NEK2 is essential for spindle assembly checkpoint regulation and cytoskeleton organization in porcine oocyte meiotic maturation.

NIMA-related kinase 2 (NEK2) is a serine/threonine kinase that plays crucial roles in cellular events such as centrosome separation, cell cycle progression, spindle assembly checkpoint (SAC) regulation, and microtubule stabilization. However, its regulatory function during oocyte meiotic maturation remains unclear. In this study, NEK2 activity was inhibited using the specific inhibitor MBM-55 to evaluate its role in oocyte meiotic maturation and early embryonic development. NEK2 depletion impaired multiple indicators associated with oocyte maturation and decreased the maturation rate. Mechanistic analysis suggested that NEK2 inhibition altered spindle organization and chromosome alignment, which may be associated with impaired kinetochore-microtubule (K-MT) interactions and altered SAC-associated signaling, collectively contributing to MI-stage arrest and increased aneuploidy. In addition, NEK2 deficiency impaired the actin network, reducing spindle migration, preventing the efficient repair of accumulated DNA damage and ultimately leading to apoptosis. NEK2 inhibition in oocytes reduced subsequent embryonic developmental competence, leading to a lower blastocyst formation rate. These findings demonstrate that NEK2 is a critical regulator of porcine oocyte meiotic maturation through its roles in SAC regulation, K-MT attachment, cytoskeletal dynamics, and the DNA damage response.