Low-dose 5-fluorouracil ameliorates Th2 responses through the induction of apoptotic cell death of lung monocyte-derived dendritic cells in asthma.

5-Fluorouracil (5-FU) is an analog of pyrimidine and has been shown to display antitumor and immunomodulatory effects. However, the impacts of 5-FU in regulating asthma, an inflammatory disease associated with T helper cell 2 (Th2) responses, remain unclear. Here, we determine the modulatory effects of low-dose 5-FU on Th2 cell responses in asthma and delineate the underlying mechanisms using adoptive cell transfer and in vitro culture experiments. Our data show that low-dose 5-FU treatment not only inhibits the induction of asthma in allergen-sensitized mice but also abrogates the major features of asthma in mice with established disease. We find that this protection of 5-FU treatment against asthma is accompanied by a decrease in the number of lung monocyte-derived dendritic cells (moDCs) in the asthmatic murine. Furthermore, we show that adoptive transfer of moDCs reverses the inhibitory effects of 5-FU treatment on Th2 cell responses in asthmatic mice. Surprisingly, 5-FU treatment does not suppress surface maturation markers and immunogenicity of moDCs in the lungs of asthmatic mice. Instead, it induces apoptotic cell death of mouse moDCs both in vitro and in vivo. In addition to its impact on mouse moDCs, we observe that low-dose 5-FU treatment can induce apoptotic cell death of human moDCs derived from peripheral blood mononuclear cells in vitro. Together, our findings reveal that low-dose 5-FU ameliorates Th2 cell responses, which may be at least partially related to the induction of apoptotic cell death of moDCs in asthma.

Anti-F4/80 treatment attenuates Th2 cell responses: Implications for the role of lung interstitial macrophages in the asthmatic mice.

Lung interstitial macrophages (IMs) can be polarized towards an alternative activation phenotype in ovalbumin (OVA)-induced asthmatic mice. However, the role of alternative activation of lung IMs in Th2 cell responses in the asthmatic murine is still unclear. Here, we leverage an anti-F4/80 treatment which has been shown to selectively deplete IMs in mice and investigate how this treatment modulates Th2 cell responses in lung and whether the modulation is dependent on lung IMs in murine models of asthma. We show that anti-F4/80 treatment alleviates Th2 cell responses in mice immunized and challenged with OVA or house dust mite (HDM). The anti-F4/80 treatment does not target lung alveolar macrophages (AMs) in OVA-induced asthmatic mice or impact the abundance of other immune cell types, including B cells, T cells, and NK cells in wild-type mice. However, this treatment does inhibit the expression of polarized markers of alternatively activated macrophages, including arginase-1, Ym-1, and Fizz-1 in the lung tissues from OVA-induced asthmatic mice. Furthermore, we find that the inhibitory effects of anti-F4/80 treatment on Th2 cell responses can be reversed upon adoptive transfer of lung IMs. Taken together, our data show that anti-F4/80 treatment attenuates Th2 cell responses, which is at least partially related to depletion of lung IMs in murine models of asthma. This suggests that targeted lung IMs may provide a potential therapeutic protocol for the treatment of asthmatics.

The Clinical Role of Changes of Maximum Expiratory Flow at 25% and 50% of Vital Capacity before and after Bronchodilator Reversibility Test in Diagnosing Asthma.

Changes of maximum expiratory flow at 25% and 50% of vital capacity (MEF25 and MEF50, respectively), and predominant parameters indicating small airways function in asthmatics before and after bronchodilator (BD) reversibility test have been less interpreted. Our study aimed to investigate the clinical role of changes of MEF25 and MEF50 before and after BD reversibility test in diagnosing asthma. Forced expiratory volume in the first second (FEV1), MEF25, and MEF50 were measured before and after BD reversibility test in 207 asthmatic patients using standard process. Forty healthy individuals were enrolled as controls. Receiver operating characteristic (ROC) curve was used to assess the diagnostic accuracy of reversibility of MEF25 and MEF50 before and after BD reversibility test (ΔMEF25% and ΔMEF50%, respectively) in diagnosing asthma. Among these functional criteria, ΔMEF25% and ΔMEF50% ≥ 25% performed the best diagnostic performance. The sensitivity, specificity, and accuracy of ΔMEF25% ≥ 25% as an objective diagnostic test for asthma were 63.29%, 87.50%, and 67.21%, and of ΔMEF50% ≥ 25% were 79.23%, 85.00%, and 80.16%, respectively. The area under the ROC curve of the indicators was 0.8203 and 0.9104, respectively. By contrast, an increase in FEV1 ≥ 12% and 200 mL demonstrated a sensitivity of 62.32%, specificity of 82.50%, and accuracy of 65.59% in diagnosing asthma. The changes of MEF25 and MEF50 before and after BD reversibility test may be of additional value in the clinical diagnosis of asthma, with cutoff values of 25% being the most.

Blockade of CD40L inhibits immunogenic maturation of lung dendritic cells: Implications for the role of lung iNKT cells in mouse models of asthma.

Some studies have shown that maturation of dendritic cells (DCs) is modulated directly by pathogen components via pattern recognition receptors such as Toll-like receptors, but also by signal like CD40 ligand (CD40 L or CD154) mediated by activated T cells. Several reports indicate that invariant natural killer T (iNKT) cells up-regulate CD40 L upon stimulation and thereby induce activation and maturation of DCs through crosslink with CD40. Our previous findings indicated that iNKT cells promote Th2 cell responses through the induction of immunogenic maturation of lung DCs (LDCs) in the asthmatic murine, but its mechanism remains unclear. Therefore, we investigated the immunomodulatory effects of blockade of CD40 L using anti-CD40 L treatment on Th2 cell responses and immunogenic maturation of LDCs, and further analyzed whether these influences of blockade of CD40 L were related to lung iNKT cells using iNKT cell-deficient mice and the combination treatment of specific iNKT cell activation with anti-CD40 L treatment in murine models of asthma. Our findings showed that blockade of CD40 L using anti-CD40 L treatment attenuated Th2 cell responses in wild-type (WT) mice, but not in CD1d-deficient mice sensitized and challenged with ovalbumin (OVA) or house dust mite (HDM). Meanwhile, blockade of CD40 L down-regulated immunogenic maturation of LDCs in WT mice, but not in CD1d-deficient mice sensitized and challenged with OVA. Additionally, agonistic anti-CD40 treatment reversed the inhibitory effects of anti-CD40 L treatment on Th2 cell responses and LDC activation in an OVA-induced mouse model of asthma. Furthermore, LDCs from asthmatic mice treated with anti-CD40 L could significantly reduce the influence on Th2 cell responses in vivo and in vitro. Finally, α-Galactosylceramide plus anti-CD40 L treatment stimulated lung iNKT cells, but suppressed Th2 cell responses in the asthmatic mice. Taken together, our data raise an evidence that blockade of CD40 L attenuates Th2 cell responses through the inhibition of immunogenic maturation of LDCs, which may be at least partially related to lung iNKT cells in murine models of asthma.

Application of Inflammatory Markers in Induced Sputum in Stable Chronic Obstructive Pulmonary Disease Patients with Positive Bronchodilation Tests.

Positive bronchodilation (BD) tests can be noticed in some stable chronic obstructive pulmonary disease (COPD) patients. The characteristics of airway inflammation in this entity remain unclear. Our study aimed to identify the characteristics of airway inflammation in stable COPD patients with positive BD tests. The airway inflammation was assessed in 88 patients with stable COPD using the examination of induced sputum in the aftermath of lung function and BD tests. Cellular counts and the levels of molecular markers including eosinophil cationic protein (ECP), myeloperoxidase (MPO), interleukin-5 (IL-5), and IL-8 were assayed by Wright's stain, Immuno-CAP system, and ELISA, RT-PCR. Among the 88 patients with stable COPD, 20 (22.7%) showed positive BD tests. The values of eosinophils (4.7%±3.4%) and ECP (90.1±41.6 ng/mL) in induced sputum in stable COPD patients with positive BD tests were markedly elevated as compared with those in stable COPD patients with negative BD tests or in healthy controls (all P>0.05), but significantly lower than those in asthmatic patients (all P<0.01). The IL-5 in sputum supernatant was significantly decreased in stable COPD patients with positive BD tests as compared with the patients with asthma (12.5±7.8 vs. 48.2±26.0 ng/mL;.P<0.01). However, healthy controls exhibited similar concentrations of IL-5 in induced sputum with patients with stable COPD, whether with positive or negative BD tests (all P>0.05). Moreover, the values of neutrophils (61.8%±15.1%), MPO (574.0±111.8 ng/mL), and IL-8 (32.6±13.4 ng/mL) in induced sputum in stable COPD patients with positive BD tests were significantly higher than those in asthmatics or normal controls (all P<0.01). However, the values of the above inflammatory markers in induced sputum were similar among stable COPD patients with positive or negative BD tests (all P>0.05). The stable COPD patients with positive BD tests may present not only eosinophilic airway inflammation but also neutrophilic airway inflammation.

α-Galactosylceramide treatment before allergen sensitization promotes iNKT cell-mediated induction of Treg cells, preventing Th2 cell responses in murine asthma.

Asthma is a common inflammatory pulmonary disorder involving a diverse array of immune cells such as proinflammatory T helper 2 (Th2) cells. We recently reported that intraperitoneal injection of α-galactosylceramide (α-GalCer) can stimulate the lung invariant natural killer T (iNKT) cells and does not lead to airway inflammation in WT mice. Other studies indicate that iNKT cells play an important role in inducing regulatory T cells (Treg cells) and peripheral tolerance. Using iNKT cell- knockout mice, functional inactivation of Treg cells, and co-culture experiments in murine asthma models, we investigated the immunoregulatory effects of α-GalCer treatment before allergen sensitization on Th2 cell responses. We also studied whether α-GalCer's effects require lung Treg cells induced by activated iNKT cells. Our results disclosed that intraperitoneal administration of α-GalCer before allergen sensitization could promote the expansion and suppressive activity of lung CD4+FoxP3+ Treg cells. These effects were accompanied by down-regulated Th2 cell responses and decreased immunogenic maturation of lung dendritic cells in WT mice. However, these changes were absent in CD1d-/- mice immunized and challenged with ovalbumin or house dust mites, indicating that the effects of α-GalCer on Treg cells mainly require iNKT cells. Moreover, functional inactivation of Treg cells could reverse the inhibitory ability of this α-GalCer therapy on Th2 cell responses in a murine asthma model. Our findings indicate that intraperitoneal administration of α-GalCer before the development of asthma symptoms induces the generation of lung Treg cells via iNKT cells and may provide a potential therapeutic strategy to prevent allergic asthma.

α-galactosylceramide generates lung regulatory T cells through the activated natural killer T cells in mice.

Our previous study showed that intraperitoneal injection of α-galactosylceramide (α-GalCer) has the ability to activate lung iNKT cells, but α-GalCer-activated iNKT cells do not result in airway inflammation in wild-type (WT) mice. Many studies showed that iNKT cells had the capacity to induce Treg cells, which gave rise to peripheral tolerance. Therefore, we examined the influence of intraperitoneal administration of α-GalCer on the expansion and suppressive activity of lung Treg cells using iNKT cell-knockout mice and co-culture experiments in vitro. We also compared airway inflammation and airway hyperresponsiveness (AHR) after α-GalCer administration in specific anti-CD25 mAb-treated mice. Our data showed that intraperitoneal injection of α-GalCer could promote the expansion of lung Treg cells in WT mice, but not in iNKT cell-knockout mice. However, α-GalCer administration could not boost suppressive activity of Treg cells in WT mice and iNKT cell-knockout mice. Interestingly, functional inactivation of Treg cells could induce airway inflammation and AHR in WT mice treated with α-GalCer. Furthermore, α-GalCer administration could enhance iNKT cells to secrete IL-2, and neutralization of IL-2 reduced the expansion of Treg cells in vivo and in vitro. Thus, intraperitoneal administration of α-GalCer can induce the generation of lung Treg cells in mice through the release of IL-2 by the activated iNKT cells.

The role of plasma N-terminal brain natriuretic pro-peptide in diagnosing elderly patients with acute exacerbation of COPD concurrent with left heart failure.

INTRODUCTION: Acute exacerbation of COPD (AECOPD) and left heart failure (LHF) commonly exist together in clinical practice. However, the identification of AECOPD concurrent with LHF is currently challenging. Our study aimed to investigate the role of plasma N-terminal brain natriuretic pro-peptide (NT-proBNP) in diagnosing elderly patients with AECOPD associated with LHF. METHODS AND RESULTS: LHF was diagnosed in patients with AECOPD according to echocardiographic criteria, and the levels of NT-proBNP in plasma were measured by quantitative electrochemiluminescence assay. Among the 655 patients with AECOPD, 158 (24.1%) had comorbid LHF, whether systolic (n=108, 68.4%) or diastolic (n=50, 31.6%). The plasma concentrations of NT-proBNP in elderly patients with AECOPD associated with LHF were markedly elevated, compared with those with only AECOPD (4,542.5 and 763.0 ng/L, respectively, P<0.01). The receiver operating characteristic curve indicated a diagnostic cutoff value of 1,677.5 ng/L of NT-proBNP in plasma for ascertaining the presence of LHF in AECOPD, with a sensitivity of 87.9%, a specificity of 88.5%, and an accuracy of 88.4%. CONCLUSION: The plasma level of NT-proBNP may be a useful indicator in diagnosing AECOPD associated with LHF.