SIRT1 in the cardiomyocyte counteracts doxorubicin-induced cardiotoxicity via regulating histone H2AX
SIRT1 in the cardiomyocyte counteracts doxorubicin-induced cardiotoxicity via regulating histone H2AX
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DOI：
10.1093/cvr/cvac026
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发表时间：
2022-03-08
影响因子：
10.8
通讯作者：
Horio, Yoshiyuki
中科院分区：
文献类型：
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作者：
Kuno, Atsushi;Hosoda, Ryusuke;Horio, Yoshiyuki
目的 阿霉素的心脏毒性预示着患者预后较差。受损 DNA 的积累与阿霉素诱导的心脏毒性有关。 SIRT1 是一种 NAD(+) 依赖性组蛋白/蛋白质脱乙酰酶，通过使靶蛋白脱乙酰化来保护细胞。我们研究了 SIRT1 是否通过介导组蛋白 H2AX 的 Ser139 磷酸化（DNA 损伤反应的关键信号）来抵消阿霉素诱导的心脏毒性。 方法和结果 将阿霉素（每周 5 mg/kg，x4）给予具有完整 SIRT1 的小鼠 (Sirt1(f/f)) 和心肌细胞中缺乏 SIRT1 活性的小鼠 (Sirt1(f/f)；MHCcre/+)。 Sirt1(f/f)；MHCcre/+ 中阿霉素治疗后左心室缩短分数和射血分数的降低比 Sirt1(f/f) 中更严重。阿霉素治疗后，Sirt1(f/f)；MHCcre/+ 中 B 型利尿钠肽的心肌表达水平比 Sirt1(f/f) 中高 2.5 倍。 Sirt1f(/ f);MHCcre/+ 在多柔比星治疗后，心脏中显示出更大的纤维化区域和更高的硝基酪氨酸水平。尽管通过 TUNEL 染色评估的多柔比星诱导的 DNA 损伤在 Sirt1(f/f);MHCcre/+ 中增强，但来自 Sirt1(f/f);MHCcre/+ 的心肌显示多柔比星处理减弱了 H2AX Ser139 磷酸化。在 H9c2 心肌细胞中，SIRT1 敲低减弱了 H2AX Ser139 磷酸化，增加了 DNA 损伤，并增强了多柔比星处理下的 caspase-3 激活。免疫染色显示，Sirt1(f/)f；MHCcre/+ 心脏中 H2AX Lys5 的乙酰化水平较高。在 H9c2 细胞中，乙酰基-Lys5-H2AX 水平因 SIRT1 敲低而增加，并因 SIRT1 过表达而降低。与野生型 H2AX 相比，通过将 Lys5 替换为 Gln (K5Q)，模拟乙酰化赖氨酸，突变型 H2AX 中响应阿霉素处理的 Ser139 磷酸化减弱。 K5Q-H2AX 和 S139A-H2AX（在 Ser139 位点不能磷酸化）的表达增强了阿霉素诱导的 caspase-3 激活。用白藜芦醇（SIRT1 激活剂）治疗小鼠，可减轻阿霉素诱导的心脏功能障碍，这与乙酰基-Lys5-H2AX 水平的降低和磷酸-Ser139-H2AX 水平的保留有关。结论这些发现表明，SIRT1 通过心肌细胞中的脱乙酰化介导 H2AX 磷酸化，从而抵消阿霉素诱导的心脏毒性。[图表]。
Aims Cardiotoxicity by doxorubicin predicts worse prognosis of patients. Accumulation of damaged DNA has been implicated in doxorubicin-induced cardiotoxicity. SIRT1, an NAD(+)-dependent histone/protein deacetylase, protects cells by deacetylating target proteins. We investigated whether SIRT1 counteracts doxorubicin-induced cardiotoxicity by mediating Ser139 phosphorylation of histone H2AX, a critical signal of the DNA damage response.Methods and results Doxorubicin (5 mg/kg per week, x4) was administered to mice with intact SIRT1 (Sirt1(f/f)) and mice that lack SIRT1 activity in cardiomyocytes (Sirt1(f/f);MHCcre/+). Reductions in left ventricular fractional shortening and ejection fraction by doxorubicin treatment were more severe in Sirt1(f/f);MHCcre/+ than in Sirt1(f/f). Myocardial expression level of type-B natriuretic peptide was 2.5-fold higher in Sirt1(f/f);MHCcre/+ than in Sirt1(f/f) after doxorubicin treatment. Sirt1f(/ f);MHCcre/+ showed larger fibrotic areas and higher nitrotyrosine levels in the heart after doxorubicin treatment. Although doxorubicin-induced DNA damage evaluated by TUNEL staining was enhanced in Sirt1(f/f);MHCcre/+, the myocardium from Sirt1(f/f);MHCcre/+ showed blunted Ser139 phosphorylation of H2AX by doxorubicin treatment. In H9c2 cardiomyocytes, SIRT1 knockdown attenuated Ser139 phosphorylation of H2AX, increased DNA damage, and enhanced caspase-3 activation under doxorubicin treatment. Immunostaining revealed that acetylation level of H2AX at Lys5 was higher in hearts from Sirt1(f/)f;MHCcre/+. In H9c2 cells, acetyl-Lys5-H2AX level was increased by SIRT1 knockdown and reduced by SIRT1 overexpression. Ser139 phosphorylation in response to doxorubicin treatment was blunted in a mutant H2AX with substitution of Lys5 to Gln (K5Q) that mimics acetylated lysine compared with that in wild-type H2AX. Expression of K5Q-H2AX as well as S139A-H2AX, which cannot be phosphorylated at Ser139, augmented doxorubicin-induced caspase-3 activation. Treatment of mice with resveratrol, a SIRT1 activator, attenuated doxorubicin-induced cardiac dysfunction, which was associated with a reduction in acetyl-Lys5-H2AX level and a preserved phospho-Ser139-H2AX level.Conclusion These findings suggest that SIRT1 counteracts doxorubicin-induced cardiotoxicity by mediating H2AX phosphorylation through its deacetylation in cardiomyocytes.[GRAPHICS].