An overview of Ehlers Danlos syndrome and the link between postural orthostatic tachycardia syndrome and gastrointestinal symptoms with a focus on gastroparesis.

There has been an increasingly reported association between Ehlers-Danlos syndrome (EDS), postural orthostatic tachycardia syndrome (POTS) and gastrointestinal disorders. EDS is a hereditary connective tissue disorder which may manifest as a spectrum of symptoms stemming from collagen defects. The prevalence of EDS is estimated to affect 1 in 5000 individuals which underscores its clinical significance. Notably the hypermobile form (hEDS) accounts for the majority of cases. POTS is characterized by orthostatic intolerance with an increase in heart rate on standing in the absence of hypotension. This condition predominantly affects women between 15 and 45 years of age. Gastrointestinal symptoms in the form of reflux, bloating and abdominal pain significant impact this population. Gastroparesis is a chronic disorder involving symptoms of delayed gastric emptying and may be closely associated with hEDS and POTS, and may be underreported. Autonomic dysfunction associated with hEDS has been proposed as the likely mechanism underlying POTS and gastrointestinal dysfunction though a clear pathophysiological process has not been established.

MYC Induces Oncogenic Stress through RNA Decay and Ribonucleotide Catabolism in Breast Cancer.

Upregulation of MYC is a hallmark of cancer, wherein MYC drives oncogenic gene expression and elevates total RNA synthesis across cancer cell transcriptomes. Although this transcriptional anabolism fuels cancer growth and survival, the consequences and metabolic stresses induced by excess cellular RNA are poorly understood. Herein, we discover that RNA degradation and downstream ribonucleotide catabolism is a novel mechanism of MYC-induced cancer cell death. Combining genetics and metabolomics, we find that MYC increases RNA decay through the cytoplasmic exosome, resulting in the accumulation of cytotoxic RNA catabolites and reactive oxygen species. Notably, tumor-derived exosome mutations abrogate MYC-induced cell death, suggesting excess RNA decay may be toxic to human cancers. In agreement, purine salvage acts as a compensatory pathway that mitigates MYC-induced ribonucleotide catabolism, and inhibitors of purine salvage impair MYC+ tumor progression. Together, these data suggest that MYC-induced RNA decay is an oncogenic stress that can be exploited therapeutically. Significance: MYC is the most common oncogenic driver of poor-prognosis cancers but has been recalcitrant to therapeutic inhibition. We discovered a new vulnerability in MYC+ cancer where MYC induces cell death through excess RNA decay. Therapeutics that exacerbate downstream ribonucleotide catabolism provide a therapeutically tractable approach to TNBC (Triple-negative Breast Cancer) and other MYC-driven cancers.

Maternal gestational diabetes mellitus associates with altered gut microbiome composition and head circumference abnormalities in male offspring.

The impact of gestational diabetes mellitus (GDM) on maternal or infant microbiome trajectory remains poorly understood. Utilizing large-scale longitudinal fecal samples from 264 mother-baby dyads, we present the gut microbiome trajectory of the mothers throughout pregnancy and infants during the first year of life. GDM mothers had a distinct microbiome diversity and composition during the gestation period. GDM leaves fingerprints on the infant's gut microbiome, which are confounded by delivery mode. Further, Clostridium species positively correlate with a larger head circumference at month 12 in male offspring but not females. The gut microbiome of GDM mothers with male fetuses displays depleted gut-brain modules, including acetate synthesis I and degradation and glutamate synthesis II. The gut microbiome of female infants of GDM mothers has higher histamine degradation and dopamine degradation. Together, our integrative analysis indicates that GDM affects maternal and infant gut composition, which is associated with sexually dimorphic infant head growth.

FOXP4 is a Direct YAP1 Target that Promotes Gastric Cancer Stemness and Drives Metastasis.

The Hippo-YAP1 pathway is an evolutionally conserved signaling cascade that controls organ size and tissue regeneration. Dysregulation of Hippo-YAP1 signaling promotes initiation and progression of several types of cancer, including gastric cancer (GC). As the Hippo-YAP1 pathway regulates expression of thousands of genes, it is important to establish which target genes contribute to the oncogenic program driven by YAP1 to identify strategies to circumvent it. Here, we identified a vital role of FOXP4 in YAP1-driven gastric carcinogenesis by maintaining stemness and promoting peritoneal metastasis. Loss of FOXP4 impaired GC spheroid formation and reduced stemness marker expression, while FOXP4 upregulation potentiated cancer cell stemness. RNA-seq analysis revealed SOX12 as downstream target of FOXP4, and functional studies established that SOX12 supports stemness in YAP1-induced carcinogenesis. A small molecule screen identified 42-(2-Tetrazolyl)rapamycin as a FOXP4 inhibitor, and targeting FOXP4 suppressed GC tumor growth and enhanced the efficacy of 5-FU chemotherapy in vivo. Collectively, these findings revealed that FOXP4 upregulation by YAP1 in GC regulates stemness and tumorigenesis by upregulating SOX12. Targeting the YAP1-FOXP4-SOX12 axis represents a potential therapeutic strategy for GC.

Blood microbial signatures associated with mortality in patients with sepsis: A pilot study.

Sepsis is a life-threatening illness caused by the dysregulated host response to infection. Nevertheless, our current knowledge of the microbial landscape in the blood of septic patients is still limited. Next-generation sequencing (NGS) is a sensitive method to quantitatively characterize microbiomes at various sites of the human body. In this study, we analyzed the blood microbial DNA of 22 adult patients with sepsis and 3 healthy subjects. The presence of non-human DNA was identified in both healthy and septic subjects. Septic patients had a markedly altered microbial DNA profile compared to healthy subjects over α- and ß-diversity. Unexpectedly, the patients could be further divided into two subgroups (C1 and C2) based on ß-diversity analysis. C1 patients showed much higher bacteria, viruses, fungi, and archaea abundance, and a higher level of α-diversity (Chao1, Observed and Shannon index) than both C2 patients and healthy subjects. The most striking difference was seen in the case of Streptomyces violaceusniger, Phenylobacterium sp. HYN0004, Caulobacter flavus, Streptomyces sp. 11-1-2, and Phenylobacterium zucineum, the abundance of which was the highest in the C1 group. Notably, C1 patients had a significantly poorer outcome than C2 patients. Moreover, by analyzing the patterns of microbe-microbe interactions in healthy and septic subjects, we revealed that C1 and C2 patients exhibited distinct co-occurrence and co-exclusion relationships. Together, our study uncovered two distinct microbial signatures in the blood of septic patients. Compositional and ecological analysis of blood microbial DNA may thus be useful in predicting mortality of septic patients.

Dual RNA sequencing of Helicobacter pylori and host cell transcriptomes reveals ontologically distinct host-pathogen interaction.

Helicobacter pylori is a highly successful pathogen that poses a substantial threat to human health. However, the dynamic interaction between H. pylori and the human gastric epithelium has not been fully investigated. In this study, using dual RNA sequencing technology, we characterized a cytotoxin-associated gene A (cagA)-modulated bacterial adaption strategy by enhancing the expression of ATP-binding cassette transporter-related genes, metQ and HP_0888, upon coculturing with human gastric epithelial cells. We observed a general repression of electron transport-associated genes by cagA, leading to the activation of oxidative phosphorylation. Temporal profiling of host mRNA signatures revealed the downregulation of multiple splicing regulators due to bacterial infection, resulting in aberrant pre-mRNA splicing of functional genes involved in the cell cycle process in response to H. pylori infection. Moreover, we demonstrated a protective effect of gastric H. pylori colonization against chronic dextran sulfate sodium (DSS)-induced colitis. Mechanistically, we identified a cluster of propionic and butyric acid-producing bacteria, Muribaculaceae, selectively enriched in the colons of H. pylori-pre-colonized mice, which may contribute to the restoration of intestinal barrier function damaged by DSS treatment. Collectively, this study presents the first dual-transcriptome analysis of H. pylori during its dynamic interaction with gastric epithelial cells and provides new insights into strategies through which H. pylori promotes infection and pathogenesis in the human gastric epithelium. IMPORTANCE: Simultaneous profiling of the dynamic interaction between Helicobacter pylori and the human gastric epithelium represents a novel strategy for identifying regulatory responses that drive pathogenesis. This study presents the first dual-transcriptome analysis of H. pylori when cocultured with gastric epithelial cells, revealing a bacterial adaptation strategy and a general repression of electron transportation-associated genes, both of which were modulated by cytotoxin-associated gene A (cagA). Temporal profiling of host mRNA signatures dissected the aberrant pre-mRNA splicing of functional genes involved in the cell cycle process in response to H. pylori infection. We demonstrated a protective effect of gastric H. pylori colonization against chronic DSS-induced colitis through both in vitro and in vivo experiments. These findings significantly enhance our understanding of how H. pylori promotes infection and pathogenesis in the human gastric epithelium and provide evidence to identify targets for antimicrobial therapies.

Idiopathic Slow Transit Constipation: Pathophysiology, Diagnosis, and Management.

Slow transit constipation (STC) has an estimated prevalence of 2-4% of the general population, and although it is the least prevalent of the chronic constipation phenotypes, it more commonly causes refractory symptoms and is associated with significant psychosocial stress, poor quality of life, and high healthcare costs. This review provides an overview of the pathophysiology, diagnosis, and management options in STC. STC occurs due to colonic dysmotility and is thought to be a neuromuscular disorder of the colon. Several pathophysiologic features have been observed in STC, including reduced contractions on manometry, delayed emptying on transit studies, reduced numbers of interstitial cells of Cajal on histology, and reduced amounts of excitatory neurotransmitters within myenteric plexuses. The underlying aetiology is uncertain, but autoimmune and hormonal mechanisms have been hypothesised. Diagnosing STC may be challenging, and there is substantial overlap with the other clinical constipation phenotypes. Prior to making a diagnosis of STC, other primary constipation phenotypes and secondary causes of constipation need to be ruled out. An assessment of colonic transit time is required for the diagnosis and can be performed by a number of different methods. There are several different management options for constipation, including lifestyle, dietary, pharmacologic, interventional, and surgical. The effectiveness of the available therapies in STC differs from that of the other constipation phenotypes, and prokinetics often make up the mainstay for those who fail standard laxatives. There are few available management options for patients with medically refractory STC, but patients may respond well to surgical intervention. STC is a common condition associated with a significant burden of disease. It can present a clinical challenge, but a structured approach to the diagnosis and management can be of great value to the clinician. There are many therapeutic options available, with some having more benefits than others.

LOX-1 acts as an N6-methyladenosine-regulated receptor for Helicobacter pylori by binding to the bacterial catalase.

The role of N6-methyladenosine (m6A) modification of host mRNA during bacterial infection is unclear. Here, we show that Helicobacter pylori infection upregulates host m6A methylases and increases m6A levels in gastric epithelial cells. Reducing m6A methylase activity via hemizygotic deletion of methylase-encoding gene Mettl3 in mice, or via small interfering RNAs targeting m6A methylases, enhances H. pylori colonization. We identify LOX-1 mRNA as a key m6A-regulated target during H. pylori infection. m6A modification destabilizes LOX-1 mRNA and reduces LOX-1 protein levels. LOX-1 acts as a membrane receptor for H. pylori catalase and contributes to bacterial adhesion. Pharmacological inhibition of LOX-1, or genetic ablation of Lox-1, reduces H. pylori colonization. Moreover, deletion of the bacterial catalase gene decreases adhesion of H. pylori to human gastric sections. Our results indicate that m6A modification of host LOX-1 mRNA contributes to protection against H. pylori infection by downregulating LOX-1 and thus reducing H. pylori adhesion.

Intraoperative dexamethasone and chronic postsurgical pain: a propensity score-matched analysis of a large trial.

BACKGROUND: Dexamethasone has been shown to reduce acute pain after surgery, but there is uncertainty as to its effects on chronic postsurgical pain (CPSP). We hypothesised that in patients undergoing major noncardiac surgery, a single intraoperative dose of dexamethasone increases the incidence of CPSP. METHODS: We devised a propensity score-matched analysis of the ENIGMA-II trial CPSP dataset, aiming to compare the incidence of CPSP in patients who had received dexamethasone or not 12 months after major noncardiac surgery. The primary outcome was the incidence of CPSP. We used propensity score matching and inverse probability weighting to balance baseline variables to estimate the average marginal effect of dexamethasone on patient outcomes, accounting for confounding to estimate the average treatment effect on those treated with dexamethasone. RESULTS: We analysed 2999 patients, of whom 116 of 973 (11.9%) receiving dexamethasone reported CPSP, and 380 of 2026 (18.8%) not receiving dexamethasone reported CPSP, unadjusted odds ratio 0.76 (95% confidence interval 0.78-1.00), P=0.052. After propensity score matching, CPSP occurred in 116 of 973 patients (12.2%) receiving dexamethasone and 380 of 2026 patients (13.8%) not receiving dexamethasone, adjusted risk ratio 0.88 (95% confidence interval 0.61-1.27), P=0.493. There was no difference between groups in quality of life or pain interference with daily activities, but 'least pain' (P=0.033) and 'pain right now' (P=0.034) were higher in the dexamethasone group. CONCLUSIONS: Dexamethasone does not increase the risk of chronic postsurgical pain after major noncardiac surgery. CLINICAL TRIAL REGISTRATION: Open Science Framework Registration DOI https://doi.org/10.17605/OSF.IO/ZDVB5.

One-year Outcomes after Discharge from Noncardiac Surgery and Association between Predischarge Complications and Death after Discharge: Analysis of the VISION Prospective Cohort Study.

BACKGROUND: In previous analyses, myocardial injury after noncardiac surgery, major bleeding, and sepsis were independently associated with most deaths in the 30 days after noncardiac surgery, but most of these deaths occurred during the index hospitalization for surgery. The authors set out to describe outcomes after discharge from hospital up to 1 yr after inpatient noncardiac surgery and associations between predischarge complications and postdischarge death up to 1 yr after surgery. METHODS: This study was an analysis of patients discharged after inpatient noncardiac surgery in a large international prospective cohort study across 28 centers from 2007 to 2013 of patients aged 45 yr or older followed to 1 yr after surgery. The study estimated (1) the cumulative postdischarge incidence of death and other outcomes up to a year after surgery and (2) the adjusted time-varying associations between postdischarge death and predischarge complications including myocardial injury after noncardiac surgery, major bleeding, sepsis, infection without sepsis, stroke, congestive heart failure, clinically important atrial fibrillation or flutter, amputation, venous thromboembolism, and acute kidney injury managed with dialysis. RESULTS: Among 38,898 patients discharged after surgery, the cumulative 1-yr incidence was 5.8% (95% CI, 5.5 to 6.0%) for all-cause death and 24.7% (95% CI, 24.2 to 25.1%) for all-cause hospital readmission. Predischarge complications were associated with 33.7% (95% CI, 27.2 to 40.2%) of deaths up to 30 days after discharge and 15.0% (95% CI, 12.0 to 17.9%) up to 1 yr. Most of the association with death was due to myocardial injury after noncardiac surgery (15.6% [95% CI, 9.3 to 21.9%] of deaths within 30 days, 6.4% [95% CI, 4.1 to 8.7%] within 1 yr), major bleeding (15.0% [95% CI, 8.3 to 21.7%] within 30 days, 4.7% [95% CI, 2.2 to 7.2%] within 1 yr), and sepsis (5.4% [95% CI, 2.2 to 8.6%] within 30 days, 2.1% [95% CI, 1.0 to 3.1%] within 1 yr). CONCLUSIONS: One in 18 patients 45 yr old or older discharged after inpatient noncardiac surgery died within 1 yr, and one quarter were readmitted to the hospital. The risk of death associated with predischarge perioperative complications persists for weeks to months after discharge.

Flattening the biological age curve by improving metabolic health: to taurine or not to taurine, that' s the question.

The aging population is an important issue around the world especially in developed countries. Although medical advances have substantially extended life span, the same cannot be said for the duration of health span. We are seeing increasing numbers of elderly people who are frail and/or have multiple chronic conditions; all of these can affect the quality of life of the elderly population as well as increase the burden on the healthcare system. Aging is mechanistically related to common medical conditions such as diabetes mellitus, ischemic heart disease, cognitive decline, and frailty. A recently accepted concept termed 'Accelerated Biological Aging' can be diagnosed when a person's biological age-as measured by biomarkers of DNA methylation-is older than their corresponding chronological age. Taurine, a conditionally essential amino acid, has received much attention in the past few years. A substantial number of animal studies have provided a strong scientific foundation suggesting that this amino acid can improve cellular and metabolic health, including blood glucose control, so much that it has been labelled one of the 'longevity amino acids'. In this review article, we propose the rationale that an adequately powered randomized-controlled-trial (RCT) is needed to confirm whether taurine can meaningfully improve metabolic and microbiome health, and biological age. This trial should incorporate certain elements in order to provide the much-needed evidence to guide doctors, and also the community at large, to determine whether this promising and inexpensive amino acid is useful in improving human metabolic health.

The molecular classification of cancer-associated fibroblasts on a pan-cancer single-cell transcriptional atlas.

BACKGROUND: Cancer-associated fibroblasts (CAFs), integral to the tumour microenvironment, are pivotal in cancer progression, exhibiting either pro-tumourigenic or anti-tumourigenic functions. Their inherent phenotypic and functional diversity allows for the subdivision of CAFs into various subpopulations. While several classification systems have been suggested for different cancer types, a unified molecular classification of CAFs on a single-cell pan-cancer scale has yet to be established. METHODS: We employed a comprehensive single-cell transcriptomic atlas encompassing 12 solid tumour types. Our objective was to establish a novel molecular classification and to elucidate the evolutionary trajectories of CAFs. We investigated the functional profiles of each CAF subtype using Single-Cell Regulatory Network Inference and Clustering and single-cell gene set enrichment analysis. The clinical relevance of these subtypes was assessed through survival curve analysis. Concurrently, we employed multiplex immunofluorescence staining on tumour tissues to determine the dynamic changes of CAF subtypes across different tumour stages. Additionally, we identified the small molecule procyanidin C1 (PCC1) as a target for matrix-producing CAF (matCAF) using molecular docking techniques and further validated these findings through in vitro and in vivo experiments. RESULTS: In our investigation of solid tumours, we identified four molecular clusters of CAFs: progenitor CAF (proCAF), inflammatory CAF (iCAF), myofibroblastic CAF (myCAF) and matCAF, each characterised by distinct molecular traits. This classification was consistently applicable across all nine studied solid tumour types. These CAF subtypes displayed unique evolutionary pathways, functional roles and clinical relevance in various solid tumours. Notably, the matCAF subtype was associated with poorer prognoses in several cancer types. The targeting of matCAF using the identified small molecule, PCC1, demonstrated promising antitumour activity. CONCLUSIONS: Collectively, the various subtypes of CAFs, particularly matCAF, are crucial in the initiation and progression of cancer. Focusing therapeutic strategies on targeting matCAF in solid tumours holds significant potential for cancer treatment.

H. pylori-induced NF-κB-PIEZO1-YAP1-CTGF axis drives gastric cancer progression and cancer-associated fibroblast-mediated tumour microenvironment remodelling.

BACKGROUND: Gastric cancer (GC) is one of the most common tumours in East Asia countries and is associated with Helicobacter pylori infection. H. pylori utilizes virulence factors, CagA and VacA, to up-regulate pro-inflammatory cytokines and activate NF-κB signaling. Meanwhile, the PIEZO1 upregulation and cancer-associated fibroblast (CAF) enrichment were found in GC progression. However, the mechanisms of PIEZO1 upregulation and its involvement in GC progression have not been fully elucidated. METHODS: The CAF enrichment and clinical significance were investigated in animal models and primary samples. The expression of NF-κB and PIEZO1 in GC was confirmed by immunohistochemistry staining, and expression correlation was analysed in multiple GC datasets. GSEA and Western blot analysis revealed the YAP1-CTGF axis regulation by PIEZO1. The stimulatory effects of CTGF on CAFs were validated by the co-culture system and animal studies. Patient-derived organoid and peritoneal dissemination models were employed to confirm the role of the PIEZO1-YAP1-CTGF cascade in GC. RESULTS: Both CAF signature and PIEZO1 were positively correlated with H. pylori infection. PIEZO1, a mechanosensor, was confirmed as a direct downstream of NF-κB to promote the transformation from intestinal metaplasia to GC. Mechanistic studies revealed that PIEZO1 transduced the oncogenic signal from NF-κB into YAP1 signaling, a well-documented oncogenic pathway in GC progression. PIEZO1 expression was positively correlated with the YAP1 signature (CTGF, CYR61, and c-Myc, etc.) in primary samples. The secreted CTGF by cancer cells stimulated the CAF infiltration to form a stiffened collagen-enrichment microenvironment, thus activating PIEZO1 to form a positive feedback loop. Both PIEZO1 depletion by shRNA and CTGF inhibition by Procyanidin C1 enhanced the efficacy of 5-FU in suppressing the GC cell peritoneal metastasis. CONCLUSION: This study elucidates a novel driving PIEZO1-YAP1-CTGF force, which opens a novel therapeutic avenue to block the transformation from precancerous lesions to GC. H. pylori-NF-κB activates the PIEZO1-YAP1-CTGF axis to remodel the GC microenvironment by promoting CAF infiltration. Targeting PIEZO1-YAP1-CTGF plus chemotherapy might serve as a potential therapeutic option to block GC progression and peritoneal metastasis.

Lower gut abundance of Eubacterium rectale is linked to COVID-19 mortality.

Introduction: Emerging preclinical and clinical studies suggest that altered gut microbiome composition and functions are associated with coronavirus 2019 (COVID- 19) severity and its long-term complications. We hypothesize that COVID-19 outcome is associated with gut microbiome status in population-based settings. Methods: Gut metagenomic data of the adult population consisting of 2871 subjects from 16 countries were obtained from ExperimentHub through R, while the dynamic death data of COVID-19 patients between January 22, 2020 and December 8, 2020 in each country was acquired from Johns Hopkins Coronavirus Resource Center. An adjusted stable mortality rate (SMR) was used to represent these countries' mortality and correlated with the mean relative abundance (mRA) of healthy adult gut microbiome species. Results: After excluding bacterial species with low prevalence (prevalence <0.2 in the included countries), the ß-diversity was significantly higher in the countries with high SMR when compared with those with median or low SMR (p <0.001). We then identified the mRA of two butyrate producers, Eubacterium rectale and Roseburia intestinalis, that were negatively correlated with SMR during the study period. And the reduction of these species was associated with severer COVID-19 manifestation. Conclusion: Population-based microbiome signatures with the stable mortality rate of COVID-19 in different countries suggest that altered gut microbiome composition and functions are associated with mortality of COVID-19.

Population sepsis incidence, mortality, and trends in Hong Kong between 2009-2018 using clinical and administrative data.

BACKGROUND: Sepsis surveillance using electronic health record (EHR)-based data may provide more accurate epidemiologic estimates than administrative data, but experience with this approach to estimate population-level sepsis burden is lacking. METHODS: This was a retrospective cohort study including all adults admitted to publicly-funded hospitals in Hong Kong between 2009-2018. Sepsis was defined as clinical evidence of presumed infection (clinical cultures and treatment with antibiotics) and concurrent acute organ dysfunction (≥2 point increase in baseline SOFA score). Trends in incidence, mortality, and case fatality risk (CFR) were modelled by exponential regression. Performance of the EHR-based definition was compared with 4 administrative definitions using 500 medical record reviews. RESULTS: Among 13,550,168 hospital episodes during the study period, 485,057 (3.6%) had sepsis by EHR-based criteria with 21.5% CFR. In 2018, age- and sex-adjusted standardized sepsis incidence was 759 per 100,000 (relative +2.9%/year [95%CI 2.0, 3.8%] between 2009-2018) and standardized sepsis mortality was 156 per 100,000 (relative +1.9%/year [95%CI 0.9,2.9%]). Despite decreasing CFR (relative -0.5%/year [95%CI -1.0, -0.1%]), sepsis accounted for an increasing proportion of all deaths (relative +3.9%/year [95%CI 2.9, 4.9%]). Medical record reviews demonstrated that the EHR-based definition more accurately identified sepsis than administrative definitions (AUC 0.91 vs 0.52-0.55, p < 0.001). CONCLUSIONS: An objective EHR-based surveillance definition demonstrated an increase in population-level standardized sepsis incidence and mortality in Hong Kong between 2009-2018 and was much more accurate than administrative definitions. These findings demonstrate the feasibility and advantages of an EHR-based approach for widescale sepsis surveillance.

Carnobacterium maltaromaticum boosts intestinal vitamin D production to suppress colorectal cancer in female mice.

Carnobacterium maltaromaticum was found to be specifically depleted in female patients with colorectal cancer (CRC). Administration of C. maltaromaticum reduces intestinal tumor formation in two murine CRC models in a female-specific manner. Estrogen increases the attachment and colonization of C. maltaromaticum via increasing the colonic expression of SLC3A2 that binds to DD-CPase of this bacterium. Metabolomic and transcriptomic profiling unveils the increased gut abundance of vitamin D-related metabolites and the mucosal activation of vitamin D receptor (VDR) signaling in C. maltaromaticum-gavaged mice in a gut microbiome- and VDR-dependent manner. In vitro fermentation system confirms the metabolic cross-feeding of C. maltaromaticum with Faecalibacterium prausnitzii to convert C. maltaromaticum-produced 7-dehydrocholesterol into vitamin D for activating the host VDR signaling. Overall, C. maltaromaticum colonizes the gut in an estrogen-dependent manner and acts along with other microbes to augment the intestinal vitamin D production to activate the host VDR for suppressing CRC.

Crosstalk between gut microbiota and RNA N6-methyladenosine modification in cancer.

The gut microbiota plays a crucial role in regulating various host metabolic, immune, and neuroendocrine functions, and has a significant impact on human health. Several lines of evidence suggest that gut dysbiosis is associated with a variety of diseases, including cancer. The gut microbiota can impact the development and progression of cancer through a range of mechanisms, such as regulating cell proliferation and death, modulating the host immune response, and altering the host metabolic state. Gene regulatory programs are considered critical mediators between the gut microbiota and host phenotype, of which RNA N6-methyladenosine (m6A) modifications have attracted much attention recently. Aberrant m6A modifications have been shown to play a crucial role in cancer development. This review aims to provide an overview of the diverse roles of gut microbiota and RNA m6A modifications in cancer and highlight their potential interactions in cancer development.

The E2F1-HOXB9/PBX2-CDK6 axis drives gastric tumorigenesis and serves as a therapeutic target in gastric cancer.

Homeobox genes include HOX and non-HOX genes. HOX proteins play fundamental roles during ontogenesis by interacting with other non-HOX gene-encoded partners and performing transcriptional functions, whereas aberrant activation of HOX family members drives tumorigenesis. In this study, gastric cancer (GC) expression microarray data indicated that HOXB9 is a prominent upregulated HOX member in GC samples significantly associated with clinical outcomes and advanced TNM stages. However, the functional role of HOXB9 in GC remains contradictory in previous reports, and the regulatory mechanisms are elusive. By in silico and experimental analyses, we found that HOXB9 was upregulated by a vital cell cycle-related transcription factor, E2F1. Depleting HOXB9 causes G1-phase cell cycle arrest by downregulating CDK6 and a subset of cell cycle-related genes. Meanwhile, HOXB9 contributes to cell division and maintains the cytoskeleton in GC cells. We verified that HOXB9 interacts with PBX2 to form a heterodimer, which transcriptionally upregulates CDK6. Knocking down CDK6 can phenocopy the tumor-suppressive effects caused by HOXB9 depletion. Blocking HOXB9 can enhance the anti-tumor effect of CDK6 inhibitors. In conclusion, we elucidate the oncogenic role of HOXB9 in GC and reveal CDK6 as its potent downstream effector. The E2F1-HOXB9/PBX2-CDK6 axis represents a novel mechanism driving gastric carcinogenesis and conveys prognostic and therapeutic implications. © 2023 The Pathological Society of Great Britain and Ireland.