Expression of stathmin in human uterus and decidualizing endometrial stromal cells

Abstract

The cytosolic phosphoprotein stathmin is upregulated at the site of embryo implantation in the rodents. However, stathmin expression in the human uterus has not yet been investigated. The distribution of uterine and placental stathmin was analyzed by immunohistochemistry, while stathmin mRNA expression was detected in endometrial tissues by the reverse transcriptase-PCR. Cultured endometrial stromal cells were used to investigate whether stathmin plays a role in decidualization. Stathmin is expressed specifically in the glandular epithelium and the stromal cells of human endometrial tissue. It is also expressed by cytotrophoblasts and extravillous trophoblasts, but not by syncytiotrophoblasts or decidual tissues during the first trimester of pregnancy. When stromal cells isolated from normal endometrial tissues were cultured and stimulated to decidualize by progesterone (P4) plus estrogen or dibutyryl cyclic 3 0 ,5 0 -AMP, their total and phosphorylated stathmin levels decreased. Knocking down stathmin expression in the cultured stromal cells using small interfering RNA, before the cells were exposed to the decidualizing agents, significantly suppressed decidualization, as indicated by the decreased expression of IGF-binding protein-1 and prolactin. Stathmin is differently expressed in human endometrial and placental cells and may participate in the decidualization of endometrial stromal cells.

Reduced Stathmin-1 Expression in Natural Killer Cells Associated with Spontaneous Abortion

“…Stathmin silencing in primary stromal cells using small interfering RNA before the cells are exposed to decidualizing agents also markedly suppresses decidualization, suggesting that stathmin may play a key role in decidualization. 6 Stathmin overexpression favors microtubule destabilization, whereas decreased stathmin expression favors elongated, bundled microtubules and an increased ratio of polymerized to soluble tubulin. 23 Immunohistochemical analyses using a rat model previously revealed that stathmin-1 is exclusively localized in decidual cells, especially in the primary decidual zone surrounding the embryo with markedly more intense staining on day E9.5 than on day E7.5.…”

“…6 When stromal cells isolated from normal endometrial tissues were previously cultured and stimulated to decidualize by progesterone plus estrogen or cAMP, their total and phosphorylated stathmin levels decreased. Stathmin silencing in primary stromal cells using small interfering RNA before the cells are exposed to decidualizing agents also markedly suppresses decidualization, suggesting that stathmin may play a key role in decidualization.…”

Involvement of Stathmin in Proliferation and Differentiation of Immortalized Human Endometrial Stromal Cells

“…After 6 days of culture in culture medium containing 2% FBS, these cells exhibited a spindle-shaped morphology (Fig. 1A, control), which is similar to primary stromal cells [16]. To determine whether EtsT cells retain the characteristis of primary endometrial stromal cells, we examined their ability to decidualize upon stimulation with forskolin (an activator of protein kinase A) or the cAMP analog db-cAMP.…”

“…Endometrial stromal cells were prepared from the endometrial tissues of patients undergoing surgery or biopsies, as described previously [16]. Sample collection was conducted with the informed consent of the patients in accordance with the requirements of the clinical research ethics committee of the Tokyo Medical University Hospital.…”

“…The culture medium (10 µg protein) or cell lysate (3 µg protein) was then subjected to 15-20% gradient SDS-polyacrylamide gel electrophoresis (PAGE) for analysis of IGFBP-1, PRL, and stathmin expression as described previously [16]. We used a native PAGE system that separates stathmin phosphoisomers according to their charge differences to detect phosphorylated stathmin.…”