Germ–Somatic Cell Interactions Are Involved in Establishing the Follicle Reserve in Mammals

Abstract

Mammalian females are born with a finite reserve of ovarian follicles, the functional units of the ovary. Building an ovarian follicle involves a complex interaction between multiple cell types, of which the oocyte germ cell and the somatic granulosa cells play a major role. Germ–somatic cell interactions are modulated by factors of different cell origins that influence ovarian development. In early development, failure in correct germ–somatic cell communication can cause abnormalities in ovarian development. These abnormalities can lead to deficient oocyte differentiation, to a diminished ovarian follicle reserve, and consequently to early loss of fertility. However, oocyte–granulosa cell communication is also extremely important for the acquisition of oocyte competence until ovulation. In this paper, we will visit the establishment of follicle reserve, with particular emphasis in germ–somatic cell interactions, and their importance for human fertility.

Comparative single‐cell transcriptomic analysis reveals differences in signaling pathways in gonadal primordial germ cells between chicken ( Gallus gallus ) and zebra finch ( Taeniopygia guttata )

“…Neighboring somatic cells in the embryonic gonads can influence various biological characteristics of germ cells. [26][27][28] Thus, our results suggest that the intraembryonic environment of gonadal PGCs at the same developmental stage differs between zebra finch and chicken.…”

“…The proportion of gonadal cells other than germ cell in zebra finch was generally lower than that of chickens; however, the proportion of supporting cells was higher than that of chickens (Figure 1D,E). Neighboring somatic cells in the embryonic gonads can influence various biological characteristics of germ cells 26–28 . Thus, our results suggest that the intraembryonic environment of gonadal PGCs at the same developmental stage differs between zebra finch and chicken.…”

Directed differentiation of human iPSCs to functional ovarian granulosa-like cells via transcription factor overexpression

“…Ovarian development requires paracrine and juxtacrine interaction between cells from germline and somatic lineages ( Høyer et al, 2005 ; Albertini et al, 2001 ; Rodrigues et al, 2021 ; Su et al, 2004 ; Le Bouffant et al, 2010 ; Otsuka and Shimasaki, 2002 ; Hu et al, 2015 ). During embryonic development, the first cells committed to the germline appear at roughly 2–3 weeks post-fertilization (wpf), when primordial germ cells (PGCs) are specified from the posterior epiblast in response to bone morphogenetic protein (BMP) signaling ( Tang et al, 2016 ; Lawson et al, 1999 ; Kee et al, 2006 ; Hayashi et al, 2011 ).…”

Eya-controlled affinity between cell lineages drives tissue self-organization during Drosophila oogenesis

“…From invertebrates to vertebrates, oocytes develop within a germline cyst that is enveloped by somatic cells 4 . The germline cyst consists of the oocyte itself and so-called nurse cells 5 – 8 . The role of nurse cells is to supply the oocyte with essential materials during oogenesis, but eventually, nurse cells are removed to generate a single mature oocyte 6 , 7 , 9 .…”