Department of Pathophysiology, Chongqing Medical University, Chongqing, China; Department of Histology and Embryology, Chongqing Medical University, Chongqing, China.
Department of Pathophysiology, Chongqing Medical University, Chongqing, China.
Life Sci. 2020 Jun 1;250:117561. doi: 10.1016/j.lfs.2020.117561. Epub 2020 Mar 19.
Pyruvate kinase M2 (PKM2), a unique isoform of the pyruvate kinases, not only acts as a crucial metabolic enzyme when it locates in the cytoplasm, but also plays important roles in tumor formation and growth when it accumulates in the nuclei. Our aim was to investigate the potential role of PKM2 in liver regeneration in mice insulted with carbon tetrachloride (CCl).
The liver regeneration model was established by intraperitoneal injection of CCl for 48 h in male BALB/c mice. The expression of PKM2, phospho-STAT3, STAT3, proliferating cell nuclear antigen (PCNA) and Cyclin D1 were evaluated by western blot. The distribution of PKM2 was verified by immunofluorescence staining. The degree of injured region was assessed by hematoxylin and eosin (HE) staining. The proliferation of liver cells was tested by Immunohistochemistry.
The nuclear accumulation of PKM2 increased in the liver treated with CCl, but treatment with ML-265 significantly suppressed CCl-induced nuclear accumulation of PKM2. In addition, treatment with ML-265 suppressed the level of cyclin D1 and proliferating cell nuclear antigen (PCNA), reduced the count of Ki67-positive hepatocytes, and expanded the damaged region in histological examination. Meanwhile, treatment with ML-265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3). Inhibition of STAT3 by stattic made the same effects as ML-265.
These data uncovered the role of nuclear PKM2 in liver regeneration and the pro-proliferation effects of nuclear PKM2 may be through targeting its downstream transcription factor STAT3.
丙酮酸激酶 M2（PKM2）是丙酮酸激酶的一种独特同工酶，不仅在细胞质中作为关键代谢酶发挥作用，而且在积聚到核内时在肿瘤形成和生长中发挥重要作用。我们的目的是研究 PKM2 在四氯化碳（CCl）损伤的小鼠肝脏再生中的潜在作用。
通过在雄性 BALB/c 小鼠的腹腔内注射 CCl 48 小时建立肝脏再生模型。通过 Western blot 评估 PKM2、磷酸化 STAT3、STAT3、增殖细胞核抗原（PCNA）和细胞周期蛋白 D1 的表达。通过免疫荧光染色验证 PKM2 的分布。通过苏木精和伊红（HE）染色评估损伤区域的程度。通过免疫组化测试肝细胞的增殖。
CCl 处理后肝脏中 PKM2 的核内积累增加，但 ML-265 处理显著抑制了 CCl 诱导的 PKM2 核内积累。此外，ML-265 处理抑制了细胞周期蛋白 D1 和增殖细胞核抗原（PCNA）的水平，减少了 Ki67 阳性肝细胞的数量，并在组织学检查中扩大了受损区域。同时，ML-265 抑制了核信号转导和转录激活因子 3（STAT3）的磷酸化。STAT3 的抑制剂 stattic 产生了与 ML-265 相同的效果。
这些数据揭示了核 PKM2 在肝脏再生中的作用，核 PKM2 的促增殖作用可能是通过靶向其下游转录因子 STAT3 实现的。
