Influence of Different Death Receptor Signaling Pathways on Apoptosis of Eimeria tenella Host Cells

The aim of this study was to investigate the regulatory roles of distinct signaling cascades within the death receptor pathway in host cell apoptosis induced by Eimeria tenella (E. tenella); to this end, primary chicken embryo cecal epithelial cell culture, gene silencing, enzyme-linked immunosorbent assay (ELISA), Hoechst–Annexin V/PI apoptosis staining, hematoxylin–eosin (HE) staining, and quantitative real-time polymerase chain reaction (qRT-PCR) were employed. At 4, 24, 72, and 120 h post-inoculation (hpi) with E. tenella sporozoites, the proportion of apoptosis in six treatment groups Group C, Group T0 (E. tenella infection group), Group T1 (E. tenella + Fas SiRNA), Group T2 (E. tenella + TRAIL SiRNA), Group T3 (E. tenella + TNFR1 SiRNA), and Group T4 (E. tenella + NC SiRNA) and the dynamic changes in Fas cell surface death receptor (Fas), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), tumor necrosis factor receptor 1 (TNFR1), TNF receptor-associated death domain (TRADD), Fas-associated death domain (FADD), and death domain-associated protein (Daxx) expression and caspase-8 activity in the cells were determined. The results demonstrated that, from 4 to 120 hpi, the Fas and TNFR1 mRNA expression levels in Group T0’s host cells were significantly higher than those in Group C (p TNFR1 signaling pathway > TRAIL signaling pathway.