WSB1, a Hypoxia-Inducible E3 Ligase, Promotes Myofibroblast Accumulation and Attenuates Alveolar Epithelial Regeneration in Mouse Lung Fibrosis

Idiopathic pulmonary fibrosis is a progressive interstitial lung disease for which there is no curative therapy available. Repetitive alveolar epithelial injury repair, myofibroblast accumulation, and excessive collagen deposition are key pathologic features of idiopathic pulmonary fibrosis, eventually leading to cellular hypoxia and respiratory failure. The precise mechanism driving this complex maladaptive process remains inadequately understood. WD repeat and suppressor of cytokine signaling box containing 1 (WSB1) is an E3 ubiquitin ligase, the expression of which is associated strongly with hypoxia, and forms a positive feedback loop with hypoxia-inducible factor 1α (HIF-1α) under anoxic condition. This study explored the expression, cellular distribution, and function of WSB1 in bleomycin (BLM)-induced mouse lung injury and fibrosis. WSB1 expression was highly induced by BLM injury and correlated with the progression of lung fibrosis. Significantly, conditional deletion of Wsb1 in adult mice ameliorated BLM-induced pulmonary fibrosis. Phenotypically, Wsb1-deficient mice showed reduced lipofibroblast to myofibroblast transition, but enhanced alveolar type 2 proliferation and differentiation into alveolar type 1 after BLM injury. Proteomic analysis of mouse lung tissues identified caveolin 2 as a potential downstream target of WSB1, contributing to BLM-induced epithelial injury repair and fibrosis. These findings unravel a vital role for WSB1 induction in lung injury repair, thus highlighting it as a potential therapeutic target for pulmonary fibrosis.

Injury activated alveolar progenitors (IAAPs): the underdog of lung repair

Alveolar epithelial type II cells (AT2s) together with AT1s constitute the epithelial lining of lung alveoli. In contrast to the large flat AT1s, AT2s are cuboidal and smaller. In addition to surfactant production, AT2s also serve as prime alveolar progenitors in homeostasis and play an important role during regeneration/repair. Based on different lineage tracing strategies in mice and single-cell transcriptomic analysis, recent reports highlight the heterogeneous nature of AT2s. These studies present compelling evidence for the presence of stable or transitory AT2 subpopulations with distinct marker expression, signaling pathway activation and functional properties. Despite demonstrated progenitor potentials of AT2s in maintaining homeostasis, through self-renewal and differentiation to AT1s, the exact identity, full progenitor potential and regulation of these progenitor cells, especially in the context of human diseases remain unclear. We recently identified a novel subset of AT2 progenitors named "Injury-Activated Alveolar Progenitors" (IAAPs), which express low levels of Sftpc, Sftpb, Sftpa1, Fgfr2b and Etv5, but are highly enriched for the expression of the surface receptor programmed cell death-ligand 1 (Pd-l1). IAAPs are quiescent during lung homeostasis but activated upon injury with the potential to proliferate and differentiate into AT2s. Significantly, a similar population of PD-L1 positive cells expressing intermediate levels of SFTPC are found to be expanded in human IPF lungs. We summarize here the current understanding of this newly discovered AT2 progenitor subpopulation and also try to reconcile the relationship between different AT2 stem cell subpopulations regarding their progenitor potential, regulation, and relevance to disease pathogenesis and therapeutic interventions.

Percentage of intrathoracic stomach predicts operative and post-operative morbidity, persistent reflux and PPI requirement following laparoscopic hiatus hernia repair and fundoplication

PURPOSE

Large hiatus hernias are relatively common and can be associated with adverse symptoms and serious complications. Operative repair is indicated in this patient group for symptom management and the prevention of morbidity. This study aimed to identify predictors of poor outcomes following laparoscopic hiatus hernia repair and fundoplication (LHHRaF) to aid in counselling potential surgical candidates.

METHODOLOGY

A retrospective analysis was performed from a prospectively maintained, multicentre database of patients who underwent LHHRaF between 2014 and 2020. Revision procedures were excluded. Hernia size was defined as the intraoperative percentage of intrathoracic stomach, estimated by the surgeon to the nearest 10%. Predictors of outcomes were determined using a prespecified multivariate logistic regression model.

RESULTS

625 patients underwent LHHRaF between 2014 and 2020 with 443 patients included. Median age was 65 years, 62.9% were female and 42.7% of patients had ≥ 50% intrathoracic stomach. In a multivariate regression model, intrathoracic stomach percentage was predictive of operative complications (P = 0.014, OR 1.05), post-operative complications (P = 0.026, OR 1.01) and higher comprehensive complication index score (P = 0.023, OR 1.04). At 12 months it was predictive of failure to improve symptomatic reflux (P = 0.008, OR 1.02) and persistent PPI requirement (P = 0.047, OR 1.02). Operative duration and blood loss were predicted by BMI (P = 0.004 and < 0.001), Type III/IV hernias (P = 0.045 and P = 0.005) and intrathoracic stomach percentage (P = 0.009 and P < 0.001). Post-operative length of stay was predicted by age (P < 0.001) and emergency presentation (P = 0.003).

CONCLUSION

In a multivariate regression model, intrathoracic stomach percentage was predictive of operative and post-operative morbidity, PPI use, and failure to improve reflux symptoms at 12 months.

FGF10 ameliorates lipopolysaccharide-induced acute lung injury in mice via the BMP4-autophagy pathway

Introduction: Damage to alveolar epithelial cells caused by uncontrolled inflammation is considered to be the main pathophysiological change in acute lung injury. FGF10 plays an important role as a fibroblast growth factor in lung development and lung diseases, but its protective effect against acute lung injury is unclear. Therefore, this study aimed to investigate protective effect and mechanism of FGF10 on acute lung injury in mice. Methods: ALI was induced by intratracheal injection of LPS into 57BL/6J mice. Six hours later, lung bronchoalveolar lavage fluid (BALF) was acquired to analyse cells, protein and the determination of pro-inflammatory factor levels, and lung issues were collected for histologic examination and wet/dry (W/D) weight ratio analysis and blot analysis of protein expression. Results: We found that FGF10 can prevent the release of IL-6, TNF-α, and IL-1β, increase the expression of BMP4 and autophagy pathway, promote the regeneration of alveolar epithelial type Ⅱ cells, and improve acute lung injury. BMP4 gene knockdown decreased the protective effect of FGF10 on the lung tissue of mice. However, the activation of autophagy was reduced after BMP4 inhibition by Noggin. Additionally, the inhibition of autophagy by 3-MA also lowered the protective effect of FGF10 on alveolar epithelial cells induced by LPS. Conclusions: These data suggest that the protective effect of FGF10 is related to the activation of autophagy and regeneration of alveolar epithelial cells in an LPS-induced ALI model, and that the activation of autophagy may depend on the increase in BMP4 expression.

FGF1 alleviates LPS-induced acute lung injury via suppression of inflammation and oxidative stress

Background

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), are devastating clinical disorders with high mortality, and for which more effective therapies are urgently needed. FGF1, the prototype member of the FGF family, is shown to exert protective effects against injurious stimuli in multiple disease models. Here we aimed to evaluate whether FGF1 pretreatment is protective against LPS-induced ALI and elucidate the potential underlying mechanisms.

Methods

For drug-treated groups, C57B/6 mice received a single i.p. injection of FGF1 (1 mg/kg) 1 h before the LPS challenge or not. To induce the ALI model, the mice were treated by intratracheal instillation of LPS (5 mg/kg). Then, histopathological changes in lung tissues were assessed by hematoxylin and eosin staining and transmission electron microscopy. ELISA and qPCR assays were used to detect pro-inflammatory cytokine levels in BALF and lung tissues, respectively. The total number of inflammatory cells (neutrophils and macrophages) in BALF were counted using the Wright-Giemsa method. The expressions of reactive oxygen species (ROS) and malondialdehyde (MDA) were measured using their respective kits. Western blot and immunostaining were used to evaluate the expressions of antioxidants (Nrf-2, HO-1, SOD2, GPX4, and Catalase), as well as the inflammatory and/or apoptosis-related factors (TLR4, NF-κB, and Cleaved- caspase 3).

Results

FGF1 pretreatment significantly ameliorated the LPS-induced histopathological changes, reduced lung wet/dry ratios, ROS and MDA levels, total BALF protein, inflammatory cell infiltration, proinflammatory cytokine levels, and significantly increased the expression of antioxidant proteins (Nrf-2, HO-1, Catalase, and SOD2). In addition, FGF1 pretreatment significantly reduced the expression of TLR4 and cleaved- caspase 3, inhibited NF-κB activation, and reduced LPS-induced cell apoptosis.

Conclusions

Altogether, our results suggest that FGF1 pretreatment is protective against LPS-induced ALI through mediating anti-inflammatory and antioxidant effects, which may be attributed to the downregulation of TLR4 expression and inhibition of NF-κB activation, as well as promotion of antioxidant defenses. Therefore, FGF1 administration may prove beneficial in preventative strategies for ALI/ARDS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00502-8.

Severity of oEsophageal Anastomotic Leak in patients after oesophagectomy: the SEAL score

Background

Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score.

Methods

This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally.

Results

Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification.

Conclusion

The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy.

FGFR2b signalling restricts lineage-flexible alveolar progenitors during mouse lung development and converges in mature alveolar type 2 cells

The specification, characterization, and fate of alveolar type 1 and type 2 (AT1 and AT2) progenitors during embryonic lung development are poorly defined. Current models of distal epithelial lineage formation fail to capture the heterogeneity and dynamic contribution of progenitor pools present during early development. Furthermore, few studies explore the pathways involved in alveolar progenitor specification and fate. In this paper, we build upon our previously published work on the regulation of airway epithelial progenitors by fibroblast growth factor receptor 2b (FGFR2b) signalling during early (E12.5) and mid (E14.5) pseudoglandular stage lung development. Our results suggest that a significant proportion of AT2 and AT1 progenitors are lineage-flexible during late pseudoglandular stage development, and that lineage commitment is regulated in part by FGFR2b signalling. We have characterized a set of direct FGFR2b targets at E16.5 which are likely involved in alveolar lineage formation. These signature genes converge on a subpopulation of AT2 cells later in development and are downregulated in AT2 cells transitioning to the AT1 lineage during repair after injury in adults. Our findings highlight the extensive heterogeneity of pneumocytes by elucidating the role of FGFR2b signalling in these cells during early airway epithelial lineage formation, as well as during repair after injury.

Validation of a Novel Fgf10 Cre-ERT2 Knock-in Mouse Line Targeting FGF10Pos Cells Postnatally

Fgf10 is a key gene during development, homeostasis and repair after injury. We previously reported a knock-in Fgf10 Cre-ERT2 line (with the Cre-ERT2 cassette inserted in frame with the start codon of exon 1), called thereafter Fgf10 Ki-v1, to target FGF10Pos cells. While this line allowed fairly efficient and specific labeling of FGF10Pos cells during the embryonic stage, it failed to target these cells after birth, particularly in the postnatal lung, which has been the focus of our research. We report here the generation and validation of a new knock-in Fgf10 Cre-ERT2 line (called thereafter Fgf10 Ki-v2) with the insertion of the expression cassette in frame with the stop codon of exon 3. Fgf10 Ki-v2/+ heterozygous mice exhibited comparable Fgf10 expression levels to wild type animals. However, a mismatch between Fgf10 and Cre expression levels was observed in Fgf10 Ki-v2/+ lungs. In addition, lung and limb agenesis were observed in homozygous embryos suggesting a loss of Fgf10 functional allele in Fgf10 Ki-v2 mice. Bioinformatic analysis shows that the 3'UTR, where the Cre-ERT2 cassette is inserted, contains numerous putative transcription factor binding sites. By crossing this line with tdTomato reporter line, we demonstrated that tdTomato expression faithfully recapitulated Fgf10 expression during development. Importantly, Fgf10 Ki-v2 mouse is capable of significantly targeting FGF10Pos cells in the adult lung. Therefore, despite the aforementioned limitations, this new Fgf10 Ki-v2 line opens the way for future mechanistic experiments involving the postnatal lung.

Regulatory effect of mitoQ on the mtROS-NLRP3 inflammasome pathway in leptin-pretreated BEAS-2 cells

Obese asthma is a phenotype of asthma whose occurrence is gradually increasing in both adults and children. The majority of studies have demonstrated that obesity is a major risk factor for asthma and the effect of obesity on the lungs is considerable. NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome has been previously demonstrated to serve a role in obese asthma mediated by mitochondrial reactive oxygen species (mtROS). The aim of the present in vitro study was to investigate the effect of leptin on airway epithelial cells and the protective effect of the mitochondrial-targeted antioxidant mitoquinone (mitoQ). Human normal bronchial epithelial cell lines BEAS-2 cells were used and divided into 6 groups: Control group (negative control), DMSO group (solvent control), lipopolysaccharide (LPS) group (positive control), LPS + mitoQ group, Leptin group and Leptin + mitoQ group. CCK8 assay was used to establish the optimal concentration and incubation time of the drugs. mitoTracker probe and mitoSOX reagent were used to detect the integrity of mitochondrial membranes and the content of mtROS. mRNA expression levels were detected by reverse transcription-quantitative PCR analysis. It was revealed that the mitochondrial membrane was disrupted in the Leptin group, which recovered after treatment with mitoQ. As a result, the production of mitochondrial reactive oxygen species (mtROS) in the Leptin group was significantly increased (P<0.01), but following treatment with mitoQ, this overproduction of mtROS was significantly decreased to normal levels (P<0.01). Furthermore, the expression levels of NOD-, LRR- and pyrin domain-containing protein 3 NLRP3 and caspase-1 mRNA in the leptin-pretreated BEAS-2 cells were significantly increased compared with those in the control group (P<0.01), while they were decreased following mitoQ treatment (P<0.01). Taken together, these data suggested that leptin may promote airway inflammation partially through upregulating the mtROS-NLRP3 inflammasome signaling pathway in airway epithelial cells and mitoQ may be a potential treatment for obese asthma.

Fgf10/Fgfr2b Signaling Orchestrates the Symphony of Molecular, Cellular, and Physical Processes Required for Harmonious Airway Branching Morphogenesis

Airway branching morphogenesis depends on the intricate orchestration of numerous biological and physical factors connected across different spatial scales. One of the key regulatory pathways controlling airway branching is fibroblast growth factor 10 (Fgf10) signaling via its epithelial fibroblast growth factor receptor 2b (Fgfr2b). Fine reviews have been published on the molecular mechanisms, in general, involved in branching morphogenesis, including those mechanisms, in particular, connected to Fgf10/Fgfr2b signaling. However, a comprehensive review looking at all the major biological and physical factors involved in branching, at the different scales at which branching operates, and the known role of Fgf10/Fgfr2b therein, is missing. In the current review, we attempt to summarize the existing literature on airway branching morphogenesis by taking a broad approach. We focus on the biophysical and mechanical forces directly shaping epithelial bud initiation, branch elongation, and branch tip bifurcation. We then shift focus to more passive means by which branching proceeds, via extracellular matrix remodeling and the influence of the other pulmonary arborized networks: the vasculature and nerves. We end the review by briefly discussing work in computational modeling of airway branching. Throughout, we emphasize the known or speculative effects of Fgfr2b signaling at each point of discussion. It is our aim to promote an understanding of branching morphogenesis that captures the multi-scalar biological and physical nature of the phenomenon, and the interdisciplinary approach to its study.

Targeting Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension (BPD-PH): Potential Role of the FGF Signaling Pathway in the Development of the Pulmonary Vascular System

More than 50 years after the first description of Bronchopulmonary dysplasia (BPD) by Northway, this chronic lung disease affecting many preterm infants is still poorly understood. Additonally, approximately 40% of preterm infants suffering from severe BPD also suffer from Bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH), leading to a significant increase in total morbidity and mortality. Until today, there is no curative therapy for both BPD and BPD-PH available. It has become increasingly evident that growth factors are playing a central role in normal and pathologic development of the pulmonary vasculature. Thus, this review aims to summarize the recent evidence in our understanding of BPD-PH from a basic scientific point of view, focusing on the potential role of Fibroblast Growth Factor (FGF)/FGF10 signaling pathway contributing to disease development, progression and resolution.

Time-resolved mRNA and miRNA expression profiling reveals crucial coregulation of molecular pathways involved in epithelial-pneumococcal interactions

Streptococcus pneumoniae is a major causative agent of pneumonia worldwide and its complex interaction with the lung epithelium has not been thoroughly characterized. In this study, we exploited both RNA‐sequencing and microRNA (miRNA)‐sequencing approaches to monitor the transcriptional changes in human lung alveolar epithelial cells infected by S. pneumoniae in a time‐resolved manner. A total of 1330 differentially expressed (DE) genes and 45 DE miRNAs were identified in all comparisons during the infection process. Clustering analysis showed that all DE genes were grouped into six clusters, several of which were primarily involved in inflammatory or immune responses. In addition, target gene enrichment analyses identified 11 transcription factors that were predicted to link at least one of four clusters, revealing transcriptional coregulation of multiple processes or pathways by common transcription factors. Notably, pharmacological treatment suggested that phosphorylation of p65 is important for optimal transcriptional regulation of target genes in epithelial cells exposed to pathogens. Furthermore, network‐based clustering analysis separated the DE genes negatively regulated by DE miRNAs into two functional modules (M1 and M2), with an enrichment in immune responses and apoptotic signaling pathways for M1. Integrated network analyses of potential regulatory interactions in M1 revealed that multiple DE genes related to immunity and apoptosis were regulated by multiple miRNAs, indicating the coordinated regulation of multiple genes by multiple miRNAs. In conclusion, time‐series expression profiling of messenger RNA and miRNA provides a wealth of information for global transcriptional changes, and offers comprehensive insight into the molecular mechanisms underlying host–pathogen interactions.

MiR-574-5p alleviates sepsis-induced acute lung injury by regulating TRAF6/NF-κB pathway

Purpose: To investigate the protective effect of miR-574-5p pretreatment against acute lung injury (ALI) induced by sepsis.Methods: A male C57BL/6 mouse model of sepsis-induced ALI was established by cecal ligation and puncture (CLP) and treated with miR-574-5p agomir (intravenous injection, 80 mg/kg per day, 3 days). After that, blood and lung samples were obtained for histopathological observation. Myeloperoxidase (MPO) activity, inflammatory cell infiltration, and cytokine expression were analyzed. The target gene of miR-574-5p was predicted using TargetScan prediction, and verified by luciferase assay and western blot.Results: In sepsis-induced ALI mice model, downregulation of miR-574-5p was observed. Pretreatment of miR-574-5p significantly alleviated ALI by suppressing histological damage, and reducing MPO activity and inflammatory cell infiltration, as well as decreasing cytokine expression. The  underlying mechanism was that miR-574-5p targeted TNF receptor associated factor 6 (TRAF6) and suppressed the downstream NF-κB pathway. Moreover, TRAF6 overexpression reversed the effects of miR-574-5p on ALI.Conclusion: MiR-574-5p pretreatment suppresses inflammatory responses, thus reducing lung injury induced by sepsis in mice, partly via the regulation of TRAF6 and NF-κB pathway. Therefore, this approach can potentially be used for the clinical management of ALI in humans Keywords: Sepsis, Acute lung injury, MiR-574-5p, TRAF6, NF-κB pathway

Lipoxin A4 reduces hyperoxia-induced lung injury in neonatal rats through PINK1 signaling pathway

Bronchopulmonary dysplasia (BPD) is a common chronic lung disease in premature infants and is mainly caused by hyperoxia exposure and mechanical ventilation. Alveolar simplification, pulmonary vascular abnormalities and pulmonary inflammation are the main pathological changes in hyperoxic lung injury animals. Lipoxin A4 (LXA4) is an important endogenous lipid that can mediate the regression of inflammation and plays a role in acute lung injury and asthma. The purpose of this study was to evaluate the effects of LXA4 on inflammation and lung function in neonatal rats with hyperoxic lung injury and to explore the mechanism of the PINK1 pathway. After 85% oxygen exposure in newborn rats for 7 days, the BPD model was established. We found that LXA4 could significantly reduce cell and protein infiltration and oxidative stress in rat lungs, improve pulmonary function and alveolar simplification, and promote weight gain. LXA4 inhibited the expression of TNF-α, MCP-1 and IL-1β in serum and BALF from hyperoxic rats. Moreover, we found that LXA4 could reduce the expression of the PINK1 gene and down-regulate the expression of PINK1, Parkin, BNIP3L/Nix and the autophagic protein LC3B.These protective effects of LXA4 could be partially reversed by addition of BOC-2.Thus, we concluded that LXA4 can alleviate the airway inflammatory response, reduce the severity of lung injury and improve lung function in a hyperoxic rat model of BPD partly through the PINK1 signaling pathway.

Expression Levels of Predominant Adipokines and Activations of STAT3, STAT6 in an Experimental Mice Model of Obese Asthma

Obese asthma is a new asthma phenotype. The underlying mechanisms are not clearly understood. Leptin and adiponectin are two predominant adipokines produced by adipose tissue. Studies have demonstrated a role of leptin on regulating the Janus kinase/signal transducer and ativator of transcription protein (JAK/STAT) signaling pathway and STAT3, STAT6 were known to have essential role on inflammatory cytokines production. However, whether STAT3 and STAT6 are activated and related to leptin merit further investigation. The aim of this study was to investigate the expression levels of leptin/adiponectin ratio and the activations of STAT3 and STAT6 in the lungs of obese asthma mice. Experiments were carried out on male C57/B6J mice. The proteins in bronchoalveolar lavage fluid (BALF) were measured using ELISA. The expression levels of the transcriptional and translational factors in the lungs were examined using Quantitative Reverse Transcriptase Polymerase Chain reaction (qRT-PCR) and western blot. The expression levels of leptin in the BALF of normal weight group, asthma group, obese group and obese asthma group were 2.032±0.133, 5.375±0.123, 5.418±0.165 and 7.486±0.168, respectively. The expression of leptin in obese asthma group was the highest (p<0.05) ，while the expression of adiponectin the lowest (p<0.05). The expression level of P-STAT3 in the obese asthma group was 0.9244±0.014, and was significantly higher than three other groups (p<0.05). The expressions of P-STAT6 in three other groups were all significantly higher than normal weight group (p<0.05). Our data suggest that the function of leptin on the pulmonary inflammation of obese asthma may be partly through activating the STAT3 signaling pathway.  

Expression Levels of Predominant Adipokines and Activations of STAT3, STAT6 in an Experimental Mice Model of Obese Asthma

Obese asthma is a new asthma phenotype. The underlying mechanisms are not clearly understood. Leptin and adiponectin are two predominant adipokines produced by adipose tissue. Studies have demonstrated a role of leptin on regulating the Janus kinase/signal transducer and ativator of transcription protein (JAK/STAT) signaling pathway and STAT3, STAT6 were known to have essential role on inflammatory cytokines production. However, whether STAT3 and STAT6 are activated and related to leptin merit further investigation. The aim of this study was to investigate the expression levels of leptin/adiponectin ratio and the activations of STAT3 and STAT6 in the lungs of obese asthma mice. Experiments were carried out on male C57/B6J mice. The proteins in bronchoalveolar lavage fluid (BALF) were measured using ELISA. The expression levels of the transcriptional and translational factors in the lungs were examined using Quantitative Reverse Transcriptase Polymerase Chain reaction (qRT-PCR) and western blot. The expression levels of leptin in the BALF of normal weight group, asthma group, obese group and obese asthma group were 2.032±0.133, 5.375±0.123, 5.418±0.165 and 7.486±0.168, respectively. The expression of leptin in obese asthma group was the highest (p<0.05) ，while the expression of adiponectin the lowest (p<0.05). The expression level of P-STAT3 in the obese asthma group was 0.9244±0.014, and was significantly higher than three other groups (p<0.05). The expressions of P-STAT6 in three other groups were all significantly higher than normal weight group (p<0.05). Our data suggest that the function of leptin on the pulmonary inflammation of obese asthma may be partly through activating the STAT3 signaling pathway.

Adiponectin alleviates exacerbation of airway inflammation and oxidative stress in obesity-related asthma mice partly through AMPK signaling pathway

Adiponectin plays a role in asthma and obesity, but its effects and mechanism in obesity-related asthma remain elusive. This study aimed to evaluate the effects of adiponectin on airway inflammation and oxidative stress and to determine its mechanism in obesity-related asthma. Male C57BL6/J mice fed with a high-fat diet to induce obesity were sensitized and challenged with ovalbumin to induce asthma, and treated with adiponectin (1 mg/kg) and AMP-activated protein kinase (AMPK) inhibitor compound C (20 mg/kg) twice before the first ovalbumin challenge. We found exogenous adiponectin significantly reduced airway resistance, inflammatory infiltration in lung tissue, and cell counts in bronchoalveolar lavage fluid. Adiponectin inhibited great levels of eotaxin, myeloperoxidase, tumor necrosis factor-α, 8‑hydroxy‑2'‑deoxyguanosine, and nitric oxide in obesity-related asthma mice. Moreover, we found increased nuclear factor kappa B p65, inducible nitric oxide synthase and B-cell lymphoma 2 protein expression were down-regulated with adiponectin administration. Additionally, adiponectin elevated the lower levels of pAMPK and AMPK activity in lung tissue. These protective effects of adiponectin were reversed after treatment with the AMPK inhibitor compound C. Thus, we conclude that adiponectin alleviates exacerbation of airway inflammation and oxidative stress in a murine model of obesity-related asthma partly through AMPK signaling pathway.

MicroRNA-133a alleviates airway remodeling in asthtama through PI3K/AKT/mTOR signaling pathway by targeting IGF1R

Asthma is characterized by chronic inflammation, and long-term chronic inflammation leads to airway remodeling. But the potential regulatory mechanism of airway remodeling is not clearly understood, and there is still no effective way to prevent airway remodeling. Present studies have confirmed the role of microRNAs (miRNAs) in the development of disease, which is known as suppressing translation or degradation of messenger RNA (mRNA) at the posttranscriptional stage. In this study, we described the role of miRNA-133a in asthma and demonstrated it in regulating airway remodeling of asthma through the phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway by targeting IGF-1 receptor (IGF1R). IGF1R helps in mediating the intracellular signaling cascades. Asthmatic mice models were established by sensitization and Ovalbumin challenge. Adenovirus transfer vector carrying miR-133a or miR-133a sponge sequence was used to build the overexpression or downexpression of miR-133a modeling. Real-time polymerase chain reaction and Western blot were used to determine the alterations in the expression of miR-133a and mRNAs and their corresponding proteins. Results showed that miR-133a was downregulated in asthma. Upregulation of miR-133a expression in airway smooth muscle cells in vivo and in vitro could inhibit the activation of PI3K/AKT/mTOR pathway, and reduce the expression of α-smooth muscle actin (α-SMA), indicating that airway remodeling was inhibited. Functional studies based on luciferase reporter revealed miR-133a as a direct target of IGF1R mRNA. In conclusion, these data suggested that miR-133a regulated the expression of α-SMA through PI3K/AKT/mTOR signaling by targeting IGF1R. miR-133a plays a key role in airway remodeling of asthma and may serve as a potential therapeutic target for managing asthmatic airway remodeling.

Influence of gender on OVA-induced airway inflammation in C57/B6J mice on a high-fat diet

Overweight/obesity has been suggested as a risk factor for asthma development, and prospective studies have confirmed that high body weight precedes asthma symptoms. However, the nature of the association between overweight/obese status and asthma remains unclear. Animal models of obesity-related asthma are very useful for understanding disease pathophysiology. Although C57/B6J mice are the most widely used animal model for researching obesity-related asthma, gender differences are not always taken into consideration. Therefore, to explore the effect of gender on the development of obesity-related asthma, both female and male C57/B6J mice were used in this study. The mice were fed with a high-fat diet or a low-fat diet as control. Body weight, body length, liver weight, and Lee’s Index were used to evaluate obesity status, and lung histology, lung inflammatory cells infiltration, and inflammatory cytokines in bronchoalveolar lavage fluid (BALF) were examined for asthma evaluation. We found that the mean body weight of male mice on a high-fat diet gradually increased and was significantly higher than control male mice on a low-fat diet ( P < 0.01), while no significant differences were found between female mice at the end of 12 weeks of feeding. Furthermore, the obese asthma group female and male mice exhibited significantly high inflammatory cells infiltration than normal weight or obese female and male mice ( P < 0.01). However, the obese asthma group presented higher Neu infiltration, Th1 cytokine, and interferon gamma (IFNγ) concentrations in BALF than the asthma group in both the genders ( P < 0.01). In conclusion, both female and male mice are suitable for the obesity-related asthma model, although male mice might be more stable. Besides, obesity-related asthma is not Th2 type asthma.

High-fat-diet induces airway hyperresponsiveness partly through activating CD38 signaling pathway

CD38 is a plasma membrane bound multifunctional enzyme. It can be activated by inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-13, inducing calcium responses to agonist in airway smooth muscle cells (ASMC). Previous studies have found that high-fat-diet (HFD) induced obesity exhibited innate airway hyperresponsiveness (AHR). This study aimed to detect the effect of CD38 signaling pathway on the AHR of overweight/obese mice. The HFD-fed mice exhibited a significantly higher baseline airway resistance (Rn), and the increasing rates of Rn responded to increasing doses of methacholine compared with the LFD-fed mice. High-fat-diet increased CD38 expressions both in lung tissues and primary cultured ASMCs. Besides, preincubation with TNF-α led to a higher expression of CD38 protein and increased intracellular calcium in ASMC of the HFD-fed mice. Furthermore, CD38 gene knockdown through transfection of CD38 siRNA decreased the concentration of intracellular calcium. Additionally, the upregulations of CD38 protein and CD38 mRNA were also found in the lung tissues of HFD-fed mice challenged by ovalbumin (OVA). Collectively, our findings demonstrated a role of CD38 signaling pathway on the AHR of obesity and might be a potential therapeutic target for treating difficult-to-control obese asthma phenotype.

Role of SIRT1 in Streptococcus pneumoniae-induced human β-defensin-2 and interleukin-8 expression in A549 cell

Streptococcus pneumoniae is an important pathogen of pneumonia in human. Human alveolar epithelium acts as an effective barrier and is an active participant in host defense against invasion of bacterial by production of various mediators. Sirtuin 1 (SIRT1), the prototypic class III histone deacetylase, is involved in the molecular control of lifespans and immune responses. This study aimed at examining the role of SIRT1 in mediating S. pneumoniae-induced human β-defensin-2 (hBD2) and interleukin-8(IL-8) expression in the alveolar epithelial cell line A549 and the underlying mechanisms involved. A549 cells were infected with S. pneumoniae for indicated times. Exposure of A549 cells to S. pneumoniae increased the expressions of SIRT1 protein, hBD2 and IL-8 mRNA, and protein. The SIRT1 activator resveratrol enhanced S. pneumoniae-induced gene expression of hBD2 but decreased IL-8 mRNA levels. Blockade of SIRT1 activity by the SIRT1 inhibitors nicotinamide reduced S. pneumoniae-induced hBD2 mRNA expression but increased its stimulatory effects on IL-8 mRNA. S. pneumoniae-induced activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK). SIRT1 expression was attenuated by selective inhibitors of ERK and p38 MAPK. The hBD2 mRNA production was decreased by pretreatment with p38 MAPK inhibitor but not with ERK inhibitor, whereas the IL-8 mRNA expression was controlled by phosphorylation of ERK. These results suggest that SIRT1 mediates the induction of hBD2 and IL-8 gene expression levels in A549 cell by S. pneumoniae. SIRT1 may play a key role in host immune and defense response in A549.

PI3K and Notch signal pathways coordinately regulate the activation and proliferation of T lymphocytes in asthma

AIMS

In the present study, we determined whether Phosphoinositide 3-kinase (PI3K) and Notch signal pathways are involved in the expression of cyclinD1, cyclinA and p27kip1 which were key molecules in controlling cell cycling from CD4(+) T lymphocyte in animal model of asthma.

MAIN METHODS

Ovalbumin (OVA) sensitized murine model of asthma was used to investigate the expression of cyclin D1, cyclin A, and p27kip1 by splenic CD4(+) T lymphocytes. We further observed the effect of specific inhibitor of PI3K(LY294002) and specific inhibitor of Notch(DAPT) on the proliferation of such CD4(+) T lymphocytes.

KEY FINDINGS

We found that the expression of cyclinD1 and cyclinA was upregulated at both protein and mRNA levels in asthma group while p27kip1 was down-regulated. Both LY294002 and DAPT inhibit the proliferation of CD4(+) T lymphocytes in a time- and dose-dependent manner. Furthermore, LY294002 and DAPT have additive effect in down-regulation of cyclinD1 and upregulation of p27kip1. An upregulation of cyclinA, although not statistically significant, was also observed.

SIGNIFICANCE

These data suggested that PI3K signal pathway and Notch signal pathway may coordinately regulate the cell proliferation and differentiation processes through up-regulating cyclinD1 and down-regulating p27kip1 of CD4(+) T lymphocytes.

Urotensin upregulates transforming growth factor-β1 expression of asthma airway through ERK-dependent pathway

Airway smooth muscle cells (ASMCs) play a key role in the process of asthma airway remodeling. Urotensin II (UII) and transforming growth factor (TGF)-β are potent mitogens for ASMCs proliferation. The study was aimed to determine whether UII-upregulated TGF-β-mediated ASMCs proliferation and extracellular signal-regulated kinase (ERK) was required for such an effect. OVA-sensitized rats were challenged to induce asthma. Lung morphology and airway dynamic parameters were monitored. ASMCs from control and asthma rats were purified for the measurement of UII and TGF-β1 expression. In vitro experiments were conducted to determine the direct effect of UII on TGF-β1 expression by ASMCs. Finally, U0126, an ERK inhibitor was used to examine the role of ERK pathway in UII mediated TGF-β1 upregulation. We found that both UII and TGF-β1 were upregulated in asthma lung tissues. In vitro study on ASMCs further revealed that UII may render its effect on ASMCs cells through the upregulation of TGF-β1. Data also supported the conclusion that ERK pathway was required, but not sufficient in UII-induced TGF-β1 upregulation. The current study provides new evidence that UII is involved in the TGF-β mediated mitogenic effect on ASMCs. UII, at least partially, uses ERK pathway to render such effect.

Population fluctuations of light-attracted chrysomelid beetles in relation to supra-annual environmental changes in a Bornean rainforest

In Southeast Asian tropical rainforests, two events, severe droughts associated with the El Niño-Southern Oscillation and general flowering, a type of community-wide mass flowering, occur at irregular, supra-annual intervals. The relationship between these two supra-annual events and patterns of insect population fluctuations has yet to be clearly elucidated. Leaf beetles (Chrysomelidae) are major herbivores and flower-visitors of canopy trees, affecting their growth and reproduction and, in turn, affected by tree phenology; but their population fluctuations in the Southeast Asian tropics have not been extensively investigated. We examined population fluctuation patterns of the 34 most dominant chrysomelid species in relation to the two supra-annual events by conducting monthly light-trapping over seven years in a lowland dipterocarp forest in Borneo. Our results showed large community variation in population fluctuation patterns and a supra-annual (between-year) variation in abundance for most of the dominant chrysomelids that was significantly larger than the annual (within-year) variation. Specifically, in response to a severe drought in 1998, chrysomelid species exhibited different population responses. These results show that population fluctuations of individual species, rather than the entire assemblage, must be analyzed to determine the effects of changes in environmental conditions on the structure of insect assemblages in the tropics, especially in regions where supra-annual environmental changes are relatively more important than seasonal changes.

Basal cell carcinoma of the nose: an Australian and New Zealand radiation oncology patterns-of-practice study

Patients with a basal cell carcinoma (BCC) of the nose may be recommended radiotherapy (RT) with a wide variation in techniques and prescribed dose fractionation schedules between clinicians. The aim of this study was to ascertain variability in the patterns of practice among Australian and New Zealand radiation oncologists (ROs) when treating BCC arising on the nose. A postal survey was sent to 222 practising ANZ ROs detailing 12 different clinical scenarios of a BCC arising on the nose. The treatment selected for each scenario was analysed according to clinician's attitudes, training, experience and the availability of resources. The response rate was 74% (165/222) with 90 respondents treating non-melanoma skin cancer. Training was perceived to have a marked influence on treatment practice by most (79%). In total, 72% of ROs were 'very certain' in their choice of a dose fractionation schedule for obtaining local control and 61% for a satisfactory cosmetic outcome, respectively. Most (76%) favoured low-voltage photons over electrons as the optimal method of treatment, although for certain clinical scenarios most would use electrons. Dose fractionation schedules were highly variable with a lower total dose and hypofractionation favoured for older patients. Low-voltage photons were favoured for the T1 BCC and electrons for the T2 and T4 BCC. Nearly one-third of the ROs chose megavoltage photons for the T4 lesion. There is marked variation in treatment practices in terms of recommending RT over other treatment options, the choice of RT method, the dose fractionation schedule, the extent of field margins and the point of dose prescription.

47 SUCCESSFULLY PRODUCING CLONED MICE FROM SOMATIC CELLS OF AGED MICE VIA ESTABLISHED ntES CELL LINES

Recent nuclear transfer techniques have enabled us to produce cloned animals from somatic cell nuclei in a variety of animal species and are to date the only way to obtain offspring from infertile animals. Despite very aged mice often showing an infertile phenotype, the decreasing rate of cloning success with increased age makes it almost impossible to produce cloned mice or offspring from these animals. Other studies, however, have demonstrated that ES cell lines have been established from cloned blastocysts through somatic cell nuclear transfer (ntES cells), irrespective of sex, strains, or organs. These cells are subsequently capable of differentiating into all three germ layers in vitro, or even into spermatozoa and oocytes in chimeric mice. Thus, ntES cells have received considerable attention recently in regenerative medicine. Importantly, the success rate of establishing ntES cell lines from cloned blastocysts is ten times higher than that of producing cloned mice, which may allow us to establish ntES cell lines even from such 'unclonable' aged mice. ntES cells also have the potential to be a good donor source for nuclear transfer as they have the same DNA as their donor somatic cells and can indefinitely proliferate in their undifferentiated states. In this study, we attempted to establish ntES cell lines from aged mice and analyze their normality. We then tried to produce cloned mice via nuclear transfer using established ntES cell lines. We obtained donor cells from tail-tip fibroblast cells of BDF1 and BCF1 male and female mice that were over two years old. Following nuclear transfer, we transferred a proportion of the cleaved cloned embryos to pseudopregnant ICR female mice. The remaining embryos were cultured for 72 h, and cloned embryos that developed into morulae or blastocysts were plated on feeder cells. We then examined all established ntES cell lines for normality by Oct4 and Nanog expression using immunofluorescence staining and pluripotency by chimeric mice formation, for which ntES cells were injected into fertilized ICR embryos. Finally, we attempted to produce cloned mice from the nuclei of these ntES cell lines. In each experiment, 25, 37, 73, 63, and 75 cloned embryos from aged mice tail-tip cells were used in attempts to produce cloned mice, and 20, 20, 27, 35, and 40 cloned embryos were used to derive ntES cell lines, respectively. No cloned mice were obtained by direct nuclear transfer of the aged mice tail-tip cells; however, we were successful in establishing ntES cell lines from all experiments, with an establishment rate between 10 and 25%. All established ntES cell lines expressed Oct4 and Nanog and contributed to somatic cells in chimeric mice. Some chimeric mice produced offspring derived from ntES cells after mating. We were also able to produce cloned mice even from a 2-year-old and a 9-month-old BCF1 male mouse by nuclear transfer using ntES cells as donor nuclei. These results clearly show that normal ntES cell lines can be established from infertile, aged mice and this technique can now be used to produce offspring, irrespective of donor conditions.

Matrix metalloproteinases and aggrecanases cleave aggrecan in different zones of normal cartilage but colocalize in the development of osteoarthritic lesions in STR/ort mice

OBJECTIVE

To map aggrecan cleavage by matrix metalloproteinases (MMPs) and aggrecanases in normal murine tibial articular cartilage (CBA strain) and in the development of spontaneous osteoarthritis (OA) in the STR/ort mouse and to assess the influence of sex hormone status on these conditions in gonadectomized STR/ort mice.

METHODS

The distributions of neoepitopes of aggrecan generated by MMP (VDIPEN) and aggrecanase (NITEGE) cleavage were investigated by immunohistochemistry.

RESULTS

VDIPEN neoepitope was detected mainly in the pericellular matrix of deep-zone chondrocytes in normal tibial cartilage from STR/ort and CBA mice. In early OA, VDIPEN immunostaining also localized to the pericellular matrix of chondrocytes at the site of the lesion. With increasing severity of OA lesions, VDIPEN immunostaining was also detected in the interterritorial matrix, close to the site of the lesion. In contrast, NITEGE mapped most strongly to the pericellular matrix of upper-zone chondrocytes in normal tibial cartilage. As with VDIPEN, NITEGE was strongly expressed in the pericellular matrix at the site of early OA lesions. With advancing OA, NITEGE colocalized with VDIPEN in both the pericellular and interterritorial matrices of chondrocytes adjacent to OA lesions and in those of the deep zones. Hormone status did not appear to influence the development of OA or the distribution of aggrecan neoepitopes in STR/ort mice.

CONCLUSION

MMP- and aggrecanase-generated neoepitopes map predominantly to different regions in normal murine tibial cartilage. However, both groups of enzymes generate increased amounts of neoepitopes in pericellular and interterritorial matrix adjacent to histopathologic lesions of OA. Aggrecan degradation and the development of OA appear to be independent of sex hormone status in this model.

Treatment planning and delivery of intensity-modulated radiation therapy for primary nasopharynx cancer

PURPOSE

To implement intensity-modulated radiation therapy (IMRT) for primary nasopharynx cancer and to compare this technique with conventional treatment methods.

METHODS AND MATERIALS

Between May 1998 and June 2000, 23 patients with primary nasopharynx cancer were treated with IMRT delivered with dynamic multileaf collimation. Treatments were designed using an inverse planning algorithm, which accepts dose and dose-volume constraints for targets and normal structures. The IMRT plan was compared with a traditional plan consisting of phased lateral fields and a three-dimensional (3D) plan consisting of a combination of lateral fields and a 3D conformal plan.

RESULTS

Mean planning target volume (PTV) dose increased from 67.9 Gy with the traditional plan, to 74.6 Gy and 77.3 Gy with the 3D and IMRT plans, respectively. PTV coverage improved in the parapharyngeal region, the skull base, and the medial aspects of the nodal volumes using IMRT and doses to all normal structures decreased compared to the other treatment approaches. Average maximum cord dose decreased from 49 Gy with the traditional plan, to 44 Gy with the 3D plan and 34.5 Gy with IMRT. With the IMRT plan, the volume of mandible and temporal lobes receiving more than 60 Gy decreased by 10-15% compared to the traditional and 3D plans. The mean parotid gland dose decreased with IMRT, although it was not low enough to preserve salivary function.

CONCLUSION

Lower normal tissue doses and improved target coverage, primarily in the retropharynx, skull base, and nodal regions, were achieved using IMRT. IMRT could potentially improve locoregional control and toxicity at current dose levels or facilitate dose escalation to further enhance locoregional control.

Calculating structures and free energies of complex molecules: combining molecular mechanics and continuum models

A historical perspective on the application of molecular dynamics (MD) to biological macromolecules is presented. Recent developments combining state-of-the-art force fields with continuum solvation calculations have allowed us to reach the fourth era of MD applications in which one can often derive both accurate structure and accurate relative free energies from molecular dynamics trajectories. We illustrate such applications on nucleic acid duplexes, RNA hairpins, protein folding trajectories, and protein-ligand, protein-protein, and protein-nucleic acid interactions.

Vasoactive and proliferative effects of parathyroid hormone and parathyroid hormone-related peptide on human vascular smooth muscle

BACKGROUND

Hyperparathyroidism is associated with an increased incidence of hypertension and cardiovascular disease. Experiments in rats suggest that this results from desensitization of the normally inhibitory effects of parathyroid hormone-related peptide (PTHrP) on vascular smooth muscle cells (VSMCs) by previous exposure to parathyroid hormone (PTH).

METHODS

Isometric tension in vitro was measured in segments of vessels obtained at neck surgery from six normotensive patients with hyperparathyroidism and 12 eucalcaemic controls undergoing thyroid surgery. Vessels were precontracted with noradrenaline to allow the vasodilatory effects of PTH and PTHrP to be observed. Human VSMCs were cultured in 0.5, 5 and 15 per cent serum with or without PTH (10(-11) to 10(-7) nmol l-(1)) and proliferation was assessed by cell counts after 14 days.

RESULTS

Vasodilatation of arterial segments produced by both PTH 20 nmol l(-1) and PTHrP 100 nmol l(-1) did not differ significantly between control and hyperparathyroidism groups (P > 0.08, Mann-Whitney U test). Vasodilatation by PTHrP was not reduced by preincubation of vessels in vitro with PTH 50 nmol l(-1) for 1 h (P > 0.36, Wilcoxon test). No effects of PTH on serum-induced proliferation of human VSMCs were observed.

CONCLUSION

These data imply that homologous desensitization to PTHrP is not implicated in the pathogenesis of vascular disease in patients with hyperparathyroidism.