Stromal Heterogeneity in the Human Proliferative Endometrium-A Single-Cell RNA Sequencing Study.

Suzanna Queckbörner,Lindsay C Davies,Kristina Gemzell-Danielsson,Nageswara Rao Boggavarapu,Carolina Von Grothusen,Roy Mathew Francis

doi:10.3390/jpm11060448

Abstract

The endometrium undergoes regular regeneration and stromal proliferation as part of the normal menstrual cycle. To better understand cellular interactions driving the mechanisms in endometrial regeneration we employed single-cell RNA sequencing. Endometrial biopsies were obtained during the proliferative phase of the menstrual cycle from healthy fertile women and processed to single-cell suspensions which were submitted for sequencing. In addition to known endometrial cell types, bioinformatic analysis revealed multiple stromal populations suggestive of specific stromal niches with the ability to control inflammation and extracellular matrix composition. Ten different stromal cells and two pericyte subsets were identified. Applying different R packages (Seurat, SingleR, Velocyto) we established cell cluster diversity and cell lineage/trajectory, while using external data to validate our findings. By understanding healthy regeneration in the described stromal compartments, we aim to identify points of further investigation and possible targets for novel therapy development for benign gynecological disorders affecting endometrial regeneration and proliferation such as endometriosis and Asherman’s syndrome.

Highlights

We found that all expanded endometrial stromal cells (eSCs) express mesenchymal stromal cells (MSCs) surface markers making the distinction between fibroblasts and progenitor cells based on MSC cell surface markers problematic. eSCs were shown to be unique in their immune interactions compared to other MSCs, especially in terms of their lack of histocompatibility complex class II (HLAII) expression post pro-inflammatory stimulation [5]
Using unbiased single-cell transcriptional data, this study demonstrates that the nature of the endometrial stromal compartment is more complex than previously assumed
The gene expression signatures of the stromal subsets we have described in this work; of which three are retained throughout decidualization and early pregnancy, provide a starting point towards understanding the complexity of the greater stromal compartment

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The endometrium is a complex tissue that cyclically regenerates every menstrual cycle in preparation for embryo implantation. Though there is a wealth of research into understanding the endometrial mechanisms involved in the implantation event, far less is known about the tissue’s regenerative properties, akin to scarless wound healing, observed in the proliferative phase. This is important knowledge to understand normal endometrial physiology, and for deciphering the pathophysiology in conditions with impaired endometrial regeneration and proliferation such as Asherman’s syndrome and endometriosis

Objectives

Methods

Conclusion