Function of Thymosin Beta-4 in Ethanol-Induced Microglial Activation.

BACKGROUND/AIMS: Neuroinflammation mediated by activated microglia may play a pivotal role in a variety of central nervous system (CNS) pathologic conditions, including ethanol-induced neurotoxicity. The purpose of this study was to investigate the function of Tβ4 in ethanol-induced microglia activation. METHODS: Quantitative real-time PCR was conducted to assess the expression of Tβ4 and miR-339-5p. Western blot analysis was used to measure the expression of Tβ4, phosphorylated p38, ERK, JNK, Akt, and NF-x03BA;B p65. The concentration of TNF-α and IL-1β was determined using ELISA. NO concentration was measured using a nitric oxide colorimetric BioAssay Kit. Double immunofluorescence was performed to determine Tβ4 expression, in order to assess microglial activation in neonatal mouse FASD model. RESULTS: Increased Tβ4 expression was observed in ethanol treated microglia. Knockdown of Tβ4 enhanced ethanol-induced inflammatory mediators tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) and nitric oxide (NO) in BV-2 cells was performed. Exogenous Tβ4 treatment significantly inhibited expression and secretion of these inflammatory mediators. Tβ4 treatment attenuated p38, ERK MAPKs, and nuclear factor-kappa B (NF-x03BA;B) pathway activation, and enhanced miR-339-5p expression induced by ethanol exposure in microglia. A neonatal mouse fetal alcohol spectrum disorders (FASD) model showed that Tβ4 expression in the microglia of the hippocampus was markedly enhanced, while Tβ4 treatment effectively blocked the ethanol-induced increase in inflammatory mediators, to the level expressed in vehicle-treated control animals. CONCLUSION: This study is the first to demonstrate the function of Tβ4 in ethanol-induced microglia activation, thus contributing to a more robust understanding of the role of Tβ4 treatment in CNS disease.