Objective:To evaluate the effects of mesoderm-specific transcript(MEST)on cell migration and invasion in the human trophoblast cells and its roles in preeclampsia. Methods:Immunohistochemistry and Western blot were used to determine the expression of MEST and DNA methyltransferases(DNMTs)in normal and preeclampsia(PE)placental tissues

and to detect the MEST promoter methylation level. HTR8/SVneo cells were treated by hypoxia/ reoxygenation(H/R)or MEST si RNA before detecting the MEST

hypoxia-inducible factor 1α(HIF1α)protein expression and the cell proliferation

migration and invasion ability

respectively. Results:MEST protein expressions were significantly decreased(4.524±0.586

2.640±0.334)and its gene promoters were hypermethylated in the PE placental tissues. After H/R treatment

the MEST expressions were downregulated(4.856±0.169

2.205±0.318)while HIF1αwere upregulated(3.692±0.441

7.091±0.698)(P<0.05). The cell proliferation was not affected by si RNA of MEST(0.170±0.010

0.158±0.010)(P >0.05)

while the migration and invasion rate of HTR-8/SVneo cells were significantly decreased(1.057 ±0.061

0.551±0.029)(1.113±0.087

0.477±0.034)(P<0.05). Conclusion:MEST/PEG1 DNA methylation represses trophoblast migration and invasion

a possible pathological mechanism of preeclampsia.