HMGB1 Is a Therapeutic Target and Biomarker in Diazepam-Refractory Status Epilepticus with Wide Time Window

Gardeniae Fructus extract terminates refractory status epilepticus with a wide time window through inhibiting neuroinflammation

BACKGROUND

Status epilepticus (SE) is the most severe epilepsy type and exhibits a high resistance rate to the first-line therapy diazepam (DZP), which terms as refractory SE. Activated neuroinflammation is a key factor in the genesis of refractory SE. Gardeniae Fructus, a commonly used traditional Chinese herbal medicine, has been reported to exhibit anti-neuroinflammatory efficacies.

PURPOSE

In this study we aimed to evaluate the effects of Gardenia extract (GE) in two animal models of refractory SE and explore the mechanism of GE on SE.

METHODS

We identified the main components of GE using LC-MS. The pilocarpine (Salagen Tablet) and kainic acid (KA)-induced refractory SE models were established to evaluate the efficacy of GE. We used NeuN staining to observe the neuroprotective effects of GE. Then we employed network pharmacology to find potential therapeutic targets of GE. We verified the potential therapeutic mechanisms via western blot, immunohistochemistry, in vitro electrophysiological recording and pharmacological means.

RESULTS

We identified thirteen main compounds, and demonstrated that combining GE with DZP could effectively terminate refractory SE induced by pilocarpine or KA, with an extended therapeutic time window of up to 3 h. GE also protected against neuronal injuries caused by refractory SE. Network pharmacology analysis suggested that inflammatory high mobility group box-1 (HMGB1) is a potential therapeutic target of GE. GE could reverse the upregulated expression and translocation of HMGB1 in mice with refractory SE and directly inhibited the enhancement of hippocampal excitatory synaptic transmission mediated by HMGB1 activation. Finally, GE was effective in terminating refractory SE caused by HMGB1 activation; whereas GE could not exhibit superior terminating efficacy when HMGB1 was pharmacologically inhibited.

CONCLUSION

These findings indicated for the first time that GE can terminate refractory SE by inhibiting HMGB1-induced neuroinflammation, highlighting its potential as a promising therapeutic strategy for this neurological emergency.

Improving epilepsy management by targeting P2 × 7 receptor with ROS/electric responsive nanomicelles

BACKGROUND

The intricate pathogenesis of epilepsy, characterized by abnormal neuronal discharges and neuroinflammation, underscores the critical involvement of the adenosine triphosphate (ATP)-P2X purinoceptor 7 (P2 × 7) receptor pathway in inflammation activation. To address this, a reactive oxygen species (ROS)/electric-responsive d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-ferrocene-poloxamer nanomicelle (TFP@A) was engineered to deliver the P2 × 7 receptor antagonist A 438,079, aiming to provide a targeted therapeutic strategy for epilepsy management.

METHODS

The study meticulously designed and characterized TFP@A for precise drug delivery through various techniques including transmission electron microscopy (TEM), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC). Cellular uptake and blood-brain barrier (BBB) permeability were evaluated using fluorescein isothiocyanate (FITC)-labeled TFP@A in vitro and in a brain endothelial cell line (bEnd.3) cell BBB model. In vivo distribution and safety assessments were conducted in an epilepsy mouse model. The impact of TFP@A on epilepsy was investigated through seizure analysis, electroencephalogram (EEG) recordings, and inflammatory pathway assessment.

RESULTS

TFP@A exhibited a robust drug release profile under ROS and electrical stimulation conditions. In vitro studies demonstrated its efficacy in scavenging ROS, reducing oxidative stress, and alleviating cell apoptosis in epilepsy models. Efficient cellular uptake, BBB penetration, and in vivo accumulation in the brain were observed. Notably, TFP@A effectively modulated the P2 × 7 receptor (P2 × 7R)-nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) pathway, inhibiting inflammatory mediators and promoting anti-inflammatory responses.

CONCLUSION

TFP@A loaded with the P2 × 7 receptor antagonist showcases potential therapeutic benefits in suppressing NLRP3 inflammasome activation, mitigating microglial-neuron crosstalk, and ameliorating epilepsy symptoms, positioning it as a promising avenue for targeted epilepsy treatment.

Prediction of Pharmacoresistance in Drug-Naïve Temporal Lobe Epilepsy Using Ictal EEGs Based on Convolutional Neural Network

Approximately 30%-40% of epilepsy patients do not respond well to adequate anti-seizure medications (ASMs), a condition known as pharmacoresistant epilepsy. The management of pharmacoresistant epilepsy remains an intractable issue in the clinic. Its early prediction is important for prevention and diagnosis. However, it still lacks effective predictors and approaches. Here, a classical model of pharmacoresistant temporal lobe epilepsy (TLE) was established to screen pharmacoresistant and pharmaco-responsive individuals by applying phenytoin to amygdaloid-kindled rats. Ictal electroencephalograms (EEGs) recorded before phenytoin treatment were analyzed. Based on ictal EEGs from pharmacoresistant and pharmaco-responsive rats, a convolutional neural network predictive model was constructed to predict pharmacoresistance, and achieved 78% prediction accuracy. We further found the ictal EEGs from pharmacoresistant rats have a lower gamma-band power, which was verified in seizure EEGs from pharmacoresistant TLE patients. Prospectively, therapies targeting the subiculum in those predicted as "pharmacoresistant" individual rats significantly reduced the subsequent occurrence of pharmacoresistance. These results demonstrate a new methodology to predict whether TLE individuals become resistant to ASMs in a classic pharmacoresistant TLE model. This may be of translational importance for the precise management of pharmacoresistant TLE.

Circuit Reorganization of Subicular Cell-Type-Specific Interneurons in Temporal Lobe Epilepsy

The subiculum represents a crucial brain pivot in regulating seizure generalization in temporal lobe epilepsy (TLE), primarily through a synergy of local GABAergic and long-projecting glutamatergic signaling. However, little is known about how subicular GABAergic interneurons are involved in a cell-type-specific way. Here, employing Ca2+ fiber photometry, retrograde monosynaptic viral tracing, and chemogenetics in epilepsy models of both male and female mice, we elucidate circuit reorganization patterns mediated by subicular cell-type-specific interneurons and delineate their functional disparities in seizure modulation in TLE. We reveal distinct functional dynamics of subicular parvalbumin+ and somatostatin+ interneurons during secondary generalized seizure. These interneuron subtypes have their biased circuit organizations in terms of both input and output patterns, which undergo distinct reorganization in chronic epileptic condition. Notably, somatostatin+ interneurons exert more effective feedforward inhibition onto pyramidal neurons compared with parvalbumin+ interneurons, which engenders consistent antiseizure effects in TLE. These findings provide an improved understanding of different subtypes of subicular interneurons in circuit reorganization in TLE and supplement compelling proofs for precise treatment of epilepsy by targeting subicular somatostatin+ interneurons.

Early Polytherapy for Probably Benzodiazepine Refractory Naïve Status Epilepticus (Stage 1 Plus)

Stage 1 Plus is defined here as a naïve, previously untreated, status epilepticus (SE) that is probably refractory to Benzodiazepines (BDZ). These cases include not only prolonged SE as previously proposed by the author (SE lasting > 10 min) but also other cases notoriously associated with BDZ refractoriness such as the absence of prominent motor phenomena and acute etiology (especially primary central nervous system etiology). Interestingly, the absence of prominent motor phenomena as is the case of non convulsive SE might implicitly fall in the category of prolonged SE due to the delay in recognition and treatment. Future studies should help identify other factors associated with BDZ refractoriness, therefore widening the definition of Stage 1 Plus. The appropriate timing for defining prolonged SE may also differ depending on different etiology. Consequently, in future tailored models of SE, the definition of prolonged SE could be enhanced by defining it for a longer duration than Tx, a time point that changes based on different etiologies (x), Tx being much shorter than 10 min in acute etiologies. These cases of naïve probably BDZ refractory SE (Stage 1 Plus) might require a different approach: combined polytherapy from the start. The objective of this review is to provide pathophysiological and pre-clinical evidence, mostly from animal studies, for the different approach of combined polytherapy from the start for those cases of SE falling in the definition of Stage 1 Plus.

CRISPR/Cas9-mediated neuronal deletion of 5-lipoxygenase alleviates deficits in mouse models of epilepsy

INTRODUCTION

Our previous work reveals a critical role of activation of neuronal Alox5 in exacerbating brain injury post seizures. However, whether neuronal Alox5 impacts the pathological process of epilepsy remains unknown.

OBJECTIVES

To prove the feasibility of neuron-specific deletion of Alox5 via CRISPR-Cas9 in the blockade of seizure onset and epileptic progression.

METHODS

Here, we employed a Clustered regularly interspaced short-palindromic repeat-associated proteins 9 system (CRISPR/Cas9) system delivered by adeno-associated virus (AAV) to specifically delete neuronal Alox5 gene in the hippocampus to explore its therapeutic potential in various epilepsy mouse models and possible mechanisms.

RESULTS

Neuronal depletion of Alox5 was successfully achieved in the brain. AAV delivery of single guide RNA of Alox5 in hippocampus resulted in reducing seizure severity, delaying epileptic progression and improving epilepsy-associated neuropsychiatric comorbidities especially anxiety, cognitive deficit and autistic-like behaviors in pilocarpine- and kainic acid-induced temporal lobe epilepsy (TLE) models. In addition, neuronal Alox5 deletion also reversed neuron loss, neurodegeneration, astrogliosis and mossy fiber sprouting in TLE model. Moreover, a battery of tests including analysis of routine blood test, hepatic function, renal function, routine urine test and inflammatory factors demonstrated no noticeable toxic effect, suggesting that Alox5 deletion possesses the satisfactory biosafety. Mechanistically, the anti-epileptic effect of Alox5 deletion might be associated with reduction of glutamate level to restore excitatory/inhibitory balance by reducing CAMKII-mediated phosphorylation of Syn ISer603.

CONCLUSION

Our findings showed the translational potential of AAV-mediated delivery of CRISPR-Cas9 system including neuronal Alox5 gene for an alternative promising therapeutic approach to treat epilepsy.

Septal stimulation attenuates hippocampal seizure with subregion specificity

OBJECTIVE

Deep brain stimulation (DBS) is a promising approach for the treatment of epilepsy. However, the optimal target for DBS and underlying mechanisms are still not clear. Here, we compared the therapeutic effects of DBS on distinct septal subregions, aimed to find the precise targets of septal DBS and related mechanisms for the clinical treatment.

METHODS

Assisted by behavioral test, electroencephalography (EEG) recording and analyzing, selectively neuronal manipulation and immunohistochemistry, we assessed the effects of DBS on the three septal subregions in kainic acid (KA)-induced mouse seizure model.

RESULTS

DBS in the medial septum (MS) not only delayed generalized seizure (GS) development, but reduced the severity; DBS in the vertical diagonal band of Broca (VDB) only reduced the severity of GS, while DBS in the horizontal diagonal band of Broca (HDB) subregion showed no anti-seizure effect. Notably, DBS in the MS much more efficiently decreased abnormal activation of hippocampal neurons. EEG spectrum analysis indicated that DBS in the MS and VDB subregions mainly increased the basal hippocampal low-frequency (delta and theta) rhythm. Furthermore, ablation of cholinergic neurons in the MS and VDB subregions blocked the anti-seizure and EEG-modulating effects of septal DBS, suggesting the seizure-alleviating effect of DBS was dependent on local cholinergic neurons.

SIGNIFICANCE

DBS in the MS and VDB, rather than HDB, attenuates hippocampal seizure by activation of cholinergic neurons-augmented hippocampal delta/theta rhythm. This may be of great therapeutic significance for the clinical treatment of epilepsy with septal DBS.

PLAIN LANGUAGE SUMMARY

The optical target of deep brain stimulation in the septum is still not clear. This study demonstrated that stimulation in the medial septum and vertical diagonal band of Broca subregions, but not the horizontal diagonal band of Broca, could alleviate hippocampal seizure through cholinergic neurons-augmented hippocampal delta/theta rhythm. This study may shed light on the importance of precise regulation of deep brain stimulation therapy in treating epileptic seizures.

Small-molecule caspase-1 inhibitor CZL80 terminates refractory status epilepticus via inhibition of glutamatergic transmission

Status epilepticus (SE), a serious and often life-threatening medical emergency, is characterized by abnormally prolonged seizures. It is not effectively managed by present first-line anti-seizure medications and could readily develop into drug resistance without timely treatment. In this study, we highlight the therapeutic potential of CZL80, a small molecule that inhibits caspase-1, in SE termination and its related mechanisms. We found that delayed treatment of diazepam (0.5 h) easily induces resistance in kainic acid (KA)-induced SE. CZL80 dose-dependently terminated diazepam-resistant SE, extending the therapeutic time window to 3 h following SE, and also protected against neuronal damage. Interestingly, the effect of CZL80 on SE termination was model-dependent, as evidenced by ineffectiveness in the pilocarpine-induced SE. Further, we found that CZL80 did not terminate KA-induced SE in Caspase-1-/- mice but partially terminated SE in IL1R1-/- mice, suggesting the SE termination effect of CZL80 was dependent on the caspase-1, but not entirely through the downstream IL-1β pathway. Furthermore, in vivo calcium fiber photometry revealed that CZL80 completely reversed the neuroinflammation-augmented glutamatergic transmission in SE. Together, our results demonstrate that caspase-1 inhibitor CZL80 terminates diazepam-resistant SE by blocking glutamatergic transmission. This may be of great therapeutic significance for the clinical treatment of refractory SE.

The effect of the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy and its relationship with toxoplasmosis

This study aims to investigate the relationship between toxoplasmosis and this pathway, which may be effective in the formation of epilepsy by acting through the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy. In the study, four different experimental groups were formed by selecting Toxoplasma gondii IgG positive and negative patients with idiopathic epilepsy and healthy controls. Experimental groups were as follows: Group 1: Epilepsy+/Toxo- (E+, T-) (n = 10), Group 2: Epilepsy-/Toxo- (E-, T-) (n = 10), Group 3: Epilepsy-/Toxo+ (E-, T+) (n = 10), Group 4: Epilepsy+/Toxo+ (E+, T+) (n = 10). HMGB1, RAGE, TLR4, TLR1, TLR2, TLR3, IRAK1, IRAK2, IKBKB, IKBKG, BCL3, IL1β, IL10, 1 L8 and TNFα mRNA expression levels in the HMGB/RAGE/TLR4/NF-κB signalling pathway were determined by quantitative simultaneous PCR (qRT-PCR) after collecting blood samples from all patients in the groups. Statistical analysis was performed by one-way ANOVA followed by LSD post-hoc tests, and p < 0.05 was considered to denote statistical significance. The gene expression levels of HMGB1, TLR4, IL10, IL1B, IL8, and TLR2 were significantly higher in the G1 group than in the other groups (p < 0.05). In the G3 group, RAGE and BCL3 gene expression levels were significantly higher than in the other groups (p < 0.05). In the G4 group, however, IRAK2, IKBKB, and IKBKG gene expression levels were significantly higher than in the other groups (p < 0.05). HMGB1, TLR4, IRAK2, IKBKB, IL10, IL1B, IL1B, and IL8 in this signalling pathway are highly expressed in epilepsy patients in G1 and seizures occur with the stimulation of excitatory mechanisms by acting through this pathway. The signalling pathway in epilepsy may be activated by HMGB1, TLR4, and TLR2, which are considered to increase the level of proinflammatory cytokines. In T. gondii, this pathway is activated by RAGE and BCL3.

Research progress on the role of inflammatory mediators in the pathogenesis of epilepsy

Epilepsy is an abnormal neurologic disorder distinguished by the recurrent manifestation of seizures, and the precise underlying mechanisms for its development and progression remain uncertain. In recent years, the hypothesis that inflammatory mediators and corresponding pathways contribute to seizures has been supported by experimental results. The potential involvement of neuroinflammation in the development of epilepsy has garnered growing interest. This review centers attention on the involvement of inflammatory mediators in the emergence and progression of epilepsy within recent years, focusing on both clinical research and animal models, to enhance comprehension of the intricate interplay between brain inflammation and epileptogenesis.

Interleukins in Epilepsy: Friend or Foe

Epilepsy is a chronic neurological disorder with recurrent unprovoked seizures, affecting ~ 65 million worldwide. Evidence in patients with epilepsy and animal models suggests a contribution of neuroinflammation to epileptogenesis and the development of epilepsy. Interleukins (ILs), as one of the major contributors to neuroinflammation, are intensively studied for their association and modulatory effects on ictogenesis and epileptogenesis. ILs are commonly divided into pro- and anti-inflammatory cytokines and therefore are expected to be pathogenic or neuroprotective in epilepsy. However, both protective and destructive effects have been reported for many ILs. This may be due to the complex nature of ILs, and also possibly due to the different disease courses that those ILs are involved in. In this review, we summarize the contributions of different ILs in those processes and provide a current overview of recent research advances, as well as preclinical and clinical studies targeting ILs in the treatment of epilepsy.

Current advances in rodent drug-resistant temporal lobe epilepsy models: Hints from laboratory studies

Anti-seizure drugs (ASDs) are the first choice for the treatment of epilepsy, but there is still one-third of patients with epilepsy (PWEs) who are resistant to two or more appropriately chosen ASDs, named drug-resistant epilepsy (DRE). Temporal lobe epilepsy (TLE), a common type of epilepsy usually associated with hippocampal sclerosis (HS), shares the highest proportion of drug resistance (approximately 70%). In view of the key role of the temporal lobe in memory, emotion, and other physiological functions, patients with drug-resistant temporal lobe epilepsy (DR-TLE) are often accompanied by serious complications, and surgical procedures also yield extra considerations. The exact mechanisms for the genesis of DR-TLE remain unillustrated, which makes it hard to manage patients with DR-TLE in clinical practice. Animal models of DR-TLE play an irreplaceable role in both understanding the mechanism and searching for new therapeutic strategies or drugs. In this review article, we systematically summarized different types of current DR-TLE models, and then recent advances in mechanism investigations obtained in these models were presented, especially with the development of advanced experimental techniques and tools. We are deeply encouraged that novel strategies show great therapeutic potential in those DR-TLE models. Based on the big steps reached from the bench, a new light has been shed on the precise management of DR-TLE.

Neuroinflammation in epileptogenesis: from pathophysiology to therapeutic strategies

Epilepsy is a group of enduring neurological disorder characterized by spontaneous and recurrent seizures with heterogeneous etiology, clinical expression, severity, and prognosis. Growing body of research investigates that epileptic seizures are originated from neuronal synchronized and excessive electrical activity. However, the underlying molecular mechanisms of epileptogenesis have not yet been fully elucidated and 30% of epileptic patients still are resistant to the currently available pharmacological treatments with recurrent seizures throughout life. Over the past two decades years accumulated evidences provide strong support to the hypothesis that neuroinflammation, including microglia and astrocytes activation, a cascade of inflammatory mediator releasing, and peripheral immune cells infiltration from blood into brain, is associated with epileptogenesis. Meanwhile, an increasing body of preclinical researches reveal that the anti-inflammatory therapeutics targeting crucial inflammatory components are effective and promising in the treatment of epilepsy. The aim of the present study is to highlight the current understanding of the potential neuroinflammatory mechanisms in epileptogenesis and the potential therapeutic targets against epileptic seizures.

Investigation of Correlation between Resistance to Diazepam and Expression of Inflammatory Markers in The Peripheral Blood of Patients with Status Epilepticus

OBJECTIVE

This study investigated several inflammatory markers' gene and protein expression in status epilepticus (SE) and their correlation with diazepam resistance.

MATERIALS AND METHODS

Peripheral blood samples were collected from 18 adult patients with SE in Cipto Mangunkusumo Central Hospital, consisting of 12 diazepam-responsive and six diazepam-resistant samples, within 72 hours of the onset of the seizure. We collected baseline demographic and clinical data from each subject. Peripheral blood mononuclear cells (PBMCs) were isolated, cultured, stimulated with lipopolysaccharide (LPS) 1 mg/ml, and harvested for RNA isolation. The RNA was used to determine the expression of Human Mobility Group Box 1 (HMGB1), Interleukin- 6 (IL-6), IL-10, Toll-like Receptor 4 (TLR4), and Glial fibrillary acidic protein (GFAP). In addition, we performed serum protein assay of HMGB1, IL-6, IL-10, TLR4, and GFAP to compare with gene expression.

RESULTS

We found a significant difference between the responsive and resistant groups for serum HMGB1 and IL-6 concentration. The mRNA expression of HMGB1 and IL-6 was significantly higher in LPS-stimulated samples in the responsive but not in the resistant groups. The ratio of IL-6 to IL-10 showed a significant difference between LPS and control in the responsive group. Diazepam response was significantly correlated with seizure duration and serum protein concentration of HMGB1.

CONCLUSION

HMGB1 was highly expressed in the resistant group and strongly correlated with diazepam response, and there was a significant increase in HMGB1 mRNA expression in response to LPS stimulation. These findings suggest that targeting HMGB1 may be a promising therapeutic strategy and that HMGB1 levels could be a valuable biomarker for predicting diazepam resistance in SE.

Neuroinflammation catching nanobubbles for microglia-neuron unit modulation against epilepsy

Epilepsy is a common neurological disease caused by synchronous firing of hyperexcitable neurons. Currently, patients with epilepsy are typically treated with antiseizure medicines that work by interrupting the hyperexcitability or hypersynchrony of localized neurons or by inhibiting excitatory neurotransmission. However, these drugs do not treat the underlying causes of epilepsy, and nearly one-third of patients have seizures that cannot be controlled by these medications. Animal and clinical evidence suggests that inflammation caused by neuronal and non-neuronal cells within the epilepsy lesion could play a central role in seizure disorders. Here we report a gas-filled nanobubble (NB) conjugated with diammonium glycyrrhizinate (DG) drugs and sphingosine-1-phosphate (S1P) molecules (S1P@DG-NBs) on the lipid shell for targeted therapy and real-time ultrasound visualization applications against neuroinflammatory injury. Affinity of S1P@DG-NBs for the S1P receptor endows these NBs with enhanced targeting capability to the neuroinflammatory microenvironment of epilepsy, where the DG drugs modulate endothelium-microglia-neuron inflammation by inhibiting high-mobility group box 1 molecules and downregulating the Toll-like receptor 4 signaling pathway, resulting in anti-inflammatory M2 microglia that exert anti-epilepsy effects. Our results show that this technology can enhance visualization of epileptic brain and deliver drugs with anti-inflammatory and immunomodulatory properties to ameliorate seizures symptoms.

Inflachromene attenuates seizure severity in mouse epilepsy models via inhibiting HMGB1 translocation

Epilepsy is not well controlled by current anti-seizure drugs (ASDs). High mobility group box 1 (HMGB1) is a DNA-binding protein in the nucleus regulating transcriptional activity and maintaining chromatin structure and DNA repair. In epileptic brains, HMGB1 is released by activated glia and neurons, interacting with various receptors like Toll-like receptor 4 (TLR4) and downstream glutamatergic NMDA receptor, thus enhancing neural excitability. But there is a lack of small-molecule drugs targeting the HMGB1-related pathways. In this study we evaluated the therapeutic potential of inflachromene (ICM), an HMGB-targeting small-molecule inhibitor, in mouse epilepsy models. Pentylenetetrazol-, kainic acid- and kindling-induced epilepsy models were established in mice. The mice were pre-treated with ICM (3, 10 mg/kg, i.p.). We showed that ICM pretreatment significantly reduced the severity of epileptic seizures in all the three epilepsy models. ICM (10 mg/kg) exerted the most apparent anti-seizure effect in kainic acid-induced epileptic status (SE) model. By immunohistochemical analysis of brain sections from kainic acid-induced SE mice, we found that kainic acid greatly enhanced HMGB1 translocation in the hippocampus, which was attenuated by ICM pretreatment in subregion- and cell type-dependent manners. Notably, in CA1 region, the seizure focus, ICM pretreatment mainly inhibited HMGB1 translocation in microglia. Furthermore, the anti-seizure effect of ICM was related to HMGB1 targeting, as pre-injection of anti-HMGB1 monoclonal antibody (5 mg/kg, i.p.) blocked the seizure-suppressing effect of ICM in kainic acid-induced SE model. In addition, ICM pretreatment significantly alleviated pyramidal neuronal loss and granule cell dispersion in kainic acid-induced SE model. These results demonstrate that ICM is an HMGB-targeting small molecule with anti-seizure potential, which may help develop a potential drug for treating epilepsy.

Electro-responsive micelle-based universal drug delivery system for on-demand therapy in epilepsy

A universal drug delivery system (DDS) with brain-targeted ability is demanded to enhance antiepileptic therapeutic efficacy and reduce side effects in multiple types of epileptic seizures. In this study, we reported a micelle-based DDS possessing the brain-targeted ability and electro-responsive feature for universal delivery of antiepileptic drugs (AEDs). The system is fabricated by ferrocene (Fc)-conjugated D-a-tocopherol polyethylene glycol succinate and amphiphilic block copolymer, which improve the drug encapsulation of different AEDs. Interestingly, the intrinsic nature of TPGS-Fc including transferrin receptor-mediated transcytosis and efflux pump inhibition endows the system with high permeability across the blood-brain barrier. Based on the hydrophobic-hydrophilic transition of Fc, the micelles can respond to epileptiform discharges and thus release the loaded AEDs. Improved antiepileptic efficacy of the micelles has been demonstrated in acute, continuous, and chronic epilepsy models. In summary, we have developed a universal micelle-based DDS for various AEDs delivery, which provides a promising approach to on-demand therapy of different epileptic seizures.

Melatonin regulates microglial polarization to M2 cell via RhoA/ROCK signaling pathway in epilepsy

BACKGROUND

Melatonin (MEL), an endogenous hormone, has been widely investigated in neurological diseases. Microglia (MG), a resident immunocyte localizing in central nervous system is reported to play important functions in the animal model of temporal lobe epilepsy (TLE). Some evidence showed that MEL influenced activation of MG, but the detailed model of action that MEL plays in remains uncertain.

METHODS

In this study, we established a model of TLE in mice by stereotactic injection of kainic acid (KA). We treated the mice with MEL. Lipopolysaccharide, ROCK2-knockdown (ROCK-KD) and -overexpression (ROCK-OE) of lentivirus-treated cells were used in cell experiments to simulate an in vitro inflammatory model.

RESULTS

The results of electrophysiological tests showed that MEL reduced frequency and severity of seizure. The results of behavioral tests indicated MEL improved cognition, learning, and memory ability. Histological evidences demonstrated a significant reduction of neuronal death in the hippocampus. In vivo study showed that MEL changed the polarization status of MG from a proinflammatory M1 phenotype to an anti-inflammatory M2 phenotype by inversely regulating the RhoA/ROCK signaling pathway. In cytological study, we found that MEL had a significant protective effect in LPS-treated BV-2 cells and ROCK-KD cells, while the protective effect of MEL was significantly attenuated in ROCK-OE cells.

CONCLUSION

MEL played an antiepileptic role in the KA-induced TLE modeling mice both in behavioral and histological levels, and changed MG polarization status by regulating the RhoA/ROCK signaling pathway.

Astrocyte-neuron circuits in epilepsy

The epilepsies are a diverse spectrum of disease states characterized by spontaneous seizures and associated comorbidities. Neuron-focused perspectives have yielded an array of widely used anti-seizure medications and are able to explain some, but not all, of the imbalance of excitation and inhibition which manifests itself as spontaneous seizures. Furthermore, the rate of pharmacoresistant epilepsy remains high despite the regular approval of novel anti-seizure medications. Gaining a more complete understanding of the processes that turn a healthy brain into an epileptic brain (epileptogenesis) as well as the processes which generate individual seizures (ictogenesis) may necessitate broadening our focus to other cell types. As will be detailed in this review, astrocytes augment neuronal activity at the level of individual neurons in the form of gliotransmission and the tripartite synapse. Under normal conditions, astrocytes are essential to the maintenance of blood-brain barrier integrity and remediation of inflammation and oxidative stress, but in epilepsy these functions are impaired. Epilepsy results in disruptions in the way astrocytes relate to each other by gap junctions which has important implications for ion and water homeostasis. In their activated state, astrocytes contribute to imbalances in neuronal excitability due to their decreased capacity to take up and metabolize glutamate and an increased capacity to metabolize adenosine. Furthermore, due to their increased adenosine metabolism, activated astrocytes may contribute to DNA hypermethylation and other epigenetic changes that underly epileptogenesis. Lastly, we will explore the potential explanatory power of these changes in astrocyte function in detail in the specific context of the comorbid occurrence of epilepsy and Alzheimer's disease and the disruption in sleep-wake regulation associated with both conditions.

The role of high mobility group box 1 in neuroinflammatory related diseases

High mobility group box 1 (HMGB1) is a ubiquitous and highly conserved non-histone DNA-binding protein with different biological functions according to its subcellular localization. It is widely believed that HMGB1, which is released into the extracellular space, plays a key role in the inflammatory response. In recent years, numerous studies have shown that the development of various neurological diseases such as epilepsy, Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), cerebrovascular disease and traumatic brain injury (TBI) are inextricably linked to inflammation. We will review the mechanisms of HMGB1 and its receptors in nervous system inflammation to provide a basis for further development of new HMGB1-based therapies.

Meta-analysis of HMGB1 levels in the cerebrospinal fluid and serum of patients with epilepsy

BACKGROUND

Epilepsy pathogenesis and progression are strongly influenced by inflammation. High-mobility group box-1 (HMGB1) is a key proinflammatory factor. The purpose of this study was to quantify and assess the relationship between HMGB1 level and epilepsy.

METHODS

We searched Embase, Web of Science, PubMed, and the Cochrane Library for studies examining the relationship between HMGB1 and epilepsy. Two independent researchers extracted data and assessed quality using the Cochrane Collaboration tool. Data extracted were analyzed using Stata 15 and Review Manager 5.3. The study protocol was registered prospectively at INPLASY, ID: INPLASY2021120029.

RESULTS

A total of 12 studies were eligible for inclusion. After exclusion of one study with reduced robustness, 11 studies were included, with a total of 443 patients and 333 matched controls. Two of the articles included cerebrospinal fluid and serum HMGB1 data, which were distinguished by "a" and "b," respectively. The meta-analysis indicated that in comparison with the control group, the HMGB1 level was higher in epilepsy patients (SMD = 0.56, 95% CI = 0.27-0.85, P = 0.0002). Subgroup analysis of specimen types indicated that both serum HMGB1 and cerebrospinal fluid HMGB1 were higher in epilepsy patients than in the control group, with the increase in cerebrospinal fluid HMGB1 being more obvious. Subgroup analysis of disease types demonstrated that the serum HMGB1 level of epileptic seizure patients (including febrile and nonfebrile seizures) was significantly higher than that of matched controls. However, serum HMGB1 levels did not differ significantly between mild epilepsy patients and severe epilepsy patients. Patient age subgroup analysis showed higher HMGB1 in adolescents with epilepsy. Begg's test did not indicate publication bias.

CONCLUSIONS

This is the first meta-analysis to summarize the association between HMGB1 level and epilepsy. The results of this meta-analysis indicate that epilepsy patients have elevated HMGB1. Large-scale studies with a high level of evidence are needed to reveal the exact relationship between HMGB1 level and epilepsy.

Kainic acid induced hyperexcitability in thalamic reticular nucleus that initiates an inflammatory response through the HMGB1/TLR4 pathway

OBJECTIVE

To explore the relationship between the proinflammatory factor high-mobility group box 1 (HMGB1) and glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in the development of epilepsy.

METHODS

Thalamic reticular nucleus (TRN) slices were treated with kainic acid (KA) to simulate seizures. Action potentials and spontaneous inhibitory postsynaptic currents (sIPSCs) were recorded within TRN slices using whole-cell patch clamp techniques. The translocation of HMGB1 was detected by immunofluorescence. The HMGB1/TLR4 signaling pathway and its downstream inflammatory factors (IL-1β and NF-κB) were detected by RTPCR, Western blot and ELISA.

RESULTS

KA-evoked spikings were observed in TRN slices and blocked by perampanel. sIPSCs in the TRN were enhanced by KA and reduced by perampanel. The translocation of HMGB1 in the TRN was promoted by KA and inhibited by perampanel. The expression of the HMGB1/TLR4 signaling pathway was promoted by KA and suppressed by perampanel.

CONCLUSION

KA induced hyperexcitability activates the HMGB1/TLR4 pathway, which potentially leading to neuroinflammation in epilepsy.

Neuroinflammatory mediators in acquired epilepsy: an update

Epilepsy is a group of chronic neurological disorders that have diverse etiologies but are commonly characterized by spontaneous seizures and behavioral comorbidities. Although the mechanisms underlying the epileptic seizures mostly remain poorly understood and the causes often can be idiopathic, a considerable portion of cases are known as acquired epilepsy. This form of epilepsy is typically associated with prior neurological insults, which lead to the initiation and progression of epileptogenesis, eventually resulting in unprovoked seizures. A convergence of evidence in the past two decades suggests that inflammation within the brain may be a major contributing factor to acquired epileptogenesis. As evidenced in mounting preclinical and human studies, neuroinflammatory processes, such as activation and proliferation of microglia and astrocytes, elevated production of pro-inflammatory cytokines and chemokines, blood-brain barrier breakdown, and upregulation of inflammatory signaling pathways, are commonly observed after seizure-precipitating events. An increased knowledge of these neuroinflammatory processes in the epileptic brain has led to a growing list of inflammatory mediators that can be leveraged as potential targets for new therapies of epilepsy and/or biomarkers that may provide valued information for the diagnosis and prognosis of the otherwise unpredictable seizures. In this review, we mainly focus on the most recent progress in understanding the roles of these inflammatory molecules in acquired epilepsy and highlight the emerging evidence supporting their candidacy as novel molecular targets for new pharmacotherapies of acquired epilepsy and the associated behavioral deficits.

Insight into Drug Resistance in Status Epilepticus: Evidence from Animal Models

Status epilepticus (SE), a condition with abnormally prolonged seizures, is a severe type of epilepsy. At present, SE is not well controlled by clinical treatments. Antiepileptic drugs (AEDs) are the main therapeutic approaches, but they are effective for SE only with a narrow intervening window, and they easily induce resistance. Thus, in this review, we provide an updated summary for an insight into drug-resistant SE, hoping to add to the understanding of the mechanism of refractory SE and the development of active compounds. Firstly, we briefly outline the limitations of current drug treatments for SE by summarizing the extensive experimental literature and clinical data through a search of the PubMed database, and then summarize the common animal models of refractory SE with their advantages and disadvantages. Notably, we also briefly review some of the hypotheses about drug resistance in SE that are well accepted in the field, and furthermore, put forward future perspectives for follow-up research on SE.

GABAkines - Advances in the discovery, development, and commercialization of positive allosteric modulators of GABAA receptors

Positive allosteric modulators of γ-aminobutyric acid-A (GABA_A) receptors or GABAkines have been widely used medicines for over 70 years for anxiety, epilepsy, sleep, and other disorders. Traditional GABAkines like diazepam have safety and tolerability concerns that include sedation, motor-impairment, respiratory depression, tolerance and dependence. Multiple GABAkines have entered clinical development but the issue of side-effects has not been fully solved. The compounds that are presently being developed and commercialized include several neuroactive steroids (an allopregnanolone formulation (brexanolone), an allopregnanolone prodrug (LYT-300), Sage-324, zuranolone, and ganaxolone), the α2/3-preferring GABAkine, KRM-II-81, and the α2/3/5-preferring GABAkine PF-06372865 (darigabat). The neuroactive steroids are in clinical development for post-partum depression, intractable epilepsy, tremor, status epilepticus, and genetic epilepsy disorders. Darigabat is in development for epilepsy and anxiety. The imidazodiazepine, KRM-II-81 is efficacious in animal models for the treatment of epilepsy and post-traumatic epilepsy, acute and chronic pain, as well as anxiety and depression. The efficacy of KRM-II-81 in models of pharmacoresistant epilepsy, preventing the development of seizure sensitization, and in brain tissue of intractable epileptic patients bodes well for improved therapeutics. Medicinal chemistry efforts are also ongoing to identify novel and improved GABAkines. The data document gaps in our understanding of the molecular pharmacology of GABAkines that drive differential pharmacological profiles, but emphasize advancements in the ability to successfully utilize GABA_A receptor potentiation for therapeutic gain in neurology and psychiatry.

Inhibition of Neutrophil Extracellular Traps Formation by Cl-Amidine Alleviates Lipopolysaccharide-Induced Endometritis and Uterine Tissue Damage

Endometritis is a common disease that affects the production in dairy cows and leads to severe losses in the dairy industry. Neutrophil extracellular traps (NETs) formation promotes pathogenic invasions of the lumen of the tissue, leading to inflammatory diseases such as mastitis, pancreatitis, and septic infection. However, research that could show the relationship between NETs and endometritis is scarce. Cl-amidine has been shown to ameliorate the disease squealing and clinical manifestation in various disease models. In this study, we investigated the role of NETs in LPS-triggered endometritis in rats and evaluated the therapeutic efficiency of Cl-amidine. An LPS-induced endometritis model in rats was established and found that the formation of NETs can be detected in the rat's uterine tissues in vivo. In addition, Cl-amidine treatment can inhibit NETs construction in LPS-induced endometritis in rats. Myeloperoxidase (MPO) activity assay indicated that Cl-amidine treatment remarkably alleviated the inflammatory cell infiltrations and attenuated the damage to the uterine tissue. The Western blot results indicated that Cl-amidine decreased the expression of citrullinated Histone H3 (Cit-H3) and high-mobility group box 1 protein (HMGB1) protein in LPS-induced rat endometritis. The ELISA test indicated that Cl-amidine treatment significantly inhibited the expression of the pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. The NETs were determined by Quant-iTTMPicoGreen dsDNA kit®, which indicated that Cl-amidine significantly inhibited the NETs in rat serum. All results showed that Cl-amidine effectively reduced the expression of Cit-H3 and HMGB1 proteins by inhibiting the formation of NETs, thereby attenuating the inflammatory response to LPS-induced endometritis in rats. Hence, Cl-amidine could be a potential candidate for the treatment of endometritis.

Anti-Epileptic Effect of Crocin on Experimental Temporal Lobe Epilepsy in Mice

Temporal lobe epilepsy (TLE) is a common kind of refractory epilepsy. More than 30% TLE patients were multi-drug resistant. Some patients may even develop into status epilepticus (SE) because of failing to control seizures. Thus, one of the avid goals for anti-epileptic drug development is to discover novel potential compounds to treat TLE or even SE. Crocin, an effective component of Crocus sativus L., has been applied in several epileptogenic models to test its anti-epileptic effect. However, it is still controversial and its effect on TLE remains unclear. Therefore, we investigated the effects of crocin on epileptogenesis, generalized seizures (GS) in hippocampal rapid electrical kindling model as well as SE and spotaneous recurrent seizure (SRS) in pilocarpine-induced TLE model in ICR mice in this study. The results showed that seizure stages and cumulative afterdischarge duration were significantly depressed by crocin (20 and 50 mg/kg) during hippocampal rapid kindling acquisition. And crocin (100 mg/kg) significantly reduced the incidence of GS and average seizure stages in fully kindled animals. In pilocarpine-induced TLE model, the latency of SE was significantly prolonged and the mortality of SE was significantly decreased by crocin (100 mg/kg), which can also significantly suppress the number of SRS. The underlying mechanism of crocin may be involved in the protection of neurons, the decrease of tumor necrosis factor-α in the hippocampus and the increase of brain derived neurotrophic factor in the cortex. In conclusion, crocin may be a potential and promising anti-epileptic compound for treatment of TLE.

Ferrostatin-1 obviates seizures and associated cognitive deficits in ferric chloride-induced posttraumatic epilepsy via suppressing ferroptosis

Posttraumatic epilepsy (PTE) is a prevalent complication of brain trauma. Current anti-epileptic drugs available do not have satisfactory response to PTE. It is of desperate need to explore novel therapeutic approaches for curing PTE. Our prior work revealed that ferroptosis, a recently discovered mode of cell death, occurs in rodent model of PTE. In the present study, we aimed to further investigate the effect of ferrostatin-1 (Fer-1), a specific ferroptosis inhibitor, on seizure behavior and cognitive deficit in a mouse model of PTE. The preparation of PTE was performed by stereotaxical injection in the somatosensory cortex region of 50 mM FeCl₃. Seizure activity was assessed via Racine scoring and electroencephalogram analysis. PTE-related cognitive function was evaluated by novel object recognition and Morris water maze tests. Ferroptosis-related indices including glutathione peroxidase (GPx) activity and protein expressions of 4-hydroxynonenal (4-HNE) were detected using a commercial kit and immunofluorescence, respectively. It was found that treatment with Fer-1 significantly exerted protective effects against acute seizure and memory decline, although no evident effect on epileptic progression. Fer-1 also exhibited good tolerability and safety as we observed that it hardly influenced the body weight. Furthermore, it was noted that administration of Fer-1 suppressed ferroptosis-related indices including GPx activity and protein expressions of 4-HNE in hippocampus. These data altogether indicate that Fer-1 has potent therapeutic effects against seizures and cognitive impairment following PTE-induced brain insult. Fer-1 may act as a promising drug for curing PTE patients.

Anti-high mobility group box protein 1 monoclonal antibody downregulating P-glycoprotein as novel epilepsy therapeutics

Epilepsy, a neurological illness, is characterized by recurrent uncontrolled seizures. There are many treatments of options that can be used as the therapy of epilepsy. However, anti-seizure medications as the primary treatment choice for epilepsy show many possible adverse effects and even pharmacoresistance to the therapy. High Mobility Group Box 1 (HMGB1) as an initiator and amplifier of the neuroinflammation is responsible for the onset and progression of epilepsy by overexpressing P-glycoprotein on the blood brain barrier. HMGB1 proteins then activate TLR4 in neurons and astrocytes, in which proinflammatory cytokines are produced. Anti-HMGB1 mAb works by blocking the HMGB1, reducing inflammatory activity in the brain that may affect epileptogenesis. Through the process, anti-HMGB1 mAb reduces the TLR4 activity and other receptors that may involve in promote signal of epilepsy such as RAGE. Several studies have shown that anti-HMGB1 has the potential to inhibit the increase in serum HMGB1 in plasma and brain tissue. Further research is needed to identify the mechanism of the inhibiting of overexpression of P-glycoprotein through anti-HMGB1 mAb.

New advances in pharmacoresistant epilepsy towards precise management-from prognosis to treatments

Epilepsy, one of the most severe neurological diseases, is characterized by abrupt recurrent seizures. Despite great progress in the development of antiseizure drugs (ASDs) based on diverse molecular targets, more than one third of epilepsy patients still show resistance to ASDs, a condition termed pharmacoresistant epilepsy. The management of pharmacoresistant epilepsy involves serious challenges. In the past decade, promising advances have been made in the use of interdisciplinary techniques involving biophysics, bioinformatics, biomaterials and biochemistry, which allow more precise prognosis and development of drug target for pharmacoresistant epilepsy. Notably, novel experimental tools such as viral vector gene delivery, optogenetics and chemogenetics have provided a framework for promising approaches to the precise treatment of pharmacoresistant epilepsy. In this review, historical achievements especially recent advances of the past decade in the prognosis and treatment of pharmacoresistant epilepsy from both clinical and laboratory settings are presented and summarized. We propose that the further development of novel experimental tools at cellular or molecular levels with both temporal and spatial precision are necessary to make improve the management and drug development for pharmacoresistant epilepsy in the clinical arena.

MicroRNAs in the development of resistance to antiseizure drugs and their potential as biomarkers in pharmacoresistant epilepsy

Although many new antiseizure drugs have been developed in the past decade, approximately 30%-40% of patients remain pharmacoresistant. There are no clinical tools or guidelines for predicting therapeutic response in individual patients, leaving them no choice other than to try all antiseizure drugs available as they suffer debilitating seizures with no relief. The discovery of predictive biomarkers and early identification of pharmacoresistant patients is of the highest priority in this group. MicroRNAs (miRNAs), a class of short noncoding RNAs negatively regulating gene expression, have emerged in recent years in epilepsy, following a broader trend of their exploitation as biomarkers of various complex human diseases. We performed a systematic search of the PubMed database for original research articles focused on miRNA expression level profiling in patients with drug-resistant epilepsy or drug-resistant precilinical models and cell cultures. In this review, we summarize 17 publications concerning miRNAs as potential new biomarkers of resistance to antiseizure drugs and their potential role in the development of drug resistance or epilepsy. Although numerous knowledge gaps need to be filled and reviewed, and articles share some study design pitfalls, several miRNAs dysregulated in brain tissue and blood serum were identified independently by more than one paper. These results suggest a unique opportunity for disease monitoring and personalized therapeutic management in the future.

IFN-τ Attenuates LPS-Induced Endometritis by Restraining HMGB1/NF-κB Activation in bEECs

Endometritis is a common inflammatory disease in uterine tissues that leads to animal infertility. Among the causes, Escherichia coli infection is one of the main reasons. Interferon-tau (IFN-τ) is the initial pregnancy signal for ruminant embryos and can induce immune tolerance in humans and other species. However, there are scarce reports on whether IFN-τ has a regulatory effect on endometrial inflammatory damage through HMGB1-NF-κB signalling. The purpose of this study was to investigate the regulatory mechanism of IFN-τ in HMGB1-NF-κB signalling in LPS-induced endometritis. ELISA and qPCR were used to detect the expression of LPS-induced pro-inflammatory cytokines in bovine endometrial epithelial cells (bEECs or BEND) under IFN-τ intervention, and the levels of HMGB1, p-IKK and p-p65 were detected by Western blotting. The nuclear translocation of NF-κB p65 was determined through immunofluorescence. In addition, bEECs were transfected with si-HMGB1 to elucidate the key role of HMGB1 and IFN-τ in the endometrial inflammatory cascade. The results indicated that IFN-τ inhibits the expression of related pro-inflammatory cytokines in an inflammatory injury model of bovine endometrial epithelial cells induced by LPS. Furthermore, experiments have proven that IFN-τ has protective effects on E. coli endotoxin-induced endometritis in mice in vivo. IFN-τ inhibited the HMGB1-NF-κB axis and significantly reduced the secretion of pro-inflammatory cytokines, the expression of HMGB1 protein and the levels of IKK and NF-κB p65 phosphorylation. In summary, our results showed that IFN-τ resists E. coli endotoxin-induced endometritis by attenuating HMGB1/NF-κB signalling.

HMGB1, neuronal excitability and epilepsy

Epilepsy is a common neurological disease caused by synchronous firing of hyperexcitable neurons. Currently, anti-epileptic drugs remain the main choice to control seizure, but 30% of patients are resistant to the drugs, which calls for more research on new promising targets. Neuroinflammation is closely associated with the development of epilepsy. As an important inflammatory factor, high mobility group protein B1 (HMGB1) has shown elevated expression and an increased proportion of translocation from the nucleus to the cytoplasm in patients with epilepsy and in multiple animal models of epilepsy. HMGB1 can act on downstream receptors such as Toll-like receptor 4 and receptor for advanced glycation end products, thereby activating interleukin (IL)-1β and nuclear factor kappa-B (NF-κB), which in turn act with glutamate receptors such as the N-methyl-D-aspartate (NMDA) receptors to aggravate hyperexcitability and epilepsy. The hyperexcitability can in turn stimulate the expression and translocation of HMGB1. Blocking HMGB1 and its downstream signaling pathways may be a direction for antiepileptic drug therapy. Here, we review the changes of HMGB1-related pathway in epileptic brains and its role in the modulation of neuronal excitability and epileptic seizure. Furthermore, we discuss the potentials of HMGB1 as a therapeutic target for epilepsy and provide perspective on future research on the role of HMGB1 signaling in epilepsy.

Anti-High Mobility Group Box-1 Monoclonal Antibody Attenuates Seizure-Induced Cognitive Decline by Suppressing Neuroinflammation in an Adult Zebrafish Model

Epilepsy is a chronic brain disease afflicting around 70 million global population and is characterized by persisting predisposition to generate epileptic seizures. The precise understanding of the etiopathology of seizure generation is still elusive, however, brain inflammation is considered as a major contributor to epileptogenesis. HMGB1 protein being an initiator and crucial contributor of inflammation is known to contribute significantly to seizure generation via activating its principal receptors namely RAGE and TLR4 reflecting a potential therapeutic target. Herein, we evaluated an anti-seizure and memory ameliorating potential of an anti-HMGB1 monoclonal antibody (mAb) (1, 2.5 and 5 mg/kg, I.P.) in a second hit Pentylenetetrazol (PTZ) (80 mg/kg, I.P.) induced seizure model earlier stimulated with Pilocarpine (400 mg/kg, I.P.) in adult zebrafish. Pre-treatment with anti-HMGB1 mAb dose-dependently lowered the second hit PTZ-induced seizure but does not alter the disease progression. Moreover, anti-HMGB1 mAb also attenuated the second hit Pentylenetetrazol induced memory impairment in adult zebrafish as evidenced by an increased inflection ration at 3 and 24 h trail in T-maze test. Besides, decreased level of GABA and an upregulated Glutamate level was observed in the second hit PTZ induced group, which was modulated by pre-treatment with anti-HMGB1 mAb. Inflammatory responses occurred during the progression of seizures as evidenced by upregulated mRNA expression of HMGB1, TLR4, NF-κB, and TNF-α, in a second hit PTZ group, which was in-turn downregulated upon pre-treatment with anti-HMGB1 mAb reflecting its anti-inflammatory potential. Anti-HMGB1 mAb modulates second hit PTZ induced changes in mRNA expression of CREB-1 and NPY. Our findings indicates anti-HMGB1 mAb attenuates second hit PTZ-induced seizures, ameliorates related memory impairment, and downregulates the seizure induced upregulation of inflammatory markers to possibly protect the zebrafish from the incidence of further seizures through via modulation of neuroinflammatory pathway.

Deep brain stimulation in the medial septum attenuates temporal lobe epilepsy via entrainment of hippocampal theta rhythm

Aims

Temporal lobe epilepsy (TLE), often associated with cognitive impairment, is one of the most common types of medically refractory epilepsy. Deep brain stimulation (DBS) shows considerable promise for the treatment of TLE. However, the optimal stimulation targets and parameters of DBS to control seizures and related cognitive impairment are still not fully illustrated.

Methods

In the present study, we evaluated the therapeutic potential of DBS in the medial septum (MS) on seizures and cognitive function in mouse acute and chronic epilepsy models.

Results

We found that DBS in the MS alleviated the severity of seizure activities in both kainic acid‐induced acute seizure model and hippocampal‐kindled epilepsy model. DBS showed antiseizure effects with a wide window of effective stimulation frequencies. The antiseizure effects of DBS were mediated by the hippocampal theta rhythm, as atropine, which reversed the DBS‐induced augmentation of the hippocampal theta oscillation, abolished the antiseizure effects of DBS. Further, in the kainic acid‐induced chronic TLE model, DBS in the MS not only reduced spontaneous seizures, but also improved behavioral performance in novel object recognition.

Conclusion

DBS in the MS is a promising approach to attenuate TLE probably through entrainment of the hippocampal theta rhythm, which may be therapeutically significant for refractory TLE treatment.

High Mobility Group Box-1 and Blood-Brain Barrier Disruption

Increasing evidence suggests that inflammatory responses are involved in the progression of brain injuries induced by a diverse range of insults, including ischemia, hemorrhage, trauma, epilepsy, and degenerative diseases. During the processes of inflammation, disruption of the blood–brain barrier (BBB) may play a critical role in the enhancement of inflammatory responses and may initiate brain damage because the BBB constitutes an interface between the brain parenchyma and the bloodstream containing blood cells and plasma. The BBB has a distinct structure compared with those in peripheral tissues: it is composed of vascular endothelial cells with tight junctions, numerous pericytes surrounding endothelial cells, astrocytic endfeet, and a basement membrane structure. Under physiological conditions, the BBB should function as an important element in the neurovascular unit (NVU). High mobility group box-1 (HMGB1), a nonhistone nuclear protein, is ubiquitously expressed in almost all kinds of cells. HMGB1 plays important roles in the maintenance of chromatin structure, the regulation of transcription activity, and DNA repair in nuclei. On the other hand, HMGB1 is considered to be a representative damage-associated molecular pattern (DAMP) because it is translocated and released extracellularly from different types of brain cells, including neurons and glia, contributing to the pathophysiology of many diseases in the central nervous system (CNS). The regulation of HMGB1 release or the neutralization of extracellular HMGB1 produces beneficial effects on brain injuries induced by ischemia, hemorrhage, trauma, epilepsy, and Alzheimer’s amyloidpathy in animal models and is associated with improvement of the neurological symptoms. In the present review, we focus on the dynamics of HMGB1 translocation in different disease conditions in the CNS and discuss the functional roles of extracellular HMGB1 in BBB disruption and brain inflammation. There might be common as well as distinct inflammatory processes for each CNS disease. This review will provide novel insights toward an improved understanding of a common pathophysiological process of CNS diseases, namely, BBB disruption mediated by HMGB1. It is proposed that HMGB1 might be an excellent target for the treatment of CNS diseases with BBB disruption.

MiR-505 as an anti-inflammatory regulator suppresses HMGB1/NF-κB pathway in lipopolysaccharide-mediated endometritis by targeting HMGB1

Endometritis is characterized by severe inflammation and tissue damage. It is a common clinical disease that causes infertility due to infectious diseases of the reproductive system. MicroRNAs (miRNAs) are the current focus of research on the regulation of the inflammatory process and play a vital role in various inflammatory diseases. The highly conserved miR-505 regulates the mechanism of lipopolysaccharide (LPS) induced endometritis, but the extent to which pro-inflammatory genes are activated remains unclear. The results of this study showed that the expression of miR-505 was significantly down-regulated in mouse endometritis tissue and LPS-stimulated BEND cells. The study also showed that overexpression of miR-505 significantly suppressed the production of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, and this effect was reversed by inhibiting the expression of miR-505. Moreover, miR-505 inhibited the expression of HMGB1 by targeting its 3'-UTR, thereby inhibiting the activation of HMGB1/NF-κB signalling. Taken together, the results of this study further confirmed that miR-505, as an anti-inflammatory agent, regulates the activation of the HMGB1/NF-κB signalling pathway through negative feedback.