Trophoblasts-derived chemokine CCL24 promotes the proliferation, growth and apoptosis of decidual stromal cells in human early pregnancy.

Chemokine CCL24 is the second member of eotaxins, a group of eosinophils’ selectively chemoattractants. Via binding to its only receptor CCR3, CCL24 mainly mediates atopic disorders, parasitic infections and systemic diseases. It is well-known that CCR3 is expressed at the maternal-fetal interface; nevertheless whether CCL24 is located there and which role CCL24/CCR3 axis played is unclear. In this article, we assessed the expression of CCL24 and CCR3 in decidual stromal cells (DSCs) and trophoblasts, investigated the effects of DSCs-trophoblasts contact and pregnancy-associated hormones on the expression of CCR3 by DSCs, and last examined the role of trophoblasts-derived CCL24 on the proliferation, cell numbers and apoptosis of DSCs in vitro. We found that trophoblasts secrete chemokine CCL24, whereas DSCs express receptor CCR3. DSCs and trophoblasts co-culture had an raised level of CCL24 in culture supernatants, and the expression of CCR3 on DSCs was also obviously improved. Estrogen, progesterone and hCG up-regulated the expression of CCR3 on DSCs at appropriate concentration. CCL24 increased the proliferation and apoptosis of DSCs, whereas on the whole it promoted the number of DSCs. Thus, we conclude that by secreting CCL24 trophoblasts could promote the growth of DSCs; pregnancy associated environments such as DSCs-trophoblasts contact and hormones increased local CCL24/CCR3, which means a beneficial factor for the process of decidualization in human early pregnancy.