Modulating hypertrophic scar formation by targeting endothelial transient receptor potential vanilloid-1/nuclear factor kappa-B/interleukin-6 axis to regulate angiogenesis

Background: Noxious lifestyle factors including spicy diets and hot baths may lead to scar formation and recurrence. These phenomena are related to the activation of the transient receptor potential vanilloid-1 (TRPV1) cation channel. Our previous study revealed significant upregulation of TRPV1 expression in the dermis of hypertrophic scar (HS), while the exact underlying mechanism of TRPV1 activation in HS remains ill-defined. This study aims to clarify the contribution of TRPV1 activation to HS pathogenesis, particularly in relation to aberrant angiogenesis. Methods: First, this study employs single-cell RNA sequencing technology to analyze the association between vascular endothelial cells and the development of HS. Complementarily, bioinformatics analysis combined with histological validation is utilized to investigate the relationship between TRPV1 channels and aberrant angiogenesis within HS formation. Furthermore, the correlation between TRPV1 activation and HS phenotypes is rigorously validated at the in vivo level. In parallel, in vitro experiments are conducted to elucidate the impact of TRPV1 channel activation on the biological behaviors and functions of vascular endothelial cells. Subsequently, key downstream signaling pathways of TRPV1 are screened, and their molecular mechanisms in regulating vascular endothelial cell-mediated angiogenesis are systematically verified. Finally, a comprehensive analysis is performed to establish the clinical relevance of the TRPV1/nuclear factor kappa-B (NF-κB)/interleukin-6 (IL-6) axis with vascularization severity and adverse prognostic outcomes in hypertrophic scarring. Results: Single-cell RNA sequencing revealed significant cellular heterogeneity in vascular endothelial cells between normal skin and HS, indicating activated angiogenesis and substantial vascular endothelial cell alterations during HS development. Bulk RNA-seq and clinical analyses further confirmed this angiogenesis activation, demonstrating a close association with TRPV1 channel activation. In vivo studies established that capsaicin (CAP)-induced TRPV1 activation exacerbated HS progression through enhanced angiogenesis, whereas TRPV1 ablation or local inhibition markedly attenuated this effect. In vitro experiments demonstrated that TRPV1 activation regulated angiogenesis by promoting pro-angiogenic phenotypes. Transcriptomic analysis and functional validation identified the IL-6/signal transducer and activator of transcription 3 pathway as a downstream NF-κB-dependent pro-angiogenic axis mediated by TRPV1 in HS vascular endothelial cells. Critically, dermal overexpression of the TRPV1/NF-κB/IL-6 axis in HS patients correlated strongly with both disease severity and recurrence. Conclusions: Here, we show that the development of HS is strongly correlated with endothelial angiogenic activity. TRPV1 activation by CAP enhances proangiogenic processes including endothelial proliferation, migration, and tubule formation, while reducing apoptosis through the TRPV1/NF-κB/IL-6 axis. In a rabbit ear HS model, stimulation of TRPV1 contributes to the formation of HS via the TRPV1/NF-κB/IL-6 axis, whereas pharmacological ablation of TRPV1 significantly reversed these phenotypes. These findings shed light on the underlying molecular mechanisms and provide a potential therapeutic target for HS.