Fig. 8.

Effect of tyloxapol on binding of chylomicrons to LPL. A: Chylomicrons (20 μg/ml) were mixed with 2 or 8 mg/ml tyloxapol (tylox) and then incubated with largeBiT-LPL bound to smallBiT-GPIHBP1-expressing RHMVECs at 37°C. After 30 min, cells were washed, substrate was added, and luminescence was read. Bars represent luminescent signal (mean ± 95% CI of four independent experiments; n = 4 per group per experiment) normalized to the no chylomicron no tyloxapol control. B: Immunofluorescence showing binding of LPL and chylomicrons (chylos) to smallBiT-GPIHBP1-expressing RHMVECs. RHMVECs were incubated with largeBiT-LPL for 3.5 h at 4°C. After washing away unbound LPL, cells were incubated with or without with 20 µg/ml fluorescently labeled chylomicrons (green) for 30 min at 37°C, then with or without 8 mg/ml tyloxapol for 30 min at 37°C. Cells were then stained for LPL (red) using an antibody against the Flag tag and with DAPI (blue). C: Distribution of chylomicron diameters before (baseline) and after 30 min treatment with 8 mg/ml tyloxapol as measured by dynamic laser light scattering. Untreated chylomicrons stored at 4°C for 30 min after baseline reading were also analyzed (30 min untreated). Lines represent mean ± range (shaded area) particle distribution of three different reads.