Neurochemical Research最新文献

Epilepsy is a common neurological disorder often accompanied by hippocampal myelin damage and impaired differentiation of oligodendrocyte precursor cells (OPCs). This study aimed to investigate the regulatory effects of Saracatinib on myelin regeneration and OPC maturation in a mouse model of epilepsy, as well as its underlying mechanisms, to provide new strategies for the treatment of epilepsy-related myelin damage. Changes in hippocampal myelin structure were observed using Fast Blue staining and transmission electron microscopy. Immunofluorescence was used to detect the number of oligodendrocyte precursor cell (OPCs, PDGFRα) and mature oligodendrocytes (ODCs, MBP+). Cell culture experiments verified the effects of Saracatinib on OPC differentiation, and SwissTargetPrediction and GSEA were used to predict its targets. Western blot and immunofluorescence further validated the role of the NOTCH1 signaling pathway in Saracatinib-mediated OPC differentiation. Saracatinib Reduced the Racine Score, Prolonged Seizure Latency, and Decreased Seizure Duration in an Epileptic Mouse Model. Epileptic model mice exhibited significant hippocampal myelin damage, characterized by thinning of myelin sheaths, reduced myelin quantity, and increased axonal exposure. Saracatinib treatment significantly improved myelin structure, restored myelin thickness and continuity, and alleviated axonal atrophy. Immunofluorescence showed that Saracatinib increased MBP expression and decreased PDGFRα expression, promoting the differentiation of OPCs into ODCs. Bioinformatics analysis and experimental validation demonstrated that Saracatinib promoted OPC maturation by inhibiting the NOTCH1 signaling pathway, and this effect could be reversed by the NOTCH1 agonist JAG1. Saracatinib significantly promotes hippocampal myelin regeneration and OPC maturation in epileptic mice by inhibiting the NOTCH1 signaling pathway, providing a potential molecular target and therapeutic strategy for the treatment of epilepsy-related myelin damage.

Bipolar disorder (BD) is a chronic and prevalent psychiatric disease that has been considered a leading cause of disability among psychiatric conditions. Taking into account that there is yet no satisfactory disease-modifying treatment, we investigated the effect of genistein on ouabain-induced BD in male C57BL/6 mice. Animals were categorized into control, genistein control, ouabain model, lithium (Li)-treated, and genistein-treated groups. BD was induced by bilateral intracerebroventricular injection of 0.625 nmol ouabain. Genistein (10 mg/kg/day) was orally administered for 2 weeks following a single dose of ouabain. Open field test, sucrose preference test, and forced swim test were performed. Na⁺/K⁺-ATPase activity was evaluated through measuring the hippocampal levels of phosphorylated epidermal growth factor receptor, proto-oncogene tyrosine-protein kinase, extracellular signal-regulated kinase, and cAMP response element-binding protein (p-CREB) by western blot analysis. The levels of brain-derived neurotrophic factor (BDNF), serotonin, oxidative stress, and inflammatory markers were quantified by ELISA. The BCL-2-associated X protein (BAX) to B-cell Lymphoma/Leukemia (BCL2) ratio was assessed by qRT-PCR. Genistein reduced manic and anxious behaviors during the manic phase and showed an antidepressant effect during the depression phase, all while maintaining an effective metabolic balance on body weight. Additionally, genistein increased serotonin, p-CREB, and BDNF levels while decreasing inflammation and apoptosis produced by ouabain. Furthermore, genistein restored the normal architecture in both hippocampal and cortical H&E-stained sections. Taken together, genistein was able to activate the Na⁺/K⁺-ATPase signalosome via a multifaceted mode of action, exerting a neuroprotective effect in an animal model of BD, promoting genistein as a therapeutic candidate for BD.

Graphical Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia, marked by cognitive decline and memory loss. Its multifactorial etiology involves genetic, environmental, and cellular factors, with key pathological features including amyloid-beta (Aβ) plaques and tau tangles. Recent studies have highlighted the roles of liquid-liquid phase separation (LLPS) and autophagy in AD onset and progression. LLPS, an emerging biophysical phenomenon, facilitates protein aggregation and may contribute to early disease stages. Dysregulated autophagy results in the accumulation of toxic proteins, such as Aβ and tau, exacerbating neurodegeneration. This review explores the interplay between LLPS and autophagy in AD, a relationship often overlooked in the literature. It examines their biological mechanisms, synergistic effects on AD pathology, and potential therapeutic strategies. Additionally, we discuss the therapeutic potential of both natural and non-natural compounds in modulating LLPS and autophagy. While compounds like curcumin show promise, a comprehensive framework for their targeted use remains under development. This review provides theoretical support for the advancement of more precise AD therapies.

Chronic high-dose ketamine, widely recognized for its rapid antidepressant effects, poses significant risks to brain health, particularly in the hippocampus, a region critical for learning, memory, and emotional regulation. This narrative review aims to elucidate the molecular mechanisms underlying ketamine-induced apoptosis in hippocampal neurons, providing a comprehensive synthesis of current research findings. We examine how chronic exposure to high doses of ketamine disrupts glutamatergic signaling through NMDA receptor antagonism, leading to an imbalance in excitatory neurotransmission that triggers apoptotic pathways. Additionally, we explore the roles of neuroinflammation and oxidative stress in exacerbating neuronal vulnerability, highlighting the interplay between these mechanisms. The review discusses how chronic ketamine use activates glial cells, resulting in the release of pro-inflammatory cytokines and increased oxidative damage, further promoting neuronal cell death. Furthermore, we consider the implications of altered neurotrophic factor signaling and mitochondrial dysfunction in the context of ketamine’s neurotoxic effects. By integrating these molecular pathways, we provide insights into the critical factors contributing to ketamine-induced apoptosis. Finally, we highlight the need for further research to clarify the dose-response relationship, individual variability in treatment outcomes, and potential neuroprotective strategies. Ultimately, this review emphasizes the importance of balancing the therapeutic benefits of ketamine with its associated risks, advocating for a nuanced understanding of its long-term effects on brain health to inform clinical practices and optimize patient care.

Graphical Abstract

This graphical abstract summarizes the key molecular pathways underlying chronic high-dose ketamine-induced apoptosis in hippocampal neurons, as explored in this narrative review. The illustration depicts how ketamine's primary mechanism as an NMDA receptor antagonist initiates a cascade of detrimental events: (1) disruption of glutamatergic signaling homeostasis; (2) activation of microglia and astrocytes, leading to neuroinflammation through pro-inflammatory cytokine release; (3) induction of oxidative stress via reactive oxygen species (ROS) generation; (4) impairment of mitochondrial function, promoting cytochrome c release; and (5) dysregulation of neurotrophic factor signaling (e.g., BDNF). These interconnected pathways ultimately converge to activate caspase-dependent apoptotic cascades, resulting in hippocampal neuronal death. This integrative process highlights the critical balance required between ketamine's rapid antidepressant potential and its neurotoxic risks, emphasizing the need for further research into neuroprotective strategies.

This study aims to investigate the neuroprotective effect of 6-shogaol (6-SH) in rats after cardiopulmonary resuscitation (CPR), and to explore the molecular mechanism by which it regulates the miRNA-26a-5p/DAPK1 to inhibit excessive autophagy and calcium overload. A rat model of cerebral ischemia-reperfusion injury after cardiac arrest and CPR was established by asphyxia. Sham, CPR, and CPR + 6-SH groups were set up. DAPK1 overexpression and miRNA-26a-5p inhibition were also performed. Neurological function was evaluated using the Neurological Deficit Score (NDS). Hematoxylin-eosin staining was used to assess pathological damage in brain tissue. Immunofluorescence was used to observe the expression of autophagy markers. Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot (WB) were used to detect the expression of autophagy- and calcium overload-related genes and proteins. A dual-luciferase reporter assay was conducted to verify the targeting relationship between miRNA-26a-5p and DAPK1. Molecular docking was used to analyze the binding interaction between 6-SH and miRNA-26a-5p. The results show that 6-SH significantly reduces brain injury and improves neurological function after CPR. It decreases the expression of autophagy-related proteins (VPS34, Beclin1, LC3) and the calcium overload marker (NMDAR2B). Further mechanistic studies show that 6-SH inhibits DAPK1 expression and attenuates excessive autophagy and calcium overload. In addition, 6-SH binds to miRNA-26a-5p and upregulates its expression, which in turn suppresses DAPK1. When miRNA-26a-5p is inhibited, the effects of 6-SH on DAPK1, autophagy, and calcium overload are partially reversed. In conclusion, 6-SH attenuates brain injury after CPR by regulating the miRNA-26a-5p/DAPK1 to suppress excessive autophagy and calcium overload.

Cerebral ischemia-reperfusion injury (CIRI) involves oxidative stress, inflammation, and regulated cell death, among which ferroptosis has emerged as a key contributor. However, therapeutic strategies targeting ferroptosis remain limited. This study investigated whether Ciwujianoside C (CC), a triterpenoid saponin from Acanthopanax senticosus, protects against CIRI by modulating ferroptosis via the NNAT/NF-κB pathway. In MCAO/R rats, CC reduced infarct size, improved neurological scores, and ameliorated oxidative stress and ferroptosis markers. In BV2 microglia and HT22 cells (a mouse hippocampal neuronal cell line) subjected to OGD/R, CC enhanced cell viability, decreased iron accumulation, and restored GPX4 and FTH1 expression while inhibiting NF-κB activation. Importantly, NNAT knockdown abolished these protective effects, demonstrating NNAT as a critical mediator. These findings reveal that CC protects against CIRI by suppressing ferroptosis through the NNAT/NF-κB axis, highlighting NNAT as a potential therapeutic target in CIRI.

PAK1, a key regulator of cytoskeletal remodeling, is associated with synaptic plasticity, but its role in epilepsy remains unclear. This study investigated whether PAK1 contributes to epileptogenesis by modulating hippocampal synaptic plasticity via the LIMK signalling pathway. A chronic epilepsy model was induced in mice via the use of pentylenetetrazol (PTZ). LV-PAK1-shRNA was stereotactically injected into the hippocampus to downregulate PAK1. Seizure susceptibility was evaluated through seizure scores and latency to kindling. Western blotting was used to assess the expression of PAK1, LIMK1/2, and phosphorylated LIMK1/2 (p-LIMK1/2). Golgi-Cox staining and transmission electron microscopy were used to analyze dendritic spine density and the number of synaptic vesicles in the CA1 region. Epileptic mice presented increased hippocampal expression of PAK1, LIMK1/2, and p-LIMK1/2. PAK1 knockdown reduced LIMK1/2 and p-LIMK1/2 levels, decreased seizure severity, and delayed epileptogenesis. It also significantly reduced the dendritic spine density and number of synaptic vesicles in CA1 neurons. PAK1 may contribute to epileptogenesis by regulating dendritic spine formation and synaptic vesicle availability via the LIMK pathway, highlighting its potential as a therapeutic target for epilepsy.

Repetitive transcranial magnetism (rTMS) exerts neuroprotective function in the cerebral ischemia/reperfusion (I/R) injury during the early stage. Intermittent theta-burst stimulation (iTBS), a more time-efficient modality of rTMS, improves the efficiency without at least decreasing the efficacy of the therapy. However, little is known about the neuroprotective mechanisms of iTBS. We aimed to investigate the potential regulatory mechanisms by which iTBS attenuates the early stages of nerve injury after I/R in rats. In in vitro experiments, a therapeutic regimen of iTBS was administered to primary cortical neuronal cells. The Cell Counting Kit-8 (CCK-8) assay was then used for determination of cell viability. The expression of autophagy, ferroptosis-related markers was detected by protein immunoblotting. Mitochondrial membrane potential was examined using JC-1, and mitochondrial reactive oxygen species (ROS) production was measured using MitoSOX staining to assess mitochondrial ROS production. In in vivo experiments, rats were stimulated with iTBS or 10 Hz rTMS. Expression of autophagy and ferroptosis-related markers were detected by protein immunoblotting, and the effects of transcranial magnetic stimulation on oxidative stress in rat serum were further investigated. We also measured the motor function of rats by behavioral tests, in addition to observing neuronal cells in the cortex of rats by Nissl staining and HE staining. In this way, we investigated the mechanism of iTBS to attenuate the nerve injury after I/R in rats. The results of in vitro experiments showed that iTBS reduced neuronal cell injury after OGD, increased mitochondrial autophagy, thereby reducing mitochondrial ROS generation, restored the decrease in mitochondrial membrane potential, and attenuated ferroptosis. In in vivo experiments, we compared the effects of two common treatment modalities, iTBS and 10 Hz rTMS, and investigated the mechanism by which magnetic stimulation exerts a protective effect on neuronal cells, demonstrating that it was able to alleviate the nerve damage of I/R by upregulating the TFEB level, and improved the motor coordination and balance ability of rats. In addition, the results showed that the therapeutic effect of iTBS was not inferior to that of 10 Hz rTMS model. In the present study, we compared the effects of these two common therapeutic modalities in in vivo experiments and investigated the mechanism by which magnetic stimulation exerts a protective effect on neurons. In addition, iTBS can reduce the cost per treatment by several times without compromising the therapeutic efficacy, and can be a practical and less costly intervention.

Neuronal cell damage resulting from ischemic and hypoxic injury is a major pathological event in stroke, with ferroptosis increasingly recognized as a contributing mechanism. In this study, we observed that oxygen-glucose deprivation (OGD) triggered ferroptosis in neuronal cells. By screening of naphthoquinone compounds intervening oxidative stress, we have identified phylloquinone (VK1, also known as vitamin K1) as a potent inhibitor of ferroptosis with significant neuroprotective effects. Phylloquinone also alleviated OGD-induced cellular senescence. Mechanistic investigation revealed that Kruppel-like factor 2 (Klf2) is a potential target of phylloquinone and participates in its neuroprotective effects. These findings indicate that phylloquinone protects neurons from OGD-induced injury by inhibiting ferroptosis through the xCT/GPX4 pathway, highlighting its potential as a therapeutic candidate for ischemic neuronal damage.

Graphical Abstract

The catabolism of the proteinogenic amino acid L-proline in mammalian cells is mediated by mitochondrial enzymes that can oxidize proline to provide energy for mitochondrial ATP regeneration. To investigate the potential of astrocytes to consume and metabolize L-proline, we incubated cultured primary rat astrocytes with L-proline in the absence or the presence of other energy substrates and investigated L-proline consumption, cellular ATP content and cell viability. In the absence of glucose, the cells consumed L-proline which allowed the cells to maintain a high cellular ATP level as long as extracellular L-proline was detectable. This L-proline consumption was saturable and followed apparent Michaelis-Menten kinetics with a calculated K_M value of around 320 µM and a V_max value of around 100 nmol/(h x mg). In contrast to L-proline, D-proline was not consumed by the cells and was unable to prevent a cellular ATP loss in starved astrocytes. L-Proline consumption was lowered in a concentration-dependent manner by known inhibitors of proline dehydrogenase. The potential of 1 mM L-proline to maintain a high cellular ATP content in starved astrocytes and to prevent cell death was almost identical to that found for 1 mM glucose and a co-application of both substrates had additive ATP-maintaining effects. The presence of L-proline hardly affected the consumption of glucose, while glucose, glucose-derived lactate as well as other energy substrates severely slowed down the astrocytic L-proline consumption. In addition, application of L-proline prevented the rapid loss in cellular ATP level and the subsequent toxicity induced in glucose-deprived astrocytes in the presence of inhibitors of the mitochondrial uptake of pyruvate and fatty acids. These protective effects of proline were abolished by an inhibitor of proline dehydrogenase. The data presented demonstrate that L-proline is an excellent energy substrate for cultured astrocytes especially for conditions of limited availability of other energy substrates.