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Inhibition of basal, staurosporine- or hydrogen peroxide-induced cell death of NPCs by VPA. NPCs culture were treated with 0.2 mM or 0.5 mM VPA or PBS (Vehicle) and stimulated with 100 nM staurosporine or 100 μM H2O2. Cells were analyzed by FACS analysis or PI staining 8 hr after the treatment as described in materials and methods. (A) The ratios of apoptotic cells were measured by FACS analysis after PI staining. (B) Quantification of FACS data (n = 3). (C) PI cytochemical staining. VPA decreased the number of PI positive cells. (D) Quantification of PI staining data (n = 6), Results are mean ± S.E.M. **P < 0.01 and ***P < 0.001 vs. Vehicle. ## p < 0.01, ### p < 0.001 vs. control. Scale bar represents 100 μm.
Source publication
At the beginning of neurogenesis, massive brain cell death occurs and more than 50% of cells are eliminated by apoptosis along with neuronal differentiation. However, few studies were conducted so far regarding the regulation of neural progenitor cells (NPCs) death during development. Because of the physiological role of cell death during developme...
Contexts in source publication
Context 1
... FACS analysis, the ratio of PI positive dead cell was increased by staurosporine or H 2 O 2 treatment. 0.2 and 0.5 mM of VPA decreased cell death in basal condition as well as staurosporine-or H 2 O 2 -stimulated conditions ( Figure 1A, B). To visualize the protective effect of VPA, we stained NPCs with PI solution, which gave similar results as FACS analysis ( Figure 1C, D). ...Context 2
... and 0.5 mM of VPA decreased cell death in basal condition as well as staurosporine-or H 2 O 2 -stimulated conditions ( Figure 1A, B). To visualize the protective effect of VPA, we stained NPCs with PI solution, which gave similar results as FACS analysis ( Figure 1C, D). In this condition, staurosporine and H 2 O 2 didn't change either NF-B expression or translocation to nucleus (data not shown). ...Citations
... Cellular pre-incubation with VPA and TSA sustained the pro-inflammatory medium. Correspondingly, VPA elevated IL-6 and IL-1β expression levels in neural progenitor cells [31,32]. In contrast, it lowered TNF-α and IL-6 production in murine bone marrow-derived macrophages stimulated with Pam3CSK4 [33]. ...
Objectives
This in vitro study aimed to modify TLR-2-mediated effects on the paracrine, proliferative, and differentiation potentials of human dental pulp–derived cells using histone acetyltransferase (HAT) and histone deacetylase (HDAC) inhibitors.
Materials and methods
Cell viability was assessed using the XTT assay. Cells were either treated with 10 μg/ml Pam3CSK4 only, or pre-treated with valproic acid (VPA) (3 mM), trichostatin A (TSA) (3 μM), and MG-149 (3 μM) for a total of 4 h and 24 h. Control groups included unstimulated cells and cells incubated with inhibitors solvents only. Transcript levels for NANOG, OCT3-4, FGF-1 and 2, NGF, VEGF, COL-1A1, TLR-2, hβD-2 and 3, BMP-2, DSPP, and ALP were assessed through qPCR.
Results
After 24 h, TSA pre-treatment significantly upregulated the defensins and maintained the elevated pro-inflammatory cytokines, but significantly reduced healing and differentiation genes. VPA significantly upregulated the pro-inflammatory cytokine levels, while MG-149 significantly downregulated them. Pluripotency genes were not significantly affected by any regimen.
Conclusions
At the attempted concentrations, TSA upregulated the defensins gene expression levels, and MG-149 exerted a remarkable anti-inflammatory effect; therefore, they could favorably impact the immunological profile of hDPCs.
Clinical relevance
Targeting hDPC nuclear function could be a promising option in the scope of the biological management of inflammatory pulp diseases.
... Furthermore, in an experiment in which valproic acid was administered to pregnant rats, it was found to prevent apoptosis by increasing Bcl2 expression and decreasing the expression of developing neurons. This mechanism, in fact, explains the harmful consequences of VPA (teratogenicity) during fetal exposure (Go et al., 2011). ...
Valproic acid, a branching short chain fatty acid, is a popular drug to treat epilepsy and acts as a mood-stabilizing drug. The obstruction of ion channels and Gamma Amino Butyrate transamino butyrate GABA has been linked to antiepileptic effects. Valproic acid has been characterized as a Histone deacetylase inhibitor, functioning directly transcription of gene levels by blocking the deacetylation of histones and increasing the accessibility of transcription sites. Study has been extensively focused on pharmaceutical activity of valproic acid through various pharmacodynamics activity from absorption, distribution and excretion particularly in patients who are resistant to or intolerant of lithium or carbamazepine, as well as those with mixed mania or rapid cycling.
... Edaravone can protect hippocampal neurons from damage in KA-induced epilepsy rats by upregulating Nrf2 and downregulating NF-κB . Valproic acid can reduce the death of neural progenitor cells through the activation of NF-κB signaling (Go et al., 2011), which indicates that NF-κB can promote neuronal survival mentioned above. Long-term use of Antiseizure medications, such as phenytoin (Zhou et al., 2015), valproic acid (Rao et al., 2007), carbamazepine (Yu et al., 2017), pregabalin (Nader et al., 2018;Attia et al., 2019), and diazepam (Firdous et al., 2021), can reduce the amount of NF-κB in animal tissues or cells to protect neurons and suppress inflammation. ...
The transcriptional regulator nuclear factor kappa B (NF-κB) modulates cellular biological activity by binding to promoter regions in the nucleus and transcribing various protein-coding genes. The NF-κB pathway plays a major role in the expressing genes related to inflammation, including chemokines, interleukins, and tumor necrosis factor. It also transcribes genes that can promote neuronal survival or apoptosis. Epilepsy is one of the most common brain disorders and it not only causes death worldwide but also affects the day-to-day life of affected individuals. While epilepsy has diverse treatment options, there remain patients who are not sensitive to the existing treatment methods. Recent studies have implicated the critical role of NF-κB in epilepsy. It is upregulated in neurons, glial cells, and endothelial cells, due to neuronal loss, glial cell proliferation, blood-brain barrier dysfunction, and hippocampal sclerosis through the glutamate and γ-aminobutyric acid imbalance, ion concentration changes, and other mechanisms. In this review, we summarize the functional changes caused by the upregulation of NF-κB in the central nervous system during different periods after seizures. This review is the first to deconvolute the complicated functions of NF-κB, and speculate that the regulation of NF-κB can be a safe and effective treatment strategy for epilepsy.
... VPA treatment alters Bcl2 expression and inhibits caspase-3 activation, which may be a protective mechanism of VPA against apoptosis in injured neurons [64]. Moreover, VPA was also reported to reduce apoptosis through up regulation of Bcl2 and down regulation of Bax expression in developing neurons in a study in which VPA was given to pregnant rats [65]. This effect is indeed explaining the toxic effects of VPA (teratogenicity) after fetal exposure. ...
Valproic acid (VPA) is an approved drug for managing epileptic seizures, bipolar disorders, and migraine. VPA has been shown to elevate the level of gamma-aminobutyric acid (GABA) in the brain through competitive inhibition of GABA transaminase, thus promoting the availability of synaptic GABA and facilitating GABA-mediated responses. VPA, which is a small chain of fatty acids, prevents histone deacetylases (HDACs). HDACs play a crucial role in chromatin remodeling and gene expression through posttranslational changes of chromatin-associated histones. Recent studies reported a possible effect of VPA against particular types of cancers. This effect was partially attributed to its role in regulating epigenetic modifications through the inhibition of HDACs, which affect the expression of genes associated with cell cycle control, cellular differentiation, and apoptosis. In this review, we summarize the current information on the actions of VPA in diseases such as diabetes mellitus, kidney disorders, neurodegenerative diseases, muscular dystrophy, and cardiovascular disorders.
... VPA treatment enhanced apoptotic cell death in the cerebellum and hippocampus of treated mice [23]. On the other hand, there are recent studies that report attenuation of apoptosis [24] or reduction of the rate of neuronal apoptosis with VPA [25] and reduced death of neural progenitor cells by VPA at developmentally critical periods [26]. The fact is that the exact action mechanisms of VPA-induced teratogenicity are still unclear [19,27]. ...
Objectives: The purpose of this study was to examine the teratogenic effects of Valproic Acid (VPA) and to investigate the role of apoptosis in neural tissue development. Although an apoptotic activity due to VPA has been reported, a direct connection of VPA-induced apoptosis with embryonic brain and/or spine malformations and teratogenesis has not yet been established. Materials and Methods: VPA was administered to BALB/c mice, from the 7 th to the 10 th gestational days. Macroscopical congenital anomalies were registered under a stereomicroscope and were further histologically studied. Immunohistochemistry was performed with terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) staining. Results: Birth defects were described and an increase of the apoptotic activity in the brain was immunohistochemically identified. Conclusions: Considering the increased and very intense TUNEL expression of the neural cells of treated animals' fetuses, it is suggested that VPA triggers a pathological increase of apoptosis resulting in an imbalance between cell proliferation and cell death, the final result of which is malformation.
... Recently studies showed that valproic acid has acted as a histone deacetylase (HDAC) inhibitor and a nuclear and mitochondrial DNA methylation agent as it directly deteriorates gene transcription levels in the brain (Wolters et al. 2017). This medication inhibits cell proliferation and causes neuronal damage and apoptosis in neuronal progenitor cell (Go et al. 2011). Apart from neurotoxic insults, many studies have indicated that antioxidants play a neuroprotective role against the neurotoxicity induced by valproic acid (Salim 2017). ...
... VPA treatment enhanced apoptotic cell death in the cerebellum and hippocampus of treated mice [23]. On the other hand, there are recent studies that report attenuation of apoptosis [24] or reduction of the rate of neuronal apoptosis with VPA [25] and reduced death of neural progenitor cells by VPA at developmentally critical periods [26]. The fact is that the exact action mechanisms of VPA-induced teratogenicity are still unclear [19,27]. ...
Objectives:
The purpose of this study was to examine the teratogenic effects of Valproic Acid (VPA) and to investigate the role of apoptosis in neural tissue development. Although an apoptotic activity due to VPA has been reported, a direct connection of VPA-induced apoptosis with embryonic brain and∕or spine malformations and teratogenesis has not yet been established.
Materials and methods:
VPA was administered to BALB∕c mice, from the 7th to the 10th gestational days. Macroscopical congenital anomalies were registered under a stereomicroscope and were further histologically studied. Immunohistochemistry was performed with terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) staining.
Results:
Birth defects were described and an increase of the apoptotic activity in the brain was immunohistochemically identified.
Conclusions:
Considering the increased and very intense TUNEL expression of the neural cells of treated animals' fetuses, it is suggested that VPA triggers a pathological increase of apoptosis resulting in an imbalance between cell proliferation and cell death, the final result of which is malformation.
... We do not discount the possibility that VPA may modulate other aspects of NF-B properties. For instance, VPA has been documented to influence NF-B properties that span regulation of expression to post-translational nuclear translocation [42][43][44][45][46][47][48][49]. Nonetheless, on the level of protein expression, VPA effects on the NF-B family are highly specific. ...
Valproic acid (VPA) is a histone deacetylase inhibitor used clinically for neurological disorders. It is also potentially useful as anti-fibrotic therapy as it reduced collagen deposition in the post-operative conjunctiva. In this study, we further evaluated the effects of VPA on post-operative inflammation using the mouse model of conjunctival scarring. VPA, injected into the subconjunctiva immediately after surgery, did not cause any adverse tissue response when examined by live microscopy and produced an apparent reduction of proinflammatory and proangiogenic markers in immunohistological examinations. In-depth analyses of the treated operated tissues revealed that VPA selectively inhibited the CD45highF4/80low macrophage subset as well as the production of specific proinflammatory cytokines/ chemokines, including CXCL1, IL-5, IL-6, and IL-10 which were reduced by ≥ 2.0-fold. VPA also specifically reduced tissue NF-кB2 p100 protein by mean 3.87-fold. On conjunctival fibroblasts, VPA treatment resulted in decreased secretion of specific cytokines, including CCL2, VEGF-A, and IL-15. In the presence of TNF-α, VPA inhibited the induction of specific cytokines/chemokines, notably CCL5 and VEGF-A, as well as NF-кB2 p100. In corroboration, VPA suppressed TNF-α stimulation of NF-кB reporter transcription by 1.51-fold. These data indicate that VPA can modulate both proinflammatory cellular and molecular targets in a selective manner and may therefore attenuate surgery-induced conjunctival inflammation. These and previous findings suggest that, by suppressing key mediators of both inflammation and fibrosis, VPA is a useful therapeutic for improving surgical outcome involving the conjunctiva.
Key messages
• VPA inhibited recruitment of a CD45highF4/80low macrophage subset.
• VPA reduced chemokine and cytokine levels in treated tissues.
• VPA selectively suppressed tissue NF-кB2 p100 levels.
• VPA suppressed TNF-α induction of chemokines, cytokines and NF-кB2 p100 expression.
• VPA suppressed TNF-α stimulation of NF-кB reporter.
... Various studies have demonstrated that NF-κB may inhibit the apoptosis of various types of cancer cells as NF-κB serves as a nuclear factor that regulates the expression of various cell apoptosis-inhibiting genes at the transcriptional level, including XIAP, cIAP1and B-cell lymphoma-extra-large (27)(28)(29). XIAP and cIAP1 belong to the family of inhibitor of apoptosis (IAP) proteins, which constitute a highly conserved family of endogenous anti-apoptotic factors that suppress apoptosis by inhibiting caspase activity (30). IAP family proteins within the mitochondrial pathway are able to bind to caspase-9 precursors and interfere with their processing. ...
Thyroid carcinoma is primarily treated by surgery combined with radioactive 131iodine (131I) treatment; however, certain patients exhibit resistance to 131I treatment. Previous research indicated that nuclear factor‑κB (NF‑κB) was associated with resistance to 131I in cancer cells. The present study aimed to investigate the effects of NF‑κB on 131I uptake and apoptosis in thyroid carcinoma cells. TPC‑1 and BCPAP cell lines were employed as research models in the present study, and the expression of NF‑κB was inhibited by RNA interference (RNAi). The ability of TPC‑1 and BCPAP cells to uptake 131I was measured and the cell viability was detected by an MTT assay. Finally, the expression of the apoptosis‑associated proteins X‑linked inhibitor of apoptosis (XIAP), cellular inhibitor of apoptosis protein 1 (cIAP1) and caspase‑3 in TCP‑1 and BCPAP cells was determined by western blotting. Western blotting results demonstrated that the expression levels of NF‑κB in TPC‑1 and BCPAP cells were successfully downregulated by RNAi (P<0.05), while analysis of 131I uptake revealed no significant alterations in the 131I uptake ability of cells following RNAi (P>0.05). MTT experiments demonstrated that the inhibition of NF‑κB expression in combination with radiation (131I treatment) led to a marked reduction in cell viability (P<0.05). Furthermore, western blot analysis revealed that the inhibition of NF‑κB expression downregulated the expression levels of XIAP and cIAP1 (P<0.05), while the expression levels of caspase‑3 were upregulated, indicating that the observed reduction in cell viability following NF‑κB inhibition may be due to an increased level of apoptosis. Although NF‑κB inhibition did not affect the 131I uptake of thyroid cancer cells, this inhibition may increase the apoptotic effects of radioactive 131I.
... This study further expands the relevance of the VPA model of autism as a strong environmental contributor to ASD with a significant clinical relevance [33,34]. We already learned through various validated rodent models that VPA induces altered neuronal apoptosis [35], increased neuronal cell progenitor pool and macrocephaly phenotype [24], increased neurite outgrowth in rat primary cortical neurons [36], altered glutamate regulations in the hippocampus [37], cerebellar anomalies [38], histone hyperacetylation and MeCP2 altered expression [39,40], and imbalance between excitation and inhibition neurotransmission [1,41,42], among others. In the current study, we firstly understood that VPA enhances TERT expression. ...
The valproic acid (VPA)-induced animal model is one of the most widely utilized environmental risk factor models of autism. Autism spectrum disorder (ASD) remains an insurmountable challenge among neurodevelopmental disorders due to its heterogeneity, unresolved pathological pathways and lack of treatment. We previously reported that VPA-exposed rats and cultured rat primary neurons have increased Pax6 expression during post-midterm embryonic development which led to the sequential upregulation of glutamatergic neuronal markers. In this study, we provide experimental evidence that telomerase reverse transcriptase (TERT), a protein component of ribonucleoproteins complex of telomerase, is involved in the abnormal components caused by VPA in addition to Pax6 and its downstream signals. In embryonic rat brains and cultured rat primary neural progenitor cells (NPCs), VPA induced the increased expression of TERT as revealed by Western blot, RT-PCR, and immunostainings. The HDAC inhibitor property of VPA is responsible for the TERT upregulation. Chromatin immunoprecipitation revealed that VPA increased the histone acetylation but blocked the HDAC1 binding to both Pax6 and Tert genes. Interestingly, the VPA-induced TERT overexpression resulted to sequential upregulations of glutamatergic markers such as Ngn2 and NeuroD1, and inter-synaptic markers such as PSD-95, α-CaMKII, vGluT1 and synaptophysin. Transfection of Tert siRNA reversed the effects of VPA in cultured NPCs confirming the direct involvement of TERT in the expression of those markers. This study suggests the involvement of TERT in the VPA-induced autistic phenotypes and has important implications for the role of TERT as a modulator of balanced neuronal development and transmission in the brain.
