Elafin promotes tumour metastasis and attenuates the anti-metastatic effects of erlotinib via binding to EGFR in hepatocellular carcinoma.

BACKGROUND: Elafin is a serine protease inhibitor critical for host defence. We previously reported that Elafin was associated with the recurrence of early-stage hepatocellular carcinoma (HCC) after surgery. However, the exact role of Elafin in HCC remains obscure. METHODS: HCC tissue microarrays were used to investigate the correlation between Elafin expression and the prognosis of HCC patients. In vitro migration, invasion and wound healing assays and in vivo lung metastasis models were used to determine the role of Elafin in HCC metastasis. Mass spectrometry, co-immunoprecipitation, western blotting, and immunofluorescence staining assays were performed to uncover the mechanism of Elafin in HCC. Dual-luciferase reporter and chromatin immunoprecipitation assays were employed to observe the transcriptional regulation of Elafin. RESULTS: Elafin expression was frequently increased in HCC tissues compared to normal tissues, and high Elafin expression in HCC tissues was correlated with aggressive tumour phenotypes and a poor prognosis in HCC patients. Elafin dramatically enhanced the metastasis of HCC cells both in vitro and in vivo by interacting with EGFR and activating EGFR/AKT signalling. Moreover, Elafin attenuated the suppressive effects of erlotinib on HCC metastasis. Besides, Elafin was transcriptionally regulated by Sp1 in HCC cells. Clinically, Elafin expression was positively correlated with Sp1, Vimentin, and EGFR signalling in both our HCC tissue microarrays and TCGA database analysis. CONCLUSIONS: Upregulation of Elafin by Sp1 enhanced HCC metastasis via EGFR/AKT pathway, and overexpression of Elafin attenuated the anti-metastatic effects of erlotinib, suggesting a valuable prognostic biomarker and therapeutic target for HCC.

Elafin inhibits obesity, hyperglycemia, and liver steatosis in high-fat diet-treated male mice.

Elafin is an antimicrobial and anti-inflammatory protein. We hypothesize that elafin expression correlates with diabetes. Among non-diabetic and prediabetic groups, men have significantly higher serum elafin levels than women. Men with type 2 diabetes mellitus (T2DM) have significantly lower serum elafin levels than men without T2DM. Serum elafin levels are inversely correlated with fasting blood glucose and hemoglobin A1c levels in men with T2DM, but not women with T2DM. Lentiviral elafin overexpression inhibited obesity, hyperglycemia, and liver steatosis in high-fat diet (HFD)-treated male mice. Elafin-overexpressing HFD-treated male mice had increased serum leptin levels, and serum exosomal miR181b-5p and miR219-5p expression. Transplantation of splenocytes and serum exosomes from elafin-overexpressing HFD-treated donor mice reduced food consumption and fat mass, and increased adipose tissue leptin mRNA expression in HFD-treated recipient mice. Elafin improved leptin sensitivity via reduced interferon-gamma expression and induced adipose leptin expression via increased miR181b-5p and miR219-5p expression. Subcutaneous and oral administration of modified elafin inhibited obesity, hyperglycemia, and liver steatosis in the HFD-treated mice. Circulating elafin levels are associated with hyperglycemia in men with T2DM. Elafin, via immune-derived miRNAs and cytokine, activates leptin sensitivity and expression that subsequently inhibit food consumption, obesity, hyperglycemia, and liver steatosis in HFD-treated male mice.

The antimicrobial molecule trappin-2/elafin has anti-parasitic properties and is protective in vivo in a murine model of cerebral malaria.

According to the WHO, and despite reduction in mortality rates, there were an estimated 438 000 malaria deaths in 2015. Therefore new antimalarials capable of limiting organ damage are still required. We show that systemic and lung adenovirus (Ad)-mediated over-expression of trappin-2 (T-2) an antibacterial molecule with anti-inflammatory activity, increased mice survival following infection with the cerebral malaria-inducing Plasmodium berghei ANKA (PbANKA) strain. Systemically, T-2 reduced PbANKA sequestration in spleen, lung, liver and brain, associated with a decrease in pro-inflammatory cytokines (eg TNF-α in spleen and lung) and an increase in IL-10 production in the lung. Similarly, local lung instillation of Ad-T-2 resulted in a reduced organ parasite sequestration and a shift towards an anti-inflammatory/repair response, potentially implicating monocytes in the protective phenotype. Relatedly, we demonstrated in vitro that human monocytes incubated with Plasmodium falciparum-infected red blood cells (Pf-iRBCs) and IgGs from hyper-immune African human sera produced T-2 and that the latter colocalized with merozoites and inhibited Pf multiplication. This array of data argues for the first time for the potential therapeutic usefulness of this host defense peptide in human malaria patients, with the aim to limit acute lung injury and respiratory distress syndrom often observed during malaria episodes.

Pharmacological approaches in celiac disease.

Celiac disease is an autoimmune enteropathy triggered by the ingestion of gluten, characterized by immune responses toward gluten constituents and the autoantigen transglutaminase 2. The only current treatment available for celiac disease is a gluten-free diet, however there are a plethora of therapies in development for the treatment of celiac disease (e.g. vaccine), management of symptoms while consuming gluten (e.g. Necator americanus) or adjuvant therapies in conjunction with the gluten-free diet (e.g. larazotide acetate). Current approaches in development target barrier function, immune responses, detoxifying gluten or sequestering gluten. Developing therapies include those targeting environmental factors, such as the microbiota or proteases.

Role of the endogenous elastase inhibitor, elafin, in cardiovascular injury: from epithelium to endothelium.

Neutrophils and neutrophil-derived elastases play a major role in the regulation of vascular injury and inflammation, such as ischemia-reperfusion injury. Elafin is an endogenous inhibitor of neutrophil-derived elastases with numerous anti-inflammatory functions that include modulation of inflammatory cytokine release as well as innate and adaptive immunity. It is produced by epithelial tissues including the skin and respiratory system that have adapted to respond to the microbial and chemical insults that lead to inflammation. The production of peptides like elafin with multi-faceted anti-inflammatory activity is an important part of this adaptation. Although not directly expressed within the cardiovascular system itself, pre-clinical studies have suggested therapeutic benefit of elafin in cardiovascular disease. The aim of this review is to highlight the role of neutrophil-derived elastases in vascular inflammation and injury. We will discuss the beneficial effects of elafin inhibition of neutrophil elastase and its extended anti-inflammatory activity in pre-clinical models of inflammatory vascular injury.

SLPI and trappin-2 as therapeutic agents to target airway serine proteases in inflammatory lung diseases: current and future directions.

It is now clear that NSPs (neutrophil serine proteases), including elastase, Pr3 (proteinase 3) and CatG (cathepsin G) are major pathogenic determinants in chronic inflammatory disorders of the lungs. Two unglycosylated natural protease inhibitors, SLPI (secretory leucocyte protease inhibitor) and elafin, and its precursor trappin-2 that are found in the lungs, have therapeutic potential for reducing the protease-induced inflammatory response. This review examines the multifaceted roles of SLPI and elafin/trappin-2 in the context of their possible use as inhaled drugs for treating chronic lung diseases such as CF (cystic fibrosis) and COPD (chronic obstructive pulmonary disease).

Therapeutic potential of human elafin.

Elafin is an endogenous human protein composed of an N-terminal transglutaminase substrate motif and a C-terminal WAP (whey acidic protein)-domain with antiproteolytic properties. Elafin is expressed predominantly in epithelial tissue and potently inhibits the neutrophil-derived serine proteases elastase and proteinase-3 by a competitive tight-binding mechanism. Furthermore, it inhibits EVE (endogenous vascular elastase). Studies on several animal models show that antiprotease augmentation with human elafin is an effective strategy in the treatment of inflammatory vascular, systemic and pulmonary diseases and of inflammation triggered by reperfusion injury. This raises the possibility that elafin might be effective in the treatment of a variety of human inflammatory diseases. In a Phase I clinical trial, elafin was well tolerated. Phase II trials are underway to investigate the therapeutic effects of elafin on post-operative inflammation and the clinical consequences of major surgery. Of particular interest is the reduction of post-operative morbidity after oesophagus cancer surgery, coronary artery bypass surgery and kidney transplantation.

Burkholderia cenocepacia zinc metalloproteases influence resistance to antimicrobial peptides.

Burkholderia cenocepacia secretes two zinc-dependent metalloproteases, designated ZmpA and ZmpB. Previously, ZmpA and ZmpB have been shown to cleave several proteins important in host defence. In this study, the ability of ZmpA and ZmpB to digest and inactivate antimicrobial peptides involved in innate immunity was examined. ZmpB but not ZmpA cleaved beta-defensin-1. ZmpA but not ZmpB cleaved the cathelicidin LL-37. Both enzymes cleaved elafin and secretory leukocyte inhibitor, which are antimicrobial peptides as well as neutrophil elastase inhibitors. Both ZmpA and ZmpB cleaved protamine, a fish antimicrobial peptide, and a zmpA zmpB mutant was more sensitive to protamine killing than the parental strain. ZmpA or ZmpB cleavage of elafin inactivated its anti-protease activity. The effect of ZmpA and ZmpB on the neutrophil proteases elastase and cathepsin G was also examined but neither enzyme was active against these host proteases. These studies suggest that ZmpA and ZmpB may influence the resistance of B. cenocepacia to host antimicrobial peptides as well as alter the host protease/anti-protease balance in chronic respiratory infections.

Human neutrophil elastase: mediator and therapeutic target in atherosclerosis.

Human neutrophil elastase (HNE) is present within atherosclerotic plaques where it contributes to matrix degradation and weakening of the vessel wall associated with the complications of aneurysm formation and plaque rupture. It is joined by other extracellular proteases in these actions but the broad range of substrates and potency of HNE coupled with the potential for rapid increases in HNE activity associated with neutrophil degranulation in acute coronary syndromes single this disruptive protease out as therapeutic target in atherosclerotic disease. This review summarises the role of HNE in neutrophil-mediated endothelial injury and the evidence for HNE as a mediator of atherosclerotic plaque development. The therapeutic potential of HNE neutralising antiproteases, alpha-1-antitrypsin and elafin, in atherosclerosis, is discussed.