Single-cell profiling identifies distinct hormonal, immunologic, and inflammatory signatures of endometriosis-constituting cells, 2023, Shin et al.

[SNT Gatchaman]

Single-cell profiling identifies distinct hormonal, immunologic, and inflammatory signatures of endometriosis-constituting cells
Sun Shin; Youn-Jee Chung; Seong Won Moon; Eun Ji Choi; Mee-Ran Kim; Yeun-Jun Chung; Sug Hyung Lee

Endometriosis consists of ectopic endometrial epithelial cells (EEECs) and ectopic endometrial stromal cells (EESCs) mixed with heterogeneous stromal cells.

To address how endometriosis-constituting cells are different from normal endometrium and among endometriosis subtypes and how their molecular signatures are related to phenotypic manifestations, we analyzed ovarian endometrial cyst (OEC), superficial peritoneal endometriosis (SPE), and deep infiltrating endometriosis (DIE) from 12 patients using single-cell RNA-sequencing (scRNA-seq).

We identified 11 cell clusters, including EEEC, EESC, fibroblasts, inflammatory/immune, endothelial, mesothelial, and Schwann cells. For hormonal signatures, EESCs, but not EEECs, showed high estrogen signatures (estrogen response scores and HOXA downregulation) and low progesterone signatures (DKK1 downregulation) compared to normal endometrium. In EEECs, we found MUC5B + TFF3 low cells enriched in endometriosis. In lymphoid cells, evidence for both immune activation (high cytotoxicity in NK) and exhaustion (high checkpoint genes in NKT and cytotoxic T) was identified in endometriosis.

Signatures and subpopulations of macrophages were remarkably different among endometriosis subtypes with increased monocyte-derived macrophages and IL1B expression in DIE. The scRNA-seq predicted NRG1 (macrophage)-ERBB3 (Schwann cell) interaction in endometriosis, expressions of which were validated by immunohistochemistry. Myofibroblast subpopulations differed according to the location (OECs from fibroblasts and SPE/DIEs from mesothelial cells and fibroblasts). Endometriosis endothelial cells displayed proinflammation, angiogenesis, and leaky permeability signatures that were enhanced in DIE.

Collectively, our study revealed that (1) many cell typesendometrial, lymphoid, macrophage, fibroblast, and endothelial cells—are altered in endometriosis; (2) endometriosis cells show estrogen responsiveness, immunologic cytotoxicity and exhaustion, and proinflammation signatures that are different in endometriosis subtypes; and (3) novel endometriosis-specific findings of MUC5B + EEECs, mesothelial cell-derived myofibroblasts, and NRG1-ERBB3 interaction may underlie the pathogenesis of endometriosis. Our results may help extend pathologic insights, dissect aggressive diseases, and discover therapeutic targets in endometriosis.

Link | Paywall (The Journal of Pathology)

 

[SNT Gatchaman]

It is generally agreed that the immune reaction to endometriosis does not eradicate ectopic tissues and is rather misdirected, resulting in the survival of ectopic tissues and the induction of inflammatory and angiogenic reactions. An earlier scRNA-seq study found Treg and NK cell alterations accounting for immunotolerance in endometriosis. At the same time, the researchers observed CCL19 + perivascular cells with immune cell trafficking in endometriosis accounting for immune activation. In our study, we discovered increased cytotoxicity scores in NK subpopulations and immune checkpoint gene expressions in NKT and Tcyt in OEC, SPE, and DIE, accounting for both immune overload and inactivation in endometriosis. These results suggest that altered immunologic reaction is a general feature of endometriosis. Immunologic exhaustion arises in chronic infection, cancer, and immune-mediated inflammatory diseases due to long-time exposure to antigens, which is consistent with the disease chronicity of endometriosis.

Previously, evidence for mesothelial to myofibroblast differentiation was identified in endometriosis, but the difference from fibroblast-derived myofibroblasts remained unknown. Differentially expressed genes include matrix genes (COL4A1, COL4A2, and TNC) and growth regulation genes (INHBA, SFRP1, FGF7, and PARM1) whose functions are diverse and overlapping. Further functional studies are needed to determine the roles of these myofibroblast subpopulations in endometriosis.

our study observed Schwann cells in endometriosis tissues that were predicted to interact with inflammatory cells (NRG1 in Mo-Mac and ERBB3 in Schwann cells). [...] The data indicate that inflammation induced macrophage recruitment might be the background of the interaction for NRG1 in Mo-Mac and ERBB3 in Schwann cells in endometriosis. The data support the notion that macrophages interact with Schwann cells, guiding axonal regeneration and contributing to neuroinflammation and pain generation.