Urine-derived stem cells (USCs) are autologous stem cells with self-renewal ability and multi-lineage differentiation potential. Our previous studies have shown that hypoxia preconditioning can improve self-renewal and migration abilities of USCs by up-regulating autophagy. The purpose of this study was to investigate the specific mechanism by which hypoxia treatment promotes the biological function of USCs. We found that hypoxia treatment upregulated the expression of phosphralated ERK protein without affecting the expression of total ERK protein. Inhibiting ERK signaling with the PD98059 inhibitor decreased cell proliferation, migration and colony formation during hypoxia treatment. Hypoxia increased ATP production, mitochondrial membrane potential and mt-DNA copy number, which were reversed by inhibiting the ERK signal. Additionally, the number of autophagosomes and autophagic lysosomes was significantly lower in PD98059 group than in the hypoxia group. PD98059 treatment inhibited the up-regulation of autophagy related proteins induced by hypoxia. Therefore, this study suggests that hypoxia improves the self-renewal and migration abilities of USCs by upregulating autophagy and mitochondrial function through ERK signaling pathway. This finding may provide a new therapeutic mechanism for hypoxia pretreated USCs as a source of stem cell transplantation.

尿源性干细胞（USC）是具有自我更新能力和多谱系分化潜力的自体干细胞。我们前期的研究表明，缺氧预处理可以通过上调自噬来提高USCs的自我更新和迁移能力。本研究的目的是探讨缺氧治疗促进USCs生物学功能的具体机制。我们发现缺氧处理上调了磷酸化ERK蛋白的表达，但不影响总ERK蛋白的表达。使用 PD98059 抑制剂抑制 ERK 信号传导可减少缺氧治疗期间的细胞增殖、迁移和集落形成。缺氧会增加 ATP 的产生、线粒体膜电位和 mt-DNA 拷贝数，但通过抑制 ERK 信号可以逆转这些现象。此外，PD98059组自噬体和自噬溶酶体的数量显着低于缺氧组。PD98059治疗抑制了缺氧诱导的自噬相关蛋白的上调。因此，本研究表明缺氧通过ERK信号通路上调自噬和线粒体功能，从而提高USCs的自我更新和迁移能力。这一发现可能为缺氧预处理的 USCs 作为干细胞移植来源提供新的治疗机制。