Proline metabolic reprogramming modulates cardiac remodeling induced by pressure overload in the heart

Metabolic reprogramming is critical in the onset of pressure overload-induced cardiac remodeling. Our study reveals that proline dehydrogenase (PRODH), the key enzyme in proline metabolism, reprograms cardiomyocyte metabolism to protect against cardiac remodeling. We induced cardiac remodeling using transverse aortic constriction (TAC) in both cardiac-specific PRODH knockout and overexpression mice. Our results indicate that PRODH expression is suppressed post-TAC. Cardiac-specific PRODH knockout mice exhibited worsened cardiac dysfunction, while mice with PRODH overexpression demonstrated a protective effect. Additionally, we simulated cardiomyocyte hypertrophy in vitro using neonatal rat ventricular myocytes treated with phenylephrine. Through RNA sequencing, metabolomics, and metabolic flux analysis, we elucidated that PRODH overexpression in cardiomyocytes redirects proline catabolism to replenish tricarboxylic acid (TCA) cycle intermediates, enhance energy production, and restore glutathione redox balance. In summary, our findings suggest PRODH as a modulator of cardiac bioenergetics and redox homeostasis duing cardiac remodeling induced by pressure overload. This highlights the potential of PRODH as a therapeutic target for cardiac remodeling. To investigate the role of PRODH in the regulation of pressure overload-induced cardiac remodeling, cardiac-specific overexpression of PRODH was achieved through AAV9-mediated delivery system. Two types of viruses, AAV9-Vector and AAV9-PRODH, were injected into mice, and transverse aortic constriction (TAC) surgery was performed. Four weeks post-surgery, cardiac tissues were collected for the isolation of adult mice cardiac myocytes, followed by the RNA-seq analysis. The primary aim of our study was to compare the changes of adult mice cardiac myocytes between the TAC group and the Sham group in AAV9-Vector mice, as well as to assess the transcriptomic differences between the AAV9-Vector and AAV9-PRODH groups in mice following TAC surgery.

代谢重编程在压力负荷诱导的心脏重构发病过程中至关重要。本研究揭示，脯氨酸代谢的关键酶——脯氨酸脱氢酶（proline dehydrogenase, PRODH）可通过重编程心肌细胞代谢，发挥对抗心脏重构的保护作用。我们分别在心肌特异性PRODH敲除与过表达小鼠模型中，通过主动脉弓缩窄术（transverse aortic constriction, TAC）构建心脏重构模型，实验结果显示TAC术后PRODH的表达受到抑制。心肌特异性PRODH敲除小鼠的心脏功能障碍程度加重，而PRODH过表达小鼠则表现出心脏保护效应。此外，我们采用苯肾上腺素处理新生大鼠心室肌细胞，体外模拟心肌肥厚模型。通过RNA测序（RNA sequencing）、代谢组学（metabolomics）与代谢流分析（metabolic flux analysis），我们阐明了心肌细胞中PRODH过表达可重塑脯氨酸分解代谢途径，补充三羧酸（tricarboxylic acid, TCA）循环中间产物、提升能量生成并恢复谷胱甘肽氧化还原稳态。综上，本研究结果表明PRODH可作为压力负荷诱导心脏重构过程中心脏生物能与氧化还原稳态的调控因子，提示PRODH有望成为心脏重构的治疗靶点。为进一步探究PRODH在压力负荷诱导心脏重构调控中的作用，我们通过腺相关病毒9型（AAV9）介导的递送系统实现小鼠心肌特异性PRODH过表达。将AAV9-空载体与AAV9-PRODH两种病毒分别注射入小鼠体内，随后实施主动脉弓缩窄术（TAC）。术后4周，采集心脏组织以分离成年小鼠心肌细胞并进行RNA测序分析。本研究的主要目的为对比AAV9-空载体小鼠中TAC组与假手术（Sham）组成年小鼠心肌细胞的转录组变化，同时评估TAC术后AAV9-空载体组与AAV9-PRODH组小鼠的转录组差异。