Goblet Cells In Small Intestine Research Articles

Induction of Sda-sialomucin and sulfated H-sulfomucin in mouse small intestinal mucosa by infection with parasitic helminth

Mucin is a major component of mucus on gastrointestinal mucosa. Mucin alteration in the host is considered to be the principal event for expulsion of intestinal helminths. However, it is unclear what mucin alterations are induced by various helminth infections. In this study, the alterations of mouse small intestinal mucin after infection with two nematodes, Nippostrongylus brasiliensis and Heligmosomoides polygyrus, which parasitize the jejunal epithelium, and a cestode, Vampirolepis nana, which parasitizes the ileal epithelium, were examined biochemically and histologically using two anti-mucin monoclonal antibodies (mAbs), HCM31 and PGM34, which recognize Sda antigen, NeuAcα2–3(GalNAcβ1–4)Galβ1-4GlcNAcβ-, and sulphated H type 2 antigen, Fucα1-2Galβ1-4GlcNAc(6SO3H)β-, respectively. The goblet cell mucins that reacted with HCM31 increased conspicuously on the jejunal mucosa concurrently with expulsion of N. brasiliensis. Increased levels of HCM31-reactive mucins were observed in the jejunal mucosa after H. polygyrus infection, despite the ongoing parasitism. Goblet cell mucins that reacted with PGM34 increased on the ileal mucosa during V. nana parasitism. Small intestinal goblet cells reacting with the two mAbs were not observed in non-infected mice, although sialomucins and sulfomucins were abundantly present. Additionally, the number of ileal goblet cells that reacted with the two mAbs was increased at the time of expulsion of heterophyid trematode. These results indicate that the type of specific acidic mucins expressed after infection varies among species of intestinal helminth, and, furthermore, that the relationship with worm expulsion is also different.

Fibroblast growth factor 10 alters the balance between goblet and Paneth cells in the adult mouse small intestine.

Intestinal epithelial cell renewal relies on the right balance of epithelial cell migration, proliferation, differentiation, and apoptosis. Intestinal epithelial cells consist of absorptive and secretory lineage. The latter is comprised of goblet, Paneth, and enteroendocrine cells. Fibroblast growth factor 10 (FGF10) plays a central role in epithelial cell proliferation, survival, and differentiation in several organs. The expression pattern of FGF10 and its receptors in both human and mouse intestine and their role in small intestine have yet to be investigated. First, we analyzed the expression of FGF10, FGFR1, and FGFR2, in the human ileum and throughout the adult mouse small intestine. We found that FGF10, FGFR1b, and FGFR2b are expressed in the human ileum as well as in the mouse small intestine. We then used transgenic mouse models to overexpress Fgf10 and a soluble form of Fgfr2b, to study the impact of gain or loss of Fgf signaling in the adult small intestine. We demonstrated that overexpression of Fgf10 in vivo and in vitro induces goblet cell differentiation while decreasing Paneth cells. Moreover, FGF10 decreases stem cell markers such as Lgr5, Lrig1, Hopx, Ascl2, and Sox9. FGF10 inhibited Hes1 expression in vitro, suggesting that FGF10 induces goblet cell differentiation likely through the inhibition of Notch signaling. Interestingly, Fgf10 overexpression for 3 days in vivo and in vitro increased the number of Mmp7/Muc2 double-positive cells, suggesting that goblet cells replace Paneth cells. Further studies are needed to determine the mechanism by which Fgf10 alters cell differentiation in the small intestine.

Colonic goblet cell intrinsic, Myd88 dependent, microbial sensing rapidly regulates antigen delivery to the lamina propria immune system (MUC4P.853)

Abstract The delivery of antigens across the intestinal epithelium is an early and critical event in homeostatic responses to innocuous antigens and inflammatory responses to potential pathogens. The factors and mechanisms regulating antigen delivery to the lamina propria (LP) immune system are largely unknown. We recently demonstrated when small intestinal goblet cells (GCs) secrete, they form goblet cell-associated antigen passages (GAPs) and deliver luminal antigens to LP dendritic cells (DCs). Here we report in the basal state, GAP formation is driven by acetylcholine (Ach) signaling via the muscarinic ACh receptor 4 (mAChR4) expressed by GCs. In contrast to conventionally housed mice, GAPs were present in the colon of mice with a reduced microbiota or altered microbial sensing. Formation of colonic GAPs in these mice was dependent upon mAChR4 signaling. Moreover, in mice with a reduced microbial load, luminal microbial stimuli inhibited GAP formation within minutes. In vitro studies revealed GC intrinsic sensing of the microbiota rapidly inhibited ACh induced GC secretion, and conditional deletion of Myd88 in GCs in conventionally housed mice resulted in the spontaneous formation of colonic GAPs, and the delivery of luminal antigen to colonic LP DCs. These findings identify a role for microbial sensing by colonic GCs to rapidly regulate antigen delivery to the LP immune system, and preventing delivery of luminal antigens when the luminal microbial load is abundant and complex.

Goblet cell-associated antigen passages are reduced during enteric infection (MUC4P.831)

Abstract The intestinal mucosa is continually exposed to foreign antigens derived from the diet, commensal bacteria, and pathogens. Regulating the exposure of the immune system to this broad array of antigens is crucial to ensure intestinal homeostasis and to respond appropriately to enteric infections. Using in vivo two-photon imaging of the intestine of live mice, we recently demonstrated that under steady state conditions a subset of small intestinal goblet cells (GCs) transport luminal antigens to CD103+ dendritic cells (DCs) by forming goblet cell-associated antigen passages (GAPs). To understand how enteric infection altered GCs and GAPs, we infected mice with wildtype fluorescently labeled Salmonella typhimurium and evaluated GCs and GAPs using fluorescence microscopy. Within hours of intraluminal exposure, Salmonella preferentially localized around and within GCs that had formed GAPs. 24 hours after oral Salmonella infection, a subset of GCs were found to be apoptotic, and 72 hours after infection, GAPs were significantly decreased beyond the level of GC apoptosis. Salmonella infection resulted in epithelial activation of the epidermal growth factor receptor (EGFR), a potential regulator of GC secretion and GAP formation. These observations indicate that GAPs may provide a portal of entry for pathogens, and that GAP formation is reduced following enteric infection potentially to avoid delivery of luminal antigen to lamina propria immune cells in a hostile environment.

Dietary Nickel Chloride Restrains the Development of Small Intestine in Broilers

The aim of this study was to determine the effects of dietary NiCl2 on the development of the small intestine in broilers by the methods of light microscopy, histochemistry and enzyme-linked immunosorbent assay. A total of 240 one-day-old avian broilers were divided into four groups and fed on a corn-soybean basal diet or the same basal diet supplemented with 300, 600 and 900 mg/kg of nickel chloride (NiCl2) for 42 days. Results showed that the small intestinal villus height, crypt depth and villus/crypt ratio were significantly decreased, and also the small intestinal goblet cells numbers and insulin-like growth factor-1 (IGF-1) and epidermal growth factor (EGF) contents were significantly decreased in the 300-, 600- and 900-mg/kg groups when compared with those of the control group. In conclusion, dietary NiCl2 in excess of 300 mg/kg reduced the villus height, crypt depth, the goblet cells population and the IGF-1 and EGF contents in the small intestine, indicating that the normal development and function of the small intestine were finally impaired in broilers. This study firstly provided the new experimental information for future studies on the effects of NiCl2 on the intestinal function in humans and other animals.

Luminal microbial sensing regulates colonic goblet cell associated antigen passages through the activation of p42/p44 MAPK and the EGFR (P3154)

Abstract The intestinal tract is full of proteins ranging in antigenicity from inert food antigens to potential pathogens and bacterial toxins. A major focus of mucosal immunology is to better understand how these antigens are acquired and introduced to the immune system. Using intravital two-photon imaging we recently showed that in conventionally housed mice, small intestinal goblet cells, but not colonic goblet cells, act as a route of antigen delivery to intestinal dendritic cells by forming goblet cell-associated antigen passages (GAPs), in a mechanism linked to goblet cell secretion. In contrast to conventionally housed mice, we observed that GAPs were present in the colon of germfree mice, mice given antibiotics, and, surprisingly, neonatal mice. We found that the activation of p44/p42 MAPK and EGFR in colonic goblet cells correlated with the presence of luminal microbiota and the ability to sense the flora via TLRs. Inhibition of either p42/p44 MAPK or EGFR allowed GAP formation to occur in the colon of SPF housed mice, and colonic GAPs in germfree mice were blocked by activation of the EGFR. These observations indicate that sensing the enteric flora inhibits colonic GAP formation. This regulation of antigen delivery would allow sampling of luminal antigens when the environment is permissive, such as in the homeostatic small intestine, but would prevent sampling luminal antigens in a hostile environment, such as the high microbial load in the colon or during infection.

Small Intestinal Goblet Cell Proliferation Induced by Ingestion of Soluble and Insoluble Dietary Fiber Is Characterized by An Increase in Sialylated Mucins in Rats1–3

The study aimed to examine the effects of insoluble and soluble fibers on mucin sialylation and sulfation in the small intestine. First, diets containing soluble [konjac mannan (KM), psyllium, or guar gum; 50 g/kg) or insoluble (polystyrene foam, wheat bran, or cornhusk; 80 g/kg) fiber were fed to rats for 13 d. The fiber-fed groups had more goblet cells in the ileum than the fiber-free control group. High-iron diamine/alcian blue staining showed more sialylated mucin-producing cells in the fiber-fed groups than in the control, whereas sulfated mucin-producing cells were fewer (insoluble fibers) or unchanged (soluble fibers). Second, feeding KM (50 g/kg) and beet fiber (BF) (80 g/kg) diets for 7 d yielded a higher ileum Siat4Cexpression than the control, butGal3ST2andGal3ST4expression was comparable. Luminal mucin content correlated with sialic acid (r= 0.96;P< 0.001) or sulfate (r= 0.62;P< 0.01), but the slope of the sialic acid-derived equation was greater than that of the sulfate-derived equation, indicating a preferred increase in sialylated mucins. Third, rats were fed the control diet for 10 d while receiving antibiotic treatment. Analysis of the luminal mucin showed that sialylated mucins were more vulnerable to bacterial degradation than sulfated mucins. Finally, a study of bromo-deoxyuridine incorporation in rats fed a BF diet indicated that goblet cell proliferation accompanied by increased sialylated mucin appeared to be related to accelerated ileal epithelial cell migration. We conclude that intestinal goblet cell responses to insoluble and soluble fibers are characterized by increases in sialylated mucin production.

Goblet cells deliver luminal antigen to CD103+ dendritic cells in the small intestine

The intestinal immune system is exposed to a mixture of foreign antigens from diet, commensal flora, and potential pathogens. Understanding how pathogen-specific immunity is elicited while avoiding inappropriate responses to the background of innocuous antigens is essential for understanding and treating intestinal infections and inflammatory diseases. The ingestion of protein antigen can induce oral tolerance, which is mediated in part by a subset of intestinal dendritic cells (DCs) that promote the development of regulatory T cells1. The lamina propria (LP) underlies the expansive single cell absorptive villous epithelium and contains a large population of DCs (CD11c+ CD11b+ MHCII+ cells) comprised of two predominant subsets; CD103+ CX3CR1− DCs, which promote IgA production, imprint gut homing on lymphocytes, and induce the development of regulatory T cells2–9, and CD103− CX3CR1+ DCs (with features of macrophages), which promote TNFα production, colitis, and the development of Th17 T cells5–7,10. However the mechanisms by which different intestinal LP-DC subsets capture luminal antigens in vivo remains largely unexplored. Using a minimally disruptive in vivo imaging approach we show that in the steady-state, small intestine goblet cells (GCs) function as passages delivering low molecular weight soluble antigens from the intestinal lumen to underlying CD103+ LP-DCs. The preferential delivery of antigens to DCs with tolerogenic properties implies a key role for this GC function in intestinal immune homeostasis.

Krüppel-like Factor 4 Regulates Intestinal Epithelial Cell Morphology and Polarity

Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor that plays a vital role in regulating cell lineage differentiation during development and maintaining epithelial homeostasis in the intestine. In normal intestine, KLF4 is predominantly expressed in the differentiated epithelial cells. It has been identified as a tumor suppressor in colorectal cancer. KLF4 knockout mice demonstrated a decrease in number of goblet cells in the colon, and conditional ablation of KLF4 from the intestinal epithelium led to altered epithelial homeostasis. However, the role of KLF4 in differentiated intestinal cells and colon cancer cells, as well as the mechanism by which it regulates homeostasis and represses tumorigenesis in the intestine is not well understood. In our study, KLF4 was partially depleted in the differentiated intestinal epithelial cells by a tamoxifen-inducible Cre recombinase. We found a significant increase in the number of goblet cells in the KLF4-deleted small intestine, suggesting that KLF4 is not only required for goblet cell differentiation, but also required for maintaining goblet cell numbers through its function in inhibiting cell proliferation. The number and position of Paneth cells also changed. This is consistent with the KLF4 knockout study using villin-Cre [1]. Through immunohistochemistry (IHC) staining and statistical analysis, we found that a stem cell and/or tuft cell marker, DCAMKL1, and a proliferation marker, Ki67, are affected by KLF4 depletion, while an enteroendocrine cell marker, neurotensin (NT), was not affected. In addition, we found KLF4 depletion altered the morphology and polarity of the intestinal epithelial cells. Using a three-dimensional (3D) intestinal epithelial cyst formation assay, we found that KLF4 is essential for cell polarity and crypt-cyst formation in human colon cancer cells. These findings suggest that, as a tumor suppressor in colorectal cancer, KLF4 affects intestinal epithelial cell morphology by regulating proliferation, differentiation and polarity of the cells.

The monoclonal antibody HCM31 specifically recognises the Sda tetrasaccharide in goblet cell mucin

Rat small intestinal goblet cell mucins reacting with monoclonal antibody HCM31 increase significantly during regeneration from experimental mucosal damage and at the period of expulsion of parasitic nematode, Nippostrongylus brasiliensis (N.b). The reduction in reactivity of HCM31 with mucin upon neuraminidase treatment, suggested that HCM31 recognizes sialylated oligosaccharide on mucin. HCM31-reactive sialomucins are therefore considered to play an important role in the physiological and pathological changes in the gastrointestinal mucosa. To determine the epitope for HCM31, oligosaccharide–alditols reacted with HCM31 were obtained from the small intestinal mucins of N.b-infected rats and purified by ion-exchange chromatography followed by normal-phase HPLC. Two HCM31-reactive oligosaccharide-alditols were obtained. Analyses using tandem mass spectrometry and NMR spectroscopy showed that these oligosaccharides were core 4 mucin-type oligosaccharides having a common tetrasaccharide sequence, NeuAcα2-3(GalNAcβ1-4)Galβ1-4GlcNAcβ- (Sda blood group antigen). These structures were not found in the small intestinal mucin oligosaccharides from uninfected rats. This epitope specificity of HCM31 was also confirmed using previously established anti-GM2 and anti-Sda antibodies. Taken together, these results strongly suggest that HCM31 specifically recognizes mucin-type oligosaccharides with the Sda tetrasaccharide sequence. Immunohistochemical examination of human gastrointestinal tracts showed that HCM31 site-specifically stained the goblet cells in normal sigmoid colon and normal rectum, but the goblet cells stained with HCM31 were reduced in the corresponding cancer tissues. HCM31 seems to be useful for diagnosis of colonic cancer and for examining the function of secretory-type mucin with Sda antigen.

Tumor necrosis factor receptor 1-dependent depletion of mucus in immature small intestine: a potential role in neonatal necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants. NEC is believed to occur when intestinal bacteria invade the intestinal epithelial layer, causing subsequent inflammation and tissue necrosis. Mucins are produced and secreted by epithelial goblet cells as a key component of the innate immune system and barrier function of the intestinal tract that help protect against bacterial invasion. To better understand the role of mucins in NEC, we quantified the number of mucus-containing small intestinal goblet cells present in infants with NEC and found they had significantly fewer goblet cells and Paneth cells compared with controls. To test whether inflammation has a developmentally dependent effect on intestinal goblet cells, TNF-α was injected into mice at various stages of intestinal development. TNF-α caused a loss of mucus-containing goblet cells only in immature mice and induced Muc2 and Muc3 mRNA upregulation only in mature ileum. Only minimal changes were seen in apoptosis and in expression of markers of goblet cell differentiation. TNF-α increased small intestinal mucus secretion and goblet cell hypersensitivity to prostaglandin E2 (PGE(2)), a known mucus secretagogue produced by macrophages. These TNF-α-induced changes in mucus mRNA levels required TNF receptor 2 (TNFR2), whereas TNF-α-induced loss of mucus-positive goblet cells required TNFR1. Our findings of developmentally dependent TNF-α-induced alterations on intestinal mucus may help explain why NEC is predominantly found in premature infants, and TNF-α-induced alterations of the intestinal innate immune system and barrier functions may play a role in the pathogenesis of NEC itself.

Role of Intestinal Bacteria in Gliadin-Induced Changes in Intestinal Mucosa: Study in Germ-Free Rats

Background and AimsCeliac disease (CD) is a chronic inflammatory disorder of the small intestine that is induced by dietary wheat gluten proteins (gliadins) in genetically predisposed individuals. The overgrowth of potentially pathogenic bacteria and infections has been suggested to contribute to CD pathogenesis. We aimed to study the effects of gliadin and various intestinal bacterial strains on mucosal barrier integrity, gliadin translocation, and cytokine production.Methodology/Principal FindingsChanges in gut mucosa were assessed in the intestinal loops of inbred Wistar-AVN rats that were reared under germ-free conditions in the presence of various intestinal bacteria (enterobacteria and bifidobacteria isolated from CD patients and healthy children, respectively) and CD-triggering agents (gliadin and IFN-γ) by histology, scanning electron microscopy, immunofluorescence, and a rat cytokine antibody array. Adhesion of the bacterial strains to the IEC-6 rat cell line was evaluated in vitro.Gliadin fragments alone or together with the proinflammatory cytokine interferon (IFN)-γ significantly decreased the number of goblet cells in the small intestine; this effect was more pronounced in the presence of Escherichia coli CBL2 and Shigella CBD8. Shigella CBD8 and IFN-γ induced the highest mucin secretion and greatest impairment in tight junctions and, consequently, translocation of gliadin fragments into the lamina propria. Shigella CBD8 and E. coli CBL2 strongly adhered to IEC-6 epithelial cells. The number of goblet cells in small intestine increased by the simultaneous incubation of Bifidobacterium bifidum IATA-ES2 with gliadin, IFN-γ and enterobacteria. B. bifidum IATA-ES2 also enhanced the production of chemotactic factors and inhibitors of metalloproteinases, which can contribute to gut mucosal protection.ConclusionsOur results suggest that the composition of the intestinal microbiota affects the permeability of the intestinal mucosa and, consequently, could be involved in the early stages of CD pathogenesis.

Nippostrongylus brasiliensis: Increase of sialomucins reacting with anti-mucin monoclonal antibody HCM31 in rat small intestinal mucosa with primary infection and reinfection

Infections with the parasitic helminth, Nippostrongylus brasiliensis, cause changes in rat small intestinal goblet cell mucin, particularly in the peripheral sugar residues of oligosaccharide. These changes may correlate with expulsion. In this study, we examined changes in mucin oligosaccharides caused by primary infection and reinfection with N. brasiliensis, using two monoclonal antibodies, HCM31 and PGM34, that react with sialomucin and sulfomucin, respectively. Enzyme-linked immunosorbent assay of jejunal mucins showed that the relative reactivity of mucins with HCM31, but not PGM34, increased up to 16 days after primary infection and 6 days after reinfection, the times when the worms were expelled from the rats. Immunohistochemical studies confirmed that goblet cells stained with HCM31 greatly increased at the time of worm expulsion. These results indicate that the marked increase observed in HCM31-reactive sialomucins may be related to expulsion of the worms.

Lkb1 Deficiency Alters Goblet and Paneth Cell Differentiation in the Small Intestine

The Lkb1 tumour suppressor is a multitasking kinase participating in a range of physiological processes. We have determined the impact of Lkb1 deficiency on intestinal homeostasis, particularly focussing on secretory cell differentiation and development since we observe strong expression of Lkb1 in normal small intestine Paneth and goblet cells. We crossed mice bearing an Lkb1 allele flanked with LoxP sites with those carrying a Cyp1a1-specific inducible Cre recombinase. Lkb1 was efficiently deleted from the epithelial cells of the mouse intestine after intraperitoneal injection of the inducing agent β-naphthoflavone. Bi-allelic loss of Lkb1 led to the perturbed development of Paneth and goblet cell lineages. These changes were characterised by the lack of Delta ligand expression in Lkb1-deficient secretory cells and a significant increase in the levels of the downstream Notch signalling effector Hes5 but not Hes1. Our data show that Lkb1 is required for the normal differentiation of secretory cell lineages within the intestine, and that Lkb1 deficiency modulates Notch signalling modulation in post-mitotic cells.

Bacterial Modulation of Small Intestinal Goblet Cells and Mucin Composition During Early Posthatch Development of Poultry

Mucins possess potential binding sites for both commensal and pathogenic organisms and may perform a defensive role during establishment of the intestinal barrier. To observe the effects of bacteria on intestinal goblet cell mucin production during posthatch development, differences in the small intestine of conventionally reared (CR) and low bacterial load (LBL) broiler chicks were examined. Jejunal and ileal goblet cells were stained with either periodic acid-Schiff stain or high iron diaminealcian blue pH 2.5 to discriminate among neutral, sulfated, and sialylated acidic mucins. Total goblet cell numbers and morphology of goblet cells containing neutral and acidic mucins did not differ significantly between CR and LBL birds. However, significant differences in acidic mucin composition from primarily sulfated to an increase in sialylated sugars at d 4 posthatch were observed in CR chicks, with greater numbers of jejunal and ileal goblet cells displaying this mucin type (CR, 0.5 +/- 0.1 x 10(3) cells/mm(2); LBL, 0.04 +/- 0.02 x10(3) cells/mm(2)). This change in mucin profile in response to bacterial colonization suggests a potential role as a protective mechanism against pathogenic invasion of the intestinal mucosa during early development.

Consumption of aqueous extract of raw &lt;i&gt;Aloe Vera&lt;/i&gt; leaves: histopathological and biochemical studies in rat and tilapia

Forty-five juvenile tilapia and 30 weanling albino rats exposed to water containing 50, 100 and 150ppm of aqueous extract of Aloe Vera leaves for 96 hours and 28 days, respectively were used for this study. Fifteen tilapia and 10 rats exposed to clean water (0 ppm A. vera) served as controls. Clinical signs, mortality, gross and histologic organ pathology in the tilapia; weekly haematology, plasma biochemical parameters and organ pathology were monitored in the rats. Fish cultured in water containing A. vera exhibited erratic swimming patterns, rapid opercular movements, skin depigmentation and died within 24-96 hours. Gross and histologic tissue lesions in the test fish include skin depigmentation, pale and shriveled gills, dull, opaque and sunken eyes, stunting and clubbing of gill filaments, vacuolar degeneration and necrosis of gill epithelial cells, hyaline degeneration and necrosis of myofibrils, calcification of vasa vasori, hepatocellular vacuolar degeneration and necrosis. Haematologic and plasma biochemical changes in test rats include moderate to severe normocytic normochromic anaemia, hypoproteinaemia, increased AST levels, and decreased cholesterol and triglyceride levels. Gross and histologic tissue lesions include mild to moderate pulmonary congestion, flabbiness of the heart, hepatomegaly, mottling of kidneys, vacuolar degeneration and necrosis of hepatocytes, Kupffer cell hyperplasia, periportal fibrosis, glomerular and tubular degeneration and necrosis, matting and clubbing of small intestinal villi, catarrhal enteritis and goblet cell hyperplasia. The severity of these changes increased with increasing concentrations of A. vera. No mortality, gross or histologic changes were observed in both control fish and rats. Results from this study show that consumption of water containing extracts of raw A. vera is very toxic to fish and rats. The serious health implication for human consumption of raw A. vera is discussed. Keywords: aloe vera, tilapia, rats, alternate medicine, human health implications African Journal of Biomedical Research Vol. 8(3) 2005: 169-178

Keratin 20 Serine 13 Phosphorylation Is a Stress and Intestinal Goblet Cell Marker

Keratin polypeptide 20 (K20) is an intermediate filament protein with preferential expression in epithelia of the stomach, intestine, uterus, and bladder and in Merkel cells of the skin. K20 expression is used as a marker to distinguish metastatic tumor origin, but nothing is known regarding its regulation and function. We studied K20 phosphorylation as a first step toward understanding its physiologic role. K20 phosphorylation occurs preferentially on serine, with a high stoichiometry as compared with keratin polypeptides 18 and 19. Mass spectrometry analysis predicted that either K20 Ser(13) or Ser(14) was a likely phosphorylation site, and Ser(13) was confirmed as the phospho-moiety using mutation and transfection analysis and generation of an anti-K20-phospho-Ser(13) antibody. K20 Ser(13) phosphorylation increases after protein kinase C activation, and Ser(13)-to-Ala mutation interferes with keratin filament reorganization in transfected cells. In physiological contexts, K20 degradation and associated Ser(13) hyperphosphorylation occur during apoptosis, and chemically induced mouse colitis also promotes Ser(13) phosphorylation. Among mouse small intestinal enterocytes, K20 Ser(13) is preferentially phosphorylated in goblet cells and undergoes dramatic hyperphosphorylation after starvation and mucin secretion. Therefore, K20 Ser(13) is a highly dynamic protein kinase C-related phosphorylation site that is induced during apoptosis and tissue injury. K20 Ser(13) phosphorylation also serves as a unique marker of small intestinal goblet cells.

Cellular differentiation status of epithelial polyps of the colorectum: the gastric foveolar cell-type in hyperplastic polyps.

The 'metaplastic' polyp of the colorectum, a synonym for the hyperplastic polyp, was named based only on features of the crypt epithelium. It is considered non-neoplastic, but the precise cellular differentiation status remains to be proven. Forty-eight hyperplastic polyps, 12 serrated adenomas, 45 tubular adenomas and five juvenile polyps were studied for their phenotypic expression using gastric (foveolar or pyloric gland cell), small intestinal (goblet cell), and colonic (goblet cell) cellular markers by immunohistochemical and mucin histochemical techniques. Gastric foveolar cell-type differentiation was significantly expressed in hyperplastic polyps, while colonic differentiation was also consistently preserved. Neither gastric pyloric-type nor small intestinal differentiation was observed. The same cell differentiation status as hyperplastic polyps was observed in serrated adenomas but not in tubular adenomas or juvenile polyps. A large proportion of hyperplastic polyps are composed of hybrid epithelium, with bidirectional differentiation to both gastric foveolar and colonic epithelial cells in the same crypt. Therefore hyperplastic polyps might be interpreted as the outcome of abnormal cell differentiation of stem cells. The same phenotypic expression suggests that hyperplastic polyps and serrated adenomas share the same cell lineage.

Pre- and posthatch development of goblet cells in the broiler small intestine: effect of delayed access to feed

Mucin glycoproteins play a key role in the regular function of the epithelium of the gastrointestinal tract, and in this study, the ontogenesis and development of mucin producing cells was examined in the broiler. Mucin-producing cells were observed in the small intestine from 3 d before hatch, and at this time contained only acidic mucin. After hatch and until Day 7 posthatch, the proximal, middle, and distal segments of the small intestine contained similar proportions of goblet cells producing acidic and neutral mucins. A gradient of goblet cell density was observed increasing along the duodenal to ileal axis. Delayed access to feed for 48 h posthatch resulted in an increase in intestinal intracellular mucins, which might have been due to impaired mucin secretion or enhanced mucin production. Changes in mucin dynamics could affect absorptive and protective functions of the small intestine.

Rat small intestinal goblet cell kinetics in the process of restitution of surface epithelium subjected to ischemia-reperfusion injury.

Repair of superficial damage to gastrointestinal mucosa occurs by a process called restitution. Goblet cells reside throughout the length of the intestine and are responsible for the production of mucus. However, a kinetic analysis of goblet cell dynamics of small intestine in restitution has hitherto not been reported. The aim of the present study was to investigate the role of goblet cells in the process of restitution of rat small intestine subjected to ischemia and ischemia-reperfusion injury, and therefore intestinal epithelium from rats subjected to both ischemia and ischemia-reperfusion was studied. Detachment of enterocytes was observed after 5-min of reperfusion. After 20-30 minutes of reperfusion, the denuded villous tips were covered with goblet cells. Within 75 min of reperfusion the epithelium restitution was complete. On the other hand, restitution was not observed in ischemia group. These data suggest that goblet cells may play an important role in restitution after ischemia-reperfusion injury.