Erythropoietin (EPO), a central protein of erythropoiesis, plays an important role during hypoxia adaptation and is regulated by hypoxia-inducible factor (HIF). However, there is no report on EPO-producing cells and their regulatory mechanisms in yak (Bos grunniens). To understand EPO production and regulation of yak, kidneys from different age of yak were collected and expression of EPO, hypoxia-inducible factor 1 alpha (HIF-1α), and hypoxia-inducible factor 2 alpha (HIF-2α) were detected. Then renal tubule epithelial cells (RTECs) and peritubular interstitial fibroblast-like (RIFs) cells were isolated and cultured to determine their EPO production abilities. Subsequently, the cells were treated with dimethyloxalylglycine (DMOG) and Geldanamycin (GA), which are inhibitors of prolyl-4-hydroxylase domain (PHD) and heat shock protein 90 (HSP90) respectively, and siRNAs of HIF-1α and HIF-2α to explore their effect on EPO production and regulation. The results showed that expressions of EPO, HIF-1α, and HIF-2α were different in the different age groups of yak. High DMOG concentration caused a corresponding increase in the levels of HIF-1α and HIF-2α in RIFs and RTECs, however, EPO levels increased in RIFs only and was not detected at any concentration in RTECs; suggesting that EPO was produced in RIFs. Upon treating RIFs with siRNAs of HIF-1α and HIF-2α, we found that EPO was regulated by PHD through HIF-2α. In addition, increasing GA concentration caused a decrease in expression of HSP90, HIF-1α, HIF-2α, and EPO in RIFs. In conclusion, these findings support our proposition that PHD regulates EPO via HIF-2α in yak RIFs, while HSP90 impelled EPO expression.

促红细胞生成素（EPO）是红细胞生成的中心蛋白，在缺氧适应过程中起重要作用，受缺氧诱导因子（HIF）的调节。然而，没有关于牦牛（Bos grunniens ）中产生EPO的细胞及其调控机制的报道。）。为了了解牦牛 EPO 的产生和调控，收集了不同年龄牦牛的肾脏，检测了 EPO、缺氧诱导因子 1 α（HIF-1α）和缺氧诱导因子 2 α（HIF-2α）的表达。然后分离和培养肾小管上皮细胞（RTECs）和肾小管周间质成纤维细胞样（RIFs）细胞，以确定它们的EPO产生能力。随后，用二甲基乙二酰甘氨酸 (DMOG) 和格尔德霉素 (GA) 处理细胞，它们分别是脯氨酰-4-羟化酶结构域 (PHD) 和热休克蛋白 90 (HSP90) 的抑制剂，以及 HIF-1α 和 HIF-2α 的 siRNA探索它们对 EPO 产生和调节的影响。结果表明，牦牛不同年龄组的EPO、HIF-1α、HIF-2α表达不同。高 DMOG 浓度导致 RIF 和 RTECs 中 HIF-1α 和 HIF-2α 水平相应增加，然而，EPO 水平仅在 RIFs 中增加，并且在 RTECs 中的任何浓度下均未检测到；表明 EPO 是在 RIF 中产生的。在用 HIF-1α 和 HIF-2α 的 siRNA 处理 RIF 后，我们发现 EPO 受 PHD 通过 HIF-2α 调节。此外，增加 GA 浓度会导致 RIF 中 HSP90、HIF-1α、HIF-2α 和 EPO 的表达降低。总之，这些发现支持我们的主张，即 PHD 通过牦牛 RIF 中的 HIF-2α 调节 EPO，而 HSP90 促进 EPO 表达。我们发现 EPO 受 PHD 通过 HIF-2α 调节。此外，增加 GA 浓度会导致 RIF 中 HSP90、HIF-1α、HIF-2α 和 EPO 的表达降低。总之，这些发现支持我们的主张，即 PHD 通过牦牛 RIF 中的 HIF-2α 调节 EPO，而 HSP90 促进 EPO 表达。我们发现 EPO 受 PHD 通过 HIF-2α 调节。此外，增加 GA 浓度会导致 RIF 中 HSP90、HIF-1α、HIF-2α 和 EPO 的表达降低。总之，这些发现支持我们的主张，即 PHD 通过牦牛 RIF 中的 HIF-2α 调节 EPO，而 HSP90 促进 EPO 表达。