TNS1/TAGLN-enriched endometrial stromal cells is associated with a persistent fibrotic microenvironment in intrauterine adhesion

Intrauterine adhesion arise from aberrant repair and fibrotic remodeling after basal endometrial injury. Hysteroscopic adhesiolysis remains the standard treatment, yet postoperative recurrence stays high and durable preventive strategies remain limited. Most studies analyze IUA at the tissue level or in mixed cell populations, leaving the key pathological states and regulatory nodes of endometrial stromal cells insufficiently defined. Here, we integrated bulk transcriptomic data (GSE165321) and single-cell transcriptomic data (GSE215968) from IUA patients and validated findings using a TGF-β1–induced in vitro fibrotic model of human endometrial stromal cells and an in vivo rat IUA model. Differential expression and co-expression network analyses, together with protein–protein interaction mapping and functional annotation, identified TNS1 and TAGLN as key IUA-associated genes. Single-cell analyses showed marked upregulation of TNS1 and TAGLN in stromal cells. Virtual knockout suggested that TNS1 perturbation mainly affected adhesion/calcium-dependent and ion-transport programs, whereas TAGLN perturbation triggered broader alterations in metabolic and inflammation-related pathways; TNS1 knockout also coincided with potential compensatory upregulation of TAGLN. In vitro, TGF-β1 induced a fibrotic phenotype (increased COL1A1, FN1, ACTA2 and reduced COL3A1; elevated fibronectin and α-SMA) and increased TNS1 and TAGLN at both mRNA and protein levels. Flow cytometry showed a higher proportion of TNS1+TAGLN+ cells, accompanied by enhanced collagen-gel contraction and elevated intracellular ROS and mitochondrial superoxide. In the rat model, endometrial destruction, gland loss, and collagen deposition progressed over time. The result of immunohistochemistry, immunofluorescence, and Western blot revealed stage-dependent stromal expression: TNS1 changed most prominently at 4–6 weeks, whereas TAGLN continued to increase at 6–12 weeks. Collectively, our study suggests a pathological stromal cell state characterized by high TNS1/TAGLN expression in IUA, accompanied by adhesion–contraction programs, metabolic/inflammatory perturbations, and oxidative stress, which may help sustain a pro-fibrotic microenvironment and promote disease progression.