Porcine Deltacoronavirus Infection Disrupts the Intestinal Mucosal Barrier and Inhibits Intestinal Stem Cell Differentiation to Goblet Cells via the Notch Signaling Pathway

Goblet cells and their secreted mucus are important elements of the intestinal mucosal barrier, which allows host cells to resist invasion by intestinal pathogens. Porcine deltacoronavirus (PDCoV) is an emerging swine enteric virus that causes severe diarrhea in pigs and causes large economic losses to pork producers worldwide. To date, the molecular mechanisms by which PDCoV regulates the function and differentiation of goblet cells and disrupts the intestinal mucosal barrier remain to be determined. Here, we report that in newborn piglets, PDCoV infection disrupts the intestinal barrier: specifically, there is intestinal villus atrophy, crypt depth increases, and tight junctions are disrupted. There is also a significant reduction in the number of goblet cells and the expression of MUC-2. In vitro, using intestinal monolayer organoids, we found that PDCoV infection activates the Notch signaling pathway, resulting in upregulated expression of HES-1 and downregulated expression of ATOH-1 and thereby inhibiting the differentiation of intestinal stem cells into goblet cells. Our study shows that PDCoV infection activates the Notch signaling pathway to inhibit the differentiation of goblet cells and their mucus secretion, resulting in disruption of the intestinal mucosal barrier. IMPORTANCE The intestinal mucosal barrier, mainly secreted by the intestinal goblet cells, is a crucial first line of defense against pathogenic microorganisms. PDCoV regulates the function and differentiation of goblet cells, thereby disrupting the mucosal barrier; however, the mechanism by which PDCoV disrupts the barrier is not known. Here, we report that in vivo, PDCoV infection decreases villus length, increases crypt depth, and disrupts tight junctions. Moreover, PDCoV activates the Notch signaling pathway, inhibiting goblet cell differentiation and mucus secretion in vivo and in vitro. Thus, our results provide a novel insight into the mechanism underlying intestinal mucosal barrier dysfunction caused by coronavirus infection.

DOCK4 stimulates MUC2 production through its effect on goblet cell differentiation

The intestinal mucosa is in continuous contact with milliard of microorganisms, thus intestinal epithelial barrier is a critical component in the arsenal of defense mechanisms required to prevent infection and inflammation. Mucin 2 (MUC2), which is produced by the goblet cells, forms the skeleton of the intestinal mucus and protects the intestinal tract from self-digestion and numerous microorganisms. Dedicator of cytokinesis 4 (DOCK4) is a member of the DOCK-B subfamily of the DOCK family of guanine nucleotide exchange factors. It is reported that DOCK4 plays a critical role in the repair of the barrier function of the intestinal epithelium after chemical damage. In this study, the role of DOCK4 in the goblet cell differentiation and MUC2 production is explored. Disordered intestinal epithelium and shortage of goblet cells were observed in DOCK4 gene knockout mice. Furthermore, DOCK4 deletion contributed to the low expression of MUC2 and the goblet cell differentiation/maturation factors including growth factor independent 1 (Gfi1) and SAM pointed domain epithelial-specific transcription factor (Spdef) in mouse ileums and colons. Overexpression of DOCK4 caused a marked increase in Gfi1, Spdef, and MUC2, while siRNA knockdown of endogenous DOCK4 significantly decreased Gfi1, Spdef, and MUC2 in HT-29 cells. In addition, MUC2, DOCK4, and the goblet cell differentiation/maturation factors mRNA levels were decreased in colorectal cancer samples compared with normal colons. A significant positive correlation was found between MUC2 and DOCK4. In conclusion, DOCK4 may serve as a critical regulator of goblet cell differentiation and MUC2 production in the intestine.

Yap/Taz inhibit goblet cell fate to maintain lung epithelial homeostasis

Proper lung function relies on the precise balance of specialized epithelial cells that coordinate to maintain homeostasis. Herein, we describe essential roles for the transcriptional regulators YAP/TAZ in maintaining lung epithelial homeostasis, reporting that conditional deletion of Yap and Wwtr1/Taz in the lung epithelium of adult mice results in severe defects, including alveolar disorganization and the development of airway mucin hypersecretion. Through in vivo lineage tracing and in vitro molecular experiments, we reveal that reduced YAP/TAZ activity promotes intrinsic goblet transdifferentiation of secretory airway epithelial cells. Global gene expression and chromatin immunoprecipitation sequencing (ChIP-seq) analyses suggest that YAP/TAZ act cooperatively with TEA domain (TEAD) transcription factors and the NuRD complex to suppress the goblet cell fate program, directly repressing the SPDEF gene. Collectively, our study identifies YAP/TAZ as critical factors in lung epithelial homeostasis and offers molecular insight into the mechanisms promoting goblet cell differentiation, which is a hallmark of many lung diseases.

Acceleration of Small Intestine Development and Remodeling of the Microbiome Following Hyaluronan 35 kDa Treatment in Neonatal Mice

The beneficial effects of human milk suppressing the development of intestinal pathologies such as necrotizing enterocolitis in preterm infants are widely known. Human milk (HM) is rich in a multitude of bioactive factors that play major roles in promoting postnatal maturation, differentiation, and the development of the microbiome. Previous studies showed that HM is rich in hyaluronan (HA) especially in colostrum and early milk. This study aims to determine the role of HA 35 KDa, a HM HA mimic, on intestinal proliferation, differentiation, and the development of the intestinal microbiome. We show that oral HA 35 KDa supplementation for 7 days in mouse pups leads to increased villus length and crypt depth, and increased goblet and Paneth cells, compared to controls. We also show that HA 35 KDa leads to an increased predominance of Clostridiales Ruminococcaceae, Lactobacillales Lactobacillaceae, and Clostridiales Lachnospiraceae. In seeking the mechanisms involved in the changes, bulk RNA seq was performed on samples from the terminal ileum and identified upregulation in several genes essential for cellular growth, proliferation, and survival. Taken together, this study shows that HA 35 KDa supplemented to mouse pups promotes intestinal epithelial cell proliferation, as well as the development of Paneth cells and goblet cell subsets. HA 35 KDa also impacted the intestinal microbiota; the implications of these responses need to be determined.

Thyroid Hormones Regulate Goblet Cell Differentiation and Fgf19-Fgfr4 Signaling

Hypothyroidism is a common pathological condition characterized by insufficient activity of the thyroid hormones (THs), thyroxine (T4), and 3,5,3'-triiodothyronine (T3), in the whole body or in specific tissues. Hypothyroidism is associated with inadequate development of the intestine as well as gastrointestinal diseases. We used a zebrafish model of hypothyroidism to identify and characterize TH-modulated genes and cellular pathways controlling intestine development. In the intestine of hypothyroid juveniles and adults, the number of mucus-secreting goblet cells was reduced, and this phenotype could be rescued by T3 treatment. Transcriptome profiling revealed dozens of differentially expressed genes in the intestine of hypothyroid adults compared to controls. Notably, the expression of genes encoding to Fgf19 and its receptor Fgfr4 was markedly increased in the intestine of hypothyroid adults, and treatment with T3 normalized it. Blocking fibroblast growth factor (FGF) signaling, using an inducible dominant-negative Fgfr transgenic line, rescued the number of goblet cells in hypothyroid adults. These results show that THs inhibit the Fgf19-Fgfr4 signaling pathway, which is associated with inhibition of goblet cell differentiation in hypothyroidism. Both the TH and Fgf19-Fgfr4 signaling pathways can be pharmaceutical targets for the treatment of TH-related gastrointestinal diseases.

The Znt7-null mutation has sex dependent effects on the gut microbiota and goblet cell population in the mouse colon

Cellular homeostasis of zinc, an essential element for living organisms, is tightly regulated by a family of zinc transporters. The zinc transporter 7, ZnT7, is highly expressed on the membrane of the Golgi complex of intestinal epithelial cells and goblet cells. It has previously been shown that Znt7 knockout leads to zinc deficiency and decreased weight gain in C57BL/6 mice on a defined diet. However, effects within the colon are unknown. Given the expression profile of Znt7, we set out to analyze the changes in mucin density and gut microbial composition in the mouse large intestine induced by Znt7 knockout. We fed a semi-purified diet containing 30 mg Zn/kg to Znt7^-/- mice with their heterozygous and wild type littermates and found a sex specific effect on colonic mucin density, goblet cell number, and microbiome composition. In male mice Znt7 knockout led to increased goblet cell number and mucin density but had little effect on gut microbiome composition. However, in female mice Znt7 knockout was associated with decreased goblet cell number and mucin density, with increased proportions of the microbial taxa, Allobaculum, relative to wild type. The gut microbial composition was correlated with mucin density in both sexes. These findings suggest that a sex-specific relationship exists between zinc homeostasis, mucin production and the microbial community composition within the colon.

Ocular surface inflammation induces de novo expression of substance P in the trigeminal primary afferents with large cell bodies

We evaluated the changes in substance P (SP)-expressing trigeminal neurons (TNs) innervating the cornea following ocular surface inflammation. Ocular surface inflammation was induced in Sprague-Dawley rats using 0.1% benzalkonium chloride (BAK). The corneal staining score, corneal epithelial apoptosis, conjunctival goblet cells, and density of corneal subbasal nerve plexus (SNP) were assessed, and the mRNA levels of SP, interleukin (IL)-1β, IL-6, and tumour necrosis factor-α were measured in corneas and ipsilateral trigeminal ganglia (TG). SP-immunoreactivity (IR) was measured in corneal intraepithelial nerves and TNs. The cell size of corneal TNs in the TG was calculated. All parameters were observed immediately (BAK group), at 1 week (1 w group), and 2 months (2 m group) after 2 weeks of BAK application. BAK caused an increase in the corneal staining score and the number of apoptotic cells, loss of conjunctival goblet cells, reduced density of corneal SNP, and upregulated expression of SP and inflammatory cytokines in both the cornea and TG in the BAK group but those changes were not observed in the 2 m group. On the other hand, SP-IR% and mean cell size of corneal TNs increased significantly in the BAK, 1 w, and 2 m groups, compared to the control. Our data suggest that following ocular surface inflammation, large-sized corneal TNs which normally do not express SP, expressed it and this phenotype switching lasted even after the inflammation disappeared. Long-lasting phenotypic switch, as well as changes in the expression level of certain molecules should be addressed in future studies on the mechanism of corneal neuropathic pain.

Indoles from the commensal microbiota act via the AHR and IL-10 to tune the cellular composition of the colonic epithelium during aging

The intestinal epithelium is a highly dynamic structure that rejuvenates in response to acute stressors and can undergo alterations in cellular composition as animals age. The microbiota, acting via secreted factors related to indole, appear to regulate the sensitivity of the epithelium to stressors and promote epithelial repair via IL-22 and type I IFN signaling. As animals age, the cellular composition of the intestinal epithelium changes, resulting in a decreased proportion of goblet cells in the colon. We show that colonization of young or geriatric mice with bacteria that secrete indoles and various derivatives or administration of the indole derivative indole-3 aldehyde increases proliferation of epithelial cells and promotes goblet cell differentiation, reversing an effect of aging. To induce goblet cell differentiation, indole acts via the xenobiotic aryl hydrocarbon receptor to increase expression of the cytokine IL-10. However, the effects of indoles on goblet cells do not depend on type I IFN or on IL-22 signaling, pathways responsible for protection against acute stressors. Thus, indoles derived from the commensal microbiota regulate intestinal homeostasis, especially during aging, via mechanisms distinct from those used during responses to acute stressors. Indoles may have utility as an intervention to limit the decline of barrier integrity and the resulting systemic inflammation that occurs with aging.

Intestinal enteroids recapitulate the effects of short-chain fatty acids on the intestinal epithelium

Enteroids are cultured primary intestinal epithelial cells that recapitulate epithelial lineage development allowing for a more complex and physiologically relevant model for scientific study. The large presence of intestinal stem cells (ISC) in these enteroids allows for the study of metabolite effects on cellular processes and resulting progeny cells. Short-chain fatty acids (SCFA) such as butyrate (BUT) are bacterial metabolites produced in the gastrointestinal tract that are considered to be beneficial to host cells. Therefore, the objective was to study the effects of SCFAs on biomarkers of ISC activity, differentiation, barrier function and epithelial defense in the intestine using mouse and human enteroid models. Enteroids were treated with two concentrations of acetate (ACET), propionate (PROP), or BUT for 24 h. Enteroids treated with BUT or PROP showed a decrease in proliferation via EdU uptake relative to the controls in both mouse and human models. Gene expression of Lgr5 was shown to decrease with BUT and PROP treatments, but increased with ACET. As a result of BUT and PROP treatments, there was an increase in differentiation markers for enterocyte, Paneth, goblet, and enteroendocrine cells. Gene expression of antimicrobial proteins Reg3β, Reg3γ, and Defb1 were stimulated by BUT and PROP, but not by ACET which had a greater effect on expression of tight junction genes Cldn3 and Ocln in 3D enteroids. Similar results were obtained with human enteroids treated with 10 mM SCFAs and grown in either 3D or Transwell™ model cultures, although tight junctions were influenced by BUT and PROP, but not ACET in monolayer format. Furthermore, BUT and PROP treatments increased transepithelial electrical resistance after 24 h compared to ACET or control. Overall, individual SCFAs are potent stimulators of cellular gene expression, however, PROP and especially BUT show great efficacy for driving cell differentiation and gene expression.

Generation of Differentiating and Long-Living Intestinal Organoids Reflecting the Cellular Diversity of Canine Intestine

Functional intestinal disorders constitute major, potentially lethal health problems in humans. Consequently, research focuses on elucidating the underlying pathobiological mechanisms and establishing therapeutic strategies. In this context, intestinal organoids have emerged as a potent in vitro model as they faithfully recapitulate the structure and function of the intestinal segment they represent. Interestingly, human-like intestinal diseases also affect dogs, making canine intestinal organoids a promising tool for canine and comparative research. Therefore, we generated organoids from canine duodenum, jejunum and colon, and focused on simultaneous long-term expansion and cell differentiation to maximize applicability. Following their establishment, canine intestinal organoids were grown under various culture conditions and then analyzed with respect to cell viability/apoptosis and multi-lineage differentiation by transcription profiling, proliferation assay, cell staining, and transmission electron microscopy. Standard expansion medium supported long-term expansion of organoids irrespective of their origin, but inhibited cell differentiation. Conversely, transfer of organoids to differentiation medium promoted goblet cell and enteroendocrine cell development, but simultaneously induced apoptosis. Unimpeded stem cell renewal and concurrent differentiation was achieved by culturing organoids in the presence of tyrosine kinase ligands. Our findings unambiguously highlight the characteristic cellular diversity of canine duodenum, jejunum and colon as fundamental prerequisite for accurate in vitro modelling.

Comparative primary paediatric nasal epithelial cell culture differentiation and RSV-induced cytopathogenesis following culture in two commercial media

The culture of differentiated human airway epithelial cells allows the study of pathogen-host interactions and innate immune responses in a physiologically relevant in vitro model. As the use of primary cell culture has gained popularity the availability of the reagents needed to generate these cultures has increased. In this study we assessed two different media, Promocell and PneumaCult, during the differentiation and maintenance of well-differentiated primary nasal epithelial cell cultures (WD-PNECs). We compared and contrasted the consequences of these media on WD-PNEC morphological and physiological characteristics and their responses to respiratory syncytial virus (RSV) infection. We found that cultures generated using PneumaCult resulted in greater total numbers of smaller, tightly packed, pseudostratified cells. However, cultures from both media resulted in similar proportions of ciliated and goblet cells. There were no differences in RSV growth kinetics, although more ciliated cells were infected in the PneumaCult cultures. There was also significantly more IL-29/IFNλ1 secreted from PneumaCult compared to Promocell cultures following infection. In conclusion, the type of medium used for the differentiation of primary human airway epithelial cells may impact experimental results.

Cell-type-specific signaling networks in heterocellular organoids

Despite the widespread adoption of organoids as biomimetic tissue models, methods to comprehensively analyze cell-type-specific post-translational modification (PTM) signaling networks in organoids are absent. Here, we report multivariate single-cell analysis of such networks in organoids and organoid cocultures. Simultaneous analysis by mass cytometry of 28 PTMs in >1 million single cells derived from small intestinal organoids reveals cell-type- and cell-state-specific signaling networks in stem, Paneth, enteroendocrine, tuft and goblet cells, as well as enterocytes. Integrating single-cell PTM analysis with thiol-reactive organoid barcoding in situ (TOBis) enables high-throughput comparison of signaling networks between organoid cultures. Cell-type-specific PTM analysis of colorectal cancer organoid cocultures reveals that shApc, KrasG12D and Trp53R172H cell-autonomously mimic signaling states normally induced by stromal fibroblasts and macrophages. These results demonstrate how standard mass cytometry workflows can be modified to perform high-throughput multivariate cell-type-specific signaling analysis of healthy and cancerous organoids.

Consumption of an Oil Palm Fruit Extract Promotes Large Bowel Health in Rats

Oil palm fruit is widely used for edible oils, but the health benefits of other components are relatively unknown. We examined if consuming a polyphenol-rich extract of the fruit, from a vegetation by-product of oil processing, which also contains fibre, has gastro-intestinal benefits in rats on a Western-type diet (WD). The oil palm preparation (OPP) was added to food (OPP-F) or drinking water (OPP-D) to provide 50 mg of gallic acid equivalents (GAE)/d and compared to effects of high amylose maize starch (HAMS; 30%) in the diet or green tea extract (GT; 50 mg GAE/d) in drinking water over 4 wk. OPP treatments induced some significant effects (P < 0.05) compared to WD. OPP-D increased caecal digesta mass, caecal digesta concentrations of total SCFA, acetate and propionate (OPP-F increased caecal butyrate concentration), the numbers of mucus-producing goblet cells per colonic crypt, and caecal digesta abundance of some bacteria which may provide benefit to the host (Faecalibacterium prausnitzii, Akkermansia muciniphila and Ruminococcus gnavus). HAMS induced similar effects but with greater potency and had a broader impact on microbe populations, whereas GT had minimal impacts. These results suggest dietary OPP may benefit the large bowel.

Glutathione S-transferase theta 1 protects against colitis through goblet cell differentiation via interleukin-22

The enzyme glutathione S-transferase theta 1 (GSTT1) is involved in detoxifying chemicals, including reactive oxygen species (ROS). Here, we provide a significant insight into the role of GSTT1 in inflammatory bowel disease (IBD). We identified decreased expression of GSTT1 in inflamed colons from IBD patients compared to controls. We intrarectally or intraperitoneally delivered Gstt1 gene to mice with dextran sodium sulfate (DSS)-induced colitis and noted attenuation of colitis through gene transfer of Gstt1 via an IL-22 dependent pathway. Downregulation of GSTT1 by pathogen-associated molecular patterns (PAMPs) of microbes reduced innate defense responses and goblet cell differentiation. The GSTT1 mutation in intestinal epithelial cells (IECs) and IBD patients decreased its dimerization, which was connected to insufficient phosphorylation of signal transducer and activator of transcription-3 and p38/mitogen-activated protein kinase by their common activator, IL-22. GSTT1 ameliorated colitis and contributed as a modulator of goblet cells through sensing pathogens and host immune responses. Its mutations are linked to chronic intestinal inflammation due to its insufficient dimerization. Our results provide new insights into GSTT1 mutations that are linked to chronic intestinal inflammation due to its insufficient dimerization and their functional consequences in IBDs.

Lactobacillus reuteri Stimulates Intestinal Epithelial Proliferation and Induces Differentiation into Goblet Cells in Young Chickens

Probiotics, such as Lactobacillus, have been proven to be effective in maintaining intestinal homeostasis. The modulatory effect of Lactobacillus on intestinal epithelial development in early life is still unclear. In this study, Lactobacillus isolates with good probiotic abilities were screened and orally administered to detect their regulatory effect on intestinal development in chickens. L. reuteri 22 was isolated from chickens and chosen for subsequent chicken experiments due to its strong acid and bile salt resistance and ability to adhere to epithelial cells. The 3-day-old chickens were orally administrated with 10⁸ CFU L. reuteri 22 for consecutive 7 days. L. reuteri 22 increased Lgr5 mRNA expression (3.23 ± 0.40, P = 0.001) and activated the Wnt/β-catenin signaling pathway, with increasing expression of proliferating cell nuclear antigen (PCNA) (49.27 ± 9.81, P = 0.021) to support the proliferation of chicken intestinal epithelial cells. Moreover, L. reuteri 22 also inhibited the Notch signaling pathway to induce intestinal stem cell differentiation into goblet cells with increased mucin 2 (Muc-2) expression (1.72 ± 0.34, P = 0.047). L. reuteri 22 significantly enhanced lysozyme mRNA expression (2.32 ± 0.55, P = 0.019) to improve intestinal innate mucosal immunity. This study demonstrated that L. reuteri administration could regulate chicken intestinal epithelium development to ensure the function of the intestinal mucosal barrier, which is beneficial for newborn animals.

The Effect of Long-Term Use of an Eyewash Solution on the Ocular Surface Mucin Layer

The use of eyewash solutions in Japan, especially in patients with allergic conjunctivitis and contact lens wearers, has been increasing. Our aim was to investigate how the use of preservative-free eyewash solution in healthy eyes for one month affects corneal safety and ocular surface mucin. We analyzed 42 eyes of 21 individuals (17 males, four females; mean age: 36.1 ± 7.4 years) without ocular allergies, dry eyes, or other ocular diseases through a prospective study. Eyes were randomized to a wash group (group one) and a nonwash follow up group (group two). We evaluated the dry eye-related quality-of-life score (DEQS), tear film breakup time (TBUT), fluorescein staining score, mRNA expression of MUC5AC and MUC16, MUC16 immunohistochemistry, and MUC5AC periodic acid Schiff (PAS) staining. There was a significant decrease in DEQS scores after one month of eyewash use (p < 0.05). There were no significant differences in other evaluation items that were analyzed (all p > 0.05). Furthermore, no significant differences were observed between group one and group two in all endpoints (all p > 0.05). The results suggest that one month use of a nonpreserved eyewash solution has no detrimental effects on the tear film and the ocular surface mucins.

Proteolytic and Opportunistic Breaching of the Basement Membrane Zone by Immune Cells during Tumor Initiation

Cancer-related inflammation impacts significantly on cancer development and progression. From early stages, neutrophils and macrophages are drawn to pre-neoplastic cells in the epidermis, but before directly interacting, they must first breach the underlying extracellular matrix barrier layer that includes the basement membrane. Using several different skin cancer models and a collagen I-GFP transgenic zebrafish line, we have undertaken correlative light and electron microscopy (CLEM) to capture the moments when immune cells traverse the basement membrane. We show evidence both for active proteolytic burrowing and for the opportunistic use of pre-existing weak spots in the matrix layer. We show that these small holes, as well as much larger, cancer cell-generated or wound-triggered gaps in the matrix barrier, provide portals for immune cells to access cancer cells in the epidermis and thus are rate limiting in cancer progression.

Structural adequacy of the digestive tract supports dual feeding habit in catfish Pachypterus khavalchor (Siluriformes: Horabagridae)

Lepidophagy is comparatively rare amongst teleost fishes, yet our understanding of this specialization is lacking. Therefore we examined the digestive tract features of Pachypterus khavalchor using morphological, osteological, histological and histochemical techniques to comprehend and relate structural organization of digestive tract with scale eating habit. Morphologically, the alimentary canal is defined by a short and muscular esophagus, well-developed stomach and comparatively short intestine. Gut content analysis and intestinal coefficient value (0.53 ± 0.01) revealed that P. khavalchor exhibit both carnivory and lepidophagy. However, P. khavalchor primarily feeds on the scales (67.47%) and other chitin-rich material like aquatic insects (17.62%), aquatic larvae (8.66%) which affirms its solid association with chitinase producing endosymbionts in the gut. Lepidophagy is further supported by the osteological observations. The perfect segregation of the functions such as food capture, ingestion and processing amongst the different types of teeth located in the oral cavity and pharyngeal region thus could be taken as evolutionary adaptations in scale eaters to support lepidophagy. Specialized arrangement of the esophageal and stomach epithelial folds could be altogether taken as an adaptation with the end goal to frame the scale stacks and accordingly facilitate the handling and processing of chitin-rich bolus. The esophageal mucosa is simple squamous epithelium instead of stratified epithelium with numerous goblet cells to withstand the mechanical harm by hard-food stuff like scales. The cardiac and fundic regions exhibited large number tubular gastric glands with simple columnar epithelium. Surface cells of all three stomach regions stained positive for PAS staining. The intestine is without pyloric caeca and is divided into anterior and posterior region. Histologically it is characterized by simple columnar epithelium with brush border and numerous goblet cells throughout its length. Presence of large number microvilli on anterior and posterior intestine was noticeable. Intestinal goblet cells reacted positively to PAS, AB (pH 1) and AB (pH 2.5). Secretions of goblet cells are important for lubricating and protecting the epithelium. The results of present investigation improve the understanding of the digestive physiology of scale eaters in general and P. khavalchor in particular. Overall, our data indicates that though P. khavalchor predominantly feeds on scale, the digestive physiology is adapted to support dual feeding habit (lepidophagy and carnivory).

Ultrashort pulse Kagome hollow-core photonic crystal fiber delivery for nonlinear optical imaging

We report ultrashort pulse delivery through a hypocycloid-core inhibited-coupling Kagome hollow-core photonic crystal fiber (HC-PCF). Undistorted 10 fs and 6.6 nJ pulses were launched through 1 m long fiber without fiber dispersion pre-compensation and 80% efficiency. The performance of this technology for biomedical imaging is demonstrated on a biological sample by incorporating the fiber into a two-photon excited fluorescence (TPEF) laser scanning microscope (LSM) achieving a pulse width of 15 fs at the sample location. To the best of our knowledge, this is the first report on undistorted TPEF imaging in a LSM with 15 fs pulses delivered through a 1 m long Kagome HC-PCF with high throughput.

Short-term consumption of a high-fat diet increases host susceptibility to Listeria monocytogenes infection

BACKGROUND

A westernized diet comprising a high caloric intake from animal fats is known to influence the development of pathological inflammatory conditions. However, there has been relatively little focus upon the implications of such diets for the progression of infectious disease. Here, we investigated the influence of a high-fat (HF) diet upon parameters that influence Listeria monocytogenes infection in mice.

RESULTS

We determined that short-term administration of a HF diet increases the number of goblet cells, a known binding site for the pathogen, in the gut and also induces profound changes to the microbiota and promotes a pro-inflammatory gene expression profile in the host. Host physiological changes were concordant with significantly increased susceptibility to oral L. monocytogenes infection in mice fed a HF diet relative to low fat (LF)- or chow-fed animals. Prior to Listeria infection, short-term consumption of HF diet elevated levels of Firmicutes including Coprococcus, Butyricicoccus, Turicibacter and Clostridium XIVa species. During active infection with L. monocytogenes, microbiota changes were further exaggerated but host inflammatory responses were significantly downregulated relative to Listeria-infected LF- or chow-fed groups, suggestive of a profound tempering of the host response influenced by infection in the context of a HF diet. The effects of diet were seen beyond the gut, as a HF diet also increased the sensitivity of mice to systemic infection and altered gene expression profiles in the liver.

CONCLUSIONS

We adopted a systems approach to identify the effects of HF diet upon L. monocytogenes infection through analysis of host responses and microbiota changes (both pre- and post-infection). Overall, the results indicate that short-term consumption of a westernized diet has the capacity to significantly alter host susceptibility to L. monocytogenes infection concomitant with changes to the host physiological landscape. The findings suggest that diet should be a consideration when developing models that reflect human infectious disease.

Dietary fiber sources and non-starch polysaccharide-degrading enzymes modify mucin expression and the immune profile of the swine ileum

Due to their complex chemical and physical properties, the effects and mechanisms of action of natural sources of dietary fiber on the intestine are unclear. Pigs are commonly fed high-fiber diets to reduce production costs and non-starch polysaccharide (NSP)-degrading enzymes have been used to increase fiber digestibility. We evaluated the expression of mucin 2 (MUC2), presence of goblet cells, and ileal immune profile of pigs housed individually for 28 days and fed either a low fiber diet based on corn-soybean meal (CSB, n = 9), or two high fiber diets formulated adding 40% corn distillers' dried grains with solubles (DDGS, n = 9) or 30% wheat middlings (WM, n = 9) to CSB-based diet. Pigs were also fed those diets supplemented with a NSP enzymes mix (E) of xylanase, β-glucanase, mannanase, and galactosidase (n = 8, 10, and 9 for CSB+E, DDGS+E and WM+E, respectively). Feeding DDGS and WM diets increased ileal MUC2 expression compared with CSB diet, and this effect was reversed by the addition of enzymes. There were no differences in abundance of goblet cells among treatments. In general, enzyme supplementation increased gene expression and concentrations of IL-1β, and reduced the concentrations of IL-4, IL-17A and IL-11. The effects of diet-induced cytokines on modulating intestinal MUC2 were assessed in vitro by treating mouse and swine enteroids with 1 ng/ml of IL-4 and IL-1β. In accordance with previous studies, treatment with Il-4 induced Muc2 and expansion of goblet cells in mouse enteroids. However, swine enteroids did not change MUC2 expression or number of goblet cells when treated with IL-4 or IL-1β. Our results suggest that mucin and immune profile are regulated by diet in the swine intestine, but by mechanisms different to mouse, emphasizing the need for using appropriate models to study responses to dietary fiber in swine.

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

BACKGROUND & AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

A revised airway epithelial hierarchy includes CFTR-expressing ionocytes

The airways of the lung are the primary sites of disease in asthma and cystic fibrosis. Here we study the cellular composition and hierarchy of the mouse tracheal epithelium by single-cell RNA-sequencing (scRNA-seq) and in vivo lineage tracing. We identify a rare cell type, the Foxi1+ pulmonary ionocyte; functional variations in club cells based on their location; a distinct cell type in high turnover squamous epithelial structures that we term 'hillocks'; and disease-relevant subsets of tuft and goblet cells. We developed 'pulse-seq', combining scRNA-seq and lineage tracing, to show that tuft, neuroendocrine and ionocyte cells are continually and directly replenished by basal progenitor cells. Ionocytes are the major source of transcripts of the cystic fibrosis transmembrane conductance regulator in both mouse (Cftr) and human (CFTR). Knockout of Foxi1 in mouse ionocytes causes loss of Cftr expression and disrupts airway fluid and mucus physiology, phenotypes that are characteristic of cystic fibrosis. By associating cell-type-specific expression programs with key disease genes, we establish a new cellular narrative for airways disease.

Antibiotics promote the sampling of luminal antigens and bacteria via colonic goblet cell associated antigen passages

Bacterial translocation is defined as the passage of live bacteria from the gut lumen to distant sites. Gut commensal bacteria translocation has been attributed to 'leakiness', or 'barrier breach' of the intestinal epithelium, allowing live bacteria to cross an inappropriately permeable barrier and disseminate to distant sites. Alternatively, studies suggest dendritic cells directly capture luminal commensal bacteria and transport them to distant sites in the steady-state by extending dendrites between epithelial cells into the lumen. Recently we identified translocation of commensal gut bacteria following antibiotics was associated with the formation of goblet cell associated antigen passages (GAPs) in the colon and dependent upon goblet cells (GCs). The translocation of native gut commensal bacteria resulted in low-level inflammatory responses and potentiated mucosal damage in response to concurrent epithelial injury. Here we extend these observations and demonstrate properties of colonic GAPs and observations supporting their priority in the translocation of colonic commensal bacteria.

A xenogeneic-free system generating functional human gut organoids from pluripotent stem cells

Functional intestines are composed of cell types from all 3 primary germ layers and are generated through a highly orchestrated and serial developmental process. Directed differentiation of human pluripotent stem cells (hPSCs) has been shown to yield gut-specific cell types; however, these structures do not reproduce critical functional interactions between cell types of different germ layers. Here, we developed a simple protocol for the generation of mature functional intestinal organoids from hPSCs under xenogeneic-free conditions. The stem cell-derived gut organoids produced here were found to contain distinct types of intestinal cells, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells, that were derived from all 3 germ layers; moreover, they demonstrated intestinal functions, including peptide absorption, and showed innervated bowel movements in response to stimulation with histamine and anticholinergic drugs. Importantly, the gut organoids obtained using this xenogeneic-free system could be stably maintained in culture for prolonged periods and were successfully engrafted in vivo. Our xenogeneic-free approach for generating gut organoids from hPSCs provides a platform for studying human intestinal diseases and for pharmacological testing.

Effects of Quercetin Treatment on Epithelium-derived Cytokines and Epithelial Cell Apoptosis in Allergic Airway Inflammation Mice Model

Quercetin is a dietary flavonoid which has anti-inflammatory effects. This study aimed to evaluate the influence of quercetin on histopathological aspects and airway epithelium in  allergic airway  inflammation mice model. Twenty-eight BALB/c mice were randomly divided into four groups: Group I (control), Group II (untreated mice with allergic airway inflammation), Group III (allergic airway inflammation quercetin-treated [16mg/kg/day]), Group IV (allergic airway inflammation dexamethasone-treated [1mg/kg/day]). Ovalbumin was administered intraperitoneally and via inhalation to achieve allergic airway inflammation mice model and treatments were also given intraperitoneally. Epithelium thickness, subepithelial smooth muscle thickness, number of mast and goblet cells, and basement membrane thickness were examined on samples isolated from lung. Immunohistochemical evaluationof lung tissues was performed using  IL-25, IL-33, thymic stromal lymphopoietin (TSLP), terminal deoxynucleotidyl transferase-mediated dUTP nick endlabeling (TUNEL) and cysteine-dependent aspartate-specific proteases(caspase)-3 antibodies. IL-4, IL-25, IL-33, TSLP were quantified in bronchoalveolar lavage (BAL) and OVAspecific IgE levels was measured in serum by standard ELISA protocols. IL-25, IL-33, thymic stromal lymphopoietin (TSLP) and cysteine-dependent aspartate-specific proteases (caspase)-3. Quercetin treatment led to lower epithelial thickness, subepithelial smooth muscle thickness, goblet and mast cell numbers compared to untreated  mice with allergic airway inflammation (p<0.05). However, quercetin treatment was not effective on improving basal membane thickness. Immunohistochemical scores of IL-25, IL-33, TSLP, caspase-3 and TUNEL were lower in quercetin-treated mice  t compared to untreated mice with allergic airway inflammation (p<0.05). IL-4, IL-25, IL-33, TSLP levels in BAL and OVA-specific IgE in serum were lower in quercetin treated mice compared to untreated mice (p<0.05). These findings suggest that quercetin improves chronic histopathological changes except basal membrane thickness in lung tissue and its beneficial effects on inflammation might be related to modulating epithelium derived cytokines and epithelial apoptosis.

Intestinal epithelial tuft cells initiate type 2 mucosal immunity to helminth parasites

Helminth parasitic infections are a major global health and social burden. The host defence against helminths such as Nippostrongylus brasiliensis is orchestrated by type 2 cell-mediated immunity. Induction of type 2 cytokines, including interleukins (IL) IL-4 and IL-13, induce goblet cell hyperplasia with mucus production, ultimately resulting in worm expulsion. However, the mechanisms underlying the initiation of type 2 responses remain incompletely understood. Here we show that tuft cells, a rare epithelial cell type in the steady-state intestinal epithelium, are responsible for initiating type 2 responses to parasites by a cytokine-mediated cellular relay. Tuft cells have a Th2-related gene expression signature and we demonstrate that they undergo a rapid and extensive IL-4Rα-dependent amplification following infection with helminth parasites, owing to direct differentiation of epithelial crypt progenitor cells. We find that the Pou2f3 gene is essential for tuft cell specification. Pou2f3(-/-) mice lack intestinal tuft cells and have defective mucosal type 2 responses to helminth infection; goblet cell hyperplasia is abrogated and worm expulsion is compromised. Notably, IL-4Rα signalling is sufficient to induce expansion of the tuft cell lineage, and ectopic stimulation of this signalling cascade obviates the need for tuft cells in the epithelial cell remodelling of the intestine. Moreover, tuft cells secrete IL-25, thereby regulating type 2 immune responses. Our data reveal a novel function of intestinal epithelial tuft cells and demonstrate a cellular relay required for initiating mucosal type 2 immunity to helminth infection.

Histological and Ultrastructural Studies on the Conjunctiva of the Barred Owl (Strix varia)

This report is the first characterization of the histology and ultrastructure of the barred owl conjunctiva. The inferior eyelid was dominated by a large disk-shaped plate covered by a non-keratinized stratified squamous or cuboidal epithelium of variable thickness. The apical surface of the plate epithelium varied from flat to long microvilli or even short cytoplasmic extensions similar to those seen in the third eyelid. All specimens had a few goblet cells filled with mucous secretory granules in the plate region. The underlying connective tissue was a dense fibroelastic stroma. Eosinophils were surprisingly common in the epithelial layer and underlying connective tissue in the plate and more distal orbital mucosal region. The orbital mucosa contained goblet cells with heterogeneous glycosylation patterns. The leading edge and marginal plait of the third eyelid are designed to collect fluid and particulate matter as they sweep across the surface of the eye. The palpebral conjunctival surface of the third eyelid was covered by an approximately five-cell-deep stratified squamous epithelium without goblet cells. The bulbar surface of the third eyelid was a bilayer of epithelial cells whose superficial cells have elaborate cytoplasmic tapering extensions reaching out 25 μm. Narrow cytofilia radiated outwards up to an additional 15–20 μm from the cytoplasmic extensions. Lectin labeling demonstrated heterogeneous glycosylation of the apical membrane specializations but only small amounts of glycoprotein-filled secretory granules in the third eyelid.

Three cheers for the goblet cell: maintaining homeostasis in mucosal epithelia

Many organs throughout the body maintain epithelial homeostasis by employing a mucosal barrier which acts as a lubricant and helps to preserve a near-sterile epithelium. Goblet cells are largely responsible for secreting components of this mucosal barrier and represent a major cellular component of the innate defense system. In this review we summarize what is known about the signaling pathways that control goblet cell differentiation in the intestine, the lung, and the ocular surface, and we discuss a novel functional role for goblet cells in mucosal epithelial immunology. We highlight the cell type-specificity of the circuitry regulating goblet cell differentiation and shed light on how changes to these pathways lead to altered goblet cell function, a prominent feature of mucosa-associated diseases.

Detection and density estimation of goblet cells in confocal endoscopy for the evaluation of celiac disease

Celiac Disease (CD) is an immune-mediated enteropathy, diagnosed in the clinical practice by intestinal biopsy and the concomitant presence of a positive celiac serology. Confocal Laser Endomicroscopy (CLE) allows skilled and trained experts to potentially perform in vivo virtual histology of small-bowel mucosa. In particular, it allows the qualitative evaluation of mucosa alteration such as a decrease in goblet cells density, presence of villous atrophy or crypt hypertrophy. We present a semi-automatic computer-based method for the detection of goblet cells from confocal endoscopy images, whose density changes in case of pathological tissue. After a manual selection of a suitable region of interest, the candidate columnar and goblet cells' centers are first detected and the cellular architecture is estimated from their position using a Voronoi diagram. The region within each Voronoi cell is then analyzed and classified as goblet cell or other. The results suggest that our method is able to detect and label goblet cells immersed in a columnar epithelium in a fast, reliable and automatic way. Accepting 0.44 false positives per image, we obtain a sensitivity value of 90.3%. Furthermore, estimated and real goblet cell densities are comparable (error: 9.7 ± 16.9%, correlation: 87.2%, R(2) = 76%).

Ocular surface reconstruction with a tissue-engineered nasal mucosal epithelial cell sheet for the treatment of severe ocular surface diseases

Severe ocular surface diseases (OSDs) with severe dry eye can be devastating and are currently some of the most challenging eye disorders to treat. To investigate the feasibility of using an autologous tissue-engineered cultivated nasal mucosal epithelial cell sheet (CNMES) for ocular surface reconstruction, we developed a novel technique for the culture of nasal mucosal epithelial cells expanded ex vivo from biopsy-derived human nasal mucosal tissues. After the protocol, the CNMESs had 4-5 layers of stratified, well-differentiated cells, and we successfully generated cultured epithelial sheets, including numerous goblet cells. Immunohistochemistry confirmed the presence of keratins 3, 4, and 13; mucins 1, 16, and 5AC; cell junction and basement membrane assembly proteins; and stem/progenitor cell marker p75 in the CNMESs. We then transplanted the CNMESs onto the ocular surfaces of rabbits and confirmed the survival of this tissue, including the goblet cells, up to 2 weeks. The present report describes an attempt to overcome the problems of treating severe OSDs with the most severe dry eye by treating them using tissue-engineered CNMESs to supply functional goblet cells and to stabilize and reconstruct the ocular surface. The present study is a first step toward assessing the use of tissue-engineered goblet-cell transplantation of nonocular surface origin for ocular surface reconstruction.

Estradiol increases mucus synthesis in bronchial epithelial cells

Airway epithelial mucus hypersecretion and mucus plugging are prominent pathologic features of chronic inflammatory conditions of the airway (e.g. asthma and cystic fibrosis) and in most of these conditions, women have worse prognosis compared with male patients. We thus investigated the effects of estradiol on mucus expression in primary normal human bronchial epithelial cells from female donors grown at an air liquid interface (ALI). Treatment with estradiol in physiological ranges for 2 weeks caused a concentration-dependent increase in the number of PAS-positive cells (confirmed to be goblet cells by MUC5AC immunostaining) in ALI cultures, and this action was attenuated by estrogen receptor beta (ER-β) antagonist. Protein microarray data showed that nuclear factor of activated T-cell (NFAT) in the nuclear fraction of NHBE cells was increased with estradiol treatment. Estradiol increased NFATc1 mRNA and protein in ALI cultures. In a human airway epithelial (1HAE₀) cell line, NFATc1 was required for the regulation of MUC5AC mRNA and protein. Estradiol also induced post-translational modification of mucins by increasing total fucose residues and fucosyltransferase (FUT-4, -5, -6) mRNA expression. Together, these data indicate a novel mechanism by which estradiol increases mucus synthesis in the human bronchial epithelium.

Morphology and ciliary motion of mucosa in the Eustachian tube of neonatal and adult gerbils

The Eustachian tube is a small canal that connects the tympanic cavity with the nasal part of the pharynx. The epithelial lining of the Eustachian tube contains a ciliated columnar epithelium at the tympanic cavity and a pseudostratified, ciliated columnar epithelium with goblet cells near the pharynx. The tube serves to equalize air pressure across the eardrum and drains mucus away from the middle ear into the nasopharynx. Blockage of the Eustachian tube is the most common cause of all forms of otitis media, which is common in children. In the present study, we examined the epithelial lining of the Eustachian tube in neonatal and adult gerbils, with a focus on the morphological and functional development of ciliated cells in the mucosa. The length of the tube is ∼8.8 mm in adult gerbils. Scanning electron microscopy showed that the mucosal member near the pharyngeal side contains a higher density of ciliated cells and goblet cells than that near the tympanic side. The cilia beat frequency is 11 Hz. During development, the length of the Eustachian tube increased significantly between postnatal day 1 (P1) and P18. Scanning electron microscopy showed that the mucosa contained a high density of ciliated cells with a few goblet cells at P1. The density of ciliated cells decreased while the density of goblet cells increased during development. At P18, the mucosa appeared to be adult-like. Interestingly, the ciliary beat frequency measured from ciliated cells at P1 was not statistically different from that measured from adult animals. Our study suggests that the Eustachian tube undergoes significant anatomical and histological changes between P1 and P18. The tube is morphologically and functionally mature at P18, when the auditory function (sensitivity and frequency selectivity) is mature in this species.

Vitrified collagen-based conjunctival equivalent for ocular surface reconstruction

The main functions of the conjunctiva, an essential part of the ocular surface, are to maintain the equilibrium of the tear film and to protect the eye. Upon injuries, the prerequisite to successful ocular surface repair is conjunctival reconstruction. Tissue engineering techniques, including transplantation of autografts, amniotic membranes and numerous synthetic/natural materials, have been developed. However, none of these strategies is completely satisfactory due to lack of goblet cell repopulation, poor mechanical properties or non-standardized preparation procedure. Here, we cultured conjunctival epithelial cells on vitrified collagen membranes and developed a tissue equivalent for repairing damaged conjunctiva. Optimized vitrified collagen has superior mechanical and optical properties to previous biomaterials for ocular surface application, and its unique fibrillar structure significantly benefited conjunctival epithelial cell growth and the phenotypic development in vitro. In a rabbit model, vitrified collagen greatly promoted conjunctival regeneration with rapid re-epithelization, sufficient repopulation of goblet cells and minimized fibrosis and wound contracture, proved by gene expression analyses and histological staining. In conclusion, we have demonstrated the potential suitability of utilizing vitrified collagen-based tissue equivalent in ocular surface reconstruction.

Lineage-specific expression of bestrophin-2 and bestrophin-4 in human intestinal epithelial cells

Intestinal epithelial cells (IECs) regulate the absorption and secretion of anions, such as HCO3^- or Cl^-. Bestrophin genes represent a newly identified group of calcium-activated Cl^- channels (CaCCs). Studies have suggested that, among the four human bestrophin-family genes, bestrophin-2 (BEST2) and bestrophin-4 (BEST4) might be expressed within the intestinal tissue. Consistently, a study showed that BEST2 is expressed by human colonic goblet cells. However, their precise expression pattern along the gastrointestinal tract, or the lineage specificity of the cells expressing these genes, remains largely unknown. Here, we show that BEST2 and BEST4 are expressed in vivo, each in a distinct, lineage-specific manner, in human IECs. While BEST2 was expressed exclusively in colonic goblet cells, BEST4 was expressed in the absorptive cells of both the small intestine and the colon. In addition, we found that BEST2 expression is significantly down-regulated in the active lesions of ulcerative colitis, where goblet cells were depleted, suggesting that BEST2 expression is restricted to goblet cells under both normal and pathologic conditions. Consistently, the induction of goblet cell differentiation by a Notch inhibitor, LY411575, significantly up-regulated the expression of not BEST4 but BEST2 in MUC2-positive HT-29 cells. Conversely, the induction of absorptive cell differentiation up-regulated the expression of BEST4 in villin-positive Caco-2 cells. In addition, we found that the up- or down-regulation of Notch activity leads to the preferential expression of either BEST4 or BEST2, respectively, in LS174T cells. These results collectively confirmed that BEST2 and BEST4 could be added to the lineage-specific genes of humans IECs due to their abilities to clearly identify goblet cells of colonic origin and a distinct subset of absorptive cells, respectively.

Fbw7 repression by hes5 creates a feedback loop that modulates Notch-mediated intestinal and neural stem cell fate decisions

FBW7 is a crucial component of an SCF-type E3 ubiquitin ligase, which mediates degradation of an array of different target proteins. The Fbw7 locus comprises three different isoforms, each with its own promoter and each suspected to have a distinct set of substrates. Most FBW7 targets have important functions in developmental processes and oncogenesis, including Notch proteins, which are functionally important substrates of SCF(Fbw7). Notch signalling controls a plethora of cell differentiation decisions in a wide range of species. A prominent role of this signalling pathway is that of mediating lateral inhibition, a process where exchange of signals that repress Notch ligand production amplifies initial differences in Notch activation levels between neighbouring cells, resulting in unequal cell differentiation decisions. Here we show that the downstream Notch signalling effector HES5 directly represses transcription of the E3 ligase Fbw7β, thereby directly bearing on the process of lateral inhibition. Fbw7(Δ/+) heterozygous mice showed haploinsufficiency for Notch degradation causing impaired intestinal progenitor cell and neural stem cell differentiation. Notably, concomitant inactivation of Hes5 rescued both phenotypes and restored normal stem cell differentiation potential. In silico modelling suggests that the NICD/HES5/FBW7β positive feedback loop underlies Fbw7 haploinsufficiency. Thus repression of Fbw7β transcription by Notch signalling is an essential mechanism that is coupled to and required for the correct specification of cell fates induced by lateral inhibition.

Chronic IL9 and IL-13 exposure leads to an altered differentiation of ciliated cells in a well-differentiated paediatric bronchial epithelial cell model

Asthma is a chronic inflammatory disease characterised by airways remodelling. In mouse models IL-9 and IL-13 have been implicated in airways remodelling including mucus hypersecretion and goblet cell hyperplasia. Their role, especially that of IL-9, has been much less studied in authentic human ex vivo models of the bronchial epithelium from normal and asthmatic children. We assessed the effects of IL-9, IL-13 and an IL-9/IL-13 combination, during differentiation of bronchial epithelial cells from normal (n = 6) and asthmatic (n = 8) children. Cultures were analysed for morphological markers and factors associated with altered differentiation (MUC5AC, SPDEF and MMP-7). IL-9, IL-9/IL-13 combination and IL-13 stimulated bronchial epithelial cells from normal children had fewer ciliated cells [14.8% (SD 8.9), p = 0.048, 12.4 (SD 6.1), p = 0.016 and 7.3% (SD 6.6), p = 0.031] respectively compared with unstimulated [(21.4% (SD 9.6)]. IL-9 stimulation had no effect on goblet cell number in either group whereas IL-9/IL-13 combination and IL-13 significantly increased goblet cell number [24.8% (SD 8.8), p = 0.02), 32.9% (SD 8.6), p = 0.007] compared with unstimulated normal bronchial cells [(18.6% (SD 6.2)]. All stimulations increased MUC5AC mRNA in bronchial epithelial cells from normal children and increased MUC5AC mucin secretion. MMP-7 localisation was dysregulated in normal bronchial epithelium stimulated with Th2 cytokines which resembled the unstimulated bronchial epithelium of asthmatic children. All stimulations resulted in a significant reduction in transepithelial electrical resistance values over time suggesting a role in altered tight junction formation. We conclude that IL-9 does not increase goblet cell numbers in bronchial epithelial cell cultures from normal or asthmatic children. IL-9 and IL-13 alone and in combination, reduce ciliated cell numbers and transepithelial electrical resistance during differentiation of normal epithelium, which clinically could inhibit mucociliary clearance and drive an altered repair mechanism. This suggests an alternative role for IL-9 in airways remodelling and reaffirms IL-9 as a potential therapeutic target.

Bacteria regulate intestinal epithelial cell differentiation factors both in vitro and in vivo

BACKGROUND

The human colon harbours a plethora of bacteria known to broadly impact on mucosal metabolism and function and thought to be involved in inflammatory bowel disease pathogenesis and colon cancer development. In this report, we investigated the effect of colonic bacteria on epithelial cell differentiation factors in vitro and in vivo. As key transcription factors we focused on Hes1, known to direct towards an absorptive cell fate, Hath1 and KLF4, which govern goblet cell.

METHODS

Expression of the transcription factors Hes1, Hath1 and KLF4, the mucins Muc1 and Muc2 and the defensin HBD2 were measured by real-time PCR in LS174T cells following incubation with several heat-inactivated E. coli strains, including the probiotic E. coli Nissle 1917+/- flagellin, Lactobacilli and Bifidobacteria. For protein detection Western blot experiments and chamber-slide immunostaining were performed. Finally, mRNA and protein expression of these factors was evaluated in the colon of germfree vs. specific pathogen free vs. conventionalized mice and colonic goblet cells were counted.

RESULTS

Expression of Hes1 and Hath1, and to a minor degree also of KLF4, was reduced by E. coli K-12 and E. coli Nissle 1917. In contrast, Muc1 and HBD2 expression were significantly enhanced, independent of the Notch signalling pathway. Probiotic E. coli Nissle 1917 regulated Hes1, Hath1, Muc1 and HBD2 through flagellin. In vivo experiments confirmed the observed in vitro effects of bacteria by a diminished colonic expression of Hath1 and KLF4 in specific pathogen free and conventionalized mice as compared to germ free mice whereas the number of goblet cells was unchanged in these mice.

CONCLUSIONS

Intestinal bacteria influence the intestinal epithelial differentiation factors Hes1, Hath1 and KLF4, as well as Muc1 and HBD2, in vitro and in vivo. The induction of Muc1 and HBD2 seems to be triggered directly by bacteria and not by Notch.

Ghrelin effect on nutritional indices, midgut and fat body of Lymantria dispar L. (Lymantriidae)

Ghrelin is a 28-amino acid peptide that has significant effects on appetite and growth in humans and animals. The aim of this study was to examine 4th instar larvae of the pest insect Lymantria dispar L. after ghrelin treatment. Parameters included changes in nutritional indices (efficiency of conversion of ingested food, efficiency of conversion of digested food, approximate digestibility); midgut and fat body mass; total proteases, trypsin and leucine aminopeptidase activities in the midgut; number, height and width of columnar and goblet cells and their nuclei in the midgut epithelium and detection of ghrelin-like immunoreactivity in the midgut tissue. Four subpicomolar injections of ghrelin (0.3pmol) or physiological saline (control) were applied every 24h. The nutritional indices were higher in the ghrelin treated than in the control group. Ghrelin treatment was also associated with elevation of midgut mass, induced digestive enzyme activities, increased fat body mass and morphometric changes in columnar and goblet cells. This is the first report of the presence of ghrelin-like hormone in endocrine cells of an insect midgut. Such information provides additional evidence for application of this relatively simple model system in the future studies of the mechanisms underlying of digestion and energy balance in more complex organisms.

Fast renewal of the distal colonic mucus layers by the surface goblet cells as measured by in vivo labeling of mucin glycoproteins

The enormous bacterial load and mechanical forces in colon create a special requirement for protection of the epithelium. In the distal colon, this problem is largely solved by separation of the bacteria from the epithelium by a firmly attached inner mucus layer. In addition, an outer mucus layer entraps bacteria to be cleared by distal transport. The mucus layers contain a network of Muc2 mucins as the main structural component. Here, the renewal rate of the inner protective mucus layer was studied as well as the production and secretion of Muc2 mucin in the distal colon. This was performed by intraperitoneal injection of N-azidoacetyl-galactosamine (GalNAz) that was in vivo incorporated during biosynthesis of O-glycosylated glycoproteins. The only gel-forming mucin produced in the colon is the Muc2 mucin and as it carries numerous O-glycans, the granulae of the goblet cells producing Muc2 mucin were intensely stained. The GalNAz-labeled glycoproteins were first observed in the Golgi apparatus of most cells. Goblet cells in the luminal surface epithelium had the fastest biosynthesis of Muc2 and secreted material already three hours after labeling. This secreted GalNAz-labeled Muc2 mucin formed the inner mucus layer. The goblet cells along the crypt epithelium accumulated labeled mucin vesicles for a longer period and secretion of labeled Muc2 mucin was first observed after 6 to 8 h. This study reveals a fast turnover (1 h) of the inner mucus layer in the distal colon mediated by goblet cells of the luminal surface epithelium.

Regulation of mouse intestinal L cell progenitors proliferation by the glucagon family of peptides

Glucagon like peptide-1 (GLP-1) and GLP-2 are hormones secreted by intestinal L cells that stimulate glucose-dependent insulin secretion and regulate intestinal growth, respectively. Mice with deletion of the glucagon receptor (Gcgr) have high levels of circulating GLP-1 and GLP-2. We sought to determine whether the increased level of the glucagon-like peptides is due to L cell hyperplasia. We found, first, that high levels of the glucagon-like peptides increase L cell number but does not affect the number of other intestinal epithelial cell types. Second, a large proportion of ileal L cells of Gcgr(-/-) mice coexpressed glucose-dependent insulinotropic peptide (GIP). Cells coexpressing GIP and GLP-1 are termed LK cells. Third, the augmentation in L cell number was due to a higher rate of proliferation of L cell progenitors rather than to the entrance of mature L cells into the cell cycle. Fourth, a high concentration of the glucagon-like peptides in the circulation augmented the mRNA levels of transcription factors expressed by late but not early enteroendocrine progenitors. Fifth, the administration of exendin 9-39, a GLP-1 receptor antagonist, resulted in a decrease in the rate of L cell precursor proliferation. Finally, we determined that L cells do not express the GLP-1 receptor, suggesting that the effect of GLP-1 is mediated by paracrine and/or neuronal signals. Our results suggest that GLP-1 plays an important role in the regulation of L cell number.

Theaflavins extracted from black tea inhibit airway mucous hypersecretion induced by cigarette smoke in rats

Theaflavins isolated from black tea have been used in studies on the prevention of tumor growth. The aim of this study was to investigate whether treatment with theaflavins influences the mucus hypersecretion induced by cigarette smoke in the lungs of experimental rats. Firstly, cigarette smoke was aerosolized using a machine designed for inhalation by rats. The rats were divided into the negative control group, the cigarette smoke inhalation group, the theaflavins (TFs) treatment group, and the TFs +cigarette smoke inhalation group. The animals were sacrificed on day 60 of the experiment. Secondly, the rats were treated with theaflavins at different doses via a gastric tube and sacrificed on day 30. The changes in the levels of mucin 5AC (MUC5AC) and epidermal growth factor receptor (EGFR) in the airway were evaluated. Cigarette smoke induced a significant increase in the levels of MUC5AC and EGFR in all groups. These increases could be reversed by intragastric administration of theaflavins. The effect was more pronounced with the duration of treatment and coincided with a decrease in the expression of both targets. The rats showed various degrees of reduction in the expression of these parameters, which correlated with the theaflavin dose. TFs could inhibit the activation of EGFR, decrease the level of MUC5AC, and relieve airway mucous hypersecretion via the EGFR signaling pathway. These effects correlated directly with the duration of action and the dosage. In the future, oral theaflavins might be valuable in the treatment of chronic airway inflammation.

[Structural and functional characteristic of rat jejunum after long-term exposure to alcohol]

Histological, morphometric and histochemical analysis of the mucous membrane of the jejunum was performed in 40 adult male rats after alcohol intoxication of 2,4 and 6 month duration. It was shown that alcohol intoxication for 2 months resulted in mucosal hypertrophy of the jejunum with a significant increase in the number of goblet cells. After 4 months, there was a tendency for the inhibition of the mitotic activity of enterocytes with the decrease of their regeneration activity. Atrophy of the mucous membrane was aggravated by the 6th month. Morphological changes in the mucous membrane were associated with the inhibition of alkaline phosphatase activity in the enterocytes. Most pronounced decrease in the activity of the enzyme was detected in the cells located at the top of intestinal villi. Maximal enzyme activity inhibition was observed after 6 months.

Cdx regulates Dll1 in multiple lineages

Vertebrate Cdx genes encode homeodomain transcription factors related to caudal in Drosophila. The murine Cdx homologues Cdx1, Cdx2 and Cdx4 play important roles in anterior-posterior patterning of the embryonic axis and the intestine, as well as axial elongation. While our understanding of the ontogenic programs requiring Cdx function has advanced considerably, the molecular bases underlying these functions are less well understood. In this regard, Cdx1-Cdx2 conditional mutants exhibit abnormal somite formation, while loss of Cdx1-Cdx2 in the intestinal epithelium results in a shift in differentiation toward the Goblet cell lineage. The aim of the present study was to identify the Cdx-dependent mechanisms impacting on these events. Consistent with prior work implicating Notch signaling in these pathways, we found that expression of the Notch ligand Dll1 was reduced in Cdx mutants in both the intestinal epithelium and paraxial mesoderm. Cdx members occupied the Dll1 promoter both in vivo and in vitro, while genetic analysis indicated interaction between Cdx and Dll1 pathways in both somitogenesis and Goblet cell differentiation. These findings suggest that Cdx members operate upstream of Dll1 to convey different functions in two distinct lineages.

Zebrafish krüppel-like factor 4a represses intestinal cell proliferation and promotes differentiation of intestinal cell lineages

Background

Mouse krüppel-like factor 4 (Klf4) is a zinc finger-containing transcription factor required for terminal differentiation of goblet cells in the colon. However, studies using either Klf4^−/− mice or mice with conditionally deleted Klf4 in their gastric epithelia showed different results in the role of Klf4 in epithelial cell proliferation. We used zebrafish as a model organism to gain further understanding of the role of Klf4 in the intestinal cell proliferation and differentiation.

Methodology/Principal Findings

We characterized the function of klf4a, a mammalian klf4 homologue by antisense morpholino oligomer knockdown. Zebrafish Klf4a shared high amino acid similarities with human and mouse Klf4. Phylogenetic analysis grouped zebrafish Klf4a together with both human and mouse Klf4 in a branch with high bootstrap value. In zebrafish, we demonstrate that Klf4a represses intestinal cell proliferation based on results of BrdU incorporation, p-Histone 3 immunostaining, and transmission electron microscopy analyses. Decreased PepT1 expression was detected in intestinal bulbs of 80- and 102-hours post fertilization (hpf) klf4a morphants. Significant reduction of alcian blue-stained goblet cell number was identified in intestines of 102- and 120-hpf klf4a morphants. Embryos treated with γ-secretase inhibitor showed increased klf4a expression in the intestine, while decreased klf4a expression and reduction in goblet cell number were observed in embryos injected with Notch intracellular domain (NICD) mRNA. We were able to detect recovery of goblet cell number in 102-hpf embryos that had been co-injected with both klf4a and Notch 1a NICD mRNA.

Conclusions/Significance

This study provides in vivo evidence showing that zebrafih Klf4a is essential for the repression of intestinal cell proliferation. Zebrafish Klf4a is required for the differentiation of goblet cells and the terminal differentiation of enterocytes. Moreover, the regulation of differentiation of goblet cells in zebrafish intestine by Notch signaling at least partially mediated through Klf4a.

Genetic evidence that intestinal Notch functions vary regionally and operate through a common mechanism of Math1 repression

Notch signaling is active in many sites, and its diverse activities must require tissue-specific intermediaries, which are largely unknown. In the intestinal epithelium, Notch promotes crypt cell proliferation and inhibits goblet cell differentiation. Pharmacologic studies suggest that the latter effect occurs through the transcription factor Math1/Atoh1, which specifies all intestinal secretory cells. We tested this hypothesis using mouse mutants. Genetic loss of the Notch effector RBP-Jκ alone increases all intestinal secretory lineages, with variation between proximal and distal gut segments. This secretory cell excess observed with RBP-Jκ loss was blocked in the absence of Math1 in RBP-Jκ(Fl/Fl);Math1(Fl/Fl);Villin-Cre((ER-T2)) mice. Loss of both factors also restored progenitor replication, proving that Math1 is epistatic to Notch signaling in both secretory cell differentiation and crypt cell proliferation. Investigating mechanisms downstream of Math1, we found that expression of the known Notch effector protein Hes1 was predictably lost in RBP-Jκ(-/-) mice but surprisingly recovered in RBP-Jκ;Math1 compound conditional mutants. Furthermore, the cell cycle inhibitors p27(Kip1) and p57(Kip2) were selectively overexpressed in duodenal and ileal crypts, respectively, in RBP-Jκ-deficient mice. Regional activation of these products was completely abrogated in the absence of Math1. Thus, all intestinal Notch effects channel through the tissue-restricted factor Math1, which promotes secretory differentiation and cell cycle exit by regionally distinct mechanisms. Our data further suggest that, besides transmitting Notch signals, the transcription factor Hes1 acts downstream of Math1 to regulate expression of cell cycle inhibitors and intestinal crypt cell replication.

[The observation of the inflamed cells in the mucosa at the medial site compare with that at the lateral site of the normal uncinate process]

OBJECTIVE

To determine the inflammatory cells in the mucosa at the medial aspect of the normal uncinate process compared with that on the protected lateral aspect of the normal uncinate process.

METHOD

The mucosa of 20 uncinate process from the nasal cavity of 17 patients with no evidence of sinus disease undergoing functional endoscopic sinus surgery were recruited for the study. The material was stained with HE, Chromotrope 2R, Alcian blue-periodic acid-schiff, Toluidine blue. Specimens were observed using an Olympus microscope.

RESULT

The number of mast cells and goblet cells were found to be higher on the lateral aspect of the normal uncinate process than on the medial aspect. The number of plasma cells was obviously different from that of lymphocytes. We did not found any eosinophils on either sides of uncinate process.

CONCLUSION

There are differences in the number of mast cells and goblet cells between the mucosa at the medial aspect of the normal uncinate process and the mucosa at the protected lateral aspect of the normal uncinate process.

Longitudinal cell formation in the entire human small intestine is correlated with the localization of Hath1 and Klf4

BACKGROUND

Double balloon endoscopy (DBE) enables the observation and collection of viable specimens from the entire intestine, thereby allowing more detailed investigation of how the structure and function of the human small intestine are regulated. The present study aimed to elucidate the regulation of cell formation in the human small intestine using biopsy specimens collected from an entire individual small intestine by DBE.

METHODS

The expression and the localization of representative genes for the differentiation program were analyzed in the entire small intestine of 10 patients. The functional correlation between Hath1 and Klf4 was analyzed in an intestinal cell line by using a Tet-On system.

RESULTS

In longitudinal cell formation in the small intestine, it was shown that goblet cells, but not Paneth cells, increased toward the ileum in each individual small intestine. Immunohistochemistry showed that Hath1-expressing cells migrated from the base of the crypt to the top of the villi in the terminal ileum, while Klf4-expressing cells migrated from the top of the villus, resulting in the colocalization of Hath1 and Klf4 in the terminal ileum. Coexpression of Hath1 and Klf4 upregulated the expression of phenotypic genes for goblet cells following the downregulation of those for Paneth cells.

CONCLUSIONS

Using mapping biopsy by DBE, we have demonstrated, for the first time, the molecular basis of the villus structure in the entire human small intestine in vivo. The present study showed that longitudinal cell formation was regulated by the colocalization of Hath1 and Klf4 that converted Paneth cell differentiation into goblet cell differentiation.