Lactic acid bacteria (LAB) in the gastrointestinal tract have beneficial health effects. LAB activate the proliferation of intestinal stem cells and speed the recovery of damaged intestinal cells, but little is known about effect of LAB on other adult stem cells. In this study, a cell-free extract of Enterococcus faecium L-15 (L15) was exposed to mouse skin-derived precursor cells (SKPs), and the changes in characteristics associated with proliferation and self-renewal capacity were investigated. L15 increased the size of the spheres and the proliferation rate of SKPs. Cell cycle analysis revealed that cells in the S-phase increased after treatment with L15. In the L15-treated group, the total number of spheres significantly increased. The expression level of pluripotency marker genes also increased, while the mesenchymal lineage-related differentiation marker genes significantly decreased in the L15-treated group. The PI3K/Akt signaling pathway was activated by L15 in SKPs. These results indicate that L15 enhances proliferation and self-renewal of SKPs and may be used as a supplement for stem cell maintenance or application of stem cell therapy. This is the first report to investigate the functional effects of E. faecium on the proliferation and self-renewal capacity of SKPs.

胃肠道中的乳酸菌（LAB）对健康有益。LAB可激活肠道干细胞的增殖并加速受损肠细胞的恢复，但关于LAB对其他成体干细胞的作用知之甚少。在这项研究中，粪肠球菌的无细胞提取物L-15（L15）暴露于小鼠皮肤衍生的前体细胞（SKP），并研究了与增殖和自我更新能力相关的特征变化。L15增加了球体的大小和SKP的扩散率。细胞周期分析显示，用L15处理后，S期细胞增加。在L15治疗组中，球的总数显着增加。在L15治疗组中，多能性标记基因的表达水平也增加，而间充质谱系相关的分化标记基因显着降低。L3在SKP中激活了PI3K / Akt信号通路。这些结果表明L15增强SKP的增殖和自我更新，并且可以用作干细胞维持或干细胞疗法应用的补充。E. faecium对SKPs的增殖和自我更新的能力。