| 1. |
- Birchenough, George M. H., et al.
(författare)
-
A sentinel goblet cell guards the colonic crypt by triggering Nlrp6-dependent Muc2 secretion
- 2016
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 352:6293, s. 1535-1542
-
Tidskriftsartikel (refereegranskat)abstract
- Innate immune signaling pathways contribute to the protection of host tissue when bacterially challenged. Colonic goblet cells are responsible for generating the two mucus layers that physically separate the luminalmicrobiota from the host epithelium. Analysis of colonic tissues from multiple mouse strains allowed us to identify a "sentinel" goblet cell (senGC) localized to the colonic crypt entrance. This cell nonspecifically endocytoses and reacts to the TLR2/1, TLR4, and TLR5 ligands by activating the Nlrp6 inflammasome downstream of TLR-and MyD88-dependent Nox/Duox reactive oxygen species synthesis. This triggers calcium ion-dependent compound exocytosis ofMuc2 mucin fromthe senGC and generates an intercellular gap junction signal; in turn, this signal induces Muc2 secretion from adjacent goblet cells in the upper crypt, which expels bacteria. Thus, senGCs guard and protect the colonic crypt from bacterial intruders that have penetrated the inner mucus layer.
|
|
| 2. |
- Nyström, Elisabeth E. L., et al.
(författare)
-
An intercrypt subpopulation of goblet cells is essential for colonic mucus barrier function
- 2021
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 372:6539
-
Tidskriftsartikel (refereegranskat)abstract
- The intestinal mucus layer, an important element of epithelial protection, is produced by goblet cells. Intestinal goblet cells are assumed to be a homogeneous cell type. In this study, however, we delineated their specific gene and protein expression profiles and identified several distinct goblet cell populations that form two differentiation trajectories. One distinct subtype, the intercrypt goblet cells (icGCs), located at the colonic luminal surface, produced mucus with properties that differed from the mucus secreted by crypt-residing goblet cells. Mice with defective icGCs had increased sensitivity to chemically induced colitis and manifested spontaneous colitis with age. Furthermore, alterations in mucus and reduced numbers of icGCs were observed in patients with both active and remissive ulcerative colitis, which highlights the importance of icGCs in maintaining functional protection of the epithelium.
|
|
| 3. |
- Nyström, Elisabeth E. L., et al.
(författare)
-
Calcium-activated Chloride Channel Regulator 1 (CLCA1) Controls Mucus Expansion in Colon by Proteolytic Activity
- 2018
-
Ingår i: Ebiomedicine. - : Elsevier BV. - 2352-3964. ; 33, s. 134-143
-
Tidskriftsartikel (refereegranskat)abstract
- Many epithelial surfaces of the body are covered with protective mucus, and disrupted mucus homeostasis is coupled to diseases such as ulcerative colitis, helminth infection, cystic fibrosis, and chronic obstructive lung disease. However, little is known how a balanced mucus system is maintained. By investigating the involvement of proteases in colonic mucus dynamics we identified metalloprotease activity to be a key contributor to mucus expansion. The effect was mediated by calcium-activated chloride channel regulator 1 (CLCA1) as application of recombinant CLCA1 on intestinal mucus in freshly dissected tissue resulted in increased mucus thickness independently of ion and mucus secretion, but dependent on its metallohydrolase activity. Further, CLCA1 modulated mucus dynamics in both human and mouse, and knock-out of CLCA1 in mice was compensated for by cysteine proteases. Our results suggest that CLCA1 is involved in intestinal mucus homeostasis by facilitating processing and removal of mucus to prevent stagnation. In light of our findings, we suggest future studies to investigate if upregulation of CLCA1 in diseases associated with mucus accumulation could facilitate removal of mucus in an attempt to maintain homeostasis. (C) 2018 The Authors. Published by Elsevier B.V.
|
|
| 4. |
- Nyström, Elisabeth E. L., et al.
(författare)
-
Calcium-activated chloride channel regulator 1 (CLCA1) forms non-covalent oligomers in colonic mucus and has mucin 2-processing properties
- 2019
-
Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 294:45, s. 17075-17089
-
Tidskriftsartikel (refereegranskat)abstract
- Calcium-activated chloride channel regulator 1 (CLCA1) is one of the major nonmucin proteins found in intestinal mucus. It is part of a larger family of CLCA proteins that share highly conserved features and domain architectures. The CLCA domain arrangement is similar to proteins belonging to the ADAM (a disintegrin and metalloproteinase) family, known to process extracellular matrix proteins. Therefore, CLCA1 is an interesting candidate in the search for proteases that process intestinal mucus. Here, we investigated CLCA1's biochemical properties both in vitro and in mucus from mouse and human colon biopsy samples. Using immunoblotting with CLCA1-specific antibodies and recombinant proteins, we observed that the CLCA1 C-terminal self-cleavage product forms a disulfide-linked dimer that noncovalently interacts with the N-terminal part of CLCA1, which further interacts to form oligomers. We also characterized a second, more catalytically active, N-terminal product of CLCA1, encompassing the catalytic domain together with its von Willebrand domain type A (VWA). This fragment was unstable but could be identified in freshly prepared mucus. Furthermore, we found that CLCA1 can cleave the N-terminal part of the mucus structural component MUC2. We propose that CLCA1 regulates the structural arrangement of the mucus and thereby takes part in the regulation of mucus processing.
|
|
| 5. |
- Pelaseyed, Thaher, 1979, et al.
(författare)
-
The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system
- 2014
-
Ingår i: Immunological Reviews. - : Wiley. - 0105-2896 .- 1600-065X. ; 260:1, s. 8-20
-
Forskningsöversikt (refereegranskat)abstract
- The gastrointestinal tract is covered by mucus that has different properties in the stomach, small intestine, and colon. The large highly glycosylated gel-forming mucins MUC2 and MUC5AC are the major components of the mucus in the intestine and stomach, respectively. In the small intestine, mucus limits the number of bacteria that can reach the epithelium and the Peyer's patches. In the large intestine, the inner mucus layer separates the commensal bacteria from the host epithelium. The outer colonic mucus layer is the natural habitat for the commensal bacteria. The intestinal goblet cells secrete not only the MUC2 mucin but also a number of typical mucus components: CLCA1, FCGBP, AGR2, ZG16, and TFF3. The goblet cells have recently been shown to have a novel gate-keeping role for the presentation of oral antigens to the immune system. Goblet cells deliver small intestinal luminal material to the lamina propria dendritic cells of the tolerogenic CD103+ type. In addition to the gel-forming mucins, the transmembrane mucins MUC3, MUC12, and MUC17 form the enterocyte glycocalyx that can reach about a micrometer out from the brush border. The MUC17 mucin can shuttle from a surface to an intracellular vesicle localization, suggesting that enterocytes might control and report epithelial microbial challenge. There is communication not only from the epithelial cells to the immune system but also in the opposite direction. One example of this is IL10 that can affect and improve the properties of the inner colonic mucus layer. The mucus and epithelial cells of the gastrointestinal tract are the primary gate keepers and controllers of bacterial interactions with the host immune system, but our understanding of this relationship is still in its infancy.
|
|
| 6. |
- Sharpen, Jack D. A., et al.
(författare)
-
Transglutaminase 3 crosslinks the secreted gel-forming mucus component Mucin-2 and stabilizes the colonic mucus layer
- 2022
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- The colonic mucus layer is organized as a two-layered system providing a physical barrier against pathogens and simultaneously harboring the commensal flora. The factorscontributing to the organization of this gel network are not well understood. In this study, the impact of transglutaminase activity on this architecture was analyzed. Here, we show that transglutaminase TGM3 is the major transglutaminase-isoform expressed and synthesized in the colon. Furthermore, intrinsic extracellular transglutaminase activity in the secreted mucus was demonstrated in vitro and ex vivo. Absence of this acyl-transferase activity resulted in faster degradation of the major mucus component the MUC2 mucin and changed the biochemical properties of mucus. Finally, TGM3-deficient mice showed an early increased susceptibility to Dextran Sodium Sulfate-induced colitis. Here, we report that natural isopeptide cross-linking by TGM3 is important for mucus homeostasis and protection of the colon from inflammation, reducing the risk of colitis. © 2022, The Author(s).
|
|
| 7. |
- Vega, Génesis, et al.
(författare)
-
Normal calcium-activated anion secretion in a mouse selectively lacking TMEM16A in intestinal epithelium
- 2019
-
Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Calcium-activated anion secretion is expected to ameliorate cystic fibrosis, a genetic disease that carries an anion secretory defect in exocrine tissues. Human patients and animal models of the disease that present a mild intestinal phenotype have been postulated to bear a compensatory calcium-activated anion secretion in the intestine. TMEM16A is calcium-activated anion channel whose presence in the intestinal epithelium is contradictory. We aim to test the functional expression of TMEM16A using animal models with Cftr and/or Tmem16a intestinal silencing. Expression of TMEM16A was studied in a wild type and intestinal Tmem16a knockout mice by mRNA-seq, mass-spectrometry, q-PCR, Western blotting and immunolocalization. Calcium-activated anion secretion was recorded in the ileum and proximal colon of these animals including intestinal Cftr knockout and double mutants with dual Tmem16a and Cftr intestinal ablation. Mucus homeostasis was studied by immune-analysis of Mucin-2 (Muc2) and survival curves were recorded. Tmem16a transcript was found in intestine. Nevertheless, protein was barely detected in colon samples. Electrophysiological measurements demonstrated that the intestinal deletion of Tmem16a did not change calcium-activated anion secretion induced by carbachol or ATP in ileum and proximal colon. Muc2 architecture was not altered by Tmem16a silencing as was observed when Cftr was deleted from mouse intestine. Tmem16a silencing neither affected animal survival nor modified the lethality observed in the intestinal Cftr-null mouse. Our results demonstrate that TMEM16A function in the murine intestine is not related to electrogenic calcium-activated anion transport and does not affect mucus homeostasis and survival of animals.
|
|
| 8. |
- Volk, Joana K., et al.
(författare)
-
The Nlrp6 inflammasome is not required for baseline colonic inner mucus layer formation or function
- 2019
-
Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 216:11, s. 2602-2618
-
Tidskriftsartikel (refereegranskat)abstract
- The inner mucus layer (IML) is a critical barrier that protects the colonic epithelium from luminal threats and inflammatory bowel disease. Innate immune signaling is thought to regulate IML formation via goblet cell Nlrp6 inflammasome activity that controls secretion of the mucus structural component Muc2. We report that isolated colonic goblet cells express components of several inflammasomes; however, analysis of IML properties in multiple inflammasome-deficient mice, including littermate-controlled Nlrp6(-/-), detect a functional IML barrier in all strains. Analysis of mice lacking inflammasome substrate cytokines identifies a defective IML in Il18(-/-) mice, but this phenotype is ultimately traced to a microbiota-driven, Il18-independent effect. Analysis of phenotypic transfer between IML-deficient and IML-intact mice finds that the Bacteroidales family S24-7 (Muribaculaceae) and genus Adlercrutzia consistently positively covary with IML barrier function. Together, our results demonstrate that baseline IML formation and function is independent of inflammasome activity and highlights the role of the microbiota in determining IML barrier function.
|
|
