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

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, prominently "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.

PAI-1 expression is required for epithelial cell migration in two distinct phases of in vitro wound repair.

Several proteases and their specific inhibitors modulate the interdependent processes of cell migration and matrix proteolysis as part of the global program of trauma repair. Expression of plasminogen activator inhibitor type-1 (PAI-1), a serine protease inhibitor (SERPIN) important in the control of barrier proteolysis and cell-to-matrix adhesion, for example, is spatially-temporally regulated following epithelial denudation injury in vitro as well as in vivo. PAI-1 mRNA/protein synthesis was induced early after epidermal monolayer scraping and restricted to keratinocytes comprising the motile cohort closely recapitulating, thereby, similar events during cutaneous healing. The time course of PAI-1 promoter-driven PAI-1-GFP fusion "reporter" expression in wound-juxtaposed cells approximated that of the endogenous PAI-1 gene confirming the location-specificity of gene regulation in this model. ERK activation was evident within 5 min after injury and particularly prominent in cells residing at the scrape-edge (suggesting a possible role in PAI-1 induction and/or the motile response) as was myosin light chain (MLC) phosphorylation. Indeed, MEK blockade with PD98059 or U0126 attenuated keratinocyte migration (by > or =60%), as did transient transfection of a dominant-negative ERK1 construct (40% decrease in monolayer repair), and completely inhibited PAI-1 transcript expression. Anti-sense down-regulation of PAI-1 synthesis (by 80-85%), or addition of PAI-1 neutralizing antibodies also inhibited injury site closure over a 24 h period establishing that PAI-1 was required for efficient long-term planar motility in this system. PAI-1 anti-sense transfection or actinomycin D transcriptional blockade, in contrast, did not affect the initial migratory response suggesting that residual PAI-1 protein levels (at least in transfectant cells and actinomycin D-treated cultures) may be sufficient to support early cell movement. Pharmacologic inhibition of keratinocyte MEK signaling effectively ablated scrape-induced PAI-1 mRNA expression but failed to attenuate wound-associated increases in cellular PAI-1 protein levels soon after monolayer injury. Collectively, these data suggest that basal PAI-1 transcripts may be mobilized for initial PAI-1 synthesis and, perhaps, the early motile response while maintenance of the normal rate of migration requires the prolonged PAI-1 expression that typically accompanies the repair response. To assess this possibility, scrape site closure studies were designed using keratinocytes isolated from PAI-1-/- mice. PAI-1-/- keratinocytes, in fact, had a significant wound healing defect evident even within the first 6 h following monolayer denudation injury. Addition of active PAI-1 protein to PAI-/- keratinocytes rescued the migratory phenotype that that approximating wild-type cells. These findings validate use of the present keratinocyte model to investigate injury-related controls on PAI-1 gene regulation and, collectively, implicate participation of PAI-1 in two distinct phases of epidermal wound repair.

Elevated sod2 activity augments matrix metalloproteinase expression: evidence for the involvement of endogenous hydrogen peroxide in regulating metastasis.

PURPOSE: Elevated manganese superoxide dismutase (Sod2) levels have been reported to be associated with an increased frequency of tumor invasion and metastasis in certain cancers, and the aim of this study is to examine the molecular mechanisms by which this occurs. EXPERIMENTAL DESIGN: Sod2 and catalase overexpressing HT-1080 fibrosarcoma cell lines were used to evaluate the H(2)O(2)-dependent regulation of matrix metalloproteinase (MMP)-1 promoter activity, mitogen-activated protein (MAP) kinase signaling, DNA-binding activity, and MMP mRNA levels. The invasive and metastatic potential of Sod2 overexpressing cells was characterized using subrenal capsular implantation or tail vein injection of tumor cells into nude mice, respectively. RESULTS: Our data reveal that Sod2 overexpression increases the DNA-binding activity of transcription factors critical for MMP expression but also enhances MMP-1 promoter activity via the Ras//MAP/extracellular signal-regulated kinase (MEK) signaling cascade. A single nucleotide polymorphism that creates an Ets site at position -1607 bp confers Sod2-dependent MMP-1 promoter activity. Sod2 overexpression also increases the mRNA levels of MMPs-2, -3, -7, -10, -9, -11 and enhances the metastatic potential of fibrosarcoma cells when implanted in immunodeficient mice. The Sod2-dependent increases in AP-1 and SP-1 DNA-binding activity, MMP-1 promoter activity, general MMP expression, and collagen degradation can be reversed by the hydrogen peroxide-detoxifying enzyme, catalase. CONCLUSION: MMPs play a critical role in the process of stromal invasion and metastasis, and these findings suggest that the association between increased Sod2 and poor prognosis in certain cancers may be attributed to elevated MMP production.

Epithelial monolayer wounding stimulates binding of USF-1 to an E-box motif in the plasminogen activator inhibitor type 1 gene.

Several proteases and their co-expressed inhibitors modulate the interdependent processes of cell migration and matrix proteolysis during wound repair. Transcription of the gene encoding plasminogen activator inhibitor type 1 (PAI-1), a serine protease inhibitor important in the control of barrier proteolysis and cell-to-matrix adhesion, is spatially-temporally regulated following epithelial denudation injury in vitro as well as in vivo. Using a well-defined culture model of acute epidermal wounding and reepithelialization, PAI-1 mRNA/protein synthesis was induced early after monolayer scraping and restricted to cells comprising the motile cohort. PAI-1 levels in locomoting cells remained elevated (relative to the distal, contact-inhibited monolayer regions) throughout the time course of trauma repair. Targeted PAI-1 downregulation by transfection of antisense PAI-1 expression constructs significantly impaired keratinocyte migration and monolayer scrape wound closure. Injury-induced PAI-1 transcription closely paralleled growth state-dependent controls on the PAI-1 gene. An E-box motif (CACGTG) in the PAI-1 proximal promoter (located at nucleotides -160 to -165), previously shown to be necessary for serum-induced PAI-1 expression, was bound by nuclear factors from wound-stimulated but not quiescent, contact-inhibited, keratinocytes. UV crosslinking approaches to identify E-box-binding factors coupled with deoxyoligonucleotide affinity chromatography and gel retardation assays confirmed at least one major E-box-binding protein in both serum- and wound-activated cells to be USF-1, a member of the helix-loop-helix family of transcription factors. An intact hexanucleotide E-box motif was necessary and sufficient for USF-1 binding using nuclear extracts from both serum- and wound-simulated cells. Two species of immunoreactive USF-1 were identified by western blotting of total cellular lysates that corresponded to the previously characterized phosphorylated and non-phosphorylated forms of the protein. USF-1 isolated by PAI-1 promoter-DNA affinity chromatography was almost exclusively phosphorylated. Only a fraction of the total cellular USF-1 in proliferating cultures, by comparison, was phosphorylated at any given time. PAI-1 E-box binding activity, assessed by probe mobility shift criteria, increased within 2 hours of monolayer scrape injury, a time frame consistent with wound-stimulated increases in PAI-1 transcription. Relative to intact cultures, scrape site-juxtaposed cells had significantly greater cytoplasmic and nuclear USF-1 immunoreactivity correlating with the specific in situ-restricted expression of PAI-1 transcripts/protein in the wound-edge cohort. USF-1 immunocytochemical staining declined significantly with increasing distance from the denudation site. These data are the first to indicate that binding of USF-1 to its target motif can be induced by 'tissue' injury in vitro and implicate USF-1 as a transcriptional regulator of genes (e.g. PAI-1) involved in wound repair.

Severe occupational traumatic injuries.

Severe occupational traumatic injuries represent a challenge to workers and physicians. Efforts to prevent occupational injuries, such as education, protective equipment, adherence to safety procedures, and personal responsibility, are of critical importance. The physician's role as educator, consultant, and on-site manager of these injuries forms the basis for effective management of severe occupational traumatic injuries. Rapid assessment and treatment by coworkers trained in first aid can be vital in preventing more serious sequelae.

Barrier protection with examination gloves: double versus single.

In a series of experiments, the barrier integrity of single and double vinyl and latex examination gloves were tested for dye and water leaks after being placed under stress. A total of 886 examination gloves (385 vinyl: single, 199; double, 186; and 501 latex: single, 290; double, 211) were tested with a standardized clinical protocol designed to mimic patient care activities. Leakage rates for single or double gloving were significantly higher for vinyl than for latex gloves. Single vinyl gloves were significantly more likely to leak than were double vinyl gloves (51.3% and 19.7%, p < 0.0001). However, there were essentially no differences in leakage rates for single or double latex gloves (4.1% and 3.8%, p = 1). Significantly higher rates of leakage were identified with the water leak test than with the dye test for vinyl (p < 0.001) but not for latex (p = 0.22) gloves. For vinyl but not latex gloves, there were significant differences in leakage rates by brand. We conclude that double gloving offers little advantage during routine procedures associated with minimal stress to the gloves or when latex gloves are worn.

Leakage of latex and vinyl exam gloves in high and low risk clinical settings.

The purpose of this study was to compare leakage rates of used latex and vinyl examination gloves from high and low risk clinical units. A total of 4838 latex and 1008 vinyl examination gloves were collected and tested by the Food and Drug Administration (FDA) watertight leak test: three brands of latex [Brand A: n = 2920; Brand B: n = 284; Brand C: n = 1634; and one brand of vinyl gloves (Brand D: n = 1008]. Seventy percent of latex gloves and 46.7% of vinyl gloves were collected from the high risk units. In general, there were no significant differences in leakage rates for vinyl gloves between high and low risk units. However, latex gloves leaked significantly more often at stress levels 2 and 3 from the high risk units as compared to the low risk units (X2 = 24.6, p < .0001). Regardless of level of stress and duration worn, 85.3% (860/1008) of used vinyl gloves and 18.4% (891/4838) of used latex gloves leaked, p < .001). There were significant differences in leakage rates between the three brands of latex gloves (Brand A, 9.8%; Brand B, 25.1%; Brand C, 30.9%, p < .001). Although latex gloves leaked slightly more frequently as stress level increased, glove material (latex or vinyl) and brand of glove were the most important predictors of leakage.

Differential recovery of cytomegalovirus from cellular and supernatant components of bronchoalveolar lavage specimens.

The recovery of cytomegalovirus from bronchoalveolar lavage (BAL) specimens was compared after inoculation of MRC-5 tube and shell vial cell cultures with four different BAL preparations. Analysis of culture results obtained with 55 cytomegalovirus culture-positive samples showed significant differences in the ability to isolate virus from the supernatant and cellular components of these specimens. There was a 52% reduction in cytomegalovirus recovery and a significant delay in the development of cytopathic effect in cultures inoculated with the cellular component of BAL specimens when compared to cultures inoculated with crude BAL cells and fluid. The mean time for detection of cytopathic effect was 11.8 days in tubes inoculated with crude BAL and 18.2 days for tubes inoculated with BAL cells. A similar effect was observed using a rapid shell vial culture technique. A 39% reduction in the number of isolates and a 57% reduction in the number of positive cells were observed in vials inoculated with cells when compared to cultures inoculated with crude BAL. By contrast, using cell-free BAL supernatant as inoculum did not reduce the number of positive cultures or delay development of cytopathic effect. The results suggest that in most BAL specimens, cytomegalovirus is associated with the cell-free, rather than the cellular, component. Although BAL cell concentrates frequently are used for cultivation of viruses from BAL, our results showed that the use of these preparations results in a significant number of false-negative cytomegalovirus cultures.

In-use comparison of latex gloves in two high-risk units: surgical intensive care and acquired immunodeficiency syndrome.

This study was designed to compare use patterns and leakage of gloves from two high-risk units: a surgical intensive care unit (SICU) and an acquired immunodeficiency syndrome (AIDS) unit. During a 3-month interval, the use of gloves during clinical procedures by nursing personnel was observed and recorded. A total of 2900 latex examination gloves were collected and tested in the laboratory by the watertight leakage test: 59% (1714) were from the SICU and 41% (1186) from the AIDS unit. Twenty-four percent (700) of all gloves leaked: 29% (500/1714) leaked when worn by staff in the SICU as compared with 17% (200/1186) leakage rate in the AIDS unit (chi-square = 57.32, p less than 0.05). This difference could be attributed in part to higher levels of stress to the gloves and longer wearing time in the SICU.