Hapangama, D. K. | bioRxiv Science

bioRxiv2025

Compound design of a patient-derived 3D cell culture system modelling early peritoneal endometriosis

Peritoneal endometriosis causes pelvic pain and infertility, but the underlying mechanisms related to these symptoms are not fully understood. Endometriosis diagnosis is typically delayed; thus, patient samples are unsuitable to study early endometriosis formation in situ. This study aimed to generate a 3D co-culture model of early peritoneal endometriosis using patient-derived primary cells, providing unique opportunities to examine endometriotic lesion initiation and progression. Peritoneal wash fluid, fallopian tube mesentery and endometrial biopsies were collected from patients undergoing laparoscopic surgery to isolate primary cells. A composite 3D hydrogel construct was assembled by embedding human peritoneal fibroblasts (HPFs) in a Matrigel-collagen I matrix and subsequent seeding with a layer of human peritoneal mesothelial cells (HPMCs). Immunohistological investigation of the composite hydrogel construct confirmed the successful assembly of a simple peritoneum layer model comprising a mesothelial monolayer, basement membrane and underlying fibroblasts, while secretion of tissue plasminogen activator demonstrated functional mesothelial physiology. Endometrial epithelial organoids (EEOs) were co-cultured with endometrial stromal cells (ESCs) to form endometrial assembloids mimicking shed endometrial tissue fragments at menstruation. When transplanted onto the peritoneal layer model, endometrial assembloids adhered, thus simulating early endometriotic lesion formation. Histological analysis demonstrated direct cell-cell contacts between HPMC, HPF and ESC at the endometrial-peritoneal interface, suggesting the involvement of those cell types in lesion initiation. Our modifiable superficial endometriosis model allows for further refinement by the addition of hormones, cytokines and/or other cell types to determine the underlying molecular mechanism involved in endometriotic lesion formation. HighlightO_LISimple peritoneal layer model resembles parietal peritoneum structure and function. C_LIO_LICombined endometrial and peritoneal model mimics early endometriosis formation. C_LIO_LIThe patient-derived multi-cellular model is suitable to study early endometriosis. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/643554v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@8e0639org.highwire.dtl.DTLVardef@3ab7a7org.highwire.dtl.DTLVardef@ef6e81org.highwire.dtl.DTLVardef@13fe704_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2021

S18-phosphorylation of USP7 regulates interaction with TCEAL4 that defines specific complexes and potentially distinct functions.

USP7 is a nuclear deubiquitylase (DUB) with multiple cancer-associated substrates for which selective inhibitors are available, yet it remains unclear how the pleiotropic effects of USP7 are regulated. We report that S18-phosphorylation does not influence USP7 catalytic activity but instead confers selectivity for protein interactions. In particular, non-S18-phosphorylatable USP7 preferentially interacts with USP11 and TRIM27, together with TCEAL1 and TCEAL4 whose functions are unknown. Intriguingly, USP7 can interact with two cellular forms of TCEAL4, but USP11 only interacts with a lower abundance K142 mono-ubiquitylated form (TCEAL4-Ub), which can scaffold a complex containing both DUBs. Whilst USP11 and TCEAL4 are both USP7 substrates, TCEAL4-Ub levels are specifically maintained by USP11 with their levels positively correlated in cancer cell lines. Together these data illustrate how USP7 phosphorylation and TCEAL4 ubiquitylation combine to define distinct USP7 complexes. As TCEAL4 itself interacts with proteins involved in ubiquitylation and various forms of DNA regulation, these complexes may direct cellular activity of USP7.

cell biology↗