Dimeric transferrin inhibits phagocytosis of residual bodies by testicular rat Sertoli cells.
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.
Yefimova
Marina G
MG
Laboratoire de Physiologie de la Reproduction et des Comportements, UMR 6175 INRA-CNRS-Université de Tours-Haras Nationaux, Centre de Recherches de Tours, 37380 Nouzilly, France.
Sow
Amina
A
Fontaine
Isabelle
I
Guilleminot
Vincent
V
Martinat
Nadine
N
Crepieux
Pascale
P
Canepa
Sylvie
S
Maurel
Marie-Christine
MC
Fouchécourt
Sophie
S
Reiter
Eric
E
Benzakour
Omar
O
Guillou
Florian
F
D000818:Animals; D002478:Cells, Cultured; D019281:Dimerization; D006801:Humans; D015151:Immunoblotting; D007501:Iron / Q000494:pharmacology / Q000502:physiology; D008297:Male; D010587:Phagocytosis / Q000187:drug effects*; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D012708:Sertoli Cells / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D013329:Structure-Activity Relationship; D014162:Transfection; D014168:Transferrin / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*
D034741:RNA, Small Interfering; D014168:Transferrin; D007501:Iron