Fluoxetine-induced up-regulation of 14-3-3zeta and tryptophan hydroxylase levels in RBL-2H3 cells

The Influence of Fluoxetine on the Sensorimotor Function of the Sciatic Nerve in Wistar Rats after Axonotmesis: An Experimental Animal Model

BACKGROUND

Fluoxetine, a serotonin reuptake inhibitor antidepressant, raises extracellular serotonin levels and promotes angiogenesis and neurogenesis. Numerous animal models have shown its beneficial effects on recovery from peripheral nerve injury.

PURPOSE

The primary objective of this study was to analyze the influence of fluoxetine on the sensory-motor function recovery of the sciatic nerve in Wistar rats after axonotmesis.

STUDY DESIGN, SETTING, AND SAMPLE

This study utilized an experimental rat model, conducted in the laboratory at the Federal University of Pernambuco. The sample consisted of 40 male Wistar rats.

PREDICTOR VARIABLE

The primary predictor variable was the fluoxetine exposure. The animals were randomly divided into 4 groups (control and 3 experimental groups), with 10 animals in each group. They were injected subcutaneously with saline or fluoxetine 5, 10, and 20 mg/kg/day, respectively.

MAIN OUTCOME VARIABLES

The main outcome variables were postoperative motor and sensory sciatic nerve function. Sensory nerve function was measured using the withdrawal reflex by thermostimulation. Motor nerve function was measured using the Sciatic Nerve Recovery Index and the Static Sciatic Nerve Index (SSI).

COVARIATES

None.

ANALYSES

Descriptive statistical analysis was performed using mean and SD. Analaysis of variance (ANOVA) was used for comparisons between the groups and Dunnett's multiple comparisons test was used in case of significant differences between the groups. Statistical Analysis System was the software used for statistical analyses.

RESULTS

During the study, 15 animals were lost (3 in the control group and 4 in each experimental group), with no specific cause identified. On day 35, the latency time of the withdrawal reflex was significantly different, with decreased pain perception in the 5 mg/kg/day fluoxetine group (3.80 ± 1.20, P < .05). On day 14, the Sciatic Nerve Recovery Index showed greater deficits in the l0 and 20 mg/kg/day groups (-65.67 ± 7.20 and -63.57 ± 11.59, respectively) compared to the control group (P < .05). The SSI also showed a delay in recovery with the 10 mg/kg/day dose (-62.50 ± 6.72, P < .05).

CONCLUSION

The daily treatment with fluoxetine failed to bring any improvement to motor or sensory recuperation after injury to the sciatic nerve in Wistar rats.

SERT and OCT mediate 5-HT1B receptor regulation of immobility behavior and uptake of 5-HT and HIS

5-HT clearance, commonly mediated by transporters in the uptake-1 and uptake-2 families, has been linked to 5-HT1B receptor's action on behaviors. Since no specific transporters identified yet, effects of serotonin transporter (SERT) and organic cation transporter (OCTs) on 5-HT1B-elicited immobility phenotype, and 5-HT and HIS uptake were then investigated. Intraperitoneal injections of SERT inhibitor fluoxetine (FLX) and/or OCTs inhibitor decynium (D22) were used prior to local perfusion of 5-HT1B agonist CP93129 into the ventral hippocampus to measure immobility times in the FST and TST, to measure 5-HT uptake efficiencies and HIS uptake efficiencies derived from linear regressions using the transient no-net-flux quantitative microdialysis in C57BL/6 mice. Exogenous 5-HT and HIS uptake were measured following incubation of FLX and/or D22 with CP93129 in the RBL-2H3 cells. Moreover, surface membrane levels of SERT and OCT were detected in response to CP93129. Local CP93129 prolonged immobility times, which were attenuated following pretreatment of either inhibitor. Local CP93129 lowered the slopes obtained from the lineal regressions for 5-HT and HIS (slope is reciprocal to uptake efficiency), which were then weakened following pretreatment of either inhibitor. Similar findings were obtained following CP93129 incubation, and co-incubation of CP93129 with either inhibitor in the RBL-2H3. Moreover, CP93129 dose-dependently moved SERT and OCT3 in the cytosol to the surface membrane. Both SERT and OCT are the target effectors mediating 5-HT1B regulation of immobility time and 5-HT uptake, OCT mediates 5-HT1B regulation of HIS uptake. Their underlying signal transductions need to be further explored.

Luteolin suppresses 5-hydroxytryptamine elevation in stimulated RBL-2H3 cells and experimental colitis mice

Increased 5-hydroxytryptamine may be associated with the development and progression of inflammatory bowel disease. In this study, we examined the suppressive effect of flavonoids on the increased intra- and extracellular 5-hydroxytryptamine levels in rat mast RBL-2H3 cells, known to produce 5-hydroxytryptamine by the phorbol 12-myristate 13-acetate stimulation. Among the flavonoids examined, luteolin and quercetin significantly reduced the cellular 5-hydroxytryptamine concentration. Gene and protein expression analyses revealed that luteolin significantly suppressed cellular tryptophan hydroxylase 1 expression induced by phorbol 12-myristate 13-acetate stimulation. Mitogen-activated protein kinase/extracellular signal-regulated kinase signaling was also suppressed by luteolin, suggesting that this pathway is one of targets of 5-hydroxytryptamine modulation by luteolin. An in vivo experimental colitis model was prepared by administering 2.5% dextran sodium sulfate in drinking water to C57BL/6 mice for seven days. The ingestion of 0.1% dietary luteolin suppressed the increasing 5-hydroxytryptamine in the colorectal mucosa. In conclusion, luteolin possesses a suppressive effect on extensive 5-hydroxytryptamine formation in both experimental RBL-2H3 cells and colitis models.

Fluoxetine-induced hepatic lipid accumulation is linked to elevated serotonin production

Fluoxetine, a commonly prescribed selective serotonin reuptake inhibitor antidepressant, has been shown to increase hepatic lipid accumulation, a key factor in the development of nonalcoholic fatty liver disease. Interestingly, fluoxetine has also been reported to increase peripheral serotonin synthesis. As emerging evidence suggests that serotonin may be involved in the development of nonalcoholic fatty liver disease, we sought to determine if fluoxetine-induced hepatic lipid accumulation is mediated via altered serotonin production. Fluoxetine treatment increased lipid accumulation in association with increased mRNA expression of tryptophan hydroxylase 1 (Tph1, serotonin biosynthetic enzyme) and intracellular serotonin content. Serotonin alone had a similar effect to increase lipid accumulation. Moreover, blocking serotonin synthesis reversed the fluoxetine-induced increases in lipid accumulation. Collectively, these data suggest that fluoxetine-induced lipid accumulation can be mediated, in part, by elevated serotonin production. These results suggest a potential therapeutic target to ameliorate the adverse metabolic effects of fluoxetine exposure.

Serotonin and serotonin reuptake inhibitors alter placental aromatase

Serotonin reuptake inhibitors (SRIs) are currently the main molecules prescribed to pregnant women that suffer from depression. Placental cells are exposed to SRIs via maternal blood, and we have previously shown that SRIs alter feto-placental steroidogenesis in an in vitro co-culture model. More specifically, serotonin (5-HT) regulates the estrogen biosynthetic enzyme aromatase (cytochrome P450 19; CYP19), which is disrupted by fluoxetine and its active metabolite norfluoxetine in BeWo choriocarcinoma cells. Based on molecular simulations, the present study illustrates that the SRIs fluoxetine, norfluoxetine, paroxetine, sertraline, citalopram and venlafaxine exhibit binding affinity for the active-site pocket of CYP19, suggesting potential competitive inhibition. Using BeWo cells and primary villous trophoblast cells isolated from normal term placentas, we compared the effects of the SRIs on CYP19 activity. We observed that paroxetine and sertraline induce aromatase activity in BeWo cells, while venlafaxine, fluoxetine, paroxetine and sertraline decrease aromatase activity in primary villous trophoblast. The effects of paroxetine and sertraline in primary villous trophoblasts were observed at the lower doses tested. We also showed that 5-HT and the 5-HT_2A receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) induced CYP19 activity. An increase in phosphorylation of serine and tyrosine and a decrease in threonine phosphorylation of CYP19 was also associated with DOI treatment. Our results contribute to better understanding how 5-HT and SRIs interact with CYP19 and may affect estrogen production. Moreover, this study suggests that alteration of placental 5-HT levels due to depression and/or SRI treatment during pregnancy may be associated with disruption of placental estrogen production.

Deletion of a putative NlpC/P60 endopeptidase BAS1812 affects germination, long-term survival and endospore formation in Bacillus anthracis

Bacillus anthracis, an aetiologic agent of the zoonotic disease anthrax, encodes a putative NlpC/P60 endopeptidase BAS1812. It harbours a signal peptide, three bacterial SH3 domains and an NlpC/P60 family domain. Previous studies showed that BAS1812 is immunogenic in infected hosts and is a potential biomarker for anthrax treatment. To date, however, little information is known about its function and involvement in anthrax pathogenesis. Here we describe the phenotypic effect of BAS1812 deletion in B. anthracis Sterne strain. Transcriptional analysis showed that BAS1812 expression in a host-like environment was enhanced at the end of log phase, started to diminish after entry to stationary phase and increased again late in stationary phase. The constructed BAS1812 mutant showed impaired long-term survival in the stationary growth phase, less resilience to detergent, lesser endospore formation and delayed germination. The mutant also showed diminished ability to degrade peptidoglycan, but its ability to produce anthrax exotoxins was not affected. We hypothesize that BAS1812 is a cell wall hydrolase involved in biological activities related to maintaining cell wall integrity, sporulation and spore germination.

Whole-genome expression analysis reveals genes associated with treatment response to escitalopram in major depression

The reasons for variability in treatment response in major depressive disorder (MDD) are not fully understood, but there is accumulating evidence suggesting that therapeutic outcomes of antidepressants can be influenced by genetic factors. In the present study we applied the microarray Illumina platform for whole genome expression profiling in depressive patients treated with escitalopram medication in order to identify genes underlying response to antidepressant treatment. The initial study sample consisted of 135 outpatients with major depressive disorder (mean age 31.1±11.6 years, 68% females) treated with escitalopram 10-20mg/day for 12 weeks, from which 87 patients (55 females) were included in gene expression analyzing. The gene expression profiles were measured on peripheral blood cells at baseline, at week 4 and at the end of treatment (week 12) using BeadChips Illumina. The fold change was used to demonstrate rate of changes in average gene expressions between studied groups. Statistical analyses were performed using the false discovery rate (FDR). The most interesting gene, which showed the predictive effect on treatment outcome by delineating low dose responders and treatment-resistant patients at the beginning of medication, was NLGN2, belonging to a family of neuronal cell surface proteins and involving in synapse formation. In addition, the several gene clusters, related to immune response, signal transduction and neurotrophin pathway, have distinguished responders from non-responders at the week 4 of treatment. After 4 weeks of escitalopram treatment (10mg/day), the YWHAZ gene has showed the highest transcriptional change in responders as compared with non-responders. Finally, at the end of the treatment we noticed that at least three genes (NR2C2, ZNF641, FKBP1A) have been strongly associated with resistance to escitalopram. Thus the results of this study support that exploration of peripheral gene expression is a useful tool in the further identification of novel genetic biomarkers for antidepressant treatment response.

Changes in Bacillus anthracis CodY regulation under host-specific environmental factor deprived conditions

Background

Host-specific environmental factors induce changes in Bacillus anthracis gene transcription during infection. A global transcription regulator, CodY, plays a pivotal role in regulating central metabolism, biosynthesis, and virulence in B. anthracis. In this study, we utilized RNA-sequencing to assess changes in the transcriptional patterns of CodY-regulated B. anthracis genes in response to three conditions of environmental starvation: iron, CO₂, or glucose deprivation. In addition, we performed chromatin immunoprecipitation on newly identified CodY-mediated genes.

Results

Environmental deprivation induced transcriptional changes in CodY-regulated genes in both wild-type and codY null strains, and both CodY-specific and environment-specific patterns were observed. In the iron-depleted condition, overexpression of iron homeostasis genes was observed independent of codY deletion; however, transcription of siderophore and amino acid biosynthesis genes was CodY dependent. Although CodY has a significant regulatory role in central metabolism and the carbon overflow pathway, metabolism-associated genes exhibited CodY-independent expression patterns under glucose starvation. Genes that were differentially expressed in response to CO₂ availability showed CodY-dependent regulation, though their maximal expression did require a supply of CO₂/bicarbonate.

Conclusions

We speculate that CodY regulates the expression of environmental-responsive genes in a hierarchical manner and is likely associated with other transcription regulators that are specific for a particular environmental change.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3004-8) contains supplementary material, which is available to authorized users.

Late-Exponential Gene Expression in codY-Deficient Bacillus anthracis in a Host-Like Environment

CodY is a pleiotropic regulator commonly found in Gram-positive bacteria and regulates various biological processes during the stringent response in a nutrient-limiting environment. CodY also participates in virulence factor expression in many low G+C Gram-positive pathogens, as observed in Bacillus anthracis. However, the mechanism by which B. anthracis CodY regulates metabolism and virulence factors in response to environmental changes is unclear. Here, we attempted to identify the link between CodY and B. anthracis regulation with codY-deficient and codY-overexpressing mutants using high-throughput transcriptional analysis. Growth pattern analyses of codY mutants in both rich and minimal media showed defects in early cell proliferation, with opposite patterns in the early stationary phase: CodY overexpression prolonged bacterial growth, whereas deletion inhibited growth. RNA sequencing of codY-deficient B. anthracis showed both positive and negative changes in the gene expression of proteases and virulence factors as well as genes related to stringent response-related metabolism and biosynthetic processing. We also found that changes in codY expression could alter virulence gene expression of B. anthracis, suggesting modes of regulation in its virulence in a CodY concentration-dependent manner. Collectively, we conclude from these results that CodY can both positively and negatively regulate its regulon via direct and/or indirect approaches, and that its mode of regulation may be concentration dependent.

Ursolic acid derivatives as bone anabolic agents targeted to tryptophan hydroxylase 1 (Tph-1)

Tryptophan hydroxylase 1 (Tph-1) initiates the biosynthesis of peripheral serotonin. As peripheral serotonin suppresses bone formation, inhibitor of Tph-1 provides a useful tool to discover anabolic agents for osteoporosis. In the present study, series of ursolic acid (UA) derivatives were synthesized, and their inhibitory activity on serotonin biosynthesis and cytotoxicity were evaluated. Among the derivatives, 8d with potent inhibitory activity on serotonin was applied for further research. The data revealed that 8d significantly inhibited protein and mRNA expressions of Tph-1, and an SPR study indicated that 8d directly interacted to Tph-1 with a binding affinity of KD=15.09μM. Oral administration of 8d significantly prevented bone loss via suppressing serotonin biosynthesis without estrogenic side-effects in ovariectomized (OVX) rats.

Profiling of Proteins Regulated by Venlafaxine during Neural Differentiation of Human Cells

OBJECTIVE

Antidepressants are known to positively influence several factors in patients with depressive disorders, resulting in increased neurogenesis and subsequent relief of depressive disorders. To study the effects of venlafaxine during neural differentiation at the cellular level, we looked at its effect on protein expression and regulation mechanisms during neural differentiation.

METHODS

After exposing NCCIT cell-derived EBs to venlafaxine during differentiation (1 day and 7 days), changes in protein expression were analyzed by 2-DE and MALDI-TOF MS analysis. Gene levels of proteins regulated by venlafaxine were analyzed by real-time RT-PCR.

RESULTS

Treatment with venlafaxine decreased expression of prolyl 4-hydroxylase (P4HB), ubiquitin-conjugating enzyme E2K (HIP2) and plastin 3 (T-plastin), and up-regulated expression of growth factor beta-3 (TGF-β3), dihydropyrimidinase-like 3 (DPYSL3), and pyruvate kinase (PKM) after differentiation for 1 and 7 days. In cells exposed to venlafaxine, the mRNA expression patterns of HIP2 and PKM, which function as negative and positive regulators of differentiation and neuronal survival, respectively, were consistent with the observed changes in protein expression.

CONCLUSION

Our findings may contribute to improve understanding of molecular mechanism of venlafaxine.

Gene expression changes for antioxidants pathways in the mouse cochlea: relations to age-related hearing deficits

Age-related hearing loss - presbycusis - is the number one neurodegenerative disorder and top communication deficit of our aged population. Like many aging disorders of the nervous system, damage from free radicals linked to production of reactive oxygen and/or nitrogen species (ROS and RNS, respectively) may play key roles in disease progression. The efficacy of the antioxidant systems, e.g., glutathione and thioredoxin, is an important factor in pathophysiology of the aging nervous system. In this investigation, relations between the expression of antioxidant-related genes in the auditory portion of the inner ear - cochlea, and age-related hearing loss was explored for CBA/CaJ mice. Forty mice were classified into four groups according to age and degree of hearing loss. Cochlear mRNA samples were collected and cDNA generated. Using Affymetrix® GeneChip, the expressions of 56 antioxidant-related gene probes were analyzed to estimate the differences in gene expression between the four subject groups. The expression of Glutathione peroxidase 6, Gpx6; Thioredoxin reductase 1, Txnrd1; Isocitrate dehydrogenase 1, Idh1; and Heat shock protein 1, Hspb1; were significantly different, or showed large fold-change differences between subject groups. The Gpx6, Txnrd1 and Hspb1 gene expression changes were validated using qPCR. The Gpx6 gene was upregulated while the Txnrd1 gene was downregulated with age/hearing loss. The Hspb1 gene was found to be downregulated in middle-aged animals as well as those with mild presbycusis, whereas it was upregulated in those with severe presbycusis. These results facilitate development of future interventions to predict, prevent or slow down the progression of presbycusis.

Serotonin: a novel bone mass controller may have implications for alveolar bone

As recent studies highlight the importance of alternative mechanisms in the control of bone turnover, new therapeutic approaches can be envisaged for bone diseases and periodontitis-induced bone loss. Recently, it has been shown that Fluoxetine and Venlafaxine, serotonin re-uptake inhibitors commonly used as antidepressants, can positively or negatively affect bone loss in rat models of induced periodontitis. Serotonin is a neurotransmitter that can be found within specific nuclei of the central nervous system, but can also be produced in the gut and be sequestered inside platelet granules. Although it is known to be mainly involved in the control of mood, sleep, and intestinal physiology, recent evidence has pointed at far reaching effects on bone metabolism, as a mediator of the effects of Lrp5, a membrane receptor commonly associated with Wnt canonical signaling and osteoblast differentiation. Deletion of Lrp5 in mice lead to increased expression of Tryptophan Hydroxylase 1, the gut isoform of the enzyme required for serotonin synthesis, thus increasing serum levels of serotonin. Serotonin, in turn, could bind to HTR1B receptors on osteoblasts and stop their proliferation by activating PKA and CREB.

Although different groups have reported controversial results on the existence of an Lrp5-serotonin axis and the action of serotonin in bone remodeling, there is convincing evidence that serotonin modulators such as SSRIs can affect bone turnover. Consequently, the effects of this drug family on periodontal physiology should be thoroughly explored.

Effects of the monoamine oxidase inhibitors pargyline and tranylcypromine on cellular proliferation in human prostate cancer cells

Chemotherapy is one of the therapeutic strategies that has been used for the inhibition of cancer cell proliferation in several types of cancer, including prostate cancer. Although monoamine oxidase (MAO) inhibitors, phytoestrogen and antioxidants used in chemotherapy have been systematically studied, their effects on cancer cell growth remain to be fully understood. The purpose of this study was to investigate the effects of the MAO inhibitors, pargyline and tranylcypromine on cell survival in human prostate carcinoma (LNCaP-LN3) cells. After treating LNCaP-LN3 cells with pargyline or tranylcypromine, we examined cell proliferation, cell cycle pattern, apoptosis and the expression levels of apoptosis-related genes. The proliferation of cells exposed to pargyline decreased in a dose- and time-dependent manner, while tranylcypromine-treated cells showed the opposite results. Treatment with pargyline significantly induced cell cycle arrest at the G1 phase compared to the control and tranylcypromine-treated cells. In addition, pargyline induced an increase in the cell death rate by promoting apoptosis; however, tranylcypromine had no effect on LNCaP-LN3 cells. Based on our results, we suggest that pargyline is more powerful than tranylcypromine for the treatment of human prostate cancer.

Proteomic changes induced by histone demethylase JMJD3 in TNF alpha-treated human monocytic (THP-1) cells

JMJD3, a Jumonji C family histone demethylase, plays an important role in the regulation of inflammation induced by the transcription factor nuclear factor-kappa B (NF-κB) in response to various stimuli. JMJD3 is a histone-3 lysine-27 trimethylation (H3K27me3) demethylase, a histone mark associated with transcriptional repression and activation of a diverse set of genes. The present study assessed stable JMJD3 knockdown (KD)-dependent proteomic profiling in human leukemia monocyte (THP-1) cells to analyze the JMJD3-mediated differential changes of marker expression in inflammatory cells. To analyze the protein expression profile of tumor necrosis factor-alpha (TNF-α)-stimulated JMJD3-kd THP-1 cells, we employed matrix-assisted-laser-desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Additionally, Ingenuity Pathways Analysis (IPA) was applied to establish the molecular networks. A comparative proteomic profile was determined in TNF-α-treated both of JMJD3-kd THP-1 cells and THP-1 scrambled (sc) cells. The expression of tripartite motif protein (TRIM5), glutathione peroxidase (GPx), glia maturation factor-γ (GMFG), caspase recruitment domain family, member 14 (CARMA2), and dUTP pyrophosphatase were significantly down-regulated, whereas heat shock protein beta-1 (HspB1) and prohibition were significantly up-regulated in JMJD3-kd THP-1 cells. The molecular and signaling networks of the differentially expressed proteins in JMJD3-kd THP-1 cells were determined by IPA. The molecular network signatures and functional proteomics obtained in this study may facilitate the suppression of different key inflammatory regulators through JMJD3-attenuation, which would be crucial to evaluate potential therapeutic targets and to elucidate the molecular mechanism of JMJD3-kd dependent effects in THP-1 cells.

Effects of the activated mitogen-activated protein kinase pathway via the c-ros receptor tyrosine kinase on the T47D breast cancer cell line following alcohol exposure

Compared to other cancers affecting women, breast cancer is significantly associated with alcohol consumption. However, the principles underlying the carcinogenesis of alcohol-induced breast cancer and the related metastatic mechanisms have yet to be established. To observe the effect of alcohol on the growth regulation in breast cancer cells, we identified differentially expressed proteins in alcohol-exposed human breast cancer T47D cells using gel-based proteomics analysis. The expression of c-ros receptor tyrosine kinase (ROS1) was increased and activated by autophosphorylation, thereby activating mitogen- and stress-activated protein kinase 1 (MSK1) through the mitogen-activated protein kinase (MAPK) pathway; activated MSK1, in turn, phosphorylated histone 3 serine 10 (H3S10p) residues in the nucleus. The increase in H3S10 phosphorylation consequently increased the level of expression of immediate-early gene such as c-fos. This study demonstrated that when breast cancer cells are exposed to alcohol, phosphorylated ROS1 activates MSK1 via ERK1/2 in the MAPK pathway, which then induces modifications to histone residues that regulate gene expression by 14-3-3 protein recruitment, leading to a lack of control of breast cancer cell proliferation.

Functional analysis of histone demethylase Jmjd2b on lipopolysaccharide-treated murine neural stem cells (NSCs)

Neural stem cell (NSC) neurogenesis is the formation of new neurons by which the brain maintains its lifelong plasticity in response to extrinsic and intrinsic changes. Here, we show the effect of lipopolysaccharides (LPS) as an in vitro model of inflammation on NSCs to determine whether the inflammatory mediators can epigenetically affect NSCs and alter their proliferation and differentiation abilities. To study the effect of LPS on NSCs, we used an immortalized mouse neuroectodermal stem cell line, NE-4C. We found that Jmjd2b, histone-3 lysine-9 di-/tri-methyl (H3K9me2/3) demethylase, is functional following LPS treatment and is crucial in multiple signaling pathways and biological processes. The global gene expression levels were detected in Jmjd2b-knockdown (kd) NE-4C cells and in LPS-stimulated Jmjd2b-kd NE-4C cells using an Affymetrix GeneChip(®) Mouse Gene 1.0 ST Array. In addition, the datasets were analyzed using MetaCore Pathway Analysis (GeneGo). The attenuation of Jmjd2b in NE-4C cells significantly affected the p65, iNOS, Bcl2, and TGF-β expression levels and had downstream effects on related signaling pathways. In addition, chromatin immunoprecipitation revealed that Jmjd2b-kd could inhibit the Notch1, IL-1β, and IL-2 genes by recruiting repressive H3K9me3 to their promoters. Moreover, this study highlights Jmjd2b role in LPS-mediated inflammation, which suggests an epigenetic regulation in NE-4C cells. Finally, this study establishes novel Jmjd2b targets that potentiate a biological rationale involving Jmjd2b in NSC inflammation.

Gene networking and inflammatory pathway analysis in a JMJD3 knockdown human monocytic cell line

JMJD3, a Jumonji C family histone demethylase, is induced by transcription factor, nuclear factor-kappa B (NF-κB), in response to various stimuli. JMJD3 is crucial for erasing histone-3 lysine-27 trimethylation (H3K27me3), a modification associated with transcriptional repression and is responsible for the activation of a diverse set of genes. Here, we identify the genes in human leukaemia monocyte (THP-1) human monocytic cells that are significantly affected by the stable knockdown (kd) of JMJD3. Global gene expression levels were detected in stable JMJD3 knockdown THP-1 cells and in tumor necrosis factor-alpha (TNF-α)-stimulated JMJD3-kd THP-1 cells by using a 12-plex NimbleGen human whole genome array. In addition, datasets were analysed by using Ingenuity Pathway Analysis. Stable knockdown of JMJD3 in THP-1 cells affected particularly in expression levels and in downstream effects on inflammatory signalling pathways. JMJD3 attenuation down-regulates various key genes in NF-κB, chemokine and CD40 signalling, and mostly affects inflammatory disease response molecules. In addition, chromatin immunoprecipitation revealed that JMJD3-kd could inhibit several NF-κB-regulated inflammatory genes by recruiting repressive histone-3 lysine-27 trimethylation to their promoters. Moreover, this study significantly highlights the connexion of NF-κB with JMJD3, which suggests an epigenetic regulation in different signalling pathways. Finally, this study establishes novel JMJD3 targets through Ingenuity Pathway Analysis.

Terminalia chebula extract acts as a potential NF-κB inhibitor in human lymphoblastic T cells

Terminalia chebula (TC) is native to southern Asia to southwestern China and is used in traditional medicine for the treatment of human ailments including malignant tumors and diabetes. This plant also has antibacterial and immunomodulatory properties. Nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB) is responsible for the expression of numerous genes involved in cell survival, proliferation, angiogenesis, inflammation, invasion and metastasis, among other processes. This study aims to assess the NF-κB inhibitory effect of TC extract in human lymphoblastic T (Jurkat) cells. The effects of TC extract were investigated using the FRET-based Gene Blazer technique in transfected Jurkat-NF-κB-RE-bla cells. The concentration of TC extract required for NF-κB inhibition was determined by a cell proliferation assay. Treatment with TC extract (50 μg/mL) inhibited NF-κB activity and protected against IκBα degradation and strongly suppressed IκBα phosphorylation in Jurkat-NF-κB-RE-bla cells. This treatment might be crucial for inhibiting NF-κB translocation and activation. In addition, the TC extract downregulated certain NF-κB regulated genes, including IL-8 and MCP-1, in Jurkat-NF-κB-RE-bla cells. Moreover, gallic acid was identified from the TC extract demonstrating its ability to inhibit NF-κB activity in Jurkat-NF-κB-RE-bla cells. Further studies to identify the role of gallic acid in NF-κB inhibition may uncover the crucial antiinflammatory and antitumor properties of the TC extract.

Fluoxetine Up-Regulates Bcl-xL Expression in Rat C6 Glioma Cells

OBJECTIVE

To analyze both differentially expressed genes and the Bcl-xL protein expression after acute and chronic treatment with fluoxetine in rat C6 glioma cells.

METHODS

C6 glioma cells were cultured for 24 h or 72 h after treatment with 10 µM fluoxetine, and gene expression patterns were observed using microarray and qRT-PCR. Then, cells were cultured for 6 h, 24 h, 72 h or 96 h after treatment with 10 µM fluoxetine, and the expression of Bcl-xL protein was measured using western blot.

RESULTS

As determined by microarray, treatment with fluoxetine for 24 h up-regulated 33 genes (including Bcl-xL and NCAM140) and down-regulated 7 genes (including cyclin G-associated kinase). Treatment with fluoxetine for 72 h up-regulated 53 genes (including Gsα and Bcl-xL) and down-regulated 77 genes (including Gαi2 and annexin V). Based on the qRT-PCR results, there was an increase in Gsα mRNA and a decrease in Gαi2 mRNA at 72 h in fluoxetine-treated cells as compared to control, a result that was consistent with microarray. We also observed an increase in Bcl-xL mRNA (both at 24 h and at 72 h) in fluoxetine-treated cells as compared to control, demonstrating a tendency to increase gradually. Bcl-xL protein expression increased as the duration of fluoxetine treatment increased.

CONCLUSION

These results suggest that chronic treatment with fluoxetine not only initiates the cAMP pathway through inducing Gsα expression but also induces Bcl-xL expression, thus inhibiting apoptosis.

Gender differences in antidepressant drug response

Epidemiological studies suggest there are considerable differences in the prevalence and presentation of depression in men and women. Women are more than twice as likely to be diagnosed with depression and may also report more atypical and anxiety symptoms than men. Men and women also differ in the metabolism and distribution of antidepressants and the presence of oestrogen in women of childbearing age may interfere with the mechanism of action of a number of antidepressants. These differences have led many researchers to question whether antidepressants are equally effective and tolerated in men and women. While some reports suggest that selective serotonin re-uptake inhibitors (SSRIs) are more effective and result in fewer adverse drug reactions in women than tricyclic antidepressants (TCAs), gender differences in antidepressant response remains a controversial topic. The potential effects of antidepressant exposure in utero and in breast milk further complicate treatment options for antenatal and postnatal depression. While some research suggests the SSRI paroxetine is teratogenic, further carefully designed naturalistic studies are required to fully evaluate these effects. Finally, response to antidepressants and the occurrence of adverse drug reactions is marked by inter-individual variability which may be in part due to genetic differences. Future studies should therefore consider genotypes of the mother, foetus and infant in antidepressant response.

Ethanol-induced small heat shock protein genes in the differentiation of mouse embryonic neural stem cells

Neural stem cells (NSCs) of the neuroepithelium differentiate into one of three central nervous system (CNS) cell lineages: neurons, astrocytes, or oligodendrocytes. In this study, the differentiation potential of NSCs from the forebrain of embryonic day 15 (E15) mouse embryos was analyzed using immunocytochemistry. NSCs were differentiated early in the presence or absence of ethanol (50 mM), and gene expression patterns among NSCs, differentiated cells and ethanol-treated differentiated cells were assessed by microarray and real-time PCR analysis. Genes that were up-regulated in differentiated cells both in the presence and in the absence of ethanol when compared to NSCs were related to the Wnt signaling pathway, including Ctnna1, Wnt5a, Wnt5b, Wnt7a, Fzd3, and Fzd2; genes related to cell adhesion, including Cadm1, Ncam1, and Ncam2; and genes encoding small heat shock proteins, including HspB2, HspB7, and HspB8. In particular, the expression levels of HspB2 and HspB7 were elevated in ethanol-treated differentiated cells compared to non-treated differentiated cells. The gene expression patterns of various heat shock transcription factors (HSFs), proteins that regulate the transcription of heat shock genes, were also analyzed. The expression levels of HSF2 and HSF5 increased in differentiated cells in the presence and absence of ethanol when compared to NSCs. Of these two genes, HSF5 demonstrated an enhanced up-regulation, particularly in ethanol-treated differentiated cells compared to cells that were differentiated in the absence of ethanol. These results imply that HspB2 and HspB7, which are small heat shock proteins with tissue-restricted expression profiles, might be up-regulated by ethanol during the short-term differentiation of NSCs.

Assessing the neuronal serotonergic target-based antidepressant stratagem: impact of in vivo interaction studies and knockout models

Depression remains a challenge in the field of affective neuroscience, despite a steady research progress. Six out of nine basic antidepressant mechanisms rely on serotonin neurotransmitter system. Preclinical studies have demonstrated the significance of serotonin receptors (5-HT_1-3,6,7), its signal transduction pathways and classical down stream targets (including neurotrophins, neurokinins, other peptides and their receptors) in antidepressant drug action. Serotonergic control of depression embraces the recent molecular requirements such as influence on proliferation, neurogenesis, plasticity, synaptic (re)modeling and transmission in the central nervous system. The present progress report analyses the credibility of each protein as therapeutically relevant target of depression. In vivo interaction studies and knockout models which identified these targets are foreseen to unearth new ligands and help them transform to drug candidates. The importance of the antidepressant assay selection at the preclinical level using salient animal models/assay systems is discussed. Such test batteries would definitely provide antidepressants with faster onset, efficacy in resistant (and co-morbid) types and with least adverse effects. Apart from the selective ligands, only those molecules which bring an overall harmony, by virtue of their affinities to various receptor subtypes, could qualify as effective antidepressants. Synchronised modulation of various serotonergic sub-pathways is the basis for a unique and balanced antidepressant profile, as that of fluoxetine (most exploited antidepressant) and such a profile may be considered as a template for the upcoming antidepressants. In conclusion, 5-HT based multi-targeted antidepressant drug discovery supported by in vivo interaction studies and knockout models is advocated as a strategy to provide classic molecules for clinical trials.

Inhibitory effect of glycoprotein isolated from Opuntia ficus-indica var. saboten MAKINO on activities of allergy-mediators in compound 48/80-stimulated mast cells

The present study was performed to investigate the anti-allergy potentials of glycoprotein (90kDa) isolated from Opuntia ficus-indica var. saboten MAKINO (OFI glycoprotein) in vivo (ICR mice) and in vitro (RBL-2H3 cells). At first, to know whether the OFI glycoprotein has an inhibitory ability for allergy in vivo, we evaluated the activities of allergy-related factors such as histamine and beta-hexosaminidase release, lactate dehydrogenase (LDH), and interleukin 4 (IL-4) in compound 48/80 (8 ml/kg BW)-treated ICR mice. After that, we studied to found the effect for anti-allergy in vitro such as nuclear factor kappa B (NF-kappaB) and inducible nitric oxide synthase (iNOS), extracellular signal-regulated kinase (ERK) 1/2, arachidonic acid, and cyclooxygenase-2 (COX-2) in compound 48/80 (5 microg/ml)-treated RBL-2H3 cells. Our results showed that the OFI glycoprotein (5 mg/kg) inhibited histamine and beta-hexosaminidase release, lactate dehydrogenase (LDH), and interleukin 4 (IL-4) in mice serum. Also OFI glycoprotein (25 microg/ml) has suppressive effects on the expression of MAPK (ERK1/2), and on protein expression of anti-allergic proteins (iNOS and COX-2). Thus, we speculate that the OFI glycoprotein is an example of natural compound that blocks anti-allergic signal transduction pathways.

The role of NF-kappaB and H3K27me3 demethylase, Jmjd3, on the anthrax lethal toxin tolerance of RAW 264.7 cells

BACKGROUND

In Bacillus anthracis, lethal toxin (LeTx) is a critical virulence factor that causes immune suppression and toxic shock in the infected host. NF-kappaB is a key mediator of the inflammatory response and is crucial for the plasticity of first level immune cells such as macrophages, monocytes and neutrophils. In macrophages, this inflammatory response, mediated by NF-kappaB, can regulate host defense against invading pathogens. A Jumonji C family histone 3 lysine-27 (H3K27) demethylase, Jmjd3, plays a crucial role in macrophage plasticity and inflammation. Here we report that NF-kappaB and Jmjd3 can modulate the LeTx intoxication resistance of RAW 264.7 cells.

PRINCIPAL FINDINGS

This study showed that a 2 h exposure of macrophages to LeTx caused substantial cell death with a survival rate of around 40%. The expression of the Jmjd3 gene was induced 8-fold in intoxication-resistant cells generated by treatment with lipopolysaccharides of RAW 264.7 cells. These intoxication-resistant cell lines (PLx intox and PLxL intox) were maintained for 8 passages and had a survival rate of around 100% on secondary exposure to LeTx and lipopolysaccharides. Analysis of NF-kappaB gene expression showed that the expression of p100, p50 and p65 was induced around 20, 7 and 4 fold, respectively, in both of the intoxication-resistant cell lines following a 2 h treatment with PLxL (0.1+0.1+1 microg/ml). In contrast, these NF-kappaB genes were not induced following treatment with PLx treatment at the same concentrations.

CONCLUSIONS

Although LeTx influences macrophage physiology and causes defects of some key signaling pathways such as GSK3beta which contributes to cytotoxicity, these results indicate that modulation of NF-kappaB by p50, p100 and Jmjd3 could be vital for the recovery of murine macrophages from exposure to the anthrax lethal toxin.

Artificial microRNA-based neurokinin-1 receptor gene silencing reduces alcohol consumption in mice

In the brain, the stress system plays an important role in motivating continued alcohol use and relapse. The neuropeptide substance P and the neurokinin-1 receptor (NK1R) are involved in the stress response and drug reward systems. Recent findings have shown that the binding of ligands to NK1Rs decreases the self-administration of alcohol in mice. We examined the effect of an artificial microRNA (amiRNA) on the functional expression of NK1R in mouse brains. Lentiviruses expressing either an amiRNA targeting the NK1R (amiNK1R) or a negative control amiRNA (amiNC) were injected into mouse brains. Four weeks after amiRNA injection, we found that amiNK1R decreased the voluntary alcohol consumption compared to mice injected with amiNC. We also observed that NK1R expression was reduced in the hippocampus. RNA interference is an effective approach to regulate the expression of specific behavior-related genes. Our results support the potential use of amiRNA as a therapeutic agent for the treatment of alcohol dependence.

Increases in serotonergic neuronal activity following intracerebroventricular administration of AF64A in rats

Changes in the serotonergic nervous system after the intracerebroventricular (i.c.v.) administration of ethylcholine aziridinium (AF64A, 3 nmol/each ventricle) were studied in rats. Two weeks after the infusion of AF64A, the levels of 5-HT and 5-HIAA in microdialysed cerebrospinal fluid (CSF), the levels of total 5-HT and 5-HIAA, the density of serotonin uptake sites and the activities of tryptophan hydroxylase (TPH) and monoamine oxidase (MAO) in various brain regions were determined. After AF64A administration, the concentrations of 5-HT in lateral ventricle were increased and the levels of 5-HIAA were decreased. However, the hippocampal levels of total 5-HT were decreased without changes in the levels of 5-HIAA and the hippocampal turnover rates of 5-HT increased. Also, the density of uptake sites of serotonin ([(3)H]citalopram binding sites) was decreased in the various brain. The activities of TPH were increased in striatum and frontal cortex and the activity of MAO was also increased in striatum. These results indicate that AF64A induces an increase in serotonergic neuronal activity and decreased densities of 5-HT uptake sites which may affect the change in the other parameters of serotonergic neuronal activities. Furthermore, these results suggest that the impaired cholinergic neuronal activity induces the alteration in the serotonergic nervous activities.

Apoptosis-related genes change their expression with age and hearing loss in the mouse cochlea

To understand possible causative roles of apoptosis gene regulation in age-related hearing loss (presbycusis), apoptotic gene expression patterns in the CBA mouse cochlea of four different age and hearing loss groups were compared, using GeneChip and real-time (qPCR) microarrays. GeneChip transcriptional expression patterns of 318 apoptosis-related genes were analyzed. Thirty eight probes (35 genes) showed significant differences in expression. The significant gene families include Caspases, B-cell leukemia/lymphoma2 family, P53, Calpains, Mitogen activated protein kinase family, Jun oncogene, Nuclear factor of kappa light chain gene enhancer in B-cells inhibitor-related and tumor necrosis factor-related genes. The GeneChip results of 31 genes were validated using the new TaqMan Low Density Array (TLDA). Eight genes showed highly correlated results with the GeneChip data. These genes are: activating transcription factor3, B-cell leukemia/lymphoma2, Bcl2-like1, caspase4 apoptosis-related cysteine protease 4, Calpain2, dual specificity phosphatase9, tumor necrosis factor receptor superfamily member12a, and Tumor necrosis factor superfamily member13b, suggesting they may play critical roles in inner ear aging.

Serotonin 2B receptor: Upregulated with age and hearing loss in mouse auditory system

Serotonin (5-HT) is a monoamine neurotransmitter. Serotonin may modulate afferent fiber discharges in the cochlea, inferior colliculus (IC) and auditory cortex. Specific functions of serotonin are exerted upon its interaction with specific receptors; one of those receptors is the serotonin 2B receptor. The aim of this study was to investigate the differences in gene expression of serotonin 2B receptors with age in cochlea and IC, and the possible correlation between gene expression and functional hearing measurements in CBA/CaJ mice. Immunohistochemical examinations of protein expression of IC in mice of different age groups were also performed. Gene expression results showed that serotonin 2B receptor gene was upregulated with age in both cochlea and IC. A significant correlation between gene expression and functional hearing results was established. Immunohistochemical protein expression studies of IC showed more serotonin 2B receptor cells in old mice relative to young adult mice, particularly in the external nucleus. We conclude that serotonin 2B receptors may play a role in the pathogenesis of age-related hearing loss.

FLUOXETINE modifies the expression of serotonergic markers in a differentiation-dependent fashion in the mesencephalic neural cell line A1 mes c-myc

Serotonin (5-HT) is a neurotransmitter involved in a variety of CNS functions during development and in adulthood. 5-HT neurons are also involved in the pathogenesis of a number of psychiatric disorders. FLUOXETINE (FLX), a prototypic antidepressant, is a selective 5-HT uptake inhibitor (SSRI) with a demonstrated clinical efficacy in these disorders. SSRI, in a short-term period, binds 5-HT transporter (SERT) raising 5-HT levels at the synapse. Nevertheless, clinical improvement is observed only after 3-4 weeks of treatment. Recently, it has been shown that antidepressants, besides interfering with neurotransmission, can also display an effect on neural cells' proliferation and differentiation. Therefore it has been proposed that antidepressant may exert their clinical effects also acting on cellular functions other then neurotransmission. Here we show that a mesencephalic neural cell line, mes-c-myc A1 (A1) produces 5-HT and expresses SERT and both peripheral (TPH1) and CNS-specific (TPH2) form of tryptophan hydroxylase, the limiting enzyme in 5-HT biosynthesis. Cyclic AMP-dependent neuronal differentiation of A1 cells modulates the expression of TPHs. FLX, as well as citalopram (CIT), another SSRI inhibitor, modulates expression of serotonergic markers depending on the differentiation status of the cells. Interestingly, long-term but not short-term FLX treatment selectively modulates mRNA levels of TPH2, only in differentiated A1 cells. Finally, FLX and citalopram selectively decrease the proliferation rate of undifferentiated A1 cells, whereas have no effects on NIH-3T3 fibroblasts proliferation. In conclusion, neuronal differentiation of A1 cells not only modulates the expression of serotonergic markers, but appears to affect the response to FLX.

Proteomic analysis of rat cortical neurons after fluoxetine treatment

The known neurochemical effect of most currently available antidepressants is the enhancement of the synaptic levels of monoamine neurotransmitters. However, the existence of other mechanisms has been suggested to justify the significant delay between the modulation of the monoaminergic system and the clinical effects. In order to investigate the effects of the antidepressant fluoxetine (a prototypical serotonin selective re-uptake inhibitor) and to improve the understanding of its mechanism of action, we performed a proteomic investigation in rat primary cortical neurons exposed sub-chronically to this antidepressant. Cortical neurons were treated for 3 days with 1 microM fluoxetine or vehicle. Protein extracts were processed for 2D gel characterization. Image analysis allowed the identification of six proteins differently expressed by more than 100% and seven proteins differently expressed by more than 50% (P<0.05). Nine proteins were identified by mass spectrometry. Among them, cyclophilin A, 14-3-3 protein z/delta and GRP78 are involved in neuroprotection, in serotonin biosynthesis and in axonal transport, respectively. This study showed that the primary culture of cortical neurons is a suitable system for studying the effects of fluoxetine action and may contribute to improve the understanding of fluoxetine psychotherapeutic action and the mechanisms mediating the long-term effects of this antidepressant treatment.

Glutamate-related gene expression changes with age in the mouse auditory midbrain

Glutamate is the main excitatory neurotransmitter in both the peripheral and central auditory systems. Changes of glutamate and glutamate-related genes with age may be an important factor in the pathogenesis of age-related hearing loss-presbycusis. In this study, changes in glutamate-related mRNA gene expression in the CBA mouse inferior colliculus with age and hearing loss were examined and correlations were sought between these changes and functional hearing measures, such as the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAEs). Gene expression of 68 glutamate-related genes was investigated using both genechip microarray and real-time PCR (qPCR) molecular techniques for four different age/hearing loss CBA mouse subject groups. Two genes showed consistent differences between groups for both the genechip and qPCR. Pyrroline-5-carboxylate synthetase enzyme (Pycs) showed down-regulation with age and a high-affinity glutamate transporter (Slc1a3) showed up-regulation with age and hearing loss. Since Pycs plays a role in converting glutamate to proline, its deficiency in old age may lead to both glutamate increases and proline deficiencies in the auditory midbrain, playing a role in the subsequent inducement of glutamate toxicity and loss of proline neuroprotective effects. The up-regulation of Slc1a3 gene expression may reflect a cellular compensatory mechanism to protect against age-related glutamate or calcium excitoxicity.