Olfactomedin-4 is a glycoprotein secreted into mucus in active IBD

OLFM4 modulates intestinal inflammation by promoting IL-22+ILC3 in the gut

Group 3 innate lymphoid cells (ILC3s) play key roles in intestinal inflammation. Olfactomedin 4 (OLFM4) is highly expressed in the colon and has a potential role in dextran sodium sulfate-induced colitis. However, the detailed mechanisms underlying the effects of OLFM4 on ILC3-mediated colitis remain unclear. In this study, we identify OLFM4 as a positive regulator of IL-22+ILC3. OLFM4 expression in colonic ILC3s increases substantially during intestinal inflammation in humans and mice. Compared to littermate controls, OLFM4-deficient (OLFM4-/-) mice are more susceptible to bacterial infection and display greater resistance to anti-CD40 induced innate colitis, together with impaired IL-22 production by ILC3, and ILC3s from OLFM4-/-mice are defective in pathogen resistance. Besides, mice with OLFM4 deficiency in the RORγt compartment exhibit the same trend as in OLFM4-/-mice, including colonic inflammation and IL-22 production. Mechanistically, the decrease in IL-22+ILC3 caused by OLFM4 deficiency involves the apoptosis signal-regulating kinase 1 (ASK1)- p38 MAPK signaling-dependent downregulation of RAR-related orphan receptor gamma (RORγt) protein. The OLFM4-metadherin (MTDH) complex upregulates p38/RORγt signaling, which is necessary for IL-22+ILC3 activation. The findings indicate that OLFM4 is a novel regulator of IL-22+ILC3 and essential for modulating intestinal inflammation and tissue homeostasis.

Early intestinal development of chickens divergently selected for high or low 8-wk body weight and a commercial broiler

The early posthatch period is crucial to intestinal development, shaping long-term growth, metabolism, and health of the chick. The objective of this study was to determine the effect of genetic selection on morphological characteristics and gene expression during early intestinal development. Populations of White Plymouth Rocks have been selected for high weight (HWS) and low weight (LWS) for over 63 generations, and some LWS display symptoms of anorexia. Intestinal structure and function of these populations were compared to a commercial broiler Cobb 500 (Cobb) during the perihatch period. Egg weights, yolk-free embryo BW, yolk weights, and jejunal samples from HWS, LWS, and Cobb were collected on embryonic day (e) 17, e19, day of hatch, day (d) 3, d5, and d7 posthatch for histology and gene expression analysis. The RNAscope in-situ hybridization method was used to localize expression of the stem cell marker, olfactomedin 4 (Olfm4). Villus height (VH), crypt depth (CD), and VH/CD were measured from Olfm4 stained images using ImageJ. mRNA abundance for Olfm4, stem cell marker Lgr5, peptide transporter PepT1, goblet cell marker Muc2, marker of proliferation Ki67, and antimicrobial peptide LEAP2 were examined. Two-factor ANOVA was performed for measurements and Turkey's HSD was used for mean separation when appropriate. Cobb were heaviest and LWS the lightest (P < 0.01). at each timepoint. VH increased in Cobb and CD increased in HWS compared to LWS (P < 0.01). PepT1 mRNA was upregulated in LWS (P < 0.01), and Muc2 mRNA was decreased in both HWS and LWS compared to Cobb (P < 0.01). Selection for high or low 8-wk body weight has caused differences in intestinal gene expression and morphology when compared to a commercial broiler.

The role of the Notch signalling pathway in the pathogenesis of ulcerative colitis: from the perspective of intestinal mucosal barrier

Ulcerative colitis is a common digestive disorder worldwide, with increasing incidence in recent years. It is an urgent problem to be solved, as it seriously affects and threatens the health and life of the global population. Studies have shown that dysfunction of the intestinal mucosal barrier is a critical pathogenic factor and molecular basis of ulcerative colitis, and some scholars have described it as a "barrier organ disease." While the Notch signalling pathway affects a series of cellular processes, including proliferation, differentiation, development, migration, and apoptosis. Therefore, it can regulate intestinal stem cells, CD4+ T cells, innate lymphoid cells, macrophages, and intestinal microbiota and intervene in the chemical, physical, immune, and biological mucosal barriers in cases of ulcerative colitis. The Notch signalling pathway associated with the pathogenesis of ulcerative colitis has distinct characteristics, with good regulatory effects on the mucosal barrier. However, research on ulcerative colitis has mainly focused on immune regulation, anti-inflammatory activity, and antioxidant stress; therefore, the study of the Notch signalling pathway suggests the possibility of understanding the pathogenesis of ulcerative colitis from another perspective. In this article we explore the role and mechanism of the Notch signalling pathway in the pathogenesis of ulcerative colitis from the perspective of the intestinal mucosal barrier to provide new targets and theoretical support for further research on the pathogenesis and clinical treatment of ulcerative colitis.

Sympathetic activity regulates epithelial proliferation and wound healing via adrenergic receptor α2A

Innervation of the intestinal mucosa by the sympathetic nervous system is well described but the effects of adrenergic receptor stimulation on the intestinal epithelium remain equivocal. We therefore investigated the effect of sympathetic neuronal activation on intestinal cells in mouse models and organoid cultures, to identify the molecular routes involved. Using publicly available single-cell RNA sequencing datasets we show that the α2A isoform is the most abundant adrenergic receptor in small intestinal epithelial cells. Stimulation of this receptor with norepinephrine or a synthetic specific α2A receptor agonist promotes epithelial proliferation and stem cell function, while reducing differentiation in vivo and in intestinal organoids. In an anastomotic healing mouse model, adrenergic receptor α2A stimulation resulted in improved anastomotic healing, while surgical sympathectomy augmented anastomotic leak. Furthermore, stimulation of this receptor led to profound changes in the microbial composition, likely because of altered epithelial antimicrobial peptide secretion. Thus, we established that adrenergic receptor α2A is the molecular delegate of intestinal epithelial sympathetic activity controlling epithelial proliferation, differentiation, and host defense. Therefore, this receptor could serve as a newly identified molecular target to improve mucosal healing in intestinal inflammation and wounding.

Macrophage and neutrophil heterogeneity at single-cell spatial resolution in human inflammatory bowel disease

Ulcerative colitis and Crohn's disease are chronic inflammatory intestinal diseases with perplexing heterogeneity in disease manifestation and response to treatment. While the molecular basis for this heterogeneity remains uncharacterized, single-cell technologies allow us to explore the transcriptional states within tissues at an unprecedented resolution which could further understanding of these complex diseases. Here, we apply single-cell RNA-sequencing to human inflamed intestine and show that the largest differences among patients are present within the myeloid compartment including macrophages and neutrophils. Using spatial transcriptomics in human tissue at single-cell resolution (CosMx Spatial Molecular Imaging) we spatially localize each of the macrophage and neutrophil subsets identified by single-cell RNA-sequencing and unravel further macrophage diversity based on their tissue localization. Finally, single-cell RNA-sequencing combined with single-cell spatial analysis reveals a strong communication network involving macrophages and inflammatory fibroblasts. Our data sheds light on the cellular complexity of these diseases and points towards the myeloid and stromal compartments as important cellular subsets for understanding patient-to-patient heterogeneity.

Spatial transcriptome unveils a discontinuous inflammatory pattern in proficient mismatch repair colorectal adenocarcinoma

The preexistence of immune cells in the tumor microenvironment substantiates the efficacy of immunotherapy in cancer patients. Although the complex intratumoral immune heterogeneity has been extensively studied in single cell resolution, hi-res spatial investigations are limited. In this study, we performed a spatial transcriptome analysis of 4 colorectal adenocarcinoma specimens and 2 paired distant normal specimens to identify the molecular pattern involved in a discontinuous inflammatory response in pathologically annotated cancer regions. Based on the location of spatially varied gene expression, we unmasked the spatially-varied immune ecosystem and identified the locoregional "warmed-up" immune response in predefined "cold" tumor with substantial infiltration of immune components. This "warmed-up" immune profile was found to be associated with the in-situ copy number variance and the tissue remodeling process. Further, "warmed-up" signature genes indicated improved overall survival in CRC patients obtained from TCGA database.

Stiffness Restricts the Stemness of the Intestinal Stem Cells and Skews Their Differentiation Toward Goblet Cells

BACKGROUND & AIMS

Fibrosis and tissue stiffening are hallmarks of inflammatory bowel disease (IBD). We have hypothesized that the increased stiffness directly contributes to the dysregulation of the epithelial cell homeostasis in IBD. Here, we aim to determine the impact of tissue stiffening on the fate and function of the intestinal stem cells (ISCs).

METHODS

We developed a long-term culture system consisting of 2.5-dimensional intestinal organoids grown on a hydrogel matrix with tunable stiffness. Single-cell RNA sequencing provided stiffness-regulated transcriptional signatures of the ISCs and their differentiated progeny. YAP-knockout and YAP-overexpression mice were used to manipulate YAP expression. In addition, we analyzed colon samples from murine colitis models and human IBD samples to assess the impact of stiffness on ISCs in vivo.

RESULTS

We demonstrated that increasing the stiffness potently reduced the population of LGR5+ ISCs and KI-67+-proliferating cells. Conversely, cells expressing the stem cell marker, olfactomedin-4, became dominant in the crypt-like compartments and pervaded the villus-like regions. Concomitantly, stiffening prompted the ISCs to preferentially differentiate toward goblet cells. Mechanistically, stiffening increased the expression of cytosolic YAP, driving the extension of olfactomedin-4+ cells into the villus-like regions, while it induced the nuclear translocation of YAP, leading to preferential differentiation of ISCs toward goblet cells. Furthermore, analysis of colon samples from murine colitis models and patients with IBD demonstrated cellular and molecular remodeling reminiscent of those observed in vitro.

CONCLUSIONS

Collectively, our findings highlight that matrix stiffness potently regulates the stemness of ISCs and their differentiation trajectory, supporting the hypothesis that fibrosis-induced gut stiffening plays a direct role in epithelial remodeling in IBD.

Comprehensive Analysis of Gene Expression Profiling to Explore Predictive Markers for Eradication Therapy Efficacy against Helicobacter pylori-Negative Gastric MALT Lymphoma

Although radiotherapy is the standard treatment for Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma, eradication therapy using antibiotics and an acid secretion suppressor can sometimes induce complete remission. We explored predictive markers for the response to eradication therapy for gastric MALT lymphoma that were negative for both API2-MALT1 and Hp infection using comprehensive RNA sequence analysis. Among 164 gastric MALT lymphoma patients who underwent eradication therapy as primary treatment, 36 were negative for both the API2-MALT1 fusion gene and Hp infection. Based on eradication therapy efficacy, two groups were established: complete response (CR) and no change (NC). The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that cancer-related genes and infection-related genes were highly expressed in the NC and CR groups, respectively. Based on this finding and transcription factor, gene ontology enrichment, and protein-protein interaction analyses, we selected 16 candidate genes for predicting eradication therapy efficacy. Real-time PCR validation in 36 Hp-negative patients showed significantly higher expression of olfactomedin-4 (OLFM4) and the Nanog homeobox (NANOG) in the CR and NC groups, respectively. OLFM4 and NANOG could be positive and negative predictive markers, respectively, for eradication therapy efficacy against gastric MALT lymphoma that is negative for both API2-MALT1 and Hp infection.

Hypoxia-Driven Changes in a Human Intestinal Organoid Model and the Protective Effects of Hydrolyzed Whey

Many whey proteins, peptides and protein-derived amino acids have been suggested to improve gut health through their anti-oxidant, anti-microbial, barrier-protective and immune-modulating effects. Interestingly, although the degree of hydrolysis influences peptide composition and, thereby, biological function, this important aspect is often overlooked. In the current study, we aimed to investigate the effects of whey protein fractions with different degrees of enzymatic hydrolysis on the intestinal epithelium in health and disease with a novel 2D human intestinal organoid (HIO) monolayer model. In addition, we aimed to assess the anti-microbial activity and immune effects of the whey protein fractions. Human intestinal organoids were cultured from adult small intestines, and a model enabling apical administration of nutritional components during hypoxia-induced intestinal inflammation and normoxia (control) in crypt-like and villus-like HIO was established. Subsequently, the potential beneficial effects of whey protein isolate (WPI) and two whey protein hydrolysates with a 27.7% degree of hydrolysis (DH28) and a 50.9% degree of hydrolysis (DH51) were assessed. In addition, possible immune modulatory effects on human peripheral immune cells and anti-microbial activity on four microbial strains of the whey protein fractions were investigated. Exposure to DH28 prevented paracellular barrier loss of crypt-like HIO following hypoxia-induced intestinal inflammation with a concomitant decrease in hypoxia inducible factor 1 alpha (HIF1α) mRNA expression. WPI increased Treg numbers and Treg expression of cluster of differentiation 25 (CD25) and CD69 and reduced CD4+ T cell proliferation, whereas no anti-microbial effects were observed. The observed biological effects were differentially mediated by diverse whey protein fractions, indicating that (degree of) hydrolysis influences their biological effects. Moreover, these new insights may provide opportunities to improve immune tolerance and promote intestinal health.

A primary cell-based in vitro model of the human small intestine reveals host olfactomedin 4 induction in response to Salmonella Typhimurium infection

Infection research largely relies on classical cell culture or mouse models. Despite having delivered invaluable insights into host-pathogen interactions, both have limitations in translating mechanistic principles to human pathologies. Alternatives can be derived from modern Tissue Engineering approaches, allowing the reconstruction of functional tissue models in vitro. Here, we combined a biological extracellular matrix with primary tissue-derived enteroids to establish an in vitro model of the human small intestinal epithelium exhibiting in vivo-like characteristics. Using the foodborne pathogen Salmonella enterica serovar Typhimurium, we demonstrated the applicability of our model to enteric infection research in the human context. Infection assays coupled to spatio-temporal readouts recapitulated the established key steps of epithelial infection by this pathogen in our model. Besides, we detected the upregulation of olfactomedin 4 in infected cells, a hitherto unrecognized aspect of the host response to Salmonella infection. Together, this primary human small intestinal tissue model fills the gap between simplistic cell culture and animal models of infection, and shall prove valuable in uncovering human-specific features of host-pathogen interplay.

Olfactomedin 4 produces dysplasia but suppresses metastasis of colon cancer

Development of colorectal cancer (CRC) is regulated by a series of genetic and microenvironmental alterations. Olfactomedin 4 (OLFM4) is a secreted glycoprotein that is highly expressed in the gastrointestinal tract and modulates inflammation. However, the role of OLFM4 in CRC is uncertain. Here we aimed to explore the function of OLFM4 in CRC in vivo and in vitro. The mRNA expression of OLFM4 was up-regulated in precursor lesions with dysplasia or ulcerative colitis but was reduced in CRC. OLFM4 neutralizing antibody suppressed inflammation-mediated early-stage CRC formation in an AOM/DSS colitis-associated cancer model. OLFM4 knockdown cells exhibited increased cell proliferation and motility in vitro and in vivo. Ablation of OLFM4 increased tumor growth and metastasis in xenograft experiments. In addition, OLFM4 knockdown cells showed elevated expression of colon cancer stem cell markers including CD133, resulting in increased metastasis via epithelial-mesenchymal transition signaling. This study demonstrated that OLFM4 regulates inflammation and cancer progression differently; ablation of OLFM4 promotes cancer metastasis via stemness and epithelial-mesenchymal transition. These results suggest a new route for controlling cancer progression and metastasis.

Molecular regulation after mucosal injury and regeneration in ulcerative colitis

Ulcerative colitis (UC) is a chronic nonspecific inflammatory disease with a complex etiology. Intestinal mucosal injury is an important pathological change in individuals with UC. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5+) intestinal stem cells (ISCs) exhibit self-renewal and high differentiation potential and play important roles in the repair of intestinal mucosal injury. Moreover, LGR5+ ISCs are intricately regulated by both the Wnt/β-catenin and Notch signaling pathways, which jointly maintain the function of LGR5+ ISCs. Combination therapy targeting multiple signaling pathways and transplantation of LGR5+ ISCs may lead to the development of new clinical therapies for UC.

Pneumococcal pep27-mutant inhibits Wnt5a expression via the regulation of T helper cells to attenuate colitis

Inflammatory bowel disease (IBD) is a chronic gut inflammatory disease characterized by extensive colitis and remission of the symptoms. The incidence rate and prevalence of IBD are increasing worldwide; IBD affects millions of people, has poorly defined etiology, and often results in a failure of pharmacological interventions. Regardless of the cause, mucosal healing is indispensable for the regeneration of inflamed mucosa to ensure intestinal homeostasis. Intranasal immunization with the pneumococcal pep27 mutant (Δpep27) has been reported as an avirulent and live vaccine that has been proposed to suppress immune-regulated disorders, eliciting long-lasting immunity. The dose-dependent activity of Δpep27 in the lungs was measured by transcriptome analysis to investigate the long-lasting immunogenic response against IBD. Novel therapeutic targets based on the modulation of Wnt signaling and T regulatory cells interconnected with other signaling cascades in the context of IBD were investigated by qPCR and immunoblotting. M1/M2 macrophages were quantified by FACS analysis. Dextran sulfate sodium-induced colitis induced significant upregulation of Th2 and Th17 as well as noncanonical Wnt5, which subsequently inhibited regulatory T (Treg) expression. In contrast, Δpep27 immunization significantly attenuated the levels of Wnt5, proinflammatory cytokines, oxidative stress parameters, and infiltration of inflammatory cells and enhanced barrier integrity via T helper cell homeostasis and upregulation of M2 macrophages. The data of the present study suggested that Δpep27-elicited Tregs were able to repress Wnt5a expression, assisting with the restoration of immunological tolerance and providing a robust regenerative and antioxidant milieu.

Identification of useful genes from multiple microarrays for ulcerative colitis diagnosis based on machine learning methods

Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease with an increasing incidence and prevalence worldwide. The diagnosis for UC mainly relies on clinical symptoms and laboratory examinations. As some previous studies have revealed that there is an association between gene expression signature and disease severity, we thereby aim to assess whether genes can help to diagnose UC and predict its correlation with immune regulation. A total of ten eligible microarrays (including 387 UC patients and 139 healthy subjects) were included in this study, specifically with six microarrays (GSE48634, GSE6731, GSE114527, GSE13367, GSE36807, and GSE3629) in the training group and four microarrays (GSE53306, GSE87473, GSE74265, and GSE96665) in the testing group. After the data processing, we found 87 differently expressed genes. Furthermore, a total of six machine learning methods, including support vector machine, least absolute shrinkage and selection operator, random forest, gradient boosting machine, principal component analysis, and neural network were adopted to identify potentially useful genes. The synthetic minority oversampling (SMOTE) was used to adjust the imbalanced sample size for two groups (if any). Consequently, six genes were selected for model establishment. According to the receiver operating characteristic, two genes of OLFM4 and C4BPB were finally identified. The average values of area under curve for these two genes are higher than 0.8, either in the original datasets or SMOTE-adjusted datasets. Besides, these two genes also significantly correlated to six immune cells, namely Macrophages M1, Macrophages M2, Mast cells activated, Mast cells resting, Monocytes, and NK cells activated (P  <  0.05). OLFM4 and C4BPB may be conducive to identifying patients with UC. Further verification studies could be conducted.

OLFM4 deficiency delays the progression of colitis to colorectal cancer by abrogating PMN-MDSCs recruitment

Chronic inflammatory bowel disease (IBD) is strongly associated with the development of colitis-associated tumorigenesis (CAT). Despite recent advances in the understanding of polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) responses in cancer, the mechanisms of these cells during this process remain largely uncharacterized. Here, we discovered a glycoprotein, olfactomedin-4 (OLFM4), was highly expressed in PMN-MDSCs from colitis to colorectal cancer (CRC), and its expression level and PMN-MDSC population positively correlated with the progression of IBD to CRC. Moreover, mice lacking OLFM4 in myeloid cells showed poor recruitment of PMN-MDSCs, impaired intestinal homeostasis, and delayed development from IBD to CRC, and increased response to anti-PD1 therapy. The main mechanism of OLFM4-mediated PMN-MDSC activity involved the NF-κB/PTGS2 pathway, through the binding of LGALS3, a galactoside-binding protein expressed on PMN-MDSCs. Our results showed that the OLFM4/NF-κB/PTGS2 pathway promoted PMN-MDSC recruitment, which played an essential role in the maintenance of intestinal homeostasis, but showed resistance to anti-PD1 therapy in CRC.

Efficient transgenesis and homology-directed gene targeting in monolayers of primary human small intestinal and colonic epithelial stem cells

Two-dimensional (2D) cultures of intestinal and colonic epithelium can be generated using human intestinal stem cells (hISCs) derived from primary tissue sources. These 2D cultures are emerging as attractive and versatile alternatives to three-dimensional organoid cultures; however, transgenesis and gene-editing approaches have not been developed for hISCs grown as 2D monolayers. Using 2D cultured hISCs we show that electroporation achieves up to 80% transfection in hISCs from six anatomical regions with around 64% survival and produces 0.15% transgenesis by PiggyBac transposase and 35% gene edited indels by electroporation of Cas9-ribonucleoprotein complexes at the OLFM4 locus. We create OLFM4-emGFP knock-in hISCs, validate the reporter on engineered 2D crypt devices, and develop complete workflows for high-throughput cloning and expansion of transgenic lines in 3–4 weeks. New findings demonstrate small hISCs expressing the highest OLFM4 levels exhibit the most organoid forming potential and show utility of the 2D crypt device to evaluate hISC function.

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Transgenesis in hISCs exclusively in monolayer cultures

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Electroporation efficiencies up to nearly 80% in SI and colon epithelial stem cells

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Simple high-throughput methods transfect both DNA and Cas9 protein complexes

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A new OLFM4-emGFP hISC line accurately reports stem cell potency in culture

Increased expression of OLFM4 and lysozyme during necrotizing enterocolitis in neonates: an observational research study

Background

In neonatal patients with necrotizing enterocolitis (NEC) the inflammatory response is mediated by a plurality of different proteins. The proteins olfactomedin 4 (OLFM4) and lysozyme (LYZ) are part of the intestinal mucosal defense and especially OLFM4 has rarely been evaluated in neonatal gastrointestinal diseases. The aim of this study was to analyze whether expression levels of both proteins of innate immunity, OLFM4 and lysozyme, were increased during NEC in neonates.

Methods

Intestinal tissues of patients with NEC were examined with immunohistochemical staining of formalin-fixed and paraffin-embedded sections of resected tissue using antibodies against OLFM4 and lysozyme. Staining-positive tissues were semi-quantitatively scored from 0 (no staining), 1 (weak staining), 2 (moderate staining) to 3 (highly intense staining) by two individual investigators. Intestinal tissue of infants with volvulus was used as a control as other intestinal tissue without major inflammation was not available.

Results

Both applied antibodies against OLFM4 showed different staining patterns with higher staining intensity of the antibody OLFM4 (D1E4M). OLFM4 (median score of the antibody OLFM4 (D1E4M): 3.0) and lysozyme (median score: 3.0) are highly expressed in intestinal and immune cells during NEC. Expression of OLFM4 and lysozyme in the control samples with volvulus was observable but significantly lower (median score of the antibody OLFM4 (D1E4M): 1.25; median score of the antibody against LYZ: 2.0; p = 0.033 and p = 0.037, respectively).

Conclusions

Both proteins, OLFM4 and lysozyme, may play a role in the pathogenesis of NEC in neonatal patients, but the exact mechanisms of OLFM4 and lysozyme function and their role in immunological responses have not yet been resolved in detail. These observations add new insights as basis for further large-scale population research.

Single-Cell Transcriptome Analysis Reveals the Role of Pancreatic Secretome in COVID-19 Associated Multi-organ Dysfunctions

The SARS-CoV-2 infection affects the lungs, heart, kidney, intestine, olfactory epithelia, liver, and pancreas and brings forward multi-organ dysfunctions (MODs). However, mechanistic details of SARS-CoV-2-induced MODs are unclear. Here, we have investigated the role of pancreatic secretory proteins to mechanistically link COVID-19 with MODs using single-cell transcriptome analysis. Secretory proteins were identified using the Human Protein Atlas. Gene ontology, pathway, and disease enrichment analyses were used to highlight the role of upregulated pancreatic secretory proteins (secretome). We show that SARS-CoV-2 infection shifts the expression profile of pancreatic endocrine cells to acinar and ductal cell-specific profiles, resulting in increased expression of acinar and ductal cell-specific genes. Among all the secretory proteins, the upregulated expression of IL1B, AGT, ALB, SPP1, CRP, SERPINA1, C3, TFRC, TNFSF10, and MIF was mainly associated with disease of diverse organs. Extensive literature and experimental evidence are used to validate the association of the upregulated pancreatic secretome with the coagulation cascade, complement activation, renin-angiotensinogen system dysregulation, endothelial cell injury and thrombosis, immune system dysregulation, and fibrosis. Our finding suggests the influence of an upregulated secretome on multi-organ systems such as nervous, cardiovascular, immune, digestive, and urogenital systems. Our study provides evidence that an upregulated pancreatic secretome is a possible cause of SARS-CoV-2-induced MODs. This finding may have a significant impact on the clinical setting regarding the prevention of SARS-CoV-2-induced MODs.

Olfactomedin 4 Is a Biomarker for the Severity of Infectious Diseases

Biomarkers of infectious diseases are essential tools for patient monitoring, diagnostics, and prognostics. Here we review recent advances in our understanding of olfactomedin 4 (OLFM4) in neutrophil biology and of OLFM4 as a new biomarker for certain infectious diseases. OLFM4 is a neutrophil-specific granule protein that is expressed in a subset of human and mouse neutrophils. OLFM4 expression is upregulated in many viral and bacterial infections, as well as in malaria. OLFM4 appears to play an important role in regulating host innate immunity against bacterial infection. Further, higher expression of OLFM4 is associated with severity of disease for dengue virus, respiratory syncytial virus, and malaria infections. In addition, higher expression of OLFM4 or a higher percentage of OLFM4 + neutrophils is associated with poorer outcomes in septic patients. OLFM4 is a promising biomarker and potential therapeutic target in certain infectious diseases.

An in vitro chronic damage model impairs inflammatory and regenerative responses in human colonoid monolayers

Acute damage to the intestinal epithelium can be repaired via de-differentiation of mature intestinal epithelial cells (IECs) to a stem-like state, but there is a lack of knowledge on how intestinal stem cells function after chronic injury, such as in inflammatory bowel disease (IBD). We developed a chronic-injury model in human colonoid monolayers by repeated rounds of air-liquid interface and submerged culture. We use this model to understand how chronic intestinal damage affects the ability of IECs to (1) respond to microbial stimulation, using the Toll-like receptor 5 (TLR5) agonist FliC and (2) regenerate and protect the epithelium from further damage. Repeated rounds of damage impair the ability of IECs to regrow and respond to TLR stimulation. We also identify mRNA expression and DNA methylation changes in genes associated with IBD and colon cancer. This methodology results in a human model of recurrent IEC injury like that which occurs in IBD.

GBP4 is an immune-related biomarker for patients with ileocolonic Crohn’s disease by comprehensive analysis

Background: Extensive evidence has shown that immune cell infiltration is associated with the pathogenesis of Crohn’s disease (CD).

Methods: Differentially expressed genes (DEGs) from the GSE179285 dataset in the intestinal mucosa of CD patients and healthy individuals were then identified. The infiltration pattern of 22 immune cell types was assessed using the CIBERSORT algorithm. The DEGs and 22 immune cell types were combined to find the key gene network using weighted gene co-expression network analysis (WGCNA). A linear regression model for the relationship between the expression of the hub genes in CD patients and infiltration of immune cells was also developed. The utility and accuracy of the hub genes for CD diagnosis were assessed using receiver operating characteristic (ROC) analysis. The accuracy of the model was validated using the GSE20881 dataset.

Results: There were 1135 DEGs between the intestinal mucosal tissue of CD patients and healthy individuals. Of these DEGs, 711 genes were upregulated, whereas 424 of them were downregulated. There was also a significant difference in the infiltration of immune cells to the intestinal mucosal between the CD patients and healthy individuals. WGCNA revealed that the turquoise module genes were strongly correlated with the infiltration of M1 macrophages (cor =0.68, p = 10−16). Finally, the expression of GBP4, the identified hub gene, strongly correlated with the infiltration of M1 macrophages (adjusted r-squared =0.661, p < 2×10−16), and is a relatively good marker for CD diagnostic prediction (AUC =0.736). The relationship between GBP4 expression and infiltration of M1 macrophages (adjusted r-squared =0.435, p < 2×10−16) and diagnostic value of the gene (AUC =0.702) were verified using the GSE20881 validation dataset.

Conclusion: The expression of GBP4 is associated with the infiltration of M1 macrophages to the intestinal mucosa of CD patients.

Integrative computational approach identifies immune-relevant biomarkers in ulcerative colitis

Ulcerative colitis is a common inflammatory bowel disease with a complex genetic and immune etiology. Immune infiltration plays a vital role in the development of ulcerative colitis. To explore potential biomarkers for ulcerative colitis and analyze characteristics of immune cell infiltration, we used bioinformatic analyses, including machine learning algorithms, cell type deconvolution methods, and pathway enrichment methods. In this study, we identified 216 differentially expressed mRNAs (DEMs), of which 153 were upregulated, and 63 were downregulated genes. DEMs were mainly enriched in infiltrating neutrophils and regulation of leukocyte migration. Moreover, eight candidate biomarkers, DPP10, MST1L, DPP10‐AS1, CEP55, ACSL1, MGP, OLFM4, and SGK1, were identified. Of these candidate biomarkers, MST1L, OLFM4, and DPP10 were then validated in the GSE48958 dataset and were predicted to be strongly correlated with infiltrating immune cells of ulcerative colitis. The underlying mechanism of these key genes in the development of colitis was also predicted by gene set variation analysis. To further validate these biomarkers' expression in ulcerative colitis, we determined mRNA levels of SGK1, CEP55, ACSL1, OLFM4, and DPP10 in lipopolysaccharides (LPS)‐stimulated Raw264.7 cells by quantitative reverse transcription‐polymerase chain reaction. We also examined SGK1, CEP55, ACSL1, OLFM4, DPP10, and MGP expression in the colon tissues of dextran sodium sulfate‐induced colitis mice. Consistent with the predicted computational results, the mRNA levels of these candidate genes were markedly changed in LPS‐stimulated Raw264.7 cells and inflamed colon tissues. Hence, our findings indicated that these critical genes may act as diagnostic biomarkers for ulcerative colitis and that differential immune infiltration cells may help illustrate the progression of ulcerative colitis.

Post-translational protein deimination signatures in sea lamprey (Petromyzon marinus) plasma and plasma-extracellular vesicles

Lampreys are a jawless vertebrate species belonging to an ancient vertebrate lineage that diverged from a common ancestor with humans ~500 million years ago. The sea lamprey (Petromyzon marinus) has a filter feeding ammocoete larval stage that metamorphoses into a parasitic adult, feeding both on teleost and elasmobranch fish. Lampreys are a valuable comparative model species for vertebrate immunity and physiology due to their unique phylogenetic position, unusual adaptive immune system, and physiological adaptions such as tolerance to salinity changes and urea. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family which catalyses post-translational deimination/citrullination in target proteins, enabling proteins to gain new functions (moonlighting). The identification of deiminated protein targets in species across phylogeny may provide novel insights into post-translational regulation of physiological and pathophysiological processes. Extracellular vesicles (EVs) are membrane vesicles released from cells that carry cargos of small molecules and proteins for cellular communication, involved in both normal and pathological processes. The current study identified deimination signatures in proteins of both total plasma and plasma-EVs in sea lamprey and furthermore reports the first characterisation of plasma-EVs in lamprey. EVs were poly-dispersed in the size range of 40-500 nm, similar to what is observed in other taxa, positive for CD63 and Flotillin-1. Plasma-EV morphology was confirmed by transmission electron microscopy. Assessment of deimination/citrullination signatures in lamprey plasma and plasma-EVs, revealed 72 deimination target proteins involved in immunity, metabolism and gene regulation in whole plasma, and 37 target proteins in EVs, whereof 24 were shared targets. Furthermore, the presence of deiminated histone H3, indicative of gene-regulatory mechanisms and also a marker of neutrophil extracellular trap formation (NETosis), was confirmed in lamprey plasma. Functional protein network analysis revealed some differences in KEGG and GO pathways of deiminated proteins in whole plasma compared with plasma-EVs. For example, while common STRING network clusters in plasma and plasma-EVs included Peptide chain elongation, Viral mRNA translation, Glycolysis and gluconeogenesis, STRING network clusters specific for EVs only included: Cellular response to heat stress, Muscle protein and striated muscle thin filament, Nucleosome, Protein processing in endoplasmic reticulum, Nucleosome and histone deacetylase complex. STRING network clusters specific for plasma were: Adipokinetic hormone receptor activity, Fibrinogen alpha/beta chain family, peptidase S1A, Glutathione synthesis and recycling-arginine, Fructose 1,6-bisphosphate metabolic process, Carbon metabolism and lactate dehydrogenase activity, Post-translational protein phosphorylation, Regulation of insulin-like growth factor transport and clotting cascade. Overall, for the EV citrullinome, five STRING network clusters, 10 KEGG pathways, 15 molecular GO pathways and 29 Reactome pathways were identified, compared with nine STRING network clusters, six KEGG pathways, two Molecular GO pathways and one Reactome pathway specific for whole plasma; while further pathways were shared. The reported findings indicate that major pathways relevant for immunity and metabolism are targets of deimination in lamprey plasma and plasma-EVs, with some differences, and may help elucidating roles for the conserved PAD enzyme family in regulation of immune and metabolic function throughout phylogeny.

Overexpression of Cancer-Associated Stem Cell Gene OLFM4 in the Colonic Epithelium of Patients With Primary Sclerosing Cholangitis

BACKGROUND

To examine immune-epithelial interactions and their impact on epithelial transformation in primary sclerosing cholangitis-associated ulcerative colitis (PSC-UC) using patient-derived colonic epithelial organoid cultures (EpOCs).

METHODS

The EpOCs were originated from colonic biopsies from patients with PSC-UC (n = 12), patients with UC (n = 14), and control patients (n = 10) and stimulated with cytokines previously associated with intestinal inflammation (interferon (IFN) γ and interleukin (IL)-22). Markers of cytokine downstream pathways, stemness, and pluripotency were analyzed by real-time quantitative polymerase chain reaction and immunofluorescence. The OLFM4 expression in situ was assessed by RNAscope and immunohistochemistry.

RESULTS

A distinct expression of stem cell-associated genes was observed in EpOCs derived from patients with PSC-UC, with lower expression of the classical stem-cell marker LGR5 and overexpression of OLFM4, previously associated with pluripotency and early stages of neoplastic transformation in the gastrointestinal and biliary tracts. High levels of OLFM4 were also found ex vivo in colonic biopsies from patients with PSC-UC. In addition, IFNγ stimulation resulted in the downregulation of LGR5 in EpOCs, whereas higher expression of OLFM4 was observed after IL-22 stimulation. Interestingly, expression of the IL-22 receptor, IL22RA1, was induced by IFNγ, suggesting that a complex interplay between these cytokines may contribute to carcinogenesis in PSC-UC.

CONCLUSIONS

Higher expression of OLFM4, a cancer stemness gene induced by IL-22, is present in PSC-UC, suggesting that IL-22 responses may result in alterations of the intestinal stem-cell niche in these patients.

Revisiting an Expression Dataset of Discordant Inflammatory Bowel Disease Twin Pairs Using a Mutation Burden Test Reveals CYP2C18 as a Novel Marker

The aim of this study was to investigate the expression features of discordant inflammatory bowel disease (IBD) twin pairs to identify novel molecular features and markers. We collected an expression dataset of discordant twin pairs with ulcerative colitis and performed integrative analysis to identify the genetic-independent expression features. Through deconvolution of the immune cell populations and tissue expression specificity, we refined the candidate genes for susceptibility to ulcerative colitis. We found that dysregulated immune systems and NOD-related pathways were enriched in the expression network of the discordant IBD twin pairs. Among the identified factors were significantly increased proportions of immune cells, including megakaryocytes, neutrophils, natural killer T cells, and lymphatic endothelial cells. The differentially expressed genes were significantly enriched in a gene set associated with cortical and medullary thymocytes. Finally, by combining these expression features with genetic resources, we identified some candidate genes with potential to serve as novel markers of ulcerative colitis, such as CYP2C18. Ulcerative colitis is a subtype of inflammatory bowel disease and a polygenic disorder. Through integrative analysis, we identified some genes, such as CYP2C18, that are involved in the pathogenesis of IBD as well as some candidate therapeutic targets, such as LOXL2.

Notch and TNF-α signaling promote cytoplasmic accumulation of OLFM4 in intestinal epithelium cells and exhibit a cell protective role in the inflamed mucosa of IBD patients

Notch signaling is activated in the intestinal epithelial cells (IECs) of patients with inflammatory bowel disease (IBD), and contributes to mucosal regeneration. Our previous study indicated that TNF-α and Notch signaling may synergistically promote the expression of the intestinal stem cell (ISC) marker OLFM4 in human IECs. In the present study, we investigated the gene regulation and function of OLFM4 in human IEC lines. We confirmed that TNF-α and Notch synergistically upregulate the mRNA expression of OLFM4. Luciferase reporter assay showed that OLFM4 transcription is regulated by the synergy of TNF-α and Notch. At the protein level, synergy between TNF-α and Notch promoted cytoplasmic accumulation of OLFM4, which has potential anti-apoptotic properties in human IECs. Analysis of patient-derived tissues and organoids consistently showed cytoplasmic accumulation of OLFM4 in response to NF-κB and Notch activation. Cytoplasmic accumulation of OLFM4 in human IECs is tightly regulated by Notch and TNF-α in synergy. Such cytoplasmic accumulation of OLFM4 may have a cell-protective role in the inflamed mucosa of patients with IBD.

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Notch and TNF-α signaling is important in IECs of patients with IBD.

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Notch and TNF-α signaling promotes the cytoplasmic accumulation of OLFM4.

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OLFM4 accumulation may have anti-apoptotic properties.

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OLFM4 could protect against mucosal inflammation in IBD.

A Novel PAK1-Notch1 Axis Regulates Crypt Homeostasis in Intestinal Inflammation

BACKGROUND & AIMS

p21-activated kinase-1 (PAK1) belongs to a family of serine-threonine kinases and contributes to cellular pathways such as nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), and Wingless-related integration site(Wnt)/β-catenin, all of which are involved in intestinal homeostasis. Overexpression of PAK1 is linked to inflammatory bowel disease as well as colitis-associated cancer (CAC), and similarly was observed in interleukin (IL)10 knockout (KO) mice, a model of colitis and CAC. Here, we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL10 KO mice.

METHODS

IL10/PAK1 double-knockout (DKO) mice were generated and development of colitis and CAC was analyzed. Large intestines were measured and prepared for histology or RNA isolation. Swiss rolls were stained with H&E and periodic acid-Schiff. Co-immunoprecipitation and immunofluorescence were performed using intestinal organoids, SW480, and normal human colon epithelial cells 1CT.

RESULTS

When compared with IL10 KO mice, DKOs showed longer colons and prolonged crypts, despite having higher inflammation and numbers of dysplasia. Crypt hyperproliferation was associated with Notch1 activation and diminished crypt differentiation, indicated by a reduction of goblet cells. Gene expression analysis indicated up-regulation of the Notch1 target hairy and enhancer of split-1 and the stem cell receptor leucin-rich repeat-containing G-protein-coupled receptor 5 in DKO mice. Interestingly, the stem cell marker olfactomedin-4 was present in colonic tissue. Increased β-catenin messenger RNA and cytoplasmic accumulation indicated aberrant Wnt signaling. Co-localization and direct interaction of Notch1 and PAK1 was found in colon epithelial cells. Notch1 activation abrogated this effect whereas silencing of PAK1 led to Notch1 activation.

CONCLUSIONS

PAK1 contributes to the regulation of crypt homeostasis under inflammatory conditions by controlling Notch1. This identifies a novel PAK1-Notch1 axis in intestinal pathophysiology of inflammatory bowel disease and CAC.

Altered DNA methylation is associated with aberrant stemness gene expression in early‑stage HNSCC

Head and neck squamous cell carcinoma (HNSCC) is characterized by morphological and functional cellular heterogeneity, which are properties of progenitor cells, as opposed to cell alterations caused by accidental expression of stem cell‑related molecules. The expression levels of stemness molecules and their distribution in HNSCC are unclear. As regards sporadic cellular heterogeneity, methylation is an important factor for transcriptional regulation in tumors. Integrative screening analysis of mRNA expression and altered methylation status was performed with original microarrays in 12 tumor and non‑tumor pairs of oral squamous cell carcinoma (SCC) cases. From this data set, genes regulated via aberrant DNA methylation and classified proteins were validated by function clustering. Olfactomedin 4 (OLFM4), known as an intestinal stemness molecule and cell‑cell adhesion factor, was found to be highly expressed in tumors, with an mRNA expression ratio [tumor/normal (T/N)] of 40.7686 and low methylation (‑18.02%) in the promoter region. In addition, the OLFM4 expression levels increased following treatment with the demethylating agent 5‑azacytidine in two HNSCC cell lines. Furthermore, the expression levels of OLFM4 in 59 cases of early‑stage tongue SCC were analyzed using immunohistochemistry to examine protein expression corresponding to the histopathological definition of tumors and to evaluate prognosis. The aberrant stemness gene expression caused by altered DNA methylation appeared to regulate early‑stage HNSCC characteristics. The results of the present study indicated a correlation between OLFM4 expression and promoter methylation, and suggest that it plays an important role in tumor cell heterogeneity in HNSCC.

Quantitative Proteomic Analysis Reveals the Deregulation of Nicotinamide Adenine Dinucleotide Metabolism and CD38 in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) has become a major health challenge worldwide. However, the precise etiological and pathophysiological factors involved in IBD remain unclear. Proteomics can be used for large-scale protein identification analysis. In the current study, using tandem mass tag- (TMT-) based shotgun proteomics, proteomic differences between intestinal tissue from health controls, patients with Crohn's disease (CD), and patients with ulcerative colitis (UC) were compared. Proteins with fold change >2 or <0.5 and P value < 0.05 between groups were considered differentially expressed. ProteinAtlas was used to analyze the tissue specificity of differentially expressed proteins (DEPs). Reactome pathway analysis was applied to cluster functional pathways. A total of 4786 proteins were identified, with 59 proteins showing higher levels and 43 showing lower levels in patients with IBD than in controls. Seventeen proteins, including angiotensin converting enzyme 2 (ACE2) and angiotensin converting enzyme 1 (ACE), showed higher levels in CD than in UC. Several novel proteins such as CD38, chitinase 3-like 1 (CHI3L1), olfactomedin 4 (OLFM4), and intelectin 1 were screened out between patients with IBD and controls. When proteins with fold change >1.2 or <0.84 and P value < 0.05 between groups were considered differentially expressed, the expression of 10 proteins, including CD38, involved in the nicotinamide adenine dinucleotide (NAD) metabolism and signaling pathway showed significant changes in IBD. Using the NCBI GEO database, we confirmed increased CD38 mRNA expression in patients with UC and in mouse colitis models. Protein CD38 expression was higher in CD and UC than in normal controls. CD38 expression was higher in inflamed tissues than in noninflamed tissues, and CD38 was located in F4/80-positive cells. Our study may provide novel insights into the molecular pathogenesis of IBD. Further studies are required on the role of NAD metabolism and CD38 in intestinal inflammation.

Major microbiota dysbiosis in severe obesity: fate after bariatric surgery

OBJECTIVES

Decreased gut microbial gene richness (MGR) and compositional changes are associated with adverse metabolism in overweight or moderate obesity, but lack characterisation in severe obesity. Bariatric surgery (BS) improves metabolism and inflammation in severe obesity and is associated with gut microbiota modifications. Here, we characterised severe obesity-associated dysbiosis (ie, MGR, microbiota composition and functional characteristics) and assessed whether BS would rescue these changes.

DESIGN

Sixty-one severely obese subjects, candidates for adjustable gastric banding (AGB, n=20) or Roux-en-Y-gastric bypass (RYGB, n=41), were enrolled. Twenty-four subjects were followed at 1, 3 and 12 months post-BS. Gut microbiota and serum metabolome were analysed using shotgun metagenomics and liquid chromatography mass spectrometry (LC-MS). Confirmation groups were included.

RESULTS

Low gene richness (LGC) was present in 75% of patients and correlated with increased trunk-fat mass and comorbidities (type 2 diabetes, hypertension and severity). Seventy-eight metagenomic species were altered with LGC, among which 50% were associated with adverse body composition and metabolic phenotypes. Nine serum metabolites (including glutarate, 3-methoxyphenylacetic acid and L-histidine) and functional modules containing protein families involved in their metabolism were strongly associated with low MGR. BS increased MGR 1 year postsurgery, but most RYGB patients remained with low MGR 1 year post-BS, despite greater metabolic improvement than AGB patients.

CONCLUSIONS

We identified major gut microbiota alterations in severe obesity, which include decreased MGR and related functional pathways linked with metabolic deteriorations. The lack of full rescue post-BS calls for additional strategies to improve the gut microbiota ecosystem and microbiome-host interactions in severe obesity.

TRIAL REGISTRATION NUMBER

NCT01454232.

Genome-wide DNA Methylation in Treatment-naïve Ulcerative Colitis

BACKGROUND AND AIMS

The aim of this study was to investigate the genome-wide DNA methylation status in treatment-naïve ulcerative colitis [UC], and to explore the relationship between DNA methylation patterns and gene expression levels in tissue biopsies from a well-stratified treatment-naïve UC patient group.

METHODS

Mucosal biopsies from treatment-naïve patients [n = 10], and a healthy control group [n = 11] underwent genome-wide DNA bisulfite sequencing. Principal component analysis [PCA] and diverse statistical methods were applied to obtain a dataset of differentially methylated genes. DNA methylation annotation was investigated using the UCSC Genome Browser. Gene set enrichments were obtained using the Kyoto Encyclopaedia of Genes and Genomes [KEGG] and PANTHER.

RESULTS

Of all significantly differentially expressed genes [DEGs], 25% correlated with DNA methylation patterns; 30% of these genes were methylated at CpG sites near their transcription start site [TSS]. Hyper-methylation was observed for genes involved in homeostasis and defence, whereas hypo-methylation was observed for genes playing a role in immune response [i.e. chemokines and interleukins]. Of the differentially DNA methylated genes, 25 were identified as inflammatory bowel disease [IBD] susceptibility genes. Four genes [DEFFA6, REG1B, BTNL3, OLFM4] showed DNA methylation in the absence of known CpG islands.

CONCLUSIONS

Genome-wide DNA methylation analysis revealed distinctive functional patterns for hyper-and hypo-methylation in treatment-naïve UC. These distinct patterns could be of importance in the development and pathogenesis of UC. Further investigation of DNA methylation patterns may be useful in the development of the targeting of epigenetic processes, and may allow new treatment and target strategies for UC patients.

Olfactomedin-4 in digestive diseases: A mini-review

Olfactomedin-4 (OLFM4, GW112, hGC-1) is a glycoprotein belonging to the olfactomedin family. The expression of OLFM4 is strong in the small intestine, colon and prostate, and moderate in the stomach and bone marrow. Previous studies have revealed that OLFM4 is closely associated with many digestive diseases. Up-regulation of OLFM4 has been detected in the Helicobacter pylori (H. pylori)-infected gastric mucosa, inflammatory bowel disease tissue and gastrointestinal malignancies, including gastric cancer, colorectal cancer, pancreatic cancer and gallbladder cancer. Down-regulation of OLFM4 has also been detected in some cases, such as in poorly differentiated, advanced-stage and metastatic tumors. Studies using OLFM4-deficient mouse models have revealed that OLFM4 acts as a negative regulator of H. pylori-specific immune responses and plays an important role in mucosal defense in inflammatory bowel disease. Patients with OLFM4-positive gastric cancer or colorectal cancer have a better survival rate than OLFM4-negative patients. However, the prognosis is worse in pancreatic cancer patients with high levels of expression of OLFM4. The NF-κB, Notch and Wnt signaling pathways are involved in the regulation of OLFM4 expression in digestive diseases, and its role in pathogenesis is associated with anti-inflammation, apoptosis, cell adhesion and proliferation. OLFM4 may serve as a potential specific diagnostic marker and a therapeutic target in digestive diseases. Further studies are required to explore the clinical value of OLFM4.

Single cell analysis of Crohn's disease patient-derived small intestinal organoids reveals disease activity-dependent modification of stem cell properties

BACKGROUND

Intestinal stem cells (ISCs) play indispensable roles in the maintenance of homeostasis, and also in the regeneration of the damaged intestinal epithelia. However, whether the inflammatory environment of Crohn's disease (CD) affects properties of resident small intestinal stem cells remain uncertain.

METHODS

CD patient-derived small intestinal organoids were established from enteroscopic biopsy specimens taken from active lesions (aCD-SIO), or from mucosa under remission (rCD-SIO). Expression of ISC-marker genes in those organoids was examined by immunohistochemistry, and also by microfluid-based single-cell multiplex gene expression analysis. The ISC-specific function of organoid cells was evaluated using a single-cell organoid reformation assay.

RESULTS

ISC-marker genes, OLFM4 and SLC12A2, were expressed by an increased number of small intestinal epithelial cells in the active lesion of CD. aCD-SIOs, rCD-SIOs or those of non-IBD controls (NI-SIOs) were successfully established from 9 patients. Immunohistochemistry showed a comparable level of OLFM4 and SLC12A2 expression in all organoids. Single-cell gene expression data of 12 ISC-markers were acquired from a total of 1215 cells. t-distributed stochastic neighbor embedding analysis identified clusters of candidate ISCs, and also revealed a distinct expression pattern of SMOC2 and LGR5 in ISC-cluster classified cells derived from aCD-SIOs. Single-cell organoid reformation assays showed significantly higher reformation efficiency by the cells of the aCD-SIOs compared with that of cells from NI-SIOs.

CONCLUSIONS

aCD-SIOs harbor ISCs with modified marker expression profiles, and also with high organoid reformation ability. Results suggest modification of small intestinal stem cell properties by unidentified factors in the inflammatory environment of CD.

c-Jun N-terminal kinase 2 promotes enterocyte survival and goblet cell differentiation in the inflamed intestine

c-Jun N-terminal kinases (JNKs) contribute to immune signaling but their functional role during intestinal mucosal inflammation has remained ill defined. Using genetic mouse models, we characterized the role of JNK1 and JNK2 during homeostasis and acute colitis. Epithelial apoptosis, regeneration, differentiation, and barrier function were analyzed in intestinal epithelium-specific (ΔIEC) or complete JNK1 and bone marrow chimeric or complete JNK2 deficient mice as well as double-knockout animals (JNK1^ΔIECJNK2^-/-) during homeostasis and acute dextran sulfate sodium (DSS)-induced colitis. Results were confirmed using human HT-29 cells and wild-type or JNK2-deficient mouse intestinal organoid cultures. We show that nonhematopoietic JNK2 but not JNK1 expression confers protection from DSS-induced intestinal inflammation reducing epithelial barrier dysfunction and enterocyte apoptosis. JNK2 additionally enhanced Atonal homolog 1 expression, goblet cell and enteroendocrine cell differentiation, and mucus production under inflammatory conditions. Our results identify a protective role of epithelial JNK2 signaling to maintain mucosal barrier function, epithelial cell integrity, and mucus layer production in the event of inflammatory tissue damage.

NLRC3 regulates cellular proliferation and apoptosis to attenuate the development of colorectal cancer

Nucleotide-binding domain, leucine-rich-repeat-containing proteins (NLRs) are intracellular innate immune sensors of pathogen-associated and damage-associated molecular patterns. NLRs regulate diverse biologic processes such as inflammatory responses, cell proliferation and death, and gut microbiota to attenuate tumorigenesis. In a recent publication in Nature, we identified NLRC3 as a negative regulator of PI3K-mTOR signaling and characterized its potential tumor suppressor function. Enterocytes lacking NLRC3 cannot control cellular proliferation because they are unable to suppress activation of PI3K-mTOR signaling pathways. In this Extra-View, we explore possible mechanisms through which NLRC3 regulates cellular proliferation and cell death. Besides interacting with PI3K, NLRC3 associates with TRAF6 and mTOR, confirming our recent finding that NLRC3 negatively regulates the PI3K-mTOR axis. Herein, we show that NLRC3 suppresses c-Myc expression and activation of PI3K-AKT targets FoxO3a and FoxO1 in the colon of Nlrc3^-/- mice, suggesting that additional signaling pathways contribute to increased cellular proliferation. Moreover, NLRC3 suppresses colorectal tumorigenesis by promoting cellular apoptosis. Genes encoding intestinal stem cell markers BMI1 and OLFM4 are upregulated in the colon of Nlrc3^-/- mice. Herein, we discuss recent findings and explore mechanisms through which NLRC3 regulates PI3K-mTOR signaling. Our studies highlight the therapeutic potential of modulating NLRC3 to prevent and treat cancer.

Nutrient sensing by absorptive and secretory progenies of small intestinal stem cells

Nutrient sensing triggers responses by the gut-brain axis modulating hormone release, feeding behavior and metabolism that become dysregulated in metabolic syndrome and some cancers. Except for absorptive enterocytes and secretory enteroendocrine cells, the ability of many intestinal cell types to sense nutrients is still unknown; hence we hypothesized that progenitor stem cells (intestinal stem cells, ISC) possess nutrient sensing ability inherited by progenies during differentiation. We directed via modulators of Wnt and Notch signaling differentiation of precursor mouse intestinal crypts into specialized organoids each containing ISC, enterocyte, goblet, or Paneth cells at relative proportions much higher than in situ as determined by mRNA expression and immunocytochemistry of cell type biomarkers. We identified nutrient sensing cell type(s) by increased expression of fructolytic genes in response to a fructose challenge. Organoids comprised primarily of enterocytes, Paneth, or goblet, but not ISC, cells responded specifically to fructose without affecting nonfructolytic genes. Sensing was independent of Wnt and Notch modulators and of glucose concentrations in the medium but required fructose absorption and metabolism. More mature enterocyte- and goblet-enriched organoids exhibited stronger fructose responses. Remarkably, enterocyte organoids, upon forced dedifferentiation to reacquire ISC characteristics, exhibited a markedly extended lifespan and retained fructose sensing ability, mimicking responses of some dedifferentiated cancer cells. Using an innovative approach, we discovered that nutrient sensing is likely repressed in progenitor ISCs then irreversibly derepressed during specification into sensing-competent absorptive or secretory lineages, the surprising capacity of Paneth and goblet cells to detect fructose, and the important role of differentiation in modulating nutrient sensing.NEW & NOTEWORTHY Small intestinal stem cells differentiate into several cell types transiently populating the villi. We used specialized organoid cultures each comprised of a single cell type to demonstrate that 1) differentiation seems required for nutrient sensing, 2) secretory goblet and Paneth cells along with enterocytes sense fructose, suggesting that sensing is acquired after differentiation is triggered but before divergence between absorptive and secretory lineages, and 3) forcibly dedifferentiated enterocytes exhibit fructose sensing and lifespan extension.

Olfactomedin-4 Is a Candidate Marker for a Pathogenic Neutrophil Subset in Septic Shock

OBJECTIVES

Heterogeneity in sepsis-related pathobiology presents a significant challenge. Resolving this heterogeneity presents an opportunity to understand pathobiology and improve patient care. Olfactomedin-4 is a neutrophil subset marker and may contribute to sepsis heterogeneity. Our objective was to evaluate the expression of olfactomedin-4 and characterize neutrophil heterogeneity in children with septic shock.

DESIGN

Single-center, prospective cohort, as well as secondary analysis of existing transcriptomic and proteomic databases.

SETTING

Tertiary care PICU.

PATIENTS

Patients from 5 days to 18 years old with septic shock were enrolled. Data collected included the expression of olfactomedin-4 messenger RNA, serum protein concentrations, and percentage of neutrophils that express olfactomedin-4.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Secondary analysis of existing transcriptomic data demonstrated that olfactomedin-4 is the most highly expressed gene in nonsurvivors of pediatric septic shock, compared with survivors. Secondary analysis of an existing proteomic database corroborated these observations. In a prospectively enrolled cohort, we quantified the percentage of olfactomedin-4+ neutrophils in patients with septic shock. Patients with a complicated course, defined as greater than or equal to two organ failures at day 7 of septic shock or 28-day mortality, had a higher percentage of olfactomedin-4+ neutrophils, compared with those without a complicated course. By logistic regression, the percentage of olfactomedin-4+ neutrophils was independently associated with increased risk of a complicated course (odds ratio, 1.09; 95% CI, 1.01-1.17; p = 0.024).

CONCLUSIONS

Olfactomedin-4 identifies a subpopulation of neutrophils in patients with septic shock, and those with a high percentage of olfactomedin-4+ neutrophils are at higher risk for greater organ failure burden and death. Olfactomedin-4 might serve as a marker of a pathogenic neutrophil subset in patients with septic shock.

Transcriptome analysis illuminates the nature of the intracellular interaction in a vertebrate-algal symbiosis

During embryonic development, cells of the green alga Oophila amblystomatis enter cells of the salamander Ambystoma maculatum forming an endosymbiosis. Here, using de novo dual-RNA seq, we compared the host salamander cells that harbored intracellular algae to those without algae and the algae inside the animal cells to those in the egg capsule. This two-by-two-way analysis revealed that intracellular algae exhibit hallmarks of cellular stress and undergo a striking metabolic shift from oxidative metabolism to fermentation. Culturing experiments with the alga showed that host glutamine may be utilized by the algal endosymbiont as a primary nitrogen source. Transcriptional changes in salamander cells suggest an innate immune response to the alga, with potential attenuation of NF-κB, and metabolic alterations indicative of modulation of insulin sensitivity. In stark contrast to its algal endosymbiont, the salamander cells did not exhibit major stress responses, suggesting that the host cell experience is neutral or beneficial.

Embryonic cholecystitis and defective gallbladder contraction in the Sox17-haploinsufficient mouse model of biliary atresia

The gallbladder excretes cytotoxic bile acids into the duodenum through the cystic duct and common bile duct system. Sox17 haploinsufficiency causes biliary atresia-like phenotypes and hepatitis in late organogenesis mouse embryos, but the molecular and cellular mechanisms underlying this remain unclear. In this study, transcriptomic analyses revealed the early onset of cholecystitis in Sox17^+/- embryos, together with the appearance of ectopic cystic duct-like epithelia in their gallbladders. The embryonic hepatitis showed positive correlations with the severity of cholecystitis in individual Sox17^+/- embryos. Embryonic hepatitis could be induced by conditional deletion of Sox17 in the primordial gallbladder epithelia but not in fetal liver hepatoblasts. The Sox17^+/- gallbladder also showed a drastic reduction in sonic hedgehog expression, leading to aberrant smooth muscle formation and defective contraction of the fetal gallbladder. The defective gallbladder contraction positively correlated with the severity of embryonic hepatitis in Sox17^+/- embryos, suggesting a potential contribution of embryonic cholecystitis and fetal gallbladder contraction in the early pathogenesis of congenital biliary atresia.

Olfactomedin 4 expression and functions in innate immunity, inflammation, and cancer

Olfactomedin 4 (OLFM4) is an olfactomedin domain-containing glycoprotein. Multiple signaling pathways and factors, including NF-κB, Wnt, Notch, PU.1, retinoic acids, estrogen receptor, and miR-486, regulate its expression. OLFM4 interacts with several other proteins, such as gene associated with retinoic-interferon-induced mortality 19 (GRIM-19), cadherins, lectins, nucleotide oligomerization domain-1 (NOD1) and nucleotide oligomerization domain-2 (NOD2), and cathepsins C and D, known to regulate important cellular functions. Recent investigations using Olfm4-deficient mouse models have provided important clues about its in vivo biological functions. Olfm4 inhibited Helicobacter pylori-induced NF-κB pathway activity and inflammation and facilitated H. pylori colonization in the mouse stomach. Olfm4-deficient mice exhibited enhanced immunity against Escherichia coli and Staphylococcus aureus infection. Olfm4 deletion in a chronic granulomatous disease mouse model rescued them from S. aureus infection. Olfm4 deletion in mice treated with azoxymethane/dextran sodium sulfate led to robust intestinal inflammation and intestinal crypt hyperplasia. Olfm4 deletion in Apc (Min/+) mice promoted intestinal polyp formation as well as adenocarcinoma development in the distal colon. Further, Olfm4-deficient mice spontaneously developed prostatic epithelial lesions as they age. OLFM4 expression is correlated with cancer differentiation, stage, metastasis, and prognosis in a variety of cancers, suggesting its potential clinical value as an early-stage cancer marker or a therapeutic target. Collectively, these data suggest that OLFM4 plays important roles in innate immunity against bacterial infection, gastrointestinal inflammation, and cancer. In this review, we have summarized OLFM4's initial characterization, expression, regulation, protein interactions, and biological functions.

The clinical significance and biological function of olfactomedin 4 in triple negative breast cancer

Olfactomedin 4 abnormal expression has been observed in several types of human cancer, but the status of olfactomedin 4 in triple negative breast cancer is still unknown. The aim of our study is to explore the clinical significance and biological function of olfactomedin 4 in triple negative breast cancer. The mRNA and protein expression of olfactomedin 4 in triple negative breast cancer tissues and cell lines was detected, and the correlation between olfactomedin 4 expression and clinicopathological factors was analyzed by immunohistochemistry. The biological function of olfactomedin 4 on tumor-metastasis was explored by Transwell migration assay and invasion assay in vitro. In our results, olfactomedin 4 mRNA and protein expression is decreased in triple-negative breast cancer tissues and cell lines. Olfactomedin 4 protein low-expression associated with lymph node metastasis, distant metastasis, clinical stage and poor prognosis of triple-negative breast cancer patients. Up-regulation of olfactomedin 4 suppresseed triple-negative breast cancer cells migration and invasion, and reduced cell metastasis-associated protein MMP 9 expression. In conclusion, olfactomedin 4 is a novel biomarker of triple-negative breast cancer for predicting prognosis and developing targeted molecular therapies.

A Review of Research Conducted with Probiotic E. coli Marketed as Symbioflor

This review article summarizes the scientific literature that is currently available about a probiotic E. coli that is known under the name Symbioflor E. coli. The probiotic is marketed for human use and has been subjected to over 20 years of scientific research. As is presented here, the available literature not only contains multiple works to investigate and analyse the probiotic activity of this E. coli, but also describes a variety of other research experiments, dealing with a surprising and interesting range of subjects. By compiling all these works into one review article, more insights into this interesting probiotic E. coli were obtained.

Olfactomedin 4 deletion induces colon adenocarcinoma in ApcMin/+ mice

Colon carcinogenesis is a multiple-step process involving the accumulation of a series of genetic and epigenetic alterations. The most commonly initiating event of intestinal carcinogenesis is mutation of the adenomatous polyposis coli (APC) gene, which leads to activation of the Wnt/β-catenin pathway. Olfactomedin 4 (OLFM4) has emerged as an intestinal stem-cell marker, but its biological function in the intestine remains to be determined. Here we show that Olfm4 deletion induced colon adenocarcinoma in the distal colon of Apc^Min/+ mice. Mechanistically, we found that OLFM4 is a target gene of the Wnt/β-catenin pathway and can downregulate β-catenin signaling by competing with Wnt ligands for binding to Frizzled receptors, as well as by inhibition of the Akt-GSK-3β (Akt-glycogen synthase kinase-3β) pathway. We have shown that both Wnt and nuclear factor-κB (NF-κB) signaling were boosted in tumor tissues of Apc Olfm4 double-mutant mice. These data establish OLFM4 as a critical negative regulator of the Wnt/β-catenin and NF-κB pathways that inhibits colon-cancer development initiated by APC mutation. In addition, Olfm4 deletion significantly enhanced intestinal-crypt proliferation and inflammation induced by azoxymethane/dextran sodium sulfate. Thus, OLFM4 has an important role in the regulation of intestinal inflammation and tumorigenesis, and could be a potential therapeutic target for intestinal malignant tumors. Unlike the human colonic epithelium, the mouse colonic epithelium does not express OLFM4, but nevertheless, systemic OLFM4 deletion promotes colon tumorigenesis and that loss from mucosal neutrophils may have a role to play.

Plasma levels of OLFM4 in normals and patients with gastrointestinal cancer

Olfactomedin 4 (OLFM4) is a secreted glycoprotein predominantly expressed in bone marrow and gastrointestinal tissues. Aberrant expression of OLFM4 has been shown in several cancers. However, the clinical significance hereof is currently controversial. OLFM4 has been proposed as a candidate biomarker of gastrointestinal cancers. To address this, we developed monoclonal antibodies against synthetic peptides representing various segments of OLFM4. We examined expression of OLFM4 in epithelial cells by immunohistochemistry and found that OLFM4 is highly expressed in proliferating benign epithelial cells and in some carcinoma cells. We developed an Enzyme Linked Immunosorbent Assay for OLFM4 and investigated whether plasma levels of OLFM4 reflect colorectal malignancies, but were unable to see any such association. Instead, we observed two populations of individuals with respect to OLFM4 levels in plasma, the majority with OLFM4 in plasma between 0 and 0.1 μg/ml, mean 0.028 μg/ml while 10% of both normals and patients with cancers had OLFM4 between 4 and 60 μg/ml, mean 15 μg/ml. The levels were constant over time. The background for this high plasma level is not known, but must be taken into account if OLFM4 is used as biomarker for GI cancers.

Olfactomedin 4 Serves as a Marker for Disease Severity in Pediatric Respiratory Syncytial Virus (RSV) Infection

Background

Respiratory viral infections follow an unpredictable clinical course in young children ranging from a common cold to respiratory failure. The transition from mild to severe disease occurs rapidly and is difficult to predict. The pathophysiology underlying disease severity has remained elusive. There is an urgent need to better understand the immune response in this disease to come up with biomarkers that may aid clinical decision making.

Methods

In a prospective study, flow cytometric and genome-wide gene expression analyses were performed on blood samples of 26 children with a diagnosis of severe, moderate or mild Respiratory Syncytial Virus (RSV) infection. Differentially expressed genes were validated using Q-PCR in a second cohort of 80 children during three consecutive winter seasons. FACS analyses were also performed in the second cohort and on recovery samples of severe cases in the first cohort.

Results

Severe RSV infection was associated with a transient but marked decrease in CD4+ T, CD8+ T, and NK cells in peripheral blood. Gene expression analyses in both cohorts identified Olfactomedin4 (OLFM4) as a fully discriminative marker between children with mild and severe RSV infection, giving a PAM cross-validation error of 0%. Patients with an OLFM4 gene expression level above -7.5 were 6 times more likely to develop severe disease, after correction for age at hospitalization and gestational age.

Conclusion

By combining genome-wide expression profiling of blood cell subsets with clinically well-annotated samples, OLFM4 was identified as a biomarker for severity of pediatric RSV infection.

Molecular Details of Olfactomedin Domains Provide Pathway to Structure-Function Studies

Olfactomedin (OLF) domains are found within extracellular, multidomain proteins in numerous tissues of multicellular organisms. Even though these proteins have been implicated in human disorders ranging from cancers to attention deficit disorder to glaucoma, little is known about their structure(s) and function(s). Here we biophysically, biochemically, and structurally characterize OLF domains from H. sapiens olfactomedin-1 (npoh-OLF, also called noelin, pancortin, OLFM1, and hOlfA), and M. musculus gliomedin (glio-OLF, also called collomin, collmin, and CRG-L2), and compare them with available structures of myocilin (myoc-OLF) recently reported by us and R. norvegicus glio-OLF and M. musculus latrophilin-3 (lat3-OLF) by others. Although the five-bladed β-propeller architecture remains unchanged, numerous physicochemical characteristics differ among these OLF domains. First, npoh-OLF and glio-OLF exhibit prominent, yet distinct, positive surface charges and copurify with polynucleotides. Second, whereas npoh-OLF and myoc-OLF exhibit thermal stabilities typical of human proteins near 55°C, and most myoc-OLF variants are destabilized and highly prone to aggregation, glio-OLF is nearly 20°C more stable and significantly more resistant to chemical denaturation. Phylogenetically, glio-OLF is most similar to primitive OLFs, and structurally, glio-OLF is missing distinguishing features seen in OLFs such as the disulfide bond formed by N- and C- terminal cysteines, the sequestered Ca²⁺ ion within the propeller central hydrophilic cavity, and a key loop-stabilizing cation-π interaction on the top face of npoh-OLF and myoc-OLF. While deciphering the explicit biological functions, ligands, and binding partners for OLF domains will likely continue to be a challenging long-term experimental pursuit, we used structural insights gained here to generate a new antibody selective for myoc-OLF over npoh-OLF and glio-OLF as a first step in overcoming the impasse in detailed functional characterization of these biomedically important protein domains.

Expression of Wnt and Notch signaling pathways in inflammatory bowel disease treated with mesenchymal stem cell transplantation: evaluation in a rat model

INTRODUCTION

The purpose of this study was to investigate the expression of Wnt and Notch signaling pathway-related genes in inflammatory bowel disease (IBD) treated with mesenchymal stem cell transplantation (MSCT).

METHODS

TNBS (2,4,6-trinitrobenzene sulfonic acid) was used to establish IBD in a rat model. Mesenchymal stem cells (MSCs) were transplanted via tail vein transfusion. Saline water was used in a control group. The expression of Wnt and Notch main signaling molecules was screened by gene chips and verified by quantitative reverse transcription-polymerase chain reaction in the IBD rat model on day 14 and day 28 after transplantation.

RESULTS

The IBD rat models were successfully established and MSCs were transplanted into those models. Genome-wide expression profile chips identified a total of 388 differentially expressive genes, of which 191 were upregulated and 197 were downregulated in the MSC-transplanted group in comparison with the IBD control group. Real-time quantitative polymerase chain reaction results showed that the level of Olfm4 mRNA expression in the IBD group (2.54±0.20) was significantly increased compared with the MSCT group (1.39±0.54) and the normal group (1.62±0.25) (P <0.05). The Wnt3a mRNA was more highly expressed in IBD rats (2.92±0.94) and decreased in MSCT rats (0.17±0.63, P <0.05). The expression of GSK-3β mRNA was decreased in the setting of inflammation (0.65±0.04 versus 1.00±0.01 in normal group, P <0.05) but returned to normal levels after MSCT (0.81±0.17). The expression of β-catenin was observed to increase in IBD tissues (1.76±0.44) compared with normal tissues (1.00±0.01, P <0.05), but no difference was found in the MSCT group (1.12±0.36). Wnt11 declined at 14 days and returned to normal levels at 28 days in the IBD group; in comparison, a significantly lower expression was found in MSCT rats. There were no differences in the expression of Fzd3, c-myc, TCF4, and Wnt5a in inflammation, but all of those genes declined after MSCT treatment.

CONCLUSIONS

The canonical Wnt and Notch signaling pathways are activated in IBD and may be suppressed by stem cell transplantation to differentiate into intestinal epithelium after MSCT. Moreover, the non-canonical Wnt signaling may be inhibited by canonical Wnt signaling in the setting of inflammation and may also be suppressed by MSCT.

Structural basis for misfolding in myocilin-associated glaucoma

Olfactomedin (OLF) domain-containing proteins play roles in fundamental cellular processes and have been implicated in disorders ranging from glaucoma, cancers and inflammatory bowel disorder, to attention deficit disorder and childhood obesity. We solved crystal structures of the OLF domain of myocilin (myoc-OLF), the best studied such domain to date. Mutations in myoc-OLF are causative in the autosomal dominant inherited form of the prevalent ocular disorder glaucoma. The structures reveal a new addition to the small family of five-bladed β-propellers. Propellers are most well known for their ability to act as hubs for protein-protein interactions, a function that seems most likely for myoc-OLF, but they can also act as enzymes. A calcium ion, sodium ion and glycerol molecule were identified within a central hydrophilic cavity that is accessible via movements of surface loop residues. By mapping familial glaucoma-associated lesions onto the myoc-OLF structure, three regions sensitive to aggregation have been identified, with direct applicability to differentiating between neutral and disease-causing non-synonymous mutations documented in the human population worldwide. Evolutionary analysis mapped onto the myoc-OLF structure reveals conserved and divergent regions for possible overlapping and distinctive functional protein-protein or protein-ligand interactions across the broader OLF domain family. While deciphering the specific normal biological functions, ligands and binding partners for OLF domains will likely continue to be a challenging long-term experimental pursuit, atomic detail structural knowledge of myoc-OLF is a valuable guide for understanding the implications of glaucoma-associated mutations and will help focus future studies of this biomedically important domain family.