Zhang Yang, Liu Yulong, Wang Yaling
Department of Cardiology, the Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China.
Cell Biochem Biophys. 2025 Jul 18. doi: 10.1007/s12013-025-01819-x.
Myocardial hypertrophy, a complex cardiovascular disorder, remains a significant challenge. NRG4 has shown protective effects against myocardial damage. Here, we clarified the role of NRG4 in angiotensin II (Ang II)-induced hypertrophy of AC16 cardiomyocytes. The Ang II-stimulated AC16 cell line was used as an in vitro model of myocardial hypertrophy. Immunofluorescence using an anti-α-actinin antibody was used to observe cell area and size. mRNA expression was detected by quantitative PCR, and protein levels were measured by immunoblot assay. ROS amount detection was performed by flow cytometry. The cell protein/DNA ratio and the levels of IL-1β, IL-18, MDA and SOD were tested using commercial kits. The relationship between PCBP2 and NRG4 mRNA was validated by luciferase, RNA immunoprecipitation (RIP), and mRNA stability assays. In Ang II-stimulated AC16 cells, PCBP2 and NRG4 were markedly downregulated. Increased NRG4 expression relieved Ang II-induced hypertrophy and fibrosis in AC16 cardiomyocytes. Moreover, NRG4 increase weakened NLRP3 inflammasome activation and oxidative stress in Ang II-stimulated AC16 cardiomyocytes. Mechanistically, PCBP2 stabilized NRG4 mRNA to increase NRG4 protein expression in Ang II-induced AC16 cardiomyocytes. NRG4 depletion counteracted the suppressive effects of PCBP2 upregulation on hypertrophy, NLRP3 inflammasome activation, and oxidative stress of Ang II-induced AC16 cardiomyocytes. Additionally, the PCBP2/NRG4 cascade regulated the AMPK/mTOR signaling pathway in Ang II-induced AC16 cardiomyocytes. Our data demonstrate that the previously uncharacterized PCBP2/NRG4 cascade attenuates Ang II-triggered hypertrophy, NLRP3 inflammasome activation, and oxidative stress of AC16 cardiomyocytes.
心肌肥大是一种复杂的心血管疾病，仍然是一个重大挑战。NRG4已显示出对心肌损伤的保护作用。在此，我们阐明了NRG4在血管紧张素II（Ang II）诱导的AC16心肌细胞肥大中的作用。将Ang II刺激的AC16细胞系用作心肌肥大的体外模型。使用抗α-辅肌动蛋白抗体的免疫荧光法观察细胞面积和大小。通过定量PCR检测mRNA表达，通过免疫印迹法测量蛋白质水平。通过流式细胞术进行ROS量检测。使用商业试剂盒检测细胞蛋白质/DNA比率以及IL-1β、IL-18、MDA和SOD水平。通过荧光素酶、RNA免疫沉淀（RIP）和mRNA稳定性测定验证PCBP2与NRG4 mRNA之间的关系。在Ang II刺激的AC16细胞中，PCBP2和NRG4明显下调。NRG4表达增加可减轻Ang II诱导的AC16心肌细胞肥大和纤维化。此外，NRG4增加减弱了Ang II刺激的AC16心肌细胞中NLRP3炎性小体的激活和氧化应激。机制上，PCBP2稳定NRG4 mRNA以增加Ang II诱导的AC16心肌细胞中NRG4蛋白表达。NRG4缺失抵消了PCBP2上调对Ang II诱导的AC16心肌细胞肥大、NLRP3炎性小体激活和氧化应激的抑制作用。此外，PCBP2/NRG4级联调节Ang II诱导的AC16心肌细胞中的AMPK/mTOR信号通路。我们的数据表明，先前未被表征的PCBP2/NRG4级联减弱了Ang II引发的AC16心肌细胞肥大、NLRP3炎性小体激活和氧化应激。
