Mengnan Li, Yingying Hao, Xinyue Song, Huiyu Liu, Chi Zhang, Jiaqi Zhang, Hanliang Sun, Xiaodong Zheng, Lixin Zhang, Hang Yu, Cui Ma, Xijuan Zhao, Daling Zhu
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引用次数: 0
Abstract
Background: Ferroptosis has been implicated in pulmonary hypertension (PH), and chromatin-associated RNAs are increasingly recognized as key regulators of this process. However, the detailed mechanism remains unexplored.
Methods: Bioinformatics, Sanger sequencing, and RNase R digestion were used to identify the upregulation of ca-circSCN8A. Functional gain and loss assays were used to unveil the role of ca-circSCN8A in hypoxic redox-dependent ferroptosis in human pulmonary arterial smooth muscle cells and a PH mice model. Interaction between ca-circSCN8A and FUS was detected via RNA immunoprecipitation and pull-down assays. Fluorescence recovery after photobleaching, ChIRP-qPCR, malondialdehyde, reduced glutathione, and glutathione were conducted to explore the potential molecular mechanism.
Results: ca-circSCN8A was identified and confirmed to be upregulated in PH. Its overexpression promoted hypoxia-induced ferroptosis in human pulmonary arterial smooth muscle cells. Under hypoxic conditions, ca-circSCN8A recruited EP300 to facilitate the lactylation of FUS, triggering the formation of a ca-circSCN8A/FUS/EP300 complex via liquid-liquid phase separation. Liquid-liquid phase separation maintained the stability of the R-loop formed by ca-circSCN8A and ferroptosis-related gene SLC7A11 (solute carrier family 7 member 11) promoter that inhibits its transcription, further result in the disruption of the redox homeostasis and causing ferroptosis in human pulmonary arterial smooth muscle cells.
Conclusions: ca-circSCN8A recruits EP300 to promote the lactylation of FUS, thereby driving liquid-liquid phase separation-mediated complex formation with FUS and EP300. This process enables ca-circSCN8A to form an R-loop with the nonhost SLC7A11 promoter, contributing to the regulation of hypoxia-induced ferroptosis in human pulmonary arterial smooth muscle cells. This study provides the first evidence that circRNAs can form R-loops with nonhost genes in a liquid-liquid phase separation-dependent manner. Our findings highlight ca-circSCN8A as a crucial regulator of ferroptosis in hypoxic PH and a potential therapeutic target for PH.
期刊介绍:
Hypertension presents top-tier articles on high blood pressure in each monthly release. These articles delve into basic science, clinical treatment, and prevention of hypertension and associated cardiovascular, metabolic, and renal conditions. Renowned for their lasting significance, these papers contribute to advancing our understanding and management of hypertension-related issues.