Novel therapeutic targets in epilepsy: oxidative stress and iron metabolism

Activatable Dual-Optical Molecular Probe for Bioimaging Superoxide Anion in Epilepsy

Superoxide anion (O2•-) plays a pivotal role in the generation of other reactive oxygen species within the body and is closely linked to epilepsy. Despite this connection, achieving precise imaging of O2•- during epilepsy pathology remains a formidable challenge. Herein, we develop an activatable molecular probe, CL-SA, to track the fluctuation of the level of O2•- in epilepsy through simultaneous fluorescence imaging and chemiluminescence sensing. The developed probe CL-SA demonstrated its efficacy in imaging of O2•- in neuronal cells, showcasing its dual optical imaging capability for O2•- in vitro. Furthermore, CL-SA was successfully used to observe aberrantly expressed O2•- in a mouse model of epilepsy. Overall, CL-SA provides us with a valuable tool for chemical and biomedical studies of O2•-, promoting the investigation of O2•- fluctuations in epilepsy, as well as providing a reliable means to explore the diagnosis and therapy of epilepsy.

Novel Near-Infrared Fluorescence Probe for Bioimaging and Evaluating Superoxide Anion Fluctuations in Ferroptosis-Mediated Epilepsy

Ferroptosis is an iron-regulated, caspase-mediated pathway of cell death that is associated with the excessive aggregation of lipid-reactive oxygen species and is extensively involved in the evolution of many diseases, including epilepsy. The superoxide anion (O2•-), as the primary precursor of ROS, is closely related to ferroptosis-mediated epilepsy. Therefore, it is crucial to establish a highly effective and convenient method for the real-time dynamic monitoring of O2•- during the ferroptosis process in epilepsy for the diagnosis and therapy of ferroptosis-mediated epilepsy. Nevertheless, no probes for detecting O2•- in ferroptosis-mediated epilepsy have been reported. Herein, we systematically conceptualized and developed a novel near-infrared (NIR) fluorescence probe, NIR-FP, for accurately tracking the fluctuation of O2•- in ferroptosis-mediated epilepsy. The probe showed exceptional sensitivity and outstanding selectivity toward O2•-. In addition, the probe has been utilized effectively to bioimage and evaluate endogenous O2•- variations in three types of ferroptosis-mediated epilepsy models (the kainic acid-induced chronic epilepsy model, the pentylenetetrazole-induced acute epilepsy model, and the pilocarpine-induced status epilepticus model). The above applications illustrated that NIR-FP could serve as a reliable and suitable tool for guiding the accurate diagnosis and therapy of ferroptosis-mediated epilepsy.

The increase of Nrf2 m6A modification induced by FTO downregulation promotes hippocampal neuron injury and aggravates the progression of epilepsy in a rat model

Epilepsy is a common chronic neurological disorder characterized by widespread neuronal death. The purpose of this study was to investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) m6A methylation in epilepsy. To create epileptic models, the rats were given Lithium chloride and pilocarpine, and isolated primary rat hippocampal neurons were cultured in an Mg2⁺ -free medium. The frequency of seizures was recorded in the epilepsy group of rats. The functional tests included TUNEL, MTT, and flow cytometry. Mechanistically, RNA degradation assay, RNA immunoprecipitation, and methylated RNA immunoprecipitation were performed. In epileptic models, Nrf2 and fat mass and obesity-associated (FTO) levels were downregulated, whereas YT521-B homology (YTH) domain family protein 2 (YTHDF2) was upregulated. Additionally, in epileptic models, there was a rise in the m6A methylation level of Nrf2 mRNA. Overexpressing FTO increased cell viability and reduced apoptosis, but Nrf2 interference reversed these effects. Meanwhile, FTO overexpression decreased the m6A methylation of Nrf2 mRNA. Moreover, YTHDF2 bound to Nrf2 mRNA and decreased its stability. Furthermore, FTO overexpression reduced seizure frequency in rats and inhibited hippocampal neuron apoptosis via lowering the m6A methylation level of Nrf2 mRNA. Overexpressing FTO reduced m6A methylation of Nrf2 mRNA, increased cell viability, suppressed apoptosis, and slowed the progression of epileptic diseases, which is linked to YTHDF2 binding to m6A-modified Nrf2 and promoting its degradation, as well as downregulating Nrf2 expression in hippocampal neurons.

Polydatin alleviates traumatic brain injury: Role of inhibiting ferroptosis

Secondary injury is the main cause of high mortality and poor prognosis of TBI, which has recently been suggested to be related to ferroptosis. Polydatin, a monocrystalline compound extracted from the rhizome of Polygonum, has been shown to exert potential neuroprotective effects. However, its role and mechanism in the secondary injury of TBI has not been elucidated. In this study, the inhibition of Polydatin on ferroptosis was observed both in the hemoglobin treated Neuro2A cells in vitro and in TBI mouse model in vivo, characterized by reversion of accumulation or deposition of free Fe²⁺, increased content of MDA, decreased activity of key REDOX enzyme GPx4, cell death and tissues loss. Although Polydatin corrected the increased mRNA levels of ferroptosis signaling molecules GPX4, SLC7A11, PTGS2, and ATP5G3 after TBI, TBI and Polydatin treatment had no significant effect on their protein expression. Notably, Polydatin could completely reverse the decrease of GPx4 activity after TBI in vivo and in vitro, and the effect was stronger than that of the classical ferroptosis inhibitor FER-1 in vitro. Further, Polydatin has been shown to reduce the severity of acute neurological impairment and significantly improve subacute motor dysfunction in TBI mice. Our findings provided translational insight into neuroprotection with Polydatin in TBI by inhibiting ferroptosis mainly depending on the maintenance of GPx4 activity.