(WHS-L1.03) PTEN IS A MASTER REGULATOR OF NON-HEALING PHENOTYPE IN VENOUS LEG ULCERS
Thursday, May 16, 2024
10:30 AM – 11:30 AM East Coast USA Time
Venous leg ulcers (VLUs) represent one of the most prevalent types of chronic wounds yet only 44.1% of VLUs heal with standard of care, underscoring the critical need to better understand the molecular and cellular pathology of VLUs. This study focused on multi-omic approaches to identify novel therapeutic targets and key cellular and molecular mechanisms that are associated with clinical outcomes of VLU healing. Patients with chronic VLU were recruited from 2 clinical centers. To identify the unique non-healing gene signatures, we performed bulk and single cell RNA sequencing on healing (n=5) and non-healing VLUs (n=6) and utilized Ingenuity Pathway Analysis to perform comparative genomics to human acute wounds (AW) collected at day 3. Immune response of healing VLUs showed a high resemblance to acute wounds, while non-healing VLUs signature showed a strong suppression of the cellular inflammation and, much less studied, lymphangiogenesis. We confirmed these findings in prospectively collected tissue (n=4 per group) by immunostaining. We demonstrated a significant decrease in CD45, CD3, CD4, CD19, CD68 and podoplanin positive cell population in non-healers compared to healers. Further, the absence of a proper inflammatory response was a consequence of multiple impaired cellular processes: suppressed transmigration, improper chemotaxis, and immune cell recruitment, which was corroborated by significant suppression of CCL4, CCL13, CXCL9, CXCL12, CX3CL1, ICAM1, ITGB2, VCAM1, TLR4, and XCR1 in non-healing VLUs. To identify the molecular mechanisms contributing to a non-healing VLU signature, we performed proteome profiler arrays and found suppression of AKT, ERK, p38 MAPK, SRC, STAT and PDGFR signaling pathways in non-healers when compared to healers. Upstream regulator analyses pointed to PTEN as a master negative regulator of all these pathways. PTEN protein analyses showed significant induction in non-healers when compared to healers. Indeed, PTEN inhibitor accelerated wound closure in murine wounds in vivo. In addition to increasing immune cell response, PTEN inhibitor also induced IFNγ and CXCL13. Thus, we identified PTEN as a master regulator of non-healing phenotype of VLUs that orchestrates impaired immune response and lymphangiogenesis. Identifying PTEN signaling and cellular makeup that is critical in promoting VLU healing provides key targets for novel therapeutic approaches that will successfully shift a non-healing to a healing VLU and promote closure.