Imaging pulmonary NF-kappaB activation and therapeutic effects of MLN120B and TDZD-8

Simultaneous Pretreatment of Aspirin and Omega-3 Fatty Acid Attenuates Nuclear Factor-κB Activation in a Murine Model with Ventilator-Induced Lung Injury

Ventilator-induced lung injury (VILI) is an important critical care complication. Nuclear factor-κB (NF-κB) activation, a critical signaling event in the inflammatory response, has been implicated in the tracking of the lung injury. The present study aimed to determine the effect of simultaneous pretreatment with enteral aspirin and omega-3 fatty acid on lung injury in a murine VILI model. We compared the lung inflammation after the sequential administration of lipopolysaccharides and mechanical ventilation between the pretreated simultaneous enteral aspirin and omega-3 fatty acid group and the non-pretreatment group, by quantifying NF-κB activation using an in vivo imaging system to detect bioluminescence signals. The pretreated group with enteral aspirin and omega-3 fatty acid exhibited a smaller elevation of bioluminescence signals than the non-pretreated group (p = 0.039). Compared to the non-pretreated group, the pretreatment group with simultaneous enteral aspirin and omega-3 fatty acid showed reduced expression of the pro-inflammatory cytokine, tumor necrosis factor-α, in bronchoalveolar lavage fluid (p = 0.038). Histopathological lung injury scores were also lower in the pretreatment groups compared to the only injury group. Simultaneous pretreatment with enteral administration of aspirin and omega-3 fatty acid could be a prevention method for VILI in patients with impending mechanical ventilation therapy.

Airways glutathione S-transferase omega-1 and its A140D polymorphism are associated with severity of inflammation and respiratory dysfunction in cystic fibrosis

BACKGROUND

Glutathione S-transferase omega-1 (GSTO1-1) is a cytosolic enzyme that modulates the S-thiolation status of intracellular factors involved in cancer cell survival or in the inflammatory response. Studies focusing on chronic obstructive pulmonary disease (COPD) have demonstrated that GSTO1-1 is detectable in alveolar macrophages, airway epithelium and in the extracellular compartment, where its functions have not been completely understood. Moreover GSTO1-1 polymorphisms have been associated with an increased risk to develop COPD. Against this background, the aim of this study was to evaluate GSTO1-1 levels and its polymorphisms in cystic fibrosis (CF) patients.

METHODS

Clinical samples from a previous study published by our groups were analyzed for GSTO1-1 levels and polymorphisms. For comparison, a model of lung inflammation in CFTR-knock out mice was also used.

RESULTS

Our data document that soluble GSTO1-1 can be found in the airways of CF patients and correlates with inflammatory parameters such as neutrophilic elastase and the chemokine IL-8. A negative correlation was found between GSTO1-1 levels and the spirometric parameter FEV1 and the FEV1/FVC ratio. Additionally, the A140D polymorphism of GSTO1-1 was associated with lower levels of the antiinflammatory mediators PGE2 and 15(S)-HETE, and with lower values of the FEV1/FVC ratio in CF subjects with the homozygous CFTR ΔF508 mutation.

CONCLUSIONS

Our data suggest that extracellular GSTO1-1 and its polymorphysms could have a biological and clinical significance in CF. Pathophysiological functions of GSTOs are far from being completely understood, and more studies are required to understand the role(s) of extracellular GSTO1-1 in inflamed tissues.

Modulation of LPS-induced inflammatory cytokine production by a novel glycogen synthase kinase-3 inhibitor

Sepsis is a serious condition that can lead to long-term organ damage and death. At the molecular level, the hallmark of sepsis is the elevated expression of a multitude of potent cytokines, i.e. a cytokine storm. For sepsis involving gram-negative bacteria, macrophages recognize lipopolysaccharide (LPS) shed from the bacteria, activating Toll-like-receptor 4 (TLR4), and triggering a cytokine storm. Glycogen synthase kinase-3 (GSK-3) is a highly active kinase that has been implicated in LPS-induced cytokine production. Thus, compounds that inhibit GSK-3 could be potential therapeutics for sepsis. Our group has recently described a novel and highly selective inhibitor of GSK-3 termed COB-187. In the present study, using THP-1 macrophages, we evaluated the ability of COB-187 to attenuate LPS-induced cytokine production. We found that COB-187 significantly reduced, at the protein and mRNA levels, cytokines induced by LPS (e.g. IL-6, TNF-α, IL-1β, CXCL10, and IFN-β). Further, the data suggest that the inhibition could be due, at least in part, to COB-187 reducing NF-κB (p65/p50) DNA binding activity as well as reducing IRF-3 phosphorylation at Serine 396. Thus, COB-187 appears to be a potent inhibitor of the cytokine storm induced by LPS.

NOD1/2 and the C-Type Lectin Receptors Dectin-1 and Mincle Synergistically Enhance Proinflammatory Reactions Both In Vitro and In Vivo

Purpose

Pathogens consist of a wide variety of evolutionarily conserved molecular structures that are recognized by pattern recognition receptors (PRRs) of innate immunity. Reasonably assuming that no single PRR is ever likely to be the sole trigger of the immune response during infection, a great deal remains unknown about collaborative mechanisms and consequential crosstalk effects between multiple PRRs belonging to different families. Here, we aimed to investigate inflammatory response to combined stimulation of cytosolic nucleotide-binding oligomerization domain (NOD) receptors: NOD1, NOD2 and membrane-bound C-type lectin receptors (CLRs): Mincle and Dectin-1 in comparison to individual stimulation both in vitro and in vivo.

Materials and Methods

For in vitro studies, we used human monocytic THP-1 cells endogenously expressing NOD1,2, as well as Mincle and Dectin-1 receptors. Using reporter gene and immunoassay approaches, we measured activity of key proinflammatory transcription factors (NF-κB and AP-1) and cytokine production after addition of specific PRR agonists or their pairwise combinations. In vivo NF-κB activity (bioluminescent detection in NF-κB-Luc transgenic mice), as well as cytokine levels in mouse blood serum, was measured 3 hours after intramuscular injection of PRR agonists.

Results

We detected that combined stimulation of NOD1/2 and C-type lectin receptors (Dectin-1, Mincle) strongly potentiates NF-κB and AP-1 transcription factor activity in human monocytic THP-1 cells, as well as resulting in enhanced levels of IL-8 cytokine production. We demonstrated that RIP2- and Syk-dependent signaling pathways downstream of NOD1/2 and Dectin-1/Mincle, respectively, are essential for the potentiated proinflammatory cell response. Lastly, we confirmed that synergy between NOD and C-type lectin receptors resulting in potentiated levels of NF-κB activation and cytokine (IL-6, KC) production also occurs in vivo.

Conclusion

These findings originally indicate cooperation between NODs and CLRs, leading to potentiated levels of proinflammatory immune response both in vitro and in vivo.

SN50 attenuates alveolar hypercoagulation and fibrinolysis inhibition in acute respiratory distress syndrome mice through inhibiting NF-κB p65 translocation

Background

It has been confirmed that NF-κB p65 signaling pathway is involved in the regulation of alveolar hypercoagulation and fibrinolysis inhibition in acute respiratory distress syndrome (ARDS). Whether SN50, a NF-κB cell permeable inhibitor, could attenuate alveolar hypercoagulation and fibrinolysis inhibition in ARDS remains to be elucidated.

Purpose

We explored the efficacy and potential mechanism of SN50 on alveolar hypercoagulation and fibrinolysis inhibition in ARDS in mice.

Materials and methods

Mouse ARDS was made by 50 μl of lipopolysaccharide (LPS) (4 mg/ml) inhalation. Male BALB/c mice were intraperitoneally injected with different does of SN50 1 h before LPS inhalation. Lung tissues were collected for hematoxylin-eosin (HE) staining, wet/dry ratio. Pulmonary expressions of tissue factor (TF), plasminogen activator inhibitor-1 (PAI-1), collagen III, as well as phosphorylated p65 (p-p65), p65 in nucleus (p’-p65), IκBα and IKKα/β were measured. Bronchoalveolar lavage fluid (BALF) was gathered to test the concentrations of TF, PAI-1, activated protein C (APC) and thrombinantithrombin complex (TAT). DNA binding activity of NF-κB p65 was also determined.

Results

After LPS stimulation, pulmonary edema and exudation and alveolar collapse occured. LPS also stimulated higher expressions of TF and PAI-1 in lung tissues, and higher secretions of TF, PAI-1, TAT and low level of APC in BALF. Pulmonary collagen III expression was obviously enhanced after LPS inhalation. At same time, NF-κB signaling pathway was activated with LPS injury, shown by higher expressions of p-p65, p’-p65, p-IKKα/β, p-Iκα in pulmonary tissue and higher level p65 DNA binding activity. SN50 dose-dependently inhibited TF, PAI-1 and collagen IIIexpressions, and decreased TF, PAI-1, TAT but increased APC in BALF. SN50 treatment attenuated pulmonary edema, exudation and reduced lung tissue damage as well. SN50 application significantly reduced p’-p65 expression and weakened p65 DNA binding activity, but expressions of p-p65, p-IKKα/β, p-Iκα in cytoplasm of pulmonary tissue were not affected.

Conclusions

SN 50 attenuates alveolar hypercoagulation and fibrinolysis inhibition in ARDS via inhibition of NF-κB p65 translocation. Our data demonstrates that NF-κB p65 pathway is a viable new therapeutic target for ARDS treatment.

CHF6001 Inhibits NF-κB Activation and Neutrophilic Recruitment in LPS-Induced Lung Inflammation in Mice

Inhibitors of phosphodiesterase 4 (PDE4) are potent anti-inflammatory agents, inhibiting the production of inflammatory mediators through the elevation of intracellular cAMP concentrations. We studied the activity of a novel PDE4 inhibitor, CHF6001, both in vitro in human cells and in vivo, using bioluminescence imaging (BLI) in mice lung inflammation. Mice transiently transfected with the luciferase gene under the control of an NF-κB responsive element (NF-κB-luc) have been used to assess the in vivo anti-inflammatory activity of CHF6001 in lipopolysaccharide (LPS)-induced lung inflammation. BLI as well as inflammatory cells and the concentrations of pro-inflammatory cytokines were monitored in bronchoalveolar lavage fluids (BALF) while testing in vitro its ability to affect the production of leukotriene B₄ (LTB₄), measured by LC/MS/MS, by LPS/LPS/N-formyl--methionyl--leucyl-phenylalanine (fMLP)-activated human blood. CHF6001 inhibited the production of LTB₄ in LPS/fMLP-activated human blood at sub-nanomolar concentrations. LPS-induced an increase of BLI signal in NF-κB-luc mice, and CHF6001 administered by dry powder inhalation decreased in parallel luciferase signal, cell airway infiltration, and pro-inflammatory cytokine concentrations in BALF. The results obtained provide in vitro and in vivo evidence of the anti-inflammatory activity of the potent PDE4 inhibitor CHF6001, showing that with a topical administration that closely mimics inhalation in humans, it efficiently disrupts the NF-κB activation associated with LPS challenge, an effect that may be relevant for the prevention of exacerbation episodes in chronic obstructive pulmonary disease subjects.

Nuclear factor-kappa B influences early phase of compensatory lung growth after pneumonectomy in mice

Background

Compensatory lung growth (CLG) is a well-established lung regeneration model. However, the sequential mechanisms, including unknown molecular triggers or regulators, remain unclear. Nuclear factor- kappa B (NF-κB) is known to be essential for inflammation and tissue regeneration; therefore, we investigated the role of NF-κB in CLG.

Methods

C57BL/6 J mice underwent either a left pneumonectomy or a thoracotomy (n = 77). Gene microarray analysis was performed to detect genes that were upregulated at 12 h after pneumonectomy. NF-κB protein expression was examined by immunohistochemistry and Western blot. To investigate the influence of NF-κB on CLG, either an NF-κB inhibitor SN50 or saline was administered following pneumonectomy and the degree of CLG was evaluated in each group by measuring the lung dry weight index (LDWI) and the mean linear intercept.

Results

Gene microarray analysis identified 11 genes that were significantly but transiently increased at 12 h after pneumonectomy. Among the 11 genes, NF-κB was selected based on its reported functions. Western blot analysis showed that NF-κB protein expression after pneumonectomy was significantly higher at 12 h compared to 48 h. Additionally, NF-κB protein expression at 12 h after pneumonectomy was significantly higher than at both 12 and 48 h after thoracotomy (p < 0.029 for all). NF-κB protein expression, evaluated through immunohistochemistry, was expressed mainly in type 2 alveolar epithelial cells and was significant increased 12 h after pneumonectomy compared to 48 h after pneumonectomy and both 12 and 48 h after thoracotomy (p < 0.001 for all). SN50 administration following pneumonectomy induced a significant decrease in NF-κB expression (p = 0.004) and LDWI compared to the vehicle administration (p = 0.009).

Conclusions

This is the first report demonstrating that NF-κB signaling may play a key role in CLG. Given its pathway is crucial in tissue regeneration of various organs, NF-κB may shed light on identification of molecular triggers or clinically usable key regulators of CLG.

In vivo monitoring of lung inflammation in CFTR-deficient mice

Background

Experimentally, lung inflammation in laboratory animals is usually detected by the presence of inflammatory markers, such as immune cells and cytokines, in the bronchoalveolar lavage fluid (BALF) of sacrificed animals. This method, although extensively used, is time, money and animal life consuming, especially when applied to genetically modified animals. Thus a new and more convenient approach, based on in vivo imaging analysis, has been set up to evaluate the inflammatory response in the lung of CFTR-deficient (CF) mice, a murine model of cystic fibrosis.

Methods

Wild type (WT) and CF mice were stimulated with P. aeruginosa LPS, TNF-alpha and culture supernatant derived from P. aeruginosa (strain VR1). Lung inflammation was detected by measuring bioluminescence in vivo in mice transiently transgenized with a luciferase reporter gene under the control of a bovine IL-8 gene promoter.

Results

Differences in bioluminescence (BLI) signal were revealed by comparing the two types of mice after intratracheal challenge with pro-inflammatory stimuli. BLI increased at 4 h after stimulation with TNF-alpha and at 24 h after administration of LPS and VR1 supernatant in CF mice with respect to untreated animals. The BLI signal was significantly more intense and lasted for longer times in CF animals when compared to WT mice. Analysis of BALF markers: leukocytes, cytokines and histology revealed no significant differences between CF and WT mice.

Conclusions

In vivo gene delivery technology and non-invasive bioluminescent imaging has been successfully adapted to CFTR-deficient mice. Activation of bIL-8 transgene promoter can be monitored by non-invasive BLI imaging in the lung of the same animal and compared longitudinally in both CF or WT mice, after challenge with pro-inflammatory stimuli. The combination of these technologies and the use of CF mice offer the unique opportunity of evaluating the impact of therapies aimed to control inflammation in a CF background.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0976-8) contains supplementary material, which is available to authorized users.

In vivo imaging of the lung inflammatory response to Pseudomonas aeruginosa and its modulation by azithromycin

Background

Chronic inflammation of the airways is a central component in lung diseases and is frequently associated with bacterial infections. Monitoring the pro-inflammatory capability of bacterial virulence factors in vivo is challenging and usually requires invasive methods.

Methods

Lung inflammation was induced using the culture supernatants from two Pseudomonas aeruginosa clinical strains, VR1 and VR2, isolated from patients affected by cystic fibrosis and showing different phenotypes in terms of motility, colony characteristics and biofilm production as well as pyoverdine and pyocyanine release. More interesting, the strains differ also for the presence in supernatants of metalloproteases, a family of virulence factors with known pro-inflammatory activity. We have evaluated the benefit of using a mouse model, transiently expressing the luciferase reporter gene under the control of an heterologous IL-8 bovine promoter, to detect and monitoring lung inflammation.

Results

In vivo imaging indicated that VR1 strain, releasing in its culture supernatant metalloproteases and other virulence factors, induced lung inflammation while the VR2 strain presented with a severely reduced pro-inflammatory activity. The bioluminescence signal was detectable from 4 to 48 h after supernatant instillation. The animal model was also used to test the anti-inflammatory activity of azithromycin (AZM), an antibiotic with demonstrated inhibitory effect on the synthesis of bacterial exoproducts. The inflammation signal in mice was in fact significantly reduced when bacteria grew in the presence of a sub-lethal dose of AZM causing inhibition of the synthesis of metalloproteases and other bacterial elements. The in vivo data were further supported by quantification of immune cells and cytokine expression in mouse broncho-alveolar lavage samples.

Conclusions

This experimental animal model is based on the transient transduction of the bovine IL-8 promoter, a gene representing a major player during inflammation, essential for leukocytes recruitment to the inflamed tissue. It appears to be an appropriate molecular read-out for monitoring the activation of inflammatory pathways caused by bacterial virulence factors. The data presented indicate that the model is suitable to functionally monitor in real time the lung inflammatory response facilitating the identification of bacterial factors with pro-inflammatory activity and the evaluation of the anti-inflammatory activity of old and new molecules for therapeutic use.

Azithromycin inhibits nuclear factor-κB activation during lung inflammation: an in vivo imaging study

We studied in vivo the potential involvement of nuclear factor-κB (NF-κB) pathway in the molecular mechanism of the anti-inflammatory and immunomodulatory activity of azithromycin in the lung. Mice transiently transfected with the luciferase gene under the control of a NF-κB responsive element were used to assess in vivo NF-κB activation by bioluminescence imaging. Bioluminescence as well as inflammatory cells and concentrations of proinflammatory cytokines in bronchoalveolar lavage fluids, were monitored in an acute model of pulmonary inflammation resulting from intratracheal instillation of lipopolysaccharide. Lipopolysaccharide (LPS) instillation induced a marked increase in lung bioluminescence in mice transiently transfected with the luciferase gene under the control of an NF-κB responsive element, with significant luciferase expression in resident cells such as endothelial and epithelial cells, as assessed by duoplex immunofluorescence staining. Activation of NF-κB and inflammatory cell lung infiltration linearly correlated when different doses of bortezomib were used to inhibit NF-κB activation. Pretreatment with azithromycin significantly decreased lung bioluminescence and airways cell infiltration induced by LPS, also reducing proinflammatory cytokines concentrations in bronchoalveolar lavages and inhibiting NF-κB nuclear translocation. The results obtained using a novel approach to monitor NF-κB activation, provided, for the first time, in vivo evidence that azithromycin treatment results in pulmonary anti-inflammatory activity associated with the inhibition of NF-κB activation in the lung.

Inhibitor of nuclear factor-κB, SN50, attenuates lipopolysaccharide-induced lung injury in an isolated and perfused rat lung model

NF-κB cell permeable inhibitory peptide (SN50) inhibits translocation of nuclear factor-κB (NF-κB) and production of inflammatory cytokines that are implicated in lipopolysaccharide (LPS)-induced lung injury (LPSLI). However, the protective effect of SN50 in LPSLI is unclear. We explored the cellular and molecular mechanisms of SN50 treatment in LPSLI. LPSLI was induced by intratracheal instillation of 10 mg/kg LPS using an isolated and perfused rat lung model. SN50 was administered in the perfusate 15 minutes before LPS was administered. Hemodynamics, lung histologic change, inflammatory responses, and activation of apoptotic pathways were evaluated. After LPSLI, increased pulmonary vascular permeability and lung weight gain was observed. The levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, myeloperoxidase, and macrophage inflammatory protein-2 increased in bronchoalveolar lavage fluids. Lung-tissue expression of TNF-α, IL-1β, mitogen-activated protein kinases (MAPKs), caspase-3, p-AKT (serine-threonine kinase, also known as protein kinase B), and plasminogen activator inhibitor-1 (PAI-1) was greater in the LPS group compared with controls. Upregulation and activation of NF-κB was associated with increased lung injury in LPSLI. SN50 attenuated the inflammatory responses, including expression of IL-1β, TNF-α, myeloperoxidase, MAPKs, PAI-1, and NF-κB; downregulation of apoptosis indicated by caspase-3 and p-AKT expression was also observed. In addition, SN50 mitigated the increase in the lung weight, pulmonary vascular permeability, and lung injury. In conclusion, LPSLI is associated with inflammatory responses, apoptosis, and coagulation. NF-κB is an important therapeutic target in the treatment of LPSLI. SN50 inhibits translocation of NF-κB and attenuates LPSLI.

Targeting glycogen synthase kinase-3β to prevent hyperoxia-induced lung injury in neonatal rats

The pathological hallmarks of bronchopulmonary dysplasia (BPD), a chronic lung disease of premature infants, include inflammation, arrested alveolarization, and dysregulated angiogenesis. Severe BPD is often complicated by pulmonary hypertension (PH) that significantly increases morbidity and mortality. Glycogen synthase kinase (GSK)-3β plays a pivotal role in embryonic development, cell proliferation and survival, and inflammation by modulating multiple signaling pathways, particularly the nuclear transcription factor, NF-κB, and Wnt/β-catenin pathways. Aberrant GSK-3β signaling is linked to BPD. We tested the hypothesis that inhibition of GSK-3β is beneficial in preventing hyperoxia-induced neonatal lung injury, an experimental model of BPD. Newborn rats were exposed to normoxia or hyperoxia (90% oxygen), and received daily intraperitoneal injections of placebo (DMSO) or SB216763, a specific pharmacological inhibitor of GSK-3β, for 14 days. Hyperoxia exposure in the presence of the placebo increased GSK-3β phosphorylation, which was correlated with increased inflammation, decreased alveolarization and angiogenesis, and increased pulmonary vascular remodeling and PH. However, treatment with SB216763 decreased phosphorylation of NF-κB p65, expression of monocyte chemotactic protein-1, and lung inflammation during hyperoxia. Furthermore, treatment with the GSK-3β inhibitor also improved alveolarization and angiogenesis, and decreased pulmonary vascular remodeling and PH. These data indicate that GSK-3β signaling plays an important role in the pathogenesis of hyperoxia-induced neonatal lung injury, and that inhibition of GSK-3β is beneficial in preventing inflammation and protecting alveolar and vascular structures during hyperoxia. Thus, targeting GSK-3β signaling may offer a novel strategy to prevent and treat preterm infants with BPD.

Enhanced detection of myeloperoxidase activity in deep tissues through luminescent excitation of near-infrared nanoparticles

A previous study reported the use of luminol for the detection of myeloperoxidase (MPO) activity using optical imaging in infiltrating neutrophils under inflammatory disease conditions. The detection is based on a photon-emitting reaction between luminol and an MPO metabolite. Because of tissue absorption and scattering, however, luminol-emitted blue light can be efficiently detected from superficial inflammatory foci only. In this study we report a chemiluminescence resonance energy transfer (CRET) methodology in which luminol-generated blue light excites nanoparticles to emit light in the near-infrared spectral range, resulting in remarkable improvement of MPO detectability in vivo. CRET caused a 37-fold increase in luminescence emission over luminol alone in detecting MPO activity in lung tissues after lipopolysaccharide challenge. We demonstrated a dependence of the chemiluminescent signal on MPO activity using MPO-deficient mice. In addition, co-administration of 4-aminobenzoic acid hydrazide (4-ABAH), an irreversible inhibitor of MPO, significantly attenuated luminescent emission from inflamed lungs. Inhibition of nitric oxide synthase with a nonspecific inhibitor, L-NAME, had no effect on luminol-mediated chemiluminescence production. Pretreatment of mice with MLN120B, a selective inhibitor of IKK-2, resulted in suppression of neutrophil infiltration to the lung tissues and reduction of MPO activity. We also demonstrated that CRET can effectively detect MPO activity at deep tissue tumor foci due to tumor development-associated neutrophil infiltration. We developed a sensitive MPO detection methodology that provides a means for visualizing and quantifying oxidative stress in deep tissue. This method is amenable to rapid evaluation of anti-inflammatory agents in animal models.

Imaging inflammation: molecular strategies to visualize key components of the inflammatory cascade, from initiation to resolution

Dysregulation of inflammation is central to the pathogenesis of innumerable human diseases. Understanding and tracking the critical events in inflammation are crucial for disease monitoring and pharmacological drug discovery and development. Recent progress in molecular imaging has provided novel insights into spatial associations, molecular events and temporal sequelae in the inflammatory process. While remaining a burgeoning field in pre-clinical research, increasing application in man affords researchers the opportunity to study disease pathogenesis in humans in situ thereby revolutionizing conventional understanding of pathophysiology and potential therapeutic targets. This review provides a description of commonly used molecular imaging modalities, including optical, radionuclide and magnetic resonance imaging, and details key advances and translational opportunities in imaging inflammation from initiation to resolution.