Mechanoregulation of Basal Keratinocyte Migration in Wounded Tissue

项目总结

Project Summary Epithelial homeostasis is maintained by the balance of mechanical forces acting upon cells across the tissue- scale. Injury disrupts this mechanical balance and it is unclear how changing homeostatic mechanical signals impacts cell behavior needed for wound repair. Failure to efficiently repair can lead to fibrotic scarring, chronic non-healing wounds, and contribute to pathology. Epithelial wound repair relies on the migration of basal keratinocytes to the site of damage. While it is known that basal keratinocytes are sensitive to mechanical forces, we lack an understanding of how epithelial injury alters tissue mechanics in vivo and how these wound-induced biophysical changes subsequently coordinate basal keratinocyte behavior needed for wound repair. This study aims to address these issues by using larval zebrafish, which are amenable to real-time, intravital imaging due to their optical transparency. Preliminary live-imaging experiments show that epithelial injury causes rapid basal keratinocyte migration to the wound site, which is needed for efficient repair. Basal keratinocyte migration is dependent on mechanical signals, such as membrane tension due to cell swelling, and is associated with a transient and localized disruption of epithelial tissue architecture at the wound edge. Basal keratinocyte migration can be inhibited by blocking Arp2/3 complex activation or through Talin1 knockdown, suggesting a potential link between mechanical signaling and F-actin or focal adhesion complex remodeling in vivo. Further, transiently weakening cell adhesion to the extracellular matrix alters basal keratinocyte migration, causing poor wound healing, and resulting in chronic disruption of epithelial architecture. This phenotype mimics pathology associated with Kindler Syndrome, a skin disease in which patients show wound healing defects in response to injury. These preliminary observations demonstrate that basal keratinocytes of larval zebrafish respond to mechanical signals in epithelial tissue after injury by initiating a migratory response that is required for efficient wound healing. They also suggest that defective basal keratinocyte migration may contribute to wound healing pathology. The proposed study will investigate how tension sensing by the mechanotransducers Piezo1 and Talin1 regulate wound-induced basal keratinocyte behavior by F-actin and focal adhesion remodeling, respectively. These findings will subsequently be translated to investigate a zebrafish model of Kindler Syndrome to determine the contribution of dysregulated basal keratinocyte behavior to wound healing pathophysiology. To ensure the success of this project, a tailored training plan has been developed that takes advantage of the excellent research environment at the University of Wisconsin – Madison. Dedicated training in the use of the zebrafish model organism for wound healing studies and advanced in vivo imaging techniques for quantifying epithelial tissue mechanics will aid in the completion of the stated aims. This training will facilitate a successful transition to research independence.