Regulation of glypicanâ1, syndecanâ1 and syndecanâ4 mRNAs expression by follicleâstimulating hormone, cAMP increase and calcium influx during rat Sertoli cell development
2002
Brucato, Sylvie | Bocquet, Jean | Villers, Corinne
In seminiferous tubules, Sertoli cells provide structural and nutritional support for the developing germinal cells. Cellâ toâcell signaling and cell adhesion require proteoglycans expressed at the cell membrane. A preliminary biochemical and structural approach indicated that cell surface proteoglycans are mostly heparan sulfate proteoglycans (HSPG). Glypicanâ1, syndecansâ1 and â4 were identified using a molecular approach. Their differential regulation was demonstrated in immature rat Sertoli cells. Follicleâstimulating hormone (FSH) is the main regulator of Sertoli cell function. Signal transduction triggered by FSH involves both an increased intracellular cAMP synthesis and a calcium influx. This study demonstrates that FSH, through its second messengers (increase in intracellular cAMP and intracellular calcium), downregulated the glypicanâ1 mRNA expression in Sertoli cells from 20âdayâold rats. On the other hand, syndecanâ1 mRNA expression is not modulated by FSH as it would result from the antagonistic effects of increased intracellular cAMP and intracellular calcium levels. Finally, syndecanâ4 mRNA expression is not regulated by this pathway. The present study was extended during Sertoli cell development. Indeed, Sertoli cells undergo extensive changes during the postnatal period both in structure and function. These important transformations are critical for the establishment of spermatogenesis and development of the adult pattern of testicular function. Our data indicated that the regulation of HSPG mRNA expression is HSPGâspecific and depends on the Sertoli cell developmental stage.
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