- Vimentin is a type III intermediate filament protein that plays a pivotal role in the structural reorganization and phenotypic transformation of cells undergoing epithelial-to-mesenchymal transition (EMT).
- While vimentin is minimally expressed in normal epithelial cells, its expression is strongly upregulated during EMT, marking a shift toward a mesenchymal phenotype. This makes vimentin one of the most widely recognized mesenchymal markers and a key indicator of EMT activation.
- Vimentin contributes significantly to cytoskeletal reorganization. It provides structural support to cells, helping them adopt a fibroblast-like morphology and enabling the dynamic cytoskeletal rearrangements required for cell migration. This is particularly important in processes such as wound healing, embryogenesis, and cancer metastasis, where cell motility is essential. Vimentin helps maintain the mechanical stability of mesenchymal cells and assists in forming the filopodia and lamellipodia, cellular protrusions crucial for migration.
- The expression of vimentin during EMT is tightly regulated by several EMT-related transcription factors, including Snail, Slug, Twist, and ZEB1, which drive the transcriptional programs that promote mesenchymal characteristics. These transcription factors can be activated by growth factors such as TGF-β (Transforming Growth Factor-beta), TNF-α (Tumor Necrosis Factor-alpha), and Wnt signaling pathways, which are involved in inflammation, fibrosis, and cancer progression.
- In pathological conditions, vimentin expression is commonly linked to increased cell motility, invasion, and metastasis. For example, in cancer, the upregulation of vimentin is often associated with poor prognosis, as it enables tumor cells to invade surrounding tissues and spread to distant sites. Similarly, in fibrotic diseases, excessive vimentin expression can contribute to the accumulation of mesenchymal cells that promote tissue stiffness and scarring. In chronic inflammatory conditions, such as those caused by bacterial infections or autoimmune diseases, vimentin’s role in mediating cellular responses to inflammation further underscores its importance in EMT and disease progression.
- Thus, vimentin serves not only as a marker of EMT but also as a functional mediator that enhances the invasive capacity of cells. Its role in enabling structural plasticity and motility makes it a key player in both physiological and pathological EMT processes.
