Expression of SKALP/elafin during wound healing in human skin

Diagnostic and prognostic role of elafin in skin acute graft versus host disease: a systematic review

BACKGROUND AND OBJECTIVE

Graft versus host disease (GVHD) is the common complication seen after allogeneic hematopoietic stem cell transplantation (HSCT) and a pleomorphic syndrome that resembles autoimmune and other immunologic disorders, leading to profound immune dysregulation and organ dysfunction. The most common targets of GVHD are skin, gastrointestinal tract and liver. GVHD is classified as acute graft versus host disease (aGvHD) if it occurs within the first 100 days after HSCT and chronic graft versus host disease(cGVHD) if it occurs after day 100. The skin is most frequently and earliest affected by aGvHD, followed by the gastrointestinal tract and liver. An ideal biomarker would predict the onset and severity of clinical acute GVHD and help to direct management, and this is an area of active research regarding the use of biomarkers for diagnosis and prognosis of acute GVHD. Recently, elafin has been identified as a potential plasma biomarker for aGVHD.

METHOD

We searched the databases PubMed, Cochrane library, and medRxiv for all studies investigating the Diagnostic or prognostic role of elafin in GVHD. We set the search strategy incorporating the search terms, 'elafin', 'graft versus host', and 'GVHD', and operated using the Boolean operators 'AND', and 'OR'. Thus, retrieved articles were then exported on an Excel® sheet, and duplicates were removed. The systematic review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. After selecting the study based on inclusion criteria, data on study characteristics and biomarker description was extracted on a pre-determined data extraction table on the Microsoft Excel version. The quality assessment of the included studies was determined using the QUIPS tool.

RESULT

The search revealed 547 studies and 6 studies that met the eligibility criteria of this review have been included. The major finding of our study is the significant elevation of elafin in skin aGVHD.

CONCLUSION

Elafin is a significant biomarker for diagnosis and prognosis of skin aGVHD and should be assessed within 2 weeks of the onset of the disease.

Limited utility of plasma elafin as a biomarker for skin graft-versus-host disease following allogeneic stem cell transplantation

BACKGROUND

Acute cutaneous graft-versus-host disease (acGVHD) following haematopoietic stem cell transplant (HSCT) is common but difficult to distinguish from other causes of rash. Plasma elafin has been proposed as a diagnostic and prognostic biomarker of skin GVHD.

AIM

To evaluate the role of plasma elafin as a biomarker in acGVHD in an Indian population.

METHODS

Plasma elafin was evaluated in a prospective study of HSCT recipients, conducted over 2 years, taking measurements at baseline and at onset of skin rash after HSCT. Patients were categorized into those with GVHD rash, those with non-GVHD rash and those with no rash and the three groups were compared.

RESULTS

Two hundred and sixty-one patients with a median age of 16 years (range 1-61 years) and a male predominance (175 : 86 M/F) underwent HSCT during the study period: 56 patients in the GVHD group, 49 in the non-GVHD group and 156 in the no-rash group. The median baseline elafin was similar in all three groups. At the onset of rash, median elafin level was similar between GVHD and non-GVHD rash (34 549 vs. 32 077 pg/mL; P = 0.58) and between GVHD and no rash (34 549 vs. 26 197 pg/mL; P = 0.08). A rise in elafin from baseline was significantly different between GVHD and no rash (P < 0.001) but not between GVHD and non-GVHD rash (P = 0.44).

CONCLUSION

The utility of plasma elafin as a biomarker of skin GVHD is very limited. Plasma elafin, although elevated in cutaneous GVHD, is not helpful in distinguishing between GVHD rash and other causes of rash following HSCT.

Human Inflammatory Neutrophils Express Genes Encoding Peptidase Inhibitors: Production of Elafin Mediated by NF-κB and CCAAT/Enhancer-Binding Protein β

The concept of plasticity of neutrophils is highlighted by studies showing their ability to transdifferentiate into APCs. In this regard, transdifferentiated neutrophils were found at inflammatory sites of autoimmune arthritis (AIA). Exposure of neutrophils to inflammatory stimuli prolongs their survival, thereby favoring the acquisition of pathophysiologically relevant phenotypes and functions. By using microarrays, quantitative RT-PCR, and ELISAs, we showed that long-lived (LL) neutrophils obtained after 48 h of culture in the presence of GM-CSF, TNF, and IL-4 differentially expressed genes related to apoptosis, MHC class II, immune response, and inflammation. The expression of anti-inflammatory genes mainly of peptidase inhibitor families is upregulated in LL neutrophils. Among these, the PI3 gene encoding elafin was the most highly expressed. The de novo production of elafin by LL neutrophils depended on a synergism between GM-CSF and TNF via the activation and cooperativity of C/EBPβ and NF-κB pathways, respectively. Elafin concentrations were higher in synovial fluids (SF) of patients with AIA than in SF of osteoarthritis. SF neutrophils produced more elafin than blood counterparts. These results are discussed with respect to implications of neutrophils in chronic inflammation and the potential influence of elafin in AIA.

Gene expression in stress urinary incontinence: a systematic review

INTRODUCTION

A contribution of genetic factors to the development of stress urinary incontinence (SUI) is broadly acknowledged. This study aimed to: (1) provide insight into the genetic pathogenesis of SUI by gathering and synthesizing the available data from studies evaluating differential gene expression in SUI patients and (2) identify possible novel therapeutic targets and leads.

METHODS

A systematic literature search was conducted through September 2017 for the concepts of genetics and SUI. Gene networking connections and gene-set functional analyses of the identified genes as differentially expressed in SUI were performed using GeneMANIA software.

RESULTS

Of 3019 studies, 4 were included in the final analysis. A total of 13 genes were identified as being differentially expressed in SUI patients. Eleven genes were overexpressed: skin-derived antileukoproteinase (SKALP/elafin), collagen type XVII alpha 1 chain (COL17A1), plakophilin 1 (PKP1), keratin 16 (KRT16), decorin (DCN), biglycan (BGN), protein bicaudal D homolog 2 (BICD2), growth factor receptor-bound protein 2 (GRB2), signal transducer and activator of transcription 3 (STAT3), apolipoprotein E (APOE), and Golgi SNAP receptor complex member 1 (GOSR1), while two genes were underexpressed: fibromodulin (FMOD) and glucocerebrosidase (GBA). GeneMANIA revealed that these genes are involved in intermediate filament cytoskeleton and extracellular matrix organization.

CONCLUSION

Many genes are involved in the pathogenesis of SUI. Furthermore, whole-genome studies are warranted to identify these genetic connections. This study lays the groundwork for future research and the development of novel therapies and SUI biomarkers in clinical practice.

Markers of systemic involvement and death in hospitalized cancer patients with severe cutaneous adverse reactions

BACKGROUND

Severe cutaneous adverse reactions (SCARs) are frequent in inpatient oncology. Early intervention might reduce morbidity, mortality, and hospitalization costs; however, current clinical and histologic features are unreliable SCAR predictors. There is a need to identify rational markers of SCARs that could lead to effective therapeutic interventions.

OBJECTIVE

To characterize the clinical and serologic features of hospitalized patients with cancer who developed SCARs.

METHODS

Retrospective review of 49 hospitalized cancer patients with a morbilliform rash, recorded testing for serum cytokines (interleukin [IL] 6, IL-10, and tumor necrosis factor [TNF] α) or elafin, and a prior dermatology consultation. Patients were categorized as having a simple morbilliform rash without systemic involvement or complex morbilliform rash with systemic involvement.

RESULTS

Fifteen out of 49 patients (30.6%) were deceased at 6 months from time of dermatologic consultation. Elafin, IL-6, and TNF-α were significantly higher in patients who died compared with patients who were still alive at 6 months. IL-6 and IL-10 were significantly higher in patients with a drug-related complex rash.

LIMITATIONS

Retrospective design, limited sample size, and high-risk patient population.

CONCLUSION

In cancer patients with SCARs, elafin, IL-6, and TNF-α levels might predict a poor outcome. Agents directed against these targets might represent rational treatments for the prevention of fatal SCARs.

Protease activity as a prognostic factor for wound healing in venous leg ulcers

BACKGROUND

Venous leg ulcers (VLUs) are a common type of complex wound that have a negative impact on people's lives and incur high costs for health services and society. It has been suggested that prolonged high levels of protease activity in the later stages of the healing of chronic wounds may be associated with delayed healing. Protease modulating treatments have been developed which seek to modulate protease activity and thereby promote healing in chronic wounds.

OBJECTIVES

To determine whether protease activity is an independent prognostic factor for the healing of venous leg ulcers.

SEARCH METHODS

In February 2018, we searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid Embase and CINAHL.

SELECTION CRITERIA

We included prospective and retrospective longitudinal studies with any follow-up period that recruited people with VLUs and investigated whether protease activity in wound fluid was associated with future healing of VLUs. We included randomised controlled trials (RCTs) analysed as cohort studies, provided interventions were taken into account in the analysis, and case-control studies if there were no available cohort studies. We also included prediction model studies provided they reported separately associations of individual prognostic factors (protease activity) with healing. Studies of any type of protease or combination of proteases were eligible, including proteases from bacteria, and the prognostic factor could be examined as a continuous or categorical variable; any cut-off point was permitted. The primary outcomes were time to healing (survival analysis) and the proportion of people with ulcers completely healed; the secondary outcome was change in ulcer size/rate of wound closure. We extracted unadjusted (simple) and adjusted (multivariable) associations between the prognostic factor and healing.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion at each stage, and undertook data extraction, assessment of risk of bias and GRADE assessment. We collected association statistics where available. No study reported adjusted analyses: instead we collected unadjusted results or calculated association measures from raw data. We calculated risk ratios when both outcome and prognostic factor were dichotomous variables. When the prognostic factor was reported as continuous data and healing outcomes were dichotomous, we either performed regression analysis or analysed the impact of healing on protease levels, analysing as the standardised mean difference. When both prognostic factor and outcome were continuous data, we reported correlation coefficients or calculated them from individual participant data.We displayed all results on forest plots to give an overall visual representation. We planned to conduct meta-analyses where this was appropriate, otherwise we summarised narratively.

MAIN RESULTS

We included 19 studies comprising 21 cohorts involving 646 participants. Only 11 studies (13 cohorts, 522 participants) had data available for analysis. Of these, five were prospective cohort studies, four were RCTs and two had a type of case-control design. Follow-up time ranged from four to 36 weeks. Studies covered 10 different matrix metalloproteases (MMPs) and two serine proteases (human neutrophil elastase and urokinase-type plasminogen activators). Two studies recorded complete healing as an outcome; other studies recorded partial healing measures. There was clinical and methodological heterogeneity across studies; for example, in the definition of healing, the type of protease and its measurement, the distribution of active and bound protease species, the types of treatment and the reporting of results. Therefore, meta-analysis was not performed. No study had conducted multivariable analyses and all included evidence was of very low certainty because of the lack of adjustment for confounders, the high risk of bias for all studies except one, imprecision around the measures of association and inconsistency in the direction of association. Collectively the research indicated complete uncertainty as to the association between protease activity and VLU healing.

AUTHORS' CONCLUSIONS

This review identified very low validity evidence regarding any association between protease activity and VLU healing and there is complete uncertainty regarding the relationship. The review offers information for both future research and systematic review methodology.

Impact of chronic sexual abuse and depression on inflammation and wound healing in the female reproductive tract of HIV-uninfected and HIV-infected women

Sexual violence is associated with increased risk of HIV acquisition/transmission in women. Forced sex can result in physical trauma to the reproductive tract as well as severe psychological distress. However, immuno-biological mechanisms linking sexual violence and HIV susceptibility are incompletely understood. Using the Women’s Interagency HIV Study repository, a total of 77 women were selected to form 4 groups, stratified by HIV serostatus, in the following categories: 1) no sexual abuse history and low depressive symptom score (below clinically significant cut-off, scores <16) (Control); 2) no sexual abuse history but high depressive symptom score, ≥16 (Depression); 3) chronic sexual abuse exposure and low depressive symptom score (Abuse); 4) chronic sexual abuse exposure and high depressive symptom score (Abuse+Depression). Inflammation-associated cytokines/chemokines/proteases (TNF-α, IL-6, IL-1α, IL-1β, TGF-β MIP-3α, IP-10, MCP-1, Cathepsin B), anti-inflammatory/anti-HIV mediators (Secretory leukocyte protease inhibitor (SLPI), Elafin, beta defensin 2 (HBD2), alpha defensins (HNP 1–3), Thrombospondin (TSP-1), Serpin A1, A5, Cystatin A, B), and wound-healing mediators (Gro-α, VEGF, PDGF, EGF, FGF, IGF), were measured in cervical-vaginal lavage (CVL) using ELISA. Linear regression was used to model association of biomarkers with depression and abuse as predictor variables; the interaction between depression and abuse was also tested. Anti-HIV activity in CVL was tested using TZM-bl indicator cell line. In HIV-uninfected women, median levels of IL-6 (p = 0.04), IL-1α (p<0.01), TGF-β (p = 0.01), IP-10 (p = <0.01), PDGF (p<0.01) and FGF (p<0.01), differed significantly between groups. Specifically, an association was found between chronic sexual abuse and increased IL-1α (p<0.01), MIP-3α (p = 0.04), IP-10 (p<0.01), Serpin B1 (p = 0.01), FGF (p = 0.04) and decreased TGF-β (p<0.01), MCP-1 (p = 0.02), PDGF (p<0.01). Further, there was evidence of significant interactions between chronic sexual abuse and current depression for IL-1α, IP-10, Serpin A1, Cystatin B, and FGF. In HIV-infected women, median levels of TNF-α (p<0.01), IL-6 (p = 0.05), MIP-3α (p<0.01), and MCP-1 (p = 0.01), differed significantly between groups. Specifically, an association was found between chronic sexual abuse and increased MCP-1 (p = 0.03), Gro-α (p = 0.01) and decreased TNF-α (p<0.01), IL-1α (p = 0.02), MIP-3α (p<0.01) and Cathepsin B (p = 0.03). Current depressive symptoms were associated with significantly decreased MIP-3α (p<0.01). There was evidence of significant interactions between chronic sexual abuse and current depression for MCP-1 and FGF. No significant differences were observed in anti-HIV activity among all eight groups. Heat-map analyses revealed distinct immune network patterns, particularly in the Abuse groups for both HIV-infected and uninfected women. Our data indicates a complex relationship between chronic sexual abuse exposure, depressive symptoms, and FRT immune mediators that are also affected by HIV status. Association of chronic sexual abuse with increase in inflammation-associated cytokine/chemokine expression, along with impaired wound-healing associated growth-factors can create a microenvironment that can facilitate HIV infection. Evaluation of longitudinal changes in exposures and biomarkers are needed to untangle the immuno-biological mechanisms that may put women who endure life-long sexual abuse at increased risk for HIV.

Lung epithelial cells: therapeutically inducible effectors of antimicrobial defense

Lung epithelial cells are increasingly recognized to be active effectors of microbial defense, contributing to both innate and adaptive immune function in the lower respiratory tract. As immune sentinels, lung epithelial cells detect diverse pathogens through an ample repertoire of membrane-bound, endosomal, and cytosolic pattern-recognition receptors (PRRs). The highly plastic epithelial barrier responds to detected threats via modulation of paracellular flux, intercellular communications, mucin production, and periciliary fluid composition. Epithelial PRR stimulation also induces production of cytokines that recruit and sculpt leukocyte-mediated responses, and promotes epithelial generation of antimicrobial effector molecules that are directly microbicidal. The epithelium can alternately enhance tolerance to pathogens, preventing tissue damage through PRR-induced inhibitory signals, opsonization of pathogen-associated molecular patterns, and attenuation of injurious leukocyte responses. The inducibility of these protective responses has prompted attempts to therapeutically harness epithelial defense mechanisms to protect against pneumonias. Recent reports describe successful strategies for manipulation of epithelial defenses to protect against a wide range of respiratory pathogens. The lung epithelium is capable of both significant antimicrobial responses that reduce pathogen burdens and tolerance mechanisms that attenuate immunopathology. This manuscript reviews inducible lung epithelial defense mechanisms that offer opportunities for therapeutic manipulation to protect vulnerable populations against pneumonia.

Pseudomonas aeruginosa LasB protease impairs innate immunity in mice and humans by targeting a lung epithelial cystic fibrosis transmembrane regulator-IL-6-antimicrobial-repair pathway

Background

Pseudomonas aeruginosa lung infections are a huge problem in ventilator-associated pneumonia, cystic fibrosis (CF) and in chronic obstructive pulmonary disease (COPD) exacerbations. This bacterium secretes virulence factors that may subvert host innate immunity.

Objective

We evaluated the effect of P. aeruginosa elastase LasB, an important virulence factor secreted by the type II secretion system, on ion transport, innate immune responses and epithelial repair, both in vitro and in vivo.

Methods

Wild-type (WT) or cystic fibrosis transmembrane conductance regulator (CFTR)-mutated epithelial cells (cell lines and primary cells from patients) were treated with WT or ΔLasB pseudomonas aeruginosa O1 (PAO1) secretomes. The effect of LasB and PAO1 infection was also assessed in vivo in murine models.

Results

We showed that LasB was the most abundant protein in WT PAO1 secretomes and that it decreased epithelial CFTR expression and activity. In airway epithelial cell lines and primary bronchial epithelial cells, LasB degraded the immune mediators interleukin (IL)-6 and trappin-2, an important epithelial-derived antimicrobial molecule. We further showed that an IL-6/STAT3 signalling pathway was downregulated by LasB, resulting in inhibition of epithelial cell repair. In mice, intranasally instillated LasB induced significant weight loss, inflammation, injury and death. By contrast, we showed that overexpression of IL-6 and trappin-2 protected mice against WT-PAO1-induced death, by upregulating IL-17/IL-22 antimicrobial and repair pathways.

Conclusions

Our data demonstrate that PAO1 LasB is a major P. aeruginosa secreted factor that modulates ion transport, immune response and tissue repair. Targeting this virulence factor or upregulating protective factors such as IL-6 or antimicrobial molecules such as trappin-2 could be beneficial in P. aeruginosa-infected individuals.

Alternatives to In Vivo Draize Rabbit Eye and Skin Irritation Tests with a Focus on 3D Reconstructed Human Cornea-Like Epithelium and Epidermis Models

Human eyes and skin are frequently exposed to chemicals accidentally or on purpose due to their external location. Therefore, chemicals are required to undergo the evaluation of the ocular and dermal irritancy for their safe handling and use before release into the market. Draize rabbit eye and skin irritation test developed in 1944, has been a gold standard test which was enlisted as OECD TG 404 and OECD TG 405 but it has been criticized with respect to animal welfare due to invasive and cruel procedure. To replace it, diverse alternatives have been developed: (i) For Draize eye irritation test, organotypic assay, in vitro cytotoxicity-based method, in chemico tests, in silico prediction model, and 3D reconstructed human cornea-like epithelium (RhCE); (ii) For Draize skin irritation test, in vitro cytotoxicity-based cell model, and 3D reconstructed human epidermis models (RhE). Of these, RhCE and RhE models are getting spotlight as a promising alternative with a wide applicability domain covering cosmetics and personal care products. In this review, we overviewed the current alternatives to Draize test with a focus on 3D human epithelium models to provide an insight into advancing and widening their utility.

Culture of Keratinocytes for Transplantation without the Need of Feeder Layer Cells

Patients with large burn wounds have a limited amount of healthy donor skin. An alternative for the autologous skin graft is transplantation with autologous keratinocytes. Conventionally, the keratinocytes are cultured with mouse feeder layer cells in medium containing fetal calf serum (FCS) to obtain sufficient numbers of cells. These xenobiotic materials can be a potential risk for the patient. The aim of the present study was to investigate if keratinocytes could be expanded in culture without the need of a feeder layer and FCS. Keratinocytes were cultured on tissue culture plastic with or without collagen type IV coating in medium containing Ultroser G (serum substitute) and keratinocyte growth factor (KGF). An in vitro skin equivalent model was used to examine the capacity of these cells to form an epidermis. Keratinocytes in different passages (P2, P4, and P6) and freshly isolated cells were studied. Keratinocytes grown on collagen type IV were able to form an epidermis at higher passage numbers than cells grown in the absence of collagen type IV (P4 and P2, respectively). In both cases the reconstructed epidermis showed an increased expression of Ki-67, SKALP, involucrin, and keratin 17 compared to normal skin. Only 50,000 keratinocytes grown on collagen type IV in P4 were needed to form 1 cm2 epidermis, whereas 150,000 of freshly isolated keratinocytes were necessary. Using this culture technique sufficient numbers of keratinocytes, isolated from 1 cm2 skin, were obtained to cover 400 cm2 of wound surface in 2 weeks. The results show that keratinocytes can be cultured without the need of a fibroblast feeder layer and FCS and that these cells are still able to create a fully differentiated epidermis. This culture technique can be a valuable tool for the treatment of burn wounds and further development of tissue engineered skin.

Epidermal elafin expression is an indicator of poor prognosis in cutaneous graft-versus-host disease

Graft-versus-host disease (GVHD) remains a common and potentially life-threatening complication of allogeneic hematopoietic stem cell transplantation. In the skin, GVHD can present in an acute (aGVHD), chronic lichenoid (clGVHD), or chronic sclerotic form (csGVHD). Measuring peripheral blood levels of the keratinocyte-derived protease inhibitor elafin has recently emerged as a promising tool for the diagnosis of cutaneous aGVHD. We evaluated whether the analysis of elafin expression in skin would allow distinguishing aGVHD from drug hypersensitivity rashes (DHR) and whether cutaneous elafin expression would correlate with disease severity or altered prognosis of aGVHD and clGVHD/csGVHD. Skin biopsies from aGVHD (n=22), clGVHD (n=15), csGVHD (n=7), and DHR (n=10) patients were collected and epidermal elafin expression and its association with diverse clinical/histological parameters were analyzed. Acute GVHD and DHR displayed varying degrees of elafin expression. No elafin was detectable in csGVHD, whereas the molecule was increased in clGVHD as compared with aGVHD. Elafin-high aGVHD/clGVHD lesions presented with epidermal thickening and were associated with poor prognosis-i.e., decreased overall survival in aGVHD and corticosteroid resistance in clGVHD. Although cutaneous elafin does not seem to discriminate aGVHD from DHR lesions, our study strongly suggests an association between cutaneous elafin expression and poor prognosis for patients with cutaneous GVHD.

WFDC1 is a key modulator of inflammatory and wound repair responses

WFDC1/ps20 is a whey acidic protein four-disulfide core member that exhibits diverse growth and immune-associated functions in vitro. In vivo functions are unknown, although WFDC1 is lower in reactive stroma. A Wfdc1-null mouse was generated to assess core functions. Wfdc1-null mice exhibited normal developmental and adult phenotypes. However, homeostasis challenges affected inflammatory and repair processes. Wfdc1-null mice infected with influenza A exhibited 2.75-log-fold lower viral titer relative to control mice. Wfdc1-null infected lungs exhibited elevated macrophages and deposition of osteopontin, a potent macrophage chemokine. In wounding studies, Wfdc1-null mice exhibited an elevated rate of skin closure, and this too was associated with elevated deposition of osteopontin and macrophage recruitment. Wfdc1-null fibroblasts exhibited impaired spheroid formation, elevated adhesion to fibronectin, and an increased rate of wound closure in vitro. This was reversed by neutralizing antibody to osteopontin. Osteopontin mRNA and cleaved protein was up-regulated in Wfdc1-null cells treated with lipopolysaccharide or polyinosinic-polycytidylic acid coordinate with constitutively active matrix metallopeptidase-9 (MMP-9), a protease that cleaves osteopontin. These data suggest that WFDC1/ps20 modulates core host response mechanisms, in part, via regulation of osteopontin and MMP-9 activity. Release from WFDC1 regulation is likely a key component of inflammatory and repair response mechanisms, and involves the processing of elevated osteopontin by activated MMP-9, and subsequent macrophage recruitment.

Sheep lung segmental delivery strategy demonstrates adenovirus priming of local lung responses to bacterial LPS and the role of elafin as a response modulator

Viral lung infections increase susceptibility to subsequent bacterial infection. We questioned whether local lung administration of recombinant adenoviral vectors in the sheep would alter the susceptibility of the lung to subsequent challenge with bacterial lipopolysaccharide (LPS). We further questioned whether local lung expression of elafin, a locally produced alarm anti-LPS/anti-bacterial molecule, would modulate the challenge response. We established that adenoviral vector treatment primed the lung for an enhanced response to bacterial LPS. Whereas this local effect appeared to be independent of the transgene used (Ad-o-elafin or Ad-GFP), Ad-o-elafin treated sheep demonstrated a more profound lymphopenia in response to local lung administration of LPS. The local influence of elafin in modulating the response to LPS was restricted to maintaining neutrophil myeloperoxidase activity, and levels of alveolar macrophage and neutrophil phagocytosis at higher levels post-LPS. Adenoviral vector-bacterial synergism exists in the ovine lung and elafin expression modulates such synergism both locally and systemically.

Differential gene expression in cholesteatoma by DNA chip analysis

OBJECTIVES/HYPOTHESIS

In contrast to normal epithelium, the desquamating stratified squamous epithelium of temporal bone cholesteatoma characteristically exhibits sustained hyperproliferative growth and a capacity for bone erosion. We conducted genome-wide microarray analyses to determine the molecular nature of cholesteatoma's biological processes and identify disease-associated, altered gene activity. We tested the hypothesis that genes contributing to the pathophysiology of cholesteatoma are differentially expressed compared to control tissue.

STUDY DESIGN

Prospective experimental analysis.

METHODS

Using new, enhanced microarray platforms and well-annotated human transcriptome probes, we measured global gene expression levels in surgical specimens of cholesteatoma and in the corresponding normal postauricular skin in four patients. Genes of interest were verified by quantitative real time reverse transcriptase polymerase chain reaction analyses using cholesteatoma and postauricular sample pairs (n = 13). External auditory canal skin from six additional patients was also evaluated as a normal control. Immunohistochemistry detected protein expression in tissue sections and the cells involved.

RESULTS

DNA chip analyses identified 282 differentially expressed genes in cholesteatoma compared to control samples. Of these, 104 genes were upregulated and 178 were downregulated. Ontological classifications indicate relationships to cellular processes including receptor binding, cell communication and motion, vitamin metabolism, and cytokine-mediated inflammation. Based on potential involvement in disease pathology, 10 genes were selected and independently verified by quantitative polymerase chain reaction. Immunohistochemical detection of transcobalamin-1 and CCL27 implicates cholesteatoma keratinocytes and dermal endothelial cells as contributors in disease processes.

CONCLUSIONS

We present a comprehensive, human genome-wide survey of disease-associated gene expression that extends the public database and provides new evidence for molecular mechanisms involved in cholesteatoma pathology. Laryngoscope, 123:S1-S21, 2013.

Pivotal role for alpha1-antichymotrypsin in skin repair

α1-Antichymotrypsin (α1-ACT) is a specific inhibitor of leukocyte-derived chymotrypsin-like proteases with largely unknown functions in tissue repair. By examining human and murine skin wounds, we showed that following mechanical injury the physiological repair response is associated with an acute phase response of α1-ACT and the mouse homologue Spi-2, respectively. In both species, attenuated α1-ACT/Spi-2 activity and gene expression at the local wound site was associated with severe wound healing defects. Topical application of recombinant α1-ACT to wounds of diabetic mice rescued the impaired healing phenotype. LC-MS analysis of α1-ACT cleavage fragments identified a novel cleavage site within the reactive center loop and showed that neutrophil elastase was the predominant protease involved in unusual α1-ACT cleavage and inactivation in nonhealing human wounds. These results reveal critical functions for locally acting α1-ACT in the acute phase response following skin injury, provide mechanistic insight into its function during the repair response, and raise novel perspectives for its potential therapeutic value in inflammation-mediated tissue damage.

Antimicrobial peptides and pregnancy

Antimicrobial peptides (AMPs) are small proteins produced by epithelial surfaces and inflammatory cells, which have broad-spectrum antimicrobial and immunomodulatory activities. They are known to be important in a number of infectious and inflammatory conditions and have been shown to be present in a number of sites throughout the female reproductive tract. Inflammation and infection are associated with a number of complications of pregnancy including preterm labor, and AMPs may play a key role in maintaining and protecting pregnancy. The aim of this review is to describe the expression and function of AMPs in the pregnant female reproductive tract and their relation to preterm labor.

Injury is a major inducer of epidermal innate immune responses during wound healing

We examined the importance of injury for the epidermal innate immune response in human skin wounds. We found that injury, independent of infiltrating inflammatory cells, generated prominent chemotactic activity toward neutrophils in injured skin because of IL-8 production. Furthermore, injury was a major inducer of the expression of antimicrobial (poly)peptides (AMPs) in skin wounds. In human skin, these injury-induced innate immune responses were mediated by activation of the epidermal growth factor receptor (EGFR). Consequently, inhibition of the EGFR blocked both the chemotactic activity generated in injured skin and the expression of the majority of the AMPs. The importance of injury was confirmed in mouse experiments in vivo, in which injury independent of infection was a potent inducer of AMPs in skin wounds. To our knowledge, these data thereby provide a previously unreported molecular link between injury and neutrophil accumulation and identify the molecular background for the vast expression of IL-8 and AMPs in wounded epidermis. Conceptually, these data show that the growth factor response elicited by injury is important for the recruitment of neutrophils in skin wounds.

The serine protease marapsin is expressed in stratified squamous epithelia and is up-regulated in the hyperproliferative epidermis of psoriasis and regenerating wounds

The trypsin-like serine protease marapsin is a member of the large protease gene cluster at human chromosome 16p13.3, which also contains the structurally related proteases testisin, tryptase epsilon, tryptase gamma, and EOS. To gain insight into the biological functions of marapsin, we undertook a detailed gene expression analysis. It showed that marapsin expression was restricted to tissues containing stratified squamous epithelia and was absent or only weakly expressed in all other tissues, including the pancreas. Marapsin was constitutively expressed in nonkeratinizing stratified squamous epithelia of human esophagus, tonsil, cervix, larynx, and cornea. In the keratinizing stratified squamous epidermis of skin, however, its expression was induced only during epidermal hyperproliferation, such as in psoriasis and in murine wound healing. In fact, marapsin was the second most strongly up-regulated protease in psoriatic lesions, where expression was localized to the upper region of the hyperplastic epidermis. Similarly, in the hyperproliferative epithelium of regenerating murine skin wounds, marapsin localized to the suprabasal layers, where keratinocytes undergo squamous differentiation. The transient up-regulation of marapsin, which closely correlated with re-epithelialization, was virtually absent in a genetic mouse model of delayed wound closure. These results suggested a function during the process of re-epithelialization. Furthermore, in reconstituted human epidermis, a model system of epidermal differentiation, members of the IL-20 subfamily of cytokines, such as IL-22, induced marapsin expression. Consistent with a physiologic role in marapsin regulation, IL-22 was also strongly expressed in re-epithelializing skin wounds. Marapsin's restricted expression, localization, and cytokine-inducible expression suggest a role in the terminal differentiation of keratinocytes in hyperproliferating squamous epithelia.

Innate immunity and disorders of the female reproductive tract

Sexually transmitted infections, and their associated sequelae, such as tubal infertility, ectopic pregnancy and preterm labour, are a major worldwide health problem. Chlamydia trachomatis infection is thought to be the leading global cause of tubal infertility and tubal ectopic pregnancy. Preterm birth occurs in around 10% of all deliveries, and nearly 30% of preterm deliveries are associated with intrauterine infection. The mucosal innate immune system of the female reproductive tract has evolved to eliminate such sexually transmitted pathogens whilst maintaining its ability to accommodate specialized physiological functions that include menstruation, fertilization, implantation, pregnancy and parturition. The aim of this review was to describe the role and distribution of key mediators of the innate immune system, the natural antimicrobial peptides (secretory leukocyte protease inhibitor, elafin and the defensins) and the pattern recognition toll-like receptors in the normal female reproductive tract and in the context of these pathological processes.

Neutrophil elastase (NE) and NE inhibitors: canonical and noncanonical functions in lung chronic inflammatory diseases (cystic fibrosis and chronic obstructive pulmonary disease)

Proteases and antiproteases have multiple important roles both in normal homeostasis and during inflammation. Antiprotease molecules may have developed in a parallel network, consisting of "alarm" and "systemic" inhibitors. Their primary function was thought until recently to mainly prevent the potential injurious effects of excess release of proteolytic enzymes, such as neutrophil elastase (NE), from inflammatory cells. However, recently, new potential roles have been ascribed to these antiproteases. We will review "canonical" and new "noncanonical" functions for these molecules, and more particularly, those pertaining to their role in innate and adaptive immunity (antibacterial activity and biasing of the adaptive immune response).

SLPI and elafin: one glove, many fingers

Elafin and SLPI (secretory leucocyte protease inhibitor) have multiple important roles both in normal homoeostasis and at sites of inflammation. These include antiprotease and antimicrobial activity as well as modulation of the response to LPS (lipopolysaccharide) stimulation. Elafin and SLPI are members of larger families of proteins secreted predominantly at mucosal sites, and have been shown to be modulated in multiple pathological conditions. We believe that elafin and SLPI are important molecules in the controlled functioning of the innate immune system, and may have further importance in the integration of this system with the adaptive immune response. Recent interest has focused on the influence of inflamed tissues on the recruitment and phenotypic modulation of cells of the adaptive immune system and, indeed, the local production of elafin and SLPI indicate that they are ideally placed in this regard. Functionally related proteins, such as the defensins and cathelicidins, have been shown to have direct effects upon dendritic cells with potential alteration of their phenotype towards type I or II immune responses. This review addresses the multiple functions of elafin and SLPI in the inflammatory response and discusses further their roles in the development of the adaptive immune response.

In vitro skin irritation: facts and future. State of the art review of mechanisms and models

The skin is the main target tissue for exogenous noxes, protecting us from harmful environmental hazards, UV-irradiation and endogenous water loss. It is composed of three layers, whereas the outermost epidermis is a squamous epithelium that mainly consists of keratinocytes. These cells execute a terminal differentiation, which finally results in the assembly of the stratum corneum. This layer, consisting of cornified keratinocytes, is an effective barrier against a vast number of substances. Apart of this, keratinocytes play crucial roles in the immune surveillance and the initiation, modulation and regulation of inflammation in the epidermis. Regarding cutaneous inflammatory reactions, skin irritation is one of the most common adverse effect in humans. For reasons of human safety assessment new chemicals are still evaluated for irritant potentials by application to animals followed by visible changes such as erythema and oedema. Testing for skin irritation in animals potentially cause them pain and discomfort. Furthermore, the results are not always predictive for those found in humans. In order to replace animal testing and to improve the prediction of irritants, the cosmetic and toiletry industry, in Europe represented by Colipa, develops and uses several alternative in vitro test systems. In this respect, the use of in vitro reconstructed organotypic skin equivalents are mostly favored, because of their increasingly close resemblance to human skin. Due to ethical and scientific questions and on account of the 7th amendment of the European Council Directive 76/768/EEC, the authors see the requirement to drive the development of alternative tests for irritants. Therefore, this article centres on cosmetic ingredients and provides the readership an overview of the state of art of cellular mechanisms of skin irritation and summarizes the results of the commonly used skin equivalents to evaluate irritation in vitro.

Mitosis increases levels of secretory leukocyte protease inhibitor in keratinocytes

Chronic wounds are a major health care burden. Multiple factors produced by healing wounds play important roles in efficient and orderly wound healing. Secretory leukocyte protease inhibitor (SLPI) is constitutively expressed in epithelial cells, and its expression is increased by inflammation. SLPI has antimicrobial activities and improves wound healing. We hypothesized that SLPI expression correlates with keratinocyte growth rate and is increased by epidermal growth factor (EGF). Keratinocytes were isolated from neonatal foreskin. Subconfluent and confluent culture conditions were used. SLPI-specific primers were designed for use in quantitative-competitive reverse-transcription polymerase chain reaction assays to detect and quantify SLPI mRNA expression levels. SLPI levels were increased 2-fold in subconfluent cultures and 1.6-fold in confluent cultures to which EGF had been added. Confluent cultures also demonstrated 7-fold (growth factor depleted) and 6-fold (EGF) increase in SLPI RNA copy number, compared to subconfluent cultures. The results indicate that EGF increases SLPI expression.

Elafin, a secretory protein, is cross-linked into the cornified cell envelopes from the inside of psoriatic keratinocytes

Elafin is a serine proteinase inhibitor highly expressed in psoriatic epidermal keratinocytes, but expressed scarcely, if at all, in normal skin. In addition to the proteinase inhibiting domain, elafin contains multiple transglutaminase substrate domains and has been identified as a constituent of the epidermal cornified cell envelope. It also contains a signal peptide sequence, and previous immunoelectron microscopy studies detected elafin in lamellar granules and also in the intercellular spaces. It has not been explained, however, how and when elafin molecules stored in the granules are cross-linked into the cell envelope. In order to elucidate this issue, we performed pre-embedding and postembedding immunoelectron microscopy of elafin and involucrin, another cell envelope constituent, using psoriatic epidermis. Postembedding double immunoelectron microscopy revealed that elafin was within the secretory (lamellar) granules and released into the intercellular spaces when the cell envelope was not formed. In the cells with involucrin-positive cell envelope, elafin immunolabels were localized diffusely within the cells and also along the cell envelope. Pre-embedding immunoelectron microscopy of purified cell envelope from psoriatic scale samples detected involucrin and elafin colocalizing on the cytoplasmic side of the cell envelope. These findings strongly suggest that elafin-containing granules are disintegrated upon the initiation of cell envelope formation, and that elafin is cross-linked on to the involucrin-positive cell envelope from the inside of keratinocytes. It seems that psoriatic keratinocytes utilize elafin as a major component of the cell envelope, consistent with the previously proposed "precursor availability hypothesis".

Arterial elastase activity after balloon angioplasty and effects of elafin, an elastase inhibitor

Increased proteolytic activity may be a factor in intimal hyperplasia after balloon angioplasty (BA). The objectives of this study were to assess elastase activity after BA in a rabbit arterial double-injury model and the effects of elastase inhibition. Elastase activity increased immediately after BA, reached an 8-fold peak at 1 week, and declined to baseline levels by 4 weeks. Elastin zymography showed that the elastase activity was associated predominantly with a molecular mass of 25 kDa. Elastase activity was significantly inhibited in vitro by elafin and phenylmethylsulfonyl fluoride, selective inhibitors of serine elastases. A second group of animals was transfected after BA with a plasmid containing the cDNA for either elafin or a control (chloramphenicol acetyltransferase, CAT) construct by using a hemagglutinating virus of Japan-liposome transfection technique. Arterial segments were obtained at 48 hours, 1 week, and 4 weeks to assess transgene expression, arterial wall elastase activity, and intimal cross-sectional area, respectively. Elafin transgene expression was evident at 48 hours and resulted in a significant (80%) inhibition of elastase activity compared with chloramphenicol acetyltransferase-transfected arteries. There was a 43% reduction in intimal cross-sectional area in elafin-transfected arteries (0.28+/-0.22 versus 0.16+/-0.07 mm(2) for CAT-transfected versus elafin-transfected arteries, respectively; P<0.05). These data suggest that an early increase in serine elastase activity after BA contributes to intimal hyperplasia. Serine elastase inhibition may be a potential therapeutic approach to inhibit intimal hyperplasia.

Elafin is induced in epidermis in skin disorders with dermal neutrophilic infiltration: interleukin-1 beta and tumour necrosis factor-alpha stimulate its secretion in vitro

BACKGROUND

Elafin, an elastase inhibitor produced by keratinocytes, is overexpressed in the subcorneal region of skin affected by psoriasis, a major feature of which is epidermal infiltration by neutrophil leucocytes.

OBJECTIVES

We studied the expression of elafin in the epidermis in other skin disorders characterized by dermal neutrophil infiltration and in skin disorders with dermal lymphocyte infiltration.

PATIENTS/METHODS

We examined biopsies from the lesional skin of patients with Behçet's syndrome, Sweet's syndrome, pyoderma gangrenosum, cutaneous allergic vasculitis and acute bacterial infection (cellulitis), and from the skin of patients with chronic prurigo, discoid lupus erythematosus and psoriasis. We performed in vitro experiments using cultured keratinocytes treated with mediators such as interleukin (IL)-1 beta, tumour necrosis factor (TNF)-alpha, IL-6, neutrophil elastase and interferon (IFN)-gamma.

RESULTS

Anti-elafin antibody showed a strong reaction with the subcorneal region of the epidermis in patients with Behçet's syndrome, Sweet's syndrome, pyoderma gangrenosum, cutaneous allergic vasculitis and acute bacterial infection (cellulitis), but showed no reaction in skin from patients with dermal lymphocyte infiltration such as is seen in chronic prurigo and discoid lupus erythematosus. The in vitro experiments demonstrated that treatment with IL-1 beta and TNF-alpha resulted in 2.6-fold and 4-fold stimulation of elafin secretion, respectively, whereas IL-6, neutrophil elastase and IFN-gamma caused no significant changes in elafin release.

CONCLUSIONS

These results suggest that inflammatory mediators such as IL-1 beta or TNF-alpha secreted by dermal neutrophils may be involved in overexpression of elafin in keratinocytes; this could protect the epidermis from degradation by dermal neutrophil infiltration.

Trout ovulatory proteins: site of synthesis, regulation, and possible biological function

The mRNA transcripts for trout ovulatory proteins (TOPs) are dramatically up-regulated at the time of ovulation. Previous studies indicated that TOPs were produced by the ovaries and were also present in the coelomic fluid that bathes ovulated eggs. In the present study, Western analysis indicated that TOPs were not present in the coelomic fluid prior to ovulation and therefore must be secreted into the coelomic fluid in large quantities during and after ovulation. Using in situ hybridization and immunocytochemistry, TOP mRNA and proteins were localized to the granulosa cell layer of the postovulatory follicle. A whole-follicle in vitro incubation system was used to look at the effects of various mediators on TOP mRNA and protein levels. Results of several different secondary messenger agonists suggest that TOPs are regulated through a G protein-mediated pathway that does not involve cAMP but may involve the activation of protein kinase C. Other agonists that had significant effects on TOP RNA and/or protein included transforming growth factor alpha (TGF-alpha), serine proteases, corticosteroids, bacterial lipopolysaccharide, and the nitric oxide generator SNAP ([+/-]-S-nitroso-N-acetylpenicillamine). Overall, while several compounds caused significant effects, none were able to reproduce the increase in TOP RNA and protein that occurs in vivo, suggesting that the natural mediator of TOPs may still be untested, or that a combination of mediators may be involved. Finally, coelomic fluid inhibited the growth of the Gram negative bacterium, P. aeruginosa, and this inhibition was lost following immunoprecipitation of TOPs. This suggests that one function of TOPs may be to protect ovulated eggs from bacterial infection.

Human elastase 1: evidence for expression in the skin and the identification of a frequent frameshift polymorphism

Human pancreatic elastase 1 is a serine protease which maps to the chromosomal region 12q13 close to a locus for an autosomal dominant skin disease, diffuse nonepidermolytic palmoplantar keratoderma, and was investigated as a possible candidate gene for this disorder. Expression of two elastase inhibitors, elafin and SLPI, has been related to several hyperproliferative skin conditions. elastase 1 is functionally silent in the human pancreas but elastase 1 expression at the mRNA level was detected in human cultured primary keratinocytes. Antibody staining localized the protein to the basal cell layer of the human epidermis at a number of sites including the palmoplanta. Sequencing of genomic DNA from individuals with/without the keratoderma revealed a sequence variant, which would result in a premature truncation of the protein. This sequence variant, however, did not segregate with the skin disease and, indeed, was found to occur at a relatively high frequency in the population. Individuals homozygous for the variant do not have any obvious skin abnormalities. Based on the analysis of the secondary structure of the translated putative protein, the truncation is unlikely to result in knock-out of the elastase, but may cause destabilization of the enzyme-inhibitor complex.

Induction of SLPI (ALP/HUSI-I) in epidermal keratinocytes

Secretory leukocyte protease inhibitor (SLPI) is a small, cationic protein that is known to be constitutively expressed by several glandular epithelia. SLPI inhibits leukocyte-derived proteinases, has anti-HIV-1, antibacterial, and anti-fungal properties, and interferes with the induction of synthesis of proinflammatory mediators in monocytes and macrophages. We now report that at both the mRNA and the protein level, SLPI shows inducible expression in a nonglandular epithelium. A weak expression of SLPI was found in the stratum granulosum of adult normal human epidermis; however, in lesional psoriatic epidermis and in migrating keratinocytes of healing wounds, a strong cytoplasmic staining was seen in the suprabasal keratinocytes. Remarkably, in the dermis adjacent to SLPI-expressing keratinocytes, SLPI was found extracellularly associated with elastin fibers, whereas the dermis in normal skin was negative. In cell culture, SLPI was hardly expressed in monolayers of proliferating keratinocytes. Differentiating cultures with a phenotype of normal skin expressed low levels of SLPI, whereas cultures with a regenerative/psoriatic phenotype expressed high levels. Functional studies with recombinant SLPI indicated that its antibacterial spectrum and potency are distinct from other anti-microbial peptides such as lysozyme and defensins. In view of the multiple functions of SLPI and the inducibility, we propose that it acts as an important first line defence mechanism in cutaneous injury.

Hypertrophic scarring is associated with epidermal abnormalities: an immunohistochemical study

The role of epidermal keratinocytes in the early phases of normal unimpaired wound healing has been studied extensively. However, little is known about the cell biological processes in the epidermis and the basal membrane zone during the later phases of dermal matrix formation and remodelling of the scar tissue. This study investigated epidermal growth and differentiation and maturation of the basal membrane zone. Biopsies were taken from (clinically) hypertrophic and non-hypertrophic scars at 3 and 12 months after a breast-reduction operation. Tissues were analysed using immunohistochemical techniques. The data showed that epidermal abnormalities with respect to differentiation persist up to 3 months, as witnessed by the expression of cytokeratin 16. Remarkably, hypertrophic scars that remained hypertrophic throughout the period of analysis (up to 12 months) showed significantly more cytokeratin 16 expression at 3 months, when compared either with normal scars or with hypertrophic scars that became normal after 12 months. Staining for Ki-67 antigen, a marker for cell proliferation, revealed an increase in basal keratinocyte proliferation rate in 3-month-old hypertrophic scars compared with non-hypertrophic scars. After 12 months, this difference had disappeared completely and the number of cycling basal cells had returned to normal values. Three-month-old hypertrophic scars showed more acanthosis than non-hypertrophic scars of the same age, irrespective of whether they remained hypertrophic or became normal scars. After 12 months, this difference was no longer present. Staining for various heparan sulphate proteoglycan epitopes revealed that restoration of the basal membrane was incomplete at 3 months, but was complete at 12 months with respect to this component. No differences in the expression of several components of the basal membrane zone (heparan sulphate proteoglycan, laminin, tenascin) were noted between hypertrophic and non-hypertrophic scars. These data show that in the early phase of hypertrophic scarring, epidermal abnormalities are found compared with normal wound healing. In addition, early (3 months) epidermal abnormalities are associated with the clinical outcome at 12 months. These findings raise the possibility that the epidermal compartment is involved in the pathogenic process.