Department of Translational and Discovery Research, IRBM S.p.A., Via Pontina Km 30,600, 00071, Pomezia, Roma, Italy.
Department of Drug Discovery, IRBM S.p.A., Via Pontina Km 30, 600 - 00071, Pomezia, Roma, Italy.
Free Radic Biol Med. 2021 Jan;162:243-254. doi: 10.1016/j.freeradbiomed.2020.10.022. Epub 2020 Oct 21.
Oxidative stress has been associated with pathogenesis in several diseases including Huntington's disease (HD), a neurodegenerative disorder caused by a mutation in the huntingtin gene. Oxidative stress induced reactive oxygen species (ROS) are normally controlled at the cellular level by the nuclear factor (erythroid-derived 2)-like 2 (NRF2) a transcription factor that regulates the expression of various antioxidants and detoxifying proteins. Normally NRF2 is largely inactivated in the cytoplasm by the Kelch-like ECH-associated protein 1 (KEAP1)/Cullin-3 (CUL3) mediated ubiquitination and subsequent proteosomal degradation. In the presence of ROS, KEAP1 sensor cysteines are directly or indirectly engaged resulting in NRF2 release, nuclear translocation, and activation of its target genes. Consequently the activation of NRF2 by a small-molecule drug may have the therapeutic potential to control oxidative stress by upregulation of the endogenous antioxidant responses. Here we attempted to validate the use of a reversible non-acidic KEAP1 binder (Compound 2) to activate NRF2 with better cellular activity than similar acidic compounds. When tested head to head with sulforaphane, a covalent KEAP1 binder, Compound 2 had a similar ability to induce the expression of genes known to be modulated by NRF2 in neurons and astrocytes isolated from wild-type rat, wild type mouse and zQ175 (an HD mouse model) embryos. However, while sulforaphane also negatively affected genes involved in neurotoxicity in these cells, Compound 2 showed a clean profile suggesting its mode of action has lower off-target activity. We show that Compound 2 was able to protect cells from an oxidative insult by preserving the ATP content and the mitochondrial potential of primary astrocytes, consistent with the hypothesis that neurotoxicity induced by oxidative stress can be limited by upregulation of innate antioxidant response.
氧化应激与包括亨廷顿病(HD)在内的多种疾病的发病机制有关,HD 是一种由亨廷顿基因突变引起的神经退行性疾病。氧化应激诱导的活性氧(ROS)通常在细胞水平上受到核因子(红系衍生 2)样 2(NRF2)的控制,NRF2 是一种转录因子,可调节各种抗氧化剂和解毒蛋白的表达。正常情况下,NRF2 在细胞质中主要通过 Kelch 样 ECH 相关蛋白 1(KEAP1)/Cullin-3(CUL3)介导的泛素化和随后的蛋白酶体降解而失活。在 ROS 的存在下,KEAP1 传感器半胱氨酸直接或间接参与,导致 NRF2 释放、核易位和其靶基因的激活。因此,通过小分子药物激活 NRF2 可能具有通过上调内源性抗氧化反应来控制氧化应激的治疗潜力。在这里,我们试图验证使用可逆非酸性 KEAP1 结合物(化合物 2)来激活 NRF2,其细胞活性优于类似的酸性化合物。当与 Sulforaphane(一种共价 KEAP1 结合物)进行头对头测试时,化合物 2 具有相似的能力,可诱导从野生型大鼠、野生型小鼠和 zQ175(HD 小鼠模型)胚胎中分离的神经元和星形胶质细胞中已知受 NRF2 调节的基因的表达。然而,虽然 Sulforaphane 也会对这些细胞中的神经毒性相关基因产生负面影响,但化合物 2 表现出清晰的特征,表明其作用模式的脱靶活性较低。我们表明,化合物 2 能够通过维持原代星形胶质细胞的 ATP 含量和线粒体电位来保护细胞免受氧化应激的损伤,这与氧化应激诱导的神经毒性可以通过上调固有抗氧化反应来限制的假设一致。