Expression And Function Of MiR-18b In Human Placentas From Pregnancies Complicated By Preeclampsia And Normal Pregnancies

Preeclampsia (PE) is a common pregnancy specific syndrome that ischaracterized by hypertension and proteinuria. It is agreed generally thatpreeclampsia results from the presence of a placenta and it is a leading cause ofmaternal and perinatal morbidity and death.[1]. PE is a common complication ofthe obstetrics while its mechanism is not clear. At present, most research showsthat the abnormal apoptosis and differentiation of the trophocyte lead to celldysfunction, and then the infiltrate of trophocyte is decreased and recasting ofthe spiral artery is not enough, at last resulted in pathological changes of the PE.So the dysfunction of trophocyte is an important reason for the PE. In recentyears, people find the microRNA (miRNA) has a important roles in regulatingthe process of cell biology, mainly involve in the proliferation, apoptosis,differentiation and other important biological processes. It has been reportedpreviously by our lab that many miRNAs (especially miR-18b) are expresseddifferently in the human placentas of patients with preeclampsia, compared withcontrol subjects[2]. So the miR-18b may play an important role in the pathogenesis of the PE. The miR-18b is a single noncoding RNA of20-24nucleotides. It can influence the stability and translation of the mRNA andregulate the expression of the mRNA. At present, its important role in regulatingthe cellular function has been found in many tissues, for example, a research hasshown that the miR-18b is over-expression in the colorectal cancer withoutmetastasis of the lymph node[3]. The result of predicting the target gene of thehsa-miR-18b through the software of the Targetscan and DIANA-microT showsthat the ERα is one of the target genes of the miR-18b. The ERα exerts itsbiological effects by combining the estrogen, and the research of the estrogenhas shown that it had important consequence on the implant of the embryonicstem cell and the invasion of the trophocyte. Yang yang of our lab found theexpression of the ERα is over-expression in the placentas of the PE patients bythe immunohistochemistry analysis[4]. So the further understanding of theexpression characteristics of the miRNA can help to understand the pathogenesisof the PE and provide the evidence for its treatment. This experiment isproposed to verify the chip result of our lab detect whether the expression of themiR-18b is abnormal in the placentas of the PE patients, and increase theexpression of the miR-18b in the HTR-8cells through the cell transfectiontechnology to detect the changes of the ERα expression, then verify therelationship between miR-18b and ERα.Objective1To investigate the expression of miR-18bin placental tissue of the PEpatients2To verify the relationship between miR-18b and ERα in HTR-8cellMethods1Collect the placental tissue of the PE patients and the normal pregnancy, then extract the total RNA in the placental tissue, at last investigate theexpression of the miR-18b in the placental tissue of the PE patients and thenormal pregnant women through the real-time PCR analysis2Transfect the pre-miR-18b mimics and miR-18b inhibitor molecule to HTR-8cell to increase and decrease the expression of the miR-18b, then investigate thechanges of the mRNA and protein of the ERα through the RT-PCR andwestern-blot technology, and verify whether there is a correlation in themiR-18b and estrogen receptorResultsThe result of Real-time PCR shows that compared to the normal pregnantwomen, the expression of miR-18b in the PE patients is decreased. It isconsistent with our early results in our lab,2After promoting and inhibiting the expression of the miR-18b in theHTR-8cell, the RT-PCR analysis which detecting the expression of ERα mRNAshows that there is no obvious difference between the over-expression group,inhibition group and blank control group.3After promoting and inhibiting expression of the miR-18b in the HTR-8cell, western-blot analysis which detecting the expression of ERα protein showsthat there is no obvious difference between the over-expression group, inhibitiongroup and blank control group.Conclusion1Compared to the normal pregnant women, the expression of miR-18b isdecreased in placental tissue of the PE patient, suggesting the miR-18b may leadto the occurrence and development of the PE2The miR-18b may has no significant role in regulating the expression ofthe ERα.