Expression profile of Let-7s in peripheral blood mononuclear cells of normal and severe preeclampsia pregnant women

https://doi.org/10.1016/j.yexmp.2019.104263Get rights and content

Abstract

Headings aim

We aimed to investigate if the let-7 s expression level in the serum of peripheral blood from pregnant women with severe pre-eclampsia and normal pregnant women is related to the incidence of severe pre-eclampsia.

Methods

Total RNA was extracted from collected peripheral blood mononuclear cells from 20 or over weeks pregnant women diagnosed with severe pre-eclampsia (age: 31.57 ± 4.94) and normal pregnant women (age: 29.75 ± 4.6) respectively, followed by real-time PCR to examine the expression of let-7 s. Correlation between let-7 s expression level and maternal age or body mass index of the normal pregnant women were also analyzed using SPSS21.0 software.

Results

Let-7a and let-7 g were significantly increased in pregnant women with severe pre-eclampsia by 4.67 fold and 2.37 fold respectively compared to the normal pregnant women, whereas there was no significant difference in let-7b and let-7i. Moreover, there was no correlation between maternal age or body mass index and the expression level of let-7a, let-7b, let-7 g, and let-7i.

Conclusions

In conclusion, let-7a and let-7 g were significantly increased in the PBMCs of severe pre-eclampsia women compared to normal controls. Moreover, their expression level was not correlated to the maternal age or body mass of patients. Our data indicated that let-7a and let-7 g may be considered as predictive markers for SPE.

Introduction

Preeclampsia (PE) usually occurs in pregnant women post 20 weeks gestation and is considered as a serious pregnancy problem for its incidence rate at 3–6% around worldwide.(Myatt and Roberts, 2015) Currently PE is considered as a syndrome, not a disease because of its complexity and multiple symptoms own to the involvement of several systems such as vascular, rental, coagulation, and liver.(Myatt and Roberts, 2015) Traditionally, PE is defined by hypertension (systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg) and proteinuria (protein >300 mg/24 h).(Mol et al., 2016; Lambert et al., 2014) With the increasing clinical data, PE could be diagnosed in the absence of proteinuria according to the new guideline of American College of Obstetricians and Gynecologists (ACOG) in 2013(American College of Obstetricians and Gynecologists, 2013). PE greatly affects maternal and perinatal morbidity and mortality for the lack of safe and effective therapeutic strategies, which accounts for >75,000 maternal deaths yearly in developing countries. Severe preeclampsia (SPE) is a more serious disorder of pregnancy, which causes more harms to pregnant women and fetal, even later in life.(Myatt and Roberts, 2015; Mol et al., 2016; Lambert et al., 2014; American College of Obstetricians and Gynecologists; Task Force on Hypertension in Pregnancy. Hypertension in pregnancy, 2013; Duley, 2009).

Increasing evidence demonstrates that pregnant women with higher maternal age, pre-gestational or gestational diabetes, chronic hypertension, and low socioeconomic condition have a higher incidence rate of PE.(Caritis et al., 1998; Kaaja, 2008) These factors could cause oxidative stress, inflammatory, abnormal invasion of trophoblast, shallow placental implantation, abnormal immune between maternal and fetus and aberrant gene expression to induce the pathogenesis of PE (Jauniaux et al., 2006; Roberts and Cooper, 2001; Redman and Sargent, 2003; Redman and Sargent, 2010). To understand the molecular mechanism of the pathogenesis of PE will not only enrich our basic knowledge in this area, and also provide potential therapeutic targets in clinical practice. Recently, studies focusing on the role of microRNAs (miRNAs) in human disease development become a hot research area. MiRNAs are a family of endogenous and small non-coding regulatory RNAs and have been reported to be involved in diverse biological processes including cell differentiation, apoptosis, and development through mRNA degradation or translational inhibition mechanism.(Bartel, 2004; Inui et al., 2010) To date, several studies have been conducted to investigate miRNAs' potential roles in the pathogenesis of PE, and aberrant expression of some miRNAs, such as miR-210, miR-181a, miR-15, miR-515, let-7, miR-223, and miR-126/126*, have been found in placental tissue or antenatal circulatory samples from PE patients, indicating miRNAs may play fundamental roles in a variety of physiological and pathological processes during the pathogenesis of PE.(Winger et al., 2015; Winger et al., 2014; Sheikh et al., 2016; Xu et al., 2014) Among of these discovered miRNAs, the let-7 family attracted our special attention because of their widely documented functions in biological processes such as cancer cell invasion and metastasis, embryonic development as well as cell proliferation, differentiation, and apoptosis.(Roush and Slack, 2008; Su et al., 2012; Boyerinas et al., 2010; Chen et al., 2013; Zhao and Popel, 2015; Wang et al., 2011; Hau et al., 2012) A number of studies reported that overexpression of let-7 suppressed the growth and invasion ability of cancer cells.(Hau et al., 2012; Qian et al., 2011; Yan et al., 2015; Kim et al., 2012; Lee et al., 2011; Wang et al., 2012) In addition, some evidence indicated that the behaviors of trophoblasts in cell proliferation and invasion are highly similar to that of cancer cells.(Soundararajan and Rao, 2004) Thus we hypothesized that let-7 may be involved in the process of trophoblast invasion into the maternal uterus which is a vital stage in the establishment of pregnancy.

Currently, fewer studies about Let-7 expression in PE have been reported. A study led by Noack et al.(Noack et al., 2011) presented the reduction of let-7b in the placenta of 5 pregnancy woman with PE compared to one normal pregnant woman. Yang and coworkers found that the expression of let-7a and let-7f-1 was increased in the serum of 4 pregnancy woman with PE compared to one normal pregnant woman, while deduction of let-7d and let-7 f. (Yang et al., 2011) Xu et al.(Xu et al., 2013) reported that lower expression of let-7i in placenta tissues was detected in pregnant women with SPE compared to normal pregnant women. Though studies discovered the aberrant expression of Let-7 member in PE patients, it is still hard to clarify their expression pattern because of limited participants and various sources of total RNA.

Whether Let-7 s could be used as predictive biomarkers in clinical diagnosis remains unclear, and more investigations are needed to obtain a consistent and robust let-7 s family expression pattern. In this presentation, we investigated the expression level of let-7a, let-7b, let-7 g, and let-7i in the serum of peripheral blood from 27 pregnant women with severe preeclampsia and 27 normal pregnant women. The purpose of this project is to explore the relationship between let-7 s level and SPE and to provide a scientific basis for clinical practice in the screening test and diagnosis for PE patients.

Section snippets

Guideline for participant recruitment

Recruited participants were selected from patients diagnosed with SPE or normal pregnancy after 20 weeks' gestation according to the diagnostic standards of Obstetrics (Xie X and Gou L, 8th version (Xie and Gou, 2013). All procedures were approved by the human research ethical committee of the Second Hospital of Jilin University. These patients routinely visited the obstetrics department of the second hospital of Jilin University from October 2015 to February 2016. Briefly, the inclusion

Results

Expression of let-7a, let-7b, let-7 g, and let-7i in peripheral white blood cells.

As Fig. 1.A shown, the expression of let-7a, let-7b, let-7 g, and let-7i was able to be detected using real-time PCR reaction method, and exhibited different expression level in normal pregnant women. Among these miRNAs, Let-7a has the highest expression level compared to that of let-7b, let-7 g, and let-7i, and the later three miRNAs have a similar expression level (Fig. 1.B). When comparing to the normal

Discussion

As mentioned above, PE affects maternal and perinatal morbidity and mortality in clinical practice for the lack of specific predictive markers and effective therapy. Early diagnosis and effective therapeutic strategies are in great need. A study led by Winger et al. indicated that Let-7 family could be used as predictive markers in early pregnancy stay by detecting circulating miRNA level.(Winger et al., 2015; Winger et al., 2014) In this study, we for the first time in the world investigated

Disclosure

The authors declare that there is no conflict of interest regarding the publication of this article.

Acknowledgments

This work was supported by the Provincial Natural Science Foundation of Jilin (Grant No. 20130206057SF to F-J Wu).

References (42)

  • American College of Obstetricians and Gynecologists; Task Force on Hypertension in Pregnancy

    Hypertension in pregnancy. Report of the American College of Obstetricians and Gynecologists' Task Force on hypertension in pregnancy

    Obstet. Gynecol.

    (2013)
  • B. Boyerinas et al.

    The role of let-7 in cell differentiation and cancer

    Endocr. Relat. Cancer

    (2010)
  • S. Caritis et al.

    Low-dose aspirin to prevent preeclampsia in women at high risk

    N. Engl. J. Med.

    (1998)
  • Z. Chen et al.

    Hypoxia-responsive miRNAs target argonaute 1 to promote angiogenesis

    J. Clin. Invest.

    (2013)
  • K. Duckitt et al.

    Risk factors for pre-eclampsia at antenatal booking: systematic review of controlled studies

    BMJ.

    (2005)
  • A. Hau et al.

    CD95 is part of a let-7/p53/miR-34 regulatory network

    PLoS One

    (2012)
  • M. Inui et al.

    MicroRNA control of signal transduction

    Nat. Rev. Mol. Cell Biol.

    (2010)
  • E. Jauniaux et al.

    Placental-related diseases of pregnancy: involvement of oxidative stress and implications in human evolution

    Hum. Reprod. Update

    (2006)
  • R. Kaaja

    Predictors and risk factors of pre-eclampsia

    Minerva Ginecol.

    (2008 Oct)
  • S.J. Kim et al.

    MicroRNA let-7a suppresses breast cancer cell migration and invasion through downregulation of CC chemokine receptor type 7

    Breast Cancer Res.

    (2012)
  • R. Kulshreshtha et al.

    A microRNA component of the hypoxic response

    Cell Death Differ.

    (2008)
  • 1

    Dandan Wang and Ning Liu contributed equally to this work.

    View full text