"PED/PEA-15 regulates wound healing and angiogenesis by affecting cytoskeletal organization and cell motility: a model for diabetic complications"

Failure in wound healing is a common feature of diabetes mellitus which severely affects morbidity and mortality. We evaluated wound healing in the skin of transgenic mice (TgPED) over-expressing ped/pea-15, a gene over-expressed in patients with type 2 diabetes.Up to four days after the injury, the distance between wound edges was 3-fold higher in TgPED mice compared to their wild-type littermates (Wt). TgPED mice also presented significantly reduced granulation tissue formation as compared to Wt. Moreover, the wounded skin of TgPED exhibited also a reduced content of activated fibroblasts, collagen fibres and an increased detection of infiltrated inflammatory cells. These histological alterations were accompanied, in TgPED speciments, by an increased production of inflammatory cytokines and a defect of neo-angiogenesis process. Then we isolated endothelial cells and fibroblasts from TgPED and Wt mice, mainly involved in the formation of the granulation tissue, the first regenerative tissue that closes the skin gap. Endothelial cells and skin fibroblasts isolated from TgPED and Wt mice showed reduced healing ability in scratch wound healing assays compared to control cells. Furthermore, in time-lapse experiments, TgPED fibroblasts displayed about 2-fold lower velocity and diffusion coefficient, as compared with Wt. These changes were accompanied by reduced spreading and decreased formation of stress fibres and focal adhesion plaques. At molecular level, TgPED fibroblasts displayed decreased RhoA membrane content and increased cytosolic abundance of phosphorylated ERK1/2. Inhibition of ERK1/2 activity by PD98059 restored RhoA membrane translocation, cytoskeleton organization and cell motility and almost completely rescued wound healing ability of TgPED fibroblasts and can be expanded to endothelial cells. Interestingly, fibroblasts isolated from ped/pea-15 null mice (KO) displayed an increased motility and spreading compared to control cells. These results strongly support a role of PED/PEA-15 in the regulation of cell motility during skin wound healing. Moreover, the control exerted by PED/PEA-15 on cell migration is not restricted to fibroblasts. Considering the different known cellular function of PED/PEA-15 in a chronic disorder such as diabetes, the observation that PED/PEA-15 regulates cellular motility and skin wound healing in TgPED mice may suggest these mice as model to study the role of PED/PEA-15 in diabetic complications.