Manipulating Actin Dynamics Affects Human In Vitro Decidualization1

Abstract

The differentiation of uterine stromal fibroblasts into decidual cells is critical for establishing pregnancy. This process, called decidualization, requires the reorganization of the actin cytoskeleton, which mainly depends on actin dynamics and the phosphorylation status of the myosin light chain. We manipulated actin dynamics with jasplakinolide (100 nM) and latrunculin B (1 microM), both of which significantly inhibited the synthesis of decidualization markers induced by 6 days of treatment with embryo-mimicking stimulus interleukin 1beta (IL1B) and steroid hormones (SHs; 17beta-estradiol and medroxyprogesterone acetate) in the human uterine fibroblast (HuF) in vitro model. However, only jasplakinolide had long-lasting effects on the G-actin:F-actin ratio and prevented decidualization induced by the artificial stimulus cAMP (and SHs). Actin-binding protein cofilin mainly colocalized with G-actin in the nucleus as well as the cytoplasm. Only some spots of colocalization between cofilin and F-actin were detected in the cytoplasm. Brief extraction of cytosolic proteins from living cells revealed that in cells treated with IL1B or cAMP (and SHs) for 6 days, cofilin was mainly detected in the nucleus. The translocation of cofilin from cytosol to nucleus was also detected in HuFs treated for 12 days with SHs, IL1B and SHs, and cAMP and SHs. The same significant translocation was confirmed in primary baboon stromal uterine fibroblasts. We conclude that changes in actin dynamics, particularly the stabilization of F-actin, have a significant negative impact on decidualization, and the translocation of cofilin to the nucleus is a key feature of this process in the primate.

Proteomic analysis of porcine endometrial tissue during peri-implantation period reveals altered protein abundance

“…The regulation of these proteins is likely due to actin reorganization in uterine epithelial cells. Cofilin has an important role in decidualization and blastocyst implantation in humans [27,28]. Gelsolin is implicated in actin filament reorganization during cell locomotion [29], vesicle trafficking and in apoptosis [30].…”

“…F-actin levels were also altered during pregnancy with a decrease observed as pregnancy progressed to Day 12. Stabilization of F-actin has a significant negative impact on decidualization [27], and the breakdown of filamentous F-actin into monomers is required for the remodeling of epithelial cells for adhesion [35]. In addition, annexin A2 (ANXA2) levels decreased in the Day 12 compared to the Day 9 cycling endometrium.…”

Defective decidualization during and after severe preeclampsia reveals a possible maternal contribution to the etiology

“…Actin, which is concentrated in the cortex of decidual cells, most often in a filamentous form (i.e., F-actin), regulates the intracellular reorganization and resulting shape changes (18)(19)(20). Decidualization can also be viewed as a process whereby the cells acquire a secretory phenotype.…”

Kruppel-like factor 5 (KLF5) is critical for conferring uterine receptivity to implantation

“…Actin cytoskeleton reorganization is critical for normal decidualization (25). On day 4 before decidualization, actin is distributed around individual stromal cells without any obvious pattern (Fig.…”