FIGURE 3.

Accumulation of DSBs in EBV-transformed lymphoblasts of HSAN1 patients. A, the de novo synthesis of DSBs was compared between EBV-transformed lymphoblasts from 12 HSAN1 patients (all C133W carriers) and six healthy controls. Lymphoblasts were cultured for 24 h in the presence of FB1, and lipids were extracted, base-hydrolyzed, and analyzed by LC-MS. SO was not detected in the lymphoblasts. B, sphingoid base levels in total lipid extracts of lymphoblasts from HSAN1 patients and healthy controls. Total cellular lipids were extracted and subjected to acid/base hydrolysis. The resulting free sphingoid bases were analyzed by LC-MS. No significant differences were seen in the total amounts of SA or SO, whereas the concentration of m17:0, m17:1, m18:0, and m18:1 was significantly higher in the HSAN1 lymphoblasts when compared with control cells. In A and B, p values ≤ 0.05 were labeled with *.