A human surfactant peptide-elastase inhibitor construct as a treatment for emphysema

Nanozymes as Enzyme Inhibitors

Nanozyme is a type of nanomaterial with intrinsic enzyme-like activity. Following the discovery of nanozymes in 2007, nanozyme technology has become an emerging field bridging nanotechnology and biology, attracting research from multi-disciplinary areas focused on the design and synthesis of catalytically active nanozymes. However, various types of enzymes can be mimicked by nanomaterials, and our current understanding of nanozymes as enzyme inhibitors is limited. Here, we provide a brief overview of the utility of nanozymes as inhibitors of enzymes, such as R-chymotrypsin (ChT), β-galactosidase (β-Gal), β-lactamase, and mitochondrial F0F1-ATPase, and the mechanisms underlying inhibitory activity. The advantages, challenges and future research directions of nanozymes as enzyme inhibitors for biomedical research are further discussed.

Natural Derived Surfactant Preparation As a Carrier of Polymyxin E for Treatment of Pseudomonas aeruginosa Pneumonia in a Near-Term Rabbit Model

BACKGROUND

Pulmonary surfactant spreads rapidly over the airway epithelium, a property that could be harnessed to transport drugs into the lungs. For efficient drug delivery, an interaction between pulmonary surfactant and the drug to be administered is likely needed. On the other hand, the interaction should not compromise the activity of surfactant or the drug once delivered in vivo. The antibiotics gentamicin (an aminoglycoside) and polymyxin E represent drugs that could benefit from being delivered directly to the lung, thereby increasing local concentrations and reducing systemic side effects. Our aim was to study how the animal-derived surfactant poractant alfa (Curosurf^®) affects the activities of polymyxin E and gentamicin against Pseudomonas aeruginosa.

METHODS

In vitro antimicrobial assays and a neonatal near-term rabbit model were used to evaluate the combinations of antibiotics and surfactant against Pseudomonas aeruginosa.

RESULTS

The bactericidal activity of polymyxin E, but not of gentamicin, against P. aeruginosa was partly reduced in vitro in the presence of poractant alfa. In contrast, in the rabbit model of P. aeruginosa pneumonia, polymyxin E administrated together with surfactant was superior in lowering the bacterial load in the lungs compared to polymyxin E alone, without affecting plethysmographically recorded lung compliance.

CONCLUSIONS

The results suggest that polymyxin E interacts with poractant alfa, which reduces the antibacterial effect in vitro. However, when polymyxin E mixed with surfactant is used in the in vivo pneumonia model, increased bactericidal effect was observed. This may be due to a more efficient spreading mediated by interactions between polymyxin E and surfactant. These results warrant further studies of surfactant preparations for drug delivery against lung infections.

Hot-spot identification on a broad class of proteins and RNA suggest unifying principles of molecular recognition

Chemically diverse fragments tend to collectively bind at localized sites on proteins, which is a cornerstone of fragment-based techniques. A central question is how general are these strategies for predicting a wide variety of molecular interactions such as small molecule-protein, protein-protein and protein-nucleic acid for both experimental and computational methods. To address this issue, we recently proposed three governing principles, (1) accurate prediction of fragment-macromolecule binding free energy, (2) accurate prediction of water-macromolecule binding free energy, and (3) locating sites on a macromolecule that have high affinity for a diversity of fragments and low affinity for water. To test the generality of these concepts we used the computational technique of Simulated Annealing of Chemical Potential to design one small fragment to break the RecA-RecA protein-protein interaction and three fragments that inhibit peptide-deformylase via water-mediated multi-body interactions. Experiments confirm the predictions that 6-hydroxydopamine potently inhibits RecA and that PDF inhibition quantitatively tracks the water-mediated binding predictions. Additionally, the principles correctly predict the essential bound waters in HIV Protease, the surprisingly extensive binding site of elastase, the pinpoint location of electron transfer in dihydrofolate reductase, the HIV TAT-TAR protein-RNA interactions, and the MDM2-MDM4 differential binding to p53. The experimental confirmations of highly non-obvious predictions combined with the precise characterization of a broad range of known phenomena lend strong support to the generality of fragment-based methods for characterizing molecular recognition.

Bone marrow stem cell therapy partially ameliorates pathological consequences in livers of mice expressing mutant human α1-antitrypsin

Alpha-1-antitrypsin (AAT) deficiency (AATD) is a genetic disease, caused by mutation of the AAT gene. Accumulation of mutated AAT protein aggregates in hepatocytes leads to endoplasmic reticulum stress, resulting in impairment of liver functions and, in some cases, hepatocellular carcinoma, whereas decline of AAT levels in sera is responsible for pulmonary emphysema. In advanced liver disease, the only option for treatment is liver transplantation, whereas AAT replacement therapy is therapeutic for emphysema. Given that hepatocytes are the primary affected cells in AATD, we investigated whether transplantation of bone marrow (BM)-derived stem cells in transgenic mice expressing human AATZ (the Z variant of AAT) confers any competitive advantages compared to host cells that could lead to pathological improvement. Mouse BM progenitors and human mesenchymal stem cells (MSCs) appeared to contribute in replacement of 40% and 13% host hepatocytes, respectively. Transplantation of cells resulted in decline of globule-containing hepatocytes, improvement in proliferation of globule-devoid hepatocytes from the host-derived hepatocytes, and apparently, donor-derived cells. Further analyses revealed that transplantation partially improves liver pathology as reflected by inflammatory response, fibrosis, and apoptotic death of hepatocytes. Cell therapy was also found to improve liver glycogen storage and sera glucose level in mice expressing human AATZ mice. These overall improvements in liver pathology were not restricted to transplantation of mouse BM cells. Preliminary results also showed that following transplantation of human BM-derived MSCs, globule-containing hepatocytes declined and donor-derived cells expressed human AAT protein.

CONCLUSION

These results suggest that BM stem cell transplantation may be a promising therapy for AATD-related liver disease. (Hepatology 2017;65:1319-1335).

Plant Proteinase Inhibitor BbCI Modulates Lung Inflammatory Responses and Mechanic and Remodeling Alterations Induced by Elastase in Mice

Background. Proteinases play a key role in emphysema. Bauhinia bauhinioides cruzipain inhibitor (BbCI) is a serine-cysteine proteinase inhibitor. We evaluated BbCI treatment in elastase-induced pulmonary alterations. Methods.  C57BL/6 mice received intratracheal elastase (ELA group) or saline (SAL group). One group of mice was treated with BbCI (days 1, 15, and 21 after elastase instillation, ELABC group). Controls received saline and BbCI (SALBC group). After 28 days, we evaluated respiratory mechanics, exhaled nitric oxide, and bronchoalveolar lavage fluid. In lung tissue we measured airspace enlargement, quantified neutrophils, TNFα-, MMP-9-, MMP-12-, TIMP-1-, iNOS-, and eNOS-positive cells, 8-iso-PGF2α, collagen, and elastic fibers in alveolar septa and airways. MUC-5-positive cells were quantified only in airways. Results. BbCI reduced elastase-induced changes in pulmonary mechanics, airspace enlargement and elastase-induced increases in total cells, and neutrophils in BALF. BbCI reduced macrophages and neutrophils positive cells in alveolar septa and neutrophils and TNFα-positive cells in airways. BbCI attenuated elastic and collagen fibers, MMP-9- and MMP-12-positive cells, and isoprostane and iNOS-positive cells in alveolar septa and airways. BbCI reduced MUC5ac-positive cells in airways. Conclusions. BbCI improved lung mechanics and reduced lung inflammation and airspace enlargement and increased oxidative stress levels induced by elastase. BbCI may have therapeutic potential in chronic obstructive pulmonary disease.

A Plant Proteinase Inhibitor from Enterolobium contortisiliquum Attenuates Pulmonary Mechanics, Inflammation and Remodeling Induced by Elastase in Mice

Proteinase inhibitors have been associated with anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment for emphysema. Our aim was to evaluate the effects of a plant Kunitz proteinase inhibitor, Enterolobium contortisiliquum trypsin inhibitor (EcTI), on several aspects of experimental elastase-induced pulmonary inflammation in mice. C57/Bl6 mice were intratracheally administered elastase (ELA) or saline (SAL) and were treated intraperitoneally with EcTI (ELA-EcTI, SAL-EcTI) on days 1, 14 and 21. On day 28, pulmonary mechanics, exhaled nitric oxide (ENO) and number leucocytes in the bronchoalveolar lavage fluid (BALF) were evaluated. Subsequently, lung immunohistochemical staining was submitted to morphometry. EcTI treatment reduced responses of the mechanical respiratory system, number of cells in the BALF, and reduced tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-12 (MMP-12), tissue inhibitor of matrix metalloproteinase (TIMP-1), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS)-positive cells and volume proportion of isoprostane, collagen and elastic fibers in the airways and alveolar walls compared with the ELA group. EcTI treatment reduced elastase induced pulmonary inflammation, remodeling, oxidative stress and mechanical alterations, suggesting that this inhibitor may be a potential therapeutic tool for chronic obstructive pulmonary disease (COPD) management.

Human neutrophil elastase degrades SPLUNC1 and impairs airway epithelial defense against bacteria

Background

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are a significant cause of mortality of COPD patients, and pose a huge burden on healthcare. One of the major causes of AECOPD is airway bacterial (e.g. nontypeable Haemophilus influenzae [NTHi]) infection. However, the mechanisms underlying bacterial infections during AECOPD remain poorly understood. As neutrophilic inflammation including increased release of human neutrophil elastase (HNE) is a salient feature of AECOPD, we hypothesized that HNE impairs airway epithelial defense against NTHi by degrading airway epithelial host defense proteins such as short palate, lung, and nasal epithelium clone 1 (SPLUNC1).

Methodology/Main Results

Recombinant human SPLUNC1 protein was incubated with HNE to confirm SPLUNC1 degradation by HNE. To determine if HNE-mediated impairment of host defense against NTHi was SPLUNC1-dependent, SPLUNC1 protein was added to HNE-treated primary normal human airway epithelial cells. The in vivo function of SPLUNC1 in NTHi defense was investigated by infecting SPLUNC1 knockout and wild-type mice intranasally with NTHi. We found that: (1) HNE directly increased NTHi load in human airway epithelial cells; (2) HNE degraded human SPLUNC1 protein; (3) Recombinant SPLUNC1 protein reduced NTHi levels in HNE-treated human airway epithelial cells; (4) NTHi levels in lungs of SPLUNC1 knockout mice were increased compared to wild-type mice; and (5) SPLUNC1 was reduced in lungs of COPD patients.

Conclusions

Our findings suggest that SPLUNC1 degradation by neutrophil elastase may increase airway susceptibility to bacterial infections. SPLUNC1 therapy likely attenuates bacterial infections during AECOPD.

The role of autophagy in host defence against Mycobacterium tuberculosis infection

Autophagy is a vital homeostatic process triggered by starvation and other cellular stresses, in which cytoplasmatic cargo is targeted for degradation in specialized structures termed autophagosomes. Autophagy is involved in nutrient regeneration, protein and organelle degradation, but also in clearance of intracellular pathogens such as Mycobacterium tuberculosis, the causative agent of tuberculosis. Recent studies suggest that induction of autophagy in macrophages is an effective mechanism to enhance intracellular killing of M. tuberculosis, and that the ability of the pathogen to inhibit this process is of paramount importance for its survival. Patient studies have shown genetic associations between tuberculosis and the autophagy gene IRGM, as well as with several genes indirectly involved in autophagy. In this review we will discuss the complex interplay between M. tuberculosis and autophagy, as well as the effect of polymorphisms in autophagy-related genes on susceptibility to tuberculosis.

Neutrophil elastase inhibitors

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) constitutes a worldwide health problem. There is currently an urgent and unmet need for the development of small molecule therapeutics capable of blocking and/or reversing the progression of the disorder. Recent studies have greatly illuminated our understanding of the multiple pathogenic processes associated with COPD. Of paramount importance is the key role played by proteases, oxidative stress, apoptosis and inflammation. Insights gained from these studies have made possible the exploration of new therapeutic approaches.

AREAS COVERED

An overview of major developments in COPD research with emphasis on low-molecular mass neutrophil elastase inhibitors is described in this review.

EXPERT OPINION

Great strides have been made toward our understanding of the biochemical and cellular events associated with COPD. However, our knowledge regarding the inter-relationships among the multiple pathogenic mechanisms and their mediators involved is still limited. The problem is further compounded by the unavailability of suitable validated biomarkers for assessing the efficacy of potential therapeutic interventions. The complexity of COPD suggests that effective therapeutic interventions may require the administration of more than one agent such as a human neutrophil elastase or MMP-12 inhibitor with an anti-inflammatory agent such as a PDE4 inhibitor or a dual function agent capable of disrupting the cycle of proteolysis, apoptosis, inflammation and oxidative stress.

Emerging drugs for alpha-1-antitrypsin deficiency

IMPORTANCE OF THE FIELD

Alpha-1-antitrypsin (A1AT) deficiency is a common genetic condition that predisposes individuals to the development of chronic obstructive pulmonary disease (COPD) as a direct result of damage caused to the lung by proteolytic enzymes released by migrating neutrophils. The lack of A1AT fails to control these enzymes and in the most common genetic deficiency (Pi Z) is due to accumulation of A1AT in the liver as a result of polymer formation. There is no specific treatment for COPD but understanding the pathophysiology of the disease in A1AT deficiency has led to strategies being used or developed to prevent the lung and liver disease. These strategies may have benefits beyond A1AT deficiency.

AREAS COVERED IN THIS REVIEW

The review covers the history of discovery of the nature and role of A1AT deficiency with particular emphasis on the pathophysiology of the lung disease. Evidence for the role of current therapies is provided together with data of preliminary or experimental strategies that are under development.

WHAT THE READER WILL GAIN

The reader will gain insight into the role of proteinases in the pathophysiology of COPD with particular reference to A1AT deficiency, which is the only human model of the disease. Current evidence of the efficacy of augmentation is provided together with new ways of readdressing the balance between neutrophil proteinases and natural or synthetic inhibitors or repairing lung damage.

TAKE HOME MESSAGE

A1AT deficiency is a good model to investigate the role of inflammation and proteolytic enzymes in the pathophysiology of COPD. Augmentation therapy is expensive but restores the deficiency to normal and current evidence suggests this ameliorates progression of the disease. Understanding the mechanisms involved has led to the development of newer strategies to protect the lung and liver from the development of disease but efficacy and safety concerns require careful introduction of these strategies. Although the condition is relatively common in the Northern hemisphere, the ability to deliver conventional Phase III clinical trials with lung physiology as the primary outcome will be limited by the sensitivity of the tests and number of patients required.