Screening of Key Proteins Related to TGF-β1 Regulating Valve Interstitial Cell Activation via iTRAQ-Based Proteomics
YOU Wanning1, JIN Lianchi1, LAI Yongjie2*
The differentiation of VICs (valve interstitial cells) from fibroblast like phenotype to myofibroblast phenotype, which can be termed “activation” of VICs, is an early hallmark of the onset of valvular fibrosis, and TGF-β1 (transforming growth factor-β1) is a putative cytokine that induces the activation of VICs. In this paper, differential proteomic analysis of primary VICs pre and post TGF-β1 treatment was carried out by iTRAQ (isobaric tags for relative and absolute quantification) technology to discover the novel proteins related to the activation of VICs. In this study, primary rat VICs culture system was established, and bioinformatics method was used to analyze the changes of protein expression profiles of VICs treated with TGF-β1. The differential expression of candidate proteins were validated by qRT-PCR and Western blot assay. The results showed that a total of 7 104 quantifiable proteins were identified, including 404 up-regulated proteins and 494 down-regulated proteins with significant differences (P<0.05). GO enrichment analysis revealed that multicellular biological process, DNA binding functions and extracellular matrix region components were the mainly enriched GO terms. KEGG analysis showed that the differential proteins were mainly involved in DNA replication, mismatch repair and focal adhesion and other signaling pathways. This study comprehensively analyzed the differential protein expression profiles of VICs pre and post TGF-β1 treatment, and identified five candidate proteins (including AKAP12, FBLN2, NCAM1, MFAP4 and CADM4) related to the activation of VICs, providing new insights into the mechanisms of VICs activation and valvular heart disease.
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