Highlight
Pelvic organ prolapse (POP) involves pathological changes in fibroblast phenotypes within vaginal wall tissue, critical for extracellular matrix (ECM) homeostasis. Single-nucleus RNA sequencing identified six distinct fibroblast subpopulations in prolapsed tissue, characterized by pro-inflammatory, matrix-degrading, ECM-synthesizing, and mesenchymal profiles. POP-specific fibroblasts show an aberrant phenotypic transition away from ECM synthesis toward inflammation and matrix degradation, revealing new therapeutic targets.
Study Background
Pelvic organ prolapse (POP) is a prevalent and debilitating condition affecting women’s pelvic floor support, leading to physical discomfort and significant psychosocial impact. It is characterized by descent of pelvic organs due to weakening or disruption of the vaginal wall and associated connective tissues. Despite ongoing research, the cellular and molecular underpinnings of ECM disorganization—a hallmark of POP—remain incompletely elucidated, limiting therapeutic innovation. Fibroblasts, as key cellular regulators of ECM synthesis and remodeling, occupy a central role in maintaining pelvic tissue integrity. However, their heterogeneity and phenotypic adaptations in prolapsed versus healthy vaginal wall tissue have not been fully characterized.
Study Design
This translational study utilized advanced single-nucleus RNA sequencing (snRNA-seq) to characterize cellular transcriptomes from human vaginal wall tissue to dissect fibroblast heterogeneity. Six full-thickness vaginal wall samples were collected from women with advanced-stage POP (stage III or IV), compared with three control samples from women with minimal or no prolapse (stage 0-I), all undergoing hysterectomy for benign disease. Processed single-nucleus suspensions from frozen tissues underwent snRNA-seq, followed by bioinformatic analyses including dimensionality reduction, cell clustering, subtype annotation, Gene Ontology biological process enrichment, and pseudotime trajectory modeling to delineate fibroblast differentiation pathways. Immunofluorescence and in vitro functional assays corroborated bioinformatics findings.
Key Findings
The snRNA-seq dataset comprised 96,622 nuclei from vaginal wall tissues, identifying major cellular compartments: fibroblasts, endothelial cells, and epithelial cells. Fibroblasts displayed predominant enrichment for ECM-related gene expression, emphasizing their central regulatory role. Notably, fibroblast subpopulations exhibited distinct gene expression profiles, with six subtypes demarcated by hallmark genes: COL1A1+ (ECM-synthesis), POSTN+ (mesenchymal), IL6ST+ (pro-inflammatory), MMP2+ (matrix-degrading), among others.
In POP tissues, there was an increased abundance of IL6ST+ pro-inflammatory and MMP2+ matrix-degrading fibroblasts, alongside a reduction of COL1A1+ ECM-synthesizing and POSTN+ mesenchymal fibroblasts. Pseudotime trajectory analysis revealed a pathological shift: fibroblasts favored differentiation trajectories toward inflammatory and degradative states rather than ECM maintenance. Functional enrichment indicated upregulation of ECM remodeling and negative regulation of cell migration and growth processes.
Consistent with transcriptomic data, fibroblasts isolated from prolapsed tissue demonstrated impaired proliferation and migration capacities in vitro, suggesting compromised tissue repair mechanisms. Immunofluorescence validated the spatial and phenotypic alterations of fibroblast subpopulations in POP tissue.
Expert Commentary
This study compellingly links fibroblast phenotypic plasticity with the pathological ECM disorganization observed in POP. The identification of pro-inflammatory and matrix-degrading fibroblast populations illuminates a mechanistic basis for progressive pelvic tissue weakening. These findings align with emerging evidence that chronic inflammation and impaired ECM homeostasis contribute to POP pathophysiology, offering a cellular framework to interpret clinical progression.
While the study’s single-nucleus approach robustly captures transcriptomic heterogeneity, limitations include the relatively small sample size and the cross-sectional design, which precludes temporal causality inference. Future longitudinal studies are warranted to track fibroblast dynamics throughout POP development and to evaluate potential reversibility of pathological phenotypes. Moreover, integrating spatial transcriptomics could enhance understanding of cell-cell interactions within the pelvic microenvironment.
Therapeutically, these insights suggest targeting fibroblast phenotypic modulation—perhaps by inhibiting pro-inflammatory signaling pathways or stimulating ECM synthesis—may yield novel interventions to restore pelvic floor integrity. Such strategies could complement or reduce reliance on surgical treatments with high recurrence rates.
Conclusion
This investigation advances understanding of POP pathogenesis by delineating fibroblast heterogeneity and abnormal phenotypic transitions driving ECM disarray. The shift from an ECM-synthesizing to pro-inflammatory and matrix-degrading fibroblast landscape in prolapsed vaginal wall tissue underlies functional impairment in tissue repair and homeostasis. These findings provide novel cellular targets for therapeutic modulation with potential to improve clinical outcomes in women with POP, addressing a significant unmet need in women’s health.
In conclusion, targeting fibroblast functional states represents a promising translational avenue, warranting further mechanistic and clinical exploration to inform innovative pelvic floor dysfunction therapies.
Funding
The study was supported by institutional research grants and did not report conflicts of interest. Clinical sample collection complied with ethical standards.
References
- Wu C, Zhang S, Zhou Z, Tong X, Chu L, Chen X. Fibroblast heterogeneity and abnormal phenotype transition in vaginal wall prolapse at single-nucleus transcriptional resolution. Am J Obstet Gynecol. 2026 Jul 7. PMID: 42413807.
- Delgado-Rosas F, et al. The role of fibroblasts in pelvic organ prolapse: Pathophysiology and therapeutic perspectives. Int Urogynecol J. 2022;33(5):1233-1245.
- Lien YH, Huang CC, et al. Inflammation and extracellular matrix remodeling in pelvic organ prolapse. Front Cell Dev Biol. 2023;11:1008790.