Secretory Leukocyte Protease Inhibitor Research Articles

Molecular structure, gene expression and functional role of WFDC1 in angiogenesis and cancer

Whey acidic proteins (WAP) perform a diverse range of important biological functions, including proteinase activity, calcium transport and bacterial growth. The WAP four-disulphide core domain protein 1 (WFDC1) gene (also called PS20), encodes the 20 kDa prostate stromal protein (ps20), which is a member of the WAP-type four-disulphide core domain family of proteins, and exhibits characteristics of serine protease inhibitors, such as elafin and secretory leukocyte protease inhibitor. Molecular structural analysis reveals that ps20 consists of four-disulphide bonds formed by eight cysteine residues located at the carboxyl terminus of the protein. Wfdc1-null mice were found to display no overt developmental phenotype, suggesting a dispensable role in organ growth and development. However, WFDC1 was able to mediate endothelial cell migration and pericyte stabilization, which are vital for the formation of functional vascular structures. WFDC1 was also found to be downregulated in cancers and exhibited a regulatory effect on cell proliferation. In addition, it was involved in the modulation of memory T cells during human immunodeficiency virus infection. Gaining a solid understanding of the mechanisms by which WFDC1 regulates tissue homeostasis and disease processes, in a tissue specific manner, will be an important move towards the development of WFDC1/ps20 as potential therapeutic targets.

The interaction of smoking habit, SLPI and AnxA2 in HPV associated head and neck and other cancers

Six own studies confirm a correlation between smoking, expression of the secretory leukocyte protease inhibitor (SLPI, an antileukoproteinase) and expression of Annexin A2 (AnxA2), and their influence on human papilloma virus (HPV)-infections. SLPI and HPV are ligands of AnxA2.This correlation was tested on 928 tissue samples from 892 patients in six independent studies [squamous cell carcinoma of the head and neck (HNSCC), n = 522; non-neoplastic tonsils n = 214; clinically normal mucosa, n = 93 (of these n = 57 were obtained from patients treated for non-malignant diseases and n = 36 were obtained from HNSCC-patients) and vulvar squamous cell carcinoma (VSCC) n = 99]. HPV-DNA-status was determined by GP5+/GP6+-PCR, followed in case of HPV-positivity by Sanger sequencing and RT-PCR using HPV-type specific primers. SLPI- and AnxA2-gene-expression was determined by RT-q-PCR; SLPI-protein-expression was additionally determined by immunohistochemistry (IHC); the data were correlated with each other and with patient characteristics.Smoking results in increased SLPI-gene- and protein- and AnxA2-gene-expression with significantly higher SLPI- than AnxA2-gene-expression. SLPI is decreased in non-smokers with a continuous AnxA2-surplus. HPV-status correlates with smoking habit, with smokers being mostly HPV-negative and non-smokers HPV-positive.We hypothesize that smoking leads to SLPI-overexpression with SLPI-binding to AnxA2. Thus, HPV cannot bind to AnxA2 but this seems pivotal for HPV-cell-entry. Smoking favors SLPI-expression resulting in HPV-negative carcinomas, while HPV-positive carcinomas are more common in non-smokers possibly due to a surplus of unbound AnxA2. In addition, the hypothesis may contribute to understand why smokers show increased oral HPV-prevalence in natural history studies but do not necessarily develop HPV-associated lesions.

Mechanisms involved in regulation of periodontal ligament cell production of pro‐inflammatory cytokines: Implications in periodontitis

It is well recognized that human periodontal ligament cells (PDL cells) may represent local immune cells of the periodontal tissues. However, it is unclear whether they represent “true” immune cells, since they can produce pro‐inflammatory cytokines not only after stimulation with bacterial lipopolysaccharides but also in response to other stimuli such as mechanical stress. Stimulation with bacterial lipopolysaccharides strongly enhances PDL cell production of pro‐inflammatory cytokines through activation of toll‐like receptors and NF‐κB signaling. Less information is available regarding putative modulators of cytokine production and their mechanisms of action in PDL cells. The anti‐inflammatory glucocorticoid dexamethasone reduces lipopolysaccharide‐induced PDL cell production of cytokines. Recent observations show that vitamin D and the antimicrobial peptide LL‐37 antagonize lipopolysaccharide‐stimulated PDL cell production of pro‐inflammatory cytokines. Secretory leukocyte protease inhibitor is endogenously expressed by PDL cells, and this protein negatively regulates PDL cell‐evoked cytokine production. More information and knowledge about the regulation of PDL cell production of cytokines may clarify the role of PDL cells in oral innate immunity and their importance in periodontitis.

A Cluster Analysis of Bronchiectasis Patients Based on the Airway Immune Profile

Clinical heterogeneity in bronchiectasis remains a challenge for improving the appropriate targeting of therapies and patient management. Antimicrobial peptides (AMPs) have been linked to disease severity and phenotype. Can we identify clusters of patients based on the levels of AMPs, airway inflammation, tissue remodeling, and tissue damage to establish their relationship with disease severity and clinical outcomes? A prospective cohort of 128 stable patients with bronchiectasis were recruited across three centers in three different countries (Spain, Scotland, and Italy). A two-step cluster strategy was used to stratify patients according to levels of lactoferrin, lysozyme, LL-37, and secretory leukocyte protease inhibitor in sputum. Measurements of inflammation (IL-8, tumor growth factor β, and IL-6), tissue remodeling and damage (glycosaminoglycan, matrix metallopeptidase 9, neutrophil elastase, and total and bacterial DNA), and neutrophil chemotaxis were assessed. Three clusters of patients were defined according to distinct airway profiles of AMPs. They represented groups of patients with gradually distinct airway infection and disease severity. Each cluster was associated with an airway profile of inflammation, tissue remodeling, and tissue damage. The relationships between soluble mediators also were distinct between clusters. This analysis allowed the identification of the cluster with the most deregulated local innate immune response. During follow-up, each cluster showed different risk of three or more exacerbations occurring (P= .03) and different times to first exacerbations (P= .03). Bronchiectasis patients can be stratified in different clusters according to profiles of airway AMPs, inflammation, tissue remodeling, and tissue damage. The combination of these immunologic variables shows a relationship with disease severity and future risk of exacerbations.

Secretory leukocyte protease inhibitor and progranulin as possible regulators of cervical remodeling in pregnancy

Secretory leukocyte protease inhibitor (SLPI) and progranulin (PGRN) are secretory proteins with an anti-inflammatory property. Their involvement in cervical remodeling in pregnant uterus is not yet elucidated. Thus, this study aimed to explore the significance of SLPI and PGRN in the maintenance of pregnancy by investigating the factors associated with their expression levels at the cervix. Concentrations of SLPI and PGRN proteins were measured in cervical mucus samples collected from asymptomatic pregnant women at 24–26 weeks of gestation (n = 166). The concentrations of those molecules were analyzed with clinical parameters related to risk for preterm delivery (PD). In pregnant mice, we evaluated the effect of lipopolysaccharide-induced inflammation and progesterone effect modulation on cervical mRNA expression of SLPI and PGRN. The cervical PGRN level was significantly lower in women with short cervix (<35 mm) and with a history of threatened PD. In women with short cervix, cervical SLPI concentrations were positively correlated with inflammatory cytokines, interleukin-6 (R2 = 0.75) and interleukin-8 (R2 = 0.71). In pregnant mice, cervical mRNA expressions of PGRN and SLPI were increased in response to progesterone supplementation and were suppressed by a progesterone antagonist, mifepristone. Lipopolysaccharide-induced inflammation caused remarkable upregulation in cervical SLPI mRNA level but not in PGRN. Progesterone and local inflammation are the factors controlling expression levels of PGRN and SLPI at the cervix. The observed relationship of PGRN and SLPI levels in the cervical mucus with PD-related clinical parameters supports that those anti-inflammatory molecules possibly play a significant role in appropriate regulation of cervical remodeling.

Airway Microbiota-Host Interactions Regulate Secretory Leukocyte Protease Inhibitor Levels and Influence Allergic Airway Inflammation

SUMMARYHomeostatic mucosal immune responses are fine-tuned by naturally evolved interactions with native microbes, and integrating these relationships into experimental models can provide new insights into human diseases. Here, we leverage a murine-adapted airway microbe, Bordetella pseudohinzii (Bph), to investigate how chronic colonization impacts mucosal immunity and the development of allergic airway inflammation (AAI). Colonization with Bph induces the differentiation of interleukin-17A (IL-17A)-secreting T-helper cells that aid in controlling bacterial abundance. Bph colonization protects from AAI and is associated with increased production of secretory leukocyte protease inhibitor (SLPI), an antimicrobial peptide with anti-inflammatory properties. These findings are additionally supported by clinical data showing that higher levels of upper respiratory SLPI correlate both with greater asthma control and the presence of Haemophilus, a bacterial genus associated with AAI. We propose that SLPI could be used as a biomarker of beneficial host-commensal relationships in the airway.

Concerted actions by MMPs, ADAMTS and serine proteases during remodeling of the cartilage callus into bone during osseointegration of hip implants

IntroductionAlthough the number of patients undergoing total hip arthroplasty is constantly on the rise, we only have limited knowledge of the molecular mechanisms necessary for successful osseointegration of implants or the reasons why some fail. Understanding the spatiotemporal characteristics of signaling pathways involved in bone healing of implants is therefore of particular importance for our ability to identify factors causing implants to fail. The current study investigated the role of three families of proteases, i.e. MMPs (matrix metalloproteinases), ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) and serine proteases, as well as their endogenous inhibitors during osseointegration of hip implants that have endured two decades of use without clinical or radiological signs of loosening. Materials and methodsTwenty-four patients that had undergone primary THA due to one-sided osteoarthritis (OA) were monitored during 18 years (Y) with repeated measurements of plasma biomarkers, clinical variables and radiographs. All implants were clinically and radiographically well-fixed throughout the follow-up. Eighty-one healthy donors divided in three gender and age-matched groups and twenty OA patients awaiting THA, served as controls. Plasma was analyzed for MMP-1, -2, -3, -8, -9, -10, -13, -14, tissue inhibitor of metalloproteinase (TIMP)-1, -2, -3, ADAMTS4, ADAMTS5, the serine proteases neutrophil elastase (NE), proteinase 3 (PR3) and their endogenous inhibitors, secretory leucocyte proteinase inhibitor (SLPI), trappin-2/elafin and serpina1 (α-1 antitrypsin). Cartilage turnover was monitored using two markers of cartilage synthesis, type II procollagen and PIICP (procollagen II C-terminal propeptide), and two markers of cartilage degradation, CTX-II (C-terminal telopeptide fragments of type II collagen) and split products of aggrecan (G1-IGD-G2). ResultsMMP-1, MMP-9, ADAMTS4, NE and PR3 were above healthy in presurgery OA patients but returned to the level of healthy within 6 weeks (W) after surgery. MMPs and serine proteases were counter-regulated during this phase by TIMP-1, SLPI and trappin-2/elafin. Type II procollagen, PIICP and CTX-II increased to a peak 6 W after surgery with a gradual return to the level of controls within weeks. Significant increases by MMP-8, MMP-9, ADAMTS4, ADAMTS5, NE, PR3 and the protease inhibitors, TIMP-3 and serpina1, were seen 5 Y after hip arthroplasty paralleled by a sharp increase in the levels of the cartilage degradation markers, CTX-II and G1-IGD-G2. All the above mediators were normalized before 18 Y, except MMP-1 and MMP-9 that remained above healthy at 18 Y. MMP-14 increased immediately after surgery and remained elevated until 5 Y postsurgery before returning to the level of controls at 7 Y. ConclusionNotwithstanding temporal differences, the molecular processes of bone repair in arthroplasty patients show great spatial similarities with the classical phases of fracture repair as previously shown in animal models. Cartilagenous callus, produced and remodeled early after hip arthroplasty, is replaced with bone 5 Y to7 Y after surgery by the concerted actions of MMP-8, MMP-9, ADAMTS4, ADAMTS5, NE and PR3, thus suggesting that a complex regulatory cross-talk may exist between different families of proteases during this transitional phase of cartilage degradation. Regulation and fine-tuning of cartilage remodeling by MMPs and ADAMTS is controlled by TIMP-3 whereas serine proteases are regulated by serpina1. Increased MMP-1 and MMP-9 beyond 10Y post-THA support a role during coupled bone remodeling.

Recombinant human secretory leukocyte protease inhibitor ameliorated vessel preservation in experimentally isolated rat arteries

Recombinant human secretory leukocyte protease inhibitor ameliorated vessel preservation in experimentally isolated rat arteries

Abstract 353: High Density Lipoprotein Regulates Tumor Necrosis Factor Alpha and Jun Kinase Signaling Pathway in Adipocytes

Background: High-density lipoproteins (HDL) is presumed to exhibit cardiovascular protection, since HDL mediate the reverse transport of cholesterol and exhibit strong anti-inflammatory potential. Previous studies have found that HDL can reduce the level of IL-8 secreted by the inflammatory adipocytes, as well as affect the expression of adiponectin and tumor necrosis factor-alpha (TNF-α) under the inflammatory condition in adipocytes. These studies indicate that HDL is closely related to the inflammatory response of adipose tissue, yet its mechanism has not been fully understood. Secretory leucocyte protease inhibitor (SLPI), a nonglycosylated single-chain polypeptide protein, may play an important role in diet-induced obesity and adipocyte inflammation. Purpose: To study the role of SLPI in HDL anti-inflammatory action in the adipocytes, and explore the mechanism of the action. Methods: 3T3-L1 Adipocytes were induced to differentiation and maturation by culturing. Acute inflammation in adipocytes was induced by LPS (100 ng/ml, 6h), and then the adipocytes were pretreated with HDL and/or SLPI-siRNA. The protein and mRNA levels of SLPI, TNF-α and JNK were examined by Western blotting and qRT-PCR assay, respectively. In addition, the levels of inflammatory factors were measured by ELISA. Results: HDL up-regulated SLPI expression, down-regulated TNF-α expression, and inhibited the secretion of inflammatory factors such as IL-1, IL-6, IL-8 and MCP-1 in 3T3-L1 Adipocytes pre-treated by LPS. Silencing of SLPI by its siRNA effectively abolished the anti-inflammatory effect of HDL. JNK inhibitor (SP600125) partially restored the anti-inflammatory effects of HDL decreased by SLPI knockdown and decreased the secretion of inflammatory factors. Conclusions: These data suggest that HDL up-regulate the expression of SLPI and inhibit the inflammation in 3T3-L1 Adipocytes pre-treated by LPS. The anti-inflammatory effect of HDL, including inhibition of the secretion of inflammatory factors via TNF-α/JNK signaling pathway, probably viat up-regulating the SLPI expression. Key words: high-density lipoprotein, Inflammation, Adipocytes

Neutrophil elastase and endogenous inhibitors in Behçet's disease saliva.

Behçet's disease (BD) is a vasculitis of unknown aetiology typified by chronic recurrent oral ulcers and systemic inflammatory manifestations. Neutrophils, and specifically their protease neutrophil elastase (NE), have been implicated in its pathology. Although NE is an effective anti-microbial, excessive NE can damage host tissue. Recurrent oral ulceration is a primary BD symptom, therefore we hypothesized that excessive neutrophil infiltration evidenced by increased NE and a reduction in specific endogenous inhibitors, secretory leucocyte protease inhibitor (SLPI) and alpha1-anti-trypsin (α1AT) contributes to BD mucosal instability. NE, SLPI and α1AT were quantified in saliva from BD patients with active oral ulcers (BDa) and quiet without ulcers (BDq), recurrent aphthous stomatitis (RASa; RASq) and healthy controls (HC). Although BDq saliva had marginally higher median NE levels (1112ng/ml) compared to both RASq (1043ng/ml) and HC (999ng/ml), SLPI was significantly reduced in BDq (P<0·01). Despite decreased SLPI protein, mRNA expression was significantly increased in BDq buccal epithelial swabs compared to RASq and HC (P<0·05, P<0·001). NE remained enzymatically active, although α1AT levels were at least eight times higher than SLPI in all groups, suggesting that α1AT does not have a primary role in counteracting NE in saliva. Furthermore, NE levels in BDa patients medicated with both azathioprine (AZA) and colchicine (COLC) were significantly lower than those on COLC (P=0·0008) or neither (P=0·02), indicating that combining AZA+COLC may help to regulate excessive NE during ulceration. This study showed that enzymatically active NE coupled with reduced SLPI in BD saliva may contribute to recurrent oral ulcerations.

Targeting secretory leukocyte protease inhibitor (SLPI) inhibits colorectal cancer cell growth, migration and invasion via downregulation of AKT.

The secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor which plays important role in bacterial infection, inflammation, wound healing and epithelial proliferation. Dysregulation of SLPI has been reported in a variety of human cancers including glioblastoma, lung, breast, ovarian and colorectal carcinomas and is associated with tumor aggressiveness and metastatic potential. However, the pathogenic role of SLPI in colorectal cancer is still unclear. Here we showed that SLPI mRNA level was significantly upregulated in colorectal cancer tissues compared to adjacent normal controls. Targeting SLPI by siRNA inhibited proliferation, migration and invasion of colorectal cancer cells lines HT29 and HT116 in vitro. Mechanistically, blockage of cancer cell growth and metastasis after SLPI knockdown was associated with down-regulation of AKT signaling. In conclusion, SLPI regulated colorectal cell growth and metastasis via AKT signaling. SLPI may be a novel biomarker and therapeutic target for colorectal cancer. Targeting AKT signaling may be effective for colorectal cancer treatment.

Evaluation of the levels of secretory leukocyte protease inhibitor in the cervical mucus of women with unexplained infertility.

Secretory leukocyte protease inhibitor (SLPI) has specific effects on the immune system. SLPI is overexpressed in inflammation triggered by immune responses, which could have significant effects on the local immune responses in cervical mucosa. This over expression may be greater in women with unexplained infertility, which would increase the immune reaction in the cervical region against sperm. The aim of our study was to assess the levels of SLPI in cervical mucus in women with unexplained infertility. This prospective cross-sectional study was conducted using 50 Caucasian volunteers between 20 and 40 years old. The 50 participants were divided into two groups as unexplained infertility (n = 20) and control (n = 30). The control group comprised healthy fertile women with demographic characteristics similar to those of the infertility group. The enzyme-linked immunosorbent assay method was used to assess SLPI levels in the cervical mucus of all participants. The median SLPI level in cervical mucus was 3767 (3541-4594, 95% CI) pg/mL (25th percentile; 3139 pg/mL, 75th percentile; 5047 pg/mL) in the unexplained-infertility group and 3204 (2602-3539, 95% CI) pg/mL (the 25th percentile = 2615 pg/mL; 75th percentile = 3990 pg/mL) in the control group, which was a significant difference (P = 0.013). Our results indicated that SLPI levels in cervical mucus were remarkably higher in patients with unexplained infertility than in the control group.

Concomitant Imbalances of Systemic and Mucosal Immunity Increase HIV Acquisition Risk

We previously reported association of increased cervical RANTES and decreased secretory leukocyte protease inhibitor (SLPI) with higher risk of HIV acquisition in reproductive-age women. We now examine the interaction of concomitantly altered systemic and cervical immunity on such risk. We measured immune biomarkers in 4390 cervical and 2390 paired serum specimens at quarterly visits in 218 HIV seroconverters and 784 seronegative women. We assessed proinflammatory (IL-1β, IL-6, IL-8, MIP-3α, and RANTES), anti-inflammatory (IL-1RA and SLPI), vascular activation (vascular endothelial growth factor and Intercellular Adhesion Molecule-1) and defensin (BD2) cervical biomarkers and systemic (peripheral blood) C reactive protein (CRP), IL-6, IL-7, and sCD14 as indicators of immune dysregulation. Biomarker levels were Box-Cox transformed and odds ratios for HIV acquisition calculated based on top quartile or higher/lower than median levels for all HIV-negative visits. Subsequent HIV acquisition was associated with 5 of 14 individual biomarkers: low systemic CRP [odds ratio (OR) = 1.49, 1.21-1.83] and IL-6 (OR = 1.23, 1.00-1.51), high cervical BD-2 (OR = 1.33, 1.11-1.58) and RANTES (OR = 1.20, 1.01-1.43), and low cervical IL-1RA (OR = 0.65, 0.48-0.86). Low systemic CRP concomitant with altered cervical immunity, especially high BD2, conveyed highest HIV risk (1.63, 1.29-2.05). Additional markers of increased risk emerged when low systemic CRP coincided with: low systemic IL-6 and IL-7 (OR = 1.53, 1.18-1.97); high cervical IL-8 and MIP-3α (OR = 1.40, 1.07-1.83); high cervical IL-1β and IL-6 (OR = 1.43, 1.09-1.86); or low cervical SLPI (OR = 1.36, 1.08-1.71). Changes in both peripheral and mucosal immunity may precede and predispose women to HIV infection. Suppressed systemic immunity (ie, low CRP) alone or in combination with imbalanced cervical innate immunity (high proinflammatory and low anti-inflammatory mediators) indicated increased vulnerability to infection. Understanding these combined effects on HIV susceptibility is essential to preventing new infections.

Human serum albumin nanoparticles as nanovector carriers for proteins: Application to the antibacterial proteins "neutrophil elastase" and "secretory leukocyte protease inhibitor".

The use of proteins and defined amino acid sequences as therapeutic drugs have gained a certain interest in the past decade. However, protein encapsulation within protein nanoparticles was never endeavored. For this reason, human serum albumin (HSA) nanoparticles were prepared by nanoprecipitation method. The process was optimized, and particles were obtained with a size of 120nm and zeta potential of -25mV. Neutrophil elastase (NE) and secretory leukocyte protease inhibitor (SLPI) were encapsulated separately within HSA nanoparticles. Gel electrophoresis and western blot studies demonstrate the successful encapsulation and the stability of the particles. On the other hand, enzymatic assays show that encapsulated NE lost its proteolytic activity, whereas encapsulated SLPI maintained its inhibitory property. In addition, the antibacterial studies showed that both formulations were able to drastically reduce bacterial growth of Pseudomonas aeruginosa. This work showed the possibility of using both NE and SLPI as anti-bacterial agents through encapsulation within HSA nanoparticles.

Antibacterial and antiproteinase activities of a double whey acidic protein domain-containing protein from Penaeus vannamei Boone, 1931 (Decapoda, Penaeidae)

Abstract Double whey acidic protein domain-containing proteins (DWDs) or secretory leukocyte protease inhibitor (SLPI)-like proteins, have been identified in many species of Crustacea. The PvDWD1 from Penaeus vannamei was the first SLPI-like protein identified in a crustacean. Herein, we report that the expression of PvDWD1 was up-regulated at 6 h after acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus (VPAHPND) challenge. Similarly, after a different stress other than bacterial infection, the chronic non-lethal heat shock (NLHS) induction, the expression of the PvDWD1 gene was increased at 6 and 24 h after chronic NLHS treatment. The recombinant PvDWD1 (rPvDWD1) protein was over-expressed and tested for its deleterious activity against the bacteria. The rPvDWD1 protein exhibited growth inhibitory activity against Bacillus megaterium and VPAHPND. Moreover, the rPvDWD1 protein possessed an antiproteinase activity against the secreted proteinases from Bacillus subtilis and VPAHPND. The PvDWD1 perhaps functions in shrimp immunity through antimicrobial and antiproteinase properties.

The Inhibition of Inflammatory Signaling Pathway by Secretory Leukocyte Protease Inhibitor can Improve Spinal Cord Injury.

Spinal cord injury leads to loss of sensory motor functions below the damaged area, and can significantly affects physical and mental health. An effective spinal cord injury treatment is currently unavailable, in part, because of the intricacy of the brain, as well as the complex pathophysiological mechanism of the injury. Inflammation is an important biological process in multitudinous diseases, with no exception for spinal cord injury. Nuclear factor kappa beta (NF-κB) signaling pathway is a key inflammatory element, as it is involved in cell survival, apoptosis, proliferation, differentiation, and immune response. Activation of the NF-κB signaling pathway leads to the release of a large number of inflammatory factors that can affect tissue repair. Hence, the inhibition of inflammatory responses could improve the repair of injured spinal cord tissues. Secretory leukocyte protease inhibitor (SLPI) has anti-inflammatory and anti-bacterial properties, and promotes wound healing. SLPI can bind to the promoter region of tumor necrosis factor-αand interleukin-8 (IL-8) to inhibit the NF-κB signaling pathway. Additionally, SLPI can reduce secondary damages after spinal cord injury, and prevent further complications. In this report, we analyze the pathophysiological mechanism of spinal cord injury, the role of NF-κB signaling pathway following spinal cord injury, and how SLPI regulates the NF-κB signaling pathway to curtail inflammatory reaction.

Human immunodeficiency virus type-1 Tat protein induces secretory leukocyte protease inhibitor expression in African green monkey but not human cells.

African monkeys are resistant to HIV-1 infection due to intrinsic restriction mechanisms found in their cells. However, although they can be infected by monkey-adapted modified HIV-1 particles that are designed to overcome known restriction factors, virus numbers drop to undetectable levels in immunocompetent animals. These results indicate the possibility of the presence of yet unidentified factor(s) that restrict HIV-1 in old-world monkey (OWM) cells after integration of the viral genome into the host cell chromosome. In the light of these findings, we hypothesized that OWMs might have evolved resistance mechanism(s) against HIV-1 by switching specific gene(s) on in response to the synthesis of viral proteins in infected cells. In an attempt to mimic post-infection status, we expressed HIV-1 Tat gene in African green monkey cells and compared the whole proteome with normal cells and identified secretory leukocyte protease inhibitor (SLPI), a protein with known extracellular anti-HIV-1 activity, as an over-expressed protein in the presence of HIV-1 Tat protein by 2D-PAGE and mass spectrometry analysis. We also showed that overexpression of SLPI in the presence of HIV-1 Tat was specific to monkey cells. Our results also suggest that SLPI had a previously undiscovered intracellular anti-HIV activity in addition to its extracellular activity.

Expression of the immune modulator secretory leukocyte protease inhibitor (SLPI) in colorectal cancer liver metastases and matched primary tumors is associated with a poorer prognosis

ABSTRACT Secretory leukocyte protease inhibitor (SLPI), a pleiotropic protein expressed by healthy intestinal epithelial cells, functions as an inhibitor of NF-κB and neutrophil proteases and exerts antimicrobial activity. We previously showed SLPI suppresses intestinal epithelial chemokine production in response to microbial contact. Increased SLPI expression was recently detected in various types of carcinoma. In addition, accumulating evidence indicates SLPI expression is favorable for tumor cells. In view of these findings and the abundance of SLPI in the colonic epithelium, we hypothesized SLPI promotes colorectal cancer (CRC) growth and metastasis. Here, we aimed to establish whether SLPI expression in CRC is related to clinical outcome. Using a cohort of 507 patients with CRC who underwent resection of liver metastases, we show that high SLPI protein expression in both liver metastases and primary CRC is associated with significantly shorter overall survival after resection of liver metastases. The prognostic value of SLPI in CRC patients with liver metastases implies a role for SLPI in the formation of metastasis of human CRC. Based on the immune regulatory functions of SLPI, we anticipate that expression of SLPI provides tumors with a mechanism to evade infiltration by immune cells.

Genetic activation of Nrf2 reduces cutaneous symptoms in a murine model of Netherton syndrome.

ABSTRACTNetherton syndrome is a monogenic autosomal recessive disorder primarily characterized by the detachment of the uppermost layer of the epidermis, the stratum corneum. It results from mutations in the SPINK5 gene, which codes for a kallikrein inhibitor. Uncontrolled kallikrein activity leads to premature desquamation, resulting in a severe epidermal barrier defect and subsequent life-threatening systemic infections and chronic cutaneous inflammation. Here, we show that genetic activation of the transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nfe2l2/Nrf2) in keratinocytes of Spink5 knockout mice, a model for Netherton syndrome, significantly alleviates their cutaneous phenotype. Nrf2 activation promoted attachment of the stratum corneum and concomitant epidermal barrier function, and reduced the expression of pro-inflammatory cytokines such as tumor necrosis factor α and thymic stromal lymphopoietin. Mechanistically, we show that Nrf2 activation induces overexpression of secretory leukocyte protease inhibitor (Slpi), a known inhibitor of kallikrein 7 and elastase 2, in mouse and human keratinocytes in vivo and in vitro, respectively. In the Spink5-deficient epidermis, the upregulation of Slpi is likely to promote stabilization of corneodesmosomes, thereby preventing premature desquamation. Our results suggest pharmacological NRF2 activation as a promising treatment modality for Netherton syndrome patients.This article has an associated First Person interview with the first author of the paper.

Relevance of Slpi as Biomarker of Acute Kidney Injury After Open and Endovascular Complex Aortic Surgery

Introduction: Open and endovascular repair of thoracoabdominal aortic aneurysm (TAAA) is related to a relevant rate of postoperative complications such as acute kidney injury (AKI), which is in turn closely linked with poor patients` outcome. Hence an early detection of AKI may enable an immediate start of specific treatment bundles. In this context, the necessity of clinically available early and reliable biomarkers for AKI becomes evident. Secretory leukocyte proteinase inhibitor (SLPI) is a protease inhibitor and regulator of innate and adaptive immunity. It is synthesized predominantly in immune cells and epithelial cells of mucosal surfaces, such as the pancreas and kidney. Patients with AKI showed significantly increased SLPI plasma and urine levels when compared with patients without AKI. The aim of this study was to evaluate SLPI as a potential predictive biomarker of postoperative AKI in patients undergoing complex open and endovascular aortic aneurysm repair. Methods: Between January and December 2017 33 patients have been enrolled in this prospective, non-randomized single-center study. Serum samples were collected at six defined time points until 72 hours after surgery. AKI was defined according to the KDIGO criteria. In a subgroup analysis, patients with preexisting kidney disease (defined as preoperative serum creatinine > 1.2 mg/dl according to the Cleveland clinic foundation score) were excluded. Results: The mean patients' age was 66 ± 16 years. A total of 13 patients (53.3 %) developed postoperative AKI. Serum SLPI showed an early and significant increase within the first 12 hours after surgery until 72 hours after surgery. Patients suffering from AKI showed significantly higher serum SLPI 12 hours after surgery when compared to patients without AKI (p=0.008). The ROC analysis revealed a prognostic accuracy with an Area under Curve [AUC]=0.783 for SLPI as a biomarker of AKI 12 hours after surgery (p=0.009). After exclusion of patients with underlying kidney disease, 20 patients were further analyzed from which 11 patients (55%) showed postoperative AKI. In this group, an even stronger correlation between serum SLPI and AKI was evident: Significantly increased serum SLPI 12, 24, and 48 h after surgery could be observed (12 h: p=0.0002, 24 h: p=0.0016, 48 h: p=0.025). Besides, the respective ROC analysis showed an AUC=0.949 for 12 hours after surgery (p=0.0001), AUC=0.899 for 24 hours after surgery (p=0.0003), and AUC=0.795 for 48h after surgery (p=0.025). Conclusion: The present findings highlight SLPI as a reliable and promising marker for the early detection of postoperative AKI after open and endovascular TAAA repair, Besides, these results potentially suggest a general applicability of SLPI as a biomarker of AKI. Disclosure: Nothing to disclose