Integrated Analysis of Single-Cell and Spatial Transcriptomics in Keloids: Highlights on Fibrovascular Interactions in Keloid Pathogenesis.

Studies on the etiopathogenesis of keloids mostly have focused on fibroblasts and their dysfunction. In this study, two cutting-edge technologies, single-cell RNA sequencing and spatial transcriptomics, were applied to uncover the underlying pathophysiology of keloids. Keloid tissue samples and normal skin control data were analyzed as well as those of patient-matched keloid and normal mature scar. Single-cell RNA sequencing revealed cellular heterogenicity such as fibroblasts, endothelial cells (ECs), and myofibroblasts within the keloids. Spatial transcriptomics results showed that disease-associated fibroblasts were enriched in the deeper keloid areas, mostly located around the spots with endothelial transcripts. Mesenchymal activation was observed in keloid ECs, characterized by dysregulation of TGF-ß/SMAD signaling. Colocalization of mesenchymal and vascular markers through multiplex immunofluorescence suggested mesenchymal activation of keloid ECs. Cell‒cell interaction analysis identified a significant network between keloid fibroblasts and ECs, and this cellular crosstalk was supported by colocalization analysis of spatial transcriptomics. This study depicted the cellular landscape of keloids at a single-cell resolution as well as the integration of single-cell and valuable spatial data of keloids using spatial transcriptomics and multiplex immunofluorescence technologies. Our findings suggested a potential role of fibrovascular communication and mesenchymal activation of ECs that might be involved in the keloid pathogenesis.

Deconvolution of Adult T-Cell Leukemia/Lymphoma With Single-Cell RNA-Seq Using Frozen Archived Skin Tissue Reveals New Subset of Cancer-Associated Fibroblast.

Adult T-cell Leukemia/Lymphoma (ATLL) is a rare aggressive T-cell malignancy caused by human T-cell leukemia virus type 1 (HTLV-1) infection. However, little is known about the underlying activated molecular pathways at the single cell level. Moreover, the intercellular communications between the tumor microenvironment (TME) and tumor cells in this malignancy are currently unknown. Difficulties in harvesting fresh tissue in a clinical setting have hampered our deeper understanding of this malignancy. Herein, we examined ATLL using archived fresh frozen tissue after biopsy using single-cell RNA sequencing (scRNA-seq) with T-cell receptor (TCR) clonal analysis. Highly clonal tumor cells showed multiple activating pathways, suggesting dynamic evolution of the malignancy. By dissecting diverse cell types comprising the TME, we identified a novel subset of cancer-associated fibroblast, which showed enriched epidermal growth factor receptor (EGFR)-related transcripts including early growth response 1 and 2 (EGR1 and EGR2). Cancer associated fibroblasts (CAFs) of ATLL play an important role for CD4 T-cell proliferation via FGF7-FGF1 and PDGFA-PDGFRA/B signaling, and CAFs, particularly EGR-enriched, are also associated with CD8 and NKT expansion by EGFR. These findings suggest a potential targeted therapeutic pathway to better treat this neoplasm.