Duality of Valproic Acid Effects on Inflammation, Oxidative Stress and Autophagy in Human Eosinophilic Cells

Valproic Acid Causes Redox-Regulated Post-Translational Protein Modifications That Are Dependent upon P19 Cellular Differentiation States

Valproic acid (VPA) is a common anti-epileptic drug and known neurodevelopmental toxicant. Although the exact mechanism of VPA toxicity remains unknown, recent findings show that VPA disrupts redox signaling in undifferentiated cells but has little effect on fully differentiated neurons. Redox imbalances often alter oxidative post-translational protein modifications and could affect embryogenesis if developmentally critical proteins are targeted. We hypothesize that VPA causes redox-sensitive post-translational protein modifications that are dependent upon cellular differentiation states. Undifferentiated P19 cells and P19-derived neurons were treated with VPA alone or pretreated with D3T, an inducer of the nuclear factor erythroid 2-related factor 2 (NRF2) antioxidant pathway, prior to VPA exposure. Undifferentiated cells treated with VPA alone exhibited an oxidized glutathione redox couple and increased overall protein oxidation, whereas differentiated neurons were protected from protein oxidation via increased S-glutathionylation. Pretreatment with D3T prevented the effects of VPA exposure in undifferentiated cells. Taken together, our findings support redox-sensitive post-translational protein alterations in undifferentiated cells as a mechanism of VPA-induced developmental toxicity and propose NRF2 activation as a means to preserve proper neurogenesis.

Preclinical Study in Mouse Thymus and Thymocytes: Effects of Treatment with a Combination of Sodium Dichloroacetate and Sodium Valproate on Infectious Inflammation Pathways

The research presents data from a preclinical study on the anti-inflammatory effects of a sodium dichloroacetate and sodium valproate combination (DCA-VPA). The 2-week treatment with a DCA 100 mg/kg/day and VPA 150 mg/kg/day combination solution in drinking water's effects on the thymus weight, its cortex/medulla ratio, Hassall's corpuscles (HCs) number in the thymus medulla, and the expression of inflammatory and immune-response-related genes in thymocytes of male Balb/c mice were studied. Two groups of mice aged 6-7 weeks were investigated: a control (n = 12) and a DCA-VPA-treated group (n = 12). The treatment did not affect the body weight gain (p > 0.05), the thymus weight (p > 0.05), the cortical/medulla ratio (p > 0.05), or the number of HCs (p > 0.05). Treatment significantly increased the Slc5a8 gene expression by 2.1-fold (p < 0.05). Gene sequence analysis revealed a significant effect on the expression of inflammation-related genes in thymocytes by significantly altering the expression of several genes related to the cytokine activity pathway, the inflammatory response pathway, and the Il17 signaling pathway in thymocytes. Data suggest that DCA-VPA exerts an anti-inflammatory effect by inhibiting the inflammatory mechanisms in the mouse thymocytes.