THBS1 regulates decidualization in URSA.

Inappropriate endometrial stromal decidualization has been implied as an important reason of many pregnancy-related complications, such as unexplained recurrent spontaneous abortion (URSA), preeclampsia and intrauterine growth restriction. Here, we observed that thrombospondin-1 (THBS1), an adhesive glycoprotein, was significantly downregulated in endometrial decidual cells from patients with URSA. The immortalized human endometrial stromal cell line T-HESC was used to investigate the possible THBS1-mediated regulation of decidualization. In vitro experiments found that the expression level of THBS1 increased with the normal decidualization process. Knockdown of THBS1 could decrease the expression levels of prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP1), two acknowledged human decidualization markers. Whereas, THBS1 overexpression could reverse these effects. The RNA sequencing results demonstrated that the extracellular regulated protein kinases (ERK) signaling pathway was potentially affected by the knockdown of THBS1. And we further confirmed that the regulation of THBS1 on decidualization was achieved through the ERK signaling pathway by the treatment of inhibitors. Moreover, knockdown of THBS1 in pregnant mice could impair decidualization and result in an increased fetus resorption rate. Altogether, our study demonstrated a crucial role of THBS1 in the pathophysiological process of URSA and provided some new insights into the research of pregnancy-related complications.