Figure 1. Palmitate and LPS lead to synergistic cell death in macrophages.

(A, B) Peritoneal macrophages (pMACs, A) or RAW 264.7 cells (B) were stimulated with PBS or 50 ng/ml LPS in the presence of 250 μM palmitate (palm) complexed to BSA or in the presence of BSA alone. Cell death was assessed by annexin (ANX)-propidium iodide (PI) flow cytometry at 24 h on 10⁴ cells/sample. Graphs report cell death as percent of the total cells that were either ANX⁺/PI⁻ or ANX⁺/PI⁺. (C) Following stimulation of pMACS as indicated, LDH was quantified in the supernatant (sup) and is reported as absorbance at 492 nm and as percent of total cellular LDH (left panel). Total cellular LDH following lysis is shown for each of the treatments (right panel). (D) pMACs were stimulated with increasing concentrations of palm (left panel) or oleate (right panel) in the presence of PBS or LPS and cell death was assessed by LDH release. (E) pMACs were stimulated with palm and LPS in either high (4.5 g/L, white bars) or low (1 g/L, black bars) glucose media and cell death was determined by LDH release. (F) Rates of ¹⁴C-palm uptake (left panel) and oxidation (right panel) were determined following LPS stimulation. All experiments were performed a minimum of 3 times in triplicate. Bars represent the mean ± SE. *, p ≤ 0.05 for BSA vs. palm; #, p ≤ 0.05 for PBS vs. LPS; ns, non-significant.