Authors: M De Falco V Fedele L Cobellis A Mastrogiacomo S Leone D Giraldi B De Luca V Laforgia A De Luca
Publish Date: 2004/10/02
Volume: 318, Issue: 3, Pages: 599-608
Abstract
The balance between cell death and cell proliferation and its regulation are essential features of many physiological processes and are particularly important in fetal morphogenesis and adult tissue homeostasis Apoptosis is a type of cell suicide that is activated in two main ways through a receptormediated pathway or through a mitochondrial pathway We have investigated the immunohistochemical distribution of proteins belonging to these two pathways in human placenta during gestation by comparing their expression levels between the first and third trimester of gestation In the first trimester the receptormediated pathway prevails over the mitochondrial pathway with a moderate/intense expression of its three components viz Fas ligand FasL Fas and caspase8 and weak positivity of antiapoptotic FLIP these proteins being mainly localized in the cytotrophoblast compartment In the third trimester of gestation there is an increased expression of mitochondrial pathway proteins viz Apaf1 and caspase9 We have also investigated the expression level of caspase3 the primary effector caspase of both pathways and have observed that it is moderately expressed during gestation being mainly localized in the cytotrophoblast during the first trimester and in both placental compartments during the third trimester of gestation Thus both pathways actively function in human placenta to execute cell death By means of immunoelectron microscopy we have further shown that in human placenta the two proteins of the mitochondrial pathway together with caspase3 are localized both in the cytoplasm and in the nucleus In particular Apaf1 and caspase9 are distributed near to the nuclear envelope suggesting an important role for these two proteins in disrupting the nuclear–cytoplasmic barrier
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