SAD-B modulates epileptic seizure by regulating AMPA receptors in patients with temporal lobe epilepsy and in the PTZ-induced epileptic model

Redox Regulation of Brain Selective Kinases BRSK1/2: Implications for Dynamic Control of the Eukaryotic AMPK family through Cys-based mechanisms

In eukaryotes, protein kinase signaling is regulated by a diverse array of post-translational modifications (PTMs), including phosphorylation of Ser/Thr residues and oxidation of cysteine (Cys) residues. While regulation by activation segment phosphorylation of Ser/Thr residues is well understood, relatively little is known about how oxidation of cysteine residues modulate catalysis. In this study, we investigate redox regulation of the AMPK-related Brain-selective kinases (BRSK) 1 and 2, and detail how broad catalytic activity is directly regulated through reversible oxidation and reduction of evolutionarily conserved Cys residues within the catalytic domain. We show that redox-dependent control of BRSKs is a dynamic and multilayered process involving oxidative modifications of several Cys residues, including the formation of intramolecular disulfide bonds involving a pair of Cys residues near the catalytic HRD motif and a highly conserved T-Loop Cys with a BRSK-specific Cys within an unusual CPE motif at the end of the activation segment. Consistently, mutation of the CPE-Cys increases catalytic activity in vitro and drives phosphorylation of the BRSK substrate Tau in cells. Molecular modeling and molecular dynamics simulations indicate that oxidation of the CPE-Cys destabilizes a conserved salt bridge network critical for allosteric activation. The occurrence of spatially proximal Cys amino acids in diverse Ser/Thr protein kinase families suggests that disulfide mediated control of catalytic activity may be a prevalent mechanism for regulation within the broader AMPK family.

AMPK role in epilepsy: a promising therapeutic target?

Epilepsy is a complex and multifaceted neurological disorder characterized by spontaneous and recurring seizures. It poses significant therapeutic challenges due to its diverse etiology and often-refractory nature. This comprehensive review highlights the pivotal role of AMP-activated protein kinase (AMPK), a key metabolic regulator involved in cellular energy homeostasis, which may be a promising therapeutic target for epilepsy. Current therapeutic strategies such as antiseizure medication (ASMs) can alleviate seizures (up to 70%). However, 30% of epileptic patients may develop refractory epilepsy. Due to the complicated nature of refractory epilepsy, other treatment options such as ketogenic dieting, adjunctive therapy, and in limited cases, surgical interventions are employed. These therapy options are only suitable for a select group of patients and have limitations of their own. Current treatment options for epilepsy need to be improved. Emerging evidence underscores a potential association between impaired AMPK functionality in the brain and the onset of epilepsy, prompting an in-depth examination of AMPK's influence on neural excitability and ion channel regulation, both critical factors implicated in epileptic seizures. AMPK activation through agents such as metformin has shown promising antiepileptic effects in various preclinical and clinical settings. These effects are primarily mediated through the inhibition of the mTOR signaling pathway, activation of the AMPK-PI3K-c-Jun pathway, and stimulation of the PGC-1α pathway. Despite the potential of AMPK-targeted therapies, several aspects warrant further exploration, including the detailed mechanisms of AMPK's role in different brain regions, the impact of AMPK under various conditional circumstances such as neural injury and zinc toxicity, the long-term safety and efficacy of chronic metformin use in epilepsy treatment, and the potential benefits of combination therapy involving AMPK activators. Moreover, the efficacy of AMPK activators in refractory epilepsy remains an open question. This review sets the stage for further research with the aim of enhancing our understanding of the role of AMPK in epilepsy, potentially leading to the development of more effective, AMPK-targeted therapeutic strategies for this challenging and debilitating disorder.

Neuroprotection impact of biochanin A against pentylenetetrazol-kindled mice: Targeting NLRP3 inflammasome/TXNIP pathway and autophagy modulation

Recurrent seizures characterize epilepsy, a complicated and multifaceted neurological disease. Several neurological alterations, such as cell death and the growth of gorse fibers, have been linked to epilepsy. The dentate gyrus of the hippocampus is particularly vulnerable to neuronal loss and abnormal neuroplastic changes in the pentylenetetrazol (PTZ) kindling model. Biochanin A has potent anti-inflammatory and antioxidant properties, according to previous evidence and its possible impact in epilepsy has never previously been claimed. The current work aimed to investigate biochanin A's anti-epileptic potential in PTZ-induced kindling model in mice. Chronic epilepsy was established in mice by giving PTZ (35 mg/kg, i.p) every other day for 21 days. Biochanin A (20 mg/kg) was given daily till the end of the experiment. Biochanin A pretreatment significantly reduced the severity of epileptogenesis by 51.7% and downregulated the histological changes in the CA3 region of the hippocampus by 42% along with displaying antioxidant/anti-inflammatory efficacy through upregulated hemeoxygenase-1 (HO-1) and, erythroid 2-related factor 2 (Nrf2) levels in the brain by 1.9-fold and 2-fold respectively, parallel to reduction of malondialdehyde (MDA), myeloperoxidase (MPO), glial fibrillary acidic protein (GFAP) and L-glutamate/IL-1β/TXNIB/NLRP3 axis. Moreover, biochanin A suppressed neuronal damage by reducing the astrocytes' activation and significantly attenuated the PTZ-induced increase in LC3 levels by 55.5%. Furthermore, molecular docking findings revealed that BIOCHANIN A has a higher affinity for phosphoinositide 3-kinase (PI3k), threonine kinase2 (AKT2), and mammalian target of rapamycin complex 1 (mTORC1) indicating the neuroprotective and anti-epileptic characteristics of biochanin A in the brain tissue of PTZ-kindled mice.

Vitamin E Exerts Neuroprotective Effects in Pentylenetetrazole Kindling Epilepsy via Suppression of Ferroptosis

Epilepsy is one of the most common chronic neurological diseases. There is increasing evidence for ferroptosis playing an important role in the occurrence and development of epilepsy. Vitamin E is a common fat-soluble antioxidant that can regulate ferroptosis. The aim of this study was to investigate the effects of vitamin E on ferroptosis of hippocampal neurons in epileptic rats. Sixty-four male Sprague-Dawley (SD) rats were randomly divided into control, pentylenetetrazol (PTZ; 35 mg/kg), vitamin E (200 mg/kg) + PTZ, and Ferrostatin-1 (Fer-1; 2.5 μmol/kg) + PTZ groups, with drugs administered intraperitoneally 15 times every other day for 29 days. The behavioral manifestations (epileptic score, latency, and number of seizures in 30 min) and EEG changes were observed and recorded. Nissl staining and electrophysiological recording were used to assess neuronal damage and excitability in the hippocampal CA1 region, respectively. The levels of iron, glutathione (GSH), and malondialdehyde (MDA) in the hippocampus were assessed by spectrophotometry. Immunofluorescence staining was used to detect lipoxygenase 15 (15-LOX) expression. Western blot was used to determine glutathione peroxidase 4 (GPX4) and 15-LOX protein levels. Vitamin E treatment was associated with decreased epileptic grade, seizure latency, and number of seizures in the PTZ-kindled epileptic model. Vitamin E treatment also decreased 15-LOX expression, inhibited MDA and iron accumulation, and increased GPX4 and GSH expression. In conclusion, vitamin E can reduce neuronal ferroptosis and seizures by inhibiting 15-LOX expression.

HAP1 Modulates Epileptic Seizures by Regulating GABAAR Function in Patients with Temporal Lobe Epilepsy and in the PTZ-Induced Epileptic Model

The number of γ-aminobutyric acid type A receptors (GABA_ARs) expressed on the surface membrane and at synaptic sites is implicated in the enhanced excitation of neuronal circuits and abnormal network oscillations in epilepsy. Huntingtin-associated protein 1 (HAP1), a key mediator of pathological alterations in protein trafficking, directly interacts with GABA_ARs and facilitates their recycling back to synapses after internalization from the surface; thus, HAP1 regulates the strength of inhibitory synaptic transmission. Here, we show that HAP1 modulates epileptic seizures by regulating GABA_AR function in patients with temporal lobe epilepsy (TLE) and in the pentylenetetrazol (PTZ)-induced epileptic model. We demonstrate that GABA_ARβ^2/3 and HAP1 expression are decreased and that the HAP1-GABA_ARβ^2/3 complex is disrupted in the epileptic rat brain. We found that HAP1 upregulation exerts antiepileptic activity in the PTZ-induced seizure and that these changes are associated with increased surface GABA_ARβ^2/3 expression and the amplitude of miniature inhibitory postsynaptic currents (mIPSCs). This study provides evidence that hippocampal HAP1 is linked to GABA_ARs in evoking seizures and suggests that this mechanism is involved in epileptic seizures in the brain, representing a potential therapeutic target for epilepsy.