Loss of function variant in CIP2A associated with female infertility with early embryonic arrest and fragmentation

Zhenxing Liu; Qingsong Xi; Meiqi Hou; Tingting Zou; Huihui Liu; Xiaopei Zhou; Lei Jin; Lixia Zhu; Xianqin Zhang

doi:10.1016/j.bbadis.2024.167228

Loss of function variant in CIP2A associated with female infertility with early embryonic arrest and fragmentation

Biochim Biophys Acta Mol Basis Dis. 2024 May 9;1870(6):167228. doi: 10.1016/j.bbadis.2024.167228. Online ahead of print.

Authors

Zhenxing Liu¹, Qingsong Xi², Meiqi Hou¹, Tingting Zou¹, Huihui Liu¹, Xiaopei Zhou¹, Lei Jin³, Lixia Zhu⁴, Xianqin Zhang⁵

Affiliations

¹ Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China.
² Oncology Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
³ Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
⁴ Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China. Electronic address: zhulixia027@163.com.
⁵ Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China. Electronic address: xqzhang04@hust.edu.cn.

PMID: 38734318
DOI: 10.1016/j.bbadis.2024.167228

Abstract

Background: Early embryonic arrest and fragmentation (EEAF) is a common cause of female infertility, but the genetic causes remain to be largely unknown. CIP2A encodes the cellular inhibitor of PP2A, playing a crucial role in mitosis and mouse oocyte meiosis.

Methods: Exome sequencing and Sanger sequencing were performed to identify candidate causative genes in patients with EEAF. The pathogenicity of the CIP2A variant was assessed and confirmed in cultured cell lines and human oocytes through Western blotting, semi-quantitative RT-PCR, TUNEL staining, and fluorescence localization analysis.

Findings: We identified CIP2A (c.1510C > T, p.L504F) as a novel disease-causing gene in human EEAF from a consanguineous family. L504 is highly conserved throughout evolution. The CIP2A variant (c.1510C > T, p.L504F) reduced the expression level of the mutant CIP2A protein, leading to the abnormal aggregation of mutant CIP2A protein and cell apoptosis. Abnormal aggregation of CIP2A protein and chromosomal dispersion occurred in the patient's oocytes and early embryos. We further replicated the patient phenotype by knockdown CIP2A in human oocytes. Additionally, CIP2A deficiency resulted in decreased levels of phosphorylated ERK1/2.

Interpretation: We first found that the CIP2A loss-of-function variant associate with female infertility characterized by EEAF. Our findings suggest the uniqueness and importance of CIP2A gene in human oocyte and early embryo development.

Funding: This work was supported by National Key Research and Development Program of China (2023YFC2706302), the National Natural Science Foundation of China (81000079, 81170165, and 81870959), the HUST Academic Frontier Youth Team (2016QYTD02), and the Key Research of Huazhong University of Science and Technology, Tongji Hospital (2022A20).

Keywords: CIP2A; Early embryonic arrest and fragmentation; Exome sequencing; Female infertility; Oocyte meiosis.