Schmelzer Eva, Foka Hubert G, Thompson Robert L, Luca Angelo, Gridelli Bruno, Gerlach Jörg C
1 Department of Surgery, McGowan Institute for Regenerative Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania.
2 University of Pittsburgh Medical Center, University of Pittsburgh , Pittsburgh, Pennsylvania.
Rejuvenation Res. 2018 Jun;21(3):257-269. doi: 10.1089/rej.2016.1890. Epub 2017 Oct 23.
Prolonged physiological stresses, including abnormal pH and temperature, are deleterious. However, human hepatic progenitors have been shown to be quite tolerant of temporary temperature stress such as in cold ischemia. We aimed at identifying how various stresses affect liver progenitors, and at determining whether distinct effects exist on different progenitor cells of the human liver. Total fetal liver cells were exposed to low (25°C), normal (37°C), or high (40°C) temperatures, or low (6.76), normal (7.35), or high (7.88) pH in vitro. Culture at 25°C increased cell numbers and percentages of proliferation marker Ki67 total cells. In total cell cultures, percentages of CD326 hepatic progenitors co-expressing DLK1 (delta-like 1 homolog), SSEA4, or CD90 increased, as well as proliferation of SSEA4 and CD235a progenitors. Analyses of presorted hepatic progenitors revealed that culture at 25°C increased cell numbers of CD326 hepatic stem/progenitor cells but not DLK hepatoblasts. The expression of several mesenchymal genes was reduced, and distinct hepatic stem/progenitor cell colonies emerged. At 40°C, numbers of adherent hepatic cells decreased but those of hematopoietic nonadherent cells increased. High pH did not cause major effects. Acidic pH resulted in decreased total cell numbers and affected hematopoietic cells. Percentages of DLK1 hepatoblasts were increased, but those of hematopoietic mature CD45 cells were decreased. In particular, proliferation of adherent hepatic CD326, SSEA4 progenitors, and hematopoietic CD45 cells and CD235a erythroblasts was reduced. Conclusively, our data indicate that low-temperature stress stimulates hepatic progenitor and erythroblast proliferation, whereas acidic pH promotes hepatic maturation and reduces hematopoietic cells.
长期的生理应激，包括异常的pH值和温度，是有害的。然而，人类肝脏祖细胞已被证明对诸如冷缺血等暂时性温度应激具有相当的耐受性。我们旨在确定各种应激如何影响肝脏祖细胞，并确定对人类肝脏不同祖细胞是否存在不同影响。将总胎肝细胞在体外暴露于低温（25°C）、正常温度（37°C）或高温（40°C），或低pH值（6.76）、正常pH值（7.35）或高pH值（7.88）环境中。在25°C培养可增加细胞数量以及增殖标志物Ki67阳性总细胞的百分比。在总细胞培养物中，共表达DLK1（类Delta样1同源物）、SSEA4或CD90的CD326肝脏祖细胞百分比增加，以及SSEA4和CD235a祖细胞的增殖增加。对预分选的肝脏祖细胞的分析表明，在25°C培养可增加CD326肝脏干/祖细胞的数量，但不会增加DLK成肝细胞的数量。几种间充质基因的表达降低，并且出现了不同的肝脏干/祖细胞集落。在40°C时，贴壁肝细胞数量减少，但造血非贴壁细胞数量增加。高pH值未产生重大影响。酸性pH值导致总细胞数量减少，并影响造血细胞。DLK1成肝细胞的百分比增加，但造血成熟CD45细胞的百分比降低。特别是，贴壁肝脏CD326、SSEA4祖细胞以及造血CD45细胞和CD235a成红细胞的增殖减少。总之，我们的数据表明，低温应激刺激肝脏祖细胞和成红细胞增殖，而酸性pH值促进肝脏成熟并减少造血细胞。
