Goblet Cell Expansion Research Articles

Epithelial-stromal interaction via Notch signaling is essential for the full maturation of gut-associated lymphoid tissues.

Intrinsic Notch signaling in intestinal epithelial cells restricts secretory cell differentiation. In gut-associated lymphoid tissue (GALT), stromal cells located beneath the follicle-associated epithelium (FAE) abundantly express the Notch ligand delta-like 1 (Dll1). Here, we show that mice lacking Rbpj-a gene encoding a transcription factor implicated in Notch signaling-in intestinal epithelial cells have defective GALT maturation. This defect can be attributed to the expansion of goblet cells, which leads to the down-regulation of CCL20 in FAE. These data demonstrate that epithelial Notch signaling maintained by stromal cells contributes to the full maturation of GALT by restricting secretory cell differentiation in FAE.

TGFβ signaling inhibits goblet cell differentiation via SPDEF in conjunctival epithelium.

The ocular surface epithelia, including the stratified but non-keratinized corneal, limbal and conjunctival epithelium, in concert with the epidermal keratinized eyelid epithelium, function together to maintain eye health and vision. Abnormalities in cellular proliferation or differentiation in any of these surface epithelia are central in the pathogenesis of many ocular surface disorders. Goblet cells are important secretory cell components of various epithelia, including the conjunctiva; however, mechanisms that regulate goblet cell differentiation in the conjunctiva are not well understood. Herein, we report that conditional deletion of transforming growth factor β receptor II (Tgfbr2) in keratin 14-positive stratified epithelia causes ocular surface epithelial hyperplasia and conjunctival goblet cell expansion that invaginates into the subconjunctival stroma in the mouse eye. We found that, in the absence of an external phenotype, the ocular surface epithelium develops properly, but young mice displayed conjunctival goblet cell expansion, demonstrating that TGFβ signaling is required for normal restriction of goblet cells within the conjunctiva. We observed increased expression of SAM-pointed domain containing ETS transcription factor (SPDEF) in stratified conjunctival epithelial cells in Tgfbr2 cKO mice, suggesting that TGFβ restricted goblet cell differentiation directly by repressing Spdef transcription. Gain of function of Spdef in keratin 14-positive epithelia resulted in the ectopic formation of goblet cells in the eyelid and peripheral cornea in adult mice. We found that Smad3 bound two distinct sites on the Spdef promoter and that treatment of keratin 14-positive cells with TGFβ inhibited SPDEF activation, thereby identifying a novel mechanistic role for TGFβ in regulating goblet cell differentiation.

Type 3 Muscarinic Receptors (M3R) Contribute to Expulsion of Nippostrongylus brasiliensis Through Induction of Th2 Cytokines

Introduction: Lower rates of helminth infection in persons from developed countries are associated with a higher prevalence of autoimmune diseases including IBD (Weinstock & Elliott, 2009). In mice, infection with the enteric nematode Nippostrongylus brasiliensis (Nb) induces a Th2 cytokine response in small intestine (SI) and characteristic STAT6/IL-13 dependent changes in gut function including increased permeability, smooth muscle hypercontractility, decreased fluid absorption and secretion, and goblet cell expansion. We showed previously that M3R promotes clearance of the enteric bacterium Citrobacter rodentium (Cr). The contribution of M3R to expulsion of enteric nematodes is unclear. Aim: To investigate the hypothesis that M3R affects clearance of Nb. Methods: WT and M3R-/- mice were infected with 500 third-stage Nb larvae. Worm and fecal egg counts were performed to assess clearance. Expression of the Th2 cytokines IL-4 and IL-13, the Th1/Th17 cytokines IFN-γ, TNF-α, and IL-17, and the T-cell marker CD3 was assessed by real-time PCR. Epithelial permeability, secretion and absorption in response to acetylcholine and glucose, smooth muscle tension, and goblet cell expansion were determined. Results: Worm and fecal egg counts were significantly higher in Nb-infected M3R-/- mice. Expression of IFN-γ was modestly, but significantly, upregulated in Nb-infected M3R-/- SI. TNF-α and IL-17 expression were similar. Expression of IL-4 and IL-13 was upregulated significantly in Nb-infected WT SI, but abrogated in Nb-infected M3R-/- SI (Table). These changes were not due to altered T cell recruitment to M3R-/- SI as expression of CD3 was similar in Nb-infected WT and M3R-/- SI. Characteristic alterations in gut function occurred in Nb-infected WT mice, but not Nb-infected M3R-/- mice. Summary: Clearance of Nb is delayed from M3R-/- mice and is associated with absent upregulation of Th2 cytokines and a modest upregulation of IFN-γ. The impaired Th2 response in M3R-/- mice is associated with absent downstream STAT6/IL-13 dependent alterations in gut physiology that promote worm expulsion. Conclusion: We previously reported that M3R-deficiency is associated with delayed clearance of Cr, but an intact Th1/Th17 cytokine response. Our findings here support a role for M3R in the induction of Th2 cytokines in response to enteric nematode infection and suggest a differential role for M3R in the regulation of and response to pathogens that trigger Th1/Th17 (Cr) versus Th2 (Nb) immune responses.Table 1: Expression of IL-4 and IL-13 in uninfected and Nb-infected WT and M3R-/- small intestine

Differential Immune Responses and Pulmonary Pathophysiology Are Induced by Two Different Strains of Respiratory Syncytial Virus

In this study we performed comparisons of pulmonary responses between two different respiratory syncytial virus (RSV) antigenic subgroup A strains, A2 and Line 19. Line 19 strain induced significant dose-responsive airway hyperreactivity (AHR) in BALB/c mice at days 6 and 9 after infection, whereas the A2 strain induced no AHR at any dose. Histological examination indicated that A2 induced no goblet cell hyper/metaplasia, whereas the Line 19 induced goblet cell expansion and significant increases in gob5 and MUC5AC mRNA and protein levels in vivo. When examining cytokine responses, A2 strain induced significant interleukin (IL)-10 expression, whereas Line 19 strain induced significant IL-13 expression. When IL-13-/- mice were infected with Line 19 RSV, the AHR responses were abrogated along with gob5 gene expression. There was little difference in viral titer throughout the infection between the line 19- and A2-infected mice. However, the A2 strain grew to significantly higher titers than the Line 19 strain in HEp-2 cells in vitro. Thus, RSV Line 19-induced airway dysfunction does not correlate with viral load in vivo. These data demonstrate that different RSV strains of the same antigenic subgroup can elicit differential immune responses that impact the phenotypic expression of RSV-induced illness.

Acidomucin goblet cell expansion induced by parenteral nutrition in the small intestine of piglets.

Total parenteral nutrition (TPN) impairs small intestine development and is associated with barrier failure, inflammation, and acidomucin goblet cell expansion in neonatal piglets. We examined the relationship between intestinal goblet cell expansion and molecular and cellular indices of inflammation in neonatal piglets receiving TPN, 80% parenteral + 20% enteral nutrition (PEN), or 100% enteral nutrition (control) for 3 or 7 days. Epithelial permeability, T cell numbers, TNF-alpha and IFN-gamma mRNA expression, and epithelial proliferation and apoptosis were compared with goblet cell numbers over time. Epithelial permeability was similar to control in the TPN and PEN jejunum at day 3 but increased in the TPN jejunum by day 7. By day 3, intestinal T cell numbers were increased in TPN but not in PEN piglets. However, goblet cell expansion was established by day 3 in both the TPN and PEN ileum. Neither TNF-alpha nor IFN-gamma mRNA expression in the TPN and PEN ileum correlated with goblet cell expansion. Thus goblet cell expansion occurred independently of overt inflammation but in association with parenteral feeding. These data support the hypothesis that goblet cell expansion represents an initial defense triggered by reduced epithelial renewal to prevent intestinal barrier failure.