Regulatory role of BMP2 and BMP7 in spermatogonia and Sertoli cell proliferation in the immature mouse.
OBJECTIVE
The aim of this study was to determine the action of bone morphogenetic proteins (BMPs) on testicular cell proliferation during early postnatal life, a definite developmental time at which crucial changes in germ cell and Sertoli cell maturation occur.


METHODS
We investigated the effect of BMP2 and BMP7, two factors which belong to the relatively distant decapentaplegic (DPP) and 60 A classes of the large BMP family, upon spermatogonial and Sertoli cell proliferation, and we examined the expression of activin/BMP type II and type I receptors. We used in vitro cultured testis fragments from 7-day-old mice, highly purified populations of somatic and germ cells and total testes from mice of different ages. Cell proliferation was assessed by BrdU labelling and [3H]-thymidine incorporation. Ribonuclease protection assays and Northern blotting were performed to analyse receptor expression.


CONCLUSIONS
We have demonstrated a stimulatory action of BMP2 and BMP7 in spermatogonia and Sertoli cell proliferation respectively. ActRIIB is the type II receptor expressed most in spermatogonia, whereas Sertoli cells specifically expressed BMPRIIB, in addition to ActRIIB. By contrast, the presence of ActRIIA was undetectable in either germ or somatic cells. The type I receptors ActRIA, ActRIB and BMPRIA were all found in both cell types, indicating that the observed effect of BMP2 and BMP7 on testicular cell proliferation may be mediated by a number of combinatorial interactions in the receptor complexes. These findings suggest that BMPs are involved in physiological paracrine signalling during the first wave of spermatogenesis.
Department of Histology and Medical Embryology, University of Rome 'La Sapienza', Rome, Italy.
Rossella
R
Puglisi
Micaela
M
Montanari
Pieranna
P
Chiarella
Mario
M
Stefanini
Carla
C
Boitani
D029404:Activin Receptors / Q000235:genetics / Q000378:metabolism; D000367:Age Factors; D000818:Animals; D000963:Antimetabolites; D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7; D052004:Bone Morphogenetic Protein Receptors; D019485:Bone Morphogenetic Proteins / Q000378:metabolism* / Q000494:pharmacology; D001973:Bromodeoxyuridine; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009924:Organ Culture Techniques; D019899:Paracrine Communication / Q000502:physiology; D017978:Receptors, Growth Factor / Q000235:genetics / Q000378:metabolism; D012708:Sertoli Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013093:Spermatogonia / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000254:growth & development; D013936:Thymidine / Q000493:pharmacokinetics; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology; D014316:Tritium
D000963:Antimetabolites; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D017978:Receptors, Growth Factor; D016212:Transforming Growth Factor beta; D014316:Tritium; D029404:Activin Receptors; D052004:Bone Morphogenetic Protein Receptors; D001973:Bromodeoxyuridine; D013936:Thymidine