Research data from C. Johnson and colleagues update understanding of apoptosis
December 29th, 2008
2008 DEC 29 -- "This study investigates the role of caspase 2 in apoptotic signaling of nonhuman primate male germ cells triggered by mild testicular hyperthermia, testosterone (T-e) implants, or by combined interventions. Mean incidence of germ cell apoptosis increased significantly by Day 3 in the heat (H-e) alone group and by Day 8 in the T-e alone group but peaked at Day 3 in H-e + T-e group," scientists in the United States report.
"We found activation of caspase 2 in both germ cells and Sertoli cells after induction of apoptosis. Most notably, active caspase 2 immunoreactivity was detected only in those germ cells susceptible to apoptosis compared with controls, where little or no such staining is detected. To further explore the role of caspase 2 in regulating male germ cell death, we next evaluated the efficacy of caspase 2 inhibition in preventing or attenuating heat-induced germ cell apoptosis in rats. Caspase 2 inhibition significantly (P < 0.05) prevented such heat-induced germ cell apoptosis. The protection offered by the caspase 2 inhibitor occurred upstream of mitochondria, involving suppression of mitogen-activated protein kinase (MAPK) 14 activation and inducible nitric oxide synthase (NOS2) induction and, in turn, suppression of cytochrome c-mediated death pathway. Together, our results show that caspase 2 is activated in male germ cells undergoing apoptosis in nonhuman primates after heat stress, hormonal deprivation, or after combined interventions," wrote C. Johnson and colleagues.
The researchers concluded: "Blockade of caspase 2 activation prevents heat-induced germ cell apoptosis in rats by suppressing the MAPK14- and NO-mediated intrinsic pathway signaling."
Johnson and colleagues published their study in Biology of Reproduction (Role of Caspase 2 in Apoptotic Signaling in Primate and Murine Germ Cells. Biology of Reproduction, 2008;79(5):806-814).
For additional information, contact A.P.S. Hikim, UCLA, David Geffen School Medical, Harbor UCLA Med Center, Division Endocrinol, Dept. of Medical, Box 446, 1000 W Carson St., Torrance, CA 90509, USA.
The publisher's contact information for the journal Biology of Reproduction is: Society Study Reproduction, 1603 Monroe St., Madison, WI 53711-2021, USA.
