Kuppa Annapurna, Alzamrooni Afnan, Lopez Rachel, Suhan Tahra, Chaudhary Rajesh, Collins Nicole, Van den Bergh Fran, Abouleisa Riham, Wang Harrison, Mohamed Tamer, Satin Jonathan, Lyssiotis Costas, Beard Daniel A, Abdel-Latif Ahmed
bioRxiv. 2024 May 26:2024.05.22.595229. doi: 10.1101/2024.05.22.595229.
The adult mammalian heart has limited regenerative capacity following injury, leading to progressive heart failure and mortality. Recent studies have identified the spiny mouse ( ) as a unique model for mammalian cardiac isch3emic resilience, exhibiting enhanced recovery after myocardial infarction (MI) compared to commonly used laboratory mouse strains. However, the underlying cellular and molecular mechanisms behind this unique response remain poorly understood. In this study, we comprehensively characterized the metabolic characteristics of cardiomyocytes in compared to the non-regenerative . We utilized single-nucleus RNA sequencing (snRNA-seq) in sham-operated animals and 1, 3, and 7 days post-myocardial infarction to investigate cardiomyocytes' transcriptomic and metabolomic profiles in response to myocardial infarction. Complementary targeted metabolomics, stable isotope-resolved metabolomics, and functional mitochondrial assays were performed on heart tissues from both species to validate the transcriptomic findings and elucidate the metabolic adaptations in cardiomyocytes following ischemic injury. Transcriptomic analysis revealed that cardiomyocytes inherently upregulate genes associated with glycolysis, the pentose phosphate pathway, and glutathione metabolism while downregulating genes involved in oxidative phosphorylation (OXPHOS). These metabolic characteristics are linked to decreased reactive oxygen species (ROS) production and increased antioxidant capacity. Our targeted metabolomic studies in heart tissue corroborated these findings, showing a shift from fatty acid oxidation to glycolysis and ancillary biosynthetic pathways in at baseline with adaptive changes post-MI. Functional mitochondrial studies indicated a higher reliance on glycolysis in compared to , underscoring the unique metabolic phenotype of hearts. Stable isotope tracing experiments confirmed a shift in glucose utilization from oxidative phosphorylation in . In conclusion, our study identifies unique metabolic characteristics of cardiomyocytes that contribute to their enhanced ischemic resilience following myocardial infarction. These findings provide novel insights into the role of metabolism in regulating cardiac repair in adult mammals. Our work highlights the importance of inherent and adaptive metabolic flexibility in determining cardiomyocyte ischemic responses and establishes as a valuable model for studying cardiac ischemic resilience in adult mammals.
成年哺乳动物心脏在受伤后再生能力有限,会导致进行性心力衰竭和死亡。最近的研究已将刺毛鼠确定为哺乳动物心脏缺血恢复力的独特模型,与常用的实验室小鼠品系相比,其在心肌梗死(MI)后表现出更强的恢复能力。然而,这种独特反应背后的潜在细胞和分子机制仍知之甚少。在本研究中,我们全面表征了刺毛鼠与无再生能力的小鼠相比心肌细胞的代谢特征。我们在假手术动物以及心肌梗死后1天、3天和7天利用单核RNA测序(snRNA-seq)来研究心肌细胞对心肌梗死的转录组和代谢组谱。对两个物种的心脏组织进行了互补的靶向代谢组学、稳定同位素分辨代谢组学和线粒体功能分析,以验证转录组学发现并阐明缺血性损伤后心肌细胞的代谢适应性。转录组分析显示,刺毛鼠心肌细胞固有地上调与糖酵解、磷酸戊糖途径和谷胱甘肽代谢相关的基因,同时下调参与氧化磷酸化(OXPHOS)的基因。这些代谢特征与活性氧(ROS)产生减少和抗氧化能力增强有关。我们对心脏组织的靶向代谢组学研究证实了这些发现,表明在基线时刺毛鼠从脂肪酸氧化转变为糖酵解和辅助生物合成途径,心肌梗死后有适应性变化。线粒体功能研究表明,与无再生能力的小鼠相比,刺毛鼠对糖酵解的依赖性更高,突出了刺毛鼠心脏独特的代谢表型。稳定同位素示踪实验证实了刺毛鼠葡萄糖利用从氧化磷酸化的转变。总之,我们的研究确定了刺毛鼠心肌细胞的独特代谢特征,这些特征有助于其在心肌梗死后增强缺血恢复力。这些发现为代谢在调节成年哺乳动物心脏修复中的作用提供了新的见解。我们的工作强调了固有和适应性代谢灵活性在决定心肌细胞缺血反应中的重要性,并将刺毛鼠确立为研究成年哺乳动物心脏缺血恢复力的有价值模型。