Quantitative proteomic comparison of myofibroblasts derived from bone marrow and cornea

Myofibroblasts are fibroblastic cells that function in wound healing, tissue repair and fibrosis, and arise from bone marrow (BM)-derived fibrocytes and a variety of local progenitor cells. In the cornea, myofibroblasts are derived primarily from stromal keratocytes and from BM-derived fibrocytes after epithelial-stromal and endothelial-stromal injuries. Quantitative proteomic comparison of mature alpha-smooth muscle actin (α-SMA)+ myofibroblasts (verified by immunocytochemistry for vimentin, α-SMA, desmin, and vinculin) generated from rabbit corneal fibroblasts treated with transforming growth factor (TGF) beta-1 or generated directly from cultured BM treated with TGF beta-1 was pursued for insights into possible functional differences. Paired cornea-derived and BM-derived α-SMA+ myofibroblast primary cultures were generated from four New Zealand white rabbits and confirmed to be myofibroblasts by immunocytochemistry. Paired cornea- and BM-derived myofibroblast specimens from each rabbit were analyzed by LC MS/MS iTRAQ technology using an Orbitrap Fusion Lumos Tribrid mass spectrometer, the Mascot search engine, the weighted average quantification method and the UniProt rabbit and human databases. From 2329 proteins quantified with ≥ 2 unique peptides from ≥ 3 rabbits, a total of 673 differentially expressed (DE) proteins were identified. Bioinformatic analysis of DE proteins with Ingenuity Pathway Analysis implicate progenitor-dependent functional differences in myofibroblasts that could impact tissue development. Our results suggest BM-derived myofibroblasts may be more prone to the formation of excessive cellular and extracellular material that are characteristic of fibrosis.