Abstract
Venous leg ulcers (VLUs) are the most common cause of leg ulcers, yet only 44% heal with standard-of-care treatment, highlighting the critical need for better understanding of their cellular pathology. We used both bulk and single-cell RNA sequencing (scRNA-seq) to identify molecular mechanisms and cellular functions contributing to VLU pathophysiology. scRNA-seq of chronic VLUs revealed impairments in immune, lymph endothelial, and endothelial cells, along with underlying signaling pathways. Next, bulk RNA-seq was performed alongside weekly wound assessments over 4 weeks in patients with VLUs receiving standard care, classifying them as healers or nonhealers on the basis of ≥50% closure. Transcriptomes of healing and nonhealing VLUs were compared with those of human acute wounds, revealing marked suppression of inflammatory response, lymphangiogenesis, and angiogenesis in nonhealing VLUs. In contrast, healing VLUs resembled the gene expression signature of physiological, acute wound healing. Reduced inflammatory response underlined the nonhealing VLU signature, associated with impaired leukocyte transmigration and egress, with suppression of the activity of multiple kinases. Bioinformatic analyses pinpointed PTEN (phosphatase and TENsin homolog) as a master regulator of these processes and signaling pathways. Increased PTEN protein expression was confirmed in nonhealing compared with healing VLUs. Furthermore, pharmacological PTEN inhibition enhanced immune response and pro-inflammatory signals, angiogenesis, and lymphangiogenesis, which resulted in accelerated acute wound closure in mice. These findings support PTEN as a key regulator of the nonhealing VLU phenotype controlling multiple processes responsible for impaired wound healing and highlight its potential use as a therapeutic target to promote wound closure in VLUs.