Background
Crohn’s disease (CD) is a chronic and destructive bowel disease; continued disease activity can lead to penetrating complications. With the recent advent of effective medications, the ...importance of using a treat-to-target approach to guide therapy is becoming important.
Methods
In this review, we reviewed the previous evidence for evaluating CD lesions.
Results
We describe ileocolonoscopy’s role in assessing disease activity, as well as recent progress in modalities, such as balloon-assisted endoscopy, capsule endoscopy, magnetic resonance enterography, computed tomography enterography, and ultrasonography. Advances in modalities have changed CD assessment, with small-bowel involvement becoming more important.
Conclusions
Proper optimization is necessary in clinical practice.
Continuous renewal of the intestinal epithelium requires coordinated regulation to maintain the balance between proliferation and differentiation of the epithelial stem cells and immature progenitor ...cells. Canonical Wnt signaling has long been regarded as the signaling pathway playing a central role in this epithelial cell fate determination; however, recent studies have shown that Notch signaling is also indispensable for this process. Here, we review the current concepts of how the Wnt and Notch pathways control intestinal epithelial cell fate decisions, particularly focusing on their crosstalk at both tissue and cellular levels. As several features are shared between stem cell renewal and cancer cell renewal, comprehensive understanding of how the Wnt and Notch signaling pathways cooperate and integrate in the gut epithelium has significant implications for the development of novel therapeutic modalities for intestinal neoplasia.
In Japan and other Asian countries, increased fat uptake induced by a westernized diet is thought to be associated with an increased incidence of inflammatory bowel disease, colorectal cancer and ...food allergies; however, the mechanism for this remains unclear. High-fat diet (HFD)-fed mice are common animal models used to examine the effect of fat intake in vivo. HFDs are reported to exacerbate DSS-induced colitis and intestinal tumorigenesis, but the effect of HFDs on the intestines before disease induction is often overlooked. We found that the intestinal and gut-associated lymphoid tissue (GALT) morphology of HFD-fed mice differed from that of standard diet (SD)-fed mice. To clarify the mechanism by which fat intake increases intestinal diseases, we analyzed the morphological and immunological aspects of the intestines of HFD-fed mice as well as the molecular mechanisms and physiology.
Feeding an HFD for 3 weeks induced atrophy of the small intestine, colon and GALT and reduced the number of small intestinal intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs). Feeding an HFD for only one day reduced the number of small intestinal (SI)-IELs and SI-LPLs. The effect of feeding a 3-week HFD continued for 2 weeks after returning to the SD. The effect of the HFD on the intestinal immune system was independent of the gut microbes. We hypothesized that the cytotoxicity of the abundant HFD-derived free fatty acids in the intestinal lumen impairs the intestinal immune system. Both saturated and unsaturated free fatty acids were toxic to intestinal T-cells in vitro. Orally administering free fatty acids reduced the number of SI-IELs and LPLs. Using a lipase inhibitor to reduce the luminal free fatty acids attenuated the HFD-induced changes in the intestinal immune system, while using a statin to reduce the serum free fatty acids did not. Thus, HFD-induced free fatty acids damaged the intestines; this effect was termed “intestinal lipotoxicity”. Because sustained reduction of SI-LPLs after HFD feeding exacerbated indomethacin-induced small intestinal damage, lipotoxicity to the human intestines incurred by consuming a westernized diet in Japan may increase intestinal diseases such as IBD, colorectal cancer or food allergies.
•Feeding a high-fat diet (HFD) induced atrophy of the intestines.•Feeding an HFD reduced the number of small intestinal T-cells, too.•We defined these phenotypes as termed intestinal lipotoxicity.•Intestinal lipotoxicity was caused by cytotoxicity from HFD-derived free fatty acids.•Intestinal lipotoxicity exacerbated indomethacin-induced small intestinal damage.
Background
l
-amino acids are the predominant forms of organic molecules on the planet, but recent studies have revealed that various foods contain
d
-amino acids, the enantiomers of
l
-amino acids. ...Though diet plays important roles in both the development and progression of inflammatory bowel disease (IBD), to our best knowledge, there has been no report on any potential interactions between
d
-amino acids and IBD. In this report, we aim to assess the effects of
d
-serine in a murine model of IBD.
Materials and methods
To induce chronic colitis, naïve CD4 T cells (CD4
+
CD62
+
CD44
low
) from wild-type mice were adoptively transferred into
Rag2
−/−
mice, after or before the mice were orally administered with
d
-serine. In vitro proliferation assays were performed to assess naïve CD4 T cell activation under the Th-skewing conditions in the presence of
d
-serine.
Results
Mice treated with
d
-serine prior to the induction of colitis exhibited a reduction in T-cell infiltration into the lamina propria and colonic inflammation that were not seen in mice fed with water alone or
l
-serine. Moreover,
d
-serine suppressed the progression of chronic colitis when administered after the disease induction. Under in vitro conditions,
d
-serine suppressed the proliferation of activated CD4 T cells and limited their ability to differentiate to Th1 and Th17 cells.
Conclusion
Our results suggest that
d
-serine not only can prevent, but also has efficacious effects as a treatment for IBD.
Background
Intestinal stem cells (ISCs) play indispensable roles in the maintenance of homeostasis, and also in the regeneration of the damaged intestinal epithelia. However, whether the inflammatory ...environment of Crohn’s disease (CD) affects properties of resident small intestinal stem cells remain uncertain.
Methods
CD patient-derived small intestinal organoids were established from enteroscopic biopsy specimens taken from active lesions (aCD-SIO), or from mucosa under remission (rCD-SIO). Expression of ISC-marker genes in those organoids was examined by immunohistochemistry, and also by microfluid-based single-cell multiplex gene expression analysis. The ISC-specific function of organoid cells was evaluated using a single-cell organoid reformation assay.
Results
ISC-marker genes, OLFM4 and SLC12A2, were expressed by an increased number of small intestinal epithelial cells in the active lesion of CD. aCD-SIOs, rCD-SIOs or those of non-IBD controls (NI-SIOs) were successfully established from 9 patients. Immunohistochemistry showed a comparable level of OLFM4 and SLC12A2 expression in all organoids. Single-cell gene expression data of 12 ISC-markers were acquired from a total of 1215 cells. t-distributed stochastic neighbor embedding analysis identified clusters of candidate ISCs, and also revealed a distinct expression pattern of SMOC2 and LGR5 in ISC-cluster classified cells derived from aCD-SIOs. Single-cell organoid reformation assays showed significantly higher reformation efficiency by the cells of the aCD-SIOs compared with that of cells from NI-SIOs.
Conclusions
aCD-SIOs harbor ISCs with modified marker expression profiles, and also with high organoid reformation ability. Results suggest modification of small intestinal stem cell properties by unidentified factors in the inflammatory environment of CD.
The definition of functional gastrointestinal disorders (FGID) used to be disorders that do not manifest into organic abnormalities. However, it was pointed out that chronic GI dysfunctions can ...develop following bacterial infections such as acute gastroenteritis and viral infections, and some organic changes in the epithelial cell structure, immunocompetent cells, and inflammatory cytokines were revealed. Recent advancements in analytical methods helped discover changes in the intestinal microbiota of patients with FGID. Correlations between the effects on the enteric environment and clinical conditions and symptoms of FGID are drawing increasing attention.
Background
Ulcerative colitis (UC) is a chronic inflammatory disease of the colon with an intractable, recurrent course. The goal of UC therapy is to target mucosal healing because immune-suppressive ...therapy for UC frequently results in relapse. However, few drugs directly target mucosal healing. We, therefore, aim to evaluate the therapeutic effect of an investigational drug on intestinal epithelial cells in an in vitro UC model using human colonic organoids.
Methods
Colonic organoids were isolated from human colon and cultured. A mixture of cytokines and bacterial components were used to mimic UC in humans. The effect of the investigational drug on colonic organoid was evaluated by microarray analysis and 3D immunofluorescence. The enrichment of stem cells was assessed with a colony formation assay.
Results
Inflammatory stimulation resulted in a significant induction of inflammatory-related genes in colonic organoids whereas cell differentiation was suppressed. Treatment with the investigational drug KAG-308 showed reciprocal dynamics of gene expression to inflammatory stimulation, which resulted in not only the suppression of immune response but also the promotion of cellular differentiation towards secretory lineages. Moreover, SPDEF and Reg4 were identified as novel targets for the enrichment of intestinal epithelial stem cells and mucosal healing.
Conclusions
The establishment of in vitro UC model using human colonic organoid could reveal the effects and targets of investigational drugs in intestinal epithelial cells under inflammation conditions. Further maturation of this system might be more efficient to predict the effect on UC, as compared with the use of animal model, for the development of new drugs.
Radiation therapy is a lower invasive local treatment than surgery and is selected as a primary treatment for solid tumors. However, when some cancer cells obtain radiotherapy tolerance, cytotoxicity ...of radiotherapy for cancer cells is attenuated. Photodynamic therapy (PDT) is a non-invasive cancer therapy combined with photosensitizers and laser irradiation with an appropriate wavelength. PDT is carried out for recurrent esophageal cancer patients after radiation chemotherapy and is an effective treatment for radiation-resistant tumors. However, it is not clear why PDT is effective against radioresistant cancers. In this study, we attempted to clear this mechanism using X-ray resistant cancer cells. X-ray resistant cells produce high amounts of mitochondria-derived ROS, which enhanced nuclear translocation of NF-κB, resulting in increased NO production. Moreover, the expression of PEPT1 that imports 5-aminolevulinic acid, the precursor of photosensitizers, was upregulated in X-ray resistant cancer cells. This was accompanied by an increase in intracellular 5-aminolevulinic acid-derived porphyrin accumulation, resulting in enhancement of PDT-induced cytotoxicity. Therefore, effective accumulation of photosensitizers induced by ROS and NO may achieve PDT after radiation therapy and PDT could be a promising treatment for radioresistant cancer cells.
Background
The organoids therapy for ulcerative colitis (UC) is under development. It is important to dissect how the engrafted epithelium can provide benefits for overcoming the vulnerability to ...inflammation. We mainly focused on the deliverability of sulfomucin, which is reported to play an important role in epithelial function.
Methods
We analyzed each segment of colon epithelium to determine differences in sulfomucin production in both mice and human. Subsequently, we transplanted organoids established from sulfomucin-enriched region into the injured recipient epithelium following dextran sulfate sodium-induced colitis and analyzed the engrafted epithelium in mouse model.
Results
In human normal colon, sulfomucin production was increased in proximal colon, whereas it was decreased in the inflammatory region of UC. In murine colon epithelium, increased sulfomucin production was found in cecum compared to distal small intestine and proximal colon. RNA sequencing analysis revealed that several key genes associated with sulfomucin production such as
Papss2
and
Slc26a1
were enriched in isolated murine cecum crypts. Then we established murine cecum organoids and transplanted them into the injured epithelium of distal colon. Although the expression of sulfomucin was temporally decreased in cecum organoids, its secretion was restored again in the engrafted patches after transplantation. Finally, we verified a part of mechanisms controlling sulfomucin production in human samples.
Conclusion
This study illustrated the deliverability of sulfomucin in the disease-relevant grafting model to design sulfomucin-producing epithelial units in severely injured distal colon. The current study is the basis for the better promotion of organoids transplantation therapy for refractory UC.
Ubiquitination is a crucial post-translational modification; however, the functions of ubiquitin-coding genes remain unclear. UBA52 encodes a fusion protein comprising ubiquitin at the N-terminus and ...ribosomal protein L40 (RPL40) at the C-terminus. Here we showed that Uba52-deficient mice die during embryogenesis. UBA52-deficient cells exhibited normal levels of total ubiquitin. However, UBA52-deficient cells displayed decreased protein synthesis and cell-cycle arrest. The overexpression of UBA52 ameliorated the cell-cycle arrest caused by UBA52 deficiency. Surprisingly, RPL40 expression itself is insufficient to regulate cyclin D expression. The cleavage of RPL40 from UBA52 was required for maintaining protein synthesis. Furthermore, we found that RPL40 formed a ribosomal complex with ubiquitin cleaved from UBA52. UBA52 supplies RPL40 and ubiquitin simultaneously to the ribosome. Our study demonstrated that the ubiquitin-coding gene UBA52 is not just an ubiquitin supplier to the ubiquitin pool but is also a regulator of the ribosomal protein complex. These findings provide novel insights into the regulation of ubiquitin-dependent translation and embryonic development.
PDF
