Figure 3.

UQ content in the skin fibroblasts from the L111P COQ7 patient. (A) HPLC chromatograms of quinone extracts from human skin fibroblasts. The L111P patient's cells showed ~ 30% decrease in UQ₁₀ level and accumulation of the biosynthetic precursor DMQ₁₀. Treatment of the patient cells with 1.5 mM DHB abolished the accumulation of DMQ₁₀, but did not significantly increase UQ₁₀ level. Cells with the same amount of protein (2.5 mg) were used for quinone extraction and HPLC quantitation. See Figure S2 for further verification of the peak identities. (B) Quinone levels expressed as HPLC‐UV peak area normalized to protein content. **P < 0.01 (Student's t‐test). (C) Quinone levels in the L111P skin fibroblasts after treatment with different doses of DHB for 7 days. N.D.: Not detected. Data represent the mean ± S.E.M. of 2–3 independent samples. Two‐way anova followed by Dunnett's post‐test revealed no statistically significant group difference in UQ₁₀ concentrations.