Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang 050017, China.
Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang 050017, China; Department of Urology, Second Hospital of Hebei Medical University 050000, China.
J Adv Res. 2022 Jul;39:103-117. doi: 10.1016/j.jare.2021.10.007. Epub 2021 Oct 20.
Hypoxia-inducible factor (HIF)1α has been shown to be activated and induces a glycolytic shift under hypoxic condition, however, little attention was paid to the role of HIF1α-actuated fructolysis in hypoxia-induced heart injury.
In this study, we aim to explore the molecular mechanisms of miR-155-mediated fructose metabolism in hypoxic cardiac fibroblasts (CFs).
Immunostaining, western blot and quantitative real-time reverse transcription PCR (qRT-PCR) were performed to detect the expression of glucose transporter 5 (GLUT5), ketohexokinase (KHK)-A and KHK-C in miR-155 and miR-155 CFs under normoxia or hypoxia. A microarray analysis of circRNAs was performed to identify circHIF1α. Then CoIP, RIP and mass spectrometry analysis were performed and identified SKIV2L2 (MTR4) and transformer 2 alpha (TRA2A), a member of the transformer 2 homolog family. pAd-SKIV2L2 was administrated after coronary artery ligation to investigate whether SKIV2L2 can provide a protective effect on the infarcted heart.
When both miR-155 and miR-155 CFs were exposed to hypoxia for 24 h, these two cells exhibited an increased glycolysis and decreased glycogen synthesis, and the expression of KHK-A and KHK-C, the central fructose-metabolizing enzyme, was upregulated. Mechanistically, miR-155 deletion in CFs enhanced SKIV2L2 expression and its interaction with TRA2A, which suppresses the alternative splicing of HIF1α pre-mRNA to form circHIF1α, and then decreased circHIF1α contributed to the activation of fructose metabolism through increasing the production of the KHK-C isoform. Finally, exogenous delivery of SKIV2L2 reduced myocardial damage in the infarcted heart.
In this study, we demonstrated that miR-155 deletion facilitates the activation of fructose metabolism in hypoxic CFs through regulating alternative splicing of HIF1α pre-mRNA and thus circHIF1ɑ formation.
缺氧诱导因子 (HIF)1α 在缺氧条件下被激活并诱导糖酵解转变，然而，人们对缺氧诱导的心脏损伤中 HIF1α 激活的果糖分解作用关注甚少。
在这项研究中，我们旨在探讨 miR-155 介导的缺氧心肌成纤维细胞 (CFs)中果糖代谢的分子机制。
免疫染色、Western blot 和实时定量逆转录 PCR (qRT-PCR) 用于检测葡萄糖转运蛋白 5 (GLUT5)、酮己糖激酶 (KHK)-A 和 KHK-C 在 miR-155 和 miR-155 CFs 在常氧或缺氧下的表达。进行环状 RNA 的微阵列分析以鉴定环状 HIF1α。然后进行 CoIP、RIP 和质谱分析，鉴定 SKIV2L2（MTR4）和转化器 2 阿尔法 (TRA2A)，一种转化器 2 同源家族成员。在冠状动脉结扎后给予 pAd-SKIV2L2 以研究 SKIV2L2 是否可以对梗死心脏提供保护作用。
当 miR-155 和 miR-155 CFs 暴露于缺氧 24 小时时，这两种细胞表现出增强的糖酵解和减少的糖原合成，并且中央果糖代谢酶 KHK-A 和 KHK-C 的表达上调。机制上，CFs 中 miR-155 的缺失增强了 SKIV2L2 的表达及其与 TRA2A 的相互作用，从而抑制 HIF1α 前体 mRNA 的选择性剪接形成环状 HIF1α，然后减少环状 HIF1α 通过增加 KHK-C 同工型的产生促进果糖代谢的激活。最后，外源性递送 SKIV2L2 减少了梗死心脏的心肌损伤。
在这项研究中，我们证明 miR-155 的缺失通过调节 HIF1α 前体 mRNA 的选择性剪接和因此环状 HIF1ɑ 的形成促进缺氧 CFs 中果糖代谢的激活。
