Cell fate specification and differentiation in the adult mammalian intestine

An overview of potential of natural compounds to regulate epigenetic modifications in colorectal cancer: a recent update

Colorectal cancer (CRC) remains an alarming global health concern despite advancements in treatment modalities over recent decades. Among the various factors contributing to CRC, this review emphasizes the critical role of epigenetic mechanisms in its pathogenesis and progression. This review also describes the potential role of natural compounds in altering the epigenetic landscape, focused mainly on DNA methylation, histone modification, and non-coding RNAs. Publications from the previous five years were searched and retrieved using well-known search engines and databases like PubMed, Google Scholar, and ScienceDirect. Keywords like CRC/colorectal cancer, CAC/Colitis associated CRC, inflammasomes, epigenetic modulation, genistein, curcumin, quercetin, resveratrol, anthocyanins, sulforaphane, and epigallocatechin-3-gallate were used in various combinations during the search. These natural compounds predominantly affect pathways such as Wnt/β-catenin, NF-κB, and PI3K/AKT to suppress CRC cell proliferation and oxidative stress and enhance anti-inflammation and apoptosis. However, their clinical use is restricted due to their low bioavailability. However, multiple methods exist to overcome challenges like this, including but not limited to structural modifications, nanoparticle encapsulations, bio-enhancers, and novel advanced delivery systems. These methods improve their potential as supportive therapies that target CRC progression epigenetically with fewer side effects. Current research focuses on enhancing epigenetic targeting to control CRC progression while minimizing side effects, emphasizing improved specificity, bioavailability, and efficacy as standalone or synergistic therapies.

Immune modulation for the patterns of epithelial cell death in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disease of the intestine whose primary pathological presentation is the destruction of the intestinal epithelium. The intestinal epithelium, located between the lumen and lamina propria, transmits luminal microbial signals to the immune cells in the lamina propria, which also modulate the intestinal epithelium. In IBD patients, intestinal epithelial cells (IECs) die dysfunction and the mucosal barrier is disrupted, leading to the recruitment of immune cells and the release of cytokines. In this review, we describe the structure and functions of the intestinal epithelium and mucosal barrier in the physiological state and under IBD conditions, as well as the patterns of epithelial cell death and how immune cells modulate the intestinal epithelium providing a reference for clinical research and drug development of IBD. In addition, according to the targeting of epithelial apoptosis and necroptotic pathways and the regulation of immune cells, we summarized some new methods for the treatment of IBD, such as necroptosis inhibitors, microbiome regulation, which provide potential ideas for the treatment of IBD. This review also describes the potential for integrating AI-driven approaches into innovation in IBD treatments.

The Duodenal Microenvironment in Functional Dyspepsia

Functional dyspepsia (FD) is a chronic gastrointestinal disorder without a readily identifiable organic cause, resulting in bothersome upper abdominal symptoms. It is a highly prevalent disorder of which the pathophysiology remains mostly elusive, despite intensive research efforts. However, recent studies have found alterations in the microenvironment of the duodenum in patients with FD. In this review we summarize the duodenal microenvironment in homeostatic conditions and the alterations found in patients with FD, highlighting the similarities and discrepancies between different studies. The most consistent findings, being an impaired duodenal barrier and duodenal immune activation, are reviewed. We discuss the potential triggers for these observed alterations, including psychological comorbidities, luminal alterations and food related triggers. In summary, this review presents the evidence of molecular and cellular changes in patients with FD, with an impaired duodenal barrier and activated mucosal eosinophils and mast cells, challenging the notion that FD is purely functional, and offering different targets for potential future treatments.

Vertically Aligned Nanowires for Longitudinal Intracellular Sampling

Cells are diverse systems with unique molecular profiles that support vital functions, such as energy production and nutrient absorption. Advances in omics have provided valuable insights into these cellular processes, but many of these tools rely on cell lysis, limiting the ability to track dynamic changes over time. To overcome this, methods for longitudinal profiling of living cells have emerged; however, challenges such as low throughput and genetic manipulation still need to be addressed. Nanomaterials, particularly nanowires, offer a promising solution due to their size, high aspect ratios, low cost, simplicity, and potential for high-throughput manufacturing. Here, we present a nanowire-based platform for longitudinal mRNA profiling in living cells using vertically aligned nickel nanowire arrays for efficient mRNA extraction with minimal cellular disruption. We demonstrate its ability to track enhanced green fluorescent protein expression and transcriptomic changes from drug responses in the same cells over time, showcasing the platform's potential for dynamic cellular analysis.

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.

Osteoarthritis treatment via the GLP-1-mediated gut-joint axis targets intestinal FXR signaling

Whether a gut-joint axis exists to regulate osteoarthritis is unknown. In two independent cohorts, we identified altered microbial bile acid metabolism with reduced glycoursodeoxycholic acid (GUDCA) in osteoarthritis. Suppressing farnesoid X receptor (FXR)-the receptor of GUDCA-alleviated osteoarthritis through intestine-secreted glucagon-like peptide 1 (GLP-1) in mice. GLP-1 receptor blockade attenuated these effects, whereas GLP-1 receptor activation mitigated osteoarthritis. Osteoarthritis patients exhibited a lower relative abundance of Clostridium bolteae, which promoted the formation of ursodeoxycholic acid (UDCA), a precursor of GUDCA. Treatment with C. bolteae and Food and Drug Administration-approved UDCA alleviated osteoarthritis through the gut FXR-joint GLP-1 axis in mice. UDCA use was associated with lower risk of osteoarthritis-related joint replacement in humans. These findings suggest that orchestrating the gut microbiota-GUDCA-intestinal FXR-GLP-1-joint pathway offers a potential strategy for osteoarthritis treatment.

Interferon-responsive intestinal BEST4/CA7+ cells are targets of bacterial diarrheal toxins

BEST4/CA7+ cells of the human intestine were recently identified by single-cell RNA sequencing. While their gene expression profile predicts a role in electrolyte balance, BEST4/CA7+ cell function has not been explored experimentally owing to the absence of BEST4/CA7+ cells in mice and the paucity of human in vitro models. Here, we establish a protocol that allows the emergence of BEST4/CA7+ cells in human intestinal organoids. Differentiation of BEST4/CA7+ cells requires activation of Notch signaling and the transcription factor SPIB. BEST4/CA7+ cell numbers strongly increase in response to the cytokine interferon-γ, supporting a role in immunity. Indeed, we demonstrate that BEST4/CA7+ cells generate robust CFTR-mediated fluid efflux when stimulated with bacterial diarrhea-causing toxins and find the norepinephrine-ADRA2A axis as a potential mechanism in blocking BEST4/CA7+ cell-mediated fluid secretion. Our observations identify a central role of BEST4/CA7+ cells in fluid homeostasis in response to bacterial infections.

Microscopic messengers: Extracellular vesicles shaping gastrointestinal health and disease

The field of extracellular vesicles (EVs) is advancing rapidly, and this review aims to synthesize the latest research connected to EVs and the gastrointestinal tract. We will address new and emerging roles for EVs derived from internal sources such as the pancreas and immune system and how these miniature messengers alter organismal health or the inflammatory response within the GI tract. We will examine what is known about external EVs from dietary and bacterial sources and the immense anti-inflammatory, immune-modulatory, and proliferative potential within these nano-sized information carriers. EV interactions with the intestinal and colonic epithelium and associated immune cells at homeostatic and disease states, such as necrotizing enterocolitis (NEC) and inflammatory bowel disease (IBD) will also be covered. We will discuss how EVs are being leveraged as therapeutics or for drug delivery and conclude with a series of unanswered questions in the field.

Advances and applications of gut organoids: modeling intestinal diseases and therapeutic development

Gut organoids are 3D cellular structures derived from adult or pluripotent stem cells, capable of closely replicating the physiological properties of the gut. These organoids serve as powerful tools for studying gut development and modeling the pathogenesis of intestinal diseases. This review provides an in-depth exploration of technological advancements and applications of gut organoids, with a focus on their construction methods. Additionally, the potential applications of gut organoids in disease modeling, microenvironmental simulation, and personalized medicine are summarized. This review aims to offer perspectives and directions for understanding the mechanisms of intestinal health and disease as well as for developing innovative therapeutic strategies.

Lactate controls cancer stemness and plasticity through epigenetic regulation

Tumors arise from uncontrolled cell proliferation driven by mutations in genes that regulate stem cell renewal and differentiation. Intestinal tumors, however, retain some hierarchical organization, maintaining both cancer stem cells (CSCs) and cancer differentiated cells (CDCs). This heterogeneity, coupled with cellular plasticity enabling CDCs to revert to CSCs, contributes to therapy resistance and relapse. Using genetically encoded fluorescent reporters in human tumor organoids, combined with our machine-learning-based cell tracker, CellPhenTracker, we simultaneously traced cell-type specification, metabolic changes, and reconstructed cell lineage trajectories during tumor organoid development. Our findings reveal distinctive metabolic phenotypes in CSCs and CDCs. We find that lactate regulates tumor dynamics, suppressing CSC differentiation and inducing dedifferentiation into a proliferative CSC state. Mechanistically, lactate increases histone acetylation, epigenetically activating MYC. Given that lactate's regulation of MYC depends on the bromodomain-containing protein 4 (BRD4), targeting cancer metabolism and BRD4 inhibitors emerge as a promising strategy to prevent tumor relapse.

Establishment of an Organoid Culture Model Derived from Small Intestinal Epithelium of C57BL/6 Mice and Its Benefits over Tissues

This study aimed to establish an organoid culture model using small intestine tissues from male and female C57BL/6 mice and to compare it with rat organoid cultures derived from frozen tissues. Crypts were isolated from the small intestines of eight-week-old male and female mice and cultured in 3D extracellular matrix with Wnt, R-spondin, and Noggin. In addition, small intestine tissues from sixteen-week-old F344 rats were preserved in a storage solution immediately post-sacrifice and stored at -80°C before being transferred to a nitrogen tank. Upon thawing, crypts from frozen rat tissues failed to develop into organoids due to structural damage, suggesting the need for fresh tissues or optimized preservation methods. In contrast, mouse-derived organoids showed viability for 7 days, with distinct morphological changes and clear differentiation by Day 7. Quantitative real-time PCR analysis revealed that Lgr5, a stem cell marker, showed significantly higher expression in organoids than in tissues, confirming the successful establishment of the organoid culture. Among epithelial markers, the antimicrobial enzyme Lyz1 was more highly expressed in organoids, while Muc2, a key goblet cell marker, was more highly expressed in male tissues. The enterocyte marker Alp exhibited higher expression in male organoids compared to females, with no sex differences in tissues. These findings highlight sex-specific differences in gene expression related to small intestine differentiation and demonstrate the challenges in organoid culture from frozen rat tissues. The results suggest the importance of immediate tissue processing or improved preservation methods for successful organoid cultures.

scRNA-seq of the intestine reveals the key role of mast cells in early gut dysfunction associated with acute pancreatitis

BACKGROUND

Intestinal barrier dysfunction is a prevalent and varied manifestation of acute pancreatitis (AP). Molecular mechanisms underlying the early intestinal barrier in AP remain poorly understood.

AIM

To explore the biological processes and mechanisms of intestinal injury associated with AP, and to find potential targets for early prevention or treatment of intestinal barrier injury.

METHODS

This study utilized single-cell RNA sequencing of the small intestine, alongside in vitro and in vivo experiments, to examine intestinal barrier function homeostasis during the early stages of AP and explore involved biological processes and potential mechanisms.

RESULTS

Seventeen major cell types and 33232 cells were identified across all samples, including normal, AP1 (4x caerulein injections, animals sacrificed 2 h after the last injection), and AP2 (8x caerulein injections, animals sacrificed 4 h after the last injection). An average of 980 genes per cell was found in the normal intestine, compared to 927 in the AP1 intestine and 1382 in the AP2 intestine. B cells, dendritic cells, mast cells (MCs), and monocytes in AP1 and AP2 showed reduced numbers compared to the normal intestine. Enterocytes, brush cells, enteroendocrine cells, and goblet cells maintained numbers similar to the normal intestine, while cytotoxic T cells and natural killer (NK) cells increased. Enterocytes in early AP exhibited elevated programmed cell death and intestinal barrier dysfunction but retained absorption capabilities. Cytotoxic T cells and NK cells showed enhanced pathogen-fighting abilities. Activated MCs, secreted chemokine (C-C motif) ligand 5 (CCL5), promoted neutrophil and macrophage infiltration and contributed to barrier dysfunction.

CONCLUSION

These findings enrich our understanding of biological processes and mechanisms in AP-associated intestinal injury, suggesting that CCL5 from MCs is a potential target for addressing dysfunction.

Piezo1 regulates colon stem cells to maintain epithelial homeostasis through SCD1-Wnt-β-catenin and programming fatty acid metabolism

Piezo1, which maintains the integrity and function of the intestinal epithelial barrier, is essential for colonic epithelial homeostasis. However, whether and how Piezo1 regulates colon stem cell fate remains unclear. Here, we show that Piezo1 inhibition promotes colon stem cell proliferation. Mechanistically, stearoyl-CoA 9-desaturase 1 (SCD1) is downstream of Piezo1 to affect colon stem cell stemness by acting on the Wnt-β-catenin pathway. For mice, the altered colon stem cell stemness after Piezo1 knockdown and activation was accompanied by a reprogrammed fatty acid (FA) metabolism in colon crypts. Notably, we found that GsMTX4 protects injured colon stem cell stemness in mouse and human colitis organoids. Our results elucidated the role of Piezo1 in regulating normal and postinjury colon stem cell fates through SCD1-Wnt-β-catenin and the SCD1-mediated FA desaturation process. These results provide fresh perspectives on the mechanical factors regulating colon stem cell fate and therapeutic strategies for related intestinal diseases.

The balance between IFN-γ and ERK/MAPK signaling activities ensures lifelong maintenance of intestinal stem cells

While the intestinal epithelium has the highest cellular turnover rates in the mammalian body, it is also considered one of the tissues most resilient to aging-related disorders. Here, we reveal an innate protective mechanism that safeguards intestinal stem cells (ISCs) from environmental conditions in the aged intestine. Using in vivo phenotypic analysis, transcriptomics, and in vitro intestinal organoid studies, we show that age-dependent activation of interferon-γ (IFN-γ) signaling and inactivation of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling are responsible for establishing an equilibrium of Lgr5+ ISCs-between active and quiescent states-to preserve the ISC pool during aging. Furthermore, we show that differentiated cells have different sensitivities to each of the two signaling pathways, which may induce aging-related, functional, and metabolic changes in the body. Thus, our findings reveal an exquisitely balanced, age-dependent signaling mechanism that preserves stem cells at the expense of differentiated cells.

R-spondins secreted by human pancreas-derived mesenchymal stromal cells support pancreatic organoid proliferation

Mesenchymal stromal cells (MSC) play a critical role in the stem cell niche, a specialized microenvironment where stem cells reside and interact with surrounding cells and extracellular matrix components. Within the niche, MSC offer structural support, modulate inflammatory response, promote angiogenesis and release specific signaling molecules that influence stem cell behavior, including self-renewal, proliferation and differentiation. In epithelial tissues such as the intestine, stomach and liver, MSC act as an important source of cytokines and growth factors, but not much is known about their role in the pancreas. Our group has established a standardized technology for the generation of pancreatic organoids. Herein, we investigated the role of pancreatic mesenchymal stromal cells in the regulation of human pancreatic organoid proliferation and growth, using this 3D model in a co-culture system. We particularly focused on the capacity of pancreatic MSC to produce R-spondin factors, which are considered critical regulators of epithelial growth. We propose the development of a complex in vitro system that combines organoid technology and mesenchymal stromal cells, thereby promoting the assembloid new research era.

Single-cell RNA sequencing of the holothurian regenerating intestine reveals the pluripotency of the coelomic epithelium

In holothurians, the regenerative process following evisceration involves the development of a 'rudiment' or 'anlage' at the injured end of the mesentery. This regenerating anlage plays a pivotal role in the formation of a new intestine. Despite its significance, our understanding of the molecular characteristics inherent to the constituent cells of this structure has remained limited. To address this gap, we employed state-of-the-art scRNA-seq and hybridization chain reaction fluorescent in situ hybridization analyses to discern the distinct cellular populations associated with the regeneration anlage. Through this approach, we successfully identified 13 distinct cell clusters. Among these, two clusters exhibit characteristics consistent with putative mesenchymal cells, while another four show features akin to coelomocyte cell populations. The remaining seven cell clusters collectively form a large group encompassing the coelomic epithelium of the regenerating anlage and mesentery. Within this large group of clusters, we recognized previously documented cell populations such as muscle precursors, neuroepithelial cells, and actively proliferating cells. Strikingly, our analysis provides data for identifying at least four other cellular populations that we define as the precursor cells of the growing anlage. Consequently, our findings strengthen the hypothesis that the coelomic epithelium of the anlage is a pluripotent tissue that gives rise to diverse cell types of the regenerating intestinal organ. Moreover, our results provide the initial view into the transcriptomic analysis of cell populations responsible for the amazing regenerative capabilities of echinoderms.

Melatonin Alleviates T-2 Toxin-Induced Intestinal Injury by Enhancing Gut Barrier Function and Modulating Microbiota in Weaned Piglets

The T-2 toxin, originating from a Fusarium species, is a mycotoxin that can adversely affect animal health. Melatonin (MT) is a natural hormone recognized for its properties that reduce inflammation and act as an antioxidant. However, MT's capacity to alleviate intestinal harm from T-2 toxin remains incompletely explored. Employing postweaning piglets, this research investigates MT's prophylactic impact on T-2 toxin-induced enterotoxicity. The results indicate that MT improved growth performance in piglets exposed to T-2 toxins while also enhancing intestinal barrier function. Such effects probably stem from MT's ability to reduce colonic oxidative stress and inflammation. Further findings suggest that these changes are closely associated with MT-induced remodeling of intestinal microbiota and an increase in short-chain fatty acid (SCFA) levels in the intestine. MT therefore alleviates T-2 toxin intestinal damage; gut microbiota are the key to this process.

Growth of the maternal intestine during reproduction

The organs of many female animals are remodeled by reproduction. Using the mouse intestine, a striking and tractable model of organ resizing, we find that reproductive remodeling is anticipatory and distinct from diet- or microbiota-induced resizing. Reproductive remodeling involves partially irreversible elongation of the small intestine and fully reversible growth of its epithelial villi, associated with an expansion of isthmus progenitors and accelerated enterocyte migration. We identify induction of the SGLT3a transporter in a subset of enterocytes as an early reproductive hallmark. Electrophysiological and genetic interrogations indicate that SGLT3a does not sustain digestive functions or enterocyte health; rather, it detects protons and sodium to extrinsically support the expansion of adjacent Fgfbp1-positive isthmus progenitors, promoting villus growth. Our findings reveal unanticipated specificity to physiological organ remodeling. We suggest that organ- and state-specific growth programs could be leveraged to improve pregnancy outcomes or prevent maladaptive consequences of such growth.

Therapeutic potential of fecal microbiota transplantation in colorectal cancer based on gut microbiota regulation: from pathogenesis to efficacy

Colorectal cancer (CRC) remains a leading cause of cancer-related deaths worldwide, with its progression intricately linked to gut microbiota dysbiosis. Disruptions in microbial homeostasis contribute to tumor initiation, immune suppression, and inflammation, establishing the microbiota as a key therapeutic target. Fecal microbiota transplantation (FMT) has emerged as a transformative approach to restore microbial balance, enhance immune responses, and reshape the tumor microenvironment. This review explores the mechanisms underlying FMT's therapeutic potential, evaluates its advantages over other microbiota-based interventions, and addresses challenges such as donor selection, safety concerns, and treatment standardization. Looking forward, the integration of FMT into personalized CRC therapies requires robust clinical trials and the identification of predictive biomarkers to optimize its efficacy and safety.

Long-term consumption of moderate amounts of sucrose-sweetened drinks disrupts intestinal barrier function by impairing goblet cell differentiation

While the prolonged consumption of sucrose-containing beverages is known to impact many organs, their specific effects on the small intestine remain elusive. This study aimed to evaluate how regular intake of sucrose, in amounts typically consumed, affects goblet cells, which play a critical role in regulating the mucosal barrier and innate immune defenses in the small intestine. Ten-week-old male ddY mice, a model of diet-induced obesity, were given a regular diet with either plain water or 7% sucrose water. Caloric intake was monitored weekly through food and drink measurements. After 8 weeks, glucose and insulin responses were evaluated following an oral gavage of glucose or sucrose. At 14 weeks, plasma, whole small intestine, and liver samples were collected. Despite achieving an isocaloric state, mice drinking sucrose water showed approximately a 1.5-fold increase in body weight and impaired glucose tolerance. In the small intestine, genes involved in sucrose digestion and absorption (Sis, Sglt1, Glut2, and Glut5) were upregulated, while genes essential for maintaining the intestinal barrier and function (Epcam, Fabp2, Cldn1, Ocln, and Tjp1) were downregulated. Serum levels and mRNA expression of the inflammatory cytokine, interleukin-18 were elevated. Genes responsible for goblet cell differentiation and function (Hes1, Gfi1, Spdef, and Klf4) were downregulated, leading to an increase in immature goblet cells and a decrease in mucin-producing markers (Muc2, Muc4, and Muc13) in the jejunum. The findings underscore that besides obesity, long-term intake of sucrose-containing drinks provokes localized inflammation and disrupts small intestinal barrier function by impairing goblet cell differentiation and activity.

Intestinal Foxl1+ cell-derived CXCL12 maintains epithelial homeostasis by modulating cellular metabolism

Several mesenchymal cell populations are known to regulate intestinal stem cell (ISC) self-renewal and differentiation. However, the influences of signaling mediators derived from mesenchymal cells other than ISC niche factors on epithelial homeostasis remain poorly understood. Here, we show that host and microbial metabolites, such as taurine and gamma-aminobutyric acid (GABA), act on PDGFRαhigh Foxl1high sub-epithelial mesenchymal cells to regulate their transcription. In addition, we found that CXC chemokine ligand 12 (CXCL12) produced from Foxl1high sub-epithelial mesenchymal cells induces epithelial cell cycle arrest through modulation of the mevalonate-cholesterol synthesis pathway, which suppresses tumor progression in ApcMin/+ mice. We identified that Foxl1high sub-epithelial cells highly express CXCL12 among colonic mesenchymal cells. Foxl1-cre; Cxcl12f/f mice showed an increased number of Ki67+ colonic epithelial cells. CXCL12-induced Ca2+ mobilization facilitated phosphorylation of AMPK in intestinal epithelial cells, which inhibits the maturation of sterol regulatory element-binding proteins (SREBPs) that are responsible for mevalonate pathway activation. Furthermore, Cxcl12 deficiency in Foxl1-expressing cells promoted tumor development in the small and large intestines of ApcMin/+ mice. Collectively, these results demonstrate that CXCL12 secreted from Foxl1high mesenchymal cells manipulates intestinal epithelial cell metabolism, which links to the prevention of tumor progression in ApcMin/+ mice.

Microbiome dysbiosis, neutrophil recruitment and mesenchymal transition of mesothelial cells promotes peritoneal metastasis of colorectal cancer

Peritoneal metastasis (PM) is common in colorectal cancer (CRC), yet its underlying mechanisms are poorly understood. Here, we explored the transcriptional profile of CRC, PM and adjacent tissues revealing key players that facilitate PM. Single-cell analysis of 48 matched samples from 12 patients revealed that remodeling of malignant cells and the tumor microenvironment promotes CRC progression and metastasis. Multiplexed imaging confirmed depletion in PM by enrichment in CRC tissues of neutrophils associated with mucosal immunity disruption, intestinal microbiota dysbiosis and mesenchymal transition of both cancerous and mesothelial cells. Functional analyses in cell lines, organoids and in vivo models demonstrated that dysbiosis promoted inflammation and protumor neutrophil recruitment, while coupled mesenchymal transition of malignant and mesothelial cells disrupted the stromal structure and increased cancer cell invasiveness. Our findings suggest that targeting mesothelial cells and tumor microenvironment remodeling may offer therapeutic strategies for CRC-PM.

PRMT5 Maintains Homeostasis of the Intestinal Epithelium by Modulating Cell Proliferation and Survival

Intestinal homeostasis is sustained by self-renewal of intestinal stem cells, which continuously divide and produce proliferative transit-amplifying (TA) and progenitor cells. Protein arginine methyltransferases 5 (PRMT5) plays a crucial role in regulating homeostasis of various mammalian tissues. However, its function in intestinal homeostasis remains elusive. In this study, conditional knockout of Prmt5 in the mouse intestinal epithelium leads to a reduction in stem cell population, suppression of cell proliferation, and increased cell apoptosis within the intestinal crypts, accompanied with shortened gut length, decreased mouse body weight, and eventual animal mortality. Additionally, Prmt5 deletion or its enzymatic inhibition in intestinal organoids in vitro also shows resembling cellular phenotypes. Methylome profiling identifies 90 potential Prmt5 substrates, which are involved in RNA-related biological processes and cell division. Consistently, Prmt5 depletion in intestinal organoids leads to aberrant alternative splicing in a subset of genes related to the mitotic cell cycle. Furthermore, Prmt5 loss triggers p53-mediated apoptosis in the intestinal epithelium. Collectively, the findings uncover an indispensable role of PRMT5 in promoting cell proliferation and survival, as well as maintaining stem cells in the gut epithelium.

Pig jejunal single-cell RNA landscapes revealing breed-specific immunology differentiation at various domestication stages

Background

Domestication of wild boars into local and intensive pig breeds has driven adaptive genomic changes, resulting in significant phenotypic differences in intestinal immune function. The intestine relies on diverse immune cells, but their evolutionary changes during domestication remain poorly understood at single-cell resolution.

Methods

We performed single-cell RNA sequencing (scRNA-seq) and marker gene analysis on jejunal tissues from wild boars, a Chinese local breed (Jinhua), and an intensive breed (Duroc). Then, we developed an immune cell evaluation system that includes immune scoring, gene identification, and cell communication analysis. Additionally, we mapped domestication-related clustering relationships, highlighting changes in gene expression and immune function.

Results

We generated a single-cell atlas of jejunal tissues, analyzing 26,246 cells and identifying 11 distinct cell lineages, including epithelial and plasma cells, and discovered shared and unique patterns in intestinal nutrition and immunity across breeds. Immune cell evaluation analysis confirmed the conservation and heterogeneity of immune cells, manifested by highly conserved functions of immune cell subgroups, but wild boars possess stronger immune capabilities than domesticated breeds. We also discovered four patterns of domestication-related breed-specific genes related to metabolism, immune surveillance, and cytotoxic functions. Lastly, we identified a unique population of plasma cells with distinctive antibody production in Jinhua pig population.

Conclusions

Our findings provide valuable single-cell insights into the cellular heterogeneity and immune function evolution in the jejunum during pig at various domestication stages. The single-cell atlas also serves as a resource for comparative studies and supports breeding programs aimed at enhancing immune traits in pigs.

Loss of mucin 2 and MHC II molecules causes rare resistance to murine RV infection

Enteric pathogen rotavirus (RV) primarily infects mature enterocytes at the tips of the intestinal villi; however, the role of secretory Paneth and goblet cells in RV pathogenesis remains unappreciated. Atoh1 knockout mice (Atoh1cKO) were used to conditionally delete Paneth, goblet, and enteroendocrine cells in the epithelium to investigate the role of secretory cells in RV infection. Unexpectedly, the number of infected enterocytes and the amount of RV shedding in the stool were greatly decreased following secretory cell deletion. Resistance to RV infection persisted for 7 days after virus inoculation, and Atoh1 knockout mice co-housed with infected wild-type mice were uninfected, based on lack of shedding virus, despite the highly infectious nature of RV. This response was directly proportional to the extent of secretory cell deletion, with infection predominantly occurring in areas containing intact secretory cells. RV infection of Muc2 knockout mice recapitulated the secretory cell deletion phenotype, indicating that goblet cell loss is responsible for attenuated infection. Transcriptome analysis of Atoh1cKO intestine via single-cell RNA sequencing revealed downregulation of MHC II molecules specifically in tip enterocytes, and MHC II-/- mice were likewise resistant to RV infection. These data suggest a previously unknown role for both MUC2 and MHC II expression in susceptibility to RV infection.IMPORTANCERotavirus (RV) is a highly contagious pathogen that primarily infects mature intestinal enterocytes. Murine rotavirus readily infects infant and adult mice, enabling evaluation of RV infection and immunity. We report that mice lacking secretory cells are one of the few genetically modified mouse lines not susceptible to murine rotavirus. Further investigation revealed loss of mucin 2 (MUC2) expression or major histocompatibility complex II (MCH II) expression recapitulated this rare resistance to rotavirus infection, suggesting a previously unrecognized link between secretory cell products and major histocompatibility complex II expression. Furthermore, these mouse models provide a platform to investigate rotavirus pathogenesis.

The Role of Reactive Oxygen Species in Colorectal Cancer Initiation and Progression: Perspectives on Theranostic Approaches

Altered levels of reactive oxygen species (ROS) are recognized as one of the key factors in mediating tumor cell survival in the tissue microenvironment, where they play a role in the initiation, progression and recurrence/relapse of colorectal cancer (CRC). Tumor cells can adapt to oxidative stress (OS) using genetic or metabolic reprogramming in the long or short term. In addition, tumor cells defend themselves through positive regulation of antioxidant molecules, enhancing ROS-driven proliferation. Balanced oxidative eustress levels can influence chemotherapy resistance, allowing tumor cells to survive treatment. Secondary effects of chemotherapy include increased ROS production and redox stress, which can kill cancer cells and eliminate drug resistance. Anticancer treatments based on manipulating ROS levels could represent the gold standard in CRC therapy. Therefore, exploring the modulation of the response to OS in deregulated signaling pathways may lead to the development of new personalized CRC treatments to overcome therapy resistance. In this review, we explore the role of ROS in the initiation and progression of CRC and their diagnostic implications as biomarkers of disease. Furthermore, we focused on the involvement of ROS in different CRC therapeutic options, such as surgery, radiotherapy, theranostic imaging, chemotherapy and immunotherapy and other precision medicine approaches.

Akkermansia muciniphila identified as key strain to alleviate gut barrier injury through Wnt signaling pathway

As the largest mucosal surface, the gut has built a physical, chemical, microbial, and immune barrier to protect the body against pathogen invasion. The disturbance of gut microbiota aggravates pathogenic bacteria invasion and gut barrier injury. Fecal microbiota transplantation (FMT) is a promising treatment for microbiome-related disorders, where beneficial strain engraftment is a significant factor influencing FMT outcomes. The aim of this research was to explore the effect of FMT on antibiotic-induced microbiome-disordered (AIMD) models infected with enterotoxigenic Escherichia coli (ETEC). We used piglet, mouse, and intestinal organoid models to explore the protective effects and mechanisms of FMT on ETEC infection. The results showed that FMT regulated gut microbiota and enhanced the protection of AIMD piglets against ETEC K88 challenge, as demonstrated by reduced intestinal pathogen colonization and alleviated gut barrier injury. Akkermansia muciniphila (A. muciniphila) and Bacteroides fragilis (B. fragilis) were identified as two strains that may play key roles in FMT. We further investigated the alleviatory effects of these two strains on ETEC infection in the AIMD mice model, which revealed that A. muciniphila and B. fragilis relieved ETEC-induced intestinal inflammation by maintaining the proportion of Treg/Th17 cells and epithelial damage by moderately activating the Wnt/β-catenin signaling pathway, while the effect of A. muciniphila was better than B. fragilis. We, therefore, identified whether A. muciniphila protected against ETEC infection using basal-out and apical-out intestinal organoid models. A. muciniphila did protect the intestinal stem cells and stimulate the proliferation and differentiation of intestinal epithelium, and the protective effects of A. muciniphila were reversed by Wnt inhibitor. FMT alleviated ETEC-induced gut barrier injury and intestinal inflammation in the AIMD model. A. muciniphila was identified as a key strain in FMT to promote the proliferation and differentiation of intestinal stem cells by mediating the Wnt/β-catenin signaling pathway.

HMGA1 acts as an epigenetic gatekeeper of ASCL2 and Wnt signaling during colon tumorigenesis

Mutated tumor cells undergo changes in chromatin accessibility and gene expression, resulting in aberrant proliferation and differentiation, although how this occurs is unclear. HMGA1 chromatin regulators are abundant in stem cells and oncogenic in diverse tissues; however, their role in colon tumorigenesis is only beginning to emerge. Here, we uncover a previously unknown epigenetic program whereby HMGA1 amplifies Wnt signaling during colon tumorigenesis driven by inflammatory microbiota and/or Adenomatous polyposis coli (Apc) inactivation. Mechanistically, HMGA1 "opens" chromatin to upregulate the stem cell regulator, Ascl2, and downstream Wnt effectors, promoting stem and Paneth-like cell states while depleting differentiated enterocytes. Loss of just one Hmga1 allele within colon epithelium restrains tumorigenesis and Wnt signaling driven by mutant Apc and inflammatory microbiota. However, HMGA1 deficiency has minimal effects in colon epithelium under homeostatic conditions. In human colon cancer cells, HMGA1 directly induces ASCL2 by recruiting activating histone marks. Silencing HMGA1 disrupts oncogenic properties, whereas reexpression of ASCL2 partially rescues these phenotypes. Further, HMGA1 and ASCL2 are coexpressed and upregulated in human colorectal cancer. Together, our results establish HMGA1 as an epigenetic gatekeeper of Wnt signals and cell state under conditions of APC inactivation, illuminating HMGA1 as a potential therapeutic target in colon cancer.

Frizzled5 controls murine intestinal epithelial cell plasticity through organization of chromatin accessibility

The homeostasis of the intestinal epithelium relies on intricate yet insufficiently understood mechanisms of intestinal epithelial plasticity. Here, we elucidate the pivotal role of Frizzled5 (Fzd5), a Wnt pathway receptor, as a determinant of murine intestinal epithelial cell fate. Deletion of Fzd5 in Lgr5+ intestinal stem cells (ISCs) impairs their self-renewal, whereas its deletion in Krt19+ cells disrupts lineage generation, without affecting crypt integrity in either case. However, a broader deletion of Fzd5 across the epithelium leads to substantial crypt deterioration. Integrated analysis of single-cell RNA sequencing (scRNA-seq) and single-cell ATAC-seq (scATAC-seq) identifies that Fzd5 governs chromatin accessibility, orchestrating the regulation of stem- and lineage-related gene expression mainly in ISCs and progenitor cells. In summary, our findings provide insights into the regulatory role of Fzd5 in governing intestinal epithelial plasticity.

Human organoids and organ-on-chips in coeliac disease research

Coeliac disease (CeD) is an immune-mediated disorder characterised by gluten-triggered inflammation and damage in the small intestine, with lifelong gluten-free diet (GFD) as the only treatment. It is a multifactorial disease, involving genetic and environmental susceptibility factors, and its complexity and lack of comprehensive human model systems have hindered understanding of its pathogenesis and development of new treatments. Therefore, it is crucial to establish systems that recapitulate patient genetic background and the interactions between the small intestinal epithelial barrier, immune cells, and environment that contribute to CeD. In this review, we discuss disease complexity, recent advances in stem cell biology, organoids, tissue co-cultures, and organ-on-chip (OoC) systems that facilitate the development of comprehensive human model systems, and model applications in preclinical studies of potential treatments.

Computing hematopoiesis plasticity in response to genetic mutations and environmental stimulations

Cell plasticity (CP), describing a dynamic cell state, plays a crucial role in maintaining homeostasis during organ morphogenesis, regeneration, and trauma-to-repair biological process. Single-cell-omics datasets provide an unprecedented resource to empower CP analysis. Hematopoiesis offers fertile opportunities to develop quantitative methods for understanding CP. In this study, we generated high-quality lineage-negative single-cell RNA-sequencing datasets under various conditions and introduced a working pipeline named scPlasticity to interrogate naïve and disturbed plasticity of hematopoietic stem and progenitor cells with mutational or environmental challenges. Using embedding methods UMAP or FA, a continuum of hematopoietic development is visually observed in wild type where the pipeline confirms a low proportion of hybrid cells ( P hc , with bias range: 0.4∼0.6) on a transition trajectory. Upon Tet2 mutation, a driver of leukemia, or treatment of DSS, an inducer of colitis, P hc is increased and plasticity of hematopoietic stem and progenitor cells was enhanced. We prioritized several transcription factors and signaling pathways, which are responsible for P hc alterations. In silico perturbation suggests knocking out EGR regulons or pathways of IL-1R1 and β-adrenoreceptor partially reverses P hc promoted by Tet2 mutation and inflammation.

H3K36 methylation regulates cell plasticity and regeneration in the intestinal epithelium

Plasticity is needed during development and homeostasis to generate diverse cell types from stem and progenitor cells. Following differentiation, plasticity must be restricted in specialized cells to maintain tissue integrity and function. For this reason, specialized cell identity is stable under homeostatic conditions; however, cells in some tissues regain plasticity during injury-induced regeneration. While precise gene expression controls these processes, the regulatory mechanisms that restrict or promote cell plasticity are poorly understood. Here we use the mouse small intestine as a model system to study cell plasticity. We find that H3K36 methylation reinforces expression of cell-type-associated genes to maintain specialized cell identity in intestinal epithelial cells. Depleting H3K36 methylation disrupts lineage commitment and activates regenerative gene expression. Correspondingly, we observe rapid and reversible remodelling of H3K36 methylation following injury-induced regeneration. These data suggest a fundamental role for H3K36 methylation in reinforcing specialized lineages and regulating cell plasticity and regeneration.

Matrine disturbs the eimeria necatrix-induced loop of tuft cell-intestinal stem cell-goblet cell by inactivating IL-13/JAK2/STAT3 signaling

As sensors in the gut, tuft cells integrate a complex array of luminal signals to regulate the differentiation fate of intestinal stem cells (ISCs), which trigger a loop of tuft cell-ISC-goblet cell after parasitic infection. As a plant-derived alkaloid, Matrine plays a prominent role for standardizing ISC functions in Eimeria necatrix (EN)-exposed chicks. In this study, we investigated the modulation effects of Matrine on the specific intestinal epithelial cell loop in EN-exposed chicks in vivo and intestinal organoids (IOs) ex vivo. The results showed that EN infection resulted in swelling and hemorrhage of the jejunum, accompanied by the increase in levels of sIgA and inflammatory cytokines (IL-6, IL-1β, and TNF-α). And these inflammatory symptoms were effectively relieved by Matrine intervention. Concurrently, Matrine resisted the EN-induced increase in tuft cell numbers and levels of crucial pro-inflammatory factors (IL-25 and IL-13), while also reversing the differentiation of secretory cell progenitors into goblet cells. Importantly, Matrine impeded the upregulation of the inflammatory signaling pathway JAK2/STAT3 in EN-infected chicks and IOs. Conversely, exogenous supplementation of IL-13 or activation of STAT3 via Colivelin eliminated the standardization of the tuft cell-ISC-goblet cell loop by Matrine. Overall, our findings suggested that Matrine intercepted the tuft cell-ISC-goblet cell loop by reinstating IL-13/JAK2/STAT3 signaling after EN infection.

Dachaihu decoction alleviates septic intestinal epithelial barrier disruption via PI3K/AKT pathway based on transcriptomics and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Dachaihu decoction (DCH) is a famous and ancient TCM formula, extensively utilized for over 1800 years in treating gastrointestinal and inflammatory conditions. Our previous study showed that DCH ameliorated intestinal damage and modulated the gut microflora in septic rats. However, the material basis for these effects and the underlying mechanism of action remains ill-defined. We aimed to explore the pharmaceutical ingredients of DCH and its mechanism in mitigating sepsis-induced intestinal epithelial barrier disruption (IEBD).

MATERIALS AND METHODS

Ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) was used to identify DCH composition. A septic rat model and Caco-2 cells were employed to investigate DCH's effects on IEBD. Transcriptomics and network pharmacology were used to predict potential mechanisms, which were further validated by molecular docking and dynamics simulations. The Modified Murine Sepsis Score (mMSS) and histological assessments were performed. Serum fluorescence intensity of FD4 and the expression of Occludin were evaluated to assess intestinal barrier integrity. And p-PI3K P85, PI3K P85, p-AKT, AKT, Bax and Bcl-2 were determined by Western blot. Cell viability was determined using CCK-8 assay, IL-6 and TNF-α by ELISA and quantitative Real-time PCR (RT-qPCR). The integrity and permeability of single layer of Caco-2 cells were assessed via transepithelial resistance (TEER), alkaline phosphatase (ALP) activity and FD4 permeability.

RESULTS

UHPLC-HRMS identified 180 compounds in DCH. DCH significantly reduced mMSS, improved pathological conditions in the ileum, decreased FD4 serum fluorescence, and enhanced Occludin expression. Transcriptomic and network pharmacology analyses identified the PI3K/AKT pathway as a critical mechanism of action. Molecular docking and dynamics simulations confirmed strong binding of DCH components to PIK3R1. DCH upregulated p-PI3K and p-AKT in ileum tissue of septic rats. DCH improved cell viability, decreased IL-6 and TNF-α, promoted cell survival and Occludin level, and upregulated p-PI3K and p-AKT in LPS-stimulated Caco-2 cells. DCH also maintained TEER, ALP activity and decreased FD4 permeability and these effects were reversed by PI3K inhibitor, LY294002. DCH also downregulated Bax expression and increased Bcl-2 levels in both septic rats and LPS-stimulated Caco-2 cells.

CONCLUSION

DCH ameliorates sepsis-induced IEBD via PI3K/AKT pathway activation, offering a novel therapeutic perspective for sepsis-related intestinal dysfunction.

Yeast cell wall polysaccharides accelerate yet in-feed antibiotic delays intestinal development and maturation via modulating gut microbiome in chickens

BACKGROUND

It is important to promote intestinal development and maturation of chicks for feed digestion and utilization, intestinal health, and disease resistance. This study aimed to investigate the effects of dietary yeast cell wall polysaccharides (YCWP) addition on intestinal development and maturation of chickens and its potential action mechanism.

METHODS

180 one-day-old male Arbor Acres broilers were randomly assigned to three groups containing control (basal diets without any antibiotics or anticoccidial drug), bacitracin methylene disalicylate (BMD)-treated group (50 mg/kg) and YCWP-supplemented group (100 mg/kg).

RESULTS

Compared with control group, in-feed antibiotic BMD continuous administration significantly decreased crypt depth (d 21) and villus height (d 42) along with mucosal maltase activity (d 42) in the ileum (P < 0.05). Also, BMD markedly downregulated gene expression levels of β-catenin, lysozyme, occludin and FABP-2 (d 21) and innate immune related genes CD83 and MHC-I mRNA levels (d 42, P < 0.05), and decreased goblet cell counts in the ileum of chickens (d 21 and d 42, P < 0.05). While, TLR-2, TLR-6 and iNOS mRNA abundances were notably upregulated by BMD treatment (d 42, P < 0.05). Nevertheless, dietary YCWP addition significantly increased the ratio of villus height to crypt depth (d 21), villus surface area (d 21 and d 42), ileal alkaline phosphatase and maltase activities as well as goblet cell (d 21 and d 42) and IgA-producing plasma cell numbers as compared to BMD treatment (d 21, P < 0.05). YCWP addition also upregulated gene expression levels of Lgr5, Wnt/β-catenin signaling pathway related gene (Wnt3, β-catenin, d 21; β-catenin, d 42), intestinal cells proliferation marker Ki-67 and barrier function related genes (occludin, d 21 and d 42, P < 0.05). Moreover, YCWP significantly increased antigen presenting cell marker related genes (MHC-II, d 21; CD83 and MHC-I, d 42), TLR-1, TLR-2 and TLR-6 mRNA levels (d 21, P < 0.05). Cecal microbiome analysis showed that YCWP addition obviously improved cecal microbial composition, as indicated by increasing relative abundance of Fournierella, Psychrobacter and Ruminiclostridium on d 21, and Alistipes and Lactobacillus on d 42, which were positively related with gut development and maturation related indexes (P < 0.05).

CONCLUSION

Collectively, YCWP promoted yet antibiotic BMD delayed intestinal morphological and immunological development linked with modulating gut microbiome in chickens.

Grape Seed Proanthocyanidin Extract Improves Growth Performance and Protects Against Hydrogen Peroxide-Induced Oxidative Stress to the Liver and Intestine in Weaned Hyla Rabbits

Three experiments were conducted to investigate the effects of grape seed proanthocyanidin extract (GSPE) on the growth performance of weaned Hyla rabbits and explore its protective effects against oxidative stress in the liver and intestine by establishing a hydrogen peroxide (H2O2)-induced oxidative stress model. In Exp.1, ninety-six weaned rabbits were used to evaluate the effects of dietary GSPE level on growth performance, and the results showed that a 400 mg/kg GSPE addition increased the feed conversion ratio and liver coefficient and promoted cholesterol metabolism. Exp.2 was conducted to explore the H2O2 concentration required to establish an oxidative stress model, indicating that the model could be established by an intraperitoneal injection of 10% H2O2 at a dosage of 1 mL/kg body weight. In Exp.3, seventy-two weaned rabbits were used to investigate the protective effects against H2O2-induced oxidative stress in the liver and intestine. Our findings showed that 400 mg/kg GSPE supplementation could alleviate the adverse effects of H2O2 injection on the antioxidant capacity in the liver and intestine as well as liver morphology. Therefore, an addition of 400 mg/kg GSPE could improve growth performance and alleviate H2O2-induced adverse effects on the liver and small intestine by enhancing the antioxidative capacity in weaned Hyla rabbits.

Mechanism and regulation of iron absorption throughout the life cycle

BACKGROUND

Iron plays a crucial role through various life stages of human. Iron homeostasis is primarily regulated by iron absorption which is mediated via divalent metal-ion transporter 1 (DMT1), and iron export protein ferroportin (FPN), as there is no active pathway for iron excretion from the body. Recent studies have shown that the magnitude of iron absorption changes through various life stages to meet changing iron requirements.

AIM OF REVIEW

This review aims to provide an overview of recent researches on the regulation of iron absorption throughout mammalian life cycle, with the potential to reveal novel molecules and pathways at special stage of life. Such insights may pave the way for new treatments for disorders associated with aberrant iron homeostasis in the future.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review first summarize the mechanism and regulation of iron absorption throughout various life stages, highlighting that regulatory mechanisms have developed to precisely align iron absorption to iron requirements. In adults, iron absorption is enhanced when body is deficient of iron, conversely, iron absorption is reduced when iron demand decreases via systemic regulator Hepcidin and cellular regulation. In the elderly, age-related inflammation, hormonal changes, and chronic diseases may affect the production of Hepcidin, affecting iron absorption. In infants, intestinal iron absorption and its regulatory mechanism are different from that in adults and there might be an alternative pathway independent of DMT1 and FPN due to high iron absorption. Unique to the fetus, iron is absorbed from maternal stores for its own use through the placenta and is regulated by maternal iron status. This review also proposes directions for further studies, offering promising avenues for developing new treatments for disorders associated with aberrant iron homeostasis.

Intestinal permeability, food antigens and the microbiome: a multifaceted perspective

The gut barrier encompasses several interactive, physical, and functional components, such as the gut microbiota, the mucus layer, the epithelial layer and the gut mucosal immunity. All these contribute to homeostasis in a well-regulated manner. Nevertheless, this frail balance might be disrupted for instance by westernized dietary habits, infections, pollution or exposure to antibiotics, thus diminishing protective immunity and leading to the onset of chronic diseases. Several gaps of knowledge still exist as regards this multi-level interaction. In this review we aim to summarize current evidence linking food antigens, microbiota and gut permeability interference in diverse disease conditions such as celiac disease (CeD), non-celiac wheat sensitivity (NCWS), food allergies (FA), eosinophilic gastrointestinal disorder (EOGID) and irritable bowel syndrome (IBS). Specific food elimination diets are recommended for CeD, NCWS, FA and in some cases for EOGID. Undoubtfully, each of these conditions is very different and quite unique, albeit food antigens/compounds, intestinal permeability and specific microbiota signatures orchestrate immune response and decide clinical outcomes for all of them.

The Mechanism of Baicalin in the Treatment of Mycoplasma Pneumoniae Pneumonia by Regulating NLRP3/Caspase-1 Signaling Pathway

OBJECTIVE

This study investigated the mechanism of baicalin (BIA) attenuating the inflammatory response and lung injury in mycoplasma pneumoniae pneumonia (MPP) mice.

METHODS

MPP mouse models were established and then treated with BIA, azithromycin, or NLRP3 inflammasome activator. Lung wet-to-dry weight (W/D) ratio were weighed. Serum levels of MP-IgM, C-reactive protein (CRP) and bronchoalveolar lavage fluid (BALF) protein were detected by kits, NLRP3/Caspase-1 pathway-related protein levels by Western blot, and IL-1β, IL-18, IL-6 and TNF-α levels by ELISA. HE staining was performed to detect lung injury.

RESULTS

MPP mice showed elevated mouse lung W/D ratio, upregulated serum MP-IgM and CRP levels and BALF protein, and enhanced IL-6 and TNF-α levels, which were reversed by BIA or azithromycin treatment, suggesting that BIA attenuated pulmonary inflammatory response in MPP mice. The lung tissue of MPP mice showed upregulated NLRP3, cleaved Caspase-1,Caspase-1, GSDMD-N and GSDMD levels and raised IL-1β and IL-18 levels, and changes were annulled by BIA or azithromycin treatment, suggesting that BIA inhibited the NLRP3/Caspase-1 pathway activation. NLRP3/Caspase-1 pathway activation partially abrogated the alleviative effect of BIA on the pulmonary inflammatory response of MPP mice.

CONCLUSION

BIA mitigates inflammatory response and lung injury in MPP mice by inhibiting NLRP3/Caspase-1 pathway activation.

Rutin Synergizes with Colistin to Eradicate Salmonellosis in Mice by Enhancing the Efficacy and Reducing the Toxicity

The wide dissemination of multidrug-resistant (MDR) Gram-negative bacteria poses a significant global health and security concern. As developing new antibiotics is generally costly, fastidious, and time-consuming, there is an urgent need for alternative therapeutic strategies to address the gap in antibiotic discovery void. This study aimed to investigate the activity of colistin (CS) in combination with a natural product, rutin (RT), to combat against Salmonella Typhimurium (S. Tm) in vitro and in vivo. The results showed that a combination with RT enabled the potentiation of CS efficacy. Further mechanistic analysis indicated that RT disrupted iron homeostasis to inactivate the PmrA/PmrB system, thereafter reducing the bacterial membrane modifications for enhancing CS binding. Besides enhancing bactericidal activity of CS, RT was also observed to mitigate the CS-induced nephrotoxicity, by which the dosing limitation of CS was overcome for better pathogen clearance. The animal trial eventually confirmed the in vivo synergistic interaction of RT with CS to treat the bacterial infection. To sum up, the present study uncovered the potential of RT as a viable adjuvant of CS to eradicate the infection and protect the hosts, which might serve as a promising alternative to combat infections caused by MDR Gram-negative bacteria.

LSD1 and CoREST2 Potentiate STAT3 Activity to Promote Enteroendocrine Cell Differentiation in Mucinous Colorectal Cancer

Neuroendocrine cells have been implicated in therapeutic resistance and worse overall survival in many cancer types. Mucinous colorectal cancer (mCRC) is uniquely enriched for enteroendocrine cells (EEC), the neuroendocrine cells of the normal colon epithelium, as compared with non-mCRC. Therefore, targeting EEC differentiation may have clinical value in mCRC. In this study, single-cell multiomics uncovered epigenetic alterations that accompany EEC differentiation, identified STAT3 as a regulator of EEC specification, and discovered a rare cancer-specific cell type with enteric neuron-like characteristics. Furthermore, lysine-specific demethylase 1 (LSD1) and CoREST2 mediated STAT3 demethylation and enhanced STAT3 chromatin binding. Knockdown of CoREST2 in an orthotopic xenograft mouse model resulted in decreased primary tumor growth and lung metastases. Collectively, these results provide a rationale for developing LSD1 inhibitors that target the interaction between LSD1 and STAT3 or CoREST2, which may improve clinical outcomes for patients with mCRC. Significance: STAT3 activity mediated by LSD1 and CoREST2 induces enteroendocrine cell specification in mucinous colorectal cancer, suggesting disrupting interaction among LSD1, CoREST2, and STAT3 as a therapeutic strategy to target neuroendocrine differentiation.

Fate mapping in mouse demonstrates early secretory differentiation directly from Lgr5+ intestinal stem cells

The intestinal epithelium has a remarkably high turnover in homeostasis. It remains unresolved how this is orchestrated at the cellular level and how the behavior of stem and progenitor cells ensures tissue maintenance. To address this, we combined quantitative fate mapping in three complementary mouse models with mathematical modeling and single-cell RNA sequencing. Our integrated approach generated a spatially and temporally defined model of crypt maintenance based on two cycling populations: stem cells at the crypt-bottom and transit-amplifying (TA) cells above them. Subsequently, we validated the predictions from the mathematical model, demonstrating that fate decisions between the secretory and absorptive lineages are made within the stem cell compartment, whereas TA cell divisions contribute specifically to the absorptive lineage. These quantitative insights provide further direct evidence for crypt-bottom stem cells as the dominant driver of the intestinal epithelium replenishment.

m6A Reader PRRC2A Promotes Colorectal Cancer Progression via CK1ε-Mediated Activation of WNT and YAP Signaling Pathways

Colorectal cancer (CRC) is the third most common cancer type and the second highest mortality rate among cancers. However, the mechanisms underlying CRC progression remain to be fully understood. In this work, a recently identified m6A-modified RNA reader protein Proline-rich Coiled-coil 2a (PRRC2A) is markedly upregulated in CRC, and intestinal epithelium-specific deletion of Prrc2a significantly suppressed tumor cell growth, stemness, and migratory capacity, while its overexpression promoted these behaviors. Through multiomics analysis, PRRC2A directly targeted CSNK1E (encoding CK1ε), maintaining its RNA stability in an m6A-dependent manner, and that elevated CK1ε can concomitantly result in activation of the WNT and YAP signaling pathways. Interestingly, PRRC2A is directly regulated by the transcription factor ATF1 in its promoter. In summary, the work reveals a novel mechanism by which m6A reader PRRC2A promotes colorectal cancer progression via CK1ε and aberrant upregulation of WNT and YAP signaling. Therefore, PRRC2A and CK1ε can be potential therapeutic targets for treating CRC.

Curcumin alleviated dextran sulfate sodium-induced ulcerative colitis via inhibition of the Wnt/β-catenin signaling pathway and regulation of the differentiation of intestinal stem cells

In this study, we investigated the regulatory role of curcumin in the differentiation of intestinal stem cells (ISCs) in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) model mice and explored whether this effect was mediated by the Wnt/β-catenin signaling pathway. We conducted experiments in DSS-induced UC model mice to observe changes in intestinal morphology through HE staining and detect the expression of key proteins in the Wnt/β-catenin signaling pathway. According to these findings, curcumin was found to have a significant impact on the differentiation of ISCs. These results indicated that curcumin inhibited the Wnt/β-catenin signaling pathway and restored ISC differentiation. The effects of curcumin on the Wnt/β-catenin signaling pathway were further confirmed using Wnt/β-catenin agonists. These findings provide a new perspective for understanding the behavior of ISCs in the context of inflammation and offer new insights into the development of novel therapeutic strategies and drugs for UC.

Single-cell RNA sequencing of the holothurian regenerating intestine reveals the pluripotency of the coelomic epithelium

In holothurians, the regenerative process following evisceration involves the development of a "rudiment" or "anlage" at the injured end of the mesentery. This regenerating anlage plays a pivotal role in the formation of a new intestine. Despite its significance, our understanding of the molecular characteristics inherent to the constituent cells of this structure has remained limited. To address this gap, we employed state-of-the-art scRNA-seq and HCR-FISH analyses to discern the distinct cellular populations associated with the regeneration anlage. Through this approach, we successfully identified thirteen distinct cell clusters. Among these, two clusters exhibit characteristics consistent with putative mesenchymal cells, while another four show features akin to coelomocyte cell populations. The remaining seven cell clusters collectively form a large group encompassing the coelomic epithelium of the regenerating anlage and mesentery. Within this large group of clusters, we recognized previously documented cell populations such as muscle precursors, neuroepithelial cells and actively proliferating cells. Strikingly, our analysis provides data for identifying at least four other cellular populations that we define as the precursor cells of the growing anlage. Consequently, our findings strengthen the hypothesis that the coelomic epithelium of the anlage is a pluripotent tissue that gives rise to diverse cell types of the regenerating intestinal organ. Moreover, our results provide the initial view into the transcriptomic analysis of cell populations responsible for the amazing regenerative capabilities of echinoderms.

Spatial diversity of in vivo tissue immunity

The immune system exhibits spatial diversity in in vivo tissues. Immune cells are strategically distributed within tissues to maintain the organ integrity. Advanced technologies such as intravital imaging and spatial transcriptomics have revealed the spatial heterogeneity of immune cell distribution and function within organs such as the liver, kidney, intestine, and lung. In addition, these technologies visualize nutrient and oxygen environments across tissues. Recent spatial analyses have suggested that a functional immune niche is determined by interactions between immune and non-immune cells in an appropriate nutrient and oxygen environment. Understanding the spatial communication between immune cells, environment, and surrounding non-immune cells is crucial for developing strategies to control immune responses and effectively manage inflammatory diseases.

IFN-γ-dependent regulation of intestinal epithelial homeostasis by NKT cells

Intestinal homeostasis is maintained through the combined functions of epithelial and immune cells that collaborate to preserve the integrity of the intestinal barrier. However, the mechanisms by which immune cell populations regulate intestinal epithelial cell (IEC) homeostasis remain unclear. Here, we use a multi-omics approach to study the immune-epithelial crosstalk and identify CD1d-restricted natural killer T (NKT) cells as key regulators of IEC biology. We find that NKT cells are abundant in the proximal small intestine and show hallmarks of activation at steady state. Subsequently, NKT cells regulate the survival and the transcriptional and cellular composition landscapes of IECs in intestinal organoids, through interferon-γ (IFN-γ) and interleukin-4 secretion. In vivo, lack of NKT cells results in an increase in IEC turnover, while NKT cell activation leads to IFN-γ-dependent epithelial apoptosis. Our findings propose NKT cells as potent producers of cytokines that contribute to the regulation of IEC homeostasis.

Posttranscriptional Regulation of Intestinal Mucosal Growth and Adaptation by Noncoding RNAs in Critical Surgical Disorders

The human intestinal epithelium has an impressive ability to respond to insults and its homeostasis is maintained by well-regulated mechanisms under various pathophysiological conditions. Nonetheless, acute injury and inhibited regeneration of the intestinal epithelium occur commonly in critically ill surgical patients, leading to the translocation of luminal toxic substances and bacteria to the bloodstream. Effective therapies for the preservation of intestinal epithelial integrity and for the prevention of mucosal hemorrhage and gut barrier dysfunction are limited, primarily because of a poor understanding of the mechanisms underlying mucosal disruption. Noncoding RNAs (ncRNAs), which include microRNAs (miRNAs), long ncRNAs (lncRNAs), circular RNAs (circRNAs), and small vault RNAs (vtRNAs), modulate a wide array of biological functions and have been identified as orchestrators of intestinal epithelial homeostasis. Here, we feature the roles of many important ncRNAs in controlling intestinal mucosal growth, barrier function, and repair after injury-particularly in the context of postoperative recovery from bowel surgery. We review recent literature surrounding the relationships between lncRNAs, microRNAs, and RNA-binding proteins and how their interactions impact cell survival, proliferation, migration, and cell-to-cell interactions in the intestinal epithelium. With advancing knowledge of ncRNA biology and growing recognition of the importance of ncRNAs in maintaining the intestinal epithelial integrity, ncRNAs provide novel therapeutic targets for treatments to preserve the gut epithelium in individuals suffering from critical surgical disorders.

Tuft cells in the intestine, immunity and beyond

Tuft cells have gained substantial attention over the past 10 years due to numerous reports linking them with type 2 immunity and microorganism-sensing capacity in many mucosal tissues. This heightened interest is fuelled by their unique ability to produce an array of biological effector molecules, including IL-25, allergy-related eicosanoids, and the neurotransmitter acetylcholine, enabling downstream responses in diverse cell types. Operating through G protein-coupled receptor-mediated signalling pathways reminiscent of type II taste cells in oral taste buds, tuft cells emerge as chemosensory sentinels that integrate luminal conditions, eliciting appropriate responses in immune, epithelial and neuronal populations. How tuft cells promote tissue alterations and adaptation to the variety of stimuli at mucosal surfaces has been explored in multiple studies in the past few years. Since the initial recognition of the role of tuft cells, the discovery of diverse tuft cell effector functions and associated feedback loops have also revealed the complexity of tuft cell biology. Although earlier work largely focused on extraintestinal tissues, novel genetic tools and recent mechanistic studies on intestinal tuft cells established fundamental concepts of tuft cell activation and functions. This Review is an overview of intestinal tuft cells, providing insights into their development, signalling and interaction modules in immunity and other states.