Down-regulation of adenylate kinase 5 in temporal lobe epilepsy patients and rat model

Low Adenylate Kinase 5 expression is predictive of poor prognosis and promotes tumor growth by regulating the cell cycle pathway

Colon adenocarcinoma (COAD) is one of the most common malignant tumors of the digestive system. Specific molecular markers play important role in COAD diagnosis and therapy. Adenylate Kinase 5 (AK5) is an enzyme that is related to energy metabolism and cancer. However, the exact role of AK5 in the progression of COAD is still unclear. In this study, the expression of AK5 in tissue samples and non-cancerous tissues of COAD patients was assessed by the bioinformatics method and western blot. Kaplan-Meier survival analysis and Cox regression analysis evaluated the prognostic significance of AK5. The biological function of AK5 in tumor progression was assessed by MTT assay, colony formation assay, transwell assay, wound healing assay, western blot, and mice xenograft models. The results showed that AK5 expression in tumor tissues was lower than in non-cancerous tissues. Notably, the patients with high AK5 expression possessed a longer overall survival (OS) than the low expression patients. And low AK5 expression promoted proliferation and metastasis in COAD cells by regulating the cell cycle pathway. Importantly, in vivo results showed that reduced AK5 expression is required for tumor growth. This study confirmed the significant role of AK5 in the development and progression of COAD. Therefore, low AK5 expression levels can be an independent prognostic biomarker, which provides new sight for the clinical diagnosis and target therapy of COAD. This article is protected by copyright. All rights reserved.

Differential DNA Methylation Profiles in Patients with Temporal Lobe Epilepsy and Hippocampal Sclerosis ILAE Type I

Hippocampal sclerosis (HS) is one of the most prevalent pathological types of temporal lobe epilepsy (TLE), and it significantly affects patient prognoses. The methylation of DNA plays an important role in the development of epilepsy. However, few studies have focused on HS subtypes to determine DNA methylation profiles in TLE. This study aimed to determine the pathogenesis of TLE from an epigenetic perspective in patients with TLE-HS type I (TLE-HSTI) and TLE without HS (TLE-nHS) using whole-genome bisulfite sequencing (WGBS). We defined 1171 hypermethylated and 2537 hypomethylated regions and found 632 differentially methylated genes (DMG) in the promoter region that were primarily involved in the regulation of various aspects of epilepsy development. Twelve DMG overlapped with differentially expressed genes (DEG) in the promoter region, and RT-qPCR findings revealed significant overexpression of the SBNO2, CBX3, RASAL3, and TMBIM4 genes in TLE-HSTI. We present the first systematic analysis of methylation profiles of TLE-HSTI and TLE-nHS from an epigenetic perspective using WGBS. Overall, our preliminary data highlight the underlying mechanism of TLE-HSTI, providing a new perspective for guiding treatment of TLE.

Insights into Potential Targets for Therapeutic Intervention in Epilepsy

Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.

Aberrant energy metabolism and redox balance in seizure onset zones of epileptic patients

Epilepsy is a disorder that affects around 1% of the population. Approximately one third of patients do not respond to anti-convulsant drugs treatment. To understand the underlying biological processes involved in drug resistant epilepsy (DRE), a combination of proteomics strategies was used to compare molecular differences and enzymatic activities in tissue implicated in seizure onset to tissue with no abnormal activity within patients. Label free quantitation identified 17 proteins with altered abundance in the seizure onset zone as compared to tissue with normal activity. Assessment of oxidative protein damage by protein carbonylation identified additional 11 proteins with potentially altered function in the seizure onset zone. Pathway analysis revealed that most of the affected proteins are involved in energy metabolism and redox balance. Further, enzymatic assays showed significantly decreased activity of transketolase indicating a disruption of the Pentose Phosphate Pathway and diversion of intermediates into purine metabolic pathway, resulting in the generation of the potentially pro-convulsant metabolites. Altogether, these findings suggest that imbalance in energy metabolism and redox balance, pathways critical to proper neuronal function, play important roles in neuronal network hyperexcitability and can be used as a primary target for potential therapeutic strategies to combat DRE. SIGNIFICANCE: Epileptic seizures are some of the most difficult to treat neurological disorders. Up to 40% of patients with epilepsy are resistant to first- and second-line anticonvulsant therapy, a condition that has been classified as refractory epilepsy. One potential therapy for this patient population is the ketogenic diet (KD), which has been proven effective against multiple refractory seizure types However, compliance with the KD is extremely difficult, and carries severe risks, including ketoacidosis, renal failure, and dangerous electrolyte imbalances. Therefore, identification of pathways disruptions or shortages can potentially uncover cellular targets for anticonvulsants, leading to a personalized treatment approach depending on a patient's individual metabolic signature.

Identification of adenylate kinase 5 antibodies during routine diagnostics in a tissue-based assay: Three new cases and a review of the literature

Antibodies against adenylate kinase 5 (AK5) have been described in patients with non-paraneoplastic limbic encephalitis, mainly in men around 70 years of age. Routine testing with specific cell-based assays is not yet available. Three patients with episodic anterograde memory problems and depression had extensive limbic lesions and developed severe atrophy, mainly of the medial temporal lobes. The antibodies were identified in serum and CSF based on the typical staining pattern of AK5 antibodies on a tissue-based assay (here, unfixed mouse brain). Subsequently, they were confirmed by a research laboratory through a cell-based assay.

Identification of time‑series differentially expressed genes and pathways associated with heart failure post‑myocardial infarction using integrated bioinformatics analysis

Heart failure (HF) secondary to acute myocardial infarction (AMI) is a public health concern. The current study aimed to investigate differentially expressed genes (DEGs) and their possible function in HF post-myocardial infarction. The GSE59867 dataset included microarray data from peripheral blood samples obtained from HF and non-HF patients following AMI at 4 time points (admission, discharge, and 1 and 6 months post-AMI). Time-series DEGs were analyzed using R Bioconductor. Functional enrichment analysis was performed, followed by analysis of protein-protein interactions (PPIs). A total of 108 DEGs on admission, 32 DEGs on discharge, 41 DEGs at 1 month post-AMI and 19 DEGs at 6 months post-AMI were identified. Among these DEGs, 4 genes were downregulated at all the 4 time points. These included fatty acid desaturase 2, leucine rich repeat neuronal protein 3, G-protein coupled receptor 15 and adenylate kinase 5. Functional enrichment analysis revealed that these DEGs were mainly enriched in ‘inflammatory response’, ‘immune response’, ‘toll-like receptor signaling pathway’ and ‘NF-κβ signaling pathway’. Furthermore, PPI network analysis revealed that C-X-C motif chemokine ligand 8 and interleukin 1β were hub genes. The current study identified candidate DEGs and pathways that may serve important roles in the development of HF following AMI. The results obtained in the current study may guide the development of novel therapeutic agents for HF following AMI.

A Genome-Wide Search for Bipolar Disorder Risk Loci Modified by Mitochondrial Genome Variation

Mitochondrial DNA mutations have been reported to be associated with bipolar disorder (BD). In this study, we performed genome-wide analyses to assess mitochondrial single-nucleotide polymorphism (mtSNP) effects on BD risk and early-onset BD (EOBD) among BD patients, focusing on interaction effects between nuclear SNPs (nSNPs) and mtSNPs. Common nSNP and mtSNP data from European American BD cases (n = 1,001) and controls (n = 1,034) from the Genetic Association Information Network BD study were analyzed to assess the joint effect of nSNP and nSNP-mtSNP interaction on the risk of BD and EOBD. The effect of nSNP-mtSNP interactions was also assessed. For BD risk, the strongest evidence of an association was obtained for nSNP rs1880924 in MGAM and mtSNP rs3088309 in CytB (p_joint = 8.2 × 10^-8, p_int = 1.4 × 10^-4). Our results also suggest that the minor allele of the nSNP rs583990 in CTNNA2 increases the risk of EOBD among carriers of the mtSNP rs3088309 minor allele, while the nSNP has no effect among those carrying the mtSNP major allele (OR = 4.53 vs. 1.05, p_joint = 2.1 × 10^-7, p_int = 1.16 × 10^-6). While our results are not statistically significant after multiple testing correction and a large-sample replication is required, our exploratory study demonstrates the potential importance of considering the mitochondrial genome for identifying genetic factors associated with BD.

Down-regulation of Pin1 in Temporal Lobe Epilepsy Patients and Mouse Model

Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) is a unique PPIase belonging to the parvulin family, and it isomerizes peptide bond between phospho-(Ser/Thr) and Pro. Pin1 has been linked to the pathogenesis of various human diseases; however, its exact biological functions remain unclear. The aim of the present study is to explore the expression pattern of Pin1 in patients with refractory epilepsy and in a chronic pilocarpine-induced epileptic mouse model. Using Western blot, immunofluorescence and immunoprecipitation analysis, we found that Pin1 protein was mainly distributed in neurons, demonstrated by colocalization with the dendritic marker, MAP2. However, the expression of Pin1 decreased remarkably in epileptic patients and experimental mice. Furthermore, the reciprocal coimmunoprecipitation analysis showed that Pin1 interacted with NR2A and NR2B-containing NMDA receptors not AMPA receptors in epileptic mouse models. Our results are the first to indicate that the expression of Pin1 in epileptic brain tissue could play important roles in epilepsy.

NR4A1 Knockdown Suppresses Seizure Activity by Regulating Surface Expression of NR2B

Nuclear receptor subfamily 4 group A member 1 (NR4A1), a downstream target of CREB that is a key regulator of epileptogenesis, has been implicated in a variety of biological processes and was previously identified as a seizure-associated molecule. However, the relationship between NR4A1 and epileptogenesis remains unclear. Here, we showed that NR4A1 protein was predominantly expressed in neurons and up-regulated in patients with epilepsy as well as pilocarpine-induced mouse epileptic models. NR4A1 knockdown by lentivirus transfection (lenti-shNR4A1) alleviated seizure severity and prolonged onset latency in mouse models. Moreover, reciprocal coimmunoprecipitation of NR4A1 and NR2B demonstrated their interaction. Furthermore, the expression of p-NR2B (Tyr1472) in epileptic mice and the expression of NR2B in the postsynaptic density (PSD) were significantly reduced in the lenti-shNR4A1 group, indicating that NR4A1 knockdown partly decreased surface NR2B by promoting NR2B internalization. These results are the first to indicate that the expression of NR4A1 in epileptic brain tissues may provide new insights into the molecular mechanisms underlying epilepsy.