STK24 modulates excitatory synaptic transmission in epileptic hippocampal neurons

A Novel Compound QO-83 Alleviates Acute and Chronic Epileptic Seizures in Rodents by Modulating KV7 Channel Activity

AIMS

KV7 channels are promising targets for antiepileptic therapy. However, the classic KV7 channel opener retigabine has been withdrawn due to severe adverse reactions. We developed a novel KV7 channel opener, QO-83, with good chemical stability and blood-brain barrier penetration, and sought to evaluate its KV7-opening activity, antiepileptic effects, and mechanisms of action.

METHODS

We used patch-clamp electrophysiology, electroencephalogram recordings, dynamic simulations, and various epilepsy models to investigate the mechanisms and antiepileptic activity of QO-83.

RESULTS

Compound QO-83 exhibits greater potency at KV7.2/7.3 channels compared to KV7.4 or KV7.5 channels. It shows superior efficacy for KV7.2 with voltage-dependent opening than retigabine, with W236 identified as the key binding site for the KV7.2 channel. QO-83 significantly inhibited epileptiform discharge and influenced hippocampal sEPSC and sIPSC amplitudes. QO-83 has a more effective dose of 1 mg/kg in acute and chronic epilepsy models smaller than that of retigabine (10 mg/kg). The higher potency of QO-83 may be attributed to its greater stability at the KV7.2 binding pocket compared to retigabine.

CONCLUSION

QO-83, as a newly developed Kv7.2 opener, has the advantages of stable properties, strong affinity, and high activity compared with retigabine, and is expected to become a new antiepileptic drug.

Mitochondria-related HSDL2 is a potential biomarker in temporal lobe epilepsy by modulating astrocytic lipid metabolism

Temporal lobe epilepsy (TLE) is the most prevalent type of focal epilepsy in adults. While comprehensive bioinformatics analyses have facilitated the identification of novel biomarkers in animal models, similar efforts are limited for TLE patients. In the current study, a comprehensive analysis using human transcriptomics datasets GSE205661, GSE190451, and GSE186334 was conducted to reveal differentially expressed genes related to mitochondria (Mito-DEGs). Protein-protein interaction (PPI) network and Least Absolute Shrinkage and Selection Operator (LASSO) regression analyses were performed to identify hub genes. Additional GSE127871 and GSE255223 were utilized to establish the association with hippocampal sclerosis (HS) and seizure frequency, respectively. Single-cell RNA analysis, functional investigation, and clinical verification were conducted. Herein, we reported that the Mito-DEGs in human TLE were significantly enriched in metabolic processes. Through PPI and LASSO analysis, HSDL2 was identified as the hub gene, of which diagnostic potential was further confirmed using independent datasets, animal models, and clinical validation. Subsequent single-cell and functional analyses revealed that HSDL2 expression was enriched and upregulated in response to excessive lipid accumulation in astrocytes. Additionally, the diagnostic efficiency of blood HSDL2 was verified in Qilu cohort. Together, our findings highlight the translational potential of HSDL2 as a biomarker and provide a novel therapeutic perspective for human TLE.

Neuronal small extracellular vesicles carrying miR-181c-5p contribute to the pathogenesis of epilepsy by regulating the protein kinase C-δ/glutamate transporter-1 axis in astrocytes

Information exchange between neurons and astrocytes mediated by extracellular vesicles (EVs) is known to play a key role in the pathogenesis of central nervous system diseases. A key driver of epilepsy is the dysregulation of intersynaptic excitatory neurotransmitters mediated by astrocytes. Thus, we investigated the potential association between neuronal EV microRNAs (miRNAs) and astrocyte glutamate uptake ability in epilepsy. Here, we showed that astrocytes were able to engulf epileptogenic neuronal EVs, inducing a significant increase in the glutamate concentration in the extracellular fluid of astrocytes, which was linked to a decrease in glutamate transporter-1 (GLT-1) protein expression. Using sequencing and gene ontology (GO) functional analysis, miR-181c-5p was found to be the most significantly upregulated miRNA in epileptogenic neuronal EVs and was linked to glutamate metabolism. Moreover, we found that neuronal EV-derived miR-181c-5p interacted with protein kinase C-delta (PKCδ), downregulated PKCδ and GLT-1 protein expression and increased glutamate concentrations in astrocytes both in vitro and in vivo. Our findings demonstrated that epileptogenic neuronal EVs carrying miR-181c-5p decrease the glutamate uptake ability of astrocytes, thus promoting susceptibility to epilepsy.

Genetics of psycho-emotional well-being: genome-wide association study and polygenic risk score analysis

Background

Psycho-emotional well-being is essential for living a life of satisfaction and fulfillment. However, depression and anxiety have become the leading mental health issues worldwide, according to the World Health Organization. Both disorders have been linked to stress and other psychological factors. Their genetic basis remains understudied.

Methods

In 2020-2021, the psycho-emotional well-being of 30,063 Russians with no known psychiatric history was assessed using the Hospital Anxiety and Depression Scale (HADS) for general mental health and the HADS subscale A (anxiety) for anxiety. Following the original instructions, an anxiety score of ≥11 points was used as the anxiety threshold. A genome-wide association study was performed to find associations between anxiety and HADS/HADS-A scores using linear and logistic regressions based on HADS/HADS-A scores as binary and continuous variables, respectively. In addition, the links between anxiety, sociodemographic factors (such as age, sex, and employment), lifestyle (such as physical activity, sleep duration, and smoking), and markers of caffeine and alcohol metabolism were analyzed. To assess the risk of anxiety, polygenic risk score modeling was carried out using open-access software and principal component analysis (PCA) to simplify the calculations (ROC AUC = 89.4 ± 2.2% on the test set).

Results

There was a strong positive association between HADS/HADS-A scores and sociodemographic factors and lifestyle. New single-nucleotide polymorphisms (SNPs) with genome-wide significance were discovered, which had not been associated with anxiety or other stress-related conditions but were located in genes previously associated with bipolar disorder, schizophrenia, or emotional instability. The CACNA1C variant rs1205787230 was associated with clinical anxiety (a HADS-A score of ≥11 points). There was an association between anxiety levels (HADS-A scores) and genes involved in the activity of excitatory neurotransmitters: PTPRN2 (rs3857647), DLGAP4 (rs8114927), and STK24 (rs9517326).

Conclusion

Our results suggest that calcium channels and monoamine neurotransmitters, as well as SNPs in genes directly or indirectly affecting neurogenesis and synaptic functions, may be involved in the development of increased anxiety. The role of some non-genetic factors and the clinical significance of physiological markers such as lifestyle were also demonstrated.

Synthesis of Pyrazole-Based Macrocycles Leads to a Highly Selective Inhibitor for MST3

MST1, MST2, MST3, MST4, and YSK1 are conserved members of the mammalian sterile 20-like serine/threonine (MST) family that regulate cellular functions such as proliferation and migration. The MST3 isozyme plays a role in regulating cell growth and apoptosis, and its dysregulation has been linked to high-grade tumors. To date, there are no isoform-selective inhibitors that could be used for validating the role of MST3 in tumorigenesis. We designed a series of 3-aminopyrazole-based macrocycles based on the structure of a promiscuous inhibitor. By varying the moieties targeting the solvent-exposed region and optimizing the linker, macrocycle JA310 (21c) was synthesized. JA310 exhibited high cellular potency for MST3 (EC50 = 106 nM) and excellent kinome-wide selectivity. The crystal structure of the MST3-JA310 complex provided intriguing insights into the binding mode, which is associated with large-scale structural rearrangements. In summary, JA310 demonstrates the utility of macrocyclization for the design of highly selective inhibitors and presents the first chemical probe for MST3.

SIRT3 enhances the protective effect of Xyloketal B on seizure-induced brain injury by regulating AMPK/mTOR signaling-mediated autophagy

Brain damage in children due to seizures is irreversible and has been a major public health concern. The herbal monomer Xyloketal B (Xyl-B) can be used as a neuroprotective drug because of its antioxidant, antiapoptotic, and anti-inflammatory effects but with few adverse effects. In this article, we constructed a rat developmental convulsion model and a primary hippocampal neuronal cell convulsion model, through which we studied hippocampal neuronal morphology and neuronal apoptosis using H&E staining and TUNEL staining, respectively. Moreover, we measured TNF-α, IL-6, and IL-1β inflammatory factor levels using ELISA, MDA, and SOD kits. The expression of SIRT3 in hippocampal tissues was determined by qPCR and Western blotting. The expression of autophagy-related proteins such as LC3, p62, and Beclin-1 was evaluated by Western blotting or immunohistochemistry. The role of SIRT3 and autophagic activity with Xyl-B in convulsive seizure-induced brain injury was investigated by knocking down SIRT3 expression levels. Our results showed that Xyl-B plays a neuroprotective role in convulsive seizure-induced brain injury by increasing SIRT3 expression and activating the autophagy pathway. The regulatory role of SIRT3 in the autophagy pathway with Xyl-B treatment was explored by knocking down SIRT3 expression and inhibiting autophagy. Our results revealed that SIRT3 enhances the protective effect of Xyl-B against postconvulsive brain injury by regulating AMPK/mTOR signaling-mediated autophagy.

Circular RNA SLC8A1 triggers hippocampal neuronal ferroptosis by regulating FUS-mediated ATF3 mRNA stability in epilepsy

BACKGROUND

Epilepsy is a neurological disorder characterized by recurrent seizures and is often unresponsive to current treatment options. Ferroptosis, a recently defined iron-dependent regulated cell death, has been suggested as a potential therapeutic target for epilepsy due to its association with oxidative stress. Additionally, circRNA SLC8A1 (circSLC8A1) has been implicated in various neurological disorders and oxidative stress-related diseases but its involvement in epilepsy progression, particularly in relation to ferroptosis and oxidative stress, remains unclear.

METHODS

qRT-PCR, Western blot, IHC and ELISA assays were employed to validate the relative expression of targeted genes and proteins. The levels of ROS, iron, LOP and GSH were detected by commercial kits. RNA pull-down and RIP assays were employed to detect the interactions among circSLC8A1, FUS and ATF3. A rat epilepsy model was established for further in vivo confirmation.

RESULTS AND CONCLUSION

In this study, we investigated the potential involvement of circSLC8A1 in epilepsy progression and its connection to ferroptosis and oxidative stress. Our findings demonstrate that circSLC8A1 triggers neuronal ferroptosis by stabilizing ATF3 mRNA expression through recruitment with FUS. The induced neuronal ferroptosis contributes to epilepsy progression. These results enhance our understanding of epilepsy pathogenesis and may provide insights for the development of novel therapeutic strategies.

Inhibition of ANXA2 activity attenuates epileptic susceptibility and GluA1 phosphorylation

INTRODUCTION

Annexin A2 (ANXA2) participates in the pathology of a variety of diseases. Nevertheless, the impact of ANXA2 on epilepsy remains to be clarified.

AIMS

Hence, the study aimed at investigating the underlying role of ANXA2 in epilepsy through behavioral, electrophysiological, and pathological analyses.

RESULTS

It was found that ANXA2 was markedly upregulated in the cortical tissues of temporal lobe epilepsy patients (TLE), kainic acid (KA)-induced epilepsy mice, and in a seizure-like model in vitro. ANXA2 silencing in mice suppressed first seizure latency, number of seizures, and seizure duration in behavioral analysis. In addition, abnormal brain discharges were less frequent and shorter in the hippocampal local field potential (LFP) record. Furthermore, the results showed that the frequency of miniature excitatory postsynaptic currents was decreased in ANXA2 knockdown mice, indicating that the excitatory synaptic transmission is reduced. Co-immunoprecipitation (COIP) experiments demonstrated that ANXA2 interacted with the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunit GluA1. Moreover, ANXA2 knockdown decreased GluA1 expression on the cell surface and its phosphorylation onserine 831 and serine 845, related to the decreased phosphorylation levels mediated by protein kinases A and C (PKA and PKC).

CONCLUSIONS

This study covers a previously unknown and key function of ANXA2 in epilepsy. These findings indicate that ANXA2 can regulate excitatory synaptic activity mediated by AMPAR subunit GluA1 to improve seizure activity, which can provide novel insights for the treatment and prevention of epilepsy.

Downregulation of NHE1 expression attenuates apoptosis of primary hippocampal neurons of an epilepsy model through the calpain-1 pathway

OBJECTIVE

Na(+)/H(+) exchanger isoform 1 (NHE1), a membrane protein that regulates intracellular pH, is abundantly expressed in brain tissues. It is associated with pathophysiologies in several brain diseases. The present study aimed to investigate the effects of NHE1 on the apoptosis of primary neurons of an epilepsy model.

METHODS

Primary hippocampal neurons were cultured in an Mg2+-free medium to establish an epilepsy cell model. Designed shNHE1 lentivirus was used to silence NHE1 level in primary neurons. Nonselective pharmacological inhibitor MDL-28170 (20 μmol/L) was used to inhibit calpain-1 protein in neurons treated with Mg2+-free medium. The expression levels of NHE1 and calpain-1, intracellular Ca2+ (Ca2+i) and H+ (H+i) levels, and the expression levels of apoptosis-related proteins Bcl-2 and Bax were detected in neurons. TUNEL staining was performed to determine apoptosis in different groups.

RESULTS

NHE1 expression was increased in primary neurons treated with an Mg2+-free medium, and it was correlated with increased expression of calpain-1 and cell apoptosis. Neurons from the in vitro epilepsy model showed significantly decreased Bcl-2 protein expression and significantly increased Bax protein expression. In the presence of LV-shNHE1 and the calpain-1 inhibitor MDL-28170, the changes in the expression of apoptosis-related proteins Bcl-2 and Bax were blocked in the epileptic model, and the percentage of apoptotic neurons among neurons from the in vitro epilepsy model was significantly decreased. The increase in calpain-1 expression was suppressed by LV-shNHE1; however, the inhibition of calpain-1 did not affect NHE1 expression.

CONCLUSION

These results demonstrate that NHE1 participates in the promotion of neuronal apoptosis of epilepsy model in vitro through the calpain-1 pathway. Downregulation of NHE1 expression could exert a neuroprotective effect on epilepsy.

Persistent Neuroadaptations in the Nucleus Accumbens Core Accompany Incubation of Methamphetamine Craving in Male and Female Rats

Relapse is a major problem in treating methamphetamine use disorder. "Incubation of craving" during abstinence is a rat model for persistence of vulnerability to craving and relapse. While methamphetamine incubation has previously been demonstrated in male and female rats, it has not been demonstrated after withdrawal periods greater than 51 d and most mechanistic work used males. Here, we address both gaps. First, although methamphetamine intake was higher in males during self-administration training (6 h/d × 10 d), incubation was similar in males and females, with "incubated" craving persisting through withdrawal day (WD)100. Second, using whole-cell patch-clamp recordings in medium spiny neurons (MSNs) of the nucleus accumbens (NAc) core, we assessed synaptic levels of calcium-permeable AMPA receptors (CP-AMPARs), as their elevation is required for expression of incubation in males. In both sexes, compared with saline-self-administering controls, CP-AMPAR levels were significantly higher in methamphetamine rats across withdrawal, although this was less pronounced in WD100-135 rats than WD15-35 or WD40-75 methamphetamine rats. We also examined membrane properties and NMDA receptor (NMDAR) transmission. In saline controls, MSNs from males exhibited lower excitability than females. This difference was eliminated after incubation because of increased excitability of MSNs from males. NMDAR transmission did not differ between sexes and was not altered after incubation. In conclusion, incubation persists for longer than previously described and equally persistent CP-AMPAR plasticity in NAc core occurs in both sexes. Thus, abstinence-related synaptic plasticity in NAc is similar in males and females although other methamphetamine-related behaviors and neuroadaptations show differences.

Serine/threonine-protein kinase STK24 induces tumorigenesis by regulating the STAT3/VEGFA signaling pathway

Lung cancer is the most common cause of cancer-related death. Although anti-angiogenesis therapy has been effective in the treatment of nonsmall cell lung cancer (NSCLC), drug-resistance is a common challenge. Therefore, there is a need to develop new therapeutic strategies for NSCLC. Serine/threonine-protein kinase 24 (STK24), also known as MST3, belongs to the germinal center kinase III subfamily, and the biological function of STK24 in NSCLC tumorigenesis and tumor angiogenesis is still unclear. In this study, we demonstrated that STK24 was overexpressed in lung cancer tissues compared with normal lung tissues, and lung cancer patients with higher STK24 expression levels had shorter overall survival time. In addition, our in vitro assays using A549 and H226 cell lines revealed that the STK24 expression level of cancer cells was positively correlated with cancer cells proliferation, migration, invasion, and tumor angiogenesis ability; in vivo assays also demonstrated that silencing of STK24 dramatically inhibited tumor progress and tumor angiogenesis. To investigate a mechanism, we revealed that STK24 positively regulated the signal transducer and activator of transcription 3 (STAT3)/vascular endothelial growth factor A (VEGFA) signaling pathway by inhibiting polyubiquitin-proteasomal-mediated degradation of STAT3. Furthermore, we performed in vivo assays in BALB/c nude mice and in vitro assays to show that STK24-regulated tumor angiogenesis depends on STAT3. These findings deepened our understanding of tumor angiogenesis, and the STK24/STAT3/VEGFA signaling pathway might be a novel therapeutic target for NSCLC treatment.

G-alpha interacting protein interacting protein, C terminus 1 regulates epileptogenesis by increasing the expression of metabotropic glutamate receptor 7

Aims

It has been reported that the G‐alpha interacting protein (GAIP) interacting protein, C terminus 1 (GIPC1/GIPC) engages in vesicular trafficking, receptor transport and expression, and endocytosis. However, its role in epilepsy is unclear. Therefore, in this study, we aimed to explore the role of GIPC1 in epilepsy and its possible underlying mechanism.

Methods

The expression patterns of GIPC1 in patients with temporal lobe epilepsy (TLE) and in mice with kainic acid (KA)‐induced epilepsy were detected. Behavioral video monitoring and hippocampal local field potential (LFP) recordings were carried out to determine the role of GIPC1 in epileptogenesis after overexpression of GIPC1. Coimmunoprecipitation (Co‐IP) assay and high‐resolution immunofluorescence staining were conducted to investigate the relationship between GIPC1 and metabotropic glutamate receptor 7 (mGluR7). In addition, the expression of mGluR7 after overexpression of GIPC1 was measured, and behavioral video monitoring and LFP recordings after antagonism of mGluR7 were performed to explore the possible mechanism mediated by GIPC1.

Results

GIPC1 was downregulated in the brain tissues of patients with TLE and mice with KA‐induced epilepsy. After overexpression of GIPC1, prolonged latency period, decreased epileptic seizures and reduced seizure severity in behavioral analyses, and fewer and shorter abnormal brain discharges in LFP recordings of KA‐induced epileptic mice were observed. The result of the Co‐IP assay showed the interaction between GIPC1 and mGluR7, and the high‐resolution immunofluorescence staining also showed the colocalization of these two proteins. Additionally, along with GIPC1 overexpression, the total and cell membrane expression levels of mGluR7 were also increased. And after antagonism of mGluR7, increased epileptic seizures and aggravated seizure severity in behavioral analyses and more and longer abnormal brain discharges in LFP recordings were observed.

Conclusion

GIPC1 regulates epileptogenesis by interacting with mGluR7 and increasing its expression.

GluN3-Containing NMDA Receptors in the Rat Nucleus Accumbens Core Contribute to Incubation of Cocaine Craving

Cue-induced cocaine craving progressively intensifies (incubates) after withdrawal from cocaine self-administration in rats and humans. In rats, the expression of incubation ultimately depends on Ca²⁺-permeable AMPARs that accumulate in synapses onto medium spiny neurons (MSNs) in the NAc core. However, the delay in their accumulation (∼1 month after drug self-administration ceases) suggests earlier waves of plasticity. This prompted us to conduct the first study of NMDAR transmission in NAc core during incubation, focusing on the GluN3 subunit, which confers atypical properties when incorporated into NMDARs, including insensitivity to Mg²⁺ block and Ca²⁺ impermeability. Whole-cell patch-clamp recordings were conducted in MSNs of adult male rats 1-68 d after discontinuing extended-access saline or cocaine self-administration. NMDAR transmission was enhanced after 5 d of cocaine withdrawal, and this persisted for at least 68 d of withdrawal. The earliest functional alterations were mediated through increased contributions of GluN2B-containing NMDARs, followed by increased contributions of GluN3-containing NMDARs. As predicted by GluN3-NMDAR incorporation, fewer MSN spines exhibited NMDAR-mediated Ca²⁺ entry. GluN3A knockdown in NAc core was sufficient to prevent incubation of craving, consistent with biotinylation studies showing increased GluN3A surface expression, although array tomography studies suggested that adaptations involving GluN3B also occur. Collectively, our data show that a complex cascade of NMDAR and AMPAR plasticity occurs in NAc core, potentially through a homeostatic mechanism, leading to persistent increases in cocaine cue reactivity and relapse vulnerability. This is a remarkable example of experience-dependent glutamatergic plasticity evolving over a protracted window in the adult brain.SIGNIFICANCE STATEMENT "Incubation of craving" is an animal model for the persistence of vulnerability to cue-induced relapse after prolonged drug abstinence. Incubation also occurs in human drug users. AMPAR plasticity in medium spiny neurons (MSNs) of the NAc core is critical for incubation of cocaine craving but occurs only after a delay. Here we found that AMPAR plasticity is preceded by NMDAR plasticity that is essential for incubation and involves GluN3, an atypical NMDAR subunit that markedly alters NMDAR transmission. Together with AMPAR plasticity, this represents profound remodeling of excitatory synaptic transmission onto MSNs. Given the importance of MSNs for translating motivation into action, this plasticity may explain, at least in part, the profound shifts in motivated behavior that characterize addiction.

De Novo Partial 13q22-q34 Trisomy with Typical Neurological and Immunological Findings: A Case Report with New Genetic Insights

The partial trisomy 13q encompasses an extensive variability of phenotypic and radiological findings including leukoencephalopathy and brain malformations such as holoprosencephaly, callosal dysgenesis, hippocampal hypoplasia, olfactory hypoplasia, and vermian hypoplasia. We report for the first time a case of a 23-year-old patient affected by de novo partial 13q22.1q34 trisomy (41.7 Mb, 72,365,975-114,077,122x3) presenting with hemiparesis related to both ischemic and haemorrhagic cerebral lesions compatible with cerebral vasculitis due to a possible combination of genetic and immunological interaction.

STK24 modulates excitatory synaptic transmission in epileptic hippocampal neurons

Introduction

A large amount of literature has indicated that excitatory synaptic transmission plays a crucial role in epilepsy, but the detailed pathogenesis still needs to be clarified.

Methods

In the present study, we used samples from patients with temporal lobe epilepsy, pentylenetetrazole‐kindled mice, and Mg²⁺‐free‐induced epileptic cultured hippocampal neurons to detect the expression pattern of STK24. Then, the whole‐cell recording was carried out after STK24 overexpression in the Mg²⁺‐free‐induced epileptic cultured hippocampal neurons. In addition, coimmunoprecipitation was performed to detect the association between endogenous STK24 and main subunits of NMDARs and AMPARs in the hippocampus of PTZ‐kindled mice.

Results

Here, we reported that STK24 was specifically located in epileptic neurons of human and pentylenetetrazole‐kindled mice. Meanwhile, the expression of STK24 was significantly down‐regulated in these samples which are mentioned above. Besides, we found that the amplitude of miniature excitatory postsynaptic currents was increased in STK24 overexpressed epileptic hippocampal cultured neurons, which means the excitatory synaptic transmission was changed. Moreover, the coimmunoprecipitation, which further supported the previous experiment, indicated an association between STK24 and the subunits of the NMDA receptor.

Conclusion

These findings expand our understanding of how STK24 involved in the excitatory synaptic transmission in epilepsy and lay a foundation for exploring the possibility of STK24 as a drug target.