Lashley Tammaryn, Tossounian Maria-Armineh, Costello Heaven Neve, Wallworth Samantha, Peak-Chew Sew, Bradshaw Aaron, Cooper J Mark, de Silva Rohan, Srai Surjit Kaila, Malanchuk Oksana, Filonenko Valeriy, Koopman Margreet B, Rüdiger Stefan G D, Skehel Mark, Gout Ivan
Queen Square Brain Bank, UCL Queen Square Institute of Neurology, London, United Kingdom.
Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, United Kingdom.
Front Cell Neurosci. 2021 Oct 15;15:739425. doi: 10.3389/fncel.2021.739425. eCollection 2021.
Alzheimer's disease (AD) is a neurodegenerative disorder, accounting for at least two-thirds of dementia cases. A combination of genetic, epigenetic and environmental triggers is widely accepted to be responsible for the onset and development of AD. Accumulating evidence shows that oxidative stress and dysregulation of energy metabolism play an important role in AD pathogenesis, leading to neuronal dysfunction and death. Redox-induced protein modifications have been reported in the brain of AD patients, indicating excessive oxidative damage. Coenzyme A (CoA) is essential for diverse metabolic pathways, regulation of gene expression and biosynthesis of neurotransmitters. Dysregulation of CoA biosynthesis in animal models and inborn mutations in human genes involved in the CoA biosynthetic pathway have been associated with neurodegeneration. Recent studies have uncovered the antioxidant function of CoA, involving covalent protein modification by this cofactor (CoAlation) in cellular response to oxidative or metabolic stress. Protein CoAlation has been shown to both modulate the activity of modified proteins and protect cysteine residues from irreversible overoxidation. In this study, immunohistochemistry analysis with highly specific anti-CoA monoclonal antibody was used to reveal protein CoAlation across numerous neurodegenerative diseases, which appeared particularly frequent in AD. Furthermore, protein CoAlation consistently co-localized with tau-positive neurofibrillary tangles, underpinning one of the key pathological hallmarks of AD. Double immunihistochemical staining with tau and CoA antibodies in AD brain tissue revealed co-localization of the two immunoreactive signals. Further, recombinant 2N3R and 2N4R tau isoforms were found to be CoAlated and the site of CoAlation mapped by mass spectrometry to conserved cysteine 322, located in the microtubule binding region. We also report the reversible HO-induced dimerization of recombinant 2N3R, which is inhibited by CoAlation. Moreover, CoAlation of transiently expressed 2N4R tau was observed in diamide-treated HEK293/Pank1β cells. Taken together, this study demonstrates for the first time extensive anti-CoA immunoreactivity in AD brain samples, which occurs in structures resembling neurofibrillary tangles and neuropil threads. Covalent modification of recombinant tau at cysteine 322 suggests that CoAlation may play an important role in protecting redox-sensitive tau cysteine from irreversible overoxidation and may modulate its acetyltransferase activity and functional interactions.
阿尔茨海默病（AD）是一种神经退行性疾病，至少占痴呆病例的三分之二。人们普遍认为，遗传、表观遗传和环境触发因素共同作用导致了AD的发病和发展。越来越多的证据表明，氧化应激和能量代谢失调在AD发病机制中起重要作用，导致神经元功能障碍和死亡。据报道，AD患者大脑中存在氧化还原诱导的蛋白质修饰，表明存在过度的氧化损伤。辅酶A（CoA）对多种代谢途径、基因表达调控和神经递质生物合成至关重要。动物模型中CoA生物合成失调以及参与CoA生物合成途径的人类基因的先天性突变与神经退行性变有关。最近的研究发现了CoA的抗氧化功能，即在细胞对氧化或代谢应激的反应中，该辅因子通过共价修饰蛋白质（CoAlation）发挥作用。蛋白质CoAlation已被证明既能调节修饰后蛋白质的活性，又能保护半胱氨酸残基免受不可逆的过度氧化。在本研究中，使用高度特异性的抗CoA单克隆抗体进行免疫组织化学分析，以揭示多种神经退行性疾病中的蛋白质CoAlation情况，这种情况在AD中尤为常见。此外，蛋白质CoAlation始终与tau阳性神经原纤维缠结共定位，这是AD的关键病理特征之一。在AD脑组织中用tau和CoA抗体进行双重免疫组织化学染色，显示两种免疫反应信号共定位。此外，发现重组2N3R和2N4R tau异构体发生了CoAlation，通过质谱分析确定CoAlation位点为位于微管结合区域的保守半胱氨酸322。我们还报道了重组2N3R的可逆性HO诱导二聚化，CoAlation可抑制这种二聚化。此外，在二硫苏糖醇处理的HEK293/Pank1β细胞中观察到瞬时表达的2N4R tau发生了CoAlation。综上所述，本研究首次证明AD脑样本中存在广泛的抗CoA免疫反应性，这种反应出现在类似神经原纤维缠结和神经毡线的结构中。重组tau在半胱氨酸322处的共价修饰表明，CoAlation可能在保护对氧化还原敏感的tau半胱氨酸免受不可逆的过度氧化方面发挥重要作用，并可能调节其乙酰转移酶活性和功能相互作用。
