Maternal-fetal interfaces transcriptome changes associated with placental insufficiency and a novel gene therapy intervention

Abstract

The etiology of fetal growth restriction (FGR) is multifactorial, although many cases often involve placental insufficiency. Placental insufficiency is associated with inadequate trophoblast invasion, resulting in high resistance to blood flow, decreased availability of nutrients, and increased hypoxia. We have developed a nonviral, polymer-based nanoparticle that facilitates delivery and transient gene expression of human insulin-like 1 growth factor (hIGF1) in placental trophoblast for the treatment of placenta insufficiency and FGR. Using the established guinea pig maternal nutrient restriction (MNR) model of placental insufficiency and FGR, the aim of the study was to identify novel pathways in the subplacenta/decidua that provide insight into the underlying mechanism driving placental insufficiency and may be corrected with hIGF1 nanoparticle treatment. Pregnant guinea pigs underwent ultrasound-guided sham or hIGF1 nanoparticle treatment at midpregnancy, and subplacenta/decidua tissue was collected 5 days later. Transcriptome analysis was performed using RNA Sequencing on the Illumina platform. The MNR subplacenta/decidua demonstrated fewer maternal spiral arteries lined by trophoblast, shallower trophoblast invasion, and downregulation of genelists involved in the regulation of cell migration. hIGF1 nanoparticle treatment resulted in marked changes to transporter activity in the MNR + hIGF1 subplacenta/decidua when compared with sham MNR. Under normal growth conditions however, hIGF1 nanoparticle treatment decreased genelists enriched for kinase signaling pathways and increased genelists enriched for proteolysis, indicative of homeostasis. Overall, this study identified changes to the subplacenta/decidua transcriptome that likely result in inadequate trophoblast invasion and increases our understanding of pathways that hIGF1 nanoparticle treatment acts on to restore or maintain appropriate placenta function.NEW & NOTEWORTHY Placental insufficiency at midpregnancy, established through moderate maternal nutrient restriction, is characterized with fewer maternal spiral arteries lined by trophoblast, shallower trophoblast invasion, and downregulation of genelists involved in the regulation of cell migration. Treatment of placenta insufficiency with a hIGF1 nanoparticle results in marked changes to transporter activity and increases our mechanistic understanding of how therapies designed to improve fetal growth may impact the placenta.

Keywords: IGF1; fetal growth restriction; nanoparticle; placental insufficiency; trophoblast invasion.

Graphical abstract

Figure 1.

Representative serial sections of guinea pig subplacenta/decidua stained for cytokeratin (trophoblast cells) and smooth muscle actin (SMA: endothelial cells), as well as depth of trophoblast invasion. A: in Control and Control placentas treated with hIGF1 nanoparticle (Control + hIGF1), there were more vessels lined with trophoblast (Asterix) compared with uninvaded vessels represented by smooth muscle actin lined vessels (hashtag). In maternal nutrient restricted (MNR) and MNR placentas treated with hIGF1 nanoparticle (MNR + hIGF1), there was clear trophoblast invasion; however, the number of vessels lined with trophoblast and not lined with SMA-positive endothelial cells was diminished. B: irrespective of hIGF1 nanoparticle treatment, the depth of vessels invaded with trophoblast was reduced with MNR compared with Control. n = 4–5 placentas stained/group. Data are estimated marginal mean ± 95% confidence interval. Dashed line marks the edge of the subplacenta trophoblast cell columns. hIGF1, human insulin-like 1 growth factor.

Figure 2.

Principal component analysis (PCA) on normalized expression data between subplacenta/decidua tissue from female and male fetuses. The normalized gene expression was not different enough between subplacenta/decidua tissue of female and male fetuses to separate into distinct groups. n = 12 females and 11 males.

Figure 3.

The number of differentially expressed genes in the guinea pig subplacenta/decidua was modified by maternal nutrient restriction (MNR) and/or hIGF1 nanoparticle treatment. Compared with Control, hIGF1 nanoparticle treatment (Control + hIGF1) resulted in 2,498 genes being downregulated and 1,406 genes upregulated. MNR resulted in 258 genes being downregulated and 208 genes upregulated when compared with Control. In MNR subplacenta/decidua, hIGF1 nanoparticle treatment (MNR + hIGF1) resulted in 117 downregulated genes and 130 upregulated genes when compared with sham-treated MNR. n = 5 Control, 3 Control + hIGF1, 6 MNR, and 8 MNR + hIGF1 subplacenta/decidua samples. hIGF1, human insulin-like 1 growth factor.