Oxidative Stress and Therapeutic Development in Lung Diseases

Associations between ultrafine particle pollution and daily outpatient visits for respiratory diseases in Shanghai, China: a time-series analysis

Previous epidemiological studies have linked short-term exposure to particulate matter with outpatient visits for respiratory diseases. However, evidence on ultrafine particle (UFP) is still scarce in China. To investigate the association between short-term UFP exposure and outpatient visits for respiratory diseases as well as the corresponding lag patterns, information on outpatient visits for main respiratory diseases during January 1, 2017, to December 31, 2019 was collected from electronic medical records of two large tertiary hospitals in Shanghai, China. Generalized additive models employing a Quasi-Poisson distribution were employed to investigate the relationships between UFP and respiratory diseases. We computed the percentage change and its corresponding 95% confidence interval (CI) for outpatient visits related to respiratory diseases per interquartile range (IQR) increase in UFP concentrations. Based on a total of 1,034,394 hospital visits for respiratory diseases in Shanghai, China, we found that the strongest associations of total UFP with acute upper respiratory tract infection (AURTI), bronchitis, chronic obstructive pulmonary disease (COPD), and pneumonia occurred at lag 03, 03, 0, and 03 days, respectively. Each IQR increase in the total UFP concentrations was associated with increments of 9.02% (95% CI: 8.64-9.40%), 3.94% (95% CI: 2.84-5.06%), 4.10% (95% CI: 3.01-5.20%), and 10.15% (95% CI: 9.32-10.99%) for AURTI, bronchitis, COPD, and pneumonia, respectively. Almost linear concentration-response relationship curves without apparent thresholds were observed between total UFP and outpatient-department visits for four respiratory diseases. Stratified analyses illustrated significantly stronger associations of total UFP with AURTI, bronchitis, and pneumonia among female patients, while that with COPD was stronger among male patients. After adjustment of criteria air pollutants, these associations all remained robust. This time-series study indicates that short-term exposure to UFP was associated with increased risk of hospital visits for respiratory diseases, underscoring the importance of reducing ambient UFP concentrations for respiratory diseases control and prevention.

Ginsenoside Rg1 ameliorates hypoxia-induced pulmonary arterial hypertension by inhibiting endothelial-to-mesenchymal transition and inflammation by regulating CCN1

Pulmonary arterial hypertension (PAH) is a chronic obstructive disease characterized by vascular remodeling. Studies have confirmed that ginsenoside Rg1 can improve pulmonary hypertension to a certain extent, but the potential mechanism by which it improves hypoxia-induced PAH remains unclear. The aim of this study was to investigate the therapeutic effect of ginsenoside Rg1 on hypoxia-induced PAH. The results showed that hypoxia promoted inflammation, EndMT, and vascular remodeling, which were accompanied by decreased CCN1 levels and increased p-NFκB p65, TGF-β1, and p-Smad 2/3 levels. Treatment with ginsenoside Rg1, recombinant CCN1, BAY-11-7082, and SB-431542 could prevent hypoxia-induced vascular remodeling, reduce the expression of the hypoxia-induced inflammatory cytokines TNF-α and IL-1β, inhibit the expression of the mesenchymal markers α-SMA and Vimentin and restore the expression of the endothelial markers CD31 and VE-cadherin to improve hypoxia-induced EndMT, which may be associated with the upregulation of CCN1 protein expression and downregulation of p-NFκB p65, TGF-β1, and p-Smad 2/3 in rats and cells. siRNA CCN1 transfection increased the expression of p-NFκB p65, TGF-β1, and p-Smad 2/3 and accelerated the occurrence and development of inflammation and EndMT after hypoxia. In summary, our study indicated that hypoxia-induced EndMT and inflammation play a role in hypoxic pulmonary hypertension (HPH). Ginsenoside Rg1 treatment could reverse hypoxia-induced EndMT and inflammation by regulating CCN1 and has potential value in the prevention and treatment of HPH.

Oxidative stress stimulation leads to cell-specific oxidant and antioxidant responses in airway resident and inflammatory cells

AIMS

The imbalance between reactive oxygen species (ROS) and the antioxidant response has been linked to various airway diseases, including asthma. However, knowledge on cell-specific responses of the airway resident and inflammatory cells against increased oxidant stress is very limited. We aim to better understand the cell-specific antioxidant response that contributes to the pathophysiology of lung disease in response to oxidative stress.

MATERIALS AND METHODS

The human cell lines of epithelial, fibroblast, endothelial, monocyte, eosinophil and neutrophil were incubated with tert-butyl hydroperoxide (tBHP) or cigarette smoke condensate (CSC). Following stimulation, cell viability, total oxidant and antioxidant activity were assessed in both residential and inflammatory cells. Human Oxidative Stress Plus RT² Profiler PCR array was used to determine 84 gene expression differences in oxidant and antioxidant pathways following oxidant stimulus in all cells.

KEY FINDINGS

We showed that various cell types respond differently to oxidative stress inducers, with distinct gene expression and oxidant-antioxidant generation. Most importantly, eosinophils increased the activity of all main antioxidant enzymes in response to both oxidants. Monocytes, on the other hand, showed no change in response to each stimulation, whereas neutrophils only increased their CAT activity in response to both stimuli. The increase in NRF2-regulated genes HSPA1A, HMOX1 and DUSP1 after both tBHP and CSC in epithelial cells and fibroblasts indicates Nfr2 pathway activation.

SIGNIFICANCE

This study advances our knowledge of the molecular and cellular mechanisms of cell-specific antioxidant response upon exposure to oxidative stress. Additionally, our observations imply that the eosinophils' distinct biological response may be utilized for endotype-based cell-targeted antioxidant therapy.

N-acetylcysteine decreases lung inflammation and fibrosis by modulating ROS and Nrf2 in mice model exposed to particulate matter

Background and Objectives: Air pollutants can induce and incite airway diseases such as asthma. N-acetylcysteine (NAC) affects signaling pathways involved in apoptosis, angiogenesis, cell growth and arrest, redox-regulated gene expression, and the inflammatory response. However, it is not known how NAC change redox-regulated gene expression in asthma mouse model exposed to particulate matter (PM). To investigate the effects of NAC on asthma mice exposed to PM through Reactive oxygen species (ROS), nuclear factor erythroid 2-related factor 2 (Nrf2), and mucin 5 (Muc5).Methods: To investigate the effects of NAC (100 mg/kg) on redox-regulated gene expression and lung fibrosis in a mouse model of asthma exposed to PM. A mice model of asthma induced by ovalbumin (OVA) or OVA plus titanium dioxide (OVA + TiO₂) was established using wild-type BALB/c female mice, and the levels of Nrf2 and mucin 5AC (Muc5ac) proteins following NAC treatment were examined by Western blotting and immunostaining. In addition, the protein levels of ROS were checked.Results: Airway hyperresponsiveness and inflammation, goblet cell hyperplasia, and lung fibrosis were higher in OVA, OVA + TiO₂ mice than in control mice. NAC diminished OVA + TiO₂-induced airway hyperresponsiveness and inflammation, goblet cell hyperplasia, and lung fibrosis. Levels of ROS, Nrf2, and Muc5ac protein were higher in lung tissue from OVA + TiO₂ mice than that from control mice and were decreased by treatment with NAC.Conclusions: NAC reduce airway inflammation and responsiveness, goblet cell hyperplasia, and lung fibrosis by modulating ROS and Nrf2.

Maternal Exercise-Induced SOD3 Reverses the Deleterious Effects of Maternal High-Fat Diet on Offspring Metabolism Through Stabilization of H3K4me3 and Protection Against WDR82 Carbonylation

Preclinical studies reveal maternal exercise as a promising intervention to reduce the transmission of multigenerational metabolic dysfunction caused by maternal obesity. The benefits of maternal exercise on offspring health may arise from multiple factors and have recently been shown to involve DNA demethylation of critical hepatic genes leading to enhanced glucose metabolism in offspring. Histone modification is another epigenetic regulator, yet the effects of maternal obesity and exercise on histone methylation in offspring are not known. Here, we find that maternal high-fat diet (HFD; 60% kcal from fat) induced dysregulation of offspring liver glucose metabolism in C57BL/6 mice through a mechanism involving increased reactive oxygen species, WD repeat-containing 82 (WDR82) carbonylation, and inactivation of histone H3 lysine 4 (H3K4) methyltransferase leading to decreased H3K4me3 at the promoters of glucose metabolic genes. Remarkably, the entire signal was restored if the HFD-fed dams had exercised during pregnancy. WDR82 overexpression in hepatoblasts mimicked the effects of maternal exercise on H3K4me3 levels. Placental superoxide dismutase 3 (SOD3), but not antioxidant treatment with N-acetylcysteine was necessary for the regulation of H3K4me3, gene expression, and glucose metabolism. Maternal exercise regulates a multicomponent epigenetic system in the fetal liver resulting in the transmission of the benefits of exercise to offspring.

Immune Repertoire and Advancements in Nanotherapeutics for the Impediment of Severe Steroid Resistant Asthma (SSR)

Severe steroid-resistant asthma (SSR) patients do not respond to the corticosteroid therapies due to the heterogeneity, and genome-wide variations. However, there are very limited reports pertinent to the molecular signaling underlying SSR and making pharmacologists, and formulation scientists to identify the effective therapeutic targets in order to produce novel therapies using novel drug delivery systems (NDDS). We have substantially searched literature for the peer-reviewed and published reports delineating the role of glucocorticoid-altered gene expression, and the mechanisms responsible for SSR asthma, and NDDS for treating SSR asthma using public databases PubMed, National Library of Medicine (NLM), google scholar, and medline. Subsequently, we described reports underlying the SSR pathophysiology through several immunological and inflammatory phenotypes. Furthermore, various therapeutic strategies and the role of signaling pathways such as mORC1-STAT3-FGFBP1, NLRP3 inflammasomes, miR-21/PI3K/HDAC2 axis, PI3K were delineated and these can be considered as the therapeutic targets for mitigating the pathophysiology of SSR asthma. Finally, the possibility of nanomedicine-based formulation and their applications in order to enhance the long term retention of several antioxidant and anti-asthmatic drug molecules as a significant therapeutic modality against SSR asthma was described vividly.

Mitochondria signaling pathways in allergic asthma

Mitochondria, as the powerhouse organelle of cells, are greatly involved in regulating cell signaling pathways, including those related to the innate and acquired immune systems, cellular differentiation, growth, death, apoptosis, and autophagy as well as hypoxic stress responses in various diseases. Asthma is a chronic complicated airway disease characterized by airway hyperresponsiveness, eosinophilic inflammation, mucus hypersecretion, and remodeling of airway. The asthma mortality and morbidity rates have increased worldwide, so understanding the molecular mechanisms underlying asthma progression is necessary for new anti-asthma drug development. The lung is an oxygen-rich organ, and mitochondria, by sensing and processing O2, contribute to the generation of ROS and activation of pro-inflammatory signaling pathways. Asthma pathophysiology has been tightly associated with mitochondrial dysfunction leading to reduced ATP synthase activity, increased oxidative stress, apoptosis induction, and abnormal calcium homeostasis. Defects of the mitochondrial play an essential role in the pro-remodeling mechanisms of lung fibrosis and airway cells' apoptosis. Identification of mitochondrial therapeutic targets can help repair mitochondrial biogenesis and dysfunction and reverse related pathological changes and lung structural remodeling in asthma. Therefore, we here overviewed the relationship between mitochondrial signaling pathways and asthma pathogenic mechanisms.

Overview on Interactive Role of Inflammation, Reactive Oxygen Species, and Calcium Signaling in Asthma, COPD, and Pulmonary Hypertension

Inflammatory signaling is a major component in the development and progression of many lung diseases, including asthma, chronic obstructive pulmonary disorder (COPD), and pulmonary hypertension (PH). This chapter will provide a brief overview of asthma, COPD, and PH and how inflammation plays a vital role in these diseases. Specifically, we will discuss the role of reactive oxygen species (ROS) and Ca²⁺ signaling in inflammatory cellular responses and how these interactive signaling pathways mediate the development of asthma, COPD, and PH. We will also deliberate the key cellular responses of pulmonary arterial (PA) smooth muscle cells (SMCs) and airway SMCs (ASMCs) in these devastating lung diseases. The analysis of the importance of inflammation will shed light on the key questions remaining in this field and highlight molecular targets that are worth exploring. The crucial findings will not only demonstrate the novel roles of essential signaling molecules such as Rieske iron-sulfur protein and ryanodine receptor in the development and progress of asthma, COPD, and PH but also offer advanced insight for creating more effective and new therapeutic targets for these devastating inflammatory lung diseases.

Etomidate attenuates hyperoxia-induced acute lung injury in mice by modulating the Nrf2/HO-1 signaling pathway

The present study aimed to investigate the protective effects of etomidate on hyperoxia-induced acute lung injury in mice, particularly on the nuclear factor-erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. Fifty specific pathogen-free mice were randomly divided into the blank control, model, high oxygen exposure + low etomidate dose (0.3 mg·kg^-1), a high oxygen exposure + moderate etomidate dose (3 mg·kg^-1), and a high oxygen exposure + high etomidate dose (10 mg·kg^-1) groups, with ten mice allotted per group. After 72 h, the mice were sacrificed and the lung tissues were harvested, and the wet-to-dry (W/D) ratio of the tissues was calculated. Hematoxylin-eosin staining was performed to observe the pathological changes in the lung tissues, and the lung injury score (LIS) was calculated. The mRNA and protein expression levels of Nrf2 and HO-1 were measured. The malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD) and catalase (CAT) levels were also measured, and interleukin (IL)-1β, IL-6, tumor necrosis factor alpha (TNF-α) and IL-10 concentrations in the bronchoalveolar lavage fluid were determined. At low and moderate doses, etomidate decreased pathological damage in the lung tissue, decreased the LIS and W/D ratio, upregulated Nrf2 and HO-1 mRNA and protein expression, decreased IL-1β, IL-6, and TNF-α concentrations, increased MPO activity and IL-10 levels, suppressed the production of the oxidation product MDA, and enhanced the activities of the antioxidant enzymes CAT and SOD. Within a certain dose range, etomidate enhanced antioxidant and anti-inflammatory effects in mice, thereby decreasing lung injury induced by the chronic inhalation of oxygen at high concentrations. Furthermore, the underlying mechanism may be associate with the upregulation of the Nrf2/HO-1 signaling pathway.

Acute Radiation Syndrome and the Microbiome: Impact and Review

Study of the human microbiota has been a centuries-long endeavor, but since the inception of the National Institutes of Health (NIH) Human Microbiome Project in 2007, research has greatly expanded, including the space involving radiation injury. As acute radiation syndrome (ARS) is multisystemic, the microbiome niches across all areas of the body may be affected. This review highlights advances in radiation research examining the effect of irradiation on the microbiome and its potential use as a target for medical countermeasures or biodosimetry approaches, or as a medical countermeasure itself. The authors also address animal model considerations for designing studies, and the potential to use the microbiome as a biomarker to assess radiation exposure and predict outcome. Recent research has shown that the microbiome holds enormous potential for mitigation of radiation injury, in the context of both radiotherapy and radiological/nuclear public health emergencies. Gaps still exist, but the field is moving forward with much promise.

NF-κB and FosB mediate inflammation and oxidative stress in the blast lung injury of rats exposed to shock waves

Blast lung injury (BLI) is the major cause of death in explosion-derived shock waves; however, the mechanisms of BLI are not well understood. To identify the time-dependent manner of BLI, a model of lung injury of rats induced by shock waves was established by a fuel air explosive. The model was evaluated by hematoxylin and eosin staining and pathological score. The inflammation and oxidative stress of lung injury were also investigated. The pathological scores of rats' lung injury at 2 h, 24 h, 3 days, and 7 days post-blast were 9.75±2.96, 13.00±1.85, 8.50±1.51, and 4.00±1.41, respectively, which were significantly increased compared with those in the control group (1.13±0.64; P<0.05). The respiratory frequency and pause were increased significantly, while minute expiratory volume, inspiratory time, and inspiratory peak flow rate were decreased in a time-dependent manner at 2 and 24 h post-blast compared with those in the control group. In addition, the expressions of inflammatory factors such as interleukin (IL)-6, IL-8, FosB, and NF-κB were increased significantly at 2 h and peaked at 24 h, which gradually decreased after 3 days and returned to normal in 2 weeks. The levels of total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase were significantly decreased 24 h after the shock wave blast. Conversely, the malondialdehyde level reached the peak at 24 h. These results indicated that inflammatory and oxidative stress induced by shock waves changed significantly in a time-dependent manner, which may be the important factors and novel therapeutic targets for the treatment of BLI.

Novel drug delivery systems targeting oxidative stress in chronic obstructive pulmonary disease: a review

Oxidative stress is significantly involved in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). Combining antioxidant drugs or nutrients results in a noteworthy therapeutic value in animal models of COPD. However, the benefits have not been reproduced in clinical applications, this may be attributed to the limited absorption, concentration, and half-life of exogenous antioxidants. Therefore, novel drug delivery systems to combat oxidative stress in COPD are needed. This review presents a brief insight into the current knowledge on the role of oxidative stress and highlights the recent trends in novel drug delivery carriers that could aid in combating oxidative stress in COPD. The introduction of nanotechnology has enabled researchers to overcome several problems and improve the pharmacokinetics and bioavailability of drugs. Large porous microparticles, and porous nanoparticle-encapsulated microparticles are the most promising carriers for achieving effective pulmonary deposition of inhaled medication and obtaining controlled drug release. However, translating drug delivery systems for administration in pulmonary clinical settings is still in its initial phases.

Bioactive structural basis of proteoglycans from Sarcandra glabra based on spectrum-effect relationship

ETHNOPHARMACOLOGICAL RELEVANCE

Proteoglycans are one of the active ingredients of great importance in Sarcandra glabra. The biological activities of proteoglycans extracted from Sarcandra glabra including suppressing tumor growth and antioxidant activity were studied. However, raw materials from different regions may cause differences in the activity of natural extracts, especially for bioactive biomacromolecules. Conventional identification of S.glabra cannot accurately reflect the distinguishing relationship between internal components and the pharmacological activity. The identification of biologically active structures was obtained by constructing multiple fingerprint and spectrum-effect relationship.

AIM OF THE STUDY

To evaluate the bioactive structural basis of proteoglycans from S.glabra based on spectrum-effect relationship and chemometric methods.

MATERIALS AND METHODS

Multiple fingerprinting including HPSEC, PMP-HPLC, and FT-IR of proteoglycans was established from 18 batches of samples based on the structural characteristics. Both antitumor activity and antioxidant activity were determined. Mathematical analysis was used to analyze the spectrum-effect relationship.

RESULTS

PCA results showed monosaccharides including Xly, Rha, and GlcA, carboxyl group in acidic sugars, peptide bond in proteins, and methylene groups could be used as markers for distinguishing the samples from different sources. The results of the spectrum-effect relationship analysis indicated that the bioactive markers of inhibitory activity on MG63 and U2OS cells by PLS-DA were related to GlcA, Xyl, Fuc, β-glycosidic bonds, peptide linkage, and methylene groups. Markers composing monosaccharide for antioxidant activity were Xyl, GlcA, and GlcN. Meanwhile, the group markers were pyranose ring, carboxyl group, peptide linkage, and methylene structure.

CONCLUSIONS

The material basis that affects the pharmacological efficacy could be found according to the spectrum-effect relationship analysis. This study could lay a foundation for further exploring the relationship between structural characteristics and pharmacodynamics of macromolecular glycoconjugates in Traditional Chinese Medicine.

Biomarkers of Oxidative Stress and Inflammation in Chronic Airway Diseases

Introduction: The global burden of chronic airway diseases represents an important public health concern. The role of oxidative stress and inflammation in the pathogenesis of these diseases is well known. The aim of this study is to evaluate the behavior of both inflammatory and oxidative stress biomarkers in patients with chronic bronchitis, current asthma and past asthma in the frame of a population-based study. Methods: For this purpose, data collected from the Gene Environment Interactions in Respiratory Diseases (GEIRD) Study, an Italian multicentre, multicase-control study, was evaluated. Cases and controls were identified through a two-stage screening process of individuals aged 20-65 years from the general population. Out of 16,569 subjects selected from the general population in the first stage of the survey, 2259 participated in the clinical evaluation. Oxidative stress biomarkers such as 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), 8-isoprostane and glutathione and inflammatory biomarkers such as Fractional Exhaled Nitric Oxide (FENO) and white blood cells were evaluated in 1878 subjects. Results: Current asthmatics presented higher levels of FENO (23.05 ppm), leucocytes (6770 n/µL), basophils (30.75 n/µL) and eosinophils (177.80 n/µL), while subjects with chronic bronchitis showed higher levels of GSH (0.29 mg/mL) and lymphocytes (2101.6 n/µL). The multivariable multinomial logistic regression confirmed high levels of leucocytes (RRR = 1.33), basophils (RRR = 1.48), eosinophils (RRR = 2.39), lymphocytes (RRR = 1.26) and FENO (RRR = 1.42) in subjects with current asthma. Subjects with past asthma had a statistically significant higher level of eosinophils (RRR = 1.78) with respect to controls. Subjects with chronic bronchitis were characterized by increased levels of eosinophils (RRR = 2.15), lymphocytes (RRR = 1.58), GSH (RRR = 2.23) and 8-isoprostane (RRR = 1.23). Conclusion: In our study, current asthmatics show a greater expression of the inflammatory profile compared to subjects who have had asthma in the past and chronic bronchitis. On the other hand, chronic bronchitis subjects showed a higher rate of expression of oxidative stress biomarkers compared to asthmatic subjects. In particular, inflammatory markers such as circulating inflammatory cells and FENO seem to be more specific for current asthma, while oxidative stress biomarkers such as glutathione and 8-isoprostane appear to be more specific and applicable to patients with chronic bronchitis.

MicroRNA regulation postbleomycin due to the R213G extracellular superoxide dismutase variant is predicted to suppress inflammatory and immune pathways

Oxidative stress is a key contributor to the development of dysregulated inflammation in acute lung injury (ALI). A naturally occurring single nucleotide polymorphism in the key extracellular antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), results in an arginine to glycine substitution (R213G) that promotes resolution of inflammation and protection against bleomycin-induced ALI. Previously we found that mice harboring the R213G mutation in EC-SOD exhibit a transcriptomic profile consistent with a striking suppression of inflammatory and immune pathways 7 days postbleomycin. However, the alterations in noncoding regulatory RNAs in wild-type (WT) and R213G EC-SOD lungs have not been examined. Therefore, we used next-generation microRNA (miR) Sequencing of lung tissue to identify dysregulated miRs 7 days after bleomycin in WT and R213G mice. Differential expression analysis identified 92 WT and 235 R213G miRs uniquely dysregulated in their respective genotypes. Subsequent pathway analysis identified that these miRs were predicted to regulate approximately half of the differentially expressed genes previously identified. The gene targets of these altered miRs indicate suppression of immune and inflammatory pathways in the R213G mice versus activation of these pathways in WT mice. Triggering receptor expressed on myeloid cells 1 (TREM1) signaling was identified as the inflammatory pathway with the most striking difference between WT and R213G lungs. miR-486b-3p was identified as the most dysregulated miR predicted to regulate the TREM1 pathway. We validated the increase in TREM1 signaling using miR-486b-3p antagomir transfection. These findings indicate that differential miR regulation is predicted to regulate the inflammatory gene profile, contributing to the protection against ALI in R213G mice.

Mechanisms of ultrafine particle-induced respiratory health effects

Particulate matter (PM) is the principal component of air pollution. PM includes a range of particle sizes, such as coarse, fine, and ultrafine particles. Particles that are <100 nm in diameter are defined as ultrafine particles (UFPs). UFPs are found to a large extent in urban air as both singlet and aggregated particles. UFPs are classified into two major categories based on their source. Typically, UFPs are incidentally generated in the environment, often as byproducts of fossil fuel combustion, condensation of semivolatile substances or industrial emissions, whereas nanoparticles are manufactured through controlled engineering processes. The primary exposure mechanism of PM is inhalation. Inhalation of PM exacerbates respiratory symptoms in patients with chronic airway diseases, but the mechanisms underlying this response remain unclear. This review offers insights into the mechanisms by which particles, including UFPs, influence airway inflammation and discusses several mechanisms that may explain the relationship between particulate air pollutants and human health, particularly respiratory health. Understanding the mechanisms of PM-mediated lung injury will enhance efforts to protect at-risk individuals from the harmful health effects of air pollutants.

Phycocyanin Ameliorates Radiation-Induced Acute Intestinal Toxicity by Regulating the Effect of the Gut Microbiota on the TLR4/Myd88/NF-κB Pathway

BACKGROUND

Radiation-induced gastrointestinal syndrome, including nausea, diarrhea, and dehydration, contributes to morbidity and mortality after medical or industrial radiation exposure, which seriously affects patient quality of life after treatment. No safe and effective radiation countermeasure has been approved for clinical therapy. In this study, we aimed to investigate the potential protective effects of phycocyanin (PC) against radiation-induced acute intestinal injury.

MATERIALS AND METHODS

C57BL/6 mice were orally administered 50 mg/kg PC once per day for 1 month before exposure to total-abdominal x-ray irradiation at a single dose of 12 Gy. The effects of PC on intestinal histopathology and integrity, gut microbiota, lipopolysaccharides (LPS), inflammatory cytokines, and Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (Myd88)/nuclear factor κB (NF-κB) signaling were evaluated.

RESULTS

Severe histopathological damage, such as intestinal mucosal epithelial cell apoptosis, necrosis, and nuclear rupture, was most clearly observed 24 hours after total-abdominal x-ray irradiation. Intestinal integrity was damaged by irradiation, which manifested in reduced levels of the tight-junction proteins Claudin-1, Occludin, and zonula occludens-1(ZO-1). PC pretreatment significantly ameliorated radiation-induced intestinal injury. PC also modulated the gut microbiota composition, increasing the proportion of beneficial bacteria and decreasing that of harmful bacteria, which in turn lowered LPS levels and suppressed TLR4/Myd88/NF-κB pathway activation. Finally, levels of corresponding inflammatory cytokines, including tumor necrosis factor α and interleukin-6, were also downregulated.

CONCLUSION

PC protects against mouse intestinal injury from high-dose radiation by regulating the effect of the gut microbiota on the TLR4/Myd88/NF-κB pathway, suggesting PC as a promising natural radiation countermeasure.

Involvement of the Prion Protein in the Protection of the Human Bronchial Epithelial Barrier Against Oxidative Stress

Aim: Bronchial epithelium acts as a defensive barrier against inhaled pollutants and microorganisms. This barrier is often compromised in inflammatory airway diseases that are characterized by excessive oxidative stress responses, leading to bronchial epithelial shedding, barrier failure, and increased bronchial epithelium permeability. Among proteins expressed in the junctional barrier and participating to the regulation of the response to oxidative and to environmental stresses is the cellular prion protein (PrP^C). However, the role of PrP^C is still unknown in the bronchial epithelium. Herein, we investigated the cellular mechanisms by which PrP^C protein participates into the junctional complexes formation, regulation, and oxidative protection in human bronchial epithelium. Results: Both PrP^C messenger RNA and mature protein were expressed in human epithelial bronchial cells. PrP^C was localized in the apical domain and became lateral, at high degree of cell polarization, where it colocalized and interacted with adherens (E-cadherin/γ-catenin) and desmosomal (desmoglein/desmoplakin) junctional proteins. No interaction was detected with tight junction proteins. Disruption of such interactions induced the loss of the epithelial barrier. Moreover, we demonstrated that PrP^C protection against copper-associated oxidative stress was involved in multiple processes, including the stability of adherens and desmosomal junctional proteins. Innovation: PrP^C is a pivotal protein in the protection against oxidative stress that is associated with the degradation of adherens and desmosomal junctional proteins. Conclusion: Altogether, these results demonstrate that the loss of the integrity of the epithelial barrier by oxidative stress is attenuated by the activation of PrP^C expression, where deregulation might be associated with respiratory diseases.

Delivery of natural phenolic compounds for the potential treatment of lung cancer

The application of natural products to treat various diseases, such as cancer, has been an important area of research for many years. Several phytochemicals have demonstrated anticarcinogenic activity to prevent or reduce the progression of cancer by modulating various cellular mechanisms. However, poor bioavailability has hindered clinical success and the incorporation of these drugs into efficient drug delivery systems would be beneficial. For lung cancer, local delivery via the pulmonary route would also be more effective. In this article, recent in vitro scientific literature on phenolic compounds with anticancer activity towards lung cancer cell lines is reviewed and nanoparticulate delivery is mentioned as a possible solution to the problem of bioavailability. The first part of the review will explore the different classes of natural phenolic compounds and discuss recent reports on their activity on lung cancer cells. Then, the problem of the poor bioavailability of phenolic compounds will be explored, followed by a summary of recent advances in improving the efficacy of these phenolic compounds using nanoparticulate drug delivery systems. Graphical abstract The rationale for direct delivery of phenolic compounds loaded in microparticles to the lungs.

Increasing complexity and interactions of oxidative stress in chronic respiratory diseases: An emerging need for novel drug delivery systems

Oxidative stress is intensely involved in enhancing the severity of various chronic respiratory diseases (CRDs) including asthma, chronic obstructive pulmonary disease (COPD), infections and lung cancer. Even though there are various existing anti-inflammatory therapies, which are not enough to control the inflammation caused due to various contributing factors such as anti-inflammatory genes and antioxidant enzymes. This leads to an urgent need of novel drug delivery systems to combat the oxidative stress. This review gives a brief insight into the biological factors involved in causing oxidative stress, one of the emerging hallmark feature in CRDs and particularly, highlighting recent trends in various novel drug delivery carriers including microparticles, microemulsions, microspheres, nanoparticles, liposomes, dendrimers, solid lipid nanocarriers etc which can help in combating the oxidative stress in CRDs and ultimately reducing the disease burden and improving the quality of life with CRDs patients. These carriers improve the pharmacokinetics and bioavailability to the target site. However, there is an urgent need for translational studies to validate the drug delivery carriers for clinical administration in the pulmonary clinic.

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.

R213G polymorphism in SOD3 protects against bleomycin-induced inflammation and attenuates induction of proinflammatory pathways

Extracellular superoxide dismutase (EC-SOD), one of three mammalian SOD isoforms, is the sole extracellular enzymatic defense against superoxide. A known human single nucleotide polymorphism (SNP) in the matrix-binding domain of EC-SOD characterized by an arginine-to-glycine substitution at position 213 (R213G) redistributes EC-SOD from the matrix into extracellular fluids. We previously reported that knock-in mice harboring the human R213G SNP (R213G mice) exhibited enhanced resolution of inflammation with subsequent protection against fibrosis following bleomycin treatment compared with wild-type (WT) littermates. Herein we set out to determine the underlying pathways with RNA-Seq analysis of WT and R213G lungs 7 days post-PBS and bleomycin. RNA-Seq analysis uncovered significant differential gene expression changes induced in WT and R213G strains in response to bleomycin. Ingenuity Pathways Analysis was used to predict differentially regulated up- and downstream processes based on transcriptional changes. Most prominent was the induction of inflammatory and immune responses in WT mice, which were suppressed in the R213G mice. Specifically, PKC signaling in T lymphocytes, IL-6, and NFΚB signaling were opposed in WT mice when compared with R213G. Several upstream regulators such as IFNγ, IRF3, and IKBKG were implicated in the divergent responses between WT and R213G mice. Our data suggest that the redistributed EC-SOD due to the R213G SNP attenuates the dysregulated inflammatory responses observed in WT mice. We speculate that redistributed EC-SOD protects against dysregulated alveolar inflammation via reprogramming of recruited immune cells toward a proresolving state.

Oxidative stress and imbalance of serum trace mineral metabolism contribute to bovine respiratory disease in dairy calves

Bovine respiratory disease (BRD) is the most common infectious cause of clinical disease and death in young calves. The study was undertaken to scrutinize a relationship between tissue damage by oxidative stress, concentrations of serum trace minerals and clinical status of calves during BRD. The method of clinical scoring and thoracic auscultation were used to screen and select infected calves. In this study, comparison of lipid peroxides (LPO), antioxidant enzymes and serum trace minerals was done between BRD infected and healthy subjects (18 calves in each group). The infected group was further divided into 3 subgroups according to clinical scores (CS) (5,6,7). The blood LPO levels were significantly higher in BRD infected calves. The antioxidative activities of superoxide dismutase, reduced glutathione, catalase and serum uric acid were significantly lower in BRD infected calves. The concentrations of trace minerals (copper, zinc, selenium) were significantly reduced during BRD. All hematobiochemical parameters varied proportionately with the CS of infected calves. These findings demonstrated simultaneous occurrence of increased oxidative stress and depletion of antioxidative trace minerals during BRD in calves. A strong correlation exists between severity of oxidative stress and CS of calves.

Reactive Oxygen Species, Biomarkers of Microvascular Maturation and Alveolarization, and Antioxidants in Oxidative Lung Injury

The lungs of extremely low gestational age neonates (ELGANs) are deficient in pulmonary surfactant and are incapable of efficient gas exchange necessary for successful transition from a hypoxic intrauterine environment to ambient air. To improve gas exchange and survival, ELGANs often receive supplemental oxygen with mechanical ventilation which disrupts normal lung developmental processes, including microvascular maturation and alveolarization. Factors that regulate these developmental processes include vascular endothelial growth factor and matrix metalloproteinases, both of which are influenced by generation of oxygen byproducts, or reactive oxygen species (ROS). ELGANs are also deficient in antioxidants necessary to scavenge excessive ROS. Thus, the accumulation of ROS in the preterm lungs exposed to prolonged hyperoxia, results in inflammation and development of bronchopulmonary dysplasia (BPD), a form of chronic lung disease (CLD). Despite advances in neonatal care, BPD/CLD remains a major cause of neonatal morbidity and mortality. The underlying mechanisms are not completely understood, and the benefits of current therapeutic interventions are limited. The association between ROS and biomarkers of microvascular maturation and alveolarization, as well as antioxidant therapies in the setting of hyperoxia-induced neonatal lung injury are reviewed in this article.

Mechanisms and consequences of oxidative stress in lung disease: therapeutic implications for an aging populace

The rapid expansion of the elderly population has led to the recent epidemic of age-related diseases, including increased incidence and mortality of chronic and acute lung diseases. Numerous studies have implicated aging and oxidative stress in the pathogenesis of various pulmonary diseases; however, despite recent advances in these fields, the specific contributions of aging and oxidative stress remain elusive. This review will discuss the consequences of aging on lung morphology and physiology, and how redox imbalance with aging contributes to lung disease susceptibility. Here, we focus on three lung diseases for which aging is a significant risk factor: acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). Preclinical and clinical development for redox- and senescence-altering therapeutic strategies are discussed, as well as scientific advancements that may direct current and future therapeutic development. A deeper understanding of how aging impacts normal lung function, redox balance, and injury-repair processes will inspire the development of new therapies to prevent and/or reverse age-associated pulmonary diseases, and ultimately increase health span and longevity. This review is intended to encourage basic, clinical, and translational research that will bridge knowledge gaps at the intersection of aging, oxidative stress, and lung disease to fuel the development of more effective therapeutic strategies for lung diseases that disproportionately afflict the elderly.

A novel fine tuning scheme of miR-200c in modulating lung cell redox homeostasis

Oxidative stress induces miR-200c, the predominant microRNA (miRNA) in lung tissues; however, the antioxidant role and biochemistry of such induction have not been clearly defined. Therefore, a lung adenocarcinoma cell line (A549) and a normal lung fibroblast (MRC-5) were used as models to determine the effects of miR-200c expression on lung antioxidant response. Hydrogen peroxide (H₂O₂) upregulated miR-200c, whose overexpression exacerbated the decrease in cell proliferation, retarded the progression of cells in the G2/M-phase, and increased oxidative stress upon H₂O₂ stimulation. The expression of three antioxidant proteins, superoxide dismutase (SOD)-2, haem oxygenase (HO)-1, and sirtuin (SIRT) 1, was reduced upon H₂O₂ stimulation in miR-200c-overexpressed A549 cells. This phenomenon of increased oxidative stress and antioxidant protein downregulation also occurs simultaneously in miR-200c overexpressed MRC-5 cells. Molecular analysis revealed that miR-200c inhibited the gene expression of HO-1 by directly targeting its 3'-untranslated region. The downregulation of SOD2 and SIRT1 by miR-200c was mediated through zinc finger E-box-binding homeobox 2 (ZEB2) and extracellular signal-regulated kinase 5 (ERK5) pathways, respectively, where knockdown of ZEB2 or ERK5 decreased the expression of SOD2 or SIRT1 in A549 cells. LNA anti-miR-200c transfection in A549 cells inhibited the endogenous miR-200c expression, resulting in increased expressions of antioxidant proteins, reduced oxidative stress and recovered cell proliferation upon H₂O₂ stimulation. These findings indicate that miR-200c fine-tuned the antioxidant response of the lung cells to oxidative stress through several pathways, and thus this study provides novel information concerning the role of miR-200c in modulating redox homeostasis of lung.

Role of the Nrf2/HO-1 axis in bronchopulmonary dysplasia and hyperoxic lung injuries

Bronchopulmonary dysplasia (BPD) is a chronic illness that usually originates in preterm newborns. Generally, BPD is a consequence of respiratory distress syndrome (RDS) which, in turn, comes from the early arrest of lung development and the lack of pulmonary surfactant. The need of oxygen therapy to overcome premature newborns' compromised respiratory function generates an increasing amount of reactive oxygen species (ROS), the onset of sustained oxidative stress (OS) status, and inflammation in the pulmonary alveoli deputies to respiratory exchanges. BPD is a severe and potentially life-threatening disorder that in the most serious cases, can open the way to neurodevelopmental delay. More importantly, there is no adequate intervention to hamper or treat BPD. This perspective article seeks to review the most recent and relevant literature describing the very early stages of BPD and hyperoxic lung injuries focussing on nuclear factor erythroid derived 2 (Nrf2)/heme oxygenase-1 (HO-1) axis. Indeed, Nrf2/HO1 activation in response to OS induced lung injury in preterm concurs to the induction of certain number of antioxidant, anti-inflammatory, and detoxification pathways that seem to be more powerful than the activation of one single antioxidant gene. These elicited protective effects are able to counteract/mitigate all multifaceted aspects of the disease and may support novel approaches for the management of BPD.

Inhalation Injury: Pathophysiology, Diagnosis, and Treatment

The classic determinants of mortality from severe burn injury are age, size of injury, delays of resuscitation, and the presence of inhalation injury. Of the major determinants of mortality, inhalation injury remains one of the most challenging injuries for burn care providers. Patients with inhalation injury are at increased risk for pneumonia (the leading cause of death) and multisystem organ failure. There is no consensus among leading burn care centers in the management of inhalation injury. This article outlines the current treatment algorithms and the evidence of their efficacy.

Mitochondrial Dysfunction in Airway Disease

There is increasing appreciation that mitochondria serve cellular functions beyond oxygen sensing and energy production. Accordingly, it has become important to explore noncanonical roles of mitochondria in normal and pathophysiological processes that influence airway structure and function in the context of diseases such as asthma and COPD. Mitochondria can sense upstream processes such as inflammation, infection, tobacco smoke, and environmental insults important in these diseases and in turn can respond to such stimuli through altered mitochondrial protein expression, structure, and resultant dysfunction. Conversely, mitochondrial dysfunction has downstream influences on cytosolic and mitochondrial calcium regulation, airway contractility, gene and protein housekeeping, responses to oxidative stress, proliferation, apoptosis, fibrosis, and certainly metabolism, which are all key aspects of airway disease pathophysiology. Indeed, mitochondrial dysfunction is thought to play a role even in normal processes such as aging and senescence and in conditions such as obesity, which impact airway diseases. Thus, understanding how mitochondrial structure and function play central roles in airway disease may be critical for the development of novel therapeutic avenues targeting dysfunctional mitochondria. In this case, it is likely that mitochondria of airway epithelium, smooth muscle, and fibroblasts play differential roles, consistent with their contributions to disease biology, underlining the challenge of targeting a ubiquitous cellular element of existential importance. This translational review summarizes the current state of understanding of mitochondrial processes that play a role in airway disease pathophysiology and identifying areas of unmet research need and opportunities for novel therapeutic strategies.