Characterization of cholesterol metabolism in Sertoli cells and spermatogenesis (Review)

Abstract

The Sertoli cell, which is the supporting cell of spermatogenesis, has an important role in the endocrine and paracrine control of spermatogenesis. Functionally, it provides the cells of the seminiferous epithelium with nutrition, conveys mature spermatids to the lumen of seminiferous tubules, secretes androgen-binding protein and interacts with endocrine Leydig cells. In addition, the levels of cholesterol, as well as its intermediates, vary greatly between nongonadal tissues and the male reproductive system. Throughout spermatogenesis, a dynamic and constant alteration in the membrane lipid composition of Sertoli cells occurs. In several mammalian species, testis meiosis-activating sterol and desmosterol, as well as other cholesterol precursors, accumulate in the testes and spermatozoa. In addition, certain cholesterogenic genes exhibit stage-specific expression patterns during spermatogenesis, including the cytochrome P450 enzyme lanosterol 14α-demethylase. Inconsistency in the patterns of gene expression during spermatogenesis indicates a cell-type specific and complex temporary modulation of lipids and cholesterol, which also implicates the dynamic interactions between Sertoli cells and germ cells. Furthermore, in the female reproductive tract and during epididymal transit, which is a prerequisite for valid fertilization, the modulation of cholesterol occurring in spermatozoal membranes further indicates the functional importance of sterol compounds in spermatogenesis. However, the exact role of cholesterol metabolism in Sertoli cells in sperm production is unknown. The present review article describes the progress made in the research regarding the characteristics of the Sertoli cell, particularly the regulation of its cholesterol metabolism during spermatogenesis.

Relevance of Fatty Acids to Sperm Maturation and Quality

“…Functionally, it provides the cells of the seminiferous epithelium with nutrition, conveys mature spermatids to the lumen of seminiferous tubules, secretes androgen-binding protein, and interacts with endocrine Leydig cells. Throughout spermatogenesis, a dynamic and constant alteration in the membrane lipid composition of Sertoli cells occurs [31].…”

Multiple aspects of male germ cell development and interactions with Sertoli cells require inositol hexakisphosphate kinase-1

“…Sertoli cells are “nurse” cells that influence the survival, replication, differentiation, and movement of germ cells via direct contact and by controlling the environment milieu within the seminiferous tubules 13 . Sertoli cells provide physical and nutritional support for germ cells 14 , 15 as well as secreting factors to control maintenance and self-renewal of spermatogonial stem cells 16 . Sertoli cells protect germ cells by forming the blood-testis barrier and expressing immunoregulatory factors, thereby creating a local tolerogenic environment optimal for survival of nonsequesetred auto-antigenic germ cells 17 .…”

Functional importance of palmitoyl protein thioesterase 1 (PPT1) expression by Sertoli cells in mediating cholesterol metabolism and maintenance of sperm quality

“…For instance, Sertoli cells provide a set of essential nutrients for germ cell survival and differentiation, including amino acids, carbohydrates, lipids and vitamins (Chojnacka, Zarzycka, & Mruk, ; Mruk & Cheng, ). Meanwhile, Sertoli cells are able to metabolize glucose into pyruvate and lactate, which is the preferential energy substrate for post‐meiotic germ cells to support their metabolic activity (Sèdes et al, ; Shi et al, ). In addition, Sertoli cells also participate in the secretion of components of the extracellular matrix necessary to maintain the integrity of the seminiferous epithelium and intercellular junctions (Sèdes et al, ; Shi et al, ).…”

“…Meanwhile, Sertoli cells are able to metabolize glucose into pyruvate and lactate, which is the preferential energy substrate for post-meiotic germ cells to support their metabolic activity (Sèdes et al, 2018;Shi et al, 2018). In addition, Sertoli cells also participate in the secretion of components of the extracellular matrix necessary to maintain the integrity of the seminiferous epithelium and intercellular junctions (Sèdes et al, 2018;Shi et al, 2018). In Sertoli cells, cell adhesion and junction formation undergo extensive Western blot analysis resolves palmitoyl protein thioesterase 1 (PPT1) expression in mouse testis and Sertoli cells.…”