Growth differentiation factor-8 promotes human extravillous trophoblast cell invasion by increasing ANGPTL4 expression

Abstract

Introduction: Proper regulation of extravillous trophoblast (EVT) cell invasion is critical for normal placental development and function. Angiopoietin-like 4 (ANGPTL4), a multifunctional protein, has previously been implicated in promoting EVT cell invasion. Growth differentiation factor-8 (GDF-8), a member of the transforming growth factor-β (TGF-β) superfamily, also stimulates EVT cell invasion. However, it remains unclear whether GDF-8 regulates ANGPTL4 expression and how this regulation contributes to the invasive behavior of human EVT cells. This study aims to explore the role of ANGPTL4 in GDF-8-induced EVT cell invasion and to uncover the underlying molecular mechanisms.

Methods: The immortalized EVT cell line HTR-8/SVneo and primary human EVT cells were used as in vitro models. The effects of GDF-8 on ANGPTL4 expression and the underlying signaling mechanisms were investigated using RT-qPCR and Western blot analysis. Cell viability was assessed using the MTT assay, and cell invasiveness was examined using a Matrigel-coated transwell invasion assay.

Results: Our results demonstrated that GDF-8 increased ANGPTL4 expression. Mechanistically, we found that activin receptor-like kinases 4 and 5 (ALK4 and ALK5) were required for GDF-8-mediated upregulation of ANGPTL4. Additionally, both SMAD2 and SMAD3 were involved in this regulatory pathway. We further showed that GDF-8 treatment promoted cell invasion without affecting cell viability. The pro-invasive effect of GDF-8 was attenuated by ANGPTL4 knockdown, whereas ANGPTL4 overexpression alone enhanced cell invasiveness.

Discussion: This study reveals a novel role for GDF-8 in regulating ANGPTL4 expression and EVT cell invasion, offering new insights into placental development and potential implications for pregnancy-related disorders.

Keywords: ANGPTL4; EVT; GDF-8; Invasion; SMAD.