Tousled kinase activator, gallic acid, promotes homologous recombinational repair and suppresses radiation cytotoxicity in salivary gland cells.
Tousled kinase activator, gallic acid, promotes homologous recombinational repair and suppresses radiation cytotoxicity in salivary gland cells.
复制标题
混合激酶激活剂食道酸，促进同源重组修复并抑制唾液腺细胞中的辐射细胞毒性。
DOI：
10.1016/j.freeradbiomed.2015.12.029
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发表时间：
2016-04
影响因子：
7.4
通讯作者：
Sunavala-Dossabhoy G
中科院分区：
文献类型：
--
作者：
Timiri Shanmugam PS;Nair RP;De Benedetti A;Caldito G;Abreo F;Sunavala-Dossabhoy G
唾液腺的意外或医疗辐射照射会严重影响口腔健康。以前的研究表明，Tousled样激酶1（TLK 1）及其替代起始变体TLK 1B在细胞抗遗传毒性应激的存活中的重要性。通过对天然化合物的高通量文库筛选，酚类植物化学物质没食子酸（GA）被鉴定为TLK 1/1B的调节剂。这种小分子具有抗氧化和清除自由基的特性，但在这项研究中，我们报告说，在体外，它促进人类唾液腺泡细胞，NS-SV-AC，通过修复电离辐射损伤的生存。与未处理的对照相比，用GA处理的辐照细胞显示出改善的克隆形成存活。而且，通过碱性单细胞凝胶电泳和γ-H2 AX焦点免疫荧光分析DNA修复动力学表明，药物处理的细胞中DNA断裂的快速解决。DR-GFP转基因修复的研究表明GA促进同源重组修复以建立功能性GFP基因。相反，TLK 1的失活或其shRNA敲低抑制了NS-SV-AC中辐射诱导的DNA尾的解析，以及DRGFP细胞中的同源性定向修复。与我们在培养中的结果一致，暴露于分次辐射后用GA处理的动物与盐水处理的动物相比显示出更好的唾液功能保存。我们的研究结果表明，GA介导的TLK 1活性的瞬时调节促进DNA修复和抑制唾液腺细胞的辐射细胞毒性。
Accidental or medical radiation exposure of the salivary glands can gravely impact oral health. Previous studies have shown the importance of Tousled-like kinase 1 (TLK1) and its alternate start variant TLK1B in cell survival against genotoxic stresses. Through a high-throughput library screening of natural compounds, the phenolic phytochemical, gallic acid (GA), was identified as a modulator of TLK1/1B. This small molecule possesses anti-oxidant and free radical scavenging properties, but in this study, we report that in vitro it promotes survival of human salivary acinar cells, NS-SV-AC, through repair of ionizing radiation damage. Irradiated cells treated with GA show improved clonogenic survival compared to untreated controls. And, analyses of DNA repair kinetics by alkaline single-cell gel electrophoresis and γ-H2AX foci immunofluorescence indicate rapid resolution of DNA breaks in drug-treated cells. Study of DR-GFP transgene repair indicates GA facilitates homologous recombinational repair to establish a functional GFP gene. In contrast, inactivation of TLK1 or its shRNA knockdown suppressed resolution of radiation-induced DNA tails in NS-SV-AC, and homology directed repair in DRGFP cells. Consistent with our results in culture, animals treated with GA after exposure to fractionated radiation showed better preservation of salivary function compared to saline-treated animals. Our results suggest that GA-mediated transient modulation of TLK1 activity promotes DNA repair and suppresses radiation cytoxicity in salivary gland cells.