Fig. 3.

Palmitate stimulates endoplasmic reticulum (ER) stress through a TLR4-dependent mechanism. HAECs were transfected with siRNA for TLR4 or scrambled and then incubated for 48 h. Cells were treated with palmitate (PA, 200 μM, 6 h), and total RNA (A) or cell lysate (B) was isolated. RNA was subjected to RT-PCR, and cell lysate was subjected to Western blotting. Treatment with palmitate stimulated splicing of XBP-1 and phosphorylation of eIF2α; knockdown of TLR4 blunted palmitate-stimulated XBP-1 splicing and phosphorylation of eIF2α. ***P < 0.001, **P < 0.01: samples are statistically different.