tRF-Ser-GCT-108 regulates thermal recovery in HUVECs by targeting MAPK1.

Abstract

Transfer RNA-derived fragments (tRFs) are emerging as critical post-transcriptional regulators in stress responses and tissue repair; meanwhile, endothelial cells orchestrate burn-wound vascular recovery by sprouting new vessels, restoring perfusion, and guiding epithelial regeneration. However, the role of tRFs in thermal injury-induced endothelial cell dysfunction remains unexplored. Here, we identify a novel stress-induced tRF, tRF-Ser-GCT-108, as a key suppressor of endothelial cell recovery following thermal damage. Small-RNA sequencing was performed on paired normal and burn-injured human dermis(n = 5). Differentially expressed tRFs were validated by qPCR in both tissues and heat-injured human umbilical vein endothelial cells (HUVECs, 52 °C, 35 s). Functional assays included CCK-8 proliferation, scratch wound closure, Transwell migration, and Annexin V/PI apoptosis profiling. Mechanistic studies integrated in silico target prediction, and Western blotting to confirm direct binding of tRF-Ser-GCT-108 to the 3'-UTR of MAPK1. Small RNA sequencing identified 172 differentially expressed tRFs in burn-injured tissues, with tRF-Ser-GCT-108 exhibiting the most significant upregulation. Functional assays demonstrated that overexpression of tRF-Ser-GCT-108 in heat-injured HUVECs markedly reduced cell proliferation and migration capabilities while inducing a significant increase in apoptosis. Conversely, inhibition of tRF-Ser-GCT-108 normalized these parameters. Mechanistically, Western blot analysis confirmed that tRF-Ser-GCT-108 directly interacts with the 3'-UTR of MAPK1 mRNA, leading to reduced MAPK1 protein levels. This decrease in MAPK1 protein was consistent with reduced mRNA levels and may contribute to disrupted VEGF signaling. tRF-Ser-GCT-108 functions as a stress-responsive endothelial brake that impairs post-burn vascular repair by silencing MAPK1 within the VEGF axis. Therapeutic inhibition of tRF-Ser-GCT-108 represents a novel RNA-based strategy to accelerate burn-wound healing by reactivating endothelial regeneration.