Proapoptotic role of human growth and transformation-dependent protein in the developing rat brain after hypoxia-ischemia.

Abstract

Human growth and transformation-dependent protein (HGTD-P) is a new proapoptotic protein and an effector of cell death induced by hypoxia-ischemia (HI). The function of HGTD-P has been investigated in human prostate cancer cells and mouse neurons cultured in vitro. However, whether HGTD-P is involved in regulating the apoptosis of rat neurons is not clear, and the relevance of HGTD-P in HI animal models is still unknown. Therefore, in the present study, we tried to elucidate the role that HGTD-P plays in apoptosis of rat neurons subjected to HI, both in culture and in the developing rat brain in vivo. Samples from primary cultured neurons and postnatal day 10 rat brains with HI were collected. RT-PCR, Western blotting, and immunocytochemistry were used to detect the expression and distribution of rat HGTD-P, cleaved caspase 3, and apoptosis- inducing factor (AIF). MTT assay, DAPI, TUNEL, and flowcytometry were used to detect cell viability and apoptosis. We found that HI upregulated the mRNA and protein levels of HGTD-P in rat neurons in vitro and in vivo. Antisense oligonucleotides (AS) targeted to HGTD-P inhibited the expression of HGTD-P, thus rescuing neuronal viability and attenuating neuronal apoptosis. In addition, we found that HGTD-P played its proapoptotic role by activating caspase 3 and inducing the translocation of AIF to nuclear. Our findings show that HGTD-P plays a proapoptotic role in the developing rat brain after HI and that it may be a potential target in treating HI-induced brain damage.