Deciphering mesenchymal drivers of human Dupuytren's disease at single-cell level.

Dupuytren's disease (DD) is a common, progressive fibroproliferative disease affecting the palmar fascia of the hands, causing fingers to irreversibly flex towards the palm with significant loss of function. Surgical treatments are limited, therefore effective new therapies for DD are urgently required. To identify key cellular and molecular pathways driving DD we employed single-cell RNA sequencing (scRNA-seq), profiling the transcriptomes of 35,250 human single cells from DD, non-pathogenic fascia, and healthy dermis. We identify a DD-specific population of pathogenic PDPN+/FAP+ mesenchymal cells displaying elevated expression of fibrillar collagens and profibrogenic genes. In silico trajectory analysis reveals resident fibroblasts to be the source of this pathogenic population. To resolve the processes governing DD progression, genes differentially expressed during fibroblast differentiation were identified including upregulated TNFRSF12A and transcription factor SCX. Knockdown of SCX and blockade of TNFRSF12A inhibited proliferation and altered pro-fibrotic gene expression of cultured human FAP+ mesenchymal cells, demonstrating a functional role for these genes in DD. The power of scRNA-seq is utilised to identify the major pathogenic mesenchymal subpopulations driving DD and key molecular pathways regulating the DD-specific myofibroblast phenotype. Using this precision medicine approach, inhibition of TNFRSF12A has shown potential clinical utility in the treatment of Dupuytren's disease.