The immunosuppressant cyclosporin A inhibits recurrent seizures in an experimental model of temporal lobe epilepsy

Three-dimensional highly porous hydrogel scaffold for neural circuit dissection and modulation

Biomimetic brain structures and artificial neural networks have provided a simplified strategy for quantitatively investigating the complex structural and functional characteristics of highly interconnected neural networks. To achieve this, three-dimensional (3D) cell culture approaches have attracted much attention, which can mimic cell-cell interactions at the organism level and help better understand the function of specific neurons and neuronal networks than traditional two-dimensional cell culture methods. However, 3D scaffolds similar to the natural extracellular matrix to support the culturing, recording, and manipulation of neurons have long been an unresolved challenge. To resolve this, 3D hydrogel scaffolds can be fabricated via an innovative thermal treatment followed by an esterification process. A highly porous microstructure was formed within the bulk hydrogel scaffold, which showed a high porosity of 91% and a low Young's modulus of 6.11 kPa. Due to the merits of the fabricated hydrogel scaffolds, we constructed 3D neural networks and detected spontaneous action potentials in vitro. We successfully induced seizure-like waveforms in 3D cultured neurons and suppressed hyperactivated discharges by selectively activating γ-aminobutyric acid-ergic (GABAergic) interneurons. These results prove the advantages of our hydrogel scaffolds and demonstrate their application potential in the accurate dissection of neural circuits, which may help develop effective treatments for various neurological disorders. STATEMENT OF SIGNIFICANCE: While 3D cell culture approaches have attracted much attention and offer more advantages than two-dimensional cell culture methods, 3D scaffolds similar to the natural extracellular matrix to support the culturing, recording, and manipulation of neurons have long been an unresolved challenge. Herein, we developed a simplified and low-cost strategy for fabricating highly porous and cytocompatible hydrogel scaffolds for the construction of three-dimensional (3D) neural networks in vitro. The cultured 3D neural networks can mimic the in vivo connection among different neuron subgroups and help accurately dissect and manipulate the structure and function of specific neural circuits.

Epileptic Seizures After Allogeneic Hematopoietic Stem Cell Transplantation

Technique in allogeneic hematopoietic stem cell transplantation has greatly advanced over the past decades, which has led to an increase in the number of patients receiving transplantation, but the complex procedure places these transplant recipients at high risk of a large spectrum of complications including neurologic involvement. As a common manifestation of neurological disorders, epileptic seizures after transplantation have been of great concern to clinicians because it seriously affects the survival rate and living quality of those recipients. The aim of this review is to elucidate the incidence of seizures after allogeneic hematopoietic stem cell transplantation, and to further summarize in detail its etiologies, possible mechanisms, clinical manifestations, therapeutic schedule, and prognosis, hoping to improve doctors' understandings of concurrent seizures following transplantation, so they can prevent, process, and eventually improve the survival and outlook for patients in a timely manner and correctly.

Differentially expressed circRNA and functional pathways in the hippocampus of epileptic mice based on next-generation sequencing

Epilepsy is a clinical syndrome caused by the highly synchronized abnormal discharge of brain neurons. It has the characteristics of paroxysmal, transient, repetitive, and stereotyped. Circular RNAs (circRNAs) are a recently discovered type of noncoding RNA with diverse cellular functions related to their excellent stability; additionally, some circRNAs can bind and regulate microRNAs (miRNAs). The present study was designed to screen the differentially expressed circRNA in an acute seizure model of epilepsy in mice, analyze the related miRNA and mRNA, and study their participating functions and enrichment pathways. In order to obtain the differential expression of circRNA in epilepsy and infer their function, we used next-generation sequencing and found significantly different transcripts. CIRI (circRNA identifier) software was used to predict circRNA from the hippocampus cDNA, EdgeR was applied for the differential circRNA analysis between samples, and Cytoscape 3.7.2 software was used to draw the network diagram. A total of 10,388 differentially expressed circRNAs were identified, of which 34 were upregulated and 66 were downregulated. Among them, mm9_circ_008777 and mm9_circ_004424 were the key upregulated genes, and their expression in the epilepsy group was verified using Quantitative real-time PCR (QPCR). The analysis indicated that the extracted gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways were closely related to several epilepsy-associated processes. This study determined that mm9_circ_008777 and mm9_circ_004424 are potential biomarkers of epilepsy, which play important roles in epilepsy-related pathways. These results could help improve the understanding of the biological mechanisms of circRNAs and epilepsy treatments.

Cyclosporin A ameliorates eclampsia seizure through reducing systemic inflammation in an eclampsia-like rat model

Our previous studies have shown that the maternal hyperinflammatory response in pre-eclampsia lowered the eclampsia-like seizure threshold. Cyclosporin A (CsA), which is an effective immunosuppressant, could attenuate the inflammatory responses in LPS-induced pre-eclampsia rats. Here, we hypothesized that CsA may ameliorate seizure severity through reducing systemic inflammation in pre-eclampsia/eclampsia. In the current study, the effects of CsA on pre-eclampsia manifestation, eclampsia-like seizure activities and systemic inflammation were examined in a pre-eclampsia model. Pregnant rats were given an intraperitoneal injection of the epileptogenic drug pentylenetetrazol (PTZ) following a tail vein injection of lipopolysaccharide to establish the eclampsia-like seizure model. CsA (5 mg/kg) was administered intravenously through the tail after LPS infusion. Mean systolic blood pressure and proteinuria in pre-eclampsia were detected. After PTZ injection, seizure activity was assessed, inflammatory responses were determined and pregnancy outcomes were analyzed. The results showed that CsA treatment significantly decreased blood pressure and proteinuria and increased the fetal and placental weight (P < 0.01). Meanwhile, CsA treatment significantly reduced serum IL-1β, TNF-α, and IL-17 levels (P < 0.01), decreased the seizure scores and prolonged the latency to seizure (P < 0.01). CsA effectively attenuated pre-eclampsia manifestation and eclampsia-like seizure severity. In addition, CsA treatment significantly reduced the inflammatory cytokine levels and improved pregnancy outcomes following eclampsia-like seizures. The decreased inflammatory cytokines in pre-eclampsia are coincident with attenuated pre-eclampsia manifestation after CsA treatment, suggesting that CsA treatment might decrease the eclampsia-like seizure severity through decreasing systemic inflammation in pre-eclasmpsia/eclampsia.

Possible epigenetic regulatory effect of dysregulated circular RNAs in epilepsy

Circular RNAs (circRNAs) involve in the epigenetic regulation and its major mechanism is the sequestration of the target micro RNAs (miRNAs). We hypothesized that circRNAs might be related with the pathophysiology of chronic epilepsy and evaluated the altered circRNA expressions and their possible regulatory effects on their target miRNAs and mRNAs in a mouse epilepsy model. The circRNA expression profile in the hippocampus of the pilocarpine mice was analyzed and compared with control. The correlation between the expression of miRNA binding sites (miRNA response elements, MRE) in the dysregulated circRNAs and the expression of their target miRNAs was evaluated. As miRNAs also inhibit their target mRNAs, circRNA–miRNA-mRNA regulatory network, comprised of dysregulated RNAs that targets one another were searched. For the identified networks, bioinformatics analyses were performed. As the result, Forty-three circRNAs were dysregulated in the hippocampus (up-regulated, 26; down-regulated, 17). The change in the expression of MRE in those circRNAs negatively correlated with the change in the relevant target miRNA expression (r = -0.461, P<0.001), supporting that circRNAs inhibit their target miRNA. 333 dysregulated circRNA–miRNA-mRNA networks were identified. Gene ontology and pathway analyses demonstrated that the up-regulated mRNAs in those networks were closely related to the major processes in epilepsy. Among them, STRING analysis identified 37 key mRNAs with abundant (≥4) interactions with other dysregulated target mRNAs. The dysregulation of the circRNAs which had multiple interactions with key mRNAs were validated by PCR. We concluded that dysregulated circRNAs might have a pathophysiologic role in chronic epilepsy by regulating multiple disease relevant mRNAs via circRNA−miRNA−mRNA interactions.

Probing Mitochondrial Permeability Transition Pore Activity in Nucleated Cells and Platelets by High-Throughput Screening Assays Suggests Involvement of Protein Phosphatase 2B in Mitochondrial Dynamics

Mitochondrial permeability transition pore (mPTP) formation is well documented in isolated mitochondria. However, convincing detection of mPTP in whole cells remains elusive. In this study, we describe a high-throughput assay for Ca²⁺-activated mPTP opening in platelets using HyperCyt flow cytometry. In addition, we demonstrate that in several nucleated cells, using multiple approaches, the detection of cyclophilin D-dependent mPTP opening is highly challenging. Results with the mitochondrial-targeted Ca²⁺-sensing green fluorescent protein (mito-Case12) suggest the involvement of protein phosphatase 2B (PP2B; calcineurin) in regulating mitochondrial dynamics. Our results highlight the danger of relying on cyclosporine A alone as a pharmacological tool, and the need for comprehensive studies of mPTP in the cell.

Seizures after transplantation

PURPOSE

To summarize information on the history, incidence, clinical manifestation, best treatment, as well as prognosis of seizures in transplant recipients.

METHODS

In October 2017, we searched the literature on PubMed in English with the search terms: "transplantation" AND "seizure", "transplantation" AND "epilepsy", "transplantation"AND "status epilepticus", "immunosuppressant" AND "seizure", "immunosuppressant" AND "epilepsy". Publications not based on new data and original research were not included in this article.

RESULTS

Seizures including generalized seizures, focal seizures and status epilepticus are a common central nervous system complication after transplantation. The incidence of seizures varied between different kinds of transplantations. The reported incidence of seizures was 7%-27% in association with solid organ transplantations and 1.6%-15.4% with hematopoietic stem cell transplantation. Most of seizures appeared in the early post-transplantation period. Patients often had a favorable prognosis, however, in some conditions, recurrent or intractable seizures may occur.

CONCLUSIONS

The underlying pathogenesis of new-onset seizures or epilepsy in recipients of transplantation needs to be further elucidated. In addition, more information is required from prospective studies and research focusing on therapeutic strategies.

Effects Following Intracerebroventricular Injection of Immunosuppressant Cyclosporine A On Inhibitory Avoidance Learning and Memory in Mice

Background:

Protein phosphatase-2B or calcineurin (CN) is the main phosphatase and a critical regulator of cellular pathways for learning, memory, and plasticity. Cyclosporine A(CyA), a phosphatase and peptidyl-prolyl cis/trans isomerase inhibitor, is a common immune suppressant extensively used in tissue transplantation. To further clarify the role of CN in different stages of learning and memory, the aim of the present study was to evaluate the role of CyA in an inhibitory avoidance (IA) model in mice.

Materials and Methods:

Using intracerebroventricular (ICV) injection of different doses of CyA (0.5, 5, and 50 nM) at different periods (pre-/post-training and pre-test), the effect of the drug was evaluated in a step-down IA paradigm. The latency of step-down (sec) was considered a criterion for memory performance.

Results:

The pre-training injections of CyA (0.5, 5 nM), however not of 50 nM, impaired IA learning acquisition. The post-training injection of high-dose CyA (50 nM) impaired memory consolidation. The pre-test ICV CyA injection did not impair memory retrieval; the ICV injection of CyA caused no change in locomotion.

Conclusion:

These findings suggest that CyA selectively interferes with acquisition, retention, but not retrieval, of information processing in mice. Given the crucial role of CN in common signaling pathway of memory performance and cognition, it could be a probable therapeutic target in the treatment of a wide variety of neurological conditions involving memory.

A Friend or Foe: Calcineurin across the Gamut of Neurological Disorders

The serine/threonine phosphatase calcineurin (CaN) is a unique but confounding calcium/calmodulin-mediated enzyme. CaN has shown to play essential roles from regulating calcium homeostasis to being an intricate part of learning and memory formation. Neurological disorders, despite differing in their etiology, share similar pathological outcomes, such as mitochondrial dysfunction and apoptotic signaling brought about by excitotoxic elements. CaN, being deeply integrated in vital neuronal functions, may be implicated in various neurological disorders. Understanding the enzyme and its physiological niche in the nervous system is vital in uncovering its roles in the spectrum of brain disorders. By reviewing the crosstalk in different neurological pathologies, a possible grasp of CaN's complex signaling may lead to forming better neurotherapy. This Outlook attempts to explore the various neuronal functions of CaN and investigate its pervasive role through the gamut of neurological disorders.

Mitochondrial Ca2+ and regulation of the permeability transition pore

The mitochondrial permeability transition pore was originally described in the 1970's as a Ca2+ activated pore and has since been attributed to the pathogenesis of many diseases. Here we evaluate how each of the current models of the pore complex fit to what is known about how Ca2+ regulates the pore, and any insight that provides into the molecular identity of the pore complex. We also discuss the central role of Ca2+ in modulating the pore's open probability by directly regulating processes, such as ATP/ADP balance through the tricarboxylic acid cycle, electron transport chain, and mitochondrial membrane potential. We review how Ca2+ influences second messengers such as reactive oxygen/nitrogen species production and polyphosphate formation. We discuss the evidence for how Ca2+ regulates post-translational modification of cyclophilin D including phosphorylation by glycogen synthase kinase 3 beta, deacetylation by sirtuins, and oxidation/ nitrosylation of key residues. Lastly we introduce a novel view into how Ca2+ activated proteolysis through calpains in the mitochondria may be a driver of sustained pore opening during pathologies such as ischemia reperfusion injury.

Ultrasound stimulation inhibits recurrent seizures and improves behavioral outcome in an experimental model of mesial temporal lobe epilepsy

Current therapies for epilepsy consist mostly of pharmacological agents or invasive surgery. Recently, ultrasound (US) stimulation has been considered a promising tool for the noninvasive treatment of brain diseases, including epilepsy. However, in temporal lobe epilepsy (TLE), a common form of epilepsy, neurophysiological and functional outcomes following US stimulation are not well defined. To address this, we developed a paradigm of transcranial pulsed US stimulation to efficiently suppress seizure activity in the initial/acute period in a kainate (KA)-induced mouse model of mesial TLE. Pulsed US stimulation inhibited acute seizure activity and either delayed the onset of or suppressed status epilepticus (SE). Kainate-treated mice that had received US stimulation in the initial period exhibited fewer spontaneous recurrent seizures (SRSs) and improved performance in behavioral tasks assessing sociability and depression in the chronic period of epilepsy. Our results demonstrate that US stimulation in the acute period of epilepsy can inhibit SRSs and improve behavioral outcomes in a mouse model of mesial TLE. The present study suggests that noninvasive transcranial pulsed US stimulation may be feasible as an adjuvant therapy in patients with epilepsy. This article is part of a Special Issue entitled "Status Epilepticus".

Ketone bodies mediate antiseizure effects through mitochondrial permeability transition

OBJECTIVE

Ketone bodies (KB) are products of fatty acid oxidation and serve as essential fuels during fasting or treatment with the high-fat antiseizure ketogenic diet (KD). Despite growing evidence that KB exert broad neuroprotective effects, their role in seizure control has not been firmly demonstrated. The major goal of this study was to demonstrate the direct antiseizure effects of KB and to identify an underlying target mechanism.

METHODS

We studied the effects of both the KD and KB in spontaneously epileptic Kcna1-null mice using a combination of behavioral, planar multielectrode, and standard cellular electrophysiological techniques. Thresholds for mitochondrial permeability transition (mPT) were determined in acutely isolated brain mitochondria.

RESULTS

KB alone were sufficient to: (1) exert antiseizure effects in Kcna1-null mice, (2) restore intrinsic impairment of hippocampal long-term potentiation and spatial learning-memory defects in Kcna1-null mutants, and (3) raise the threshold for calcium-induced mPT in acutely prepared mitochondria from hippocampi of Kcna1-null animals. Targeted deletion of the cyclophilin D subunit of the mPT complex abrogated the effects of KB on mPT, and in vivo pharmacological inhibition and activation of mPT were found to mirror and reverse, respectively, the antiseizure effects of the KD in Kcna1-null mice.

INTERPRETATION

The present data reveal the first direct link between mPT and seizure control, and provide a potential mechanistic explanation for the KD. Given that mPT is increasingly being implicated in diverse neurological disorders, our results suggest that metabolism-based treatments and/or metabolic substrates might represent a worthy paradigm for therapeutic development.

Neurobehavioral consequences of small molecule-drug immunosuppression

60 years after the first successful kidney transplantation in humans, transplant patients have decent survival rates owing to a broad spectrum of immunosuppressive medication available today. Not only transplant patients, but also patients with inflammatory autoimmune diseases or cancer benefit from these life-saving immunosuppressive and anti-proliferative medications. However, this success is gained with the disadvantage of neuropsychological disturbances and mental health problems such as depression, anxiety and impaired quality of life after long-term treatment with immunosuppressive drugs. So far, surprisingly little is known about unwanted neuropsychological side effects of immunosuppressants and anti-proliferative drugs from the group of so called small molecule-drugs. This is partly due to the fact that it is difficult to disentangle whether and to what extent the observed neuropsychiatric disturbances are a direct result of the patient's medical history or of the immunosuppressive treatment. Thus, here we summarize experimental as well as clinical data of mammalian and human studies, with the focus on selected small-molecule drugs that are frequently employed in solid organ transplantation, autoimmune disorders or cancer therapy and their effects on neuropsychological functions, mood, and behavior. These data reveal the necessity to develop immunosuppressive and anti-proliferative drugs inducing fewer or no unwanted neuropsychological side effects, thereby increasing the quality of life in patients requiring long term immunosuppressive treatment. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'.

Inter-individual variation in the effect of antiepileptic drugs in the intrahippocampal kainate model of mesial temporal lobe epilepsy in mice

Despite more than 20 clinically approved antiepileptic drugs (AEDs), there remains a substantial unmet clinical need for patients with refractory (AED-resistant) epilepsy. Animal models of refractory epilepsy are needed for at least two goals; (1) better understanding of the mechanisms underlying resistance to AEDs, and (2) development of more efficacious AEDs for patients with refractory seizures. It is only incompletely understood why two patients with seemingly identical types of epilepsy and seizures may respond differently to the same AED. Prompted by this well-known clinical phenomenon, we previously evaluated whether epileptic rats respond differently to AEDs and discovered AED responsive and resistant animals in the same models. In the present study, we used the same approach for the widely used intrahippocampal kainate mouse model of mesial temporal lobe epilepsy. In a first step, we examined anti-seizure effects of 6 AEDs on spontaneous recurrent focal electrographic seizures and secondarily generalized convulsive seizures in epileptic mice, showing that the focal nonconvulsive seizures were resistant to carbamazepine and phenytoin, whereas valproate and levetiracetam exerted moderate and phenobarbital and diazepam marked anti-seizure effects. All AEDs seemed to suppress generalized convulsive seizures. Next we investigated the inter-individual variation in the anti-seizure effects of these AEDs and, in case of focal seizures, found responders and nonresponders to all AEDs except carbamazepine. Most nonresponders were resistant to more than one AED. Our data further validate the intrahippocampal kainate mouse model as a model of difficult-to-treat focal seizures that can be used to investigate the determinants of AED efficacy.

Differential regulation of observational fear and neural oscillations by serotonin and dopamine in the mouse anterior cingulate cortex

RATIONALE

The aberrant regulation of serotonin (5-HT) and dopamine (DA) in the brain has been implicated in neuropsychiatric disorders associated with marked impairments in empathy, such as schizophrenia and autism. Many psychiatric drugs bind to both types of receptors, and the anterior cingulate cortex (ACC) is known to be centrally involved with empathy. However, the relationship between the 5-HT/DA system in the ACC and empathic behavior is not yet well known.

OBJECTIVES

We investigated the role of 5-HT/DA in empathy-like behavior and in the regulation of ACC neural activity.

METHODS

An observational fear learning task was conducted following microinjections of 5-HT, DA, 5-HT and DA, methysergide (5-HT receptor antagonist), SCH-23390 (DA D1 receptor antagonist), or haloperidol (DA D2 receptor antagonist) into the mouse ACC. The ACC neural activity influenced by 5-HT and DA was electrophysiologically characterized in vitro and in vivo.

RESULTS

The microinjection of haloperidol, but not methysergide or SCH-23390, decreased the fear response of observing mice. The administration of 5-HT and 5-HT and DA together, but not DA alone, reduced the freezing response of observing mice. 5-HT enhanced delta-band activity and reduced alpha- and gamma-band activities in the ACC, whereas DA reduced only alpha-band activity. Based on entropy, reduced complexity of ACC neural activity was observed with 5-HT treatment.

CONCLUSIONS

The current results demonstrated that DA D2 receptors in the ACC are required for observational fear learning, whereas increased 5-HT levels disrupt observational fear and alter the regularity of ACC neural oscillations.

Anti-epileptic effects of neuropeptide Y gene transfection into the rat brain

Neuropeptide Y gene transfection into normal rat brain tissue can provide gene overexpression, which can attenuate the severity of kainic acid-induced seizures. In this study, a recombinant adeno-associated virus carrying the neuropeptide Y gene was transfected into brain tissue of rats with kainic acid-induced epilepsy through stereotactic methods. Following these transfections, we verified overexpression of the neuropeptide Y gene in the epileptic brain. Electroencephalograms showed that seizure severity was significantly inhibited and seizure latency was significantly prolonged up to 4 weeks after gene transfection. Moreover, quantitative fluorescent PCR and western blot assays revealed that the mRNA and protein expression of the N-methyl-D-aspartate receptor subunits NR1, NR2A, and NR2B was inhibited in the hippocampus of epileptic rats. These findings indicate that neuropeptide Y may inhibit seizures via down-regulation of the functional expression of N-methyl-D-aspartate receptors.

Immunomodulatory treatments in epilepsy

The role of immunity and inflammation appears to be an integral part of the pathogenic processes associated with some seizures, particularly with refractory epilepsy. Prompt treatment with immunotherapy may lead to better outcomes. Immune treatment options for treatment of epilepsy include therapies such as corticosteroids, immunoglobulins, plasmapheresis, or steroid-sparing drugs such as azathioprine. Recent alternatives have included even more aggressive treatment with cyclophosphamide, anti-pre-B-lymphocyte monoclonal antibody rituximab, and monoclonal antibodies such as efalizumab or natalizumab, which are presently used for other inflammatory disorders. Randomized controlled trials of immunotherapy in presumed autoimmune epilepsy are needed to provide further support for the rapid use of immunotherapy in patients with immune mediated epilepsy.

Population-level evidence for an autoimmune etiology of epilepsy

IMPORTANCE

Epilepsy is a debilitating condition, often with neither a known etiology nor an effective treatment. Autoimmune mechanisms have been increasingly identified.

OBJECTIVE

To conduct a population-level study investigating the relationship between epilepsy and several common autoimmune diseases.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective population-based study using claims from a nationwide employer-provided health insurance plan in the United States. Participants were beneficiaries enrolled between 1999 and 2006 (N = 2 518 034).

MAIN OUTCOMES AND MEASURES

We examined the relationship between epilepsy and 12 autoimmune diseases: type 1 diabetes mellitus, psoriasis, rheumatoid arthritis, Graves disease, Hashimoto thyroiditis, Crohn disease, ulcerative colitis, systemic lupus erythematosus, antiphospholipid syndrome, Sjögren syndrome, myasthenia gravis, and celiac disease.

RESULTS

The risk of epilepsy was significantly heightened among patients with autoimmune diseases (odds ratio, 3.8; 95% CI, 3.6-4.0; P < .001) and was especially pronounced in children (5.2; 4.1-6.5; P < .001). Elevated risk was consistently observed across all 12 autoimmune diseases.

CONCLUSIONS AND RELEVANCE

Epilepsy and autoimmune disease frequently co-occur; patients with either condition should undergo surveillance for the other. The potential role of autoimmunity must be given due consideration in epilepsy so that we are not overlooking a treatable cause.

Intracellular gold nanoparticles increase neuronal excitability and aggravate seizure activity in the mouse brain

Due to their inert property, gold nanoparticles (AuNPs) have drawn considerable attention; their biological application has recently expanded to include nanomedicine and neuroscience. However, the effect of AuNPs on the bioelectrical properties of a single neuron remains unknown. Here we present the effect of AuNPs on a single neuron under physiological and pathological conditions in vitro. AuNPs were intracellularly applied to hippocampal CA1 neurons from the mouse brain. The electrophysiological property of CA1 neurons treated with 5- or 40-nm AuNPs was assessed using the whole-cell patch-clamp technique. Intracellular application of AuNPs increased both the number of action potentials (APs) and input resistance. The threshold and duration of APs and the after hyperpolarization (AHP) were decreased by the intracellular AuNPs. In addition, intracellular AuNPs elicited paroxysmal depolarizing shift-like firing patterns during sustained repetitive firings (SRF) induced by prolonged depolarization (10 sec). Furthermore, low Mg²⁺-induced epileptiform activity was aggravated by the intracellular AuNPs. In this study, we demonstrated that intracellular AuNPs alter the intrinsic properties of neurons toward increasing their excitability, and may have deleterious effects on neurons under pathological conditions, such as seizure. These results provide some considerable direction on application of AuNPs into central nervous system (CNS).

Direct lineage reprogramming of mouse fibroblasts to functional midbrain dopaminergic neuronal progenitors

The direct lineage reprogramming of somatic cells to other lineages by defined factors has led to innovative cell-fate-change approaches for providing patient-specific cells. Recent reports have demonstrated that four pluripotency factors (Oct4, Sox2, Klf4, and c-Myc) are sufficient to directly reprogram fibroblasts to other specific cells, including induced neural stem cells (iNSCs). Here, we show that mouse fibroblasts can be directly reprogrammed into midbrain dopaminergic neuronal progenitors (DPs) by temporal expression of the pluripotency factors and environment containing sonic hedgehog and fibroblast growth factor 8. Within thirteen days, self-renewing and functional induced DPs (iDPs) were generated. Interestingly, the inhibition of both Jak and Gsk3β notably enhanced the iDP reprogramming efficiency. We confirmed the functionality of the iDPs by showing that the dopaminergic neurons generated from iDPs express midbrain markers, release dopamine, and show typical electrophysiological profiles. Our results demonstrate that the pluripotency factors-mediated direct reprogramming is an invaluable strategy for supplying functional and proliferating iDPs and may be useful for other neural progenitors required for disease modeling and cell therapies for neurodegenerative disorders.

Expressions of tumor necrosis factor alpha and microRNA-155 in immature rat model of status epilepticus and children with mesial temporal lobe epilepsy

Recently, the role of inflammation has attracted great attention in the pathogenesis of mesial temporal lobe epilepsy (MTLE), and microRNAs start to emerge as promising new players in MTLE pathogenesis. In this study, we investigated the dynamic expression patterns of tumor necrosis factor alpha (TNF-α) and microRNA-155 (miR-155) in the hippocampi of an immature rat model of status epilepticus (SE) and children with MTLE. The expressions of TNF-α and miR-155 were significantly upregulated in the seizure-related acute and chronic stages of MTLE in the immature rat model and also in children with MTLE. Modulation of TNF-α expression, either by stimulation using myeloid-related protein (MRP8) or lipopolysaccharide or inhibition using lenalidomide on astrocytes, leads to similar dynamic changes in miR-155 expression. Our study is the first to focus on the dynamic expression pattern of miR-155 in the immature rat of SE lithium-pilocarpine model and children with MTLE and to detect their relationship at the astrocyte level. TNF-α and miR-155, having similar expression patterns in the three stages of MTLE development, and their relationship at the astrocyte level may suggest a direct interactive relationship during MTLE development. Therefore, modulation of the TNF-α/miR-155 axis may be a novel therapeutic target for the treatment of MTLE.