Steroid hormones and human choriogonadotropin influence the distribution of alpha6-integrin and desmoplakin 1 in gland-like endometrial epithelial spheroids

Abstract

In human glandular endometrial epithelial cells, desmosomal and adherens junction proteins have been shown to extend from a subapically restricted lateral position to the entire lateral membrane during the implantation window of the menstrual cycle. Similarly, a menstrual cycle stage-dependent redistribution of the extracellular matrix adhesion protein α6-integrin has been reported. These changes are believed to be important for endometrial receptiveness and successful embryo implantation. To prove the hypothesis that steroid hormones and human choriogonadotropin can induce the redistribution of these adhesion molecules, we used the human endometrial cell line Ishikawa in a 3D culture system. Gland-like spheroids were grown in reconstituted basement membrane (Matrigel™). The lumen-bearing spheroids were treated for 2 or 4 days with ovarian steroids or human choriogonadotropin and then assessed by immunofluorescence microscopy. In addition, human endometrial biopsies were obtained from patients, who were in therapy for assisted reproductive technology, and were examined in parallel. Lateral redistribution of the desmosomal plaque protein desmoplakin 1 was observed in the spheroids treated either with progesterone, medroxyprogesterone acetate or human choriogonadotropin. Furthermore, the extracellular matrix adhesion protein α6-integrin showed an increased lateral membrane localization upon gestagen stimulation in the 3D culture system. The results of this study demonstrate that the 3D endometrial Ishikawa cell culture might be suited as an experimental model system to prove the effect of hormonal changes like those occurring during the window of implantation.

How Mechanical Forces Change the Human Endometrium during the Menstrual Cycle in Preparation for Embryo Implantation

“…Overall, the rearrangement of the junctional complex may weaken cell-cell adhesion and prepare the endometrium for trophoblast invasion. Comparable alterations of junctional rearrangements were also observed in 3D in vitro cell models [26] (see also Figure 4). Thus, a redistribution of desmosomes and adherens junctions was documented in response to estrogen, progesterone, and a combination of both in 3D acini prepared from the moderately polarized endometrial epithelial cell line Ishikawa [26].…”

“…The partial epithelial-to-mesenchymal transition presumably reduces the barrier function of the endometrium for the embryo to implant. Manifestations of the structural and functional transition in the human endometrium include the downregulation of N-cadherin [18], changes in apical marker enzyme expression [19,20], the reduction of apical microvilli [21] with the development of large apical membrane protrusions referred to as pinopodes [22], increased plasma membrane tortuosity [23], cytoskeletal reorganization [6,24,25], changes in cell-extracellular matrix contacts [26], and the rearrangement of the tripartite junctional complex [27,28] (Figure 3).…”

In focus in HCB

“…In this regard, in earlier published work, Buck and colleagus used immunofluorescence microscopy to investigate the localization and distribution of endometrial epithelial junction proteins during the human menstrual cycle (Buck et al 2012), and further demonstrated the great utility of creating and using endometrial spheroids as a model system for studying human embryo implantation (Buck et al 2015). In their current investigation, Buck et al (2021) continue their use of the endometrial spheroid model to investigate the effect of steroid hormones and human choriogonadotropin on the polarity-inducing localization of cellular adhesion proteins. They created spheroid cultures from the Ishikawa human endometrial cell line, treated them with ovarian steroids or human choriogonadotropin, and then performed multilabel immunostaining followed by wide-field light microscopic imaging.…”

“…Among the various repair components and mechanisms, different chloride channels may be involved since they play a role in keratinocyte migration, proliferation, and differentiation (Dong et al 2015;Guo et al 2016;Pan et al 2015) as well as tumor suppression (Zhang et al 2013). The activity of the chloride channels seems to be regulated by various chloride channel accessory proteins (Patel et al 2009) that are also present in epidermal keratinocytes (Braun et al 2010;Connon et al 2004). Through their regulatory effect, they can modulate cell proliferation and apoptosis, and via their integrin-binding domains, they can promote cell adhesion and control migration and invasion.…”

“…E2 estradiol, P4 progesterone, Zonula occludens protein-1 (ZO-1, red) and DAPI (blue). FromBuck et al (2021)…”