Growth factors in lung development and disease: friends or foe?

Liquid application dosing alters the physiology of air-liquid interface (ALI) primary human bronchial epithelial cell/lung fibroblast co-cultures and in vitro testing relevant endpoints

Differentiated primary human bronchial epithelial cell (dpHBEC) cultures grown under air-liquid interface (ALI) conditions exhibit key features of the human respiratory tract and are thus critical for respiratory research as well as efficacy and toxicity testing of inhaled substances (e.g., consumer products, industrial chemicals, and pharmaceuticals). Many inhalable substances (e.g., particles, aerosols, hydrophobic substances, reactive substances) have physiochemical properties that challenge their evaluation under ALI conditions in vitro. Evaluation of the effects of these methodologically challenging chemicals (MCCs) in vitro is typically conducted by "liquid application," involving the direct application of a solution containing the test substance to the apical, air-exposed surface of dpHBEC-ALI cultures. We report that the application of liquid to the apical surface of a dpHBEC-ALI co-culture model results in significant reprogramming of the dpHBEC transcriptome and biological pathway activity, alternative regulation of cellular signaling pathways, increased secretion of pro-inflammatory cytokines and growth factors, and decreased epithelial barrier integrity. Given the prevalence of liquid application in the delivery of test substances to ALI systems, understanding its effects provides critical infrastructure for the use of in vitro systems in respiratory research as well as in the safety and efficacy testing of inhalable substances.

Cadmium-induced Carcinogenesis in Respiratory Organs and the Prostate: Insights from Three Perspectives on Toxicogenomic Approach

Cadmium (Cd) exposure primarily occurs through inhalation, either by smoking or occupational exposure to contaminated air. Upon inhalation, Cd ultimately reaches the prostate through the bloodstream. In this review, we investigate the carcinogenic potential of Cd in both respiratory organs and the prostate. Specifically, this review examines cellular metabolism, comprehensive toxicity, and carcinogenic mechanisms by exploring gene ontology, biological networks, and adverse outcome pathways. In the respiratory organs, Cd induces lung cancer by altering the expression of IL1B and FGF2, causing DNA damage, reducing cell junction integrity, and promoting apoptosis. In the prostate, Cd induces prostate cancer by modifying the expression of EDN1 and HMOX1, leading to abnormal protein activities and maturation, suppressing tumor suppressors, and inducing apoptosis. Collectively, this review provides a comprehensive understanding of the carcinogenic mechanisms of Cd in two different organs by adopting toxicogenomic approaches. These insights can serve as a foundation for further research on cadmium-induced cancer, contributing to the establishment of future cancer prevention strategies.

Assessment of fetal pulmonary artery Doppler indices in pregnant women with rheumatoid arthritis and ankylosing spondylitis

PURPOSE

To investigate fetal pulmonary artery Doppler parameters in pregnant women with rheumatoid arthritis (RA) and ankylosing spondylitis (AS).

METHODS

This case-control study included 24 pregnant women diagnosed with 13 AS and 11 RA and 48 healthy pregnant women at 29-30 weeks of gestation. The demographic and clinical features were recorded, including disease type and duration, attacks during pregnancy, and medications. Pulmonary artery acceleration time (AT), ejection time (ET), and pulmonary artery acceleration time to ejection time (PATET) ratio were measured by manual trace with spectral Doppler ultrasound.

RESULTS

A shorter pulmonary AT and lower PATET ratio were found in the case group (34.8 ± 2.3, p < 0.001, 0.18 ± 0.02, p < 0.001, respectively). When comparing the groups that had an attack during pregnancy and had not, there were no significant differences in the pulmonary artery indices. We also demonstrated a moderate correlation between maternal disease years and the PATET ratio (r = -0.562, p = 0.004).

CONCLUSION

This is the first study to evaluate the effect of RA and AS on fetal pulmonary indices. Maternal inflammation might affect pulmonary development and circulation. Fetal pulmonary Doppler indices can be used to obtain further information about neonatal respiratory morbidities in rheumatological disorders.

The Significance of Epidermal Growth Factor in Noninvasively Obtained Amniotic Fluid Predicting Respiratory Outcomes of Preterm Neonates

Preterm premature rupture of membranes (PPROM) interrupts normal lung development, resulting in neonatal respiratory morbidity. Although post-PPROM risks have been researched, only a few studies have investigated noninvasively obtained amniotic fluid (AF) to predict neonatal outcomes. In this study, we aimed to determine whether epidermal growth factor (EGF) in vaginally-collected AF is a significant predictor of neonatal respiratory outcomes after PPROM. We analyzed EGF in vaginally-obtained AF from 145 women with PPROM at 22−34 weeks of gestation. The following neonatal outcomes were included: respiratory distress syndrome, surfactant need, duration and type of respiratory support, and bronchopulmonary dysplasia. We found that EGF concentration was associated with gestational age, and its medians were lower in neonates with respiratory morbidities than unaffected ones. EGF concentrations gradually declined, the lowest being in the most clinically ill patients. EGF < 35 pg/mL significantly predicted the odds of severe respiratory outcomes. EGF in noninvasively collected AF may be a reliable predictor for respiratory outcomes of preterm neonates with PPROM before 34 weeks of gestation. The results of our study may have implications for further research both in noninvasive amniotic fluid analysis and the management of patients after PPROM.

Unique inflammatory profile is associated with higher SARS-CoV-2 acute respiratory distress syndrome (ARDS) mortality

The COVID19 pandemic has caused more than a million of deaths worldwide, primarily due to complications from COVID19-associated acute respiratory distress syndrome (ARDS). Controversy surrounds the circulating cytokine/chemokine profile of COVID19-associated ARDS, with some groups suggesting that it is similar to patients without COVID19 ARDS and others observing substantial differences. Moreover, although a hyperinflammatory phenotype associates with higher mortality in non-COVID19 ARDS, there is little information on the inflammatory landscape's association with mortality in patients with COVID19 ARDS. Even though the circulating leukocytes' transcriptomic signature has been associated with distinct phenotypes and outcomes in critical illness including ARDS, it is unclear whether the mortality-associated inflammatory mediators from patients with COVID19 are transcriptionally regulated in the leukocyte compartment. Here, we conducted a prospective cohort study of 41 mechanically ventilated patients with COVID19 infection using highly calibrated methods to define the levels of plasma cytokines/chemokines and their gene expressions in circulating leukocytes. Plasma IL1RA and IL8 were found positively associated with mortality, whereas RANTES and EGF negatively associated with that outcome. However, the leukocyte gene expression of these proteins had no statistically significant correlation with mortality. These data suggest a unique inflammatory signature associated with severe COVID19.

Targeted Disruption of Mouse Dip2B Leads to Abnormal Lung Development and Prenatal Lethality

Molecular and anatomical functions of mammalian Dip2 family members (Dip2A, Dip2B and Dip2C) during organogenesis are largely unknown. Here, we explored the indispensable role of Dip2B in mouse lung development. Using a LacZ reporter, we explored Dip2B expression during embryogenesis. This study shows that Dip2B expression is widely distributed in various neuronal, myocardial, endothelial, and epithelial cell types during embryogenesis. Target disruption of Dip2b leads to intrauterine growth restriction, defective lung formation and perinatal mortality. Dip2B is crucial for late lung maturation rather than early-branching morphogenesis. The morphological analysis shows that Dip2b loss leads to disrupted air sac formation, interstitium septation and increased cellularity. In BrdU incorporation assay, it is shown that Dip2b loss results in increased cell proliferation at the saccular stage of lung development. RNA-seq analysis reveals that 1431 genes are affected in Dip2b deficient lungs at E18.5 gestation age. Gene ontology analysis indicates cell cycle-related genes are upregulated and immune system related genes are downregulated. KEGG analysis identifies oxidative phosphorylation as the most overrepresented pathways along with the G2/M phase transition pathway. Loss of Dip2b de-represses the expression of alveolar type I and type II molecular markers. Altogether, the study demonstrates an important role of Dip2B in lung maturation and survival.

Choice of Differentiation Media Significantly Impacts Cell Lineage and Response to CFTR Modulators in Fully Differentiated Primary Cultures of Cystic Fibrosis Human Airway Epithelial Cells

In vitro cultures of primary human airway epithelial cells (hAECs) grown at air–liquid interface have become a valuable tool to study airway biology under normal and pathologic conditions, and for drug discovery in lung diseases such as cystic fibrosis (CF). An increasing number of different differentiation media, are now available, making comparison of data between studies difficult. Here, we investigated the impact of two common differentiation media on phenotypic, transcriptomic, and physiological features of CF and non-CF epithelia. Cellular architecture and density were strongly impacted by the choice of medium. RNA-sequencing revealed a shift in airway cell lineage; one medium promoting differentiation into club and goblet cells whilst the other enriched the growth of ionocytes and multiciliated cells. Pathway analysis identified differential expression of genes involved in ion and fluid transport. Physiological assays (intracellular/extracellular pH, Ussing chamber) specifically showed that ATP12A and CFTR function were altered, impacting pH and transepithelial ion transport in CF hAECs. Importantly, the two media differentially affected functional responses to CFTR modulators. We argue that the effect of growth conditions should be appropriately determined depending on the scientific question and that our study can act as a guide for choosing the optimal growth medium for specific applications.

Pulmonary Consequences of Prenatal Inflammatory Exposures: Clinical Perspective and Review of Basic Immunological Mechanisms

Chorioamnionitis, a potentially serious inflammatory complication of pregnancy, is associated with the development of an inflammatory milieu within the amniotic fluid surrounding the developing fetus. When chorioamnionitis occurs, the fetal lung finds itself in the unique position of being constantly exposed to the consequent inflammatory meditators and/or microbial products found in the amniotic fluid. This exposure results in significant changes to the fetal lung, such as increased leukocyte infiltration, altered cytokine, and surfactant production, and diminished alveolarization. These alterations can have potentially lasting impacts on lung development and function. However, studies to date have only begun to elucidate the association between such inflammatory exposures and lifelong consequences such as lung dysfunction. In this review, we discuss the pathogenesis of and fetal immune response to chorioamnionitis, detail the consequences of chorioamnionitis exposure on the developing fetal lung, highlighting the various animal models that have contributed to our current understanding and discuss the importance of fetal exposures in regard to the development of chronic respiratory disease. Finally, we focus on the clinical, basic, and therapeutic challenges in fetal inflammatory injury to the lung, and propose next steps and future directions to improve our therapeutic understanding of this important perinatal stress.

Epidermal growth factor attenuates lingual papillae lesions in a rat model of sialoadenectomy

Salivary epidermal growth factor (EGF) plays an important role in the maintenance of the oral and gastro-esophageal mucosa. Sialoadenectomy delays healing of oral wounds and affects lingual papillae. In this work, we aimed to determine the effect of EGF deficiency induced by sialoadenectomy and evaluate the effect of exogenous EGF administration on the lingual papillae and taste buds in rats. Thirty male adult Wistar albino rats were equally divided into 3 groups; sham-operated control group, sialoadenectomy group and group of sialoadenectomy + EGF. EGF was given 8 weeks after sialoadenectomy in a dose of 1 μg /ml/day in drinking water for 2 weeks. The anterior two-thirds of the tongue was dissected and cut longitudinally into two halves; one half for light microscope and the other for electron microscope examinations. Saliva and blood were collected to determine salivary and plasma EGF. Our results revealed that sialoadenectomy significantly reduced plasma and saliva levels of EGF which resulted in severe disruption of the architecture of lingual papillae. These changes were effectively improved by the exogenous EGF administration. In conclusion, EGF supplementation reversed the effects of sialoadenectomy and restored almost normal architecture of lingual papillae and taste buds.

Recent advances in our understanding of the mechanisms of lung alveolarization and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common cause of morbidity and mortality in preterm infants. A key histopathological feature of BPD is stunted late lung development, where the process of alveolarization-the generation of alveolar gas exchange units-is impeded, through mechanisms that remain largely unclear. As such, there is interest in the clarification both of the pathomechanisms at play in affected lungs, and the mechanisms of de novo alveoli generation in healthy, developing lungs. A better understanding of normal and pathological alveolarization might reveal opportunities for improved medical management of affected infants. Furthermore, disturbances to the alveolar architecture are a key histopathological feature of several adult chronic lung diseases, including emphysema and fibrosis, and it is envisaged that knowledge about the mechanisms of alveologenesis might facilitate regeneration of healthy lung parenchyma in affected patients. To this end, recent efforts have interrogated clinical data, developed new-and refined existing-in vivo and in vitro models of BPD, have applied new microscopic and radiographic approaches, and have developed advanced cell-culture approaches, including organoid generation. Advances have also been made in the development of other methodologies, including single-cell analysis, metabolomics, lipidomics, and proteomics, as well as the generation and use of complex mouse genetics tools. The objective of this review is to present advances made in our understanding of the mechanisms of lung alveolarization and BPD over the period 1 January 2017-30 June 2019, a period that spans the 50th anniversary of the original clinical description of BPD in preterm infants.

Reversal of Surfactant Protein B Deficiency in Patient Specific Human Induced Pluripotent Stem Cell Derived Lung Organoids by Gene Therapy

Surfactant protein B (SFTPB) deficiency is a fatal disease affecting newborn infants. Surfactant is produced by alveolar type II cells which can be differentiated in vitro from patient specific induced pluripotent stem cell (iPSC)-derived lung organoids. Here we show the differentiation of patient specific iPSCs derived from a patient with SFTPB deficiency into lung organoids with mesenchymal and epithelial cell populations from both the proximal and distal portions of the human lung. We alter the deficiency by infecting the SFTPB deficient iPSCs with a lentivirus carrying the wild type SFTPB gene. After differentiating the mutant and corrected cells into lung organoids, we show expression of SFTPB mRNA during endodermal and organoid differentiation but the protein product only after organoid differentiation. We also show the presence of normal lamellar bodies and the secretion of surfactant into the cell culture medium in the organoids of lentiviral infected cells. These findings suggest that a lethal lung disease can be targeted and corrected in a human lung organoid model in vitro.

Insights into Early Recovery from Influenza Pneumonia by Spatial and Temporal Quantification of Putative Lung Regenerating Cells and by Lung Proteomics

During influenza pneumonia, the alveolar epithelial cells of the lungs are targeted by the influenza virus. The distal airway stem cells (DASCs) and proliferating alveolar type II (AT2) cells are reported to be putative lung repair cells. However, their relative spatial and temporal distribution is still unknown during influenza-induced acute lung injury. Here, we investigated the distribution of these cells, and concurrently performed global proteomic analysis of the infected lungs to elucidate and link the cellular and molecular events during influenza pneumonia recovery. BALB/c mice were infected with a sub-lethal dose of influenza H1N1 virus. From 5 to 25 days post-infection (dpi), mouse lungs were subjected to histopathologic and immunofluorescence analysis to probe for global distribution of lung repair cells (using P63 and KRT5 markers for DASCs; SPC and PCNA markers for AT2 cells). At 7 and 15 dpi, infected mouse lungs were also subjected to protein mass spectrometry for relative protein quantification. DASCs appeared only in the damaged area of the lung from 7 dpi onwards, reaching a peak at 21 dpi, and persisted until 25 dpi. However, no differentiation of DASCs to AT2 cells was observed by 25 dpi. In contrast, AT2 cells began proliferating from 7 dpi to replenish their population, especially within the boundary area between damaged and undamaged areas of the infected lungs. Mass spectrometry and gene ontology analysis revealed prominent innate immune responses at 7 dpi, which shifted towards adaptive immune responses by 15 dpi. Hence, proliferating AT2 cells but not DASCs contribute to AT2 cell regeneration following transition from innate to adaptive immune responses during the early phase of recovery from influenza pneumonia up to 25 dpi.

Targeted high-throughput sequencing of candidate genes for chronic obstructive pulmonary disease

Background

Reduced lung function in patients with chronic obstructive pulmonary disease (COPD) is likely due to both environmental and genetic factors. We report here a targeted high-throughput DNA sequencing approach to identify new and previously known genetic variants in a set of candidate genes for COPD.

Methods

Exons in 22 genes implicated in lung development as well as 61 genes and 10 genomic regions previously associated with COPD were sequenced using individual DNA samples from 68 cases with moderate or severe COPD and 66 controls matched for age, gender and smoking. Cases and controls were selected from the Obstructive Lung Disease in Northern Sweden (OLIN) studies.

Results

In total, 37 genetic variants showed association with COPD (p < 0.05, uncorrected). Several variants previously discovered to be associated with COPD from genetic genome-wide analysis studies were replicated using our sample. Two high-risk variants were followed-up for functional characterization in a large eQTL mapping study of 1,111 human lung specimens. The C allele of a synonymous variant, rs8040868, predicting a p.(S45=) in the gene for cholinergic receptor nicotinic alpha 3 (CHRNA3) was associated with COPD (p = 8.8 x 10⁻³). This association remained (p = 0.003 and OR = 1.4, 95 % CI 1.1-1.7) when analysing all available cases and controls in OLIN (n = 1,534). The rs8040868 variant is in linkage disequilibrium with rs16969968 previously associated with COPD and altered expression of the CHRNA5 gene. A follow-up analysis for detection of expression quantitative trait loci revealed that rs8040868-C was found to be significantly associated with a decreased expression of the nearby gene cholinergic receptor, nicotinic, alpha 5 (CHRNA5) in lung tissue.

Conclusion

Our data replicate previous result suggesting CHRNA5 as a candidate gene for COPD and rs8040868 as a risk variant for the development of COPD in the Swedish population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0309-y) contains supplementary material, which is available to authorized users.

SMAD Signaling in the Airways of Healthy Rhesus Macaques versus Rhesus Macaques with Asthma Highlights a Relationship Between Inflammation and Bone Morphogenetic Proteins

Bone morphogenetic protein (BMP) signaling is important for correct lung morphogenesis, and there is evidence of BMP signaling reactivation in lung diseases. However, little is known about BMP signaling patterns in healthy airway homeostasis and inflammatory airway disease and during epithelial repair. In this study, a rhesus macaque (Macaca mulatta) model of allergic airway disease was used to investigate BMP signaling throughout the airways in health, disease, and regeneration. Stereologic quantification of immunofluorescent images was used to determine the expression of BMP receptor (BMPR) Ia and phosphorylated SMAD (pSMAD) 1/5/8 in the airway epithelium. A pSMAD 1/5/8 expression gradient was found along the airways of healthy juvenile rhesus macaques (n = 3, P < 0.005). Membrane-localized BMPRIa expression was also present in the epithelium of the healthy animals. After exposure to house dust mite allergen and ozone, significant down-regulation of nuclear pSMAD 1/5/8 occurs in the epithelium. When the animals were provided with a recovery period in filtered air, proliferating cell nuclear antigen, pSMAD 1/5/8, and membrane-localized BMPRIa expression were significantly increased in the epithelium of conducting airways (P < 0.005). Furthermore, in the asthmatic airways, altered BMPRIa localization was evident. Because of the elevated eosinophil presence in these airways, we investigated the effect of eosinophil-derived proteins on BMPRIa trafficking in epithelial cells. Eosinophil-derived proteins (eosinophil-derived neurotoxin, eosinophil peroxidase, and major basic protein) induced transient nuclear translocation of membrane-bound BMPRIa. This work mapping SMAD signaling in the airways of nonhuman primates highlights a potential mechanistic relationship between inflammatory mediators and BMP signaling and provides evidence that basal expression of the BMP signaling pathway may be important for maintaining healthy airways.

Temporal dynamics of the developing lung transcriptome in three common inbred strains of laboratory mice reveals multiple stages of postnatal alveolar development

To characterize temporal patterns of transcriptional activity during normal lung development, we generated genome wide gene expression data for 26 pre- and post-natal time points in three common inbred strains of laboratory mice (C57BL/6J, A/J, and C3H/HeJ). Using Principal Component Analysis and least squares regression modeling, we identified both strain-independent and strain-dependent patterns of gene expression. The 4,683 genes contributing to the strain-independent expression patterns were used to define a murine Developing Lung Characteristic Subtranscriptome (mDLCS). Regression modeling of the Principal Components supported the four canonical stages of mammalian embryonic lung development (embryonic, pseudoglandular, canalicular, saccular) defined previously by morphology and histology. For postnatal alveolar development, the regression model was consistent with four stages of alveolarization characterized by episodic transcriptional activity of genes related to pulmonary vascularization. Genes expressed in a strain-dependent manner were enriched for annotations related to neurogenesis, extracellular matrix organization, and Wnt signaling. Finally, a comparison of mouse and human transcriptomics from pre-natal stages of lung development revealed conservation of pathways associated with cell cycle, axon guidance, immune function, and metabolism as well as organism-specific expression of genes associated with extracellular matrix organization and protein modification. The mouse lung development transcriptome data generated for this study serves as a unique reference set to identify genes and pathways essential for normal mammalian lung development and for investigations into the developmental origins of respiratory disease and cancer. The gene expression data are available from the Gene Expression Omnibus (GEO) archive (GSE74243). Temporal expression patterns of mouse genes can be investigated using a study specific web resource (http://lungdevelopment.jax.org).

A Pathophysiologic Approach to Biomarkers in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is an acute-onset hypoxic condition with radiographic bilateral lung infiltration. It is characterized by an acute exudative phase combining diffuse alveolar damage and lung edema followed by a later fibroproliferative phase. Despite an improved understanding of ARDS pathobiology, our ability to predict the development of ARDS and risk-stratify patients with the disease remains limited. Biomarkers may help to identify patients at the highest risk of developing ARDS, assess response to therapy, predict outcome, and optimize enrollment in clinical trials. After a short description of ARDS pathobiology, here, we review the scientific evidence that supports the value of various ARDS biomarkers with regard to their major biological roles in ARDS-associated lung injury and/or repair. Ongoing research aims at identifying and characterizing novel biomarkers, in order to highlight relevant mechanistic explorations of lung injury and repair, and to ultimately develop innovative therapeutic approaches for ARDS patients. This review will focus on the pathophysiologic, diagnostic, and therapeutic implications of biomarkers in ARDS and on their utility to ultimately improve patient care.

Lung growth factors in the amniotic fluid of normal pregnancies and with congenital diaphragmatic hernia

AIM

Respiratory failure secondary to pulmonary hypoplasia is the main cause of death in congenital diaphragmatic hernia (CDH). Lung growth is regulated by growth factors (GFs), whose imbalances are reported in pathological conditions. We measured amniotic fluid levels of GFs, regulating lung development, in pregnancies with CDH and compared them with normal gestations.

METHODS

Amniotic fluid was collected at amniocentesis and delivery from 4 women carrying fetuses with CDH and 12 with normal pregnancy. GFs were isolated and quantified. Same GFs were measured in lung biopsies collected during autopsy of three newborns dead of CDH.

RESULTS

Impairment expression of lung GFs in the amniotic fluid of CDH pregnancies in comparison with normal was found. Fibroblast growth factor 10 (FGF10), fibroblast growth factor 7, vascular endothelial growth factor and transforming growth factor β (TGFβ) were decreased at amniocentesis, while platelet-derived growth factor (PDGF) increased. While FGF10 and PDGF tended to normalize at delivery, epidermal growth factor increased and TGFβ was still decreased. Same GFs were similarly expressed in both lungs of babies dead of CDH.

CONCLUSION

Anomalies in lung GFs expression of embryos and fetuses with CDH can be detected by measuring their levels in the amniotic fluid during pregnancy. Further investigation would help to correlate prenatal expression of GFs and clinical outcome of babies with CDH after birth.

Intersectin-1s: an important regulator of cellular and molecular pathways in lung injury

Abstract Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe syndromes resulting from the diffuse damage of the pulmonary parenchyma. ALI and ARDS are induced by a plethora of local or systemic insults, leading to the activation of multiple pathways responsible for injury, resolution, and repair or scarring of the lungs. Despite the large efforts aimed at exploring the roles of different pathways in humans and animal models and the great strides made in understanding the pathogenesis of ALI/ARDS, the only viable treatment options are still dependent on ventilator and cardiovascular support. Investigation of the pathophysiological mechanisms responsible for initiation and resolution or advancement toward lung scarring in ALI/ARDS animal models led to a better understanding of the disease's complexity and helped in elucidating the links between ALI and systemic multiorgan failure. Although animal models of ALI/ARDS have pointed out a variety of new ideas for study, there are still limited data regarding the initiating factors, the critical steps in the progression of the disease, and the central mechanisms dictating its resolution or progression to lung scarring. Recent studies link deficiency of intersectin-1s (ITSN-1s), a prosurvival protein of lung endothelial cells, to endothelial barrier dysfunction and pulmonary edema as well as to the repair/recovery from ALI. This review discusses the effects of ITSN-1s deficiency on pulmonary endothelium and its significance in the pathology of ALI/ARDS.

Therapeutic potential of growth factors in pulmonary emphysematous condition

Pulmonary emphysema is a major manifestation of chronic obstructive pulmonary disease (COPD), which is characterized by progressive destruction of alveolar parenchyma with persistent inflammation of the small airways. Such destruction in the distal respiratory tract is irreversible and irreparable. All-trans-retinoic acid was suggested as a novel therapy for regeneration of lost alveoli in emphysema. However, profound discrepancies were evident between studies. At present, no effective therapeutic options are available that allow for the regeneration of lost alveoli in emphysematous human lungs. Recently, some reports on rodent's models have suggested the beneficial effects of various growth factors toward alveolar maintenance and repair processes.

Comparative molecular developmental aspects of the mammalian- and the avian lungs, and the insectan tracheal system by branching morphogenesis: recent advances and future directions

Gas exchangers fundamentally form by branching morphogenesis (BM), a mechanistically profoundly complex process which derives from coherent expression and regulation of multiple genes that direct cell-to-cell interactions, differentiation, and movements by signaling of various molecular morphogenetic cues at specific times and particular places in the developing organ. Coordinated expression of growth-instructing factors determines sizes and sites where bifurcation occurs, by how much a part elongates before it divides, and the angle at which branching occurs. BM is essentially induced by dualities of factors where through feedback- or feed forward loops agonists/antagonists are activated or repressed. The intricate transactions between the development orchestrating molecular factors determine the ultimate phenotype. From the primeval time when the transformation of unicellular organisms to multicellular ones occurred by systematic accretion of cells, BM has been perpetually conserved. Canonical signalling, transcriptional pathways, and other instructive molecular factors are commonly employed within and across species, tissues, and stages of development. While much still remain to be elucidated and some of what has been reported corroborated and reconciled with rest of existing data, notable progress has in recent times been made in understanding the mechanism of BM. By identifying and characterizing the morphogenetic drivers, and markers and their regulatory dynamics, the elemental underpinnings of BM have been more precisely explained. Broadening these insights will allow more effective diagnostic and therapeutic interventions of developmental abnormalities and pathologies in pre- and postnatal lungs. Conservation of the molecular factors which are involved in the development of the lung (and other branched organs) is a classic example of nature's astuteness in economically utilizing finite resources. Once purposefully formed, well-tested and tried ways and means are adopted, preserved, and widely used to engineer the most optimal phenotypes. The material and time costs of developing utterly new instruments and routines with every drastic biological change (e.g. adaptation and speciation) are circumvented. This should assure the best possible structures and therefore functions, ensuring survival and evolutionary success.

Modulation of gap junction channels and hemichannels by growth factors

Gap junction hemichannels and cell-cell channels have roles in coordinating numerous cellular processes, due to their permeability to extra and intracellular signaling molecules. Another mechanism of cellular coordination is provided by a vast array of growth factors that interact with relatively selective cell membrane receptors. These receptors can affect cellular transduction pathways, including alteration of intracellular concentration of free Ca(2+) and free radicals and activation of protein kinases or phosphatases. Connexin and pannexin based channels constitute recently described targets of growth factor signal transduction pathways, but little is known regarding the effects of growth factor signaling on pannexin based channels. The effects of growth factors on these two channel types seem to depend on the cell type, cell stage and connexin and pannexin isoform expressed. The functional state of hemichannels and gap junction channels are affected in opposite directions by FGF-1 via protein kinase-dependent mechanisms. These changes are largely explained by channels insertion in or withdrawal from the cell membrane, but changes in open probability might also occur due to changes in phosphorylation and redox state of channel subunits. The functional consequence of variation in cell-cell communication via these membrane channels is implicated in disease as well as normal cellular responses.

HIF-1α signaling by airway epithelial cell K-α1-tubulin: role in fibrosis and chronic rejection of human lung allografts

Long term survival of the human lung allografts are hindered by chronic rejection, manifested clinically as bronchiolitis obliterans syndrome (BOS). We previously demonstrated significant correlation between the development of antibodies (Abs) to K-α1-tubulin (Kα1T) and BOS. In this study, we investigated the molecular basis for fibrinogenesis mediated by ligation of Kα1T expressed on airway epithelial cells by its specific Abs. Using RT-PCR we demonstrate that normal human bronchial epithelial (NHBE) cells upon ligation of Kα1T with specific Abs caused upregulation of pro-fibrotic growth factors. Western blot analysis of NHBE incubated with Kα1T Abs increased hypoxia inducible factor (HIF-1α). Kα1T Ab-mediated growth factor expression is dependent on HIF-1α as inhibition of HIF-1α returned fibrotic growth factor expression to basal levels. In conclusion, we propose that HIF-1α -mediated upregulation of fibrogenic growth factors induced by ligation of Kα1T Abs is critical for development of fibrosis leading to chronic rejection of lung allograft.

Biomarkers in acute lung injury: insights into the pathogenesis of acute lung injury

Studies of potential biomarkers of acute lung injury (ALI) have provided information relating to the pathophysiology of the mechanisms of lung injury and repair. The utility of biomarkers remains solely among research tools to investigate lung injury and repair mechanisms. Because of lack of sensitivity and specificity, they cannot be used in decision making in patients with ALI or acute respiratory distress syndrome. The authors reviewed known biomarkers in context of their major biologic activity. The continued interest in identifying and studying biomarkers is relevant, as it provides information regarding the mechanisms involved in lung injury and repair and how this may be helpful in identifying and designing future therapeutic targets and strategies and possibly identifying a sensitive and specific biomarker.

Light-dark oscillations in the lung transcriptome: implications for lung homeostasis, repair, metabolism, disease, and drug action

Diurnal-nocturnal, or circadian-like, rhythms are 24-h variations in biological processes, evolved for the efficient functioning of living organisms. Such oscillations and their regulation in many peripheral tissues are still unclear. In this study, we used Affymetrix gene chips in a rich time-series experiment involving 54 animals killed at 18 time points within the 24-h cycle to examine light-dark cycle patterns of gene expression in rat lungs. Data mining identified 646 genes (represented by 1,006 probe sets) showing robust oscillations in expression in lung that were parsed into 8 distinct temporal clusters. Surprisingly, more than two-thirds of the probe sets showing cyclic expression peaked during the animal's light/inactive period. Six core clock genes and nine clock-related genes showed rhythmic oscillations in their expression in lung. Many of the genes that peaked during the inactive period included genes related to extracellular matrix, cytoskeleton, and protein processing and trafficking, which appear to be mainly involved in the repair and remodeling of the organ. Genes coding for growth factor ligands and their receptors, which play important roles in maintaining normal lung function, also showed rhythmic expression. In addition, genes involved in the metabolism and transport of endogenous compounds, xenobiotics, and therapeutic drugs, along with genes that are biomarkers or potential therapeutic targets for many lung diseases, also exhibited 24-h cyclic oscillations, suggesting an important role for such rhythms in regulating various aspects of the physiology and pathophysiology of lung.

Effects of fibroblast growth factors on the differentiation of the pulmonary progenitors from murine embryonic stem cells

The fibroblast growth factors (FGFs) play an important role in the development of embryonic lung. In this study, we investigated the effects of mainly FGF 1, 2, and 10 at concentrations selected on the basis of data obtained from previous in vitro culture on the derivation of the pulmonary progenitors from murine embryonic stem cells cultured on gelatin or Matrigel-coated plates. For cells cultured on a gelatin-coated plate, high concentrations of FGF1 were found to enhance the expression of mRNAs for SPC and CC10, markers of distal airway epithelium, while high levels of FGF2 decreased the expression of RNAs for not only SPC, CC10 but also for the additional markers SPD and aquaporin 5. FGF10 at all tested concentrations was found to have no effect on the differentiation of pneumocytes when ESCs were grown on gelatin-coated plates. However, when differentiation was performed on Matrigel-coated plates, the addition of 60 ng/ml FGF10 enhanced the expression of pneumocyte markers, suggesting a synergic effect of FGF10 and extracellular matrix. In conclusion, growth factors were proven to be effective in the differentiation of pulmonary progenitors from mESCs. The need of signals from extracellular matrix proteins depends on the growth factors supplemented.

Novel therapeutic strategies for acute lung injury induced by lung damaging agents: the potential role of growth factors as treatment options

The increasing threat from terrorism has brought attention to the possible use of toxic industrial compounds (TICs) and other lung-damaging agents as weapons against civilian populations. The way in which these agents could be used favours the development of generic countermeasures. Improved medical countermeasures would increase survivability and improve the quality of recovery of lung damaged casualties. It is evident that there is a dearth of therapeutic regimes available to treat those forms of lung damage that currently require intensive care management. It is quite possible that mass casualties from a terrorist incident or major industrial accident involving the release of large quantities of inhaled TICs would place a severe burden on already scarce intensive care facilities. The development of effective pharmacological approaches to assist the recovery of casualties suffering from acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) may improve the prognosis of such patients (which is currently poor) and would ideally be used as a means of preventing subjects from developing the pulmonary oedema characteristic of ALI/ARDS. Many promising candidate pharmacological treatments have been evaluated for the treatment of ALI/ARDS, but their clinical value is often debatable. Thus, despite improvements in ventilation strategies, pharmacological intervention for ALI/ARDS remains problematical. A new approach is clearly required for the treatment of patients with severely compromised lungs. Whilst the pathology of ALI/ARDS associated with exposure to a variety of agents is complex, numerous experimental studies suggest that generic therapeutic intervention directed at approaches that aim to upregulate repair of the damaged alveolar blood/air barrier of the lung may be of value, particularly with respect to chemical-induced injury. To this end, keratinocyte growth factor (KGF), epithelial growth factor (EGF) and basic fibroblast growth factor (bFGF) are emerging as the most important candidates. Hepatocyte growth factor (HGF) does not have epithelial specificity for lung tissue. However, the enhanced effects of combinations of growth factors, such as the synergistic effect of HGF upon vascular endothelial growth factor (VEGF)-mediated endothelial cell activity, and the combined effect of HGF and KGF in tissue repair should be investigated, particularly as the latter pair of growth factors are frequently implicated in processes associated with the repair of lung damage. Synergistic interactions also occur between trefoil factor family (TFF) peptides and growth factors such as EGF. TFF peptides are most likely to be of value as a short term therapeutic intervention strategy in stimulating epithelial spreading activities which allow damaged mucosal surfaces to be rapidly covered by epithelial cells.

Neurotrophic and neuroimmune responses to early-life Pseudomonas aeruginosa infection in rat lungs

Early-life respiratory infection with Pseudomonas aeruginosa is common in children with cystic fibrosis or immune deficits. Although many of its clinical manifestations involve neural reflexes, little information is available on the peripheral nervous system of infected airways. This study sought to determine whether early-life infection triggers a neurogenic-mediated immunoinflammatory response, the mechanisms of this response, and its relationship with other immunoinflammatory pathways. Weanling and adult rats were inoculated with suspensions containing P. aeruginosa (PAO1) coated on alginate microspheres suspended in Tris-CaCl(2) buffer. Five days after infection, rats were injected with capsaicin to stimulate nociceptive nerves in the airway mucosa, and microvascular permeability was measured using Evans blue as a tracer. PAO1 increased neurogenic inflammation in the extra- and intrapulmonary compartments of weanlings but not in adults. The mechanism involves selective overexpression of NGF, which is critical for the local increase in microvascular permeability and for the infiltration of polymorphonuclear leukocytes into infected lung parenchyma. These effects are mediated in part by induction of downstream inflammatory cytokines and chemokines, especially IL-1beta, IL-18, and leptin. Our data suggest that neurogenic-mediated immunoinflammatory mechanisms play important roles in airway inflammation and hyperreactivity associated with P. aeruginosa when infection occurs early in life.

Effect of covalent antithrombin-heparin complex on developmental mechanisms in the lung

We have developed a potent antithrombin (AT)-heparin conjugate (ATH) that is retained in the lung to prevent pulmonary thrombosis associated with respiratory distress in premature newborns. During continuing maturation, pulmonary angiogenesis in premature infants would be a crucial process in lung development. A naturally occurring latent form of antithrombin (L-AT) has antiangiogenic effects on lung vascularization. However, impact of latent ATH (L-ATH) on developing lung vascularization is unknown. Thus, effects of L-AT and L-ATH on fetal murine lung development were compared. Lung buds from embryonic day 11.5 (E11.5) Tie2-LacZ mouse embryos were incubated in DMEM plus FBS supplemented with PBS, AT, L-AT, heparin, ATH, or L-ATH. Vasculature of cultured explants was quantified by X-galactosidase staining. RNA was analyzed with murine gene probes for angiopoietin (Ang)-1, Ang-2, fibroblast growth factor 2 (FGF2), platelet endothelial cell adhesion molecule (PECAM), and vascular endothelial growth factor (VEGF). FGF2-supplemented medium was used to test contribution to effects of L-AT and L-ATH on angiogenesis. Epithelial branching morphogenesis was inhibited by L-AT (P = 0.003) and heparin (P < 0.001). L-AT and heparin decreased relative vascular area compared with PBS, ATH, and L-ATH. Expressions of all genes studied were downregulated by L-AT. However, L-AT and L-ATH inhibited branching morphogenesis and vasculature with added FGF2. These findings indicate that covalent linkage of AT to heparin negates disruptive effects of these moieties on lung morphology, vascularization, and growth factor gene expression. ATH may have enhanced safety as an anticoagulant during vascular development.

Sex-specific association of epidermal growth factor gene polymorphisms with acute respiratory distress syndrome

Epidermal growth factor (EGF) is involved in alveolar epithelial repair, lung fluid clearance and inflammation, and is regulated by sex hormones. An unmatched, nested case-control study was conducted to evaluate the associations of EGF variants with acute respiratory distress syndrome (ARDS) and the role of sex on the associations between EGF variants and ARDS. Patients with ARDS risk factors upon intensive care unit admission were enrolled. Cases were 416 Caucasians who developed ARDS and controls were 1,052 Caucasians who did not develop ARDS. Cases were followed for clinical outcomes and 60-day mortality. One functional single nucleotide polymorphism (SNP), rs4444903, and six haplotype-tagging SNPs spanning the entire EGF gene were genotyped. No individual SNP or haplotype was associated with ARDS risk or outcomes in all subjects. Sex-stratified analyses showed opposite effects of EGF variants on ARDS in males versus in females. SNPs rs4444903, rs2298991, rs7692976 and rs4698803, and haplotypes GGCGTC and ATCAAG were associated with ARDS risk in males. No associations were observed in females. Interaction analysis showed that rs4444903, rs2298991, rs7692976 and rs6533485 significantly interacted with sex for ARDS risk. The present study suggests that associations of epidermal growth factor gene variants with acute respiratory distress syndrome risk are modified by sex. The current findings should be replicated in other populations.

Developmental cell/molecular biologic approach to the etiology and treatment of bronchopulmonary dysplasia

We have taken a basic biologic approach to elucidate the pathophysiology of bronchopulmonary dysplasia (BPD), the chronic lung disease of prematurity, based on cell/molecular mechanisms of physiologic lung development. Stretch coordinates parathyroid hormone-related protein (PTHrP) signaling between the alveolar type II cell and the mesoderm to coordinately up-regulate key genes for the homeostatic fibroblast phenotype- including peroxisome proliferator activated receptor gamma (PPARgamma), adipocyte differentiation related protein (ADRP), and leptin- and the retrograde stimulation of type II cell surfactant synthesis by leptin. Each of these paracrine interactions requires cell-specific receptors on adjacent cells derived from the mesoderm or endoderm, respectively, to serially up-regulate the signaling pathways between and within each cell-type. It is this functional compartmentation that is key to understanding how specific agonists and antagonists can predictably affect this mechanism of alveolar homeostasis. Using a wide variety of pathophysiologic insults associated with BPD- barotrauma, oxotrauma, and infection, we have found that there are type II cell and/or fibroblast cell/molecular effects generated by these insults, which can lead to the BPD phenotype. We have exploited these cell-specific mechanisms to effectively prevent and treat lung injuries using PPARgamma agonists to sustain this signaling pathway. It is critically important to judiciously select physiologically and developmentally relevant interventions when treating the preterm neonate.

Growth factors gene expression in the developing lung

AIM

This is the first systematic study using quantitative real-time PCR to analyze and compare the expression profiles for critical members of the epidermal growth factor (EGF), transforming growth factor beta (TGFbeta), and vascular endothelial growth factor (VEGF) families in developing rat lungs.

METHODS

mRNA expression was quantified at embryonic (E) day 15, 17, 19, 21, and postnatal age 1 day, 2 weeks, 12 weeks.

RESULTS

EGF and EGFR increased during gestation and development, then decreased in adulthood, whereas TGFalpha was highest at birth and remained unchanged afterwards. All TGFbeta isoforms increased slightly during pregnancy, reached highest expression during development, and returned to neonatal levels in adulthood. TGFbetaRI and TGFbetaRII patterns were similar to TGFbeta2 and TGFbeta1 respectively, whereas TGFbetaRIII expression was lowest at the postnatal time points. VEGF(164) and VEGF(120) showed a steady increase up to 2 weeks and declined at 12 weeks, whereas highest VEGF(188) expression occurred at 12 weeks. VEGF-A receptors expression paralleled the summation of all three isoforms, increasing steadily with age.

CONCLUSION

Expression of growth factors in the developing lung is characterized by highly regulated distinctive patterns that may be critical to understand the early origin and progression of pulmonary diseases in childhood as well as in adulthood. Quantitative real-time PCR analysis revealed several differences compared to previously reported expression patterns defined with older methodologies.

Deficiency in type 1 insulin-like growth factor receptor in mice protects against oxygen-induced lung injury

Background

Cellular responses to aging and oxidative stress are regulated by type 1 insulin-like growth factor receptor (IGF-1R). Oxidant injury, which is implicated in the pathophysiology of a number of respiratory diseases, acutely upregulates IGF-1R expression in the lung. This led us to suspect that reduction of IGF-1R levels in lung tissue could prevent deleterious effects of oxygen exposure.

Methods

Since IGF-1R null mutant mice die at birth from respiratory failure, we generated compound heterozygous mice harboring a hypomorphic (Igf-1r^neo) and a knockout (Igf-1r^-) receptor allele. These IGF-1R^neo/- mice, strongly deficient in IGF-1R, were subjected to hyperoxia and analyzed for survival time, ventilatory control, pulmonary histopathology, morphometry, lung edema and vascular permeability.

Results

Strikingly, after 72 h of exposure to 90% O₂, IGF-1R^neo/- mice had a significantly better survival rate during recovery than IGF-1R^+/+ mice (77% versus 53%, P < 0.05). The pulmonary injury was consistently, and significantly, milder in IGF-1R^neo/- mice which developed conspicuously less edema and vascular extravasation than controls. Also, hyperoxia-induced abnormal pattern of breathing which precipitated respiratory failure was elicited less frequently in the IGF-1R^neo/- mice.

Conclusion

Together, these data demonstrate that a decrease in IGF-1R signaling in mice protects against oxidant-induced lung injury.

Time course of serum cytokines in patients receiving proton or combined photon/proton beam radiation for resectable but medically inoperable non-small-cell lung cancer

PURPOSE

We prospectively measured the levels of basic fibroblast growth factor (bFGF), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, IL-10, and procollagen III peptide (P III P) in serum from non-small-cell lung cancer patients treated with photons combined with protons or protons alone. These factors were quantified because they may be extremely important in the development of side effects, and the treated volume integral dose may be crucial in inducing them.

METHODS

Of the 12 participating patients, 6 with squamous cell carcinoma (SCC) and 3 with adenocarcinoma received combined photon/proton beam radiation, whereas 2 with SCC and 1 with large-cell carcinoma (LCC) received only proton radiation. Mean age was 73.6 years. There were 4 male and 8 female patients with a mean smoking history of 87.0 packyears. Nine patients had Stage I, 2 had Stage II, and 1 had stage IIIA lung cancer. Serum samples were obtained at baseline and on Days 15, 30, 45, 60, 90, 120, 150, 180, and 210 after initiation of radiation therapy. Injury scores for pneumonitis and fibrosis based on computed tomography (CT) scans were assigned.

RESULTS

The percentage of lung volume irradiated was significantly less for patients treated with protons alone compared with those receiving photon plus proton therapy (p < 0.001). Injury scores were also lower for proton only treatment (p = 0.039). When evaluated collectively, bFGF, TNF-alpha, and IL-6 concentrations were significantly higher in the photon/proton group (p < 0.05 or less); radiation regimen, but not time after treatment initiation, was a significant factor in their levels. P III P level was also higher in the photon/proton patients (p < 0.001) and both radiation regimen (p = 0.027) and time after treatment (p = 0.019) had an impact.

CONCLUSIONS

Although significant changes occurred in some of the measured cytokines and P III P, it was the difference in the volume integral dose that occurred when protons were used alone vs. mixed photon/proton therapy that correlated with the incidence of pneumonitis and/or fibrosis. However, it cannot be ruled out that differences in cytokine levels before radiotherapy initiation may have contributed to the outcome.

Sex and gender differences in lung development and their clinical significance

Factors that affect airway growth-as early in development as in utero-seem to cause physiologic effects that can be persistent. Reduced airway function early in life does not necessarily result in persistent symptoms, but it does increase the risk of reduced lung function and the development of persistent airflow limitation in adult life, both in men and women. Normal lung growth varies with age and sex and is affected by a number of risk factors, which we have described. The importance of the various risk factors may differ depending at what point during lung growth they come into play and whether they occur in men or in women.

MEKK2 regulates the coordinate activation of ERK5 and JNK in response to FGF-2 in fibroblasts

Mitogen-activated protein kinases (MAPKs) are regulated by MAPK kinases (MKKs), which are in turn regulated by MKK kinases (MKKKs). While a single MKKK can regulate several different MAPK family members, and several MKKKs can often activate the same MAPK, emerging evidence indicates a unique role for individual MKKKs in acting as signaling nodes to coordinately activate different subsets of MAPKs in response to specific cellular stimuli. Thus, while there is much apparent overlap in MAPK regulation by different MKKKs, each MKKK serves a specific purpose in regulation of unique cellular functions. The purpose of this study was to define the specific role of MEKK2, an MKKK, in MAPK regulation and cell function. MEKK2 coordinately activates the ERK5 and JNK pathways. Targeted disruption of MEKK2 expression causes loss of ERK5 and JNK activation in response to FGF-2 in mouse embryonic fibroblasts (MEFs). FGF-2 receptor signaling requires MEKK2 for induction of mRNA for c-Jun, Fra-1, and Fra-2, components of the AP-1 transcription complex. In FGF-2-stimulated MEKK2-/- fibroblasts, c-Jun phosphorylation is inhibited, consistent with a loss of JNK activation. Thus, MEKK2 regulates AP-1 activity at two levels, by regulating both expression of AP-1 components and c-Jun N-terminal phosphorylation. One function of the AP-1 transcription complex is to regulate cytokine gene expression. Expression of IL-1alpha, IL-1beta, IL-6, and TNFalpha is inhibited in MEKK2-/- fibroblasts. Bacterial lipopolysaccharide (LPS) and TNFalpha neither activate ERK5 nor require MEKK2 for JNK activation, demonstrating specificity of MEKK2 in FGF-2 receptor signaling and control of cytokine gene expression.

Oxygen-sensing mechanisms and the regulation of redox-responsive transcription factors in development and pathophysiology

How do organisms sense the amount of oxygen in the environment and respond appropriately when the level of oxygen decreases? Oxygen sensing and the molecular stratagems underlying the process have been the focus of an endless number of investigations trying to find an answer to the question: "What is the identity of the oxygen sensor?" Dynamic changes in pO2 constitute a potential signaling mechanism for the regulation of the expression and activation of reduction-oxidation (redox)-sensitive and oxygen-responsive transcription factors, apoptosis-signaling molecules and inflammatory cytokines. The transition from placental to lung-based respiration causes a relatively hyperoxic shift or oxidative stress, which the perinatal, developing lung experiences during birth. This variation in DeltapO2, in particular, differentially regulates the compartmentalization and functioning of the transcription factors hypoxia-inducible factor-1alpha (HIF-1alpha) and nuclear factor-kappaB (NF-kappaB). In addition, oxygen-evoked regulation of HIF-1alpha and NF-kappaB is closely coupled with the intracellular redox state, such that modulating redox equilibrium affects their responsiveness at the molecular level (expression/transactivation). The differential regulation of HIF-1alpha and NF-kappaB in vitro is paralleled by oxygen-sensitive and redox-dependent pathways governing the regulation of these factors during the transition from placental to lung-based respiration ex utero. The birth transition period in vivo and ex utero also regulates apoptosis signaling pathways in a redox-dependent manner, consistent with NF-kappaB being transcriptionally regulated in order to play an anti-apoptotic function. An association is established between oxidative stress conditions and the augmentation of an inflammatory state in pathophysiology, regulated by the oxygen- and redox-sensitive pleiotropic cytokines.