Endometrial macrophages in health and disease

IL-4-induced M2 macrophages inhibit fibrosis of endometrial stromal cells

BACKGROUND

Intrauterine adhesions (IUA) refers to endometrial fibrosis caused by irreversible damage of the endometrial basal layer. As the key regulators in tissue repair, regeneration, and fibrosis, macrophages play an essential role in endometrial regeneration and repair during the normal menstrual cycle. However, the mechanism of macrophages involved in IUA remains unclear.

METHODS

In the late stages of proliferation, the endometrium was collected to make paraffin sections. HE and Masson staining were used to observing endometrial morphology and endometrial fibrosis. Immunohistochemistry and Western blotting were used to detect the expression level of fibrosis indexes COL1A1 and α-SMA. The macrophage infiltration was evaluated by immunohistochemistry for the expression levels of CD 206 and CD163. Next, we cultured the primary human endometrial stromal cells (HESCs), and then an IUA cell model was established with 10 ng/ml TGF-β1 for 72 h. THP 1 cells were differentiated by 100 ng/ml PMA into macrophages for 48 h, then macrophages were polarized to M2 macrophages by 20 ng/ml IL-4 for 24 h. The culture supernatants (M(IL-4) -S) of M2 macrophages were applied to the IUA cell model. The expression of fibrosis markers was then assessed using immunofluorescence and Western blotting.

RESULTS

The results show that Patients with IUA have fewer endometrial glands and significantly increased fibrosis levels. Moreover, the infiltration of CD206-positive (M2) macrophages was significantly reduced in IUA patients, and negatively correlated with the expression of endometrial fibrosis indexes α-SMA and COL1A1. In addition, the primary HESCs treated with 10 ng/ml TGF-β1 for 72 h were found to have significantly increased levels of fibrosis indexes. Furthermore, supernatants from IL4-induced M2 macrophages inhibit the TGF-β1-induced fibrosis of HESCs.

CONCLUSIONS

M2 macrophages may negatively regulate the expression of COL1A1 and α-SMA, inhibiting the TGF-β1-induced fibrosis of HESCs. Our study suggests that targeting macrophage phenotypes and promoting the polarization of macrophages to M2 may become a novel strategy for the clinical treatment of IUA.

Endometrial TGFβ signaling fosters early pregnancy development by remodeling the fetomaternal interface

The endometrium is a unique and highly regenerative tissue with crucial roles during the reproductive lifespan of a woman. As the first site of contact between mother and embryo, the endometrium, and its critical processes of decidualization and immune cell recruitment, play a leading role in the establishment of pregnancy, embryonic development, and reproductive capacity. These integral processes are achieved by the concerted actions of steroid hormones and a myriad of growth factor signaling pathways. This review focuses on the roles of the transforming growth factor β (TGFβ) pathway in the endometrium during the earliest stages of pregnancy through the lens of immune cell regulation and function. We discuss how key ligands in the TGFβ family signal through downstream SMAD transcription factors and ultimately remodel the endometrium into a state suitable for embryo implantation and development. We also focus on the key roles of the TGFβ signaling pathway in recruiting uterine natural killer cells and their collective remodeling of the decidua and spiral arteries. By providing key details about immune cell populations and TGFβ signaling within the endometrium, it is our goal to shed light on the intricate remodeling that is required to achieve a successful pregnancy.

Exploring the role of macrophages in the progression from atypical hyperplasia to endometrial carcinoma through single-cell transcriptomics and bulk transcriptomics analysis

Introduction

In this study, we aimed to identify key genes in endometrial cancer by conducting single-cell analysis of macrophages.

Methods

We sourced clinical data from the TCGA database as well as supplementary datasets GSE201926 and GSE173682. Using bulk-seq data of atypical endometrial hyperplasia and endometrial cancer, we pinpointed key differentially expressed genes. Single-cell RNA sequencing was utilized for further gene expression analysis. Cluster analysis was conducted on TCGA tumor data, identifying two distinct subtypes. Statistical methods employed included LASSO regression for diagnostic modeling and various clustering algorithms for subtype identification.

Results

We found that subtype B was closely related to cellular metabolism. A diagnostic model was established using LASSO regression and was based on the genes CDH18, H19, PAGE2B, PXDN, and THRB. This model effectively differentiated the prognosis of cervical cancer. We also constructed a prognosis model and a column chart based on these key genes.

Discussion

Through CIBERSORT analysis, CDH18 and PAGE2B were found to be strongly associated with macrophage M0. We propose that these genes influence the transformation from atypical endometrial hyperplasia to endometrial cancer by affecting macrophage M0. In conclusion, these key genes may serve as therapeutic targets for endometrial cancer. A new endometrial cancer risk prognosis model and column chart have been constructed based on these genes, offering a reliable direction for future cervical cancer treatment.

Dysfunctional intercellular communication and metabolic signaling pathways in thin endometrium

Background: The endometrial thickness is a key factor for successful implantation. Thin endometrium is associated with lower implantation rate and pregnancy rate. Lacking of a better understanding for the cellular and molecular mechanisms of thin endometrium, managing patients with thin endometrium still represents a major challenge for clinicians. Methods: In this study, we combined four single-cell RNA sequencing (scRNA-seq) and one bulk sequencing (bulk-seq) data for thin endometrium to perform an integrated analysis for endometrial cells in proliferating phase. Cell proportion and differentially expressed genes (DEGs) were analyzed to determine the disease-specific cell type and signaling pathways. The cell-cell communication among cell types were inferred by "CellChat" to illustrate the differential intercellular communication under normal and thin endometrium conditions. GSEA and GSVA were applied to identify dysfunctional signals and metabolic pathways before and after thin endometrium. Results: Integration of scRNA-seq identified eight cell types. The proportion of stromal cells showed a significant difference between normal and thin endometrial tissue. The DEGs in diverse cell types revealed enriched pathways in a cell-specific manner. Aberrant cell-cell signaling transduction was found in almost all cell types, especially in immune cells and epithelial cells. Furthermore, dysfunctional metabolic signaling pathways were induced in a cell-type dependent way. The down-regulation of carbohydrate metabolism and nucleotide metabolism was observed and the energy metabolism switch was indicated. Conclusion: Conclusively, we discover dysfunctional signals and metabolic pathways in thin endometrium, providing insight into mechanisms and therapeutic strategies for the atrophic endometrium.