Identification of Stem Cells in the Epithelium of the Stomach Corpus and Antrum of Mice

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• 作者：Junichi Matsuo¹ ; ^&lowast ; ; Shunichi Kimura¹ ; ² ; ^&lowast ; ; Akihiro Yamamura¹ ; ² ; ^&lowast ; ; Cai Ping Koh¹ ; Md Zakir Hossain¹ ; Dede Liana Heng¹ ; Kazuyoshi Kohu¹ ; Dominic Chih-Cheng Voon¹ ; Hiroshi Hiai³ ; Michiaki Unno² ; Jimmy Bok Yan So⁴ ; Feng Zhu⁵ ; Supriya Srivastava¹ ; Ming Teh⁶ ; Khay Guan Yeoh⁵ ; ⁷ ; Motomi Osato¹ ; ⁸ ; ⁹ ; ¹⁰ ; ^{csimo@nus.edu.sg} ; Yoshiaki Ito¹ ; ⁵ ; ^{csiitoy@nus.edu.sg}
• 关键词：Stomach Cancer ; Mouse Model ; Cancer Stem Cell ; Oncogene
• 刊名：Gastroenterology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：152
• 期：1
• 页码：218-231.e14
• 全文大小：16273 K
• 卷排序：152

文摘

Little is known about the mechanisms of gastric carcinogenesis, partly because it has been a challenge to identify characterize gastric stem cells. Runx genes regulate development and their products are transcription factors associated with cancer development. A Runx1 enhancer element, eR1, is a marker of hematopoietic stem cells. We studied expression from eR1 in the stomach and the roles of gastric stem cells in gastric carcinogenesis in transgenic mice.MethodsWe used in situ hybridization and immunofluorescence analyses to study expression of Runx1 in gastric tissues from C57BL/6 (control) mice. We then created mice that expressed enhanced green fluorescent protein (EGFP) or CreERT2 under the control of eR1 (eR1-CreERT2;Rosa-Lox-Stop-Lox [LSL]-tdTomato, eR1-CreERT2;Rosa-LSL-EYFP mice). Gastric tissues were collected and lineage-tracing experiments were performed. Gastric organoids were cultured from eR1-CreERT2(5-2);Rosa-LSL-tdTomato mice and immunofluorescence analyses were performed. We investigated the effects of expressing oncogenic mutations in stem cells under control of eR1 using eR1-CreERT2;LSL-KrasG12D/+ mice; gastric tissues were collected and analyzed by histology and immunofluorescence.ResultsMost proliferation occurred in the isthmus; 86% of proliferating cells were RUNX1-positive and 76% were MUC5AC-positive. In eR1-EGFP mice, EGFP signals were detected mainly in the upper part of the gastric unit, and 83% of EGFP-positive cells were located in the isthmus/pit region. We found that eR1 marked undifferentiated stem cells in the isthmus and a smaller number of terminally differentiated chief cells at the base. eR1 also marked cells in the pyloric gland in the antrum. Lineage-tracing experiments demonstrated that stem cells in the isthmus and antrum continuously gave rise to mature cells to maintain the gastric unit. eR1-positive cells in the isthmus and pyloric gland generated organoid cultures in vitro. In eR1-CreERT2;LSL-Kras G12D/+ mice, MUC5AC-positive cells rapidly differentiated from stem cells in the isthmus, resulting in distinct metaplastic lesions similar to that observed in human gastric atrophy.ConclusionsUsing lineage-tracing experiments in mice, we found that a Runx1 enhancer element, eR1, promotes its expression in the isthmus stem cells of stomach corpus as well as pyloric gland in the antrum. We were able to use eR1 to express oncogenic mutations in gastric stem cells, proving a new model for studies of gastric carcinogenesis.