Dysregulation of REV-ERBα impairs GABAergic function and promotes epileptic seizures in preclinical models

Clinical daily rhythms of seizure in different subtypes of temporal lobe epilepsy

Introduction

The relationship between circadian rhythms and seizures in temporal lobe epilepsy (TLE) has been well recognized, but it remains poorly understood how the interaction between the endogenous clock system and seizures may affect seizure patterns and patient management. This study investigates the circadian rhythm patterns of clinical seizures in TLE, with a focus on different subtypes and clinical variables.

Methods

We retrospectively analyzed the seizure rhythms of patients diagnosed with TLE who were admitted to the video-EEG ward. Patients were categorized based on clinical data, including mesial, lateral, mesio-lateral, and temporal pole types, as well as left, right, and bilateral temporal lobe involvement. Seizure onset times, frequency, and duration were recorded for each patient.

Results

Our findings indicate that TLE patients exhibit notable seizure rhythms, with the peak times of seizure frequency and duration differing across subtypes and age groups. Notably, patients with mesial and mesio-lateral temporal lobe epilepsy showed peak seizure durations between 23:00 and 24:00, while seizure frequency peaked between 19:00 and 20:00 for right temporal lobe patients and between 19:00 and 22:00 for left temporal lobe patients. Additionally, children and adults had distinct seizure rhythms, with children peaking between 21:00 and 24:00, while adults had a peak frequency between 19:00 and 22:00.

Discussion

These findings highlight the variability of seizure rhythms in TLE and underscore the need for personalized treatment strategies that consider circadian factors, potentially leading to better seizure management and therapeutic interventions.

Identification of angiotensin II-responsive circadian clock gene expression in adrenal zona glomerulosa cells and human adrenocortical H295R cells

The mammalian circadian timing system is organized in a hierarchy, with the master clock residing in the suprachiasmatic nucleus (SCN) of the hypothalamus and subsidiary peripheral clocks in peripheral tissues. Because of the diversity of peripheral tissues and cell-types in the body, the existence of autonomous clock and identification of its potential entrainment signals need to be empirically defined on a cell type-by-cell type basis. In this study, we characterized the basic circadian clock properties of the adrenal zona glomerulosa cells, or ZG cells. Using isolated adrenal explants from Per2Luc mice, dissociated ZG cells from Per2-dluc rats, and a related human adrenocortical cell line H295R, we showed that ZG cells possess genetically-encoded, self-sustained and cell-autonomous circadian clock. As to the potential entrainment signals, angiotensin II (Ang II) caused phase-dependent phase-shifts of adrenal ZG cells in cultured slices. Ang II treatment also drove initiation (or reset) of circadian clock gene expression in H295R cells with associated immediate up-regulation of PER1 and E4BP4 mRNA expression. We found that the type I Ang II receptor blocker CV11974, one of the most widely used clinical drugs for hypertensive diseases, caused attenuation of the phase resetting of H295R cells. Our in vitro data provide a basis to understand and argue for the adrenal gland ZG cells as a component of autonomous and entrainable peripheral clocks.

Diurnal dynamics of the Zbtb14 protein in the ventral hippocampus are disrupted in epileptic mice

Our previous in silico data indicated an overrepresentation of the ZF5 motif in the promoters of genes in which circadian oscillations are altered in the ventral hippocampus in the pilocarpine model of temporal lobe epilepsy in mice. In this study, we test the hypothesis that the Zbtb14 protein oscillates in the hippocampus in a diurnal manner and that this oscillation is disrupted by epilepsy. We found that Zbtb14 immunostaining is present in the cytoplasm and cell nuclei. Western blot data indicate that the cytoplasmic and nuclear levels of Zbtb14 protein oscillate, but the phase is shifted. The densities of the Zbtb14-immunopositive cells express diurnal dynamics in the ventral hilus and CA3 but not in the dorsal hilus and CA3, or the somatosensory cortex. In the pilocarpine model of epilepsy, an increase in the level of Zbtb14 protein was found at 11 PM but not at 3 PM compared to controls. Finally, in silico analysis revealed the presence of the ZF5 motif in the promoters of 21 out of 24 genes down-regulated by epileptiform discharges in vitro, many of which are involved in neuronal plasticity. Our data suggest that Zbtb14 may be involved in the diurnal dynamic of seizure regulation or brain response to seizure rhythmicity.

Zingerone alleviates inflammatory pain by reducing the intrinsic excitability of anterior cingulate cortex neurons in a mice model

Background

Zingiber officinale Roscoe has been shown to possess analgesic properties. Zingerone (ZO), a bioactive compound derived from Zingiber officinale Roscoe, exhibits a range of pharmacological effects, including anti-inflammatory, anti-cancer, antioxidant, antibacterial, and anti-apoptotic activities. However, the analgesic properties of zingerone remain unclear.

Methods

Complete Freund's adjuvant (CFA) was administered to the left hind paw of C57BL/6 mice to induce a model of inflammatory pain. The analgesic effects of zingerone were assessed using the Von Frey and Hargreaves tests. In vivo fiber photometry and whole-cell patch clamp techniques were employed to investigate the potential mechanisms.

Results

Both acute and long-term treatment with zingerone resulted in a significant increase in mechanical and thermal pain thresholds in mice experiencing CFA-induced inflammatory pain. Mechanical stimulation led to a pronounced increase in calcium levels within the anterior cingulate cortex (ACC) neurons of the inflammatory pain model, which was alleviated by zingerone administration. Furthermore, zingerone was found to modify synaptic transmission to ACC neurons and decrease their intrinsic excitability by prolonging the refractory period of these neurons.

Conclusion

Zingerone demonstrates potential for alleviating CFA-induced inflammatory pain by reducing the intrinsic excitability of ACC neurons in a mouse model.

The hidden rhythms of epilepsy: exploring biological clocks and epileptic seizure dynamics

Epilepsy, characterized by recurrent seizures, is influenced by biological rhythms, such as circadian, seasonal, and menstrual cycles. These rhythms affect the frequency, severity, and timing of seizures, although the precise mechanisms underlying these associations remain unclear. This review examines the role of biological clocks, particularly the core circadian genes Bmal1, Clock, Per, and Cry, in regulating neuronal excitability and epilepsy susceptibility. We explore how the sleep-wake cycle, particularly non-rapid eye movement sleep, increases the risk of seizures, and discuss the circadian modulation of neurotransmitters like gamma-aminobutyric acid and glutamate. We explore clinical implications, including chronotherapy which refers to the practice of timing medical treatments to align with the body's natural biological rhythms, such as the circadian rhythm. Chronotherapy aligns anti-seizure medication administration with biological rhythms. We also discuss rhythm-based neuromodulation strategies, such as adaptive deep brain stimulation, which may dynamically change stimulation in response to predicted seizures in patients, provide additional therapeutic options. This review emphasizes the potential of integrating biological rhythm analysis into personalized epilepsy management, offering novel approaches to optimize treatment and improve patient outcomes. Future research should focus on understanding individual variability in seizure rhythms and harnessing technological innovations to enhance seizure prediction, precision treatment, and long-term management.

Rhythmic astrocytic GABA production synchronizes neuronal circadian timekeeping in the suprachiasmatic nucleus

Astrocytes of the suprachiasmatic nucleus (SCN) can regulate sleep-wake cycles in mammals. However, the nature of the information provided by astrocytes to control circadian patterns of behavior is unclear. Neuronal circadian activity across the SCN is organized into spatiotemporal waves that govern seasonal adaptations and timely engagement of behavioral outputs. Here, we show that astrocytes across the mouse SCN exhibit instead a highly uniform, pulse-like nighttime activity. We find that rhythmic astrocytic GABA production via polyamine degradation provides an inhibitory nighttime tone required for SCN circuit synchrony, thereby acting as an internal astrocyte zeitgeber (or "astrozeit"). We further identify synaptic GABA and astrocytic GABA as two key players underpinning coherent spatiotemporal circadian patterns of SCN neuronal activity. In describing a new mechanism by which astrocytes contribute to circadian timekeeping, our work provides a general blueprint for understanding how astrocytes encode temporal information underlying complex behaviors in mammals.

Effect of NR1D1 on the proliferation and differentiation of yak skeletal muscle satellite cells

The severe conditions at high altitudes, where yaks inhabit, contribute to delayed muscular growth and compromised tenderness of their muscle tissue. Myosatellite cells are responsible for the growth and regeneration of skeletal muscle after birth and have the potential to proliferate and differentiate, its development is closely related to meat quality, and the nuclear receptor gene NR1D1 is involved in muscle formation and skeletal muscle regulation. Therefore, in order to understand the effect of NR1D1 on muscle satellite cells, we identified the mRNA expression levels of marker genes specifically expressed in muscle satellite cells at different stages to determine the type of cells isolated. Eventually, we successfully constructed a primary cell line of yak muscle satellite cells. Then we constructed NR1D1 overexpression vector and interference RNA, and introduced them into isolated yak skeletal muscle satellite cells. We performed qPCR, CCK8, and fluorescence-specific to detect the expression of genes or abundance of proteins as markers of cell proliferation and differentiation. Compared with those in the control group, the expression levels of proliferation marker genes KI-67, CYCLIND1, and CYCLINA were significantly inhibited after NR1D1 overexpression, which was also supported by the CCK-8 test, whereas differentiation marker genes MYOD, MYOG, and MYF5 were significantly inhibited. Fluorescence-specific staining showed that KI-67 protein abundance and the number of microfilaments both decreased, while the opposite trend was observed after NR1D1 interference. In conclusion, we confirmed that NR1D1 inhibited the proliferation and differentiation of yak skeletal muscle satellite cells, which provides a theoretical basis for further research on the effect of NR1D1 on improving meat quality traits and meat production performance of yaks.

Timing Mechanisms for Circadian Seizures

For centuries, epileptic seizures have been noticed to recur with temporal regularity, suggesting that an underlying biological rhythm may play a crucial role in their timing. In this review, we propose to adopt the framework of chronobiology to study the circadian timing of seizures. We first review observations made on seizure timing in patients with epilepsy and animal models of the disorder. We then present the existing chronobiology paradigm to disentangle intertwined circadian and sleep-wake timing mechanisms. In the light of this framework, we review the existing evidence for specific timing mechanisms in specific epilepsy syndromes and highlight that current knowledge is far from sufficient. We propose that individual seizure chronotypes may result from an interplay between independent timing mechanisms. We conclude with a research agenda to help solve the urgency of ticking seizures.

Ticking Brain: Circadian Rhythm as a New Target for Cerebroprotection

Circadian rhythm is a master process observed in nearly every type of cell throughout the body, and it macroscopically regulates daily physiology. Recent clinical trials have revealed the effects of circadian variation on the incidence, pathophysiological processes, and prognosis of acute ischemic stroke. Furthermore, core clock genes, the cell-autonomous pacemakers of the circadian rhythm, affect the neurovascular unit-composing cells in a nonparallel manner after the same pathophysiological processes of ischemia/reperfusion. In this review, we discuss the influence of circadian rhythms and clock genes on each type of neurovascular unit cell in the pathophysiological processes of acute ischemic stroke.

The Role of Circadian Rhythm in Neurological Diseases: A Translational Perspective

Intrinsic biological clocks drive the circadian rhythm, which coordinates the physiological and pathophysiological processes in the body. Recently, a bidirectional relationship between circadian rhythms and several neurological diseases has been reported. Neurological diseases can lead to the disruption of circadian homeostasis, thereby increasing disease severity. Therefore, optimizing the current treatments through circadian-based approaches, including adjusted dosing, changing lifestyle, and targeted interventions, offer a promising opportunity for better clinical outcomes and precision medicine. In this review, we provide detailed implications of the circadian rhythm in neurological diseases through bench-to-bedside approaches. Furthermore, based on the unsatisfactory clinical outcomes, we critically discuss the potential of circadian-based interventions, which may encourage more studies in this discipline, with the hope of improving treatment efficacy in neurological diseases.

Targeting Circadian Protein Rev-erbα to Alleviate Inflammation, Oxidative Stress, and Enhance Functional Recovery Following Brain Trauma

Traumatic brain injury (TBI) is a significant cause of morbidity and mortality worldwide, and its pathophysiology is characterized by oxidative stress and inflammation. Despite extensive research, effective treatments for TBI remain elusive. Recent studies highlighted the critical interplay between TBI and circadian rhythms, but the detailed regulation remains largely unknown. Motivated by the observed sustained decrease in Rev-erbα after TBI, we aimed to understand the critical role of Rev-erbα in the pathophysiology of TBI and determine its feasibility as a therapeutic target. Using a mouse model of TBI, we observed that TBI significantly downregulates Rev-erbα levels, exacerbating inflammatory and oxidative stress pathways. The regulation of Rev-erbα with either the pharmacological activator or inhibitor bidirectionally modulated inflammatory and oxidative events, which in turn influenced neurobehavioral outcomes, highlighting the protein's protective role. Mechanistically, Rev-erbα influences the expression of key oxidative stress and inflammatory regulatory genes. A reduction in Rev-erbα following TBI likely contributes to increased oxidative damage and inflammation, creating a detrimental environment for neuronal survival and recovery which could be reversed via the pharmacological activation of Rev-erbα. Our findings highlight the therapeutic potential of targeting Rev-erbα to mitigate TBI-induced damage and improve outcomes, especially in TBI-susceptible populations with disrupted circadian regulation.

Temporal changes in mouse hippocampus transcriptome after pilocarpine-induced seizures

Introduction

Status epilepticus (SE) is a seizure lasting more than 5 min that can have lethal consequences or lead to various neurological disorders, including epilepsy. Using a pilocarpine-induced SE model in mice we investigated temporal changes in the hippocampal transcriptome.

Methods

We performed mRNA-seq and microRNA-seq analyses at various times after drug treatment.

Results

At 1 h after the start of seizures, hippocampal cells upregulated transcription of immediate early genes and genes involved in the IGF-1, ERK/MAPK and RNA-PolII/transcription pathways. At 8 h, we observed changes in the expression of genes associated with oxidative stress, overall transcription downregulation, particularly for genes related to mitochondrial structure and function, initiation of a stress response through regulation of ribosome and translation/EIF2 signaling, and upregulation of an inflammatory response. During the middle of the latent period, 36 h, we identified upregulation of membrane components, cholesterol synthesis enzymes, channels, and extracellular matrix (ECM), as well as an increased inflammatory response. At the end of the latent period, 120 h, most changes in expression were in genes involved in ion transport, membrane channels, and synapses. Notably, we also elucidated the involvement of novel pathways, such as cholesterol biosynthesis pathways, iron/BMP/ferroptosis pathways, and circadian rhythms signaling in SE and epileptogenesis.

Discussion

These temporal changes in metabolic reactions indicate an immediate response to injury followed by recovery and regeneration. CREB was identified as the main upstream regulator. Overall, our data provide new insights into molecular functions and cellular processes involved at different stages of seizures and offer potential avenues for effective therapeutic strategies.

Mechanism of NLRP3 Inflammasome in Epilepsy and Related Therapeutic Agents

Epilepsy is one of the most widespread and complex diseases in the central nervous system (CNS), affecting approximately 65 million people globally, an important factor resulting in neurological disability-adjusted life year (DALY) and progressive cognitive dysfunction. Medication is the most essential treatment. The currently used drugs have shown drug resistance in some patients and only control symptoms; the development of novel and more efficacious pharmacotherapy is imminent. Increasing evidence suggests neuroinflammation is involved in the occurrence and development of epilepsy, and high expression of NLRP3 inflammasome has been observed in the temporal lobe epilepsy (TLE) brain tissue of patients and animal models. The inflammasome is a crucial cause of neuroinflammation by activating IL-1β and IL-18. Many preclinical studies have confirmed that regulating NLRP3 inflammasome pathway can prevent the development of epilepsy, reduce the severity of epilepsy, and play a neuroprotective role. Therefore, regulating NLRP3 inflammasome could be a potential target for epilepsy treatment. In summary, this review describes the priming and activation of inflammasome and its biological function in the progression of epilepsy. In addition, we reviewes the current pharmacological researches for epilepsy based on the regulation of NLRP3 inflammasome, aiming to provide a basis and reference for developing novel antiepileptic drugs.

Clock knockout in inhibitory neurons reduces predisposition to epilepsy and influences anxiety-like behaviors in mice

Epilepsy is a brain disorder affecting up to 1 in 26 individuals. Despite its clinical importance, the molecular mechanisms of epileptogenesis are still far from clarified. Our previous study showed that disruption of Clock in excitatory neurons alters cortical circuits and leads to generation of focal epilepsy. In this study, a GAD-Cre;Clockflox/flox mouse line with conditional Clock gene knockout in inhibitory neurons was established. We observed that seizure latency was prolonged, the severity and mortality of pilocarpine-induced seizure were significantly reduced, and memory was improved in GAD-Cre;Clockflox/flox mice. We hypothesize that mice with CLOCK knockout in inhibitory neurons have increased threshold for seizure, opposite from mice with CLOCK knockout in excitatory neurons. Further investigation showed Clock knockout in inhibitory neurons upregulated the basal protein level of ARC, a synaptic plasticity-associated immediate-early gene product, likely through the BDNF-ERK pathway. Altered basal levels of ARC may play an important role in epileptogenesis after Clock deletion in inhibitory neurons. Although sEPSCs and intrinsic properties of layer 5 pyramidal neurons in the somatosensory cortex exhibit no changes, the spine density increased in apical dendrite of pyramidal neurons in CLOCK knockout group. Our results suggest an underlying mechanism by which the circadian protein CLOCK in inhibitory neurons participates in neuronal activity and regulates the predisposition to epilepsy.

PTZ-kindled rat model; evaluation of seizure, hippocampal EGR-1, and Rev-erbα gene regulation, behavioral analysis, and antioxidant capacity of Gum Arabic

BACKGROUND

Epilepsy is a neurological disease characterized by recurrent seizures, hyperexcitable neurons and various behavioral comorbidities. The electrical charge during seizures depletes the antioxidant defense mechanism in the epileptic brain and increases the oxidative burden. Natural antioxidant compounds are potential therapeutics in the treatment of two major pathologies of epilepsy with their anticonvulsant and anxiolytic effects and can modulate these targets. Gum Arabic is one of the natural plant polysaccharides that is non-toxic and biodegradable.

METHODS AND RESULTS

A total of 30 Wistar albino male rats (8-12 weeks, 350-500 g), were randomly divided into 5 groups with 6 animals in each group: 1-Control, 2-Sham (Phosphate buffer saline (PBS)), 3-PTZ, 4-Gum Arabic, 5-PTZ + Gum Arabic. PTZ was administered i.p at 35 mg/kg/day for 11 days. After 48 h, the injection was completed with 75 mg/kg PTZ. Locomotor activity, immobilization, rearing, grooming, eating, and drinking behaviors were recorded with the LABORAS behavior system for 30 min after kindling. Animals were treated with Gum Arabic (2 mg/kg/day, oral gavage) for 10 days. At the end of the period, animal behavior was recorded again. Then the hippocampus tissues were removed. Oxidative parameters (TAS and TOS), early growth response 1 (EGR1) and nuclear receptor subfamily 1 group D member 1 (Rev-erbα) gene expressions and behaviors were analyzed.

CONCLUSION

Gum Arabic increased TAS levels (P = 0.000), decreased TOS levels (P = 0.000), and thus exhibited antioxidant properties by reducing oxidative stress burden. EGR1, which was upregulated in the seizure group, was downregulated after treatment (P = 0.000), and Rev-erbα was downregulated in seizure and upregulated after treatment (P = 0.000). Gum arabic may be an antiepileptic and anxiolytic therapeutic in improving epileptic seizures by reducing oxidative stress burden through EGR1 and Rev-erbα.0.

Trends in the Utilization of Surgical Modalities for the Treatment of Drug-Resistant Epilepsy: A Comprehensive 10-Year Analysis Using the National Inpatient Sample

BACKGROUND AND OBJECTIVES

Epilepsy is considered one of the most prevalent and severe chronic neurological disorders worldwide. Our study aims to analyze the national trends in different treatment modalities for individuals with drug-resistant epilepsy and investigate the outcomes associated with these procedural trends in the United States.

METHODS

Using the National Inpatient Sample database from 2010 to 2020, patients with drug-resistant focal epilepsy who underwent laser interstitial thermal therapy (LITT), open surgical resection, vagus nerve stimulation (VNS), or responsive neurostimulation (RNS) were identified. Trend analysis was performed using piecewise joinpoint regression. Propensity score matching was used to compare outcomes between 10 years prepandemic before 2020 and the first peak of the COVID-19 pandemic.

RESULTS

This study analyzed a total of 33 969 patients with a diagnosis of drug-resistant epilepsy, with 3343 patients receiving surgical resection (78%), VNS (8.21%), RNS (8%), and LITT (6%). Between 2010 and 2020, there was an increase in the use of invasive electroencephalography monitoring for seizure zone localization (P = .003). There was an increase in the use of LITT and RNS (P < .001), while the use of surgical resection and VNS decreased over time (P < .001). Most of these patients (89%) were treated during the pre-COVID pandemic era (2010-2019), while a minority (11%) underwent treatment during the COVID pandemic (2020). After propensity score matching, the rate of pulmonary complications, postprocedural hematoma formation, and mortality were slightly higher during the pandemic compared with the prepandemic period (P = .045, P = .033, and P = .026, respectively).

CONCLUSION

This study indicates a relative decrease in the use of surgical resections, as a treatment for drug-resistant focal epilepsy. By contrast, newer, minimally invasive surgical approaches including LITT and RNS showed gradual increases in usage.

Targeting NR1D1 in organ injury: challenges and prospects

Nuclear receptor subfamily 1, group D, member 1 (NR1D1, also known as REV-ERBα) belongs to the nuclear receptor (NR) family, and is a heme-binding component of the circadian clock that consolidates circadian oscillators. In addition to repressing the transcription of multiple clock genes associated with circadian rhythms, NR1D1 has a wide range of downstream target genes that are intimately involved in many physiopathological processes, including autophagy, immunity, inflammation, metabolism and aging in multiple organs. This review focuses on the pivotal role of NR1D1 as a key transcription factor in the gene regulatory network, with particular emphasis on the milestones of the latest discoveries of NR1D1 ligands. NR1D1 is considered as a promising drug target for treating diverse diseases and may contribute to research on innovative biomarkers and therapeutic targets for organ injury-related diseases. Further research on NR1D1 ligands in prospective human trials may pave the way for their clinical application in many organ injury-related disorders.

Role of circadian clock in the chronoefficacy and chronotoxicity of clopidogrel

BACKGROUND AND PURPOSE

The role of circadian locomotor output cycles kaput (CLOCK) in regulating drug chronoefficacy and chronotoxicity remains elusive. Here, we aimed to uncover the impact of CLOCK and dosing time on clopidogrel efficacy and toxicity.

EXPERIMENTAL APPROACH

The antiplatelet effect, toxicity and pharmacokinetics experiments were conducted with Clock-/- mice and wild-type mice, after gavage administration of clopidogrel at different circadian time points. The expression levels of drug-metabolizing enzymes were determined by quantitative polymerase chain reaction (qPCR) and western blotting. Transcriptional gene regulation was investigated using luciferase reporter and chromatin immunoprecipitation assays.

KEY RESULTS

The antiplatelet effect and toxicity of clopidogrel in wild-type mice showed a dosing time-dependent variation. Clock ablation reduced the antiplatelet effect of clopidogrel, but increased clopidogrel-induced hepatotoxicity, with attenuated rhythms of clopidogrel active metabolite (Clop-AM) and clopidogrel, respectively. We found that Clock regulated the diurnal variation of Clop-AM formation by modulating the rhythmic expression of CYP1A2 and CYP3A1, and altered clopidogrel chronopharmacokinetics by regulation of CES1D expression. Mechanistic studies revealed that CLOCK activated Cyp1a2 and Ces1d transcription by directly binding to the enhancer box (E-box) elements in their promoters, and promoted Cyp3a11 transcription through enhancing the transactivation activity of albumin D-site-binding protein (DBP) and thyrotroph embryonic factor (TEF).

CONCLUSIONS AND IMPLICATIONS

CLOCK regulates the diurnal rhythmicity in clopidogrel efficacy and toxicity through regulation of CYP1A2, CYP3A11 and CES1D expression. These findings may contribute to optimizing dosing schedules for clopidogrel and may deepen understanding of the circadian clock and chronopharmacology.

Biological rhythms and epilepsy treatment

Approximately one-third of patients with epilepsy are drug-refractory, necessitating novel treatment approaches. Chronopharmacology, which adjusts pharmacological treatment to physiological variations in seizure susceptibility and drug responsiveness, offers a promising strategy to enhance efficacy and tolerance. This narrative review provides an overview of the biological foundations for rhythms in seizure activity, clinical implications of seizure patterns through case reports, and the potential of chronopharmacological strategies to improve treatment. Biological rhythms, including circadian and infradian rhythms, play an important role in epilepsy. Understanding seizure patterns may help individualize treatment decisions and optimize therapeutic outcomes. Altering drug concentrations based on seizure risk periods, adjusting administration times, and exploring hormone therapy are potential strategies. Large-scale randomized controlled trials are needed to evaluate the efficacy and safety of differential and intermittent treatment approaches. By tailoring treatment to individual seizure patterns and pharmacological properties, chronopharmacology offers a personalized approach to improve outcomes in patients with epilepsy.

Repeated mild traumatic brain injury in mice elicits long term innate immune cell alterations in blood, spleen, and brain

Mild traumatic brain injury is an insidious event whereby the initial injury leads to ongoing secondary neuro- and systemic inflammation through various cellular pathways lasting days to months after injury. Here, we investigated the impact of repeated mild traumatic brain injury (rmTBI) and the resultant systemic immune response in male C57B6 mice using flow cytometric methodology on white blood cells (WBCs) derived from the blood and spleen. Isolated mRNA derived from spleens and brains of rmTBI mice was assayed for changes in gene expression at one day, one week, and one month following the injury paradigm. We observed increases in Ly6C+, Ly6C-, and total monocyte percentages in both blood and spleen at one month after rmTBI. Differential gene expression analysis for the brain and spleen tissues uncovered significant changes in many genes, including csf1r, itgam, cd99, jak1,cd3ε, tnfaip6, and nfil3. Additional analysis revealed alterations in several immune signaling pathways over the course of one month in the brain and spleen of rmTBI mice. Together, these results indicate that rmTBI produces pronounced gene expression changes in the brain and spleen. Furthermore, our data suggest that monocyte populations may reprogram towards the proinflammatory phenotype over extended periods of time after rmTBI.

Astrocytic control of extracellular GABA drives circadian timekeeping in the suprachiasmatic nucleus

The hypothalamic suprachiasmatic nucleus (SCN) is the master mammalian circadian clock. Its cell-autonomous timing mechanism, a transcriptional/translational feedback loop (TTFL), drives daily peaks of neuronal electrical activity, which in turn control circadian behavior. Intercellular signals, mediated by neuropeptides, synchronize and amplify TTFL and electrical rhythms across the circuit. SCN neurons are GABAergic, but the role of GABA in circuit-level timekeeping is unclear. How can a GABAergic circuit sustain circadian cycles of electrical activity, when such increased neuronal firing should become inhibitory to the network? To explore this paradox, we show that SCN slices expressing the GABA sensor iGABASnFR demonstrate a circadian oscillation of extracellular GABA ([GABA]e) that, counterintuitively, runs in antiphase to neuronal activity, with a prolonged peak in circadian night and a pronounced trough in circadian day. Resolving this unexpected relationship, we found that [GABA]e is regulated by GABA transporters (GATs), with uptake peaking during circadian day, hence the daytime trough and nighttime peak. This uptake is mediated by the astrocytically expressed transporter GAT3 (Slc6a11), expression of which is circadian-regulated, being elevated in daytime. Clearance of [GABA]e in circadian day facilitates neuronal firing and is necessary for circadian release of the neuropeptide vasoactive intestinal peptide, a critical regulator of TTFL and circuit-level rhythmicity. Finally, we show that genetic complementation of the astrocytic TTFL alone, in otherwise clockless SCN, is sufficient to drive [GABA]e rhythms and control network timekeeping. Thus, astrocytic clocks maintain the SCN circadian clockwork by temporally controlling GABAergic inhibition of SCN neurons.

PER2 integrates circadian disruption and pituitary tumorigenesis

Rationale: The role of circadian clock in pituitary tumorigenesis remains elusive. Here we investigate whether and how circadian clock modulates the development of pituitary adenomas. Methods and Results: We found altered expression of pituitary clock genes in patients with pituitary adenomas. In particular, PER2 is prominently upregulated. Further, jetlagged mice with PER2 upregulation have accelerated growth of GH3 xenograft tumor. Conversely, loss of Per2 protects mice against developing estrogen-induced pituitary adenoma. Similar antitumor effect is observed for SR8278, a chemical that can decrease pituitary PER2 expression. RNA-seq analysis suggests involvement of cell cycle disturbance in PER2 regulation of pituitary adenoma. Subsequent in vivo and cell-based experiments validate that PER2 induces pituitary expression of Ccnb2, Cdc20 and Espl1 (three cell cycle genes) to facilitate cell cycle progression and inhibit apoptosis, thereby promoting pituitary tumorigenesis. Mechanistically, PER2 regulates the transcription of Ccnb2, Cdc20 and Espl1 through enhancing the transcriptional activity of HIF-1α. HIF-1α trans-activates Ccnb2, Cdc20 and Espl1 via direct binding to its specific response element in the gene promoters. Conclusion: PER2 integrates circadian disruption and pituitary tumorigenesis. These findings advance our understanding of crosstalk between circadian clock and pituitary adenomas and highlight the relevance of clock-based approaches in disease management.

Rev-erbα agonist SR9009 protects against cerebral ischemic injury through mechanisms involving Nrf2 pathway

Backgrounds: The circadian clock protein Rev-erbα is a crucial regulator of circadian rhythms that affects multiple molecular, cellular, and physiology pathways that control susceptibility, injury, and recovery in the neurological disorders. Emerging evidence suggest that Rev-erbα plays a key role in the inflammation and oxidative stress, two pivotal mechanisms in the pathogenesis, progression, and recovery process of ischemic stroke. However, it remains inconclusive whether Rev-erbα activation is protective against ischemic brain damage. Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, a master regulator of inflammatory and oxidative responses. Our study aimed to determine whether pharmacological activation of Rev-erbα by SR9009 protects against acute ischemic brain damage partly via Nrf2 pathway.

Methods: Adult mice were pretreated with SR9009 or Nrf2 inhibitor all-trans-retinoic acid (ATRA) for 3 days prior to Sham or middle cerebral artery occlusion (MCAO) operation. After ischemia for 1 h and reperfusion for 24 h, the neurological function and cerebral infarction volume were determined, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and glutathione peroxidase (GSH-PX) activity in serum were detected by kit. The mRNA and/or protein level of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS), Period (Per)1, Brain and muscle arnt-like1 (Bmal1), Circadian locomotor output cycles kaput (Clock), Rev-erbα, Nrf2, heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO1) in cerebral cortex were detected by q-PCR and Western blot.

Results: We confirmed that SR9009 activated Rev-erbα gene in the cerebral cortex under basal condition. At 24 h after reperfusion, SR9009 ameliorated acute neurological deficits, reduced infarct volume. Meanwhile, the inflammatory TNF-α, IL-1β, iNOS and MDA content levels were significant decreased, SOD and GSH-PX activity were obviously increased, which were markedly blunted (or abolished) by ATRA. SR9009 enhanced the induction of Nrf2 and its downstream target genes HO-1 and NQO1 after ischemic insult. In addition, we found that SR9009 restored Rev-erbα, Bmal1, Clock, Per1 genes expression in the cerebral cortex under ischemic condition.

Conclusion: Taken together, Rev-erbα activation by SR9009 protects against ischemic stroke damage, at least, partly through Nrf2 pathway.

Reprogramming the Circadian Dynamics of Epileptic Genes in Mouse Temporal Lobe Epilepsy

Temporal lobe epilepsy (TLE) is a common and severe epilepsy displaying rhythmicity in humans and animals. However, how the circadian clock contributes to TLE remains elusive. A recent circadian analysis of the ventral hippocampal transcriptome of pilocarpine-induced TLE mice revealed as many as 1650 rhythmically expressed transcripts. Here, a comparison of the mouse ventral hippocampal transcriptome with the human epilepsy-related gene set identified 315 possible mouse epilepsy-related genes. Rhythmicity analysis classified them into arrhythmicity, loss-of-rhythmicity, gain-of-rhythmicity, and rhythmicity-maintaining groups. KEGG and GO analyses of these mouse epilepsy genes suggest their involvement in circadian entrainment. In TLE mice, Htr1d, Drd2, and Chrna3 lose rhythmicity, but P2rx7 gains rhythmicity; the up-regulation of Htr1d and Drd2 and down-regulation of Chrna3 inhibit adenylate cyclase (AC), and up-regulation of Htr1d, Drd2, and P2rx7 activates protein kinase C (PKC). Together, these results suggest that epilepsy can disrupt the circadian dynamics of the epileptic genes, shed light on possible TLE pathogenesis, and provide potential targets for TLE diagnosis and chronotherapy.

Circadian regulation of dentate gyrus excitability mediated by G-protein signaling

The central circadian regulator within the suprachiasmatic nucleus transmits time of day information by a diurnal spiking rhythm driven by molecular clock genes controlling membrane excitability. Most brain regions, including the hippocampus, harbor similar intrinsic circadian transcriptional machinery, but whether these molecular programs generate oscillations of membrane properties is unclear. Here, we show that intrinsic excitability of mouse dentate granule neurons exhibits a 24-h oscillation that controls spiking probability. Diurnal changes in excitability are mediated by antiphase G-protein regulation of potassium and sodium currents that reduce excitability during the Light phase. Disruption of the circadian transcriptional machinery by conditional deletion of Bmal1 enhances excitability selectively during the Light phase by removing G-protein regulation. These results reveal that circadian transcriptional machinery regulates intrinsic excitability by coordinated regulation of ion channels by G-protein signaling, highlighting a potential novel mechanism of cell-autonomous oscillations.

Clocking Epilepsies: A Chronomodulated Strategy-Based Therapy for Rhythmic Seizures

Epilepsy is a neurological disorder characterized by hypersynchronous recurrent neuronal activities and seizures, as well as loss of muscular control and sometimes awareness. Clinically, seizures have been reported to display daily variations. Conversely, circadian misalignment and circadian clock gene variants contribute to epileptic pathogenesis. Elucidation of the genetic bases of epilepsy is of great importance because the genetic variability of the patients affects the efficacies of antiepileptic drugs (AEDs). For this narrative review, we compiled 661 epilepsy-related genes from the PHGKB and OMIM databases and classified them into 3 groups: driver genes, passenger genes, and undetermined genes. We discuss the potential roles of some epilepsy driver genes based on GO and KEGG analyses, the circadian rhythmicity of human and animal epilepsies, and the mutual effects between epilepsy and sleep. We review the advantages and challenges of rodents and zebrafish as animal models for epileptic studies. Finally, we posit chronomodulated strategy-based chronotherapy for rhythmic epilepsies, integrating several lines of investigation for unraveling circadian mechanisms underpinning epileptogenesis, chronopharmacokinetic and chronopharmacodynamic examinations of AEDs, as well as mathematical/computational modeling to help develop time-of-day-specific AED dosing schedules for rhythmic epilepsy patients.

Brain nuclear receptors and cardiovascular function

Brain-heart interaction has raised up increasing attentions. Nuclear receptors (NRs) are abundantly expressed in the brain, and emerging evidence indicates that a number of these brain NRs regulate multiple aspects of cardiovascular diseases (CVDs), including hypertension, heart failure, atherosclerosis, etc. In this review, we will elaborate recent findings that have established the physiological relevance of brain NRs in the context of cardiovascular function. In addition, we will discuss the currently available evidence regarding the distinct neuronal populations that respond to brain NRs in the cardiovascular control. These findings suggest connections between cardiac control and brain dynamics through NR signaling, which may lead to novel tools for the treatment of pathological changes in the CVDs.

Puerariae lobatae radix protects against UVB-induced skin aging via antagonism of REV-ERBα in mice

Puerariae lobatae radix (PLR) is a wildly used herbal medicine. Here we aimed to assess the PLR efficacy against UVB (ultraviolet-B)-induced skin aging and to determine the mechanisms thereof. We found a significant protective effect of PLR (topical application) on UVB-induced skin aging in mice, as evidenced by reduced skin wrinkles, epidermal thickness, and MDA (malondialdehyde) content as well as increased levels of HYP (hydroxyproline) and SOD (superoxide dismutase) in the skin. In the meantime, Mmp-1, p21 and p53 levels were decreased in the skin of PLR-treated mice. Anti-aging effects of PLR were also confirmed in L929 cells. Furthermore, PLR up-regulated skin expression of BMAL1, which is a known regulator of aging by promoting Nrf2 and antioxidant enzymes. Consistently, Nrf2 and several genes (i.e., Prdx6, Sod1, and Sod2) encoding antioxidant enzymes in the skin were increased in PLR-treated mice. Moreover, based on Gal4 chimeric assay, Bmal1 reporter gene and expression assays, we identified PLR as an antagonist of REV-ERBα that can increase Bmal1 expression. Intriguingly, loss of Rev-erbα protected mice against UVB-induced skin aging and abrogated the protective effect of PLR. In conclusion, PLR acts as an antagonist of REV-ERBα and promotes the expression of BMAL1 to protect against skin aging in mice.

Tangeretin prevents cognitive deficit in delirium through activating RORα/γ-E4BP4 axis in mice

Delirium is a common and serious neuropsychiatric syndrome characterized with acute cognitive and attentional deficits, however, the effective therapies are lacking. Here, using mouse models of delirium, we investigated the effects of tangeretin (TAN, a natural flavonoid) on cognitive impairment by assessing object preference with novel object recognition (NOR) test and spontaneous alternation with Y maze test. We found that TAN, as a RORα/γ agonist, prevented cognitive decline in delirious mice as evidenced by a normal novel object preference and increased spontaneous alternation. This was accompanied by decreased expression of ERK1/2, TNFα and IL-1β as well as diminished microglial activation in delirious mice. The protective effect of TAN on delirium was mainly attributed to increased hippocampal E4BP4 expression (a known target of RORs and a regulator of cognition in delirium through modulating the ERK1/2 cascade and microglial activation) via activation of RORα/γ. In addition, TAN treatment modulated the expression of RORα/γ target genes (such as E4bp4 and Bmal1) and inhibited the expression of TNFα and IL-1β in lipopolysaccharide (LPS)-stimulated cells, supporting a beneficial effect of TAN on delirium. In conclusion, TAN is identified as a RORα/γ agonist which promotes E4BP4 expression to prevent cognitive decline in delirious mice. Our findings may have implications for drug development of TAN for prevention and treatment of various diseases associated with cognitive deficiency.

Chronobiology of epilepsy and sudden unexpected death in epilepsy

Epilepsy is a neurological disease characterized by spontaneous, unprovoked seizures. Various insults render the brain hyperexcitable and susceptible to seizure. Despite there being dozens of preventative anti-seizure medications available, these drugs fail to control seizures in nearly 1 in 3 patients with epilepsy. Over the last century, a large body of evidence has demonstrated that internal and external rhythms can modify seizure phenotypes. Physiologically relevant rhythms with shorter periodic rhythms, such as endogenous circadian rhythms and sleep-state, as well as rhythms with longer periodicity, including multidien rhythms and menses, influence the timing of seizures through poorly understood mechanisms. The purpose of this review is to discuss the findings from both human and animal studies that consider the effect of such biologically relevant rhythms on epilepsy and seizure-associated death. Patients with medically refractory epilepsy are at increased risk of sudden unexpected death in epilepsy (SUDEP). The role that some of these rhythms play in the nocturnal susceptibility to SUDEP will also be discussed. While the involvement of some of these rhythms in epilepsy has been known for over a century, applying the rhythmic nature of such phenomenon to epilepsy management, particularly in mitigating the risk of SUDEP, has been underutilized. As our understanding of the physiological influence on such rhythmic phenomenon improves, and as technology for chronic intracranial epileptiform monitoring becomes more widespread, smaller and less invasive, novel seizure-prediction technologies and time-dependent chronotherapeutic seizure management strategies can be realized.

E4BP4 Coordinates Circadian Control of Cognition in Delirium

Improved understanding of the etiologies of delirium, a common and severe neuropsychiatric syndrome, would facilitate the disease prevention and treatment. Here, the authors invesitgate the role of circadian rhythms in the pathogenesis of delirium. They observe perturbance of circadian rhythms in mouse models of delirium and disrupted clock gene expression in patients with delirium. In turn, physiological and genetic circadian disruptions sensitize mice to delirium with aggravated cognitive impairment. Likewise, global deletion of E4bp4 (E4 promoter-binding protein), a clock gene markedly altered in delirium conditions, results in exacerbated delirium-associated cognitive decline. Cognitive decline in delirium models is attributed to microglial activation and impaired long-term potentiation in the hippocampus. Single-cell RNA-sequencing reveals microglia as the regulatory target of E4bp4. E4bp4 restrains microglial activation via inhibiting the ERK1/2 signaling pathway. Supporting this, mice lacking in microglial E4bp4 are delirious prone, whereas mice with E4bp4 specifically deleted in hippocampal CA1 neurons have a normal phenotype. Mechanistically, E4bp4 inhibits ERK1/2 signaling by trans-repressing Mapk1/3 (genes encoding ERK1/2) via direct binding to a D-box element in the promoter region. These findings define a causal role of clock dysfunction in delirium development and indicate E4bp4 as a regulator of cognition at the crosstalk between circadian clock and delirium.

The Clock gene regulates kainic acid-induced seizures through inhibiting ferroptosis in mice

OBJECTIVES

Temporal lobe epilepsy (TLE) is a common and intractable form of epilepsy. There is a strong need to better understand molecular events underlying TLE and to find novel therapeutic agents. Here we aimed to investigate the role of Clock and ferroptosis in regulating TLE.

METHODS

TLE model was established by treating mice with kainic acid (KA). Regulatory effects of the Clock gene on KA-induced seizures and ferroptosis were evaluated using Clock knockout (Clock-/-) mice. mRNA and protein levels were determined by quantitative real-time PCR and western blotting, respectively. Ferroptosis was assessed by measuring the levels of iron, GSH and ROS. Transcriptional regulation was studied using a combination of luciferase reporter, mobility shift and chromatin immunoprecipitation (ChIP) assays.

KEY FINDINGS

We found that Clock ablation exacerbated KA-induced seizures in mice, accompanied by enhanced ferroptosis in the hippocampus. Clock ablation reduced the hippocampal expression of GPX4 and PPAR-γ, two ferroptosis-inhibitory factors, in mice and in N2a cells. Moreover, Clock regulates diurnal expression of GPX4 and PPAR-γ in mouse hippocampus and rhythmicity in KA-induced seizures. Consistent with this finding, Clock overexpression up-regulated GPX4 and PPAR-γ and protected against ferroptosis in N2a cells. In addition, luciferase reporter, mobility shift and ChIP assays showed that CLOCK trans-activated Gpx4 and Ppar-γ through direct binding to the E-box elements in the gene promoters.

CONCLUSION

CLOCK protects against KA-induced seizures through increased expression of GPX4 and PPAR-γ and inhibition of ferroptosis.

Rev-erbα Knockout Reduces Ethanol Consumption and Preference in Male and Female Mice

Alcohol use is a contributor in the premature deaths of approximately 3 million people annually. Among the risk factors for alcohol misuse is circadian rhythm disruption; however, this connection remains poorly understood. Inhibition of the circadian nuclear receptor REV-ERBα is known to disrupt molecular feedback loops integral to daily oscillations, and impact diurnal fluctuations in the expression of proteins required for reward-related neurotransmission. However, the role of REV-ERBα in alcohol and substance use-related phenotypes is unknown. Herein, we used a Rev-erbα knockout mouse line and ethanol two-bottle choice preference testing to show that disruption of Rev-erbα reduces ethanol preference in male and female mice. Rev-erbα null mice showed the lowest ethanol preference in a two-bottle choice test across all genotypes, whereas there were no ethanol preference differences between heterozygotes and wildtypes. In a separate experiment, alcohol-consuming wildtype C57Bl/6N mice were administered the REV-ERBα/β inhibitor SR8278 (25 mg/kg or 50 mg/kg) for 7 days and alcohol preference was evaluated daily. No differences in alcohol preference were observed between the treatment and vehicle groups. Our data provides evidence that genetic variation in REV-ERBα may contribute to differences in alcohol drinking.

OUP accepted manuscript

Aims

Adverse cardiovascular events have day/night patterns with peaks in the morning, potentially related to endogenous circadian clock control of platelet activation. Circadian nuclear receptor Rev-erbα is an essential and negative component of the circadian clock. To date, the expression profile and biological function of Rev-erbα in platelets have never been reported.

Methods and results

Here, we report the presence and functions of circadian nuclear receptor Rev-erbα in human and mouse platelets. Both human and mouse platelet Rev-erbα showed a circadian rhythm that positively correlated with platelet aggregation. Global Rev-erbα knockout and platelet-specific Rev-erbα knockout mice exhibited defective in haemostasis as assessed by prolonged tail-bleeding times. Rev-erbα deletion also reduced ferric chloride-induced carotid arterial occlusive thrombosis, prevented collagen/epinephrine-induced pulmonary thromboembolism, and protected against microvascular microthrombi obstruction and infarct expansion in an acute myocardial infarction model. In vitro thrombus formation assessed by CD41-labelled platelet fluorescence intensity was significantly reduced in Rev-erbα knockout mouse blood. Platelets from Rev-erbα knockout mice exhibited impaired agonist-induced aggregation responses, integrin αIIbβ3 activation, and α-granule release. Consistently, pharmacological inhibition of Rev-erbα by specific antagonists decreased platelet activation markers in both mouse and human platelets. Mechanistically, mass spectrometry and co-immunoprecipitation analyses revealed that Rev-erbα potentiated platelet activation via oligophrenin-1-mediated RhoA/ERM (ezrin/radixin/moesin) pathway.

Conclusion

We provided the first evidence that circadian protein Rev-erbα is functionally expressed in platelets and potentiates platelet activation and thrombus formation. Rev-erbα may serve as a novel therapeutic target for managing thrombosis-based cardiovascular disease.

Key question

Adverse cardiovascular events have day/night patterns with peaks in the morning, potentially related to endogenous circadian clock control of platelet activation. Whether circadian nuclear receptor Rev-erba is present in platelets and regulates platelet function remains unknown.

Key finding

We provide the first evidence that Rev-erba is functionally expressed in platelets and acts as a positive regulator of platelet activation/thrombus formation through the oligophrenin-1-mediated RhoA/ERM signalling pathway.

Take home message

Our observations highlight the importance of circadian clock machinery in platelet physiology and support the notion that Rev-erba may serve as a novel therapeutic target for managing thrombosis-based cardiovascular diseases.

Loss of MeCP2 increases GABA uptake by astrocytes to suppress tonic inhibition of CA1 pyramidal neurons

Rett syndrome (RTT) is a neurodevelopmental disorder characterized a spectrum of phenotypes affecting neuronal and glial populations. Recent work by Dong et al. (Dong Q, Kim J, Nguyen L, Bu Q, Chang Q. J Neurosci 40: 6250-6261, 2020) suggests that augmented GABA uptake by astrocytes diminishes tonic inhibition in the hippocampus and contributes to increased seizure propensity in RTT. Here, I will review evidence supporting this possibility and critically evaluate how increased expression of a GABA transporter might contribute to this mechanism.

Decreased expression of the clock gene Bmal1 is involved in the pathogenesis of temporal lobe epilepsy

Clock genes not only regulate the circadian rhythm of physiological activities but also participate in the pathogenesis of many diseases. Previous studies have documented the abnormal expression of clock genes in epilepsy. However, the molecular mechanism of brain and muscle Arnt-like protein 1 (Bmal1), one of the core clock genes, in the epileptogenesis and seizures of temporal lobe epilepsy (TLE) remain unclear. We first investigated the levels of Bmal1 and other clock proteins in the hippocampus of subjects with epilepsy to define the function of Bmal1. The levels of Bmal1 were decreased during the latent and chronic phases in the experimental group compared with those in the control group. Knockout of Bmal1 in hippocampal dentate gyrus (DG) neurons of Bmal1flox/flox mice by Synapsin 1 (Syn1) promoter AAV (adeno-associated virus) lowered the threshold of seizures induced by pilocarpine administration. High-throughput sequencing analysis showed that PCDH19 (protocadherin 19), a gene associated with epilepsy, was regulated by Bmal1. PCDH19 expression was also decreased in the hippocampus of epileptic mice. Furthermore, the higher levels of Bmal1 and PCDH19 were detected in patients with no hippocampal sclerosis (no HS) than in patients with HS International League Against Epilepsy (ILAE) type I and III. Altogether, these data suggest that decreased expression of clock gene Bmal1 may participate in epileptogenesis and seizures via PCDH19 in TLE.

Stopping the Clock on Seizures!

A recent paper by Zhang et al. shows that REV-ERBα, a negative regulator of the circadian molecular clock, is pro-convulsant through its action on GABA signaling. The findings support the role of the circadian molecular clock in epilepsy and suggest REV-ERBα as a potential therapeutic target for the management of seizures.