(81) NEK2 is required for porcine embryonic development via the AKT signaling pathway

Se-Been Jeon¹; Pil-Soo Jeong¹; Hyo-Gu Kang¹; Min Ju Kim¹; Ji Hyeon Yun¹; Eun Young Choi¹; Bong-Seok Song¹; Sun-Uk Kim^1,2; Bo-Woong Sim^1,2

1. Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Republic of Korea

2. Department of Functional Genomics, University of Science and Technology (UST), Daejeon, Republic of Korea

Abstract Text:

NIMA-related kinase 2 (NEK2) is a serine/threonine protein kinase that plays a role in the cell cycle regulation, differentiation, and DNA damage response in various cellular processes. In this study, we aimed to elucidate the mechanisms by which NEK2 inhibition affects porcine embryonic development. Treatment with JH295 (JH; a NEK2 inhibitor) significantly reduced the proportion of 2-cell, 4-cell, and blastocyst stages at 24, 48, and 144 h, respectively, compared to the control. Abnormal development was associated with decreased expression of zygotic genome activation-related genes (ZSCAN4, UBTFL1, SUPT4H1, and IBSP) and significantly reduced levels of EdU, EU, and OPP incorporation compared to the controls. Notably, the NEK2 inhibition significantly decreased the protein levels of p-AKT and AKT, as well as their mRNA expression levels. To investigate the relationship between NEK2 and AKT signaling pathways during porcine embryonic development, embryos were cultured with JH and/or the AKT activator SC79. Co-treatment with JH and SC79 significantly increased the proportions of 2-cell, 4-cell, and blastocyst stages at 24, 48, and 144 h, respectively, compared with the JH group. In addition, the total cell number decreased by NEK2 inhibition was restored by SC79 co-treatment. Co-treatment with SC79 also restored the expanded blastocyst rate and cell death rate to the control levels. Furthermore, SC79 co-treatment rescued the number of trophectoderm cells and the inner cell mass/trophectoderm ratio to the control levels. Inhibition of NEK2 was found to have a negative effect on DNA integrity, increasing DNA damage. Intriguingly, the increased DNA damage caused by NEK2 inhibition was restored by SC79 co-treatment. These findings demonstrate that NEK2 plays an essential role in porcine embryonic development by regulating the AKT signaling pathway.