Search Results (315)

EZH2, the catalytic subunit of polycomb repressive complex 2 (PRC2), plays a critical role in neural development by regulating gene expression through the trimethylation of lysine 27 on histone H3 (H3K27me3), which promotes chromatin remodeling and transcriptional repression. Although PRC2 is known to regulate cell fate specification and gliogenesis, its in vivo functions during vertebrate neurodevelopment, particularly at the level of neuronal subtype differentiation, remain incompletely understood. Here, we investigated the consequences of ezh2 loss-of-function during zebrafish brain development, focusing on oligodendrocyte differentiation, cerebellar neurogenesis, and the formation of neurotransmitter-specific neuronal populations. Using whole-mount in situ hybridization, we found that ezh2 inactivation does not alter the expression of oligodendrocyte lineage markers, indicating that early oligodendrocyte precursor cell specification and myelination are preserved. However, a significant reduction in cerebellar proliferation was observed in ezh2-deficient larvae, as evidenced by the downregulation of pcna and cyclin A2, while other brain regions remained unaffected. Notably, the expression of atoh1c, a key marker of glutamatergic cerebellar progenitors, was strongly reduced at 5 days post fertilization, suggesting a selective role for ezh2 in maintaining cerebellar progenitor identity. This was associated with impaired differentiation of both glutamatergic granule cells and GABAergic Purkinje cells in specific cerebellar subregions. In contrast, the expression of markers for other major neurotransmitter systems remained unaffected, indicating a region-specific requirement for ezh2 in neuronal development. Finally, behavioral analysis revealed a hyperlocomotor phenotype in ezh2^−/− larvae, consistent with cerebellar dysfunction. Together, these findings identify ezh2 as a key regulator of progenitor maintenance and neuronal differentiation in the cerebellum, highlighting its crucial role in establishing functional cerebellar circuits. Full article

Traumatic brain injury (TBI) results in a cascade of neuropathological events, which can significantly disrupt synaptic integrity. This review explores the acute, subacute and chronic phases of synaptic dysfunction and loss in trauma which commence post-TBI, and their contribution to the subsequent neurological sequelae. Central to these disruptions is the loss of dendritic spines and impaired synaptic plasticity, which compromise neuronal connectivity and signal transmission. During the acute phase of TBI, mechanical injury triggers presynaptic glutamate secretion and Ca²⁺ ion-mediated excitotoxic injury, accompanied by cerebral edema, mitochondrial dysfunction and the loss of the mushroom-shaped architecture of the dendritic spines. The subacute phase is marked by continued glutamate excitotoxicity and GABAergic disruption, along with neuroinflammatory pathology and autophagy. In the chronic phase, long-term structural remodeling and reduced synaptic densities are evident. These chronic alterations underlie persistent cognitive and memory deficits, mood disturbances and the development of post-traumatic epilepsy. Understanding the phase-specific progression of TBI-related synaptic dysfunction is essential for targeted interventions. Novel therapeutic strategies primarily focus on how to effectively counter acute excitotoxicity and neuroinflammatory cascades. Future approaches may benefit from boosting synaptic repair and modulating neurotransmitter systems in a phase-specific manner, thereby mitigating the long-term impact of TBI on neuronal function. Full article

γ-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the central nervous system (CNS), regulates neuronal excitability, synaptic plasticity, and oscillatory activity essential for cognition, emotion, and behavior. Disruptions in GABAergic signaling are increasingly recognized as key contributors to a range of neurodevelopmental disorders (NDDs), including schizophrenia (SZ), autism spectrum disorder (ASD), major depressive disorder (MDD), bipolar disorder (BD), and intellectual disability (ID). In this review, we analyze the data available from the literature concerning the components of the GABA pathway. We describe the main steps of GABA metabolism, including GABA synthesis and release, GABA receptors neurotransmission, GABA reuptake and catabolism, and evaluate their involvement in the pathogenesis of neurodevelopmental disorders. We suggest the possibility of existence of so far undescribed mechanisms which maintain the concentrations of GABA at a relatively physiological level when the function of glutamic acid decarboxylases is compromised by mutations. Searching for these mechanisms could be important for better understanding neurodevelopment and could give a clue for future searches for new therapeutic approaches for treating or alleviating the symptoms of BD and SZ. We also argue that the metabolic stage of the GABA pathway has only a minor direct effect on GABA signaling and rather causes clinical effects due to accumulation of neurotoxic byproducts. Full article

Background: Shentong Zhuyu Decoction (STZYD) is a traditional Chinese medicine formula that has shown promise in alleviating neuropathic pain (NPP), yet its central mechanisms remain unclear. Methods: We investigated the STZYD effects on NPP using network pharmacology, in vivo assays, and analytical chemistry, focusing on molecular pathways and GABAergic neuronal modulation. Results: Network pharmacology revealed 254 potential STZYD targets enriched in calcium signaling and GABAergic synapse pathways, especially the NMDAR-2B/CaMKII/CREB axis. High-dose STZYD (1.25 g·mL⁻¹) and ifenprodil (6 mg·kg⁻¹) reversed hyperalgesia and anxiety-like behaviors in spared nerve injury (SNI) mice, and microdialysis showed that STZYD and ifenprodil reduced the glutamate, D-serine, aspartate, glycine, and gamma-aminobutyric acid levels in the interpeduncular nucleus (IPN). Immunofluorescence and fiber photometry showed reduced c-Fos expression and suppressed GCaMP signals in IPN GABAergic neurons, with chemogenetic experiments confirming their role in pain modulation. Multimodal molecular biology experiments demonstrated that STZYD and ifenprodil significantly downregulated the GluN2B, p-CaMKII, and p-CREB expressions within the IPN. We identified 145 constituents in STZYD through high-resolution mass spectrometry analysis, among which 40 were absorbed into plasma and 7 were able to cross the blood–brain barrier and accumulate in the IPN. Molecular docking revealed the strong binding of licoricesaponin K2 and senkyunolide F to NMDAR-2B. Conclusions: STZYD exerts dose-dependent antinociceptive effects by modulating IPN GABAergic neuronal activity through the inhibition of the NMDAR-2B-mediated CaMKII/CREB pathway. Full article

Neuronal chloride (Cl⁻) homeostasis is fundamental for brain function, with disruptions increasingly recognized as pathogenic across neurological disorders. This review synthesizes evidence from preclinical models and clinical studies, integrating electrophysiological measurements, molecular analyses, imaging with genetically encoded sensors like ClopHensor, and behavioral assays. Key findings demonstrate that Cl⁻ dysregulation follows distinct patterns: (1) in epilepsy, KCC2 downregulation converts GABAergic inhibition to excitation, promoting seizures; (2) in Alzheimer’s disease (AD) models, pre-symptomatic KCC2 loss in hippocampus is observed, with KCC2 restoration reversing aspects of cognitive decline; (3) in autism spectrum disorders (ASD), developmental delays in GABA polarity shifts feature due to altered NKCC1/KCC2 ratios; and (4) in Huntington’s disease (HD), striatal neuron-specific Cl⁻ imbalances are linked to motor dysfunction. Methodologically, advanced tools—including subcellular Cl⁻ imaging and high-throughput drug screening—have enabled precise dissection of these mechanisms. Therapeutic strategies targeting Cl⁻ transporters (NKCC1 inhibitors like bumetanide, KCC2 enhancers like CLP290) show preclinical promise but require improved central nervous system (CNS) delivery and selectivity. These findings establish Cl⁻ homeostasis as both a biomarker and therapeutic target, necessitating precision medicine approaches to address heterogeneity in neurological disorders. Full article

The rare and rapidly progressive neurodegenerative disease multiple system atrophy (MSA) mainly affects the striatum and other subcortical brain regions. In this atypical Parkinsonian syndrome, the protein alpha-synuclein aggregates and misfolds in neurons as well as glial cells and is released in elevated amounts by hypoexcitable neurons. Mitochondrial dysregulation affects the biosynthesis of coenzyme Q10 and the activity of the respiratory chain, as shown in an induced pluripotent stem cell (iPSC) model. Proteome studies of cerebrospinal fluid and brain tissue from MSA patients yielded inconsistent results regarding possible protein changes due to small and combined groups of atypical Parkinsonian syndromes. In this study, we analysed the cellular proteome of MSA patient-derived striatal GABAergic medium spiny neurons. We observed 25 significantly upregulated and 16 significantly downregulated proteins in MSA cell lines compared to matched healthy controls. Various protein types involved in diverse molecular functions and cellular processes emphasise the multifaceted pathomechanisms of MSA. These data could contribute to the development of novel disease-modifying treatment strategies for MSA patients. Full article

The relationship between sleep and epilepsy involves complex interactions between thalamocortical circuits, circadian mechanisms, and sleep architecture that fundamentally influence seizure susceptibility and cognitive outcomes. Epileptic activity disrupts essential sleep oscillations, particularly sleep spindles generated by thalamic circuits. Thalamic epileptic spikes actively compete with physiological sleep spindles, impairing memory consolidation and contributing to cognitive dysfunction in epileptic encephalopathy. This disruption explains why patients with epilepsy often experience learning difficulties despite adequate seizure control. Sleep stages show differential seizure susceptibility. REM sleep provides robust protection through enhanced GABAergic inhibition and motor neuron suppression, while non-REM sleep, particularly slow-wave sleep, increases seizure risk. These observations reveal fundamental mechanisms of seizure control within normal brain physiology. Circadian clock genes (BMAL1, CLOCK, PER, CRY) play crucial roles in seizure modulation. Dysregulation of these molecular timekeepers creates permissive conditions for seizure generation while being simultaneously disrupted by epileptic activity, establishing a bidirectional relationship. These mechanistic insights are driving chronobiological therapeutic approaches, including precisely timed antiseizure medications, sleep optimization strategies, and orexin/hypocretin system interventions. This understanding enables a paradigm shift from simple seizure suppression toward targeted restoration of physiological brain rhythms, promising transformative epilepsy management through sleep-informed precision medicine. Full article

Leptin, an adipocyte-derived hormone, plays a central role in the regulation of energy homeostasis by acting on distinct hypothalamic nuclei. This review explores recent advances in our understanding of leptin’s region-specific actions within the arcuate nucleus, ventromedial hypothalamus, dorsomedial hypothalamus, and lateral hypothalamus, highlighting their contributions to appetite regulation, energy expenditure, and neuroendocrine function. In the hypothalamic arcuate nucleus, leptin’s differential regulation of pro-opiomelanocortin and agouti-related peptide/neuropeptide Y neurons is now complemented by the identification of novel leptin-responsive neuronal populations—such as those expressing prepronociceptin, basonuclin 2, and Pirt—as well as a growing array of cellular and molecular modulators, including secreted factors like angiopoietin-like growth factor, zinc-α2-glycoprotein, and spexin, intracellular regulators such as Rap1, growth factor receptor-bound protein 10, and spliced X-box binding protein 1. In the ventromedial hypothalamus, leptin integrates with both peripheral (e.g., cholecystokinin) and central (e.g., pituitary adenylate cyclase-activating polypeptide) signals, while epigenetic mechanisms, such as those mediated by Jumonji domain-containing protein D3, regulate leptin receptor expression and sensitivity. The dorsomedial hypothalamus is increasingly recognized for coordinating leptin’s effects on metabolism, circadian rhythms, and respiration through distinct neuronal populations, including a subset of neurons co-expressing GLP-1 receptors that mediate leptin’s metabolic effects. In the lateral hypothalamus, leptin modulates reward-driven feeding via GABAergic neuronal populations—circuits that are particularly susceptible to disruption following early life trauma. Together, these insights reveal a sophisticated neurobiological framework through which leptin orchestrates systemic physiology. Understanding the heterogeneity of leptin signaling opens new avenues for restoring leptin sensitivity and developing personalized therapeutic strategies to combat obesity and related metabolic disorders. Full article

Nelumbo nucifera (lotus) has long been used in traditional medicine across Asia, and its bioactive alkaloids have recently garnered attention for their neuroprotective properties. This review summarizes the current research on the mechanisms by which lotus-derived alkaloids, particularly neferine, nuciferine, liensinine, and isoliensinine, protect neural tissues. These compounds exhibit a wide range of pharmacological activities, including antioxidant and anti-inflammatory effects, regulation of calcium signaling and ion channels, promotion of neurogenesis, and modulation of key neurotransmitter systems, such as dopaminergic, cholinergic, and GABAergic pathways. Notably, they attenuate tau hyperphosphorylation, reduce oxidative stress-induced neuronal apoptosis, and enhance neurotrophic signaling via BDNF-related pathways. While antioxidant and anti-inflammatory actions are the most extensively studied, emerging evidence also highlights their roles in autophagy modulation and mitochondrial protection. Together, these findings suggest that lotus alkaloids are promising candidates for the prevention and treatment of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases. Further investigation is warranted to explore the synergistic mechanisms and potential clinical applications of these compounds. Full article

Using in vitro models of hypoxia, episodes of short-term hypoxia/reoxygenation, and ischemia-like conditions, we were able to establish different sensitivities of hippocampal neurons to their damaging factors. Using a combination of fluorescence microscopy and immunocytochemistry methods, it was possible to show that GABAergic neurons are the most vulnerable to the damaging effects of hypoxia and ischemia-like conditions, as they have a special metabolism, which is characterized by increased production of reactive oxygen species and nitric oxide. It was shown that long-term hypoxia causes the death of GABAergic neurons due to the induction of a global [Ca²⁺]_i increase, whereas pyramidal neurons are resistant to 30-min hypoxia. Episodes of short-term hypoxia/reoxygenation activate the phenomenon of hypoxic preconditioning in glutamatergic neurons, while this endogenous protective mechanism is absent in GABAergic neurons. Selective activation of PI3K and PKG, combined with NOS inhibition, potentiates the preconditioning effect of hypoxia/reoxygenation in glutamatergic neurons and partially activates this neuroprotective mechanism in GABAergic neurons, as indicated by diminished post-hypoxic NMDA-induced Ca²⁺ transients. These findings suggest that pharmacological intervention can protect GABAergic neuronal populations. The expression of parvalbumin, calbindin, or calretinin in the cytosol of GABAergic neurons contributes to the suppression of the global [Ca²⁺]_i increase during hypoxia/reoxygenation episodes, which correlates with their survival even in the absence of the hypoxic preconditioning phenomenon. Additionally, all three studied calcium-binding proteins showed potential high efficiency in maintaining the bioenergetics of GABAergic neurons during ischemia-like conditions, limiting ROS production by mitochondria and in the cytosol, and reducing nitric oxide formation. In this case, parvalbumin showed the greatest efficiency. Full article

The rhythm of epileptiform activity occurs in various brain injuries (ischemia, stroke, concussion, mechanical damage, AD, PD). The epileptiform rhythm is accompanied by periodic Ca²⁺ pulses, which are necessary for the neurotransmitter release, the repair of damaged connections between neurons, and the growth of new projections. The duration and amplitude of these pulses depend on intracellular calcium-binding proteins. The effect of the synthetic fast calcium buffer BAPTA on the epileptiform activity of neurons induced by the GABA(A)-receptor inhibitor, bicuculline, was investigated in a 14-DIV rat hippocampal culture. In the epileptiform activity mode, neurons periodically synchronously generate action potential (AP) bursts in the form of paroxysmal depolarization shift (PDS) clusters and their corresponding high-amplitude Ca²⁺ pulses. Changes in the paroxysmal activity and Ca²⁺ pulses were recorded continuously for 10–11 min as BAPTA accumulated. It was shown that during BAPTA accumulation, transformation of neuronal patch activity occurs. Moreover, GABAergic and glutamatergic neurons respond differently to the presence of calcium buffer. Experiments were performed on two populations of neurons: a population of GABAergic neurons that responded selectively to ATPA, a calcium-permeable GluK1 kainate receptor agonist, and a population of glutamatergic neurons with a large amplitude of cluster depolarization (greater than −20 mV). These neurons made up the majority of neurons. In the population of GABAergic neurons, during BAPTA accumulation, the amplitude of PDS clusters decreases, which leads to a switch from the PDS mode to the classical burst mode with an increase in the electrical activity of the neuron. In glutamatergic neurons, the duration of PDS clusters decreased during BAPTA accumulation. However, the amplitude changed little. The data obtained showed that endogenous calcium-binding proteins play a significant role in switching the epileptiform rhythm to the recovery rhythm and perform a neuroprotective function by reducing the duration of impulses in excitatory neurons and the amplitude of impulses in inhibitory neurons. Full article

The hypothalamus–pituitary–ovarian (HPO) axis orchestrates reproductive functions through intricate neuroendocrine crosstalk. Here, we integrated single-nucleus RNA sequencing (snRNA-seq) and spatial transcriptomics (ST) to decode the cellular heterogeneity and intercellular communication networks in the reproductive systems of pregnant Mongolian cattle. We retained a total of 6161 high-quality nuclei from the hypothalamus, 14,715 nuclei from the pituitary, and 26,072 nuclei from the ovary, providing a comprehensive cellular atlas across the HPO axis. In the hypothalamus, neurons exhibited synaptic and neuroendocrine specialization, with glutamatergic subtype Glut4 serving as a TGFβ signaling hub to regulate pituitary feedback, while GABAergic GABA1 dominated PRL signaling, likely adapting maternal behavior. Pituitary stem cells dynamically replenished endocrine populations via TGFβ, and lactotrophs formed a PRL–PRLR paracrine network with stem cells, synergizing mammary development. Ovarian luteal cells exhibited steroidogenic specialization and microenvironmental synergy: endothelial cells coregulated TGFβ-driven angiogenesis and immune tolerance, while luteal–stromal PRL–PRLR interactions amplified progesterone synthesis and nutrient support. Granulosa cells (GCs) displayed spatial-functional stratification, with steroidogenic GCs persisting across pseudotime as luteinization precursors, while atretic GCs underwent apoptosis. Spatial mapping revealed GCs’ annular follicular distribution, mediating oocyte–somatic crosstalk, and luteal–endothelial colocalization supporting vascularization. This study unveils pregnancy-specific HPO axis regulation, emphasizing multi-organ crosstalk through TGFβ/PRL pathways and stem cell-driven plasticity, offering insights into reproductive homeostasis and pathologies. Full article

Social anxiety disorder (SAD) is characterized by fear and avoidance of social situations. Considering the reduced availability of conventional therapies, we aimed to improve our understanding of the biological mechanisms in SAD by evaluating gamma-aminobutyric acid (GABA) and other neurometabolites (including glutamate + glutamine/glutamix (Glx), N-acetyl aspartate (NAA), myo-inositol (mI), total choline (tCho), and total creatine (tCr) in the dorsomedial prefrontal cortex/anterior cingulate cortex (dmPFC/ACC), dorsolateral prefrontal cortex (dlPFC), and the insula). In this pilot study, we recruited 26 (age: 25.3 ± 5.0 years; 61.5% female) individuals with SAD and 26 (age: 25.1 ± 4.4 years; 61.5% female) sex-age-matched controls. Using proton magnetic resonance spectroscopy, we found that compared to the controls, GABA+ macromolecular signal (GABA+) in dlPFC (t = 2.63; p = 0.012) and Glx in the insula (Mann–Whitney U = 178.3; p = 0.024) were higher in the participants with SAD. However, no between-group differences were observed in dmPFC/ACC (t = 0.39; p = 0.699). Increased GABA+ in dlPFC could be explained by aberrant GABA transporters. In the insula, increased Glx may be associated with the dysfunction of glutamate transporters or decreased activity of glutamic acid decarboxylase in the GABAergic inhibitory neurons. However, these proposed mechanisms need to be further investigated in SAD. Full article

The GABA_A receptors, through a short-term interaction with a mediator, induce hyperpolarization of the membrane potential (V_m) via the passive influx of chloride ions (Cl⁻) into neurons. The massive (or intense) activation of the GABA_ARs by the agonist could potentially lead to depolarization/excitation of the V_m. Although the ionic mechanisms of GABA_A-mediated depolarization remain incompletely understood, a combination of the outward chloride current and the inward bicarbonate current and the resulting pH shift are the main reasons for this event. The GABA_A responses are determined by the ionic gradients—neuronal pH/bicarbonate homeostasis is maintained by carbonic anhydrase and electroneutral/electrogenic bicarbonate transporters and the chloride level is maintained by secondary active cation–chloride cotransporters. Massive activation can also induce the rundown effect of the receptor function. This rundown effect partly involves phosphorylation, Ca²⁺ and the processes of receptor desensitization. In addition, by various methods (including fluorescence and optical genetic methods), it has been shown that massive activation of GABA_ARs during pathophysiological activity is also associated with an increase in [Cl⁻]_i and a decline in the pH and ATP levels in neurons. Although the relationship between the neuronal changes induced by massive activation of GABAergic signaling and the risk of developing neurodegenerative disease has been extensively studied, the molecular determinants of this process remain somewhat mysterious. The aim of this review is to summarize the data on the relationship between the massive activation of inhibitory signaling and the ionic changes in neurons. The potential role of receptor dysfunction during massive activation and the resulting ionic and metabolic disruption in neurons during the manifestation of network/seizure activity will be considered. Full article

Medulloblastoma (MB) is the most common malignant brain tumor in children and typically arises in the cerebellum, likely due to disruptions in neuronal precursor development. The primary inhibitory neurotransmitter in the central nervous system (CNS), γ-aminobutyric acid (GABA), exerts its effects through GABA_A, GABA_B, and GABA_C receptors. GABA receptor activity regulates the development and function of cerebellar neurons, including glutamatergic cerebellar granule cells (CGCs). Beyond the nervous system, GABA is also a common metabolite in non-neuronal cell types. An increasing body of evidence indicates that GABA can influence cell proliferation, differentiation, and migration in several types of adult solid tumors, including brain cancers. GABA and GABA_A receptor agonists can impair the viability and survival of MB cells, primarily acting on GABA_A receptors containing the α5 subunit. A marked expression of the gene encoding the α5 subunit is found across all MB tumor molecular subgroups, particularly Group 3 MB, which has a poor prognosis. Importantly, high levels of the γ-aminobutyric acid type A receptor subunit α5 (GABRA5) gene are associated with shorter patient overall survival in Group 3 and Group 4 MB. In contrast, high γ-aminobutyric acid type A receptor subunit β1 (GABRB1) gene expression is related to longer survival in all MB subgroups. The GABAergic system may, therefore, regulate MB cell function and tumor progression and influence patient prognosis, and is worthy of further investigation as a biomarker and therapeutic target in MB. Full article