Chicken coccidiosis inflicts severe economic losses on the poultry industry. The mechanisms underlying Eimeria tenella ( E. tenella ) invasion, colonization, and damage to host cells remain incompletely elucidated. This study was designed to elucidate Et MIC2-interacting proteins and the mechanism that EtMIC2 regulates E. tenella invasion and host cell apoptosis. His pull-down-MS and KEGG enrichment results showed apoptosis-related proteins including ITGAV (Integrin alpha-V), PlexinB2, MAP2K6, GNA11, TRK, CASP7, PAK1, and RAP1b. Only the interaction model between EtMIC2 and ITGAV met the AlphaFold2 thresholds (pLDDT > 70, pTM+ipTM > 0.75). The CO-IP results showed that in the primary host cells (CECs) of E. tenella , protein bands corresponding to Et MIC2 (50 kDa) and ITGAV (135 kDa) were successfully detected in the IP group. Blue colony growth on SD/-Ade,-His,-Leu,-Trp/X-α-Gal plates for the group pGBKT7-EtMIC2 or pGBKT7- Et MIC2-3 (153-1029 bp) or pGBKT7- Et MIC2-5 (855-1029 bp) co-transformed with pGADT7-ITGAV in Yeast Two-Hybrid assay. Green fluorescence was observed in DF-1 cells pBiFC-EtMIC2-VN173 or pBiFC-EtMIC2-3-VN173 or pBiFC-EtMIC2-5-VN173 were co-transfected with pBiFC-ITGAV-VC155 in Bimolecular fluorescence complementation. The addition of EtMIC2 protein significantly increased (P < 0.05) E. tenella infection rate, gene expression and protein activity of ITGAV , FAK , PLC , PKC , p65 , PI3K , Akt , ERK , and Bcl2, and reduced host cell Caspase 3 activity, apoptosis rate, gene expression and protein activity of JNK , p38 , Bax , and Caspase 3. Knockdown of ITGAV produced the opposite effects. The function of Et MIC2 was prevented following the knockdown of ITGAV . The above finding indicate that the EtMIC2 855-1029 bp (285-342 aa) region interacts with ITGAV, leading to the upregulation of ITGAV, FAK, PLC, PKC, p65, PI3K, Akt, ERK , and Bcl2 , while downregulating JNK, p38, Bax , and Caspase 3 , thereby promoting E. tenella invasion and inhibiting host cell apoptosis.
Cui et al. (Wed,) studied this question.