Transport Alteration of 4-Phenyl Butyric Acid Mediated by a Sodium- and Proton-Coupled Monocarboxylic Acid Transporter System in ALS Model Cell Lines (NSC-34) Under Inflammatory States

4-Phenyl butyric acid (PBA) has histone deacetylase inhibitory and neuroprotective effects. We aimed to examine the transport alteration activity of PBA in control (WT) and disease (MT) model cell lines of an amyotrophic lateral sclerosis (ALS) model. The transport characteristics of PBA were examined uptake rates and mRNA expression levels in NSC-34 cell lines. PBA uptake was pH, sodium, and concentration dependent. The K_m and V_max values for PBA uptake in the MT were more than two-fold higher than those in the WT. The presence of monocarboxylic acids (MA) and inhibitors of MA transporter (MCT) inhibited the uptake of PBA. PBA showed competitive inhibition in the presence of MAs in both cell lines. SiRNA transfection studies showed that PBA can be transported to NSC-34 cell lines through sodium-coupled MCT1. TNF-α and H₂O₂ increased, but LPS and glutamate reduced the uptake rate after the pretreatment of the MT cell lines. SMCT1 mRNA expression levels, in the presence of oxidative stress inducing agents, showed consistent results with the uptake results. These results demonstrate that PBA can be transported to the ALS model NSC-34 cell lines by sodium- and proton-coupled MCTs, and MA plays a vital role in the prevention of neurodegenerative diseases.