Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai, China.
Theranostics. 2024 Sep 9;14(15):5793-5808. doi: 10.7150/thno.97767. eCollection 2024.
: Heart failure with preserved ejection fraction (HFpEF) is a predominant type of heart failure. Exploring new pathogenesis and identifying potential novel therapeutic targets for HFpEF is of paramount importance. : HFpEF mouse model was established by the "Multiple-hit" strategy, in that 18- to 22-month-old female C57B6/J mice fed with a high-fat diet were further challenged with chronic infusion of Angiotensin II. RNA sequencing analysis showed that USP7 was significantly increased in the heart of HFpEF mice. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis, in conjunction with co-immunoprecipitation (Co-IP) techniques, identified expression of SMAD3, the key molecule of endothelial-to-mesenchymal transition (EndMT), was also significantly elevated. USP7 endothelium-specific knockout mice was generated to investigate the involvement of USP7 in HFpEF. The biological significance of the interaction between USP7 and SMAD3 was further explored. : USP7 promotes EndMT and cardiac fibrosis by binding to SMAD3 directly via its UBL (Ubiquitin-like) domain and cysteine at position 223 of USP7, leading SMAD3 deubiquitination to maintain the stability of SMAD3 by removing the K63 ubiquitin chain and preventing the degradation of SMAD3 by proteasomal process. USP7 also promotes SMAD3 phosphorylation and nuclear translocation, thereby aggravating EndMT and cardiac fibrosis. Endothelium-specific USP7 knockout led to improvement of HFpEF phenotypes and reduction of cardiac fibrosis. Overexpression of SMAD3 in endothelium-specific knockout HFpEF mice reversed the protective effects of USP7 knockout in this HFpEF mouse model. Our results indicated that USP7 is one of the key pathogenic molecules of HFpEF, and knocking out USP7 could attenuate HFpEF injury by promoting the degradation of SMAD3. USP7 and SMAD3 inhibition might be potential therapeutic options for HFpEF.
心力衰竭伴射血分数保留（HFpEF）是心力衰竭的主要类型。探索新的发病机制并确定 HFpEF 的潜在新治疗靶点至关重要。
我们通过“多击”策略建立了 HFpEF 小鼠模型，即给 18-22 月龄的 C57B6/J 雌性小鼠喂食高脂肪饮食，然后用血管紧张素 II 进行慢性输注。RNA 测序分析表明，USP7 在 HFpEF 小鼠心脏中显著增加。液相色谱串联质谱（LC-MS/MS）分析结合免疫共沉淀（Co-IP）技术表明，内皮向间质转化（EndMT）的关键分子 SMAD3 的表达也显著升高。我们生成了 USP7 内皮细胞特异性敲除小鼠以研究 USP7 在 HFpEF 中的参与。进一步探讨了 USP7 与 SMAD3 之间相互作用的生物学意义。
USP7 通过其 UBL（泛素样）结构域和 USP7 位置 223 的半胱氨酸直接与 SMAD3 结合，促进 EndMT 和心脏纤维化，导致 SMAD3 去泛素化，通过去除 K63 泛素链并防止 SMAD3 通过蛋白酶体过程降解，从而维持 SMAD3 的稳定性。USP7 还促进 SMAD3 磷酸化和核易位，从而加重 EndMT 和心脏纤维化。内皮细胞特异性 USP7 敲除导致 HFpEF 表型改善和心脏纤维化减少。内皮细胞特异性敲除 HFpEF 小鼠中 SMAD3 的过表达逆转了 USP7 敲除对该 HFpEF 小鼠模型的保护作用。
我们的结果表明，USP7 是 HFpEF 的关键致病分子之一，敲除 USP7 可通过促进 SMAD3 的降解来减轻 HFpEF 损伤。USP7 和 SMAD3 抑制可能是 HFpEF 的潜在治疗选择。
