Effect of prolonged phenytoin administration on rat brain gene expression assessed by DNA microarrays

Serum biomarkers in patients with drug-resistant epilepsy: a proteomics-based analysis

Objective

To investigate the serum biomarkers in patients with drug-resistant epilepsy (DRE).

Methods

A total of 9 DRE patients and 9 controls were enrolled. Serum from DRE patients was prospectively collected and analyzed for potential serum biomarkers using TMT18-labeled proteomics. After fine quality control, bioinformatics analysis was conducted to find differentially expressed proteins. Pathway enrichment analysis identified some biological features shared by differential proteins. Protein-protein interaction (PPI) network analysis was further performed to discover the core proteins.

Results

A total of 117 serum differential proteins were found in our study, of which 44 were revised upwards and 73 downwards. The up-regulated proteins mainly include UGGT2, PDIA4, SEMG1, KIAA1191, CCT7 etc. and the down-regulated proteins mainly include ROR1, NIF3L1, ITIH4, CFP, COL11A2 etc. Pathway enrichment analysis identified that the upregulated proteins were mainly enriched in processes such as immune response, extracellular exosome, serine-type endopeptidase activity and complement and coagulation cascades, and the down-regulated proteins were enriched in signal transduction, extracellular exosome, zinc/calcium ion binding and metabolic pathways. PPI network analysis revealed that the core proteins nodes include PRDX6, CAT, PRDX2, SOD1, PARK7, GSR, TXN, ANXA1, HINT1, and S100A8 etc.

Conclusion

The discovery of these differential proteins enriched our understanding of serum biomarkers in patients with DRE and potentially provides guidance for future targeted therapy.

Autophagy and autophagy signaling in Epilepsy: possible role of autophagy activator

Autophagy is an explicit cellular process to deliver dissimilar cytoplasmic misfolded proteins, lipids and damaged organelles to the lysosomes for degradation and elimination. The mechanistic target of rapamycin (mTOR) is the main negative regulator of autophagy. The mTOR pathway is involved in regulating neurogenesis, synaptic plasticity, neuronal development and excitability. Exaggerated mTOR activity is associated with the development of temporal lobe epilepsy, genetic and acquired epilepsy, and experimental epilepsy. In particular, mTOR complex 1 (mTORC1) is mainly involved in epileptogenesis. The investigation of autophagy's involvement in epilepsy has recently been conducted, focusing on the critical role of rapamycin, an autophagy inducer, in reducing the severity of induced seizures in animal model studies. The induction of autophagy could be an innovative therapeutic strategy in managing epilepsy. Despite the protective role of autophagy against epileptogenesis and epilepsy, its role in status epilepticus (SE) is perplexing and might be beneficial or detrimental. Therefore, the present review aims to revise the possible role of autophagy in epilepsy.

Seizure-Induced Oxidative Stress in Status Epilepticus: Is Antioxidant Beneficial?

Epilepsy is a common neurological disorder which affects patients physically and mentally and causes a real burden for the patient, family and society both medically and economically. Currently, more than one-third of epilepsy patients are still under unsatisfied control, even with new anticonvulsants. Other measures may be added to those with drug-resistant epilepsy. Excessive neuronal synchronization is the hallmark of epileptic activity and prolonged epileptic discharges such as in status epilepticus can lead to various cellular events and result in neuronal damage or death. Unbalanced oxidative status is one of the early cellular events and a critical factor to determine the fate of neurons in epilepsy. To counteract excessive oxidative damage through exogenous antioxidant supplements or induction of endogenous antioxidative capability may be a reasonable approach for current anticonvulsant therapy. In this article, we will introduce the critical roles of oxidative stress and further discuss the potential use of antioxidants in this devastating disease.

A new computational drug repurposing method using established disease-drug pair knowledge

MOTIVATION

Drug repurposing is a potential alternative to the classical drug discovery pipeline. Repurposing involves finding novel indications for already approved drugs. In this work, we present a novel machine learning-based method for drug repurposing. This method explores the anti-similarity between drugs and a disease to uncover new uses for the drugs. More specifically, our proposed method takes into account three sources of information: (i) large-scale gene expression profiles corresponding to human cell lines treated with small molecules, (ii) gene expression profile of a human disease and (iii) the known relationship between Food and Drug Administration (FDA)-approved drugs and diseases. Using these data, our proposed method learns a similarity metric through a supervised machine learning-based algorithm such that a disease and its associated FDA-approved drugs have smaller distance than the other disease-drug pairs.

RESULTS

We validated our framework by showing that the proposed method incorporating distance metric learning technique can retrieve FDA-approved drugs for their approved indications. Once validated, we used our approach to identify a few strong candidates for repurposing.

AVAILABILITY AND IMPLEMENTATION

The R scripts are available on demand from the authors.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

A randomized, double-blind, placebo-controlled trial of lamotrigine for prescription corticosteroid effects on the human hippocampus

In animals, stress and corticosteroid excess are associated with decreases in memory performance and hippocampal volume that may be prevented with agents that decrease glutamate release. Humans also demonstrate changes in memory and hippocampus with corticosteroids. In this report the effects of glutamate-release inhibitor lamotrigine on hippocampal structure and memory were examined in people receiving medically needed prescription corticosteroid therapy. A total of 54 outpatient adults (n = 28 women) receiving chronic (≥ 6 months) oral corticosteroid therapy were randomized to lamotrigine or placebo for 48 weeks. Declarative memory was assessed using the Rey Auditory Verbal Learning Test (RAVLT); structural magnetic resonance imaging (MRI) as well as single-voxel proton MR spectroscopy (¹HMRS) focused on hippocampus were obtained at baseline and week 48. Utilizing a mixed-model approach, structural and biochemical data were examined by separate ANOVAs, and memory was assessed with a multi-level longitudinal model. RAVLT total scores demonstrated significantly better declarative memory performance with lamotrigine than placebo (p = 0.047). Hippocampal subfield volumes were not significantly different between the treatment groups. In summary, lamotrigine was associated with less decline in declarative memory performance than placebo in corticosteroid-treated patients. Findings suggest that, in humans as well as in animal models, glutamate release inhibitors may attenuate some of the effects on the human memory associated with corticosteroids.

Familial Risk and a Genome-Wide Supported DRD2 Variant for Schizophrenia Predict Lateral Prefrontal-Amygdala Effective Connectivity During Emotion Processing

The brain functional mechanisms translating genetic risk into emotional symptoms in schizophrenia (SCZ) may include abnormal functional integration between areas key for emotion processing, such as the amygdala and the lateral prefrontal cortex (LPFC). Indeed, investigation of these mechanisms is also complicated by emotion processing comprising different subcomponents and by disease-associated state variables. Here, our aim was to investigate the relationship between risk for SCZ and effective connectivity between the amygdala and the LPFC during different subcomponents of emotion processing. Thus, we first characterized with dynamic causal modeling (DCM) physiological patterns of LPFC-amygdala effective connectivity in healthy controls (HC) during implicit and explicit emotion processing. Then, we compared DCM patterns in a subsample of HC, in patients with SCZ and in healthy siblings of patients (SIB), matched for demographics. Finally, we investigated in HC association of LPFC-amygdala effective connectivity with a genome-wide supported variant increasing genetic risk for SCZ and possibly relevant to emotion processing (DRD2 rs2514218). In HC, we found that a "bottom-up" amygdala-to-LPFC pattern during implicit processing and a "top-down" LPFC-to-amygdala pattern during explicit processing were the most likely directional models of effective connectivity. Differently, implicit emotion processing in SIB, SCZ, and HC homozygous for the SCZ risk rs2514218 C allele was associated with decreased probability for the "bottom-up" as well as with increased probability for the "top-down" model. These findings suggest that task-specific anomaly in the directional flow of information or disconnection between the amygdala and the LPFC is a good candidate endophenotype of SCZ.

PI3Kγ deficiency enhances seizures severity and associated outcomes in a mouse model of convulsions induced by intrahippocampal injection of pilocarpine

Phosphatidylinositol 3-kinase (PI3K) is an enzyme involved in different pathophysiological processes, including neurological disorders. However, its role in seizures and postictal outcomes is still not fully understood. We investigated the role of PI3Kγ on seizures, production of neurotrophic and inflammatory mediators, expression of a marker for microglia, neuronal death and hippocampal neurogenesis in mice (WT and PI3Kγ(-/-)) subjected to intrahippocampal microinjection of pilocarpine. PI3Kγ(-/-) mice presented a more severe status epilepticus (SE) than WT mice. In hippocampal synaptosomes, genetic or pharmacological blockade of PI3Kγ enhanced the release of glutamate and the cytosolic calcium concentration induced by KCl. There was an enhanced neuronal death and a decrease in the doublecortin positive cells in the dentate gyrus of PI3Kγ(-/-) animals after the induction of SE. Levels of BDNF were significantly increased in the hippocampus of WT and PI3Kγ(-/-) mice, although in the prefrontal cortex, only PI3Kγ(-/-) animals showed significant increase in the levels of this neurotrophic factor. Pilocarpine increased hippocampal microglial immunolabeling in both groups, albeit in the prelimbic, medial and motor regions of the prefrontal cortex this increase was observed only in PI3Kγ(-/-) mice. Regarding the levels of inflammatory mediators, pilocarpine injection increased interleukin (IL) 6 in the hippocampus of WT and PI3Kγ(-/-) animals and in the prefrontal cortex of PI3Kγ(-/-) animals 24h after the stimulus. Levels of TNFα were enhanced in the hippocampus and prefrontal cortex of only PI3Kγ(-/-) mice at this time point. On the other hand, PI3Kγ deletion impaired the increase in IL-10 in the hippocampus induced by pilocarpine. In conclusion, the lack of PI3Kγ revealed a deleterious effect in an animal model of convulsions induced by pilocarpine, suggesting that this enzyme may play a protective role in seizures and pathological outcomes associated with this condition.

The effect of chronic phenytoin administration on single prolonged stress induced extinction retention deficits and glucocorticoid upregulation in the rat medial prefrontal cortex

RATIONALE

Post-traumatic stress disorder (PTSD) is a chronic, debilitating disorder. Only two pharmacological agents are approved for PTSD treatment, and they often do not address the full range of symptoms nor are they equally effective in all cases. Animal models of PTSD are critical for understanding the neurobiology involved and for identification of novel therapeutic targets. Using the rodent PTSD model, single prolonged stress (SPS), we have implicated aberrant excitatory neural transmission and glucocorticoid receptor (GR) upregulation in the medial prefrontal cortex (mPFC) and hippocampus (HPC) in fear memory abnormalities associated with PTSD.

OBJECTIVE

The objective of this study is to examine the potential protective effect of antiepileptic phenytoin (PHE) administration on SPS-induced extinction retention deficits and GR expression.

METHODS

Forty-eight SPS-treated male Sprague Dawley rats or controls were administered PHE (40, 20 mg/kg, vehicle) for 7 days following SPS stressors; then, fear conditioning, extinction, and extinction retention were tested.

RESULTS

Fear conditioning and extinction were unaffected by SPS or PHE, but SPS impaired extinction retention, and both doses of PHE rescued this impairment. Similarly, SPS increased GR expression in the mPFC and dorsal HPC, and PHE prevented SPS-induced GR upregulation in the mPFC.

CONCLUSIONS

These data demonstrate that PHE administration can prevent the development of extinction retention deficits and upregulation of GR. PHE exerts inhibitory effects on voltage-gated sodium channels and decreases excitatory neural transmission via glutamate antagonism. If glutamate hyperactivity in the days following SPS contributes to SPS-induced deficits, then these data may suggest that the glutamatergic system constitutes a target for secondary prevention.

Isolation, culture, and induced multiple differentiation of Mongolian sheep bone marrow-derived mesenchymal stem cells

The aim of this paper was to explore the optimal method of isolating, purifying, and proliferating Mongolian sheep bone marrow-derived mesenchymal stem cells (BMSCs) and their multiple differentiation potentialities. Bone marrow (BM) was punctured from ∼1-year-old sheep, and BMSCs were harvested through gradient centrifuge and adherent cultures. Analysis of the growth of the passage 1, 5, and 10 cultures revealed an S-shaped growth curve with a population doubling time of 31.2 h. Karyotyping indicated that the chromosome number in the Mongolian sheep was 2n = 54, comprising 26 pairs of autosomes and one pair of sex chromosomes (XY). RT-PCR demonstrated that OCT4, SOX2, and Nanog genes at passage 3 were positively expressed. The P3 BMSCs were cultured in vitro under inductive environments and induced into adipocytes, osteoblasts, chondrocytes, neural cells, and cardiomyocytes. Their differentiation properties were confirmed by histological staining, such as oil red, Alizarin red, hematoxylin-eosin, toluidine blue, and periodic acid schiff. RT-PCR showed that the specific genes to be induced were all expressed. This proves that the isolated cells are indeed the BMSCs and also provides valuable materials for somatic cell cloning and transgenic research.

A randomized, placebo-controlled proof-of-concept, crossover trial of phenytoin for hydrocortisone-induced declarative memory changes

BACKGROUND

Corticosteroid excess is associated with declarative memory impairment and hippocampal atrophy. These findings are clinically important because approximately 1% of the population receives prescription corticosteroids at any time, and major depressive disorder is associated with elevated cortisol levels and hippocampal atrophy. In animals, hippocampal changes with corticosteroids are blocked by phenytoin. The objective of the current study was to extend these preclinical findings to humans. We examined whether phenytoin attenuated the effects of hydrocortisone on declarative memory. Functional magnetic resonance imaging (fMRI) assessed task-related hippocampal activation.

METHODS

A randomized, double-blind, placebo-controlled, within-subject crossover study was conducted in 17 healthy adult volunteers. Participants received hydrocortisone (2.5 days), phenytoin (3.5 days), both medications together, or placebo, with 21-day washouts between conditions. Differences between treatments were estimated using a mixed-effects repeated measures analysis.

RESULTS

Fifteen participants had data from at least two treatment conditions and were used in the analysis. Basal cortisol levels negatively correlated with fMRI BOLD activation in the para-hippocampus with a similar trend observed in the hippocampus. Decrease in declarative memory with hydrocortisone was blocked with concomitant phenytoin administration. Relative to the placebo condition, a significant decrease in hippocampal BOLD activation was observed with hydrocortisone and phenytoin alone, and the two medications in combination. Declarative memory did not show significant correlations with hippocampal activation.

LIMITATIONS

The modest sample size, which limited our statistical power, was a limitation.

CONCLUSIONS

Findings from this pilot study suggest phenytoin attenuated effects of corticosteroids memory in humans, but potentiated the reduction in hippocampal activation.

Conditions to improve expansion of human mesenchymal stem cells based on rat samples

AIM

To improve the isolation and expansion of human marrow-derived mesenchymal stem cells (MSCs) based on rat samples.

METHODS

Based on the fact that rat MSCs are relatively easy to obtain from a small aspirate, bone marrow-derived MSCs from rat were cultured and characterized to set up the different protocols used in this study. Then, accordingly, almost the same protocols were performed on human healthy bone marrow samples, after obtaining approval of the ethics committee and gaining informed consent. We used different protocols and culture conditions, including the type of basal media and the culture composition. The MSCs were characterized by immunophenotyping and differentiation.

RESULTS

There was no difference in morphology and proliferation capacity between different culture media at the first passage. During the 5-7th passages, the cells gradually lost their morphology and proliferation potential on Dulbecco's modified Eagle's medium (DMEM) high glucose and α modified Eagle's medium. Although the cells expanded rapidly for up to 10 passages on DMEM low glucose containing 10% to 15% fetal calf serum (FCS), their proliferation was arrested without change in morphology and differentiation capacity at the third passage on 5% FCS. Flow cytometric analysis and functional tests confirmed that more than 90% of marrow cells which were isolated and expanded by our selective protocols were MSCs.

CONCLUSION

We improved the isolation and expansion of human bone marrow derived MSCs, based on rat sample experiments, for further experimental and clinical use.

Exploring the genomic basis of pharmacoresistance in epilepsy: an integrative analysis of large-scale gene expression profiling studies on brain tissue from epilepsy surgery

Some patients with pharmacoresistant epilepsy undergo therapeutic resection of the epileptic focus. At least 12 large-scale microarray studies on brain tissue from epilepsy surgery have been published over the last 10 years, but they have failed to make a significant impact upon our understanding of pharmacoresistance, because (1) doubts have been raised about their reproducibility, (2) only a small number of the gene expression changes found in each microarray study have been independently validated and (3) the results of different studies have not been integrated to give a coherent picture of the genetic changes involved in epilepsy pharmacoresistance. To overcome these limitations, we (1) assessed the reproducibility of the microarray studies by calculating the overlap between lists of differentially regulated genes from pairs of microarray studies and determining if this was greater than would be expected by chance alone, (2) used an inter-study cross-validation technique to simultaneously verify the expression changes of large numbers of genes and (3) used the combined results of the different microarray studies to perform an integrative analysis based on enriched gene ontology terms, networks and pathways. Using this approach, we respectively (1) demonstrate that there are statistically significant overlaps between the gene expression changes in different publications, (2) verify the differential expression of 233 genes and (3) identify the biological processes, networks and genes likely to be most important in the development of pharmacoresistant epilepsy. Our analysis provides novel biologically plausible candidate genes and pathways which warrant further investigation to assess their causal relevance.

HLA-B*1502 genotyping in two Chinese patients with phenytoin-induced Stevens-Johnson syndrome

Previous studies have reported that patients with phenytoin-induced Stevens-Johnson syndrome and toxic epidermal necrolysis (PHT-induced SJS/TEN) were positive for HLA-B*1502. We genotyped two patients with PHT-induced SJS using both polymerase chain reaction with sequence-specific primers and sequencing. The results revealed that one patient from Henan Province had HLA-B*1501/B*5401, and the other patient from Guangdong Province had HLA-B*1502/B*4601. When this information was combined with the results from Taiwan and Hong Kong, a significant difference was observed in the presence of HLA-B*1502 between PHT-SJS and PHT-tolerant populations (35% vs 8%, P=0.001, OR=6.08, 95% CI=2.183-16.946). Additional studies in large samples are required to confirm the association between HLA-B*1502 and PHT-induced SJS/TEN.