SERPINE1 (PAI-1) is deposited into keratinocyte migration “trails” and required for optimal monolayer wound repair

Abstract

Cutaneous tissue injury, both in vivo and in vitro, initiates activation of a "wound repair" transcriptional program. One such highly induced gene encodes plasminogen activator inhibitor type-1 (PAI-1, SERPINE1). PAI-1-GFP, expressed as a fusion protein under inducible control of +800 bp of the wound-activated PAI-1 promoter, prominantly "marked" keratinocyte migration trails during the real-time of monolayer scrape-injury repair. Addition of active recombinant PAI-1 to wounded wild-type keratinocyte monolayers as well as to PAI-1 −/− MEFs and PAI-1 −/− keratinocytes significantly stimulated directional motility above basal levels in all cell types. PAI-1 expression knockdown or antibody-mediated functional inhibition, in contrast, effectively attenuated injury repair. The defect in wound-associated migratory activity as a consequence of antisense-mediated PAI-1 down-regulation was effectively reversed by addition of recombinant PAI-1 immediately after scrape injury. One possible mechanism underlying the PAI-1-dependent motile response may involve fine control of the keratinocyte substrate detachment/re-attachment process. Exogenous PAI-1 significantly enhanced keratinocyte spread cell "footprint" area while PAI-1 neutralizing antibodies, but not control non-immune IgG, effectively inhibited spreading with apoptotic hallmarks evident within 24 h. Importantly, PAI-1 not only stimulated keratinocyte adhesion and wound-initiated planar migration but also rescued keratinocytes from plasminogen-induced substrate detachment/anoikis. The early transcriptional response of the PAI-1 gene to monolayer trauma and its prominence in the injury repair genetic signature are consistent with its function as both a survival factor and regulator of the time course of epithelial migration as part of the cutaneous injury response program.

Confluence switch signaling regulates ECM composition and plasmin proteolytic cascade in keratinocytes

“…The study of PAI-1 function in migration is complicated since this molecule influences migration through proteolytic and non-proteolytic functions by interacting with vitronectin and LDL receptor-related protein (LRP) Czekay et al, 2011). In apparent contradiction with our results, recent studies demonstrate that PAI-1 expression is required to induce optimal migration of keratinocytes (Providence and Higgins, 2004;Providence et al, 2008). This discrepancy may be explained by a dose dependent mechanism since some PAI-1 cellular effects are dose dependent (Bajou et al, 2004;Devy et al, 2002).…”

Inhibition of SERPINE1 Function Attenuates Wound Closure in Response to Tissue Injury: A Role for PAI-1 in Re-Epithelialization and Granulation Tissue Formation

“…Dysregulated PAI-1 expression is a causative factor in aberrant wound healing and fibrosis. Following injury in vitro, PAI-1 is induced and its expression is restricted to the wound margin where it is required for efficient keratinocyte migration [31,34,50]. Coincidentally, uPA expression is also elevated at the migratory cohort [35].…”

Plasminogen activator inhibitor 1: Mechanisms of its synergistic regulation by growth factors

“…Treating cells with PAI-1 neutralizing antibody significantly slowed wound repair (Providence, Higgins et al 2008). It has also been reported that PAI-1 controls uPA-mediated cell migration by balancing cell adhesion and detachment activities (Deng, Curriden et al 1996).…”

“…This is demonstrated by the following observations. PAI-1 is deposited onto the migration trail of keratinocytes during the healing of monolayer wound (Providence, Higgins et al 2008). Addition of active PAI-1 promotes directional migration of both wild type and PAI-1 deficient (PAI-1, -/-) keratinocytes (Providence, Higgins et al 2008).…”

“…Plasminogen activator inhibitor 1 (PAI-1) has important roles in regulating fibrinolysis (Kawasaki, Dewerchin et al 2000;, maintaining the integrity of the extracellular matrix (Degryse, Sier et al 2001) and modulating the motility of cells (Deng, Curriden et al 1996;Providence, Higgins et al 2008). PAI-1 levels are elevated in a variety of diseases including cardiovascular diseases , fibrosis , some malignant tumors .…”