ACLP promotes hypertrophic scar pathogenesis by enhancing myofibroblast activation and cholesterol synthesis-related gene expression.

Hypertrophic scar (HS) is a severe fibrotic disease characterized by excessive fibroblast activation and extracellular matrix deposition. While previous studies have revealed the involvement of Aortic Carboxypeptidase Like Protein (ACLP) in other fibrotic diseases, the role of ACLP in HS has not been investigated. Quantitative real-time PCR (qRT-PCR), Western blotting, and immunofluorescence were applied to investigate the expression and subcellular location of ACLP. Wound healing and Transwell assays were employed to evaluate the impact of ACLP on HSF migration after ACLP siRNA transfection or recombinant human ACLP protein (rACLP) stimulation. The protein expression levels of VIM, MMP2, MMP9, α-SMA, COL I, and COL III in HSFs were also analyzed. A collagen gel contraction assay was harnessed to assess the contractile ability of HSFs after ACLP siRNA transfection or rACLP treatment. Lastly, RNA-Seq was utilized to reveal the gene expression profile of HSFs following ACLP knock-down. ACLP expression was increased in both HS tissues and human hypertrophic scar fibroblasts (HSFs). ACLP knock-down attenuated the horizontal and vertical migration of HSFs, collagen gel contraction activity, fibroblast to myofibroblast transition (FMT), and VIM, MMP2, MMP9, α-SMA, and COL III protein expression. Conversely, rACLP stimulation promoted HSF migration, gel contraction, FMT, and associated protein expression. Additionally, ACLP knock-down downregulated the expression of two cholesterol synthesis-related genes comprising HMGCS1 and HMGCR. Here, for the first time, we reveal that ACLP expression is upregulated during HS and that it promotes HSF migration and myofibroblast activation. Hence, ACLP may serve as a candidate biomarker for HS pathogenesis and as an intervention target for HS prevention and treatment.