Genetic deletion of caspase-8 rescues TAK1 inactivation–induced inflammatory cell death of myeloid cells, and FADD deletion rescues TAK1-deficient mice from the pathophysiology of sepsis. (A) Cell death detected by IncuCyte image analysis of BMDMs treated with vehicle or LPS + z-VAD. BMDMs were obtained fromLyz2^cre+ ×Tak1^f/+,Lyz2^cre+ ×Tak1^f/+ ×Ripk1^KD/KD, andLyz2^cre+ ×Tak1^f/f ×Ripk1^KD/KD mice and assessed in culture at 12 h after stimulation. Green with red circles indicates dead-cell positivity for the SYTOX Green stain. Scale bar, 50 µm.(B) Western blot analysis of MLKL protein expression and oligomerization from BMDMs prepared fromLyz2^cre+ ×Tak1^f/+,Lyz2^cre+ ×Tak1^f/f,Lyz2^cre+ ×Tak1^f/f ×Ripk1^KD/KD, andLyz2^cre+ ×Tak1^f/f ×Mlkl^−/− mouse strains that were treated with vehicle control, TNF + z-VAD, or LPS + z-VAD. (C) Histopathologic analysis by hematoxylin and eosin–stained sections of livers from WT littermate controls,Ripk3^−/−,Ripk3^−/− ×Casp8^−/−, andRipk3^−/− ×Fadd^−/− mice 6 h after LPS + TAK1-i–induced septic shock. Yellow arrows indicate focal granulocytic infiltration. Scale bars, 50 µm. n = 3. Data are representative of three (A) or two (B and C) independent experiments.