Eosinophilic enteritis accompanied by cytomegalovirus disease: a case report.

BACKGROUND: Eosinophilic enteritis is a chronic inflammatory disorder of the intestinal tract that is characterized by eosinophil infiltration. Cytomegalovirus (CMV), a common virus, has a broad infectivity range. CMV is retained in the host body after infection. Impairment of host immune defences may reactivate the latent CMV, leading to symptoms of overt disease. CASE PRESENTATION: A Japanese female in her 70 s was admitted to a hospital due to diarrhoea and then transferred to our hospital. Laboratory data showed hypoalbuminemia. Computed tomography (CT) revealed oedema of the small intestine. Lower gastrointestinal endoscopy revealed oedema of the submucosa, without any remarkable changes in the mucosa of the terminal ileum. Histological examination of the terminal ileum revealed infiltration of > 20 eosinophils per high-power field (HPF). These findings aided in diagnosing eosinophilic enteritis. We administered methylprednisolone (500 mg/day) for three days, followed by tapering prednisolone. However, the patient's general condition and hypoalbuminemia failed to improve. Immunoglobulin (Ig) G- CMV and IgM-CMV tests were positive. CMV antigenemia was extremely high. Therefore, we administered ganciclovir intravenously, which improved the patient's condition. Furthermore, azathioprine was administered to taper and discontinue prednisolone without relapse of eosinophilic enteritis. This treatment helped stabilize the patient's condition for approximately four years. CONCLUSION: We present a case of eosinophilic enteritis accompanied by CMV disease during prednisolone treatment. The patient's condition improved after administration of ganciclovir. Azathioprine aided in discontinuing prednisolone and stabilizing the patient's condition for approximately four years.

Visualization of stem cell activity in pancreatic cancer expansion by direct lineage tracing with live imaging.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. Although rigorous efforts identified the presence of 'cancer stem cells (CSCs)' in PDAC and molecular markers for them, stem cell dynamics in vivo have not been clearly demonstrated. Here we focused on Doublecortin-like kinase 1 (Dclk1), known as a CSC marker of PDAC. Using genetic lineage tracing with a dual-recombinase system and live imaging, we showed that Dclk1+ tumor cells continuously provided progeny cells within pancreatic intraepithelial neoplasia, primary and metastatic PDAC, and PDAC-derived spheroids in vivo and in vitro. Furthermore, genes associated with CSC and epithelial mesenchymal transition were enriched in mouse Dclk1+ and human DCLK1-high PDAC cells. Thus, we provided direct functional evidence for the stem cell activity of Dclk1+ cells in vivo, revealing the essential roles of Dclk1+ cells in expansion of pancreatic neoplasia in all progressive stages.

Epithelial EP4 plays an essential role in maintaining homeostasis in colon.

Colonic epithelial cells comprise the mucosal barrier, and their dysfunction promotes microbial invasion from the gut lumen and induces the development of intestinal inflammation. The EP4 receptor is known to mediate the protective effect of prostaglandin (PG) E2 in the gastrointestinal tract; however, the exact role of epithelial EP4 in intestinal pathophysiology remains unknown. In the present study, we aimed to investigate the role of epithelial EP4 in maintaining colonic homeostasis by characterizing the intestinal epithelial cell-specific EP4 knockout (EP4 cKO) mice. Mice harboring the epithelial EP4 deletion showed significantly lower colonic crypt depth and lower numbers of secretory cell lineages, as well as impaired epithelial cells in the colon. Interestingly, EP4-deficient colon epithelia showed a higher number of apoptotic cells. Consistent with the defect in mucosal barrier function of colonic epithelia and secretory cell lineages, EP4 cKO colon stroma showed enhanced immune cell infiltration, which was accompanied by increased production of inflammatory cytokines. Furthermore, EP4-deficient colons were susceptible to dextran sulfate sodium (DSS)-induced colitis. Our study is the first to demonstrate that epithelial EP4 loss resulted in potential "inflammatory" status under physiological conditions. These findings provided insights into the crucial role of epithelial PGE2/EP4 axis in maintaining intestinal homeostasis.

Lineage tracing and targeting of IL17RB+ tuft cell-like human colorectal cancer stem cells.

Cancer stem cell (CSC)-specific markers may be potential therapeutic targets. We previously identified that Dclk1, a tuft cell marker, marks tumor stem cells (TSCs) in mouse intestinal adenomas. Based on the analysis of mouse Dclk1+ tumor cells, we aimed to identify a CSC-specific cell surface marker in human colorectal cancers (hCRCs) and validate the therapeutic effect of targeting it. IL17RB was distinctively expressed by Dclk1+ mouse intestinal tumor cells. Using Il17rb-CreERT2-IRES-EGFP mice, we show that IL17RB marked intestinal TSCs in an IL13-dependent manner. Tuft cell-like cancer cells were detected in a subset of hCRCs. In these hCRCs, lineage-tracing experiments in CRISPR-Cas9-mediated IL17RB-CreERT2 knockin organoids and xenograft tumors revealed that IL17RB marks CSCs that expand independently of IL-13. We observed up-regulation of POU2F3, a master regulator of tuft cell differentiation, and autonomous tuft cell-like cancer cell differentiation in the hCRCs. Furthermore, long-term ablation of IL17RB-expressing CSCs strongly suppressed the tumor growth in vivo. These findings reveal insights into a CSC-specific marker IL17RB in a subset of hCRCs, and preclinically validate IL17RB+ CSCs as a cancer therapeutic target.

Bmi1 marks gastric stem cells located in the isthmus in mice.

In the mammalian stomach, the isthmus has been considered as a stem cell zone. However, various locations and proliferative activities of gastric stem cells have been reported. We focused here on the stem cell marker Bmi1, a polycomb group protein, aiming to elucidate the characteristics of Bmi1-expressing cells in the stomach and to examine their stem cell potential. We investigated the Bmi1-expressing cell lineage in Bmi1-CreERT; Rosa26-YFP, LacZ or Rosa26-Confetti mice. We examined the in vivo and ex vivo effects of Bmi1-expressing cell ablation by using Bmi1-CreERT; Rosa26-iDTR mice. The Bmi1 lineage was also traced during regeneration after high-dose tamoxifen-, irradiation- and acetic acid-induced mucosal injuries. In the lineage-tracing experiments using low-dose tamoxifen, Bmi1-expressing cells in the isthmus of the gastric antrum and corpus provided progeny bidirectionally, towards both the luminal and basal sides over 6 months. In gastric organoids, Bmi1-expressing cells also provided progeny. Ablation of Bmi1-expressing cells resulted in impaired gastric epithelium in both mouse stomach and organoids. After high-dose tamoxifen-induced gastric mucosal injury, Bmi1-expressing cell lineages expanded and fully occupied all gastric glands of the antrum and the corpus within 7 days after tamoxifen injection. After irradiation- and acetic acid-induced gastric mucosal injuries, Bmi1-expressing cells also contributed to regeneration. In conclusion, Bmi1 is a gastric stem cell marker expressed in the isthmus of the antrum and corpus. Bmi1-expressing cells have stem cell potentials, both under physiological conditions and during regeneration after gastric mucosal injuries. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The BRG1/SOX9 axis is critical for acinar cell-derived pancreatic tumorigenesis.

Chromatin remodeler Brahma related gene 1 (BRG1) is silenced in approximately 10% of human pancreatic ductal adenocarcinomas (PDAs). We previously showed that BRG1 inhibits the formation of intraductal pancreatic mucinous neoplasm (IPMN) and that IPMN-derived PDA originated from ductal cells. However, the role of BRG1 in pancreatic intraepithelial neoplasia-derived (PanIN-derived) PDA that originated from acinar cells remains elusive. Here, we found that exclusive elimination of Brg1 in acinar cells of Ptf1a-CreER; KrasG12D; Brg1fl/fl mice impaired the formation of acinar-to-ductal metaplasia (ADM) and PanIN independently of p53 mutation, while PDA formation was inhibited in the presence of p53 mutation. BRG1 bound to regions of the Sox9 promoter to regulate its expression and was critical for recruitment of upstream regulators, including PDX1, to the Sox9 promoter and enhancer in acinar cells. SOX9 expression was downregulated in BRG1-depleted ADMs/PanINs. Notably, Sox9 overexpression canceled this PanIN-attenuated phenotype in KBC mice. Furthermore, Brg1 deletion in established PanIN by using a dual recombinase system resulted in regression of the lesions in mice. Finally, BRG1 expression correlated with SOX9 expression in human PDAs. In summary, BRG1 is critical for PanIN initiation and progression through positive regulation of SOX9. Thus, the BRG1/SOX9 axis is a potential target for PanIN-derived PDA.

Gene expression profile of Dclk1+ cells in intestinal tumors.

BACKGROUND: Accumulating evidence has shown the existence of tumor stem cells with therapeutic potential. Previously, we reported that doublecortin like kinase 1 (Dclk1) marks tumor stem cells but not normal stem cells in the intestine of ApcMin/+ mice, and that Dclk1- and Lgr5-double positive tumor cells are the tumor stem cells of intestinal tumors. AIM: To investigate molecules highly expressed in the Dclk1+ normal intestinal and Dclk1+ tumor cells in ApcMin/+ mice. METHODS: We used microarray analyses to examine the gene expression profile of Dclk1+ cells in both mouse normal intestinal epithelium and ApcMin/+ mouse intestinal tumors. We also performed immunofluorescence analyses. RESULTS: Genes related to microtubules and the actin cytoskeleton (e.g., Rac2), and members of the Src family kinases (i.e., Hck, Lyn, Csk, and Ptpn6) were highly expressed in both Dclk1+ normal intestinal and Dclk1+ tumor cells. Phosphorylated Hck and phosphorylated Lyn were expressed in Lgr5+ cells in the intestinal tumors of Lgr5EGFP-IRES-CreERT2/+; ApcMin/+ mice. CONCLUSION: We revealed factors that are highly expressed in Dclk1+ intestinal tumor cells, which may help to develop cancer stem cell-targeted therapy in future.

[A tumor stem cell-specific marker identified by lineage tracing in the intestine].

Tumor therapies targeting tumor stem cells(TSCs) have been limited. One of the reasons is that TSC markers are often shared by normal stem cells (NSCs), and therapies targeting those marker-positive cells may cause severe injury to normal tissues. To solve the problem, we focused on doublecortin -like kinase 1 (Dclk1). In the normal intestines of Dclk1(creERT2/+); Rosa26(LacZ/+) mice, LacZ-labeled epithelial cells were scattered along villi after tamoxifen injection. In contrast, in Dclk1(creERT2/+); Rosa26(LacZ/+); Apc(Min/+) mice, intestinal tumors were occupied by LacZ-labeled tumor cells, and selective ablation of Dclk1-positive cells using iDTR system resulted in regression of intestinal tumors without apparent damage to the normal intestines. Thus, Dclk1 appeared to be a marker that discriminates TSCs from NSCs in the intestine.

Dclk1 distinguishes between tumor and normal stem cells in the intestine.

There is great interest in tumor stem cells (TSCs) as potential therapeutic targets; however, cancer therapies targeting TSCs are limited. A drawback is that TSC markers are often shared by normal stem cells (NSCs); thus, therapies that target these markers may cause severe injury to normal tissues. To identify a potential TSC-specific marker, we focused on doublecortin-like kinase 1 (Dclk1). Dclk1 was reported as a candidate NSC marker in the gut, but recent reports have implicated it as a marker of differentiated cells (for example, Tuft cells). Using lineage-tracing experiments, we show here that Dclk1 does not mark NSCs in the intestine but instead marks TSCs that continuously produce tumor progeny in the polyps of Apc(Min/+) mice. Specific ablation of Dclk1-positive TSCs resulted in a marked regression of polyps without apparent damage to the normal intestine. Our data suggest the potential for developing a therapy for colorectal cancer based on targeting Dclk1-positive TSCs.

Sinusoidal obstructive syndrome with hypereosinophilia successfully treated with prednisolone.

A 60-year-old man was admitted to Tenri Hospital complaining of erythema and abdominal distention. There were marked liver damage and hypereosinophilia. The patient was suffering from portal hypertension and coagulation disorder. We diagnosed the patient clinically as suffering from veno-occlusive disease, or sinusoidal obstructive syndrome (SOS). The pathological finding of the liver biopsy specimen was compatible with SOS. All of the manifestations, liver function test, and hemodynamics subsided shortly after administration of steroid treatment and ursodeoxycholic acid. The pathogenesis was not identified but some allergic reaction was suspected.

[A case of jejunal adenocarcinoma with serum DUPAN-2 elevation].

A 50-year-old woman was admitted to our hospital because of abdominal pain and vomiting. Ileus with ulcerated jejunal tumor was diagnosed and biopsy revealed adenocarcinoma. Because her serum level of DUPAN-2 was high, she was examined by PET scan, which revealed that she had a left ovarian mass in addition to the jejunal tumor. Surgical resection was performed: both tumors were adenocarcinoma, but the ovarian tumor was considered to be metastatic clinically and histologically. Immunostaining for DUPAN-2 was positive in the both tumors. The serum level of DUPAN-2 returned to normal after the surgery, and has been within normal limits for about 3 years without any additional therapy. This case shows a possible relation between small bowel adenocarcinoma and DUPAN-2.