Mammalian oocytes cannot perform the essential metabolic process of glycolysis and so rely on their companion cumulus cells to provide them with glycolysis products. To facilitate this, oocytes secrete paracrine factors that promote the expression of glycolytic enzymes, such as platelet phosphofructokinase (PFKP) and lactate dehydrogenase A (LDHA), in cumulus cells. John Eppig and colleagues now show that oocyte-derived BMP15 and FGF8 cooperatively promote Pfkp and Ldha expression and glycolysis in mouse cumulus cells (see ). In Bmp15-/- and Bmp15-/-Gdf9+/- mutant mice, both Pfkp and Ldhaexpression and glycolysis are reduced in cumulus cells. Moreover, oocytes from these mutant mice are unable to promote glycolysis in wild-type cumulus cells. The co-culture of cumulus cells (without an oocyte) with BMP15 and FGF8 promotes Pfkp and Ldha expression and glycolysis, whereas the co-culture of cumulus cells with GDF9 and either BMP15 or FGF8 does not induce glycolysis. Understanding how BMP and FGF signals cooperate in this setting will clarify our knowledge of oocyte and follicular development.
