Goblet Cell Lineage Research Articles

Hydrogel-Integrated Millifluidic Systems: Advancing the Fabrication of Mucus-Producing Human Intestinal Models.

The luminal surface of the intestinal epithelium is protected by a vital mucus layer, which is essential for lubrication, hydration, and fostering symbiotic bacterial relationships. Replicating and studying this complex mucus structure in vitro presents considerable challenges. To address this, we developed a hydrogel-integrated millifluidic tissue chamber capable of applying precise apical shear stress to intestinal models cultured on flat or 3D structured hydrogel scaffolds with adjustable stiffness. The chamber is designed to accommodate nine hydrogel scaffolds, 3D-printed as flat disks with a storage modulus matching the physiological range of intestinal tissue stiffness (~3.7 kPa) from bioactive decellularized and methacrylated small intestinal submucosa (dSIS-MA). Computational fluid dynamics simulations were conducted to confirm a laminar flow profile for both flat and 3D villi-comprising scaffolds in the physiologically relevant regime. The system was initially validated with HT29-MTX seeded hydrogel scaffolds, demonstrating accelerated differentiation, increased mucus production, and enhanced 3D organization under shear stress. These characteristic intestinal tissue features are essential for advanced in vitro models as they critically contribute to a functional barrier. Subsequently, the chamber was challenged with human intestinal stem cells (ISCs) from the terminal ileum. Our findings indicate that biomimicking hydrogel scaffolds, in combination with physiological shear stress, promote multi-lineage differentiation, as evidenced by a gene and protein expression analysis of basic markers and the 3D structural organization of ISCs in the absence of chemical differentiation triggers. The quantitative analysis of the alkaline phosphatase (ALP) activity and secreted mucus demonstrates the functional differentiation of the cells into enterocyte and goblet cell lineages. The millifluidic system, which has been developed and optimized for performance and cost efficiency, enables the creation and modulation of advanced intestinal models under biomimicking conditions, including tunable matrix stiffness and varying fluid shear stresses. Moreover, the readily accessible and scalable mucus-producing cellular tissue models permit comprehensive mucus analysis and the investigation of pathogen interactions and penetration, thereby offering the potential to advance our understanding of intestinal mucus in health and disease.

Vitamin D opposes multilineage cell differentiation induced by Notch inhibition and BMP4 pathway activation in human colon organoids

Understanding the mechanisms involved in colonic epithelial differentiation is key to unraveling the alterations causing inflammatory conditions and cancer. Organoid cultures provide an unique tool to address these questions but studies are scarce. We report a differentiation system toward enterocytes and goblet cells, the two major colonic epithelial cell lineages, using colon organoids generated from healthy tissue of colorectal cancer patients. Culture of these organoids in medium lacking stemness agents resulted in a modest ultrastructural differentiation phenotype with low-level expression of enterocyte (KLF4, KRT20, CA1, FABP2) and goblet cell (TFF2, TFF3, AGR2) lineage markers. BMP pathway activation through depletion of Noggin and addition of BMP4 resulted in enterocyte-biased differentiation. Contrarily, blockade of the Notch pathway using the γ-secretase inhibitor dibenzazepine (DBZ) favored goblet cell differentiation. Combination treatment with BMP4 and DBZ caused a balanced strong induction of both lineages. In contrast, colon tumor organoids responded poorly to BMP4 showing only weak signals of cell differentiation, and were unresponsive to DBZ. We also investigated the effects of 1α,25-dihydroxyvitamin D3 (calcitriol) on differentiation. Calcitriol attenuated the effects of BMP4 and DBZ on colon normal organoids, with reduced expression of differentiation genes and phenotype. Consistently, in normal organoids, calcitriol inhibited early signaling by BMP4 as assessed by reduction of the level of phospho-SMAD1/5/8. Our results show that BMP and Notch signaling play key roles in human colon stem cell differentiation to the enterocytic and goblet cell lineages and that calcitriol modulates these processes favoring stemness features.

Aryl Hydrocarbon Receptor Activation Coordinates Mouse Small Intestinal Epithelial Cell Programming

In the face of mechanical, chemical, microbial, and immunologic pressure, intestinal homeostasis is maintained through balanced cellular turnover, proliferation, differentiation, and self-renewal. Here, we present evidence supporting the role of the aryl hydrocarbon receptor (AHR) in the adaptive reprogramming of small intestinal gene expression, leading to altered proliferation, lineage commitment, and remodeling of the cellular repertoire that comprises the intestinal epithelium to promote intestinal resilience. Ahr gene/protein expression and transcriptional activity exhibit marked proximalHI to distalLO and cryptHI to villiLO gradients. Genetic ablation of Ahr impairs commitment/differentiation of the secretory Paneth and goblet cell lineages and associated mucin production, restricts expression of secretory/enterocyte differentiation markers, and increases crypt-associated proliferation and villi-associated enterocyte luminal exfoliation. Ahr-/- mice display a decrease in intestinal barrier function. Ahr+/+ mice that maintain a diet devoid of AHR ligands intestinally phenocopy Ahr-/- mice. In contrast, Ahr+/+ mice exposed to AHR ligands reverse these phenotypes. Ligand-induced AHR transcriptional activity positively correlates with gene expression (Math1, Klf4, Tff3) associated with differentiation of the goblet cell secretory lineage. Math1 was identified as a direct target gene of AHR, a transcription factor critical to the development of goblet cells. These data suggest that dietary cues, relayed through the transcriptional activity of AHR, can reshape the cellular repertoire of the gastrointestinal tract.

Inference of cell state transitions and cell fate plasticity from single-cell with MARGARET.

Despite recent advances in inferring cellular dynamics using single-cell RNA-seq data, existing trajectory inference (TI) methods face difficulty in accurately reconstructing the cell-state manifold and cell-fate plasticity for complex topologies. Here, we present MARGARET (https://github.com/Zafar-Lab/Margaret) for inferring single-cell trajectory and fate mapping for diverse dynamic cellular processes. MARGARET reconstructs complex trajectory topologies using a deep unsupervised metric learning and a graph-partitioning approach based on a novel connectivity measure, automatically detects terminal cell states, and generalizes the quantification of fate plasticity for complex topologies. On a diverse benchmark consisting of synthetic and real datasets, MARGARET outperformed state-of-the-art methods in recovering global topology and cell pseudotime ordering. For human hematopoiesis, MARGARET accurately identified all major lineages and associated gene expression trends and helped identify transitional progenitors associated with key branching events. For embryoid body differentiation, MARGARET identified novel transitional populations that were validated by bulk sequencing and functionally characterized different precursor populations in the mesoderm lineage. For colon differentiation, MARGARET characterized the lineage for BEST4/OTOP2 cells and the heterogeneity in goblet cell lineage in the colon under normal and inflamed ulcerative colitis conditions. Finally, we demonstrated that MARGARET can scale to large scRNA-seq datasets consisting of ∼ millions of cells.

Autophagic State Confers Facultative Stem Cell Capacity in The Intestinal Epithelium

BackgroundThe intestinal epithelium is a highly proliferative tissue that undergoes complete turnover in 3 to 5 days. The presence of intestinal stem cells expressing the canonical Wnt target gene Lgr5, known as active intestinal stem cells (a‐ISCs), are responsible for generating daughter cells that differentiate into specialized epithelial cells to carryout various functions in the intestine. The proliferative nature of the intestinal epithelium renders it susceptible to DNA damage‐inducing injury, such as high‐dose irradiation and chemotherapy. Although a‐ISCs and early daughter cells are killed by these insults, a radio‐resistant population of facultative intestinal stem cells (f‐ISCs) can regenerate lost a‐ISCs to restore homeostasis following injury. The functional characteristics of f‐ISCs are becoming increasingly understood, however, whether any epithelial cell can act as an f‐ISC is less clear. One reason for this ambiguity is a heavy reliance on Cre‐driven reporter mouse models with low recombination efficiency. Our objective was to find a functional marker to identify f‐ISCs based on cellular state rather than gene expression. The autophagy pathway has been shown to protect against DNA damage and irradiation‐induced apoptosis in the intestinal epithelium. Furthermore, recent studies demonstrate a requirement for the autophagy pathway during cellular de‐differentiation in both gastric chief and pancreatic acinar cells following metaplasia‐inducing injury. Given that autophagy plays roles in both radio‐resistance and cellular plasticity, two integral features of f‐ISCs, we hypothesized that autophagic activity could serve to identify cells with f‐ISC capacity.Methods and ResultsUsing the autophagic vesicle tracer dye CytoID combined with fluorescence‐activated cell sorting, we demonstrate that intestinal epithelial cells with high levels of CytoID exhibit increased organoid‐formation efficiency (OFE) compared to CytoID ‘low’ cells. Single cell sequencing reveals that the CytoID high population is largely composed of secretory cells including Paneth, Goblet, Tuft, and Enteroendocrine cells, whereas the CytoID low population consisted mainly of a‐ISCs and absorptive Enterocytes. Using reporter mice and antibodies against cell surface receptors, we observe that CytoID can identify cells with high OFE within Enteroendocrine, Paneth, and Goblet cell lineages. Finally, we demonstrate that autophagy is required for the enhanced organoid‐formation observed in CytoID high cells by plating these cells in the presence of the lysosomal inhibitor Bafilomycin A1.ConclusionsOur new data support the notion that epithelial cells in a high autophagic state are biased to secretory lineages and that autophagy status functions as a lineage agnostic marker of f‐ISCs. Furthermore, our data suggests that autophagy is required for organoid formation in these lineages.

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.

Reduced Neurog3 Gene Dosage Shifts Enteroendocrine Progenitor Towards Goblet Cell Lineage in the Mouse Intestine.

Background & AimsTransient expression of Neurog3 commits intestinal secretory progenitors to become enteroendocrine-biased progenitors and hence drive enteroendocrine differentiation. Loss of Neurog3 in mouse resulted in the depletion of intestinal enteroendocrine cells (EECs) and an increase in goblet cells. Earlier studies in developing mouse pancreas identified a role of Neurog3 gene dosage in endocrine and exocrine cell fate allocation. We aimed to determine whether Neurog3 gene dosage controls fate choice of enteroendocrine progenitors.MethodsWe acquired mutant Neurog3 reporter mice carrying 2, 1, or null Neurog3 alleles to study Neurog3 gene dosage effect by lineage tracing. Cell types arising from Neurog3+ progenitors were determined by immunohistochemistry using antibodies against intestinal lineage-specific markers. RNA sequencing of sorted Neurog3+/+, Neurog3+/-, or bulk intestinal cells were performed and differentially expressed genes were analyzed.ResultsWe identified 2731 genes enriched in sorted Neurog3+/+-derived cells in the Neurog3+/+EYFP mouse intestine when compared with bulk duodenum epithelial cells. In the intestine of Neurog3+/-EGFP heterozygous mouse, we observed a 63% decrease in EEC numbers. Many Neurog3-derived cells stained for goblet marker Mucin 2. RNA sequencing of sorted Neurog3+/- cells uncovered enriched expression of genes characteristic for both goblet and enteroendocrine cells, indicating the mixed lineages arose from Neurog3+ progenitors. Consistent with this hypothesis, deletion of both Neurog3 alleles resulted in the total absence of EECs. All Neurog3+-derived cells stained for Mucin 2.ConclusionsWe identified that the fate of Neurog3+ enteroendocrine progenitors is dependent on Neurog3 gene dosage. High Neurog3 gene dosage enforces the commitment of secretory progenitors to an EE lineage, while constraining their goblet cell lineage potential. Transcriptome profiling data was deposited to Gene Ontology omnibus, accession number: GSE149203.

The integrity of the FOG-2 LXCXE pRb-binding motif is required for small intestine homeostasis.

What is the central question of this study? Do Fog2Rb-/Rb- mice present a defect of small intestine homeostasis? What is the main finding and its importance? The importance of interactions between FOG-2 and pRb in adipose tissue physiology has previously been demonstrated. Here it is shown that this interaction is also intrinsic to small intestine homeostasis and exerts extrinsic control over mouse metabolism. Thus, this association is involved in maintaining small intestine morphology, and regulating crypt proliferation and lineage differentiation. It therefore affects mouse growth and adaptation to a high-fat diet. GATA transcription factors and their FOG cofactors play a key role in tissue-specific development and differentiation, from worms to humans. We have shown that GATA-1 and FOG-2 contain an LXCXE pRb-binding motif. Interactions between retinoblastoma protein (pRb) and GATA-1 are crucial for erythroid proliferation and differentiation, whereas the LXCXE pRb-binding site of FOG-2 is involved in adipogenesis. Fog2-knock-in mice have defective pRb binding and are resistant to obesity, due to efficient white-into-brown fat conversion. Our aim was to investigate the pathophysiological impact of FOG-2-pRb interaction on the small intestine and mouse growth. Histological analysis of the small intestine revealed architectural changes in Fog2Rb-/Rb- mice, including villus shortening, with crypt expansion and a change in muscularis propria thickness. These differences were more marked in the proximo-distal part of the small intestine and were associated with an increase in crypt cell proliferation and disruption of the goblet and Paneth cell lineage. The small intestine of the mutants was unable to adapt to a high-fat diet, and had significantly lower plasma lipid levels on such a diet. Fog2Rb-/Rb- mice displayed higher levels of glucose-dependent insulinotropic peptide release, and lower levels of insulin-like growth factor I release on a regular diet. Their intestinal lipid absorption was impaired, resulting in restricted weight gain. In addition to the intrinsic effects of the mutation on adipose tissue, we show here an extrinsic relationship between the intestine and the effect of FOG-2 mutation on mouse metabolism. In conclusion, the interaction of FOG-2 with pRb coordinates the crypt-villus axis and controls small intestine homeostasis.

Proteomic Profiling of Enteroid Cultures Skewed toward Development of Specific Epithelial Lineages.

Recently, 3D small intestinal organoids (enteroids) have been developed from cultures of intestinal stem cells which differentiate in vitro to generate all the differentiated epithelial cell types associated with the intestine and mimic the structural properties of the intestine observed in vivo. Small-molecule drug treatment can skew organoid epithelial cell differentiation toward particular lineages, and these skewed enteroids may provide useful tools to study specific epithelial cell populations, such as goblet and Paneth cells. However, the extent to which differentiated epithelial cell populations in these skewed enteroids represent their in vivo counterparts is not fully understood. This study utilises label-free quantitative proteomics to determine whether skewing murine enteroid cultures toward the goblet or Paneth cell lineages results in changes in abundance of proteins associated with these cell lineages in vivo. Here, proteomics data confirms that skewed enteroids recapitulate important features of the in vivo gut environment, demonstrating that they can serve as useful models for the investigation of normal and disease processes in the intestine. Furthermore, comparison of mass spectrometry data with histology data contained within the Human Protein Atlas identifies putative novel markers for goblet and Paneth cells.

Sox4 Promotes Atoh1-Independent Intestinal Secretory Differentiation Toward Tuft and Enteroendocrine Fates

The intestinal epithelium is maintained by intestinal stem cells (ISCs), which produce postmitotic absorptive and secretory epithelial cells. Initial fate specification toward enteroendocrine, goblet, and Paneth cell lineages requires the transcription factor Atoh1, which regulates differentiation of the secretory cell lineage. However, less is known about the origin of tuft cells, which participate in type II immune responses to parasite infections and appear to differentiate independently of Atoh1. We investigated the role of Sox4 in ISC differentiation. We performed experiments in mice with intestinal epithelial-specific disruption of Sox4 (Sox4fl/fl:vilCre; SOX4 conditional knockout [cKO]) and mice without disruption of Sox4 (control mice). Crypt- and single-cell-derived organoids were used in assays to measure proliferation and ISC potency. Lineage allocation and gene expression changes were studied by immunofluorescence, real-time quantitative polymerase chain reaction, and RNA-seq analyses. Intestinal organoids were incubated with the type 2 cytokine interleukin 13 and gene expression was analyzed. Mice were infected with the helminth Nippostrongylus brasiliensis and intestinal tissues were collected 7 days later for analysis. Intestinal tissues collected from mice that express green fluorescent protein regulated by the Atoh1 promoter (Atoh1GFP mice) and single-cell RNA-seq analysis were used to identify cells that coexpress Sox4 and Atoh1. We generated SOX4-inducible intestinal organoids derived from Atoh1fl/fl:vilCreER (ATOH1 inducible knockout) mice and assessed differentiation. Sox4cKO mice had impaired ISC function and secretory differentiation, resulting in decreased numbers of tuft and enteroendocrine cells. In control mice, numbers of SOX4+ cells increased significantly after helminth infection, coincident with tuft cell hyperplasia. Sox4 was activated by interleukin 13 in control organoids; SOX4cKO mice had impaired tuft cell hyperplasia and parasite clearance after infection with helminths. In single-cell RNA-seq analysis, Sox4+/Atoh1- cells were enriched for ISC, progenitor, and tuft cell genes; 12.5% of Sox4-expressing cells coexpressed Atoh1 and were enriched for enteroendocrine genes. In organoids, overexpression of Sox4 was sufficient to induce differentiation of tuft and enteroendocrine cells-even in the absence of Atoh1. We found Sox4 promoted tuft and enteroendocrine cell lineage allocation independently of Atoh1. These results challenge the longstanding model in which Atoh1 is the sole regulator of secretory differentiation in the intestine and are relevant for understanding epithelial responses to parasitic infection.

Abstract 3675: Loss of alveolar type II epithelial and endothelial cell lineages in invasive mucinous adenocarcinoma of the lung (IMA)

Abstract Background: Invasive mucinous adenocarcinoma of the lung (IMA) is pathologically characterized as lung tumor cells with goblet cell morphology containing abundant intracytoplasmic mucin. IMA has been reported to account for 2-10% of lung adenocarcinomas. Genetically, the majority of IMA harbor KRAS mutations. Recently, by analyzing RNA-seq data using human IMA cases, we reported mucus-related genes specifically expressed in IMA, which includes MUC5AC, MUC5B, MUC3, SPDEF, FOXA3 and HNF4 (Guo, Tomoshige et al., 2017). Notably, immunohistochemical analyses have determined that NKX2-1 (also known as TTF-1) is reduced in IMA (Travis et al., 2011); however, other than NKX2-1, genes reduced in IMA compared to normal lungs have not been determined. Methods: In order to further understand the demographic occurrence of IMA, we surveyed the clinical records at the University of Cincinnati College of Medicine in the U.S. and Nagasaki University of School of Medicine in Japan. Genes reduced in IMA compared to normal lungs were identified using the RNA-seq datasets as we have previously reported (Guo, Tomoshige et al., 2017). Using single-cell and sorted RNA-seq datasets (LGEA; Du et al., 2017), genes were further categorized into groups that define different cell types that exist in normal lungs. Results: IMA occurred in 4.6% (3/65 cases in 2017) and 1.9% (2/105 cases in 2017) of lung adenocarcinomas at the University of Cincinnati College of Medicine and Nagasaki University of School of Medicine, respectively. Importantly, analysis using normal lung cell type specification markers obtained from the single-cell and sorted RNA-seq datasets identified that genes that define alveolar type II epithelial cells (e.g., SFTPC and ABCA3) and endothelial cells (e.g., FOXF1 and SOX17) were significantly reduced in IMA compared to normal lungs. Conclusion: IMA comprises mucus-producing goblet cell lineage populations devoid of alveolar type II epithelial and endothelial cell-lineage populations, suggesting a unique tumor microenvironment distinct from other lung adenocarcinomas. Citation Format: Koichi Tomoshige, Minzhe Guo, Tomoshi Tsuchiya, Iris Fink-Baldauf, Takeshi Nagayasu, Kelsey Dillehay McKillip, Yutaka Maeda. Loss of alveolar type II epithelial and endothelial cell lineages in invasive mucinous adenocarcinoma of the lung (IMA) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3675.

Determining the Mechanism by which PRDM16 Maintains the Adult Small Intestinal Epithelium

The intestinal epithelium is a well‐organized tissue that undergoes continuous cell turnover, with most cells being replaced every 4–5 days. PRDM16 is a large zinc‐finger containing transcription factor that, in addition to its well‐studied role in brown/beige adipose, regulates maintenance of neuronal and hematopoietic stem cells. However, the role of PRDM16 in other tissues is not well understood. We find that acute global deletion of Prdm16 in adult mice causes death within ten days. The Prdm16‐deleted mice begin to lose weight and appear weak and lethargic, with visibly distended and pale intestines. Histological analysis shows that PRDM16 is selectively and highly expressed in the intestinal epithelium of the duodenum and jejunum. Apoptotic cells are prevalent in the crypt, particularly in the transit amplifying zone by 3 days after Prdm16 deletion. By 5 days after deletion, intestinal tissue appears disorganized, with an abnormal accumulation of secretory cells in the crypt that express markers of both the goblet and Paneth cell lineages, indicating defects in differentiation. Interestingly, we could detect no obvious defects in Notch signaling. We performed RNA‐seq on isolated crypts to identify candidate signaling pathways that change in the intestine shortly after global knockout of Prdm16. A striking upregulation of P53‐activated apoptotic genes occurs immediately following the disappearance of PRDM16 protein, as well as an induction of Type‐I Interferon signaling. Independent of this, we see marked downregulation of genes involved in metabolic pathways. Studying the effects of PRDM16 ex vivo, we find that enteroid culture recapitulates the phenotypes observed in vivo, with Prdm16 deletion causing induction of apoptosis and a failure of intestinal enteroids to form buds. Further, we show that shRNA mediated knockdown of Prdm16 is sufficient to block the formation of enteroids. Our phenotype is ameliorated but not fully rescued by additional deletion of p53 both in vivo and ex vivo. We are currently focusing on defects in mitochondrial function, which appear to be a second major driver of our intestinal phenotype.Support or Funding InformationNRSA NIDDK F32 DK105743‐03 Pilot Grant NIDDK P30‐DK050306This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Lipopolysaccharide from Crypt-Specific Core Microbiota Modulates the Colonic Epithelial Proliferation-to-Differentiation Balance.

ABSTRACTWe identified a crypt-specific core microbiota (CSCM) dominated by strictly aerobic, nonfermentative bacteria in murine cecal and proximal colonic (PC) crypts and hypothesized that, among its possible functions, it may affect epithelial regeneration. In the present work, we isolated representative CSCM strains using selective media based upon our initial 16S rRNA-based molecular identification (i.e., Acinetobacter, Delftia, and Stenotrophomonas). Their tropism for the crypt was confirmed, and their influence on epithelial regeneration was demonstrated in vivo by monocolonization of germfree mice. We also showed that lipopolysaccharide (LPS), through its endotoxin activity, was the dominant bacterial agonist controlling proliferation. The relevant molecular mechanisms were analyzed using colonic crypt-derived organoids exposed to bacterial sonicates or highly purified LPS as agonists. We identified a Toll-like receptor 4 (TLR4)-dependent program affecting crypts at different stages of epithelial differentiation. LPS played a dual role: it repressed cell proliferation through RIPK3-mediated necroptosis of stem cells and cells of the transit-amplifying compartment and concurrently enhanced cell differentiation, particularly the goblet cell lineage.

Rack1 function in intestinal epithelia: regulating crypt cell proliferation and regeneration and promoting differentiation and apoptosis.

Previously, we showed that receptor for activated C kinase 1 (Rack1) regulates growth of colon cells in vitro, partly by suppressing Src kinase activity at key cell cycle checkpoints, in apoptotic and cell survival pathways and at cell-cell adhesions. Here, we generated mouse models of Rack1 deficiency to assess Rack1's function in intestinal epithelia in vivo. Intestinal Rack1 deficiency resulted in proliferation of crypt cells, diminished differentiation of crypt cells into enterocyte, goblet, and enteroendocrine cell lineages, and expansion of Paneth cell populations. Following radiation injury, the morphology of Rack1-deleted small bowel was strikingly abnormal with development of large polypoid structures that contained many partly formed villi, numerous back-to-back elongated and regenerating crypts, and high-grade dysplasia in surface epithelia. These abnormalities were not observed in Rack1-expressing areas of intestine or in control mice. Following irradiation, apoptosis of enterocytes was strikingly reduced in Rack1-deleted epithelia. These novel findings reveal key functions for Rack1 in regulating growth of intestinal epithelia: suppressing crypt cell proliferation and regeneration, promoting differentiation and apoptosis, and repressing development of neoplasia. NEW & NOTEWORTHY Our findings reveal novel functions for receptor for activated C kinase 1 (Rack1) in regulating growth of intestinal epithelia: suppressing crypt cell proliferation and regeneration, promoting differentiation and apoptosis, and repressing development of neoplasia.

Epithelial Src homology region 2 domain-containing phosphatase-1 restrains intestinal growth, secretory cell differentiation, and tumorigenesis.

Shp-1 (Src homology region 2 domain-containing protein tyrosine phosphatase-1) is a phosphatase that is highly expressed in hematopoietic and epithelial cells. Whereas its function is largely characterized in hematopoietic cells, its role in epithelial cells, such as intestinal epithelial cells (IECs), is not well known. Here, we generated mice with an IEC-specific knockout of Shp-1 (Src homology region 2 domain-containing phosphatase-1; Shp-1IEC-KO). We showed that the loss of epithelial Shp-1 leads to an intestinalomegaly that is associated with an increase in epithelial cell proliferation and size. Histologic analysis demonstrates significant perturbation of the crypt-villus architecture with an apparent increase in the number of goblet and Paneth cells and increased expression of their respective markers {Muc2 (mucin 2), αDef, and Sox9 [SRY (sex determining region Y)-box 9]}. Expansion of intermediate cells-common progenitors of goblet and Paneth cell lineages-is also observed in Shp-1IEC-KO mice. Although sustained activation of Wnt/β-catenin and PI3K/Akt/mammalian target of rapamycin signaling is observed, Shp-1IEC-KO mice fail to develop any intestinal tumors after 15 mo; however, the loss of Shp-1 in IECs markedly enhances tumor load ApcMin/+ mice. These findings show a novel role for Shp-1 in the regulation of IEC growth and secretory lineage allocation, possibly via modulation of PI3K/Akt-dependent signaling pathways. Finally, Shp-1 does not function as a classic tumor suppressor gene in the intestinal epithelium.-Leblanc, C., Langlois, M.-J., Coulombe, G., Vaillancourt-Lavigueur, V., Jones, C., Carrier, J. C., Boudreau, F., Rivard, N. Epithelial Src homology region 2 domain-containing phosphatase-1 restrains intestinal growth, secretory cell differentiation, and tumorigenesis.

Metformin Improves Ileal Epithelial Barrier Function in Interleukin-10 Deficient Mice.

Background and aimsThe impairment of intestinal epithelial barrier is the main etiologic factor of inflammatory bowel disease. The proper intestinal epithelial proliferation and differentiation is crucial for maintaining intestinal integrity. Metformin is a common anti-diabetic drug. The objective is to evaluate the protective effects of metformin on ileal epithelial barrier integrity using interleukin-10 deficient (IL10KO) mice.MethodsWild-type and IL10KO mice were fed with/without metformin for 6 weeks and then ileum was collected for analyses. The mediatory role of AMP-activated protein kinase (AMPK) was further examined by gain and loss of function study in vitro.ResultsCompared to wild-type mice, IL10KO mice had increased proliferation, reduced goblet cell and Paneth cell lineage differentiation in the ileum tissue, which was accompanied with increased crypt expansion. Metformin supplementation mitigated intestinal cell proliferation, restored villus/crypt ratio, increased goblet cell and Paneth cell differentiation and improved barrier function. In addition, metformin supplementation in IL10KO mice suppressed macrophage pro-inflammatory activity as indicated by reduced M1 macrophage abundance and decreased pro-inflammatory cytokine IL-1β, TNF-α and IFN-γ expressions. As a target of metformin, AMPK phosphorylation was enhanced in mice treated with metformin, regardless of mouse genotypes. In correlation, the mRNA level of differentiation regulator including bmp4, bmpr2 and math1 were also increased in IL10KO mice supplemented with metformin, which likely explains the enhanced epithelial differentiation in IL10KO mice with metformin. Consistently, in Caco-2 cells, metformin promoted claudin-3 and E-cadherin assembly and mitigated TNF-α-induced fragmentation of tight junction proteins. Gain and loss of function assay also demonstrated AMPK was correlated with epithelial differentiation and proliferation.ConclusionsMetformin supplementation promotes secretory cell lineage differentiation, suppresses inflammation and improves epithelial barrier function in IL10KO mice likely through activation of AMPK, showing its beneficial effects on gut epithelial.

Ketogenesis contributes to intestinal cell differentiation.

The intestinal epithelium undergoes a continual process of proliferation, differentiation and apoptosis. Previously, we have shown that the PI3K/Akt/mTOR pathway has a critical role in intestinal homeostasis. However, the downstream targets mediating the effects of mTOR in intestinal cells are not known. Here, we show that the ketone body β-hydroxybutyrate (βHB), an endogenous inhibitor of histone deacetylases (HDACs) induces intestinal cell differentiation as noted by the increased expression of differentiation markers (Mucin2 (MUC2), lysozyme, IAP, sucrase-isomaltase, KRT20, villin, Caudal-related homeobox transcription factor 2 (CDX2) and p21Waf1). Conversely, knockdown of the ketogenic mitochondrial enzyme hydroxymethylglutaryl CoA synthase 2 (HMGCS2) attenuated spontaneous differentiation in the human colon cancer cell line Caco-2. Overexpression of HMGCS2, which we found is localized specifically in the more differentiated portions of the intestinal mucosa, increased the expression of CDX2, thus further suggesting the contributory role of HMGCS2 in intestinal differentiation. In addition, mice fed a ketogenic diet demonstrated increased differentiation of intestinal cells as noted by an increase in the enterocyte, goblet and Paneth cell lineages. Moreover, we showed that either knockdown of mTOR or inhibition of mTORC1 with rapamycin increases the expression of HMGCS2 in intestinal cells in vitro and in vivo, suggesting a possible cross-talk between mTOR and HMGCS2/βHB signaling in intestinal cells. In contrast, treatment of intestinal cells with βHB or feeding mice with a ketogenic diet inhibits mTOR signaling in intestinal cells. Together, we provide evidence showing that HMGCS2/βHB contributes to intestinal cell differentiation. Our results suggest that mTOR acts cooperatively with HMGCS2/βHB to maintain intestinal homeostasis.

Rapid Expansion of Human Epithelial Stem Cells Suitable for Airway Tissue Engineering

Stem cell-based tracheal replacement represents an emerging therapeutic option for patients with otherwise untreatable airway diseases including long-segment congenital tracheal stenosis and upper airway tumors. Clinical experience demonstrates that restoration of mucociliary clearance in the lungs after transplantation of tissue-engineered grafts is critical, with preclinical studies showing that seeding scaffolds with autologous mucosa improves regeneration. High epithelial cell-seeding densities are required in regenerative medicine, and existing techniques are inadequate to achieve coverage of clinically suitable grafts. To define a scalable cell culture system to deliver airway epithelium to clinical grafts. Human respiratory epithelial cells derived from endobronchial biopsies were cultured using a combination of mitotically inactivated fibroblasts and Rho-associated protein kinase (ROCK) inhibition using Y-27632 (3T3+Y). Cells were analyzed by immunofluorescence, quantitative polymerase chain reaction, and flow cytometry to assess airway stem cell marker expression. Karyotyping and multiplex ligation-dependent probe amplification were performed to assess cell safety. Differentiation capacity was tested in three-dimensional tracheospheres, organotypic cultures, air-liquid interface cultures, and an in vivo tracheal xenograft model. Ciliary function was assessed in air-liquid interface cultures. 3T3-J2 feeder cells and ROCK inhibition allowed rapid expansion of airway basal cells. These cells were capable of multipotent differentiation in vitro, generating both ciliated and goblet cell lineages. Cilia were functional with normal beat frequency and pattern. Cultured cells repopulated tracheal scaffolds in a heterotopic transplantation xenograft model. Our method generates large numbers of functional airway basal epithelial cells with the efficiency demanded by clinical transplantation, suggesting its suitability for use in tracheal reconstruction.

SHP-2 Phosphatase Prevents Colonic Inflammation by Controlling Secretory Cell Differentiation and Maintaining Host-Microbiota Homeostasis.

Polymorphisms in the PTPN11 gene encoding for the tyrosine phosphatase SHP‐2 were described in patients with ulcerative colitis. We have recently demonstrated that mice with an intestinal epithelial cell‐specific deletion of SHP‐2 (SHP‐2IEC‐KO) develop severe colitis 1 month after birth. However, the mechanisms by which SHP‐2 deletion induces colonic inflammation remain to be elucidated. We generated SHP‐2IEC‐KO mice lacking Myd88 exclusively in the intestinal epithelium. The colonic phenotype was histologically analyzed and cell differentiation was determined by electron microscopy and lysozyme or Alcian blue staining. Microbiota composition was analyzed by 16S sequencing. Results show that innate defense genes including those specific to Paneth cells were strongly up‐regulated in SHP‐2‐deficient colons. Expansion of intermediate cells (common progenitors of the Goblet and Paneth cell lineages) was found in the colon of SHP‐2IEC‐KO mice whereas Goblet cell number was clearly diminished. These alterations in Goblet/intermediate cell ratio were noticed 2 weeks after birth, before the onset of inflammation and were associated with significant alterations in microbiota composition. Indeed, an increase in Enterobacteriaceae and a decrease in Firmicutes were observed in the colon of these mice, indicating that dysbiosis also occurred prior to inflammation. Importantly, loss of epithelial Myd88 expression inhibited colitis development in SHP‐2IEC‐KO mice, rescued Goblet/intermediate cell ratio, and prevented NFκB hyperactivation and inflammation. These data indicate that SHP‐2 is functionally important for the maintenance of appropriate barrier function and host‐microbiota homeostasis in the large intestine. J. Cell. Physiol. 231: 2529–2540, 2016. © 2016 The Authors. Journal of Cellular Physiology published by Wiley Periodicals, Inc.

Abstract B24: Differentiation screen identifies small molecules that target histologically divergent subtypes of patient-derived lung cancer stem cells

Abstract Non-small cell lung cancer (NSCLC) is a prevalent and deadly disease because of high incidence and relapse rates. One hypothesis for the high relapse rate is the existence of cancer stem cells (CSCs), a rare subpopulation of cells within these tumors, that are resistant to therapy and thought to be responsible for local and distal recurrence. CSCs are also able to self-renew and differentiate into multiple cell types forming the mass of new tumors. These differentiated progeny that constitute the bulk of the tumor are more sensitive to radiation and chemotherapeutic agents, express tissue of origin markers, and have an intrinsically limited lifespan. While most solid tumors have these properties, the degree of heterogeneity from patient to patient in the multi-lineage potential of the CSC population is not known. In particular, NSCLC CSC populations from primary patient tumors have not been well studied. The goal of this study was to characterize newly derived NSCLC CSC lines to determine the degree of heterogeneity between patient samples, and to provide a starting point for the discovery of novel differentiation therapeutic agents to target CSCs. We isolated six CSC lines from primary patient NSCLC tumors using an unbiased culture-based enrichment method, rather than a biased marker-based approach. Each of these six CSC lines was tumorigenic in immunodeficient mice at low cell numbers and the resulting tumors recapitulated the original tumor histology. All-trans retinoic acid (ATRA), a well-known differentiation agent for the treatment of acute promyelocytic leukemia (APL), maintains the normal growth and differentiation of human bronchial epithelial cells in culture. Each of the six CSC lines was treated with ATRA for two weeks to induce differentiation and then assessed for transcript and protein levels of candidate CSC and differentiation markers. Pre-treatment, the CSC lines all expressed CD44. Post-ATRA treatment, the majority of the CSC lines expressed Mucin-2, a marker of Goblet cell lineage. In addition, each cell line started to show evidence of the very early stages of differentiation into other lineages including Clara Cells, Neuroendocrine Cells, and Alveolar Type I and Type II cells. In one CSC line, ATRA treatment both in vitro and in vivo delayed tumor cell growth, induced the expression of Mucin-2 and decreased the expression of Nestin, a cancer stem cell marker. To further characterize CSC differentiation potential, we screened a pilot set of small molecules in two independent CSC lines to identify compounds that induce terminal differentiation, using Mucin-2 expression as readout. Surprisingly, despite the fact that these two CSC lines were from different histological subtypes (adenocarcinoma and squamous cell carcinoma) and displayed different transcriptional profiles post-differentiation, there was a good correlation between hit sets in the screens. Taken together, these data suggest that while the CSC of origin in tumors differs between patient samples in profile and function, there is promise to identify differentiation agents that are broadly active in different NSCLC subtypes. Further screening is currently being performed to identify these novel differentiation agents for therapeutic use. Citation Format: Dina Shlyakhter, Diane Boucher, Yong Gu, Amy B. Hall, Elaine Krueger, Anna Lindquist, Cheryl Murphy, Yuxin Wang, Mark Wood, Brenda Eustace. Differentiation screen identifies small molecules that target histologically divergent subtypes of patient-derived lung cancer stem cells. [abstract]. In: Proceedings of the AACR Special Conference: Developmental Biology and Cancer; Nov 30-Dec 3, 2015; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(4_Suppl):Abstract nr B24.