Loss of GATA4 causes ectopic pancreas in the stomach

Highlights of how single-cell analyses are illuminating differentiation and disease in the gastric corpus

Single-cell RNA-sequencing (scRNA-seq) has emerged as a powerful technique to identify novel cell markers, developmental trajectories, and transcriptional changes during cell differentiation and disease onset and progression. In this review, we highlight recent scRNA-seq studies of the gastric corpus in both human and murine systems that have provided insight into gastric organogenesis, identified novel markers for the various gastric lineages during development and in adults, and revealed transcriptional changes during regeneration and tumorigenesis. Overall, by elucidating transcriptional states and fluctuations at the cellular level in healthy and disease contexts, scRNA-seq may lead to better, more personalized clinical treatments for disease progression.

Overview of ectopic pancreas

This editorial discusses the article written by Zheng et al that was published in the latest edition of the World Journal of Gastrointestinal Surgery. Our primary focus is on the causes, location, diagnosis, histological classification, and therapy of ectopic pancreas. Ectopic pancreas refers to the presence of pancreatic tissue that is situated in a location outside its usual anatomical placement, and is not connected to the normal pancreas in terms of blood supply or anatomical structure. Currently, the embryological origin of ectopic pancreas remains uncertain. The most prevalent form of ectopic pancreatic is gastric ectopic pancreas. Endoscopic ultrasonography examination can visualize the morphological characteristics of the ectopic pancreatic lesion and pinpoint its anatomical location. The histological categorization of ectopic pancreas evolves. Endoscopic treatment has been widely advocated in ectopic pancreas.

Laparoscopic resection and endoscopic submucosal dissection for treating gastric ectopic pancreas

BACKGROUND

Gastric ectopic pancreas (GEP) is a rare developmental abnormality that refers to the existence of pancreatic tissue in the stomach with no anatomical relationship with the main pancreas. It is usually difficult to diagnose through histological examination, and the choice of treatment method is crucial.

AIM

To describe the endoscopic ultrasound characteristics of GEP and evaluate the value of laparoscopic resection (LR) and endoscopic submucosal dissection (ESD).

METHODS

Forty-nine patients with GEP who underwent ESD and LR in the Second Affiliated Hospital of Fujian Medical University from May 2018 to July 2023 were retrospectively included. Data on clinical characteristics, endoscopic ultrasonography (EUS), ESD, and LR were collected and analyzed. The characteristics of EUS and the efficacy of the two treatments were analyzed.

RESULTS

The average age of the patients was 43.31 ± 13.50 years, and the average maximum diameter of the lesions was 1.55 ± 0.70 cm. The lesion originated from the mucosa in one patient (2.04%), from the submucosa in 42 patients (85.71%), and from the muscularis propria in 6 patients (12.25%). Twenty-nine patients (59.20%) with GEP showed umbilical depression on endoscopy. The most common initial symptom of GEP was abdominal pain (40.82%). Tumor markers, including carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA-19-9), were generally within the normal range. One patient (2.04%) with GEP had increased CEA and CA-19-9 levels. However, no cancer tissue was found on postoperative pathological examination, and tumor markers returned to normal levels after resecting the lesion. There was no significant difference in surgery duration (72.42 ± 23.84 vs 74.17 ± 12.81 min) or hospital stay (3.70 ± 0.91 vs 3.83 ± 0.75 d) between the two methods. LR was more often used for patients with larger tumors and deeper origins. The amount of bleeding was significantly higher in LR than in ESD (11.28 ± 16.87 vs 16.67 ± 8.76 mL, P < 0.05). Surgery was associated with complete resection of the lesion without any serious complications; there were no cases of recurrence during the follow-up period.

CONCLUSION

GEP has unique characteristics in EUS. LR and ESD seem to be good choices for treating GEP. LR is better for large GEP with a deep origin. However, due to the rarity of GEP, multicenter large-scale studies are needed to describe its characteristics and evaluate the safety of LR and ESD.

GATA4 and GATA6 loss-of-expression is associated with extinction of the classical programme and poor outcome in pancreatic ductal adenocarcinoma

OBJECTIVE

GATA6 is a key regulator of the classical phenotype in pancreatic ductal adenocarcinoma (PDAC). Low GATA6 expression associates with poor patient outcome. GATA4 is the second most expressed GATA factor in the pancreas. We assessed whether, and how, GATA4 contributes to PDAC phenotype and analysed the association of expression with outcome and response to chemotherapy.

DESIGN

We analysed PDAC transcriptomic data, stratifying cases according to GATA4 and GATA6 expression and identified differentially expressed genes and pathways. The genome-wide distribution of GATA4 was assessed, as well as the effects of GATA4 knockdown. A multicentre tissue microarray study to assess GATA4 and GATA6 expression in samples (n=745) from patients with resectable was performed. GATA4 and GATA6 levels were dichotomised into high/low categorical variables; association with outcome was assessed using univariable and multivariable Cox regression models.

RESULTS

GATA4 messenger RNA is enriched in classical, compared with basal-like tumours. We classified samples in 4 groups as high/low for GATA4 and GATA6. Reduced expression of GATA4 had a minor transcriptional impact but low expression of GATA4 enhanced the effects of GATA6 low expression. GATA4 and GATA6 display a partially overlapping genome-wide distribution, mainly at promoters. Reduced expression of both proteins in tumours was associated with the worst patient survival. GATA4 and GATA6 expression significantly decreased in metastases and negatively correlated with basal markers.

CONCLUSIONS

GATA4 and GATA6 cooperate to maintain the classical phenotype. Our findings provide compelling rationale to assess their expression as biomarkers of poor prognosis and therapeutic response.

Case report of retroperitoneal ectopic pancreas with adrenal adenoma

Background

Ectopic pancreas is a congenital anomaly in which pancreatic tissue is anatomically separated from the main gland and without vascular or ductal continuity. A case of retroperitoneal ectopic pancreas with adrenal adenoma has never yet been reported.

Case Presentation

A 54-year-old man presented three masses in the left retroperitoneum, and two of them were resected. The pathologic findings were a retroperitoneal ectopic pancreas with adrenal adenoma.

Conclusion

We report an extremely rare case of a retroperitoneal ectopic pancreas and its characterization with dynamic gadolinium-enhanced magnetic resonance imaging (MRI).

GATA4 Controls Epithelial Morphogenesis in the Developing Stomach to Promote Establishment of Glandular Columnar Epithelium

BACKGROUND & AIMS

The transcription factor GATA4 is broadly expressed in nascent foregut endoderm. As development progresses, GATA4 is lost in the domain giving rise to the stratified squamous epithelium of the esophagus and forestomach (FS), while it is maintained in the domain giving rise to the simple columnar epithelium of the hindstomach (HS). Differential GATA4 expression within these domains coincides with the onset of distinct tissue morphogenetic events, suggesting a role for GATA4 in diversifying foregut endoderm into discrete esophageal/FS and HS epithelial tissues. The goal of this study was to determine how GATA4 regulates differential morphogenesis of the mouse gastric epithelium.

METHODS

We used a Gata4 conditional knockout mouse line to eliminate GATA4 in the developing HS and a Gata4 conditional knock-in mouse line to express GATA4 in the developing FS.

RESULTS

We found that GATA4-deficient HS epithelium adopted a FS-like fate, and conversely, that GATA4-expressing FS epithelium adopted a HS-like fate. Underlying structural changes in these epithelia were broad changes in gene expression networks attributable to GATA4 directly activating or repressing expression of HS or FS defining transcripts. Our study implicates GATA4 as having a primary role in suppressing an esophageal/FS transcription factor network during HS development to promote columnar epithelium. Moreover, GATA4-dependent phenotypes in developmental mutants reflected changes in gene expression associated with Barrett's esophagus.

CONCLUSIONS

This study demonstrates that GATA4 is necessary and sufficient to activate the development of simple columnar epithelium, rather than stratified squamous epithelium, in the embryonic stomach. Moreover, similarities between mutants and Barrett's esophagus suggest that developmental biology can provide insight into human disease mechanisms.

Identification and functional study of GATA4 gene regulatory variants in type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2D) is a common and complex disease. Dysfunction of pancreatic β cells, which cannot release sufficient insulin, plays a central role in T2D. Genetics plays a critical role in T2D etiology. Transcription factor GATA4 is required for the pancreatic development, and GATA4 gene mutations are implicated in neonatal or childhood-onset diabetes. In this study, we aimed to investigate whether regulatory variants in GATA4 gene may change GATA4 levels, conferring susceptibility to T2D development.

METHODS

The promoter region of GATA4 gene was analyzed by targeted sequencing in T2D patients (n = 255) and ethnic-matched controls (n = 371). Dual luciferase activity assay was used for functional study, and EMSA (electrophoretic mobility shift assay) was performed for detecting transcription factor binding.

RESULTS

Thirteen regulatory variants including 5 SNPs were identified. A novel heterozygous variant (32124C > T) and one SNP [31487C > G (rs1053351749)] were only identified in T2D. Both regulatory variants significantly affected GATA4 gene promoter activity in cultured HEK-293 and INS-1 cells. Furthermore, the variant (32124C > T) evidently enhanced the binding of unknown transcriptional activator.

CONCLUSIONS

Our data suggested that GATA4 gene regulatory variants may contribute to T2D development as a rare risk factor.