2. Academic Validation
  3. ALA-PDT promotes the death and contractile capacity of hypertrophic scar fibroblasts through inhibiting the TGF-β1/Smad2/3/4 signaling pathway

ALA-PDT promotes the death and contractile capacity of hypertrophic scar fibroblasts through inhibiting the TGF-β1/Smad2/3/4 signaling pathway

  • Photodiagnosis Photodyn Ther. 2023 Dec 20:45:103915. doi: 10.1016/j.pdpdt.2023.103915.
Zilu Qu 1,  Yao Chen 1,  Kun Du 2,  JiaXi Qiao 3,  Liuqing Chen 1,  Jinbo Chen 4,  Li Wei 5
Affiliations

Affiliations

  • 1 Department of Dermatology, Wuhan No. 1 Hospital, Wuhan 430022, China; Hubei Province & Key Laboratory of Skin Infection And Immunity, Wuhan No. 1 Hospital, Wuhan 430022, China.
  • 2 Medical Engineering Section, Wuhan No. 1 Hospital, Wuhan 430022, China.
  • 3 Department of Dermatology, Wuhan No. 1 Hospital, Wuhan 430022, China.
  • 4 Department of Dermatology, Wuhan No. 1 Hospital, Wuhan 430022, China; Hubei Province & Key Laboratory of Skin Infection And Immunity, Wuhan No. 1 Hospital, Wuhan 430022, China. Electronic address: chen999jb@163.com.
  • 5 Deans Office,Wuhan No. 1 Hospital, Tongji Medical College, Wuhan 430022, China. Electronic address: whyyywl@163.com.
PMID: 38128289 DOI: 10.1016/j.pdpdt.2023.103915
Abstract

Background: Hypertrophic scars, an abnormal wound-healing response to burn injuries, are characterized by massive fibroblast proliferation and excessive deposition of extracellular matrix and collagen. 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) is a promising therapy for hypertrophic scar, details of the mechanisms remain to be elucidated. In this study, we aimed to investigate the molecular mechanisms involved in ALA-PDT against hypertrophic scar fibroblasts.

Methods: The morphologies of hypertrophic scar fibroblasts (HSFs) treated with ALA-PDT were observed under a LIGHT microscopy. The viability of HSFs was detected using the CCK-8 assay. HSFs-populated collagen gel contraction assays were conducted to examine the fibroblast contractility and the cytotoxicity of HSFs in 3D collagen tissues were observed using confocal microscopy. The effect of ALA-PDT on TGF-β1/SMAD2/3/4 signaling pathway activation and effector gene expression were verified by immunoprecipitation, western blot and real-time quantitative PCR analysis.

Results: We observed significant changes in cell morphology after ALA-PDT treatment of HSFs. As ALA concentration and LIGHT dose increased, the viability of HSFs significantly decreased. ALA-PDT can significantly alleviate the contractile capacity and promote the death of HSFs induced by TGF-β1 treatment in a three-dimensional collagen culture model. TGF-β1 treatment of HSFs can significantly induce phosphorylation of SMAD2/3 (p-Smad2/3) in whole cells, as well as p-Smad2/3 and SMAD4 proteins into the nucleus and increase the mRNA levels of collagen 1/3 and α-SMA. ALA-PDT hampers the TGF-β1-Smad2/3/4 signaling pathway activation by inducing K48-linked ubiquitination and degradation of SMAD4.

Conclusions: Our results provide evidence that ALA-PDT can inhibit fibroblast contraction and promote cell death by inhibiting the activation of the TGF-β1 signaling pathway that mediates hypertrophic scar formation, which may be the basis for the efficacy of ALA-PDT in the treatment of hypertrophic scars.

Keywords

ALA-PDT; Fibroblast; Hypertrophic scars; Photodynamic therapy; TGF-β1/Smad signaling; Ubiquitination.

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