Elsevier

Placenta

Volume 66, June 2018, Pages 47-56
Placenta

Effects of CXCL3 on migration, invasion, proliferation and tube formation of trophoblast cells

https://doi.org/10.1016/j.placenta.2018.05.004Get rights and content

Highlights

  • CXCL3 was expressed in trophoblasts of placenta and HTR-8/SVneo cells.

  • CXCR2, the receptor of CXCL3, was also presented in HTR-8/SVneo cells.

  • Trophoblasts' migration, invasion, proliferation, tube-formation were explored.

  • Above behaviors were bated by silencing CXCL3 and enhanced by upregulating CXCL3.

  • The apoptosis of trophoblasts was not affected by changing CXCL3 expression.

Abstract

CXCL3 was reportedly associated with the invasion and metastasis of various malignancies, the role of CXCL3, however, in preeclampsia has not been fully discussed. We previously found placental CXCL3 level in severe preeclampsia was significantly lower than that in healthy pregnancy and exogenous recombinant human CXCL3 protein was able to promote trophoblasts' migration and proliferation. The current study, therefore, is further to investigate effects of endogenous CXCL3 on migration, invasion, proliferation, tube formation and apoptosis of trophoblasts.

Immunofluorescence staining demonstrated that CXCL3 localized in both trophoblasts of placenta and HTR-8/SVneo cells. Moreover, data showed that migration, invasion, proliferation and tube-formation capability of HTR-8/SVneo cells transfected with siRNA-CXCL3 were suppressed by down-regulation of CXCL3, while those behaviors of HTR-8/SVneo cells transfected with pEZ-CXCL3 were enhanced by upregulation of CXCL3. Nevertheless, the apoptosis of HTR-8/SVneo cells was not affected by neither siRNA nor overexpression plasmid. The result suggests that CXCL3 is involved in migration, invasion, proliferation and tubule formation of trophoblasts and may play a key role in the pathogenesis of preeclampsia.

Introduction

Preeclampsia is a multi-system dysfunction severe pregnancy related disease featured by hypertension and proteinuria and affects 3%–7% of all pregnancies [1], which is still one of prime reasons for maternal and perinatal mortality and morbidity worldwide. Exact pathophysiology of preeclampsia is still unknown, whereas abnormal placental development may point out the reasons why [2]. During early normal placentation, partial cytotrophoblasts detached from the villous become extravillous trophoblasts (EVTs) that subsequently generate both interstitial EVTs invading into the maternal decidua even superficial myometrium and endovascular EVTs remodeling uterine spiral arteries, resulting in transforming the high-resistance, low-capacity uterine spiral arteries into the high-capacity, low-resistance blood circulation beneficial to fetal development [3]. This process is controlled complicatedly by the interaction of chemokines, growth factors and transcription factors [4]. Recently, the two-stage model hypothesis puts the origin of clinical symptoms of preeclampsia down to the inadequate EVTs invasion and the consequent insufficient remodeling of spiral arteries with it, which further lead to generalized maternal endothelial dysfunction and inappropriate maternal inflammatory response, but the mechanism underlying this hypothesis is still unknown [5,6]. Yet studies have shown that abnormal immune cells and cytokine signaling arisen from excessively maternal immune and inflammatory responses are involve in these cascade amplification reactions and implicated in the migration, invasion and proliferation of trophoblasts [7,8]. In addition, chemokine exists extensively in the maternal-fetal interface and associates with the regulation of trophoblasts, which may play an inevitable key role in the immune mechanism of preeclampsia [9,10].

Chemokine is a bioactive protein superfamily with low molecular weight classified into four subgroups (CC or β, CXC or α, C and CX3C), which participates in various pathophysiological processes. CXCL3, encoded by the human GRO gene and also known as growth-related oncogene γ (GRO-γ), is a member of ELR + CXC group subdivided from CXC family [11]. Reportedly, it plays a crucial role in chemotactic process [12], vascularization [13], tumorigenesis [14], cell differentiation [15], and cell invasion and migration [16,17] by binding with CXCR1 and CXCR2 expressed in diverse cells like leukocytes [18], tumor cells [19], smooth muscle cells [20], decidual and villous cells [21] as well as human vascular endothelial cells [22]. In recent years, CXCL3 is widely attracted for the findings in oncology that it up-regulates in aggressive breast cancer [23] and prostate cancer [16] and enhances the metastasis of cholangiocarcinoma [24] and melanoma [25]. Moreover, CXCL3 also connects with the migration of such non-tumor cell as neuron precursor cells and airway smooth muscle cells [20,26].

Gestational trophoblast is known as the pseudo-tumor cell. Admittedly, analogical invasive properties exist between EVTs and malignant cells. Nevertheless, the role of CXCL3 in gestational trophoblasts remains unclear. Similarities between maternal-fetal interface and tumor microenvironment and the striking likeness between EVTs and cancer cells in their biological behavior [27,28] may be conducive to give us enlightenment upon the role of CXCL3 in the pathogenesis of preeclampsia. Our previous research has shown that placental expression of CXCL3 in severe preeclampsia was significantly decreased and exogenous CXCL3 was able to promote migration and proliferation of trophoblasts [29]. The role of endogenous CXCL3, however, in the pathogenesis of preeclampsia remains unclear up to now. Therefore, the present work is to explore effects of endogenous CXCL3 on migration, invasion, proliferation, tube formation and apoptosis of trophoblasts, which may make a certain contributions to reveal the pathogenesis of preeclampsia.

Section snippets

Tissue sections, cell climbing slides and immunofluorescence staining

Placenta tissue was collected promptly from normal full-term pregnant women after elective cesarean delivery for such obstetrical factors as the presence of placenta previa and cephalopelvic disproportion as described previously [30]. Informed consent was obtained from all participants, and the research was approved by the ethics committee of West China Second University Hospital of Sichuan University.

Tissue blocks of 1.0 cm3, avoiding vessels, calcification or infarction, were taken from the

Statistical analysis

Every experiment repeated in three times. Data were analyzed by SPSS 23.0 and displayed as mean ± standard error of mean (SEM). One-way analysis of variance test was utilized to compare statistical difference more than two groups, while difference between two groups was analyzed by Student's t-test. A p value of <0.05 was supposed to be statistical significance.

Expression of CXCL3 in trophoblasts of the human placenta

As shown in Fig. 1, CXCL3 (Fig. 1B, green) was strongly expressed in trophoblasts labeled by anti-CK7 antibody (Fig. 1A, red) in placental tissue sections with the immunolocalization method. CK7 and CXCL3 appeared strong co-localization in trophoblasts (Fig. 1D). Nuclei were stained as blue with DAPI (Fig. 1C).

Expression of CXCL3 in HTR-8/SVneo cells

Pictures in Fig. 2 showed that CXCL3 (Fig. 2A, green) was presented in HTR-8/Svneo cells detected by immunofluorescence staining (Fig. 2C). Nuclei were dyed as blue with DAPI (Fig. 2B and

Discussion

In the first trimester, invasive phenotype EVTs play a pivotal function in the establishment of maternal-fetal circulation [4]. Currently, the role of shallow EVTs invasion and subsequently abnormal remodeling of spiral arteries was emphasized in the pathogenesis of preeclampsia [5], which was regulated by various immune and inflammatory cells and related cytokine signaling [8,9].

Reportedly, CXCL3 is associated with diverse pathophysiological processes and correlated with the development and

Funding

This work was supported by the National Natural Science Foundation of China (No. 81571465) and Key Research and Development Program of Sichuan Science and Technology Agency (NO. 2017FZ0067).

Conflicts of interest

No competing interests exist.

Author contributions

Conceived and designed the experiments: Rong Zhou. Executed the experiments: Hui Wang and Li Dai. Analyzed the data: Hui Wang, Tao Wang, Wen Cao, Lei Ye, Linbo Gao. Contributed reagents/materials/analysis tools: Li Dai and Bin Zhou. Wrote the paper: Hui Wang, Tao Wang, Rong Zhou.

References (36)

  • D. Wu et al.

    CXCR2 is decreased in preeclamptic placentas and promotes human trophoblast invasion through the Akt signaling pathway

    Placenta

    (2016)
  • N. Al-Jameil et al.

    A brief overview of preeclampsia

    J. Clin. Med. Res.

    (2014)
  • J.L. James et al.

    Cytotrophoblast differentiation in the first trimester of pregnancy: evidence for separate progenitors of extravillous trophoblasts and syncytiotrophoblast

    Reproduction

    (2005)
  • B. Alasztics et al.

    The pathophysiology of preeclampsia in view of the two-stage model

    Orv. Hetil.

    (2012)
  • J. Dietl

    The pathogenesis of pre-eclampsia: new aspects

    J. Perinat. Med.

    (2000)
  • E. Laresgoiti-Servitje

    A leading role for the immune system in the pathophysiology of preeclampsia

    J. Leukoc. Biol.

    (2013)
  • N. Gomez-Lopez et al.

    Invasion of the leukocytes into the fetal-maternal interface during pregnancy

    J. Leukoc. Biol.

    (2010)
  • N.J. Hannan et al.

    The chemokines, CX3CL1, CCL14, and CCL4, promote human trophoblast migration at the feto-maternal interface

    Biol. Reprod.

    (2006)
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    Both authors contributed equally to this work.

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