4-MU treatment altered TP protein and mRNA expression levels in HRA cells. (A) Western blot showed a reduction of TP protein in a dose-dependent manner of 4-MU. MW abbreviated molecular weight. (B) 4-MU administration significantly reduced the TP mRNA expression level in HRA cells (left panel), whereas there was no significant difference in HAS3 expression between HRA cells cultured with and without 4-MU (right panel). The relative expression of TP and HAS3 mRNA was analyzed by qRT-PCR in HRA cells cultured with or without 1.0 mM 4-MU for 24 hours. The data presented are the average ± SD of the relative mRNA expression values normalized to the 18S rRNA amount (*indicates P = 0.0005 compared with control).