A preliminary report on spinal muscular atrophy lymphoblastoid cell lines: Are they an appropriate tool for drug screening?

Introduction: Spinal muscular atrophy (SMA) is a neurodegenerative disease of the motor neurons that results in progressive muscle weakness. It is also the leading hereditary cause of infant mortality. Homozygous loss of the survival motor neuron (SMN1) gene causes SMA, and the number of copies of the SMN2 gene modulates the severity of the disease. Increasing the expression of the SMN2 gene by pharmacological agents is one of the therapeutic approaches currently being implemented. Methods: In this preliminary study, we investigated the effect of phenylbutyrate, a histone deacetylase (HDAC) inhibitor, on SMN2 expression in two SMA type III Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines to understand the suitability of lymphoblastoid cell lines in drug screening. These cell lines are regarded as a good source as they can easily be established from the peripheral leucocytes of patients. Quantitative analysis of SMN2 mRNA was performed on established cell lines treated with various concentrations of phenylbutyrate and for a range of incubation periods using real-time polymerase chain reaction. Western blot analysis was used to determine SMN protein levels. Results: Real-time polymerase chain reaction and Western blot analysis demonstrated that the levels of SMN2 full-length (fl-SMN2) transcripts and protein were not increased in phenylbutyrate-treated cell lines compared to non-treated controls. Conclusion: These results suggest that EBV-transformed lymphoblastoid cell lines are not suitable for studying the effect of certain HDAC inhibitors on SMN2 gene expression.