Novel Concepts for the Role of Chloride Cotransporters in Refractory Seizures

Exploratory analysis of a Novel RACK1 mutation and its potential role in epileptic seizures via Microglia activation

Seizures is a prevalent neurological disorder with a largely elusive pathogenesis. In this study, we identified the key gene RACK1 and its novel mutation RACK1-p.L206P as being associated with seizures through single-cell transcriptome sequencing (scRNA-seq) and whole exome sequencing (WES) techniques. Our findings reveal that the RACK1-p.L206P mutation significantly enhances proliferation, migration, phagocytic ability, and inflammatory activation in human microglia, which in turn affects neuronal excitability and synaptic function, culminating in typical seizure symptoms in the seizures. These effects were further validated in a mouse model using CRISPR/Cas9 gene editing technology. Mutant microglia exhibited increased activation and induced apoptosis in hippocampal neurons, leading to higher action potential frequency and excitatory synaptic marker expression. In vivo experiments demonstrated that RACK1-p.L206P mutant mice displayed classic seizure symptoms, with increased neuronal excitability and a tendency for action potential bursts during initial depolarization, along with more frequent spike discharges. Additionally, excitatory synapse density and size in the hippocampal CA1 region of mutant mice were significantly elevated, accompanied by increased expression of VGLUT1 and PSD95 within microglia. This study offers novel insights into the molecular mechanisms underlying seizures in the seizures and presents valuable clues for the development of future therapeutic strategies.

Molecular Mechanisms of Epilepsy: The Role of the Chloride Transporter KCC2

Epilepsy is a neurological disease characterized by abnormal or synchronous brain activity causing seizures, which may produce convulsions, minor physical signs, or a combination of symptoms. These disorders affect approximately 65 million people worldwide, from all ages and genders. Seizures apart, epileptic patients present a high risk to develop neuropsychological comorbidities such as cognitive deficits, emotional disturbance, and psychiatric disorders, which severely impair quality of life. Currently, the treatment for epilepsy includes the administration of drugs or surgery, but about 30% of the patients treated with antiepileptic drugs develop time-dependent pharmacoresistence. Therefore, further investigation about epilepsy and its causes is needed to find new pharmacological targets and innovative therapeutic strategies. Pharmacoresistance is associated to changes in neuronal plasticity and alterations of GABA_A receptor-mediated neurotransmission. The downregulation of GABA inhibitory activity may arise from a positive shift in GABA_A receptor reversal potential, due to an alteration in chloride homeostasis. In this paper, we review the contribution of K⁺-Cl^--cotransporter (KCC2) to the alterations in the Cl^- gradient observed in epileptic condition, and how these alterations are coupled to the increase in the excitability.

Animal Models of Epilepsy: A Phenotype-oriented Review

Epilepsy is a serious neurological disorder characterized by abnormal, recurrent, and synchronous discharges in the brain. Long-term recurrent seizure attacks can cause serious damage to brain function, which is usually observed in patients with temporal lobe epilepsy. Controlling seizure attacks is vital for the treatment and prognosis of epilepsy. Animal models, such as the kindling model, which was the most widely used model in the past, allow the understanding of the potential epileptogenic mechanisms and selection of antiepileptic drugs. In recent years, various animal models of epilepsy have been established to mimic different seizure types, without clear merits and demerits. Accordingly, this review provides a summary of the views mentioned above, aiming to provide a reference for animal model selection.

Neurological and Neurodegenerative Disorders: Novel Concepts and Treatment

The journal "Aging and Disease" has released a special issue focused on novel concepts in understanding the pathophysiology and treatment of neurological and neurodegenerative disorders. The special issue comprises review and original research articles discussing the various disease mechanisms and/or treatment updates on aging, mild cognitive impairment, dementia, acute stroke, pediatric stroke, super-refractory status epilepticus, reflex epilepsy, drug-resistant epilepsy, Parkinson's disease, and traumatic brain injury. This editorial discusses the highlights from these articles.