The Clock gene regulates kainic acid-induced seizures through inhibiting ferroptosis in mice

Identification and validation of diagnostic biomarkers for temporal lobe epilepsy related to ferroptosis and potential therapeutic targets

Ferroptosis pathway activation is potentially correlated with temporal lobe epilepsy (TLE). However, the diagnostic significance and mechanism of ferroptosis-related genes (FRGs) in TLE require further investigation. A comprehensive analysis of the GSE134697 dataset from the Gene Expression Omnibus (GEO) database using Weighted gene co-expression network analysis (WGCNA) identified 3,212 differentially expressed genes (DEGs) between temporal lobe epilepsy (TLE) and control groups, with a critical focus on the turquoise module. Through intersection of DEGs and key module genes, correlation analyses with functional-related genes (FRG), protein-protein interactions (PPI), least absolute shrinkage and selection operator (LASSO), and machine learning methods, five potential biomarkers of ferroptosis (CBS, SHMT1, RIN3, QDPR, and PLPP4) were isolated. A nomogram was constructed using these markers, and enrichment analyses revealed their links to T-cell activation, allograft rejection, and glial differentiation. Variations in 13 immune cell types were also noted. Upregulation of CBS, RIN3, QDPR, and PLPP4 in TLE was confirmed through RT-qPCR and Western blot assays. Additionally, five SHMT1-targeting and one CBS-targeting drugs were predicted using the Drug-Gene Interaction Database (DGIdb). These findings provide new insights into the potential pathogenesis of TLE and suggest new targets for future research.

Understanding the intricacies of cellular mechanisms in remyelination: The role of circadian rhythm

The term "circadian rhythm" refers to the 24-h oscillations found in various physiological processes in organisms, responsible for maintaining bodily homeostasis. Many neurological diseases mainly involve the process of demyelination, and remyelination is crucial for the treatment of neurological diseases. Current research mainly focuses on the key role of circadian clocks in the pathophysiological mechanisms of multiple sclerosis. Various studies have shown that the circadian rhythm regulates various cellular molecular mechanisms and signaling pathways involved in remyelination. The process of remyelination is primarily mediated by oligodendrocyte precursor cells (OPCs), oligodendrocytes, microglia, and astrocytes. OPCs are activated, proliferate, migrate, and ultimately differentiate into oligodendrocytes after demyelination, involving many key signaling pathway and regulatory factors. Activated microglia secretes important cytokines and chemokines, promoting OPC proliferation and differentiation, and phagocytoses myelin debris that inhibits remyelination. Astrocytes play a crucial role in supporting remyelination by secreting signals that promote remyelination or facilitate the phagocytosis of myelin debris by microglia. Additionally, cell-to-cell communication via gap junctions allows for intimate contact between astrocytes and oligodendrocytes, providing metabolic support for oligodendrocytes. Therefore, gaining a deeper understanding of the mechanisms and molecular pathways of the circadian rhythm at various stages of remyelination can help elucidate the fundamental characteristics of remyelination and provide insights into treating demyelinating disorders.

Biochanin A inhibits excitotoxicity-triggered ferroptosis in hippocampal neurons

Excitatory neurotransmitter-induced neuronal ferroptosis has been implicated in multiple neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Although there are several reports pertaining to the pharmacological activities of biochanin A, the effects of this isoflavone on excitotoxicity-triggered neuronal ferroptosis remain unclear. In this study, we demonstrate that biochanin A inhibits ferroptosis of mouse hippocampal neurons induced by glutamate or the glutamate analog, kainic acid. Biochanin A significantly inhibited accumulation of intracellular iron and lipid peroxidation in glutamate- or kainic acid-treated mouse hippocampal neurons. Furthermore, biochanin A regulated the level of glutathione peroxidase 4, a master regulator of ferroptosis, by modulating its autophagy-dependent degradation. We observed that biochanin A reduced the glutamate-induced accumulation of intracellular iron by regulating expression of iron metabolism-related proteins including ferroportin-1, divalent metal transferase 1, and transferrin receptor 1. Taken together, these results indicate that biochanin A effectively inhibits hippocampal neuronal death triggered by glutamate or kainic acid. Our study is the first to report that biochanin A has therapeutic potential for the treatment of diseases associated with hippocampal neuronal death, particularly ferroptosis induced by excitatory neurotransmitter.

Research Progress of Traditional Chinese Medicine in Treating Central Nervous System Diseases by Modulating Ferroptosis

A newly proposed form of programmed cell death, ferroptosis, is distinct in cellular morphology, biochemical characteristics, and genetic characteristics from apoptosis, autophagy, and necrosis. Its mechanisms primarily encompass iron overload, lipid peroxidation, and amino acid metabolisms. Extensive research confirms that ferroptosis is linked to the onset and progression of various diseases that pose a threat to the central nervous system (CNS), offering new directions and targets for the mechanistic study and pharmacotherapy of CNS diseases. Traditional Chinese Medicine (TCM), encompassing herbal medicines (extracts, compound formulations, injections, etc.), acupuncture, and moxibustion, boasts advantages over other treatments, such as multi-pathway and multi-target approaches and high safety. TCM has also demonstrated good efficacy in treating CNS diseases. Numerous studies indicate that TCM can modulate ferroptosis to treat CNS diseases, showing promising research prospects. This paper briefly outlines the pathways and mechanisms of ferroptosis and systematically summarizes the current status and progress of TCM in regulating various CNS diseases through the ferroptosis pathway, providing new insights and directions for future TCM treatments of CNS diseases.

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 ferroptosis inducer RSL3 triggers interictal epileptiform activity in mice cortical neurons

Epilepsy is a neurological disorder characterized by recurrent seizures, which result from excessive, synchronous discharges of neurons in different brain areas. In about 30% of cases, epileptic discharges, which vary in their etiology and symptomatology, are difficult to treat with conventional drugs. Ferroptosis is a newly defined iron-dependent programmed cell death, characterized by excessive accumulation of lipid peroxides and reactive oxygen species. Evidence has been provided that ferroptosis is involved in epilepsy, and in particular in those forms resistant to drugs. Here, whole cell patch clamp recordings, in current and voltage clamp configurations, were performed from layer IV principal neurons in cortical slices obtained from adult mouse brain. Application of the ferroptosis inducer RAS-selective lethal 3 (RSL3) induced interictal epileptiform discharges which started at RSL3 concentrations of 2 μM and reached a plateau at 10 μM. This effect was not due to changes in active or passive membrane properties of the cells, but relied on alterations in synaptic transmission. In particular, interictal discharges were dependent on the excessive excitatory drive to layer IV principal cells, as suggested by the increase in frequency and amplitude of spontaneously occurring excitatory glutamatergic currents, possibly dependent on the reduction of inhibitory GABAergic ones. This led to an excitatory/inhibitory unbalance in cortical circuits. Interictal bursts could be prevented or reduced in frequency by the lipophilic antioxidant Vitamin E (30 μM). This study allows identifying new targets of ferroptosis-mediated epileptic discharges opening new avenues for the treatment of drug-resistant forms of epilepsy.

Targeting ferroptosis as novel therapeutic approaches for epilepsy

Epilepsy is a chronic disorder of the central nervous system characterized by recurrent unprovoked seizures resulting from excessive synchronous discharge of neurons in the brain. As one of the most common complications of many neurological diseases, epilepsy is an expensive and complex global public health issue that is often accompanied by neurobehavioral comorbidities, such as abnormalities in cognition, psychiatric status, and social-adaptive behaviors. Recurrent or prolonged seizures can result in neuronal damage and cell death; however, the molecular mechanisms underlying the epilepsy-induced damage to neurons remain unclear. Ferroptosis, a novel type of regulated cell death characterized by iron-dependent lipid peroxidation, is involved in the pathophysiological progression of epilepsy. Emerging studies have demonstrated pharmacologically inhibiting ferroptosis can mitigate neuronal damage in epilepsy. In this review, we briefly describe the core molecular mechanisms of ferroptosis and the roles they play in contributing to epilepsy, highlight emerging compounds that can inhibit ferroptosis to treat epilepsy and associated neurobehavioral comorbidities, and outline their pharmacological beneficial effects. The current review suggests inhibiting ferroptosis as a therapeutic target for epilepsy and associated neurobehavioral comorbidities.

Role of Wnt/β-catenin signaling pathway in ameloblast differentiation in relevance to dental fluorosis

Excess consumption of fluoride during the development of tooth enamel will cause dental fluorosis, but the exact molecular mechanisms remain to be elucidated. Circadian rhythm is implicated in many physiological processes and various diseases. There is increasing evidence indicates that ameloblast differentiation is under the control of clock genes. However, it has not been reported whether fluoride regulates ameloblast differentiation through clock genes and the downstream PPARγ. To explore the effect of fluoride on ameloblast differentiation and the underlying regulatory mechanism, we used both rat dental fluorosis model and an ameloblast cell line LS8 to conduct a series of experiments. Our results showed that fluoride significantly reduced the expression of PCNA, RUNX2 and MMP9 in rat ameloblasts and LS8 cells (P < 0.05). Fluoride increased nuclear translocation of β-catenin in vivo and in vitro, and 0.1 μg/ml Dkk1 pretreatment ameliorated the decreased expression of CXXC5, RUNX2 and MMP9 induced by fluoride. Furthermore, we found fluoride significantly inhibited the expression of Clock, Bmal1, Per2 and PPARγ in rat mandibular ameloblasts and LS8 cells by immunostaining, qPCR and Western blot (P < 0.05). Flow cytometry analysis showed that fluoride promoted ROS generation. Remarkably, 50 μM resveratrol significantly ameliorated the inhibitory effect of fluoride on ameloblast differentiation markers, clock genes and PPARγ, and inhibited the Wnt/β-catenin signaling (P < 0.05). Taken together, these findings suggested that excessive fluoride promoted ROS generation, leading to the inhibition of clock genes, which resulted in reduced PPARγ and activated Wnt/β-catenin signaling pathway, thus inhibiting ameloblast differentiation and matrix degradation. This study provides a better understanding of the molecular mechanism of enamel defects in dental fluorosis.