Lipid-reactive aPLs induce PAR1/PAR2 heterodimer signaling. (A) WT C57BL/6J mononuclear cells were treated for 15 minutes with the indicated inhibitors and stimulated for 15 minutes with FITC-labeled IgG or aPL HL5B for live cell imaging. (B) TF-thrombin-dependent Tnfα mRNA induction by aPL signaling in mouse CD115⁺ splenocytes; mean ± SD. n = 6. *P < .0001; 1-way ANOVA, Dunnett multiple-comparison test compared with WT sample. (C-D) Tnfα mRNA induction by aPL HL5B normalized to control IgG stimulated cells in PAR1^−/−, PAR1, or PAR2 cleavage-resistant spleen mononuclear cells with the indicated inhibitors; mean ± SD. n = 6. *P < .0001; **P = .044; 1-way ANOVA, Dunnett multiple-comparison test. (E-G) Tnfα mRNA induction after 3 hours of stimulation with aPL HL7G in CD115⁺ spleen monocytes from WT mice or the indicated mouse strains treated with the indicated inhibitors.