KRIT1 功能丧失会导致慢性 Nrf2 介导的适应性稳态,使细胞对氧化应激敏感:对脑静脉畸形病的影响。
KRIT1 loss-of-function induces a chronic Nrf2-mediated adaptive homeostasis that sensitizes cells to oxidative stress: Implication for Cerebral Cavernous Malformation disease.
机构信息
Department of Experimental Medicine, University of Perugia, Italy.
Department of Clinical and Biological Sciences, University of Torino, Regione Gonzole 10, Orbassano, 10043 Torino, Italy.
出版信息
Free Radic Biol Med. 2018 Feb 1;115:202-218. doi: 10.1016/j.freeradbiomed.2017.11.014. Epub 2017 Nov 21.
KRIT1 (CCM1) is a disease gene responsible for Cerebral Cavernous Malformations (CCM), a major cerebrovascular disease of proven genetic origin affecting 0.3-0.5% of the population. Previously, we demonstrated that KRIT1 loss-of-function is associated with altered redox homeostasis and abnormal activation of the redox-sensitive transcription factor c-Jun, which collectively result in pro-oxidative, pro-inflammatory and pro-angiogenic effects, suggesting a novel pathogenic mechanism for CCM disease and raising the possibility that KRIT1 loss-of-function exerts pleiotropic effects on multiple redox-sensitive mechanisms. To address this possibility, we investigated major redox-sensitive pathways and enzymatic systems that play critical roles in fundamental cytoprotective mechanisms of adaptive responses to oxidative stress, including the master Nrf2 antioxidant defense pathway and its downstream target Glyoxalase 1 (Glo1), a pivotal stress-responsive defense enzyme involved in cellular protection against glycative and oxidative stress through the metabolism of methylglyoxal (MG). This is a potent post-translational protein modifier that may either contribute to increased oxidative molecular damage and cellular susceptibility to apoptosis, or enhance the activity of major apoptosis-protective proteins, including heat shock proteins (Hsps), promoting cell survival. Experimental outcomes showed that KRIT1 loss-of-function induces a redox-sensitive sustained upregulation of Nrf2 and Glo1, and a drop in intracellular levels of MG-modified Hsp70 and Hsp27 proteins, leading to a chronic adaptive redox homeostasis that counteracts intrinsic oxidative stress but increases susceptibility to oxidative DNA damage and apoptosis, sensitizing cells to further oxidative challenges. While supporting and extending the pleiotropic functions of KRIT1, these findings shed new light on the mechanistic relationship between KRIT1 loss-of-function and enhanced cell predisposition to oxidative damage, thus providing valuable new insights into CCM pathogenesis and novel options for the development of preventive and therapeutic strategies.
KRIT1(CCM1)是一种疾病基因,负责脑动静脉畸形(CCM),这是一种已被证实具有遗传起源的主要脑血管疾病,影响人群的 0.3-0.5%。以前,我们证明 KRIT1 功能丧失与氧化还原稳态的改变和氧化还原敏感转录因子 c-Jun 的异常激活有关,这共同导致了促氧化、促炎和促血管生成作用,为 CCM 疾病提供了新的发病机制,并提出了 KRIT1 功能丧失对多种氧化还原敏感机制产生多效性影响的可能性。为了解决这个问题,我们研究了在氧化应激适应性反应的基本细胞保护机制中发挥关键作用的主要氧化还原敏感途径和酶系统,包括主 Nrf2 抗氧化防御途径及其下游靶标 Glyoxalase 1(Glo1),这是一种关键的应激反应防御酶,通过甲基乙二醛(MG)的代谢参与细胞对糖基化和氧化应激的保护。这是一种有效的翻译后蛋白修饰物,它可能导致氧化分子损伤增加和细胞对细胞凋亡的敏感性增加,或者增强主要凋亡保护蛋白的活性,包括热休克蛋白(Hsps),促进细胞存活。实验结果表明,KRIT1 功能丧失会引起 Nrf2 和 Glo1 的氧化还原敏感持续上调,以及细胞内 MG 修饰的 Hsp70 和 Hsp27 蛋白水平下降,导致慢性适应性氧化还原平衡,对抗内在氧化应激,但增加对氧化 DNA 损伤和细胞凋亡的敏感性,使细胞对进一步的氧化应激更敏感。这些发现支持并扩展了 KRIT1 的多效性功能,为 KRIT1 功能丧失与增强细胞对氧化损伤的易感性之间的机制关系提供了新的见解,为 CCM 发病机制提供了有价值的新见解,并为预防和治疗策略的发展提供了新的选择。