Department of Dermatology and Venereology, Jiangsu Provincial People's Hospital, First Affiliated Hospital of Nanjing Medical University, 210029, China.
Department of Dermatology and Venereology, Jiangsu Provincial People's Hospital, First Affiliated Hospital of Nanjing Medical University, 210029, China.
Life Sci. 2018 Nov 1;212:213-224. doi: 10.1016/j.lfs.2018.10.003. Epub 2018 Oct 4.
Stem cell transplantation is a promising tool to treat burn injuries. However, the inflammatory microenvironment in damaged skin limits the efficiency of stem cell-based therapy via poorly understood mechanisms. The aim of our study is to explore the contribution and mechanism of Sirtuin-1 (Sirt1) in TNFα-mediated inflammatory stress in hair follicle stem cells (HFSCs).
Cellular viability was determined using the MTT assay, TUNEL staining, western blot analysis and LDH release assay. Adenovirus-loaded Sirt1 was transduced into HFSCs to overexpress Sirt1 in the presence of TNFα. Mitochondrial function was determined using JC-1 staining, mitochondrial ROS staining, immunofluorescence staining and western blotting.
Sirt1 was downregulated in response to the TNFα treatment. Additionally, TNFα stress reduced the viability, mobility and proliferation of HFSCs, and these effects were reversed by the overexpression of Sirt1. At the molecular level, Sirt1 overexpression attenuated TNFα-mediated mitochondrial damage, as evidenced by increased mitochondrial energy metabolism, decreased mitochondrial ROS generation, stabilized mitochondrial potential and blockage of the mitochondrial apoptotic pathway. Furthermore, Sirt1 modulated mitochondrial homeostasis by activating the MAPK-ERK-Mfn2 axis; inhibition of this pathway abrogated the protective effects of Sirt1 on HFSC survival, migration and proliferation.
Based on our results, the inflammatory stress-mediated HFSC injury may be associated with a decrease in Sirt1 expression and subsequent mitochondrial dysfunction. Accordingly, strategies designed to enhance Sirt1 expression would be an effective approach to enhance the survival of HFSCs in the inflammatory microenvironment.
干细胞移植是治疗烧伤的一种很有前途的工具。然而，受损皮肤中的炎症微环境通过尚未被充分了解的机制限制了基于干细胞的治疗效率。我们的研究目的是探索 Sirtuin-1（Sirt1）在 TNFα 介导的毛囊干细胞（HFSCs）炎症应激中的作用及其机制。
使用 MTT 检测、TUNEL 染色、western blot 分析和 LDH 释放检测来确定细胞活力。在 TNFα 存在的情况下，将负载 Sirt1 的腺病毒转导到 HFSCs 中以过表达 Sirt1。使用 JC-1 染色、线粒体 ROS 染色、免疫荧光染色和 western blot 来确定线粒体功能。
Sirt1 对 TNFα 处理呈下调表达。此外，TNFα 应激降低了 HFSCs 的活力、迁移和增殖能力，而过表达 Sirt1 可逆转这些作用。在分子水平上，Sirt1 过表达减轻了 TNFα 介导的线粒体损伤，这表现在增加线粒体能量代谢、减少线粒体 ROS 生成、稳定线粒体电位和阻断线粒体凋亡途径。此外，Sirt1 通过激活 MAPK-ERK-Mfn2 轴来调节线粒体稳态；抑制该途径可消除 Sirt1 对 HFSC 存活、迁移和增殖的保护作用。
根据我们的结果，炎症应激介导的 HFSC 损伤可能与 Sirt1 表达的降低以及随后的线粒体功能障碍有关。因此，设计增强 Sirt1 表达的策略可能是增强 HFSCs 在炎症微环境中存活的有效方法。
