The chemokine CXCL6 restricts human trophoblast cell migration and invasion by suppressing MMP-2 activity in the first trimester.

Can the chemokine CXCL6 affect trophoblast cell migration and invasion in human first-trimester placenta? Chemokine CXCL6 inhibits trophoblast cell migration and invasion by suppressing matrix metalloproteinase (MMP)-2 activity in human first-trimester placenta. Several chemokines including CXCL8, CXCL12, CXCL14, CXCL16, CX3CL1, CCL14 and CCL4 can promote or inhibit trophoblast cell migration and invasion in human first-trimester placenta. We used the trophoblast cell line HTR8/SVneo cells, primary trophoblast cells and villi explants to investigate the effect of rhCXCL6 on trophoblast cell migration and invasion. First, the CXCL6 RNA transcript level was detected in HTR8/SVneo cells derived from human first-trimester, second-trimester and third-trimester placenta by RT-PCR. Protein expression of CXCL6 and its receptors was tested in first-trimester placenta by immunohistochemistry. Secreted CXCL6 protein was detected in HTR8/SVneo cell supernatants by enzyme-linked immunosorbent assay. Secondly, the effect of rhCXCL6 on HTR8/SVneo cell proliferation was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Thirdly, the effect of rhCXCL6 on cell migration and invasion of HTR8/SVneo cells, primary trophoblast cells and villi explants was tested by transwell migration and invasion assays, respectively. Last, MMP-2 and MMP-9 activity in the supernatants of HTR8/SVneo and primary trophoblast cells treated by rhCXCL6 in the invasion assay was assessed by gelatin zymography. Abundance of the CXCL6 RNA transcript increased with pregnancy development. CXCL6 and its receptor were expressed in several cells at the human maternal-fetal interface. RhCXCL6 inhibited trophoblast cell migration and invasion by suppressing MMP-2 activity. These experiments are only in vitro. According to the literature, CXCL6 could promote tumour cell migration and invasion by accelerating MMP-9 activity. However, CXCL6 inhibited trophoblast cell migration and invasion by suppressing MMP-2 activity in human first-trimester interface. These data suggest that strict regulation of CXCL6 is required for normal migration and invasion of cells, such as those involved at the maternal-fetal interface.

Zhang H ，Hou L ，Li CM ，Zhang WY ... -  《-》

Expression of Gadd45α in human early placenta and its role in trophoblast invasion.

Well-controlled trophoblast migration and invasion at the maternal-foetal interface are crucial events for normal placentation and successful pregnancy. Growing evidence has revealed that growth arrest and DNA damage-inducible 45 alpha (Gadd45α) participates in tumour migration and invasion as a tumour suppressor. However, the expression and function of Gadd45α in trophoblasts is unknown. This study aimed to determine the Gadd45α expression and function in the human first trimester placenta and identify the underlying mechanisms. The expression of Gadd45α in human first trimester placenta was determined using immunohistochemistry. HTR8/SVneo cell line was used to investigate the effects of Gadd45α on proliferation, apoptosis, migration/invasion, matrix metalloproteinase (MMP)2/9 activities, and tissue inhibitor of metalloproteinase (TIMP)1/2 expression using cell proliferation assays, flow cytometric analysis, transwell migration/invasion assays, gelatin gel zymography, and western blotting, respectively. Moreover, a placental villous explant model was employed to verify its functions in placentation. Gadd45α was strongly expressed in syncytiotrophoblasts and trophoblast columns of human placental villi, extravillous trophoblast cells and glandular epithelium within the maternal decidua. Gadd45α knockdown significantly promoted migration and invasion of HTR8/SVneo cells, whereas it did not affect cell proliferation or apoptosis. Silencing Gadd45α also enhanced trophoblast outgrowth and migration in placental explants. These effects were related to increased activities of MMP2/9 and the decreased expression of TIMP1/2. Gadd45α may be involved in human trophoblast migration and invasion and may function as an important negative regulator at the foetal-maternal interface during early pregnancy by directly or indirectly regulating MMP2/9 activities.

Liu X ，Mu H ，Luo X ，Xiao X ，Ding Y ，Yin N ，Deng Q ，Qi H ... -  《-》

The cytokine gene CXCL14 restricts human trophoblast cell invasion by suppressing gelatinase activity.

Well-controlled trophoblast invasion into uterine decidua is a critical process for the normal development of placenta, which is tightly regulated by various factors produced within the trophoblast-endometrial microenvironment. CXCL14 is involved in tumor growth and metastasis, and its expression in placenta is temporally regulated during pregnancy. However, the role of CXCL14 in trophoblast function during human pregnancy is not clear. In this study, by using RT-PCR through human pregnancy, we found that CXCL14 was selectively expressed at early but not late pregnancy. Immunostaining revealed that CXCL14 proteins were strongly expressed in villous cytotrophoblasts and moderately in decidualized stromal cells but very weakly in syncytiotrophoblasts and extravillous trophoblasts. The effect of CXCL14 on trophoblast invasion were examined by using human villous explants cultured on Matrigel and further proved by invasion and migration assay of primary trophoblast cells and trophoblast cell line HTR-8/SVneo. Our data showed that CXCL14 significantly inhibited outgrowth of villous explant in vitro; this effect is due to suppression of trophoblast invasion and migration through regulating matrix metalloproteinases activities, whereas the trophoblast proliferation was not affected. Moreover, because a receptor for CXCL14 has not been identified, we performed further cell-specific CXCL14 binding activities with regard to different cell types within the maternal-fetal interface. Our data revealed that CXCL14 could specifically bind to trophoblast cells but not decidual cells from the maternal-fetal interface. These results suggest that CXCL14 plays an important role in regulating trophoblast invasion through an autocrine/paracrine manner during early pregnancy.

Kuang H ，Chen Q ，Zhang Y ，Zhang L ，Peng H ，Ning L ，Cao Y ，Duan E ... -  《-》

Control of extravillous trophoblast function by the eotaxins CCL11, CCL24 and CCL26.

Chau SE ，Murthi P ，Wong MH ，Whitley GS ，Brennecke SP ，Keogh RJ ... -  《-》

Chemokine CXCL16, a scavenger receptor, induces proliferation and invasion of first-trimester human trophoblast cells in an autocrine manner.

Huang Y ，Zhu XY ，Du MR ，Wu X ，Wang MY ，Li DJ ... -  《HUMAN REPRODUCTION》