Jin Yiming, Wang Xinxin, Xu Xiaowen, Zhou Xiuwen, Wang Qing, Zhang Li, Li Lili, Jin Meifang, Ni Hong
Department of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, Jiangsu Province, China.
Department of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, Jiangsu Province, China; Laboratory of Pediatric Research, Children's Hospital of Wujiang District, Suzhou, Jiangsu Province, China.
Redox Biol. 2025 Jul 29;86:103792. doi: 10.1016/j.redox.2025.103792.
BACKGROUND: Hypoxic-ischemic brain damage (HIBD) is a predominant cause of neuronal injury and mortality in newborns. Current preventive and therapeutic interventions demonstrate limited clinical efficacy. Emerging evidence reveals ferroptosis as a critical mechanism within HIBD pathophysiology, positioning it as a promising therapeutic target. Dimethyl malonate (DMM), a competitive inhibitor of succinate dehydrogenase, has demonstrated neuroprotective properties across multiple models of neurological disorders. However, the impact of DMM on the neonatal HIBD has not been studied. AIM: To investigate the neuroprotective effects of DMM against neonatal HIBD and elucidate its mechanisms of action. METHODS: We created a model of HIBD in neonatal male C57BL/6J mice and administered various doses of DMM or vehicle control. Quantitative assessments included cerebral infarct volume measurement, Nissl staining for neurons, neurological behavior, ferrous ion (Fe), malondialdehyde (MDA) level, 4-hydroxynonenal (4-HNE) expression, and solute carrier family 7 member 11 (SLC7A11, system Xc)/glutathione peroxidase 4 (GPX4) antioxidant axis expression level. Parallel studies in vitro employed oxygen-glucose deprivation/reperfusion-treated HT22 cells to investigate the effects of DMM on ferroptosis and its underlying mechanisms. Moreover, key factors of ferritinophagy, including nuclear receptor coactivator 4 (NCOA4), SQSTM1/p62, ferritin heavy chain 1 (FTH1), and microtubule-associated protein light 3 II (LC3II) were analyzed by western blotting. Molecular interactions between NCOA4 and FTH1 in brain cortical tissues of DMM-treated HIBD mice were analyzed by coimmunoprecipitation (Co-IP). Ferroptosis regulation by DMM was further investigated via Fth1 knockdown in cellular models. Immunofluorescence staining was used to evaluate the capacity of DMM to suppress ferritin degradation and lysosomal Fe accumulation at the organelle level. RESULTS: DMM treatment demonstrated its neuroprotective efficacy in HIBD models, as evidenced by a reduction in cerebral infarct volume, an increase in the number of Nissl-positive neurons, and improved cognitive and motor functions in neonatal mice compared with controls. Additionally, the DMM intervention significantly modulated ferroptosis-related biomarkers in brain cortical tissues and HT22 cells, decreasing ferrous ion (Fe) accumulation, reducing lipid peroxidation products (MDA and 4-HNE), and enhancing SLC7A11/GPX4 antioxidant system activity. Importantly, DMM specifically regulated core ferritinophagy components: suppressing NCOA4 and LC3II expression while upregulating FTH1 and p62 levels. Co-IP revealed that mechanistically, DMM disrupted the protein interaction between NCOA4 and FTH1, effectively inhibiting ferritinophagy progression. The effects of antiferroptosis were FTH1-dependent, as demonstrated by reversal of the DMM protective effect following Fth1 knockdown in vitro. Immunofluorescence analysis showed that DMM decreased the colocalization of FTH1-lysosome-associated membrane protein 2, and FerroOrange/LysoTracker Green dual staining confirmed its inhibition of lysosomal iron accumulation, collectively indicating regulation of DMM at the organelle level. CONCLUSION: DMM suppressed ferroptosis-induced neuronal death by specifically targeting FTH1 and disrupting the NCOA4-FTH1 interaction, thereby mitigating HIBD. These findings position DMM as a promising therapeutic candidate for the clinical management of neonatal hypoxic-ischemic encephalopathy.
背景:缺氧缺血性脑损伤(HIBD)是新生儿神经元损伤和死亡的主要原因。目前的预防和治疗干预措施临床疗效有限。新出现的证据表明,铁死亡是HIBD病理生理学中的一个关键机制,使其成为一个有前景的治疗靶点。丙二酸二甲酯(DMM)是琥珀酸脱氢酶的竞争性抑制剂,已在多种神经疾病模型中显示出神经保护特性。然而,DMM对新生儿HIBD的影响尚未得到研究。 目的:研究DMM对新生儿HIBD的神经保护作用,并阐明其作用机制。 方法:我们在新生雄性C57BL/6J小鼠中建立了HIBD模型,并给予不同剂量的DMM或溶剂对照。定量评估包括脑梗死体积测量、神经元尼氏染色、神经行为、亚铁离子(Fe)、丙二醛(MDA)水平、4-羟基壬烯醛(4-HNE)表达以及溶质载体家族7成员11(SLC7A11,系统Xc)/谷胱甘肽过氧化物酶4(GPX4)抗氧化轴表达水平。体外平行研究采用氧糖剥夺/再灌注处理的HT22细胞,以研究DMM对铁死亡及其潜在机制的影响。此外,通过蛋白质印迹分析铁自噬的关键因子,包括核受体辅激活因子4(NCOA4)、SQSTM1/p62、铁蛋白重链1(FTH1)和微管相关蛋白轻链3 II(LC3II)。通过免疫共沉淀(Co-IP)分析DMM处理的HIBD小鼠脑皮质组织中NCOA4与FTH1之间的分子相互作用。通过在细胞模型中敲低Fth1进一步研究DMM对铁死亡的调节作用。免疫荧光染色用于评估DMM在细胞器水平抑制铁蛋白降解和溶酶体铁积累的能力。 结果:DMM治疗在HIBD模型中显示出神经保护作用,表现为脑梗死体积减小、尼氏阳性神经元数量增加,与对照组相比,新生小鼠的认知和运动功能得到改善。此外,DMM干预显著调节了脑皮质组织和HT22细胞中铁死亡相关生物标志物,减少了亚铁离子(Fe)积累,降低了脂质过氧化产物(MDA和4-HNE),并增强了SLC7A11/GPX4抗氧化系统活性。重要的是,DMM特异性调节核心铁自噬成分:抑制NCOA4和LC3II表达,同时上调FTH1和p62水平。Co-IP表明,从机制上讲,DMM破坏了NCOA4与FTH1之间的蛋白质相互作用,有效抑制了铁自噬进程。抗铁死亡作用依赖于FTH1,体外敲低Fth1后DMM的保护作用逆转证明了这一点。免疫荧光分析表明,DMM降低了FTH1与溶酶体相关膜蛋白2的共定位,FerroOrange/LysoTracker Green双重染色证实其抑制了溶酶体铁积累,共同表明DMM在细胞器水平的调节作用。 结论:DMM通过特异性靶向FTH1并破坏NCOA4-FTH1相互作用,抑制铁死亡诱导的神经元死亡,从而减轻HIBD。这些发现使DMM成为新生儿缺氧缺血性脑病临床治疗的一个有前景的候选药物。
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