Transferrin is well known as an iron transport glycoprotein. Dimeric or tetrameric transferrin forms have recently been reported to modulate phagocytosis by human leukocytes. It is mainly synthesized by the liver, and also by other sources, such as Sertoli cells of the testis. Sertoli cells show a strong phagocytic activity toward apoptotic germ cells and residual bodies. Here, we provide evidence that purified human dimeric transferrin from commercial sources decreased residual body phagocytosis, unlike monomeric transferrin. The presence of iron appeared essential for dimeric transferrin inhibitory activity. Importantly, dimeric transferrin could be visualized by immunoblotting in Sertoli cell lysates as well as in culture media, indicating that dimeric transferrin could be physiologically secreted by Sertoli cells. By siRNA-mediated knockdown, we show that endogenous transferrin significantly inhibited residual body ingestion by Sertoli cells. These results are the first to identify dimeric transferrin in Sertoli cells and to demonstrate its implication as a physiological modulator of residual body phagocytosis by Sertoli cells.
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1 April 2008
Dimeric Transferrin Inhibits Phagocytosis of Residual Bodies by Testicular Rat Sertoli Cells
Marina G. Yefimova,
Amina Sow,
Isabelle Fontaine,
Vincent Guilleminot,
Nadine Martinat,
Pascale Crepieux,
Sylvie Canepa,
Marie-Christine Maurel,
Sophie Fouchécourt,
Eric Reiter,
Omar Benzakour,
Florian Guillou
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Biology of Reproduction
Vol. 78 • No. 4
April 2008
Vol. 78 • No. 4
April 2008
phagocytosis
residual bodies
Sertoli cells
testis
transferrin