Curcumin improves atrial fibrillation susceptibility by regulating tsRNA expression in aging mouse atrium. Curcumin improves atrial fibrillation susceptibility by regulating tsRNA expression in aging mouse atrium

Age is an independent risk factor for atrial fibrillation (AF), and curcumin can delay aging related disease through reducing oxidative stress and inflammation. However, its target in aging-related AF remains unclear. Transfer RNA-derived small RNA (tsRNA) is a novel short non-coding RNA (sncRNA), and exerts a potential regulatory function in aging. This study was to explore the therapeutic targets of curcumin in atrium of aged mice by PANDORA-seq. Aged mice (18 month) were treated with curcumin (100mg/kg). Rapid transjugular atrial pacing was performed to observe AF inducibility. SA-β-gal staining, ROS detection and qRT-PCR were used to assess the degree of aging and oxidative stress/inflammation levels. PANDORA-seq was performed to reveal the differentially expressed sncRNAs in the atrium of mice. The results showed that curcumin reduced the susceptibility AF of aged mice by improving aging-related atrial fibrosis. Compared to young mice (5 month) group, aged mice yielded 473 significantly altered tsRNA sequences, while 947 tsRNA sequences were significantly altered after treated with curcumin. Enrichment analysis revealed that the target genes were mainly related to DNA damage and protein modification. Compared with the 5mo group, the expression levels of mature-mt_tRNA-Val-TAC_CCA_end, mature-mt_tRNA-Glu-TTC_CCA_end, and mature-tRNA-Asp-GTC_CCA_end were up-regulated in the 18mo group, while the expression of mature-mt_tRNA-Thr-TGT_5_end was down-regulated. This trend was reversed in the 18mo+curcumin group. Increased cellular ROS levels, inflammation expression and senescence in aged mice atrium were improved by the down-regulation of mature-mt_tRNA-Val-TAC_CCA_end. In conclusion, our findings identified mature-mt_tRNA-Val-TAC_CCA_end participated in the mechanism of aging-related atrial fibrosis, providing new intervention target of aging-related AF. Overall design: The mice were randomly divided into three groups (n = 3) : 5-month-old (young), 18-month-old (old) and curcumin treated 18-month-old mice. curcumin treated 18-month-old mice were received 100mg/kg curcumin daily in the non-fat skim milk, starting from the age of 12 months until 18 months.

年龄是心房颤动（atrial fibrillation, AF）的独立危险因素，姜黄素可通过减轻氧化应激与炎症反应延缓衰老相关疾病，但目前其在衰老相关性房颤中的作用靶点仍不明确。转运RNA衍生小RNA（transfer RNA-derived small RNA, tsRNA）是一类新型短链非编码RNA（short non-coding RNA, sncRNA），在衰老进程中发挥潜在调控功能。本研究旨在通过PANDORA-seq技术，探究姜黄素在衰老小鼠心房组织中的治疗靶点。选取18月龄衰老小鼠，以100mg/kg剂量给予姜黄素干预。通过颈静脉快速心房起搏观察房颤诱发情况。采用SA-β-gal染色、活性氧（reactive oxygen species, ROS）检测及实时荧光定量PCR（qRT-PCR），分别评估小鼠心房的衰老程度、氧化应激与炎症水平。利用PANDORA-seq技术分析小鼠心房组织中差异表达的非编码RNA。研究结果显示，姜黄素可通过改善衰老相关心房纤维化，降低衰老小鼠的房颤易感性。与5月龄年轻小鼠组相比，18月龄衰老小鼠中共存在473个显著差异表达的tsRNA序列；姜黄素干预后，又有947个tsRNA序列出现显著表达改变。富集分析结果表明，这些差异tsRNA的靶基因主要参与DNA损伤与蛋白质修饰过程。相较于5月龄组，18月龄组小鼠心房中成熟线粒体转运RNA-Val-TAC_CCA_end、成熟线粒体转运RNA-Glu-TTC_CCA_end及成熟转运RNA-Asp-GTC_CCA_end的表达水平均显著上调，而成熟线粒体转运RNA-Thr-TGT_5_end的表达则显著下调。该表达趋势在18月龄+姜黄素干预组中发生完全逆转。下调成熟线粒体转运RNA-Val-TAC_CCA_end，可改善衰老小鼠心房内升高的ROS水平、炎症因子表达及细胞衰老状态。综上，本研究证实成熟线粒体转运RNA-Val-TAC_CCA_end参与了衰老相关心房纤维化的发病机制，为衰老相关性房颤提供了全新的干预靶点。整体实验设计：将小鼠随机分为3组（n=3）：5月龄（年轻组）、18月龄（衰老组）及姜黄素干预的18月龄小鼠组。姜黄素干预组小鼠自12月龄起，每日以脱脂乳为溶剂给予100mg/kg姜黄素，持续给药至18月龄。