Perez Gloria I, Jurisicova Andrea, Matikainen Tiina, Moriyama Toshitake, Kim Mee-Ran, Takai Yasushi, Pru James K, Kolesnick Richard N, Tilly Jonathan L
Vincent Center for Reproductive Biology, Vincent Obstetrics and Gynecology Service, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, USA.
FASEB J. 2005 May;19(7):860-2. doi: 10.1096/fj.04-2903fje. Epub 2005 Feb 23.
An age-dependent acceleration of apoptosis occurs in female germ cells (oocytes), and this requires communication between the oocyte and its surrounding somatic (cumulus) cells. Here we show in aged mice that ceramide is translocated from cumulus cells into the adjacent oocyte and induces germ cell apoptosis that can be prevented by sphingosine-1-phosphate. Trafficking of ceramide requires gap junction-dependent communication between the cumulus cells and the oocyte as well as intact lipid rafts. Further, the occurrence of the elevated incidence of apoptosis in oocytes of aged females is concomitant with an enhanced sensitivity of the oocyte to a spike in cytosolic ceramide levels, as well as increased bax mRNA and Bax protein levels. Thus, the force driving the age-related increase in female germ cell death is multifactorial, but changes in the intercellular trafficking of ceramide, along with hypersensitivity of oocytes to ceramide, are key factors in this process.
