Differentiation of Uniparental Human Embryonic Stem Cells into Granulosa Cells Reveals a Paternal Contribution to Gonadal Development

Introduction: Genomic imprinting is presented in mammals as a parent-of-origin dependent monoallelic expression of a subset of genes and is considered to stand behind the mammalian requirement for sexual reproduction. Nonetheless, the relative contribution of the maternal versus the paternal genome to the formation of the various tissues during human development is not fully understood. To this regard, androgenetic and parthenogenetic human pluripotent stem cells (hPSCs) are uniparental hPSCs which contain only paternal or maternal genomes, respectively, and thus serve as powerful tools to study the involvement of imprinted genes during embryogenesis.

Aims: To analyze the role of parental imprinting in the differentiation of hPSCs into gonadal granulosa cells.

Methods: Uniparental hPSCs were differentiated into granulosa-like cells (GLCs), which constitute part of the somatic female gonad, followed by a transcriptome analysis.

Results: We show that while both biparental and androgenetic hPSCs show a high differentiation potential, parthenogenetic hPSCs present a reduced capacity to differentiate into GLCs. We further identify the paternally expressed gene IGF2 as the most upregulated imprinted gene during granulosa differentiation. Remarkably, while androgenetic cells that harbor an IGF2 knock-out mutation fail to properly differentiate into GLCs, the differentiation efficiency of parthenogenetic cells supplemented with IGF2 is partly rescued.

Conclusions: Our findings unravel an essentiality for paternally expressed genes to the development of the female reproductive system. These findings could pave the road for the development of improved differentiation protocols for both research and medical applications.