Salubrinal通过活化eIF2α信号延缓细胞衰老的研究

Senescence is associated with a wide range of pathologies such as cancers, diabetes and cardiovascular disease. To delay onset of these disorders, one possible approach is to develop anti-aging agents that attenuate cellular senescence. Salubrinal, a selective inhibitor of eIF2alpha dephosphorylation, can increase the activation of eIF2alpha and cause translational suppression. Our previous findings indicated eIF2alpha activity may be involved the progress of senescence, while translational suppression is known to have anti-aging effects. Furthermore, we found NF-kB activity induced by TNF-alpha can be inhibited by salubrinal, while NF-kB also plays an important role in the process of senescence, especially in senescence associated secretory phenotype (SASP). Based on these knowledge, we hypothesized that salubrinal may inhibit cellular senescence via activation of eIF2alpha pathway. Our preliminary data showed, the progress of cellular senescence were attenuated by treatment with salubrinal, both in the premature senescence triggered by genetoxic stress in NRK-52E cells and in the replicative senescence generated by continuously passage in WI-38 cells. In the current project, we will further confirm our findings using other senescence markers, and investigate the effects of salubrinal on p53-p21WAF1 and p16INK4a signaling, and try to find out the underlying mechanisms. In addtion, the effects of salubrinal on ROS generation and NK-kB activity during senescence will also be examined. Our research may contribute to find new approaches for anti-aging and for the prevention of age-related disorders.

小分子化合物salubrinal可抑制eIF2a去磷酸化而选择性增加eIF2a磷酸化水平。课题申请人既往研究中发现eIF2a信号可能调节细胞衰老；我们还发现salubrinal可以通过eIF2a抑制NF-κB活性，而NF-κB亦参与细胞衰老调节。因此我们提出"Salubrinal可能通过活化eIF2a信号延缓细胞衰老"的设想。预实验结果显示salubrinal明显延缓细胞衰老的形态学改变及其导致的SA-b-gal活性升高。以此为基础，本课题拟进一步研究salubrinal、eIF2a信号活化及细胞衰老的关系，以及salubrinal是否能够和如何影响细胞衰老的核心信号p53-p21WAF1及p16INK4a通路。我们还将探讨salubrinal对细胞衰老发生过程中氧化应激及NF-κB活性的影响。我们希望通过上述研究证实我们的科研假说，并提示干预和延缓细胞衰老的新思路和新途径。

小分子化合物salubrinal可抑制eIF2α去磷酸化而选择性增加eIF2α磷酸化水平。在既往研究中发现eIF2α信号可能参与调节细胞衰老以及salubrinal可以抑制NF-κB活性的基础上，结合国外有关研究成果，我们提出“Salubrinal可能通过活化eIF2α信号延缓细胞衰老”的设想。在本课题的支持下，我们针对这项假说进行了下列实验内容: 1) 证实salubrinal通过活化eIF2α信号延缓细胞衰老; 2) 阐明salubrinal延缓细胞衰老的部分机制，例如该化合物对细胞衰老核心分子p21WAF1/CIP1及p16INK4a的影响及作用途径，对氧化应激和NF-κB的影响等；3)根据salubrinal改善etoposide引起的氧化应激的实验结果，本课题进行了部分拓展性的研究，探讨了线粒体功能障碍在salubrinal改善氧化应激中的作用以及自噬在细胞衰老中的作用。研究结果表明:Salubrinal改善Etoposide诱导的NRK-52E细胞衰老形态学改变，同时抑制p53–p21WAF1/CIP1 和p16INK4a 信号通路，进一步研究表明eIF2α磷酸化在salubrinal延缓细胞衰老中发挥了关键性作用。eIF2α信号通路是内质网应激(ER Stress)三条信号通路之一，但激活ER stress未能延缓Etoposide诱导的细胞衰老，反而诱导衰老细胞发生凋亡。另外，我们还发现1)Salubrinal主要通过抗氧化应激延缓细胞衰老，2)Etoposide刺激后NRK-52E细胞诱导自噬发生，而抑制自噬后诱导衰老细胞凋亡。本课题的研究数据提示干预和延缓细胞衰老的新思路和新途径。