Deciphering Maternal-Fetal Crosstalk in the Human Placenta During Parturition Using Single-Cell RNA-Sequencing

Labor is a complex physiological process requiring a well-orchestrated dialogue between the mother and fetus. However, the cellular contributions and communications that facilitate maternal-fetal crosstalk in labor have not been fully elucidated. In this latest version (#5), scRNA-seq was applied to decipher maternal-fetal signaling in the human placenta and chorioamniotic membranes during term labor. Samples were obtained from women who underwent spontaneous labor (n = 24) or who were delivered in the absence of spontaneous labor (n = 18) at term. Samples from previous versions (#1-3) of this study include the placental villous tree, basal plate, and chorioamniotic membranes of women across a range of pregnancy physiologic and pathologic conditions, including the processes of labor (term labor and preterm labor), and COVID-19 (version #3). Version #4 includes samples from the human myometrium during spontaneous term labor.]]>
In version 1: For the scRNA-seq study of the placenta, in which we explored the physiologic (term labor) and pathologic (preterm labor) processes of parturition, labor was defined by the presence of regular uterine contractions at a frequency of at least two contractions every 10 min with cervical changes resulting in delivery. Women with preterm labor delivered between 33-35 weeks of gestation whereas those with term labor delivered between 38-40 weeks of gestation. In version 2: For the scRNA-seq and snRNA-seq study of the placenta, in which we explored the expression of the canonical receptors for SARS-CoV-2, samples were collected from women who delivered in the second and third trimesters. No stringent exclusion criteria were utilized since this was an exploratory study. In version 3: For the scRNA-seq study of the placenta, in which we explored the immune responses triggered by SARS-CoV-2 infection, samples were collected from women who tested positive for SARS-CoV-2 (most of them were asymptomatic) and gestational age-matched controls. All women delivered a term neonate. Only singleton pregnancies were included. In version 4: For the scRNA-seq study of the myometrium, in which we explored the physiologic process of labor, uterine samples from women who underwent cesarean section were collected at term (≥ 37 weeks of gestation) and were divided into the following groups: term not in labor (N = 13) and term in spontaneous labor (N = 11).In version 5: Samples were obtained from women who underwent spontaneous labor (n = 24) or who were delivered in the absence of spontaneous labor (n = 18) at term and comprised a biopsy of the chorioamniotic membranes (CAM, comprising the amnion, chorion, and decidua parietalis) as well as a biopsy that included basal plate (decidua basalis) and placental villi (BPPV). The collection and use of human materials for research purposes were approved by the Institutional Review Board of the Wayne State University School of Medicine. All participating women provided written informed consent prior to sample collection. ]]>
Version 1 focused on using scRNA-seq to profile the placental villous tree, basal plate, and chorioamniotic membranes of women across a range of pregnancy conditions with a focus on labor both at term and preterm. Version 2 focused on the expression of the canonical receptors for SARS-CoV-2 in scRNA-seq data. We have performed scRNA-seq of the human placenta in the second trimester to investigate the expression of the canonical receptors for SARS-CoV-2 in both second and third (first study including term and preterm placentas) trimesters. Furthermore, we performed single-nuclear RNA-seq (snRNA-seq) in several cases from third trimester-derived placentas to better observe the expression of the canonical receptors for SARS-CoV-2 in the syncytiotrophoblast cells. Version 3 focused on investigating the local immune responses in the placental tissues, including the chorioamniotic membranes, triggered by SARS-CoV-2 infection during pregnancy. We performed scRNA-seq analysis of the placenta of women who tested positive for SARS-CoV-2 during pregnancy and delivered a term neonate. Most of the women were asymptomatic. Controls included women who delivered a term neonate but SARS-CoV-2 infection was negative as evidenced by undetectable IgG and IgM levels in the systemic circulation. Version 4 focused on establishing a single-cell atlas of the myometrium and the unraveled cell type-specific transcriptomic activity modulated during labor. Version 5 focused on deciphering the maternal-fetal signaling in the human placenta and chorioamniotic membranes during term labor.]]>