Immunostimulatory DNA sequences inhibit respiratory syncytial viral load, airway inflammation, and mucus secretion

Anti-inflammatory effects of reticuline on the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathway in a mouse model of obesity-associated asthma

BACKGROUND

Asthma associated with obesity is a chronic disease characterized by earlier airway remodeling, severe wheezing, and increased insensitivity to hormone therapy. Reticuline, a bioactive compound of Magnoliae Flos, exerts anti-inflammatory activity and can inhibit neutrophil recruitment. Thus, this study investigated the role of reticuline in obesity-related asthma.

METHODS

The BALB/c mice fed a low-fat diet (LFD) and high-fat diet (HFD) were intranasally challenged with house dust mites (HDMs) or ovalbumin (OVA). Reticuline (0.25 mg/kg) was administrated into mice by intragastrical gavage. Airway hyper-responsiveness was examined after the final challenge. Body weight was measured, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected. The number of inflammatory cells in BALF was estimated. Histological changes were assessed by performing hematoxylin-eosin staining, and production of proinflammatory cytokines and IgE was examined by ELISA kits. Related pathways were studied with western blotting.

RESULTS

Reticuline suppressed airway resistance and inflammatory infiltration in lung tissue and reduced inflammatory cell recruitment in BALF in obesity mice with asthma. Additionally, the levels of IL-17A, IL-1β, IL-5, macrophage inflammatory protein 2, and regulated on activation, normal T cell expressed and secreted in the lung were reduced by reticuline. Mechanistically, reticuline inactivated the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways in obesity-related asthma.

CONCLUSION

Reticuline alleviates airway inflammation in obesity-related asthma by inactivating the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways.

Transcriptomics reveals apigenin alleviates airway inflammation and epithelial cell apoptosis in allergic asthma via MAPK pathway

Persistent chronic inflammation of the lungs and airway remodeling are important pathological features that cannot be ignored in patients with chronic asthma. Apigenin (API) is a natural small molecule compound with good anti-inflammatory and antioxidant activity that has been widely reported in recent years, but its role in chronic asthma is not well defined. Our study began with oral gavage intervention using API (10, 20 mg/kg) or dexamethasone (DEX, 2 mg/kg) in a BALB/c mouse model of ovalbumin (OVA) sensitization. Different doses of API intervention effectively reduced airway resistance in the administered group. Additionally, inflammation was downregulated, mucus secretion was reduced, and airway remodeling was inhibited in the API intervention group compared with the model group. Asthma-related inflammatory cytokines, such as IgE, IL-4, IL-5, IL-13, and IL-17, were downregulated in alveolar lavage fluid. Moreover, the apoptosis level of the administered group was found to be lower than that of the model group in the Tunel staining experiment. By analyzing transcriptome sequencing results, we found that API may exert anti-inflammatory and anti-apoptotic effects by inhibiting the MAPK pathway. Our subsequent results supported this conclusion, showing that the phosphorylation levels of ERKs, JNKs, and p38 MAPKs were inhibited in the administered group relative to the model group. Downstream expression of the apoptosis-related protein B-cell lymphoma-2 (Bcl-2) was upregulated, and the expression of Bcl-2-associated × protein (Bax) and cleaved caspase-3 was downregulated. To further investigate the specific mechanism by which API acted, we established an in vitro model with house dust mite (HDM) stimulation, using API (10, 20 μM) for administration intervention. The results showed that API was able to improve cell viability, inhibit ROS production, and reverse HDM-induced decreases in mitochondrial membrane potential (MMP) and apoptosis in airway epithelial cells via the MAPK pathway.

Kisspeptin regulates airway hyperresponsiveness and remodeling in a mouse model of asthma

Asthma is a multifactorial disease of origin characterized by airway hyperresponsiveness (AHR) and airway remodeling. Several pieces of evidence from other pathologies suggest that Kisspeptins (Kp) regulate cell proliferation, migration, and invasion, mechanisms that are highly relevant to asthma. Our recent in vitro studies show Kp-10 (active peptide of Kp), via its receptor, KISS1R, inhibits human airway smooth muscle cell proliferation. Here, we hypothesize a crucial role for Kp-10 in regulating AHR and airway remodeling in vivo. Utilizing C57BL/6J mice, we assessed the effect of chronic intranasal Kp-10 exposure on mixed allergen (MA)-induced mouse model of asthma. MA-challenged mice showed significant deterioration of lung function compared to those exposed to vehicle (DPBS); Kp-10 treatment significantly improved the MA-altered lung functions. Mice treated with Kp-10 alone did not show any notable changes in lung functions. MA-exposed mice showed a significant reduction in KISS1R expression as compared to vehicle alone. MA-challenged mice showed significant alterations in immune cell infiltration in the airways and remodeling changes. Proinflammatory cytokines were significantly increased upon MA exposure, an effect abrogated by Kp-10 treatment. Furthermore, biochemical and histological studies showed Kp-10 exposure significantly reduced MA-induced smooth muscle mass and soluble collagen in the lung. Overall, our findings highlight the effect of chronic Kp-10 exposure in regulating MA-induced AHR and remodeling. © 2023 The Pathological Society of Great Britain and Ireland.

Myocd regulates airway smooth muscle cell remodeling in response to chronic asthmatic injury

Abnormal growth of airway smooth muscle cells is one of the key features in asthmatic airway remodeling, which is associated with asthma severity. The mechanisms underlying inappropriate airway smooth muscle cell growth in asthma remain largely unknown. Myocd has been reported to act as a key transcriptional coactivator in promoting airway-specific smooth muscle development in fetal lungs. Whether Myocd controls airway smooth muscle remodeling in asthma has not been investigated. Mice with lung mesenchyme-specific deletion of Myocd after lung development were generated, and a chronic asthma model was established by sensitizing and challenging the mice with ovalbumin for a prolonged period. Comparison of the asthmatic pathology between the Myocd knockout mice and the wild-type controls revealed that abrogation of Myocd mitigated airway smooth muscle cell hypertrophy and hyperplasia, accompanied by reduced peri-airway inflammation, decreased fibrillar collagen deposition on airway walls, and attenuation of abnormal mucin production in airway epithelial cells. Our study indicates that Myocd is a key transcriptional coactivator involved in asthma airway remodeling. Inhibition of Myocd in asthmatic airways may be an effective approach to breaking the vicious cycle of asthmatic progression, providing a novel strategy in treating severe and persistent asthma. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Apigenin ameliorates non-eosinophilic inflammation, dysregulated immune homeostasis and mitochondria-mediated airway epithelial cell apoptosis in chronic obese asthma via the ROS-ASK1-MAPK pathway

BACKGROUND

Obese asthma is one of the important asthma phenotypes that have received wide attention in recent years. Excessive oxidative stress and different inflammatory endotypes may be important reasons for the complex symptoms, frequent aggravation, and resistance to traditional treatments of obese asthma. Apigenin (API), is a flavonoid natural small molecule compound with good anti-inflammatory and antioxidant activity in various diseases and proved to have the potential efficacy to combat obese asthma.

METHODS

In vivo, this study fed C57BL/6 J mice with high-fat diets(HFD)for 12 weeks and then stimulated them with OVA for 6 weeks to establish a model of chronic obese asthma, while different doses of oral API or dexamethasone were used for therapeutic interventions. In vitro, this study used HDM to stimulate human bronchial cells (HBEs) to establish the model and intervened with API or Selonsertib (SEL).

RESULTS

This study clarified that OVAinduced a type of mixed granulocytic asthma with elevated neutrophils and eosinophils in obese male mice fed with long-term HFD, which also exhibited mixed TH17/TH1/TH2 inflammation. Apigenin effectively suppressed this complex inflammation and acted as a regulator of immune homeostasis. Meanwhile, apigenin reduced AHR, inflammatory cell infiltration, airway epithelial cell apoptosis, airway collagen deposition, and lung oxidative stress via the ROS-ASK1-MAPK pathway in an obese asthma mouse model. In vitro, this study found that apigenin altered the binding status of TRAF6 to ASK1, inhibited ASK1 phosphorylation, and protected against ubiquitin-dependent degradation of ASK1, suggesting that ROS-activated ASK1 may be an important target for apigenin to exert anti-inflammatory and anti-apoptotic effects. To further verify the intervention mechanism, this study clarified that apigenin improved cell viability and mitochondrial function and inhibited apoptosis by interfering with the ROS-ASK1-MAPK pathway.

CONCLUSIONS

This study demonstrates for the first time the therapeutic effect of apigenin in chronic obese asthma and further clarifies its potential therapeutic targets. In addition, this study clarifies the specificity of chronic obese asthma and provides new options for its treatment.

Louki Zupa decoction attenuates the airway inflammation in acute asthma mice induced by ovalbumin through IL-33/ST2-NF-κB/GSK3β/mTOR signalling pathway

CONTEXT

Asthma is a common respiratory system disease. Louki Zupa decoction (LKZP), a traditional Chinese medicine, presents a promising efficacy against lung diseases.

OBJECTIVE

To investigate the pathogenic mechanism of asthma and reveal the intervention mechanism of LKZP.

MATERIALS AND METHODS

Forty-eight female Balb/c mice were randomly divided into 6 groups: normal control group (NC), ovalbumin (OVA)/saline asthma model group, OVA/LL group, OVA/LM group, OVA/LH group and OVA/DEX group (n = 8 per group). The asthmatic mice were modelled through intraperitoneal injecting and neutralizing OVA. LKZP decoction was administrated by gavage at the challenge stage for seven consecutive days (2.1, 4.2 and 8.4 g/kg/day). We investigated the change in lung function, airway inflammation, mucus secretion and TH-1/TH-2-related cytokines. We further verify the activated status of the IL-33/ST2/NF-κB/GSK3β/mTOR signalling pathway.

RESULTS

LKZP was proved to improve asthmatic symptoms, as evidenced by the down-regulated airway resistance by 36%, 58% and 53% (p < 0.01, p < 0.001 vs. OVA/saline group), up-regulated lung compliance by 102%, 114% and 111%, decreased airway inflammation and mucus secretion by 33%, 40% and 33% (p < 0.001 vs. OVA/saline group). Moreover, the content of cytokines in BALF related to airway allergy (such as IgE) and T helper 1/T helper 2 cells (like IL-2, IL-4, IL-5, IL-13, TNF-α and IFN-γ), were also markedly reduced by 13-65% on LKZP intervention groups compared with model group. Mechanistic research revealed that the IL-33/ST2-NF-κB/GSK3β/mTOR signalling pathway was activated in the OVA/saline group and LKZP significantly down-regulated this pathway.

DISCUSSION AND CONCLUSION

LKZP improves lung function, airway inflammation, mucus secretion and correct immune imbalance by intervening with the IL-33/ST2-NF-κB/GSK3β/mTOR signalling pathway, presenting a promising therapeutic choice for asthma.

Has2 Regulates the Development of Ovalbumin-Induced Airway Remodeling and Steroid Insensitivity in Mice

HAS2 is a member of the gene family encoding the hyaluronan synthase 2, which can generate high-molecular-weight hyaluronan (HMW-HA). Our previous study identified HAS2 as a candidate gene for increased susceptibility to adult asthma. However, whether HAS2 dysfunction affects airway remodeling and steroid insensitivity is still limited. Therefore, this study aimed to clarify the Has2 dysfunction, triggering severe airway remodeling and steroid insensitivity in a murine model of asthma. Has2 heterozygous-deficient (Has2^+/−) mice and their wild-type littermates have been evaluated in a model of chronic ovalbumin (OVA) sensitization and challenge. Mice present a higher sensitivity to OVA and higher IL-17 release as well as eosinophilic infiltration. RNA sequencing demonstrated the downregulation of EIF2 signaling pathways, TGF-β signaling pathways, and heat shock proteins with Th17 bias in Has2^+/−-OVA mice. The combined treatment with anti-IL-17A antibody and dexamethasone reduces steroid insensitivity in Has2^+/−-OVA mice. Has2 attenuation worsens eosinophilic airway inflammation, airway remodeling, and steroid insensitivity. These data highlight that HAS2 and HMW-HA are important for controlling intractable eosinophilic airway inflammation and remodeling and could potentially be exploited for their therapeutic benefits in patients with asthma.

Effect of an Antagonistic Peptide of CCR5 on the Expression of Autophagy-related Genes and β-Arrestin 2 in Lung Tissues of Asthmatic Mice

Purpose

The mechanisms of CC chemokine receptor 5 (CCR5) in the process of autophagy remain unknown. In this study, we examined the role of HY peptide, which is an antagonistic peptide specifically binding the second extracellular loop of CCR5, in the expression of autophagy genes and β-arrestin 2 in lung tissues of asthmatic mice.

Methods

Experimental asthmatic mice were treated with HY peptide and dexamethasone sodium phosphate (Dex). Airway inflammation, autophagy-related genes, autophagic vacuoles (AVs) and β-arrestin 2 were examined in lung tissues, and the correlation between β-arrestin 2 and LC3 expression was assessed.

Results

HY peptide and Dex treatments alleviate airway inflammation. The expression of autophagy-related genes, such as BECN1, ATG5 and LC3, was decreased in the lung tissues of the asthmatic mice. However, HY peptide and Dex treatments increased the expression of these genes as well as the formation of AVs. Additionally, the expression of the β-arrestin 2 protein was significantly increased in the HY peptide-treated group, and positive cells expressing β-arrestin 2 were mainly located in the membrane and cytoplasm of bronchial epithelial cells. The β-arrestin 2 expression was positively correlated with the expression of LC3 in the model and HY peptide-treated groups.

Conclusions

HY peptide inhibits airway inflammation, autophagic dysfunction exists in asthmatic mice, and targeting HY peptide increases the expression of autophagy-related genes. Thus, β-arrestin 2 may participate in the mechanisms underlying these processes.

A novel protective role of sacubitril/valsartan in cyclophosphamide induced lung injury in rats: impact of miRNA-150-3p on NF-κB/MAPK signaling trajectories

Cyclophosphamide (CP) is a chemotherapeutic agent that induces oxidative stress causing multiple organ damage. Sacubitril/valsartan, is a combined formulation of neprilysin inhibitor (sacubitril) and angiotensin II receptor blocker (valsartan), that induces the protective effect of brain natriuretic peptide. The aim of the current study is to investigate the prophylactic impacts of sacubitril/valsartan versus valsartan against CP-induced lung toxicity in rats. Rats were assigned randomly into 6 groups; control; received corn oil (2 ml/kg/day; p.o. for 6 days), sacubitril/valsartan (30 mg/kg; p.o. for 6 days), valsartan (15 mg/kg; p.o. for 6 days), CP (200 mg/kg; i.p. on day 5), sacubitril/valsartan + CP (30 mg/kg; p.o. for 6 days, 200 mg/kg; i.p. single dose on day 5, respectively), valsartan + CP (15 mg/kg; p.o. for 6 days, 200 mg/kg; i.p. single dose on day 5, respectively). Both sacubitril/valsartan and valsartan produced a significant decrease in the inflammation and fibrosis markers in the BALF, in comparison with the CP group. Both sacubitril/valsartan and valsartan produced an apparent decrease in the relative genes expression of miR-150-3p and NF-κB, as well as a significant decrease in the relative expression of P38 and ERK1/2 MAPKs and an increase in the relative gene expression of Nrf-2, compared to CP group. Intriguingly, sacubitril/valsartan , showed subtle superiority in almost all investigated parameters, compared to valsartan. In conclusion, sacubitril/valsartan effectively abrogated the CP induced lung inflammation and fibrosis, providing a potential promising protection that could be linked to their ability to inhibit miR-150-3p via inhibition of NF-κB and MAPK signaling pathways.

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.

Ketamine Inhalation Ameliorates Ovalbumin-Induced Murine Asthma by Suppressing the Epithelial-Mesenchymal Transition

BACKGROUND Asthma accounts for 0.4% of all deaths worldwide, a figure that increases annually. Ketamine induces bronchial smooth muscle relaxation, and increasing evidence suggests that its anti-inflammatory properties might protect against lung injury and ameliorate asthma. However, there is a lack of evidence of the usefulness and mechanism of ketamine in acute asthma exacerbation. This study aimed to analyze the therapeutic effects and mechanism of action of ketamine on acute ovalbumin (OVA)-induced murine asthma. MATERIAL AND METHODS In vivo, BALB/c mice with OVA-induced asthma were treated with or without ketamine (25 or 50 mg/mL). Serum, lung sections, and mononuclear cell suspensions from the lung were collected for histological, morphometric, immunofluorescence, microRNA, quantitative polymerase chain reaction, regulatory T cell identification, cytokine, and Western blotting analyses. In vitro, bronchial epithelial cells were cultured to analyze the effect and mechanism of ketamine on epithelial-mesenchymal transition (EMT) and transforming growth factor-β (TGF-β) signaling. RESULTS The inhalation of ketamine 25 or 50 mg/mL markedly suppressed OVA-induced airway hyper-responsiveness and airway inflammation, significantly increased the percentage of CD4+CD25+ T cells, and significantly decreased OVA-induced up-regulation of TGF-β1 and the EMT. MiR-106a was present at higher amounts in OVA-induced lung samples and was suppressed by ketamine treatment. The in vitro results showed that TGF-β1-induced EMT was suppressed by ketamine via miR-106a level regulation. CONCLUSIONS Ketamine ameliorates lung fibrosis in OVA-induced asthmatic mice by suppressing EMT and regulating miR-106a level, while ketamine inhalation might be a new therapeutic approach to the treatment of allergic asthma.

γ-Secretase Inhibitor Alleviates Acute Airway Inflammation of Allergic Asthma in Mice by Downregulating Th17 Cell Differentiation

T helper 17 (Th17) cells play an important role in the pathogenesis of allergic asthma. Th17 cell differentiation requires Notch signaling. γ-Secretase inhibitor (GSI) blocks Notch signaling; thus, it may be considered as a potential treatment for allergic asthma. The aim of this study was to evaluate the effect of GSI on Th17 cell differentiation in a mouse model of allergic asthma. OVA was used to induce mouse asthma model in the presence and absence of GSI. GSI ameliorated the development of OVA-induced asthma, including suppressing airway inflammation responses and reducing the severity of clinical signs. GSI also significantly suppressed Th17-cell responses in spleen and reduced IL-17 levels in serum. These findings suggest that GSI directly regulates Th17 responses through a Notch signaling-dependent pathway in mouse model of allergic asthma, supporting the notion that GSI is a potential therapeutic agent for the treatment of allergic asthma.

Protective effect of curcumin on acute airway inflammation of allergic asthma in mice through Notch1-GATA3 signaling pathway

Curcumin, a natural product derived from the plant Curcuma longa, has been found to have anti-inflammatory, antineoplastic and antifibrosis effects. It has been reported that curcumin attenuates allergic airway inflammation in mice through inhibiting NF-κB and its downstream transcription factor GATA3. It also has been proved the antineoplastic effect of curcumin through down-regulating Notch1 receptor and its downstream nuclear transcription factor NF-κB levels. In this study, we aimed to investigate the anti-inflammatory effect of curcumin on acute allergic asthma and its underlying mechanisms. 36 male BALB/c mice were randomly divided into four groups (normal, asthma, asthma+budesonide and asthma+curcumin groups). BALF (bronchoalveolar lavage fluid) and lung tissues were analyzed for airway inflammation and the expression of Notch1, Notch2, Notch3, Notch4 and the downstream transcription factor GATA3. Our findings showed that the levels of Notch1 and Notch2 receptors were up-regulated in asthma group, accompanied by the increased expression of GATA3. But the expression of Notch2 receptor was lower than Notch1 receptor. Curcumin pretreatment improved the airway inflammatory cells infiltration and reversed the increasing levels of Notch1/2 receptors and GATA3. Notch3 receptor was not expressed in all of the four groups. Notch4 receptor protein and mRNA expression level in the four groups had no significant differences. The results of the present study suggested that Notch1 and Notch2 receptor, major Notch1 receptor, played an important role in the development of allergic airway inflammation and the inhibition of Notch1–GATA3 signaling pathway by curcumin can prevent the development and deterioration of the allergic airway inflammation. This may be a possible therapeutic option of allergic asthma.

Roles of lipoxin A4 receptor activation and anti-interleukin-1β antibody on the toll-like receptor 2/mycloid differentiation factor 88/nuclear factor-κB pathway in airway inflammation induced by ovalbumin

Previous studies investigating the role of toll-like receptors (TLRs) in asthma have been inconclusive. It has remained elusive whether the toll-like receptors (TLR2)/mycloid differentiation factor 88 (MyD88)/nuclear factor (NF)-κB signaling pathway is involved in lipoxin A4 (LXA4)-induced protection against asthma. Therefore, the present study investigated whether ovalbumin (OVA)-induced airway inflammation is mediated by upregulation of the TLR2/MyD88/NF-κB signaling pathway, and whether it proceeds via the inhibition of the activation of the LXA4 receptor and anti-interleukin (IL)-1β antibodies. Mice with airway inflammation induced by OVA administration were treated with or without a LXA4 receptor agonist, BML-111 and anti-IL-1β antibody. Serum levels of IL-1β, IL-4, IL-8 and interferon-γ (IFN-γ) were assessed, and levels of IL-1β, IL-4, IL-8 and OVA-immunoglobulin (Ig)E, as well as leukocyte counts in the bronchoalveolar lavage fluid (BALF) were measured. Pathological features and expression of TLR2, MyD88 and NF-κB in the lungs were analyzed. Expression of TLR2 and MyD88, and activation of NF-κB in leukocytes as well as levels of IL-4, IL-6 and IL-8 released from leukocytes exposed to IL-1β were assessed. OVA treatment increased the levels of IL-1β, IL-4 and IL-8 in the serum and BLAF, the number of leukocytes and the levels of OVA-IgE in the BALF, the expression of TLR2 and MyD88, and the activation of NF-κB in the lung. These increments induced by OVA were inhibited by treatment with BML-111 and anti-IL-1β antibodies. Treatment of the leukocytes with BML-111 or TLR2 antibody, or MyD88 or NF-κB inhibitor, all blocked the IL-1β-triggered production of IL-4, IL-6 and IL-8 and activation of NF-κB. Treatment of the leukocytes with BML-111 or TLR2 antibody suppressed IL-1β-induced TLR2 and MyD88 expression. The present study therefore suggested that OVA-induced airway inflammation is mediated by the TLR2/MyD88/NF-κB pathway. IL-1β has a pivotal role in the airway inflammation and upregulation of the TLR2/MyD88/NF-κB pathway induced by OVA. BML-111 and anti-IL-1β antibody restrains the OVA-induced airway inflammation via downregulation of the TLR2/MyD88/NF-κB pathway.

The effects of budesonide on angiogenesis in a murine asthma model

INTRODUCTION

The aim of this study is to determine the effects and mechanisms of budesonide on angiogenesis in a murine asthma model.

MATERIAL AND METHODS

MURINE ASTHMA MODELS WERE ESTABLISHED AND MICE WERE DIVIDED INTO THREE GROUPS: the model group (OVA-sensitized and challenged mice), the BUD group (budesonide-treated mice) and the PBS group (normal control mice). Mice in the BUD group were administered with inhaled budesonide (100 µg/kg) daily. The effects on airway inflammation, angiogenesis, expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were examined.

RESULTS

Administration of budesonide ameliorated allergic airway inflammation (2.90 ±0.18 vs. 4.80 ±0.20, p < 0.01) and significantly reduced the percentage vascularity (0.78 ±0.14 vs. 2.83 ±0.90, p < 0.01) compared with those in the asthmatic model mice. It also reduced the expression of HIF-1α (immunohistochemistry results: 71.70 ±1.40 vs. 89.60 ±0.79, p < 0.001; western blotting results: 0.88 ±0.41 vs. 0.97 ±0.47, p < 0.05), as well as that of VEGF (immunohistochemistry results: 26.30 ±1.03 vs. 93.30 ±1.54, p < 0.001; western blotting results: 1.12 ±0.22 vs. 2.08 ±0.30, p < 0.01). Percentage vascularity had positive correlation with both HIF-1α (r = 0.785, p < 0.01) and VEGF (r = 0.693, p < 0.01) expression. Furthermore, there is positive relationship between HIF-1α and VEGF expression (r = 0.641, p < 0.05).

CONCLUSIONS

The results demonstrate that budesonide has an important inhibitory effect on angiogenesis in asthma. Inhaled administration of budesonide achieved anti-angiogenic activity through inhibition of HIF-1α and VEGF expression. The results support a potential anti-remodeling role for budesonide in the treatment of human asthma.

Nucleoprotein nanostructures combined with adjuvants adapted to the neonatal immune context: a candidate mucosal RSV vaccine

Background

The human respiratory syncytial virus (hRSV) is the leading cause of severe bronchiolitis in infants worldwide. The most severe RSV diseases occur between 2 and 6 months-of-age, so pediatric vaccination will have to be started within the first weeks after birth, when the immune system is prone to Th2 responses that may turn deleterious upon exposure to the virus. So far, the high risk to prime for immunopathological responses in infants has hampered the development of vaccine. In the present study we investigated the safety and efficacy of ring-nanostructures formed by the recombinant nucleoprotein N of hRSV (N^SRS) as a mucosal vaccine candidate against RSV in BALB/c neonates, which are highly sensitive to immunopathological Th2 imprinting.

Methodology and Principal Findings

A single intranasal administration of N^SRS with detoxified E.coli enterotoxin LT(R192G) to 5–7 day old neonates provided a significant reduction of the viral load after an RSV challenge at five weeks of age. However, neonatal vaccination also generated an enhanced lung infiltration by neutrophils and eosinophils following the RSV challenge. Analysis of antibody subclasses and cytokines produced after an RSV challenge or a boost administration of the vaccine suggested that neonatal vaccination induced a Th2 biased local immune memory. This Th2 bias and the eosinophilic reaction could be prevented by adding CpG to the vaccine formulation, which, however did not prevent pulmonary inflammation and neutrophil infiltration upon viral challenge.

Conclusions/Significance

In conclusion, protective vaccination against RSV can be achieved in neonates but requires an appropriate combination of adjuvants to prevent harmful Th2 imprinting.

The traditional Chinese herbal formula ASHMI inhibits allergic lung inflammation in antigen-sensitized and antigen-challenged aged mice

BACKGROUND

Although asthma is typically characterized as a childhood disease, it can develop later in life. Older asthmatic patients may be at increased risk for corticosteroid adverse effects. We developed a novel traditional Chinese medicine to treat asthma called antiasthma simplified herbal medicine intervention (ASHMI). Herbal products may offer safer adjunctive treatment for older asthmatic patients.

OBJECTIVE

To investigate the effects of ASHMI on characteristics of allergic asthma in an aged mouse model of asthma.

METHODS

BALB/c mice (6 weeks old [young] and 6, 12, and 18 months old [aged]) received ASHMI treatment before and during intraperitoneal ovalbumin sensitization and intratracheal challenges. The control groups were untreated, age-matched, ovalbumin-sensitized and ovalbumin-challenged mice (ovalbumin mice) and naive mice. After the final antigen challenge, airway pressure (defined as the time-integrated change in peak airway pressure) after acetylcholine provocation was measured, representing airway hyperresponsiveness, and bronchoalveolar lavage fluid, sera, lung tissues for histologic analysis, messenger RNA, and collagen were collected.

RESULTS

Mean time-integrated change in peak airway pressure values in 6-week-old and 6-, 12-, and 18-month-old ASHMI ovalbumin mice were significantly reduced compared with those of age-matched, nontreated ovalbumin mice. Bronchoalveolar lavage fluid eosinophil numbers were significantly lower in all ASHMI ovalbumin mice. Treatment with ASHMI of young and aged ovalbumin mice resulted in significantly decreased lung inflammation, detected via hematoxylin-eosin staining; airway mucous cell metaplasia, determined by means of periodic acid-Schiff staining; and messenger RNA copy numbers of the mucin gene MUC5AC. Levels of ovalbumin specific IgE and the T(H)2 cytokines interleukin 4 (IL-4), IL-5, and IL-13 in lung and splenocyte cultures were reduced. Interferon gamma secretion was increased. Treatment with ASHMI reduced collagen production.

CONCLUSION

Treatment with ASHMI reduces several features of asthma in aged antigen-sensitized and antigen-challenged mice.

CpG DNA: Trigger of Sepsis, Mediator of Protection, or Both?

Unmethylated CpG motifs are prevalent in bacterial but not vertebrate genomic DNAs and activate immune cells that express the TLR9 receptor. This triggers the production of reactive oxygen species and the secretion of proinflammatory cytokines and chemokines. Under some conditions these effects can result in the systemic inflammatory response syndrome. Under other conditions, the immune stimulatory effects of CpG motifs can protect against pathogen challenge and initiate prophylactic and therapeutic innate and adaptive immune responses.

Immunotherapeutic applications of CpG oligodeoxynucleotide TLR9 agonists

Toll-like receptor 9 (TLR9) agonists have demonstrated substantial potential as vaccine adjuvants, and as mono- or combination therapies for the treatment of cancer and infectious and allergic diseases. Commonly referred to as CpG oligodeoxynucleotides (ODN), TLR9 agonists directly induce the activation and maturation of plasmacytoid dendritic cells and enhance differentiation of B cells into antibody-secreting plasma cells. Preclinical and early clinical data support the use of TLR9 agonists as vaccine adjuvants, where they can enhance both the humoral and cellular responses to diverse antigens. In mouse tumor models TLR9 agonists have shown activity not only as monotherapy, but also in combination with multiple other therapies including vaccines, antibodies, cellular therapies, other immunotherapies, antiangiogenic agents, radiotherapy, cryotherapy, and some chemotherapies. Phase I and II clinical trials have indicated that these agents have antitumor activity as single agents and enhance the development of antitumor T-cell responses when used as therapeutic vaccine adjuvants. CpG ODN have shown benefit in multiple rodent and primate models of asthma and other allergic diseases, with encouraging results in some early human clinical trials. Although their potential clinical contributions are enormous, the safety and efficacy of these TLR9 agonists in humans remain to be determined.

Bacterial extracts for the prevention of acute exacerbations in chronic obstructive pulmonary disease: a point of view

Given the high prevalence of chronic obstructive pulmonary disease (COPD), the impact of exacerbations on quality of life, and the costs incurred, effective ways for the prevention of exacerbations, and for reductions in the severity and duration of COPD symptoms are needed. Bacterial immunostimulation has been advocated as a management strategy in COPD for the purposes of preventing acute exacerbations. In particular, it suggests that the use of oral multicomponent vaccines may reduce the severity and duration of acute episodes. The way in which bacterial extracts may exert their effects is not fully understood although a number of possible specific mechanisms have been suggested. Given the high prevalence of COPD worldwide and the high cost of acute exacerbations, some cost-effectiveness analyses suggest that bacterial immunostimulants may become a key element in the improved control of this condition. Nonetheless, larger and longer clinical trials are needed to investigate efficacy before oral vaccination could be recommended as part of the routine clinical management of COPD, mainly in advanced COPD. It remains also to be investigated whether this protective effect may be additive to the other treatments. In any case, it is well known that for Streptococcus pneumoniae, non-typable Haemophilus influenzae and Moraxella catarrhalis, recurrent infections occur because of strain heterogeneity. Therefore, a single or even multiple strain vaccine with a killed whole cell formulation is possibly not the ideal vaccine. Moreover, the method of inactivation can affect the immunogenicity of essential antigens through denaturation. For this reason, the efficacy of bacterial immunostimulants should not only be assessed but also compared.

Effect of ageing on pulmonary inflammation, airway hyperresponsiveness and T and B cell responses in antigen-sensitized and -challenged mice

BACKGROUND

The effect of ageing on several pathologic features of allergic asthma (pulmonary inflammation, eosinophilia, mucus hypersecretion), and their relationship with airway hyperresponsiveness (AHR) is not well characterized.

OBJECTIVE

To evaluate lung inflammation, mucus metaplasia and AHR in relationship with age in murine models of allergic asthma comparing young and older mice.

METHODS

Young (6 weeks) and older (6, 12, 18 months) BALB/c mice were sensitized and challenged with ovalbumin (OVA). AHR and bronchoalveolar fluid (BALF), total inflammatory cell count and differential were measured. To evaluate mucus metaplasia, quantitative PCR for the major airway mucin-associated gene, MUC-5AC, from lung tissue was measured, and lung tissue sections stained with periodic acid-Schiff (PAS) for goblet-cell enumeration. Lung tissue cytokine gene expression was determined by quantitative PCR, and systemic cytokine protein levels by ELISA from spleen-cell cultures. Antigen-specific serum IgE was determined by ELISA.

RESULTS

AHR developed in both aged and young OVA-sensitized/challenged mice (OVA mice), and was more significantly increased in young OVA mice than in aged OVA mice. However, BALF eosinophil numbers were significantly higher, and lung histology showed greater inflammation in aged OVA mice than in young OVA mice. MUC-5AC expression and numbers of PAS+ staining bronchial epithelial cells were significantly increased in the aged OVA mice. All aged OVA mice had increased IL-5 and IFN-gamma mRNA expression in the lung and IL-5 and IFN-gamma protein levels from spleen cell cultures compared with young OVA mice. OVA-IgE was elevated to a greater extent in aged OVA mice.

CONCLUSIONS

Although pulmonary inflammation and mucus metaplasia after antigen sensitization/challenge occurred to a greater degree in older mice, the increase in AHR was significantly less compared with younger OVA mice. Antigen treatment produced a unique cytokine profile in older mice (elevated IFN-gamma and IL-5) compared with young mice (elevated IL-4 and IL-13). Thus, the airway response to inflammation is lessened in ageing animals, and may represent age-associated events leading to different phenotypes in response to antigen provocation.

Antiinfective applications of toll-like receptor 9 agonists

The innate immune system detects pathogens by the presence of highly conserved pathogen-expressed molecules, which trigger host immune defenses. Toll-like receptor (TLR) 9 detects unmethylated CpG dinucleotides in bacterial or viral DNA, and can be stimulated for therapeutic applications with synthetic oligodeoxynucleotides containing immune stimulatory "CpG motifs." TLR9 activation induces both innate and adaptive immunity. The TLR9-induced innate immune activation can be applied in the prevention or treatment of infectious diseases, and the adaptive immune-enhancing effects can be harnessed for improving vaccines. This article highlights the current understanding of the mechanism of action of CpG oligodeoxynucleotides, and provides an overview of the preclinical data and early human clinical trial results, applying these TLR9 agonists in the field of infectious diseases.

Modulation of cytokine production and enhancement of cell viability by TLR7 and TLR9 ligands during anthrax infection of macrophages

Inhalation of Bacillus anthracis, a bioterrorism agent, results in a high mortality rate despite appropriate antibiotic therapy. Macrophages appear to be a key factor in B. anthracis pathogenesis. The burst of pro-inflammatory cytokines from macrophages could be a major cause of death in anthrax. However, preactivation of Toll-like receptors (TLRs) could modify the host response. TLR ligands stimulate the release of activating cytokines but may also down-modulate the subsequent deleterious cytokine response to pathogens. We developed a cell culture model to measure macrophage responses to B. anthracis spores and bacilli. We found that germination from spores to bacilli produced a substantial stimulus for the secretion of the cytokines IL-6, TNF-alpha, IL-10, and IL-12 p40. Our studies showed that pretreatment of mouse macrophages with the TLR9 ligand ISS-1018, or the TLR7 ligands R-848 and IT-37, results in a substantial decrease in the subsequent secretion of IL-6 and TNF-alpha in response to B. anthracis infection of macrophages. Furthermore, the TLR7 and TLR9 ligands significantly decreased anthrax-induced cytotoxicity in the macrophages. These findings suggest that TLR ligands may contribute to the enhancement of innate immunity in B. anthracis infection by suppressing potentially deleterious pro-inflammatory cytokine responses and by improving macrophage viability.

Therapeutic potential of Toll-like receptor 9 activation

In the decade since the discovery that mouse B cells respond to certain unmethylated CpG dinucleotides in bacterial DNA, a specific receptor for these 'CpG motifs' has been identified, Toll-like receptor 9 (TLR9), and a new approach to immunotherapy has moved into the clinic based on the use of synthetic oligodeoxynucleotides (ODN) as TLR9 agonists. This review highlights the current understanding of the mechanism of action of these CpG ODN, and provides an overview of the preclinical data and early human clinical trial results using these drugs to improve vaccines and treat cancer, infectious disease and allergy/asthma.

Stimulation of innate immune responses by CpG oligodeoxynucleotide in newborn lambs can reduce bovine herpesvirus-1 shedding

Stimulation of the innate immune system is potentially very important in neonates who have an immature adaptive immune system and vaccination cannot be used to reduce the risk of infection. CpG oligodeoxynucleotide (ODN) can stimulate innate immune responses in newborn chickens and mice, but similar studies are lacking in other mammalian species. We have shown previously that CpG ODN can both stimulate an acute-phase immune response and induce the antiviral effector molecule, 2'5'-A synthetase, in adult sheep. Therefore, the immunostimulatory activity of A class and B class CpG ODN was evaluated in newborn lambs, and the capacity of CpG ODN-induced responses to reduce viral shedding was evaluated following aerosol challenge with the respiratory pathogen, bovine herpesvirus-1 (BHV-1). In vitro CpG ODN stimulation of peripheral blood mononuclear cells (PBMC) isolated from newborn lambs (3-5 days old) and adult sheep induced equivalent CpG-specific proliferative responses and interferon-alpha (IFN-alpha) secretion. CpG ODN-induced IFN-alpha secretion by neonatal PBMCs was, however, significantly (p < 0.01) enhanced 6 days after subcutaneous (s.c.) injection of 100 microg/kg CpG ODN 2007. Newborn lambs injected s.c. with B class CpG ODN 2007 or the inverted GpC control ODN formulated in 30% Emulsigen (MVP Laboratories, Ralston, NE) displayed CpG ODN-specific increases in body temperature (p < 0.0001), serum 2'5'-A synthetase activity (p = 0.0015), and serum haptoglobin (p = 0.07). CpG ODN-treated lambs also displayed a transient reduction in viral shedding on day 2 postinfection (p < 0.05), which correlated (p < 0.03) with serum 2'5'-A synthetase levels on the day of viral challenge. These observations confirmed that CpG ODNs effectively activate innate immune responses in newborn lambs and CpG ODN-induced antiviral responses correlated with a reduction in viral shedding.

Deletion of CCR1 attenuates pathophysiologic responses during respiratory syncytial virus infection

The role of chemokines in chronic inflammatory responses are central to the recruitment of particular subsets of leukocytes. In the present studies, we have examined the role of CCR1 in the developing pathogenesis of respiratory syncytial virus (RSV) in the lungs of infected BALB/c mice. Although we did not observe significant differences in clearance of RSV, we were able to identify decreased pathophysiologic responses in CCR1(-/-) mice. CCR1(-/-) mice displayed a significant reduction in both airway hyperresponsiveness and mucus production that corresponded to significant increases in IFN-gamma and CXCL10. The goblet cell hyper/metaplasia and the expression of mucus-associated gene, gob5, were correspondingly reduced in the CCR1(-/-) mice. In addition, the Western blot analysis of gob5 protein indicated that CCR1(-/-) mice have virtually no up-regulation of the protein at day 6 of infection compared with wild-type-infected mice. Results from bone marrow chimeric mice indicated that partial reconstitution of the response could be achieved in the CCR1(-/-) mice with wild-type bone marrow cells, suggesting that these cells have a role in the response. However, transplanting of CCR1(-/-) bone marrow into wild-type mice did demonstrate an incomplete deficit in RSV-induced responses, indicating that CCR1(+) parenchymal cells may also play a significant role in the process. Thus, the presence of CCR1 appears to have a significant role in the development of detrimental airway physiologic responses during RSV infection. These data suggest that CCR1 may be a potential target during detrimental pulmonary responses during infection.

Treatment With AM3 Restores Defective T-Cell Function in COPD Patients

BACKGROUND

Lymphocyte alterations have been associated with an increased prevalence of acute respiratory infections in COPD patients. AM3 is an oral immunomodulator that normalizes the defective functions of peripheral blood natural killer and phagocytic cells in COPD patients and improves their health-related quality of life.

OBJECTIVES

To characterize putative systemic abnormalities of the T-cell compartment in COPD patients, and to investigate whether AM3 can restore such abnormalities.

DESIGN

The study was a randomized, prospective, double-blind, placebo-controlled trial in a cohort of COPD patients. The results were also compared to those of nonsmoker and ex-smoker healthy control subjects.

SETTING

Outpatient departments of four hospitals.

PATIENTS

Seventy COPD patients were randomized to receive either AM3 or a placebo orally for 90 consecutive days. Populations of 36 healthy nonsmokers and 36 healthy ex-smokers were used as control subjects.

MEASUREMENTS

Peripheral blood mononuclear cell (PBMC) proliferation and production of interleukin (IL)-2, IL-4, IL-12p40, tumor necrosis factor-alpha, and interferon (IFN)-gamma proteins in response to the T-cell polyclonal mitogens were assessed at baseline and at the end of treatment.

RESULTS

The proliferative response was significantly decreased in COPD patients. Decreased production of IFN-gamma was the only defect in the profiles of the cytokine measures, and was selectively observed in COPD patients, but not in nonsmoker and ex-smoker healthy control subjects. Treatment with AM3 significantly restored the PBMC proliferative response to polyclonal mitogens and significantly promoted stimulated IFN-gamma production in these patients. The normalization of these proliferative responses was not related to significant variations in the numbers of peripheral blood monocytes, CD3+, CD4+, CD8+ cells or of any major naïve/memory/activated T-cell subset. The increased IFN-gamma production in the AM3 study arm was associated with an increase in the mean of number of IFN-gamma molecules produced per CD8+ T cells.

CONCLUSIONS

PBMCs of COPD patients showed clear functional T-lymphocyte abnormalities that are rescued by AM3 treatment.

Hyperresponsiveness to inhaled but not intravenous methacholine during acute respiratory syncytial virus infection in mice

Background

To characterise the acute physiological and inflammatory changes induced by low-dose RSV infection in mice.

Methods

BALB/c mice were infected as adults (8 wk) or weanlings (3 wk) with 1 × 10⁵ pfu of RSV A2 or vehicle (intranasal, 30 μl). Inflammation, cytokines and inflammatory markers in bronchoalveolar lavage fluid (BALF) and airway and tissue responses to inhaled methacholine (MCh; 0.001 – 30 mg/ml) were measured 5, 7, 10 and 21 days post infection. Responsiveness to iv MCh (6 – 96 μg/min/kg) in vivo and to electrical field stimulation (EFS) and MCh in vitro were measured at 7 d. Epithelial permeability was measured by Evans Blue dye leakage into BALF at 7 d. Respiratory mechanics were measured using low frequency forced oscillation in tracheostomised and ventilated (450 bpm, flexiVent) mice. Low frequency impedance spectra were calculated (0.5 – 20 Hz) and a model, consisting of an airway compartment [airway resistance (Raw) and inertance (Iaw)] and a constant-phase tissue compartment [coefficients of tissue damping (G) and elastance (H)] was fitted to the data.

Results

Inflammation in adult mouse BALF peaked at 7 d (RSV 15.6 (4.7 SE) vs. control 3.7 (0.7) × 10⁴ cells/ml; p < 0.001), resolving by 21 d, with no increase in weanlings at any timepoint. RSV-infected mice were hyperresponsive to aerosolised MCh at 5 and 7 d (PC₂₀₀ Raw adults: RSV 0.02 (0.005) vs. control 1.1 (0.41) mg/ml; p = 0.003) (PC₂₀₀ Raw weanlings: RSV 0.19 (0.12) vs. control 10.2 (6.0) mg/ml MCh; p = 0.001). Increased responsiveness to aerosolised MCh was matched by elevated levels of cysLT at 5 d and elevated VEGF and PGE₂ at 7 d in BALF from both adult and weanling mice. Responsiveness was not increased in response to iv MCh in vivo or EFS or MCh challenge in vitro. Increased epithelial permeability was not detected at 7 d.

Conclusion

Infection with 1 × 10⁵ pfu RSV induced extreme hyperresponsiveness to aerosolised MCh during the acute phase of infection in adult and weanling mice. The route-specificity of hyperresponsiveness suggests that epithelial mechanisms were important in determining the physiological effects. Inflammatory changes were dissociated from physiological changes, particularly in weanling mice.

Anti-SARS-CoV immunity induced by a novel CpG oligodeoxynucleotide

To develop CpG oligodeoxynucleotides (CpG ODNs) based therapy for prevention and treatment of severe acute respiratory syndrome (SARS), we selected a novel CpG ODN (BW001), which displays B-type CpG ODN structure feature at the 5′ and A-type CpG ODN structure feature at the 3′, and tested for its anti-SARS-CoV activity. We found that the supernatants of human PBMCs stimulated by BW001 significantly protected Vero cells from SARS-CoV infection. BW001 could stimulate human PBMCs and pDCs to secrete high level of IFN-α and promote human PBMCs and B cells to proliferate. Furthermore, we demonstrated that BW001 could activate CD19⁺ B cells and CD56⁺ NK cells in human PBMCs. In addition, BW001 could enhance NK cytotoxicity and IFN-γ secretion in human PBMCs. Together, BW001 represents a novel type of CpG ODN and may have potential for the development of treatment and prevention for SARS as well as other viral associated diseases.

Immunostimulatory sequences of DNA and conjugates in the treatment of allergic rhinitis

Therapeutic strategies based on the use of immunostimulatory sequences of DNA containing a CpG motif (also known as ISS DNA, or CpG DNA) are focused on minimizing the allergenicity of immunotherapy while improving its effectiveness. Several ISS DNA-based methods of immunization (ISS DNA alone, ISS DNA conjugated to a protein allergen) have shown promise in animal models of asthma, and some of these ISS DNA-based therapies have entered clinical trials. These ongoing clinical trials will help to determine whether any of these ISS DNA-based therapies are safe and effective to use in subjects with allergic rhinitis and asthma.

Local therapy with CpG motifs in a murine model of allergic airway inflammation in IFN-beta knock-out mice

Background

CpG oligodeoxynucleotides (CpG-ODN) are capable of inducing high amounts of type I IFNs with many immunomodulatory properties. Furthermore, type-I IFNs have been proposed to play a key role in mediating effects of CpG-ODN. The precise role of IFN-β in the immunomodulatory effects of CpG-ODN is not known.

Objective

Here, we aimed to elucidate the role of IFN-β in the anti-allergic effect of CpG motifs.

Methods

We assessed the immune response in OVA-primed/OVA-challenged IFN-β knockout (-/-) mice compared to wild type (WT) control, after intranasal and systemic treatment with synthetic CpG motifs.

Results

Vaccination with CpG-ODN reduced the number of cells in airways of OVA-sensitized WT but not IFN-β-/- mice. Although airway eosinophilia was reduced in both treated groups, they were significantly higher in IFN-β^-/- mice. Other inflammatory cells, such as lymphocytes and macrophages were enhanced in airways by CpG treatment in IFN-β-/- mice. The ratio of IFN-γ/IL-4 cytokines in airways was significantly skewed to a Th1 response in WT compared to IFN-β^-/- group. In contrast, IL-4 and IgE were reduced with no differences between groups. Ag-specific T-cell proliferation, Th1-cytokines such as IFN-γ, IL-2 and also IL-12 were significantly lower in IFN-β-/- mice. Surprisingly, we discovered that intranasal treatment of mice with CpG-ODN results in mild synovitis particularly in IFN-β-/- mice.

Conclusion

Our results indicate that induction of Th1 response by therapy with CpG-ODN is only slightly and partially dependent on IFN-β, while IFN-β is not an absolute requirement for suppression of airway eosinophilia and IgE. Furthermore, our finding of mild synovitis is a warning for possible negative effects of CpG-ODN vaccination.

Stimulation via Toll-like receptor 9 reduces Cryptococcus neoformans-induced pulmonary inflammation in an IL-12-dependent manner

Cytosine-phosphate-guanosine-containing oligodeoxynucleotides (CpG ODN) are important vaccine adjuvants that promote Th1-type immune responses. Cryptococcus neoformans is a serious human pathogen that replicates in the lung but may disseminate systemically leading to meningitis, particularly in immunocompromised individuals. Immunization of susceptible C57BL/6 mice with CpG ODN deviates the immune response from a Th2- toward a Th1-type response following infection with C. neoformans. CpG also induces IL-12, TNF, MCP-1 and macrophage nitric oxide production. CD4(+) and CD8(+) T cells producing IFN-gamma increase in frequency, while those producing IL-5 decrease. More importantly, pulmonary eosinophilia is significantly reduced, an effect that depends on IL-12 and CD8(+) T cells but not NK cells. CpG treatment also reduces the burden of C. neoformans in the lung, an effect that is IL-12-, NK cell- and T cell-independent and probably reflects a direct effect of CpG on pathogen opsonization or an enhancement of macrophage antimicrobial activity. An equivalent beneficial effect is also observed when CpG ODN treatment is delivered during established cryptococcal disease. This is the first study documenting that promotion of lung TLR9 signaling using synthetic agonists enhances host defense. Activation of innate immunity has clear therapeutic potential and may even be beneficial in patients with acquired immune deficiency.

Immunostimulatory DNA reverses established allergen-induced airway remodeling

To determine whether immunostimulatory sequences of DNA (ISS) can reverse established airway remodeling, mice that had developed airway remodeling following 3 mo of repetitive OVA challenges, were treated with ISS for 1-3 mo. Systemic administration of ISS to mice that had already developed established airway remodeling significantly reduced the degree of airway collagen deposition (assessed by lung collagen content, peribronchial trichrome staining, and immunostaining with anticollagen type III and type V Abs). ISS reduced bronchoalveolar lavage and lung levels of TGF-beta1 and reduced the number of TGF-beta1-positive eosinophils and TGF-beta1-positive mononuclear cells recruited to the airway. In vitro studies demonstrated that ISS inhibited TGF-beta1 expression by macrophages (RAW 264.7 cell line and bone marrow-derived macrophages). In addition, ISS significantly reduces lung levels of expression of the chemokine thymus- and activation-regulated chemokine, as well as the number of peribronchial CD4(+) lymphocytes that express Th2 cytokines that promote peribronchial fibrosis. Overall, these studies demonstrate that ISS can reverse features of airway collagen deposition by reducing levels of lung TGF-beta1, as well as by reducing levels of the chemokine thymus- and activation-regulated chemokine and the numbers of peribronchial CD4(+) lymphocytes that drive the ongoing Th2 immune response.

Effects of primary and secondary low-grade respiratory syncytial virus infections in a murine model of asthma

BACKGROUND

Respiratory syncytial virus (RSV) infection is known to develop and exacerbate asthma in young children. In adult, RSV causes recurrent but asymptomatic infections. However, the impact of asymptomatic RSV infection on adult asthma is yet to be determined. The present study is designed to determine the effects of primary and secondary low-grade RSV infections on allergic airway inflammation in a murine model of allergic asthma.

METHODS

A low-grade RSV (2 x 10(3) plaque-forming units/mouse) was inoculated, and this caused neither pulmonary inflammation nor symptoms but induced significant IFN-gamma production in thoracic lymph nodes. To investigate interaction between low-grade virus and Dermatophagoides farinae (Df), airway hyper-responsiveness, lung inflammation and cytokine production from thoracic lymph nodes were compared after primary and secondary low-grade RSV infections in four groups of mice; control, Df allergen-sensitized, RSV-infected and Df-sensitized RSV-infected mice. A direct comparison between low- and high-grade RSV infections was also performed in primary infection. To investigate the role of IL-5 during secondary RSV infection, anti-IL-5 monoclonal antibody (anti-IL-5 mAb) was injected in mice and similar parameters were compared in four groups of mice.

RESULTS

Primary high-grade RSV infection increased allergen-induced airway inflammation, while primary low-grade RSV infection attenuated allergen-induced airway inflammation concomitant with significant IFN-gamma production in lung-draining lymph nodes. In marked contrast, secondary low-grade RSV infection increased both IFN-gamma and IL-5 production, resulting in exacerbation of allergen-induced airway inflammation. Anti-IL-5 mAb treatment in secondary low-grade RSV infection and Df allergen-sensitized mice attenuated virus and allergen-induced airway inflammation.

CONCLUSIONS

Low-grade RSV infection per se does not cause pulmonary inflammation, whereas it induces a significant immunological response in the allergen-sensitized host. These results indicate that subclinical and recurrent RSV infection may play an important role in exacerbation and maintenance of asthma in adults, wherein IL-5 is critically involved.

Current and emerging nonsteroidal anti-inflammatory therapies targeting specific mechanisms in asthma and allergy

Today inhaled corticosteroids (ICS) are regarded as the first-line controller anti-inflammatory treatment in the management of asthma. However, there is an increasing awareness of the risk of long-term adverse effects of ICS and that asthma is not only an organ-specific disease but also a systemic and small airway disease. This thinking has called for systemic treatment alternatives to treat asthma targeting more disease-specific mechanisms without influencing normal physiologic functions. Blocking of disease-specific mediators is a mechanism utilized by anti-leukotrienes and anti-immunoglobulin E treatment, each proven to be effective in both asthma and allergic rhinitis.Different cytokine-modifying strategies have been tested in clinical trials with variable results, some disappointing and some encouraging. Anti-interleukin (IL)-5 monoclonal antibody treatment effectively reduces the number of eosinophils locally in the airways and in peripheral blood in asthmatic patients. Unfortunately, this marked effect on eosinophils was not associated with an improvement in bronchial hyperresponsiveness and/or symptoms. Clinical trials with a recombinant soluble IL-4 receptor have been somewhat more successful at improving asthma control and allowing reduction of ICS therapy in asthma. Treatment with recombinant IL-12 had an effect on bronchial hyperresponsiveness and eosinophilic response, but was associated with unacceptable adverse effects. Other interesting cytokine-modulating treatments include those targeting IL-9, IL-10, IL-12 and IL-13.Immune-modulating treatment with bacterial antigens represents another strategy, originating from the hypothesis that some bacterial infections guide the immune system towards a T helper (Th) type 1 immune response. Mycobacterium vaccae, Bacille Calmette-Guerin (BCG) and immunostimulatory DNA sequences have all been tested in clinical trials, with encouraging results. Future asthma and allergy treatment will probably include not only one but also two or more disease-modifying agents administered to the same patient.

Immunostimulatory DNA Inhibits Transforming Growth Factor-β Expression and Airway Remodeling

Immunostimulatory sequences of DNA (ISS) inhibit eosinophilic airway inflammation, Th2 responses, and airway hyperreactivity (AHR) in mouse models of acute ovalbumin (OVA)-induced airway inflammation. To determine whether ISS inhibits airway remodeling, we developed a mouse model of airway remodeling in which OVA-sensitized mice were repeatedly exposed to intranasal OVA administration for 1-6 mo. Mice chronically exposed to OVA developed sustained eosinophilic airway inflammation and sustained AHR to methacholine compared with control mice. In addition, the mice chronically exposed to OVA developed features of airway remodeling, including thickening of the peribronchial smooth muscle layer, peribronchial myofibroblast accumulation, expression of the profibrotic growth factor transforming growth factor-beta, and subepithelial collagen deposition (assessed by quantitation of the area of peribronchial trichrome staining using image analysis, and immunostaining with anti-collagen V antibodies). Administration of ISS systemically every other week significantly inhibited the development of AHR, eosinophilic inflammation, airway mucus production, and importantly, airway remodeling in mice chronically exposed to OVA for 3-6 mo. In addition, ISS significantly reduced bronchoalveolar lavage and lung levels of the profibrotic cytokine transforming growth factor-beta. These studies demonstrate that ISS prevents not only Th2-mediated airway inflammation in response to acute allergen challenge, but also airway remodeling associated with chronic allergen challenge.

Cytokine response patterns, exposure to viruses, and respiratory infections in the first year of life

Daycare attendance and siblings are associated with viral-induced wheezing in children. Preexisting immunologic factors may influence the expression of viral infections in infancy, and in turn, recurrent infections may influence the development of immune responses. A total of 285 children were enrolled in the Childhood Origins of Asthma Project at birth and followed for at least 1 year. Cord blood and 1-year mononuclear cells were stimulated with phytohemagglutinin, and cytokine-response profiles were measured by enzyme-linked immunosorbent assay. Nasal lavage was performed for moderate to severe respiratory illnesses. Daycare attendance and/or siblings significantly increased the likelihood of contracting respiratory syncytial virus (1.5-1.6-fold increase) and rhinovirus (1.8-2.1-fold increase), and increased the risk of rhinovirus-induced wheezing (14-18% vs. 2%, p = 0.011). Cord blood IFN-gamma responses were inversely related to the frequency of viral respiratory infections (r(s) = -0.11, p = 0.05), and more significant for subjects with high exposure to other children (r(s) = -0.27, p = 0.028). The interval change in infantile IFN-gamma responses correlated positively with the frequency of viral infections in infancy (r(s) = 0.12, p = 0.047). These data suggest that neonatal IFN-gamma responses may influence antiviral activity, or may represent a marker of antiviral immunity maturation. Conversely, the frequency of viral infections in infancy can influence IFN-gamma responses.

CD40 ligand (CD154) improves the durability of respiratory syncytial virus DNA vaccination in BALB/c mice

Respiratory syncytial virus (RSV) infection is the single most important cause of serious acute respiratory illness in children <1 year of age worldwide, and is associated with life-threatening pneumonia or bronchiolitis in the elderly. Current vaccine strategies include live, attenuated virus, subunit and DNA vaccines, however, none have been sufficiently safe, or shown to induce satisfactory long-term immunity, thus immune modulators are being considered to enhance the effectiveness of RSV vaccines. In this study, we examine CD40 ligand (CD40L) as an immune modulator to enhance the durability of DNA vaccines encoding RSV F and/or G glycoproteins in BALB/c mice. The addition of CD40L to DNA vaccines encoding the F glycoprotein enhanced virus clearance and some aspects of the immune response to RSV challenge, suggesting that CD40L may enhance the durability of RSV DNA vaccines.

Resolution of airway inflammation following ovalbumin inhalation: comparison of ISS DNA and corticosteroids

In this study we have compared the therapeutic effect of the administration of immunostimulatory DNA sequences (ISS) with that of corticosteroids on the resolution of airway inflammation and airway hyperreactivity (AHR) in a mouse model. Mice which had already developed significant levels of eosinophilic airway inflammation 24 h after allergen challenge were then treated with either ISS or corticosteroids, and the effect on AHR and airway inflammation assessed 6 d later. ISS inhibited AHR as effectively as corticosteroids. Combination therapy with ISS and corticosteroids was more effective than monotherapy with either ISS or corticosteroids in inhibiting AHR. In ovalbumin-challenged mice, levels of bronchoalveolar lavage (BAL) eosinophils were significantly reduced with either ISS or corticosteroids. ISS induced significant levels of BAL interferon-gamma, whereas corticosteroids did not induce expression of BAL interferon-gamma. Both ISS and corticosteroids significantly reduced levels of interleukin-5 in BAL, as well as the number of Periodic Acid Schiff-positive airway epithelial cells. Corticosteroids, but not ISS, increased the number of eosinophils in regional mediastinal lymph nodes. Very few apoptotic peribronchial cells were noted following ovalbumin challenge as assessed by TUNEL assay. Corticosteroids, but not ISS, induced an increase in the small number of apoptotic peribronchial cells. The mechanism by which either ISS or corticosteroids inhibit AHR is likely to be mediated by distinct and shared cellular pathways. The combination of the shared and distinct anti-inflammatory pathways may account for the additive effect of ISS and corticosteroids on inhibiting AHR.

The Effects of Long-Term Treatment by Immunotherapy and Fluticazone on Broncial Hyperreactivity

Thirty subjects (20 female and 10 male), all allergic to the mites D. Pteronyssinus and D. Farinae, participated in the present study which covered a period of four years. The subjects were randomly divided in two groups. Group I included 10 female and 5 male subjects, with an average age of 25.8 (+/− 3.5) years who received immunotherapy only. Group II had an average age of 31.5 (+/− 4) years and they received immunotherapy along with fluticazone propionate (1000mcg/day). The protocol for immunotherapy was the same for both groups. The basis FEV1 was determined for each subject of both Groups I and II and afterwards they were subjected to provocation tests of nebulized methacholine solution administered in consecutively larger concentrations until a drop in FEV1 >20 % (PC20), was observed. Three years later, when their therapy was completed, all subjects were subjected to the same provocation test and a significant reduction in bronchial hyperactivity was documented for both groups. In particular, for Group I, the percentage of change in FEV1 values was 27.25 +/- 5.23 % and PC20 5.11 +/− 2.64 mg/ml before immunotherapy, while after immunotherapy the same indicators were 22.22 +/- 7.08 % (P<0.05) and 6.85 +/− 4.03 mg/ml, (P<0.05) respectively. For Group II, the percentage of change in FEV1 values was 26.28 +/− 2.5 % and PC20 5.42 +/− 2.5 mg/ml before immunotherapy, while after immunotherapy the same indicators were 12.27 +/- 2.49 % (P<0.01)and 11.64 +/− 5.14 mg/ml, P<0.01 respectively. It is concluded that although significant reduction in hyperreactivity can be achieved through immunotherapy, the combination of immunotherapy with daily fluticazone propionate administration shows the most promising results.