TRADD is Involved in Apoptosis Induction in Granulosa Cells during Atresia in Pig Ovaries.

Abstract

Previously, we histochemically demonstrated the expression of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and its receptors, death receptor-4 (DR4), death receptor-5 (DR5) and decoy receptor-1 (DcR1) in granulosa cells of porcine follicles. However, TRAIL can induce both cell death and cell proliferation. In the present study, reverse transcription polymerase chain reaction and in situ hybridization analyses revealed increased mRNA expression of TNF receptor-associated death domain protein (TRADD), which transmits the death signal from DR4 and/or DR5 to intracellular apoptosis-signal transduction components, in granulosa cells was demonstrated only in atretic follicles but not in healthy follicles. These findings indicate that TRADD is involved in induction of apoptosis in granulosa cells, and that the TRAIL-receptor system induces apoptosis in granulosa cells during atresia in porcine ovaries.