Van Landeghem Laurianne, Santoro M Agostina, Mah Amanda T, Krebs Adrienne E, Dehmer Jeffrey J, McNaughton Kirk K, Helmrath Michael A, Magness Scott T, Lund P Kay
*Department of Cell Biology and Physiology, Department of Nutrition, Department of Surgery, and Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA; and University of North Carolina/North Carolina State Biomedical Engineering, Chapel Hill, North Carolina, USA.
*Department of Cell Biology and Physiology, Department of Nutrition, Department of Surgery, and Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA; and University of North Carolina/North Carolina State Biomedical Engineering, Chapel Hill, North Carolina, USA
FASEB J. 2015 Jul;29(7):2828-42. doi: 10.1096/fj.14-264010. Epub 2015 Apr 2.
Insulin-like growth factor 1 (IGF1) has potent trophic effects on normal or injured intestinal epithelium, but specific effects on intestinal stem cells (ISCs) are undefined. We used Sox9-enhanced green fluorescent protein (EGFP) reporter mice that permit analyses of both actively cycling ISCs (Sox9-EGFP(Low)) and reserve/facultative ISCs (Sox9-EGFP(High)) to study IGF1 action on ISCs in normal intestine or during crypt regeneration after high-dose radiation-induced injury. We hypothesized that IGF1 differentially regulates proliferation and gene expression in actively cycling and reserve/facultative ISCs. IGF1 was delivered for 5 days using subcutaneously implanted mini-pumps in uninjured mice or after 14 Gy abdominal radiation. ISC numbers, proliferation, and transcriptome were assessed. IGF1 increased epithelial growth in nonirradiated mice and enhanced crypt regeneration after radiation. In uninjured and regenerating intestines, IGF1 increased total numbers of Sox9-EGFP(Low) ISCs and percentage of these cells in M-phase. IGF1 increased percentages of Sox9-EGFP(High) ISCs in S-phase but did not expand this population. Microarray revealed that IGF1 activated distinct gene expression signatures in the 2 Sox9-EGFP ISC populations. In vitro IGF1 enhanced enteroid formation by Sox9-EGFP(High) facultative ISCs but not Sox9-EGFP(Low) actively cycling ISCs. Our data provide new evidence that IGF1 activates 2 ISC populations via distinct regulatory pathways to promote growth of normal intestinal epithelium and crypt regeneration after irradiation.
胰岛素样生长因子1（IGF1）对正常或受损的肠上皮具有强大的营养作用，但对肠干细胞（ISC）的具体作用尚不清楚。我们使用了Sox9增强型绿色荧光蛋白（EGFP）报告基因小鼠，该小鼠可对活跃循环的ISC（Sox9-EGFP（低））和储备/兼性ISC（Sox9-EGFP（高））进行分析，以研究IGF1对正常肠道或高剂量辐射诱导损伤后隐窝再生期间ISC的作用。我们假设IGF1对活跃循环的ISC和储备/兼性ISC的增殖和基因表达有不同的调节作用。在未受伤的小鼠或接受14 Gy腹部辐射后，使用皮下植入的微型泵给予IGF1 5天。评估ISC数量、增殖和转录组。IGF1增加了未受辐射小鼠的上皮生长，并增强了辐射后的隐窝再生。在未受伤和再生的肠道中，IGF1增加了Sox9-EGFP（低）ISC的总数及其在M期的细胞百分比。IGF1增加了Sox9-EGFP（高）ISC在S期的百分比，但没有扩大这一群体。微阵列显示，IGF1在2个Sox9-EGFP ISC群体中激活了不同的基因表达特征。在体外，IGF1增强了Sox9-EGFP（高）兼性ISC形成肠样结构的能力，但没有增强Sox9-EGFP（低）活跃循环ISC的能力。我们的数据提供了新的证据，即IGF1通过不同的调节途径激活2个ISC群体，以促进正常肠上皮的生长和辐射后的隐窝再生。
