Elsevier

Placenta

Volume 44, August 2016, Pages 80-82
Placenta

Short communication
Punicalagin promotes human villous trophoblast differentiation

https://doi.org/10.1016/j.placenta.2016.06.007Get rights and content

Highlights

  • Cultured primary human trophoblasts showed reduced expression of E-cadherin.

  • Silencing of GCM1 decreased expression of β -hCG in the primary cultures of trophoblasts.

  • Punicalagin reduced expression of E-cadherin and increased expression of syncytin 1, β-hCG and GCM1in trophoblasts.

Abstract

Poor differentiation of trophoblasts is associated with placental dysfunction, predisposing women to multiple pregnancy disorders. Punicalagin, a prominent ellagitannin in pomegranate juice has been shown to exert anti-apoptosis and anti-oxidative effects in human trophoblasts. We hypothesized that punicalagin modulates trophoblast differentiation. We found that punicalagin-treated primary trophoblast showed reduced E-cadherin, higher Syncytin 1, more β−hCG, and increased GCM1, an upstream regulator of β−hCG. Punicalagin exposure of villous explants enhanced the number of cytotrophoblasts expressing the proliferation marker Ki67. We conclude that punicalagin enhances trophoblast differentiation and speculate that punicalagin might be used therapeutically in pregnancies at risk for placental dysfunction.

Introduction

Placental villi are covered with a multinucleated mass of syncytium. Cytotrophoblasts subjacent to the syncytium proliferate, differentiate, and fuse to replenish syncytiotrophoblast throughout pregnancy. Villi are bathed in maternal blood from 8 to 10 weeks’ gestation, making this epithelial bi-layer susceptible to mechanical, oxidative, nitrative, and toxic stressors [1]. Injury to trophoblast reduces the capacity of the human placenta to perform key functions critical for fetal development. No therapy with an acceptable risk-benefit profile has been identified to optimize villous trophoblast activity in women at risk for placental dysfunction.

We and others discovered punicalagin, a prominent polyphenol within pomegranate juice, protects trophoblasts and embryos from oxidative stress, through enhanced autophagy, diminished apoptosis, and differential gene expression [2], [3], [4], [5], [6]. Resveratrol and curcumin are other polyphenols that were also reported to benefit pregnancy in both human and animal models [7], [8]. They also show differentiation-inducing effect in other systems, such as in cancer and neuron cells [9], [10]. We now test the hypothesis that punicalagin modulates differentiation of trophoblasts.

Section snippets

Methods

This study was approved by the IRB of Washington University School of Medicine in St Louis, MO. Primary human trophoblasts (PHTs) and villous explants were derived from placentas of uncomplicated singleton pregnancies delivered by scheduled cesarean section without labor at 39 weeks’ gestation, as described [3]. PHTs or explants were cultured in phenol red-free DMEM (Sigma, St. Louis, MO) with punicalagin (33.8 μM; Sigma) or vehicle control (7.5 mM glucose in water) at 37 °C under 20%

Results and discussion

Under normal culture conditions, cultured primary human cytotrophoblasts will differentiate and fuse to form syncytiotrophoblasts. We first examined E-cadherin, which marks the borders between cytotrophoblasts and decreases in expression after differentiation and cell-cell fusion [14]. We found that levels of E-cadherin decreased during culture. Notably, expression was significantly lower than controls in punicalagin-treated cells at 72 h, consistent with enhanced syncytial formation (Fig. 1A).

Disclosure

None of the authors have a conflict of interest.

Acknowledgments

This work was supported by the BJH Foundation, the Department of Obstetrics and Gynecology at Washington University School of Medicine, St Louis, MO, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)—Science Without Borders (200356/2014-3 to MLC), and by São Paulo Research Foundation - (FAPESP - 2014/01925-0 to MLC). We thank Dr. Deborah J. Frank for critical reading of the manuscript.

Cited by (4)

  • Transposable elements, placental development, and oocyte activation: Cellular stress and AMPK links jumping genes with the creation of human life

    2018, Medical Hypotheses
    Citation Excerpt :

    Both AMPKα1 and -α2 isoforms and the upstream AMPK kinase LKB1 have been found in human placentas and cellular stress was shown to induce phosphorylation and activation of AMPK in term placentas from normotensive women [94,95]. Moreover, punicalagin, a compound derived from pomegranate, activates AMPK, increases the expression of syncytin-1 and GCM1, and induces human trophoblast differentiation [96,97]. Treatment of CTB cells derived from human placenta with troglitazone, a PPARγ agonist that activates AMPK, also induced cell fusion and significantly increased syncytin-1 and hCG [98,99].

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