Proteomic analysis of mechanisms of hypoxia-induced apoptosis in trophoblastic cells

Abstract

Preeclampsia is often accompanied by hypoxia of the placenta and this condition induces apoptosis in trophoblastic cells. The aim of this study was to characterize global changes of apoptosis-related proteins induced by hypoxia in trophoblastic cells so as to clarify the mechanism of hypoxia-induced apoptosis by using the PoweBlot, an antibody-based Western array. Human choriocarcinoma cell line JAR was cultured for 24 hours under aerobic and hypoxic conditions. Hypoxia induced apoptosis accompanied by increased expression of Bcl-x, Caspase-3 and -9, Hsp70, PTEN, and Bag-1. Bad, pan-JNK/SAPK-1, Bcl-2, Bid, and Caspase-8 showed decreased expression. Hypoxia-induced apoptosis was increased with the transfection of a bag-1 antisense oligonucleotide. The bag-1 antisense oligonucleotide affected the expression of Bid, Bad, Bcl-2, JNK, and phosphorylated JNK, although expression of PTEN and Bcl-X did not change. Bag-1 may inhibit apoptosis by suppressing the expression of Bid and Bad. It may also enhance apoptosis by inhibiting the expression of Bcl-2 and by modulating phosphorylation of JNK. Both mitochondrial and stress-activated apoptosis pathways played important roles in the hypoxia induced cell death of trophoblastic cells. These findings will contribute to establish new approach to detect hypoxic stress of the placenta, which leads to preeclampsia and other hypoxia-related obstetrics complications.

Expression Profile of C19MC microRNAs in Placental Tissue in Pregnancy-Related Complications

“…Hypoxia induces apoptosis in trophoblastic cells accompanied by increased expression of Caspase-3 (Ishioka et al, 2006). BCL2 B-cell CLL/lymphoma 2 This gene encodes an integral outer mitochondrial membrane protein that blocks the apoptotic death of some cells.…”

“…SMAD2 SMAD family member 2 Smad2 expression, the molecule involved in TGF-b1 signaling in the normal villous tree, is enhanced in placental tissues derived from severe fetal growth restriction-preeclampsia cases characterized by early onset and absent end diastolic velocities in the umbilical arteries (Todros et al, 2007). BID BH3-interacting domain death agonist Hypoxia induces apoptosis in trophoblastic cells accompanied by decreased expression of Bid (Ishioka et al, 2006).…”

Hypoxia-inducible regulation of placental BOK expression

“…Hypoxia down-regulates pro-apoptotic BID via HIF-1 in colon cancer cells [38], but down-regulation of proapoptotic BAD by hypoxia in these cells was independent of HIF-1. Both BID and BAD are down-regulated by hypoxia in the human choriocarcinoma cell line JAR [39]. Whether the decrease in BID and BAD expression in these trophoblastic cells occurs via either a HIF-dependent or -independent mechanism is unknown.…”

Proteomics Approaches in Pre-Eclampsia Research

“…42,43 In another study of placental tissue, Western blotting, a more traditional method for studying proteins was utilised as an array to characterise global changes of apoptosis-related proteins induced by hypoxia in trophoblastic cells. 44 The PowerBlot, an antibody-based Western array for apoptosis-related proteins, was used to detect proteins from a human choriocarcinoma cell line JAR, cultured for 24 hours under aerobic and hypoxic conditions. Hypoxia-induced apoptosis was accompanied by an increased expression of Bcl-x, Caspase-3 and -9, Hsp70, PTEN, and Bag-1.…”