Aims Declining cellular functional capacity resulting from stress or aging is a primary contributor to impairment of myocardial performance. Molecular pathway regulation of biological processes in cardiac interstitial cells (CICs) is pivotal in stress and aging responses. Altered localization of the RNA binding protein Lin28A has been reported in response to environmental stress, but the role of Lin28A in response to stress in CICs has not been explored. Surface Lin28A redistribution is indicative of stress response in CIC associated with aging and senescence. Methods and Results Localization of Lin28A was assessed by multiple experimental analyses and treatment conditions and correlated to oxidative stress, senescence, and ploidy in adult murine CICs. Surface Lin28A expression is present on 5% of fresh CICs and maintained through passage 2, increasing to 21% in hyperoxic conditions but lowered to 14% in physiologic normoxia. Surface Lin28A is coincident with elevated senescence marker p16 and beta-galactosidase (β-gal) expression in CICs expanded in hyperoxia, and also increases with polyploidization and binucleation of CICs regardless of oxygen culture. Transcriptional profiling of CICs using single cell RNASeq reveals upregulation of pathways associated with oxidative stress in CICs exhibiting surface Lin28A. Induction of surface Lin28A by oxidative stress is blunted by treatment of cells with the antioxidant Trolox in a dose-dependent manner, with 300uM Trolox exposure maintaining characteristics of freshly isolated CICs possessing low expression of surface Lin28A and β-gal with predominantly diploid content. Conclusion Surface Lin28A is a marker of environmental oxidative stress in CICs and antioxidant treatment antagonizes this phenotype. The biological significance of Lin28 surface expression and consequences for myocardial responses may provide important insights regarding mitigation of cardiac stress and aging. Translational Perspective Cellular phenotypic changes occurring in response to oxidative stress provides critical insights into biological processes of pathological injury and aging. Surface Lin28A is novel surface marker of oxidative stress conditions that cause DNA damage and cellular senescence. Accumulation of surface Lin28A was inhibited by antioxidant treatment with lowered indices of cellular stress and senescence, revealing the potential of surface Lin28A as a diagnostic stress marker. Furthermore, therapeutic strategies targeted toward surface Lin28 expression set the stage for next generation senolytics to remove stressed or senescent cells and promote recovery from tissue injury or aging.

中文翻译：

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表面 Lin28A 表达与细胞应激一致，与衰老指标相似

目标 压力或衰老导致的细胞功能下降是心肌性能受损的主要原因。心脏间质细胞（CIC）生物过程的分子途径调节对于应激和衰老反应至关重要。据报道，RNA 结合蛋白 Lin28A 的定位发生改变以应对环境压力，但 Lin28A 在 CIC 中应对压力的作用尚未被探索。表面 Lin28A 重新分布表明 CIC 中与衰老和衰老相关的应激反应。方法和结果 Lin28A 的定位通过多项实验分析和治疗条件进行评估，并与成年小鼠 CIC 中的氧化应激、衰老和倍性相关。表面 Lin28A 表达存在于 5% 的新鲜 CIC 上，并维持到第 2 代，在高氧条件下增加至 21%，但在生理含氧量正常时降低至 14%。表面 Lin28A 与高氧条件下扩增的 CIC 中衰老标记物 p16 和 β-半乳糖苷酶 (β-gal) 表达升高一致，并且无论氧培养如何，也随着 CIC 的多倍化和双核而增加。使用单细胞 RNASeq 对 CIC 进行转录分析，揭示了表面具有 Lin28A 的 CIC 中与氧化应激相关的通路的上调。通过用抗氧化剂 Trolox 以剂量依赖性方式处理细胞，可以减弱氧化应激对表面 Lin28A 的诱导，300uM Trolox 暴露保持了新鲜分离的 CIC 的特征，其表面 Lin28A 和 β-gal 低表达，主要是二倍体含量。结论表面Lin28A是CIC中环境氧化应激的标志物，抗氧化治疗可以拮抗这种表型。Lin28 表面表达的生物学意义及其对心肌反应的影响可能为减轻心脏应激和衰老提供重要见解。转化视角响应氧化应激而发生的细胞表型变化为病理损伤和衰老的生物过程提供了重要的见解。Surface Lin28A 是导致 DNA 损伤和细胞衰老的氧化应激条件的新型表面标记。抗氧化处理可抑制表面 Lin28A 的积累，降低细胞应激和衰老指数，揭示表面 Lin28A 作为诊断应激标记物的潜力。此外，针对表面 Lin28 表达的治疗策略为下一代 senolytics 奠定了基础，以消除应激或衰老细胞并促进组织损伤或衰老的恢复。