will provide new therapeutic strategies for human IBD.
PubMed: 38911180
DOI: 10.1016/j.eng.2023.06.007 -
Biomedicine & Pharmacotherapy =... Jul 2024Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the mucosa of the colon and rectum. UC is characterized by recurrent episodes, often... (Review)
Review
Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the mucosa of the colon and rectum. UC is characterized by recurrent episodes, often necessitating lifelong medication use, imposing a significant burden on patients. Current conventional and advanced treatments for UC have the disadvantages of insufficient efficiency, susceptibility to drug resistance, and notable adverse effects. Therefore, developing effective and safe drugs has become an urgent need. Autophagy is an intracellular degradation process that plays an important role in intestinal homeostasis. Emerging evidence suggests that aberrant autophagy is involved in the development of UC, and modulating autophagy can effectively alleviate experimental colitis. A growing number of studies have established that autophagy can interplay with endoplasmic reticulum stress, gut microbiota, apoptosis, and the NLRP3 inflammasome, all of which contribute to the pathogenesis of UC. In addition, a variety of intestinal epithelial cells, including absorptive cells, goblet cells, and Paneth cells, as well as other cell types like neutrophils, antigen-presenting cells, and stem cells in the gut, mediate the development of UC through autophagy. To date, many studies have found that natural products hold the potential to exert therapeutic effects on UC by regulating autophagy. This review focuses on the possible effects and pharmacological mechanisms of natural products to alleviate UC with autophagy as a potential target in recent years, aiming to provide a basis for new drug development.
Topics: Autophagy; Humans; Colitis, Ulcerative; Biological Products; Animals; Gastrointestinal Microbiome
PubMed: 38865850
DOI: 10.1016/j.biopha.2024.116891 -
Scientific Reports Jun 2024Paneth cells (PCs), a subset of intestinal epithelial cells (IECs) found at the base of small intestinal crypts, play an essential role in maintaining intestinal...
Paneth cells (PCs), a subset of intestinal epithelial cells (IECs) found at the base of small intestinal crypts, play an essential role in maintaining intestinal homeostasis. Altered PCs function is associated with diverse intestinal pathologies, including ileal Crohn's disease (CD). CD patients with ileal involvement have been previously demonstrated to display impairment in PCs and decreased levels of anti-microbial peptides. Although the immunosuppressive drug Azathioprine (AZA) is widely used in CD therapy, the impact of AZA on IEC differentiation remains largely elusive. In the present study, we hypothesized that the orally administered drug AZA also exerts its effect through modulation of the intestinal epithelium and specifically via modulation of PC function. AZA-treated CD patients exhibited an ileal upregulation of AMPs on both mRNA and protein levels compared to non-AZA treated patients. Upon in vitro AZA stimulation, intestinal epithelial cell line MODE-K exhibited heightened expression levels of PC marker in concert with diminished cell proliferation but boosted mitochondrial OXPHOS activity. Moreover, differentiation of IECs, including PCs differentiation, was boosted in AZA-treated murine small intestinal organoids and was associated with decreased D-glucose consumption and decreased growth rates. Of note, AZA treatment strongly decreased Lgr5 mRNA expression as well as Ki67 positive cells. Further, AZA restored dysregulated PCs associated with mitochondrial dysfunction. AZA-dependent inhibition of IEC proliferation is accompanied by boosted mitochondria function and IEC differentiation into PC.
Topics: Crohn Disease; Azathioprine; Paneth Cells; Humans; Cell Differentiation; Animals; Mice; Intestinal Mucosa; Female; Male; Ileum; Adult; Organoids; Epithelial Cells; Cell Proliferation; Middle Aged; Cell Line; Severity of Illness Index
PubMed: 38839896
DOI: 10.1038/s41598-024-63730-4 -
The Journal of Biological Chemistry May 2024Lysozyme is a β-1,4-glycosidase that hydrolyzes the polysaccharide backbone of bacterial cell walls. With an additional bactericidal function mediated by a separate...
Lysozyme is a β-1,4-glycosidase that hydrolyzes the polysaccharide backbone of bacterial cell walls. With an additional bactericidal function mediated by a separate protein domain, lysozyme is considered a uniquely important antimicrobial molecule contributing to the host's innate immune response to infection. Elevated lysozyme production is found in various inflammatory conditions while patients with genetic risks for inflammatory bowel diseases demonstrate abnormal lysozyme expression, granule packaging, and secretion in Paneth cells. However, it remains unclear how a gain- or loss-of-function in host lysozyme may impact the host inflammatory responses to pathogenic infection. We challenged Lyz1 and ectopic Lyz1-expressing (Villin-Lyz1) mice with S. Typhimurium and then comprehensively assessed the inflammatory disease progression. We conducted proteomics analysis to identify molecules derived from human lysozyme-mediated processing of live Salmonella. We examined the barrier-impairing effects of these identified molecules in human intestinal epithelial cell monolayer and enteroids. Lyz1 mice are protected from infection in terms of morbidity, mortality, and barrier integrity, whereas Villin-Lyz1 mice demonstrate exacerbated infection and inflammation. The growth and invasion of Salmonella in vitro are not affected by human or chicken lysozyme, whereas lysozyme encountering of live Salmonella stimulates the release of barrier-disrupting factors, InvE-sipC and Lpp1, which directly or indirectly impair the tight junctions. The direct engagement of host intestinal lysozyme with an enteric pathogen such as Salmonella promotes the release of virulence factors that are barrier-impairing and pro-inflammatory. Controlling lysozyme function may help alleviate the inflammatory progression.
PubMed: 38823640
DOI: 10.1016/j.jbc.2024.107424 -
World Journal of Gastroenterology May 2024Autoimmune enteropathy (AIE) is a rare disease whose diagnosis and long-term prognosis remain challenging, especially for adult AIE patients.
BACKGROUND
Autoimmune enteropathy (AIE) is a rare disease whose diagnosis and long-term prognosis remain challenging, especially for adult AIE patients.
AIM
To improve overall understanding of this disease's diagnosis and prognosis.
METHODS
We retrospectively analyzed the clinical, endoscopic and histopathological characteristics and prognoses of 16 adult AIE patients in our tertiary medical center between 2011 and 2023, whose diagnosis was based on the 2007 diagnostic criteria.
RESULTS
Diarrhea in AIE patients was characterized by secretory diarrhea. The common endoscopic manifestations were edema, villous blunting and mucosal hyperemia in the duodenum and ileum. Villous blunting (100%), deep crypt lymphocytic infiltration (67%), apoptotic bodies (50%), and mild intraepithelial lymphocytosis (69%) were observed in the duodenal biopsies. Moreover, there were other remarkable abnormalities, including reduced or absent goblet cells (duodenum 94%, ileum 62%), reduced or absent Paneth cells (duodenum 94%, ileum 69%) and neutrophil infiltration (duodenum 100%, ileum 69%). Our patients also fulfilled the 2018 diagnostic criteria but did not match the 2022 diagnostic criteria due to undetectable anti-enterocyte antibodies. All patients received glucocorticoid therapy as the initial medication, of which 14/16 patients achieved a clinical response in 5 (IQR: 3-20) days. Immunosuppressants were administered to 9 patients with indications of steroid dependence (6/9), steroid refractory status (2/9), or intensified maintenance medication (1/9). During the median of 20.5 months of follow-up, 2 patients died from multiple organ failure, and 1 was diagnosed with non-Hodgkin's lymphoma. The cumulative relapse-free survival rates were 62.5%, 55.6% and 37.0% at 6 months, 12 months and 48 months, respectively.
CONCLUSION
Certain histopathological findings, including a decrease or disappearance of goblet and Paneth cells in intestinal biopsies, might be potential diagnostic criteria for adult AIE. The long-term prognosis is still unsatisfactory despite corticosteroid and immunosuppressant medications, which highlights the need for early diagnosis and novel medications.
Topics: Humans; Female; Male; Retrospective Studies; Adult; Middle Aged; Prognosis; Biopsy; Glucocorticoids; Polyendocrinopathies, Autoimmune; Ileum; Duodenum; Diarrhea; Intestinal Mucosa; Immunosuppressive Agents; Aged; Young Adult; Endoscopy, Gastrointestinal
PubMed: 38817655
DOI: 10.3748/wjg.v30.i19.2523 -
BioRxiv : the Preprint Server For... Apr 2024Glial cells of the enteric nervous system (ENS) interact closely with the intestinal epithelium and secrete signals that influence epithelial cell proliferation and...
Glial cells of the enteric nervous system (ENS) interact closely with the intestinal epithelium and secrete signals that influence epithelial cell proliferation and barrier formation . Whether these interactions are important however, is unclear because previous studies reached conflicting conclusions [1]. To better define the roles of enteric glia in steady state regulation of the intestinal epithelium, we characterized the glia in closest proximity to epithelial cells and found that the majority express in both mice and humans. To test their functions using an unbiased approach, we genetically depleted PLP1 cells in mice and transcriptionally profiled the small and large intestines. Surprisingly, glial loss had minimal effects on transcriptional programs and the few identified changes varied along the gastrointestinal tract. In the ileum, where enteric glia had been considered most essential for epithelial integrity, glial depletion did not drastically alter epithelial gene expression but caused a modest enrichment in signatures of Paneth cells, a secretory cell type important for innate immunity. In the absence of PLP1 glia, Paneth cell number was intact, but a subset appeared abnormal with irregular and heterogenous cytoplasmic granules, suggesting a secretory deficit. Consistent with this possibility, ileal explants from glial-depleted mice secreted less functional lysozyme than controls with corresponding effects on fecal microbial composition. Collectively, these data suggest that enteric glia do not exert broad effects on the intestinal epithelium but have an essential role in regulating Paneth cell function and gut microbial ecology.
PubMed: 38659931
DOI: 10.1101/2024.04.15.589545 -
Metastasis of colon cancer requires Dickkopf-2 to generate cancer cells with Paneth cell properties.BioRxiv : the Preprint Server For... Apr 2024Metastasis is the leading cause of cancer-related mortality. Paneth cells provide stem cell niche factors in homeostatic conditions, but the underlying mechanisms of...
Metastasis is the leading cause of cancer-related mortality. Paneth cells provide stem cell niche factors in homeostatic conditions, but the underlying mechanisms of cancer stem cell niche development are unclear. Here we report that Dickkopf-2 (DKK2) is essential for the generation of cancer cells with Paneth cell properties during colon cancer metastasis. Splenic injection of -knockout (KO) cancer organoids into C57BL/6 mice resulted in a significant reduction of liver metastases. Transcriptome analysis showed reduction of Paneth cell markers such as lysozymes in KO organoids. Single cell RNA sequencing analyses of murine metastasized colon cancer cells and patient samples identified the presence of lysozyme positive cells with Paneth cell properties including enhanced glycolysis. Further analyses of transcriptome and chromatin accessibility suggested Hepatocyte nuclear factor 4-alpha (HNF4A) as a downstream target of DKK2. Chromatin immunoprecipitation followed by sequencing analysis revealed that HNF4A binds to the promoter region of , a well-known transcription factor for Paneth cell differentiation. In the liver metastatic foci, DKK2 knockout rescued HNF4A protein levels followed by reduction of lysozyme positive cancer cells. Taken together, DKK2-mediated reduction of HNF4A protein promotes the generation of lysozyme positive cancer cells with Paneth cell properties in the metastasized colon cancers.
PubMed: 38659853
DOI: 10.1101/2024.04.12.589235 -
Journal of Proteome Research May 2024Alcohol consumption perturbs the gut immune barrier and ultimately results in alcoholic liver diseases, but little is known about how immune-related cells in the gut are...
Alcohol consumption perturbs the gut immune barrier and ultimately results in alcoholic liver diseases, but little is known about how immune-related cells in the gut are perturbed in this process. In this study, we employed laser capture microdissection and a label-free proteomics approach to investigate the consequences of alcohol exposure to the proteomes of crypts and villi in the proximal small intestine. Intestinal tissues from alcohol-fed and pair-fed mice were microdissected to selectively capture cells in the crypts and villi regions, followed by one-pot protein digestion and data-independent LC-MS/MS analysis. We successfully identified over 3000 proteins from each of the crypt or villi regions equivalent to ∼3000 cells. Analysis of alcohol-treated tissues indicated an enhanced alcohol metabolism and reduced levels of α-defensins in crypts, alongside increased lipid metabolism and apoptosis in villi. Immunofluorescence imaging further corroborated the proteomic findings. Our work provides a detailed profiling of the proteomic changes in the compartments of the mouse small intestine and aids in molecular-level understanding of alcohol-induced tissue damage.
Topics: Animals; Intestine, Small; Proteomics; Mice; Ethanol; Tandem Mass Spectrometry; Proteome; Laser Capture Microdissection; Chromatography, Liquid; Intestinal Mucosa; Mice, Inbred C57BL; Male; Apoptosis; Lipid Metabolism
PubMed: 38655769
DOI: 10.1021/acs.jproteome.4c00037 -
Ecotoxicology and Environmental Safety Jun 2024The intricate architecture of the intestinal epithelium, crucial for nutrient absorption, is constantly threatened by environmental factors. The epithelium undergoes...
The intricate architecture of the intestinal epithelium, crucial for nutrient absorption, is constantly threatened by environmental factors. The epithelium undergoes rapid turnover, which is essential for maintaining homeostasis, under the control of intestinal stem cells (ISCs). The central regulator, Wnt/β-catenin signaling plays a key role in intestinal integrity and turnover. Despite its significance, the impact of environmental factors on this pathway has been largely overlooked. This study, for the first time, investigates the influence of Cd on the intestinal Wnt signaling pathway using a mouse model. In this study, male BALB/c mice were administered an environmentally relevant Cd dose (0.98 mg/kg) through oral gavage to investigate the intestinal disruption and Wnt signaling pathway. Various studies, including histopathology, immunohistochemistry, RT-PCR, western blotting, ELISA, intestinal permeability assay, and flow cytometry, were conducted to study Cd-induced changes in the intestine. The canonical Wnt signaling pathway experienced significant downregulation as a result of sub-chronic Cd exposure, which caused extensive damage throughout the small intestine. Increased intestinal permeability and a skewed immune response were also observed. To confirm that Wnt signaling downregulation is the key driver of Cd-induced gastrointestinal toxicity, mice were co-exposed to LiCl (a recognized Wnt activator) and Cd. The results clearly showed that the harmful effects of Cd could be reversed, which is strong evidence that Cd mostly damages the intestine through the Wnt/β-catenin signalling axis. In conclusion, this research advances the current understanding of the role of Wnt/β catenin signaling in gastrointestinal toxicity caused by diverse environmental pollutants.
Topics: Animals; Male; Mice; beta Catenin; Cadmium; Inflammation; Intestinal Mucosa; Intestines; Mice, Inbred BALB C; Wnt Signaling Pathway
PubMed: 38640798
DOI: 10.1016/j.ecoenv.2024.116337 -
International Journal of Biological... 2024The intestine is critical for not only processing nutrients but also protecting the organism from the environment. These functions are mainly carried out by the...
The intestine is critical for not only processing nutrients but also protecting the organism from the environment. These functions are mainly carried out by the epithelium, which is constantly being self-renewed. Many genes and pathways can influence intestinal epithelial cell proliferation. Among them is mTORC1, whose activation increases cell proliferation. Here, we report the first intestinal epithelial cell (IEC)-specific knockout () of an amino acid transporter capable of activating mTORC1. We show that the transporter, SLC7A5, is highly expressed in mouse intestinal crypt and reduces mTORC1 signaling. Surprisingly, adult intestinal crypts have increased cell proliferation but reduced mature Paneth cells. Goblet cells, the other major secretory cell type in the small intestine, are increased in the crypts but reduced in the villi. Analyses with scRNA-seq and electron microscopy have revealed dedifferentiation of Paneth cells in mice, leading to markedly reduced secretory granules with little effect on Paneth cell number. Thus, SLC7A5 likely regulates secretory cell differentiation to affect stem cell niche and indirectly regulate cell proliferation.
Topics: Animals; Mice; Amino Acid Transport Systems; Cell Differentiation; Cell Proliferation; Large Neutral Amino Acid-Transporter 1; Mechanistic Target of Rapamycin Complex 1
PubMed: 38617535
DOI: 10.7150/ijbs.94297