Valproic acid exposure leads to upregulation and increased promoter histone acetylation of sepiapterin reductase in a serotonergic cell line

Amygdala-hippocampal interactions in synaptic plasticity and memory formation

Memories of emotionally arousing events tend to endure longer than other memories. This review compiles findings from several decades of research investigating the role of the amygdala in modulating memories of emotional experiences. Episodic memory is a kind of declarative memory that depends upon the hippocampus, and studies suggest that the basolateral complex of the amygdala (BLA) modulates episodic memory consolidation through interactions with the hippocampus. Although many studies in rodents and imaging studies in humans indicate that the amygdala modulates memory consolidation and plasticity processes in the hippocampus, the anatomical pathways through which the amygdala affects hippocampal regions that are important for episodic memories were unresolved until recent optogenetic advances made it possible to visualize and manipulate specific BLA efferent pathways during memory consolidation. Findings indicate that the BLA influences hippocampal-dependent memories, as well as synaptic plasticity, histone modifications, gene expression, and translation of synaptic plasticity associated proteins in the hippocampus. More recent findings from optogenetic studies suggest that the BLA modulates spatial memory via projections to the medial entorhinal cortex, and that the frequency of activity in this pathway is a critical element of this modulation.

Transcriptional analysis of sodium valproate in a serotonergic cell line reveals gene regulation through both HDAC inhibition-dependent and independent mechanisms

Sodium valproate (VPA) is a histone deacetylase (HDAC) inhibitor, widely prescribed in the treatment of bipolar disorder, and yet the precise modes of therapeutic action for this drug are not fully understood. After exposure of the rat serotonergic cell line RN46A to VPA, RNA-sequencing (RNA-Seq) analysis showed widespread changes in gene expression. Analysis by four bioinformatic pipelines revealed as many as 230 genes were significantly upregulated and 72 genes were significantly downregulated. A subset of 23 differentially expressed genes was selected for validation using the nCounter® platform, and of these we obtained robust validation for ADAM23, LSP1, MAOB, MMP13, PAK3, SERPINB2, SNAP91, WNT6, and ZCCHC12. We investigated the effect of lithium on this subset and found four genes, CDKN1C, LSP1, SERPINB2, and WNT6 co-regulated by lithium and VPA. We also explored the effects of other HDAC inhibitors and the VPA analogue valpromide on the subset of 23 selected genes. Expression of eight of these genes, CDKN1C, MAOB, MMP13, NGFR, SHANK3, VGF, WNT6 and ZCCHC12, was modified by HDAC inhibition, whereas others did not appear to respond to several HDAC inhibitors tested. These results suggest VPA may regulate genes through both HDAC-dependent and independent mechanisms. Understanding the broader gene regulatory effects of VPA in this serotonergic cell model should provide insights into how this drug works and whether other HDAC inhibitor compounds may have similar gene regulatory effects, as well as highlighting molecular processes that may underlie regulation of mood.

Sepiapterin reductase: Characteristics and role in diseases

Sepiapterin reductase, a homodimer composed of two subunits, plays an important role in the biosynthesis of tetrahydrobiopterin. Furthermore, sepiapterin reductase exhibits a wide distribution in different tissues and is associated with many diseases, including brain dysfunction, chronic pain, cardiovascular disease and cancer. With regard to drugs targeting sepiapterin reductase, many compounds have been identified and provide potential methods to treat various diseases. However, the underlying mechanism of sepiapterin reductase in many biological processes is unclear. Therefore, this article summarized the structure, distribution and function of sepiapterin reductase, as well as the relationship between sepiapterin reductase and different diseases, with the aim of finding evidence to guide further studies on the molecular mechanisms and the potential clinical value of sepiapterin reductase. In particular, the different effects induced by the depletion of sepiapterin reductase or the inhibition of the enzyme suggest that the non-enzymatic activity of sepiapterin reductase could function in certain biological processes, which also provides a possible direction for sepiapterin reductase research.

Synthesis, Antibacterial Activity and Molecular Docking Studies of New Pyrazole Derivatives

Background:

The pyrazole structure is an important heterocyclic structure and plays critical roles in agriculture, industrial and medicine. Furthermore, compounds containing pyrazole are known to exhibit various biological properties such as antibacterial, antifungal, anticancer, antiinflammatory, antidepressant, antipyretic, antiviral, anti-tubercular and anti-HIV activities. Because of these properties, pyrazole molecules have become a very popular topic for organic chemists.

Methods:

A series newly substituted pyrazole molecules were synthesized and characterized. Their antimicrobial activities were investigated by disk diffusion method against some gram positive bacteria and gram negative bacteria.

Results:

The present results indicated that the some test compounds were active in a broad spectrum against important human pathogenic microorganisms. The substituted pyrazoles including carbazone (7a, b) and thiazolidine (8a, b) showed a wide variety of biological activities. The results showed that synthesized pyrazole, compounds 7b and 8b are highly active and more potent in both biological and molecular docking simulation studies.

Conclusion:

The synthesized pyrazole molecules showed moderate antibacterial activities against the tested microorganism compared to antibiotic drug. Some test compounds (7b and 8b) might be used as new antibacterial agents.

Dissecting the Epigenetic Changes Induced by Non-Antipsychotic Mood Stabilizers on Schizophrenia and Affective Disorders: A Systematic Review

BACKGROUND

Epimutations secondary to gene-environment interactions have a key role in the pathophysiology of major psychiatric disorders. In vivo and in vitro evidence suggest that mood stabilizers can potentially reverse epigenetic deregulations found in patients with schizophrenia or mood disorders through mechanisms that are not yet fully understood. However, their activity on epigenetic processes has made them a research target for therapeutic approaches.

METHODS

We conducted a comprehensive literature search of PubMed and EMBASE for studies investigating the specific epigenetic changes induced by non-antipsychotic mood stabilizers (valproate, lithium, lamotrigine, and carbamazepine) in animal models, human cell lines, or patients with schizophrenia, bipolar disorder, or major depressive disorder. Each paper was reviewed for the nature of research, the species and tissue examined, sample size, mood stabilizer, targeted gene, epigenetic changes found, and associated psychiatric disorder. Every article was appraised for quality using a modified published process and those who met a quality score of moderate or high were included.

RESULTS

A total of 2,429 records were identified; 1,956 records remained after duplicates were removed and were screened via title, abstract and keywords; 129 records were selected for full-text screening and a remaining of 38 articles were included in the qualitative synthesis. Valproate and lithium were found to induce broader epigenetic changes through different mechanisms, mainly DNA demethylation and histones acetylation. There was less literature and hence smaller effects attributable to lamotrigine and carbamazepine could be associated overall with the small number of studies on these agents. Findings were congruent across sample types.

CONCLUSIONS

An advanced understanding of the specific epigenetic changes induced by classic mood stabilizers in patients with major psychiatric disorders will facilitate personalized interventions. Further related drug discovery should target the induction of selective chromatin remodeling and gene-specific expression effects.

Gene expression effects of lithium and valproic acid in a serotonergic cell line

Valproic acid (VPA) and lithium are widely used in the treatment of bipolar disorder. However, the underlying mechanism of action of these drugs is not clearly understood. We used RNA-Seq analysis to examine the global profile of gene expression in a rat serotonergic cell line (RN46A) after exposure to these two mood stabilizer drugs. Numerous genes were differentially regulated in response to VPA (log₂ fold change ≥ 1.0; i.e., odds ratio of ≥2, at false discovery rate <5%), but only two genes ( Dynlrb2 and Cdyl2) showed significant differential regulation after exposure of the cells to lithium, with the same analysis criteria. Both of these genes were also regulated by VPA. Many of the differentially expressed genes had functions of potential relevance to mood disorders or their treatment, such as several serpin family genes (including neuroserpin), Nts (neurotensin), Maob (monoamine oxidase B), and Ap2b1, which is important for synaptic vesicle function. Pathway analysis revealed significant enrichment of Gene Ontology terms such as extracellular matrix remodeling, cell adhesion, and chemotaxis. This study in a cell line derived from the raphe nucleus has identified a range of genes and pathways that provide novel insights into potential therapeutic actions of the commonly used mood stabilizer drugs.

MGCD0103, a selective histone deacetylase inhibitor, coameliorates oligomeric Aβ25-35 -induced anxiety and cognitive deficits in a mouse model

AIMS

Recently, histone deacetylase (HDAC) inhibitors are considered a possible therapeutic strategy in Alzheimer's disease (AD). However, HDACi treatments exhibit diverse functions with unfavorable effects in AD. Thus, the development of selective HDACi without side effects is urgently needed.

METHODS

HDACi, namely, BML210, MGCD0103, PXD101, and Droxinostat, were screened in mouse hippocampal primary cultures incubated with oligomeric Aβ_25-35 (50 μmol/L). MGCD0103 was chosen for in vivo tests and was intraperitoneally injected into C57BL/6J mice (0.5 mg/kg, once per day) for 4 weeks following an intrahippocampal CA1 injection of oligomeric Aβ_25-35 . Brain samples were collected for pathological analyses after the behavioral analyses including open- field test (OFT), elevated plus maze (EPM), Y-maze, and Morris water maze (MWM).

RESULTS

Among the HDACi, MGCD0103 exhibited significant neuroprotection against the Aβ toxicity in primary cultures. MGCD0103 coattenuated cognitive deficits and anxiety against Aβ damage in mice. MGCD0103 further ameliorated pathological features such as the levels of acetylated histone 3 at Lys 9 site (H3K9) and α-tubulin, synaptophysin, Aβ, tau protein phosphorylation, and serotonergic neuron loss against Aβ toxicity. Furthermore, chronic MGCD0103 treatment did not show liver or kidney toxicity in mice.

CONCLUSIONS

These results reveal MGCD0103 could be a potential therapeutic agent against AD.

Epigenetic Drugs for Mood Disorders

There is increasing evidence that changes in epigenetic mechanisms of gene expression are involved in the pathogenesis of mood disorders. Such evidence stems from studies conducted on postmortem brain tissues and peripheral cells or tissues of patients with mood disorders. This article describes and discusses the epigenetic changes in the mood disorders (major depressive disorder and bipolar disorder) found to date. The article also describes and discusses preclinical drug trials of epigenetic drugs for treating mood disorders. In addition, nonrandomized and randomized controlled trials of nutritional drugs with effects on epigenetic mechanisms of gene expression in patients with major depressive disorder and bipolar disorder are discussed. Trials of epigenetic drugs and nutritional drugs with epigenetic effects are showing promising results for the treatment of mood disorders. Thus, epigenetic drugs and nutritional drugs with epigenetic effects could be useful in the treatment of patients with these disorders.

Valproate increases dopamine transporter expression through histone acetylation and enhanced promoter binding of Nurr1

The dopamine transporter (DAT) is the key regulator of dopaminergic transmission and is a target of several xenobiotics, including pesticides and pharmacological agents. Previously, we identified a prominent role for histone deacetylases in the regulation of DAT expression. Here, we utilized a rat dopaminergic cell line (N27) to probe the responsiveness of DAT mRNA expression to inhibitors of histone acetylation. Inhibition of histone deacetylases (HDACs) by valproate, butyrate and Trichostatin A led to a 3-10-fold increase in DAT mRNA expression, a 50% increase in protein levels, which were accompanied by increased H3 acetylation levels. To confirm the mechanism of valproate-mediated increase in DAT mRNA, chromatin immunoprecipitation (ChIP) assays were used and demonstrated a significant increase in enrichment of acetylation of histone 3 on lysines 9 and 14 (H3K9/K14ac) in the DAT promoter. Expression of Nurr1 and Pitx3, key regulators of DAT expression, were increased following valproate treatment and Nurr1 binding was enriched in the DAT promoter. Together, these results indicate that histone acetylation and subsequent enhancement of transcription factor binding are plausible mechanisms for DAT regulation by valproate and, perhaps, by other xenobiotics.

Is the molecular clock ticking differently in bipolar disorder? Methylation analysis of the clock gene ARNTL

OBJECTIVES

The clock gene ARNTL is associated with the transcription activation of monoamine oxidase A according to previous literature. Thus, we hypothesised that methylation of ARNTL may differ between bipolar disorder (BD) and controls.

METHODS

The methylation status of one CpG island covering the first exon of ARNTL (PS2) and one site in the 5' region of ARNTL (cg05733463) were analysed in patients with BD (n = 151) versus controls (n = 66). Methylation analysis was performed by bisulphite-conversion of DNA from fasting blood with the EpiTect Bisulfite Kit, PCR and pyrosequencing. Analysis of covariances considering the covariates age, body mass index, sex, smoking, lithium and anticonvulsant intake were performed to test methylation differences between BD and controls.

RESULTS

Methylation at cg05733463 of ARNTL was significantly higher in BD than in controls (F(1,209) = 44.500, P < .001). In contrast, methylation was significantly lower in BD at PS2_POS1 compared to controls (F(1,128) = 5.787, P = .018) and by trend at PS2_POS2 (F(1,128) = 3.033, P = .084) and POS7 (F(1,34) = 3.425, P = .073).

CONCLUSIONS

Methylation of ARNTL differed significantly between BD and controls. Thus, our study suggests that altered epigenetic regulation of ARNTL might provide a mechanistic basis for better understanding circadian rhythms and mood swings in BD.

Epigenetic Downregulation of Scn3a Expression by Valproate: a Possible Role in Its Anticonvulsant Activity

Upregulation of sodium channel SCN3A expression in epileptic tissues is known to contribute to enhancing neuronal excitability and the development of epilepsy. Therefore, certain strategies to reduce SCN3A expression may be helpful for seizure control. Here, we reveal a novel role of valproate (VPA) in the epigenetic downregulation of Scn3a expression. We found that VPA, instead of carbamazepine (CBZ) and lamotrigine (LTG), could significantly downregulate Scn3a expression in mouse Neuro-2a cells. Luciferase assays and CpG methylation analyses showed that VPA induced the methylation at the -39C site in Scn3a promoter which decreased the promoter activity. We further showed that VPA downregulated the expression of methyl-CpG-binding domain protein 2 (MBD2) at the posttranscriptional level and knockdown of MBD2 increased Scn3a expression. In addition, we found that VPA induced the expression of fat mass and obesity-associated (FTO) protein and FTO knockdown abolished the repressive effects of VPA on MBD2 and Na_v1.3 expressions. Furthermore, VPA, instead of other two anticonvulsant drugs, induced the expressions of Scn3a and Mbd2 and reduced Fto expression in the hippocampus of VPA-treated seizure mice. Taken together, this study suggests an epigenetic pathway for the VPA-induced downregulation of Scn3a expression, which provides a possible role of this pathway in the anticonvulsant action of VPA.