Cell Adhesion Molecule CD166/ALCAM Functions Within the Crypt to Orchestrate Murine Intestinal Stem Cell Homeostasis

Dual states of murine Bmi1-expressing intestinal stem cells drive epithelial development utilizing non-canonical Wnt signaling

Intestinal epithelial development and homeostasis critically rely upon balanced stem cell proliferation, involving slow-cycling/label-retaining and active-cycling/canonical Wnt-dependent intestinal stem cell (ISC) subtypes. ISC regulation during development remains poorly understood but has important implications for establishing key mechanisms governing tissue maintenance. Herein, we identify Bmi1+ cells as functional stem cells present in early murine intestinal development, prior to Lgr5-expressing ISCs. Lineage tracing and single-cell RNA sequencing identify that Bmi1+ ISCs can trace to Lgr5+ ISCs and other differentiated lineages. Initially highly proliferative, Bmi1+ ISCs transition to slow-cycling states as Lgr5+ ISCs emerge. Non-canonical Wnt signaling regulates the proliferative Bmi1+ cell state. These findings highlight the dynamic interplay between stem cell populations and the opposing Wnt pathways that govern proliferation-ultimately having implications for tissue development, homeostasis, regeneration, and tumorigenesis. Understanding these fundamental developmental mechanisms is critical for understanding adult intestinal maintenance.

AP-1B regulates interactions of epithelial cells and intraepithelial lymphocytes in the intestine

Intraepithelial lymphocytes (IELs) reside in the epithelial layer and protect against foreign pathogens, maintaining the epithelial barrier function in the intestine. Interactions between IEL and epithelial cells are required for IELs to function effectively; however, the underlying molecular machinery remains to be elucidated. In this study, we found that intestinal epithelium-specific deficiency of the clathrin adaptor protein (AP)-1B, which regulates basolateral protein sorting, led to a massive reduction in IELs. Quantitative proteomics demonstrated that dozens of proteins, including known IEL-interacting proteins (E-cadherin, butyrophilin-like 2, and plexin B2), were decreased in the basolateral membrane of AP-1B-deficient epithelial cells. Among these proteins, CD166 interacted with CD6 on the surface of induced IEL. CD166 knockdown, using shRNA in intestinal organoid cultures, significantly inhibited IEL recruitment to the epithelial layer. These findings highlight the essential role of AP-1B-mediated basolateral sorting in IEL maintenance and survival within the epithelial layer. This study reveals a novel function of AP-1B in the intestinal immune system.

Essential oils improve nursery pigs' performance and appetite via modulation of intestinal health and microbiota

Optimal intestinal health and functionality are essential for animal health and performance, and simultaneously intestinal nutrient transporters and intestinal peptides are also involved in appetite and feed intake control mechanisms. Given the potential of essential oil (EO) in improving animal performance and improving feed palatability, we hypothesized that dietary supplementation of cinnamaldehyde and carvacrol could improve performance and appetite of nursery pigs by modulating intestinal health and microbiota. Cinnamaldehyde (100 mg/kg), carvacrol (100 mg/kg), and their mixtures (including 50 mg/kg cinnamaldehyde and 50 mg/kg carvacrol) were supplemented into the diets of 240 nursery pigs for 42 d, and data related to performance were measured. Thereafter, the influence of EO on intestinal health, appetite and gut microbiota and their correlations were explored. EO supplementation increased (P < 0.05) the body weight, average daily gain (ADG) and average daily feed intake (ADFI) of piglets, and reduced (P < 0.05) diarrhea rates in nursery pigs. Furthermore, EO increased (P < 0.05) the intestinal absorption area and the abundance of tight junction proteins, and decreased (P < 0.05) intestinal permeability and local inflammation. In terms of intestinal development and the mucus barrier, EO promoted intestinal development and increased (P < 0.05) the number of goblet cells. Additionally, we found that piglets in the EO-supplemented group had upregulated (P < 0.05) levels of transporters and digestive enzymes in the intestine, which were significantly associated with daily gain and feed utilization. In addition, EO supplementation somewhat improved appetite in nursery pigs, increased the diversity of the gut microbiome and the abundance of beneficial bacteria, and there was a correlation between altered bacterial structure and appetite-related hormones. These findings indicate that EO is effective in promoting growth performance and nutrient absorption as well as in regulating appetite by improving intestinal health and bacterial structure.

Markers of dental pulp stem cells in in vivo developmental context

Teeth and their associated tissues contain several populations of mesenchymal stem cells, one of which is represented by dental pulp stem cells (DPSCs). These cells have mainly been characterised in vitro and numerous positive and negati ve markers for these cells have been suggested. To investigate the presence and localization of these molecules during development, forming dental pulp was examined using the mouse first mandibular molar as a model. The stages corresponding to postnatal (P) days 0, 7, 14, and 21 were investigated. The expression was monitored using customised PCR Arrays. Additionally, in situ localization of the key trio of markers (Cd73, Cd90, Cd105 coded by genes Nt5e, Thy1, Eng) was performed at prenatal and postnatal stages using immunohistochemistry. The expression panel of 24 genes assigned as in vitro markers of DPSCs or mesenchymal stem cells (MSCs) revealed their developmental dynamics during formation of dental pulp mesenchyme. Among the positive markers, Vcam1, Fgf2, Nes were identified as increasing and Cd44, Cd59b, Mcam, Alcam as decreasing between perinatal vs. postnatal stages towards adulthood. Within the panel of negative DPSC markers, Cd14, Itgb2, Ptprc displayed increased and Cd24a decreased levels at later stages of pulp formation. Within the key trio of markers, Nt5e did not show any significant expression difference within the investigated period. Thy1 displayed a strong decrease between P0 and P7 while Eng increased between these stages. In situ localization of Cd73, Cd90 and Cd105 showed them overlap in differentiated odontoblasts and in the sub-odontoblastic layer that is speculated to host odontoblast progenitors. The highly prevalent expression of particularly Cd73 and Cd90 opens the question of potential multiple functions of these molecules. The results from this study add to the in vitro based knowledge by showing dynamics in the expression of DPSC/MSC markers during dental pulp formation in an in vivo context and thus with respect to the natural environment important for commitment of stem cells.

Friend or Foe - Tc17 cell generation and current evidence for their importance in human disease

The term Tc17 cells refers to interleukin 17 (IL-17)-producing CD8+ T cells. While IL-17 is an important mediator of mucosal defense, it is also centrally involved in driving the inflammatory response in immune-mediated diseases, such as psoriasis, multiple sclerosis, and inflammatory bowel disease. In this review, we aim to gather the current knowledge on the phenotypic and transcriptional profile, the in vitro and in vivo generation of Tc17 cells, and the evidence pointing towards a relevant role of Tc17 cells in human diseases such as infectious diseases, cancer, and immune-mediated diseases.

Optimization and Characterization of Novel ALCAM-Targeting Antibody Fragments for Transepithelial Delivery

Activated leukocyte cell adhesion molecule (ALCAM) is a cell adhesion molecule that supports T cell activation, leukocyte migration, and (lymph)angiogenesis and has been shown to contribute to the pathology of various immune-mediated disorders, including asthma and corneal graft rejection. In contrast to monoclonal antibodies (mAbs) targeting ALCAM's T cell expressed binding partner CD6, no ALCAM-targeting mAbs have thus far entered clinical development. This is likely linked with the broad expression of ALCAM on many different cell types, which increases the risk of eliciting unwanted treatment-induced side effects upon systemic mAb application. Targeting ALCAM in surface-exposed tissues, such as the lungs or the cornea, by a topical application could circumvent this issue. Here, we report the development of various stability- and affinity-improved anti-ALCAM mAb fragments with cross-species reactivity towards mouse, rat, monkey, and human ALCAM. Fragments generated in either mono- or bivalent formats potently blocked ALCAM-CD6 interactions in a competition ELISA, but only bivalent fragments efficiently inhibited ALCAM-ALCAM interactions in a leukocyte transmigration assay. The different fragments displayed a clear size-dependence in their ability to penetrate the human corneal epithelium. Furthermore, intranasal delivery of anti-ALCAM fragments reduced leukocyte infiltration in a mouse model of asthma, confirming ALCAM as a target for topical application in the lungs.

Reduced adhesion of aged intestinal stem cells contributes to an accelerated clonal drift

Analysis of clonal dynamics of intestinal stem cells supports an accelerated clonal drift upon aging, likely because of reduced adhesion of aged ISCs because of reduced canonical Wnt signaling.

Upon aging, the function of the intestinal epithelium declines with a concomitant increase in aging-related diseases. ISCs play an important role in this process. It is known that ISC clonal dynamics follow a neutral drift model. However, it is not clear whether the drift model is still valid in aged ISCs. Tracking of clonal dynamics by clonal tracing revealed that aged crypts drift into monoclonality substantially faster than young ones. However, ISC tracing experiments, in vivo and ex vivo, implied a similar clonal expansion ability of both young and aged ISCs. Single-cell RNA sequencing for 1,920 high Lgr5 ISCs from young and aged mice revealed increased heterogeneity among subgroups of aged ISCs. Genes associated with cell adhesion were down-regulated in aged ISCs. ISCs of aged mice indeed show weaker adhesion to the matrix. Simulations applying a single cell–based model of the small intestinal crypt demonstrated an accelerated clonal drift at reduced adhesion strength, implying a central role for reduced adhesion for affecting clonal dynamics upon aging.

Identification, Characterization, and Transcriptional Reprogramming of Epithelial Stem Cells and Intestinal Enteroids in Simian Immunodeficiency Virus Infected Rhesus Macaques

Epithelial cell injury and impaired epithelial regeneration are considered key features in HIV pathogenesis and contribute to HIV-induced generalized immune activation. Understanding the molecular mechanisms underlying the disrupted epithelial regeneration might provide an alternative approach for the treatment of HIV-mediated enteropathy and immune activation. We have observed a significant increased presence of α defensin5+ (HD5) Paneth cells and proliferating Ki67+ epithelial cells as well as decreased expression of E-cadherin expression in epithelial cells during SIV infection. SIV infection did not significantly influence the frequency of LGR5+ stem cells, but the frequency of HD5+ cells was significantly higher compared to uninfected controls in jejunum. Our global transcriptomics analysis of enteroids provided novel information about highly significant changes in several important pathways like metabolic, TCA cycle, and oxidative phosphorylation, where the majority of the differentially expressed genes were downregulated in enteroids grown from chronically SIV-infected macaques compared to the SIV-uninfected controls. Despite the lack of significant reduction in LGR5+ stem cell population, the dysregulation of several intestinal stem cell niche factors including Notch, mTOR, AMPK and Wnt pathways as well as persistence of inflammatory cytokines and chemokines and loss of epithelial barrier function in enteroids further supports that SIV infection impacts on epithelial cell proliferation and intestinal homeostasis.

Multiomic analysis defines the first microRNA atlas across all small intestinal epithelial lineages and reveals novel markers of almost all major cell types

MicroRNA-mediated regulation is critical for the proper development and function of the small intestinal (SI) epithelium. However, it is not known which microRNAs are expressed in each of the cell types of the SI epithelium. To bridge this important knowledge gap, we performed comprehensive microRNA profiling in all major cell types of the mouse SI epithelium. We used flow cytometry and fluorescence-activated cell sorting with multiple reporter mouse models to isolate intestinal stem cells, enterocytes, goblet cells, Paneth cells, enteroendocrine cells, tuft cells, and secretory progenitors. We then subjected these cell populations to small RNA-sequencing. The resulting atlas revealed highly enriched microRNA markers for almost every major cell type (https://sethupathy-lab.shinyapps.io/SI_miRNA/). Several of these lineage-enriched microRNAs (LEMs) were observed to be embedded in annotated host genes. We used chromatin-run-on sequencing to determine which of these LEMs are likely cotranscribed with their host genes. We then performed single-cell RNA-sequencing to define the cell type specificity of the host genes and embedded LEMs. We observed that the two most enriched microRNAs in secretory progenitors are miR-1224 and miR-672, the latter of which we found is deleted in hominin species. Finally, using several in vivo models, we established that miR-152 is a Paneth cell-specific microRNA.NEW & NOTEWORTHY In this study, first, microRNA atlas (and searchable web server) across all major small intestinal epithelial cell types is presented. We have demonstrated microRNAs that uniquely mark several lineages, including enteroendocrine and tuft. Identification of a key marker of mouse secretory progenitor cells, miR-672, which we show is deleted in humans. We have used several in vivo models to establish miR-152 as a specific marker of Paneth cells, which are highly understudied in terms of microRNAs.

Relationship between CD 163 Tumor-Associated Macrophages and Colorectal-Cancer Stem Cell Markers

BACKGROUND: Colorectal-cancer stem cells (CR-CSCs) represent a specific subpopulation of colorectal cancer (CRC) cells, which are characterized by the expression of CD133 and CD166. Tumor-associated macrophages (TAMs), found near CSCs may represent polarized macrophages, which are characterized by CD163 expression. In most tumors, TAMs may promote aggressive tumor development, leading to poor prognoses. AIM: The aim of this study was to determine whether any association exists between CD163 expression in TAMs and CD133 and CD166 expression in CR-CSCs. METHODS: This study used a cross-sectional design that was conducted at the General Hospital and affiliates in Medan, from September 2018 to July 2019. CRC tissues were collected from colonoscopy biopsies and surgical resections performed on CRC patients, who fulfilled all necessary inclusion and exclusion criteria and provided informed consent. Subjects were divided into high- and low-CD163-level groups. We analyzed the expression levels of CD163, CD133, and CD166 using immunohistochemical (IHC) assays. RESULTS: A total of 118 CRC patients were enrolled in this study, of whom 58.5% were male. No significant differences in hemoglobin, leukocyte, or platelet levels were observed between high- and low-level CD163 expression. We didn’t find any significant association of CD163 TAM with CRC histological grade and TNM stagings. Significant associations were found between the CD 163 expression level and the CD133 expression level (p < 0.001) and between the CD 163 expression level and the CD166 expression level (p< 0.001). Increased TAM levels of CD163 was associated with 2.770-fold and 2.616-fold increased risks of elevated CD133 and CD166 levels, respectively. CONCLUSION: An association was found between the expression levels of CD163 in TAMs and the expression levels of CD133 and CD166 in CR-CSCs.

PGD2 and CRTH2 counteract Type 2 cytokine-elicited intestinal epithelial responses during helminth infection

Type 2 inflammation is associated with epithelial cell responses, including goblet cell hyperplasia, that promote worm expulsion during intestinal helminth infection. How these epithelial responses are regulated remains incompletely understood. Here, we show that mice deficient in the prostaglandin D2 (PGD2) receptor CRTH2 and mice with CRTH2 deficiency only in nonhematopoietic cells exhibited enhanced worm clearance and intestinal goblet cell hyperplasia following infection with the helminth Nippostrongylus brasiliensis. Small intestinal stem, goblet, and tuft cells expressed CRTH2. CRTH2-deficient small intestinal organoids showed enhanced budding and terminal differentiation to the goblet cell lineage. During helminth infection or in organoids, PGD2 and CRTH2 down-regulated intestinal epithelial Il13ra1 expression and reversed Type 2 cytokine-mediated suppression of epithelial cell proliferation and promotion of goblet cell accumulation. These data show that the PGD2-CRTH2 pathway negatively regulates the Type 2 cytokine-driven epithelial program, revealing a mechanism that can temper the highly inflammatory effects of the anti-helminth response.

The stromal vascular fraction mitigates radiation-induced gastrointestinal syndrome in mice

BACKGROUND

The intestine is particularly sensitive to moderate-high radiation dose and the development of gastrointestinal syndrome (GIS) leads to the rapid loss of intestinal mucosal integrity, resulting in bacterial infiltration, sepsis that comprise patient survival. There is an urgent need for effective and rapid therapeutic countermeasures. The stromal vascular fraction (SVF) derived from adipose tissue is an easily accessible source of cells with angiogenic, anti-inflammatory and regenerative properties. We studied the therapeutic impact of SVF and its action on the intestinal stem cell compartment.

METHODS

Mice exposed to the abdominal radiation (18 Gy) received a single intravenous injection of stromal vascular fraction (SVF) (2.5 × 106 cells), obtained by enzymatic digestion of inguinal fat tissue, on the day of irradiation. Mortality was evaluated as well as intestinal regeneration by histological analyses and absorption function.

RESULTS

The SVF treatment limited the weight loss of the mice and inhibited the intestinal permeability and mortality after abdominal irradiation. Histological analyses showed that SVF treatment stimulated the regeneration of the epithelium by promoting numerous enlarged hyperproliferative zones. SVF restored CD24+/lysozyme- and Paneth cell populations in the ISC compartment with the presence of Paneth Ki67+ cells. SVF has an anti-inflammatory effect by repressing pro-inflammatory cytokines, increasing M2 macrophages in the ileum and anti-inflammatory monocyte subtypes CD11b+Ly6clowCX3CR1high in the spleen.

CONCLUSIONS

Through the pleiotropic effects that contribute to limiting radiation-induced lethality, SVF opens up attractive prospects for the treatment of emergency GIS.

The Molecular Basis of Different Approaches for the Study of Cancer Stem Cells and the Advantages and Disadvantages of a Three-Dimensional Culture

Cancer stem cells (CSCs) are a rare tumor subpopulation with high differentiation, proliferative and tumorigenic potential compared to the remaining tumor population. CSCs were first discovered by Bonnet and Dick in 1997 in acute myeloid leukemia. The identification and isolation of these cells in this pioneering study were carried out through the flow cytometry, exploiting the presence of specific cell surface molecular markers (CD34⁺/CD38⁻). In the following years, different strategies and projects have been developed for the study of CSCs, which are basically divided into surface markers assays and functional assays; some of these techniques also allow working with a cellular model that better mimics the tumor architecture. The purpose of this mini review is to summarize and briefly describe all the current methods used for the identification, isolation and enrichment of CSCs, describing, where possible, the molecular basis, the advantages and disadvantages of each technique with a particular focus on those that offer a three-dimensional culture.

Flow cytometric characterization of cell surface markers to differentiate between fibroblasts and mesenchymal stem cells of different origin

Introduction

Identification and purification of mesenchymal stem cells (MSCs) expanded in culture for therapeutic use is crucial for improved yield and optimal results. Fibroblasts are the most common cell type in connective tissue and are commonly found as contaminants of MSC cultures, affecting cell yield and potentially causing tumour formation after cell transplantation. In the current study, we wished to identify cell surface markers that can differentiate MSCs of different origins from fibroblasts.

Material and methods

Mesenchymal stem cells were isolated from bone marrow, adipose tissue, Wharton's jelly, and placental tissue, and fibroblasts were isolated from foreskin (as a negative control) in order to examine the differences in the expression of a panel of 14 different cell surface markers using multiplex flow cytometry.

Results

Our results indicate that the following markers could be useful in differentiating between fibroblasts and MSCs derived from the following: adipose tissue - CD79a, CD105, CD106, CD146, and CD271; Wharton's jelly - CD14, CD56, and CD105; bone marrow - CD105, CD106, and CD146; and placental tissue - CD14, CD105, and CD146. Furthermore, we found that, contradictory to previous studies, CD26 is not fibroblast specific.

Conclusions

The results of our study indicate that cell surface markers may prove to be a useful tool in the discrimination between MSCs of different origins and fibroblasts, and thus may be used to authenticate the identity of the isolated cells.

Stem Cell Marker Expression in Early Stage Colorectal Cancer is Associated with Recurrent Intestinal Neoplasia

BACKGROUND

Colorectal cancer (CRC) ranks second in cancer deaths worldwide and presents multiple management challenges, one of which is identifying high risk stage II disease that may benefit from adjuvant therapy. Molecular biomarkers, such as ones that identify stem cell activity, could better stratify high-risk cohorts for additional treatment.

METHODS

To identify possible biomarkers of high-risk disease in early-stage CRC, a discovery set (n = 66) of advanced-stage tumors were immunostained with antibodies to stemness proteins (CD166, CD44, CD26, and LGR5) and then digitally analyzed. Using a second validation cohort (n = 54) of primary CRC tumors, we analyzed protein and gene expression of CD166 across disease stages, and extended our analyses to CD166-associated genes (LGR5, ASCL2, BMI1, POSTN, and VIM) by qRT-PCR.

RESULTS

Stage III and metastatic CRC tumors highly expressed stem cell-associated proteins, CD166, CD44, and LGR5. When evaluated across stages, CD166 protein expression was elevated in advanced-stage compared to early-stage tumors. Notably, a small subset of stage I and II cancers harbored elevated CD166 protein expression, which correlated with development of recurrent cancer or adenomatous polyps. Gene expression analyses of CD166-associated molecules revealed elevated ASCL2 in primary tumors from patients who recurred.

CONCLUSIONS

We identified a protein signature prognostic of aggressive disease in early stage CRC. Stem cell-associated protein and gene expression identified a subset of early-stage tumors associated with cancer recurrence and/or subsequent adenoma formation. Signatures for stemness offer promising fingerprints for stratifying early-stage patients at high risk of recurrence.

The Msi1-mTOR pathway drives the pathogenesis of mammary and extramammary Paget's disease

Mammary and extramammary Paget's Diseases (PD) are a malignant skin cancer characterized by the appearance of Paget cells. Although easily diagnosed, its pathogenesis remains unknown. Here, single-cell RNA-sequencing identified distinct cellular states, novel biomarkers, and signaling pathways - including mTOR, associated with extramammary PD. Interestingly, we identified MSI1 ectopic overexpression in basal epithelial cells of human PD skin, and show that Msi1 overexpression in the epidermal basal layer of mice phenocopies human PD at histopathological, single-cell and molecular levels. Using this mouse model, we identified novel biomarkers of Paget-like cells that translated to human Paget cells. Furthermore, single-cell trajectory, RNA velocity and lineage-tracing analyses revealed a putative keratinocyte-to-Paget-like cell conversion, supporting the in situ transformation theory of disease pathogenesis. Mechanistically, the Msi1-mTOR pathway drives keratinocyte-Paget-like cell conversion, and suppression of mTOR signaling with Rapamycin significantly rescued the Paget-like phenotype in Msi1-overexpressing transgenic mice. Topical Rapamycin treatment improved extramammary PD-associated symptoms in humans, suggesting mTOR inhibition as a novel therapeutic treatment in PD.

Zinc L-Aspartate enhances intestinal stem cell activity to protect the integrity of the intestinal mucosa against deoxynivalenol through activation of the Wnt/β-catenin signaling pathway

The micronutrient, zinc, plays a vital role in modulating cellular signaling recognition and enhancing intestinal barrier function. However, the precise mechanisms underlying the zinc regulation of intestinal stem cell (ISC) renewal and regeneration ability, which drive intestinal epithelial turnover to maintain the intestinal barrier, under physiological and pathological conditions are unknown. In this study, we used in vivo mouse plus ex vivo enteroid model to investigate thoroughly the protection efficacy of zinc L-aspartate (Zn-Asp) on intestinal mucosal integrity exposed to deoxynivalenol (DON). The results showed that 10 rather than 20 mg/kg body weight (BW) Zn-Asp (calculation in zinc) significantly increased the jejunum mass and ameliorated mucosa injury caused by 2 mg/kg BW DON treatment, including improvement of the intestinal morphology and barrier, as well as enteroid-forming and -budding efficiency, which was expanded from crypt cells isolated from jejunum of mice in each group. The repair process stimulated by Zn-Asp was also accompanied by increased fluorescence signal intensity of KRT20 and Villin; increased numbers of MUC2⁺, CAG⁺, LYZ⁺, BrdU⁺ and Ki67⁺ cells in mouse jejunum; and protein expression of Ki67 and PCNA in the jejunum, crypt and enteroid. Simultaneously, Zn-Asp increased ISC activity to promote intestinal epithelial renewal even under physiological conditions. These results were further verified in ex vivo enteroid culture experiments, which were treated with 100 μmol/L Zn-Asp (calculation in zinc) and 100 ng/mL DON for 72 h. Furthermore, we demonstrated that Zn-Asp improved intestinal integrity or accelerated wound healing along with Wnt/β-catenin signaling upregulation or reactivation. Our findings indicate Zn-Asp, especially Zn, enhances ISC activity to maintain the intestinal integrity by activating the Wnt/β-catenin signaling, which sheds some light upon effective preventive strategies for intestinal injury induced by mycotoxin based on ISCs with exogenous zinc preparations in the proper drugs, health foods or qualified feed.

Tumoral Expression of CD166 in Human Esophageal Squamous Cell Carcinoma: Implications for Cancer Progression and Prognosis

Accumulating data showed that cancer stem cells (CSCs) identified by cell surface markers contribute to the initiation, progression, and prognosis of human cancers. In this study, the expression of CSC candidates CD166, CD44, and Lgr5 in 65 cases of esophageal squamous cell carcinoma (ESCC) and 16 cases of control esophageal tissues were examined with immunohistochemistry (IHC). The correlation between tumoral expression levels of these CSC candidates and clinicopathological variables was analyzed. IHC results showed that the expression of CD166 in esophageal control tissues was completely negative, but it was in 87.69% (57/65) ESCC tissues. The expression of CD44 and Lgr5 did not differ between esophageal control tissues and ESCC tissues (p > 0.05). In addition, there were not correlations found among the expression levels of CD166, CD44, and Lgr5 in ESCC tissues. Clinicopathological analysis revealed that the tumoral expression level of CD166 correlated with lymph node involvement and TNM staging in patients with ESCC, and lower tumoral expression of CD44 was found in patients with advanced TNM staging. Kaplan-Meier survival curves suggested that expression level of CD166 appeared to have a negative impact on overall survival rate after surgery in patients with ESCC. Such impact was not found in other two CSC candidates. The authors therefore conclude that CD166 is a potential prognostic biomarker and correlates with advanced progression features in patients with ESCC.

In silico Analysis, Molecular Docking, Molecular Dynamic, Cloning, Expression and Purification of Chimeric Protein in Colorectal Cancer Treatment

Introduction

Colorectal cancer (CRC) is a type of cancer in humans that leads to high mortality and morbidity. CD166 and CD326 are immunoglobulins that are associated with cell migration. These molecules are included in tumorigenesis of CRC and serve a great marker of CRC stem cells. In the present study, we devised a novel chimeric protein including the V₁-domain of the CD166 and two epitopes of CD326 to use in diagnostic or therapeutic applications.

Methods

In silico techniques were launched to characterize the properties and structure of the protein. We have predicted physicochemical properties, structures, stability, MHC class I binding properties and ligand-receptor interaction of this chimeric protein by means of computational bioinformatics tools and servers. The sequence of chimeric gene was optimized for expression in prokaryotic host using online tools and cloned into pET-28a plasmid. The recombinant pET28a was transformed into the E. coli BL21DE3. Expression of recombinant protein was examined by SDS-PAGE and Western blotting.

Results

The designed chimeric protein retained high stability and the same immunogenicity as of the original proteins. Bioinformatics data indicated that the epitopes of the synthetic chimeric protein might induce B-cell- and T-cell-mediated immune responses. Furthermore, a gene was synthesized using the codon bias of a prokaryotic expression system. This synthetic gene expressed a bacterial expression system. The recombinant protein with molecular weights of 27kDa was expressed and confirmed by anti-his Western blot analysis.

Conclusion

The designed recombinant protein may be useful as a CRC diagnostic tool and for developing a protective vaccine against CRC.

Methionine and Its Hydroxyl Analogues Improve Stem Cell Activity To Eliminate Deoxynivalenol-Induced Intestinal Injury by Reactivating Wnt/β-Catenin Signaling

The intestinal epithelium is derived from intestinal stem cells (ISCs) and has direct contact with nutrients and toxins. However, whether methionine (Met) or a methionine hydroxyl analogue (2-hydroxy-4-(methylthio)butanoic acid (HMB)) can alleviate deoxynivalenol (DON)-induced intestinal injury remains unknown. Mice were treated orally with Met or HMB on days 1-11 and with DON on days 4-8. On day 12, the mice were sacrificed, and the jejunum was collected for crypt isolation and culture. Mouse enteroids were treated with DON and Met or HMB ex vivo. The results showed that Met and HMB increased the average daily feed intake and average daily gain of the mice. Met and HMB also improved the jejunal structure and barrier integrity and promoted ISC expansion, as indicated by the increased enteroid formation efficiency and area, under DON-induced injury conditions. In addition, DON-induced decreases in ISC activity were rescued Wnt/β-catenin signaling reactivation by Met or HMB in vivo and ex vivo. Collectively, our findings reveal that Met and HMB alleviated DON-induced intestinal injury by improving ISC expansion and reactivating Wnt/β-catenin signaling. Our study thus provides a nutritional intervention for intestinal diseases involving Wnt/β-catenin signaling.

Decreased ALCAM expression and promoter hypermethylation is associated with preeclampsia

Preeclampsia (PE) is a major obstetrical complication that results in maternal and fetal morbidity and mortality. Aberrant epigenetic modifications are widely involved in the pathogenesis of PE. Previously, the activated leukocyte cell adhesion molecule (ALCAM) was reported to be required for blastocyst implantation but has not been described in the context of pathological pregnancy. This study explored the expression of ALCAM and its methylation levels in the placentas and peripheral venous blood of patients with PE from a Chinese Han population. The mRNA and protein expression levels of ALCAM were downregulated in the PE placentas compared with the control placentas (P < 0.05). The methylation rate of the ALCAM gene promoter was considerably elevated in the placentas (P = 0.003, odds ratio (OR) = 0.264, 95% confidence interval (95% CI) [0.108-0.647], cases n = 47, controls n = 53) and peripheral blood (P = 0.007, OR = 0.455, 95% CI [0.256-0.806], cases n = 100, controls n = 100) of the PE patients compared with those of the normotensive women, suggesting a negative relationship between ALCAM methylation and gene transcription. Moreover, the transcriptional expression of ALCAM was dramatically increased by demethylating treatment in trophoblastic cells. ALCAM is expected to be involved in the pathogenesis of PE through methylation regulation.

Exosomes, metastases, and the miracle of cancer stem cell markers

Cancer-initiating cells (CIC) are the driving force in tumor progression. There is strong evidence that CIC fulfill this task via exosomes (TEX), which modulate and reprogram stroma, nontransformed cells, and non-CIC. Characterization of CIC, besides others, builds on expression of CIC markers, many of which are known as metastasis-associated molecules. We here discuss that the linkage between CIC/CIC-TEX and metastasis-associated molecules is not fortuitously, but relies on the contribution of these markers to TEX biogenesis including loading and TEX target interactions. In addition, CIC markers contribute to TEX binding- and uptake-promoted activation of signaling cascades, transcription initiation, and translational control. Our point of view will be outlined for pancreas and colon CIC highly expressing CD44v6, Tspan8, EPCAM, claudin7, and LGR5, which distinctly but coordinately contribute to tumor progression. Despite overwhelming progress in unraveling the metastatic cascade and the multiple tasks taken over by CIC-TEX, there remains a considerable gap in linking CIC biomarkers, TEX, and TEX-initiated target modulation with metastasis. We will try to outline possible bridges, which could allow depicting pathways for new and expectedly powerful therapeutic interference with tumor progression.

Constitutive STAT5 activation regulates Paneth and Paneth-like cells to control Clostridium difficile colitis

Clostridium difficile impairs Paneth cells, driving intestinal inflammation that exaggerates colitis. Besides secreting bactericidal products to restrain C. difficile, Paneth cells act as guardians that constitute a niche for intestinal epithelial stem cell (IESC) regeneration. However, how IESCs are sustained to specify Paneth-like cells as their niche remains unclear. Cytokine-JAK-STATs are required for IESC regeneration. We investigated how constitutive STAT5 activation (Ca-pYSTAT5) restricts IESC differentiation towards niche cells to restrain C. difficile infection. We generated inducible transgenic mice and organoids to determine the effects of Ca-pYSTAT5-induced IESC lineages on C. difficile colitis. We found that STAT5 absence reduced Paneth cells and predisposed mice to C. difficile ileocolitis. In contrast, Ca-pYSTAT5 enhanced Paneth cell lineage tracing and restricted Lgr5 IESC differentiation towards pYSTAT5+Lgr5-CD24+Lyso+ or cKit+ niche cells, which imprinted Lgr5hiKi67+ IESCs. Mechanistically, pYSTAT5 activated Wnt/β-catenin signaling to determine Paneth cell fate. In conclusion, Ca-pYSTAT5 gradients control niche differentiation. Lack of pYSTAT5 reduces the niche cells to sustain IESC regeneration and induces C. difficile ileocolitis. STAT5 may be a transcription factor that regulates Paneth cells to maintain niche regeneration.

Effects of mutations in porcine miRNA-215 precursor sequences on miRNA-215 regulatory function

MicroRNAs (miRNAs) play an important role in animal growth and disease development, and sequence variation in microRNAs can alter their functions. Herein, we explored the effects of mutations in the miRNA-215 precursor sequence on the miRNA-215 regulatory network and resistance to Escherichia coli (E. coli). Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was used to detect sequence variations in Sutai and Meishan pigs. The miR-192 precursor sequence was not mutated, but the miR-215 precursor included an AT insertion mutation at position 6 (start from the first base of the miR-215 precursor) and a C/T mutation at position 43. Wild-type (WT) and mutant miR-215 precursor expression vectors were constructed to investigate the effects of sequence variation on expression of miR-215 and its target genes DLG5 and ALCAM, cytokine levels and E. coli adhesion. Compared with the WT control group, cells harbouring the C/T mutant vector displayed reduced miR-215 expression, increased target gene expression, elevated cytokine levels and rising E. coli adhesion, whereas cells harbouring the AT insertion mutant vector were not significantly changed. The sequence variation in the miRNA-215 precursor may affect the miRNA-215 regulatory network, and alter the stability of intestinal epithelial cells (IPEC-J2 cells) and resistance to E. coli. Our findings provide guidance for future research on the regulatory mechanisms of miR-215 in porcine resistance to E. coli F18, and identifying effective genetic markers against this organism.

Modulation of cell adhesion and migration through regulation of the immunoglobulin superfamily member ALCAM/CD166

In epithelial-derived cancers, altered regulation of cell-cell adhesion facilitates the disruption of tissue cohesion that is central to the progression to malignant disease. Although numerous intercellular adhesion molecules participate in epithelial adhesion, the immunoglobulin superfamily (IgSF) member activated leukocyte cell adhesion molecule (ALCAM), has emerged from multiple independent studies as a central contributor to tumor progression. ALCAM is an archetypal member of the IgSF with conventional organization of five Ig-like domains involved in homo- and heterotypic adhesions. Like many IgSF members, ALCAM is broadly expressed and involved in cellular adhesion across many cellular processes. While the redundancy of intercellular adhesion molecules (CAMs) could diminish the impact of any single CAM, consistent correlation between ALCAM expression and patient outcome for multiple cancers underscores its role in tumor progression. Unlike most oncogenes and tumor suppressors, ALCAM is neither mutated nor amplified or deleted. Experimental disruption of ALCAM-mediated adhesions implies that this IgSF member contributes to tumor progression through dynamic turnover of the protein at the cell surface. Since ALCAM is not frequently altered at the gene level, it appears to promote malignant behavior through regulation of its availability rather than its specific activity. These observations help explain its heterogeneous expression within malignant disease and the drastic changes in protein levels across tumor progression. To reveal how ALCAM contributes to tumor progression, we review regulation of its gene expression, alternative splicing, targeted proteolysis, binding partners, and surface shedding within the context of cancer. Studying ALCAM regulation has led to a novel understanding of the fine-tuning of cell adhesive state through the utilization of otherwise normal regulatory processes, which thereby enable tumor cell invasion and metastasis.

Isolation and biological characteristics of multipotent mesenchymal stromal cells derived from chick embryo intestine

1. Over the past decade, rapid advancement in isolation methods for identifying markers of the once elusive intestinal stem cell (ISC) populations has laid the foundation for unravelling their complex interrelationships during homeostasis. Study on ISC in avian intestinal tissue might play a pivotal foundation for further studies on the epithelial-to-mesenchymal transition (EMT) in gastrointestinal disease and cell-based therapy as well as intestinal tissue engineering. 2. The following experiment isolated a population of fibroblast-like, plastic adhering cells derived from chick embryo intestine, showing a strong self-renewing and proliferative ability, which was maintained in vitro up to passage 25. The findings included growth characteristics, detected expression of cell surface markers and characterised the capability of these cells to differentiate towards the osteogenic, adipogenic, and chondrogenic cell lineages. 3. RT-PCR analysis showed that these cells from chick embryos expressed mesenchymal stromal cell markers CD44, CD90 and VIMENTIN as well as ISC-specific genes LGR5, MI1, SMOC2, BMI1, and HOPX. Immunofluorescence and flow cytometry confirmed this biology characterisation further. 4. In conclusion, cells were isolated from the intestine of 18-day-old chicken embryos that exhibited the biological characteristics of mesenchymal stromal cells as well as markers of intestinal stem cells. Our findings may provide a novel insight for in vitro cell culture and characteristics of ISCs in avian species, which may also indicate a benefit for obtaining cell source for intestinal tissue engineering as well as cell-based investigation for gastrointestinal disease and treatment.

Monoclonal Antibodies Reveal Dynamic Plasticity Between Lgr5- and Bmi1-Expressing Intestinal Cell Populations

BACKGROUND & AIMS

Continual renewal of the intestinal epithelium is dependent on active- and slow-cycling stem cells that are confined to the crypt base. Tight regulation of these stem cell populations maintains homeostasis by balancing proliferation and differentiation to support critical intestinal functions. The hierarchical relation of discrete stem cell populations in homeostasis or during regenerative epithelial repair remains controversial. Although recent studies have supported a model for the active-cycling leucine-rich repeat-containing G-protein-coupled receptor 5 (Lgr5)⁺ intestinal stem cell (ISC) functioning upstream of the slow-cycling B lymphoma Mo-MLV insertion region 1 homolog (Bmi1)-expressing cell, other studies have reported the opposite relation. Tools that facilitate simultaneous analyses of these populations are required to evaluate their coordinated function.

METHODS

We used novel monoclonal antibodies (mAbs) raised against murine intestinal epithelial cells in conjunction with ISC-green fluorescent protein (GFP) reporter mice to analyze relations between ISC populations by microscopy. Ex vivo 3-dimensional cultures, flow cytometry, and quantitative reverse-transcription polymerase chain reaction analyses were performed.

RESULTS

Two novel mAbs recognized distinct subpopulations of the intestinal epithelium and when used in combination permitted isolation of discrete Lgr5^GFP and Bmi1^GFP-enriched populations with stem activity. Growth from singly isolated Lgr5^GFP ISCs gave rise to small spheroids. Spheroids did not express Lgr5^GFP and instead up-regulated Bmi1^GFP expression. Conversely, Bmi1-derived spheroids initiated Lgr5^GFP expression as crypt domains were established.

CONCLUSIONS

These data showed the functional utility of murine mAbs in the isolation and investigation of Lgr5^GFP and Bmi1^GFP ISC-enriched populations. Ex vivo analyses showed hierarchical plasticity between different ISC-expressing states; specifically Lgr5^GFP ISCs gave rise to Bmi1^GFP cells, and vice versa. These data highlight the impact of temporal and physiological context on unappreciated interactions between Lgr5^GFP and Bmi1^GFP cells during crypt formation.

Roles of microRNAs and RNA-Binding Proteins in the Regulation of Colorectal Cancer Stem Cells

Colorectal cancer stem cells (CSCs) are responsible for the initiation, progression and metastasis of human colorectal cancers, and have been characterized by the expression of cell surface markers, such as CD44, CD133, CD166 and LGR5. MicroRNAs (miRNAs) are differentially expressed between CSCs and non-tumorigenic cancer cells, and play important roles in the maintenance and regulation of stem cell properties of CSCs. RNA binding proteins (RBPs) are emerging epigenetic regulators of various RNA processing events, such as splicing, localization, stabilization and translation, and can regulate various types of stem cells. In this review, we summarize current evidences on the roles of miRNA and RBPs in the regulation of colorectal CSCs. Understanding the epigenetic regulation of human colorectal CSCs will help to develop biomarkers for colorectal cancers and to identify targets for CSC-targeting therapies.

Porcine Esophageal Submucosal Gland Culture Model Shows Capacity for Proliferation and Differentiation

BACKGROUND & AIMS

Although cells comprising esophageal submucosal glands (ESMGs) represent a potential progenitor cell niche, new models are needed to understand their capacity to proliferate and differentiate. By histologic appearance, ESMGs have been associated with both overlying normal squamous epithelium and columnar epithelium. Our aim was to assess ESMG proliferation and differentiation in a 3-dimensional culture model.

METHODS

We evaluated proliferation in human ESMGs from normal and diseased tissue by proliferating cell nuclear antigen immunohistochemistry. Next, we compared 5-ethynyl-2'-deoxyuridine labeling in porcine ESMGs in vivo before and after esophageal injury with a novel in vitro porcine organoid ESMG model. Microarray analysis of ESMGs in culture was compared with squamous epithelium and fresh ESMGs.

RESULTS

Marked proliferation was observed in human ESMGs of diseased tissue. This activated ESMG state was recapitulated after esophageal injury in an in vivo porcine model, ESMGs assumed a ductal appearance with increased proliferation compared with control. Isolated and cultured porcine ESMGs produced buds with actively cycling cells and passaged to form epidermal growth factor-dependent spheroids. These spheroids were highly proliferative and were passaged multiple times. Two phenotypes of spheroids were identified: solid squamous (P63+) and hollow/ductal (cytokeratin 7+). Microarray analysis showed spheroids to be distinct from parent ESMGs and enriched for columnar transcripts.

CONCLUSIONS

Our results suggest that the activated ESMG state, seen in both human disease and our porcine model, may provide a source of cells to repopulate damaged epithelium in a normal manner (squamous) or abnormally (columnar epithelium). This culture model will allow the evaluation of factors that drive ESMGs in the regeneration of injured epithelium. The raw microarray data have been uploaded to the National Center for Biotechnology Information Gene Expression Omnibus (accession number: GSE100543).

Recent Advances in Intestinal Stem Cells

Purpose of review

The intestine is a dynamic organ with rapid stem cell division generating epithelial cells that mature and apoptose in 3-5 days. Rapid turnover maintains the epithelial barrier and homeostasis. Current insights on intestinal stem cells (ISCs) and their regulation are discussed here.

Recent findings

The Lgr5+ ISCs maintain intestinal homeostasis by dividing asymmetrically, but also divide symmetrically to extinguish or replace ISCs. Following radiation or mucosal injury, reserve BMI1+ ISCs as well as other crypt cells can de-differentiate into Lgr5+ ISCs. ISC niche cells, including Paneth, immune and myofibroblast cells secrete factors that regulate ISC proliferation. Finally, several studies indicate that the microbiome metabolites regulate ISC growth.

Summary

ISC cells can be plastic and integrate a complexity of environmental/niche cues to trigger or suppress proliferation as needed.