Kojima Hideto, Nakamura Takaaki, Fujita Yukihiro, Kishi Akio, Fujimiya Mineko, Yamada Syu, Kudo Motoi, Nishio Yoshihiko, Maegawa Hiroshi, Haneda Masakazu, Yasuda Hitoshi, Kojima Itaru, Seno Masaharu, Wong Norman C W, Kikkawa Ryuichi, Kashiwagi Atsunori
Third Department of Medicine, Shiga University of Medical Science, Shiga, Japan.
Diabetes. 2002 May;51(5):1398-408. doi: 10.2337/diabetes.51.5.1398.
Immature rat intestinal stem cells (IEC-6) given the ability to express the transcription factor, pancreatic duodenal homeobox 1 (Pdx-1), yielded YK cells. Although these cells produced multiple enteroendocrine hormones, they did not produce insulin. Exposure of YK cells to 2 nmol/l betacellulin yielded BYK cells that showed the presence of insulin expression in cytoplasm and that secreted insulin into culture media. By examining the mechanism of differentiation in BYK cells, we found that another transcription factor, islet factor 1 (Isl-1) was newly expressed with the disappearance of Pax-6 expression in those cells after exposure to betacellulin. These results indicated that combined expression of Pdx-1 and Isl-1 in IEC-6 cells was required for the production of insulin. In fact, overexpression of both Pdx-1 and Isl-1 in IEC-6 cells (Isl-YK-12, -14, and -15 cells) gave them the ability to express insulin without exposure to betacellulin. Furthermore, implantation of the Isl-YK-14 cells into diabetic rats reduced the animals' plasma glucose levels; glucose levels dropped from 19.4 to 16.9 mmol/l 1 day after the injection of cells. As expected, the plasma insulin concentrations were 2.7 times higher in the diabetic rats injected with Isl-YK-14 cells compared to in controls. In summary, our results indicated that immature intestinal stem cells can differentiate into insulin-producing cells given the ability to express the transcription factors Pdx-1 and Isl-1.
赋予未成熟大鼠肠道干细胞（IEC-6细胞）表达转录因子胰腺十二指肠同源盒1（Pdx-1）的能力后，得到了YK细胞。尽管这些细胞能产生多种肠内分泌激素，但它们不产生胰岛素。将YK细胞暴露于2 nmol/l的β细胞ulin中，产生了BYK细胞，这些细胞的细胞质中出现了胰岛素表达，并将胰岛素分泌到培养基中。通过研究BYK细胞的分化机制，我们发现，在暴露于β细胞ulin后，这些细胞中另一种转录因子胰岛因子1（Isl-1）新表达，同时Pax-6表达消失。这些结果表明，IEC-6细胞中Pdx-1和Isl-1的联合表达是产生胰岛素所必需的。事实上，在IEC-6细胞（Isl-YK-12、-14和-15细胞）中同时过表达Pdx-1和Isl-1，使它们在未暴露于β细胞ulin的情况下也有表达胰岛素的能力。此外，将Isl-YK-14细胞植入糖尿病大鼠体内可降低动物的血糖水平；注射细胞1天后，血糖水平从19.4 mmol/l降至16.9 mmol/l。正如预期的那样，注射Isl-YK-14细胞的糖尿病大鼠的血浆胰岛素浓度比对照组高2.7倍。总之，我们的结果表明，未成熟的肠道干细胞在具备表达转录因子Pdx-1和Isl-1的能力后可分化为胰岛素产生细胞。
