Megan Lawler

Peroxisome biogenesis disorders (PBDs) are conditions in which peroxisomes are dysfunctional or completely absent from patient cells due to mutations in the PEX gene family. These disorders are characterized by drastically shortened lifespans, but there are currently no standard treatments. Previous studies demonstrate that 4-phenylbutryic acid (PBA) shows pharmaceutical promise with PBDs with results suggesting PBA treatment increases peroxisome count in HepG2 cells. Using flow cytometry analysis of cells with fluorescently tagged peroxisomes, this study attempted to expand these findings by investigating the OP9 and C1498 cell lines and comparing results to those seen in the HepG2 line. Looking at PBA treatment in different cell types, including those from different species, could provide evidence that this drug is effective on cells in multiple organ systems and justification for future testing in animal models of PBDs. In this study, OP9 cells showed a significant increase in fluorescence intensity, suggestive of a higher peroxisome count, after a 48-hour PBA treatment with the maximum increase observed at a 4 mM drug concentration. The C1498 cell line also showed an increase in fluorescence for some PBA concentrations with the optimal concentration being around 1 mM, but cell viability suffered and higher proportions of cells were tagged for fluorescence in the higher drug concentration treatments in comparison to the control samples. These findings, along with Western blot and qPCR results, point to another mechanism leading to the increase in mean fluorescence values for OP9 and C1498 cells after PBA treatment rather than the originally proposed increase in peroxisome number.