EFFECTS OF ELASTASE INHIBITOR ON THE EPITHELIAL CELL APOPTOSIS IN BLEOMYCIN-INDUCED PULMONARY FIBROSIS

Recombinant Deoxyribonuclease I Eye Drops for Ocular Graft Versus Host Disease: Results of a Randomized Clinical Trial

OBJECTIVE

We have previously shown that neutrophil extracellular traps (NETs) are present on the ocular surface of patients with ocular graft versus host disease (oGVHD), contributing to inflammation and surface disease. Therefore, we performed a clinical trial using deoxyribonuclease I (DNAase) eye drops to test the hypothesis that reducing the abundance of NETs from the ocular surface will reduce signs and symptoms of oGVHD.

METHODS

A prospective, phase I or II, randomized, placebo-controlled, double-masked clinical trial was performed to determine the safety and preliminary efficacy of DNAase (0.1%) eye drops four times daily for 8 weeks in patients with oGVHD (n=58). Intent-to-treat analysis was performed to determine the change in safety outcome measures (drug tolerability and proportion of adverse events) and efficacy outcome measures (ocular surface disease index [OSDI] score and corneal staining) between baseline and week 8.

RESULTS

Tolerability and adverse events were similar in the vehicle and DNAase groups. Within the DNAase group (but not the vehicle group), corneal staining showed a statistically significant and clinically meaningful reduction at week 8 (3.50 [2.75; 5.00]) compared with baseline (5.00 [3.00; 7.00]). The OSDI score also showed a statistically significant clinically meaningful reduction of 18.4 (9.16; 33.1) ( P <0.001) at week 8 compared with baseline (45.5 [31.8; 50.0]) within the DNAase group. The proportion of eyes that had improvement in subjective global assessment (SGA) and mucous discharge was significantly greater in the DNAase group (55.6% and 57.7% at weeks 4 and 8, respectively; P <0.0001 at both time points) as compared with the vehicle group (35.7% and 34.0% at weeks 4 and 8, respectively).

CONCLUSIONS

Treatment of patients with oGVHD using DNAase eye drops is safe and demonstrates preliminary efficacy. Deoxyribonuclease I eye drops can potentially reduce the severity of signs and symptoms of ocular surface disease in patients with oGVHD.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

Melatonin attenuates lipopolysaccharide-induced immune dysfunction in dendritic cells

Melatonin, a ubiquitous hormone, is principally secreted from pineal gland in mammals and possesses strong antioxidant and anti-inflammatory properties. However, its specific roles in the immune functions of dendritic cells (DCs) during acute lung injury (ALI) remain unknown. In this study, we found that melatonin restored the body weight, decreased the lung weight/body weight ratio, alleviated the histopathological lung injury, and decreased the levels of cytokines (tumor necrosis factor-α (TNF-α), interleukin (IL)-12p70, IL-17, and IL-10) in bronchoalveolar lavage fluid of the lipopolysaccharide (LPS)-induced ALI murine model. Moreover, melatonin inhibited the major histocompatibility complex II (MHCII) expression of lung CD11b⁺ DCs after LPS challenge in vivo. In vitro, melatonin reversed the shape index, promoted the endocytosis, and inhibited phenotypic expression of MHCII, CD40, CD80, and CD86 in LPS-activated DCs. Furthermore, melatonin decreased the expression of an activated marker, CD69, and the secretion of pro-inflammatory cytokines (TNF-α, IL-12p70, and IL-17) after LPS challenge. It hampered the LPS-activated DCs migration by downregulating the C-C chemokine receptor 7 (CCR7) expression, and then weakened the ability of LPS-induced DCs to stimulate allogeneic CD4⁺ T cell proliferation. Melatonin shaped the immune function of DCs in a nuclear factor erythroid-2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) axis-dependent manner. These findings indicate that melatonin protects DCs from ALI-induced immunological stress and may be used to develop novel DC-targeting strategies for ALI therapy.

The In Vitro Inhibitory Effect of Sivelestat on Elastase Induced Collagen and Metallopeptidase Expression in Equine Endometrium

Neutrophil extracellular traps (NETs) fight endometritis, and elastase (ELA), a protease found in NETs, might induce collagen type I (COL1) accumulation in equine endometrium. Metallopeptidases (MMPs) are involved in extracellular matrix balance. The aim was to evaluate the effects of ELA and sivelestat (selective elastase inhibitor) on MMP-2 and MMP-9 expression and gelatinolytic activity, as well as the potential inhibitory effect of sivelestat on ELA-induced COL1 in equine endometrium. Endometrial explants from follicular (FP) and mid-luteal (MLP) phases were treated for 24 or 48 h with ELA, sivelestat, and their combination. Transcripts of COL1A2, MMP2, and MMP9 were evaluated by qPCR; COL1 protein relative abundance by Western blot, and MMP-2 and MMP-9 gelatinolytic activity by zymography. In response to ELA treatment, there was an increase in MMP2 mRNA transcription (24 h) in active MMP-2 (48 h), both in FP, and in MMP9 transcripts in FP (48 h) and MLP (24 h) (p < 0.05). Sivelestat inhibited ELA-induced COL1A2 transcripts in FP (24 h) and MLP (24 h, 48 h) (p < 0.05). The sivelestat inhibitory effect was detected in MMP9 transcripts in FP at 48 h (p < 0.05), but proteases activity was unchanged. Thus, MMP-2 and MMP-9 might be implicated in endometrium fibrotic response to ELA. In mare endometrium, sivelestat may decrease ELA-induced COL1 deposition and hinder endometrosis development.

A Phase I/II Placebo-Controlled Randomized Pilot Clinical Trial of Recombinant Deoxyribonuclease (DNase) Eye Drops Use in Patients With Dry Eye Disease

Purpose

To determine whether DNase eye drops have the potential to reduce signs and symptoms of dry eye disease (DED).

Methods

A placebo-controlled, randomized clinical trial was performed to compare the safety and efficacy of DNase eye drops 0.1% four times a day for 8 weeks in patients with severe tear deficient DED. The change in safety outcome measures (drug tolerability and proportion of adverse events) and efficacy outcome measures (Ocular Surface Disease Index [OSDI] score, corneal and conjunctival staining) were analyzed between baseline and week 8.

Results

Tolerability and adverse events were similar in placebo group and DNase group. Within the DNase group (but not placebo group), corneal staining showed a statistically significant and clinically meaningful reduction at week 8 compared with baseline. The OSDI score also showed a significant median reduction of 27.3 at week 8 compared with baseline within the DNase group. The median reduction in corneal staining and mucoid debris/strands was significantly greater in the DNase group as compared with the placebo group. In the DNase group, the median reduction in OSDI (-20.75) was more than placebo group (-8.43); however, the difference between groups was borderline significant.

Conclusions

In this pilot study, treatment of severe tear deficient DED patients with DNase eye drops appears safe, well tolerated, and has the potential to reduce the severity of signs and symptoms.

Translational Relevance

Data from this pilot clinical trial demonstrate the therapeutic potential of DNase eye drops in dry eye disease, possibly due to degradation neutrophil extracellular traps (NETs) from the ocular surface.

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.

Alpha-1 Antitrypsin Mitigates the Inhibition of Airway Epithelial Cell Repair by Neutrophil Elastase

Neutrophil elastase (NE) activity is associated with many destructive lung diseases and is a predictor for structural lung damage in early cystic fibrosis (CF), which suggests normal maintenance of airway epithelium is prevented by uninhibited NE. However, limited data exist on how the NE activity in airways of very young children with CF affects function of the epithelia. The aim of this study was to determine if NE activity could inhibit epithelial homeostasis and repair and whether any functional effect was reversible by antiprotease alpha-1 antitrypsin (α1AT) treatment. Viability, inflammation, apoptosis, and proliferation were assessed in healthy non-CF and CF pediatric primary airway epithelial cells (pAECnon-CF and pAECCF, respectively) during exposure to physiologically relevant NE. The effect of NE activity on pAECCF wound repair was also assessed. We report that viability after 48 hours was significantly decreased by 100 nM NE in pAECnon-CF and pAECCF owing to rapid cellular detachment that was accompanied by inflammatory cytokine release. Furthermore, both phenotypes initiated an apoptotic response to 100 nM NE, whereas ≥ 50 nM NE activity significantly inhibited the proliferative capacity of cultures. Similar concentrations of NE also significantly inhibited wound repair of pAECCF, but this effect was reversed by the addition of α1AT. Collectively, our results demonstrate free NE activity is deleterious for epithelial homeostasis and support the hypothesis that proteases in the airway contribute directly to CF structural lung disease. Our results also highlight the need to investigate antiprotease therapies in early CF disease in more detail.

CD8+ T Cell Response to Gammaherpesvirus Infection Mediates Inflammation and Fibrosis in Interferon Gamma Receptor-Deficient Mice

Idiopathic pulmonary fibrosis (IPF), one of the most severe interstitial lung diseases, is a progressive fibrotic disorder of unknown etiology. However, there is growing appreciation for the role of viral infection in disease induction and/or progression. A small animal model of multi-organ fibrosis, which involves murine gammaherpesvirus (MHV68) infection of interferon gamma receptor deficient (IFNγR-/-) mice, has been utilized to model the association of gammaherpesvirus infections and lung fibrosis. Notably, several MHV68 mutants which fail to induce fibrosis have been identified. Our current study aimed to better define the role of the unique MHV68 gene, M1, in development of pulmonary fibrosis. We have previously shown that the M1 gene encodes a secreted protein which possesses superantigen-like function to drive the expansion and activation of Vβ4+ CD8+ T cells. Here we show that M1-dependent fibrosis is correlated with heightened levels of inflammation in the lung. We observe an M1-dependent cellular infiltrate of innate immune cells with most striking differences at 28 days-post infection. Furthermore, in the absence of M1 protein expression we observed reduced CD8+ T cells and MHV68 epitope specific CD8+ T cells to the lungs-despite equivalent levels of viral replication between M1 null and wild type MHV68. Notably, backcrossing the IFNγR-/- onto the Balb/c background, which has previously been shown to exhibit weak MHV68-driven Vβ4+ CD8+ T cell expansion, eliminated MHV68-induced fibrosis-further implicating the activated Vβ4+ CD8+ T cell population in the induction of fibrosis. We further addressed the role that CD8+ T cells play in the induction of fibrosis by depleting CD8+ T cells, which protected the mice from fibrotic disease. Taken together these findings are consistent with the hypothesized role of Vβ4+ CD8+ T cells as mediators of fibrotic disease in IFNγR-/- mice.

Neutrophil elastase induces inflammation and pain in mouse knee joints via activation of proteinase-activated receptor-2

BACKGROUND AND PURPOSE

Neutrophil elastase plays a crucial role in arthritis. Here, its potential in triggering joint inflammation and pain was assessed, and whether these effects were mediated by proteinase-activated receptor-2 (PAR2).

EXPERIMENTAL APPROACH

Neutrophil elastase (5 μg) was injected into the knee joints of mice and changes in blood perfusion, leukocyte kinetics and paw withdrawal threshold were assessed. Similar experiments were performed in animals pretreated with the neutrophil elastase inhibitor sivelestat, the PAR2 antagonist GB83, the p44/42 MAPK inhibitor U0126 and in PAR2 receptor knockout (KO) mice. Neutrophil elastase activity was also evaluated in arthritic joints by fluorescent imaging and sivelestat was assessed for anti-inflammatory and analgesic properties.

KEY RESULTS

Intra-articular injection of neutrophil elastase caused an increase in blood perfusion, leukocyte kinetics and a decrease in paw withdrawal threshold. Sivelestat treatment suppressed this effect. The PAR2 antagonist GB83 reversed neutrophil elastase-induced synovitis and pain and these responses were also attenuated in PAR2 KO mice. The MAPK inhibitor U0126 also blocked neutrophil elastase-induced inflammation and pain. Active neutrophil elastase was increased in acutely inflamed knees as shown by an activatable fluorescent probe. Sivelestat appeared to reduce neutrophil elastase activity, but had only a moderate anti-inflammatory effect in this model.

CONCLUSIONS AND IMPLICATIONS

Neutrophil elastase induced acute inflammation and pain in knee joints of mice. These changes are PAR2-dependent and appear to involve activation of a p44/42 MAPK pathway. Blocking neutrophil elastase, PAR2 and p44/42 MAPK activity can reduce inflammation and pain, suggesting their utility as therapeutic targets.

The Ability of Secretory Leukocyte Protease Inhibitor to Inhibit Apoptosis in Monocytes Is Independent of Its Antiprotease Activity

Secretory Leukocyte Protease Inhibitor (SLPI) is a serine protease inhibitor produced by epithelial and myeloid cells with anti-inflammatory properties. Research has shown that SLPI exerts its anti-inflammatory activity by directly binding to NF-κB DNA binding sites and, in so doing, prevents binding and subsequent transcription of proinflammatory gene expression. In the current study, we demonstrate that SLPI can inhibit TNF-α-induced apoptosis in U937 cells and peripheral blood monocytes. Specifically, SLPI inhibits TNF-α-induced caspase-3 activation and DNA degradation associated with apoptosis. We go on to show that this ability of SLPI to inhibit apoptosis is not dependent on its antiprotease activity as antiprotease deficient variants of SLPI can also inhibit TNF-α-induced apoptosis. This reduction in monocyte apoptosis may preserve monocyte function during inflammation resolution and promote infection clearance at mucosal sites.

Effects of sivelestat treatment on acute lung injury in paraquat-intoxicated rats

Lung injury is the main cause of death in acute paraquat (PQ) intoxication. Sivelestat (SV), a neutrophil elastase inhibitor, is effective in reducing inflammation in acute lung injury. The aim of this study was to examine the effect of SV on acute lung injury in PQ-intoxicated rats. Seven-week-old male Sprague-Dawley rats were randomly assigned to four groups: (1) control group (group N; n = 5); (2) PQ + normal saline (group P; n = 6); (3) normal saline + SV (group S; n = 6) and (4) PQ + SV (group PS; n = 6). SV treatment (intraperitoneally [i.p.], 20 mg/kg) was performed 30 minutes after PQ injection (i.p., 100 mg/kg), and injections were continued every hour for a total of five doses. One hour after the last treatment, blood samples were obtained for analysis of interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α). Lung sections were stained with hematoxylin--eosin for light microscopic analysis. Neutrophil infiltration score of group PS was significantly lower than that of group P (p < 0.05). But, other scores and total score had no significant differences. IL-6 of group PS did not differ, compared to group P. In addition, there were no differences among the four groups. TNF-α of group PS was reduced, in comparison to the level of group P. SV attenuated neutrophil infiltration in PQ-induced acute lung injury in rats. In addition, systemic inflammation was partially suppressed with SV treatment, suppressing TNF-α production. These results suggest that SV reduces paraquat-induced lung injury, at least partially, by inhibiting neutrophil infiltration and TNF-α secretion.

Ocular surface extracellular DNA and nuclease activity imbalance: a new paradigm for inflammation in dry eye disease

PURPOSE

We determined whether nucleases are deficient in the tear fluid of dry eye disease (DED) patients, and whether this causes extracellular DNA (eDNA) and neutrophil extracellular trap (NET) accumulation in the precorneal tear film, thus causing ocular surface inflammation.

METHODS

Exfoliated cells adhered to Schirmer test strips were collected on glass slides, and immunofluorescence confocal microscopy was used to evaluate neutrophils, eDNA, NETs, and their molecular components. Similar experiments were performed with mucoid films collected from the inferior conjunctival fornix or bulbar conjunctiva. We used quantitative PCR to evaluate eDNA signaling pathways and inflammatory cytokine expression. We also determined the amount of ocular surface eDNA and evaluated tear fluid nuclease activity.

RESULTS

eDNA, NETs, and neutrophils were present on the ocular surface in DED patients and abundant in mucoid films. NETs consisted of eDNA, histones, cathelicidin, and neutrophil elastase. Tear fluid nuclease activity was decreased significantly in DED patients, whereas the amount of eDNA on the ocular surface was increased significantly. Expression of genes downstream of eDNA signaling, such as TLR9, MyD88, and type I interferon, as well as the inflammatory cytokines interleukin-6 and tumor necrosis factor-α, was significantly increased in DED patients.

CONCLUSIONS

Extracellular DNA production and clearance mechanisms are dysregulated in DED. Nuclease deficiency in tear fluid allows eDNA and NETs to accumulate in precorneal tear film, and results in ocular surface inflammation. These findings point to novel therapeutic interventions in severe DED based on clearance of eDNA, NETs, and other molecular components from the ocular surface.

CXC receptor 1 and 2 and neutrophil elastase inhibitors alter radiation-induced lung disease in the mouse

PURPOSE

We previously reported increased numbers of neutrophils to be associated with the development of the radiation-induced lung responses of alveolitis (pneumonitis) and fibrosis in mice. In the present study we investigated whether CXC receptor 1 and 2 antagonism with DF2156A, a small molecule inhibitor of neutrophil chemotaxis, or the neutrophil elastase inhibitor sivelestat decreases the lung response to irradiation.

METHODS AND MATERIALS

KK/HIJ mice received 14 Gy whole-thorax irradiation, and a subset of them received drug treatment 3 times per week from the day of irradiation until they were killed because of respiratory distress symptoms.

RESULTS

Irradiated mice receiving sivelestat survived 18% longer than did mice receiving radiation alone (73 vs 60 days for female mice, 91 vs 79 days for male mice), whereas postirradiation survival times did not differ between the group of mice receiving DF2156A and the radiation-only group. The numbers of neutrophils in lung tissue and in bronchoalveolar lavage fluid did not differ among groups of irradiated mice, but they significantly exceeded the levels in unirradiated control mice. The extent of alveolitis, assessed histologically, did not differ between irradiated mice treated with either drug and those receiving radiation alone, when assessed at the end of the experiment, but it was significantly reduced, as were the neutrophil measures, in sivelestat-treated mice at the common kill time of 60 days after irradiation. Mice treated with radiation and DF2156A developed significantly less fibrosis than did mice receiving radiation alone, and this difference was associated with decreased expression of interleukin-13 in lung tissue.

CONCLUSIONS

We conclude that neutrophil elastase inhibition affects alveolitis and prolongs survival, whereas CXCR1/2 antagonism reduces radiation-induced fibrotic lung disease in mice without affecting the onset of distress.

Administration of a specific inhibitor of neutrophil elastase attenuates pulmonary fibrosis after acute lung injury in mice

Excess production of neutrophil elastase contributes to the pathogenesis of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, the role of neutrophil elastase in the repair process following ALI/ARDS is not well understood. The objective of this study was to evaluate the effect of neutrophil elastase on the process of tissue repair after acute lung injury in mice. C57BL/6 mice were exposed to sublethal irradiation followed by intranasal instillation of lipopolysaccharide (LPS) to generate a model of impaired lung repair. The authors assessed the histopathology, lung mechanics, and total lung collagen content 7 days after irradiation and/or LPS-induced injury with daily administration of a neutrophil elastase inhibitor. The number of inflammatory cells in the bronchoalveolar lavage fluid (BALF) was also evaluated. In addition, the concentration of activated transforming growth factor (TGF)-β1 in the BALF and the expression of phospho-SMAD2/3 were investigated. Irradiated and LPS-treated mice developed pulmonary fibrosis after injury. The neutrophil elastase inhibitor significantly decreased the collagen deposition in lung parenchyma and improved the static lung compliance of injured lungs. Administration of the neutrophil elastase inhibitor also decreased the accumulation of neutrophils in the BALF, TGF-β1 activation, and expression of phospho-SMAD2/3. The authors conclude that inhibiting neutrophil elastase protects against the development of lung fibrosis after acute injury. In addition, these data suggest that this neutrophil elastase inhibitor has therapeutic potential for the fibroproliferative phase of ALI/ARDS.

Inhibitory effect of safflor yellow on pulmonary fibrosis

Myofibroblast plays an important role in the progression of pulmonary fibrosis, featured by the presence of α-smooth muscle actin (α-SMA). It has been a novel therapeutic target. Safflor yellow (SY) is extracted from safflower, a traditional Chinese medicine. The aim of our study is to investigate the effects of SY on rats of pulmonary fibrosis induced by bleomycin (BLM) and on differentiation of lung fibroblast into myofibroblast stimulated by transforming growth factor-β1 (TGF-β1). Two dose SY (intraperitoneal, 25, 50 mg/kg/d) were administered to rats treated by BLM consecutively for four weeks. It was found that SY alleviated the loss in body weight, the increase of hydroxyproline content in the lung tissues and pathologic changes of pulmonary fibrosis caused by BLM instillation. SY also prevented the increase of α-SMA positive cells and TGF-β1 expression induced by BLM. These effects were more significant when treatment with high-dose SY. Moreover, SY (0.05, 0.25, 1.25 mg/ml) inhibited the expression of α-SMA during differentiation of lung fibroblast into myofibroblast stimulated by TGF-β1. SY had anti-fibrotic effect in experiment and might be employed as a therapeutic candidate agent for attenuating pulmonary fibrosis.