Human placental single-cell transcriptomic atlas in physiological and pathological condition

• Grant number: 24/01716-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2024
• End date: December 31, 2024
• Field of knowledge: Health Sciences - Medicine - Maternal and Child Health
• Principal Investigator: Andre de Souza Mecawi
• Grantee: Rafaela Giraçol da Cruz
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• Associated research grant: 19/27581-0 - Control of vasopressin secretion in pregnancy and its implications in pathophysiology of Preeclampsia, AP.JP

Abstract

Pregnancy is a period of intense changes in the maternal body, with the placenta being the main component of the maternal-fetal interface. Gestational success and the growth of the fetoplacental unit depend directly on the proper execution of its functions, such as the secretion of hormones that drive the necessary metabolic and physiological adaptations in the maternal organism. Functional alterations in this organ are associated with various gestational complications, such as preeclampsia, gestational diabetes, and systemic infections. To identify and understand these conditions at the cellular and molecular levels, several studies have emerged in recent years conducting single-cell RNA sequencing of this organ under different conditions. This technology allows, through the transcriptome, the analysis of cellular heterogeneity, identification of cell types, prediction of cellular communication, and evaluation of gene transcription alterations. This project proposes the creation of a transcriptomic cellular atlas of the human placenta, integrating data from studies that have previously conducted sequencing of this organ under different conditions, in order to predict pathways of placental cell communication, discover new genes and molecular and cellular mechanisms involved in its function in the healthy state, and describe alterations in gene expression profiles and their conservation among various pathological states. In addition, this approach will provide greater statistical power, enabling the identification of new molecular targets (genes) potentially enriched in rare cell types that would not be discovered in isolated studies. For the present study, 17 articles (published between 2017 and 2023) were selected from different libraries and scientific journals based on the following criteria: presenting scRNA-Seq/snRNA-Seq of placenta or human maternal-fetal interface with published and freely available data for use. Among these, articles were selected that included sequencing of placentas from healthy pregnancies, as well as pregnancies with different complications and conditions such as specific pathologies, advanced maternal age, and different gestational periods. The acquired data in FASTA formats will be aligned and analyzed using the CellRanger 7.1 software according to the reference genome (GRCh38). Then, the data will be integrated and bench effects normalized using the Harmony, CCA, RPCA, and scVI tools methods using the Seurat 5.0 package (to choose the best integration method). Cell types will be identified based on canonical marker genes. The Wilcoxon test will be used to determine genes enriched in cell types and differentially expressed in control and pathological conditions; Spearman correlation for gene associations discovery; ClusterProfiler (v.4.6.2) for analysis of enriched gene pathways; the IUPHAR catalog to classify the pharmacological classes of genes; and CellChat for inference of cellular communication patterns. Expected results include the creation of a comprehensive cellular transcriptomic atlas, providing insights into placental metabolism, cellular communication, etiology of gestational diseases, and cellular response under different conditions, contributing to the understanding of complex cellular interactions in the placenta and paving the way for future research on the prevention and treatment of gestational complications.