Heme inhibits platelet complex V activity to induce mtROS production and TSP-1 release via TLR4. (A) Platelet mitochondrial complex V activity, (B) MitoSOX fluorescence, and (C) thrombospondin-1 levels in the releasate were measured in heme-treated platelets in the presence or absence of TLR4 neutralizing antibody (5 μg/mL), pharmacological inhibitors of TBK1 (2 μM of BX795), IRAK1/4 (100 nM of N-[1-[2-(4-Morpholinyl)ethyl]-1H-benzimidazol-2-yl]-3-nitrobenzamide), TAK1 (5 nM of (5Z)-7-Oxozeaenol). Data are represented as Mean ± SEM. ****p < 0.0001, ***p < 0.001, **p < 0.01. n = 4.