Advances in the roles and mechanisms of fibroblast growth factor family members in the self-renewal and differentiation of spermatogonial stem cells

The normal process of spermatogenesis constitutes the cornerstone of male fertility, wherein the maintenance and differentiation of spermatogonial stem cells (SSCs) are indispensable factors in regulating male fertility. Members of the fibroblast growth factor (FGF) family are requisite for the self-renewal and differentiation of SSCs. The core domain of FGF family members is composed of a conserved spherical or atypical β-trefoil structure, and these family members possess secretion function. These growth factors play a pivotal role in the development of organisms and in regulating cell proliferation, migration, and differentiation. Simultaneously, FGF family members regulate the process of self-renewal and differentiation of SSCs through mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathways. This article reviews the latest research advancements in the regulation of SSCs' self-renewal and differentiation by members of the FGF family, with the expectation of deepening the understanding of key events in the development and maintenance of the male reproductive system, thereby providing novel ideas and theoretical bases for the diagnosis and treatment of infertility caused by male reproductive disorders.