The Role of Matrix Metalloproteinases in Development, Repair, and Destruction of the Lungs

Matrix metalloproteinases activation in Toxocara canis induced pulmonary pathogenesis

BACKGROUND

Toxocara canis, a source of visceral larva migrans, causes toxocariasis and induces respiratory symptoms. The reasons by which the pulmonary pathological alteration in the lungs infected with T. canis remain unclear.

METHODS

The involvement of the pulmonary pathological alteration by histology, enzyme activity, and Western blot analysis in the lungs of BALB/c mice after the infection of 2000 embryonated eggs.

RESULTS

The pathological effects gradually increased after the infection culminated in severe leukocyte infiltration and hemorrhage from days 4-14 post-inoculation. Gelatin zymography using substrate showed that the relative activity of matrix metalloproteinase (MMP) -9 and MMP-2 significantly increased in T. canis-infected mice. Western blot analysis indicated that the MMPs protein level of fibronectin monomer significantly increased in T. canis-infected mice compared with that in uninfected control. T. canis larvae mainly initiated leukocyte infiltration and hemorrhage in the lungs.

CONCLUSION

These phenomena subsequently induced the activities of MMPs in parallel with the pathological changes in early stage pulmonary inflammation. In conclusion, T. canis larval migration activated the MMPs and caused pulmonary pathogenesis.

MMP-9-C1562T polymorphism and susceptibility to chronic obstructive pulmonary disease: A meta-analysis

BACKGROUND

To comprehensively evaluate the association between the polymorphism of matrix metalloproteinase-9 (MMP-9)-C1562T (rs3918242) and susceptibility to chronic obstructive pulmonary disease (COPD) in middle-aged and elderly patients through Meta-analysis.

METHODS

PubMed, EMBASE, CNKI, Wanfang, VIP, and other databases were searched by computer in the inception to August 2019 to collect all the case-control studies that met the inclusion criteria in this literature. Meta-analysis was performed using Stata 15.0, including the OR value calculations of the association between the merged MMP-9-C1562T polymorphism and the COPD susceptibility. Subgroup analysis, sensitivity analysis, and publication bias test were also performed. A total of 13 literature were included in this Meta-analysis with a total of 2512 cases and 2716 controls.

RESULTS

The results have shown that the OR of MMP-9-C1562T T allele to C allele was 0.35 (95% confidence interval [CI]: 0.23-0.52, P < .01). The subgroup analysis of ethnicity result showed that the merged OR of MMP-9-C1562T T allele to C allele was 0.24 (95% CI: 0.17-0.34, P < .01) in Caucasian while the merged OR was 0.62 (95% CI: 0.22-1.70, P > .05) in Asian. However, there were no statistically significant models in the dominant, recessive, homozygote and heterozygote genetic models.

CONCLUSION

The MMP-9-C1562T polymorphism was associated with the susceptibility to middle-aged and elderly COPD patients. Compared with T allele, C allele increased the risk of disease, especially in Caucasian, but not found in Asian.

LPS aggravates lung inflammation induced by RSV by promoting the ERK-MMP-12 signaling pathway in mice

Background

RSV can lead to persistent airway inflammation and airway hyperresponsiveness (AHR), and is intimately associated with childhood recurrent wheezing and asthma, but the underlying mechanisms remain unclear. Lipopolysaccharide (LPS) is also implicated in the onset and exacerbation of asthma. However, whether inhalation of LPS can boost airway inflammation induced by RSV is not clear. In this study, we utilized an LPS- and RSV-superinfected mouse model to explore underlying pathogenesis.

Methods

Mice were infected with RSV on day 0 and inoculated with LPS from day 35 to day 41, samples were collected on day 42. Inflammatory cells, lung histopathology and AHR were measured. Cytokines were detected by ELISA and ERK, JNK, p38 was determined by western blot. MMP408, PD98059, SP600125 and SB203580 were used to inhibit MMP-12, ERK, JNK and p38 respectively.

Results

LPS exposure superimposed on RSV-infected lungs could lead to more vigorous cellular influx, lung structures damage, augmented AHR and higher MMP-12 levels. Inhibition of MMP-12 or ERK signaling pathway in vivo both diminished LPS-driven airway inflammation and AHR.

Conclusions

Exposure to LPS in RSV-infected mice is associated with enhanced increases in ERK-MMP-12 expression that translates into increased lung inflammation and AHR. These findings contribute novel information to the field investigating the onset of post-RSV bronchiolitis recurrent wheezing as a result of LPS exposure.

Myeloid-specific blockade of Notch signaling alleviates murine pulmonary fibrosis through regulating monocyte-derived Ly6clo MHCIIhi alveolar macrophages recruitment and TGF-β secretion

Macrophages in lung, including resident alveolar macrophages (AMs) and interstitial macrophages (IMs), and monocyte-derived macrophages, play important roles in pulmonary fibrosis (PF), but mechanisms underlying their differential regulation remain unclear. Recombination signal-binding protein Jκ (RBP-J)-mediated Notch signaling regulates macrophage development and phenotype. Here, using bleomycin-induced fibrosis model combined with myeloid-specific RBP-J disruption (RBP-J^cKO ) mouse, we investigated the role of Notch signaling in macrophages during PF. Compared with the control, RBP-J^cKO mice exhibited alleviated lung fibrosis as manifested by reduced collagen deposition and inflammation, and decreased TGF-β production. FACS analysis suggested that decreased Ly6c^lo MHCII^hi AMs might make the major contribution to attenuated fibrogenesis in RBP-J^cKO mice, probably by reduced inflammatory factor release and enhanced matrix metalloproteinases expression. Using clodronate-mediated macrophage depletion in RBP-J^ckO mice, we demonstrated that embryonic-derived AMs play negligible role in lung fibrosis, which was further supported by adoptive transfer experiments. Moreover, on CCR2 knockout background, the effect of RBP-J deficiency on fibrogenesis was not elicited, suggesting that Notch regulated monocyte-derived AMs. Co-culture experiment showed that monocyte-derived AMs from RBP-J^cKO mice exhibit reduced myofibroblast activation due to decreased TGF-β secretion. In conclusion, monocyte-derived Ly6c^lo MHCII^hi AMs, which are regulated by RBP-J-mediated Notch signaling, play an essential role in lung fibrosis.

Size-Dependent Pulmonary Impact of Thin Graphene Oxide Sheets in Mice: Toward Safe-by-Design

Safety assessment of graphene-based materials (GBMs) including graphene oxide (GO) is essential for their safe use across many sectors of society. In particular, the link between specific material properties and biological effects needs to be further elucidated. Here, the effects of lateral dimensions of GO sheets in acute and chronic pulmonary responses after single intranasal instillation in mice are compared. Micrometer-sized GO induces stronger pulmonary inflammation than nanometer-sized GO, despite reduced translocation to the lungs. Genome-wide RNA sequencing also reveals distinct size-dependent effects of GO, in agreement with the histopathological results. Although large GO, but not the smallest GO, triggers the formation of granulomas that persists for up to 90 days, no pulmonary fibrosis is observed. These latter results can be partly explained by Raman imaging, which evidences the progressive biotransformation of GO into less graphitic structures. The findings demonstrate that lateral dimensions play a fundamental role in the pulmonary response to GO, and suggest that airborne exposure to micrometer-sized GO should be avoided in the production plant or applications, where aerosolized dispersions are likely to occur. These results are important toward the implementation of a safer-by-design approach for GBM products and applications, for the benefit of workers and end-users.

Alveolar heparan sulfate shedding impedes recovery from bleomycin-induced lung injury

The pulmonary epithelial glycocalyx, an anionic cell surface layer enriched in glycosaminoglycans such as heparan sulfate and chondroitin sulfate, contributes to the alveolar barrier. Direct injury to the pulmonary epithelium induces shedding of heparan sulfate into the air space; the impact of this shedding on recovery after lung injury is unknown. Using mass spectrometry, we found that heparan sulfate was shed into the air space for up to 3 wk after intratracheal bleomycin-induced lung injury and coincided with induction of matrix metalloproteinases (MMPs), including MMP2. Delayed inhibition of metalloproteinases, beginning 7 days after bleomycin using the nonspecific MMP inhibitor doxycycline, attenuated heparan sulfate shedding and improved lung function, suggesting that heparan sulfate shedding may impair lung recovery. While we also observed an increase in air space heparanase activity after bleomycin, pharmacological and transgenic inhibition of heparanase in vivo failed to attenuate heparan sulfate shedding or protect against bleomycin-induced lung injury. However, experimental augmentation of airway heparanase activity significantly worsened post-bleomycin outcomes, confirming the importance of epithelial glycocalyx integrity to lung recovery. We hypothesized that MMP-associated heparan sulfate shedding contributed to delayed lung recovery, in part, by the release of large, highly sulfated fragments that sequestered lung-reparative growth factors such as hepatocyte growth factor. In vitro, heparan sulfate bound hepatocyte growth factor and attenuated growth factor signaling, suggesting that heparan sulfate shed into the air space after injury may directly impair lung repair. Accordingly, administration of exogenous heparan sulfate to mice after bleomycin injury increased the likelihood of death due to severe lung dysfunction. Together, our findings demonstrate that alveolar epithelial heparan sulfate shedding impedes lung recovery after bleomycin.

Current Understanding of Cytomegalovirus Reactivation in Critical Illness

Cytomegalovirus (CMV) reactivation has been described in adults with critical illness caused by diverse etiologies, especially severe sepsis, and observational studies have linked CMV reactivation with worse clinical outcomes in this setting. In this study, we review observational clinical data linking development of CMV reactivation with worse outcomes in patients in the intensive care unit, discuss potential biologically plausible mechanisms for a causal association, and summarize results of initial interventional trials that examined the effects of CMV prevention. These data, taken together, highlight the need for a randomized, placebo-controlled efficacy trial (1) to definitively determine whether prevention of CMV reactivation improves clinical outcomes of patients with critical illness and (2) to define the underlying mechanism(s).

β1 Integrin regulates adult lung alveolar epithelial cell inflammation

Integrins, the extracellular matrix receptors that facilitate cell adhesion and migration, are necessary for organ morphogenesis; however, their role in maintaining adult tissue homeostasis is poorly understood. To define the functional importance of β1 integrin in adult mouse lung, we deleted it after completion of development in type 2 alveolar epithelial cells (AECs). Aged β1 integrin-deficient mice exhibited chronic obstructive pulmonary disease-like (COPD-like) pathology characterized by emphysema, lymphoid aggregates, and increased macrophage infiltration. These histopathological abnormalities were preceded by β1 integrin-deficient AEC dysfunction such as excessive ROS production and upregulation of NF-κB-dependent chemokines, including CCL2. Genetic deletion of the CCL2 receptor, Ccr2, in mice with β1 integrin-deficient type 2 AECs impaired recruitment of monocyte-derived macrophages and resulted in accelerated inflammation and severe premature emphysematous destruction. The lungs exhibited reduced AEC efferocytosis and excessive numbers of inflamed type 2 AECs, demonstrating the requirement for recruited monocytes/macrophages in limiting lung injury and remodeling in the setting of a chronically inflamed epithelium. These studies support a critical role for β1 integrin in alveolar homeostasis in the adult lung.

Amorphous silica nanoparticle-induced pulmonary inflammatory response depends on particle size and is sex-specific in rats

Due to mass production and extensive use, the potential adverse health effects of amorphous silica nanoparticles (ASiNPs) have received a significant attention from the public and researchers. However, the relationship between physicochemical properties of ASiNPs and their health effects is still unclear. In this study, we manufactured two types of ASiNPs of different diameters (20 and 50 nm) and compared the toxic response induced in rats after intratracheal instillation (75, 150 or 300 μg/rat). There were no dose-related differences in mortality, body weight gain or organ weight between the groups. However both types of ASiNPs significantly decreased the proportion of neutrophils in male rats, whereas the levels of hemoglobin and hematocrit were markedly reduced only in female rats instilled with 20 nm-ASiNPs. ASiNPs-induced lung tissue damage seemed to be more evident in the 20 nm ASiNP-treated group and in female rats than male rats. Similarly, expression of caveolin-1 and matrix metalloproteinase-9 seemed to be most notably enhanced in female rats treated with 20 nm-ASiNPs. The total number of bronchial alveolar lavage cells significantly increased in rats instilled with 20 nm-ASiNPs, accompanying a decrease in the proportion of macrophages and an increase in polymorphonuclear leukocytes. Moreover, secretion of inflammatory mediators clearly increased in human bronchial epithelial cells treated with 20 nm-ASiNPs, but not in those treated with 50 nm-ASiNPs. These results suggest that pulmonary effects of ASiNPs depend on particle size. Sex-dependent differences should also be carefully considered in understanding nanomaterial-induced adverse health effects.

A Dual Role for Macrophages in Modulating Lung Tissue Damage/Repair during L2 Toxocara canis Infection

Macrophages that are classically activated (M1) through the IFN-γ/STAT1 signaling pathway have a major role in mediating inflammation during microbial and parasitic infections. In some cases, unregulated inflammation induces tissue damage. In helminth infections, alternatively activated macrophages (M2), whose activation occurs mainly via the IL-4/STAT6 pathway, have a major role in mediating protection against excessive inflammation, and has been associated with both tissue repair and parasite clearance. During the lung migratory stage of Toxocara canis, the roles of M1 and M2 macrophages in tissue repair remain unknown. To assess this, we orally infected wild-type (WT) and STAT1 and STAT6-deficient mice (STAT1^-/- and STAT6^-/-) with L2 T. canis, and evaluated the role of M1 or M2 macrophages in lung pathology. The absence of STAT1 favored an M2 activation pattern with Arg1, FIZZ1, and Ym1 expression, which resulted in parasite resistance and lung tissue repair. In contrast, the absence of STAT6 induced M1 activation and iNOS expression, which helped control parasitic infection but generated increased inflammation and lung pathology. Next, macrophages were depleted by intratracheally inoculating mice with clodronate-loaded liposomes. We found a significant reduction in alveolar macrophages that was associated with higher lung pathology in both WT and STAT1^-/- mice; in contrast, STAT6^-/- mice receiving clodronate-liposomes displayed less tissue damage, indicating critical roles of both macrophage phenotypes in lung pathology and tissue repair. Therefore, a proper balance between inflammatory and anti-inflammatory responses during T. canis infection is necessary to limit lung pathology and favor lung healing.

Comparison of cytokine profiles induced by nonlethal and lethal doses of influenza A virus in mice

Influenza viruses are among the most common human pathogens and are responsible for causing extensive seasonal morbidity and mortality. To investigate the immunological factors associated with severe influenza infection, the immune responses in mice infected with nonlethal (LD0) doses of A/PR/8/34 (H1N1) influenza virus were compared with those of mice infected with a lethal dose (LD100) of the virus. The virus titer and activation of retinoic acid-inducible gene (RIG)-I-like receptor signaling pathways were similar in the mice infected with LD0 and LD100 at 2 days post-infection; however, mice infected with LD100 exhibited a greater abundance of cytokines and a more diverse cytokine profile. Infection with LD100 induced the expression of the following factors: Interleukins (ILs), IL-4, IL-7, IL-10, IL-11, IL-12p40, IL-13 and IL-15; inflammatory chemokines, C-C motif chemokine ligand (CCL)2, CCL3/4, CCL12, CCL17, CCL19; and lung injury-associated cytokines, leptin, leukaemia inhibitory factor, macrophage colony stimulating factor, pentraxin (PTX)2 and PTX3, WNT1-inducible-signaling pathway protein 1, matrix metallopeptidase (MMP)-2, MMP-3, proprotein convertase subtilisin/kexin type 9, and T cell immunoglobulin and mucin domain. Switching in macrophage polarization from M1 to M2 was evidenced by the increase in M2 markers, including arginase-1 (Arg1) and early growth response protein 2 (Egr2), in the lungs of mice infected with LD100. Since IL-12 and interferon-γ are the major T helper (Th)1 cytokines, increased expression of interferon regulatory factor 4, IL-4, IL-10 and IL-13 promoted the differentiation of naïve CD4⁺ T cells into Th2 cells. In conclusion, the present study identified key cytokines involved in the pathogenicity of influenza infection, and demonstrated that lethal influenza virus infection induces a mixed Th1/Th2 response.

Comparative Study of Cytokine Levels in Different Respiratory Samples in Mild-to-Moderate AECOPD Patients

BACKGROUND

Matrix metalloproteinase-12 (MMP-12) and Tissue inhibitor of metalloproteinase-4 (TIMP-4) play important roles in the pathophysiology of chronic obstructive pulmonary disease (COPD). Subjects of many previous studies were patients with severe and very severe COPD. However, there are comparatively few studies on patients with mild-to-moderate COPD. Our aim was to measure MMP-12 and TIMP-4 levels and to compare its levels in various materials in patients with mild-to-moderate acute exacerbation of chronic obstructive pulmonary disease (AECOPD). We also compared which of the two materials of these biomarkers was better correlated with disease severity and DODE index.

METHODS

A total of 39 patients with AECOPD and 25 control subjects were enrolled in our study. MMP-12 and TIMP-4 in different respiratory samples were detected by ELISA.

RESULTS

Expression levels of MMP-12 in bronchoalveolar lavage fluid (BALF) and exhaled breath condensate (EBC) and TIMP-4 in BALF were significantly higher in AECOPD patients than that in healthy subjects (P < 0.001). However, there was no significant difference in TIMP-4 level in EBC of AECOPD patients compared to healthy subjects (P = 0.0527). The levels of MMP-12 in BALF and EBC and TIMP-4 in BAFL of AECOPD patients were significantly correlated with FEV1% predicted (P < 0.001). However, in AECOPD patients, there was no significant correlation between TIMP-4 levels in EBC and BODE index (r = 0.4175, P = 0.0559).

CONCLUSION

During mild-to-moderate AECOPD, the levels of MMP-12 and TIMP-4 in BALF were better correlated with FEV1% predicted and BODE index than that in EBC, indicating that they may be new target interventions for pharmacology to prevent and/or treat AECOPD.

MKL1 overexpression predicts poor prognosis in patients with papillary thyroid cancer and promotes nodal metastasis

Papillary thyroid cancer (PTC), the most common thyroid malignancy, has a strong propensity for cervical lymph node metastasis (LNM), which increases the risk of locoregional recurrence and decreases survival probability in some high-risk groups. Hence, there is a pressing requirement for a reliable biomarker to predict LNM in thyroid cancer. In the present study, MKL1 (also known as MRTFA) expression was significantly increased in PTC patients with LNM compared with those without. Further receiver operating characteristic (ROC) analysis showed that MKL1 expression had a diagnostic value in the differentiation of LNM in PTC. Furthermore, Kaplan-Meier analysis revealed that high MKL1 expression was associated with significantly decreased survival in PTC. Additionally, our study indicated that MKL1 promoted the migration and invasion of PTC cells. MKL1 interacted with and recruited Smad3 to the promoter of MMP2 to activate MMP2 transcription upon treatment with TGF-β. Moreover, there was significant correlation between expression of TGF-β, MKL1 and MMP2 in our clinical cohort of specimens from individuals with PTC. Our results suggest that the detection of MKL1 expression could be used to predict cervical LNM and inform post-operative follow-up in individuals with PTC.

Prevotella intermedia and periodontitis are associated with severe asthma

BACKGROUND

Periodontitis, an inflammatory disease of multibacterial etiology that affects the protective and supporting tissues surrounding teeth, can influence the course of respiratory diseases, such as asthma, due to epithelial alterations arising from inflammatory and immunological processes, bronchial remodeling, or by the aspiration of pathogenic colonizers found in periodontal pockets. This study evaluated the levels of periodontal pathogens Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans in the subgingival biofilm of individuals with and without severe asthma.

METHODS

A case-control study enrolling 457 individuals (220 with asthma and 237 without asthma) was conducted at the Program for Control of Asthma in Bahia (ProAR) Clinic located in Salvador, Bahia, Brazil. A structured questionnaire was used to obtain data on sociodemographic, health status, and lifestyle habits. A clinical periodontal assessment was performed, including bleeding on probing, probing depth, and clinical attachment level. Subgingival biofilm was collected at the deepest site of each sextant, and bacterial DNA was extracted. Quantitative real-time PCR analysis was performed to detect and relatively quantify periodontopathogens in the biofilm.

RESULTS

Statistically significant positive associations were found between periodontitis and severe asthma, (odds ratio [OR]_adjusted] : 4.00; 95% confidence interval [CI]: 2.26 to 7.10). High levels of P. intermedia were found in association with the presence of severe asthma (OR_adjusted : 2.64; 95% CI: 1.62 to 4.39; P < 0.01).

CONCLUSIONS

The present results suggest that periodontitis and P. intermedia are associated with severe asthma. However, the functional consequences of this dysbiosis upon asthma susceptibility and its phenotypes remain unclear.

Severity of chronic obstructive pulmonary disease with 'exacerbator with emphysema phenotype' is associated with potential biomarkers

OBJECTIVE

The present study was designed to investigate the biomarkers levels of fractalkine (FKN), neutrophil elastase (NE) and matrix metalloproteinase-12 (MMP-12) in chronic obstructive pulmonary disease (COPD) with 'exacerbator with emphysema phenotype' and to evaluate the associations between the biomarkers levels and the severity of disease by spirometric measurements.

METHODS

A total of 84 COPD patients and 49 healthy controls were enrolled in our study. ELISA were utilised to detect the FKN, MMP-12 and NE in serum from all subjects.

RESULTS

FKN (p<0.001), NE (p=0.039) and MMP-12 (p<0.001) in serum of COPD patients showed higher levels than that of healthy control subjects. Serum FKN (p<0.001), MMP-12 (p<0.001) and NE (p=0.043) levels were significantly higher in severe and very severe COPD patients than that in mild and moderate COPD patients. Circulating FKN, MMP-12 and NE expression levels were significantly elevated (p<0.001) in COPD smokers compared with COPD non-smokers. The smoke pack years were negatively correlated with FEV₁%pred (r=-0.5036), FEV₁/FVC ratio (r=-0.2847) (FEV, forced expiratory volume; FVC, forced vital capacity). Similarly, we observed a strong positive correlation between the smoke pack years and serum levels of FKN (r=0.4971), MMP-12 (r=0.4315) and NE (r=0.2754). FEV₁%pred was strongly negatively correlated with cytokine levels of FKN (r=-0.4367), MMP-12 (r=-0.3295) and NE (r=-0.2684). Likewise, FEV₁/FVC ratio was negatively correlated with mediators of inflammation levels of FKN (r=-0.3867), MMP-12 (r=-0.2941) and NE (r=-0.2153).

CONCLUSION

Serum FKN, MMP-12 and NE concentrations in COPD patients are directly associated with the severity of COPD with 'exacerbator with emphysema phenotype'. This finding suggests that FKN, MMP-12 and NE might play an important role in the pathophysiology of COPD.

Riociguat for treatment of pulmonary hypertension in COPD: a translational study

Chronic obstructive pulmonary disease (COPD), which comprises the phenotypes of chronic bronchitis and emphysema, is often associated with pulmonary hypertension (PH). However, currently, no approved therapy exists for PH-COPD. Signalling of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) axis plays an important role in PH and COPD.We investigated the treatment effect of riociguat, which promotes the NO-cGMP pathway, in the mouse model of smoke-induced PH and emphysema in a curative approach, and retrospectively analysed the effect of riociguat treatment on PH in single patients with PH-COPD.In mice with established PH and emphysema (after 8 months of cigarette smoke exposure), riociguat treatment for another 3 months fully reversed PH. Moreover, histological hallmarks of emphysema were decreased. Microarray analysis revealed involvement of different signalling pathways, e.g. related to matrix metalloproteinases (MMPs). MMP activity was decreased in vivo by riociguat. In PH-COPD patients treated with riociguat (n=7), the pulmonary vascular resistance, airway resistance and circulating MMP levels decreased, while oxygenation at rest was not significantly changed.Riociguat may be beneficial for treatment of PH-COPD. Further long-term prospective studies are necessary to investigate the tolerability, efficacy on functional parameters and effect specifically on pulmonary emphysema in COPD patients.

The etiologic origins for chronic obstructive pulmonary disease

COPD, characterized by long-term poorly irreversible airway limitation and persistent respiratory symptoms, has resulted in enormous challenges to human health worldwide, with increasing rates of prevalence, death, and disability. Although its origin was thought to be in the interactions of genetic with environmental factors, the effects of environmental factors on the disease during different life stages remain little known. Without clear mechanisms and radical cure for it, early screening and prevention of COPD seem to be important. In this review, we will discuss the etiologic origins for poor lung function and COPD caused by specific adverse effects during corresponding life stages, as well as try to find new insights and potential prevention strategies for this disease.

Endothelial stromelysin1 regulation by the forkhead box-O transcription factors is crucial in the exudative phase of acute lung injury

Enhanced vascular permeability is associated with inflammation and edema in alveoli during the exudative phase of acute respiratory distress syndrome (ARDS). Mechanisms leading to the endothelial contribution on the early exudative stage of ARDS are not precise. We hypothesized that modulation of endothelial stromelysin1 expression and activity by Akt1-forkhead box-O transcription factors 1/3a (FoxO1/3a) pathway could play a significant role in regulating pulmonary edema during the initial stages of acute lung injury (ALI). We utilized lipopolysaccharide (LPS)-induced mouse ALI model in vivo and endothelial barrier resistance measurements in vitro to determine the specific role of the endothelial Akt1-FoxO1/3a-stromelysin1 pathway in ALI. LPS treatment of human pulmonary endothelial cells resulted in increased stromelysin1 and reduced tight junction claudin5 involving FoxO1/3a, associated with decreased trans-endothelial barrier resistance as determined by electric cell-substrate impedance sensing technology. In vivo, LPS-induced lung edema was significantly higher in endothelial Akt1 knockdown (EC-Akt1^-/-) compared to wild-type mice, which was reversed upon treatment with FoxO inhibitor (AS1842856), stromelysin1 inhibitor (UK356618) or with shRNA-mediated FoxO1/3a depletion in the mouse lungs. Overall, our study provides the hope that targeting FoxO and styromelysin1 could be beneficial in the treatment of ALI.

Acute Moraxella catarrhalis Airway Infection of Chronically Smoke-Exposed Mice Increases Mechanisms of Emphysema Development: A Pilot Study

In chronic obstructive pulmonary disease (COPD), acute exacerbations and emphysema development are characteristics for disease pathology. COPD is complicated by infectious exacerbations with acute worsening of respiratory symptoms with Moraxella catarrhalis as one of the most frequent pathogens. Although cigarette smoke (CS) is the primary risk factor, additional molecular mechanisms for emphysema development induced by bacterial infections are incompletely understood. We investigated the impact of M. catarrhalis on emphysema development in CS exposed mice and asked whether an additional infection would induce a solubilization of pro-apoptotic and pro-inflammatory endothelial monocyte-activating-protein-2 (EMAPII) to exert its activities in the pulmonary microvas-culature and other parts of the lungs not exposed directly to CS.

Mice were exposed to smoke (6 or 9 months) and/or infected with M. catarrhalis. Lungs, bronchoalveolar lavage fluid (BALF), and plasma were analyzed.

CS exposure reduced ciliated area, caused rarefaction of the lungs, and induced apoptosis. EMAPII was increased independent of prior smoke exposure in BALF of infected mice. Importantly, acute M. catarrhalis infection increased release of matrixmetalloproteases-9 and -12, which are involved in emphysema development and comprise a mechanism of EMAPII release.

Our data suggest that acute M. catarrhalis infection represents an independent risk factor for emphysema development in smoke-exposed mice.

Matrix remodeling in chronic lung diseases

Multicellular organisms synthesize and renew components of their subcellular and scaffolding proteins, collectively known as the extracellular matrix molecules (ECMs). In the lung, ECMs maintain tensile strength, elasticity, and dictate the specialized function of multiple cell lineages. These functions are critical in lung homeostatic processes including cellular migration and proliferation during morphogenesis or in response to repair. Alterations in lung ECMs that expose cells to new cryptic fragments, generated in response to endogenous proteinases or exogenous toxins, are associated with the development of several common respiratory diseases. How lung ECMs provide or relay vital signals to epithelial and mesenchymal cells has shed new light on development and progression of several common chronic respiratory diseases. This review will consider how ECMs regulate lung homeostasis and their reorganization under pathological conditions that can modulate the inflammatory diseases asthma, chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). Better understanding of changes in the distribution of lung ECM could provide novel therapeutic approaches to treat chronic lung diseases.

Role of inflammatory cells in airway remodeling in COPD

COPD is characterized by chronic bronchitis, chronic airway obstruction, and emphysema, leading to a progressive and irreversible decline in lung function. Inflammation is central for the development of COPD. Chronic inflammation in COPD mainly involves the infiltration of neutrophils, macrophages, lymphocytes, and other inflammatory cells into the small airways. The contribution of resident airway structural cells to the inflammatory process is also important in COPD. Airway remodeling consists of detrimental changes in structural tissues and cells including airway wall thickening, epithelial metaplasia, goblet cell hypertrophy, and smooth muscle hyperplasia. Persistent airway inflammation might contribute to airway remodeling and small airway obstruction. However, the underlying mechanisms remain unclear. In this review, we will provide an overview of recent insights into the role of major immunoinflammatory cells in COPD airway remodeling.

Protective Effects of Anti-IL17 on Acute Lung Injury Induced by LPS in Mice

Introduction: T helper 17 (Th17) has been implicated in a variety of inflammatory lung and immune system diseases. However, little is known about the expression and biological role of IL-17 in acute lung injury (ALI). We investigated the mechanisms involved in the effect of anti-IL17 in a model of lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Methods: Mice were pre-treated with anti-IL17, 1h before saline/LPS intratracheal administration alongside non-treated controls and levels of exhaled nitric oxide (eNO), cytokine expression, extracellular matrix remodeling and oxidative stress, as well as immune cell counts in bronchoalveolar lavage fluid (BALF), and respiratory mechanics were assessed in lung tissue. Results: LPS instillation led to an increase in multiple cytokines, proteases, nuclear factor-κB, and Forkhead box P3 (FOXP3), eNO and regulators of the actomyosin cytoskeleton, the number of CD4+ and iNOS-positive cells as well as the number of neutrophils and macrophages in BALF, resistance and elastance of the respiratory system, ARG-1 gene expression, collagen fibers, and actin and 8-iso-PGF2α volume fractions. Pre-treatment with anti-IL17 led to a significant reduction in the level of all assessed factors. Conclusions: Anti-IL17 can protect the lungs from the inflammatory effects of LPS-induced ALI, primarily mediated by the reduced expression of cytokines and oxidative stress. This suggests that further studies using anti-IL17 in a treatment regime would be highly worthwhile.

MicroRNA-128 targeting RPN2 inhibits cell proliferation and migration through the Akt-p53-cyclin pathway in colorectal cancer cells

Colorectal cancer (CRC) is a malignancy with high metastatic rates. The mechanism of miR-128 on the regulation of Ribophorin-II (RPN2) in CRC cells was explored in the present study. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) or western blot analyses were conducted to detect miR-128 and RPN2 levels in tissues and cell lines. AmiR-128 overexpression model was constructed using miR-128 mimic transfection in HT29 CRC cells. Then, cell proliferation was detected using a Cell Counting Kit-8 assay, and the migratory and invasive abilities were measured by Transwell assay. RT-qPCR and western blot analysis were used to detect expression levels of protein kinase-B (Akt)-tumor protein 53 (p53)-cyclin pathway and metastasis-associated factors. In the present study, it was identified that aberrant decreased miR-128 was negatively correlated with RPN2 in CRC tissues. The increased RPN2 levels were significantly associated with poorly-differentiated histology, advanced stages and lymph nodes metastasis in patients with CRC. The survival rate of patients with CRC was also closely associated with RPN2 levels. In HT29 cells, miR-128 upregulation downregulated mRNA and protein levels of RPN2, and significantly inhibited cell proliferative, migratory and invasive abilities. Markedly decreased Akt phosphorylation and cyclin D1 levels and increased p53 levels were detected when cells were transfected with miR-128 mimics. Concurrently, decreased levels of matrix metalloproteinase (MMP)-2, MMP-9 and metastasis-associated protein 1, and increased levels of epithelial-cadherin and tissue inhibitor of metalloproteinases 2, were revealed in miR-128 mimic-transfected cells. Subsequent to screening with miRNA target prediction databases, the specificity of miR-128-targeted RPN2 was validated by a luciferase reporter assay. In conclusion, the results suggested that miR-128 was a specific negative regulator of RPN2, which regulated colorectal cancer cell proliferation and migration by affecting the Akt-p53-cyclin pathway. These data may provide novel evidence for the therapeutic potential of miR-128-based treatments for colorectal cancer.

The VP1 unique region of human parvovirus B19 and human bocavirus induce lung injury in naïve Balb/c mice

Both human parvovirus B19 (B19V) and human bocavirus (HBoV) are known to be important human pathogens of the Parvoviridae family. Our earlier investigation demonstrated that both B19V-VP1u and HBoV-VP1u have a significantly disruptive effect on tight junctions (TJs) in A549 cells, implying the essential role of parvovirus in airway infection and lung injury. However, no direct evidence that B19V-VP1u and HBoV-VP1u induce lung injury exists. The present study further investigates the induction of lung injury by B19V-VP1u and HBoV-VP1u in naïve Balb/c mice following subcutaneous injection of PBS, recombinant B19V-VP1u or HBoV-VP1u. The experimental results reveal significantly increased activity, protein expression and ratio of matrix metalloproteinase-9 (MMP-9) to MMP-2 in Balb/c mice that received B19V-VP1u or HBoV-VP1u compared to those that received PBS. Significantly higher levels of inflammatory cytokines, including IL-6 and IL-1β, and greater lymphocyte infiltration in lung tissue sections were detected in mice that received B19V-VP1u or HBoV-VP1u. Additionally, significantly increased levels of phosphorylated p65 (NF-κB) and MAPK signaling proteins were observed in lung tissue of mice that received B19V-VP1u or HBoV-VP1u compared to those of mice that received PBS. These findings demonstrate for the first time that B19V-VP1u and HBoV-VP1u proteins induce lung inflammatory reactions through p65 (NF-κB) and MAPK signaling.

Biomarkers of oxidative stress and protein-protein interaction in chronic obstructive pulmonary disease

CONTENT

The increased oxidative stress in chronic obstructive pulmonary disease (COPD) patients is the result of increased inhaled oxidants, generated by various cells of the airways.

OBJECTIVE

The investigation included measurements of malondiadehyde (MDA), uric acid, ascorbic acid, and matrix metalloproteinase-12 (MMP-12) in COPD patient. We also performed genetic analysis for protein-protein interaction (PPI) network.

MATERIALS AND METHODS

The study was conducted on healthy subjects with normal lung function (NS, 14 subjects) and 28 patients (Global Initiative for Chronic Obstructive Lung Disease (Gold) 1 and Gold 2) with COPD.

RESULTS

There was significant (p < .001) increase in MMP-12, MDA and uric acid levels as compared to healthy controls. A significant (p < .001) decline in ascorbic acid level was observed in COPD patients. The PPI was found to be 0.833 which indicated that proteins present in COPD are linked.

DISCUSSION AND CONCLUSION

This study suggests oxidative stress plays an important role in COPD and the PPI provide indication that proteins present in COPD are linked.

New insights into the mechanisms of pulmonary edema in acute lung injury

Appearance of alveolar protein-rich edema is an early event in the development of acute respiratory distress syndrome (ARDS). Alveolar edema in ARDS results from a significant increase in the permeability of the alveolar epithelial barrier, and represents one of the main factors that contribute to the hypoxemia in these patients. Damage of the alveolar epithelium is considered a major mechanism responsible for the increased pulmonary permeability, which results in edema fluid containing high concentrations of extravasated macromolecules in the alveoli. The breakdown of the alveolar-epithelial barrier is a consequence of multiple factors that include dysregulated inflammation, intense leukocyte infiltration, activation of pro-coagulant processes, cell death and mechanical stretch. The disruption of tight junction (TJ) complexes at the lateral contact of epithelial cells, the loss of contact between epithelial cells and extracellular matrix (ECM), and relevant changes in the communication between epithelial and immune cells, are deleterious alterations that mediate the disruption of the alveolar epithelial barrier and thereby the formation of lung edema in ARDS.

Matrix biomechanics and dynamics in pulmonary fibrosis

The composition and mechanical properties of the extracellular matrix are dramatically altered during the development and progression of pulmonary fibrosis. Recent evidence indicates that these changes in matrix composition and mechanics are not only end-results of fibrotic remodeling, but active participants in driving disease progression. These insights have stimulated interest in identifying the components and physical aspects of the matrix that contribute to cell activation and disease initiation and progression. This review summarizes current knowledge regarding the biomechanics and dynamics of the ECM in mouse models and human IPF, and discusses how matrix mechanical and compositional changes might be non-invasively assessed, therapeutically targeted, and biologically restored to resolve fibrosis.