Oestrous cycle-dependent expression of Fas and Bcl2 family gene products in normal canine endometrium

Abstract

During the oestrous cycle canine endometrium undergoes cyclical cellular proliferation, apoptosis and differentiation. To study the regulation of endometrial apoptosis and proliferation events the expression of apoptosis-related genes was analysed by real-time polymerase chain reaction and cellular expression of their proteins was identified through immunohistochemistry. Cellular apoptosis and proliferation events were detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) and proliferation marker Ki67 immunostaining, respectively. The highest proliferative index was observed in the follicular phase (all endometrial cellular components) and at early dioestrus (basal glands). This was associated with a low apoptotic index and a strong expression of anti- (Bcl2) and pro-apoptotic proteins (Fas, FasL, Bax). Subsequently (Days 11-45 of dioestrus), basal glandular epithelium experienced the highest apoptotic index, coincidental with a decrease of Bcl2 expression and a low ratio of Bcl2/Bax transcription. An increase in the apoptotic index of crypts, stromal and endothelial cells was observed at late dioestrus and the beginning of anoestrus. These results indicate that pro- and anti-apoptotic proteins regulate the balance between cell proliferation and death in the canine endometrium during the oestrous cycle. High Bcl2 expression in both the follicular and early dioestrous phases stimulate glandular proliferation and prevent apoptosis but, in the non-pregnant uterus, a decrease in Bcl2 expression together with an increase in pro-apoptotic proteins induces apoptosis of basal glandular epithelium cells.

miR‐26a promoted endometrial epithelium cells (EECs) proliferation and induced stromal cells (ESCs) apoptosis via the PTEN‐PI3K/AKT pathway in dairy goats

“…Although the precise mechanism has not been fully clarified, Bcl‐2 expression may regulate the FAS/FASL apoptotic pathway (Henriques et al, ). In addition, FAS‐mediated apoptosis occurred in the regulation of human endometrial function (Harada et al, ; Otsuki, ).…”

miR-182 aids in receptive endometrium development in dairy goats by down-regulating PTN expression

“…Previous researchers believed there was a relationship of expression between anti- (Bcl2) and pro-apoptotic proteins (Fas, FasL, Bax), although the precise mechanism has not been fully clarified in canine endometrium [ 107 ]. Fas (also known as APO-1 or CD95), a tumor necrosis factor (TNF) superfamily receptor, is known to induce apoptotic cell death when it binds to FAS ligand (FasL) [ 108 ].…”

Testin was regulated by circRNA3175‐miR182 and inhibited endometrial epithelial cell apoptosis in pre‐receptive endometrium of dairy goats

“…Bcl-2 family proteins are critical regulators of programmed cell death and act by permeabilizing the mitochondrial outer membrane (Bagci, Vodovotz, Billiar, Ermentrout, & Bahar, 2006;Eissing, Waldherr, Allgöwer, Scheurich, & Bullinger, 2007;Gillies & Kuwana, 2014), and effectively promoting or inhibiting apoptosis by synthesizing anti-or pro-apoptotic proteins (Antonsson & Martinou, 2000;Dorjgochoo et al, 2013). Previously, researchers believed there was a relationship between expression of anti-apoptotic (Bcl-2) and pro-apoptotic proteins (Fas, FasL, Bax), although the precise mechanism of which has not been fully clarified in canine endometrium (Henriques et al, 2015). FAS-mediated apoptosis occurs in the regulation of human endometrial function, under hormonal regulation (Song, Rutherford, Naftolin, Brown, & Mor, 2002).…”