Nuclear and Membrane Receptors for Sex Steroids Are Involved in the Regulation of Delta/Serrate/LAG-2 Proteins in Rodent Sertoli Cells

Delta/Serrate/LAG-2 (DSL) proteins, which serve as ligands for Notch receptors, mediate direct cell-cell interactions involved in the determination of cell fate and functioning. The present study aimed to explore the role of androgens and estrogens, and their receptors in the regulation of DSL proteins in Sertoli cells. To this end, primary rat Sertoli cells and TM4 Sertoli cell line were treated with either testosterone or 17 beta-estradiol and antagonists of their receptors. To confirm the role of particular receptors, knockdown experiments were performed. mRNA and protein expressions of Jagged1 (JAG1), Delta-like1 (DLL1), and Delta-like4 (DLL4) were analyzed using RT-qPCR, Western blot, and immunofluorescence. Testosterone caused downregulation of JAG1 and DLL1 expression, acting through membrane androgen receptor ZRT- and Irt-like protein 9 (ZIP9) or nuclear androgen receptor (AR), respectively. DLL4 was stimulated by testosterone in the manner independent of AR and ZIP9 in Sertoli cells. The expression of all studied DSL proteins was upregulated by 17 beta-estradiol. Estrogen action on JAG1 and DLL1 was mediated chiefly via estrogen receptor alpha (ER alpha), while DLL4 was controlled via estrogen receptor beta (ER beta) and membrane G-protein-coupled estrogen receptor (GPER). To summarize, the co-operation of nuclear and membrane receptors for sex steroids controls DSL proteins in Sertoli cells, contributing to balanced Notch signaling activity in seminiferous epithelium.

Automated summary

This study investigates the role of androgens and estrogens, and their receptors, in regulating DSL proteins in Sertoli cells. The results show that testosterone downregulates JAG1 and DLL1 expression via membrane androgen receptor ZIP9 or nuclear androgen receptor AR, respectively. DLL4 expression is stimulated by testosterone independent of AR and ZIP9. On the other hand, 17β-estradiol upregulates the expression of all studied DSL proteins. Estrogen action on JAG1 and DLL1 is mediated chiefly via estrogen receptor alpha (ERα), while DLL4 is controlled via estrogen receptor beta (ERβ) and G-protein-coupled estrogen receptor (GPER).